JP2004256961A - Method for producing reinforcing fiber substrate and method for producing composite material by using the substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a reinforcing fiber substrate to obtain a composite material having high impregnation rate of a matrix resin and excellent mechanical properties in high productivity, concretely excellent quality stability, and provide a method for producing a composite material by impregnating a matrix resin to the reinforcing fiber substrate. <P>SOLUTION: The method for the production of a carbon fiber substrate at least contains (A) a step to draw out reinforcing fiber yarns at an original yarn width Wo, (B) a narrowing step to narrow the yarn width to Wn corresponding to >20% and <85% of the original yarn width and (C) a widening step to widen the yarn width to the target width Wt corresponding to >110% of the narrowed width Wn and narrower than the original yarn width Wo. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０１００】
複合材料の力学特性に関し、本実施例のものは非常に高い値を示し、中でも実施例２のものが特にバランスに優れた。一方、比較例１のものは、実施例２〜４よりも大幅にＣＡＩが低く、樹脂材料の寄与は明らかである。
【０１０１】
強化繊維基材のマトリックス樹脂の含浸性、品質安定性および形態安定性については、実施例２、３のものが特に優れた。なお、実施例１のものは、樹脂材料を用いていないので、実施例２、３の同等以下の含浸性、形態安定性であった。すなわち、本発明の最も好ましい態様の一つとしては、実施例２または３のものということができる。
【０１０２】
【発明の効果】
本発明の製造方法によれば、糸条幅を目標幅Ｗｔに正確かつ安定して制御することができるため、強化繊維糸条の隙間やカバーファクターを所望の範囲内に均一に制御でき、すなわち品質安定性に優れ、強化繊維糸条の蛇行、屈曲が抑制し、その真直性に優れる強化繊維基材を得ることができる。このことにより、マトリックス樹脂の含浸性が良好で、力学特性（特に圧縮強度、ＣＡＩ）に優れる複合材料を生産性良く得られるだけでなく、その品質安定性にも優れた強化繊維基材および複合材料を提供できる。
【０１０３】
このような複合材料は、航空機、自動車、船舶等の輸送機器における一次構造部材、二次構造部材、外装部品、内装部品もしくはそれらの部品等に好適である。
【図面の簡単な説明】
【図１】本発明の製造工程の流れを説明する概略工程図である。
【図２】本発明の製造方法にて製造された強化繊維基材の一実施態様の平面図である。
【図３】本発明の製造方法の好ましい実施態様を説明する模式図である。
【符号の説明】
１：引出工程
２：狭幅工程
３：拡幅工程
４：固定工程
２１：強化繊維基材
２２、３２：たて糸（強化繊維糸条）
２３、３３：よこ糸（補助繊維糸条）
２４：樹脂材料
２５：補助たて糸（たて補助繊維糸条）
３１：織機
３４ａ：綜絖
３４ｂ：メール
３５：筬
３６：レピア
３７；織前で開口を規制するバー
３８：ニップロール
３９：駆動ロール[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a method for producing a reinforced fiber base material which not only can obtain a composite material having good resin impregnation and excellent mechanical properties (particularly compressive strength) with good productivity, but also excellent in quality stability and its reinforcement. The present invention relates to a method for producing a composite material using a fiber base material.
[0002]
[Prior art]
BACKGROUND ART A composite material using a reinforcing fiber (hereinafter, referred to as FRP) has been mainly used for aerospace, sports, and sports because it satisfies required characteristics such as excellent mechanical properties and weight reduction. As a molding method excellent in productivity of these FRPs, for example, a resin transfer molding (RTM) molding method can be mentioned. In such an RTM molding method, a matrix resin impregnated with a matrix resin is impregnated by placing a dry reinforcing fiber base material not impregnated with a matrix resin in a mold and forcibly injecting a liquid matrix resin. Then, FRP is formed.
[0003]
However, this RTM molding method is generally excellent in the productivity of FRP. However, if the impregnating property of the reinforcing fiber substrate (eg, dry reinforcing fiber woven fabric) used is poor, not only does the impregnation time become longer, but also the FRP becomes longer. In addition, there has been a problem that voids and the like are generated, the yield is reduced, and the productivity is reduced. To address the above problem, for example, Patent Literature 1 discloses that the impregnating property in the thickness direction is improved by a difference in the opening ratio of the carbon fiber woven fabric. Patent Literature 2 describes that the impregnating property is improved by a gap between carbon fiber yarns in a unidirectional carbon fiber fabric.
[0004]
However, it is difficult to uniformly control such a reinforcing fiber substrate in a state where the aperture ratio and the gap are increased in the production thereof, and the quality is unstable. Here, the non-uniformity of the aperture ratio and the gap means that the space next to the reinforcing fiber yarn is wide or narrow. In other words, when handling the reinforcing fiber base material or injecting the matrix resin, the reinforcing fibers induce meandering and bending relatively particularly between the wide and narrow areas, and locally impair the straightness thereof. Was causing problems. As a result, the properties of the reinforcing fibers cannot be sufficiently exhibited, and the mechanical properties (particularly, compressive strength) of the FRP are impaired.
[0005]
In other words, according to the conventional proposal, a composite material having particularly excellent compressive strength can be obtained with good productivity, and a method for producing a reinforcing fiber base material having excellent quality stability has not been established. I was
[0006]
[Patent Document 1]
JP 2002-37904 A (page 4, paragraph 0014)
[0007]
[Patent Document 2]
JP-A-11-107107 (page 8, paragraph 0068)
[0008]
[Problems to be solved by the invention]
The present invention provides a method for producing a reinforced fiber base material which not only obtains a composite material having good impregnation of a matrix resin and excellent mechanical properties (especially compressive strength) with good productivity but also excellent quality stability. Provided is a method for producing a composite material in which a fiber base material is impregnated with a matrix resin.
[0009]
[Means for Solving the Problems]
The present invention employs the following means in order to solve such a problem. That is, the method for producing a reinforcing fiber substrate of the present invention is a method for producing a reinforcing fiber substrate composed of reinforcing fiber yarns arranged in at least one direction in parallel, and comprises the following (A) to (C) Characterized by passing through the steps of
[0010]
(A) A drawing step of drawing a reinforcing fiber yarn having a raw yarn width Wo.
[0011]
(B) a narrowing step of narrowing the yarn width to a regulation width Wn of more than 20% and less than 85% of the original yarn width Wo.
[0012]
(C) a widening step of widening the yarn width to a target width Wt exceeding 110% of the regulation width Wn and less than the original yarn width Wo.
[0013]
In order to solve the above-mentioned problems, a method for producing a composite material of the present invention is a method for producing a composite material using at least the reinforcing fiber substrate produced by the method, and comprises the following (E) to (G) Characterized by passing through the steps of
[0014]
(E) a setting step of arranging a reinforcing fiber base in a mold to form a cavity;
[0015]
(F) an injection step of injecting the matrix resin into the cavity to impregnate the reinforcing fiber base material with the matrix resin.
[0016]
(G) a solidification step of solidifying the matrix resin to form a composite material.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, the method for producing a reinforcing fiber substrate of the present invention includes at least the following steps (A) to (C). In order to further exhibit the effects of the present invention, the following step (D) can be included at the same time as or after the widening step (C).
[0018]
(A) A drawing step of drawing a reinforcing fiber yarn having a raw yarn width Wo.
[0019]
(B) A narrowing step of narrowing the yarn width to a regulation width Wn that is more than 20% and less than 85% of the original yarn width Wo.
[0020]
(C) A widening step for expanding the yarn width to a target width Wt which is more than 110% of the regulation width Wn and less than the original yarn width Wo.
[0021]
(D) A fixing step of adhering 0.1 to 20% by weight of a resin material to 100% by weight of the reinforcing fiber base to fix the width of the reinforcing fiber yarn.
[0022]
In the present invention, the “reinforcing fiber base material” means a fabric or the like composed of reinforcing fiber yarns arranged in at least one direction, which will be described in detail later.
[0023]
The “elementary yarn width Wo” is the yarn width before drawing out on a bobbin or a beam around which the reinforcing fiber yarn is wound in the drawing step (A) described later, and is the entire width of the reinforcing fiber base material. It means the average value of 50 lines selected at equal intervals over the direction.
[0024]
In addition, the term "yarn width" refers to the width of the reinforcing fiber yarn that is the widest in the vertical direction in the longitudinal direction at that point because the reinforcing fiber yarn may pass through a three-dimensional yarn path. Means the average value of 50 pieces selected at equal intervals over the entire width direction of the reinforcing fiber base material.
[0025]
In general, it is rare to apply a reinforcing fiber yarn dedicated to a use, and it is common to use a commercially available reinforcing fiber yarn for each use. The present invention relates to a method of manufacturing a reinforcing fiber base material having a target width Wt narrower than the original yarn width Wo, by setting the yarn width of the reinforcing fiber yarn having the original yarn width Wo to more than 20% of the original yarn width Wo to 85%. It has been found that the problem of the present invention can be solved by temporarily narrowing the regulation width Wn to a target width Wt that is more than 110% of the regulation width Wn and less than the original yarn width Wo. That is, if the yarn width is controlled so as to directly narrow the target width Wt without narrowing the original width Wo to the regulation width Wn, not only the target width Wt cannot be accurately controlled, but also the stability thereof is inferior. Cannot solve the problem. By setting the target width Wt through the narrowing step (B) and the widening step (C), the target width Wt can be accurately and stably controlled. This makes it possible to uniformly control the gap and the cover factor of the reinforcing fiber yarns described below within a desired range, that is, to have excellent quality stability, meandering and bending of the reinforcing fiber yarns, and excellent straightness thereof. A reinforcing fiber base can be obtained. The composite material using the reinforcing fiber base material thus obtained has an effect of being excellent in mechanical properties, especially in compressive strength.
[0026]
FIG. 1 is a schematic process diagram illustrating the flow of the manufacturing process of the present invention. Each step will be described in detail below.
[0027]
(A) Withdrawal process (1 in FIG. 1)
The reinforcing fiber yarn having the original yarn width Wo is drawn out, for example, directly from a bobbin hanging on a creel stand or from a partially warped beam or the like. Since the width of the reinforcing fiber base is usually 0.2 m to 2.54 m, it is common to use a large number of reinforcing fiber yarns.
[0028]
(B) Narrow width process (2 in FIG. 1)
The yarn width is reduced to a regulation width Wn of more than 20% and less than 85% of the original yarn width Wo. More preferred Wn is more than 30% and less than 65% of Wo, even more preferably more than 35% and less than 50% of Wo. If Wn is 25% or less of Wo, not only the width cannot be increased to the target width Wt in the widening step (C) described later, but also a large amount of fluff is generated from the reinforcing fiber yarns, which makes production difficult. . On the other hand, if it is 85% or more of Wo, the meaning of narrowing the yarn width to Wn becomes sparse, and the effect of the present invention is not exhibited.
[0029]
Means for regulating the yarn width to Wn include passage of a regulation guide, surface tension when applying and drying a liquid, a combination thereof, and the like. A guide having a dimension smaller than the yarn width is preferable. And a method of passing a reinforcing fiber yarn. At least one such guide may be passed, but it is better to pass a plurality of guides in order to achieve a more precise regulation width. In this case, the width reduced to the minimum is defined as the regulation width Wn of the present invention.
[0030]
Examples of such a guide include a comb type and a groove type. In a loom, a heald or a reed can be used as a guide. More preferably, it is better to pass through a heald and a reed having an inner size smaller than the original yarn width Wo. In this case, it is particularly preferable that the inner size of the mail actually passing through the reinforcing fiber yarn in the heald is smaller than the inner size of the reed. That is, when the heald is set to the regulation width Wn and the reed is set to a thread width larger than Wn, the stability in the widening step (C) described later is increased, and the effect of the present invention can be maximized.
[0031]
(C) Widening step (3 in FIG. 1)
The yarn width is increased to a target width Wt exceeding 110% of the regulation width Wn and less than the original yarn width Wo. More preferred Wt is more than 130% of Wn and less than 95% of Wo, even more preferably more than 150% of Wn and less than 90% of the original yarn width Wo. If Wt is 110% or less of Wn, the meaning of widening in this step is diminished, and the effect of the present invention is not exhibited. On the other hand, if it is equal to or more than Wo, the meaning of going through the narrowing step (B) described above becomes sparse, and the effect of the present invention is not exhibited.
[0032]
Means for widening the yarn width to Wt include spraying compressed gas or fluid, passing through a bar (vibration bar, tension fluctuation bar, rubbing bar, etc.), applying vibration (ultrasonic waves, etc.) in liquid, applying pressure, The preferred method is a method in which the reinforcing fiber yarn is passed through a bar having a contact angle of 10 ° or more (hereinafter abbreviated as a widening bar). The bar is a generic name of a bar that comes into contact with a reinforcing fiber yarn such as a roll, a rod, and a plate and has a widening effect. Examples of the widening bar include a fixed type, a free type, and a driving type. In a loom, in particular, a bar or a nip roll that regulates an opening before weaving can be used as the widening bar. More preferably, it passes through a fixed bar and a nip roll that regulate the opening.
[0033]
According to the manufacturing method of the present invention through the above steps (A) to (C), the target width Wt can be accurately and stably controlled. This also makes it possible to uniformly control the gap and the cover factor of the reinforcing fiber yarns described later within a desired range. The composite material using the thus obtained reinforcing fiber base material has an excellent effect of being excellent in mechanical properties, especially in compressive strength.
[0034]
(D) Fixing step (4 in FIG. 1)
The manufacturing method of the present invention can obtain more excellent effects if the fixing step described here is further performed. That is, in the fixing step, the width of the reinforcing fiber yarn is fixed by bonding the resin material. Such a resin material is preferably 0.1 to 20% by weight based on 100% by weight of the reinforcing fiber base material. If the amount is less than 0.1% by weight, the morphological stability of the substrate when handling the reinforcing fiber substrate is poor. If it exceeds 20% by weight, impregnation of the matrix resin may be hindered when obtaining a composite material.
[0035]
Such a resin material may be adhered to the surface (either one side or both sides) of the reinforcing fiber base, or may be coated and bonded over the entire surface of the reinforcing fiber base.
[0036]
When a resin material is adhered to the surface of the reinforcing fiber base, preferred methods include, for example, the following methods (d1) and (d2).
[0037]
(D1) After applying or attaching a solid resin material, the resin material is melted and adhered to the reinforcing fiber yarn. In this case, a nonwoven fabric, a woven fabric, a knitted fabric, a fiber, a particle, or the like can be used as the resin material. It is preferable to use a nonwoven fabric as the resin material because the amount of the resin material can be easily controlled. On the other hand, the use of particles is preferable because it enables microscopically uniform dispersion. As a device for applying particles, any device can be used as long as it can uniformly apply, such as a charged spray, a fluidized bed, a contact roll (such as a kiss roll and a dot roll), and a non-contact roll (such as a scraping roll). FIG. 2 is a plan view of one embodiment of the reinforcing fiber base material manufactured by the manufacturing method of the present invention, in which the particulate resin material is adhered to the non-crimped unidirectional fabric by the method (d1). The resin material 24 is discretely dispersed in a dotted manner on the reinforcing fiber base 21.
[0038]
(D2) A molten resin material is applied and adhered to the reinforcing fiber yarn. In this case, for example, when the melt blow method is used, the nonwoven fabric can be formed and adhered directly and simultaneously to the surface of the reinforcing fiber base, and the process can be performed efficiently.
[0039]
In the case of the methods (d1) and (d2), the resin material is preferably 2 to 20% by weight based on 100% by weight of the reinforcing fiber base material. When the resin material is adhered to the surface of the reinforcing fiber base material by such a method, not only does the width of the reinforcing fiber yarns be fixed and the morphological stability of the base material is developed, but also the resin material is cracked between the base material layers of the composite material. By acting as a stopper, it is possible to suppress damage between layers when receiving an impact, and to exhibit an effect of being excellent in impact resistance characteristics (especially, compression after impact, CAI). Furthermore, the resin material itself serves as a spacer to form a flow path when impregnating the matrix resin, and not only facilitates impregnation, particularly when subjected to injection molding, but also increases the impregnation speed, thereby increasing the degree of impregnation. It also has unexpected effects such as excellent material productivity.
[0040]
On the other hand, in the case of covering and bonding over the entire surface of the reinforcing fiber base material, a preferable method includes, for example, the following method (d3).
[0041]
(D3) After applying a resin material dissolved or dispersed in a solvent, the resin material is removed and adhered to the reinforcing fiber yarn. In this case, it is preferable to use a liquid in which the resin material is dissolved or dispersed at a high concentration because the solvent can be easily removed at low cost. For increasing the concentration, an emulsifier or the like can be used within a range that does not adversely affect the mechanical properties. Further, as the coating device, any device can be used as long as it can uniformly apply, such as a printing device such as an ink jet or a screen, a spray, a contact roll (such as a kiss roll, a touch roll), and among them, a contact roll is most preferable. . Here, the solvent is a generic name of liquids that can dissolve or disperse resin materials such as inorganic solvents, organic solvents, and water.
[0042]
In this case, the resin material is preferably 0.5 to 5% by weight based on 100% by weight of the reinforcing fiber base material. When the resin material is coated and adhered over the entire surface of the reinforcing fiber base material by this method, the width of the reinforcing fiber yarn can be fixed with a smaller amount of the resin material, and the shape stability of the base material can be exhibited. In addition, since the surface tension is applied to the reinforcing fiber yarns at the time of desolvation, an unexpected effect that the gaps and the like of the reinforcing fiber base can be easily and largely controlled is also exhibited.
[0043]
The reinforcing fiber substrate of the present invention is, for example, a two-dimensional unidirectional fabric, a bidirectional fabric, or a fabric having more than one orientation, a three-dimensional multidirectional fabric, a knitted fabric, a multiaxial insertion substrate, and a unidirectional fabric. Examples include aligned reinforcing fiber sheets (unidirectional sheets), multiaxial sheets in which unidirectional sheets are laminated in two or more directions and integrated, and these are joined by stitch yarns, knotting yarns, resin components, and the like. A plurality may be integrated.
[0044]
Particularly when used as a structural member of transportation equipment (especially a primary structural member of an aircraft), very high mechanical properties (compressive strength, CAI, etc.) are required. Due to the weaving structure and the increase in the crimp of the reinforcing fiber yarn at the intersection of the warp and the weft, it may be difficult to develop mechanical properties that can withstand the demand. That is, from the viewpoint that such a problem can be surely solved, the reinforcing fiber base material of the present invention is preferably a unidirectional woven fabric, a unidirectional sheet, or a material in which a plurality of them are integrated. Furthermore, in consideration of the impregnation surface of the matrix resin, the unidirectional woven fabric in which the reinforcing fiber yarns as the warp yarns have regular gaps and have extremely small crimps formed by the entanglement of the warp yarns and the weft yarns is particularly preferable. preferable. Such gaps and extremely small crimps serve as a flow path for impregnation of the matrix resin, and have an effect of remarkably improving impregnation.
[0045]
The unidirectional fabric will be described in more detail. A unidirectional woven fabric is a plain woven structure, a twill woven structure, a satin woven structure, or the like, in which a warp (reinforcing fiber yarn) and a weft yarn (auxiliary fiber yarn) arranged in parallel in one direction intersect with each other. It is what constituted. Auxiliary fiber yarns, which are weft yarns, are used to reduce the bending (crimp) of the warp yarns at the intersections between the warp yarns and the weft yarns and to cut the reinforcing fiber yarns used for the warp yarns in order to maximize the effects of the present invention. Those having an area of 1/10 or less, more preferably 1/100 or less, are preferable. Such a cross-sectional area is the sum of the cross-sectional areas of the single fibers constituting the yarn. The weft density of the weft yarn is preferably 0.3 to 6 yarns / cm from the viewpoint of balance between shape stability and minimization of influence on mechanical properties. More preferably, it is 1 to 4 wires / cm.
[0046]
The unidirectional woven fabric preferably used in the present invention also includes a non-crimp structure described below in addition to the woven structure. A non-crimped unidirectional woven fabric is a warp (reinforcement fiber yarn) in which an auxiliary warp (auxiliary fiber yarn) arranged in parallel with a warp and a weft (auxiliary fiber yarn) orthogonal thereto intersect each other. ) Are held together. According to such a non-crimp structure, the crimp can be made smaller than that of a plain weave structure, so that the effects of the present invention can be further enhanced. In addition, from the aspect of resin impregnation, the presence of the auxiliary warp ensures the impregnation flow path more reliably, and expresses extremely excellent impregnation. The unidirectional fabric itself is described in detail in, for example, JP-A-7-243149.
[0047]
In the reinforcing fiber base material, the basis weight of the reinforcing fiber yarn for maximizing the effect of the present invention is 50 to 350 g / m. ² , Preferably 150 to 270 g / m ² It is.
[0048]
According to the present invention, a target in which the target width Wt is accurately regulated is obtained. As a result, the gap between the reinforcing fiber yarns, the fluctuation rate of the yarn width of the reinforcing fiber yarn, the cover factor, and the like are accurately and stably controlled to manufacture. can do. From such a viewpoint, it is preferable that the reinforcing fiber base material manufactured by the manufacturing method of the present invention is one in which the gap between the reinforcing fiber yarns is controlled to 0.1 to 1 mm. It is more preferably from 0.2 to 0.7 mm, and still more preferably from 0.3 to 0.6 mm. If it is less than 0.1 mm, the impregnating property of the matrix resin is inferior. If it exceeds 1 mm, the gap becomes too large. It is not preferable because cracks occur. Such a gap between the reinforcing fiber yarns refers to a gap between the reinforcing fiber yarns in the base material when the planar reinforcing fiber base material is viewed from a perpendicular direction thereof. The auxiliary fiber yarns, stitch yarns, etc. were treated as if they did not exist, and the average value of 50 fibers selected at equal intervals over the entire width direction of the reinforcing fiber base material was used.
[0049]
Further, the reinforcing fiber base material manufactured by the manufacturing method of the present invention is preferably one in which the fluctuation rate of the yarn width of the reinforcing fiber yarn is controlled to 0 to 10%. It is more preferably 0 to 9%, and still more preferably 0 to 8%. If it exceeds 10%, when a composite material is used, there is a problem of void formation due to a difference in the impregnation rate of the matrix resin between a thin portion and a thick portion of the reinforcing fiber yarn, and a relative increase in the reinforcing fiber yarn. Induces meandering and flexing, locally inhibiting straightness. The yarn width refers to the width of the planar reinforcing fiber substrate as viewed from the perpendicular direction, and an average value of 50 yarns selected at equal intervals over the entire width direction of the reinforcing fiber substrate was used. The fluctuation rate is obtained by measuring the yarn width at 20 locations at 25 mm intervals in the longitudinal direction of the reinforcing fiber yarn, and using the variance and the average thereof, (variation rate) = (dispersion) × 100 / (average) Was calculated.
[0050]
The reinforcing fiber substrate produced by the production method of the present invention preferably has a cover factor controlled to be more than 80% and less than 95%. More preferably, it is 85 to 94%, and still more preferably 90 to 93%. If it is less than 80%, it means that the composite material will be deteriorated in mechanical properties and thermal cracks will occur, and if it is more than 95%, the impregnating property of the matrix resin will be poor. Here, the cover factor refers to the reinforcing fiber yarns (auxiliary fiber yarns, warp auxiliary fiber yarns) in the base material in a unit area of 200 mm × 200 mm when the planar reinforcing fiber base material is viewed from the perpendicular direction. Refers to the percentage of the closed part where the strips, stitch yarns, etc. are present (not covered), and the cover factor (%) = the total area of the closed part (mm) ² ) / 400. In the present invention, the average value measured at four points at equal intervals over the entire width direction of the reinforcing fiber base is represented. Such a closed portion can be calculated based on an image optically captured by a CCD camera, a scanner, or the like.
[0051]
As the reinforcing fiber yarn used in the present invention, for example, carbon fiber, graphite fiber, glass fiber, organic fiber (aramid, paraphenylene benzobisoxazole, polyvinyl alcohol, high-strength polyethylene, polyimide, etc.), two or more of these are used in combination. Can be used. Among them, carbon fibers are excellent in specific strength and specific elastic modulus, and thus are preferably used as reinforcing fibers for aircraft applications.
[0052]
Such a carbon fiber thread can be used in a non-twisted or twisted form, but is preferably substantially untwisted in terms of mechanical properties (tensile, compressive, etc.). Further, the fineness is preferably 300 to 5,000 tex. More preferably, it is 600 to 2,000 tex. If it is smaller than this range, in the case of fabrics, the number of crossing points is so large that not only the crimps but also the number of crimps are increased, and the mechanical properties may be poor. If it is larger than the above range, the number of crossing points may be too small and the reinforcing fiber substrate may have poor form stability.
[0053]
As the warp auxiliary fiber yarn or the auxiliary fiber yarn used in the present invention, as described above, the cross-sectional area of the reinforcing fiber yarn (multiplied by the number of cross-sectional areas of single fibers) is preferably 1/10 or less, If it is more preferably 1/100 or less, the same material as the reinforcing fiber yarn can be used. Since the reinforcing effect as a reinforcing fiber is not strongly required, in addition to them, polyamide (undrawn yarn, drawn yarn, POY (semi-drawn yarn by high-speed spinning), etc.), polyester, phenol, and these are used as core-sheath yarn. Organic fibers such as those can be used alone or in combination.
[0054]
The resin material used in the present invention is not particularly limited as long as it improves the morphological stability of the reinforcing fiber base material and does not impair or improve the mechanical properties of the composite material. A plastic resin can be used.
[0055]
As the thermosetting resin, for example, epoxy, phenol, polybenzimidazole, cyanate ester, unsaturated polyester, vinyl ester, urea, melamine, bismaleimide and the like, and copolymers, modified products and blends of two or more thereof Resin or the like can be used. Further, those to which an elastomer, a rubber component, a curing agent, a curing accelerator, a catalyst and the like are added can also be used.
[0056]
As the thermoplastic resin, for example, polyester, polyolefin, polyamide, polyurethane, polycarbonate, polyphenylene sulfide, polyphenylene ether, polyetherimide, polysulfone, polyarylate, polyethersulfone, polyetherethersulfone, polyketone, polyetherketone, polyether Ether ketone, polyether ketone, polyether nitrile, phenol (novolak type), phenoxy resin, styrene resin, acrylic resin, fluorine resin, etc., and copolymers, modified products thereof, and resins obtained by blending two or more kinds are also available. Can be used.
[0057]
As a preferred example of the resin material that maximizes the object of the present invention, a thermosetting resin and a thermoplastic resin are mixed, preferably compatibilized, and have a glass transition point of 30 to 100 ° C, more preferably What carried out 50-90 degreeC is mentioned. Such a resin material not only easily adheres to the reinforcing fiber base material, but also exhibits an extremely excellent effect of improving mechanical properties when an epoxy resin is used as a matrix resin described later.
[0058]
As a more preferred embodiment, the method for producing a composite material of the present invention can include the following steps (E) to (G).
[0059]
(E) Setting process
The cavity is formed by arranging the reinforcing fiber base material manufactured by the above method in a mold. In the present step, when a male mold and a female mold are used as a molding die, a composite material having excellent dimensional accuracy and inexpensive as compared with the conventional autoclave molding can be molded.
[0060]
On the other hand, it is preferable to use either a male mold or a female mold and a bag material as the mold, because the cost of the mold can be reduced and the cost can be further reduced. Examples of such a bag material include a film and a flexible rubber material. Since the bag material is usually flexible, a plate or the like for imparting rigidity to the surface on the bag material side can be used together. By using such a plate together, it is possible to achieve the same level of dimensional accuracy as when a mold is used on both sides.
[0061]
In the latter case, it is not possible to apply pressure to the matrix resin to inject the matrix resin. Therefore, it is preferable to arrange a resin diffusion medium for promoting the impregnation of the matrix resin in the cavity. Such a resin diffusion medium refers to a medium having a high space retention ability (having irregularities on the surface) and a flow resistance of a matrix resin of 1/10 or less of that of a reinforcing fiber base material. Non-woven fabrics and the like are given as examples.
[0062]
(F) Injection process
A matrix resin is injected into the cavity to impregnate the reinforcing fiber substrate with the matrix resin. In this process, when degassing with a vacuum pump or the like and injecting the matrix resin while keeping the inside of the cavity under reduced pressure, the impregnation of the matrix resin into the reinforcing fiber base material becomes easy, and a higher-quality composite material can be shortened in a short cycle. It is preferable because the molding cost can be further reduced.
[0063]
(G) Solidification process
The matrix material is solidified (cured or polymerized) to obtain a composite material. Here, when the matrix resin is solidified, heating is preferably performed to increase the solidification efficiency. If necessary, in order to further secure the solidification of the matrix resin, a secondary solidification step of heating the composite material again to further solidify the composite material may be performed.
[0064]
The matrix resin used in the present invention is preferably a thermosetting resin in view of its moldability and mechanical properties, and those exemplified in the resin materials are preferably used. The difference from the resin material is that, when subjected to injection molding, it must be liquid at the injection temperature. As the thermosetting resin having such properties, epoxy, imide, phenol, vinyl ester, unsaturated polyester, and cyanate ester are preferable. Those obtained by further adding an elastomer, a rubber component, a curing agent, a curing accelerator, a catalyst, and the like to these resins can also be used. Among them, epoxy, bismaleimide or cyanate ester is preferable, and epoxy is particularly preferable, in order to achieve very high mechanical properties required for primary structural members of aircraft and the like.
[0065]
It is preferable that the matrix resin and the resin material be different in consideration of their different roles. That is, a matrix resin having excellent impregnation properties (low resin viscosity at the injection temperature and a long gelling time) and a resin material improving the form stability of the reinforcing fiber substrate are selected and used. Is preferred. Of course, in the matrix resin and the resin material, the use of the same component for a part thereof is not limited at all, and it can be said that it is a preferable embodiment in terms of compatibility between the two.
[0066]
【Example】
(Example 1)
FIG. 3 is a schematic diagram illustrating a preferred embodiment of the production method of the present invention, and shows a state where a reinforcing fiber base material is produced using a loom 31. Next, each step will be described in detail.
[0067]
(A) Pull-out step: 183 warp yarns 32 and 183 auxiliary warp yarns (not shown) were arranged in parallel and alternately, and were drawn directly from each bobbin so as to have a width of 1 m. The yarn width (original yarn width Wo) of the reinforcing fiber yarn on the bobbin was 6.6 mm.
[0068]
As the warp yarn 32, a PAN-based carbon fiber yarn (24,000 filaments, fineness of 1,035 tex, tensile strength of 5,900 MPa, tensile modulus of elasticity of 294 GPa) as a reinforcing fiber yarn was used. In addition, as an auxiliary warp yarn, a glass fiber yarn (ECE225 1/0 1.0Z, fineness 22.5tex, binder type DP, manufactured by Nitto Boseki) which is a warp auxiliary fiber yarn was used.
[0069]
(B) Narrow Width Step: The warp yarn 32 is passed through the heald 34a (the inner dimension of the mail 34b is 2.5 mm) as a guide to reduce the yarn width to the regulated width of 2.5 mm (38% of the original yarn width Wo). I narrowed it. Subsequently, the reed 35 was passed through a reed 35 (the inner dimension of the portion through which the thread passes (the reed blade gap) was 3 mm) to make it 3 mm (45% of the original thread width Wo).
[0070]
Here, weft yarns 33 were driven at a weave density of 3 yarns / cm using a rapier 36 and crossed with an auxiliary warp yarn to form a unidirectional woven fabric having a non-crimp structure in which the warp yarns 32 were integrally held. In addition, as the weft yarn 33, a polyamide fiber yarn (polyamide 66, 7 filaments, fineness 1.7 tex) as an auxiliary fiber yarn was used.
[0071]
(C) Widening step: The yarn width is regulated by the bar 37 (maximum contact angle 20 °), the nip roll 38 (contact angle 90 ° or more) and the drive roll 39 to the target width Wt of 5.1 mm (regulation). The width was increased to 204% of the width Wn and 77% of the original yarn width Wo).
[0072]
The basis weight of the reinforcing fiber yarn in the obtained reinforcing fiber base material was 188 g / m 2, the gap between the reinforcing fiber yarns was 0.4 mm (measured assuming that the auxiliary fiber yarn did not exist), and the fluctuation rate of the yarn width was 8% and the cover factor was 91%.
[0073]
(Example 2)
In the following (D) fixing step 1, a resin material was applied and adhered to the reinforcing fiber base material as the unidirectional woven fabric obtained in Example 1 to fix the width of the reinforcing fiber yarn.
[0074]
(D) Fixing step 1: The particle-shaped resin material is dropped naturally while being measured by an embossing roll and a doctor blade, and is uniformly dispersed through a vibrating net while being 26 g / m2 on one surface. ² (12% by weight based on 100% by weight of the reinforcing fiber base after the resin material is attached). Thereafter, the resin material was passed through a far-infrared heater at 185 ° C. to adhere the resin material to only one surface of the reinforcing fiber base material.
[0075]
The obtained reinforcing fiber base material had remarkably improved morphological stability due to the resin material, was extremely excellent in handling than that of Example 1, and the reinforcing fiber yarn was excellent in straightness. Further, the yarn width was stable in the longitudinal direction and the width direction, and was excellent in quality stability. The basis weight of the reinforcing fiber yarn is 190 g / m. ² The gap between the reinforcing fiber yarns was 0.4 mm, the fluctuation rate of the yarn width was 6%, and the cover factor was 93%.
[0076]
As the particulate resin material, a mixture of 60% by weight of a polyether sulfone resin and 40% by weight of an epoxy resin composition, which was freeze-ground and used. Such a particulate resin material has an average particle diameter D ₅₀ (Laser diffraction / scattering method) 115 μm, glass transition point 68 ° C.
[0077]
(Example 3)
A different resin material was further applied and adhered to the reinforcing fiber base material obtained in Example 2 in the following (D) fixing step 2 to fix the width of the reinforcing fiber yarn more firmly.
[0078]
(D) Fixing step 2: A resin material dispersed in a solvent is applied by spraying, and the solvent is dried in an oven at 180 ° C. to obtain a resin material (solid content) of 1.7 g / m. ² (0.8% by weight based on 100% by weight of the reinforcing fiber base material after the resin material is attached).
[0079]
The obtained reinforcing fiber base material was excellent in form stability as in Example 2. The yarn width was more stable in the longitudinal direction and the width direction than in Example 2, and was further excellent in quality stability. The basis weight of the reinforcing fiber yarn is 192 g / m ² The gap between the reinforcing fiber yarns was 0.6 mm, the fluctuation rate of the yarn width was 4%, and the cover factor was 89%.
[0080]
As a resin material dispersed in a solvent, a resin composition (50 parts by weight of "Epicoat" 828 manufactured by Japan Epoxy Resin Co., Ltd. and 50 parts by weight of unsaturated polyester) in 98% by weight of a solvent (water). 7% by weight was dispersed in a solvent (water) with 0.3% by weight of an emulsifier.
[0081]
(Example 4)
(A) Pulling-out step: A warp was drawn out in the same manner as in Example 1.
[0082]
(B) Narrow width step: The warp yarn is made to pass through a comb, which is a comb-shaped guide (the inner diameter of a portion where the yarn passes is 3 mm), so that the yarn width becomes 3 mm of the regulation width Wn (45% of the original yarn width Wo). I narrowed it.
[0083]
(C) Widening step and (D) Fixing step 3: A nonwoven fabric resin material bonded to both sides of a aligned reinforcing fiber yarn is sandwiched by release paper, and pressed at 180 ° C. and a linear pressure of 0.2 MPa. After passing through the roll, the yarn width is widened to 5.2 mm of the target width Wt (173% of the regulation width Wn, 78% of the original yarn width Wo), and at the same time, the width of the reinforcing fiber yarn is adhered to the resin material on the surface. Was fixed.
[0084]
As the non-woven resin material, the thermoplastic resin used in Example 2 was formed into a non-woven fabric by melt blowing (13 g / m 2). ² ) Was used.
[0085]
The obtained reinforcing fiber base material had significantly improved morphological stability due to the resin material, and was easy to handle. Moreover, the reinforcing fiber yarn was excellent in straightness. Further, the yarn width was stable in the longitudinal direction and the width direction, and was excellent in quality stability. The basis weight of the reinforcing fiber yarn is 190 g / m. ² The gap between the reinforcing fiber yarns was 0.3 mm, the fluctuation rate of the yarn width was 5%, and the cover factor was 94%.
[0086]
(Example 5)
Using the reinforcing fiber base material manufactured in Examples 1 to 4, a composite material was formed by the following method.
[0087]
A reinforcing fiber substrate was laminated on the surface of the aluminum mold in the following constitutions 1 and 2. On the outermost surface thereof, a peel ply (a woven fabric subjected to a release treatment of polyester fibers) and a resin diffusion medium (a mesh sheet made of polypropylene) were arranged in this order, and an aluminum cowl plate was further arranged thereon. A plurality of edge breathers (non-woven fabric of polyester fiber) were laminated and stretched around the periphery of the laminated reinforcing fiber substrate in contact with the mold. The maximum outer shape in plan view of the resin diffusion medium is larger than the maximum outer shape in plan view of the reinforcing fiber base of the resin diffusion medium so that the distance from the vacuum suction port or the edge breather to the nearest resin diffusion medium is at least 10 mm away. It was arranged to be about 10 to 50 mm smaller. The whole was covered with a bag material (nylon film), and the periphery of the bag material and the mold was sealed with a sealing material to form a cavity. The resin injection port was attached so as to be in contact with the resin diffusion medium, and was sealed with a sealing material. The vacuum suction port was mounted on the edge breather farthest from the resin inlet and was similarly sealed. Suction was performed through the vacuum suction port, and the inside of the cavity was suctioned. The entire apparatus was heated to the matrix resin injection temperature (80 ° C.). While continuing the vacuum suction, the reinforcing fiber substrate was held for one hour after reaching the injection temperature. After that, the valve at the resin injection port was opened to mix and defoam beforehand, and a required amount of the matrix resin prepared in an injectable state was injected from the resin diffusion medium. When the impregnation was completed, the valve at the resin inlet was closed to stop the injection. The vacuum suction was continued until the matrix resin gelled (1.5 hours from the start of the injection). Thereafter, the temperature was raised to the curing temperature (130 ° C.) of the matrix resin, and maintained for 2 hours to cure the matrix resin. When the temperature reached the curing temperature, the vacuum suction port was closed to stop the suction, and the inside of the bag material was kept in a vacuum state. Thereafter, the temperature was lowered to room temperature, and the bag material, the peel ply and the resin impregnated medium were removed to obtain a composite material.
[0088]
Lamination structure 1: [0 °] ₆ , Total 6 layers, 150m x 150mm.
[0089]
Lamination structure 2: [-45 ° / 0 ° / + 45 ° / 90 °] _3S , Total 24 layers, 370 mm x 370 mm.
[0090]
Inspection of the obtained composite material showed no pinholes or voids anywhere, demonstrating that extremely good molding was performed.
[0091]
Next, the compressive strength of the test piece along the SACMA-SRM-1R-94 was measured from the composite material of the laminate configuration 1. Further, the compressive strength (CAI) of the test piece along the SACMA-SRM-2R-94 from the composite material having the laminated structure 2 after impact was measured. Table 1 shows the results. As the matrix resin, an epoxy resin composition (using a polyamine as a curing agent and a viscosity of 55 mPa · s at 80 ° C. by an E-type viscometer) was used.
[0092]
(Comparative Example 1)
(A) Pulling-out step: 274 warp yarns were arranged in parallel and drawn directly from each bobbin so as to have a width of 1 m. The original yarn width Wo, which is the width of the reinforcing fiber yarn on the bobbin, was 6.6 mm. The same warp yarn as in Example 1 was used.
[0093]
(B) Narrowing step: The warp yarn was passed through a heald (inner dimension of the mail was 5 mm) as a guide and narrowed to 5 mm. Next, the thread width was reduced to 3.5 mm of the regulation width (53% of the original thread width Wo) by passing through a reed (the inner dimension of the portion where the thread passes (reed blade gap) is 3.5 mm). .
[0094]
A unidirectional woven fabric having a plain weave structure was formed in the same manner as in Example 1 except that the same glass fiber thread as in Example 1 was used as the weft, and no warp yarn was used and the warp yarn and the weft yarn were crossed.
[0095]
(C) Widening step: The thread width is passed through a nip roll (contact angle of 90 ° or more) and a driving roll without using a bar for regulating the opening before weaving, and the yarn width is set to 3.6 mm of the target width Wt (103 of the regulation width Wn). %, 55% of the original yarn width Wo).
[0096]
The obtained reinforcing fiber yarn of the reinforcing fiber base material was particularly constricted at the point of intersection with the weft yarn, and the yarn was gourd-like and inferior in straightness. In addition, the gaps between the reinforcing fiber yarns were not uniformly present but partially existed at about 0.1 to 0.2 mm, which was inferior in quality stability. Reinforced fiber yarn weight is 285g / m ² The variation rate of the yarn width was 12%, and the cover factor was 98%.
[0097]
(Comparative Example 2)
Using the reinforcing fiber base material produced in Comparative Example 1, a composite material was formed in the same manner as in Example 5 except that the following laminated structure 3 was used instead of the laminated structure 2. Table 1 shows the compressive strength and CAI of the composite material.
[0098]
Lamination structure 3: [−45 ° / 0 ° / + 45 ° / 90 °] 2S, 16 layers in total, 370 mm × 370 mm.
[0099]
[Table 1]

[0100]
With respect to the mechanical properties of the composite material, the one in this example showed a very high value, and the one in Example 2 was particularly excellent in balance. On the other hand, in the case of Comparative Example 1, the CAI is significantly lower than in Examples 2 to 4, and the contribution of the resin material is clear.
[0101]
With respect to the impregnating property, quality stability and form stability of the matrix resin of the reinforcing fiber base, those of Examples 2 and 3 were particularly excellent. In the case of Example 1, the resin material was not used, so that the impregnation property and form stability were equal to or less than those of Examples 2 and 3. That is, it can be said that one of the most preferable aspects of the present invention is that of Example 2 or 3.
[0102]
【The invention's effect】
According to the production method of the present invention, since the yarn width can be accurately and stably controlled to the target width Wt, the gap and the cover factor of the reinforcing fiber yarn can be uniformly controlled within a desired range, that is, the quality It is possible to obtain a reinforcing fiber base material which is excellent in stability, suppresses meandering and bending of the reinforcing fiber yarn, and has excellent straightness. As a result, a composite material having good matrix resin impregnation properties and excellent mechanical properties (particularly, compressive strength and CAI) can be obtained with good productivity, and a reinforced fiber base material and a composite material having excellent quality stability can be obtained. Material can be provided.
[0103]
Such a composite material is suitable for a primary structural member, a secondary structural member, an exterior component, an interior component, or a component thereof in transport equipment such as an aircraft, an automobile, and a ship.
[Brief description of the drawings]
FIG. 1 is a schematic process diagram illustrating a flow of a manufacturing process of the present invention.
FIG. 2 is a plan view of one embodiment of a reinforcing fiber base manufactured by the manufacturing method of the present invention.
FIG. 3 is a schematic view illustrating a preferred embodiment of the production method of the present invention.
[Explanation of symbols]
1: Withdrawal process
2: Narrow width process
3: Widening process
4: Fixing process
21: Reinforced fiber base material
22, 32: warp yarn (reinforced fiber yarn)
23, 33: weft (auxiliary fiber yarn)
24: resin material
25: auxiliary warp yarn (warp auxiliary fiber yarn)
31: Loom
34a: Heald
34b: Email
35: Reed
36: Rapier
37; Bar for regulating the opening on the cloth fell
38: Nip roll
39: drive roll

Claims (15)

What is claimed is: 1. A method for producing a reinforcing fiber base comprising reinforcing fiber yarns arranged in at least one direction in parallel, wherein the method comprises the following steps (A) to (C). Production method.
(A) A drawing step of drawing a reinforcing fiber yarn having a raw yarn width Wo.
(B) a narrowing step of narrowing the yarn width to a regulation width Wn of more than 20% and less than 85% of the original yarn width Wo.
(C) a widening step of widening the yarn width to a target width Wt exceeding 110% of the regulation width Wn and less than the original yarn width Wo. The method for producing a reinforcing fiber base according to claim 1, wherein the narrowing step (B) is to pass the reinforcing fiber yarns through a guide having a dimension smaller than the original yarn width Wo. 3. The method for producing a reinforcing fiber base according to claim 1, wherein the widening step of (C) passes the reinforcing fiber yarn through a bar having a contact angle of 10 ° or more. 4. The bar according to any one of claims 1 to 3, wherein the guide is a heald and / or a reed in a loom, and the bar having a contact angle of 10 ° or more is a bar and a nip roll for regulating an opening before weaving in the loom. The method for producing a reinforcing fiber base according to the above. The method for producing a reinforcing fiber substrate according to any one of claims 1 to 4, further comprising the following step (D) simultaneously with or after the step of widening (C).
(D) A fixing step of adhering 0.1 to 20% by weight of a resin material to 100% by weight of the reinforcing fiber base to fix the width of the reinforcing fiber yarn. In the fixing step (D), the solid resin material is applied or bonded, and then the resin material is melted, and the reinforcing fiber yarn is used in a range of 2 to 20% by weight based on 100% by weight of the reinforcing fiber base material. The method for producing a reinforcing fiber base according to claim 5, wherein the reinforcing fiber base is adhered to a strip. (D) The fixing step is to apply a molten resin material and adhere to the reinforcing fiber yarn within a range of 2 to 20% by weight based on 100% by weight of the reinforcing fiber base material. The method for producing a reinforcing fiber base according to claim 5, characterized in that: In the fixing step (D), a resin material dissolved or dispersed in a solvent is applied and then the solvent is removed, and the reinforcing fiber yarn is in a range of 0.5 to 5% by weight based on 100% by weight of the reinforcing fiber base material. The method for producing a reinforcing fiber base according to any one of claims 5 to 7, wherein the reinforcing fiber base is bonded to a strip. The reinforcing fiber substrate according to any one of claims 1 to 8, wherein the reinforcing fiber substrate is a unidirectional woven fabric having at least a reinforcing fiber yarn as a warp and an auxiliary fiber yarn as a weft. Production method. The reinforcing fiber base according to claim 9, wherein the reinforcing fiber base material is a unidirectional woven fabric in which the reinforcing fiber yarns and the warp auxiliary yarns are warp yarns and the auxiliary fiber yarns are weft yarns. The method of manufacturing the material. The method for producing a reinforcing fiber base according to any one of claims 1 to 8, wherein the reinforcing fiber base is a unidirectional sheet having at least a reinforcing fiber thread as a warp. The gap between the reinforcing fiber yarns of the reinforcing fiber substrate is 0.1 to 1 mm, and the variation rate of the yarn width of the reinforcing fiber yarns is 0 to 10%. A method for producing a reinforcing fiber base according to any one of the above. The method for producing a reinforcing fiber base according to any one of claims 1 to 12, wherein a cover factor of the reinforcing fiber base is more than 80 and less than 95%. A method for producing a composite material using a reinforcing fiber substrate produced by at least the method according to any one of claims 1 to 13, wherein the composite material is subjected to the following steps (E) to (G). Material manufacturing method.
(E) a setting step of arranging a reinforcing fiber base in a mold to form a cavity;
(F) an injection step of injecting the matrix resin into the cavity to impregnate the reinforcing fiber base material with the matrix resin.
(G) a solidification step of solidifying the matrix resin to form a composite material. The setting step (E) uses either a male mold or a female mold as a molding die and a bag material, and disposes a resin diffusion medium in the cavity. The method for producing a composite material according to claim 14, wherein the matrix resin is injected while maintaining a reduced pressure.

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