JP2006328292A - Prepreg for honeycomb cocuring and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg superior in self-adhesiveness with a honeycomb and also in handling property by it while satisfying various characteristics required for skin materials, and a honeycomb laminated composite material light in weight, superior in dynamic characteristics and good in grade. <P>SOLUTION: The prepreg for honeycomb self-adhesion comprises following constituents [A], [B] and [C], and the constituent [C] is arranged on the outer surface side than [A], and the tacking property of the surface is 10 N or more. [A]: a reinforced fiber comprising continuous fiber, [B]: a matrix resin, [C]: a thermoplastic resin having voids and a continuous form, and also, the method of manufacturing the prepreg makes the leading-out tensile force of the constituent [C] 1-50 N. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-weight, high-strength and high-rigidity honeycomb laminated composite, and more particularly to a prepreg that has excellent self-adhesiveness with a honeycomb and has a tucking force that is easy to handle at the time of molding and its manufacture.

  Fiber reinforced composite materials composed of reinforced fibers and matrix resins are widely used in aircraft, automobiles, and industrial applications due to their excellent mechanical properties. In recent years, the required properties for fiber reinforced composite materials have become more and more stringent as their use results have been accumulated. In order to sufficiently bring out the mechanical properties and durability of the fiber reinforced composite material, it is important to reduce defects that lead to strength reduction. In particular, in the case of aircraft structural materials and interior materials, there are an increasing number of cases where a fiber reinforced composite material is used as a skin panel for a honeycomb sandwich panel from the viewpoint of weight reduction. As the honeycomb core of the honeycomb sandwich panel, an aramid honeycomb, a glass honeycomb, or an aluminum honeycomb is used. In the manufacture of honeycomb sandwich panels, conventionally, when bonding the prepreg and the honeycomb core, a method of sandwiching the adhesive processed into a film shape between the honeycomb core and the laminate of the prepreg, and then cocuring and bonding is used. However, as the demand for cost reduction in the field of aircraft applications has become stronger, recently prepregs are laminated on both sides of the honeycomb core and heated to simultaneously cure the prepreg and bond the prepreg and the honeycomb core. Self-adhesive honeycomb co-curing is the mainstream. In this self-adhesive honeycomb cocure molding method, it is required to increase the adhesion between the prepreg serving as the skin panel and the honeycomb core as much as possible. However, since the resin exuded from the prepreg is bonded, the resin used and the honeycomb Conventionally, it has been difficult to ensure sufficient adhesion because it is necessary to consider complex factors such as compatibility with the core.

  In response to this problem, it is disclosed that thermoplastic resin particles are blended in the matrix resin or on the prepreg surface as a method for improving the self-adhesive property by modifying the matrix of the prepreg (see, for example, Patent Documents 1 and 2). ). In general, in the self-adhesive honeycomb cocure method, the matrix resin in contact with the honeycomb is fluid-cured to form a fillet at the bonded portion between the skin and the honeycomb. However, the method disclosed in Patent Document 1 or Patent Document 2 Then, the thermoplastic resin particles flow into the fillet to make it tough and self-adhesive. However, in this method, in order to obtain sufficient self-adhesive strength, it is necessary to mix a large amount of thermoplastic resin particles in the matrix resin, and the tackiness of the prepreg is significantly lost, and the handleability during molding is reduced. In other words, there is a problem in that the mechanical properties and porosity of the molded plate are likely to occur due to adverse effects on the properties of the matrix resin. Also, at the location where the honeycomb wall and the prepreg reinforcing fiber are close to each other, the amount of resin is small, so the effect of increasing toughness is small, and if the fillet is not formed well due to factors such as molding conditions, the self-adhesive strength will be extremely low There was also a problem.

  On the other hand, as a technique for reinforcing the interlayer of fiber-reinforced composite materials that do not use a honeycomb, a technique of arranging a thermoplastic resin between the layers has been known, and as a form thereof, a film (interleaf), a fiber, a particle The thing etc. are known (for example, refer patent documents 3-5). In these methods, various thermoplastic resins are arranged on the surface of the prepreg to form a high toughness layer between the layers after molding. It is known that by increasing the toughness of the interlayer, it is possible to suppress interlayer cracks when an impact load is applied from the outside, and to increase the impact resistance of the composite material and the residual strength after impact. .

However, it has hitherto not been known to apply these various forms of thermoplastic resin layers to places other than the interlayer, for example, the skin layer of the above-mentioned honeycomb sandwich laminated composite.
US 2002/0079052 A1 Japanese Patent Publication No. 1999-002586 JP-A-1-320146 Japanese Patent No. 3387100 Japanese Unexamined Patent Publication No. 63-162732

  An object of the present invention is to provide a prepreg having excellent self-adhesiveness with a honeycomb and good handleability while satisfying various properties required for a skin material, and a method for producing the same. It is another object of the present invention to provide a honeycomb sandwich laminated composite material having excellent adhesion strength between a skin layer and a honeycomb, light weight with low internal porosity, and excellent mechanical properties.

  In order to achieve the above object, the prepreg of the present invention has the following configuration. That is, a prepreg for honeycomb self-adhesion composed of the following constituent elements [A], [B], and [C], in which the constituent element [C] is arranged on the outer surface side from [A].

[A]: Reinforcing fiber composed of continuous fibers [B]: Matrix resin [C]: Thermoplastic resin having voids and a continuous form The prepreg manufacturing method according to the present invention is a configuration for drawing from a scroll The drawing tension applied to the element [C] is 1 to 50 N.

According to the present invention, as described below, there is provided a prepreg having excellent tackiness with excellent self-adhesiveness with a honeycomb while satisfying various properties required for a skin material and good handleability during molding, and a method for producing the same. Can be provided.

  Examples of the best embodiment of the present invention will be described below.

  The element used as the constituent element [A] in the present invention is a reinforcing fiber composed of continuous fibers, and various elements can be used depending on the purpose of use of the composite material. Specific examples of the reinforcing fiber used in the present invention include carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, tungsten carbide fiber, and glass fiber. Reinforcing fibers can be used in combination of a plurality of types. Of these, carbon fiber and graphite fiber, which have good specific strength and specific elastic modulus and have a great contribution to weight reduction, are good for the present invention. Carbon fiber and graphite fiber can be used for all types of carbon fiber and graphite fiber depending on the application, but from the aspect of high tensile strength of the fiber and high impact resistance when it is a honeycomb sandwich panel, so-called High strength carbon fibers are preferred. That is, the strand tensile strength in the strand tensile test is preferably 4.4 GPa or more, and more preferably 4.6 GPa or more. Such strand tensile strength is preferably as high as possible, but about 4.9 GPa is often sufficient. Further, the tensile elongation at break is preferably 1.7% or more, and more preferably 1.8% or more. The higher the tensile elongation at break, the better. However, about 2.0% is often sufficient for the purpose of the present invention. The strand tensile test here refers to a test conducted based on JIS R7601 (1986) after impregnating a bundle of carbon fibers with a resin having the following composition and curing at 130 ° C. for 35 minutes.

* Resin composition-3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexyl-carboxylate (ERL-4221, manufactured by Union Carbide) 100 parts by weight-boron trifluoride monoethylamine (produced by Stella Chemifa Corporation) 3 Part by weight-4 parts by weight of acetone (manufactured by Wako Pure Chemical Industries, Ltd.) The reinforcing fiber preferably has a tensile modulus E of 200 GPa or more. The use of reinforcing fibers having a high tensile modulus E leads to high strength in the climbing drum peel method, which is one of the self-adhesive evaluations. The tensile modulus E is more preferably 210 GPa or more, and further preferably 220 GPa or more. The higher the tensile elastic modulus, the better. However, if it is about 230 GPa, it is often sufficient for the purpose of the present invention.

  If it exceeds 700 GPa, the resulting composite material may be brittle and impact resistance may be reduced.

  In addition, as the reinforcing fiber composed of continuous fibers used as the constituent element [A] in the present invention, carbon fibers or graphite fibers and other reinforcing fibers may be mixed and used. The shape and arrangement of the reinforcing fibers are not limited. For example, the reinforcing fibers can be used in a single direction, a random direction, a sheet shape, a mat shape, a fabric shape, and a braided shape, but a two-dimensional fabric is preferably used. be able to. In this case, the fabric structure is not particularly limited, but a fabric such as plain weave, twill weave, entangled weave, and satin weave is preferable. In particular, it is suitable in that it is easy to produce a molded product with a plain weave structure. The woven yarn of the woven fabric is composed of fiber bundles, and the number of filaments in one fiber bundle is preferably in the range of 2500 to 50000. If the number is less than 2500, the fiber arrangement tends to meander and cause a decrease in strength. On the other hand, when the number exceeds 50,000, it is difficult to impregnate the resin during prepreg production or molding. More preferably, it is the range of 2800-25000. In particular, those having 5000 or more filaments are preferred from the viewpoint of improving the surface smoothness of the honeycomb skin panel. In addition, the use of a woven fabric made of a flat carbon fiber multifilament yarn that is substantially untwisted and composed of a large number of carbon fibers makes the movement of the fabric fibers small even if the fabric prepreg is left standing for a long time. Since subsidence of the surface resin is difficult to occur, it is preferable in order to suppress a change with time in tackiness of the prepreg. In addition, since the movement of the woven fiber is small and the surface resin does not sink easily even in the prepreg being molded, it is preferable because the surface smoothness of the honeycomb sandwich panel after curing is improved. Here, “substantially no twist” means a state where there is no twist of 1 turn or more per 1 m of yarn length. In particular, it is possible to reduce the movement of the woven fiber by using a woven fabric made of a multifilament yarn having substantially no twist in the multifilament yarn and having a converging property in the range of 100 to 1000 mm, preferably 100 to 500 mm as a hook drop value. This is preferable from the viewpoints of easily maintaining the flat state of the weave yarn and suppressing the prepreg tack change with time and improving the surface smoothness of the honeycomb sandwich panel. Here, the hook drop value is a carbon fiber bundle suspended vertically in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH, and the upper and lower portions of a stainless wire having a diameter of about 1 mm and a length of about 100 mm are bent to 20 to 30 mm. It is a value expressed by the weight drop distance after 30 minutes have passed, when a 12 g weight is hung on the lower part and the upper part is hooked on the fiber bundle. This value decreases when there is twist or twist. When making a reinforced fabric using carbon fiber yarns, carbon fiber yarns are generally entangled between filaments of a precursor fiber bundle in order to prevent process troubles due to winding of broken filaments around rollers in the production process. Is imparted with convergence. In addition, the carbon fiber yarn is given convergence by the adhesion amount of the sizing agent and the adhesion between the filaments. Convergence is controlled by the degree of entanglement between filaments, the amount of sizing agent attached, and the degree of adhesion between filaments. If the hook drop value is 100 mm or less and the convergence is too strong, it may be difficult to increase the cover factor of the above-mentioned fabric prepreg. In this case, the change with time of the tack property of the prepreg may become large, and the resin impregnation property of the prepreg may be extremely inferior. As a result, surface pits and porosity (internal voids) of the skin panel are likely to occur. When the hook drop value is 1000 mm or more, the converging property of the carbon fiber yarn is deteriorated, fluff is easily generated, and the weaving property is deteriorated, and the strength as a composite material is reduced.

  In particular, when a woven fabric is used as the component [A] in the present invention, a woven fabric having a cover factor of 95% or more is preferable. Here, the cover factor is the ratio of the area where the woven yarn portion exists to the total area of the prepreg. That is, when a region having an area S1 is set on the woven fabric, Cf = [(S1− C2 obtained by S2) / S1] × 100 is obtained at any 10 locations, and the simple average is defined as the cover factor Kc. As the cover factor Kc is larger, the opening, widening and flattening of the woven yarn is progressing, and the texture is smaller. By using a woven fabric prepreg having a cover factor of 95% or more as a skin panel, the skin panel having excellent rigidity and strength can be obtained because the porosity inside the skin panel is small. Further, by using a woven prepreg having a cover factor of 95% or more as a skin panel, a honeycomb sandwich panel having excellent self-adhesion between the skin panel and the honeycomb core can be obtained. In addition, by using a woven prepreg with a cover factor of 95% or more as a skin panel, the woven fabric is uniformly spread, so that a honeycomb sandwich panel with good surface smoothness of the skin panel can be obtained, and the resin is applied to the prepreg surface. Therefore, the change with time of tack of the prepreg is reduced.

  Also, if the cover factor is large, the burn-through characteristics are excellent. Here, the burn-through property is an effect of preventing the penetration of a flame in the event of an important fire when used as an interior material, that is, a molded plate having good fire resistance can be obtained. When the cover factor is insufficient, pits may occur on the surface of the skin panel of the molded body, and porosity may be generated inside the skin panel, and the climbing drum peel strength may be reduced. Further, when the cover factor is insufficient, the prepreg may have a decrease in tackiness and a change with time. A particularly preferable cover factor range for the present invention is 97.5% or more.

Moreover, when using the reinforced fiber fabric which consists of continuous fibers as component [A] for this invention, it is preferable that the fabric weight of a reinforced fiber fabric is 150-550 g / m < ² >. Thereby, a skin panel having excellent mechanical strength can be obtained. If the basis weight of the reinforcing fiber fabric is less than 150 g / m ² , the mechanical strength may be insufficient, and if it exceeds 550 g / m ² , workability during layup may be impaired. The basis weight of the reinforcing fiber fabric is more preferably 170 to 500 g / m ² . Further, if the weight fraction of the reinforcing fiber fabric is less than 40% by weight, the resulting fiber-reinforced composite material skin panel may have insufficient rigidity, and if it exceeds 85% by weight, voids are formed in the resulting skin panel. May be more likely to occur.

  The matrix resin used as the component [B] in the present invention is preferably a thermosetting resin having a minimum viscosity during molding of 0.1 to 1000 Pa · s. If it is less than 0.1 Pa · s, the resin may flow during the curing of the prepreg, and a sandwich panel having a desired fiber content may not be obtained, or a core crash may occur. On the other hand, if it is greater than 1000 Pa · s, the fluidity of the resin is low, and the fillet formation in the obtained sandwich panel may be insufficient. Here, the fillet refers to a portion cured from the prepreg laminate in the thickness direction of the honeycomb core along with the resin dripping or rising. The minimum viscosity of the matrix resin is more preferably 0.5 to 100 Pa · s, and further preferably 0.5 to 50 Pa · s.

  As the matrix resin used as the component [B] in the present invention, a resin that is cured by heat or external energy such as light or electron beam and at least partially forms a three-dimensional cured product is used as a main component. In particular, so-called thermosetting resins that are cured by heat are preferably used. As the thermosetting resin, an epoxy resin, a phenol resin, a vinyl ester resin, a benzoxazine resin, a cyanate ester resin, a bismaleimide resin or the like is preferably used, and a mixture of two or more of these may be used. Among these, an epoxy resin that is easy to mold and excellent in physical properties is preferably used.

  When an epoxy resin is used as the matrix resin used as the component [B] in the present invention, it is important that the epoxy resin composition contains at least an epoxy group-containing compound and a curing agent. As such an epoxy group-containing compound, a compound having at least two epoxy groups in the molecule is preferably used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol type epoxy resin such as tetrabromobisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, etc. Novolak-type epoxy resin, tetraglycidyl diaminodiphenylmethane, triglycidylaminophenol, tetraglycidylxylenediamine, glycidylamine-type epoxy resin such as glycidylaniline, glycidyl o-toluidine, oxazolidone ring-containing epoxy resin, etc. Preferably used. Examples of the curing agent used in the epoxy resin composition include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines such as triethylenetetramine and isophoronediamine, dicyandiamide, tetramethylguanidine, and methylhexahydro. Carboxylic anhydride such as phthalic anhydride, carboxylic acid hydrazide such as adipic acid hydrazide, carboxylic acid amide, polyphenol compound, polymercaptan, Lewis acid complex such as boron trifluoride ethylamine complex, or a combination thereof is preferable. Used. Among these, it is preferable that each structural isomer of diaminodiphenylsulfone and / or dicyandiamide is included in order to give good heat resistance and curability. Such a curing agent is preferably blended in an amount of 1 to 70 parts by weight with respect to 100 parts by weight of the total epoxy group-containing compound in the epoxy resin composition from the viewpoint of achieving both the life and curability of the resulting prepreg. More preferably, it is part by weight. When each structural isomer of diaminodiphenylsulfone and / or dicyandiamide is contained, the blending amount of each structural isomer of diaminodiphenylsulfone is 15 to 15 parts by weight based on 100 parts by weight of the epoxy group-containing compound in the epoxy resin composition. 70 parts by weight is blended, and dicyandiamide is compatible with the life and curability of the prepreg obtained by blending 2 to 15 parts by weight with respect to 100 parts by weight of the epoxy group-containing compound in the epoxy resin composition. Good heat resistance.

  Further, when an epoxy resin composition is used as the matrix resin used as the constituent element [B], an epoxy resin composition containing at least one selected from a rubber component, a thermoplastic resin, a thixotropic agent, a urea compound, and imidazoles. It is preferable that it is a thing. Thereby, the fluidity | liquidity of an epoxy resin composition can be controlled and a preferable minimum viscosity can be implement | achieved. As such a rubber component, solid rubber, liquid rubber, rubber particles, or the like can be used. In general, solid rubber has a large viscosity increase when the same amount is dissolved in epoxy resin compared to liquid rubber, and it can maintain the heat resistance of the molded product relatively while maintaining the resin composition in the molding process at an appropriate viscosity level. preferable. In particular, the temperature dependence of the viscoelastic function of the resin composition is reduced, the handling property such as tackiness is not easily deteriorated even if the working environment temperature for handling the prepreg is changed, and the prepreg is left at room temperature or the like. The change in tackiness with time can be reduced, and the surface smoothness of the skin panel as a cured product can be improved.

  As the solid rubber, an acrylonitrile-butadiene copolymer which is a random copolymer of butadiene and acrylonitrile is preferable from the viewpoint of compatibility with the epoxy resin. The compatibility with the epoxy resin can be controlled by changing the copolymerization ratio of acrylonitrile. Further, a solid rubber having a functional group is more preferable in order to increase the adhesion with the epoxy resin. Examples of the functional group include a carboxyl group and an amino group. In particular, a solid acrylonitrile-butadiene rubber containing a carboxyl group is preferable. Hydrogenated nitrile rubber is also preferable because of its excellent weather resistance. NIPOL (registered trademark) 1072, NIPOL 1072J, NIPOL 1472, NIPOL 1472HV, NIPOL 1042, NIPOL 1043, NIPOL DN631, NIPOL 1001, ZETPOL (registered trademark) 2020, ZETPOL 2210, ZETPOL 2210, ZETPOL3110, ZETPOL3110, ZETPOL3110 Is mentioned.

  As the rubber particles, crosslinked rubber particles and core-shell rubber particles obtained by graft polymerization of a different polymer on the surface of the crosslinked rubber particles are preferably used. Commercially available crosslinked rubber particles include XER-91 (model number, manufactured by Nippon Synthetic Rubber Industry Co., Ltd.) made of a crosslinked product of carboxyl-modified butadiene-acrylonitrile copolymer, and CX-MN series (model number, made of acrylic rubber fine particles). Nippon Shokubai Co., Ltd.), YR-500 series (model number, manufactured by Toto Kasei Co., Ltd.) and the like can be used. Commercially available core-shell rubber particles include paraloid (registered trademark) EXL-2655 (manufactured by Kureha Chemical Industry Co., Ltd.), acrylate ester / methacrylate ester copolymer comprising butadiene / alkyl methacrylate / styrene copolymer. STAPHYLOID (registered trademark) AC-3355, TR-2122 (model number, manufactured by Takeda Pharmaceutical Co., Ltd.), PARALOID (registered trademark) EXL-2611, EXL- composed of butyl acrylate / methyl methacrylate copolymer 3387 (model number, manufactured by Rohm & Haas) or the like can be used.

  While these rubber components tend to improve toughness, they tend to lower the elastic modulus and heat resistance of the resin. Therefore, when blended, the addition amount is preferably 0.1 to 10% by weight based on the entire epoxy resin composition, More preferably, it is 2 to 6% by weight.

  In addition, such a thermoplastic resin has a carbon-carbon bond, amide bond, imide bond, ester bond, ether bond, carbonate bond, urethane bond, urea bond, thioether bond, sulfone bond, imidazole bond, carbonyl bond in the main chain. A thermoplastic resin having a bond selected from is preferably used. A group of thermoplastic resins belonging to engineering plastics such as polyacrylates, polyamides, polyaramids, polyesters, polycarbonates, polyphenylene sulfides, polybenzimidazoles, polyimides, polyetherimides, polysulfones, polyethersulfones are more preferably used. Particularly preferably, polyimide, polyetherimide, polysulfone, polyethersulfone and the like are preferably used because of their excellent heat resistance.

  Moreover, it is preferable that these thermoplastic resins have reactivity with the thermosetting resin from the viewpoint of improving toughness and maintaining the environmental resistance of the cured resin. Particularly preferred functional groups include a carboxyl group, an amino group, and a hydroxyl group. The blending amount of the thermoplastic resin is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the total epoxy group-containing compound in the epoxy resin composition, and gives appropriate fluidity to the epoxy resin composition, The resulting carbon fiber reinforced plastic may have an effect of increasing the mechanical strength.

Examples of the thixotropic agent include inorganic particles such as talc, aluminum silicate, particulate silica, calcium carbonate, mica, montmorillonite, smectite, carbon black, silicon carbide, and alumina hydrate. Among them, fine-particle silica is known to have a thixotropic effect when added to a resin composition, but it also reduces the temperature dependence of the viscoelastic function of the resin composition and handles prepregs. Handleability is unlikely to deteriorate even when the working environment temperature fluctuates. Also, the time-dependent change in tackiness caused by leaving the prepreg is reduced, improving the surface smoothness of the cured skin panel and self-adhesion to the honeycomb core. This is preferable because it provides an excellent effect. As fine particle silica having silicon dioxide as a basic skeleton, for example, those having an average primary particle size in the range of 5 to 40 nm are commercially available under the trademark Aerosil (manufactured by Nippon Aerosil Co., Ltd.). It is preferable that the primary particle diameter is as fine as 40 nm or less in order to give a sufficient thickening effect. The particle diameter is evaluated with an electron microscope. The specific surface area is preferably in the range of 50 to 400 m ² / g. In general, silica whose silica surface is covered with silanol groups is used. However, it is important to use hydrophobic fine-particle silica in which the hydrogen of the silanol group is substituted with methyl group, octyl group, dimethylsiloxane, etc. It is more preferable from the viewpoints of effect, stability of thixotropy and improvement of mechanical properties represented by water resistance and compression strength of the molded product. When mix | blending this thixotropic agent, it is preferable to add in 0.1-8 weight% with respect to the whole epoxy resin composition. If it is less than 0.1% by weight, pits and resin fading tend to occur on the skin panel surface of the honeycomb sandwich panel. On the other hand, if it exceeds 8% by weight, the resin viscosity is too high and impregnation into the reinforcing fibers tends to be difficult. A more preferable addition amount is in the range of 0.2 to 5% by weight, and further preferably in the range of 0.3 to 3% by weight.

  The thermoplastic resin, rubber component and thixotropic agent may be used alone, but when the thermoplastic resin and thixotropic agent or the rubber component and thixotropic agent are used in combination, the pits on the skin panel surface are reduced. It is more preferable for improving the tackiness of the prepreg, suppressing the change with time and maintaining the heat resistance of the molded product. The most preferable addition amount in that case is 5 to 25% by weight of the thermoplastic resin and 0.3 to 3% by weight of the thixotropic agent based on the whole epoxy resin composition when the thermoplastic resin and the thixotropic agent are used in combination. Yes, when the rubber component and the thixotropic agent are used in combination, the rubber component ranges from 2 to 4% by weight and the thixotropic agent from 0.3 to 3% by weight.

  Such urea compounds include 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4-methylphenyl). ) -1,1-dimethylurea, 2,4-bis (3,3-dimethylureido) toluene and other compounds obtained by the reaction of a secondary amine and isocyanate are preferably used. The compounding amount of the urea compound is preferably 0 to 10% by weight based on 100% by weight of the total epoxy resin in the epoxy resin composition, while providing appropriate fluidity to the epoxy resin composition and excellent. This is preferable because it imparts high curability.

  As such imidazoles, 2-ethyl-4-methylimidazole, 2,4-dimethylimidazole, 2-phenylimidazole and the like can be suitably used. The amount of the urea compound is preferably 0 to 7 parts by weight based on 100 parts by weight of the total epoxy resin in the epoxy resin composition. Since life is excellent, it is preferable.

  The epoxy resin composition as the matrix resin used as the component [B] of the present invention has a rubber component, a thermoplastic resin, a rocking agent because it has an appropriate fluidity and provides excellent curability and pot life. More preferably, it contains at least two selected from a modification-imparting agent, a urea compound, and imidazoles. This combination preferably contains a thermoplastic resin and a urea compound. At this time, it is particularly preferable that the total amount of the thermoplastic resin and the urea compound is 1 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin composition because particularly excellent fluidity and curability are given. Furthermore, arbitrary components, such as a high molecular compound and organic particle other than the above, can be mix | blended with this epoxy resin composition according to each objective. As the polymer compound, a thermoplastic elastomer can be added. In particular, a polyester-based or polyamide-based thermoplastic elastomer is preferably blended. An epoxy resin composition containing a polyester-based or polyamide-based thermoplastic elastomer has excellent tackiness, has low viscosity, and is excellent in drape and impregnation into reinforcing fibers. Further, compared to the case where such a thermoplastic elastomer is not blended, the temperature dependence of the viscoelastic function of the resin, particularly the change near room temperature is small, and therefore the temperature dependence of the handling property of the prepreg becomes small, which is preferable. . Therefore, a prepreg using the same can exhibit excellent characteristics in tackiness, draping property, surface quality of the obtained sandwich panel, and the like. In order to obtain such an effect, it is preferable to blend 1 to 20 parts by weight of a polyester or polyamide elastomer with respect to 100 parts by weight of the thermosetting resin. The melting point of the polyester-based or polyamide-based thermoplastic elastomer is preferably 100 ° C. or higher and more preferably 140 ° C. or higher because it affects the heat resistance of the thermosetting resin composition after curing. As the thermoplastic resin particles, polyamide or polyimide particles are preferably used. The effect of improving the adhesive strength between the skin panel / honeycomb core of the sandwich panel obtained by blending these thermoplastic resin particles, and further imparting a high degree of impact resistance to the skin panel. As commercially available polyamide particles, SP-500 (model number, manufactured by Toray Industries, Inc.), orgasol (registered trademark, manufactured by ATOCHEM) and the like can be preferably used. The thermoplastic resin particles preferably have an average primary particle diameter in the range of 1 to 50 μm. When the average primary particle size is less than 1 μm, the effect of improving the adhesive strength between the skin panel and the honeycomb core is reduced. When the average primary particle size is more than 50 μm, the arrangement of the reinforcing fibers may be disturbed, resulting in a decrease in strength or poor impregnation. More preferably, the average primary particle diameter is in the range of 1 to 30 μm. In addition, when blending these particles, 1 to 18% by weight, preferably 2 to 10%, based on the entire epoxy resin composition, in order to improve the adhesive strength and not cause a decrease in strength due to disorder of the reinforcing fiber arrangement. It is preferable to blend by weight%.

  The component [C] is a thermoplastic resin having a void and a continuous form, and is disposed on the outer surface side of the component [A] that is a reinforcing fiber. Here, having a void means that the matrix resin can flow and pass through the constituent element [C]. As a result, the resin moves from the component [A] side of the prepreg through the component [C] to the honeycomb side to form a fillet. If there are no voids, the fluidity of the resin is reduced and the resin cannot sufficiently wet the honeycomb wall, and fillet formation in the resulting sandwich panel may be insufficient, especially the tool side skin panel and the honeycomb core. Adhesive strength with is likely to be insufficient.

  In addition, since the constituent element [C] does not cover the entire surface due to the voids, the matrix resin can be easily passed and impregnated even during the preparation of the prepreg, and has excellent handling properties such as tackiness and drapeability. Prepreg. Furthermore, since the constituent element [C] having voids has a function of holding a certain amount of resin on the surface of the prepreg, the adjustment range of the tackiness is larger than that of a normal prepreg, and the change in the tackiness with time is extremely small. Has the effect of reducing. The continuous form means a form that is continuous in the in-plane direction such as a net or random. When the component [C] has a continuous form, even if the component [B] flows during molding, the surface density of the component [C], that is, the weight per unit area (hereinafter referred to as basis weight) is maintained. As a result, even when the matrix resin [B] is eliminated by the contact pressure at the contact portion between the honeycomb wall and the prepreg component [A], the component [C] can be disposed at a very high concentration in the contact portion. it can. Thereby, the adhesive strength between the skin panel and the honeycomb core is enhanced. When the constituent element [C] does not have a continuous form such as a particulate form, the constituent element [C] is dissipated during the flow of the resin, and the contact portion is not sufficiently strengthened. The continuity of the constituent element [C] may be partially lost due to the presence of a seam or the like as long as the above effects are not impaired, but at least from the viewpoint of effectively expressing the effects shown above. It must be continuous in a range larger than the size of the honeycomb cells used.

  The constituent element [C] is preferably a continuous form and a random form. The random form means that a configuration in which the same structure is repeated at a constant period (for example, a parallel arrangement of monofilaments or multifilaments, or a regular fabric structure such as a woven fabric, a knitted fabric, or a braid) is not taken. Thereby, the in-plane shear deformation of the component [C] is restricted, and the basis weight retention is increased. Moreover, such a form can be realized by simple spraying or spraying, and does not require a special device such as a loom as in the case of producing a regular fabric. Such a form can be most suitably realized by using a long-fiber nonwoven fabric. Compared to woven fabrics and mats, long fiber nonwoven fabrics are superior in productivity in that a fabric can be obtained directly from a resin without making the raw material resin into a filament once.

  The component [C] is disposed on the outer surface side of the component [A] in the prepreg of the present invention. In this way, when the prepreg is brought into contact with the honeycomb, the component [A] is surely disposed between the honeycomb and the honeycomb, and when the skin material is peeled off from the cured honeycomb laminate, cracks are generated in the component [ C] prevents self-adhesion.

  The component [C] may be arranged on only one side or both on the two outer surfaces of the front and back surfaces of the prepreg. If arranged on one side, the component [C] disposed unnecessarily other than the core contact surface is reduced, which is efficient. On the other hand, when arranged on both sides, the component [C] is surely arranged on the honeycomb contact surface without paying special attention to the distinction between the front and back of the prepreg at the time of lamination. Manufacturing cost can be reduced.

  The material of the component [C] is a thermoplastic resin. Typical examples of the thermoplastic resin in the main chain include carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfone bonds, imidazole bonds, and carbonyl bonds. is there. In particular, polyamide, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polyaramid, and polybenzimidazole are excellent in toughness. It is suitable because self-adhesion can be increased. Among these, polyamide, polyacetal, polyphenylene oxide, polyimide, polyetherimide, polyethersulfone, polyetherketone, and polyaramid are suitable for the present invention because of high toughness and good heat resistance. The toughness of polyamide is particularly excellent, and heat resistance can be achieved by using a material belonging to amorphous transparent nylon. Among polyamides, nylon 12 is particularly preferred because it has features such that it is easy to obtain a desired shape and configuration, has very high toughness, and has little deterioration in properties due to water absorption. As the constituent element [C], a plurality of types of thermoplastic resin long fibers can be used in combination, or a plurality of types of thermoplastic resins can be used in combination. These methods are preferable because the characteristics of the composite material can be improved by optimizing the combination of materials.

  The elastic modulus and yield strength of the material of the component [C] are preferably lower than the elastic modulus and yield strength of the resin cured product of the component [B] because they are effective as a crack resistance material when peeling the skin panel. However, on the other hand, when the elastic modulus of the material of the component [C] is as low as that of an elastomer, it easily deforms due to changes in conditions such as pressure, temperature or heating rate during molding of the composite material, and the thickness between the laminates varies. As a result, the physical properties of the composite material become unstable. Therefore, in order to obtain stable high toughness insensitive to changes in molding conditions, it is preferable that the flexural modulus in the bulk of the component [C] is in the range of 0.8 to 4 GPa. Moreover, it is also preferable for the reason similar to the above that the tensile elastic modulus when the component [C] is fibrous is in the range of 0.4 to 50 GPa. In particular, when the component [B] is used for the purpose of strengthening the interlayer of the composite material with the component [C] having high elongation at break and high toughness, while utilizing the rigidity of the component [B] for the expression of the compressive strength of the composite material. Rather, the lower range of 2 to 20% by weight is more preferable, and the range of 4 to 13% by weight is more preferable.

  Further, the prepreg having the above-described configuration needs to have a surface tack force of 10 N or more immediately after production, and preferably 13 N or more. Further, it is preferable that the surface tack force after being left for 20 days in an environment of 24 ° C. and humidity 50% is 10 N or more.

  Here, the tack force is set to 30 mm / 30 mm by leaving the prepreg in an atmosphere at a temperature of 24 ± 2 ° C. and a humidity of 50 ± 5% for 30 minutes, and using a tack tester or the like to press the cover glass onto the prepreg with a load of 4 N for 5 seconds. It is evaluated as a resistance force at the time of pulling and peeling at a speed of minutes.

  The prepreg for honeycomb self-adhesion is often used in a part having a small curvature or a part having a complicated shape in practical use, and tack force is important in handling. In particular, when molding a member of a large aircraft or the like, it is stored in a frozen state after being wound in a roll and sealed with a polyethylene bag or the like. When using the prepreg, the stacking operation is performed after thawing and cutting into a predetermined shape in a room temperature environment. Since the stacking operation may take 10 days or more, the room temperature environment is maintained for 10 days or more after cutting into a predetermined shape. May be left unattended. In that case, it is desired that the lamination workability is not impaired. If the surface tack force of the prepreg is less than 10 N, the laminating workability may be impaired, which is not preferable.

  Moreover, in the drapability of the prepreg, it is preferably 50 N or less, more preferably 40 N or less. When it is larger than 50N, it is not preferable because it is inferior in shape followability and moldability at the time of lamination work.

  Hereinafter, the drape property measuring method in the present invention will be described. A strip-shaped sample having a length of 200 mm and a width of 100 mm is cut so that the fiber direction is 45 ° from a cross prepreg having a width of 1000 mm. Insert a marking line at a position 20 mm from the center line in the width direction and both ends in the length direction of the sample, fix the support tool to the scratched part at both ends in the length direction, and attach the support tool to the tensile tester. Then, the support is pulled at a pulling speed of 100 mm / min in an environment of 24 ° C. and 50% RH, the load at that time is recorded on the chart, and the value when the strain is 10% is read. As a testing machine, an appropriate material testing machine of a type that can keep the crosshead moving speed constant without a load measurement error exceeding ± 1% is used.

As a method for manufacturing the prepreg having the above-described configuration, the following method can be used.
[Method 1]
The component [C] is pasted on the surface of the component [B] formed into a film by applying to a support such as a release paper, and then bonded to the component [A], using a heat roll or the like. By applying heat and pressure, the component [A] and [C] are impregnated with the component [B] to form a prepreg.
[Method 2]
A prepreg is formed by randomly disposing the constituent element [C] on the surface of the constituent element [A] impregnated with the constituent element [B]. If this is the case, the component [C] remains exposed on the surface of the prepreg, and the tack force becomes insufficient. Therefore, the component [C] is impregnated with the component [B] by heating and pressing using a heat roll or the like. It is desirable to make it. As a modification of this method, the component [C] is impregnated with the component [B], the component [C] is randomly arranged on the surface, and then applied onto a release paper or the like. [B] may be bonded and impregnated by heating and pressing.
[Method 3]
A prepreg is formed by randomly disposing the constituent element [C] on the constituent element [A] in a plane and then impregnating the constituent element [B].
[Method 4]
A prepreg is formed by laminating the component [C] on the component [A] impregnated with the component [B]. In this case, since the component [C] is exposed on the prepreg surface as it is, the tackiness may be insufficient. After bonding, the component [C] is heated and pressurized using a heat roll or the like, and the component [C] C] is preferably impregnated with component [B]. As this method, the component [C] may be impregnated with the component [B] in advance.
[Method 5]
By applying the component [B], the component [C], and the component [A], which are formed into a film by applying to a prepreg support such as a release paper, in any order or simultaneously in random order and heating and pressing. A prepreg is formed. In this case, if the positional relationship of superposition is such that the constituent element [C] is sandwiched between the constituent element [A] and the constituent element [B] formed into a film shape, the constituent element [C] has the constituent element [B]. ] Is preferable because it is easy to be impregnated.
It is possible to produce the prepreg of the present invention using any of the above-described methods, but [Method 1] is advantageous in terms of stable supply of component [C] (decrease in basis weight variation) and simplicity of production equipment. preferable.

  In any of the above-described methods, it is necessary to continuously supply the component [C] when continuously producing the prepreg. As described above, from the viewpoint of cost and production efficiency, it is preferable to use a long-fiber non-woven fabric (hereinafter referred to as non-woven fabric) as the component [C]. In general, the nonwoven fabric is preferably used in the form of a roll wound around a core such as a paper tube, but the pulling tension applied to the nonwoven fabric when pulled out from the roll-shaped roll is 1 to 50 N / m with respect to the width of the nonwoven fabric. It is preferable that it is 5 to 40 N / m. When the tension is lower than 1N, the nonwoven fabric is supplied in a wrinkled state and not only the quality is lowered, but also the mechanical properties of the molded product are lowered. In addition, if it exceeds 50 N / m, the nonwoven fabric is stretched in the traveling direction and cannot be shrunk in the width direction to cover the surface of the prepreg, so that the quality is lowered or the predetermined basis weight cannot be obtained. It leads to the deterioration of mechanical properties.

  Moreover, in the manufacturing method mentioned above, in order to make component [B] impregnate component [A], it is preferable that the temperature to heat is 50-150 degreeC, More preferably, it is 100-120 degreeC. When the heating temperature at this time is less than 50 ° C., the component [B] cannot be impregnated into the component [A], the release paper cannot be peeled from the prepreg, and the porosity of the molded product may increase. Not only does the quality deteriorate, but it also leads to a decrease in the mechanical properties of the molded product. Further, when the heating temperature exceeds 150 ° C. or higher, the component [B] may be excessively impregnated in the component [A], so that the amount of resin on the surface of the prepreg is reduced and appropriate surface tackiness cannot be obtained. This is not preferable because the prepreg is hard and drapeability is poor.

  Moreover, in the manufacturing method described above, in order to impregnate the component [B] into the component [A], it is preferable to pressurize a linear pressure of 1 to 100 N simultaneously with heating, more preferably 15 to 75 N. is there. When the linear pressure at this time is less than 1 N, the component [B] cannot be impregnated into the component [A], and the support such as release paper cannot be peeled off from the prepreg, or the porosity of the molded product increases. Not only lowers the quality but also lowers the mechanical properties of the molded product. In addition, when the linear pressure exceeds 100 N, the component [B] may be excessively impregnated into the component [A], so that the amount of resin on the prepreg surface is reduced and an appropriate surface tack force cannot be obtained, and at the same time, the prepreg is hard Since drapeability is inferior, it is not preferable.

  Moreover, arbitrary cover films, such as a product made from polyethylene, can be affixed to a prepreg product. When pasting the cover film, it is necessary to peel off at least the support such as the release paper on one side, but it is possible to attach the cover film on the one side of the prepreg support such as the release paper immediately after peeling from the prepreg. It is preferable from the viewpoint of maintaining tackiness. Here, the term “immediately after” means about 30 seconds to 1 minute, and does not exceed 1 minute at the longest. Although it is not necessary to be within a few seconds after peeling of the prepreg support at least, the shorter the time, the better the tack force on the prepreg surface can be maintained.

  In the honeycomb laminated composite material of the present invention, the prepreg of the present invention is laminated in direct contact with the honeycomb material on at least one surface, and the component [B] using means such as heat and light while applying pressure to the contact portion. It can be formed by a cocure method in which it is bonded to the honeycomb core while curing. As a method of curing the matrix resin of the prepreg while applying pressure to the contact portion between the prepreg and the honeycomb, vacuum bag molding, autoclave molding using a vacuum bag, press molding, and the like can be used. Autoclave molding is preferred to obtain a high performance honeycomb sandwich panel.

  In this honeycomb laminated composite material, the component [B] is cured to become a matrix resin cured product of the skin panel. The component [C] is disposed between the honeycomb and the component [A] adjacent to the honeycomb, and when the skin panel is peeled off, the crack is prevented from progressing by the tough component [C]. High self-adhesiveness is expressed. The honeycomb laminated material thus obtained has a high self-adhesiveness corresponding to a climbing drum peel torque measured in accordance with ASTM D1781 of preferably 33 N · m / m or more, more preferably 35 N · m / m or more. be able to.

  Hereinafter, the present invention will be described more specifically with reference to examples. About each Example and the comparative example, preparation of a prepreg, preparation of a composite material etc., and the measurement of various physical properties were performed by the method shown next. The contents of Examples and Comparative Examples are summarized in Table 1.

1. Preparation of Prepreg The resin composition shown in Table 1 (the numbers in the table represent parts by weight) was coated on release paper using a reverse roll coater to prepare a resin film having a predetermined resin basis weight. A prepreg was prepared by laminating a non-woven fabric on the surface of the resin film so that the non-woven fabric was placed on both sides of the reinforcing fiber woven fabric and impregnating the resin composition while heating and pressing using a heat roll. Reinforcing fiber fabric is manufactured by Toray Industries, Inc., carbon fiber “Torayca (registered trademark)” T700GC-12K (12,000 fibers, tensile strength 4.9 GPa, tensile elastic modulus 240 GPa, tensile elongation 2.1%) The plain woven fabric CF6273H (cover factor 99.7%, fiber basis weight 193 g / m ² ) was used.

2. Measurement of Unimpregnation Rate First, a 100 mm square sample was cut out so as to be uniform in the width direction of a 1000 mm width woven prepreg, and three measurement samples were obtained. The sample is fixed to the slide with a double-sided tape, and the warp cross section is observed with a reflection optical microscope and photographed at a magnification of 25 times as a black and white photograph. At this time, the impregnated portion of the prepreg cross section is photographed bright and the non-impregnated portion is photographed dark. Next, the photographed black and white photograph is divided into a light color part and a dark color part and binarized. There are various binarization methods. For example, the following method can be used. Capture black and white photos at a resolution of 200 using a scanner connected to a computer. Although it does not specifically limit as a scanner, For example, GT-7000S by EPSON company etc. can be used.

A photographic image histogram is displayed on the image processing software using the image processing software, a level 100 portion of the histogram is used as a binarization boundary, a dark color portion (level 100 or lower) is an unimpregnated portion, a light color portion (level) of the prepreg cross section. 101 or more) is used as the impregnated portion of the prepreg cross section, and the unimpregnated ratio is calculated from the area ratio of both by the following equation.
Non-impregnation rate (%) = (dark color area of histogram / total area of histogram) × 100
As image processing software, this time Adobe Systems, Inc. Adobe Photoshop was used. The case where the non-impregnation rate is 0 to 30% is evaluated as ◯, the case where 31 to 60% is included, and the case where 61% or more is determined as ×.

3. Measurement of tack force The prepreg is allowed to stand for 30 minutes in an atmosphere having a temperature of 24 ± 2 ° C. and a humidity of 50 ± 5%.
Using a PICMA tack tester II manufactured by Toyo Seiki Seisakusho Co., Ltd., a 18 × 18 mm ² cover glass is pressure-bonded to the prepreg with a load of 4 N for 5 seconds, and the resistance force when it is pulled and peeled at a speed of 30 mm / min is a tack force. As evaluated.

4). Measurement of Drapability A strip-shaped sample having a length of 200 mm and a width of 100 mm is cut from a cross prepreg having a width of 1000 mm so that the fiber direction is 45 °. Insert a marking line at a position 20 mm from the center line in the width direction and both ends in the length direction of the sample, fix the support tool to the scratched part at both ends in the length direction, and attach the support tool to the tensile tester. Then, the support is pulled at a pulling speed of 100 mm / min in an environment of 24 ° C. and 50% RH, the load at that time is recorded on the chart, and the value when the strain is 10% is read. As a testing machine, an appropriate material testing machine of a type that can keep the crosshead moving speed constant without a load measurement error exceeding ± 1% is used. The measurement was performed using a Tensilon UTM-4L universal tensile tester manufactured by Toyo Seiki Co., Ltd.

5. Production of Sandwich Panel (1) Lamination of Samples Nomex Honeycomb SAH1 / 8-8.0 (manufactured by Showa Aircraft Co., Ltd., model number: SAH1 / 8-8.0, thickness 12.7 mm) was used as the honeycomb core. . The prepreg is the above-described woven prepreg and has a two-ply symmetrical laminated structure (± 45 °) / (0 ° / 90 °) on the top and bottom of the honeycomb core (the outermost layer is ± 45 ° with respect to the honeycomb core). did. Here, the dimensions of the honeycomb core and the prepreg are 40 cm (short direction) × 50 cm (longitudinal direction), and the prepreg is laminated so that the short direction is the ribbon (L) direction of the honeycomb core and the warp direction of the prepreg. did.

(2) Molding of sample The following procedures (a) to (d) were performed.
(A) The green body in which the prepreg is laminated on the honeycomb core is placed on an aluminum tool plate coated with a release agent, for example, Fricoat (registered trademark) 44-NC (manufactured by THE DEXTER CORPORATION).
(B) After the green body is covered with a nylon film, the inside of the nylon film (hereinafter abbreviated as “inside of the system”) is kept in a vacuum state, and then placed in an autoclave as it is.
(C) The pressure in the autoclave is increased to 0.15 MPa, then the pressure in the system is returned to normal pressure, and then the pressure in the autoclave is increased to 0.30 MPa, and then the temperature rise is started.
(D) The pressure in the autoclave is kept at 0.30 MPa until molding is completed, the temperature is raised to 180 ° C. at 1.5 ° C./min, and then left at 180 ° C. for 2 hours to cure the resin. After being bonded to the honeycomb core, the temperature is lowered to room temperature at 2 ° C./min to obtain a honeycomb cocure molded body, that is, a honeycomb sandwich panel.
6). Measuring the amount of porosity After cutting the center of the skin material of the honeycomb molded article with a diamond cutter and polishing the cut surface with sandpaper, the polished surface is spread over the entire cut surface with an optical microscope (Nikon ( Using a microscope MM-20), the photograph was taken at a magnification of 25 times. The percentage content of the area occupied by the porosity in the photograph with respect to the cross-sectional area of the cut surface of the skin material was defined as the porosity content. The area measurement is not particularly limited as long as it can be performed with high accuracy, but the captured black-and-white photograph is binarized by dividing it into a light color part and a dark color part. There are various binarization methods. For example, the following method can be used. Capture black and white photos at a resolution of 200 using a scanner connected to a computer. Although it does not specifically limit as a scanner, This time GT-7000S by EPSON company etc. were used.

A photographic image histogram is displayed on the image processing software using the image processing software, a level 100 portion of the histogram is used as a binarization boundary, a dark color portion (level 100 or lower) is an unimpregnated portion, a light color portion (level) of the prepreg cross section. 101 or more) is used as the impregnated portion of the prepreg cross section, and the unimpregnated ratio is calculated from the area ratio of both by the following equation.
Porosity content rate (%) = (Histogram dark area / histogram total area) × 100
As an image processing software, this time Adobe Systems, Inc. An Adobe Photoshop or the like was used.
Example 1
The following raw materials were kneaded to prepare a matrix resin composition.
(1) Tetraglycidyldiaminodiphenylmethane ("Sumiepoxy" ELM434, manufactured by Sumitomo Chemical Co., Ltd.) 40 parts by weight (2) Liquid bisphenol A type epoxy resin ("Epicoat" 828, manufactured by Japan Epoxy Resin Co., Ltd.) 30 parts by weight (3) Oxazolidone ring-containing epoxy resin (AER4152, manufactured by Asahi Kasei Epoxy Corporation) 30 parts by weight
(4) 4,4′-diaminodiphenylsulfone (SumiCure S, manufactured by Sumitomo Chemical Co., Ltd.) 34.8 parts by weight (5) Solid rubber (Nipol 1072, manufactured by Nippon Zeon Co., Ltd.) 4 parts by weight This matrix resin composition The product was coated on release paper using a reverse roll coater to prepare a resin film having a resin basis weight of 80 g / m ² . A nylon 12 fiber nonwoven fabric (manufactured by Japan Vilene Co., Ltd., fiber basis weight 10 g / m ² ) is pasted on the surface of this resin film, and the nonwoven fabric is on both sides of the reinforcing fiber fabric while applying a tension of 10 N / m to the nonwoven fabric. A prepreg was prepared by continuously impregnating the resin composition at a processing speed of 4 m / min using a heat roll heated to 110 ° C. in a superimposed manner. There was a release paper on the surface of the prepreg after passing through the heat roll, and it was peeled off for inspection, but an embossed polyethylene film was attached immediately after the top release paper was peeled off to maintain tackiness. Reinforcing fiber fabric is a plain weave made of carbon fiber “Torayca (registered trademark)” T700GC-12K (12,000 fibers, tensile strength 4.9 GPa, tensile modulus 240 GPa, tensile elongation 2.1%) manufactured by Toray Industries, Inc. A woven fabric CF6273H and a fiber basis weight 193 g / m ² ) were used. The tack strength of the prepreg thus obtained was 13.7 N, the tack force when left in an environment of 24 ° C. and 50% RH for 20 days was 13.7 N, the drapeability was 24.5 N, and the determination of the unimpregnation rate Was Δ.

  Further, a honeycomb sandwich panel was obtained by the following method using this prepreg. Nomex honeycomb SAH1 / 8-8.0 (manufactured by Showa Aircraft Co., Ltd., model number: SAH1 / 8-8.0, thickness 12.7 mm) is used as the honeycomb core. The prepreg is the above-described woven prepreg and has a two-ply symmetrical laminated structure (± 45 °) / (0 ° / 90 °) on the top and bottom of the honeycomb core (the outermost layer is ± 45 ° with respect to the honeycomb core). did. Here, the dimensions of the honeycomb core and the prepreg are 40 cm (short direction) × 50 cm (longitudinal direction), and the prepreg is laminated so that the short direction is the ribbon (L) direction of the honeycomb core and the warp direction of the prepreg. did. Subsequently, the green body in which the prepreg was laminated on the honeycomb core was placed on an aluminum tool plate coated with a release agent, Fricoat 44-NC (manufactured by THE DEXTER CORPORATION). Further, after covering the green body with a nylon film, the inside of the nylon film (hereinafter abbreviated as “inside of the system”) was kept in a vacuum state, and then placed in an autoclave as it was. The pressure in the autoclave was increased to 0.15 MPa, then the pressure in the system was returned to normal pressure, and then the pressure in the autoclave was increased to 0.30 MPa, and then temperature increase was started. The pressure in the autoclave is kept at 0.30 MPa until the molding is completed, the temperature is raised to 180 ° C. at 1.5 ° C./min, and then left at 180 ° C. for 2 hours to cure the resin while the resin is cured. After bonding, the temperature was lowered to room temperature at 2 ° C./min to obtain a honeycomb cocure molded body, that is, a honeycomb sandwich panel. A sample was cut out from the obtained honeycomb sandwich panel to obtain a test piece, and the amount of porosity measured using this test piece was 0.04%. Moreover, when this test piece was used and the climbing drum peel strength between the skin panel on the aluminum tool plate side and the honeycomb core was measured according to ASTM D1781, the result was 41.4 N · m / m.

(Example 2)
A prepreg was prepared by continuously impregnating the resin composition at a processing speed of 6 m / min using a heat roll heated to 110 ° C. in the same manner as in Example 1. The tack of the prepreg thus obtained was 16.7 N, and after standing for 20 days, it was 15.7 N. Further, the drapeability was 22.6 N, the determination of the unimpregnation rate was Δ, the porosity of the molded product was 0.00%, and the climbing drum peel strength was 40.2 N · m / m.

(Example 3)
A prepreg was prepared by continuously impregnating the resin composition at a processing speed of 4 m / min while using a heat roll heated to 120 ° C. in the same manner as in Example 1. The tack of the prepreg thus obtained was 11.8 N, and after standing for 20 days, it was 10.8 N. Further, the drapeability was 38.6 N, the determination of the unimpregnated rate was ○, the amount of porosity of the molded product was 0.26%, and the climbing drum peel strength was 42.9 N · m / m.

Example 4
A prepreg was produced by continuously impregnating the resin composition at a processing speed of 6 m / min while using a heat roll heated to 120 ° C. in the same manner as in Example 1. The tack of the prepreg thus obtained was 13.7 N, and after standing for 20 days, it was 13.7 N. Further, the drapeability was 34.7 N, the determination of the non-impregnation rate was ○, the porosity of the molded product was 0.18%, and the climbing drum peel strength was 41.6 N · m / m.

(Example 5)
A prepreg was prepared by continuously impregnating the resin composition at a processing speed of 4 m / min using a heat roll heated to 130 ° C. in the same manner as in Example 1. The tack of the prepreg thus obtained was 9.8 N, and after standing for 20 days, it was 8.8 N. Further, the drapeability was 57.9 N, the determination of the unimpregnation rate was ○, the porosity of the molded product was 0.38%, and the climbing drum peel strength was 42.7 N · m / m.

(Example 6)
A prepreg was prepared by continuously impregnating the resin composition at a processing speed of 6 m / min using a heat roll heated to 130 ° C. in the same manner as in Example 1. The tack of the prepreg thus obtained was 9.8 N, and after standing for 20 days, it was 9.8 N. Further, the drapeability was 51.1 N, the determination of the non-impregnation rate was ○, the porosity of the molded product was 0.30%, and the climbing drum peel strength was 41.4 N · m / m.

(Example 7)
A prepreg was produced by impregnating the resin composition at a processing speed of 4 m / min while using a heat roll heated to 100 ° C. in the same manner as in Example 1. The cover glass was cracked and could not be measured when the prepreg thus obtained was peeled off. Further, the drapeability was 15.9 N, the determination of the non-impregnation rate was x, the amount of porosity of the molded product was 0.00%, and the climbing drum peel strength was 40.5 N · m / m.
(Example 8)
A prepreg was prepared in the same manner as in Example 1, and the top release paper was peeled off and left as it was. The tack force measured in the same manner as in Example 1 except that such a prepreg was used was 13.7 N, and was significantly reduced to 3.9 N when left for 20 days. The drapeability was 24.5 N, the determination of the unimpregnation rate was Δ, the porosity was 0.04%, and the climbing drum peel strength was 40.5 N · m / m.
(Comparative Example 1)
A resin film was prepared from the same matrix resin composition as in Example 1 using a reverse roll coater, and a prepreg was prepared without using a nonwoven fabric. The tack force measured in the same manner as in Example 1 except that such a prepreg was used was 13.7N, 13.7N when left for 20 days, drapeability was 18.1N, the unimpregnation rate was determined as Δ, and the porosity was 0. The climbing drum peel strength was 26.9 N · m / m.
(Comparative Example 2)
As in Example 1, when the prepreg was prepared with the unwinding tension of the nonwoven fabric of the component [C] being 0 N / m, the nonwoven fabric of the component [C] was attached before being attached to the resin film of the component [B]. A uniform prepreg was not obtained with wrinkles on the entire surface.
(Comparative Example 3)
As in Example 1, when a prepreg was prepared, before being attached to the resin film of the component [B], the nonwoven fabric of the component [C] was shrunk and the width was narrower than the woven reinforcing fiber of the component [A]. Thus, a uniform prepreg could not be obtained.

From the comparison between Examples 1 to 8 and Comparative Examples 1 to 3, the tack force related to the handleability at the time of molding, the drapeability, the amount of porosity indicating the quality of the molded body, and the climbing drum peel strength indicating the strength of the molded body, It can be seen that the prepreg of the present invention is greatly superior.
(Comparative Example 4)
Similarly to Example 1, a prepreg was produced by impregnating the resin composition at a processing speed of 4 m / min while using a heat roll heated to 140 ° C. The tack of the prepreg thus obtained was 5.9 N, 4.9 N when left for 20 days, and drapeability was 89.7 N. The tack force was greatly reduced and the laminate workability was difficult due to its rigidity. . Further, the determination of the unimpregnation rate was ○, the amount of porosity of the molded product was 0.53%, and the climbing drum peel strength was 41.5 N · m / m.

Claims (11)

A honeycomb prepreg for honeycomb self-adhesion comprising the following constituent elements [A], [B] and [C], wherein the constituent element [C] is disposed on the outer surface side of [A], and the surface tack force is A prepreg characterized by being 10 N or more.
[A]: Reinforcing fiber composed of continuous fibers [B]: Matrix resin [C]: Thermoplastic resin having voids and a continuous form   The prepreg according to claim 1, wherein the surface tack force after standing for 20 days under conditions of a temperature of 24 ° C. and a humidity of 50% is 10 N or more.   The thermoplastic resin of component [C] consists of one or more resins selected from the group consisting of polyamide, polyacetal, polyphenylene oxide, polyimide, polyetherimide, polyethersulfone, polyetheretherketone, and polyaramid. The prepreg according to 2.   The prepreg according to any one of claims 1 to 3, wherein the constituent element [A] is a carbon fiber.   The prepreg according to any one of claims 1 to 4, wherein the constituent element [A] is woven.   The prepreg according to any one of claims 1 to 5, wherein the constituent element [B] is made of a thermosetting resin.   The prepreg according to any one of claims 1 to 6, wherein a load value (draping property) when a tensile load is applied in a 45 ° direction with respect to the fiber direction and the deformation is 10% is 50 N or less.   The continuous production method of a prepreg according to any one of claims 1 to 7, wherein a pulling tension applied to the component [C] when pulling out from the scroll is 1 to 50 N / m.   The constituent element [C] is arranged in advance on the surface of the constituent element [B] formed into a film by applying to a support, and then the constituent element [A] is bonded and heated and pressurized. Item 9. A method for continuously producing the prepreg according to Item 8.   The continuous production method of a prepreg according to claim 8 or 9, wherein the heating temperature is 50 to 150 ° C and the applied pressure is in the range of 1 to 100 N / m in linear pressure. The prepreg manufacturing method according to any one of claims 8 to 10, wherein a cover film is attached to the surface of the prepreg immediately after the single-sided or double-sided support is peeled off.