JP5176564B2 - CFRP panel structure - Google Patents

Description

  The present invention relates to a CFRP panel structure formed by bonding an inner panel member and an outer panel member, and more particularly to a CFRP panel structure suitable as an automobile outer panel such as a hood hood, a door, or a roof for an automobile.

A panel structure in which an inner panel member and an outer panel member such as a hood hood of an automobile are joined and the outer panel member is required to have an undistorted appearance has been mainly made of a metal material such as steel or aluminum. On the other hand, since the demand for weight reduction has increased in recent years, carbon fiber reinforced plastic (hereinafter sometimes referred to as “CFRP”) that is lightweight and excellent in strength and rigidity is used as the most suitable material for weight reduction. Has come to be.

  The metal panel structure is joined by bending (hem processing) the outer peripheral part of the outer panel so as to sandwich the outer peripheral part of the inner panel, but the CFRP panel structure has the same structure. It cannot be adopted. This is because CFRP is a brittle material and the bent portion will be broken when it is bent. Therefore, when manufacturing a CFRP panel structure, a structure in which an inner panel member and an outer panel member are bonded to each other has been generally used.

  However, the outer panel member surface of the panel structure member using the adhesive structure is distorted, and there is a problem that it is difficult to obtain a beautiful surface.

  As shown in FIG. 1, when a hat-shaped inner panel member and an outer panel member having a flange portion and a standing wall portion at least partially are bonded, a portion 3a facing each other and an R portion of the inner panel member In the portion 3b where the adhesive protrudes, the thickness of the adhesive is greatly different. Generally, the adhesive shrinks by a few percent due to a chemical reaction during curing, but the outer panel member having a smaller curvature than the inner panel member having a hat shape has a lower rigidity and is pulled by the inner panel member. It will be. At this time, if the thicknesses of the adhesives are greatly different, a difference occurs in the absolute amount of shrinkage of the adhesives, and the outer panel member is deformed as shown in FIG.

  On the other hand, it is conceivable to suppress distortion of the appearance by scraping off the adhesive that protrudes from the R portion of the inner panel member, but it is difficult to scrape to the back of the R portion. Moreover, there are many cases in which a hand cannot enter the inside of the flange portion, which is not realistic.

Furthermore, for the purpose of reducing the scraping work of the adhesive, a method for preventing the adhesive from protruding as disclosed in Patent Document 1 has been proposed. However, in order to prevent the adhesive from sticking out stably, it is necessary to make the application amount of the adhesive smaller than the volume of the space constituted by the double-sided tape and the adherend. In this case, since the adhesive accumulates in the downward direction due to gravity, a portion that does not come into contact with the upper member to be bonded is generated, which causes a problem that the adhesive strength cannot be secured stably.
JP-A-62-135584

  Accordingly, the object of the present invention is to overcome the above-mentioned problems of the conventional panel structure, have a beautiful surface that is lightweight and highly rigid, has little distortion in appearance, and has a stable and strong adhesive strength. It is in providing a body, and in particular, in providing an automotive skin panel structure having such features.

To achieve the above object, the present invention adopts the following configuration. That is,
(1) A panel structure in which a hat-shaped inner panel member and an outer panel member having a flange portion and a standing wall portion at least in part are bonded to each other. A CFRP panel structure comprising a release layer in an outer edge portion of an opposing region and / or a portion adjacent to a flange portion of an inner panel member.

  (2) The CFRP panel structure as described in (1) above, wherein the release layer is a film bonded thereto.

  (3) When the thickness of the adhesive layer between the inner panel and the outer panel is t1, and the thickness of the release layer is t2, the relationship between t1 and t2 satisfies the following formula, (1) or The panel structure made of carbon fiber reinforced plastic according to (2).

  t2 / t1 ≦ 0.6 (formula).

  (4) The CFRP panel structure according to (2), wherein a contact angle of the film with water is 75 ° or more.

  (5) Peeling force between the film and the outer panel member or / and Peeling force between the film and the inner panel member is 4 N or less per 25 mm of film width, (2) to (4) ) A CFRP panel structure according to any one of the above.

  (6) The CFRP panel structure according to (1), wherein the release layer is a release agent.

  (7) The CFRP panel structure according to (1), wherein the release layer is a coating film, and the contact angle of the coating film with water is 75 ° or more.

  According to the present invention, since the adhesive protruding from the R portion of the inner panel member is not bonded to the outer panel member and / or the inner panel member, the outer panel member is moved toward the inner panel member even when the adhesive shrinks. The pulling force is significantly reduced. In addition, since the adhesive is applied more than the required amount and actively protrudes, there is little risk of insufficient strength due to insufficient adhesive. Accordingly, it is possible to obtain a panel structure that has a beautiful surface that is light and highly rigid, has little distortion in appearance, and has a stable and strong adhesive strength, which is difficult with a conventional panel structure.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The present invention is a panel structure in which a hat-shaped inner panel member and an outer panel member having a flange portion and a standing wall portion at least in part are bonded to each other, and the flange portion of the inner panel member of the outer panel member A CFRP panel structure having a release layer in an outer edge portion of a region opposite to and / or a portion adjacent to a flange portion of an inner panel member.

  The inner panel member of the present invention has a hat shape as shown in FIG. 1 and has a flange portion and a standing wall portion at least in part, and the CFRP panel structure according to the present invention includes the inner panel member. A part of the flange portion and the outer panel member are bonded to each other.

  Here, the CFRP panel structure according to the present invention has a release layer. The release layer includes an outer edge portion (3a in FIGS. 3 and 4: inside the dotted line portion) of the outer panel member facing the flange portion of the inner panel member, and a portion adjacent to the flange portion of the inner panel member (FIG. 3). 4-3c: outside of the dotted line part) or both. If a sufficient safety factor is set for the bonding area, the release layer should be placed at the flange area as shown in 4 in FIGS. However, it is more preferable in terms of suppressing distortion.

  The effect of the present invention, that is, even when the adhesive contracts, the force with which the outer panel member is pulled toward the inner panel member is reduced, and the adhesive is more actively applied than the required amount. As long as the effect of insufficient strength due to the lack of adhesive is less likely to occur, it has a release layer at either the outer edge portion or the portion adjacent to the flange portion of the inner panel member. There is no problem even if there is no part.

  The CFRP panel structure according to the present invention is not particularly limited in use, but is particularly suitable for an automobile outer panel. Specific examples include hood hoods, roofs, doors, trunk lids, and fenders.

  The panel structure in the present invention is made of CFRP. CFRP refers to a resin reinforced with carbon fibers (ie, carbon fiber reinforced plastic). CFRP is lighter than metal materials such as steel and aluminum and is superior in terms of strength and rigidity. Therefore, CFRP is suitable as a material for a panel structure that is lightweight and has high strength and rigidity, particularly an automobile outer panel.

  The type of carbon fiber used in the present invention is not limited at all. A PAN-based carbon fiber having an excellent property in terms of strength using acrylic fiber as a raw material, or a pitch-based carbon fiber having an excellent property in terms of elastic modulus such as petroleum pitch may be used. The form of the carbon fiber is not particularly limited. If high strength is required, continuous fibers are preferable. When it is desired to be inexpensive, SMC (sheet molding compound) obtained by cutting carbon fibers and pellet materials can be selected. When continuous fibers are used, a unidirectional material (UD material) in which carbon fibers are aligned in one direction or a woven material may be used, but the woven material is easier to form. Plain weaving, satin weaving, twill weaving, non-crimp cloth, etc. can be appropriately selected as the type of woven fabric. However, when clear weaving is used to show the weave on the product surface, the use of plain weaving increases design. In addition, satin weave and twill weave are good for drape, so they are preferably used when forming a three-dimensional shape with a deep depth.

  In addition to carbon fibers, other reinforcing fibers and auxiliary materials such as mats, non-woven fabrics, and fillers can be used for the purpose of improving surface design, moldability, and resin impregnation. For example, the use of a glass surface mat or the like may improve the smoothness of the surface and the resin impregnation property. Examples of the reinforcing fibers other than the carbon fibers include glass fibers, aramid fibers, PBO (polyparaphenylene benzobisoxazole) fibers, tyrano (titanium alumina) fibers, and nylon fibers. If the other reinforcing fiber has a content of less than 50% by mass of the entire reinforcing fiber, it is included in the CFRP referred to in the present invention.

  Furthermore, the laminated structure of CFRP is not particularly limited, and can be appropriately oriented according to the direction and magnitude of the force applied to the panel structure. In the case of an automobile outer panel, the orientation is generally based on a quasi-isotropic laminate in which fibers are evenly arranged in directions of 0 °, 90 °, + 45 °, and −45 °. This is because automobile outer panel has many large and shallow plate-like shapes, and working load is assumed to be both bending load and shear load such as torsion. However, it is preferable to provide anisotropy as appropriate according to the type of vehicle and the part to which it is applied.

  As the matrix resin constituting the CFRP of the present invention, an epoxy resin is preferable because of its good adhesion to fibers and high strength. In addition to epoxy resins, vinyl ester resins and unsaturated polyester resins can be selected. A thermoplastic resin such as nylon resin, ABS (acrylonitrile butadiene strain) resin, or PPS (polyphenylene sulfone) resin can also be selected. When used in a place exposed to a high temperature, a bismaleimide resin or a polyimide resin may be used. In addition, various additives can also be used. For example, when an ultraviolet absorber is mixed with a matrix resin, an effect of preventing the matrix resin from being deteriorated by ultraviolet rays can be obtained.

  As a method of molding the inner panel member and the outer panel member of the present invention, a generally known CFRP molding method can be applied. Among them, RTM molding (resin transfer molding) is suitable for molding automobile outer panel because it can produce large, lightweight, and highly rigid products in a short molding cycle. For applications that are mass-produced, press molding using SMC and injection molding using a material in which a thermoplastic resin is a matrix resin are suitable. Of course, autoclave molding, press molding and vacuum bag molding can be performed using general prepreg materials, and hand lay-up and VaRTM method (molding method in which the inside of the bag material is injected by vacuum suction) are applied. You can also

  Next, the type of adhesive used in the present invention is not limited at all. Specific examples include epoxy adhesives with excellent adhesive strength and abundant types, urethane adhesives that have excellent impact resistance and can be cured in a short time, and acrylic adhesives that are resistant to oil stains on the adherend. The strength of the adhesive generally depends on the thickness, and the thickness of the adhesive layer is preferably set thin from the viewpoint of lightness.

  The release layer used in the present invention can satisfy the function as long as it has releasability with respect to the adhesive used. In order to provide a flat or shallow three-dimensional curved surface, workability can be improved by attaching a film having releasability. Release tapes with a pre-applied adhesive on one side of the film are available on the market, so you can work more easily with this, and if it is a film with a release paper liner, use an automatic cutting machine in advance. It can also be used for mass production by cutting into two.

  In order to provide a release layer on a deep three-dimensional curved surface or a large area, it is better to apply a release agent or to apply a release paint and dry it to form a coating film. . When using a release agent or paint, it is necessary to mask the adhesive portion in advance before application so that the release agent or paint does not adhere. This is because when a release agent or a releasable paint adheres to the bonded portion, the adhesive strength is remarkably reduced. Moreover, it is necessary to dry the release agent and paint sufficiently using a hot air dryer, an infrared heater, or a method such as natural drying. This is because if the drying is insufficient, the adhesive may be dissolved in the adhesive applied later and the strength of the adhesive may be reduced.

  When using a film or paint, it is necessary to select one having sufficient releasability. As an index of releasability, it is convenient to use a contact angle with water. The required releasability for a general adhesive is that the contact angle with water is 75 ° or more. If the contact angle with water is 75 ° or less, the adhesive may adhere to the adhesive, and the appearance distortion may not be prevented. Examples of specific materials include PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) in the case of a film. ), ETFE (tetrafluoroethylene-ethylene copolymer) and the like, and polyolefins such as polyethylene and polypropylene. In the case of paints, silicone-based, fluorine-based and inorganic-based paints are listed. Moreover, when using a film, you may make it peel with the force of 4 N or less per film width 25mm by adjusting the adhesive between a film and an outer side panel member or an inner side panel member. This is because the film is peeled off due to the shrinkage of the adhesive and the outer panel member is not distorted. The release agent is originally intended to release the resin molded product and the mold, and is not particularly limited as long as it is a release agent for thermosetting resin molding. In particular, a fluorine-based mold release agent is preferable because it hardly dissolves in the adhesive.

In particular, when a film is used for the release layer, it is preferable that the relationship between t1 and t2 satisfies the following formula, where the thickness of the adhesive layer between the inner panel and the outer panel is t1, and the thickness of the release layer is t2. . In addition, when there is a distribution in the thickness of the adhesive layer between the inner panel and the outer panel and the release layer, ideally, it is desirable to satisfy the following formula on the entire surface of the adhesive layer and the release layer, It is desirable that the average thickness of at least the adhesive layer and the release layer satisfy the following formula. More preferably, the region of 50% or more of the total adhesive layer and the total release layer satisfies the following formula, more preferably 80% or more of the total adhesive layer and the total release layer. The region satisfies the following formula.
t2 / t1 ≦ 0.6 (formula).

  When the ratio of the film thickness in the adhesive layer thickness is high, the film itself has a sealing effect and inhibits the adhesive from being stretched to the required range, and the end face of the film layer becomes a wall and the adhesive is three-dimensionally. This is because the stress is concentrated by pulling around. This is because the film is composed of two layers of a base material layer portion and an adhesive layer portion, and the base material has a mold release effect, but the adhesive and the adhesive are bonded. As described above, it is preferable to reduce the thickness of the adhesive layer from the viewpoint of strength and light weight. However, by selecting the adhesive layer thickness / film layer thickness within the range satisfying the previous formula, the distortion can be further suppressed.

  Hereinafter, it demonstrates still in detail based on an Example. In addition, about each physical property, it measured as follows.

[Contact angle with water]
The contact angle was measured by the θ / 2 method. A small amount of water droplets were dropped on the horizontally held sample, and this was magnified by a CCD camera from the side. The radius r and height h of the water droplet were measured from this image, and the contact angle θ was determined by the following equation.
θ = 2 tan ⁻¹ (h / r).

[Stripping force per 25 mm film width]
The peeling force was measured according to the 180 ° peeling method defined in JIS Z 0237 (2000). The tape width was set to 25 mm, and this tape was attached to a CFRP plate to prepare a test piece. A universal testing machine was used for the test, the tip of the tape and the CFRP were chucked, and the force when the tape was peeled off at a speed of 300 mm / min in the direction in which the tape was folded back 180 ° was measured.

  In each of the examples and comparative examples, a CFRP automobile bonnet hood formed by adhesively bonding the outer panel member having the shape shown in FIG. 5 and the inner panel member having the shape shown in FIG. 6 is formed, and is reflected on the surface of the hood. The degree of distortion of the image of the fluorescent lamp was visually observed and compared. Moreover, a part of this bonnet hood was cut out to a width of 10 mm, and the state of destruction was compared by applying a peeling force to the bonded portion.

In Examples and Comparative Examples, as materials, two kinds of woven fabrics in which a PAN-based carbon fiber having a tensile strength of 4.9 GPa as a carbon fiber is plain woven to a basis weight of 200 g / m ² and 300 g / m ^2, and RTM as a matrix resin are used. A low-viscosity epoxy resin and an adhesive prepared for molding were heat-curable two-component mixed urethane adhesives.

  The outer panel member and the inner panel member were molded by the following method.

  First, the carbon fiber fabric is cut into the shape of the outer panel member, and 0 ° / 90 °, ± 45 °, ± 45 °, 0 ° / 90 ° with respect to the longitudinal direction of the vehicle body on the female die coated with the release agent. 4 sheets were laminated in this order. A polyester taffeta was placed thereon as a peel ply, and a polypropylene net was further placed thereon. Further, a cowl plate adapted to the approximate product shape was placed, a hose for extracting the air inside and a hose for injecting resin were set, and then the whole was covered with a nylon bag film.

  Next, after the inside air is evacuated to make a vacuum state, the epoxy resin is sucked from the resin injection hose, and the resin is sealed by bending the vacuum and resin injection hoses with the resin spread. It was left for 1 hour until it cured. At this time, the mold was heated by circulating hot water so that the temperature of the mold was 85 ° C. After the resin was cured, the bag film was peeled off, the cowl plate, the net, and the peel ply were peeled off, and then the molded product was removed from the mold to obtain an outer panel member. Next, the inner panel member panel member was also molded by the same method. The obtained outer panel had an average thickness of 1.3 mm and the inner panel was 1.1 mm.

Example 1
Adhesive tape coated with an adhesive was attached to one side of the PTFE film adjacent to the bonding position of the molded outer panel member. The contact angle of this pressure-sensitive adhesive tape with respect to water was 108 °, and the peeling force with the member was 9.1 N with a tape width of 25 mm. Adhesive was applied to the bonding position of the outer panel using a dedicated mixing and discharging device. At this time, the discharge amount of the adhesive was set to 250 g per minute, and the discharge gun was moved at a speed of 8 seconds per meter. This outer panel member was placed on a mold used for molding, further covered with an inner panel member, covered with a film, and then 350 kg of sand bags were placed thereon. After 5 minutes, the sand bag and the film were once removed, the adhesive protruding outside the inner panel member was scraped off, and then the film and sand bag were placed again and cured for 1 hour. At this time, the temperature of the mold was adjusted to 60 ° C.

  The appearance of the resulting hood hood for automobiles was a beautiful finish, and the image was not distorted even when a fluorescent lamp was projected on the surface. Furthermore, when the bonded portion was cut out with a diamond cutter to a width of 25 mm from the vicinity of the end portion of the hood hood for automobiles, and peeled off with a universal testing machine, the inner panel member, not the adhesive, was destroyed at a load of 530N.

(Examples 2-6, Comparative Examples 1-3)
In the same manner as in Example 1, the type of the release layer was changed as shown in Table 1 to produce Comparative Example 3 from Example 2 and observed and tested.

  In Example 2, an adhesive tape in which an adhesive was bonded to a PE (polyethylene) film was used. As in Example 1, the image of the fluorescent lamp reflected on the surface was not distorted. This is because the contact angle of the PE tape with water is 94 °, and sufficient curing for releasing from the adhesive can be secured.

  In Example 3, an adhesive tape in which a low adhesive strength adhesive was bonded to one side of a PET (polyester) film was used, but the fluorescent lamp image reflected on the surface was not distorted as in Example 1. It was. Although the contact angle with water of this film was 70 °, the adhesive strength was as low as 3.1 N with a width of 25 mm, so that the adhesive peeled off from the outer panel member due to the force due to the shrinkage of the adhesive, This is because the adhesive and the outer panel member were not bonded.

  In Example 4, a fluorine-based mold release agent was applied adjacent to the bonding position of the molded outer panel member. Before applying the release agent, it was cured with a masking tape so that the release agent did not adhere to the part to be bonded. After applying the release agent, the masking tape was peeled off. Furthermore, it was put on the metal mold | die heated at 85 degreeC for drying, and was left to stand for 1 hour. Thereafter, the inner panel member was bonded in the same procedure as in Example 1 and the appearance was observed. The image of the fluorescent lamp reflected on the surface was not distorted.

  In Example 5, a fluorine-based paint was applied adjacent to the bonding position of the molded outer panel member. Before applying the paint, it was cured with a masking tape so that the paint would not adhere to the part to be adhered, and after applying the paint with a brush, the masking tape was peeled off. Furthermore, after drying at room temperature for 3 hours, it was placed on a mold heated to 85 ° C. and left for 3 hours. Thereafter, the inner panel member was bonded in the same procedure as in Example 1 and the appearance was observed. The image of the fluorescent lamp reflected on the surface was not distorted.

  In Example 6, an adhesive tape in which an adhesive was bonded to the same PE (polyethylene) film as in Example 2 was used. However, the position where the adhesive tape was applied was not the outer panel member but was attached adjacent to the inner panel member adhesion position, but the fluorescent lamp image reflected on the surface was not distorted as in Example 1.

  In Comparative Example 1, a release layer such as a film was not provided. The fluorescent light reflected in the hood hood for automobiles was bent at the boundary of the adhesive.

  Comparative Example 2 uses a pressure-sensitive adhesive tape coated with a pressure-sensitive adhesive on one side of a PET film, and the portion of the fluorescent light reflected in the manufactured automobile hood hood appears to bend at the boundary of the adhesive portion; The part which does not bend was mixed.

  In Comparative Example 3, a urethane-based paint was used in the same procedure as in Example 5. However, the reflected fluorescent light had some parts that look bent.

(Comparative Example 4)
A double-sided tape having a thickness of 0.75 mm was affixed to both ends of the bonding position of the molded outer panel member as shown in FIG. At this time, the width of the bonding position was 25 mm, and a double-sided tape having a width of 5 mm was attached to both ends thereof, so that the substantial bonding width was 15 mm. Using an exclusive mixing and discharging device at the bonding position of the outer panel, the discharge amount of the adhesive was set to 125 g / min, and the adhesive was applied to the discharge gun at a speed of 6 seconds per meter. The amount of adhesive applied is 15 g per 1 m of adhesive length to completely fill the space created by a substantial adhesive width of 15 mm and a double-sided tape thickness of 0.75 mm. In order to prevent the adhesive from protruding even if there is a variation in the thickness of the adhesive, the amount of adhesive applied was 12.5 g per meter of adhesive length. This outer panel member was placed on a mold used for molding, further covered with an inner panel member, covered with a film, and then 350 kg of sand bags were placed thereon. After 5 minutes, the sand bag and the film were once unloaded, and the protruding adhesive was confirmed, but the adhesive did not protrude. Further, a film and a sand bag were placed again and cured for 1 hour. At this time, the temperature of the mold was adjusted to 60 ° C. Although the image was not distorted even when a fluorescent lamp was imprinted on the surface of the obtained hood hood for automobiles, the bonded portion was cut out in the same manner as in Example 1, and the peel test was performed with a universal testing machine. The adhesive part broke down. When the broken surface was observed, a portion where the CFRP adhered to the adhesive in black and a portion where the CFRP did not adhere and had a gloss were found approximately half each. The glossy part is not adhered to the CFRP and is solidified in contact with air. In the example, all of the bonding width of 25 mm was bonded, whereas in Comparative Example 4, only about half of the substantial bonding width of 15 mm was bonded, and therefore only 7.5 mm was effectively bonded.

(Example 7)
Adhesive tape coated with an adhesive was applied to one side of a PE (polyethylene) film adjacent to the adhesion position of the molded outer panel member. The tape thickness was about 0.3 mm. The outer panel and inner panel were sanded at the bonding position. Adhesive was applied to the bonding position of the outer panel using a dedicated mixing and discharging device. At this time, the discharge amount of the adhesive was set to 250 g per minute, and the discharge gun was moved at a speed of 8 seconds per meter.

  Adhesion was performed by assembling an adhesive mold having an upper and lower mold structure in a press apparatus, and setting the outer panel member and the inner panel member to the adhesive mold and pressing them. At this time, since the adhesive layer thickness could be arbitrarily set by the clearance between the upper and lower molds, the adhesive layers were bonded at two levels aiming at the adhesive layer thicknesses of 0.5 mm and 1.0 mm.

  After 5 minutes of adhesion, the adhesive that protruded to the outside of the inner panel member was scraped off, then returned to the adhesive mold and cured for 1 hour. At this time, the temperature of the mold was adjusted to 60 ° C. After demolding, after-curing was performed at about 100 ° C. to completely cure the adhesive.

  In the obtained hood with the adhesive layer thickness set to 0.5 mm, the fluorescent lamp reflected in the surface portion corresponding to the adhesion position between the outer panel and the inner panel was distorted. However, in the hood set to have an adhesive layer thickness of 1.0 mm, no distortion was observed in the fluorescent lamp reflected on the surface portion corresponding to the adhesion position between the outer panel and the inner panel.

  When the cross section around the strained part was observed, the hood with the adhesive layer set to 0.5 mm had a measured adhesive layer thickness of 0.3 to 0.5 mm, and the distance between the PE tape and the inner panel was extremely close over a wide range. / The place where it contacted was seen and the adhesive protrusion amount was partially insufficient. The cross-sectional position corresponding to the position where the fluorescent lamp was distorted was around the edge of the PE tape on the bonding position side. The hood with the adhesive layer set to 1.0 mm had an adhesive layer thickness of about 0.7 to 0.9 mm by actual measurement.

  The CFRP panel structure according to the present invention is particularly suitable when applied to an automobile outer panel such as a hood hood, a door, or a roof for automobiles, but the scope of application of the present invention is limited to these. It is not a thing.

An example of the cross section of the conventional panel structure made from CFRP. The schematic diagram which shows an example of the deformation | transformation of the cross section of the conventional panel structure made from CFRP. An example of the cross section of the panel structure made from CFRP which concerns on this invention (when a mold release layer is provided in the outer edge part of the area | region facing the flange part of the inner side panel member of an outer side panel member). An example of the cross section of the panel structure made from CFRP which concerns on this invention (when a mold release layer is provided in the part adjacent to the flange part of an inner side panel member). The perspective view of the outer side panel member which concerns on an Example. The perspective view of the inner side panel member which concerns on an Example.

Explanation of symbols

1: Outer panel member 2: Inner panel member 3: Adhesive 3a: A portion where the flange portion and the outer panel member of the inner panel member face each other 3b: A portion where the adhesive protrudes from the R portion of the inner panel member 3c: Outer panel Outer edge portion of region opposite to flange portion of inner panel member of member 3d: Portion adjacent to flange portion of inner panel member 4: Release layer

Claims (7)

A panel structure in which a hat-shaped inner panel member and an outer panel member each having a flange portion and a standing wall portion at least in part are bonded to each other, and is a region facing the flange portion of the inner panel member of the outer panel member A panel structure made of carbon fiber reinforced plastic having a release layer at a portion adjacent to the flange portion of the inner panel member and / or the inner panel member. The panel structure made of carbon fiber reinforced plastic according to claim 1, wherein the release layer is formed by adhering a film. The relationship between t1 and t2 satisfies the following expression, where t1 is the thickness of the adhesive layer between the inner panel and the outer panel, and t2 is the thickness of the release layer. Carbon fiber reinforced plastic panel structure.
t2 / t1 ≦ 0.6 (formula). The carbon fiber reinforced plastic panel structure according to claim 2, wherein a contact angle of the film with water is 75 ° or more. 5. The stripping force between the film and the outer panel member or / and the stripping force between the film and the inner panel member is 4 N or less per 25 mm of film width, according to claim 2. Carbon fiber reinforced plastic panel structure. 2. The carbon fiber reinforced plastic panel structure according to claim 1, wherein the release layer is a release agent. The carbon fiber-reinforced plastic panel structure according to claim 1, wherein the release layer is a coating film, and the contact angle of the coating film with water is 75 ° or more.

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