Patent Application
20200130320
The present application claims priority under 35 U. S. C. § 119 to Japanese Patent Applications No. 2018-202,329, filed on Oct. 26, 2018, and No. 2018-202,330, filed on Oct. 26, 2018, the contents of which are incorporated herein by reference in their entirety.
The present invention relates to a plastic laminated structure that includes a wave-shaped core member and a plate member coupled to the core member, and a method for producing the plastic laminated structure.
Plastic laminated structures that include a wave-shaped core member and a plate member coupled to the core member have been developed (see Japanese Patent Publication Nos. JP 2003-1,735 A, JP H06-170,993 A (1994), and JP H07-148,867 A (1995)).
Such a plastic laminated structure (corrugated plastic) that includes a wave-shaped core member and a plate member thermally bonded to a surface of the core member can be formed thick because air layers are provided in the plastic laminated structure. Accordingly, the plastic laminated structure can be lightweight and have high strength, in particular high flexural rigidity. The strength of the aforementioned plastic laminated structure can be further improved by using fiber-reinforced plastic which includes reinforcing fibers (e.g., carbon fibers or glass fibers) for the core member or plate member. Such a fiber-reinforced plastic laminated structure can provide so flexural rigidity to withstand high load in various types of applications.
Plastic laminated structures are subjected to surface treatment for most applications before use. To achieve this, a coating method has been developed for applying a coating onto surfaces of such a plastic laminated structure (see Japanese Patent Publication No. JP 2006-328,913 A).
The coating of plastic laminated structures that are subjected to surface treatment can provide various characteristics such as good appearance of their surface or thermal insulation improvement. However, it is difficult to firmly apply a coating onto a surface of a plastic plate without peeling off. In particular, it is more difficult to keep a coating on the surfaces without peeling off for a long time.
Therefore, the present invention has been developed to solve the above disadvantages. It is an object of the present invention to provide a plastic laminated structure that can firmly hold a surface treatment layer such as coating without peeling off.
A plastic laminated structure according to an aspect of the present invention includes a plate member of plate-shaped fiber-reinforced plastic and a core member of wave-shaped fiber-reinforced plastic. The plate member includes a thermoplastic resin and reinforcing fibers embedded in the thermoplastic resin. The core member is thermally bonded to the plate member, and includes a thermoplastic resin and reinforcing fibers that is embedded in the thermoplastic resin. A part of or the entire area of a main surface of the plate member includes smooth and rough surfaces. First asperities are formed on the rough surface on the main surface side. The smooth and rough surfaces are alternately arranged in stripes.
A plastic laminated structure according to the present invention can have the following features. However, the present invention is not limited to these.
In a plastic laminated structure according to an aspect, the smooth surface has second asperities. The difference between first asperities is greater than the second asperities.
A plastic laminated structure according to the present invention includes a plate member of plate-shaped fiber-reinforced plastic and a core member of wave-shaped fiber-reinforced plastic. The plate member includes a thermoplastic resin and reinforcing fibers embedded in the thermoplastic resin. The core member is thermally bonded to the plate member, and includes a thermoplastic resin and reinforcing fibers that is embedded in the thermoplastic resin. A part of or the entire area of a main surface of the plate member includes smooth and rough surfaces. The rough surface has larger roughness than the smooth surface. The smooth and rough surfaces are alternately arranged in stripes.
In a plastic laminated structure according to an aspect, the rough surface of the plate member is formed by the reinforcing fibers which are embedded in the thermoplastic resin. In this case, the rough surface can have very small asperities. The rough surface which has very small asperities in this plastic laminated structure can be formed by the reinforcing fibers by moving the thermoplastic resin with which space between the fibers is filled by melting the thermoplastic resin of the fiber-reinforced plastic. According to this plastic laminated structure, because the rough surface which has very small asperities can be formed by the reinforcing fibers, a surface treatment layer such as coating can be effectively fixed by its anchoring effect.
In a plastic laminated structure according to another aspect of the present invention, the rough surface can be formed by exposing the reinforcing fibers which are embedded in the thermoplastic resin from the main surface of the plate member. In this case, the anchoring effect can be increased. According to this plastic laminated structure, in order to form the rough surface which is formed by exposing the reinforcing fibers from the surface, the thermoplastic resin which includes the reinforcing fibers is melted. The melted, flowable resin can provide the rough surface which has very small asperities. In addition, the rough surface which is formed by exposing the reinforcing fibers from the surface can more firmly hold a surface treatment layer such as coating because it has good anchoring effect. In this case, the reinforcing fibers which are exposed from the surface form very small undercut-like recesses. Such a coating material can be held in these recesses. As a result, high anchoring effect can be provided.
In a plastic laminated structure according to another aspect of the present invention, it is preferable that the wave-shaped core member includes slant portions and bonded portions, and that the plate member includes bonded parts which have a surface as the smooth surface, and non-bonded parts which have a surface as the rough surface. The slant portions and bonded portions are arranged alternately so that parallel grooves are alternately arranged at a predetermined pitch on the both sides. The bonded parts of the core member are thermally bonded to the back surface of the bonded part. The core member is not thermally bonded to the non-bonded part.
According to this plastic laminated structure, the core member and the plate member are thermally and firmly bonded to each other, while very small asperity parts can be arranged in stripes. The reason is that, according to this plastic laminated structure, the smooth surfaces and the rough surfaces can be provided by the bonded parts which are thermally bonded to the core member and the non-bonded parts which are not thermally bonded to the core member, respectively, by thermally bonding the bonded parts of the wave-shaped core member, which has the parallel grooves which are formed by alternately arranging the slant portions and bonded portions and are alternately arranged at a predetermined pitch on its both sides, to the plate member. This plastic laminated structure can be produced by pressing the bonded portions of the core member and the plate member from the both sides and thermally bonding them to each other as shown in
In a plastic laminated structure according to another aspect of the present invention, the trapezoidal wave shape of the core member can be formed by alternately arranging slant-face portions and bonding portions so that parallel grooves are arranged at a predetermined pitch alternately on the both sides of the core member.
A bonded part that is formed by thermally bonding the bonding portions of the core member onto a back surface of the plate member can serve as the rough surface. A non-bonded part onto which the core member is not thermally bonded can serve as the smooth surface.
In a plastic laminated structure according to another aspect, the trapezoidal wave shape of the core member is formed by alternately arranging slant-face portions and bonding portions so that parallel grooves are arranged at a predetermined pitch alternately on the both sides of the core member.
The bonding portions have a width within the range not smaller than 20% and not greater than 100% of the thickness of the plastic laminated structure.
In a plastic laminated structure according to another aspect, the plastic laminated structure has a thickness not smaller than 0.8 mm.
In a plastic laminated structure according to another aspect of the present invention, a surface treatment layer can be formed on the main surface of the plate member. According to this plastic laminated structure, the plastic laminated structure can have suitable surface conditions for various applications by selecting a suitable surface treatment layer depending on the applications.
In a plastic laminated structure according to another aspect of the present invention, a coating can be used as the surface treatment layer. Also, the surface treatment layer can be a coating of laminated structure that includes a primer and a finishing coating material laminated on the primer.
In a plastic laminated structure according to another aspect of the present invention, the plate members can be thermally bonded to either side of the core member. In the case in which carbon fibers are embedded as the reinforcing fibers in the plate member and the core member, the plastic laminated structure can have very high strength. Also, the thermoplastic resin of the plate member and the core member can be selected from the group consisting of nylon, polycarbonate, acrylic resin, PET, PP, PPS, HTPE, phenoxy resin, and polyvinyl chloride.
According to the aforementioned plastic laminated structure, a suitable surface treatment layer for optimal surface treatment can be firmly fixed on the surface of the plastic laminated structure without peeling off. The reason is that, according to the aforementioned plastic laminated structure, because the smooth surfaces and the rough surfaces are alternately arranged in stripes on the surface, such a surface treatment layer can be firmly fixed by the anchoring effect of the rough surfaces. According to the aforementioned plastic laminated structure, because the rough surface is not formed on the entire surface of the plastic laminated structure but the smooth surfaces and the rough surfaces are arranged in stripes, the smooth surfaces can provide a flat surface which provides good appearance while a surface treatment layer can be firmly fixed on the surface of the plastic laminated structure by the anchoring effect of the rough surfaces which are arranged in stripes. In particular, according to the plastic laminated structure of the present invention, because the smooth surfaces and the rough surfaces are alternately arranged in stripes, the smooth surfaces can provide good appearance while a surface treatment layer can be entirely and firmly fixed on the surface of the plastic laminated structure by the anchoring effect of the rough surfaces which are arranged between the smooth surfaces.
A method for producing a plastic laminated structure according to another aspect is provided. The plastic laminated structure includes a plate member of plate-shaped fiber-reinforced plastic and core member of trapezoidal-wave-shaped fiber-reinforced plastic. The plate member includes a thermoplastic resin and reinforcing fibers embedded in the thermoplastic resin. The core member is thermally bonded to the plate member, and is formed of a thermoplastic resin and reinforcing fibers embedded in the thermoplastic resin. The core member includes slant portions and bonded portions that are arranged alternately whereby forming parallel grooves that are alternately arranged on the both sides. The method includes a placement step, an insertion step, and a bonding step. In the placement step, the core member is placed on the plate member. In the insertion step, press protrusions are inserted into their corresponding parallel grooves of the core member. In the bonding step, the bonded portions of the core member are bonded to the plate member by pressing the bonded portions of the core member by the press protrusions whereby bonding the bonded portions of the core member to the plate member.
In a method for producing a plastic laminated structure according to another aspect, the bonded portions of the core member can be bonded to the plate member by thermally melting the thermoplastic resin of the plate member and the core member in the bonding step.
In a method for producing a plastic laminated structure according to still another aspect, the bonded portions of the core member can be bonded to the plate member by an adhesive in the bonding step. A both thermosetting and thermoplastic material that is liquid or paste in its uncured state and becomes a thermoplastic material after cured can be used as the adhesive.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
In the following description, although terms for indicating particular directions or positions (e.g., “upper” and “lower”, and other terms including these terms) will be used as necessary for ease of understanding the present with reference to the drawings, the technical scope of the present invention is not limited by these terms. Portions attached with the same reference sign in different drawings show the portions or members same as or similar to each other.
It should be appreciated, however, that the embodiments described below are illustrations of a plastic laminated structure and a method for producing the plastic laminated structure to give a concrete form to technical ideas of the invention, and a plastic laminated structure and a method for producing the plastic laminated structure of the invention are not specifically limited to description below. Unless otherwise specified, any dimensions, materials, shapes and relative arrangements of the parts described below are given as an example and not as a limitation. In addition, the description for one embodiment may be applied to other embodiments or examples. Additionally, the sizes and the arrangement relationships of the members in the drawings are occasionally exaggerated for ease of explanation.
The plastic laminated structure according to the present invention includes a plate member and a core member. The plate and core members are formed of plate-shaped fiber-reinforced plastic which includes reinforcing fibers in thermoplastic resin. The core member has a trapezoidal wave shape. The plate member is thermally bonded to one side or the both sides of the core member. In the plastic laminated structure, a main surface of the plate member includes smooth and rough surfaces. First and second asperities are formed on the rough and smooth surfaces, respectively, on the main surface side. The difference between first asperities is greater than the second asperities. The difference between asperities can be defined by the standard deviation between asperities. It is noted that the smooth surface refers to a surface that has a standard deviation of asperities on its surface smaller than the rough surface from a microscopic viewpoint, and is not necessarily completely flat.
Smooth and rough surfaces are formed on the main surface of the plate member of the plastic laminated structure. The roughness of the rough surface is greater than the smooth surface. The smooth and rough surfaces are alternately arranged in stripes. Neither the smooth surface nor the rough surface extends the entire surface of the plate member. The rough surfaces are arranged in stripes on the main surface of the plate member. A coating which is applied to the main surface of the plate member can be fixed and prevented from peeling off by the anchoring effect of the stripe-shaped rough surfaces.
The following description will describe plastic laminated structures according to preferred embodiments of the present invention with reference to the drawings.
A plastic laminated structure 1 shown in
The plastic laminated structure 1 can be suitably used in applications which require light weight and high flexural rigidity. For example, the entire thickness (D) of the plastic laminated structure 1 can be not smaller than 0.8 mm, preferably not smaller than 1.5 mm, and more preferably not smaller than 2 mm depending on its application. The strength of the plastic laminated structure 1 can be high when it is thick. However, if too thick, the plastic laminated structure becomes too heavy. From this viewpoint, the entire thickness of the plastic laminated structure 1 can be not greater than 10 cm, preferably not greater than 3 cm, for example, and more preferably not greater than 1 cm in applications which requires light weight as important factor.
The thickness (d, t) of the plate member 2 and the core member 3 can be not smaller than 0.15 mm, preferably not smaller than 0.2 mm in terms of their strength, for example. The plate member 2 and the core member 3 become heavy if they are too thick. For this reason, the thickness of the plate member 2 and the core member 3 can be not greater than 1 mm, preferably not greater than 0.8 mm, more preferably not greater than 0.5 mm in terms of weight reduction, for example. The thickness of the plate member 2 can be same as the core member 3 in consideration of the strength and entire thickness (D) of the plastic laminated structure. Also, the plate member can be thicker than the core member. In this case, the surface strength can be high. Alternatively, the core member can be thicker than the plate member. In this case, the flexural rigidity can be high.
The plastic laminated structure according to the present invention can be suitably used for body sheet steel of vehicles, a case of electronic devices such as mobile phones and tablets instead of metal plates such as aluminum plate and magnesium plate. For example, the plastic laminated structure can be thin (lightweight) but have high flexural rigidity. For example, in the case in which the entire thickness (D) of the plastic laminated structure is 3 mm, and the thickness (d, t) of the plate member 2 and the core member 3 is 0.15 mm, this plastic laminated structure can have flexural rigidity seven times higher than and one-ninth of the weight of a high tensile steel with thickness of 0.65 mm. In various applications including vehicle body sheet steel application, weight and flexural rigidity are very important characteristics. The reason is that such applications require thin, lightweight and high flexural rigidity characteristics.
The trapezoidal-wave-shaped core member 3 of the plastic laminated structure 1 is thermally bonded to the back surface of the plate member 2. The trapezoidal wave shape of the core member 3 is formed by alternately arranging slant portions 3B and bonded portions 3A so that parallel grooves 3E are arranged at a predetermined pitch alternately on the both sides of the core member 3. The top of the trapezoidal wave serves as the bonded portion 3A. The bonded portion 3A is thermally bonded to the back surface of the plate member 2. The slant portion 3B of the illustrated core member 3 has flat inclined surfaces 3D. The both sides of the inclined surface 3D are exposed. This arrangement can provide good flexural rigidity.
The reinforcing fibers are embedded in plastic of the plate member 2 and the core member 3 of formed of fiber-reinforced plastic. A thermoplastic resin is included as the plastic of the plate member 2 and the core member 3 formed of fiber-reinforced plastic at least after they are thermally bonded to each other. For example, the thermoplastic resin of the fiber-reinforced plastic can be a thermoplastic resin such as nylon, polycarbonate, or polyvinyl chloride. Alternatively, a both thermosetting and thermoplastic material which has thermosetting physical properties in its uncured state and thermoplastic physical properties after cured by heating (e.g., phenoxy resin). The both thermosetting and thermoplastic material which has thermosetting physical properties in the uncured state is liquid or paste in the uncured state but can have thermoplastic physical properties after cured. However, the thermoplastic resin of the fiber-reinforced plastic according to the present invention is not limited to nylon, polycarbonate, and both thermosetting and thermoplastic material such as phenoxy resin. Other thermoplastic resins such as acrylic resin, PET, PP, PPS, and HTPE may be used instead of nylon, polycarbonate, or polyvinyl chloride.
Carbon fibers are preferably used as the reinforcing fibers. Fiber-reinforced plastics that include carbon fibers as reinforcing fibers have high strength. For this reason, such carbon fiber-reinforced plastics can be suitably used in particular for plastic laminated structures which are required to have high strength. However, fibers which can reinforce fiber-reinforced plastic such as glass fibers, aromatic polyamide group resin, PBO fibers, ultra high strength polyethylene fibers, and high strength polyarylate fibers may be embedded as the reinforcing fibers in the thermoplastic resin instead of carbon fibers.
The reinforcing fibers can be braided into a mesh shape as a fiber sheet. Also, the fiber-reinforced plastic can be constructed of a plurality of laminated layers as fiber sheets each of which includes the reinforcing fibers parallel to each other. The reinforcing fibers can be three-dimensionally integrally arranged at random orientations in a fiber sheet. The fiber-reinforced plastic can include the fiber sheet or sheets which are embedded in the thermoplastic resin. The fiber sheet consisting of reinforcing fibers which can be three-dimensionally integrally arranged at random orientations can be produced by wet papermaking methods, alternatively, can be produced by integrally arranging reinforcing fibers in a predetermined thickness in a dry manner as a nonwoven fabric. A sheet-shaped or plate-shaped fiber-reinforced plastic can be used for the plate member 2 and the core member 3. Alternatively, prepreg which includes a plastic and a fiber sheet impregnated with the plastic can be used for the plate member 2 and the core member 3. In the case of prepreg of thermoplastic resin, the plastic laminated structure 1 is produced by curing the plastic in a process for thermally bonding the core member 3 to the plate member 2.
In a wet paper making method, paper making slurry which includes suspension of reinforcing fibers in water is prepared. The suspension of reinforcing fibers is transformed into a reinforcing fiber sheet in a wet paper making manner. In this method, a fiber sheet can be transformed from paper making slurry which includes suspension of two or more types of reinforcing fibers and additive (e.g., inorganic powder). Also, a fiber sheet can be transformed from paper making slurry which includes suspension of powdered or very small granular thermoplastic resin or a both thermosetting and thermoplastic material in the uncured state in addition to the reinforcing fibers in water. After that, the fiber-reinforced plastic can be produced by pressing this fiber sheet in a dried and heated state. This method can provide a fiber-reinforced plastic which includes a fiber sheet including uniformly distributed fibers, and has good flexural rigidity. In the case in which various types of additives are added and uniformly distributed, fiber-reinforced plastic can be mass-produced by this method. In addition, this method can produce fiber-reinforced plastic by uniformly distributing various types of reinforcing fibers which have different material, length, thickness, and the like. For this reason, inexpensive recycled materials can be used for the reinforcing fibers. Simultaneously, fiber-reinforced plastic having good physical properties can be mass-produced. However, the present invention is not limited to a particular method for producing fiber-reinforced plastic.
The bonded portions 3A of the plastic laminated structure 1 shown in
In the illustrated plastic laminated structure 1, the inclination angle (α) between the slant portion 3B and the plate member 2 is approximately 70°, the width (W) of the bonded portion 3A is approximately 50% of the entire thickness (D) of the plastic laminated structure. However, the inclination angle (α) of the slant portion 3B of the core member 3 can be dimensioned not smaller than 30° and smaller than 90°, preferably not smaller than 45° and not greater than 80°. Also, the width (W) of the bonded portion 3A can be dimensioned not smaller than 20% and not greater than 100%, preferably not smaller than 30% and not greater than 70%, and more preferably not smaller than 35% and not greater than 60% of the thickness (D) of the plastic-laminated-structure 1.
Smooth and rough surfaces 2a and 2b are arranged on the main surface of the plate member 2 of the plastic laminated structure 1. The rough surface 2b has larger roughness than the smooth surface 2a. The smooth surfaces 2a and the rough surfaces 2b are alternately arranged in stripes. A surface treatment layer 30 such as coating 31 can be firmly fixed on the main surface of the plate member 2 by the rough surface 2b when adhering to the main surface of the plate member 2. In the plastic laminated structure 1, the smooth surface 2a and the rough surface 2b are preferably arranged in stripes on the whole surface of the plate member. This arrangement can prevent the surface treatment layer from peeling off as a whole. However, the rough surfaces 2b are necessarily arranged on the entire surface of the plate member of the plastic laminated structure 1 in stripes. The smooth surfaces 2a and the rough surface 2b may be arranged in stripes on a limited area of the plate member where the surface treatment layer is likely to peel off.
The rough surfaces 2b are preferably formed by the reinforcing fibers which are embedded in the thermoplastic resin of the fiber-reinforced plastic as a component of the plate member 2 of the plastic laminated structure 1. In this plastic laminated structure 1, the rough surfaces 2b are formed by partially protruding the reinforcing fibers, which are embedded in the thermoplastic resin of the plate member 2, from the main surface of the plate member. Specifically, in this plastic laminated structure 1, the embedded reinforcing fibers are exposed from the surface by heating the plate member 2 and melting the thermoplastic resin of the fiber-reinforced plastic of the plate member 2. The melted thermoplastic resin moves from the reinforcing fibers on the main surface side so that the reinforcing fibers can be partially exposed. The rough surface 2b has very small asperities which are formed by the thin reinforcing fibers. In addition, the reinforcing fibers form very small undercut-like recesses on the rough surface 2b. As a result, the surface treatment layer 30 can be more firmly fixed by the anchoring effect of the rough surface.
In the case in which the reinforcing fibers of the plate member 2 are three-dimensionally arranged at random orientations, random asperities can be formed by exposing the reinforcing fibers, which are three-dimensionally arranged at random orientations, from the main surface of the plate member by melting the thermoplastic resin. In particular, in this fiber-reinforced plastic, because the reinforcing fibers are three-dimensionally integrally arranged at random orientations, the intersection between the fibers will protrude higher. As a result, this rough surface 2b can provide a higher anchoring effect. In the case in which the reinforcing fibers of the fiber-reinforced plastic of the plate member 2 are arranged parallel to each other, the thermoplastic resin between the reinforcing fibers will move toward the back surface side so that space is created between reinforcing fibers when the thermoplastic resin is melted. As a result, the rough surface 2b is formed.
The core member 3 and the plate member 2 of the plastic laminated structure 1 can be thermally bonded to each other by pressing the bonded portions 3A of the core member 3 and the plate member 2 which are placed on one another when the thermoplastic resin is brought in its melted state by heating the plate member 2 and the core member 3. The main surface of the plate member of the plastic laminated structure 1 includes bonded parts 2x and non-bonded parts 2y. The bonded part 2x serves as the smooth surface 2a, and is thermally bonded to the bonded portion 3A of the core member 3. The non-bonded part 2y serves as the rough surface 2b, and is not thermally bonded to the bonded portion 3A of the core member 3. The reason is that the core member 3 and the plate member 2 in the bonded part 2x are pressed from the both sides, but the core member 3 in the non-bonded part 2y is not pressed by the plate member 2 in the process for thermally bonding the core member 3 to the plate member 2. In the bonded part 2x, the plate member 2 and the core member 3 are pressed from the both sides after placed on one another. As a result, the main surface of the plate member 2 can be the smooth surface 2a. On the other hand, in the non-bonded part 2y, the main surface of the plate member contacts the pressure face but the core member 3 is not pressed. Accordingly, the melted thermoplastic resin will move from areas between the reinforcing fibers. As a result, the rough surface 2b can be formed by the reinforcing fibers. In particular, the reinforcing fibers can provide the rough surface 2b with very small asperities. In this plastic laminated structure 1, the smooth and rough surfaces 2a and 2b are formed on the bonded and non-bonded parts 2x and 2y of the plate member 2, respectively, by thermally bonding the bonded portions 3A of the trapezoidal wave-shaped core member 3 to the plate member 2. As a result, the stripe-shaped smooth and rough surfaces 2a and 2b are alternately formed on the surface of the plate member.
In the plastic laminated structure 1, after the plate member 2 and the core member 3 are heated to a temperature in which their thermoplastic resin becomes its melted state, the plate member 2 and the core member 3 which include melted thermoplastic resin are placed on one another, and contact areas between the plate member 2 and the bonded portions 3A of the core member 3. As a result, the core member 3 and the plate member 2 can be thermally bonded to each other. In this method, in the process for thermally bonding the plate member 2 to the core member 3, after the plate member 2 and the core member 3 in which their thermoplastic resin is heated to its melted state are placed on one another, the bonded portions 3A of the core member 3 are pressed against the plate member 2 so that the core member 3 is thermally bonded to the plate member 2.
The fiber-reinforced plastic of the core member 3 is formed into a trapezoidal wave shape by a forming press 10 shown in
The opposed forming surfaces 11X of the forming dies 11 have trapezoidal wave shapes which can mesh each other whereby sandwiching the fiber-reinforced plastic material plate 9. The fiber-reinforced plastic material plate 9 of the core member 3 in its heated state is sandwiched between the forming surfaces 11X, and formed into the trapezoidal wave shape. As shown in
In order to heat and press the fiber-reinforced plastic material plate 9 and to cool it, circulation paths for heating and for cooling (not shown) are formed in the forming dies 11. A fluid (e.g., heating oil) circulates through the heating circulation path, and heats the forming surface 11X. Also, a fluid (e.g., cooling water) circulates through the cooling circulation path, and cools the forming surface 11X. The heating circulation path is connected to a heating system which circulatively provides a liquid (e.g., hot water or heating oil) or gas (e.g., steam). The cooling circulation path is connected to a cooling system which circulatively provides a liquid such as cooling water or a refrigerant which can provide a cooling effect by heat of vaporization when evaporated. The heating system heats the fluid so that the heated fluid circulates through the circulation path of the forming die 11. The cooling system cools the fluid so that the cooled fluid circulates through another circulation path of the forming die 11.
The aforementioned forming press 10 forms the fiber-reinforced plastic material plate 9 into the trapezoidal wave shape as follows.
1. The cylinder 12 raises the upper forming die 11B while keeping its forming surface 11X in the horizontal orientation so that the forming dies 11 are opened. The fiber-reinforced plastic material sheet 9 is then placed on the forming surface 11X that is the upper surface of the lower forming die 11A.
2. A heating fluid (e.g., heating oil or steam) circulates through the circulation paths of both the forming dies 11 so that the forming surfaces 11X of the forming die 11 are brought in its heated state.
3. The cylinder 12 lowers the upper forming die 11B so that the fiber-reinforced plastic material sheet 9 in its heated state is pressed by the forming surfaces 11X of the forming dies 11, and formed into the trapezoidal wave shape.
4. Circulation of the heating fluid through the circulation paths of both the forming dies 11 is stopped, and cooling fluid circulates through other circulation paths so that the forming surfaces 11X are cooled.
5. After the fiber-reinforced plastic 9 which is formed in the trapezoidal wave shape is cooled, the cylinder 12 raises the upper forming die 11B. The trapezoidal-wave-shaped fiber-reinforced plastic material sheet 9 is removed as the core member 3 from the forming dies 11.
In the case in which thermoplastic resin is used for the core member 3 of the fiber-reinforced plastic, the core member 3 is cooled a temperature in which its thermoplastic resin is cured, and is then removed from the forming dies 11. In the case in which a both thermosetting and thermoplastic material is used for the core member 3, the core member 3 can be removed from the forming dies 11 when the material in its thermosetting resin state is cured and becoming thermoplastic resin.
It should be noted that an apparatus of producing the core member and a method of producing the core member are not limited to the above mentioned apparatus or method, rather other apparatus or method which is capable of forming the trapezoidal-wave-shaped core member are also available. For example, other apparatus of producing the core member forms the core member to trapezoidal-wave-shape as a whole by forming single trapezoidal-wave-shape on the fiber reinforced plastic step by step.
In this plastic laminated structure 1, after the bonded portions 3A of the core member 3 contact the plate member 2, the contact areas are pressed from the both sides and heated. Accordingly, the thermoplastic resin of the bonded portions 3A of the core member 3 and the plate member 2 is melted, simultaneously the bonded portions 3A of the core member 3 and the plate member 2 is are pressed. As a result, the core member 3 is thermally bonded to the plate member 2. According to this method, the plate member 2 is thermally bonded to the core member 3 by placing the trapezoidal-wave-shaped core member 3 on the plate member 2 and sandwiching the contact areas between the core member 3 and the plate member 2 by the pair of heated hot plates, and then heating and pressing the contact areas by the hot plates.
The plate member 2 of the plastic laminated structure 1 shown in
After bonding the plate member 2 and the core member 3 by heating and pressing them, the lower hot plate 26A and the upper hot plate 26B cool the plate member 2 and the core member 3. Subsequently, the lower hot plate 26A and the upper hot plate 26B remove the pressure. As a result, the plastic laminated structure 1 can be taken out from the hot plates 26. The upper and lower hot plates 26 are heated by heating a refrigerant (e.g., heating oil) which circulates through them, and are then cooled by cooling a fluid which circulates through them. In order to cool the plate member 2 and the core member 3 after thermally bonding the plate member 2 and the core member 3 by heating and pressing them, heating and cooling circulation paths (not shown) are formed in the hot plates 26 similar to the forming dies 11. The heating fluid (e.g., heating oil) which circulates through the heating circulation path heats the surface of the lower hot plate 26A and the press protrusions 28 of the upper hot plate 26B. The cooling fluid (e.g., cooling water) which circulates through the cooling circulation path cools the surface of the lower hot plate 26A and the press protrusions 28 of the upper hot plate 26B. The heating circulation path is connected to a heating system which circulatively provides liquid (e.g., hot water or heating oil) or gas (e.g., pressurized steam). The cooling circulation path is connected to a cooling system which circulatively provides liquid such as cooling water and a refrigerant which can provide a cooling effect by heat of vaporization when evaporated. The heating system heats the fluid so that the heated fluid circulates through the circulation path of the hot plate 26. The cooling system cools the fluid so that the cooled fluid circulates through another circulation path of the hot plate 26.
The aforementioned bonding apparatus 25 bonds the plate member 2 to the core member 3 as follows.
1. The cylinder 22 raises the upper hot plate 26B while keeping the upper and lower hot plates 26 in the horizontal orientation so that the hot plates 26 are opened. Subsequently, the plate member 2 is placed on the lower hot plate 26A, and the core member 3 is then placed on the plate member 2. The core member 3 is positioned so that the press protrusions 28 of the upper hot plate 26B are guided into their corresponding parallel groove 3E.
2. Heating fluid (e.g., heating oil or steam) circulates through the circulation paths of both the hot plates 26 so that the surface of the lower hot plate 26A and the press protrusions 28 of the upper hot plate 26B are brought in their heated state.
3. The cylinder 27 lowers the upper hot plate 26B so that the core member 3 and the plate member 2 are heated and pressed by the upper and lower hot plates 26. Accordingly, the plastic laminated structure 1 is produced by thermally bonding the bonded portions 3A of the core member 3 to the plate member 2.
4. Circulation of the heating fluid through the circulation paths of both the hot plates 26 is stopped, and cooling fluid circulates through the circulation paths so that the surface of the lower hot plate 26A and the press protrusions 28 of the upper hot plate 26B are cooled.
5. After the heated areas of the plastic laminated structure 1, which is constructed of the core member 3 and the plate member 2 thermally bonded to each other, are cooled, the cylinder 27 raises the upper hot plate 26B so that the plastic laminated structure 1 is taken out from the hot plates 26.
The removal of the plastic laminated structure 1 from the hot plates 26 is performed after the thermoplastic resin of the fiber-reinforced plastic is cured. In the case in which the core member 3 and the plate member 2 are thermally bonded to each other by the fiber-reinforced plastic of a both thermosetting and thermoplastic material or a both thermosetting and thermoplastic material, the plastic laminated structure 1 can be removed from the hot plates after the both thermosetting and thermoplastic material in its thermoplastic resin state turns into its thermoplastic resin state, and the core member 3 and the plate member 2 are cooled.
In the case of the fiber-reinforced plastic of thermoplastic resin, after the thermoplastic resin is heated and melted, the plate member 2 and the core member 3 are pressed from the both sides and thermally bonded to each other. The plate member 2 and the core member 3 of fiber-reinforced plastic can be thermally bonded to each other without adhesives. However, the plastic laminated structure 1 can be produced by thermally bonding them through an adhesive. For example, the plate member 2 and the core member 3 may be thermally bonded through an adhesive which can be melted by heat.
In the case in which the plastic laminated structure 1 is produced by thermally bonding the plate member 2 and the core member 3 by an adhesive to each other, thermoplastic resins which can be melted by heat such as hot-melt adhesive can be used as the adhesive. Such a hot-melt adhesive, for example, a hot-melt adhesive which has a sheet shape in its non-melted state can be prepared, and be placed on the back surface of the plate member 2 when used. In the case in which such a sheet-shaped hot-melt adhesive is placed on the back surface of the plate member 2, the thermoplastic resin of the hot-melt adhesive can be melted by heating the plate member 2. As a result, the plate member 2 and the core member 3 can be bonded to each other by pressing them from the both sides. At this time, the thermoplastic resin of the plate member 2 can be also melted when heated together with the hot-melt adhesive. Accordingly, the smooth surface 2a is formed in the bonded part 2x in which the melted thermoplastic resin is thermally bonded to the plate member 2 and the core member 3 by pressing them from the both sides. The rough surface 2b is formed in the non-bonded part 2y in which the plate member 2 and the core member 3 are not pressed from the both sides.
Prepreg of both thermosetting and thermoplastic material can also be used for the fiber-reinforced plastic. Such prepreg of both thermosetting and thermoplastic material includes a fiber sheet impregnated with the both thermosetting and thermoplastic material in its uncured state. The both thermosetting and thermoplastic material has both thermosetting resin physical properties and thermoplastic resin physical properties. The both thermosetting and thermoplastic material can be a phenoxy resin which is liquid or paste in its uncured state and exhibits thermosetting resin physical properties but can have thermoplastic physical properties after cured. “NS-TEPreg (registered trademark)” manufactured by NIPPON STEEL & SUMIKIN MATERIALS CO., LTD. can be used as such prepreg of both thermosetting and thermoplastic material.
Prepreg of both thermosetting and thermoplastic material is used for the plate member 2 or the core member 3. The plate member 2 and the core member 3 are bonded to each other by curing the both thermosetting and thermoplastic material. In the case in which prepreg of both thermosetting and thermoplastic material is used, after the plate member 2 and the core member 3 are placed on one another, the both thermosetting and thermoplastic material is cured by heat. The cured both thermosetting and thermoplastic material becomes thermoplastic resin. When the plate member 2 and the bonded portions 3A of the core member 3 are pressed from the both sides, the plate member 2 and the core member 3 are thermally bonded to each other by the both thermosetting and thermoplastic material as thermoplastic resin. Prepreg of both thermosetting and thermoplastic material can be used for one of or both the plate member 2 and the core member 3. In the case in which prepreg of both thermosetting and thermoplastic material is used for the plate member 2 of the plastic laminated structure 1, because the prepreg of both thermosetting and thermoplastic material is cured when heated and pressed in the thermally bonding process, the main surface of the plate member in the bonded part 2x can be the smooth surface 2a which provides good appearance, while the rough surface 2b is formed on the main surface of the plate member in the non-bonded part 2y in which pressure is not applied. In the case in which prepreg of both thermosetting and thermoplastic material is used for the core member 3, after formed in the trapezoidal wave shape, the prepreg of both thermosetting and thermoplastic material is placed on and thermally bonded to the plate member 2. In the case in which prepreg of both thermosetting and thermoplastic material is used for both the plate member 2 and the core member 3, bonding strength between the plate member 2 and the core member 3 of the plastic laminated structure 1 can be high.
The shape of the aforementioned prepreg of both thermosetting and thermoplastic material can be kept even in the uncured state of a both thermosetting and thermoplastic material by controlling the uncured state. In the case in which prepreg of both thermosetting and thermoplastic material is used for the core member, the prepreg is formed into the trapezoidal wave shape with the shape of the prepreg being kept in a sheet shape by controlling its uncured state. After that, the trapezoidal-wave-shaped core member is placed on and thermally bonded to the plate member 2. More specifically, the prepreg is sandwiched between a pair of hot-forming rollers, and is formed into the trapezoidal wave shape. The hot-forming rollers for forming the prepreg completely cure the both thermosetting and thermoplastic material by heating and pressing it. Alternatively, the hot-forming rollers for forming the prepreg do not completely cure the both thermosetting and thermoplastic material but cure it to a state in which the trapezoidal wave shape of the prepreg can be kept when placed on the plate member 2.
The plastic laminated structure 1 is often formed into three dimensional shapes in many applications. In the case in which a thermoplastic resin is used as plastic which includes reinforcing fibers of the fiber-reinforced plastic of the plate member 2 and the core member 3 of the plastic laminated structure 1, and the plate member 2 and the core member 3 are bonded by a thermoplastic resin to each other, after the plastic laminated structure 1 is mass-produced in a plate shape, the mass-produced plastic laminated structure 1 can be formed into a desired three dimensional shape by heating and pressing depending on its application. In order to shape the plate-shaped plastic laminated structure 1 into a certain three dimensional shape, the plate member 2 and the core member 3 are thermally bonded by a thermoplastic resin to each other.
In a process for thermally bonding the bonded portions 3A of the core member 3 to the plate member 2 by pressing them against one another shown in
The surface treatment layer 30 is applied onto the main surface of the plate member 2 of the plastic laminated structure 1 shown in
The coating 31 in the aforementioned plastic laminated structure 1 can be fixed as the surface treatment layer 30 by coating the main surface of the plate member with coating materials as follows.
A primer 32 is applied onto the main surface of the plate member of the plastic laminated structure 1 in a primer-coating process. The coating can be firmly fixed on the main surface of the plate member by the primer 32 so that the main surface of the plate member 2 can be smooth. In addition, the primer 32 applies a base color to the main surface of the plate member 2. The primer-coating process includes first and second primer-coating processes. In the first primer-coating process, a sealer 32A is applied onto the main surface of the plate member 2, and the sealer 32A is fixed onto the rough surfaces 2b of the plate member 2 by the anchoring effect. In the second primer-coating process, base color paint 32B is applied onto the surface of the sealer 32A so that the base color is applied to the plate member 2. As a result, the primer coat 32 is formed.
The first primer-coating process can prevent the primer 32 from peeling off the plate member 2 after the primer 32 is fixed on the plate member 2. The sealer 32A which is used in this process enters the rough surface 2b on the main surface of the plate member so that the primer 32 can be firmly fixed on the plate member 2. More specifically, the sealer 32A is a low-viscosity liquid coating such as polyester or urethane group material, and seals the porous surface of the rough surface 2b of the plate member 2. As a result, the sealer 32A can be firmly fixed on the plate member 2 by the anchoring effect.
The base color paint 32B applies a light color close to white to the main surface of the plate member 2 in the second primer-coating process. The base color paint 32B can almost completely eliminate color unevenness of the primer so that the entire surface of the plate member 2 can be uniformly colored.
In the primer-coating process, an ultraviolet curing coating (UV coating) can be applied onto the surface of the sealer 32A in a process following to the first primer-coating process, or UV coating can be applied onto the surface of the base color paint 32B in a process following to the second primer-coating process. Such a UV coating is quickly cured by ultraviolet radiation. After the UV coating is cured by the ultraviolet radiation, the entire surface of the UV coating can be uniformly ground to a smooth surface by a brush sander or the like. In the case in which such a UV coating is applied onto the sealer 32A or the base color paint 32B, the primer 32 can be tough.
In a finishing process, a transparent or translucent finishing coating material 33 is applied onto the surface of the base color paint 32B. For example, the finishing coating material 33 can be applied by a roll coater in the finishing process. In a process following to the finishing process, also, a UV coating can be applied onto the surface of the finishing coating material 33 which has been applied in the finishing process. In the case in which such a UV coating is applied onto the finishing coating material 33, the surface of the finishing coating material 33 can be tough.
Although the plate member 2 has been described to be bonded to one side of the core member 3 in the aforementioned plastic laminated structure 1, the plate members 2 can be bonded to the both sides of the core member 3. In the case in which the plate members 2 are bonded to the both sides of the plastic laminated structure 1, one of the plate members 2 is first thermally bonded to one surface of the core member 3 by pressing the bonded portions 3A of the core member 3, while another plate member 2 is bonded by an adhesive which is applied on areas between the plate member 2 and the bonded portions 3A of the core member 3, or is bonded by pressing the contact areas between the plate member 2 and the core member 3 in the melted state when the contact areas is heated by using a heater.
The plate member 2 of the plastic laminated structure 1 shown in
The bonding apparatus 20 shown in
The plate member 2 of the plastic laminated structure 1 shown in
In the bonding apparatus 20 shown in
Also, the plastic laminated structure 1 can have a structure shown in
In particular, because the contact areas between the bonded portions 3A of the core member 3 and the plate member 2 are strongly pressed by the press protrusions, the thermoplastic resin of the core member 3 and the plate member 2 can be surely heated to its melting temperature. As a result, the thermoplastic resin of the core member 3 and the plate member 2 can be surely melted so that the core member 3 and the plate member 2 can be integrally bonded to each other. At this time, because the thermoplastic resin in the areas which are strongly pressed by the press protrusions can be surely heated to its melting temperature, such very small asperities can be formed on the surface of the thermoplastic resin when the melted the thermoplastic resin is cured. Accordingly, in this plastic laminated structure 1, in the bonded parts 2x in which the bonded positions 3A of the core member 3 are thermally bonded to the plate member 2, the thermoplastic resin is surely melted so that the rough surface 2b is formed, while in the non-bonded parts 2y in which the bonded positions 3A of the core member 3 are not thermally bonded to the plate member 2, the thermoplastic resin melting is limited so that the rough surface 2b is not formed but the smooth surface 2a is formed. In this plastic laminated structure 1, the rough and smooth surfaces 2b and 2a are formed on the bonded and non-bonded parts 2x and 2y of the plate member 2, respectively, by thermally bonding the bonded portions 3A of the trapezoidal wave-shaped core member 3 to the plate member 2. As a result, the stripe-shaped rough and smooth surfaces 2b and 2a can be alternately formed on the surface of the plate member. The surface treatment layer 30 can be more firmly fixed on the surface of the plate member 2 by the anchoring effect of the rough surfaces 2b which are formed on the surface of the plate member 2.
The plastic laminated structure 1 shown in
In this illustrated plastic laminated structure 1, the plate member 2 is bonded to one side of the core member 3.
The plate and core members 2 and 3 are formed of carbon-fiber-reinforced plastic which includes nylon 6 and carbon fibers embedded in the nylon 6.
The mixing ratio of nylon 6 to carbon fibers in the carbon fiber reinforced plastic is 75:25 in volume ratio. The entire specific gravity of the carbon fiber reinforced plastic is 1.32.
The carbon fibers are three-dimensionally integrally arranged at random orientations and embedded in the nylon 6 in the carbon fiber reinforced plastic.
The thickness (d, t) of the plate member 2 and the core member 3 is 0.3 mm.
The core member 3 has a trapezoidal wave shape which is obtained by connecting the bonded portions 3A to the slant portions 3B of the inclined surface 3D. The width (W) of the bonded portion 3A is 1.6 mm. The inclination angle (α) between the slant portion 3B and the plate member 2 is 70°. The entire thickness (D) of the plastic laminated structure 1 is 3 mm. It can be said that the trapezoidal wave shape is formed of high wave.
The plate member 2 and the core member 3 are thermally bonded by the pair of hot plates 26 to each other as shown in
The bonded parts 2x to which the bonded portions 3A of the core member 3 are thermally bonded, and the non-bonded parts 2y to which the core member 3 is thermally not bonded are alternately arranged in stripes on the plate member 2. After the core member 3 is thermally bonded to the back surface, the bonded parts 2x of the plate member 2 are cooled while tightly contacting the surface of the lower hot plate 26A. As a result, the surface of the bonded part 2x can serve as the smooth surface 2a. The surfaces of the non-bonded parts 2y of the plate member 2 do not tightly contact the lower hot plate 26A when cooled. Accordingly, the melted thermoplastic resin in the non-bonded parts 2y will move on their surfaces. As a result, the surface of the non-bonded parts 2y can serve as the rough surface 2b.
The plastic laminated structure 1 which is produced in the aforementioned processes includes the smooth and rough surfaces 2a and 2b which are alternately formed on the main surface of the plate member in stripes as shown in a plan view of
The roughness of the surface of a measurement object is measured by a non-contact laser probe. The surface of the measurement object is probed by irradiation with a spot laser beam so that the dimensions (width and height) of the surface of the measurement object are measured.
As shown in
On the surface of the plastic laminated structure 1 which is produced by the aforementioned processes, the coating 31 is formed by the following primer-coating and finishing processes.
The sanding sealer 32A is applied in the first primer-coating process. In the process following to the first primer-coating process, a UV coating which can be cured by ultraviolet radiation is applied onto the surface of the sanding sealer 32A after the sanding sealer 32A is cured. After the UV coating is cured by ultraviolet radiation, the surface of the UV coating is ground smooth. The UV coating is ground by a brush sander. Subsequently, the base color paint 32B is applied thick by a flow rotor, and almost completely eliminate the primer or original color, in other words, the main surface of the plate member 2 is colored white in the second primer-coating process. After the base color paint 32B is cured, a UV coating is additionally applied onto the surface of the base color paint 32B in the process subsequent to the second primer-coating process. After the UV coating is cured by ultraviolet radiation, the surface of UV coating is ground smooth.
After the surface of the plastic laminated structure 1 is colored in the primer coat process, the transparent finishing coating material 33 is applied onto the main surface of the plate member 2. The transparent finishing coating material 33 is applied by a roll coater in the finishing process. In the finishing process, a urethane, polyester, or acrylic group coating material is applied as the coating material 33. After this coating material is cured, a transparent UV coating (not shown) is applied onto the surface of the finishing coating material 33 in the process following to the finishing process. A urethane group UV coating is used as the ultraviolet curing coating, for example.
The plastic laminated structure 1 which is produced by the aforementioned processes can be lightweight but has high flexural rigidity, and can firmly hold the coating 31 which is fixed on the main surface of the plate member by the anchoring effect of the rough surfaces 2b in the main surface of the plate member. The surface of the plate member of the aforementioned plastic laminated structure 1 can have smooth surface which can provide good appearance. In addition, the plate member does not peel off even after repeatedly bent between a flat state and a bent state in which the plastic laminated structure is bent at a 90° angle in radius of curvature 1 cm 1000 times. That is, the plastic laminated structure has high bonding strength which can prevent the plate member from peeling off even after this 1000-time bending test. Additionally, the plastic laminated structure can have one-ninth of the weight of high tensile steel with thickness of 0.65 mm which can be used for vehicle body sheet steel and flexural rigidity seven times higher than the high tensile steel.
The plastic laminated structure 1 shown in
The plate member 2 and the core member 3 are placed on one another and thermally bonded to each other by heating them by a pair of bonding plates 21 as shown in
The bonded parts 2x to which the bonded portions 3A of the core member 3 are thermally bonded, and the non-bonded parts 2y to which the core member 3 is thermally not bonded are alternately arranged in stripes on the plate member 2. After the core member 3 is thermally bonded to the back surface, the bonded parts 2x of the plate member 2 are formed by melting the thermoplastic resin of the plate member 2 as the rough surface 2b which has very small asperities. In the non-bonded parts 2y of the plate member 2, because the core member 3 is not thermally bonded to the back surface of the plate member 2, the melting of the thermoplastic resin of the plate member 2 is limited so that such asperities are not formed and the smooth surface 2a is formed.
The plastic laminated structure 1 which is produced in the aforementioned processes includes the smooth and rough surfaces 2a and 2b which are alternately formed on the surface of the plate member in stripes as shown in a perspective view of
These graphs show that the smooth surface 2a is formed in the non-bonded part 2y, and the rough surface 2b having larger roughness than the smooth surface 2a is formed in the bonded part 2x on the plate member surface. As shown in
On the surface of the plastic laminated structure 1 which is produced by the aforementioned processes, the coating 31 is formed similar to the example 1. Similar to the example 1, the plastic laminated structure 1 which is produced by the aforementioned processes can be lightweight but has high flexural rigidity, and can firmly hold the coating 31 which is fixed on the surface of the plate member by the anchoring effect of the rough surfaces 2b in the surface of the plate member.
The plastic laminated structure according to the present invention which includes the smooth and rough surfaces arranged on its surface can be effectively used for vehicle body sheet steel, mobile phone cases, and the like as a plastic laminated structure which can firmly hold a surface treatment layer on its surface whereby preventing the surface treatment layer from peeling off instead of metal plate.
It should be apparent to those with an ordinary skill in the art that while various preferred embodiments of the invention have been shown and described, it is contemplated that the invention is not limited to the particular embodiments disclosed, which are deemed to be merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention, and which are suitable for all modifications and changes falling within the scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-202329 | Oct 2018 | JP | national |
| 2018-202330 | Oct 2018 | JP | national |
