JP2019000904A - Laser processing method for carbon fiber-reinforced composite-laminated sheet, and laser-processed carbon fiber-reinforced composite-laminated sheet - Google Patents

Abstract

To provide a laser processing method for obtaining a carbon fiber-reinforced composite-laminated sheet excellent in reliability by improving a processing cost, processing quality and labor environment, and to provide the laser-processed carbon fiber-reinforced composite-laminated sheet.SOLUTION: There is provided a laser processing method for a carbon fiber-reinforced composite-laminated sheet characterized by irradiating an outermost surface on the flexible board of that sheet with a carbon dioxide gas laser focusing on the surface to cut or bore, and also there is provided the above sheet characterized by processing through the method.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a laser processing method using a carbon dioxide laser of a carbon fiber reinforced composite laminate sheet, and a carbon fiber reinforced composite laminate sheet processed by this method. More specifically, a carbon fiber reinforced composite laminated sheet obtained by integrally molding a carbon fiber sheet impregnated with resin between two flexible boards, or a carbon fiber sheet impregnated with resin and one flexible board The present invention relates to a laser processing method for cutting or punching a carbon fiber reinforced composite laminated sheet integrally formed by bonding carbon dioxide using a carbon dioxide laser, and a carbon fiber reinforced composite laminated sheet processed by this method.

  Aged deterioration due to material and structural factors of existing concrete structures will cause corrosion of internal reinforcing bars and cross-sectional defects, etc., where cracks have occurred, and the structural strength will be reduced, so it is necessary to reinforce depending on the state Various reinforcing methods have been developed (Patent Document 1). For example, a steel plate winding method, a carbon fiber sheet winding method, a concrete thickening method, and the like can be given.

  The steel plate winding method is a method in which a steel plate is installed outside an existing concrete structure, and a cement-based high-strength non-shrink mortar is filled in the gap between the existing concrete structure and the steel plate to integrate them. The carbon fiber sheet winding method is a method in which the surface of an existing concrete structure is smoothed, and then the carbon fiber sheet is adhered with an epoxy resin. In the concrete augmentation thickening method, after smoothing the surface of the existing concrete structure, a formwork is placed on the surface of the existing concrete structure, and reinforcing bars and concrete are placed in the gap between the existing concrete structure and the formwork. It is an integrated method.

  However, each of these reinforcing methods has the following problems. The steel plate winding method uses heavy and easily rusted steel plates, so the workability is poor, rust prevention measures are required, maintenance for about 5 years is required, and measures against fire in welding between steel plates during construction are also required It is. In addition, there is also a problem that quality variation due to welding is a concern. Moreover, in the carbon fiber sheet winding method, there is a problem that the carbon fiber sheet has a high risk of peeling after the construction unless the surface treatment of the surface of the existing concrete structure is performed carefully. In the thick concrete method, thick reinforced concrete is placed outside the existing concrete structure, so the structure becomes heavy and the foundation of the existing concrete structure needs to be reinforced. There is a problem that a thermal stress due to the heat of hydration of the cement occurs between the reinforced concrete and a crack after the construction.

  Therefore, it is a method to solve the problems of these reinforcing methods, ensuring the desired structural strength, without the occurrence of rust and peeling, etc., can maintain good quality after construction, and has excellent workability Reinforcing methods for existing concrete structures have been developed.

  As shown in FIG. 1, this reinforcing method for an existing concrete structure is characterized by using a carbon fiber reinforced composite laminated sheet A, and is roughly classified into two types. One is a carbon fiber reinforced composite laminated sheet A-1 in which a carbon fiber sheet 2 impregnated with a resin is sandwiched between two flexible boards 1, and one is a carbon fiber sheet impregnated with a resin. 2 and the flexible board 1 are carbon fiber reinforced composite laminate sheets A-2. Here, the adhesive layer 3 may be shared with the resin to be impregnated, or may be an adhesive different from the resin to be impregnated.

  The flexible board 1 is characterized by using cement and organic fibers (pulp) as main raw materials, and is a product obtained by papermaking and high-pressure press molding using these, followed by high-temperature and high-pressure steam curing. Among the fiber reinforced cement boards defined in JIS A 5430, this is the highest grade flame-retardant slate board having high strength and toughness and excellent impact resistance, and has a higher specific gravity than other slate boards.

  The carbon fiber sheet 2 is a carbon such as a unidirectional sheet in which polyacrylonitrile-based, pitch-based, and rayon-based carbon fibers are oriented and laminated in a single direction, or a bi-directional sheet in which a single oriented sheet is laminated in a cross shape. A fiber sheet is impregnated with an epoxy resin, and its cured product is so-called CFRP (Carbon Fiber Reinforced Plastic). Although this cured product has a specific gravity of about 1/4 compared with iron, the cured product has a tensile strength of about 5 to 6 times and exhibits a structural strength equal to or greater than that of reinforced concrete in a thin film.

  The carbon fiber reinforced composite laminated sheet A-1 is flexible by superimposing a predetermined number of carbon fiber sheets having a basis weight (weight of carbon fibers per unit area) and an orientation form according to the application in a predetermined direction. After being laminated on the board 1 and impregnated with an epoxy resin adhesive or the like, the carbon fiber sheet 2 is sandwiched and cured by another flexible board 1 to be joined and integrated. Alternatively, the carbon fiber sheet 2 obtained by impregnating the carbon fiber sheet with an epoxy resin or the like to be cured or semi-cured is an epoxy resin system, a vinyl acetate resin system, an EVA (ethylene-vinyl acetate copolymer) resin system, Acrylic resin, chloroprene rubber, styrene / butadiene rubber, or other rubber, cement, gypsum, etc. are used to sandwich the two flexible boards 1 and are firmly joined and integrated. On the other hand, the carbon fiber reinforced composite laminate sheet A-2 is superposed on the carbon fiber sheet in the same manner, laminated on the flexible board 1, impregnated with an epoxy resin adhesive, etc., cured, and joined and integrated. Alternatively, the carbon fiber sheet 2 that has been cured or semi-cured by impregnating the carbon fiber sheet with an epoxy resin or the like is adhered to the flexible board 1 with the adhesive and firmly joined and integrated. However, for the sake of convenience, the adhesive layer 3 of the carbon fiber reinforced composite laminate sheet A in FIG. 1 may be the same as or different from the resin to be impregnated, but is not drawn separately.

  The reinforcement of the existing concrete structure using such a carbon fiber reinforced composite laminate sheet A mainly includes a method using a filler, a method using an adhesive, and a method using a filler or an adhesive and an anchor bolt in combination. is there. In the method using a filler, a carbon fiber reinforced composite laminated sheet A is disposed at a distance of 10 to 15 mm from the surface of an existing concrete structure, and an ultra-high strength cement, an expansion material and a high-performance water reducing agent are placed in the gap between the two. Filled with fillers mixed as main raw materials, or fillers made mainly of polymer materials such as epoxy resin, EVA resin, vinyl acetate resin, rubber, silicone, etc. It is a method to do. The method using an adhesive is a method of applying an adhesive such as an epoxy resin to one side of the carbon fiber reinforced composite laminate sheet A and integrating the carbon fiber reinforced composite laminate sheet A and the existing concrete structure. Moreover, the method of using a filler material or an adhesive agent and an anchor bolt together inserts a predetermined number of anchor bolts from the carbon fiber reinforced composite laminated sheet A side joined to the existing concrete structure by the filler or the adhesive agent. It is a method of integrating.

  Thus, in order to reinforce an existing concrete structure using the carbon fiber reinforced composite laminate sheet A, the carbon fiber reinforced composite laminate sheet A is formed according to the size and shape of the reinforcing portion, and the size of the anchor bolt. It needs to be molded according to the sheath shape. However, as can be seen from the configuration of the carbon fiber reinforced composite laminate sheet A, unlike the resin processing method such as injection molding, the size and shape can be controlled at the time of producing the carbon fiber reinforced composite laminate sheet A. However, after manufacturing the carbon fiber reinforced composite laminated sheet A having a relatively large area in advance, processing such as cutting and punching must be performed.

  Conventionally, such a material containing CFRP and CFRP is machined by a tool in which a cemented carbide chip or diamond is brazed, for example, machining using a running saw or a router, or abrasive particles are added to a water jet. Cutting or drilling has been performed by mixed abrasive jet machining or the like.

  However, CFRP is made of a hydrophobic carbon fiber fabric with excellent rigidity, which is embedded in a resin having viscoelasticity and hydrophilicity, and has different mechanical and chemical properties. The material is a laminated and compounded material. Therefore, although it has a structural strength equal to or better than that of reinforced concrete with a thin film, there are various problems in its machining and water jet machining (Patent Documents 2 to 6).

  First, there is a problem in processing quality that the carbon fibers constituting the woven fabric in the processed cross section are loosened and burrs, and it is difficult to accurately cut and punch the curve. Secondly, there is a problem that the tool brazed with the cemented carbide tip or diamond is severely worn, the processing speed is slow, and the processing cost is high. Third, there is a problem in the working environment that the scattering of carbon fibers during processing adversely affects the human body.

  The first problem is mainly due to the rigidity of the carbon fiber, and the second and third problems are due to the lack of interaction between the dissimilar materials inherently possessed by the composite material.

  This lack of interaction between dissimilar materials is due to the fact that CFRP has a long contact angle with water of about 90 ° and is a hydrophobic carbon fiber sheet that is known to be hydrophobic (non-patented). This is based on the fact that it is a composite material impregnated with an epoxy resin (Patent Document 7) having a large number of hydroxyl groups, a contact angle of water of about 60 °, and known to be hydrophilic in Document 1). . Therefore, in order to improve the convergence of the carbon fiber and improve the adhesiveness with the epoxy resin, the sizing agent is applied to the carbon fiber (Non-patent Documents 2 and 3), plasma treatment (Non-patent Document 1), and the like. However, since machining and jet machining tend to cause interface failure between the two, the above-mentioned problems in machining quality and working environment have arisen.

  Then, the processing of the material containing CFRP and CFRP is actively being studied instead of machining and jet processing (Patent Documents 2 to 6).

  However, there are the following problems in processing of CFRP and materials containing CFRP by laser processing. Conventionally, laser processing using an infrared laser such as a carbon dioxide laser is often used with a pulse width of more than milliseconds, and the laser light absorbed by the material is used as heat. Because it is converted to heat processing that performs melt processing with its thermal energy, the heat damage to the material is large, and the carbon fiber plays a role of heat conduction path, expanding the heat damage around the processing part (patent Reference 6). Therefore, carbonization of the epoxy resin, peeling between the CFRP layers of the processed material, peeling between the carbon fiber and the epoxy resin, and expansion of those areas cannot perform high quality processing (Patent Document 2). This reduces the mechanical properties of the processed material (Non-Patent Document 4). For example, it has been reported that the mechanical properties of CFRP cut with a carbon dioxide laser having a pulse width of the order of microseconds are inferior to CFRP cut by milling, which is a kind of machining (non-patent) Reference 4).

  Therefore, processing using nanosecond, picosecond, or femtosecond ultrashort pulse laser light has attracted attention as a processing method for composite materials such as CFRP and metals, and various ultrashort pulse laser beams. (Patent Documents 3 to 5). This is because the ultrashort pulse laser beam has a large peak output and energy density, and the pulse duration is shorter than the heat conduction time. Therefore, when the material is irradiated, only the vicinity of the irradiation point is instantaneously 8000 ° C. It is said that non-thermal processing, i.e., ablation processing can be performed without causing heat damage due to heating, melting, decomposition, and evaporation, almost no heat transfer to the periphery of the processed part. Because.

  However, in the case of ablation processing, there is a problem of processing cost. The ultrashort pulse laser used in ablation processing is a solid laser with a shorter wavelength than the carbon dioxide laser, etc., and the peak output and energy density are large, but the average output is smaller than the carbon dioxide laser etc. Ablation processing using a laser is more expensive than thermal processing using a carbon dioxide laser (Non-Patent Document 5). Also, with respect to the processing time (tact time), the ablation processing using an ultrashort pulse laser is longer than the thermal processing using a carbon dioxide laser, which increases the processing cost. As a solution, if the tact time in ablation processing is simply improved, thermal damage similar to that in thermal processing will occur, and there is a contradiction that is difficult to solve for the tact time of laser processing (Non-patent Document 6). . Thus, there is a problem that the cost of laser processing increases in the order of ultrashort pulse laser> solid laser> infrared laser in proportion to quality (Non-patent Documents 6 and 7).

  Furthermore, there is a problem of matching between the laser beam and the material. As described above, processing such as cutting and drilling with a laser beam is basically performed through a process of melting, decomposition, and evaporation, where the laser beam absorbed by the material is converted into heat. Since the characteristic, that is, the wavelength region absorbed by the material is different, it is necessary to select a laser beam having a wavelength that is well absorbed by the material (Non-Patent Document 7). In particular, thermal processing using a carbon dioxide laser or the like has a low absorption rate of laser light, but the total energy of the irradiated laser light is large, whereas ablation processing using an ultrashort pulse laser has peak output and Although the energy density is large, the total energy of the irradiated laser is small, so that laser light having a wavelength that matches the light absorption characteristics of the material is required. Therefore, since composite materials made of various different materials such as CFRP have different light absorption characteristics depending on the components, ablation processing using laser light having a wavelength corresponding to the material must be performed.

  However, reports on the processing of CFRP and other composite materials using ultrashort pulse lasers with good results are focused only on the laser irradiation conditions, and the components of the used composite materials are unclear. Therefore, it is considered that studies on composite materials having various components and configurations have not been made (Patent Documents 3 to 5, and Non-Patent Documents 8 and 9).

  Therefore, it is considered that the laser processing technology related to the composite material is difficult to achieve both processing quality and processing cost, and no universal laser processing technology has been established for any composite material.

  Under such circumstances, the carbon fiber reinforced composite laminated sheet A used as a reinforcing material for the above-described existing concrete structure has been conventionally cut and punched by machining. The carbon fiber reinforced composite laminate sheet A includes a plurality of carbon fiber sheets 2 in which a carbon fiber sheet is impregnated with an epoxy resin, and a flexible board 1 mainly composed of cement and organic fibers (pulp). The carbon fiber reinforced composite laminated sheet A used as a reinforcing material for an existing concrete structure is a structure in which the epoxy resin-based adhesive 3 is firmly joined and integrated. This is because the problem of material reliability is the most important factor, and the current situation is still relying on proven machining. However, laser processing is required because of processing quality, processing cost, and working environment.

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  Conventionally, carbon fiber sheets impregnated with epoxy resin, used as a reinforcing material for existing concrete structures, are integrally molded by sandwiching carbon fiber sheets impregnated with two flexible boards, or impregnated with epoxy resin. Carbon fiber reinforced composite laminated sheets that are integrally molded by bonding a carbon fiber sheet and a flexible board have been processed by cutting, drilling, etc. by machine processing such as running saws and routers with proven track records. .

  However, first, there is a problem in processing quality that the carbon fibers constituting the fabric in the processed cross section are loosened and burrs, and it is difficult to cut and punch the curve accurately. Secondly, there is a problem in machining cost that the tool brazed with the carbide tip or diamond is severely worn and the machining speed is slow. Third, there is a problem in the working environment that the scattering of carbon fibers during processing adversely affects the human body.

  On the other hand, application of laser processing technology to composite materials has recently been started mainly with CFRP, and establishment of damage evaluation technology from the viewpoint of reliability is being demanded (Non-Patent Document 5). In particular, carbon fiber reinforced composite laminated sheets used as reinforcing materials for existing concrete structures are based on proven machining, because reliability is the most important factor, and the mechanical properties of the reinforcing materials Processing using a carbon dioxide laser that may have an adverse effect has not yet been studied.

  In addition, the ultra short pulse laser processing that solves the problem of thermal damage caused by carbon dioxide laser processing has the problem of processing costs that the equipment is expensive and the tact time is long, and the carbon fiber is reinforced. It has never been applied to the processing of composite laminate sheets, nor does it completely wipe out reliability issues.

  The present invention relates to a carbon fiber reinforced composite laminate sheet used as a reinforcing material for an existing concrete structure, which has solved the above-mentioned various problems, improved processing quality, processing cost, and working environment, and processed carbon It is an object of the present invention to provide a laser processing method capable of providing a carbon fiber reinforced composite laminate sheet excellent in reliability of the fiber reinforced composite laminate sheet and a carbon fiber reinforced composite laminate sheet processed by the method.

  The present inventors integrally formed a carbon fiber sheet impregnated with an epoxy-based resin, which is used as a reinforcing material for an existing concrete structure, with two flexible boards mainly composed of cement and organic fibers (pulp). The mechanical properties of a tensile strength test piece obtained by cutting a carbon fiber reinforced composite laminate sheet with a carbon dioxide laser are superior to those of a tensile strength test piece obtained by cutting the same carbon fiber reinforced composite laminate sheet with a running saw. As a result, the present invention has been completed.

  That is, the present invention is a carbon fiber reinforced composite laminate sheet, which is used as a reinforcing material for an existing concrete structure and is integrally formed by sandwiching a carbon fiber sheet impregnated with an epoxy resin between two flexible boards, or an epoxy When processing a carbon fiber reinforced composite laminated sheet made by bonding a carbon fiber sheet impregnated with resin and a single flexible board, using a carbon dioxide laser, the carbon dioxide laser is focused on the flexible board and carbon dioxide is focused. A laser processing method of a carbon fiber reinforced composite laminate sheet, characterized by irradiating a gas laser and cutting or punching. More preferably, it is a laser processing method of a carbon fiber reinforced composite laminate sheet characterized by irradiating a carbon dioxide laser with the carbon dioxide laser focused on the outermost surface of the flexible board, and cutting or punching.

  In addition, the present invention is a carbon fiber reinforced composite laminated sheet having excellent mechanical properties, characterized by being cut or punched by the laser processing method.

  The carbon fiber reinforced composite laminate sheet cut or punched in the present invention is impregnated with the carbon fiber sheet 2 impregnated with an epoxy resin or the like, as shown in the carbon fiber reinforced composite laminate sheet A-1 in FIG. An epoxy system in which an epoxy resin or the like is formed as an adhesive layer 3 and is sandwiched between two flexible boards 1 or an epoxy system in which a carbon fiber sheet 2 impregnated with an epoxy resin or the like and cured or semi-cured is impregnated. Any of the structures in which an adhesive layer that is the same as or different from the resin forms the adhesive layer 3 and is sandwiched between the two flexible boards 1 may be used. Moreover, the carbon fiber reinforced composite laminate sheet cut or perforated in the present invention has a carbon fiber sheet 2 impregnated with an epoxy-based resin or the like, as shown in carbon fiber reinforced composite laminate sheet A-2 in FIG. An epoxy resin impregnated with a structure in which an epoxy resin or the like to be impregnated is formed as an adhesive layer 3 and bonded to a single flexible board 1 or a carbon fiber sheet 2 impregnated with a resin or the like and cured or semi-cured. Any of the configurations in which the same or different adhesive as that of the system resin forms the adhesive layer 3 and is bonded to the single flexible board 1 may be used.

  The flexible board 1 is a product made of cement and organic fibers (pulp) as main raw materials, made into paper, and subjected to high pressure press molding after paper making and high pressure press molding. Among the fiber reinforced cement boards defined in JIS A 5430, the high-grade flame-retardant slate has a high specific gravity of about 1.6 compared to other slate boards with high strength and toughness and excellent impact resistance. A board is preferred. In particular, as a raw material, a flexible board containing 35 to 45% by weight of ordinary Portland cement, 30 to 40% by weight of a siliceous raw material, 5 to 8% by weight of an organic fiber, and 15 to 20% by weight of an inorganic admixture is more preferable. Flexible board N manufactured by Aikatec Building Materials Co., Ltd., flexible sheet N manufactured by Nozawa Co., Ltd., self-rex manufactured by A & A Material Co., Ltd., Chiyoda Sera Flexible Co., Ltd. manufactured by Chiyoda Sera Co., Ltd. .

  The carbon fiber sheet 2 is a unidirectional sheet obtained by orienting and laminating strands of carbon fiber strands (filaments) in a single direction, or two directions in which a mono-orientated sheet is laminated in a cross shape. A carbon fiber sheet such as a sheet impregnated with an epoxy resin or the like is preferably used.

  As the carbon fiber filament, any of polyacrylonitrile, pitch, and rayon carbon fibers can be used. However, sizing treatment or plasma treatment for improving the adhesive strength with the impregnated epoxy resin is performed. The ones made are preferred. In particular, the polyacrylonitrile is preferable as the carbon fiber, and the sizing treatment is preferably performed using a low molecular epoxy resin or a low molecular vinyl ester resin as the sizing agent.

In addition, in order to maintain the shape of the carbon fiber sheet, a cloth type in which glass fibers and the like are woven so as to be orthogonal to the carbon fiber strands and glass fibers orthogonal to both surfaces of the sheet are fused. There is a type that is a double-sided mesh and is not limited. The basis weight of the carbon fiber sheet is 200 to 1800 g / m ² , preferably 200 to 1200 g / m ² , more preferably 200 to 600 g / m ² . Typical carbon fiber sheets before impregnation with epoxy resin, etc. are FF sheets manufactured by Maeda Kosen Co., Ltd., Torayca (registered trademark) cloth manufactured by Toray Industries, Inc., manufactured by Nippon Steel & Sumikin Materials Co., Ltd. FORCA tow sheet FTS-C series, Mitsubishi Chemical Infrastructure Tech Co., Ltd. Repeller (registered trademark) MRK series, Mitsubishi Chemical Co., Ltd. Palofil (registered trademark) carbon fiber cloth, and the like can be used.

  The epoxy resin impregnated in the carbon fiber sheet is a two-part curable epoxy resin in which the main agent is an epoxy resin and the curing agent is an amine, the main agent is an epoxy resin, and the curing agent is an acid anhydride. A thermosetting epoxy resin which is a tertiary amine can be used. However, it is excellent in various physical properties such as the mechanical properties of the cured product and processability such as cutting, the curing conditions are mild, the main component is an epoxy resin, and the curing agent is an amine. Preferably used.

  As the epoxy resin constituting this two-component curable epoxy resin, bisphenol epoxy resin, phenol epoxy resin, polyglycol epoxy resin, ester epoxy resin, etc. can be used, but on the physical properties of the cured product, Bisphenol epoxy resins, particularly bisphenol A type epoxy resins, bisphenol F type epoxy resins, and mixtures of bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferred. Specifically, CF bond main agent manufactured by Arteco Co., Ltd., 2000 series such as Three Bond 2022 and 2023 manufactured by Three Bond Co., Ltd., main components of 2080 series such as 2081, 2083, 2086, and 2088, Mitsubishi Chemical Corporation Various jER (registered trademark) epoxy resins and the like can be used alone or in combination of two or more.

  On the other hand, as the amines, any of primary, secondary, or tertiary amines or polyamines can be used, and two or more of these can be used in combination. These amines may be aliphatic amines or aromatic amines. Furthermore, in order to improve and adjust the physical properties, volatility, compatibility with epoxy resins, curing speed, toxicity, etc. of the cured product, these amines have a large molecular weight glycidyl ether, phenyl glycidyl ether, and A modified amine or modified polyamine added with an epoxy compound or the like, or a modified amine or modified polyamine added with cyanoethyl, boron fluoride or the like can also be used. In particular, a modified aliphatic polyamine is preferable in view of physical properties. Specifically, CF bond curing agent manufactured by Arteco Co., Ltd., 3Bond Co., Ltd. Three Bond 2102, 2103, 2105, 2106, 2107, 2163, 2131 series, etc. 2100 series, Mitsubishi Chemical Co., Ltd. jER cure (Registered trademark) T, T0184, U, 113, and various jER cure (registered trademark) series such as W can be used alone or in combination of two or more.

  Such an epoxy resin impregnates a carbon fiber sheet and forms an adhesive layer 3 with the flexible board 1. The carbon fiber sheet is impregnated with an epoxy resin and cured or semi-cured carbon. It is also used as an adhesive layer 3 for the fiber sheet 2 and the flexible sheet. In addition, these compounding ratios are appropriately determined depending on the combination of the epoxy resin and amines.

And the double-sided flexible board type A-1 of the carbon fiber reinforced composite laminated sheet A to be subjected to the laser processing of the present invention is a unidirectional sheet oriented or laminated in a single direction, or a single oriented sheet in a cross shape Laminated two-way sheets, carbon fiber sheets having a basis weight of 200 to 600 g / m ² , are laminated on a single flexible board 1 by superposing them in a predetermined number and a predetermined direction according to applications. Then, after impregnating the two-component curable epoxy resin whose main agent is an epoxy resin and the curing agent is an amine, the two-component curable epoxy resin is cured by being sandwiched by another flexible board 1 The carbon fiber sheet 2 and the flexible board 1 are manufactured by being firmly joined and integrated. A carbon fiber sheet 2 impregnated, cured or semi-cured with an epoxy resin is prepared in advance, and a predetermined number of sheets and a predetermined direction are superposed on each other, and two flexible boards using a two-component curable epoxy resin. However, from the viewpoint of adhesiveness, it is preferable to integrally bond them as described above.

  Similarly, for a single-sided flexible board, a two-component curable epoxy resin in which the carbon fiber sheets of the above carbon fibers are superimposed and laminated on the flexible board 1, the main agent is an epoxy resin, and the curing agent is an amine. Then, the carbon fiber sheet 2 and the flexible board 1 are firmly joined and integrated by curing the two-component curable epoxy resin. A carbon fiber sheet 2 impregnated, cured, or semi-cured with an epoxy resin is prepared in advance, and a predetermined number of sheets and a predetermined direction are superposed, and bonded to the flexible board 1 using a two-component curable epoxy resin. However, from the viewpoint of adhesiveness, it is preferable to integrally bond as described above.

  The laser processing method for cutting or punching the carbon fiber reinforced composite laminated sheet A of the present invention uses a carbon dioxide gas laser with a low-cost apparatus, a short tact time, and a low processing cost. 1 and is particularly effective for the carbon fiber reinforced composite laminated sheet A used as a reinforcing material for an existing concrete structure. Furthermore, it is more preferable to set the focal point of the laser beam to the outermost surface of the flexible board 1. The reason why such a carbon dioxide laser processing method is effective is that the carbon fiber reinforced composite laminated sheet A has a carbon fiber sheet impregnated with a plurality of carbon fiber sheets impregnated with an epoxy resin in a predetermined direction, From both sides, it is a structure in which cement and organic fiber (pulp) are sandwiched between flexible boards 1 made mainly of raw materials, and each is firmly joined and integrated with an epoxy resin adhesive, which is more complicated than CFRP. It is thought to be related to material and structure. That is, by setting the focal point of the carbon dioxide laser to the flexible board or its outermost surface, it is possible to prevent thermal damage to the carbon fiber sheet 2 that is the CFRP of the carbon dioxide laser, and the heat transmitted through the carbon fiber as a path, It is considered that the expansion of thermal damage around the processed part could be reduced. Therefore, the physical properties of the epoxy resin can be obtained without causing carbonization of the epoxy resin, delamination separation between the flexible board 1 and the carbon fiber sheet 2, delamination between the carbon fiber and the epoxy resin, and enlargement of those regions. As a result, high quality processing can be performed. In terms of appearance, there is no loosening or burring of the carbon fibers that make up the fabric in the processed cross section, and the cutting and drilling of curves can be performed accurately, and the scattering of carbon fibers during processing adversely affects the human body. The problem was also solved. In terms of physical properties, it has become possible to supply processed products with stable material reliability (mechanical properties) required for the carbon fiber reinforced composite laminated sheet A used as a reinforcing material for existing concrete structures.

  In order to perform processing with a carbon dioxide laser such as cutting and drilling with higher quality in terms of appearance and physical properties, it is desirable to control the oscillation mode and irradiation conditions of the carbon dioxide laser as follows. First, the oscillation mode is preferably normal pulse oscillation with a pulse width of 5 to 10 μs. Second, the output is preferably 300 to 500W. Third, the repetitive driving frequency is preferably 50,000 to 100,000 Hz. Fourth, the spot diameter is preferably 50 to 300 μm. Fifth, the plotter speed is preferably 50 to 100 cm / min. If it is set above these upper limit values, thermal damage of the carbon dioxide laser starts to occur, and if it is set below these lower limit values, there arises a problem that the processing speed such as cutting and drilling becomes slow.

  Such an oscillation mode and irradiation condition of the carbon dioxide gas are important elements along with focusing the laser beam on the flexible board 1. Conventionally, a carbon dioxide laser is generally used with a pulse width of more than milliseconds, and the laser light absorbed by the material is converted into heat, which is a heat processing that performs melting processing with the heat energy. In addition to the large heat damage, the carbon fiber played a role of a heat conduction path, and it was a factor to expand the heat damage around the processed part. In addition to using a carbon dioxide laser with a pulse width of the order of microseconds, the output, repetition drive frequency, spot diameter, and plotter speed described above have the same effect as ablation processing using an ultrashort pulse laser. Although it is a carbon dioxide laser, it is considered that thermal damage could be reduced without increasing the tact time.

  The carbon dioxide laser processing apparatus is not particularly limited, and the work area is wide, pattern irradiation is possible, and the XY axis direction in the working area is freely moved based on the input data. Anything that can be cut and drilled is acceptable. Specific carbon dioxide laser processing devices include SmartDIYs Smart Laser CO2, Universal Laser Systems VLS series, PLS series, ILS series, PLS6MW, Trotec Speedy series, SP series, and GS series, Examples include various Epilog Laser manufactured by Epilog and various LaserLife, LS series manufactured by Gravograph, LaserPro (registered trademark) series manufactured by GCC, and XY series manufactured by SEI. Among them, Universal Laser Systems ILS series and PLS6MW, Trotec GS series, Epilog LaserLife CBF series, CSH series, LCR series, LCG series, LCI series CSE series and LEW series, Gravograph LS1000Xp, and SEI MERCURY609 series are preferred.

  According to the present invention, cutting or drilling with excellent quality of the carbon fiber reinforced composite laminated sheet A can be performed using a carbon dioxide laser with a low-cost apparatus, a short tact time, and a low processing cost. . In particular, the carbon fiber reinforced composite laminate sheet A used as a reinforcing material for an existing concrete structure can be prevented from being damaged by heat with respect to the carbon fiber sheet 2 which is a CFRP of a carbon dioxide laser by using a carbon fiber. The heat transmitted through the path could reduce the expansion of thermal damage around the processed part. Therefore, the appearance and physical properties of the resin can be eliminated without causing carbonization of the epoxy resin, delamination between the flexible board 1 and the carbon fiber sheet 2, delamination between the carbon fiber and the epoxy resin, and expansion of those areas. Can also be processed with high quality. In terms of appearance, there is no loosening or burring of the carbon fibers that make up the fabric in the processing cross-sections recognized by machining such as running saws and routers. We were able to solve the problem of the working environment in which the scattering of fibers adversely affected the human body. In terms of physical properties, it has become possible to significantly improve the material reliability (mechanical characteristics) of processed products that have been cut and drilled by conventional machining such as running saws and routers. .

It is a cross-sectional schematic diagram which shows the structure of the carbon fiber reinforced composite laminated sheet used by this invention. It is a cross-sectional schematic diagram which shows the processing method of the carbon dioxide laser of the carbon fiber reinforced composite lamination sheet which is one Embodiment of this invention. It is the top view and sectional drawing which show the shape of the test piece used for the tensile strength test of a carbon fiber reinforced composite lamination sheet. It is a schematic diagram of the screw type tensile strength test system which evaluates the mechanical property (breaking strength) of a carbon fiber reinforced composite lamination sheet. 3 is a test force (load) -displacement (strain) curve for calculating mechanical properties (breaking strength) of a carbon fiber reinforced composite laminated sheet cut with a carbon dioxide gas laser having a pulse width of 960 μs. It is a test force (load) -displacement (strain) curve for calculating the mechanical property (breaking strength) of the carbon fiber reinforced composite laminated sheet cut by a carbon dioxide laser with a pulse width of 5 μs. It is the figure which showed the influence which the pulse width exerts on the mechanical characteristic (breaking strength) of the carbon fiber reinforced composite laminated sheet cut | disconnected by the carbon dioxide laser.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments. However, the present invention is not limited to the embodiments, and various modifications may be made without departing from the spirit of the present invention. However, the present invention is limited only by the technical idea described in the claims.

  The carbon fiber reinforced composite laminate sheet A processed using the carbon dioxide laser of the present invention was produced as follows.

The flexible board 1 uses 35 to 45% by mass of ordinary Portland cement, 30 to 40% by mass of a siliceous raw material, 5 to 8% by mass of organic fibers, and 15 to 20% by mass of an inorganic admixture as raw materials. After papermaking and high-pressure press molding, a flexible board N product (thickness: about 3 mm) manufactured by Nozawa Co., Ltd., which was cured at high temperature and high pressure steam was used. As the carbon fiber sheet, a unidirectional carbon fiber sheet FF-CR120-50-E manufactured by Maeda Kosen Co., Ltd. with a basis weight of 200 g / m ² was used. As the two-pack curable epoxy resin, bisphenol A type epoxy was used. A CF bond manufactured by Arteco Co., Ltd. using a mixture of a resin and a bisphenol F type epoxy resin as a main ingredient and a modified aliphatic polyamine as a curing agent was used.

  Then, using these materials, a sheet of carbon fiber is laminated on one flexible board 1, and a two-component curable epoxy resin is impregnated into the carbon fiber sheet. The two-component curable epoxy resin is cured and the carbon fiber sheet 2 and the flexible board 1 are joined and integrated to produce a double-sided flexible board type carbon fiber reinforced composite laminated sheet A-1. did. As a result, the thickness of the CFRP layer was about 1 mm.

  This carbon fiber reinforced composite laminated sheet A-1 was cut into the shape of a test piece used for the tensile strength test shown in FIG. 3 using MERCURY609NRG manufactured by SEI as a carbon dioxide laser device. For comparison, a running saw that was machined was used and cut into the shape of a test piece used in the tensile strength test shown in FIG.

  The carbon dioxide laser oscillation mode and conditions were set as follows and cut. The oscillation mode is normal pulse oscillation, and the maximum output, emission rate (P%), output, repetition drive frequency (F), spot diameter, and plotter speed are 467 W, 80%, 374 W, 500 to 100, respectively. 000 Hz, 155 μm, and 60 cm / min, and the conditions were set such that the pulse width (PW) was changed by the repetitive driving frequency (F), and the focal point was the position of the outermost surface 5 of the flexible board as shown in FIG. It cut | disconnected according to. The pulse width (PW) changed here was obtained by a relational expression based on the characteristics of the oscillation device of the carbon dioxide laser used in this example, PW = 0.6 × P / (100 × F). . Moreover, the cutting of the running saw performed for comparison was performed at a plotter speed corresponding to the cutting speed of the carbon dioxide laser. The physical properties of each cut specimen were measured at a tensile speed of 10 mm / min using a tensile strength tester.

  Here, the reason why the tensile strength test is adopted as a method for measuring physical properties of the cut specimen is that it is widely recognized as the most basic and reliable test method for measuring the strength of a material. In this test, a load when an elongation is given to a test piece as a displacement (strain) can be measured with respect to a continuously changing elongation. The schematic diagram of the tensile strength test system shown in FIG. 4 is particularly referred to as a screw type or Instron type tensile test system. A load cell 7 for detecting a load is provided on the upper part of the crosshead 6, and an upper test piece fixing chuck 8-1 is connected to the load cell 7 to hold the upper part of the tensile strength test piece C. On the other hand, the lower part of the tensile strength test piece C is gripped by the lower test piece fixing chuck 8-2. The crosshead 6 is moved up and down by rotating the screw rods on both sides (the screw rod on the right side is omitted in FIG. 4) by the servo motor 9, and the tensile strength test piece C is stretched at a constant speed. The load applied to the piece C is converted into an electric signal by the load cell and amplified. The elongation is amplified by converting the amount of rotation of the screw rod corresponding to the amount of movement of the crosshead 6 into an electrical signal. These electric signals are continuously input into the load-elongation curve, that is, FIG. 5A and FIG. 5A by inputting the load signal to the Y axis and the elongation signal to the X axis using the XY recorder 13. It can be recorded as a test force (load) -displacement (strain) curve as shown in (b), and the mechanical properties of the material against tension are evaluated from this test force (load) -displacement (strain) curve. . Here, as shown in FIG. 3, the tips of the upper test piece fixing chuck 8-1 and the lower test piece fixing chuck 8-2 are positioned at the positions (1) and (3) of the tensile strength test piece C. About what was grabbed and ruptured at the position (2), the rupture load per unit cross-sectional area was obtained from the measured value of the rupture load and the cross-sectional area of the tensile strength test piece C, and evaluated as the rupture strength, which is a mechanical characteristic.

As a representative example of the test force (load) -displacement (strain) curve of a test piece obtained as a result of a tensile test, FIG. 5A shows the test force of a test piece cut with a carbon dioxide laser having a pulse width of 960 μs. A (load) -displacement (strain) curve is shown in FIG. 5B, and a test force (load) -displacement (strain) curve of a test piece cut with a carbon dioxide laser having a pulse width of 5 μs is shown. And the analysis result of such a curve was put together in Table 1 including the analysis result of the curve obtained from the test piece cut | disconnected with the running saw. As can be seen from FIG. 5, the analysis results in Table 1 were conducted using ten test pieces, and the fracture load was actually measured from the seven test results broken in the region (2) of FIG. 3. The maximum and minimum values were deleted, and the breaking load per unit cross-sectional area was evaluated as the breaking strength, which is a mechanical property.

  Since carbon fiber reinforced composite laminate sheets that have been used in the past and are cut with a running saw are recognized as sufficiently reliable, a carbon fiber reinforced composite laminate sheet cut with a carbon dioxide laser is cut with a running saw. Whether the carbon dioxide laser processing method of the present invention is an effective method as a means for solving thermal damage, which has been a problem in the past, by comparing physical properties with the carbon fiber reinforced composite laminate sheet. Judgment can be made.

The standard deviation σ of the breaking strength of the tensile strength test piece C cut with a running saw is 23.2 N / mm ² , and 3σ is 68.2 N / mm ^2, which is 99.7% of the breaking strength of the tensile strength test piece C. That is, it has a mechanical property of 99.7% breaking strength of 425 N / mm ² or more. Therefore, if the standard deviation σ of the breaking strength of the tensile strength test piece C cut by the carbon dioxide laser is less than this and the 99.7% breaking strength is more than this, the problem of thermal damage of the carbon dioxide laser is solved. It can be regarded as having been able to.

As apparent from Table 1, the standard deviation σ and 3σ of breaking strength pulse width at 5μs and 10μs, respectively, it was 17.9N / mm ² and 22.4N / mm ^2, in the case of cutting along a running saw The breaking strength was more stable than the breaking strength. Even 99.7% breaking strength of these tensile strength test pieces C, respectively, 474N / mm ² or more, and showed 471N / mm ² or more. This shows that the laser processing of the present invention can be cut without causing physical damage to the carbon fiber reinforced composite laminated sheet A-1 as compared with the results of the running saw. That is, the thermal damage of the laser processing using a carbon dioxide laser makes the focal position of the carbon dioxide laser beam the outermost surface of the flexible board, and the oscillation form and irradiation conditions of the carbon dioxide laser, especially the pulse width is 5 to 5. It is considered that this can be achieved by controlling in the range of 10 μs.

  Further, as apparent from the result of the cut cross-sectional area in Table 1, since the thickness of the tensile strength test piece C is constant, the carbon dioxide gas is larger than the width of the tensile strength test piece C processed by the running saw. It can be seen that the tensile strength test piece C processed by laser has a uniform width and can be cut with high accuracy. In addition, from the visual observation of the cut surface, in the case of a running saw, the carbon fibers that make up the fabric are loosened and flashed, and the carbon fibers are scattered during processing. Was not recognized.

  The carbon fiber laser processing method of the carbon fiber reinforced composite laminate sheet of the present invention is also applied to processing methods such as cutting and punching of composite laminate sheets of carbon fiber sheets such as CFRP and organic or inorganic sheets other than flexible boards. It is possible to provide a processed product that can be applied and has little thermal damage caused by a carbon dioxide laser. It can also be applied to various composite materials that have been processed using a conventional carbon dioxide laser to reduce thermal damage. As a result, the carbon fiber reinforced composite laminate sheet produced by the carbon dioxide laser processing method of the present invention is highly reliable with uniform mechanical properties, and not only for reinforcing existing concrete structures, It can be used as a structure part.

A Carbon fiber reinforced composite laminated sheet A-1 Double-sided flexible board type A-2 Single-sided flexible board type 1 Flexible board 2 Carbon fiber sheet impregnated with resin 3 Adhesive layer 4 Carbon dioxide laser 5 Carbon dioxide laser focal point B Tensile Strength test system 6 Crosshead 7 Load cell 8-1 Upper test piece fixing chuck 8-2 Lower test piece fixing chuck 9 Servo motor 10 Screw rod 11 Amplifier 1
12 Amplifier 2
13 XY Recorder C Tensile strength test piece

Claims (7)

  A carbon fiber sheet impregnated with an epoxy resin, a carbon fiber reinforced composite laminated sheet integrally formed by sandwiching two flexible boards mainly composed of cement and organic fibers, or the carbon fiber sheet In processing using a carbon dioxide laser of a carbon fiber reinforced composite laminated sheet that is integrally formed by bonding with a single flexible board, the carbon dioxide laser is focused on the flexible board and irradiated with the carbon dioxide laser, and then cut. Alternatively, a laser processing method of a carbon fiber reinforced composite laminate sheet, wherein holes are formed.   2. The laser processing method according to claim 1, wherein the oscillation mode of the carbon dioxide laser is normal pulse oscillation and the pulse width is 5 to 10 μs.   The laser processing method according to claim 2, wherein an output of the carbon dioxide laser is 300 to 500 W.   4. The laser processing method according to claim 2, wherein the carbon dioxide laser has a repetition drive frequency of 50,000 to 100,000 Hz.   The laser processing method according to any one of claims 2 to 4, wherein a spot diameter of the carbon dioxide laser is 50 to 300 µm.   The laser processing method according to any one of claims 2 to 5, wherein a plotter speed of the carbon dioxide laser is 50 to 100 cm / min.   A carbon fiber reinforced composite laminate sheet cut or perforated by the laser processing method according to claim 1.

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