JP2019195914A - Molding method of fiber-reinforced molded article - Google Patents

Abstract

To provide a molding method of a fiber-reinforced molded article capable of enhancing strength of the molded article.SOLUTION: A preliminary molded article formed by heating and pressurizing a fiber-reinforced plastic material constituted by impregnating a fiber material with a thermoplastic resin is arranged at a die having a larger volume than a volume of the preliminary molded article. A primary molded article having a volume for filling a gap inside a molding space formed by closing the die in which the preliminary molded article is arranged, that is formed by heating and pressurizing the fiber-reinforced plastic material formed by impregnating the fiber material with the thermoplastic resin is heated into a softened state, and the preliminary molded article arranged inside the molding space is heated into a softened state. The primary molded article that has become a softening state is press-fitted into the molding space in which the softened preliminary molded article is arranged to pressure-mold a second molded article.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for molding a fiber reinforced molded product for molding a fiber reinforced plastic material constituted by impregnating a fiber material with a thermoplastic resin.

  The fiber reinforced plastic material is excellent in mechanical properties, light weight, corrosion resistance, and the like, and thus is widely deployed in various applications. Since the fiber reinforced plastic material is formed by impregnating a fiber material with a thermoplastic resin, the fiber reinforced plastic material is also advantageous in terms of molding and has attracted attention. For example, a method for forming a bolt, which is a fiber-reinforced molded product, has already been proposed using the fiber-reinforced plastic material. Specifically, a rod-like fiber reinforced plastic material having a volume smaller than the volume of the molding space of the mold is placed vertically in a mold having an internal thread formed on the inner surface. Next, after heating the fiber reinforced plastic material to a temperature equal to or higher than the softening point, the plunger is moved downward to press the fiber reinforced plastic material downward and bulge in the radial direction so that fibers are formed on the inner surface of the mold. By pressing the reinforced plastic material, a male screw is formed on the outer surface of the fiber reinforced plastic material to form a bolt (for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-4249

  In the configuration of Patent Document 1, the plunger is moved downward to press the fiber reinforced plastic material downward and bulge in the radial direction, so that sufficient pressure is applied to the fiber reinforced plastic material. Not only cannot be done, but also the distance between the fiber materials becomes wider than before molding, and there is a problem that the strength of the molded bolt (molded product) cannot be increased, and there is room for improvement.

  Then, this invention is made | formed in view of this situation, and makes it a subject to provide the shaping | molding method of the fiber reinforced molded product which can raise the intensity | strength of a molded product.

  The method for molding a fiber reinforced molded product according to the present invention includes a preform formed by heating and pressurizing a fiber reinforced plastic material formed by impregnating a fiber material with a thermoplastic resin. And having a volume that fills a gap in a molding space formed by closing the mold on which the preform is disposed, and a thermoplastic resin. A primary molded product formed by heating and pressurizing a fiber reinforced plastic material formed by impregnating a fiber material to be in a softened state by heating, and a preform formed in the molding space Is heated into a softened state, and the softened primary molded product is press-fitted into the molding space in which the preliminarily molded product in the softened state is arranged to press the secondary molded product Characterized by molding That.

  According to the present invention, the preform formed by heating and pressurizing the fiber reinforced plastic material can sufficiently impregnate the fiber material with the resin and remove bubbles in the resin. The strength of the molded product can be increased. In addition, the primary molded product formed by heating and pressurizing the fiber reinforced plastic material can sufficiently impregnate the fiber material with the resin and remove bubbles in the resin, similar to the preformed product. Therefore, the strength of the molded product can be increased. The preform and the primary molded product with increased strength are heated and softened, and the primary molded product in the softened state is placed in the molding space where the preformed product in the softened state is arranged. By press-fitting toward the end, it is possible to form the secondary molded product by integrating the preformed product and the primary molded product while applying pressure, so that the strength can be further increased. Moreover, the space | interval of the fiber materials of a secondary molded product does not become larger than the space | interval before shaping | molding.

  In the method for molding a fiber reinforced molded product according to the present invention, the primary molded product to be press-fitted may be supplied into the molding space through a flow path that is narrower toward the molding space side.

  As described above, since the primary molded product to be press-fitted is supplied into the molding space via the flow path that is narrower toward the molding space side, pressure can be applied to the primary molded product to be press-fitted. Can be sufficiently impregnated with resin, and bubbles in the resin can be removed.

  Further, in the method for molding a fiber reinforced molded product according to the present invention, an internal thread is formed on the inner surface of the mold forming the molding space, and the primary molded product to be press-fitted is an outer surface of the preformed product. A male screw may be formed as the secondary molded product by entering into the gap between the metal mold and the inner surface of the mold and being pressed against the female screw.

  As described above, the primary molded product to be press-fitted enters the gap between the outer surface of the preformed product and the inner surface of the mold and is pressed against the female screw, so that the male screw can be reliably formed as the secondary molded product.

  In the method for molding a fiber-reinforced molded product according to the present invention, the fiber volume content of the primary molded product may be set higher than the fiber volume content of the preformed product.

  As described above, in particular, by setting the fiber volume content of the primary molded part of the part where the screw requiring strength is formed higher than the fiber volume content of the preformed article, in terms of cost and strength Become advantageous.

  In the method for molding a fiber-reinforced molded product according to the present invention, the fiber material constituting the preform and the fiber material constituting the primary molded product may be composed of carbon fibers.

  As described above, the fiber material constituting the preform and the fiber material constituting the primary molded product are made of carbon fiber, so that the carbon fiber does not break during molding and reliably enters a narrow gap. Thus, it is possible to reliably suppress a decrease in strength.

  In the method for molding a fiber-reinforced molded product according to the present invention, the pressure when the primary molded product is press-fitted may be set to be equal to or lower than the pressure when the mold is clamped.

  As described above, if the pressure at the time of press-fitting the primary molded product is set to be equal to or lower than the pressure at the time of mold clamping, it prevents the mold from opening due to the pressure at the time of press-fitting the primary molded product. be able to. Thereby, it can suppress reliably that a burr | flash generate | occur | produces in a secondary molded product.

  As described above, according to the present invention, a preformed product formed by heating and pressurizing and a primary molded product formed by heating and pressurizing are softened by heating, and a preformed product in a softened state is obtained. To provide a method for molding a fiber-reinforced molded product that can increase the strength of a molded product by press-fitting a soft molded primary molded product into a molding space of a mold containing a molded secondary molded product Can do.

(A) is a perspective view of a preformed product, (b) is a perspective view of a primary molded product, and (c) is a perspective view of a secondary molded product. (A) is a longitudinal cross-sectional view of the molding machine, showing a state in which the mold is opened, (b) is a cross-sectional view taken along the line II-II of FIG. 2 (a). (A) is a longitudinal cross-sectional view which shows the state which closed the metal mold | die of the molding machine of Fig.2 (a), (b) is the III-III sectional view taken on the line of Fig.3 (a). It is a longitudinal cross-sectional view of the molding machine which shows the state immediately before pushing out a primary molded product with a plunger in Fig.3 (a). It is a longitudinal cross-sectional view of the molding machine which shows the state after pushing out the primary molded product in FIG. 4 with the plunger. FIG. 6 is a view taken along line VI-VI in FIG. 2. It is a perspective view which shows another form of the shape of the length direction one end part of a lower metal mold | die. It is a longitudinal cross-sectional view of the molding machine of another form.

  2 (a) and 2 (b) to FIG. 5 show a molding machine 2 for molding a fiber-reinforced molded product (a bolt which is a secondary molded product to be described later) 1 (see FIG. 1 (c)) of the present invention. Yes. The molding machine 2 includes a plurality of (upper and lower) molds 4 and 5 that form a molding space 3, a press-fit portion 6 that press-fits a softened resin into the molding space 3, and a resin that is press-fit from the press-fit portion 6. And a flow path 7 formed at the upper end of the lower mold 5 so as to guide to the molding space 3.

  At the lower end of the upper mold 4, a molding recess 4A that is recessed upward is formed. At the upper end of the lower mold 5, a molding recess 5 </ b> A that is recessed downward is formed. Each recess 4A or 5A has a semicircular cross-sectional shape and is formed with an internal thread. The upper mold 4 is attached to a movable member 8 that is lifted and lowered by a lift mechanism (not shown), and the upper mold 4 is lowered by driving the lift mechanism from the open state of FIG. It can be moved to the clamping position for clamping with the lower mold 5 shown in FIG. In the state where the upper mold 4 and the lower mold 5 shown in FIG. 3A are clamped, the recesses 4A and 5A of the molds 4 and 5 are circular as shown in FIG. 3B. become. The movable member 8 is integrated in a state where the two plates 8A and 8B are stacked in the vertical direction. The lower mold 5 is fixed to the upper end of the plate 9A located at the upper ends of the five stacked plates 9A, 9B, 9C, 9D, 9E. Although not shown, the upper mold 4, the lower mold 5, heating means for heating the pot 10 described later, the upper mold 4, the lower mold 5, described later, A cooling means for cooling the pot 10 is provided. Here, the upper mold 4, the lower mold 5, and the pot 10 described later are heated by heating means so that the temperature becomes 240 ° C.

  The press-fit portion 6 includes a cylindrical pot 10 for forming a storage portion 10A that stores a primary molded product 13 described later, and a plunger 11 that pushes out the primary molded product 13 stored in the pot 10. ing. The plunger 11 moves up and down by a drive mechanism (not shown). The pot 10 is fixed in a state of penetrating through the upper mold 4 and the two plates 8A and 8B.

  A molding method for molding the fiber reinforced molded product 1 is that a preform 12 to be placed in the molding space 3 is placed in the molding space 3 and press-fitted into the molding space 3 in which the preform 12 and the preform 12 are placed. The primary molded product 13 for heating is softened by heating, and the primary molded product 13 in the softened state is pressed into the molding space 3 in which the preformed product 12 in the softened state is arranged to be secondary. This is a method in which a molded product (fiber-reinforced molded product, specifically, a bolt) 1 is pressure-molded.

  The preform 12 is a chip, thin plate, or strip formed by impregnating a fiber material (here, carbon fiber) with a thermoplastic resin (here, phenoxy resin (thermoplastic epoxy resin, heat softening temperature 230 ° C.)). It is formed (molded) by heating and pressing a plurality (or one) of fiber reinforced plastic materials cut into a shape. The volume of the preform has a slightly smaller volume than the volume of the molding space 3. At the time of molding, molding is performed so that the directions of all the carbon fibers are in a state along the axial direction. Specifically, as shown in FIG. 1A, the preform 12 is formed (molded) into a rod-shaped member having an elliptical cross-sectional shape and long in the axial direction. The preformed product 12 is formed by, for example, a press device having the following configuration. The press device includes a mold including an upper plate and a lower plate that are vertically opposed to each other, an actuator that moves the upper plate up and down, and a heater that serves as a heating unit that heats the upper plate and the lower plate. Accordingly, a plurality (or one) of the fiber reinforced plastic materials may be arranged between the upper plate and the lower plate, and heated with a heater to be in a deformable state, and then the upper plate is lowered and the fiber is lowered. A plurality (or one) of the reinforced plastic material is pressed to form (mold) a rod-shaped member having an elliptical cross-sectional shape and a long axial direction as shown in FIG. Thereby, the fiber material (carbon fiber) can be sufficiently impregnated with the resin, the bubbles in the resin can be removed, and the strength of the preform 12 to be formed (molded) can be increased.

  The primary molded product 13 is a molded product having a volume that fills the molding space 3 in a state where the preform 12 is placed in the molding space 3. A fiber reinforced plastic cut into a chip shape, a thin plate shape or a strip shape formed by impregnating a fiber material (here, carbon fiber) with a thermoplastic resin (here, a thermoplastic epoxy resin, a heat softening temperature of 230 ° C.). It is formed by heating and pressurizing a plurality (or one) of materials. At the time of molding, the carbon fibers are formed (molded) so that the directions of all the carbon fibers are along the axial direction. Here, by using carbon fiber as the fiber material, the carbon fiber is not broken at the time of molding, and can be surely suppressed from entering the narrow gap and causing a decrease in strength. In addition to aramid fibers, polyester fibers, and polyamide fibers, various metal fibers may be used. The primary molded product 13 may be formed by the press apparatus mentioned above, and may be formed by the apparatus of a different structure. As described above, the press device includes a mold including an upper plate and a lower plate that are vertically opposed to each other, an actuator that moves the upper plate up and down, and a heater that serves as a heating unit that heats the upper plate and the lower plate. It has. Accordingly, a plurality (or one) of the fiber reinforced plastic materials may be arranged between the upper plate and the lower plate, and heated with a heater to be in a deformable state, and then the upper plate is lowered and the fiber is lowered. A plurality of reinforced plastic materials (or one) may be pressed to form (mold) a cylindrical member shown in FIG. As a result, the fiber material (carbon fiber) can be sufficiently impregnated with the resin, and bubbles in the resin can be removed, and the strength of the preform 12 to be molded can be increased.

  The secondary molded product 1 is press-fitted into the heated molding space 3 in which the preformed product 12 is arranged by the plunger 11 by being accommodated in the pot 10 and heated and softened. Pressure molding. Here, the plunger 11 is press-fitted, but any configuration may be used as long as an equivalent pressure is generated.

  Here, as a chip-like or thin-plate-like fiber reinforced plastic material for forming (molding) the preformed product 12 and the primary molded product 13, fibers (here, carbon fibers) are aligned in only one direction and impregnated with resin. For example, a resin impregnated with fibers assembled in a string shape, or a resin impregnated with a fabric in which fibers are woven vertically and horizontally can be used. Further, the carbon fiber content (fiber volume content: Vf) with respect to the phenoxy resin is set to 50%. However, the more the content exceeds 50%, the more advantageous in terms of strength. If the ratio exceeds 50%, the effect on strength is not achieved. Therefore, the carbon fiber content (fiber volume content: Vf) is 80% at the maximum, 20% at the minimum, less than 50%, preferably 30% at the minimum. You may set to the content rate of. Further, the fiber volume content of the primary molded product 13 may be set higher than the fiber volume content of the preform 12. In this way, by setting the fiber volume content of the primary molded product 13 in the portion where the screw requiring particularly high strength is set higher than the fiber volume content of the preformed product 12 in terms of cost and strength. Become advantageous. The length of the carbon fiber is preferably set to an arbitrary length not less than the diameter of the secondary molded product 1 and not more than the length of the secondary molded product 1, and specifically, for example, exceeds 5 mm. In particular, a length exceeding 10 mm is preferable in terms of strength after molding.

  As shown in FIG. 6, the flow path 7 is formed at one end in the longitudinal direction of the discharge port 7 </ b> A formed at the lower end of the pot 10 and the recess 5 </ b> A of the lower mold 5 that forms the lower side of the molding space 3. It is formed at the upper end of the lower mold 5 so as to be connected to the inlet 7B, and is formed so as to become gradually narrower toward the concave portion 5A side of the lower mold 5. The depth of the flow path 7 is the same at any position. Thus, the primary molded product 13 press-fitted by the plunger 11 is supplied into the recess 5A of the lower mold 5 via the flow path 7 that is narrower toward the recess 5A side of the lower mold 5. Accordingly, pressure can be applied to the extruded primary molded product 13, so that the fiber (carbon fiber) can be sufficiently impregnated with the resin and bubbles in the resin can be removed.

  As described above, since the female screw is formed in the concave portion 4A of the upper mold 4 and the concave portion 5A of the lower mold 5, the primary molded product 13 pushed out by the plunger 11 is the preformed product 12. The external thread 1A enters the gap between the recesses 4A and 5A of the molds 4 and 5, and the primary molded product 13 is pressed against the female screw formed on the inner surfaces of the molds 4 and 5, thereby forming the male thread 1A as the secondary molded product 1. To form the bolt 1 (see FIG. 1C).

  Further, the pressure when the primary molded product 13 is press-fitted with the plunger 11 is set to be smaller than the pressure when the molds 4 and 5 are clamped (even if the pressure is set to be the same as the pressure when clamping the mold). Good). Thus, the pressure when the primary molded product 13 is press-fitted with the plunger 11 is equal to or lower than the pressure when the molds 4 and 5 are clamped (is slightly smaller than the pressure when the molds 4 and 5 are clamped? The pressure when the primary molded product 13 is pushed out by the plunger 11 can be prevented from being opened. . Thereby, it can suppress reliably that a burr | flash generate | occur | produces in the secondary molded product 1. FIG.

  A procedure for molding the fiber-reinforced molded product (secondary molded product, bolt here) 1 of the present invention will be described. First, as described above, the preform 12 (see FIG. 1A) is formed (molded) in advance as described above, and the columnar primary molded product 13 (see FIG. 1B) is formed as described above. As described above, it is formed (molded) in advance. Next, as shown in FIG. 2 (a), the heating temperature of the upper and lower molds 4, 5 and pot 10 is set to 240 ° C. and heating is started, and then the lower mold 5 in the mold open state is opened. The preform 12 is placed in the central portion in the axial direction in the recess 5A, and the preform 12 is heated. After that, as shown in FIG. 3A, the upper mold 4 is lowered to perform mold clamping (the mold clamping force at this time is 19 MPa). Then, as shown in FIG. 4, the primary molded product 13 is accommodated in the pot 10, and the primary molded product 13 is heated. When a predetermined time (20 minutes here) has passed and the primary molded product 13 accommodated in the pot 10 is in a softened state, the molding space in which the preformed product 12 in which the plunger 11 is lowered to be softened is arranged. The primary molded product 13 is press-fitted into the interior 3 to press-mold the secondary molded product 1 (the pressure input at this time is 19 MPa). Here, the mold clamping force and the pressure input are set to the same value (19 MPa), but the mold clamping force is preferably set larger than the pressure input (for example, the mold clamping force is set to 30 MPa or more). At this time, the carbon fiber and the resin constituting the primary molded product 13 are integrally moved to the flow path 7 and are press-fitted into the molding space 3, and the preform 12 is inserted into the molding space 3 as shown in FIG. 5. , While moving to the right end, enters the gap between the outer surface of the preform 12 and the recesses 4A and 5A to form the male thread of the bolt 1 as a secondary molded product. At this time, the carbon fiber enters the gap together with the resin in a state where the orientation of the carbon fiber is along the axial direction of the preformed product 12, and the strength is not reduced. Then, when the primary molded product 13 is buried in the gap between the outer surface of the preformed product 12 and the recesses 4A and 5A, pressure below the clamping force of the molds 4 and 5 is applied to the resin, and the fiber material (here, carbon fiber) is applied. The resin can be sufficiently impregnated and air bubbles in the resin can be removed, and the strength of the secondary molded article 1 to be molded can be further increased. After the secondary molded product 1 is molded, the secondary molded product 1 is taken out by opening the molds 4 and 5 after cooling to a predetermined temperature by the cooling means. The unnecessary portion 15 formed in the flow path 7 is cut and removed. Further, the portion 16 of the primary molded product 13 integrated with the preformed product 12 may be cut and removed together with the unnecessary portion 15. The secondary molded product 1 is a hexagon socket set screw in which a hexagon socket 1B is formed as shown in FIG.

  Further, as shown in FIG. 7, when the preformed product 12 indicated by a two-dot chain line is arranged in a vertically long posture at one end portion in the length direction (axial direction) of the concave portion 4A of the lower mold 5, the preforming is performed. A locking portion 14 that locks the lower portion of one end portion in the axial direction (length direction) of the product 12 is formed continuously with the recess 4A. The locking portion 14 includes a semicircular bottom wall portion 14A that supports the bottom surface of the elliptical preform 12, and a pair of flat side wall portions 14B and 14B that extend straight upward from both widthwise ends of the bottom wall portion 14A. And. The distance between the side wall portions 14B and 14B is set to be the same as or slightly larger than the thickness of the elliptical preform 12. Therefore, by locking one end of the elliptical preform 12 in the length direction to the locking portion 14, the side wall of the preform 12 abuts on the side walls 14B and 14B of the locking portion 14, The preformed product 12 can be held in a portrait orientation. As described above, when the preform 12 having an elliptical cross section is arranged in the lower mold 5 in the vertically long posture, the lower part of one end portion of both end portions in the axial direction (length direction) of the preform 12 is formed. Although the preform 12 can be held in a vertically long posture, the locking portion 14 may not be provided. Here, the locking portion 14 is provided only at one end in the axial direction (length direction) of the preform 12, but the locking portion is provided at both ends in the axial direction (length direction) of the preform 12. Can also be implemented. Further, the upper mold 4 may be formed so as to correspond to the locking portion 14 provided in the lower mold 5. In addition, since the unnecessary part whose cross section shape | molded by the said latching | locking part 14 is elliptical remains in the edge part after shape | molding the secondary molded product 1, it cuts off the unnecessary part by cutting etc. Become.

  As the thermoplastic resin used for the fiber reinforced plastic material, a thermoplastic epoxy resin is preferably used, but may be a polycarbonate resin, a polyamide resin, a polyester resin, a polystyrene resin, a polyetherimide resin, or the like.

  In addition, the shaping | molding method of the fiber reinforced molded product which concerns on this invention is not limited to embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  In the embodiment, the cross-sectional shape of the preform 12 is an ellipse, but it may be a circle, a triangle, or a polygon including a quadrangle.

  Moreover, in the said embodiment, although the hexagon socket set screw (it is called an enamel set or a potato screw) was shown as the secondary molded product 1, recessed part 4B, 5B which forms the hexagonal head shown in FIG. Hexagonal bolts may be molded with the formed dies 4 and 5, and although not shown, square bolts, hexagonal (or square or octagonal) hole bolts, hexagonal (or square or octagonal) holes Round head bolts, hexagonal (or square or octagonal) countersunk head bolts, butterfly bolts, eye bolts, and the like may be used.

  Moreover, in the said embodiment, although the flow path 7 was the structure narrowed as the shaping | molding space 3 side, the lower side which forms the lower side of the shaping | molding space 3 from the discharge outlet 7A formed in the lower end of the pot 10 is shown. The flow path 7 may have the same width up to the inlet 7B formed at one end in the length direction of the recess 5A of the mold 5.

  Moreover, in the said embodiment, although the fiber volume content rate of the primary molded product 13 was set higher than the fiber volume content rate of the preformed product 12, the fiber volume content rate of the primary molded product 13 is set to the preformed product 12. The fiber volume content may be the same.

DESCRIPTION OF SYMBOLS 1 ... Fiber reinforced molded product (secondary molded product, bolt), 1A ... Male screw, 1B ... Hexagonal hole, 2 ... Molding machine, 3 ... Molding space, 4 ... Upper die, 4A, 4B ... Recess, 5 ... Bottom Side mold, 5A, 5B ... concave portion, 6 ... press-fitting portion, 7 ... flow path, 7A ... discharge port, 7B ... inlet, 8 ... movable member, 8A, 8B ... plate, 9A, 9B, 9C, 9D, 9E ... Plate, 10 ... Pot, 10A ... Housing, 11 ... Plunger, 12 ... Pre-formed product, 13 ... Primary molded product, 14 ... Locking part, 14A ... Bottom wall part, 14B ... Side wall part, 15 ... Unnecessary part , 16 ... part

Claims (6)

  A preform formed by heating and pressurizing a fiber reinforced plastic material formed by impregnating a fiber material with a thermoplastic resin is placed in a mold having a volume larger than the volume of the preform. A fiber-reinforced plastic material having a volume filling a gap in a molding space formed by closing the mold on which the preform is disposed, and formed by impregnating a fiber material with a thermoplastic resin The primary molded product formed by heating and pressurizing is made into a softened state by heating, and the pre-formed product arranged in the molding space is heated and softened, and becomes a softened state. The primary molded product is press-fitted into the molding space where the preformed product in a softened state is placed, and the secondary molded product is pressure-molded. Method.   The method for molding a fiber-reinforced molded article according to claim 1, wherein the primary molded article to be press-fitted is supplied into the molding space through a flow path that is narrower toward the molding space side.   An internal thread is formed on the inner surface of the mold forming the molding space, and the primary molded product to be press-fitted enters a gap between the outer surface of the preform and the inner surface of the mold, and the internal thread 3. The method for forming a fiber-reinforced molded product according to claim 1, wherein a male screw is formed as the secondary molded product by being pressed against the fiber.   The method for molding a fiber-reinforced molded product according to claim 3, wherein the fiber volume content of the primary molded product is set higher than the fiber volume content of the preformed product.   The fiber material according to any one of claims 1 to 4, wherein the fiber material constituting the preform and the fiber material constituting the primary molded product are composed of carbon fibers. Molding method for molded products.   The fiber reinforced molding according to any one of claims 1 to 5, wherein a pressure at the time of press-fitting the primary molded product is set to be equal to or lower than a pressure at the time of clamping the mold. Molding method.

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