JP7083281B2 - Resin injection molded product and its manufacturing method - Google Patents

Description

The present disclosure is a resin injection molding method in which a liquid resin is injected into a molding space (cavity) of a molding mold in which a fibrous impregnated material is set, and the impregnated material is impregnated with the liquid resin and cured, so-called RTM (Resin Transfer). The present invention relates to a resin injection molded product molded by the Molding) method and a method for manufacturing the same.

In the method for manufacturing a resin injection molded product using the RTM method, an impregnated object as a base material is set in a molding die, the molding die is closed, the molding space in which the impregnated object is placed is depressurized, and the pressure is reduced. A liquid matrix resin is injected into the formed molding space to impregnate the impregnated object with the matrix resin and then cured (see, for example, Patent Document 1).

The impregnated material used in such a manufacturing method is a laminated body in which a plurality of fiber sheets are laminated. As the fiber sheet, a strand sheet composed of a plurality of fiber bundles (strands) aligned in one direction is often used because of its ease of handling. A gap forming a recess is formed between adjacent fiber bundles in the strand sheet.

Japanese Unexamined Patent Publication No. 2017-170840

FIG. 17 shows a partial cross-sectional view of the resin injection molded product 201. FIG. 18 shows an enlarged cross-sectional view of a portion of the resin injection molded product 201 of FIG. 17 surrounded by XVIII. In the resin injection molded product 201 molded by the RTM method as described above, as shown in FIGS. 17 and 18, the matrix resin 203 covers the surface of the impregnated material 205 to form the resin surface layer 207.

In such a resin injection molded product 201, the matrix resin 203 is accumulated in the recess 213 between the adjacent fiber bundles 211 in the fiber sheet 209 forming the impregnated material 205, so that the matrix resin is formed at the boundary between the fiber bundles 211 of the fiber sheet 209. 203 forms a resin-rich portion 215 that is thicker than other parts on the surface of the fiber sheet 209. When the resin-rich portion 215 is formed on the surface side of the resin-injected molded product 201, streaky sink marks 217 are generated in the portion of the resin surface layer 207 corresponding to the resin-rich portion 215 due to shrinkage after molding.

Such sink marks 217 impair the appearance of the resin injection molded product 201, and the resin injection molded product 201 with sink marks 217 does not look good. The surface of the resin injection molded product 201 may be painted, but it is difficult to hide the sink marks 217 only by painting. Therefore, it is conceivable to eliminate the sink marks 217 generated in the resin injection molded product 201 by polishing the resin surface layer 207, but since the polishing work of the resin surface layer 207 takes a considerable amount of time, the productivity is lowered by that amount. Will lead to an increase in cost.

The technique of the present disclosure has been made in view of such a point, and an object thereof is to suppress the occurrence of sink marks on the surface of the resin injection molded product and to provide a good-looking resin injection molded product. There is something in it.

In order to achieve the above object, in the technique of the present disclosure, a nonwoven fabric is provided adjacent to the fiber sheet located on the surface side of the impregnated object, and the fibers of the nonwoven fabric are allowed to enter the recesses in the fiber sheet. ..

Specifically, the technique of the present disclosure is intended for a resin injection molded product including an impregnated laminate in which a plurality of fiber sheets are laminated and a matrix resin cured in a state of being impregnated in the impregnated laminate. And. The matrix resin covers the surface of the impregnated laminate to form a resin surface layer. A recess is formed on at least one surface of a predetermined fiber sheet located on the resin surface layer side of the impregnated laminate. In the resin injection molded product according to the technique of the present disclosure, the impregnated laminate is provided with a nonwoven fabric at a position adjacent to the surface on which the recess is formed in the predetermined fiber sheet.

According to this configuration, since the nonwoven fabric is provided adjacent to the fiber sheet located on the surface side of the impregnated laminate, the fibers of the nonwoven fabric enter the recesses in the fiber sheet when molding the resin injection molded product. , Only the matrix resin can be prevented from accumulating in the recess. As a result, the resin content of the resin-rich portion formed in the recess is reduced, so that the amount of shrinkage of the resin-rich portion after molding is reduced. Moreover, since the non-woven fabric follows the shrinkage of the resin-rich portion, the influence of the shrinkage of the resin-rich portion on the surface of the resin-injected molded product is alleviated, and it is possible to suppress the occurrence of sink marks on the surface of the resin-injected molded product. can.

In such a resin injection molded product, the impregnated laminate is composed of a plurality of fiber bundles aligned in one direction as a predetermined fiber sheet, and the gap between adjacent fiber bundles forms a recess. May have. In this case, the nonwoven fabric is preferably arranged adjacent to the surface of the strand sheet on the resin surface layer side.

Sink marks on the surface of the resin injection molded product are likely to occur due to the formation of resin-rich portions in the recesses between the fiber bundles of the strand sheet as described above. On the other hand, according to the above configuration, since the nonwoven fabric is arranged adjacent to the surface of the strand sheet on the resin surface layer side, it is possible to effectively suppress the occurrence of sink marks on the surface of the resin injection molded product. can.

Further, the impregnated laminate may have a biaxially woven cross sheet as a fiber sheet. This cross sheet constitutes the surface of the impregnated laminate and may be covered with a resin surface layer. In this case, the matrix resin forming the resin surface layer may be a translucent resin.

According to this configuration, a cross sheet is provided directly under the resin surface layer so that the resin surface layer is formed of a translucent resin, so that the cross sheet can be visually recognized through the resin surface layer in the appearance of the resin injection molded product, and the resin The design of the injection molded product can be enhanced.

The nonwoven fabric is preferably arranged between the strand sheet and the cross sheet.

According to this configuration, since the non-woven fabric is provided adjacent to the strand sheet close to the resin surface layer next to the cloth sheet, the shrinkage amount of the resin rich portion after molding is reduced at the position close to the resin surface layer, and the resin rich portion is formed. The influence of the shrinkage on the surface of the resin-injected molded product is alleviated, and the occurrence of sink marks on the surface of the resin-injected molded product can be effectively suppressed.

The cross sheet is a predetermined fiber sheet and forms a recess in the gap of the texture. The non-woven fabric may be arranged adjacent to the surface of the cloth sheet on the resin surface layer side.

In the molding of the resin injection molded product, the matrix resin is accumulated in the recesses formed by the creases in the cross sheet, so that a resin-rich portion in which the matrix resin is thicker than other parts on the surface of the cross sheet is formed. On the other hand, according to the above configuration, it is possible to suppress the occurrence of sink marks on the surface of the resin injection molded product due to the shrinkage of the resin-rich portion formed in the recess of the cross sheet.

The non-woven fabric is preferably made of carbon fiber.

Despite being lightweight, carbon fiber has excellent mechanical properties. According to the above configuration, since the nonwoven fabric made of carbon fiber is adopted as the nonwoven fabric provided in the impregnated laminate, it is advantageous to enhance the mechanical properties of the resin injection molded product.

Further, it is preferable that an acid anhydride-based curing agent is used for the matrix resin.

The acid anhydride-based curing agent has a long pot life (pot life), has a good balance of physical properties such as mechanical properties, chemical properties, and electrical properties, and the curing reaction proceeds relatively slowly. It has the property of. According to the above configuration, since an acid anhydride-based curing agent is used as the curing agent added to the matrix resin, the molding time of the resin injection molded product becomes long, but the shrinkage of the resin-rich portion after molding becomes long. The amount is reduced, which is advantageous in suppressing the occurrence of sink marks on the surface of the resin injection molded product.

The technique of the present disclosure also covers the method for manufacturing a resin injection molded product as described above. In the method for manufacturing a resin injection molded product according to the technique of the present disclosure, a plurality of fiber sheets are laminated, and a predetermined fiber sheet having a recess formed on at least one surface thereof is arranged on the surface side. A preparatory step for preparing the impregnated laminate, a set step in which the impregnated laminate is set in a molding die and the impregnated laminate is placed in a molding space formed by the molding die, and in the molding space. After depressurizing, a liquid matrix resin is injected into the molding space to impregnate the impregnated laminate, and the matrix resin impregnated in the impregnated laminate is cured and the surface of the impregnated laminate is cured by the matrix resin. Includes a curing step to form a resin surface layer that covers.

Here, "setting the impregnated laminate in the molding die" means preparing an impregnated laminate formed by laminating a plurality of fiber sheets in advance and arranging the impregnated laminate in the molding die. Of course, this also includes the case where a plurality of fiber sheets are laminated and arranged in order in a molding die and the impregnated laminate is set in the molding die. Further, the method for manufacturing a resin injection molded product, which is the subject of the technique of the present disclosure, is a vacuum auxiliary resin injection molding method in which a liquid resin is impregnated into an impregnated laminate by utilizing a pressure difference, so-called VaRTM (Vacuum-assisted Resin). It also includes a manufacturing method using the Transfer Molding) method. Then, in the preparation method of the resin injection molded product according to the technique of the present disclosure, in the preparation step, an impregnated laminate in which the nonwoven fabric is provided at the position adjacent to the surface where the recess is formed in the predetermined fiber sheet is prepared.

According to this configuration, in the impregnated laminate prepared in the preparation step, the non-woven fabric is provided at the position adjacent to the fiber sheet located on the surface side, so that when the molding space is depressurized in the impregnation step, the weight is reduced. It is possible to prevent the fibers of the non-woven fabric from entering the recesses in the fiber sheet and preventing only the matrix resin from accumulating in the recesses. As a result, the resin content of the resin-rich portion formed in the recess is reduced, so that the amount of shrinkage of the resin-rich portion after the curing step is reduced. Moreover, since the non-woven fabric follows the shrinkage of the resin-rich portion, the influence of the shrinkage of the resin-rich portion on the surface of the resin-injected molded product is alleviated, and it is possible to suppress the occurrence of sink marks on the surface of the resin-injected molded product. can.

According to the resin injection molded product and the manufacturing method thereof according to the technique of the present disclosure, it is possible to suppress the occurrence of sink marks on the surface of the resin injection molded product and realize a resin injection molded product having a good appearance.

FIG. 1 is a schematic view showing the configuration of a resin injection molded product according to an embodiment. FIG. 2 is a partial cross-sectional view of the resin injection molded product according to the embodiment. FIG. 3 is a partial cross-sectional perspective view of a strand sheet used in the resin injection molded product according to the embodiment. FIG. 4 is a schematic plan view of a cross sheet used in the resin injection molded product according to the embodiment. FIG. 5 is an enlarged view of a portion surrounded by V in the resin injection molded product of FIG. 2. FIG. 6 is a schematic configuration diagram showing a molding apparatus and an impregnated laminate of the resin injection molded product according to the embodiment. FIG. 7 is a diagram showing a state of a set step in a method for manufacturing a resin injection molded product according to an embodiment. FIG. 8 is an enlarged view of a portion surrounded by VIII in the impregnated laminate of FIG. 7. FIG. 9 is a diagram showing how the molding space is depressurized in the impregnation step in the method for manufacturing a resin injection molded product according to the embodiment. FIG. 10 is an enlarged view of a portion surrounded by X in the impregnated laminate of FIG. FIG. 11 is a diagram showing a state in which a matrix resin is injected into a molding space in an impregnation step in the method for manufacturing a resin injection molded product according to an embodiment. FIG. 12 is an enlarged view of a portion of the impregnated laminate of FIG. 11 surrounded by XII. FIG. 13 is a diagram showing the evaluation of the smoothness of the resin injection molded products according to Examples 1 to 5 and Comparative Examples. FIG. 14 is a diagram showing an evaluation of the elastic modulus of the resin injection molded product according to Examples 1 to 5 and Comparative Example. FIG. 15 is a view corresponding to FIG. 2 of the resin injection molded product according to the modified example 1. FIG. 16 is a view corresponding to FIG. 2 of the resin injection molded product according to the modified example 2. FIG. 17 is a partial cross-sectional view of a resin injection molded product. FIG. 18 is an enlarged view of a portion surrounded by XVIII in the resin injection molded product of FIG.

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

FIG. 1 shows a schematic view of the configuration of the resin injection molded product 1 according to this embodiment. FIG. 2 shows a partial cross-sectional view of the resin injection molded product 1. FIG. 3 shows a partial cross-sectional perspective view of the strand sheet 17 used in the resin injection molded product 1. FIG. 4 shows a schematic plan view of the cross sheet 13 used for the resin injection molded product 1. FIG. 5 shows an enlarged view of a portion surrounded by V in the resin injection molded product 1 of FIG.

The resin injection molded product 1 is used for a body panel (body outer panel) constituting an automobile door (side door or back door), a hood, a roof, a fender, or the like. As shown in FIGS. 1 and 2, the resin injection molded product 1 is a fiber-reinforced resin composite, and is an impregnated laminate 5 containing the reinforcing fibers 3 and 21, and a matrix impregnated in the impregnated laminate 5. It is composed of resin 7. The impregnated laminate 5 is a fibrous base material in which a plurality of fiber sheets 9 are laminated, and is included in the matrix resin 7. The impregnated laminate 5 includes a base material main body 11, a cloth sheet 13, and a non-woven fabric 15.

The base material main body 11 is formed by combining a plurality of strand sheets 17 which are fiber sheets 9. As shown in FIG. 3, the strand sheet 17 is a unidirectional (UD: Uni-Direction) material in which a large number of reinforcing fibers 3 are aligned in one direction. The reinforcing fibers 3 forming the strand sheet 17 are bundled by the auxiliary thread 4 to form a plurality of fiber bundles (strands) 18 arranged in one direction in the sheet surface direction. Examples of the strand sheet 17 include a fiber knitted fabric called NCF (Non-Crimp Fabric).

Examples of the reinforcing fiber 3 of the strand sheet 17 include inorganic fibers such as carbon fibers, glass fibers and ceramics fibers, metal fibers such as stainless steel fibers and steel fibers, and organic fibers such as polyamide fibers, aramid fibers and polyethylene fibers. .. Among them, carbon fiber has excellent mechanical properties in spite of its light weight. In the strand sheet 17, one type of reinforcing fiber 3 may be used alone, or two or more types may be used in combination. As the auxiliary thread 4, a stitch thread made of a synthetic resin thread such as a polyamide resin or a polyester resin, a glass fiber thread, or the like is used.

The strand sheet 17 forming the base material main body 11 of this embodiment has the first strand sheet 17a and the second strand sheet 17b arranged in order from the back surface side to the front surface side (design surface side) of the resin injection molded product 1. There are four sheets, a third strand sheet 17c and a fourth strand sheet 17d. The first to fourth strand sheets 17a, 17b, 17c, and 17d each have a predetermined fiber orientation with respect to a reference direction, and are laminated by a pseudo-isotropic laminating method. In the pseudo-isotropic laminating method, the fiber orientations of the first to fourth strand sheets 17a, 17b, 17c, and 17d are assigned to any of 0 °, 45 °, 90 °, and −45 ° to set a predetermined crossing angle with each other. have.

Specifically, the fiber orientation of the first strand sheet 17a is −45 °, the fiber orientation of the second strand sheet 17b is 45 °, the fiber orientation of the third strand sheet 17c is 90 °, and the fourth. The fiber orientation of the strand sheet 17d is 0 °. With such a laminated layout, the resin injection molded product 1 is imparted with pseudo-isotropic properties while realizing mechanical properties having excellent strength (elastic modulus, etc.). On both the front and back surfaces of the first to fourth strand sheets 17a, 17b, 17c, 17d, a plurality of recesses 19 formed by gaps between the joints of the adjacent fiber bundles 18 are linearly formed along the fiber bundles 18. ..

The cross sheet 13 is a fiber sheet 9 constituting the surface of the impregnated laminate 5. As shown in FIG. 4, the cross sheet 13 is a fiber woven fabric in which a fiber bundle 23 in which a plurality of reinforcing fibers 21 are bundled is woven into a plain weave on two axes as a warp 25 and a weft 27, and is a checkerboard by light reflection. It has a weave pattern like a pattern. Recesses 29 formed by gaps in the texture are formed on both the front and back surfaces of the cross sheet 13. Examples of the reinforcing fiber 21 forming the cross sheet 13 include the above-mentioned reinforcing fiber 3 used for the strand sheet 17, and carbon fiber is preferable for the same reason as the strand sheet 17.

The non-woven fabric 15 is provided on the base material main body 11, and is between the fourth strand sheet 17d and the cross sheet 13 on the surface of the base material main body 11, that is, the surface side (with the third strand sheet 17c) of the fourth strand sheet 17d. Is located adjacent to (on the opposite side). Examples of the fiber forming the nonwoven fabric 15 include the above-mentioned reinforcing fiber 3 used for the strand sheet 17, and carbon fiber is preferable for the same reason as the strand sheet 17. Carbon fibers include PAN-based carbon fibers made of Polyacrylonitrile (PAN) fibers and pitch-based carbon fibers made of pitch fibers, but they have a good balance of performance such as strength, cost, and ease of use. The former is preferable because of its goodness.

The matrix resin 7 is cured in a state of being evenly impregnated on the surface of the impregnated laminate 5, and as shown in FIG. 5, the impregnated laminate 5 is solidified and the outer surface thereof is covered to form the resin surface layer 31. is doing. That is, the outer shell of the resin injection molded product 1 is made of the matrix resin 7. The matrix resin 7 is filled in the recesses 19 of the first to fourth strand sheets 17a, 17b, 17c, and 17d as well as in the recesses 29 of the cross sheet 13, and is compared with other places. A relatively thick resin-rich portion 33 (a portion surrounded by a two-dot chain line in FIG. 5) is formed. A thermosetting resin is used as the matrix resin 7.

Examples of the thermosetting resin include urethane resin, silicone, vinyl ester resin, and cyanic acid ester resin. Among them, epoxy resin and vinyl ester resin have excellent heat resistance, shock absorption and chemical resistance. The thermosetting resin may contain additives such as a curing agent, a curing accelerator, and a flame retardant. The thermosetting resin may be used alone or in combination of two or more. A thermosetting resin having translucency, for example, an epoxy resin, is used for the matrix resin 7 of this embodiment, and the texture pattern of the cross sheet 13 can be visually recognized through the resin surface layer 31 on the appearance of the resin injection molded product 1. Will be done.

The fiber sheet 9 on the surface side of the impregnated laminate 5, specifically, the resin-rich portion 33 formed in the recesses 19 and 29 in the fourth strand sheet 17d and the cross sheet 13 on the surface of the base material main body 11 is made of resin. This is an important factor that causes sink marks on the surface of the injection molded product 1, that is, the resin surface layer 31. In the resin injection molded product 1 of this embodiment, the fibers of the nonwoven fabric 15 are contained in the recesses 19 and 29 on the front surface side of the fourth strand sheet 17d and the back surface side of the cross sheet 13, and the recesses 19, 29 are contained. The resin content in the resin-rich portion 33 inside is reduced. Further, the nonwoven fabric 15 regulates that the fiber bundle 23 of the cross sheet 13 is twisted or disturbed by the flow at the time of injecting the matrix resin 7 in the production of the resin injection molded product 1, and the resin-rich portion 33 is used. It plays a role of alleviating the influence on the surface of the resin injection molded product 1 due to shrinkage after molding.

The resin injection molded product 1 having the above configuration is manufactured by using the RTM method. FIG. 6 shows a schematic configuration diagram of a molding apparatus 101 and an impregnated laminate 5 used for molding the resin injection molded product 1. As shown in FIG. 6, the molding device 101 of the resin injection molded product 1 includes a molding die 103, a resin injection device 105, a vacuum suction device 107, and a heating device (not shown), and is molded by the heating device. The temperature of 103 can be adjusted.

The molding die 103 is composed of a cavity die 109 and a core die 111 arranged so as to face each other. The cabinet type 109 is a fixed type and has a concave portion 113. The inner surface of the concave portion 113 is a molding surface 115 for molding the outer surface of the resin injection molded product 1, which is shown in a flat shape in FIG. 6, but has a shape corresponding to the body panel formed by the resin injection molded product 1. .. The core type 111 is a movable type and has a convex portion (core) 117 that fits into the concave portion 113.

The cavity type 109 and the core type 111 are molded together to form a molding space (cavity) 119 between the concave portion 113 and the convex portion 117. The core type 111 is provided with a resin injection port 121 and a vacuum suction port 123. For example, the opening of the resin injection port 121 is positioned in the central portion of the molding space 119, and the opening of the vacuum suction port 123 is positioned on the outer peripheral side of the molding space 119.

The resin injection device 105 is connected to the resin injection port 121 of the core type 111 via the resin injection path 125. Then, the resin injection device 105 injects the liquid matrix resin 7 into the molding space 119 from the resin injection port 121 through the resin injection path 125. An on-off valve 127 is provided in the middle of the resin injection path 125.

The vacuum suction device 107 is connected to the vacuum suction port 123 of the core type 111 via the vacuum suction path 129. Then, the vacuum suction device 107 is adapted to depressurize the molding space 119 from the vacuum suction port 123 through the vacuum suction path 129. An on-off valve 131 is provided in the middle of the vacuum suction path 129.

A method for manufacturing a resin injection molded product 1 using such a molding apparatus 101 includes a preparation step, a set step, an impregnation step, and a curing step. The manufacturing method of the resin injection molded product 1 will be described below with reference to FIGS. 7 to 12.

FIG. 7 is a diagram showing a state of a set step in the manufacturing method of the resin injection molded product 1. FIG. 8 is an enlarged view of a portion of the impregnated laminate 5 of FIG. 7 surrounded by VIII. FIG. 9 is a diagram showing how the molding space 119 is depressurized in the impregnation step in the manufacturing method of the resin injection molded product 1. FIG. 10 is an enlarged view of a portion surrounded by X in the impregnated laminate 5 of FIG. FIG. 11 is a diagram showing a state in which the matrix resin 7 is injected into the molding space 119 in the impregnation step in the manufacturing method of the resin injection molded product 1. FIG. 12 is an enlarged view of a portion of the impregnated laminate 5 of FIG. 11 surrounded by XII.

In the preparation step, as a preform in which the impregnated laminate 5 in which the first to fourth strand sheets 17a, 17b, 17c, 17d (base material main body 11), the nonwoven fabric 15 and the cloth sheet 13 are laminated in advance is preformed. prepare. In the impregnated laminate 5, the nonwoven fabric 15 is provided between the fourth strand sheet 17d and the cross sheet 13, that is, at a position adjacent to the surface of the fourth strand sheet 17d on the resin surface layer 31 side. The first to fourth strand sheets 17a, 17b, 17c, 17d, the nonwoven fabric 15 and the cloth sheet 13 constituting the impregnated laminate 5 have adhesiveness (familiarity) between the liquid matrix resin 7 and the reinforcing fibers 3, 21. ) Is applied to improve the sizing agent. As the sizing agent, for example, a mixture of bisphenol A epoxy and unsaturated polyester or bisphenol A ester is used.

Next, in the setting step, the prepared impregnated laminate 5 is set in the concave portion 113 of the cabinet type 109. Then, as shown in FIG. 7, the cavity type 109 in which the impregnated laminated body 5 is set and the core type 111 are closed to form a molding space 119 between the concave portion 113 and the convex portion 117. The impregnated laminate 5 is placed in the molding space 119. In the impregnated laminate 5 at this time, as shown in FIG. 8, the fibers of the nonwoven fabric 115 do not have to have yet entered the recesses 19 of the fourth strand sheet 17d and the recesses 29 of the cross sheet 13.

Subsequently, in the impregnation step, as shown in FIG. 9, the vacuum suction device 107 is operated with the on-off valve 127 of the vacuum suction device 107 open, so that the molding space 119 is depressurized by vacuum suction through the vacuum suction port 123. .. At this time, in the impregnated laminate 5, as shown in FIG. 10, the fibers of the nonwoven fabric 15 enter the recess 19 on the front surface of the fourth strand sheet 17d and the recess 29 on the back surface of the cross sheet 13 due to the depressurizing action. After such depressurization, the on-off valve 127 of the vacuum suction device 107 is closed. Then, as shown in FIG. 11, by operating the resin injection device 105 with the on-off valve 131 of the resin injection device 105 in the open state, the liquid matrix resin 7 is injected into the molding space 119 through the resin injection port 121 to form a corner. Distribute to everyone. In this way, as shown in FIG. 12, the matrix resin 7 is impregnated over the entire impregnated laminate 5.

An amine-based curing agent or an acid anhydride-based curing agent is added to the matrix resin 7 injected at this time. Examples of the amine-based curing agent include triethylenetetramine compounds. Examples of the acid anhydride-based curing agent include methylhexahydrophthalic anhydride.

Further, in the curing step, the heating device is operated to heat the temperature of the molding die 103 to a predetermined temperature at which the matrix resin 7 is cured, thereby curing the matrix resin 7 impregnated in the impregnated laminate 5. After that, the molding die 103 is opened, the resin injection molded product 105 in which the matrix resin 7 is cooled is taken out, and terminal treatment is performed to remove unnecessary pieces such as gate residue attached to the resin injection molded product 105. In this way, the resin injection molded product 1 can be manufactured.

According to the resin injection molded product 1 and the manufacturing method thereof according to this embodiment, the nonwoven fabric 15 is provided between the fourth strand sheet 17d and the cross sheet 13 located on the surface side of the impregnated laminate 5. The fibers of the nonwoven fabric 15 can enter the recesses 19 and 29 on the front surface side of the fourth strand sheet 17d and the back surface side of the cross sheet 13, so that only the matrix resin 7 does not accumulate in the recesses 19 and 29. .. As a result, the resin content of the resin-rich portions 33 formed in the recesses 19 and 29 decreases, so that the amount of shrinkage of the resin-rich portions 33 after molding decreases. Moreover, since the nonwoven fabric 15 follows the shrinkage of the resin-rich portion 33, the influence of the shrinkage of the resin-rich portion 33 on the surface of the resin-injected molded product 1 is alleviated, and sink marks occur on the surface of the resin-injected molded product 1. Can be suppressed. As a result, it is possible to realize a resin injection molded product 1 having a good appearance.

-Appearance and performance evaluation of resin injection molded products-
The resin injection-molded products 1 according to Examples 1 to 5 and the resin injection-molded products according to Comparative Examples shown below were manufactured by using the RTM method, and their appearance properties and mechanical properties were evaluated, respectively. In the following, for convenience, the configuration of the resin injection molded product 1 according to the comparative example will also be described with reference numerals similar to those in the above embodiment.

[Example 1]
The resin injection molded product 1 according to the first embodiment was manufactured by using the impregnated laminate 5 composed of the first to fourth strand sheets 17a, 17b, 17c, 17d and the cross sheet 13 as in the above embodiment. NCF made of carbon fiber was used for the first to fourth strand sheets 17a, 17b, 17c, and 17d, respectively. For the cross sheet 13, a plain weave fiber woven fabric made of carbon fiber was used. As the nonwoven fabric 15, an inorganic fiber sheet-like material made of PAN-based carbon fiber was used. In the nonwoven fabric 15, the fiber diameter of the carbon fiber is about 7 μm, and the basis weight is about 10 g / m ² . As the sizing agent, a mixture of bisphenol A epoxy and unsaturated polyester was used. As the matrix resin 7, an epoxy resin was used. As the curing agent, a triethylenetetramine compound, which is an amine-based curing agent, was used.

[Example 2]
As the resin injection molded product 1 according to Example 2, an inorganic fiber sheet-like material made of pitch-based carbon fibers was used as the nonwoven fabric 15 of the impregnated laminate 5. In the nonwoven fabric 15, the fiber diameter of the carbon fiber is about 11 μm, and the basis weight is about 40 g / m ² . Other configurations of the resin injection molded product 1 according to the second embodiment are the same as those of the resin injection molded product 1 according to the first embodiment.

[Example 3]
As the resin injection molded product 1 according to Example 3, an organic fiber sheet-like material made of polyamide fiber was used as the nonwoven fabric 15 of the impregnated laminate 5. In the nonwoven fabric 15, the fiber diameter of the polyamide fiber is about 4 μm, and the basis weight is about 45 g / m ² . Other configurations of the resin injection molded product 1 according to the third embodiment are the same as those of the resin injection molded product 1 according to the first embodiment.

[Example 4]
As the resin injection molded product 1 according to Example 4, an organic fiber sheet-like material made of aramid fiber was used as the nonwoven fabric 15 of the impregnated laminate 5. In the nonwoven fabric 15, the fiber diameter of the aramid fiber is about 12 μm, and the basis weight is about 20 g / m ² . Other configurations of the resin injection molded product 1 according to the fourth embodiment are the same as those of the resin injection molded product 1 according to the first embodiment.

[Example 5]
In the resin injection molded product 1 according to Example 5, an inorganic fiber sheet-like material made of PAN-based carbon fiber was used as the nonwoven fabric 15 of the impregnated laminate 5. The fiber diameter of the carbon fiber of the nonwoven fabric 15 is about 7 μm, and the basis weight is about 10 g / m ² . As the curing agent for the matrix resin 7, methylhexahydrophthalic anhydride, which is an acid anhydride-based curing agent, was used. Other configurations of the resin injection molded product 1 according to the fifth embodiment are the same as those of the resin injection molded product 1 according to the first embodiment.

[Comparison example]
The resin injection molded product according to the comparative example does not include the nonwoven fabric 15 in the impregnated laminate 5. Other configurations of the resin injection molded product according to this comparative example are the same as those of the resin injection molded product 1 according to the first embodiment.

For the resin injection molded products 1 according to Examples 1 to 5 and Comparative Examples, the surface smoothness over a long wavelength was measured using a wave scan measuring device (manufactured by BYK Adaptives & Instruments). FIG. 13 shows the evaluation of the smoothness of the resin injection molded product 1 according to Examples 1 to 5 and Comparative Example. The scan value indicating the surface smoothness indicates that the lower the scan value, the better the appearance.

As shown in FIG. 13, the scan value indicating the surface smoothness of the resin injection molded product according to the comparative example exceeds 65. On the other hand, the scan value of the resin injection molded product 1 according to Examples 1 to 5 was less than 60. In particular, the scan value of the resin injection molded product 1 according to Example 5 was less than 20, which was slightly higher than 10. From the measurement results of such surface smoothness, the smoothness of the resin injection molded product 1 according to Examples 1 to 5, and particularly the resin injection molded product 1 according to Example 5, is higher than the smoothness of the resin injection molded product according to the comparative example. Was also confirmed to be enhanced.

In addition, the elastic modulus was measured for the resin injection molded products according to Examples 1 to 5 and Comparative Example. The elastic modulus was measured by measuring the dynamic viscoelasticity of the resin injection molded product at 30 ° C. using a dynamic viscoelasticity measuring device (Rheogel-E4000 manufactured by UBM). FIG. 14 shows the evaluation of the elastic modulus of the resin injection molded product according to Examples 1 to 5 and Comparative Example.

As shown in FIG. 14, the elastic modulus of the resin injection molded product according to the comparative example was 25 GPa or more. On the other hand, the elastic modulus of the resin injection molded product 1 according to Examples 1 and 5 was also 25 GPa or more. The elastic modulus of the resin injection molded product 1 according to Examples 2 to 4 was lower than 25 GPa, but was around 20 PGa. From the measurement results of the elastic modulus, even the resin injection molded product 1 according to Examples 1 to 5 having the non-woven fabric 15 on the surface side causes a significant decrease in the elastic modulus as compared with the resin injection molded product according to the comparative example. In particular, it was confirmed that the resin-injected molded product 1 according to Examples 1 and 5 in which the PAN-based carbon fiber was used for the non-woven fabric 15 exhibited the same elastic modulus as the resin-injected molded product according to the comparative example.

As described above, among Examples 1 to 5, the resin injection molded product according to Example 1 in which PAN-based carbon fiber is used for the nonwoven fabric 15 and an acid anhydride-based curing agent is used as the curing agent for the matrix resin 7. No. 1 has good mechanical properties (elastic modulus) and high surface smoothness. Therefore, in the resin injection molded product 1, it is possible to provide the non-woven fabric 15 made of PAN-based carbon fibers and use an acid anhydride-based curing agent for the matrix resin 7, while maintaining the mechanical properties (elastic modulus) and surface smoothness. It is effective in increasing.

As described above, a preferred embodiment of the technique of the present disclosure has been described. However, the technique of the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. are made as appropriate. In addition, the components described in the attached drawings and the detailed description may include components that are not essential for solving the problem. Therefore, it should not be immediately determined that those non-essential components are essential by the fact that those non-essential components are described in the accompanying drawings or detailed description.

For example, the above embodiment may have the following configuration.

FIG. 15 shows a diagram corresponding to FIG. 2 of the resin injection molded product 1 according to the modified example 1. In the above embodiment, the resin injection molded product 1 in which the nonwoven fabric 15 is arranged only between the fourth strand sheet 17d forming the surface of the base material main body 11 and the cross sheet 13 has been described as an example, but the present invention is limited to this. do not have. As shown in FIG. 15, in addition to being arranged between the fourth strand sheet 17d and the cloth sheet 13, the nonwoven fabric 15 may be arranged adjacent to the surface of the cloth sheet 13 on the resin surface layer 31 side. .. According to such a configuration, the shrinkage of the resin rich portion 33 formed in the recess 19 on the front surface side of the fourth strand sheet 17d and the recess 29 on the back surface side of the cross sheet 13, and the recess 29 on the front surface side of the cross sheet 13. It is possible to suppress the occurrence of sink marks on the surface of the resin injection molded product 1 due to the shrinkage of the resin-rich portion 33 formed in.

FIG. 16 shows a diagram corresponding to FIG. 2 of the resin injection molded product 1 according to the modified example 2. As shown in FIG. 16, the nonwoven fabric 15 is not arranged between the fourth strand sheet 17d and the cross sheet 13, and may be arranged adjacent to the surface of the cross sheet 13 on the resin surface layer 31 side only. According to such a configuration, it is possible to suppress the occurrence of sink marks on the surface of the resin injection molded product 1 due to the shrinkage of the resin rich portion 33 formed in the recess 29 on the surface side of the cross sheet 13.

Further, in the above embodiment, the liquid matrix resin 7 is injected into the molding space 119 of the molding die 103 in which the impregnated laminate 5 is set, and the impregnated laminate is impregnated with the matrix resin 7 by the resin injection using the RTM method. Although the method for manufacturing the molded product 1 has been described as an example, the present invention is not limited to this. In the technique of the present disclosure, the impregnated laminate 5 is set in a molding die, the impregnated laminate 5 set in the molding die is covered with a film-shaped bag material and sealed, and then between the molding die and the bag material. The formed molding space is depressurized through a vacuum suction port provided on one side thereof, and a liquid matrix resin 7 is injected into the molding space from a resin injection port provided on the other side to impregnate the laminated layer. It can also be applied to a method for producing a resin injection molded product 1 using the VaRTM method, such as impregnating the body 5 with the matrix resin 7.

Further, in the above embodiment, the impregnated laminate 5 is composed of four strand sheets 17 (first to fourth strand sheets 17a, 17b, 17c, 17d) and a cross sheet 13, but the present invention is not limited to this. The base material main body 11 forming the impregnated laminate 5 may be composed of five or more strand sheets 17, or may be composed of three or less strand sheets 17. Further, the impregnated laminate 5 does not have to include the cross sheet 13.

Further, in the above embodiment, the fiber sheet 9 constituting the base material main body 11 of the impregnated laminate 5 is the first to fourth strand sheets 17a, 17b, 17c, 17d made of NCF or the like. Not exclusively. The fiber sheet 9 used for the base material main body 11 of the impregnated laminate 5 may be a sheet-like fiber made of a large number of reinforcing fibers 3, a fiber sheet made of a UD material other than a strand sheet, other woven fabrics, knitted fabrics, or the like. It may be. The fiber sheets 9 and 13 constituting the impregnated laminate 5 may be impregnated with a liquid resin and may have a recess formed by a gap or the like on at least one surface thereof.

Further, in the above embodiment, the thermosetting resin is used as the matrix resin 7, but the present invention is not limited to this. As the matrix resin 7, a thermoplastic resin such as an olefin resin, a polyester resin, a thermoplastic epoxy resin, an amide resin, a thermoplastic polyurethane resin, a sulfide resin, or an acrylic resin may be used. The thermoplastic resin may be used alone or in combination of two or more.

Further, in the above embodiment, the resin injection molded product 1 is used for the body panel of an automobile, but the present invention is not limited to this. The body panel of an automobile is only an example of the use of the resin injection molded product 1, and the resin injection molded product 1 may be used for other automobile parts such as seats, suspensions, and floors, and is limited to automobile applications. However, it can be widely used for other purposes such as aircraft parts, bicycle parts, ship parts, windmill blades, sports equipment, and building structural materials.

As described above, the technique of the present disclosure is useful for a resin injection molded product molded by the RTM method and a method for producing the same.

1 Resin injection molded product 3 Reinforcing fiber 4 Auxiliary thread 5 Impregnated laminate 7 Matrix resin 9 Fiber sheet 11 Base material body 13 Cross sheet (fiber sheet)
15 Non-woven fabric 17 Strand sheet 17a First strand sheet (fiber sheet)
17b 2nd strand sheet (fiber sheet)
17c 3rd strand sheet (fiber sheet)
17d 4th strand sheet (fiber sheet)
18 Fiber bundle 19 Reinforcement fiber 23 Fiber bundle 25 Warp 27 Weft 29 Recess 31 Resin surface layer 33 Resin rich part 101 Molding device 103 Molding type 105 Resin injection device 107 Vacuum suction device 109 Cavi type 111 Core type 113 Concave part 115 Molding surface 117 Convex part 119 Molding space 121 Resin injection port 123 Vacuum suction port 125 Resin injection path 127 On-off valve 129 Vacuum suction path 131 On-off valve

Claims (10)

An impregnated laminate (5) in which a plurality of fiber sheets (9) are laminated, and
The matrix resin (7) cured in a state of being impregnated in the impregnated laminate (5) is provided.
The matrix resin (7) covers the surface of the impregnated laminate (5) to form a resin surface layer (31), and is located on the resin surface layer (31) side of the impregnated laminate (5). A resin injection molded product having a recess (19, 29) formed on at least one surface of the fiber sheet (9).
In the impregnated laminate (5), a nonwoven fabric (15) is provided at a position adjacent to a surface on which the recesses (19, 29) are formed in the predetermined fiber sheet (9).
The fibers of the non-woven fabric (15) enter the recesses (19, 29) and enter.
Only the resin-rich portion (33) made of the fibers of the nonwoven fabric (15) and the matrix resin (7) is provided in the recesses (19, 29).
A resin injection molded product characterized by this. An impregnated laminate (5) in which a plurality of fiber sheets (9) are laminated, and
The matrix resin (7) cured in a state of being impregnated in the impregnated laminate (5) is provided.
The matrix resin (7) covers the surface of the impregnated laminate (5) to form a resin surface layer (31), and is located on the resin surface layer (31) side of the impregnated laminate (5). A resin injection molded product having a recess (19, 29) formed on at least one surface of the fiber sheet (9).
In the impregnated laminate (5), a nonwoven fabric (15) is provided at a position adjacent to a surface on which the recesses (19, 29) are formed in the predetermined fiber sheet (9).
The fibers of the nonwoven fabric (15) enter the entire area covered by the nonwoven fabric (15) in the recesses (19, 29).
A resin injection molded product characterized by this. In the resin injection molded product according to claim 1 or 2 .
The impregnated laminate (5) is composed of a plurality of fiber bundles (18) aligned in one direction as the predetermined fiber sheet (9), and a gap between adjacent fiber bundles (18) is provided. Having a strand sheet (17) forming the recess (19),
The nonwoven fabric (15) is a resin injection molded product, characterized in that the nonwoven fabric (15) is adjacent to the surface of the strand sheet (17) on the resin surface layer (31) side. In the resin injection molded product according to claim 3 ,
The impregnated laminate (5) has a biaxially woven cross sheet (13) as the fiber sheet (9).
The cloth sheet (13) constitutes the surface of the impregnated laminate (5) and is covered with the resin surface layer (31).
The matrix resin (7) forming the resin surface layer (31) is a resin injection molded product characterized by being a translucent resin. In the resin injection molded product according to claim 4 ,
The nonwoven fabric (15) is a resin injection molded product characterized in that it is arranged between the strand sheet (17) and the cross sheet (13). In the resin injection molded product according to claim 4 or 5 .
The cross sheet (13) is the predetermined fiber sheet (9), and the recess (29) is formed in the gap between the textures.
The nonwoven fabric (15) is a resin injection molded product, characterized in that the nonwoven fabric (15) is adjacent to the surface of the cloth sheet (13) on the resin surface layer (31) side. In the resin injection molded product according to any one of claims 1 to 6 .
The nonwoven fabric (15) is a resin injection molded product characterized by being made of carbon fiber. In the resin injection molded product according to claim 7 ,
A resin injection molded product characterized in that an acid anhydride-based curing agent is used in the matrix resin (7). An impregnated laminate in which a predetermined fiber sheet (9) is formed by laminating a plurality of fiber sheets (9) and having recesses (19, 29) formed on at least one surface thereof. Preparation steps to prepare for (5) and
A set step in which the impregnated laminate (5) is set in a molding die (103), and the impregnated laminate (5) is placed in a molding space (119) formed by the molding die (103). When,
An impregnation step of injecting a liquid matrix resin (7) into the molding space (119) to impregnate the impregnated laminate (5) after depressurizing the molding space (119).
A curing step of curing the matrix resin (7) impregnated in the impregnated laminate (5) to form a resin surface layer (31) covering the surface of the impregnated laminate (5) with the matrix resin (7). And, including
In the preparation step, an impregnated laminate (5) in which the nonwoven fabric (15) is provided at a position adjacent to the surface on which the recesses (19, 29) are formed in the predetermined fiber sheet (9) is prepared .
In the impregnation step, the fibers of the nonwoven fabric (15) enter the recesses (19,29), and the recesses (19,29) are filled with the fibers of the nonwoven fabric (15) and the resin-rich portion composed of the matrix resin (7). Form only (33)
A method for manufacturing a resin injection molded product. An impregnated laminate in which a predetermined fiber sheet (9), which is formed by laminating a plurality of fiber sheets (9) and having recesses (19, 29) formed on at least one surface, is arranged on the surface side. Preparation steps to prepare for (5) and
A set step in which the impregnated laminate (5) is set in a molding die (103), and the impregnated laminate (5) is placed in a molding space (119) formed by the molding die (103). When,
An impregnation step of injecting a liquid matrix resin (7) into the molding space (119) to impregnate the impregnated laminate (5) after depressurizing the molding space (119).
A curing step of curing the matrix resin (7) impregnated in the impregnated laminate (5) to form a resin surface layer (31) covering the surface of the impregnated laminate (5) with the matrix resin (7). And, including
In the preparation step, an impregnated laminate (5) in which the nonwoven fabric (15) is provided at a position adjacent to the surface on which the recesses (19, 29) are formed in the predetermined fiber sheet (9) is prepared.
In the impregnation step, the fibers of the nonwoven fabric (15) enter the entire area covered by the nonwoven fabric (15) in the recesses (19, 29).
A method for manufacturing a resin injection molded product.

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