JP2021008041A - Method for manufacturing resin molding - Google Patents

Abstract

To provide a resin molding having a high bond strength of a resin member to a base material and high rigidity of the base material even when a pressurization force in molding press is low.SOLUTION: A method for manufacturing a resin molding 10 obtained by joining a resin member 15 to a base material 11 containing a fiber and a thermosetting resin includes a plate-like body formation step of forming a plate-like body 12 having a film 14 of a thermosetting resin provided on a mat 13 composed of fibers and a resin molding formation step of joining the resin member 15 to the plate-like body 12, in which the resin molding formation step executes in order a first press step of pressing the plate-like body 12 with a pair of molds 21 and 25 so that its thickness becomes a thickness T2 smaller than a predetermined thickness T3 before the thermosetting resin is cured, and a second press step of displacing the one mold 21 in a mold-opening direction so as to press the plate-like body 12 with the predetermined thickness T3, and pressing the plate-like body while heating the thermosetting resin until it is cured.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for producing a resin molded product.

Conventionally, as an example of a method for producing a base material containing a fiber and a resin, a resin is formed into a film by spraying or coating on the surface of the fiber formed in a mat shape, and the fiber is impregnated with the film-like resin. There is a method (Patent Document 1). Further, as a method of joining a resin member to a base material containing fibers and a resin, a method of melting the joint surface of the resin member while press-molding the base material to fix the resin member to the base material. Is known (Patent Document 2).

Japanese Unexamined Patent Publication No. 2003-103551 JP-A-2002-205337

In the above-described configuration, for example, when the base material is an interior material for a vehicle and the resin member is a bracket, the interior material for a vehicle is generally set to have a small basis weight for the purpose of weight reduction. There is a situation that the pressure cannot be increased. Therefore, the pressure at the time of hot pressing is low, the impregnation of the resin with the fibers is insufficient, and the bonding strength of the resin member with respect to the base material tends to decrease. Further, when the pressure at the time of hot pressing is low, there is a problem that the rigidity of the base material itself is lowered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to increase the bonding strength of the resin member to the base material and the rigidity of the base material even when the pressure during hot pressing cannot be increased. ..

The present invention for achieving the above object is a method for producing a resin molded article including a base material containing at least fibers and a thermosetting resin and a resin member bonded to the base material, and comprises the fibers. A plate-like body forming step of forming a plate-like body having a film of the thermosetting resin on at least one surface of the mat, and the resin in a pair of molds to be pressed when the plate-like body is press-molded. A resin molded body forming step of joining the resin member to the plate-shaped body by inserting the member to form the resin molded body is included, and the plate-shaped body is formed in the resin molded body forming step. A first pressing step of pressing the thermosetting resin with the pair of molds before the thermosetting resin is cured so that the thickness is smaller than the predetermined thickness of the finished resin molded product, and the predetermined plate-shaped body. At least one of the pair of molds is displaced in the mold opening direction in order to press with a thickness, and a second pressing step of pressing while heating with the pair of molds until the thermosetting resin is cured is executed in order. This is a method for manufacturing a resin molded product.

According to such a method for producing a resin molded body, a coating of thermosetting resin provided on at least one surface of a mat made of fibers is spread over the entire thickness direction of the plate-shaped body by a first pressing step in which a high pressing force is applied. It spreads easily and is impregnated into every corner of the mat. Further, the spread thermosetting resin is cured to a predetermined thickness together with the fibers whose thickness has been restored by the second pressing step in which the pressing force is lower than that in the first pressing step. As a result, the completed resin molded product has a lightweight base material having a low density of fibers and thermosetting resin, and yet has a high bonding strength between the base material and the resin member. Further, since the thermosetting resin is spread over the entire plate-like body, the rigidity of the base material is also improved.

In the first pressing step, it is preferable to press the plate-like body so that the thickness is 50 to 90% of a predetermined thickness (thickness of the base material of the resin molded body in the completed form). If it is smaller than 50%, it becomes difficult for the crushed mat to return to a predetermined thickness, or the crushed fibers become dense, and the fluidity of the thermosetting resin that is about to spread decreases. On the other hand, if it is larger than 90%, the diffusion of the thermosetting resin may be insufficient.

The base material is a door trim that constitutes the interior design surface of the vehicle door, and the resin member is joined to the outdoor surface side of the door trim, and a thermosetting resin coating is applied in the plate-like body forming step. It is preferable to provide at least on the indoor surface side of the door trim. According to such a configuration, the thermosetting resin is surely spread over the entire interior surface constituting the interior design surface of the vehicle door, so that the interior design surface can be beautifully formed.

According to the present invention, a resin molded product having high bonding strength of the resin member to the base material and rigidity of the base material can be obtained even when the pressure during hot pressing cannot be increased.

Schematic diagram showing a door trim with bracket of one embodiment Vertical sectional view showing a plate-like body Explanatory drawing showing a process of installing a bracket between a pair of molds. Explanatory drawing which shows the process of installing a plate-like body between a pair of molds which brackets are installed. Explanatory drawing which shows the 1st press process Explanatory drawing which shows the 2nd press process Explanatory drawing which shows the process of opening a pair of molds and taking out a resin molded article Vertical sectional view showing a plate-like body of another embodiment

One embodiment will be described with reference to FIGS. 1 to 7. In the following description, the upper side of FIGS. 1 and 2 is the front side, and the lower side is the back side. Further, the upper side of FIG. 3 is the upper side, and the lower side is the lower side. The resin molded body manufactured by the manufacturing method according to the present embodiment is a door trim 10 with a bracket that constitutes an indoor design surface of a vehicle door, and as shown in FIG. 1, a plate-shaped base material 11 and a base. It has a resin bracket (an example of a resin member) 15 provided on the back surface side of the material 11. The front side of the base material 11 is the indoor design surface (indoor surface 11A), and the back side is the outdoor surface 11B.

The base material 11 is composed of fibers and a thermosetting resin, and has a plate shape having a predetermined thickness T3 with both ends bent like a crank. The base material 11 has a structure in which the thermosetting resin spreads between the entangled fibers in a relatively low density state. Therefore, the base material 11 is a lightweight member while maintaining a predetermined rigidity.

As the above-mentioned fibers, wood fibers obtained by deweaving wood or the like, bast plant fibers such as kenaf, inorganic fibers such as glass fibers and carbon fibers, synthetic resin fibers and the like can be adopted. Examples of the thermosetting resin include one or a combination of two or more of urethane resin, epoxy resin, unsaturated polyester resin and the like. Of these, urethane resin having foamability is preferably used.

The bracket 15 described above is made of, for example, ABS resin, is formed in advance separately from the base material 11, and is joined to the center of the back surface of the base material 11. The bracket 15 is, for example, a clip seat for attaching a clip for locking the door panel.

Next, the device 20 for manufacturing the bracketed door trim 10 of the present embodiment will be described. As shown in FIG. 3, the device 20 has a pair of molds 21 and 25 for pressing the plate-shaped body 12 described later from the vertical direction to form the bracketed door trim 10 shown in FIG. The pair of molds 21 and 25 are arranged upward, and the upper mold 21 that presses the plate-shaped body 12 from the surface side (upper surface side) that becomes the surface (indoor surface 11A) and the upper mold 21 that presses the plate-like body 12 downward so as to face the upper mold 21. It is composed of a lower mold 25 which is arranged and presses the plate-shaped body 12 from the surface side (lower surface side) which is the back surface (outdoor surface 11B).

The mold surface (lower surface) of the upper mold 21 is composed of an upper base portion 22 located at an end portion and extending in the horizontal direction, and a protruding portion 24 protruding downward from the upper base portion 22 in a flat state. The side surface of the projecting portion 24 is an upper inclined portion 23 that is inclined downward and toward the center side from the upper base portion 22. On the other hand, the mold surface (upper surface) of the lower mold 25 has a shape substantially along the mold surface of the upper mold 21, and is set so as to provide a predetermined distance from the mold surface of the upper mold 21. There is. Specifically, the mold surface (upper surface) of the lower mold 25 is a lower base portion 26 that is located at an end and extends in the horizontal direction, and a recessed portion 28 that is flattened downward from the lower base portion 26. It is configured to have and. The inner surface of the recessed portion 28 is a lower inclined portion 27 that is inclined toward the end portion toward the upper side.

Further, in the center of the recessed portion 28, a bracket holding portion 29 for fitting and holding the bracket 15 described above inward is formed in a state of being further recessed downward from the recessed portion 28. As shown in FIG. 4, the bracket holding portion 29 holds the bracket 15 so that the joint surface 16 with the plate-shaped body 12 (base material 11) described later is exposed in the mold. Further, the bracket holding portion 29 is set to a depth at which the joint surface 16 of the bracket 15 is flush with the recessed portion 28 while the bracket 15 is held.

The upper mold 21 is a movable type that can be moved in the vertical direction with respect to the lower mold 25 by a driving device (for example, an electric motor, an air cylinder, a hydraulic cylinder, etc.) (not shown). On the other hand, the lower mold is not provided with a drive device and is a fixed mold. FIG. 3 shows a state in which the upper mold 21 is moved away from the lower mold 25, that is, a state in which the pair of molds 21 and 25 are open. On the other hand, in FIG. 5, the upper mold 21 moves in the direction approaching the lower mold 25, and the plate-shaped body 12 is pressed by the pair of molds 21 and 25, that is, the pair of molds 21 and 25 are closed. Is shown.

Next, a method of manufacturing the door trim 10 with a bracket of the present embodiment will be described. The method for manufacturing the door trim 10 with a bracket is roughly classified as shown in FIG. 2, in which a thermosetting resin coating 14 is formed by applying or spraying a thermosetting resin onto a mat 13 made of entangled fibers. By the plate-shaped body forming step of forming the formed plate-shaped body 12, and as shown in FIGS. 5 and 6, the bracket 15 is inserted into the pair of molds 21 and 25 and the plate-shaped body 12 is pressed. The resin molded body forming step of joining the bracket 15 to the plate-shaped body 12 is provided. In the present embodiment, the mat 13 uses a kenaf mat, and the thermosetting resin constituting the coating film 14 uses a foamable urethane resin.

<Plate-shaped body forming process>
In the plate-like body forming step, as described above, thermosetting property is applied to one surface of the flat mat 13 (the upper surface and the indoor surface 11A in the present embodiment), which is a plate-like member formed by entwining fibers. A film 14 of a thermosetting resin is formed by applying or spraying the resin (see FIG. 2). In the plate-shaped body 12, the thermosetting resin formed in the form of a coating film 14 has not yet solidified, and is in a state of being biased toward the surface of the mat 13. The thickness of the plate-shaped body 12 at this time is T1. The thickness T1 of the plate-shaped body 12 is made larger than the thickness T3 of the base material 11 in the completed form (T1> T3). The weight ratio between the mat 13 and the coating 14 (thermosetting resin) is, for example, about 1: 1.

<Resin molded body forming process>
After forming the plate-shaped body 12 in the plate-shaped body forming step, the plate-shaped body 12 and the bracket 15 are then joined. At this time, in the present embodiment, the following steps are performed.

<Installation process>
First, as shown in FIG. 3, the bracket 15 is installed on the bracket holding portion 29 of the lower mold 25 of the pair of molds 21 and 25 in the open state. When the bracket 15 is installed on the bracket holding portion 29, its upper surface (joining surface 16 with the plate-shaped body 12) is exposed in the mold of the lower mold 25, and the mold surface of the lower mold 25 (recessed portion 28) is exposed. ) And are said to be flush. Further, the bracket 15 is in a state where there is almost no gap between the bracket 15 and the bracket holding portion 29 when the bracket 15 is installed in the bracket holding portion 29. After the bracket 15 is installed on the bracket holding portion 29, the plate-shaped body 12 is arranged at a predetermined position between the upper mold 21 and the lower mold 25 as shown in FIG. In the present embodiment, the plate-shaped body 12 is arranged so that the surface on which the coating film 14 is formed (the surface to be the indoor surface 111A) is located upward.

<First press process>
As shown in FIG. 4, when the bracket 15 and the plate-shaped body 12 are installed at regular positions in the pair of molds 21 and 25 (device 20), the drive device brings the upper mold 21 closer to the lower mold 25 (the direction (). Move down). Then, the plate-shaped body 12 is heat-pressed by the pair of molds 21 and 25 so that the thickness T2 is smaller than the thickness T3 of the target base material 11 (an example of a predetermined thickness, see FIG. 1). (See FIG. 5). The temperature of the pair of molds 21 and 25 at this time is about 100 ° C. By pressurizing with such a high pressing force, the thermosetting resin in a state of covering the upper surface (the surface to be the indoor surface 11A) of the mat 13 is the opposite surface (the lower surface of the mat 13 and the surface to be the outdoor surface 11B). Spreads to.

The thickness T2 of the plate-shaped body 12 pressed in this first pressing step may be 50 to 90% of the thickness (predetermined thickness) T3 of the base material 11 of the door trim 10 with bracket in the completed form. desirable. If the upper mold 21 is excessively close to the lower mold 25 and the thickness of the plate-like body 12 becomes too small, it becomes difficult for the mat to return to the predetermined thickness T3, or the fibers adhere to each other to eliminate the gap. This is because the thermosetting resin may not be able to spread between the fibers. On the other hand, if the upper die 21 is not sufficiently close to the lower die 25, the gap between the fibers is too large, and the thermosetting resin may not spread sufficiently between the fibers and may remain unevenly distributed near the surface. Because. In the present embodiment, the thickness of the plate-shaped body 12 pressed in the first pressing step is about 2 to 5 mm, and the thickness of the base material 11 of the door trim 10 with bracket in the completed form is about 2.5 to 6 mm. ..

Further, the time for pressing and holding the plate-shaped body 12 so as to be T2 is preferably about several seconds. If the holding time is longer than several seconds, the thermosetting resin is cured, and in the step (moving step) of slightly displaces the upper mold 21 from the lower mold 25 in the mold opening direction described below, the plate This is because the thickness of the body 12 is not restored and the base material 11 having a predetermined thickness T3 cannot be formed.

<Movement process>
Next, the upper mold 21 is slightly moved in the direction away from the lower mold 25 so that the thickness of the plate-shaped body 12 becomes a predetermined thickness which is the thickness T3 of the base material 11 in the completed form (movement step). That is, it is displaced in the mold opening direction. At this time, the resin is sufficiently spread in the mat 13 by the first pressing step, but has not been cured yet, so that the mat 13 is elastically restored with the movement of the upper mold 21, or is a thermosetting resin. It recovers by foaming and the thickness is restored to T3. At this time, the thermosetting resin in the mat 13 spreads uniformly in the mat 13. Hereinafter, the base material 11 is a state in which the thermosetting resin is spread in the mat 13.

<Second press process>
Further, in this state (a state in which the thickness of the base material 11 is set to a predetermined thickness T3), the pair of molds 21 and 25 are held for a predetermined time (see FIG. 6). During this time, the thermosetting resin spread in the base material 11 is cured by the heat in the second pressing step. By curing the thermosetting resin, the bracket 15 and the base material 11 are integrally joined. At this time, since the fibers and the thermosetting resin are in good contact with the joint surface 16 of the bracket 15, high joint strength can be obtained.

<Withdrawal process>
After a predetermined time (time for the resin to cure) has elapsed in the second pressing step, the base material 11 is separated from the pair of molds 21 and 25 (see FIG. 7). In this way, a door trim 10 with a bracket is obtained in which the bracket 15 is joined to the base material 11 having a predetermined thickness T3.

The thickness T3 of the base material 11 at this time is about half the thickness T1 of the plate-shaped body 12 before pressing. Therefore, the relationship between the thicknesses of the plate-shaped body 12 and the base material 11 in each step is T1> T3> T2.

Next, the action and effect will be described. The present embodiment is a method for manufacturing a door trim 10 with a bracket including a base material 11 containing a Kenaf fiber and a foamable urethane resin and a bracket 15 bonded to the base material 11, among the mats 13 made of Kenaf fibers. A plate-shaped body forming step of forming a plate-shaped body 12 having a foamable urethane resin coating 14 on the surface, and a bracket 15 in the upper mold 21 and the lower mold 25 to be pressed when the plate-shaped body 12 is press-molded. A resin molded body forming step of joining the bracket 15 to the plate-shaped body 12 to form the door trim 10 with the bracket by inserting the plate-shaped body 12 is included, and in the resin molded body forming step, the plate-shaped body 12 is in the completed form. The first pressing step of pressing with a pair of upper molds 21 and lower molds 25 before the foamable urethane resin is cured so that the thickness T2 of the bracketed door trim 10 is smaller than the predetermined thickness T3, and the plate-shaped body 12 The upper mold 21 is displaced in the mold opening direction in order to press with a predetermined thickness T3, and the second pressing step of pressing while heating with the upper mold 21 and the lower mold 25 until the foamable urethane resin is cured is executed in order. This is a method for producing a resin molded product.

According to the method for manufacturing the door trim 10 with a bracket, the thermosetting resin coating 14 provided on one surface (front side) of the mat 13 made of fibers is formed into a plate by the first pressing step in which the pressing force is high. It easily spreads over the entire thickness direction of 12 and is impregnated into every corner of the mat 13. Further, the spread thermosetting resin is cured to a predetermined thickness T3 together with the restored fibers by the second pressing step in which the pressing force is lower than that in the first pressing step. As a result, the completed door trim 10 with a bracket is provided with a lightweight base material 11 having a low density of fibers and thermosetting resin, and yet has a high bonding strength between the base material 11 and the bracket 15. Further, since the thermosetting resin is spread over the entire plate-like body 12, the rigidity of the base material 11 is also improved.

In the first pressing step, it is preferable to press the plate-shaped body 12 so that the thickness T2 is 50 to 90% of the predetermined thickness T3 (thickness of the door trim 10 with bracket in the completed form). If it is smaller than 50%, it becomes difficult for the crushed mat 13 to return to a predetermined thickness T3, or the crushed fibers become dense, and the fluidity of the thermosetting resin that is about to spread decreases. On the other hand, if it is larger than 90%, the diffusion of the thermosetting resin may be insufficient.

The base material 11 is a door trim constituting the indoor design surface (indoor surface 11A) of the vehicle door, and the bracket 15 is joined to the outdoor surface 11B side of the door trim, and heat is generated in the plate-like body forming step. A curable resin coating 14 is provided on the indoor surface 11A side of the door trim. According to such a configuration, the thermosetting resin is surely spread over the entire interior surface 11A constituting the interior design surface of the vehicle door, so that the interior design surface can be beautifully formed.

<Other embodiments>
The present invention is not limited to the embodiments described by the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not deviating from the gist other than the following. It can be implemented with various changes.

(1) In the above embodiment, the plate-like body 12 having the structure in which the coating material 14 of the thermosetting resin is provided on the surface of the mat 13 is shown, but the coating material 14 may be provided on the back surface side instead of the front surface. Further, as the plate-shaped body 112, a mat 13 having a thermosetting resin coating 14 formed on both sides thereof may be used (see FIG. 8). With such a configuration, it is possible to realize a high-quality base material 11 in which the thermosetting resin spreads more reliably in the fibers. On the other hand, the configuration in which the coating film 14 is provided on one side is excellent in cycle time.

(2) In addition to the above embodiment, the shape of the base material 11 can be changed as appropriate. In the above embodiment, the base material 11 has a structure in which a flat plate-shaped member is bent, but the present invention is not limited to this. For example, the base material 11 may be a curved bent plate-like member.

(3) Further, the bracket 15 may be another resin member, and the position and number of the bracket 15 to be joined to the base material 11 are not limited to the above embodiment.

(4) The resin molded body is not limited to the door trim 10 with a bracket that constitutes the interior design surface of the vehicle door, and the technique of the present invention can be applied to various molded bodies.

10: Door trim with bracket (resin molded body), 11: base material, 11A: indoor surface, 11B: outdoor surface, 12,112: plate-like body, 13: mat (fiber), 14: coating (resin), 15: Bracket (resin member), 16: Joint surface, 20: Device, 21: Upper mold (mold), 25: Lower mold (mold), 29: Bracket holding part, T2: Thickness smaller than predetermined thickness, T3: Predetermined Thickness

Claims (3)

A method for producing a resin molded product comprising a base material containing at least fibers and a thermosetting resin and a resin member bonded to the base material.
A plate-like body forming step of forming a plate-like body in which a coating of the thermosetting resin is provided on at least one surface of the mat made of the fibers.
When the plate-shaped body is press-molded, the resin member is inserted into a pair of molds to be pressed to join the resin member to the plate-shaped body to form the resin molded body. Including the process
In the resin molded body forming step, the plate-shaped body is pressed by the pair of molds before the thermosetting resin is cured so as to have a thickness smaller than a predetermined thickness of the resin molded body in the completed form. 1 press process and
A second press in which at least one of the pair of molds is displaced in the mold opening direction in order to press the plate-like body to the predetermined thickness, and the plate-shaped body is pressed while being heated by the pair of molds until the thermosetting resin is cured. A method for manufacturing a resin molded product, in which the steps are executed in order. The method for producing a resin molded product according to claim 1, wherein in the first pressing step, the plate-shaped body is pressed so that the thickness thereof is 50 to 90% of the predetermined thickness. The base material is a door trim constituting the interior design surface of the vehicle door, and the resin member is joined to the outdoor surface side of the door trim.
The method for producing a resin molded product according to claim 1 or 2, wherein in the plate-shaped body forming step, a coating film of the thermosetting resin is provided at least on the indoor surface side of the door trim.

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