Method for manufacturing composite molded article and composite molded article

A composite molded article is manufactured in such a manner that a molding mold that forms a molding space by mold closing and has a weir portion projecting into the molding space is opened, a flat plate-like first member that is softened under heating is arranged in a part of a portion where the molding space is formed, the stereoscopic first molded portion is formed with mold closing, simultaneously an injected molten resin is filled in a remaining portion of the molding space around the first member outside the weir portion in a state that the weir portion is made to abut against a thin portion provided at a peripheral edge of the first molded portion, and the second molding portion joined to the first molding portion is formed by hardening molten resin after the resin is caused to contact the first molded portion.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method for manufacturing a composite molded article provided by integrally molding different materials and the composite molded article.

Description of the Related Art

An interior material for a vehicle, such as a door trim, the decorativeness of which is improved by forming a grained groove in an interior material main body and fitting and mounting a peripheral edge portion of a skin material such as a nonwoven fabric into the grained groove has been proposed (Patent Document 1). A technology in Patent Document 1 involves providing insertion holes in a bottom portion of the grained groove of the interior material main body, providing, on the skin material, extension portions that are inserted through the insertion holes, and mounting the extension portions inserted through the through-holes and projecting to the back side of the interior material main body on a back surface of the interior material main body.

With the technology in Patent Document 1, an operator however inserts the extension portions of the skin material through the insertion holes of the grained groove, and then, mounts the extension portions on the back side of the interior material main body. Since the plurality of extension portions and insertion holes are provided along the grained groove, the operator needs to perform a mounting operation for each of the extension portions. This requires troublesome tasks and time, resulting in the problem that cost is increased. Furthermore, the technology in Patent Document 1 has the problem that the interior material is heavy because the interior material main body is present also on the back side of the skin material.

On the other hand, a method in which a skin material the outer periphery of which has been previously molded and trimmed in another process is set in a molding mold and a back surface of the skin material is also filled with molten resin for integral molding (so-called insert molding) has been known as a method for an interior material for a vehicle. However, the skin material is thermally damaged by heat of the molten resin injected onto the back surface of the skin material in such insert molding. The problem therefore arises that a material to be used for the skin material is limited to that having heat resistance so as to prevent it from being thermally damaged.

To cope with the above problems, an article provided by integrally molding a multilayered structure with a skin material covered on the surface thereof and a resin single product has been proposed (Patent Document 2). The technology in Patent Document 2 involves setting, in an injection mold, of a structure provided by bonding the skin material onto the surface of a foamed resin sheet with a heat insulating layer interposed therebetween and injection molding on the back surface of the foamed resin sheet, and injection molding of the resin single product. This configuration tries to avoid thermal damage on the skin material due to injection of the molten resin on the back surface by the heat insulating layer.

However, the above-described insert molding and the technology in Patent Document 2 fails to achieve sufficient reduction in weight due to presence of the resin because the resin is provided on the back surface of the skin material. In addition, for example, in the case where the foamed resin sheet or the skin material is replaced by a nonwoven fabric in the above-described insert molding or the technology in Patent Document 2, when the molten resin is injected onto the back surface of the nonwoven fabric, the molten resin leaks out to the surface through the nonwoven fabric by an injection pressure thereof, resulting in deterioration in outer appearance.Patent Document 1: Japanese Patent Application Laid-open No. 2012-111371Patent Document 2: Japanese Patent Application Laid-open No. 2006-159872

SUMMARY OF THE INVENTION

In view of the above-described circumferences, an object of the present invention is to provide a method for manufacturing a composite molded article reduced in weight and having high decorativeness while suppressing increase in cost, and the composite molded article.

In order to achieve the above-described object, a method for manufacturing a composite molded article according to an aspect of the present invention is “a method for manufacturing a composite molded article in which a first molded portion formed by a flat plate-like first member which is softened under heating and a second molded portion formed by hardening molten resin are integrally molded, the method comprising:opening a molding mold that forms a molding space by the mold closing and has a weir portion projecting into the molding space,arranging the flat plate-like first member softened under heating in a part of a portion where the molding space is formed,forming the first molded portion that is stereoscopic with mold closing,simultaneously filling an injected molten resin in a remaining portion of the molding space around the first member outside the weir portion in a state that the weir portion is made to abut against a thin portion reduced in thickness and provided at a peripheral edge of the first molded portion, andforming the second molded portion that is joined to the first molded portion by hardening molten resin after the resin is caused to contact the first molded portion.

Examples of the “first member” which is softened under heating can include a nonwoven fabric containing thermoplastic fiber, a nonwoven fabric impregnated with thermoplastic resin, foamed resin such as urethan foam, and the above-described nonwoven fabric or foamed resin having a surface to which a resin sheet with a woodgrain pattern or a leather pattern applied is bonded.

The “thin portion” may be formed to have a constant width from the peripheral end side of the first molded portion or may be formed into a groove shape in a portion with a constant distance to the inner side of the first molded portion from the peripheral end side of the first molded portion. The “thin portion” may be formed by the weir portion of the molding mold or may be previously formed on the first member.

The molten resin may be injected during the mold closing of the molding mold or after the molding mold is completely closed.

The method for manufacturing the composite molded article with this configuration can mold the flat plate-like first member into the stereoscopic first molded portion by arranging the first member softened under heating in a part of the portion of the opened molding mold where the molding space is formed and the molding mold is closed. Furthermore, simultaneously with molding of the first molded portion, the molten resin injected to the remaining portion of the molding space formed around the first molded portion (first member) flows in the molding space and makes contact with the peripheral edge of the first molded portion. In this case, the thin portion formed by compressing the first member is formed and a density is increased at the peripheral edge of the first molded portion, and the weir portion of the molding mold abuts against the thin portion. The molten resin and heat of the molten resin is not therefore transferred to the inner side of the first molded portion beyond the thin portion and the weir portion. When the molten resin filling the portion of the molding space outside the weir portion is cooled to be hardened, the second molded portion is formed. In such a manner, the composite molded article including the first molded portion and the second molded portion that are integrally molded is manufactured.

As described above, with this configuration, the first molded portion formed by the first member which is softened under heating and the second molded portion made of resin which is molten are integrally molded simultaneously in one molding mold. An operator is not therefore required to assemble the first molded portion and the second molded portion that are separately molded. Accordingly, time taken for manufacturing can be shortened, and increase in manufacturing cost can be suppressed.

Moreover, with this configuration, the thin portion and the weir portion can prevent the molten resin and the heat of the molten resin from influencing the first molded portion. This can avoid deterioration in outer appearance, which is caused by the resin of the second molded portion that appears on the surface of the first molded portion or change of the first molded portion due to the heat of the molten resin. The composite molded article with high decorativeness can thereby be manufactured.

Furthermore, with this configuration, the second molded portion is joined in the portion in contact with the first molded portion, so that the first molded portion and the second molded portion are joined over the entire length of the contact portion. The first molded portion and the second molded portion can thereby be firmly joined in comparison with the case where the skin material is mounted on the interior material main body at places by the extension portions as in Patent Document 1, thereby manufacturing the composite molded article with high strength and rigidity.

Additionally, with this configuration, the first molded portion is formed by the first member softened under heating with mold closing, and the second molded portion is formed by hardening the molten resin. The hardening of the molten resin takes time and the second molded portion is formed later than the first molded portion because the temperature of the molten resin is higher than the temperature of the first member that is not liquefied. Compression stress therefore acts from the surrounding on the first molded portion formed first with contraction of the second molded portion by hardening of the molten resin, so that residual stress is generated on the first molded portion. Therefore, even when an external force acts on the composite molded article, the residual stress of the first molded portion can cancel such force to some extent, thereby manufacturing the composite molded article that is hardly damaged.

Furthermore, with this configuration, the molten resin is injected to the surrounding of the first molded portion to mold the second molded portion, and the second molded portion is not present on the back surface of the first molded portion. Accordingly, as compared to a conventional article in which resin is present on the back surface of a skin material or a decorative material corresponding to the first member, the composite molded article further reduced in weight can be manufactured, and the amount of resin to be used can be reduced for the size of the composite molded article to suppress increase in cost for manufacturing the composite molded article.

In the method for manufacturing the composite molded article in the aspect of the present invention, in addition to the above-described configuration,“the molding mold includes a front mold for forming a front surface of the composite molded article and a back mold for forming a back surface of the composite molded article,the first member has a plurality of tabs extending to a region where the second molded portion is formed, andmold closing is performed in a state where the tabs are positioned to the back mold such that a part of the molding space is formed between the tabs and the front mold.”

A position of the first member arranged in the molding mold can deviate in manufacturing of the composite molded article. When the first molded portion of the composite molded article has a mounting hole or an opening for mounting another component, the first member can be positioned to the molding mold utilizing the mounting hole or the like. It is however difficult to position the first member to the molding mold when the first molded portion has no mounting hole and no opening.

With this configuration, the plurality of tabs are provided on the first member, and the tabs are positioned to the back mold. The first member can therefore be positioned to the molding mold with the plurality of tabs reliably. Furthermore, the tabs extending to the second molded portion are positioned to the back mold, and a part of the molding space is formed between the tabs and the front mold. Accordingly, the molding space is filled with the molten resin to prevent the tabs from appearing on the surface of the second molded portion, and the outer appearance of the composite molded article is not deteriorated.

A composite molded article according to another aspect of the present invention “comprises:a first molded portion that has a thin portion reduced in thickness at a peripheral edge and is stereoscopically formed by a first member which is softened under heating, anda second molded portion that is joined to the first molded portion on an outer side of the thin portion, is provided around the first molded portion, and is formed by hardening molten resin.”

The composite molded article having this configuration can provided similar action and effects to those by the composite molded article manufactured by the above-described method for manufacturing the composite molded article.

As described above, the method for manufacturing the composite molded article reduced in weight and having high decorativeness while suppressing increase in cost, and the composite molded article can be provided as effects of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a composite molded article1as a specific embodiment of the present invention will be described in detail with reference to the drawings. The composite molded article1in the embodiment is used as an interior material for a building, a vehicle, or the like. Herein, a surface that can be externally viewed is referred to as a front surface and an opposite surface thereto is referred to as a back surface when the composite molded article1is mounted on a mounting target.

As illustrated inFIGS.1, the composite molded article1includes a first molded portion3formed by a flat plate-like first member2which is softened under heating and a second molded portion4formed by hardening molten resin. The composite molded article1includes the second molded portion4provided so as to surround the first molded portion3. Each of the first molded portion3and the second molded portion4has a plate-like shape having a constant thickness and is stereoscopically formed. The first molded portion3and the second molded portion4are integrally joined in a joining portion5where they are in contact with each other.

In the composite molded article1in the embodiment, the first member2forming the first molded portion3is a flat plate-like nonwoven fabric which is softened under heating and contains thermoplastic fiber such as polypropylene, polyester, polyethylene, polyethylene terephthalate (PET), and nylon. The second molded portion4is made of thermoplastic synthetic resin such as polypropylene.

The first molded portion3and the second molded portion4respectively have a first joining piece3aand a second joining piece4athat are bent to the back surface side in the joining portion5, and are joined in a state where portions thereof from halfway points of the first joining piece3aand the second joining portion4ato the front ends thereof are in contact with each other. The synthetic resin forming the second molded portion4permeates the first molded portion3made of the nonwoven fabric in the joining portion5, so that the first molded portion3and the second molded portion4firmly adhere to each other.

The first joining piece3aand the second joining piece4aare separated from each other from the front surface to the joined portion, and a groove6is formed between the first joining piece3aand the second joining piece4a. That is to say, the first molded portion3and the second molded portion4are joined to each other at a site deeper than (farther from the front surfaces thereof than) the bottom of the groove6. The groove6extends over the entire length of the peripheral edge of the first molded portion3. The composite molded article1thereby has such outer appearance that the peripheral edge of the first molded portion3is fitted into a grained groove.

The first molded portion3has a thin portion3breduced in thickness at a peripheral edge thereof. As is described in detail, the thin portion3bis provided at a root portion of the first joining piece3a, which is bent to the back surface side and extends in an axial line direction coupling the front surface and the back surface thereof. The thin portion3bis formed by compressing the first member2and has a higher density than that of the other portions. The first molded portion3is joined to the second joining piece4aof the second molded portion4in a portion of the first joining piece3aon the outer side of the thin portion3b(seeFIG.10).

The first molded portion3has flat plate-like tabs3cextending to the back surface of the second molded portion4from the front end of the first joining piece3aand through-holes3dpenetrating through the tabs3c. The plurality of tabs3care provided with intervals along the peripheral edge and respectively have the through-holes3dprovided in a circularly punched form (seeFIG.2). The tabs3care bent to the back surface of the second molded portion4from the first joining piece3aat the bottom portion of the groove6.

Positioning bushes7are fitted into the through-holes3dof the tabs3c. Each of the positioning bushes7has a cylindrical portion7ahaving a circular cylinder shape and a flange portion7bextending outward on one end portion of the cylindrical portion7ain the axial direction (seeFIG.5A). The positioning bushes7are fitted into the through-holes3din a state where the flange portions7babut against the surfaces of the tabs3c. The positioning bushes7in the embodiment are made of synthetic resin.

The tabs3cand the positioning bushes7are joined to the second molded portion4in a state where the surfaces thereof are in contact with the back surface of the second molded portion4(seeFIG.1D). The tabs3cand the positioning bushes7are not thereby seen from the front surface side. Furthermore, the positioning bushes7are not detached to the back side through the through-holes3d. As illustrated in the drawings, the first molded portion3is formed such that the thicknesses of the first joining piece3aand the tabs3care smaller than that of the other portions by compression.

As described above, the second molded portion4is provided so as to surround the first molded portion3and is made of the synthetic resin. Although not illustrated in the drawings, a reinforcing rib may be integrally provided on the back surface of the second molded portion4.

Next, a method for manufacturing the composite molded article1will be described. The composite molded article1is manufactured using a molding mold10as illustrated inFIGS.3A to3Cand the like. The molding mold10is configured by a front mold11for forming the front surface of a product and a back mold12for forming the back surface thereof. The molding mold10forms a molding space13for forming the composite molded article1by mold closing. In the embodiment, the front mold11is an upper mold whereas the back mold12is a lower mold.

A joining portion formation groove14is formed in a portion of the back mold12of the molding mold10, which corresponds to the peripheral edge of the first molded portion3. A weir portion15projecting so as to be inserted into the joining portion formation groove14of the back mold12is formed on the front mold11. In the embodiment, the joining portion formation groove14and the weir portion15are provided in annular forms.

The back mold12includes tab accommodation grooves16extending outward from the joining portion formation groove14and positioning pins17projecting upward from bottom portions of the tab accommodation grooves16(seeFIGS.5B to5E). The tab accommodation grooves16are formed to have such sizes that they can accommodate the tabs3cof the first molded portion3. The plurality of tab accommodation grooves16and positioning pins17are provided with intervals along the joining portion formation groove14. The depths of the tab accommodation grooves16may be the same as, shallower than, or deeper than the depth of the joining portion formation groove14.

Although not illustrated in the drawings, the molding mold10(back mold12) includes a gate for injecting (discharging) the molten resin into the molding space13on the outer side of the joining portion formation groove14in the portion where the molding space13is formed. The molding mold10is used at a predetermined temperature (for example, 35° C. to 45° C.) when the composite molded article1is molded.

The composite molded article1is manufactured in such a manner that first, a flat plate-like base member (nonwoven fabric herein) which is softened under heating is cut into a shape corresponding to the outer shape of the first molded portion3to form the first member2, as illustrated inFIG.2. At this time, the first member2is formed into a shape when the stereoscopic first molded portion3is developed on a plane because the first molded portion3has a stereoscopic shape. Furthermore, the tabs3cextending outward from the peripheral edge and the through-holes3dare formed on the first member2. The tabs3cand the through-holes3dare provided at positions corresponding to the tab accommodation grooves16and the positioning pins17of the back mold12.

In a state where the molding mold10is opened, the flat plate-like first member2softened under heating by a heater of a predetermined temperature (for example, 160° C. to 230° C.) is positioned between the front mold11and the back mold12and arranged in a part of the portion where the molding space13is formed. To be specific, the first member2is placed in a region for forming the first molded portion3, which is surrounded by the joining portion formation groove14of the back mold12, in a region of the molding mold10where the molding space13is formed. At this time, the tabs3cof the first member2are inserted into the corresponding tab accommodation grooves16, and the positioning pins17are inserted through the through-holes3d. The positioning bushes7with the flange portions7bfacing upward are fitted into the through-holes3dand the positioning pins17from above the tabs3c, and the tabs3care pressed against the bottom portions of the tab accommodation grooves16by the flange portions7bfor fixing (seeFIGS.5B and5C). The tabs3care compressed to be thinner than the other portions at this time.

In this manner, the tabs3care inserted into the tab accommodation grooves16and are fixed by the positioning bushes7, so that the first member2is positioned at a fixed position on the back mold12. In this state, the peripheral edge of the first member2is located above the joining portion formation groove14. Then, after the front mold11is lowered and mold closing is started, injection, from the gate, of the molten resin at a higher temperature (for example, 180° C. to 300° C.) than that of the first member2into the remaining portion of the molding space13on the outer side of the joining portion formation groove14is started.

The first member2is pressed against the back mold12by the front mold11with mold closing, and the first member2is formed into the same shape as the molding space13, so that the stereoscopic first molded portion3is formed. At this time, the first member2is cooled and solidified because the usage temperature of the molding mold10is set to 35° C. to 45° C. When the weir portion15of the front mold11abuts against the first member2by the mold closing, the peripheral edge of the first member2is bent to the joining portion formation groove14at the lower side to form the first joining piece3a, and the root portion of the first joining piece3ais compressed rather than the other portions to form the thin portion3b. The weir portion15is thereby made into a state of abutting against the thin portion3b. When the weir portion15presses the peripheral edge of the first member2into the joining portion formation groove14, the peripheral edge of the first member2is compressed and the first joining piece3abecomes thinner than the other portions.

The molten resin injected from the gate expands while flowing in the molding space13on the outer side of the joining portion formation groove14. The molten resin that has reached the joining portion formation groove14makes contact with a portion of the first joining piece3aof the first member2on the front end side of the thin portion3b. On the other hand, the molten resin does not make contact with an inner portion of the first member2inside from the thin portion3bwith presence of the weir portion15of the front mold11, which abuts against the thin portion3b.

The molten resin that has made contact with the portion of the first joining piece3aon the front end side of the thin portion3bpermeates into that portion. Note that the thin portion3bis formed by compressing the first member2and is therefore increased in density. The molten resin does not therefore permeate to the inner side of the first member2beyond the thin portion3b. Accordingly, the molten resin does not ooze out to the surface of the first member2.

Furthermore, also at the sites of the tabs3cin the first member2, the weir portion15of the front mold11abuts against a portion of the first member2on the inner side from the roots of the tabs3c, and a part of the first joining piece3ais formed and the thin portion3bis formed. Then, when the molten resin reaches sites above the tabs3cin the molding space13, the molten resin makes contact with the surfaces of the tabs3cand permeates the tabs3c. Similarly to the above description, the thin portion3band the weir portion15prevents the molten resin from permeating to the inner side from the thin portion3bin the first member2.

At this time, the tabs3cdo not go up from the bottom portions of the tab accommodation grooves16because the flange portions7bof the positioning bushes7with the cylindrical portions7afitted with the positioning pins17through the through-holes3dabut against the surfaces of the tabs3c. Accordingly, the tabs3cdo not appear on the front surface of the second molded portion4.

Then, after the molding mold10is completely closed and the temperature of the molten resin filling the molding space13is hardened to some extent, the molding mold10is opened for demolding, and then, the second molded portion4is completely hardened, thereby completing the composite molded article1.

In this case, since the second molded portion4is formed later than the first molded portion3, compression stress acts from the surrounding on the first molded portion3formed first with contraction of the second molded portion4by hardening of the molten resin, so that residual stress is generated on the first molded portion3.

As described above, the method for manufacturing the composite molded article1in the embodiment includes forming the first molded portion3by cold-press molding and forming the second molded portion4by injection molding, and is therefore a novel manufacturing method in which different molding methods are combined.

Although in the above description, the molten resin is injected before the molding mold10is completely closed as the example, the molten resin may be injected after the molding mold10is completely closed.

According to the embodiment, the first molded portion3formed by the first member2which is softened under heating and the second molded portion4made of the resin which is molten are integrally molded simultaneously in one molding mold10. An operator is not therefore required to assemble the first molded portion3and the second molded portion4that are separately molded. Accordingly, time taken for manufacturing can be shortened, and increase in manufacturing cost can be suppressed.

Moreover, according to the embodiment, the thin portion3band the weir portion15can prevent the molten resin and the heat of the molten resin from influencing the first molded portion3. This can avoid deterioration in outer appearance, which is caused by the resin of the second molded portion4that appears on the front surface of the first molded portion3or change of the first molded portion3due to the heat of the molten resin. The composite molded article1with high decorativeness can thereby be manufactured.

Furthermore, according to the embodiment, the weir portion15of the front mold11and the joining portion formation groove14of the back mold12are provided in the annular forms along the peripheral edge of the first molded portion3. The joining portion5where the first molded portion3and the second molded portion4are joined to each other is thereby formed into an annular form. That is to say, the first molded portion3and the second molded portion4are joined over the entire length of the portion where the first molded portion3and the second molded portion4are in contact with each other. With this configuration, the first molded portion3and the second molded portion4can thereby be firmly joined in comparison with the case where a skin material is mounted on an interior material main body at places by extension portions as in a conventional article, thereby manufacturing the composite molded article1with high strength and rigidity.

In addition, according to the embodiment, residual stress is generated on the first molded portion3with contraction of the second molded portion4in manufacturing. Therefore, even when force acts on the composite molded article1, the residual stress of the first molded portion3can cancel such force to some extent, thereby manufacturing the composite molded article1that is hardly damaged.

Furthermore, according to the embodiment, the molten resin is injected to the surrounding of the first molded portion3to mold the second molded portion4, and the second molded portion4is not present on the back surface of the first molded portion3. Accordingly, as compared to a conventional article in which resin is present on the back surface of a skin material or a decorative material corresponding to the first member2, the composite molded article1further reduced in weight can be manufactured, and the amount of resin to be used can be reduced for the size of the composite molded article1to suppress increase in cost for manufacturing the composite molded article1.

Moreover, according to the embodiment, the first molded portion3with the back surface on which no second molded portion4is present is formed by the nonwoven fabric. Therefore, when the composite molded article1is used for an interior material of a vehicle, sound in the vehicle can be made to escape to the vehicle body side through the first molded portion3, thereby reducing noise in the vehicle.

In addition, according to the embodiment, the plurality of tabs3care provided on the first member2, and the tabs3care positioned to the back mold12. The first member2can therefore be positioned to the molding mold10with the plurality of tabs3creliably. Furthermore, the tabs3cextending to the second molded portion4side are positioned to the back mold12, and a part of the molding space13is formed between the tabs3cand the front mold11. Accordingly, the molding space13is filled with the molten resin to prevent the tabs3cfrom appearing on the front surface of the second molded portion4, and the outer appearance of the composite molded article1is not deteriorated. That is to say, the composite molded article1with high decorativeness and preferable outer appearance can be provided.

Moreover, according to the embodiment, as a configuration for positioning the tabs3cof the first member2to the back mold12, the tab accommodation grooves16are provided and the positioning pins17projecting from the bottom portions thereof are provided on the back mold12. This configuration is relatively simple, so that increase in cost for the molding mold10can be suppressed. In addition, according to the embodiment, the positioning bushes7made of the synthetic resin are used for positioning of the tabs3cof the first member2. The positioning bushes7are relatively inexpensive, so that increase in cost for manufacturing can be suppressed.

Hereinbefore, the present invention has been explained using the preferred embodiment. The present invention is not however limited to the above-described embodiment, and various improvements and changes in design can be made in a range without departing from the aspect of the present invention. Hereinafter, the same reference numerals denote the same components as those in the above description, and overlapped explanation thereof is omitted.

For example, the nonwoven fabric containing the thermoplastic fiber is used as the first member2in the above-described embodiment. The first member2is however not limited thereto, and a nonwoven fabric impregnated with thermoplastic resin, foamed resin such as urethan foam, the above-described nonwoven fabric or foamed resin having a surface to which a resin sheet with a woodgrain pattern or a leather pattern applied is bonded, or the like may be used therefor.

Furthermore, in the joining portion5between the first molded portion3and the second molded portion4, the peripheral edges thereof are bent to the back side, and they are joined to each other at the deeper position than the bottom of the groove6in the above-described embodiment. They are not however limited to be joined thereat and may be joined at a shallower position than the bottom of the groove6, as illustrated inFIGS.6A to6C. In the joining portion5inFIGS.6A to6C, the weir portion15of the front mold11and the joining portion formation groove14of the back mold12form the first joining piece3athat is bent so as to project to the back side in a U-shaped form at the peripheral edge of the first molded portion3(first member2), and the second joining piece4aof the second molded portion4is joined to the front end side of one of two parallel sides of the U shape of the first joining piece3a, which is farther from the center of the first molded portion3.

The embodiment illustrated inFIGS.6A to6Ccan also provide similar action and effects to those in the above description. In addition, since the first molded portion3and the second molded portion4are joined to each other at the shallower position than the bottom of the groove6, the projecting length of the joining portion5to the back side can be shortened. Accordingly, the composite molded article1in which the joining portion5hardly obstacles mounting on a mounting target such as a vehicle can be provided.

The tabs3care positioned into the tab accommodation grooves16of the back mold12using the positioning bushes7in the above-described embodiment. The tabs3care not however limited to be positioned in this manner and may be positioned using fasteners30as illustrated inFIGS.7A to7E. In an example ofFIGS.7A to7E, positioning holes18for mounting the fasteners30are provided in the bottom portions of the tab accommodation grooves16of the back mold12. Each fastener30is configured by a cylindrical grommet31and a pin32. The cylindrical grommet31has a plurality of expandable leg portions31a. The pin32has a flat plate-like pusher32aand its front end is inserted into the grommet31. In the embodiment, when the pushers32aof the pins32are pressed in a state where the grommets31of the fasteners30are inserted into the positioning holes18of the back mold12through the through-holes3dof the tabs3c(seeFIG.7B), the tabs3care pressed and compressed against the bottom portions of the tab accommodation grooves16by the pushers32a, and the leg portions31aof the grommets31are expanded by the pin32to abut against the positioning holes18. The tabs3ccan thereby be positioned (seeFIG.7C).

The embodiment illustrated inFIGS.7A to7Ecan also provide similar action and effects to those in the above description. Furthermore, in the embodiment, as illustrated inFIG.7E, the fasteners30are buried in the composite molded article1, and portions of the fasteners30, which project to the back side from the tabs3c, may be removed after demolding from the molding mold10.

The tabs3care positioned into the tab accommodation grooves16of the back mold12using the positioning bushes7or the fasteners30in the above-described embodiment. The tabs3care not however limited to be positioned in this manner and may be positioned using clamps35as illustrated inFIGS.8A to8D. The clamps35are formed to have such sizes that spaces accommodating the tabs3cin compressed states can be formed between the lower surfaces thereof and the bottom portions of the tab accommodation grooves16when the clamps35are fitted into the tab accommodation grooves16. The clamps35are made of metal that is the same as that forming the molding mold10.

In the embodiment, the diameters of the positioning pins17projecting from the bottom portions of the tab accommodation grooves16are the same as the diameters of the through-holes3dof the tabs3c. Accordingly, when the positioning pins17are fitted into the through-holes3dof the tabs3c, the tabs3c(first member2) are positioned. Then, the clamps35are fitted into the tab accommodation grooves16from above and press and compress the tabs3cto cause the upper surfaces of the clamps35to coincide with the upper surface of the back mold12(seeFIG.8B).

The molding space13having the same thickness as that of the other portion of the second molded portion4is formed above the clamps35. Subsequently, the first molded portion3is formed by mold closing of the molding mold10, the second molded portion4is formed by injection of the molten resin, and the mold opening is performed for demolding. Thereafter, the clamps35are detached from between the tabs3cand the second molded portion4, thereby completing the composite molded article1(seeFIG.8D).

The embodiment illustrated inFIGS.8A to8Dcan also provide similar action and effects to those in the above description. In addition, the thickness of the portions of the second molded portion4, which correspond to sites where the tabs3care provided, can be set to that of the other portion. Therefore, generation of sinks due to hardening of the molten resin on the surfaces of the portions can be suppressed, so that the composite molded article1with preferable outer appearance can be provided. Since the tabs3care not joined to the second molded portion4in the composite molded article1, the tabs3cmay be removed after demolding. Although the clamps35are separated from the molding mold10herein, the configuration is not limited thereto and the clamps35may be opened and closed by inclined pin mechanisms, hydraulic cylinders, or the like.

Furthermore, in the above-described embodiment, the tabs3care positioned to the tab accommodation grooves16of the back mold12using the through-holes3din the punched form, which are provided in the tabs3cof the first member2. The tabs3care not however limited to be positioned in this manner and may be positioned by providing notches3ein the tabs3c, as illustrated inFIG.9A. To be specific, the notches3ethat linearly extend in the direction orthogonal to the peripheral edge of the first member2are provided in the tabs3cof the first member2.

On the other hand, movable pins40each having, at the upper end thereof, a hook portion41the cross-sectional shape of which is an L shape are provided at sites of the tab accommodation grooves16on the back mold12of the molding mold10. The movable pins40are provided so as to be moved up and down and rotate with drive mechanisms (not illustrated). Although not illustrated in the drawings, the movable pins40have columnar shapes. The back mold12includes a cover portion19extending toward the movable pins40on the same plane as the upper surface of the back mold12above portions of the tab accommodation grooves16on the side of the center of the second molded portion4relative to the movable pins40. Spaces between the bottom portions of the tab accommodation grooves16and the cover portion19are formed to have such heights that the first member2(tabs3c) can be inserted thereinto.

In the embodiment ofFIGS.9A to9G, when the first member2is positioned to the opened molding mold10, as illustrated inFIG.9B, the movable pins40are moved up to cause the hook portions41to be located above the upper surface (surface for forming the back surface of the second molded portion4) of the back mold12and the openings of the hook portions41are made to face the direction farther from the joining portion formation groove14. In this state, the movable pins40are inserted through the notches3eof the tabs3cto cause the tabs3cto be locked by the hook portions41(seeFIG.9C). Then, the movable pins40are moved down to cause the upper surfaces of the movable pins40to coincide with the upper surface of the cover portion19(seeFIG.9D). In this state, the tabs3cabut against the bottom portions of the tab accommodation grooves16to be compressed.

Subsequently, when the movable pins40are caused to rotate by 180 degrees about the axial cores thereof, the openings of the hook portions41face the direction of the joining portion formation groove14, the tabs3care pulled in the direction of being farther from the joining portion formation groove14through the notches3eby vertically extending portions of the L-shaped hook portions41, and the front ends of the tabs3care inserted into between the bottom portions of the tab accommodation grooves16and the cover portion19(seeFIG.9E). The tabs3care thereby positioned and are made into states of being incapable of going up from the bottom portions of the tab accommodation grooves16.

Thereafter, the molding mold10is closed to form the first molded portion3, and the molten resin is injected into the molding space13to form the second molded portion4. Then, the mold opening is performed, the movable pins40are moved up, and demolding is performed to cause the hook portions41to be disengaged from the notches3eof the tabs3c, thereby completing the composite molded article1(seeFIG.9G). In demolding, the movable pins40may be moved up after being caused to rotate by 180 degrees about the axial cores thereof.

The embodiment illustrated inFIGS.9A to9Gcan also provide similar action and effects to those in the above description. In addition, the thickness of the portions of the second molded portion4, which correspond to the sites where the tabs3care provided, can be set to that of the other portion. Therefore, generation of sinks due to hardening of the molten resin on the surfaces of the portions can be suppressed, so that the composite molded article1with preferable outer appearance can be provided. Also in the embodiment, similarly to the embodiment ofFIGS.8A to8D, since the tabs3care not joined to the second molded portion4in the composite molded article1, the tabs3cmay be removed after demolding.

Furthermore, in the joining portion5between the first molded portion3and the second molded portion4, they are joined to each other in the state where the peripheral edges thereof are bent to the back side, in the above-described embodiment. The configuration is however not limited thereto, and they may be joined in a state where they are not bent to the back side in the joining portion5, as illustrated inFIGS.10A to100andFIGS.11A to11C. In the embodiments ofFIGS.10A to100andFIGS.11A to11C, when the flat plate-like base member is cut to form the first member2, the front end side including a portion where the groove6is formed in the composite molded article1is compressed to form a thin plate portion3f.

First, in the embodiment ofFIGS.10A to100, auxiliary pieces20extending downward in flat plate forms are provided on the front mold11of the molding mold10on the side on which the surface of the second molded portion4is formed relative to the weir portion15. The plurality of auxiliary pieces20are provided with intervals along the weir portion15. The auxiliary pieces20extend downward shorter than the weir portion15. On the other hand, a step21is formed on the back mold12of the molding mold10between a surface for forming the back surface of the first molded portion3and a surface for forming the back surface of the second molded portion4such that the surface for forming the back surface of the first molded portion3is higher than the surface for forming the back surface of the second molded portion4. The step21is provided on the first molded portion3side from the weir portion15. In the embodiment, the joining portion formation groove14is not provided in the back mold12.

In the embodiment ofFIGS.10A to100, the first member2is positioned on the back mold12such that the base end of the thin plate portion3fis located below the weir portion15, and the molding mold10is closed. At this time, the first member2is pressed to cause the back surface thereof to be formed into a shape along the surface of the back mold12, and the weir portion15presses a part of the thin plate portion3fto form the thin portion3b. The plurality of auxiliary pieces20of the front mold11abut against the thin plate portion3f. Then, the molten resin injected into the molding space13makes contact with the front end of the thin plate portion3fand enters spaces between the auxiliary pieces20to make contact with the surface of the thin plate portion3f, so that it is joined to the first molded portion3. In this case, the plurality of auxiliary pieces20abut against the upper surface of the thin plate portion3f, and the thin plate portion3fdoes not therefore go up even when the molten resin makes contact therewith. The thin portion3band the weir portion15prevent the molten resin from oozing out to the surface of the first member2beyond the thin portion3b.

Thereafter, the molding mold10is opened for demolding, thereby completing the composite molded article1. In the composite molded article1, the first molded portion3is formed to be thinner than the second molded portion4, and the plurality of auxiliary pieces20provided on the front mold11form parting portions4bof the second molded portion4outside the groove6.

In the embodiment ofFIG.10A to100, the step21is provided on the portion of the back mold12of the molding mold10, which corresponds to the joining portion5. The configuration is not however limited thereto, and the surface for forming the back surface of the first molded portion3and the surface for forming the back surface of the second molded portion4may be on the same plane in the portion on the back mold12, which corresponds to the joining portion5, as illustrated inFIGS.11A to11C.

In the embodiment ofFIGS.11A to11C, auxiliary grooves22recessed upward in flat plate forms from the surface for forming the front surface of the second molded portion4are provided on the front mold11of the molding mold10on the second molded portion4side from the weir portion15. The plurality of auxiliary grooves22are provided with intervals along the weir portion15. The depths of the auxiliary grooves22are the same as the thickness of the thin plate portion3fof the first member2. The back mold12of the molding mold10is formed on the same continuous plane with no groove and no step in the portion corresponding to the joining portion5.

Also in the embodiment ofFIGS.11A to11C, the first member2is positioned on the back mold12such that the base end of the thin plate portion3fis located below the weir portion15, similarly to the embodiment ofFIGS.10A to100. When the molding mold10is closed, the weir portion15of the front mold11abuts against the thin plate portion3f, and the molten resin injected into the molding space13makes contact with the front end and the surface of the thin plate portion3f. At this time, the weir portion15presses the thin plate portion3fdownward to form the thin portion3b. The molten resin is thereby prevented from oozing out to the surface of the first member2beyond the thin portion3b. Furthermore, since the thin plate portion3fis formed by compressing the first member2, it has rigidity and is not easily bent. Therefore, the thin plate portion3fdoes not go up from the back mold12even when the molten resin makes contact therewith. The molten resin injected into the molding space13also enters the auxiliary grooves22in the front mold11.

Thereafter, the molding mold10is opened for demolding, thereby completing the composite molded article1. In the composite molded article1, the first molded portion3and the second molded portion4are formed to have the same thickness, and the plurality of auxiliary grooves22provided in the front mold11form parting portions4cprojecting from the surface of the second molded portion4outside the groove6.

As described above, the embodiments ofFIGS.10A to100andFIGS.11A to11Ccan also provide similar action and effects to those in the above description. In addition, the first molded portion3and the second molded portion4are not bent so as to project to the back side in the joining portion5, and the back surfaces thereof in the joining portion5are formed on the same plane. The composite molded article1that is entirely uniform in thickness can thereby be provided.

Furthermore, according to the embodiment, the parting portion4bor the parting portion4cwith irregularities is provided on the second molded portion4outside the groove6. Therefore, the parting portion4bor the parting portion4ccan accentuate the front surface of the composite molded article1to increase the decorativeness. In addition, even when the position of the peripheral edge of the first member2deviates in manufacturing, it can be made less noticeable, so that the composite molded article1with preferable outer appearance can be provided.

Moreover, in the above-described embodiment, the composite molded article1in which nothing is provided on the back surface of the first molded portion3is described. The composite molded article1is not however limited thereto, and a composite molded article50in which a third molded portion8is provided on the back surface of the first molded portion3may be configured, as illustrated inFIGS.12A to12C. In the embodiment, a third molding surface23for forming the third molded portion8is formed on the back mold12of the molding mold10.

The third molded portion8of the composite molded article50is stereoscopically formed simultaneously with the first molded portion3by arranging a flat plate-like third member8amade of foamed resin such as urethan foam, which has been softened under heating, on the third molding surface23of the back mold12of the opened molding mold10, arranging the first member2heated similarly to the above description above the third member8a, and performing mold closing.

According to the embodiment ofFIGS.12A to12C, the composite molded article50having different soundproof performance and heat insulating performance can be easily provided by selecting the thickness and/or the material of the third molded portion8.

In the embodiment ofFIGS.12A to12C, the third member8asoftened under heating forms the third molded portion8. The third molded portion8is not however limited to be formed in this manner and may be formed in the following manner. That is, when the first molded portion3is formed by closing the molding mold10, foamed resin is supplied to between the first member2and the back mold12, the first member2is pressed against the front mold11with pressure of the foamed resin to form the first molded portion3, and the foamed resin is hardened to form the third molded portion8.

In the above-described embodiment, the composite molded article1in which the second molded portion4is integrally molded so as to surround the entire periphery of the first molded portion3. The composite molded article1is not however limited thereto, and a composite molded article in which the second molded portion4is integrally formed so as to surround the periphery of the first molded portion3in a U-shaped form or an L-shaped form.