JP7093229B2 - Manufacturing method of decorative molded product - Google Patents

Description

The present invention relates to a method for manufacturing a decorative molded body using a preform molded body in which a decorative sheet is shaped into a three-dimensional shape.

In-mold molding is known in which a preform molded body in which a decorative sheet is shaped into a three-dimensional shape is placed in a cavity of a mold and injection molded. According to in-mold molding, it is possible to manufacture a decorative molded body in which a decorative sheet is integrated with the surface of the injection molded body.

A method of manufacturing a decorative molded body by in-mold molding using a preform molded body will be described with reference to FIG. In FIG. 5, 23 is a preform molded body, 31 is a female mold, 32 is a male mold, 14 is an injection part main body of an injection molding machine, 14a is a nozzle, 14b is a cylinder, 14c is an inline screw, G is a gate, and 25 is. Injection-molded article, 15 is a molten resin, and 29 is a decorative molded article.

In in-mold molding using a preform molded body, first, as shown in FIG. 5A, a mold 33 composed of a female mold 31 having a cavity portion 31a and a male mold 32 having a core portion 32d. The preform molded body 23 is arranged in the cavity portion 31a of the female mold 31. Then, as shown in FIG. 5B, the female mold 31 and the male mold 32 are molded. The mating surface PL is formed by mold clamping. Then, as shown in FIG. 5C, the cavity 33a formed by molding the female mold 31 and the male mold 32 is filled with the molten resin 15 of the thermoplastic resin from the gate G.

Then, after the cooling step of cooling the molten resin 15 in the mold 33 is completed, as shown in FIG. 5D, the female mold 31 is retracted to open the female mold 31 and the male mold 32. As a result, a decorative molded body 29 in which the preform molded body 23 is integrated with the injection molded body 25 is obtained.

In in-mold molding, the molten resin is injected at a temperature higher than the deflection temperature under load of the material forming the preform molded body, so that the preform molded body is softened and stretched by the heat and flow of the molten resin. , It has been known that wrinkles occur in the preform molded body integrated with the injection molded body. As a method for suppressing the occurrence of such wrinkles, for example, in Patent Document 1 below, in a closed state, the molded product is molded so as to be curved at a portion corresponding to a corner portion of the molded product without contacting the mold. By using a preform molded body whose end surface is punched out so as to be in contact with the mold at a position corresponding to the edge of the inner surface of the rising portion of the molded body, wrinkles are generated in the film integrated with the injection molded body. Disclose that things are suppressed.

Further, although it is not a technique aimed at suppressing the occurrence of wrinkles, for example, Patent Document 2 below corresponds to a boundary line between a male mold and a female mold closed during injection molding, a so-called parting line. It is disclosed that by covering the portion with an insert material, a good-looking insert molded product in which resin burrs and steps do not appear on the parting line can be obtained. However, according to such a method, when the molten resin invades the cavity during injection molding, the parting line is covered with the insert material, which makes it difficult for gas such as air in the cavity to escape from the parting line. It seems that it is easy to cause poor filling of molten resin.

Further, although it is not related to the manufacture of a decorative molded product, Patent Document 3 below describes a resin product in which an intermediate product is molded by a resin molding machine and burrs of the intermediate product are removed by a deburring device to manufacture a finished product. In the manufacturing system, the resin molding machine is provided with a mold having an accommodating portion for accommodating the overflow resin on the mating surface, and the intermediate product in which the overflow resin is integrated is molded by the mold, and the deburring device is intermediate. Disclosed is a resin product manufacturing system for manufacturing a finished product by cutting the overflow resin integrated with the product together with the burr.

Japanese Unexamined Patent Publication No. 2005-104114 Japanese Unexamined Patent Publication No. 6-328498 Japanese Unexamined Patent Publication No. 2010-260337

In in-mold molding, a molten resin that is injected at high speed and high pressure and penetrates into the mold gives a shearing force from the back surface of the preform molded body in the traveling direction of the molten resin in a softened state. At this time, the preform molded body is stretched by applying a shearing force in a softened state. Then, as shown in FIG. 6A, the peripheral edge of the stretched preform molded body 23 collides with the mating surface PL of the mold 33, and the stretched excess portion is folded, and the peripheral edge of the decorative molded body 29 is folded. There was a problem of generating wrinkles w in the vicinity.

Further, in order to suppress the occurrence of wrinkles w in the vicinity of the peripheral edge of the decorative molded body 29 as shown in FIG. 6A, the preform molded body 23 extends during in-mold molding and the peripheral edge thereof is the mating surface PL. In order to avoid collision with the cavity, a method of forming the preform molded body 23 in advance to be smaller than the actual size of the cavity can also be adopted. However, as shown in FIG. 6B, when the preform molded body 23 was too small, the preform molded body 23 sometimes did not stretch so as to sufficiently cover the peripheral edge of the injection molded body 25. In that case, the peripheral edge of the preform molded body 23 becomes shorter than the peripheral edge of the injection molded body 25, and the injection is performed in the vicinity of the peripheral edge of the injection molded body 25 so as to be surrounded by a broken line circle without being covered by the preform molded body. An exposed portion e in which the molded body 25 is exposed may be formed. In addition, such a phenomenon also occurs when the preform molded body housed in the cavity is displaced from an appropriate position. Both the decorative molded body having wrinkles w as shown in FIG. 6A and the decorative molded body having the exposed portion e as shown in FIG. 6B are usually treated as defective products.

In the molding of the decorative molded body by in-mold molding, as described above, the preform molded body is not wrinkled in the vicinity of the peripheral edge of the preform molded body and the injection molded body is not exposed in the vicinity of the peripheral edge. It was difficult to match the peripheral edge of the molding with the peripheral edge of the injection molded product. Therefore, the appearance of the obtained decorative molded body is checked for each shot of in-mold molding, and if wrinkles tend to occur, the appearance is changed to a preform molded body trimmed smaller than usual, and injection is performed. When the peripheral edge of the molded product tended to be exposed without being covered by the preform molded product, it was necessary to make adjustments such as changing to a preform molded product that was trimmed larger than usual. Therefore, there is a problem that the productivity is low and the yield of non-defective products is also low.

According to the present invention, in the production of a decorative molded body by in-mold molding, it is difficult to leave wrinkles on the preform molded body, and it is difficult to generate a portion where the injection molded body is exposed without being covered by the preform molded body. Provided is a method for manufacturing a decorative molded product for stable mass production of the decorative molded product.

One aspect of the present invention is a step of preparing a preform molded body in which a decorative sheet is shaped into a three-dimensional shape, a male mold having a core portion, and a cavity that accommodates the core portion when the mold is molded. A step of arranging a preform molded body in the cavity of a mold having a cavity to be formed and a mold including the cavity, and molding the female and male molds with the preform molded body housed in the cavity. The cavity is provided with a step of molding a decorative molded body made of an injection molded body in which a preform molded body is integrated on the surface by filling the formed cavity with a molten resin and injection molding. The preform molded body includes, a main body forming portion forming the main body portion of the decorative molded body, and a surplus portion forming portion forming a surplus portion thinned from the peripheral edge of the main body portion via a step. This is a method for manufacturing a decorative molded product, which comprises a step of arranging the peripheral edge of the decorative molded product so as to overlap a part of the surplus portion and removing the surplus portion. According to such a manufacturing method, in the production of the decorative molded body, the stretched portion of the preform molded body is arranged so as to overlap the surplus portion at the time of in-mold molding, so that the preform molded body is stretched. The portion can be accommodated in the surplus portion. As a result, the peripheral edge of the preform molded body is less likely to collide with the mating surface PL. Therefore, it is possible to reduce the occurrence of wrinkles formed so that the stretched portion has no place to go and is folded. Further, by arranging the peripheral edge of the preform molded body so as to overlap a part of the surplus portion, it is possible to make it difficult to generate a portion where the injection molded body is exposed without being covered by the preform molded body. Then, by removing the excess portion formed so as to be thinned through the step from the peripheral edge of the main body portion, the peripheral edge of the injection molded body and the peripheral edge of the preform molded body are aligned and the injection molded body is not exposed. The final product, the decorative molded product, can be mass-produced in a stable manner.

Further, it is preferable to remove the surplus portion along the step because it is easy to remove the surplus portion.

Further, it is preferable that the preform molded body does not come into contact with the tip surface of the excess portion forming portion after injection molding, because wrinkles are particularly unlikely to occur.

Further, the preform molded body is arranged so that the peripheral edge thereof overlaps a part of the excess portion forming portion before injection molding, so that it is particularly easy to obtain a decorative molded body of the final product in which the injection molded body is not exposed. It is preferable from.

Further, the step between the main body portion and the surplus portion is 0.5 mm or more, and the thickness of the surplus portion is 0.4 to 1.5 mm, so that the surplus portion maintains an appropriate rigidity and is appropriately high. It is preferable because it is easy to form a step and use the corner to accurately and easily remove the excess portion.

Further, it is preferable that the peripheral edge of the preform molded body overlaps the surplus portion with a width of 0.5 mm or more from the viewpoint that the surplus portion can be easily removed from the decorative molded body so as to form a clean cross section.

Further, the decorative sheet preferably contains a fiber structure. The decorative sheet containing the fiber structure is thicker than the homogeneous resin film, and has poor morphological stability due to the voids inside the fiber structure. The decorative sheet containing such a fiber structure tends to fluctuate in the amount of elongation in in-mold molding. The production method according to the present invention exerts a particularly remarkable effect on a decorative sheet containing a fiber structure in which the amount of elongation is liable to fluctuate.

According to the present invention, in the production of a decorative molded body by in-mold molding, it is difficult to generate a portion where the injection molded body is exposed without leaving wrinkles on the preform molded body and without being covered by the preform molded body. , Decorative molded products can be mass-produced in a stable manner.

FIG. 1 is a schematic cross-sectional view illustrating each step of molding the preform molded body 3 of the embodiment. FIG. 2 is a schematic cross-sectional view illustrating each step of in-mold molding using the preform molded body 3 of the embodiment. FIG. 3 is a partial schematic cross-sectional view of the decorative molded body 10 of the embodiment for explaining the surplus portion. 4 (a) is a schematic perspective view of the process of cutting off the surplus portion 19 from the decorative molded body 10 obtained in the embodiment as viewed from above, and FIGS. 4 (b) and 4 (c) are FIGS. 4 (4). Referencing the schematic cross section of bb'of (a), a schematic cross section for explaining a process of cutting off the surplus portion 19 from the decorative molded body 10 to manufacture the final product, the decorative molded body 20. It is a figure. FIG. 5 is an explanatory diagram illustrating each step of a conventional method for manufacturing a decorative molded body by in-mold molding using a preform molded body. FIG. 6 is an explanatory diagram for explaining a problem caused by a conventional method for manufacturing a decorative molded product.

An embodiment of a method for manufacturing a decorative molded article according to the present invention will be described in detail below with reference to the drawings. The method for manufacturing a decorative molded body of the present embodiment includes a step of preparing a preform molded body in which a decorative sheet is shaped into a three-dimensional shape, a male mold having a core portion, and a core portion when the mold is fastened. The process of arranging the preform molded body in the cavity of the mold provided with the female mold having the cavity portion for accommodating and forming the cavity, and the female mold in the state where the preform molded body is accommodated in the cavity portion. A process of molding a decorative molded body made of an injection molded body in which a preform molded body is integrated on the surface by molding the male mold and filling the formed cavity with a molten resin for injection molding. , Equipped with. The cavity includes a main body forming portion forming the main body portion of the decorative molded body and a surplus portion forming portion forming a surplus portion thinned from the peripheral edge of the main body portion via a step, and is preform molded. The body is arranged so that its peripheral edge overlaps a part of the surplus portion.

First, a process of preparing a preform molded body in which a decorative sheet is shaped into a three-dimensional shape will be described.

The preform molded body is obtained by preform molding in which a decorative sheet is shaped into a three-dimensional shape by a molding means such as hot press molding, vacuum forming, vacuum forming, vacuum forming. The mold used for preform molding is designed so that the outer surface of the obtained preform molded body has a three-dimensional shape that follows the shape of the cavity of the mold used for in-mold molding.

The decorative sheet is not particularly limited as long as it can be preform-molded and is integrated with the surface of the injection-molded article by in-mold molding. Specific examples thereof include fiber structures such as non-woven fabrics, woven fabrics, woven fabrics, and knitted fabrics, leather-like materials such as artificial leather and synthetic leather containing fiber structures, and homogeneous resin sheets. Among these, a fiber structure or a leather-like material containing the fiber structure, in which the effect of the present invention is particularly remarkably exhibited due to poor morphological stability, is particularly preferable. The thickness of the decorative sheet is not particularly limited, but is preferably, for example, about 0.1 to 2 mm, more preferably about 0.2 to 1 mm.

FIG. 1 is an explanatory diagram for explaining each step of hot press molding for molding a preform molded body of a decorative sheet. In FIG. 1, 1 is a decorative sheet, 21 is a male mold for a hot press, 22 is a female mold for a hot press, 21a is a core portion of the male mold 21, and 22a is a cavity portion of the female mold 22. Is. Further, 2 is a preform molded body before trimming, 3 is a preform molded body after trimming, and 4 is an unnecessary portion trimmed from the preform molded body 2.

First, as shown in FIG. 1A, the decorative sheet 1 is arranged between the female mold 22 and the male mold 21. At this time, the female mold 22 and the male mold 21 are heated to a predetermined temperature for softening the decorative sheet 1. Then, as shown in FIG. 1 (b), the female mold 22 and the male mold 21 are molded with a predetermined pressure. At this time, the decorative sheet 1 is sandwiched between the core portion 21a of the male mold 21 and the cavity portion 22a of the female mold 22 and shaped.

Then, as shown in FIG. 1 (c), the female mold 22 and the male mold 21 are opened and cooled to obtain the preform molded body 2 before trimming. Then, as shown in FIG. 1 (d), the preform molded body 2 is taken out from the female mold 22 and the male mold 21, and the unnecessary portion 4 is trimmed to obtain the preform molded body 3. At this time, the preform molded body 3 is sized so as to be arranged in the cavity of the mold used for in-mold molding so that the peripheral edge thereof overlaps a part of the surplus portion described later, as will be described later. Trimmed to. The size of the preform molded body 3 should be trimmed to be larger than that of the decorative molded body of the final product so that the peripheral edge thereof overlaps a part of the surplus portion forming portion of the cavity of the mold used for in-mold molding. It is preferable because it is easy to arrange in.

The preform molded body 3 thus obtained is used for in-mold molding and integrated with the surface of the injection molded body to form a decorative molded body. Next, each step of in-mold molding will be described. FIG. 2 is an explanatory diagram illustrating each step of in-mold molding using the preform molded body 3 of the present embodiment.

In FIGS. 2, 3 is a preform molded body, 5 is an injection molded body, 8 is a sprue runner, 9 is a decorative molded body having a sprue runner 8, and 10 is a decorative molded body from which the sprue runner 8 is removed (as an intermediate body). 11 is a female mold having a concave cavity portion 11a, 12 is a male mold having a core portion 12a, and 13 is a mold formed by molding the female mold 11 and the male mold 12. Reference numeral 14 is an injection part main body of an injection molding machine, 14a is a nozzle, 14b is a cylinder, 14c is an in-line screw, G is a gate, and 15 is a molten resin. Further, the cavity c is formed in the mold 13 formed by molding the female mold 11 and the male mold 12. The cavity c is a main body forming portion c1 for forming the main body 18 of the injection molded body 5 constituting the decorative molded body of the final product, and a surplus removed for manufacturing the decorative molded body of the final product. A surplus portion forming portion c2 for forming the portion 19 is included. The surplus portion forming portion c2 is a portion thinned from the peripheral edge of the main body portion forming portion c1 via the step s. In the present embodiment, the female mold 11 is a movable side mold and the male mold 12 is a fixed side mold. Further, the male mold 12 is provided with an air vent v for removing a gas such as air in the cavity c when the molten resin is injected.

In the method for manufacturing a decorative molded body of the present embodiment, as shown in FIG. 2A, the preform molded body 3 is housed in the cavity portion 11a formed in the female mold 11. At this time, referring to the partially enlarged view surrounded by the broken line circle in FIG. 2B, the peripheral edge 3a of the preform molded body 3 is thinned from the peripheral edge of the main body forming portion c1 via the step s. It is preferable that the portion is arranged so as to be accommodated in the surplus portion forming portion c2, which is a portion of the surplus portion. The peripheral edge is an edge along the end face of the preform molded product. Further, referring to the partially enlarged view surrounded by the broken line circle in FIG. 2 (c), the preform molded body 3 abuts on the tip surface of the surplus portion forming portion c2 after filling the molten resin by injection molding. It is preferable that the size is not large, because wrinkles are less likely to occur. The tip surface of the surplus portion forming portion is a male-shaped mating surface forming the surplus portion forming portion.

When the preform molded body is housed in the cavity, it may be attached to the surface of the cavity with double-sided tape so that the preform molded body will not be displaced even if it is self-adsorbed to the surface of the cavity. , It may be fixed by vacuum suction or by providing a protrusion in the cavity and fitting it into the protrusion.

Next, as shown in FIG. 2B, the female mold 11 and the male mold 12 are molded to form the mold 13 in a state where the preform molded body 3 is housed in the cavity portion 11a. The mold 13 is thinned from the peripheral edge of the main body forming portion c1 for molding the main body 18 of the injection molded body constituting the final product, and the main body forming portion c1 via the step s. Further, a cavity c including a surplus portion forming portion c2 for forming the surplus portion 19 to be removed later is formed. The step s is formed in the core portion 12a so as to separate the main body portion forming portion c1 and the surplus portion forming portion c2. Further, it is preferable that the surplus portion forming portion c2 is formed on the entire circumference of the main body portion forming portion c1.

Referring to the enlarged view surrounded by the broken line circle in FIG. 2B, the preform molded body 3 has its peripheral edge 3a located at the surplus portion forming portion c2 and comes into contact with the mating surface PL when stretched. It is preferable to arrange it in a position that does not prevent it. That is, it is preferable that the preform molded body 3 is trimmed to a size such that the peripheral edge 3a is located at the surplus portion forming portion c2 and does not reach the mating surface PL when stretched. In FIG. 2B, the peripheral edge 3a of the preform molded body 3 is located at the surplus portion forming portion c2, but when the preform molded body is made of a particularly stretchable material, it is not necessarily before injection molding. It is not necessary that the peripheral portion is located at the surplus portion forming portion.

Then, as shown in FIG. 2C, the cavity c is filled with the molten resin 15. Specifically, the injection part main body 14 of the injection molding machine is advanced, the nozzle 14a is brought into contact with the sprue bush of the figure shown in the male mold 12, and the molten resin 15 in the cylinder 14b is injected by the in-line screw 14c. The molten resin 15 is filled in the cavity c. At this time, referring to the partially enlarged view surrounded by the broken line circle in FIG. 2C, the inflow of the molten resin 15 filled in the cavity c at high speed and high pressure on the back surface of the preform molded body 3 causes the inflow of the molten resin 15 into the cavity c. A shear force is applied in the direction of the mating surface PL, which is the flow direction. At this time, the preform molded body 3 is stretched in the flow direction by applying a shearing force in a softened state. At this time, the extended portion is accommodated in the surplus portion forming portion c2. Then, by using the preform molded body 3 trimmed to an appropriate size so that the peripheral edge 3a does not collide with the mating surface PL of the mold, even if the vicinity of the peripheral edge of the preform molded body 3 is extended, the peripheral edge 3a is formed. The stretched part does not sag because it does not collide with the mating surface PL. As a result, wrinkles are suppressed in the vicinity of the peripheral edge of the obtained decorative molded body 9. Further, since the peripheral edge 3a is housed in the surplus portion forming portion c2, the main body portion of the injection molded body 25 is completely covered with the preform molded body 3 and is not exposed.

An air vent v for exhausting a gas such as air in the cavity is formed in the surplus portion forming portion c2 when the molten resin 15 is filled. In in-mold molding, since the preform molded body is arranged in the cavity, it is difficult for the gas in the cavity to be exhausted from the mating surface PL. If the gas in the cavity is difficult to be exhausted, the position of the preform molded body may shift when the molten resin is filled, or the gas may be compressed near the end of the flow to increase the temperature, resulting in resin burning in the decorative molded body. Or have concerns. By providing the air vent v at the tip of the surplus portion forming portion c2, burrs and resin burns generated by the air vent v can be concentrated on the surplus portion forming portion c2 to be removed. Therefore, by removing the surplus portion forming portion c2, burrs generated by resin burning and air vent v can also be removed. The thickness of the air vent is not particularly limited as long as the gas in the cavity is smoothly exhausted with the inflow of the molten resin, but it is preferably about 10 to 50 μm, for example.

Specific examples of the thermoplastic resin to be injected include ABS resin, acrylic resin such as PMMA resin, polystyrene resin, polycarbonate resin, polyolefin resin such as polypropylene, polyethylene terephthalate (PET) and polybutylene. Examples thereof include polyester resins such as terephthalate (PBT), various polyamide resins, and COP resins. Further, these may be a compound product containing a filler or the like, or a mixed product obtained by alloying or blending a plurality of types of resins. These are appropriately selected according to the application. For example, as the resin used for the housing of mobile phones, mobile devices, home appliances and the like, resins having excellent impact resistance such as ABS-based resins, polycarbonate-based resins, and polyolefin-based resins such as polypropylene are preferably used.

The injection molding conditions are conditions that can be completely filled according to the thermal characteristics and melt viscosity of the thermoplastic resin, the shape of the molded body, and the resin thickness (resin temperature, mold temperature, injection pressure, injection speed, holding pressure after injection). , Cooling time) is set appropriately.

Then, after cooling the molten resin 15 in the cavity c for a predetermined time, as shown in FIG. 2D, the female mold 11 and the male mold 12 are opened to form an injection-molded article 5 and an injection-molded article. The decorative molded body 9 composed of the preform molded body 3 laminated and integrated in 5 is taken out. Then, the decorative molded body 10 is obtained by cutting off the sprue runner 8 which is an unnecessary portion formed on the injection molded body 5 of the decorative molded body 9.

FIG. 3 is a partially enlarged view of the decorative molded body 10 for explaining the surplus portion 19. The decorative molded body 10 includes a main body portion 18 formed by the main body portion forming portion c1 and a surplus portion 19 formed by the surplus portion forming portion c2. In FIG. 3, T1 is the thickness of the surplus portion 19, T2 is the thickness of the surplus portion 19 of the portion overlapping the preform molded body 3, T3 is the thickness of the peripheral edge of the main body portion 18, and T4 is the step s. Further, L1 is the length of the surplus portion 19, and L2 is the length of the portion overlapping the surplus portion 19 of the preform molded body 3.

Each dimension shown in FIG. 3 is preferably in the following range, for example. The thickness T1 of the surplus portion 19 is preferably 0.4 to 1.5 mm, more preferably 1 to 1.5 mm, and the thickness of the portion of the surplus portion 19 excluding the portion overlapping the preform molded body 3. T2 is preferably 0.1 to 1 mm, more preferably 0.5 to 1 mm. When T1 and T2 are too thin, the rigidity of the surplus portion 19 is insufficient and it becomes difficult to cut the surplus portion 19 in the step of removing the surplus portion 19 described later, and the surplus portion 19 is melted into the surplus portion forming portion c2 during in-mold molding. There is a tendency that the resin does not easily penetrate and filling defects are likely to occur. Further, when T1 and T2 are too thick, it tends to be difficult to remove the surplus portion 19.

Further, the thickness T3 of the peripheral edge of the main body portion is preferably about 1 to 3 mm. If T3 is too thin, it tends to be difficult to form the step s, and it tends to be difficult to remove the surplus portion 19 along the step s. The T4 of the step s is preferably 0.5 mm or more, more preferably 0.5 to 1.5 mm, and particularly preferably 0.8 to 1.3 mm. If the T4 of the step s is too low, it tends to be difficult to remove the surplus portion 19 along the step s.

Further, the length L1 of the surplus portion 19 is preferably about 2 to 5 mm. If L1 is too short, the stretch margin of the preform molded body 3 becomes short during in-mold molding, so that the peripheral edge 39 of the preform molded body overlaps with the surplus portion 19 unless the dimensional accuracy of the preform molded body is improved. It tends to be difficult. Further, the length L2 of the portion overlapping the surplus portion 19 of the preform molded body 3 is preferably 0.5 mm or more, more preferably 1 to 4.5 mm. If the length L2 of the portion overlapping the surplus portion 19 is too short, it tends to be difficult to accurately remove the portion overlapping the surplus portion 19 of the preform molded body 3 while maintaining a clean end face.

Further, the difference L1-L2 between the length L1 of the surplus portion 19 and the length L2 of the portion overlapping the surplus portion 19 is 0 to 4.5 mm, and further 0.5 to 4 mm for preform molding. Since the peripheral edge of the body does not abut on the tip surface of the surplus portion, wrinkles are particularly unlikely to occur, which is preferable.

By removing the surplus portion 19 from the decorative molded body 10 molded in this way, an injection molded body in which no wrinkles remain in the vicinity of the peripheral edge of the preform molded body and is not covered by the preform molded body can be obtained. A decorative molded product 20 as a final product having no exposed portion can be obtained. With reference to FIG. 4, a step of cutting off the surplus portion 19 from the decorative molded body 10 to finish the decorative molded body 20 will be described.

4 (a) is an explanatory view illustrating a step of cutting off the surplus portion 19 from the decorative molded body 10 when viewed from above, and FIGS. 4 (b) and 4 (c) are shown in FIG. 4 (a). It is a schematic diagram explaining the process of excising the surplus portion 19 with reference to the schematic diagram of the bb'cross section.

As shown in FIG. 4A, the decorative molded body 10 has a main body portion 18 which is a decorative molded body 20 of the final product and a surplus portion 19 which is continuous around the main body portion 18, and the surplus portion 19 is a cutter blade. It is excised at 40. For details, referring to FIG. 4B, the surplus portion 19 is applied while the cutter blade 40 is applied along the corner r forming the step s that separates the main body portion 18 and the surplus portion 19 of the decorative molded body 10. By excising the surplus portion 19, only the surplus portion 19 can be selectively and easily excised. By cutting the surplus portion 19 formed so as to be thinned from the main body portion 18 via the step s along the corner r of the step s, the peripheral edge of the injection molded body 5 and the preform molded body 3 are cut. Can be matched exactly with the perimeter of. According to such a method, in the production of a decorative molded body by in-mold molding, a portion where the injection molded body is exposed without leaving wrinkles on the preform molded body and without being covered by the preform molded body is generated. It is possible to stably mass-produce decorative molded products as final products that are difficult to make. In this embodiment, as an example, a cutting method with a cutter has been described. Examples of the cutter include an ultrasonic cutter and a water cutter. Further, instead of removing by cutting with a cutter, it may be removed by another method such as an end mill, a laser, or polishing.

1 Decorative sheet 2 Preform molded body before trimming 3 Preform molded body after trimming 3a Periphery 4 Unnecessary part of preform molded body 5 Injection molded body 8 Sprue runner 9, 10 Decorative molded body as an intermediate Female mold 11a Cavity part 12 Male mold 12a Core part 13 Mold 14 Injection part Main body 15 Molten resin 18 Main body part 19 Surplus part 20 Decorative molded body 40 Cutter blade c Cavity c1 Main body part forming part c2 Surplus part forming part PL mating surface r Corner s Step v Air vent w Wrinkles

Claims (7)

The process of preparing a preform molded body in which a decorative sheet is shaped into a three-dimensional shape, and
The preform molded body is arranged in the cavity portion of a mold having a male mold having a core portion and a female mold having a cavity portion that accommodates the core portion and forms a cavity when the mold is fastened. Process and
The female mold and the male mold are molded in a state where the preform molded body is housed in the cavity portion, and the formed cavity is filled with a molten resin and injection molded, whereby the preform is formed on the surface. It is provided with a process of molding a decorative molded body made of an injection molded body in which the molded body is integrated.
The cavity includes a main body portion forming portion that forms the main body portion of the decorative molded body, and a surplus portion forming portion that forms a surplus portion that is thinned from the peripheral edge of the main body portion via a step.
The preform molded body is arranged so that the peripheral edge thereof overlaps a part of the surplus portion in the decorative molded body.
A method for manufacturing a decorative molded product, further comprising a step of removing the excess portion. The method for manufacturing a decorative molded product according to claim 1, wherein the surplus portion is removed along the step. The method for manufacturing a decorative molded body according to claim 1 or 2, wherein the preform molded body does not abut on the tip surface of the surplus portion forming portion after the injection molding. The method for manufacturing a decorative molded body according to any one of claims 1 to 3, wherein the preform molded body is arranged so that its peripheral edge overlaps a part of the surplus portion forming portion before the injection molding. .. The decorative molding according to any one of claims 1 to 4, wherein the step between the main body portion and the surplus portion is 0.5 mm or more, and the thickness of the surplus portion is 0.4 to 1.5 mm. How to make a body. The method for manufacturing a decorative molded body according to any one of claims 1 to 5, wherein the preform molded body has a peripheral edge overlapping the surplus portion by 0.5 mm or more. The method for manufacturing a decorative molded product according to any one of claims 1 to 6, wherein the decorative sheet includes a fiber structure.

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