JP4197980B2 - Method for producing multilayer molded product - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a multilayer molded article comprising a base material made of a thermoplastic resin and a skin material bonded and integrated on at least a part of the surface thereof, and in particular, two or more skin materials have no gap between each other. The present invention relates to a method for producing a multilayer molded product that is laminated and integrated with a base material in a juxtaposed state.
[0002]
[Prior art]
Conventionally, a multilayer molded article formed by bonding a surface material such as a synthetic resin sheet, a woven fabric or a non-woven fabric to a part of the surface of a base material made of a thermoplastic resin has an economical efficiency, a light weight and a good imparting property. From the viewpoint of shape and the like, it is widely used in automobile interior parts (for example, door trims and instrument panels), interior / exterior parts of home appliances, and other fields.
[0003]
Such a multilayer molded article, in which two kinds of skin materials are bonded and integrated with a base material in a state where they are juxtaposed with each other with no gap, is conventionally a method as disclosed in, for example, Patent Document 1 below Manufactured by. In this manufacturing method, as shown in FIG. 8A, the edges of the two types of skin materials 1 and 2 are overlapped with each other, and the overlapped portions are clamped with a clamp member 3 to form dies 4 and 5. After that, as shown in FIG. 8B, the main resin supply gates 6 and 7 provided on the back surfaces of the respective skin materials 1 and 2 serve as a base material. A molten thermoplastic resin (molten resin) 8 is supplied into the cavities between the dies 4 and 5 to produce a multilayer molded product. Here, the “main resin supply gate” means a gate that can supply a large part of the amount of resin necessary for manufacturing the substrate, for example, 60% or more, and an auxiliary resin that compensates for the shortage. It does not include the supply gate. Hereinafter, when simply referred to as “resin supply gate”, “main resin supply gate” is indicated.
[0004]
[Patent Document 1]
JP-A-2-175111
[Problems to be solved by the invention]
As shown in FIGS. 8 (a) and 8 (b), the conventional method for manufacturing a multilayer molded article as described above is such that the resin supply gates 6 and 7 are located at positions facing the portions where the skin materials 1 and 2 are disposed. If formed, a multilayer molded article can be suitably produced.
[0006]
However, depending on the shape and position of the skin material, the resin supply gate may not be provided at a position facing the skin material placement site. For example, as in a multilayer molded product (door trim which is an automobile interior part) 10 shown in FIG. 9, at least one skin material 12 is elongated and the position of the bonding portion is a position applied to the edge of the base material 14. In some cases, it is difficult to form the resin supply gate at a position facing the skin material arrangement site. When the molten resin is supplied from the resin supply gate located at a position away from the skin material arrangement site, the edge of the skin material is pushed and moved by the flow of the molten resin, or the design surface of the skin material ( The molten resin wraps around the (surface) side, and the appearance of the product is impaired. Of course, it is possible to form the resin supply gate so as to face the skin material arrangement portion, but the cost for manufacturing a mold having such a gate becomes enormous.
[0007]
Moreover, since it is necessary to set a clamp member in a metal mold | die, the structure of a metal mold | die is complicated, and there also exists a problem that cost becomes high.
[0008]
Therefore, the present invention produces a multilayer molded product in which at least two types (two sheets) of skin material are bonded and integrated on the surface of the base material, regardless of the shape and position of the skin material, at a low cost. It aims at providing the manufacturing method which can do.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing a multilayer molded article according to the present invention includes a first mold having a main resin supply gate for supplying a molten thermoplastic resin, and a first mold. A second mold that is openable and closable and that forms a cavity with the first mold when closed, and the first and second molds in an open state A step of arranging two or more skin materials at predetermined positions between the first mold and the second mold so that the adjacent edges overlap each other, and the resin between the first mold and the second mold Supplying molten resin from a supply gate and filling the molten resin. Furthermore, in the method according to the present invention, when two or more skin materials are arranged at the predetermined position, one of the two or more skin materials is positioned so as to face the resin supply gate. In addition, the overlapping portion between the adjacent skin materials is such that the skin material farther from the resin supply gate is located on the second mold side than the skin material near the resin supply gate. It is said. The mold can be clamped during or after the molten resin is supplied.
[0010]
When a multilayer molded article is manufactured by such a method, the molten resin from the resin supply gate spreads around from the back surface of the first skin material facing the gate, but the adjacent second skin material Since the overlapping portion is on the design surface side of the first skin material, that is, the second mold side, the molten resin pushes the edge of the second skin material, or the molten resin on the design surface side of the skin material Can be prevented from going around.
[0011]
Further, it is possible to arrange two or more skin materials at the predetermined positions so that the edges of the adjacent skin materials are in contact with each other without overlapping (that is, in a butt relationship) when the mold clamping is completed. Above, it is preferable.
[0012]
Furthermore, the first mold is provided with a recess, and the second mold is provided with a ridge at a position facing the recess, so that the edge between adjacent skin materials in the multilayer molded product after the manufacture is completed. It is preferable to arrange two or more skin materials at the predetermined positions so that the positions correspond to the ridges. This is because it is possible to obtain a molded product with more favorable positioning and appearance of the edge portion of the skin material.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, this embodiment is as shown in FIG. 9 demonstrated previously, the base material 14, the skin material 16 bonded by the approximate center part of the surface of the base material 14, and a part of edge of the skin material 16 In particular, the present invention relates to a method of manufacturing a multilayer molded article 10 that includes the skin material 12 that is juxtaposed with each other without gaps and that covers the edge of the end face of the base material 14.
[0014]
First, a molding apparatus used for manufacturing the multilayer molded article 10 of FIG. 9 according to the method of the present invention will be described with reference to FIGS. As shown in the figure, this molding apparatus 20 is a general device used when a single skin material is bonded to a base material, and the like. A first mold 24 that is a male mold supported on the upper surface, a mold support plate 28 that is disposed above the mold support plate 22 and is moved up and down by a driving device 26, and a lower surface of the mold support plate 28. And a second mold 30 which is a female mold supported by the first and second molds.
[0015]
The pair of upper and lower molds 24 and 30 respectively have cavity surfaces 32 and 34 that correspond to the desired shape of the multilayer molded article 10 and face each other. The cavity surfaces 32 and 34 form cavities that generally match the outer shape of the desired multilayer molded article 10 when the upper and lower molds 24 and 30 are closed. The material of the molds 24 and 30 is not particularly limited, and is appropriately selected from various metal materials, resins, ceramics, and the like depending on a required shape, surface state, and molding conditions.
[0016]
The cavity surface 32 of the lower mold 24 is provided with a main resin supply gate 36 for supplying the molten resin into the cavity. The resin supply gate 36 is a resin supply passage 38 formed in the mold 24. Communicated with. The resin supply passage 38 is connected to an injection nozzle of an injection device (not shown) that can melt the thermoplastic resin and inject a desired amount. The position of the resin supply gate 36 is a position corresponding to a portion to which at least one skin material (skin material 16 in this embodiment) is bonded, in other words, when molten resin is supplied from the resin supply gate 36. Further, the molten resin is supplied to the back surface side of the skin material 16. In addition, the resin supply gate 36 is preferably provided at a position corresponding to a portion where the skin material having the largest projected area is pasted, but the product shape and the positional relationship for pasting the skin material and the skin material are pasted. Depending on the proportion of the portion that is not, etc., it may be arranged on the side of the skin material having a small transparent area, and in this embodiment, it is provided for the skin material 16 having a small transparent area. The number of resin supply gates 36 is appropriately changed depending on the shape and size of the multilayer molded product 10 to be manufactured. If the molten resin cannot be distributed in the cavity with only the main resin supply gate 36, an auxiliary resin supply gate (not shown) may be provided at other parts of the cavity surface 32 as appropriate. Good.
[0017]
Further, a clamp device 40 for clamping the skin material 12 is disposed outside the lower mold 24. The clamp device 40 includes a clamp frame 42. As understood from the two-dot chain line in FIG. 2, the clamp frame 42 protrudes from the cavity surfaces 32 and 34 of the molds 24 and 30 when the skin material 12 is supplied between the molds 24 and 30. Is sandwiched between the lower surface of the outer peripheral portion of the upper mold 30. In the illustrated embodiment, the clamp frame 42 has a continuous U-shape as shown in FIG. 2, but may have other forms, for example, a plurality of divided forms. The clamp frame 42 can be moved up and down by a drive device 44 such as an air cylinder.
[0018]
Next, a method for manufacturing the multilayer molded article 10 of FIG. 9 using the above-described molding apparatus 20 will be described with reference to FIGS.
[0019]
First, a thermoplastic resin to be the base material 14 of the multilayer molded article 10 and two skin materials 12 and 16 are prepared. In the present embodiment, one skin material 16 is disposed at a substantially central portion of the surface of the base material 14, and the other skin material 12 is of a type different from the skin material 16, and is an edge of the surface of the base material 14. It is arranged in the part concerning.
[0020]
The thermoplastic resin is put into an injection device (not shown) and is in a molten state in advance.
[0021]
As shown in FIG. 3A, the skin material is supplied between the molds 24 and 30 in an open state, and is arranged side by side at a predetermined position on the cavity surface 32 of the lower mold 24. In this state, the resin supply gate 36 is located on the back side of the skin material 16. The skin material 16 may simply be placed on the mold 24, but a part of the outer peripheral portion may be fixed by a clamp piece or a pin (not shown) provided on the mold 24. Further, as shown by a two-dot chain line in FIG. 2, a part of the outer peripheral portion of the skin material 12 protrudes from the mold 24, and this portion is placed on the clamp frame 42 and appropriate fixing means such as a pin (not shown). ) To position and fix to the clamp frame 42. When the skin materials 12 and 16 are arranged on the cavity surface 32 of the mold 24 and the skin material 12 is positioned on the clamp frame 42, the edges of the skin material 12 and the skin material 16 are partially overlapped with each other. In the portion 46, the skin material 12 on the side far from the resin supply gate 36 is placed on the skin material 16 on the side close to the resin supply gate 36.
[0022]
The degree of overlapping of the skin materials 12 and 16 is preferably set to such an extent that the edges of the skin materials 12 and 16 do not separate at the mold clamping stage described later. It is more preferable that the edges are in contact with each other without overlapping each other.
[0023]
Next, the drive device 26 is controlled to move the upper mold support board 28 and the mold 30 downward, and the outer peripheral portion of the skin material 12 between the lower surface of the outer peripheral portion of the upper mold 30 and the clamp frame 42. Pinch. Then, the drive device 44 of the clamp device 40 is controlled to lower the clamp frame 42 together with the mold 30 while maintaining the state in which the skin material 12 is clamped.
[0024]
When the mold 30 is lowered and stopped at a predetermined position in this way, a cavite 48 having a predetermined size is formed between the molds 24 and 30. If the cavity 48 is formed between the molds 24 and 30, when the molten resin 50 is injected from the injection device, the molten resin 50 passes from the resin supply passage 38 of the mold 24 into the cavity 48 through the resin supply gate 36. Is supplied ((b) of FIG. 3). At this time, the molten resin 50 supplied from the resin supply gate 36 first presses the skin material 16 against the cavity surface 34 of the mold 30, and then gradually expands the space in the cavity 48 in the horizontal direction. It flows to. As shown in FIG. 4, the skin material 12 covers the edge of the skin material 12 because the skin material 12 is on the upper side of the skin material 16 in the overlapping portion 46 of the skin materials 12 and 16. And the edge of the skin material 16 is pressed by the edge of the skin material 12 by the flow of the molten resin 50, and both adhere closely. As a result, the molten resin 50 does not push the edge of the skin material 12, and a gap is formed between the skin materials 12 and 16, or the molten resin 50 is on the design side (side facing the mold 30). Never get in. Note that the cavity clearance between the molds 24 and 30 when the molten resin 50 is supplied is appropriately determined depending on the type, product shape, dimensions, and the like of the skin materials 12 and 16 to be used.
[0025]
Next, the mold 30 is further lowered to perform mold clamping, and the molten resin 50 filled in the cavity 48 is cooled and solidified ((c) in FIG. 3). The timing of mold clamping may be either during the supply of the molten resin 50 or after the supply is completed. However, when the mold clamping is performed after the supply is completed, the mold clamping is started immediately after the supply of the molten resin 50 is completed. Is preferred. At the time of clamping, since the sandwiched portion of the skin material 12 between the clamp frame 42 and the mold 30 moves downward with respect to the mold 24, an appropriate tension is applied to the skin material 12. In addition, by controlling the amount of movement, it is possible to reduce the overlapping portion between the skin material 12 and the skin material 16, and more preferably to arrange them in a butted state without overlapping.
[0026]
When the predetermined cooling / solidification time has elapsed, the mold support board 28 and the mold 30 are raised, and the base material 14 formed by solidifying the molten resin 50 is bonded to the skin materials 12 and 16. Take out the multilayer molded product. Thereafter, processing such as excision of the protruding portion of the skin material 12 and winding on the back surface of the product is performed, and the multilayer molded product 10 as a product shown in FIG. 9 is completed. As described above, since the molten resin does not flow into the design surface side of the skin materials 12 and 16 and the positional displacement of the skin materials 12 and 16 does not occur, the appearance of the product becomes extremely good.
[0027]
In addition, as a thermoplastic resin, resin normally used by compression molding, injection molding, extrusion molding, etc. can be applied as it is. For example, general thermoplastic resins such as polypropylene, polyethylene, acrylonitrile-styrene-butadiene block copolymers, polyamides such as polystyrene and nylon, polyvinyl chloride, polycarbonate, acrylic resins, styrene-butadiene block copolymers, EPM and EPDM Examples thereof include thermoplastic elastomers such as these, mixtures thereof, and polymer alloys using these, and these may be non-foaming or foaming.
[0028]
Further, these thermoplastic resins may contain fillers such as glass fibers that are usually used as required, various inorganic or organic fillers, and of course various pigments, lubricants that are usually used, Additives such as antistatic agents and stabilizers may be blended.
[0029]
As the skin material, any material that does not melt even when in contact with a thermoplastic resin in a molten state and can be heat-sealed to the thermoplastic resin, for example, a woven or knitted fabric such as a moquette or to limit, a needle Nonwoven fabrics such as punched carpets, metal foils, thermoplastic resins and thermoplastic elastomer sheets or films can be appropriately selected according to the thermoplastic resin of the substrate.
[0030]
These skin materials may be laminated skin materials having two layers or three or more layers in which foam layers and backing layers are appropriately laminated as required, and skin materials in which foam layers are laminated are particularly preferably applied. These laminated skin materials can be bonded to the base material thermoplastic resin, or the surface skin material can be impregnated with molten thermoplastic resin to adhere to the base material thermoplastic resin. It is necessary to be something.
[0031]
As the foam layer in this case, polyolefin-based foams such as polypropylene and polyethylene, polypinyl chloride foam, and soft or semi-rigid polyurethane foam can be used.
[0032]
As the backing layer, a nonwoven fabric or a synthetic resin sheet or film can be used. As the fibers constituting the nonwoven fabric, natural fibers such as cotton, wool, silk and hemp, or synthetic resins such as polyamide, polyester, and nylon can be used. What was made into the nonwoven fabric is used. Examples thereof include nonwoven fabrics such as a needle punch type, a thermal bond type, a spun bond type, a melt blow type and a spun lace type. Examples of the sheet or film made of a synthetic resin include a thermoplastic resin such as polypropylene and polybutylene, and a sheet or film of a polyolefin-based thermoplastic elastomer, and a material that is fusible with the base thermoplastic resin is used.
[0033]
As mentioned above, although preferred embodiment of this invention was described in detail, it cannot be overemphasized that this invention is not limited to the said embodiment.
[0034]
For example, a foamable thermoplastic resin can be used for the base material 14. In order to foam the base material 14, the skin material 12, 16 is positioned and the cavity 48 is formed between the dies 24, 30 in the same manner as the above-described procedure of FIGS. Thereafter, the molten resin 50 containing the foaming material is supplied from the resin supply gate 36 to perform mold clamping. First, primary cooling is performed in the mold clamping state shown in FIG. 3C, and a skin layer is formed on the molten resin 50 in contact with the cavity surface 34 of the mold 30. The primary cooling time at this time is usually about 0.1 to 5 seconds, although it varies depending on various conditions such as mold temperature, molten resin temperature and characteristics. When primary cooling is completed for a predetermined time, as shown in FIG. 3D, when the mold 30 is moved upward and the cavity 48 is enlarged, it is trapped in the unsolidified portion of the supplied molten resin 50. The foaming gas generated by the decomposition of the foaming agent that has been expanded expands and increases the thickness while forming a foamed layer in the thickness direction of the molded product. When the cavity clearance reaches the product thickness after foaming, the cavity expanding operation, that is, the rise of the mold 30 is stopped, and this state is maintained and the molten resin 50 is cooled and solidified.
[0035]
As the foaming agent used in this method, a known chemical foaming agent used when producing a foam of a thermoplastic resin as a base can be used. Specifically, inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate and ammonium carbonate, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, azodicarbonamide, azo such as azopisisobutyronitrile, etc. A blowing agent such as a compound, a sulfonyl hydrazide such as benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, or p-toluenesulfonyl semicarbazide can be used. It is a preferred embodiment to add salicylic acid, urea and a foaming aid containing these as required. Of course, the type of foaming agent is selected in consideration of the melting temperature of the thermoplastic resin to be used, the target foaming ratio, and the like. The amount added is adjusted in consideration of the strength, density and the like of the target molded product, but is generally 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin. Further, in addition to the chemical foaming agent, liquid or gaseous carbon dioxide and / or nitrogen or the like may be directly injected into the molten resin for foaming.
[0036]
Moreover, the metal mold | die used for this invention is not restricted to what is shown in FIGS. 1-3, As shown in FIG. 5, it is the recessed part 56 in the position corresponding to the metal mold | die 54 which has the protrusion 52, and the protrusion 52. As shown in FIG. Alternatively, a mold 58 provided with may be used. In this case, the protrusion 52 is provided at a position corresponding to a boundary portion between the skin materials 12 and 16 in the multilayer molded article 10 after the manufacture is completed, that is, a so-called edge portion 18 (see FIG. 9). In the configuration shown in FIG. 5, the same or corresponding parts as those in the configuration shown in FIG.
[0037]
When the multilayer molded article 10 of FIG. 9 is manufactured using the molds 54 and 58, the skin materials 12 and 16 are arranged at predetermined positions between the molds 54 and 58 in the same manner as described with reference to FIG. Thereafter, when the mold 54 is lowered, the overlapping portion between the skin materials 12 and 16 is in a state as shown in FIG. In this state, the protrusion 52 makes the direction of the flow of the molten resin 50 downward, and then flows outward along the inner surface of the concave portion 56, so that the molten resin 50 is further on the design surface side of the skin materials 12 and 16. It will not enter (on the side facing the mold 54).
[0038]
When the molten resin 50 is supplied, it is preferable to set the position so that the cavity clearance between the molds 54 and 58 is smaller than the height of the protrusion 52. In other words, it is preferable that the tip of the ridge 52 is positioned so as to slightly enter the recess 56. If the molten resin is supplied in a state where the cavity clearance is larger than the height of the protrusion 52, the protrusion 52 does not function as a flow deflection function or a weir of the molten resin 50, and the design of the skin materials 12, 16 This is because the molten resin 50 may enter the surface side and cause a defective appearance of the product.
[0039]
The mold clamping is performed during the supply of the molten resin 50 or after the completion of the supply, and the multilayer molded article 10 is taken out from the molds 54 and 58 after cooling and solidification is the same as described above.
[0040]
Furthermore, in the above embodiment, two types (two sheets) of skin materials 12 and 16 are used, but three types (three sheets) or more of skin materials are juxtaposed with each other without any gaps and bonded and integrated with the base material. Even in this case, the present invention is applicable. That is, the present invention is simply arranged by stacking a plurality of skin materials stepwise, and flowing molten resin from the skin material closest to the resin supply gate, so that the molten resin can be applied to the design surface side of the skin material. In order to prevent wraparound and displacement of the skin material, for example, three or more skin materials 100, 102, 104, and 106 are arranged in a manner as shown in FIGS. The position of the main resin supply gate 36 for supplying 50 may be determined.
[0041]
Further, in the above embodiment, the molding apparatus 20 uses a so-called vertical type in which the clamping direction is the vertical direction. However, in the present invention, the clamping direction is the horizontal direction, that is, at least one of the molds is the horizontal direction. It is also applicable to a horizontal molding apparatus that is movable.
[0042]
Further, in the above embodiment, the skin material is not previously processed, but the skin material may be preheated or preshaped before being supplied between the molds. In particular, when preliminary shaping is performed, there is an advantage that accurate positioning can be performed.
[0043]
【The invention's effect】
As described above, according to the production method of the present invention, it is possible to efficiently produce a multilayer molded product having a good positioning property and appearance of the skin material. Moreover, since the position of the resin supply gate may be a general position, there is an effect that the cost for manufacturing the mold can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a molding apparatus that can be used in a method for producing a multilayer molded article according to the present invention.
FIG. 2 is a schematic arrow view along the line II-II in FIG. 1;
FIGS. 3A to 3D are schematic explanatory views showing a method for producing a multilayer molded article according to the present invention in stages, and FIG. 3D is a case of producing a multilayer molded article having a foamable substrate. FIG.
FIG. 4 is an enlarged view of a mold showing a flow state of a molten resin.
FIG. 5 is a schematic view showing another example of a molding apparatus that can be used in the method for producing a multilayer molded article according to the present invention.
6 is a view similar to FIG. 4, showing a method for producing a multilayer molded article using the molding apparatus of FIG. 5;
FIGS. 7A and 7B are schematic explanatory views showing an application example of the present invention when there are three or more skin materials. FIGS.
FIG. 8 is a schematic explanatory view showing a conventional method for producing a multilayer molded article.
FIG. 9 is a schematic view showing an example of a multilayer molded article produced by the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Multilayer molded article, 12 ... Skin material, 14 ... Base material, 16 ... Skin material, 18 ... Margin part, 20 ... Molding apparatus, 24, 58 ... 1st metal mold | die, 30, 54 ... 2nd metal Mold, 36 ... main resin supply gate, 40 ... clamping device, 48 ... cavity, 50 ... molten resin, 52 ... ridge, 56 ... recess.

Claims (4)

A method for producing a multilayer molded article comprising a base material made of a thermoplastic resin, and two or more skin materials laminated and integrated on at least a part of the surface of the base material and juxtaposed with each other without a gap. ,
A first mold having a main resin supply gate for supplying a thermoplastic resin in a molten state, and can be opened and closed with respect to the first mold; and when the first mold is closed, Providing a second mold for forming a cavity therebetween;
Disposing the two or more skin materials at predetermined positions between the first mold and the second mold in an open state so that adjacent edges overlap each other;
Supplying a molten thermoplastic resin from the main resin supply gate by narrowing an interval between the first mold and the second mold, and filling the molten resin.
Of the two or more skin materials, one skin material is located at a position facing the main resin supply gate, and the adjacent portion of the skin materials is close to the main resin supply gate The two or more skin materials are arranged at the predetermined position so that the skin material on the side farther from the main resin supply gate is located on the second mold side than the skin material. A method for producing a multilayer molded article. The method for producing a multilayer molded article according to claim 1, wherein a molten thermoplastic resin is supplied and the mold is clamped. The two or more skin materials are arranged at the predetermined position so that the edges of the skin materials adjacent to each other are in contact with each other at the time of completion of mold clamping. A method for producing a multilayer molded article. A recess is provided in the first mold, and a protrusion is provided at a position facing the recess in the second mold.
The two or more skin materials are arranged at the predetermined position so that an edge portion between adjacent skin materials in a multilayer molded product after the manufacture is completed is a position corresponding to the protrusion. Item 4. The method for producing a multilayer molded article according to any one of Items 1 to 3.

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