JP4026363B2 - Method for producing multilayer molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer molded body in which a skin material is bonded and integrated on a part of a substrate surface made of a thermoplastic resin.
[0002]
[Prior art]
Multi-layer molded products in which thermoplastic resin is molded by injection molding or compression molding, and a skin material is bonded and integrated on part of the substrate surface without using an adhesive, are widely used in the field of automotive interior materials. Recently, there is a demand for a product that has multiple skin material bonding parts as the needs diversify, and the skin material is bonded and integrated at two or more different positions on the substrate surface. Since these molded articles are heavy, weight reduction is demanded particularly in the field of automobile interior materials.
[0003]
In order to reduce the weight of such a molded article, it is generally known to foam the entire substrate (Japanese Patent Laid-Open No. 8-174585).
However, even though foaming the entire base material can be satisfactory in terms of weight reduction, it leads to a decrease in mechanical properties such as impact resistance and rigidity of the molded body. In the normally required skin material non-bonding part, the deterioration of mechanical properties due to foaming has been a big problem.
[0004]
[Problems to be solved by the invention]
For this reason, the inventor has integrated and integrated the respective skin materials at two or more different positions on a part of the surface of the base material made of thermoplastic resin without using an adhesive. As a result of studying the improved multilayer molded article, which is lightweight and yet has excellent impact resistance and rigidity at the non-skin-bonded portion, and a method for producing the same, the present invention has been achieved.
[0005]
[Means for Solving the Problems]
That First the present invention, and Table cladding material bonding unit the secondary Kesho or more different positions on each of the skin material is laminated integrally without using the adhesive on the substrate surface made of a thermoplastic resin, the skin In the multilayer molded object comprised from a material non-bonding part, the base material in an outer skin material bonding part provides the multilayer molded object characterized by being a foaming layer of foaming magnification 1.5-5 times . is there.
[0006]
In the second aspect of the present invention, the skin material to be bonded is supplied to a predetermined position corresponding to the skin material bonding portion of the mold surface of either one of the male and female molds composed of a pair of males and females, respectively. Supply molten foamable thermoplasticity between the skin material and the male or female mold surface, and after clamping, expand the mold cavity and foam, then the male and female of the skin material non-bonding part The present invention provides a method for producing the multilayer molded article comprising supplying and filling a non-foaming thermoplastic resin between both mold surfaces.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, although the multilayer molded object and its manufacturing method of this invention are demonstrated based on figures, it cannot be overemphasized that this description is an example of this invention and this invention is not limited to the description which concerns.
[0008]
【Example】
FIG. 1 is an example of the multilayer molded body (1) of the present invention, the left figure is a plan view seen from the skin material side, and the right figure is a cross-sectional view along AA ′. The body is a skin material in which the first skin material (4) and the second skin material (5) are bonded and integrated on the surface of a foamed base material (2) made of a foamed thermoplastic resin without using an adhesive. A structure composed of a bonding part and a non-foamed base material (3) (skin material non-bonding part) made of a non-foamed thermoplastic resin, and the foamed base material and the non-foamed base material are firmly joined; It has become.
[0009]
In this example, the first skin material (4) and the second skin material (5) are provided adjacent to each other, but they may be separated from each other, and the bonding position of the skin material is 2 It is not limited to three places, and three or more places may be provided at arbitrary different positions adjacent to or apart from each other.
[0010]
When these skin materials are provided adjacent to each other, it is necessary that the respective skin materials adjacent to each other are different from each other. The material may be the same.
[0011]
Here, the different skin material is not limited to the case where the material of the skin material itself is different, and means a skin material that can be distinguished from each other in terms of its appearance, feel, etc. even if the material itself is the same.
[0012]
In such a multilayer molded article (1), the base material of the skin material bonding portion is made of a foamed thermoplastic resin, the base material of the skin material non-bonding portion is made of a non-foamed thermoplastic resin, and each skin It is important that the material is bonded and integrated to the base material without using an adhesive, and the base material corresponding to the skin material bonding part and the skin material non-bonding part is separately molded, and the post-process However, considering the bonding strength between the base materials, the parts where the base materials are in contact with each other in the skin material bonding part and the non-skin material bonding part are fused and integrated. It is preferable.
[0013]
If the base material in a skin material bonding part is a foaming base material (foaming layer), the expansion ratio is not particularly limited, but it is usually 1.1 to 5 times, and the weight reduction of the multilayer molded product can be considered. If it is 1.5 to 5 times, it is still more preferable.
[0014]
A manufacturing method for obtaining such a foamed layer is not specified at all, but there are general methods such as a method of foaming by adding a foaming agent to a thermoplastic resin and a method of press-fitting a gas body into a molten thermoplastic resin. Applied.
[0015]
Examples of such foaming agents include inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate and ammonium carbonate, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, azodicarbonamide, azobisisobutyronitrile. Azo compounds such as benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, diphenylsulfone-3,9'-disulfonyl hydrazide, p-toluenesulfonyl semicarbazide, etc., and the amount used is the strength, density, etc. of the desired molded product Adjusted to take into account.
[0016]
In addition, carbon dioxide, nitrogen gas, carbon monoxide gas, etc. can be used as the gas body, and these may be used in a gaseous state or in a supercritical state, particularly in a supercritical state. By doing so, the gas body can be easily dissolved in the molten thermoplastic resin.
The amount of these gas bodies dissolved in the molten resin is adjusted in consideration of the strength and density of the target molded product.
[0017]
In the multilayer molded body of the present invention, the thermoplastic resin applied as the foamed and non-foamed base material is not particularly limited as long as it is a resin usually used in compression molding, injection molding, extrusion molding, etc. For example, polypropylene Polyethylene, acrylonitrile-styrene-butadiene block copolymer, polystyrene, nylon and other polyamides, polyvinyl chloride, polycarbonate, acrylic resin, styrene-butadiene block copolymer and other general thermoplastic resins, EPM, EPDM, etc. Examples thereof include thermoplastic elastomers, mixtures thereof, polymer alloys using these, and the like, and these are collectively referred to as thermoplastic resins in the present invention.
[0018]
These thermoplastic resins may contain fillers such as commonly used glass fibers and various inorganic or organic fillers as required. Of course, various commonly used pigments, lubricants, and antistatic agents. Various additives such as an agent and a stabilizer may be blended.
[0019]
Examples of the skin material applied to the present invention include woven fabrics and knitted fabrics such as moquettes and tricots, nonwoven fabrics such as needle punch carpets, metal foils, and sheets or films of thermoplastic resins.
These skin materials may be a laminated skin material having two or three or more layers in which foamed layers and backing layers are appropriately laminated as required, but those that can be heat-sealed with a thermoplastic resin, or skins. It is necessary that the thermoplastic resin in a molten state is impregnated on the back surface of the material and can be bonded to the base resin portion.
[0020]
As the foam layer of the skin material in this case, a polyolefin foam such as polypropylene or polyethylene, a polyvinyl chloride foam, a soft or semi-rigid polyurethane foam is preferably used.
[0021]
Although the manufacturing method of the multilayer molded body of the present invention is arbitrary, for example, the skin to be bonded at a predetermined position corresponding to the skin material bonding portion of the mold surface of either one of the male and female molds comprising a pair of male and female Each material is supplied, and then a melt-like foaming thermoplastic is supplied between each skin material and either male or female mold surface, and after mold clamping, the mold cavity is expanded and foamed, By supplying and filling non-foaming thermoplastic resin between the male and female mold surfaces of the skin material non-bonding part, the base material of the skin material bonding part is a foam layer, and the base of the skin material non-bonding part A multilayer molded body in which the material is a non-foamed layer can be produced.
[0022]
Hereinafter, an example of the manufacturing method will be described in detail.
FIG. 2 shows a state in which two kinds of skin materials (4, 5) are supplied between a male and female pair of male mold (6) and female mold (7) in an open state. In this example, two types of skin materials (4, 5) are adjacent to each other, but the respective skin materials may be supplied independently without being adjacent to each other.
[0023]
At this time, the first skin material (4) and the second skin material (5) are molded surfaces of the male mold (6) so as to correspond to the respective skin material bonding positions of the target molded body. In order to ensure the positioning of the skin material on the surface of the molded product, each skin material may be fixed by a clamping device provided in the male mold, or a female mold ( 7) It may be fixed to the molding surface on the side by vacuum suction.
Moreover, in the case where the skin material is bonded to the product outer peripheral portion, the end portion of the skin material may be fixed by a clamp frame provided on the outer peripheral portion of the male mold (6).
[0024]
These skin materials may be preheated in advance or may be preshaped according to the product shape.
[0025]
After supplying the skin material, the foamable thermoplastic resin (10) is supplied in a molten state between each skin material and one of the male and female mold surfaces.
[0026]
FIG. 3 shows a molten foamable thermoplastic resin (10) between the first skin material (4) and the second skin material (5) supplied between the molds and the molding surface of the male mold (6). ) Is supplied through a resin supply passage (8) provided in the mold.
[0027]
In this example, the end portions of the first skin material (4) and the second skin material (5) are in contact with each other, but the respective skin materials are independent of each other without being adjacent to each other. In this case, a resin supply port may be provided corresponding to each skin material bonding portion, and a foamable thermoplastic resin may be supplied from each resin supply port.
In this example, the same foaming thermoplastic resin is supplied to the foam base material forming portions corresponding to the first skin material (4) and the second skin material (5). When it is desired to provide different foamed layers corresponding to the above, it is only necessary to provide respective resin supply ports corresponding to the respective skin material bonding portions and supply different foamable thermoplastic resins from the respective resin supply ports.
[0028]
The cavity clearance between the male and female molds when supplying the foamable thermoplastic resin is appropriately determined according to the molding conditions such as the type of skin material used, the type of thermoplastic resin supplied and the melting temperature.
[0029]
As a method for supplying and filling the molten foamable thermoplastic resin (10), the supply is started from the state where both the male and female molds are closed so that the cavity clearance is equal to or less than the thickness of the molded product before foaming. While opening, the thickness of the molded product before foaming may be reached and the supply may be completed and injection filled, or the injection product may be filled while maintaining the thickness of the molded product before foaming, or cavity clearance The molten foamable thermoplastic resin (10) is supplied into the mold cavity with both the male and female molds opened so that the thickness is equal to or greater than the thickness of the molded product before foaming. Both molds may be clamped and filled so that the thickness of the molded product is as follows. (Fig. 4)
[0030]
At this time, the meaning of the thickness of the molded product before foaming in the cavity clearance is not necessarily strict, and may be slightly different.
Moreover, when performing mold clamping after completion of supply, it is preferable to start mold clamping immediately after completion of the supply of the molten foamable thermoplastic resin (10).
[0031]
In such a supply and filling method, in order to reduce damage to the skin material to be bonded to the base material, the molten foamable thermoplastic resin (2) was supplied into the mold cavity in an open state. After that, it is preferable to fill by mold clamping operation of both molds.
[0032]
When performing mold clamping after completion of the supply, it is preferable to start mold clamping immediately after completion of the supply of the molten foamable thermoplastic resin (10).
The clamping direction of the male and female dies may be the vertical direction or the horizontal direction.
In the example of this figure, the vertical direction is shown.
[0033]
By filling the molten foamable thermoplastic resin (10), the back surface of the skin material is brought into close contact with the molten foamable thermoplastic resin, and is firmly bonded and integrated by fusion or impregnation.
[0034]
When supplying the molten foamable thermoplastic resin or clamping the mold, the molten foamable thermoplastic resin (10) flows in the cavity during the supply or mold clamping and is made of a non-foamed thermoplastic resin. In order to prevent intrusion, the resin is located at the mold position corresponding to the boundary between the foam base material portion made of the foamable thermoplastic resin (10) and the non-foam base material portion made of the non-foamable thermoplastic resin (11). A stop frame (9) is provided, and the resin stop frame is protruded into the mold cavity by a device capable of moving back and forth, such as a spring or hydraulic pressure, so that the flow of the foamable thermoplastic resin (10) can be prevented. It is an effective means to block and prevent from flowing into the base material side made of non-foaming thermoplastic resin.
The resin retaining frame (9) may be protruded into the mold cavity from the start of supply of the molten foamable thermoplastic resin (10), or may be protruded at the start of mold clamping. .
[0035]
After the filling of the foamable thermoplastic resin (10) to the skin material bonding portion in the cavity was completed, the mold was opened so that the cavity clearance became the final product thickness, and the mold cavity was enlarged and supplied. A foamable thermoplastic resin is foamed. (FIG. 5).
[0036]
The mold cavity expansion timing may be started immediately after completion of filling, but after cooling is completed, the skin layer is formed on the surface, particularly the resin surface in contact with the mold forming surface. It is desirable to enlarge the mold cavity.
The cooling time varies depending on various conditions such as mold temperature, type of foaming thermoplastic resin and melting temperature, but is usually in the range of 0.1 to 5 seconds.
[0037]
Expansion of the mold cavity is continued until the mold cavity clearance reaches the final molded product thickness, and after expanding the foamable thermoplastic resin in the cavity, the expansion of the mold cavity is stopped.
Thus, it is preferable to cool for a fixed time after foaming the base resin part. This cooling time varies depending on various conditions such as mold temperature, type of foaming thermoplastic resin and melting temperature, but is usually in the range of 0.1 to 20 seconds.
[0038]
After foaming the base resin part for skin material bonding in this way, while maintaining the cavity clearance in this state, in the mold cavity between the male and female molds corresponding to the skin material non-bonded part, The non-foaming thermoplastic resin (11) is supplied and filled in the cavity.
[0039]
FIG. 6 shows a melted non-foaming thermoplastic in a mold cavity via a resin supply path (8) for feeding a non-foaming thermoplastic resin (11) provided in the male mold (6). The place where resin (11) is supplied is shown.
[0040]
When the resin retaining frame (9) is used, the resin retaining frame protruded into the cavity in the previous step is from the start of supply of the molten non-foaming thermoplastic resin (11). It is preferable to return to the mold at any stage until the supply is completed, preferably at the start of supply.
[0041]
After that, by cooling and solidifying and opening both the male and female molds, the base material of the skin material bonding portion is formed from a foamed resin, and the base material of the skin material non-bonding portion is formed from a non-foamed resin. And the molded product with which these base materials were joined firmly is taken out.
[0042]
【The invention's effect】
In the multilayer molded body of the present invention, the base material of the skin material bonding part is a foamed layer and the base material of the skin material non-bonding part is a non-foamed layer. Further, the multilayer molded body can be easily produced according to the method of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a multilayer molded article of the present invention, in which the left figure is a plan view seen from the skin material side, and the right figure is a sectional view thereof.
FIG. 2 shows the production process of the multilayer molded article of the present invention with a schematic cross-sectional view of the mold. FIG. 3 shows the production process of the multilayer molded article of the present invention with a schematic sectional view of the mold. Fig. 4 shows the production process of the multilayer molded product of the present invention in a schematic sectional view of the mold. Fig. 5 shows the production process of the multilayer molded product of the present invention in a schematic sectional view of the mold. FIG. 6 is a schematic sectional view of a mold showing the production process of the multilayer molded article of the present invention.
1: Multilayer molded body 2: Foam base material 3: Non-foam base material 4: First skin material 5: Second skin material 6: Male mold 7: Female mold 8: Resin supply passage 9: Resin retaining frame 10: Foaming thermoplastic resin 11: Non-foaming thermoplastic resin

Claims (4)

  A plurality of skin material bonding parts in which each skin material is bonded and integrated without using an adhesive at two or more different positions on the surface of the base material made of a thermoplastic resin, and the skin material is bonded. It is a method for producing a multilayer molded body composed of a non-sealable skin material part,
  The skin material is respectively supplied to positions corresponding to the skin material bonding portion of the multilayer molded body of the mold surface of either one of the male and female molds comprising a pair of male and female,
  Supply a molten foamable thermoplastic resin between each skin material and one of the male and female mold surfaces, and after mold clamping, expand the mold cavity and foam, ,
  A method for producing a multilayer molded body, comprising supplying and filling a non-foaming thermoplastic resin into a mold cavity corresponding to the non-bonding portion of the skin material.   The method for producing a multilayer molded article according to claim 1, further comprising a step of cooling for a predetermined time after supplying the foamable thermoplastic resin and performing mold clamping.   The method for producing a multilayer molded body according to claim 1, further comprising a step of cooling for a predetermined time after the mold cavity is expanded and foamed.   A resin retaining frame capable of advancing and retreating is provided at a position corresponding to a boundary portion between the skin material bonding portion and the skin material non-bonding portion, and the resin retaining frame is used as the non-foaming thermoplastic resin. The method for producing a multilayer molded article according to any one of claims 1 to 3, wherein the protrusion is made to protrude when the is supplied.

Images