JPS60135221A - Preparation of resin molded product - Google Patents

Abstract

PURPOSE:To obtain a resin molded product having smoothness equal to that of a steel panel without generating a shrink-mark caused by the volumetric shrinkage in the surface side of a projection, in preparing a resin molded product having a projection provided to the back surface thereof, by integrally molding the back surface layer having the projection of siad molded product after the surface layer thereof is molded. CONSTITUTION:Both molds 2, 4 are opened after the elapse of 30sec from the completion of the thermal press molding of a surface layer 1a, and a resin sheet 1'' is placed on the surface layer 1a while hydraulic cylinders 11, 12 are operated to penetrate slide cores 8, 8 from the molding surface 4a of the back surface mold 4 and both molds 2, 4 are again closed, while molding spaces 7, 7 for forming the projections 6 of a resin molded product 1 are constituted, to integrally form the back surface layer 1b and front surface layer 1a of the resin molded product 1 in the gap constituted between the surface layer 1a and the molding surface 4a of the back surface mold 4. That is, in preparing the resin molded product 1 having the protections provided to the back surface thereof, the back surface layer 1b having the projections is formed after the surface layer 1a is formed and, therefore, no shrink-mark is generated in the surface side of each projection and a smooth surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF CM INDUSTRIAL APPLICATION The present invention relates to a method for manufacturing resin molded products used for automobile exterior panels and the like.

(Prior Art) A resin molded product used as an automobile outer panel or the like is generally provided with a protrusion on the back surface in order to obtain durability. However, such NIJI
In W molded products, sink marks occur on the front surface side of the back protrusion due to volumetric shrinkage after molding, and there is a problem in that smoothness comparable to that of steel panels, which is required for exterior panels, cannot be obtained. As a method of preventing this sink, various methods,
For example, the composition and molding conditions of in-mold coating and dung bound have been studied, but it has not been possible to completely prevent sink marks. In addition, Tokukai Showa S Otsu-13q9'12
The publication describes that after resin is injected into the cavity of a split mold to form a primary molded product, the mold is slightly opened and another resin is injected into the gap to create a multilayer resin molded product in a two-step process. A method for obtaining a WB having a protrusion on the back surface is disclosed.
IIW fK type products are not mentioned at all.

(Object of the Invention) The present invention has been made in view of the above points, and its object is to integrally form a smooth surface layer and a back layer that extends over the protrusions by two-step molding, thereby forming a film. The purpose is to prevent sink marks from forming on the surface side.

(Structure of the Invention) In manufacturing a resin molded product having a protrusion on the back side, the method of the present invention uses a surface mold having a molding surface that forms the surface of the at N molded product, and a molded product on the PM side. A back mold having a molding surface that forms a back surface, and a slide core that is movably provided on the back mold and has a molding surface that can form the molding space of the protrusion are prepared, and first, the slide core is The surface layer of the resin molded product is formed in the cavity formed between the molding surface of the front mold and the molding surface of the back mold by aligning the molding surface with the molding surface of the back mold, and then both molds are At the same time, the slide core is recessed from the molding surface of the back mold to form a molding space for the protrusion, and in the gap formed between the surface layer attached to the front mold and the molding surface of the back mold. The back layer of the molded product was formed integrally with the surface layer, and then both molds were completely opened, and the slide core was made to protrude and the mold was attached to the back mold.
The feature is that the fat molded product can be taken out.

(Example) Hereinafter, an example of the method of the present invention will be specifically described with reference to the accompanying drawings.

7 to 6 show a molding process in a method for manufacturing a resin molded article by hot press molding, which is a first embodiment of the present invention.

The molding apparatus used in this first embodiment is capable of producing the desired 11 B
'? A surface mold 2 having a molding surface 2φ that forms the surface of a molded product (see figure 6), a heating plate 3 that heats the surface mold, and a molding surface that forms the back surface of the resin molded product L. 11
a back mold t provided with a heating plate S for heating the back mold t;
is movably provided on the front 1d back mold t, and the NWi molded product/back protrusion 6. A slide core 1 having a molding surface fΦ+11z that can form a molding space 717 (see Figure 1). It is equipped with Ir.

Previous ``d front type 2 and back side type q are templates 9I10 respectively.
is fixed on the heating plate 3.5 by.

Each of the slide cores r is a hydraulic cylinder.

#41 so that it can be moved vertically by /2
has been completed.

The hydraulic cylinder /l is for directly moving the slide core, and the hydraulic cylinder 12 is for moving the slide core together with the hydraulic cylinder /l.

Note that the code /3. /≠ indicates a mounting plate, /s indicates a spacer block, and /4 indicates a land block.

Next, the manufacturing process of the N resin molded product of this example will be described in detail.

In advance, a resin sheet l made of reinforcing fiber-incorporated thermosetting resin is placed on the molding surface 2C of the front mold 2 (see Fig. 1), and the slide core r and the molding surfaces Irg and Ir- are placed on the molding surface 2C of the back mold. The molded surface of t≠C almost coincides with both the front and back surfaces m2,
While heating lI with the heating plates 3 and 5, both molds λ and lI are closed, and the molding surface Ja of the front mold 2 and the molding surface lIa of the back m<<
The surface layer /a of the molded product l is formed in the cavity formed between the molded product l (see Fig. 2). Next, both types 2.11
are separated from each other, leaving the surface layer /e on the surface mold λ side. At this time, the hydraulic cylinder /l is activated, and both molds 2. When separating μ, the surface layer /φ is pressed against the surface mold 2 (see FIG. 3). In addition, in order to leave the surface layer /e on the surface mold 2 side, air may be introduced between the back mold l and the surface layer l'C,
In addition, the surface layer /e has a shape that can be easily formed into an M shape from the back surface 119.
In this case, this step is not necessary. Both molds are completed 30 seconds after hot press molding of 7g of surface layer! , lI open, surface layer 1
A resin sheet l similar to the above is placed on top of the mold 6, and the hydraulic cylinders // and 12 are operated to sink the slide cores r and r into the molding surface 11g of the back mold l, forming a tIITa molded product.
While configuring the molding space 7.7 of the protrusion 6°t (see Fig.
Vii in the gap formed between the molding surface 11a of Hiro.
The back layer /b of the resin molded product is formed integrally with the surface layer /C (see Figure 3). At this time, both types 2. If the back layer/b is hot-press molded within 7 minutes after opening, the surface layer/c&
is cured by 7~g, and the surface is activated, so the back layer/
The bondability with b is improved. Thereafter, both molds 2 and 11 are completely opened, hydraulic cylinders // and /2 are operated to cause gg to protrude from the slide core, and the resin molded product / attached to the back mold ψ is taken out (see FIG. 6). That is, at this time, the slide core acts as an ejector for taking out the Ml IIW molded product.

As mentioned above, in manufacturing the resin molded product/ having the protrusions A and B on the back surface, after forming the surface layer A, the protrusions B and
Since the back layer /b having the protrusions 6. This eliminates the occurrence of sink marks on the surface side of B and provides a smooth surface.

1g7 to 9 show the molding process of the M2 embodiment of the present invention. The molding device in this case includes a front mold 2, a back mold t, and a slide core.

G... is growling. Code/7. /f is the M fatty inlet. First, align Φ+f tz... with the molding surface of the slide cores g, i... almost with the molding surface ≠ α of the back mold, close both molds 2.11, and pour the thermoplastic from the injection path /7. Forming the surface layer/c of the resin molded product by injecting the resin (see Figure 7). Then, 1iIII type 2. At the same time, the hydraulic cylinder // is operated to immerse the slide cores g, g, etc. from the molding surface lIΦ of the back mold t, and thermoplastic resin is injected into both from the injection path /I to form the surface layer. /
A back layer /b is formed integrally with c&, and a resin molded product l having protrusions B, B, etc. is formed (see the figure below). after that,
After fully opening both m2 and 'iZ, the hydraulic cylinder/
/ to protrude the slide core g9g...
Take out the resin molded product attached to the back mold t (w, see Figure 9).

Note that the second embodiment can also be applied to two-component reaction molding.

(Effects of the Invention) As described above, according to the method of the present invention, when producing a mu molded product having protrusions on the back surface, the back layer having the protrusions is integrally molded after the surface layer is formed. This eliminates the occurrence of sink marks due to volumetric shrinkage on the surface side of the protrusion, and has the excellent effect of making it possible to obtain a W resin molded product having smoothness comparable to that of a steel panel.

In addition, the molding space in which the protrusions of the vIi resin molded product are to be formed is constituted by a slide core that is movably provided on the back mold, and after the protrusion is formed, the resin molded product is Since it can be ejected, there is also the effect that workability in the manufacturing process is significantly improved.

[Brief explanation of drawings]

Figures 1 to 6 are flowcharts of the molding process of the method for manufacturing a resin molded product according to the first embodiment of the present invention, and Figures 7 to 9 are
The figure is a flow chart of the molding steps in the method for manufacturing a resin molded article according to the second embodiment of the present invention. /...8M resin molded product IC...Surface layer/b...Back layer 2...-Surface mold 2Iz...Molding surface of surface mold...Back surface Mold 11a...Molding surface B of the back mold...Protrusion 7...In the molding space...Slide core Z α...Molding surface of the slide core Applicant: Toyo Industrial Co., Ltd. calm

Claims (1)

[Claims] /, A method for manufacturing a resin N molded product having a protrusion on the back side, the surface mold having a molding surface forming the front surface of the resin molded product, and a molding surface forming the back surface of the WM resin molded product. and a slide core that is movably provided in the back mold and has a molding surface that can configure the molding space of the protrusion, and first, the molding surface of the slide core is molded into the back mold. The surface layer of the molded product is formed with a capitivity formed between the molding surface of the front mold and the molding surface of the back mold, and then the two molds are separated and , the slide core is inserted into the molding surface of the back mold to form the molding space of the protrusion, and the space formed between the surface layer attached to the front mold and the molding surface of the back mold is also molded with a trowel. The molded product is characterized in that the back layer of the product is formed integrally with the surface layer, and then both molds are completely opened, the slide core is made to protrude, and the WM MN molded product attached to the back mold is taken out. Method of manufacturing molded products.