JPH02145324A - Resin molded form printer and manufacture of printed foamable resin molding using the same - Google Patents

Abstract

PURPOSE:To decrease a facility investment and to reduce the production cost of a commodity by printing a resin molding in a mold simultaneously upon molding of the molded form by a mold. CONSTITUTION:In an injection mold formed of a first mold and a second mold sliding oppositely to the first mold for forming a cavity, the surface of an ink holding material 42 in which printing ink is absorbed on the inner wall of the cavity of at least one mold 10 is formed at a part to be printed of an ink permeable material 43, and covered at the other part than the part to be printed with a shielding member 47 composed of an ink impermeable material. Such a member 47 is supported by an elastic material 45. Foamable particles are filled in the cavity of the mold in which a printer composed in this manner is removably provided, then heated so that the particles are fusion-adhered or foamed and fusion-adhered to manufacture a foamed resin molding printed on its surface.

Description

[Detailed description of the invention] [Industrial application field] The present invention is applicable to in-mold bead foam molding, injection molding, blow molding,
The present invention provides an apparatus that prints on a molded product in a mold at the same time as manufacturing the molded product during resin molding such as vacuum forming, pressure forming, mantid die molding, etc. (including both secondary processing and secondary processing).

[Prior art]

In the printing method for injection molded products, the injection molded product such as a bucket or container obtained by injection molding into the cavity of a mold is removed from the mold, and then curved surface printing is performed on this injection molded product using photocurable ink. ing.

In addition, the cavity of the mold is filled with pre-expanded resin particles,
Next, the particles are foamed by steam heating and the particles are fused to each other to obtain an in-mold bead foam molded product. After releasing the mold,
This in-mold bead foam molding (fish boxes, fruit boxes, cold containers,
Gravure printing has also been applied to the surfaces of these lids, etc.).

If it were possible to print in the mold at the same time as injection molding or in-mold bead foam molding, it would have the advantage of reducing production costs, but in order to make continuous printing possible, the ink supply method had to be resolved. It has not been put into practical use.

Therefore, in reality, in injection molding, blow molding, high-air molding, and in-mold bead foam molding, a pre-printed label or blank is fixed to the inner surface of the mold cavity using static electricity, vacuum, or a physically forced support. The current situation is that a so-called in-mold label molding method is currently practiced, in which resin molding is performed and the label and blank are adhered simultaneously with the molding.

[Problem to be solved by the invention]

An object of the present invention is to provide a printing device that can print on a resin molded product in a mold simultaneously with molding for a long time without replenishing ink.

[Specific means to solve the problem]

In the present invention, the printing device is incorporated into the mold, and the ink in the printing device is oozed out by the resin injection pressure, resin foaming pressure, parison expansion pressure, etc. during molding, and the resin is applied to the surface of the resin molded product. Print at the same time as molding.

That is, the first aspect of the present invention is a printing device for printing a resin molded product that is removably provided on an inner wall surface constituting a cavity of a molding die, and the printing device has a printing device that absorbs printing ink. The surface of the ink holding material is formed by a shielding member that leaves the printed part as a space, or the printed part is made of an ink-permeable material, and the other part is covered with a shielding member made of an ink-impermeable material, and this shielding member is made of an elastic material. The present invention provides a printing device supported by

The second aspect of the present invention is a molding die consisting of a first die and a second die that slides opposite to the first die and forms a cavity, wherein at least one of the die The surface of the ink holding material that absorbs the printing ink on the inner wall surface of the cavity is a shielding member that leaves the printed area as a space, or the printed area is formed of an ink-permeable material, and the area other than the printed area is made of an ink-impermeable material. The cavities of a mold are covered with a shielding member, and the cavities of a mold are removably equipped with a printing device that supports this shielding member with an elastic body.The cavities of the mold are then heated to fuse or foam-fuse the foamed particles The present invention provides a method for manufacturing an in-mold foamed resin molded product whose surface is printed.

〔Example〕

Hereinafter, the present invention will be explained using the drawings.

FIG. 1 shows a mold apparatus for in-mold bead foaming molding. This mold device is composed of a female mold (first mold) 10 and a male mold (second mold) 20.
20, vapor transmission holes 11.21 are formed in the mold walls facing the cavity 30 formed when the molds 10 and 20 are closed, and chambers 12.22 are formed outside the mold walls.
is formed.

The chambers 12.22 of the male and female molds 10.20 are equipped with a steam introduction pipe 13.23, discharge pipes 14, 24, and a cooling water introduction pipe 1.
5.25 are connected respectively. Each of these tubes 13.
14, 15, 23, 24° 25 has on-off valves 13a, 14
a, 15a, 23a.

24a and 25a are respectively attached. and,
A filling gun 26 for filling expandable thermoplastic resin particles is attached to the male mold 20 side. Furthermore, a printing device 40 is provided approximately at the center of the female mold 10.

This printing device 40 constitutes a part of a female mold 10, for example, as shown in FIG. The ink holding material 42 is made of an ink-absorbing fibrous material such as a CMC sponge or a collagen sponge, or an open-cell porous material, and includes an ink permeable material 43 made of a sintered metal plate, a casing 44, and an elastic material 45.45.
It is stored between. A shielding member 47 (see FIG. 3) made of, for example, aluminum, iron, or plastic is arranged on the upper surface of the ink permeable body 43, leaving the printed portion as a space 48. This shielding member 47 is in contact with the cavity 30 surface, the casing 44 is in contact with the chamber 12 surface, the ink permeable body 43 is supported by an elastic body 45, 45, and the elastic body 45 is in contact with the casing 44 with an epoxy resin adhesive 46. is fixed to. The shielding member 47 on the cavity 30 side surface of the ink permeable body 43 is fixed so as to be flush with the cavity 30 side of the female mold IO, and the space 4 between the cavity 30 and the ink permeable body 43 is
8.48 to form a printed dial. 49 is a plug that closes the hole for replenishing the ink liquid.

This printing device 40 continuously performs molding, and when the density of the printing ink on the surface of the molded product (Fig. 4) becomes thin, the molding is interrupted, the mold is opened, and the bolts 41, 41, etc. are removed. Remove the printing device 40 from the female mold 10, and remove the plug 4 on the back side.
9 is removed, the ink liquid is refilled, the stopper 49 is put on, and the female mold 10 is reattached to the female mold 10 with bolts 41, 41, etc., making it easy to replenish the ink liquid. Although the plug 49 is provided outside the chamber of the mold in FIG. 1, the plug 49 may be provided in the shielding member 47 of the printing device.

As the ink permeable body 43, in addition to the above-mentioned sintered metal plate, a sintered plate of resin such as nylon or ceramics, a screen mesh wire mesh, etc. can be used. Further, as the elastic body 45, silicone rubber, natural rubber, vulcanized rubber, or spring is used.

FIG. 5 is a sectional view of another embodiment of the printing device, in which the same parts as in the previous embodiment are given the same reference numerals. A plate is used, and the area other than the printed area is covered with a shielding member 47.

Next, the steps of molding and printing will be explained. Using the printing device shown in FIG. 1 and the mold device shown in FIG. 2, first, male and female molds 10 and 20 are clamped. Next, male and female molds 10.
20 kg/n? is placed in advance in the cavity 30 formed by mold clamping of 20? Pre-expanded styrene resin particles (expandable thermoplastic resin particles) that have been pre-foamed are filled from the filling gun 26, and the filling port is closed. First, steam introduction pipe 2
3 on-off valve 23a and discharge pipe 14.24 on-off valve 14a
.

24a is opened and water vapor having a steam pressure of 0.3 kg/cdG is introduced for 5 seconds to discharge condensed water and remove air between resin particles.

Next, the on-off valve 24a of the discharge pipe 24 is closed, and the water vapor is released.
By introducing for 0 seconds, the condensate and air are evacuated more completely. As a result, both the male and female molds 10.20 are further preheated, and a portion of the pre-expanded styrene resin particles within the cavity 30 expands.

The on-off valve 13a of the steam introduction pipe 13.23 is opened to introduce steam for 5 seconds to sufficiently preheat the female mold 10 side.

Close the on-off valve 14a of the discharge pipe 14 while leaving 23a open,
Main heating is performed for 30 seconds to sufficiently expand and fuse the pre-expanded styrene resin particles to form a styrene resin foam molded product. During this expansion, the expanded particles fill the space 48 between the ink permeable body 43 and the shielding member 47 and the protruding characters 5
0 (see Figure 4). The swelling force of the particles is applied to the shielding member 47 and the ink permeable body 43, and the elastic body 45 is pushed down slightly, pressurizing the chamber storing the ink liquid, so that the ink liquid does not bleed through the ink permeable body 43. to print styrene resin in-mold foam molded products.

Next, the on-off valve 13a of the steam introduction pipe 13.23.

23a is closed to stop the supply of steam and end the heating. At this point, the on-off valves 14a, 2 of the discharge pipe 14.24
4a to bring the pressure in chamber 12.22 to the same pressure as atmospheric pressure. Thereafter, the inside of the chamber 12 is cooled down to 80° C. by evaporation of the water in the chamber 12 and adiabatic expansion of the water vapor. After that, the on-off valve 15a of the cooling water introduction pipe 15.25.

25a and open the chamber 12 of the male and female molds 10.20.
．． 10.2. 10.2.
0 and cool the molded product. Next, open the on-off valves 14a, 24a of the discharge pipe 14.24 to discharge water, and then
After cooling for a few seconds, the molded product was taken out from the mold to obtain a final product 60 as shown in FIG.

In addition, as a material for the expandable thermoplastic resin particles, pre-expanded polystyrene, expandable polypropylene, expandable polyethylene, pre-expanded ABS resin, etc. are used.

The printing method in the in-mold bead foam molding method has been described above, and this printing device has an injection pressure of 30 to 5001qr/a.
It is possible to incorporate it into a molding device that applies a pressure of -100 to -650 wHg to the entire mold, blow pressure of 3 to 6 kg/d1 during blow molding, and vacuum pressure of -100 to -650 wHg during vacuum forming, making it possible to print at the same time as molding. Of course.

〔effect〕

In the present invention, it is possible to simultaneously print on the molded product inside the mold at the same time as molding the resin molded product using a mold, and the equipment investment is small compared to the conventional method in which molding and printing were performed in separate processes. Moreover, the equipment area of the device can be significantly reduced, and the production cost of the product can be lowered.

[Brief explanation of the drawing]

Figure 1 shows a cross section of the mold device for in-mold bead foam molding, and Figure 2 shows
The figure is an enlarged partial sectional view of the 9 printing device inside the round frame of the molding die shown in Figure 1, Figure 3 is a partial plan view of the female mold, and Figure 4 is a partial cross-sectional view of the molded resin product. The perspective view, FIG. 5, is a sectional view of another printing device.

Claims (1)

[Claims] 1) A printing device for printing a resin molded product that is removably provided on an inner wall surface constituting a cavity of a molding die, the printing device comprising a resin molded product that absorbs printing ink. The surface of the ink retaining material is formed by a shielding member that leaves the printed part as a space, or by forming the printed part with an ink-permeable material, and covering the area other than the printed part with a shielding member made of an ink-impermeable material, and this shielding member is made of an elastic material. Supported printing device. 2) A molding die consisting of a first die and a second die that slides opposite to the first die and forms a cavity,
The surface of the ink retaining material that absorbs the printing ink on the inner wall surface of at least one mold cavity is formed with an ink permeable material or a shielding member that leaves the printed part as a space, and the printed part is made of an ink permeable material. In this method, foamed particles are filled into the cavity of a molding die that is covered with a shielding member made of an ink-impermeable material, and a printing device in which the shielding member is supported by an elastic body is removably installed, and then heated to cause the foamed particles to interact with each other. A method of manufacturing in-mold foamed resin molded products with printed surfaces by fusion bonding or foam fusion bonding.