JPS60168633A - Manufacture of thermoplastic resin container - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin container free of torsion, warping, etc., by a method in which in the manufacture of a video tape cassette, for example, a developed plate of thermoplastic resin is molded, a printing is applied to the developed plate in such a way so to forcily fix the printing ink, and the developed plate is made into a box form. CONSTITUTION:A developed plate 2 of a thermoplastic resin (e.g., polypropylene resin, etc.) is molded by extrusion into a long form by a T-die, and a fixed thickness of the thermoplastic resin flat plate so obtained is notched to form notches 13-16. Ruled lines 12 are then formed on the flat plate by compression molding or cutting process. A print is applied to the plate 2, the printing ink is forcibly fixed within 30min, and the plate 2 is bent at the ruled lines 12 into a box form. Since the average thickness of the ruled line is 5% or more thinner than the developed plate, or 0.15-1.5mm., the ruled line itself can keep its necessary rigidity and also the deformation to be encountered when the printing ink is forcibly fixed can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a unit of a certain volume such as a tape cassette for a video tape recorder, a floppy disk, a video disk, a digital audio disk, and a sheet of photosensitive material. The present invention relates to a method for manufacturing a thermoplastic resin container suitable for accommodating products such as film, photographic paper, and printed boards.

[Prior art]

Thermoplastic resin containers with small volumes such as those mentioned above can be molded into three-dimensional molding by direct molding, but cases that store items larger than a certain volume, such as tape cassettes for video tape recorders, for example. In this case, it is impossible to perform three-dimensional molding by direct molding, so a method of manufacturing from a spread plate is used.

In addition, the above-mentioned containers include the product name, product contents and description,
Patterns, company names, etc. are often printed, but such printing is done before manufacturing.

For example, when producing a development plate by extrusion molding,
A flat plate made of thermoplastic resin with a certain thickness and a size that allows cutting out multiple expansion plates is extruded from a T-die, and parts corresponding to the multiple expansion plates are printed on the flat plate. After applying and drying the printing ink,
Cutting or cutting each development plate of a certain size (hereinafter referred to as cutting)
Cut out the folds of each expansion plate (hereinafter referred to as the "key line part") by compressing or cutting, and create a notch by punching.
Further, depending on the case, the surface is subjected to foil stamping or embossing to create a printed development plate, which is then used to create a printed thermoplastic resin container.

In the above case, after printing on a flat plate, measures such as leaving it at room temperature for a day are taken to harden the ink.
If ink is fixed in a short period of time (for example, within 50 minutes) using hot air drying or infrared ray drying to increase productivity, the flat plate will become twisted and distorted, and this deformation will be particularly noticeable at the periphery of the flat plate. In this case, a considerable area of the peripheral edge of the flat plate must be cut and discarded, which is not only uneconomical in terms of materials, but also the resulting expanded plate is deformed to some extent, impairing its commercial value. Become.

Therefore, in such cases, there is a need for a measure that can fix printing ink in a short time without causing deformation of the spread plate.

On the other hand, in the case of extrusion molding as described above, after molding,
Not only is it inefficient due to the large number of processes such as cutting and forming the wires and notches, but the wires lack uniformity in strength and shape, cutting allowances and notches are created, and disposal is troublesome. There were some drawbacks.

Therefore, in order to eliminate these drawbacks, the present inventor previously proposed producing a developing plate of a thermoplastic resin shell by injection molding (Japanese Patent Application No. 58-26007). In other words, it has been considered difficult to injection mold a deployable plate with a wide area beyond the size of a plastic sheet, and no attempt has been made to do so, but it is now possible to make a deployable plate with a diagonal line or notch by injection molding. It has been found that by doing so, the drawbacks of the prior art as described above can be completely eliminated.

As a result of various studies, the inventor of the present invention discovered that in order to produce a developing plate made of thermoplastic resin in the extrusion molding described above, the developing plate was cut out from a flat plate, and after forming the diagonal lines and notches thereon, it was printed. Even if the printing ink is forcibly fixed in a short period of 30 minutes or less, the deformation caused by forced drying will be absorbed by the lines and cuts, and the printed development plate will not twist or distort. (I succeeded in
Moreover, this effect is also the same for the development plate having the diagonal line part and the cutout part produced by injection molding, which was proposed by the present inventor earlier, and by printing on the development plate obtained by injection molding,
The present invention has been achieved by discovering that even if printing ink is forcibly fixed for a certain period of time, a printed development plate with almost no deformation such as twisting or distortion can be obtained.

[Purpose of the invention]

Accordingly, an object of the present invention is to provide a method for manufacturing a printed thermoplastic resin container in which the printing process is performed in a short time and does not cause deformation such as twisting or distortion.

[Structure of the invention]

The above objects of the invention are achieved by the invention described below.

That is, the present invention produces a developing plate made of thermoplastic resin having a wire portion and a notch portion and having an average thickness of A3 to A3,
This is a method for producing a thermoplastic resin, which is characterized in that after printing on this, printing ink is forcibly fixed within 30 minutes, and then production is made from the developed plate.

In the present invention, it is preferable that the average thickness of the wire part is 5 cm or more thinner than the average thickness of the development plate and 0.15 to 5 m. In addition to maintaining the necessary rigidity, deformations when printing ink is forced to stick can be particularly reduced.

The present invention will be explained in detail below.

As the thermoplastic resin used in the present invention, polyvinyl chloride, polystyrene, various polyolefin resins (for example, substituted ethylene, polypropylene, or copolymers of these polymers and other resins) are used. In particular, polyolefin/based thermoplastic resins (including copolymers with other thermoplastic resins), polystyrene-based thermoplastic resins, or ABS-based thermoplastic resins, and mixed resins of two or more of these thermoplastic resins are preferably used. , most preferably various polypropylene resins, especially various nucleating agents at 0.01
A propylene/ethylene random copolymer resin containing ~2 parts by weight is suitable in terms of cost, printability, manufacturing accuracy, dimensional stability, wire strength, surface strength, rigidity, suitability for injection molding, etc. These thermoplastic resins contain various blowing agents, white pigments (titanium oxide, talc, mica, calcium carbonate, clay, etc.), various carbon blacks, and various colored pigments.
Various metal powders (aluminum powder, tin powder, aluminum paste, etc.), various organic or inorganic fiber substances such as various gold M fibers, glass fibers, and carbon fibers, various other coloring dyes, various antistatic agents, Various known additives such as various silicones, surfactants, lubricants such as sodium stearate, and antioxidants can be added.

Furthermore, the thermoplastic resin used in the present invention may contain carboxylic acids, dicarboxylic acids, their salts and anhydrides, and aromatic sulfonic acids in order to provide transparency and mechanical strength such as rigidity. salts and esters, aromatic phosphinic acids, aromatic phosphonic acids, and various other nucleating agents.

In the present invention, the developing plate is made from these thermoplastic resins, but as described above, extrusion molding or injection molding may be used. However, considering the simplification of the process, injection molding as described later is preferable. In either case, it is necessary to have a line and a notch on the development plate before printing, and if printing is performed in this condition, the development plate will not be distorted or deformed. 30
Printing ink can be forcibly fixed in a short time of less than minutes.

In the present invention, the K-line part and the notch part created by K as described above (various shapes may be applied as necessary)
Various printing methods (silk screen printing, offset printing, flexible printing, gravure printing,
Due to the need to print with 41 colors or more per frame using tampo printing, electrostatic transfer printing, hot stamping (foil stamping), transfer printing, inkjet printing, rotary roll printing, etc., primer coating and printing surface protection are required to improve printability. (may have a protective layer).

In order to forcibly fix the printing ink in the present invention, cold air,
Hot air, infrared irradiation, ultraviolet ray irradiation, electron beam irradiation, etc. are used, and in particular, assembling a continuous printing line after injection molding is effective in reducing manufacturing costs, inventory, and printing man-hours.

Next, the development plate used in the present invention will be explained.

In the present invention, as illustrated in FIG. 81, the printed thermoplastic resin container 1 in the shape of a #YY rectangular parallelepiped with an open opening on the - side is manufactured by molding and printing the developing plate 2 shown in FIG. It will be manufactured by drawing this.

In FIG. 2, the development plate 2 includes a front part 4, a back part 5, a left side part 6, a right side part 7, a bottom part 8, and a left side overlapping part 9.
, right side overlapping portion 10. After printing on the flaps 11.11a and the wired portions 12, printing ink is forcibly fixed thereon, and by manufacturing this, a thermally printed plastic resin container 1 as shown in FIG. 1 is formed. be done. In FIG. 1, the correspondence of each part of the expansion plate in FIG. 2 is shown except for the flaps 11, 11a and the highlighted portion 12.

According to one aspect of the present invention, a developing plate 2 as illustrated in FIG. 2 (x!~xl*Yl~Y3, etc. is not included)
In this method, a thermoplastic resin flat plate of a constant thickness is extruded into a long length using a T-die, and cut out, for example, 2 to 6 blank plates for making expanded plates. Attached is 9 notches 1
3, 14, 15. 16, and then cut out the wire part 12.
is formed by compression molding or cutting, or by first forming a wire portion and then cutting out a cutout portion. Further, depending on the case, the front portion 4 etc. may be subjected to embossing. The development plate 2 thus obtained is printed by the printing method described above, and the printing ink is forcibly fixed.

According to a second preferred embodiment of the present invention, the development has cutout portions 13, 14, 15, 16 and a dotted line portion 12 as shown in FIG. One plate or a plurality of plates 2 are produced simultaneously by injection molding, and the printing and forced fixation as described above are performed.

When injection molding is performed in the method of the present invention, the injection port (gate) for the molten thermoplastic resin containing aluminum powder is not limited to one location, but can be provided at multiple locations. By doing so, the flow of the aluminum powder-containing thermoplastic resin is improved during injection molding, and the occurrence of a boundary line where the flow of the thermoplastic resin joins, which is called a weld line, can be prevented. These injection ports (gates) are shown in Fig. 2 on the inside of the container to improve the fluidity of the thermoplastic resin in terms of the appearance of the container and in the structure where the diagonal line is provided only on the surface of the container as shown in Fig. 3. xl e ”N exl *Y
l # ”M (represented by the bin gate), or the product end of the cutout portions 13, 14, 15.16 (represented by the side gate), or the left and right overlapping portions 9.10 or the flaps 11.
It is desirable that the thermoplastic resin be formed at one or more locations on the front, back, and end portions of 11a, preferably in the vicinity of horizontally or vertically symmetrical positions, where the thermoplastic resin can flow to the four corners in approximately equal time. It is particularly desirable to provide the injection port (gate) for the thermoplastic resin at only one location, xl e Yl in FIG.

Moreover, if it is provided in two places, it is provided at the positions Yl and Y3 in FIG.

Another example of creating two locations is xl in Figure 2! It is also desirable to make it in the position of .

Note that Xl...X4 and 7t@...y4 are the distances between each gate.

In any case, in the present invention, the shape of the resin injection port (gate) is determined based on the shape of the developing plate, the fluidity (melt index) of the thermoplastic resin, the ease of generating gate marks, the ease of generating weld 2-in, etc. Since the number, position, and shape change, the present invention is not limited to the above description, and any number or shape can be adopted at any position on the expansion plate, and is suitable for injection molding and the surface of the container (visible to the eye) when manufactured. It is desirable to prevent the resin from appearing on the visible surface, both from the viewpoint of a uniform metallic appearance and from the viewpoint of the fluidity of the resin.

FIG. 4 is a schematic sectional view showing an example of an apparatus used for injection molding in the present invention.

Although this example illustrates a mold having one cavity for molding the expansion plate, the present invention is not limited to this, and molding cavities are provided on both sides of the fixed mold, and injection molding is performed from one injection tube. Use a double-stack mold that allows molten resin to be supplied to both cavities at the same time, or a multi-stack mold that increases the number of cavities and allows molten resin to be supplied from one or two injection tubes. be able to. Further, depending on the case, a vacuum injection molding method may be adopted in which an exhaust device is provided and the cavity is evacuated before supplying the molten resin.

The illustrated mold includes a fixed mold 21, a movable mold 22, an injection tube 23, a shell, a cavity 24 for molding a development plate between the fixed mold 21 and the movable mold 220, and a hot water molded in the fixed mold 21. The contained molten thermoplastic resin is supplied from the injection tube 23 to the cavity 24 through a passage 25 .

In the present invention, molding is performed by adding α01 to 5% by weight of a silicon compound such as polydimethylsiloxane, a surfactant such as saponin, or a lubricant such as a higher fatty acid metal salt such as sodium stearate to the thermoplastic resin. It is possible to improve the fluidity, moldability, and mold releasability during molding, as well as the slipperiness after molding.

In addition, adding an antistatic agent to the thermoplastic resin can prevent dirt and dust from adhering to the container, or adding a foaming agent to the thermoplastic resin can change the appearance and texture of the container. It is also possible to selectively improve the performance and reduce the weight.

In the present invention, the wire portion and notch portion (which may be shaped in various ways as necessary) are prepared by K as described above.
A printing layer is formed on the developing plate by using the various printing methods described above (if necessary, a primer may be applied to improve printability or a protective layer may be formed to protect the printed surface).
After that, cold air, hot air, each kamikaze, infrared irradiation, ultraviolet irradiation,
The printed layer is fixed to the development plate by electron irradiation or the like.

When manufacturing a thermoplastic resin container 1 as shown in FIG. 1 by the method of the present invention, it is preferable that the expansion plate 2 as shown in FIG. 2 has a cross-sectional shape as shown in FIG. 3. Further, in FIG. 3, the key lines are provided only on one side of the expansion plate, but they may be provided at symmetrical positions on both sides. In either case, the plate thickness t is generally from about 0.31 to about 3 fins, and the silicon line portion is preferably 5% or more of the average plate thickness t of the developed plate.
% or more, most preferably 50 inches or more, the thickness of the developing plate, which has notches and diagonal lines, will not get glued or twisted even if the printing ink is rapidly fixed to the developing plate by drying or chemical reaction after printing. The occurrence of this is particularly small, making drawing easy.

Therefore, in the present invention, the cooling efficiency of the developing plate 2, which is a molded product,
The board thickness is 0.3 to prevent glue, sink marks, and kinks and to ensure strength.
It is preferable that the thickness is 5-5, and the wire portion is preferably 5 or more inches with respect to the plate thickness t, in order to prevent warpage and sink marks when printing ink is fixed, to ensure fluidity of the thermoplastic resin, and to facilitate simultaneous kg-. It is desirable that the thickness be 15% or more, most preferably 30 inches or more, and from the viewpoint of strength, at least α1
It is desirable to ensure a thickness of - or more.

In the present invention, the front, back, entire surface or front part 4 is
, the outer or inner surfaces of the back surface portion 5, left side surface portion 6, right side surface portion 7, bottom surface portion B, etc. are selectively embossed, grooved, or recessed to improve the appearance and handleability. In conventional manufacturing methods, these were performed by embossing, but in the method of the present invention, these surface treatments can also be performed during molding.

〔Example〕

Next, in order to further clarify the effects of the present invention, examples in which injection molding is used are listed below.

(1) A double-stacked 4-cavity υ mold (the injection tube was provided above) having two molding plate injection molding cavities (one IAL and two IAL) as shown in FIG. 4 was used. In this case, the mold was designed so that the dimensions of each development plate were as follows. Resin inlet (
The gates were placed at two locations Yl r Ym inside the development plate in FIG.

Vertical and horizontal dimensions of the expansion plate: The longest part is 247m x 237m Thickness of the expansion plate = 0.8■ Dimensions of the lined part: Width 1.5m, depth 0.25m Cross-sectional shape of the lined part: As shown in Figure 3 Thing notch 13.1
Dimensions of 4: Length approximately 70 m, width 20 stitches Dimensions of notch 15.16: Polygon whose longest part is 37 m x 28 cm (2) Using this mold, molten thermoplastic resin of the following composition was injection molded: Polypropylene resin manufactured by Mitsui Petrochemical ■ (M knee 40f
/10 minutes)...96.8 weight Dimethylpolysiloxane manufactured by Shin-Etsu Silicone ■, KF-916 (product name)...
・11% by weight titanium oxide ・・・2% by weight, antistatic agent electro stripper manufactured by Kao Soap■
...α1% by weight (3) Print characters in two colors, black and orange, on the injection-molded development plate 2 using a silk screen printing method, and dry it with hot air at 50°C for several minutes to fix the printing ink to the development plate. Aluminum foil stamping was performed using a heat bar at 80°C. Next, this was assembled and the overlapping parts were welded using an ultrasonic bonding machine to produce a videotape cassette case with approximate dimensions of 192 m x 105 m x 28 m and a beautiful uniform silvery white metallic color.

According to the present invention, after printing, the printing ink was forcibly fixed by hot air drying in a short time, but the printing ink was distorted on the developing plate.
The container could be easily made without warping or twisting.

The present invention is not limited to the above-mentioned embodiments, and can be widely applied, for example, as shown below.

(1) The shape of the expansion plate is not symmetrical; for example, the shape of the front part and the shape of the back part may be different.

(2) Even if the thickness of the side part is the same as the remaining thickness of the silicon wire part, the strength can be maintained by overlapping and joining.

(3) The shape of the notch is rectangular, square, trapezoidal, semicircular,
It can be of various shapes such as semi-ellipse, equilateral triangle, isosceles triangle, and arrow shape.

[Brief explanation of the drawing]

FIG. 1 is an external view showing an example of a thermoplastic resin container manufactured according to the present invention, FIG. 2 is a plan view of a developing plate, and FIG. 3 is a sectional view of the developing plate taken along plane A-B in FIG. 2. FIG. 4 is a schematic sectional view showing an example of an injection molding apparatus used in the present invention. 1...Thermoplastic resin container 2...Development plate 12...
Key line parts 13 to 16... Notch part xl t xt T
X3 + Yl + Y3 ””Gate 21...Fixed mold 22...Movable mold 23...Injection tube 24...Cavity for molding the expansion plate 25...Runnet No. 1 Figure 2

Claims (1)

[Scope of Claims] 1) A developing plate made of thermoplastic resin having a diagonal line part and a cutout part and having an average thickness of A5 to 5 fins is prepared, and after printing is applied to this, printing ink is applied to the plate for 30 minutes. It was forcibly fixed within minutes, and then #! - A method for producing a thermoplastic resin. 2) The method for producing a thermoplastic resin container according to claim 1, wherein the average thickness of the C line portion is 5 cm or more thinner than the average thickness of the expansion plate, and cL is 15 to 1.5 cm. . 3) The above-mentioned development plate having a cross-section and a notch is manufactured by cutting a flat plate made of extruded thermoplastic resin into a desired size, and providing a cross-section and a notch on each cut piece. A method for manufacturing a thermoplastic resin container according to claim 1) or 2). The method for manufacturing a thermoplastic resin container according to claim 1) or 2), wherein the expansion plate having the cutout portion and the cutout portion is manufactured by injection molding.