JPS60162636A - Manufacture of thermoplastic resin container - Google Patents

Abstract

PURPOSE:To obtain an expanded plate having a metallic colour for a thermoplastic resin container, by mixing a thermoplastic resin having special physical properties and aluminium powder having a special particle size and a special volatile component followed by injection molding. CONSTITUTION:A thermoplastic resin used should have a melt index (M.I.) of 10g/10min and a flexural modulus of 5,000kg/cm<2>. The amount of aluminium powder to be dispersed in the thermoplastic resin is desirably 0.3-20wt% of the thermoplastic resin. The particle size of the aluminium powder should be 10mum or less and the volatile component thereof should be 1wt% or less, and if aluminium powder without this range is used, uniform distribution would not be obtained. When the thermoplastic resin composition containing this aluminium powder is injection molded, an expanded plate having a thickness of about 0.3-3mm., a metallic colour and lines or the like can be produced efficiently, from which a thermoplastic resin container good in appearance can be produced easily.

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 of manufacturing a thermoplastic resin container suitable for accommodating products such as film, photographic paper, IO printed boards, etc.

[Prior Art] Thermoplastic resin containers such as those described above with small volumes can be three-dimensionally molded by direct injection molding, but containers with a volume larger than a certain level, such as tape cassettes for video tape recorders, etc. In the case of a nurse who stores
Since it is impossible to perform three-dimensional molding by direct injection molding, a method is used in which boxes are manufactured from expandable plates.

Conventionally, the development plate for such synthetic resin containers is made by extruding a long synthetic resin plate from a T-die, printing it if necessary, and then cutting it into a plate of a certain size. The parts corresponding to the folds (hereinafter referred to as ``key line parts'') are compressed and shaded or cut, the notches are punched out, and in some cases, the surface is stamped with foil or embossed.

However, such conventional manufacturing methods require a large number of man-hours and are inefficient, lack uniformity in the strength of the silicon wire, surface shape, thickness of the developed plate, etc., and in terms of quality, the incidence of defective products is low. The height is high, and the cutting and shaping of the wires are done with force, resulting in scratches, the surface of the grooves on the wires becoming rough, and the appearance of the cutting surface, which has a poor appearance and reduced cutting allowance. Since the cut-out portion is discarded, there are inconveniences in terms of cost and industrial waste generation. Furthermore, in terms of quality, notches and other punched edges are crushed and cut scraps are generated, which fall off during use and adhere to the tape when storing video cassettes, etc. Dropouts (distortion of sound and image) occurred, and it was impossible to change the thickness of parts in order to differentiate them, and it was impossible to process special shapes and embossed fine letters and shapes.

In order to eliminate the above-mentioned drawbacks of the prior art, the present inventor first proposed that a developing plate for such a synthetic resin container be manufactured by injection molding (Japanese Patent Application No. 58-260).
No. 07). In other words, it has been considered difficult to injection mold a deployable plate with a wide area beyond a certain level using resin, 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 also been found that by doing so, the drawbacks of the prior art as described above can be completely eliminated.

On the other hand, for the purpose of imparting a metallic tone color to such synthetic resin containers and preventing static electricity, aluminum powder (aluminum powder is easily oxidized when it becomes fine and can cause explosions, etc. Since there is a risk of causing an accident, aluminum paste (generally used as an aluminum paste as described later) is applied to the surface by printing or the like.

Since the above method requires steps such as printing, which causes high costs, the present inventor blends aluminum powder into the molding resin composition and molds it when producing the spread plate by injection molding. By doing this, we attempted to create a development plate with a metallic wire that was applied with a metallic color at the same time as it was molded. However, such a developing plate has an average thickness of about 0.3 to 3 mm and an area of about 1 ooam" or more, and the wire has an average thickness of about 5% or more thinner than the average thickness of the developing plate. Therefore, if the molten resin composition is not poured uniformly and quickly from the gate to the molding cavity during pouring, the flow and distribution of the molten material will be uneven, especially when flaky aluminum powder is mixed. In this case, an irregular metal flow pattern occurs from the position of the pouring gate, and when pouring from two gates, for example, a boundary line is formed between the two gates due to the accumulation of aluminum powder. This will damage the appearance of the container.

Therefore, the present inventor conducted various studies in order to produce a thermoplastic resin molding board that is injection-molded using aluminum powder or aluminum paste and has a uniform metallic color, and also has an antistatic effect. As a result, the present invention was achieved.

[Purpose of the Invention] Therefore, the object of the present invention is to provide a method for manufacturing a thermoplastic resin container, which manufactures a thermoplastic resin container with a uniform metallic tone color by injection molding using aluminum powder or aluminum paste. Our goal is to provide the following.

Another object of the present invention is to provide a method for manufacturing, by injection molding, a developing plate for a container made of thermoplastic resin, which has a cross section and a notch and is painted in a uniform metallic tone.

[Structure of the Invention] The above objects of the present invention are achieved by the method of the present invention described below. That is, in the present invention, aluminum powder is
．． In a method for manufacturing a thermoplastic resin container, the method comprises producing a developing plate having a diagonal line portion and a notch line made of a thermoplastic resin containing 3 to 20% Juasahi by injection molding, and forming the same into a box. Particle size of aluminum powder is 10μ
Cb) The melt index (M, L) of the M plastic resin is 10 g/10 minutes or more, and the flexural modulus is 5 +000 K.
g/am or more, and (0) the average thickness of the developing plate is 0.3 to 3 mm.

The present invention will be explained in detail below.

The thermoplastic resin used in the present invention has a melt index (M, engineering) of 10 g/10 minutes or more and s, o o.

It has a bending modulus of IKg/am2 or more.

The proof, engineering, used here is J Engineering 5K7210 (ACTM
According to DI 23B-62', the flow rate when melted resin is flowed out at 230' O with a load of 2.16 Kg using an extrusion type frustometer through an Olycester with a diameter of 2.1 mm and a length of 8 mm. is measured and expressed in units of 8710 minutes.

In addition, the bending elastic modulus in the present invention is; fXBK-720
This is the measured value according to 3.

The thermoplastic resin used in the present invention has a melt index of 1 to 80, 20 to 60 g/10 min, particularly preferably 30 to 50 g/10 min.
It is preferable to use a polypropylene resin of 10 minutes or a polyoleain-based polymer containing 50 weights ff11 or more of such polypropylene resin. As the polypropylene resin, polypropylene, propylene-ethylene copolymer, propylene-ethylene random copolymer, propylene-02~olOα-olefin copolymer, chlorinated polypropylene, crosslinked polypropylene, etc. are used alone or as a mixture of two or more resins.

Furthermore, when the thermoplastic resin contains a polyolein-based polymer, the polyolefin-based polymer has a
g/10 minutes or more, or low-pressure low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, etc. are preferably included.

Furthermore, the thermoplastic resin used in the present invention can contain various additives depending on the purpose, such as nucleating agents, white or colored pigments, dyes, lubricants, ultraviolet inhibitors, and antioxidants. , electromagnetic shielding materials, seed increasers, inorganic fibers, etc.

In the present invention, aluminum powder is added to such a thermoplastic material.

Aluminum powder is used in the form of fine powder or fine flakes, but aluminum paste is generally used because it is easily oxidized and poses a risk of explosion. Therefore, the term aluminum powder in the present invention also includes aluminum paste.

Aluminum paste here is a paste made in the presence of white spirit and a small amount of stearic acid when making aluminum powder using the ball mill method.
In addition, the term "aluminum powder" refers to molten aluminum made into powder by an atomizing method, granulation method, rotating disk dropping method, evaporation method, or the like, as well as aluminum foil made into flakes by pulverizing it.

Next, when dispersing the above-mentioned aluminum powder (including aluminum paste, the same applies hereinafter) into a thermoplastic resin, a known method is applied in which aluminum powder is added to the resin and stirred and mixed during the heating and melting process. Ru.

The amount of γrut'+um powder added is 0.6 to 2.0% of the thermoplastic resin from the viewpoint of suitability for injection moldable packaging materials and manufacturing cost.
It is desirable that the content be 0.0 trillion i%, particularly 0.5 to 10% by weight.

The particle size of the aluminum powder used in the present invention is 1
0/71!1 or less (if the aluminum powder is in the form of 7 flakes, the major axis of the flake surface is taken as the particle size) or less, the plunging component is one double pall or less, and aluminum powder outside this range is used. However, there are drawbacks such as not being able to obtain a uniform distribution, and irregular flow patterns due to aluminum flakes and the like are likely to occur.

The amount of aluminum powder added is 0.6 to 20% of the thermoplastic resin from the viewpoint of injection moldability, packaging material suitability, and manufacturing process.
It is desirable that the amount is 0.5 to 10% by weight, especially 0.5 to 10% by weight. If the amount added is less than 0.6%, the antistatic effect will be low, and there will be problems with light blocking and moisture proofing properties, and if it is more than 20%, the physical strength, heat sealability, flatness, etc. of the molded plate will be affected. causes defects.

As described above, according to the present invention, by injection molding using a thermoplastic resin composition mixed with aluminum powder, a thickness of about 0.6 to 3 mm and an area of 100 cm can be obtained.
It is possible to efficiently produce the above-mentioned developing plate having the uniform metallic color holder 5, silicon wire, etc., and it is possible to easily produce a thermoplastic resin container with a good appearance.

EMBODIMENT OF THE INVENTION Hereinafter, the embodiment of producing the expansion plate by this invention is demonstrated with reference to drawings.

In the present invention, a thermoplastic resin container 1 having an approximately rectangular parallelepiped shape with an open opening on the negative side as shown in FIG. 1 is manufactured by box-forming a developing plate 2 shown in FIG.

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.
, the right side overlapping part 10, the flap 11.11a, and the key wire part 12, and by making these into a box, the first
A thermoplastic resin container 1 as shown in the figure is formed. 1st
In the figure, the correspondence of each part of the unfolding plate in FIG.

Conventionally, in cases where a container 1 made of thermoplastic resin as shown in FIG. After printing and drying, cut the material, cut out the notches marked with diagonal lines in Figure 2, shape them, punch out the cutouts with the lines attached, or cut the notches into uncut rectangles. After forming the plate, the lined part 12 is formed by compression shading or cutting, and then the hatched cutout part 16°14.1 is formed.
5 and 16 were punched, and in some cases, the front part 4 and the like were embossed to create a development plate, which was then manufactured into a box.

According to the present invention, the developing plate 2 as shown in FIG. 2 is formed by injection molding into a polygonal shape having a cutout portion, a diagonal line portion 12, and, depending on the case, an uneven front portion. After this is produced and subjected to printing or the like if necessary, it is made into a box to produce a thermoplastic resin container 1 as shown in FIG.

As mentioned above, various thermoplastic resins can be used as the thermoplastic resin used in injection molding in this button-measuring method, including polypropylene resin 1. Polyoleaine thermoplastic resin (including copolymers with other thermoplastic resins), polystyrene thread thermoplastic resin, or AES thermoplastic resin A mixed resin of two or more of these thermoplastic resins is used, especially 50% by weight % or more has a melt index of 1 to 80
and propylene containing 0.01 to 2 parts by weight of each yuzu nucleating agent.
Ethylene and random copolymer resins are suitable in terms of cost, printability, manufacturing accuracy, dimensional stability, silicon wire strength, surface strength, rigidity, suitability for injection molding, etc.

In the present invention, these thermoplastic resins are blended with 0.6 to 20% aluminum powder, but if necessary, these thermoplastic resins may contain various blowing agents and white pigments (oxidized titanium, talc, mica, calcium carbonate, clay, etc.), various carbon blacks, various colored pigments, various gold M fibers, various organic or inorganic fiber substances such as glass fibers, carbon fibers, and various other colorings. Various additives such as dyes, various antistatic agents, various silicones, surfactants, lubricants such as sodium sterate, and antioxidants can be added.

Furthermore, 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.

This improves the flow of the aluminum powder-containing thermoplastic resin during injection molding, and prevents the occurrence of a merging boundary line of thermoplastic resin flows called a weld line. 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 case of a structure in which the diagonal line is provided only on the surface of the container as shown in Fig. 6. Ta X engineering, X2゜x3 y Yl
t Y3 (typically Bin Gate), or notch 1
3, 14, 15, 16 product ends (represented by side gates), or left and right overlapping parts 9, 1° or flaps 11.1
It is desirable that the thermoplastic resin be formed at one or more locations on the front, back, and end portions of 1&, preferably in the vicinity of left-right 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, X2YH in FIG.

In addition, if it is installed in two places, it is installed at the positions Y and Y3 in Fig. 2.

Another example of setting two points is the xl in Figure 2 and the fluidity (melt index) of heat-reproducible resin containing Minilam powder.
The number, position, and shape of resin injection ports (gates) vary depending on the ease with which gate marks and weld lines occur. Any number or shape can be used for the position, and it is important to consider the suitability of injection molding and to prevent it from appearing on the surface (visible surface) of the container when it is made into a box.The uniform metallic appearance also ensures resin flow. It is also desirable from a sexual point of view.

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

Nao, in this example, a mold having one expandable plate molding cavity is illustrated, but the present invention is not limited to this, but molding cavities are provided on both sides of the fixed mold, and a single injection cylinder is used. There are double stack molds that can simultaneously supply molten resin containing arsenium powder to both cavities, and multiple stack molds that have further increased the number of cavities and can supply molten resin from one or two injection tubes. A stacking mold can be used. Further, depending on the case, a vacuum injection molding method may be adopted in which an exhaust system is provided and the cavity is evacuated before supplying the molten resin.

The illustrated mold is composed of a fixed mold 21, a movable mold 22, and an injection tube 26. A cavity 24 for molding a spread plate is formed between the fixed mold 21 and a movable mold 220, and Molten thermoplastic resin containing aluminum powder is supplied to the cavity 24 from the injection tube 23 through the passage 25 .

In the present invention, 0.01 to 5% by weight of a lubricant such as a silicon compound such as polydimethylsiloxane, a surfactant such as saponin, or a higher fatty acid metal salt such as sodium stearate is added to the thermoplastic resin together with aluminum powder. This improves fluidity, moldability, and mold release properties during molding, as well as fX.
, the slipperiness after shaping can be improved. Additionally, by adding an antistatic agent to the thermoplastic resin, it is possible to make it difficult for dirt and dust to adhere to the container, or by adding a foaming agent to the thermoplastic resin, the appearance of the container can be changed to improve its feel and make it lighter. It may also be optionally possible to do so.

In the present invention, various printing methods (silk screen printing, offset printing, Flexo printing, gravure printing, tanbo printing, curved surface printing ζ electrostatic transfer printing, hot stamping (foil stamping) transfer printing, inkjet printing, rotary roll printing, etc.) to create a printing layer of one or more colors of each type (if necessary, printability (For improvement, a primer coating or a protective layer to protect the printed surface may be applied.) After that, the printed layer is fixed to the developing plate by cold air, hot air, various types of air, infrared irradiation, ultraviolet irradiation, electron irradiation, etc. It is also possible to assemble a continuous printing line after injection molding, which reduces production costs,
This is effective in reducing inventory and printing man-hours.

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. 6. In addition, in Fig. 6, the wires are provided only on one side of the development plate, but they may be provided at symmetrical positions on both sides.The plate thickness t is generally Q, from about 5 mm to about 3 mm. , the C line portion is 5% or more, preferably 15% of the average plate thickness t of the developed plate.
% or more, most preferably 60% or more, it is possible to prevent warping or twisting even if the printing ink is rapidly fixed to the development plate with notches and diagonal lines by drying or chemical reaction after printing. The generation is small and box making is easy. In the present invention, the plate thickness of the developing plate 2, which is an injection molded product, is 0.3 to 3 mm to ensure cooling efficiency, prevention of warping, sink marks, and sunburn, and ensuring strength.
In order to prevent warpage and sink marks when the printing ink is fixed, and to ensure the fluidity of the thermoplastic resin and at the same time facilitate box manufacturing, the wire portion should be 5% or more, preferably 15% of the plate thickness t.
As mentioned above, it is necessary to reduce the thickness by 60% or more most preferably, and from the viewpoint of strength, it is necessary to ensure a thickness of at least 0.1 mm 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 8, etc. are selectively embossed, grooved, and four-parted 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 at the time of creation molding.

[Example] Next, in order to further clarify the effects of the present invention, examples are listed below.

←) A double-stacked four-cavity mold with two expansion plate injection molding cavities on each side 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. The resin injection port (gate) was located at one location Yl on the inside of the expansion plate (the inner bottom surface in contact with the articles to be housed in the box) in FIG. 2.

Vertical and horizontal dimensions of the expansion plate: The longest part is 247 mm x 237 mm Thickness of the expansion plate is 0.8 mm Dimensions of the cross section: Width 1.5 mm, length 0.25 mm Cross-sectional shape of the cross section: As shown in No. 61iiKi Dimensions of notches 13 and 14: Length approximately 7Qmm, width 2Qmm Dimensions of notches 15 and 16: Polygonal body with longest part 37mm x 28mm) Using this mold, a molten thermoplastic resin having the following composition was injection molded: Mitsui Petrochemical Co., Ltd. polypropylene resin, grade N
O.J-950D (M knee 40g/10 minutes)...
89.8% by weight Dimethylpolysiloxane, IC manufactured by Shin-Etsu Silicone Co., Ltd.
y 96 (Product name)...0.1wt% Aluminum paste 60wt% Polypropylene resin (masterbatch hammer fat)...10wt% Kao Soap (Match) Loaded antistatic agent electro stripper
...0.1 Jusha% (3) Letters in two colors, black and red, were printed on the injection-molded development plate 2 using a silk screen printing method, and the printing ink was fixed to the development plate by drying with 50010 hot air. After pressurizing with an 80) 0 hot plate and stamping the product name with aluminum foil, assemble this and weld the overlapping parts using an ultrasonic bonding machine to create a beautiful uniform silver-white metallic color with approximate dimensions of 192 mm x 105 mm x 28 mm. A case for a videotape cassette having the following characteristics was manufactured.

When manufacturing 600,000 boxes, the manufacturing cost is reduced to 45% compared to the conventional manufacturing method that includes cutting and punching processes, and the incidence of defective products is reduced by reducing ear loss, cutting/cutting loss, and cage loss. The knitting rate was 1% in the method of the present invention, compared to 11% in the conventional method including loss etc.

[Effects of the Invention] The method of the present invention reduces the number of man-hours as described above, thereby lowering manufacturing costs, and provides a uniform metallic color with greatly reduced warping and twisting of the developing plate, as well as an antistatic effect. Excellent thermoplastic resin containers can be manufactured with greater efficiency.

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

CL) The shape of the expansion plate is not bilaterally 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 cutout portion can be various shapes such as a rectangle, a square, two trapezoids, a semicircle, a semiellipse, an equilateral triangle, an isosceles triangle, and an arrow shape.

(4) The residual thickness of the wired portion may be partially increased to improve the flow of resin during injection molding.

(5) Processing the surface of the mold to create a transparent window in one or more places on the development plate, or marking the inner and outer surfaces of the case with the product name, company name, picture, etc. - It can be made to have shapes (texturing) such as horizontal stripes, lattice patterns, fine-grain surface textures, etc. More than 210 types of concrete textured samples include ``Bearron Grain'' published by Tokyo Bear Four Co., Ltd.

(6) During injection molding, thermoplastic resins are copolymers,
It can be a mixed resin of two or more types of thermoplastic resins.

(7) One or more types of colored pigments or colored dyes can be added to the thermoplastic resin.

(8) Injection molding of the development plate (including vacuum injection molding in the entire mold)
After that, printing and labeling processes can be selectively added before and after the box manufacturing process to add marks and letters.

[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 the expansion plate, and FIG. 6 is a cross-sectional view of the expansion 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. Expansion plate 12. Key line portion 16-16.. Notch portion xl e x2 v x3
y Yl r "3" Gate 21...Fixed type 22
・・Moving mold 26・・Injection tube 24・・Cavity for molding the development plate (6 people) No. 3 Amendment to figure procedure August 2q, 1980 1, Indication of the case 1982 Patent Application No. 16959 26 Name of the invention Method for manufacturing thermoplastic resin containers 3. Person making the amendment Relationship to the case: Name of patent applicant (520) Fuji Photo Film Co., Ltd. Kasumigaseki Building Post Office Post Office Box No. 49 1) "Invention" in the specification ``Detailed explanation column'' will be amended as follows. 0, page 4, line 5, add ``container'' after ``contain''. O In the fourth line from the bottom of page 5, "during pouring" is corrected to "during resin injection." Add "injection" after "molten resin composition" on the sixth line from the bottom of page 5. 0, page 6, line 1, replace “pouring gate” with “resin injection gate”
and correct it. 0 9th Negative In the 9th line from the bottom, "to a thermoplastic material" is corrected to "to a thermoplastic resin." 0 Page 10, 8th line from the bottom to 7th line from the bottom, "Injection moldability, packaging material suitability" is corrected to "Injection moldability, packaging material suitability". 0, page 15, line 5, "X2" is compensated as r X2 Y2 J.

Claims (1)

[Scope of Claims] 1) A heat-generating plate made of a thermoplastic resin containing 0.3 to 20% by weight of aluminum powder and having a wire portion and a cutout portion is produced by injection molding, and the plate is made into a box. In the method for manufacturing a plastic resin container, (a) the particle size of the aluminum powder is 10 pm or less;
Volatile components are 1% by weight or less, (b) Melt index of thermoplastic resin (M, Engineering,)
is 10g/10 minutes or more, flexural modulus 5,000 Kg
/, a m or more, and (0) the average thickness of the developing plate is 0.3 to 3 mm. 2) 0.3 to 0.3% aluminum powder in the thermoplastic resin
The method for manufacturing a thermoplastic resin container according to claim (1), characterized in that the thermoplastic resin container contains 20% by weight. 3) The thermoplastic resin container according to claim 1 (η or 2), wherein 50 weight percent or more of the thermoplastic resin is a resin with a melt index of 1 to 80. Production method. 4) The method for manufacturing a thermoplastic resin container according to claim (3), wherein the thermoplastic resin other than the polypropylene resin is a polyolefin polymer.