JPH0789526A - Multi-layer packaging container with cat's eye effect - Google Patents

Abstract

PURPOSE:To provide a cat's eye type decorative effect by laminating an internal layer made of a synthetic resin being colored by a pigment which reflection- colors by the absorption and scattering of a light, and an external layer made of a synthetic resin with transparency, which selectively emits a specified chromatic color by the interference of a light. CONSTITUTION:A wall 1 of a container consists of an external layer 2 and internal layer 3. The external layer 2 is constituted of a continuous phase 4 made of a thermoplastic resin, and a mica titanium pigment 5, being a scale form thin film, which is dispersed in the continuous layer 4 and emits a chromatic color by the interference of a light. In the meantime, the internal layer 3 consists of a synthetic resin layer which is colored in a hue being different from the chromatic color, and the synthetic resin layer is constituted of a continuous phase 6 and a coloring pigment particle 7 being dispersed in the continuous layer 6. Then, a reflection-coloring of the internal layer 3 can be seen through the external layer 2 with transparency, and at the same time, a specified interference color of the external layer 2 by the interference of a light can be seen. By this method, an outstanding cat's eye type decorative effect can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic multi-layer packaging container having a specific decorative effect, that is, a cat's eye light reflecting effect.

[0002]

2. Description of the Related Art A pearl essence such as a mica titanium pigment is added to a plastic molded product to impart a pearly luster to this molded product.
It has been known for a long time from Japanese Patent Publication No. 4 etc., and many proposals have already been accepted for applying this technique to a plastic hollow container.

For example, JP-B-53-41596 discloses an outer layer 2 made of a transparent synthetic resin mixed with a predetermined amount of pearl essence such as mica or titanium for producing a pearl decoration effect. A pearl decoration in which a main body 1 is constituted by an inner layer 3 formed of an opaque synthetic resin of a desired color laminated inside an outer layer 2 is described.

Further, Japanese Patent Publication No. 59-44255 discloses a container having a modified polyolefin resin as a decorative layer.

[0005]

The above-mentioned prior art has been successful in that the outer surface of a plastic hollow container or the like exhibits a deep and deep pearly luster. The pearlescent container uses the interference of light by pearl essence, but it is an elegant but conspicuous decorative effect, and it is displayed in shops and the like.
Alternatively, when the consumer picks it up, it is not particularly attractive and unattractive, and it is not sufficiently satisfactory in terms of decorative effect.

Therefore, an object of the present invention is to provide a plastic multi-layer packaging container having a decorative effect, that is, a cat's eye effect, which is completely different from the conventional pearlescent container. Another object of the present invention is that when light is incident on the surface of a container, lines or bands of interference color light appear in the highlight part of the container, and the highlight part and its peripheral part have different hues. To provide a plastic multi-layer packaging container as shown.

[0007]

According to the present invention, an inner layer made of a synthetic resin colored with a pigment that is reflected and colored by absorbing and scattering light, and a specific chromatic color are selectively emitted by the interference of light and are transparent. It consists of an outer layer made of a synthetic resin that has the property of seeing the reflected color of the inner layer through the outer layer having transparency, and at the same time, a specific interference color due to the light interference of the outer layer is visible. There is provided a multi-layer packaging container having a decorative two-color coloring effect.

According to the present invention, an inner layer made of a synthetic resin colored with a pigment, and an outer layer made of a synthetic resin having transparency selectively exhibiting a specific color by interference of light and a synthetic resin having transparency. It consists of a laminate including the outermost layer of, and the so-called "cat's eye" is obtained by visually observing the reflected color of the inner layer through the outer layer having transparency and at the same time visualizing the specific interference color due to the interference of the light of the outer layer. There is provided a multi-layer packaging container having a decorative two-color coloring effect.

As an outer layer that selectively exhibits a specific color,
It is preferable to orient a scaly thin film having a high refractive index in the surface direction of the outer layer to develop an interference color. Most preferably, a mica titanium pigment is used as the scaly thin film, and the mixing ratio is 2 in unit area conversion. To 300 mg / dm ² , particularly preferably,
It is 10 to 100 mg / dm ² . As the flaky thin film having a high refractive index, flakes of a micro-multilayered laminate of a plurality of types of resin layers having different refractive indexes are used, and the mixing rate thereof is 0.1 to 250 mg / dm ^{2 in} terms of unit area, and particularly preferably 1 to 70 mg / dm ² .

The inner layer is lightly colored with a lightness of 7 or more and a saturation of 3 or less, and the outer layer is processed to have a matte tone in order to impart a good waxy luster to the product such as the inside of an alabaster or shellfish. be able to.

Further, a transparent coating layer containing a predetermined amount of an ultraviolet absorber may be provided in close contact with the outer side of the multi-layer packaging container in order to minimize yellowing of the outer layer. When the outermost layer is provided, the weight average molecular weight (M
It is preferable to use a propylene-ethylene random copolymer having a w) in the range of 25 × 10 ^{4 to} 33 × 10 ⁴ and an ethylene content of 2 to 8% by weight from the viewpoint of transparency and gloss, and It is preferable that the outermost layer be smoothed by melting treatment of the container after molding.

As the outermost layer, a blend containing a continuous phase (A) made of a propylene resin and a dispersed phase (B) made of an ethylene resin in a volume ratio of A: B = 90: 10 to 55:45. When used, a frosted appearance can be obtained at the same time. In addition, when a thermoplastic polyester is used as the resin forming the outer layer and the inner layer or further the outermost layer, the container is excellent in appearance such as transparency and gloss.

[0013]

In FIG. 1, which shows an example of the cross-sectional structure of the multi-layer packaging container of the present invention, the wall 1 of this container is composed of an outer layer 2 and an inner layer 3. The outer layer 2 is composed of a continuous phase 4 of a thermoplastic resin, and a scale-like thin film that emits a chromatic color due to the interference of light dispersed therein, for example, a mica titanium pigment 5. On the other hand, the inner layer 3 is composed of a synthetic resin layer colored in a hue different from the above chromatic color, and is composed of, for example, a continuous phase 6 of synthetic resin and color pigment particles 7 dispersed therein. Also,
In FIG. 2 showing another example of the cross-sectional structure, the outermost layer 8 made of a transparent resin is provided on the outer surface of the outer layer 2, and the others are the same as in the case of FIG.

According to the present invention, by forming a multi-layered packaging container by the combination of the outer layer and the inner layer, a special decorative effect, that is, a cat's eye effect as shown in FIG. 3 can be obtained. That is, in FIG. 3, when light rays are radiated from the outer surface side of the hollow container 10, the reflected light 12, 12 from the inner layer is visually recognized throughout, but at the same time, the reflected light of the interference color from the outer layer is displayed in the central portion of the container. The line or band 11 is clearly recognized in the form of being superimposed on it. This line or band 11 of light is chromatic and has glitter, and the number of the line or band may be one or plural depending on the number and position (viewing position) of the light source. Appears in the center.

In FIG. 4 for explaining the generation of interference chromatic color due to the mica titanium pigment 5, the mica titanium pigment 5 is a mica substrate 15 having a large aspect ratio and a titanium dioxide fine particle deposition layer formed on the surface of the mica substrate (hereinafter It is also called a titanium layer) 16, 16.

When a light ray is incident on the mica titanium pigment, the light ray that is incident on and reflected by the surface of the titanium layer 16 interferes with the light ray that is incident and reflected on the interface 17 between the titanium layer 16 and the mica substrate 15. Produces light. There is a fixed relationship between the thickness of the titanium layer 16 and the chromatic color generated by light interference, and this relationship is as shown in Table 1 below.

[0017]

[Table 1]

In the present invention, it is preferable that a scale-like thin film of titanium mica pigment or the like is present with the outer layer being oriented in the plane direction,
This makes it possible to emphasize a chromatic interference color that is clear and has glitter. FIG. 7 is a sketch based on a micrograph showing a dispersed state of the mica titanium pigment dispersed in the outer layer resin in Example 1, and the line length in the figure is 10 μm. From FIG. 7, the mica titanium pigment particles are on the resin surface (paper surface).
The fact that they are preferentially oriented becomes clear. On the other hand, the inner layer 3 is colored with a coloring pigment or a white pigment (including white coloring) and is opaque as a whole, and the outer layer 2
It gives reflected light of different hue from the chromatic color.

In the multi-layer container of the present invention, the cat-eye-like decorative effect as shown in FIG. 3 has been found as a phenomenon, and the reason for this has not been clarified yet, but the present invention Estimated as follows. That is, in FIG. 5 for explaining this decorative effect, each symbol has the following meaning.

Description of two-color coloring such as "cat's eye" ・ Description of reference A: Incident light B: Surface reflected light (highlight) C: Interference light (color) D: Diffuse reflected light (coloring of pigment coloring layer) E : Absorbed light x: Line of sight 8: Surface gloss layer 2: Outer layer 3: Inner layer (pigment coloring layer) 5: Interference coloring type mica titanium oxide foil 5a, 5b: Mica titanium oxide foil oriented in a direction different from the line of sight

Description of Two-Color Vision Incident light A is surface-reflected light B which is specularly reflected on the surface of the gloss layer 1 and becomes intense highlight light. Since the surface reflected light B is a strong highlight, it is preferentially viewed over the pigmented light D ′ of the inner layer 3. Incident light A is reflected in multiple layers by the mica titanium oxide foil 5 of the intermediate layer (outer layer) 2 and emits an interference color C. Because of the high brightness of the interference color C, the interference color C of the mica titanium foils 5a and 5b oriented in a direction different from the line-of-sight direction x is seen more preferentially than the pigment coloring light D ″ of the inner layer 3. Gaze direction x
Not visible from. The intermediate layer 2 and the substantially transparent layer are substantially transparent except for the color development part of the interference color (specific color light of red, blue, yellow, etc.) C of the mica titanium foil 5 which is preferentially viewed as strong light from the line-of-sight direction x. The pigmentation of the inner layer 3 visible through the clear mica titanium foil 5 and the surface gloss layer is visible.

FIG. 6 shows, for each container having an outer layer of a resin composition containing a mica titanium pigment showing interference colors of yellow, blue and red, wavelengths of 300 to 1000 n using an integrating sphere.
It is a graph which shows the result of having measured the diffuse reflection spectral characteristic of m, and it is clear that the interference color characteristic of each pigment actually appears.

As described above, according to the present invention, an extremely clear and glittering cat's eye effect can be obtained.
The decorativeness and commercial value of the plastic container can be enhanced.

According to one embodiment of the present invention, the above-described mica-like titanium pigment is used as the scaly thin film which produces an interference color. In this case, as the mica-like titanium pigment, one that produces a constant chromatic color, for example, a constant chromatic interference color such as red, blue, and yellow should be used, and for that purpose, the thickness of the titanium layer in the mica titanium pigment is used. It is better to use the one that is as constant as possible.

In the multi-layer container of the present invention, the weight of the titanium mica pigment per unit area of the outer layer is 2 to 300 mg described above.
/ Dm ² , preferably 10 to 100 mg / dm ² . The abundance of the mica titanium pigment is defined by the weight per unit area because this expression form most appropriately expresses the multiplicity of the pigment in the layer thickness direction.

That is, if this amount is larger or smaller than the above range, the cat's eye effect tends to be reduced as compared with the case where the amount is within the above range.

Of course, the scale-like thin film for interference color used in the present invention is not limited to the mica titanium pigment as long as it produces an interference color. As a preferable example of such a scale-like thin film, flakes of a micro-multilayer laminate of a plurality of types of resin layers having different refractive indexes can be used. In this flake, the flakes are of a size that can be visually recognized, and since the flakes are a mixture of hues having interference colors such as red, blue, and yellow, when the flakes are mixed in the outer layer resin, the hues are different. A unique cat's eye effect with chromatic interference colors is obtained.

Further, in the multi-layer container according to the present invention, the outer layer may be processed into a matte or matte shape in order to impart a good waxy luster to the product such as the inner surface of an alabaster or shellfish. The cat's eye effect further emphasizes the good waxy luster of the inside of the shell.

The multi-layer container of the present invention has the scale-like thin-piece-containing outer layer and the colored resin inner layer as essential constituent layers, but may contain any other layer. For example, if a coating layer, especially a thermoplastic resin layer having excellent transparency, or an ultraviolet absorber-containing resin coating layer for preventing yellowing of the resin is further provided on the mica titanium pigment-containing outer layer, it is more sustained over time. The cat's eye effect is obtained.

As the outermost layer, gloss (JIS K7
105, incident angle 60 °) 8% or less of a thermoplastic resin layer, that is, a matte layer can be used to give a good blur gloss, and for example, combine with an inner layer colored with a brightness of 7 or more and a saturation of 3 or less. By doing so, it is possible to add a good waxy luster to an item such as the inside of an alabaster or shellfish, and by combining it with an inner layer colored with a lightness of less than 7, it is possible to give a silky luster that is soft and has a good item quality. it can.

As the outermost layer, gloss (JIS
K7105, incident angle 60 °) 70% or more, especially 80%
A clear gloss can be imparted by using the above thermoplastic resin layer, that is, the super gloss layer.

The color development of the outer layer is caused by the interference of light, so that it is unlikely to undergo discoloration or fading. Further, since the inner layer is protected by the outer layer, discoloration due to ultraviolet rays or the like is unlikely to occur. Therefore, the container of the present invention has an advantage that a sustained decorative effect can be obtained.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The multilayer packaging container of the present invention comprises an outer layer made of a thermoplastic synthetic resin mixed with flaky flakes that emit chromatic color due to light interference, and a thermoplastic resin colored in a hue different from the chromatic color. It is composed of a laminated body of a synthetic resin inner layer and an outermost layer of a transparent thermoplastic resin provided on the outer layer as necessary.

The outer layer which emits a specific chromatic color and has transparency can be realized by using an ordinary pigment or dye. However, the color development of the outer layer in this case is only a reflection color and cannot be visually recognized at the same time as the reflection color of the inner layer, and it is always a mixture of the reflection color of the inner layer and the reflection color of the outer layer. This color mixture is visible on the entire wall of the container and does not change depending on the viewing angle.
For this reason, it is preferable to incorporate a scale-like thin film, that is, pearl essence into the outer layer.

[Flake-like thin film] Mica titanium pigment is preferably used as a scale-like thin film to be contained in the outer layer to generate a chromatic color by interference of light, but natural or synthetic pearls are also usable. Essence can be used. Mica titanium pigment is a mica (3Al ₂ O ₃ · K ₂ O.
6SiO ₂ · nH ₂ O) is used as a nucleus, titanium oxide hydrate is deposited on the nucleus, and this is fired,
It is titanium dioxide. The titanium dioxide layer on the surface may be anatase type or rutile type.

Mica is characterized by being flaky crystals having a cleavability, a thickness of 1 μm or less, and an aspect ratio of 50 or more, and a thin layer of a titanium pigment having a large refractive index on this surface. By forming, the chromatic interference color as shown in Table 1 can be obtained according to the layer thickness.

As another pearl essence, fish scale foil or resin micro-multilayered flakes can be used. The latter micro multi-layered structure is a multi-layered structure in which a plurality of types of resins having different refractive indexes, such as acrylic resin and polyester resin, are multi-layered in a microscopic thickness.
It is manufactured by the method described in Japanese Patent No. 78323. The flakes have a thickness of 5 to 50 μm and a side size of about 0.1 to 0.5 mm. This micro-multilayer flake is commercially available from The Dow Chemical Company.

[Coloring Pigment] The coloring agent contained in the inner layer imparts to the inner layer a hue different from the chromatic color of the outer layer by the mica titanium pigment. Examples of colorants are as follows.

Black pigment; carbon black, acetylene black, lamp black, aniline black, iron trioxide, yellow pigment; zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, Orange Pigment; Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Balkan Orange, Indance Rembrilliant Orange RK, Benzidine Orange G, Indance Rembrilliant Orange GK, red pigment; red iron oxide, cadmium red, mercury cadmium sulfide , Permanent Red 4R, Resole Red,
Pyrazolone red, watching red calcium salt,
Laked D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, Purple Pigment; Manganese Purple, Fast Violet B, Methyl Violet Lake, Blue Pigment; Ultramarine Blue, Cobalt Blue, Alkali Blue Lake, Victoria Blue Lake , Phthalocyanine blue partially chlorinated, fast sky blue, metal-free phthalocyanine blue, indanthrene blue BC, green pigment; chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green, white pigment; zinc white, oxidation Titanium, antimony white, zinc sulfide, extender pigment; barite powder, barium carbonate, clay, silica, white carbon, talc, alumina white. These pigments may be used alone or in combination of two or more.

[Resin Composition for Inner Layer] As the resin for the inner layer, any thermoplastic resin used in this type of packaging container, for example, olefin resin, styrene resin, AB
Examples thereof include S resin, polyester resin, polyamide resin, nitrile resin, vinyl chloride resin, and polycarbonate resin.

Of these resins, thermoforming is easy,
Moreover, it is an advantage of the present invention that an excellent decorative effect can be given to a general-purpose olefin resin which is advantageous in terms of manufacturing cost. As the olefin resin, low-, medium- or high-density polyethylene, isotactic polypropylene, linear low density polyethylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1.
Copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer), ethylene-acrylic acid ester copolymer Alternatively, there may be mentioned blends of these, and among these, blow molding grades, extrusion molding grades, and injection molding grades are used according to the molding method.

Among these olefin resins, the propylene resin has a better surface gloss than other olefin resins, has a low internal haze, and is excellent in transparency, so that the resin of the outer layer of the present invention. Is suitable as As the propylene-based resin, in addition to homopolypropylene, propylene and other α-olefins such as ethylene and butene-1,
Examples thereof include copolymers with pentene-1, hexene-1, etc., particularly copolymers with ethylene, such as random or block copolymers.

The resin for forming the outer layer has a weight average molecular weight (Mw) of 25 × 10 ^{4 to} 33 × 10 ⁴ , particularly 29 ×.
10 ⁴ to olefin resin in the range of 32 × 10 ^4,
It is particularly preferable to use a propylene resin. The weight average molecular weight can be determined by obtaining a molecular weight distribution curve using gel permeation chromatography and using polystyrene as a standard to calculate the weight average molecular weight using a universal calibration method. Also,
Propylene-based copolymers, particularly propylene-ethylene / random copolymers having the above-mentioned weight average molecular weight are suitable for this purpose. The above random copolymer has an ethylene content of 2 to 8% by weight, particularly 3 to 5%.
Weight% is suitable.

The mica titanium pigment is generally 0.2 to 10% by weight, particularly 1 to 3% by weight, based on the resin for constituting the outer layer.
It is better to blend in the amount of. That is, when it is less than the above range, the cat's eye effect is not sufficiently expressed, while when it is more than the above range, the cat's eye effect is not sufficiently expressed.

In the production of the resin composition for the outer layer, extreme mixing and kneading such that the fine structure of the mica titanium pigment is destroyed should be avoided. For this purpose, a masterbatch containing a relatively high concentration of mica titanium pigment is produced,
This masterbatch is preferably kneaded with the resin for forming the outer layer and used for molding.

[Inner Layer Forming Resin Composition] Inner Layer (Base Layer)
As the forming resin, any of the resins described for the outer layer forming resin is used, but the inner layer forming thermoplastic resin is
It is used without concern about transparency and surface gloss. Generally, as the resin for forming the inner layer, a resin having less uneven thickness and drawdown property is used in view of blow moldability and the like, and among the above-mentioned olefin resins, those satisfying the above requirements are used.

As the inner layer resin, a propylene resin, particularly homopolypropylene or the above-mentioned propylene copolymer is used. The content of propylene unit in the whole polymer is 85 mol% or more, particularly 90 mol% or more, and when the melt flow rate (MFR) is polypropylene, it is 10 g.
/ 10 minutes or less is desirable. Further, as another example of the polyolefin resin constituting the inner layer, high density polyethylene having an MFR of 2 g / 10 min or less can be used.

The colorant is preferably used in an amount of 0.5 to 5% by weight, particularly 1 to 3% by weight, based on the inner layer resin.
That is, when it is less than the above range, it becomes difficult to bring a sufficient difference in hue with the outer layer, and the cat's eye effect is not sufficiently expressed, while when it is more than the above range, the cat's eye effect is also expressed. Is not enough,
The impact resistance of the container also tends to decrease.

As a suitable example of the resin for the inner layer, an inner layer colored with a lightness of 7 or more and a chroma of 3 or less can be mentioned.
As a result, it is possible to add a good glossy feeling such as the inside of an alabaster or shellfish. As another example,
An inner layer colored to have a lightness of less than 7 can be mentioned, which can impart a fine silk luster. Of course, the inner layer is not limited to this example.

[Outermost Layer Forming Resin] As the outermost layer forming resin used as desired, those mentioned for the outer layer forming resin and the inner layer forming thermoplastic resin and other resins may be used. Generally, the outermost layer resin is preferably excellent in transparency.

As a suitable example of the resin for the outermost layer, a thermoplastic resin layer, that is, a matte layer having a gloss (JIS K7105, incident angle 60 °) of 8% or less, particularly 6% or less can be used. It can impart good blur gloss or waxy gloss. Further, as another example of the outermost layer, a thermoplastic resin layer having a gloss of 70% or more, particularly 80% or more, that is, an ultra-gloss layer can be used, whereby a clear gloss can be imparted. Of course, the outermost layer is not limited to this example.

A suitable example of the mat layer resin is a blend of a propylene-based continuous phase forming resin (A) and an ethylene-based dispersed phase forming resin (B). In general, A: B = 90: 10 to 55:45, preferably 85:15 to 60:40 in a volume ratio. Further, it is advantageous for the continuous phase forming resin (A) to have a higher melting point or softening point than the dispersed phase forming resin (B) from the viewpoint of giving a frosted appearance.

As the propylene resin, a homopolymer of propylene or a random or block copolymer of propylene and other olefins such as ethylene, butene-1,2-methylpentene-1 is used. It
The propylene-based polymer may be used alone or in combination of two or more. The propylene content of the propylene-based polymer is preferably 90% by weight or more. The propylene-based polymer is particularly preferably an ethylene-propylene block copolymer, which generally comprises a homopropylene polymer block and an ethylene-containing polymer block bonded thereto. The ethylene-containing polymer block may be composed of a homopolyethylene block of ethylene alone or a random copolymer block of ethylene and propylene mainly containing ethylene. In short, ethylene in the ethylene-containing block,
It may be contained in an amount of 3 to 10% by weight.

On the other hand, as the ethylene-based polymer, in addition to low-density-, medium-density- or high-density polyethylene, a linear low-density to medium-density copolymer which is a copolymer of ethylene and a small amount of other α-olefins. Density polyethylene or a copolymer of ethylene and another monomer, for example, a vinyl-based or acrylic-based monomer, such as an ionomer, EVA or EEA is used. The ethylene polymer may be used alone or in combination of two or more kinds. Further, the ethylene content of the ethylene polymer is preferably 90% by weight or more.

As the resin capable of forming the super glossy layer, ethylene-propylene / random copolymer can be mentioned, and the preferable one is ethylene content of 2 to 8% by weight, particularly 3 to 5% by weight. %, Weight average molecular weight (M
There is a propylene-ethylene / random copolymer having w) in the range of 25 × 10 ^{4 to} 33 × 10 ⁴ . As will be described later, this outermost layer is smoothed by the container melting process after molding. In order to minimize yellowing of the outer layer, a predetermined amount of an ultraviolet absorber can be added to the outermost layer.

[Layered Structure] In the present invention, the layered structure of the container includes an outer layer, an inner layer or an outermost layer, but other layers may be included in addition to these. For example, it should be understood that various functional layers may be provided as an intermediate layer between the outer layer and the inner layer. For example, an intermediate layer of a gas barrier resin can be provided between the outer layer and the substrate via an adhesive resin layer.

That is, a gas barrier resin can be incorporated in the multilayer structure in order to impart gas permeation resistance to oxygen and the like to the container to be formed. As a gas barrier resin, the oxygen permeability coefficient (PO2) is generally 5.5 x
10-12 cc ・ cm / cm2 ・ sec ・ cmHg or less, especially 4.5 × 10
-12 cc · cm / cm 2 · sec · cmHg or less, especially an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 50 mol% and an unsaponified vinyl ester residue content of 5 mol% or less, , The number of amide groups per 100 carbon atoms is 3
A homopolyamide, a copolyamide or a blend thereof, which is contained in the range of 30 to 30, especially 4 to 25, is preferably used. Of course, the above-mentioned ethylene-vinyl alcohol copolymer and polyamide can also be used in the form of a blend, and within the range that does not impair the essence of this, for example, 20% by weight or less, other thermoplastic resins can be used. It is also possible to blend and use a resin, for example, a polyolefin or a resin that imparts adhesiveness to the polyolefin.

An oxygen absorbent-containing resin layer, a desiccant-containing resin layer, or the like can be provided as an intermediate layer in place of or together with the intermediate layer, and the regrind (scrap) generated during blow molding can be provided. The resin) may be used as an intermediate layer for reuse.

In the multilayer container of the present invention, the thickness ratio of the outer layer to the thickness of the entire vessel wall is 1 to 30%, particularly 5 to 20%, and the minimum thickness is preferably 30 μm or more. When the thickness is smaller than the lower limit, the cat's eye effect is not sufficiently obtained, while when it is larger than the upper limit, the cat eye effect is not sufficient.
Further, the blow moldability of the container is deteriorated, and the cost is disadvantageous. The total thickness of the vessel wall differs depending on the application and the site of the container, and cannot be specified unconditionally.
It is desirable that the thickness is in the range of 1 to 1500 μm. The thickness of the outermost layer provided on the mica titanium pigment-containing layer is generally 20.
It is preferably in the range of to 300 μm.

[Production Method] According to the present invention, the resin composition for forming the inner layer is used as a substrate, the resin for forming the outer layer is used as the outer layer, and if necessary, the outermost resin is used as the outermost layer. Mold into multilayer packaging. Of course, when an intermediate layer or an adhesive resin layer is interposed between the base and the outer layer, these resins are also laminated at the same time.

For producing the multilayer laminate, a coextrusion method, a co- or sequential injection method, an extrusion coating method, a sandwich lamination method, etc. can be used. That is, the multilayer packaging container of the present invention can be manufactured into a bottle-shaped or tube-shaped container by melt-extruding a multi-layer parison and blow-molding this in a split mold. Further, a cup-shaped container can be manufactured by forming a multilayer sheet by melt extrusion and then subjecting this sheet to vacuum forming, pressure forming, plug assist forming, and the like. Also, a tubular container can be manufactured by extrusion tube molding.

The manufacturing method is not limited to these methods, and it is also possible to manufacture a preform by a co-injection molding method and then blow-mold it to manufacture a stretched multilayer bottle. Similarly, injection multi-layer packaging containers such as caps and jars can be manufactured by the two-color molding method.

A typical bottle blow molding will be described. In coextrusion, a number of extruders corresponding to the types of resins are used, and a plurality of molten resin streams are combined in a multi-layer multi-die to produce a mixture outside the dies. Extrude into. A circular die is used as the die, and the extrusion temperature is a temperature higher than the melting point of the higher melting point of the resin used and lower than the decomposition temperature, but in the case of a propylene resin, it is generally 180 to 230.
A temperature of ° C is suitable.

If the extrusion temperature is too high, the drawdown tendency of the parison becomes remarkable, while if it is too low, sharkskin tends to be generated due to melt fracture, but according to the present invention, the extrusion temperature is usually used. It is possible to prevent the occurrence of drawdown, flow marks, and sharkskin.

The extruded parison is then blow molded in a blow mold having a sandblasted surface while it is still in the molten state. This blow molding is generally performed by using a pair of split molds having a parting surface, pinching off the parison with the split molds, and injecting a pressurized fluid into the enclosed parison. By using a blow mold with a sandblasted surface, the outer layer can be processed to a matte tone to add a good waxy luster to the product such as the inside of an alabaster or shellfish. The average depth roughness of the outer surface layer is preferably in the range of 5 to 30 μm.

The cavity surface of the blow mold is a sandblast surface in order to prevent the resin to be molded from sticking to the mold cavity surface and to effectively perform air bleeding between the mold surface and the resin surface. However, the particle diameter of the glass beads used for sandblasting is preferably in the range of 50 to 500 μm, particularly 75 to 200 μm from the above viewpoint.

As the pressurized fluid used for blow molding, pressurized air is generally used, but if desired, an inert gas such as nitrogen, steam or other fluid can be used, and the pressure is 4 to 10 kg / cm. ^It should be ² (gauge). The blow mold can be forcibly cooled with cooling water or the like.

The blow molding is not particularly limited, but it is desirable to use a rotary molding machine in terms of efficiency. In this rotary molding machine, a large number of split molds are arranged around the circumference, and the split molds are provided so as to be rotatable in a fixed direction and openable and closable. The thermoplastic resin parison is extruded from the die head in the tangential direction with the locus of the center of the split mold. At this tangential position, the split mold is open, and the parison supplied is sandwiched between the split molds and blow molding is performed. . After the blow molding, the split mold is opened and the molded product is discharged.

When forming the super-gloss outermost surface layer, it is melt extruded into a parison and then blow molded in a blow mold having a sandblasted surface while it is still in the molten state. Immediately after molding, the outermost surface of the blow molded product is heat-melted. This surface melting treatment is to smooth the outer surface of the blow-molded product by eliminating the unevenness corresponding to the uneven pattern on the sandblasted surface of the mold. Although any heating means known per se can be used for the heat treatment, the flame (flame) treatment is excellent in that the mechanism is simple and the outer surface can be efficiently heated in a short time.

It is important that the flame treatment is carried out in the state of a complete reducing flame in that it does not cause combustion or oxidation of the molten parison, and the fuel is city gas, propane gas, liquefied natural gas, liquefied petroleum gas, etc. Any fuel gas of is used. In the present invention, the temperature of the outermost surface of the blow molded product is set to 70
It was found that heating to 0 ° C. or higher, particularly 800 ° C. or higher is useful for improving the glossiness of the surface layer portion, and no effect is obtained at 500 ° C. or lower. The temperature of the flame used is not particularly limited as long as the surface layer reaches the above temperature, but a temperature of about 1600 ° C. was suitable as an example. The heating time may be an extremely short time for the blow-molded product to pass through the burner, and it can be said that the heat treatment is sufficient when the outermost surface of the blow-molded product reaches the above temperature.

[0071]

The present invention will be described in the following examples.

Example 1 As the outer layer, 2% by weight of a mica titanium pigment (pale yellow) was blended, the ethylene content was 4%, and the weight average molecular weight was 30 × 10 ^4.
Propylene-ethylene random copolymer of the above is fed to the extruder for the outer layer, MI1.5 propylene-ethylene block copolymer containing 1% by weight of a white pigment as the inner layer is fed to the extruder for the inner layer, Two layers of molten parison were molded at a resin temperature of 190 ° C. The surface of this molten parison was in a smooth state without sharkskin or flow marks. This parison is blow-molded in a blow mold in which the inner surface of the mold is blasted with glass beads having a particle size of 180 μm to 75 μm to prevent air traps, and the average wall thickness is 800 μm and the internal volume is 500 cc as shown in FIG. A two-layer bottle having an outer layer thickness of 50 μm was molded. When the molded bottle was observed under irradiation with light rays, an excellent cat's eye effect as shown in FIG. 2 was obtained, in which the periphery was dull white and the center was brilliant yellow.

Example 2 A blend of 80% by weight of a propylene-ethylene block copolymer having MI = 2 and an ethylene content of 8 mol% and a high density polyethylene having a density of 0.96 was used as an outer layer material. As the inner layer material, a propylene-ethylene block copolymer having MI = 1.5 is used. 2% by weight of mica titanium pigment (pale blue) was blended with the outer layer material and supplied to the extruder for the outer layer.
1% by weight of white having a saturation of 1.5) is blended and supplied to the extruder for the inner layer. These are coextruded at a resin temperature of 190 ° C,
Two layers of parison were molded. This parison is blow-molded in a blow mold in which the inner surface of the mold is blasted with glass beads having a particle diameter of 500 μm to 250 μm in order to impart a shell-like appearance and prevent air traps, as shown in FIG. A two-layer bottle having an average wall thickness of 800 μm, an inner volume of 500 ml and an outer layer thickness of 50 μm was molded. When the bottle after molding was observed under irradiation of light rays, a good waxy luster like that of the inside of a shell was obtained on the entire bottle.

Example 3 As the outermost layer, an ethylene-propylene random copolymer having an ethylene content of 4% and a weight average molecular weight of 30 × 10 ⁴ blended with 0.05% by weight of a benzotriazole type ultraviolet absorber was used for the outermost layer. A bottle was molded in the same manner as in Example 1 except that it was fed to the extruder and a three-layer multiple die was used. The outermost layer had a thickness of 60 μm. When the molded bottle was observed under irradiation with light rays, an excellent cat's eye effect as shown in FIG. 2 was obtained, in which the periphery was dull white and the center was brilliant yellow. In addition, this bottle was excellent in the sustainability of the cat's eye effect.

Example 4 The outermost layer had an ethylene content of 4% and a weight average molecular weight of 2
An ethylene-propylene / random copolymer of 7.1 × 10 ⁴ was supplied to the extruder for the outermost layer, and 2% by weight of a mica titanium pigment (pale yellow) was blended as the outer layer to obtain an ethylene content of 4
%, A propylene-ethylene random copolymer having a weight average molecular weight of 30 × 10 ⁴ was supplied to the extruder for the outer layer, and the inner layer was blended with 1% by weight of a white pigment, MI 1.1 ethylene-propylene block copolymer. The coalescence was supplied to the extruder for the inner layer, and a three-layer molten parison was molded at a resin temperature of 190 ° C.

In order to prevent air trapping and fusion, the inner surface of the mold has a particle size of 180 μm to 7 μm.
By blow molding in a blow mold blasted with 5 μm glass beads, the average wall thickness is 950 μm, the inner volume is 150 ml, and the thickness of the outermost layer and the outer layer are 5 respectively.
Three-layer bottles of 0 μm and 60 μm were molded. The 60 ° gloss at this time was 52%.

The outermost surface of the blow-molded product molded in this manner was subjected to a melting treatment to eliminate the uneven pattern corresponding to the sandblasted surface of the mold, and smoothing was performed. As a result,
The 60 ° gloss was improved to 80%, the desired gloss was obtained, and a deep cat's eye effect could be expressed.

As the outermost layer, a weight average molecular weight of 36 × 10
^When the propylene-ethylene / random copolymer of 4 was used, sharkskin tended to be generated on the surface of the molten parison, and the outermost layer had a weight average molecular weight of 22.
When a × 10 ⁴ propylene-ethylene / random copolymer was used, a tendency of generation of flow marks was observed.

Example 5 As the outermost layer material, an ethylene-propylene / random copolymer having an ethylene content of 4% and a weight average molecular weight of 30 × 10 ⁴ blended with 0.05% by weight of a benzotriazole type ultraviolet absorber, an outer layer material As a propylene-ethylene random copolymer having an ethylene content of 4% and a weight average molecular weight of 30 × 10 ⁴ containing 2% by weight of a mica titanium pigment (pale yellow), and M containing 1% by weight of a white pigment as an inner layer.
I 0.6 ethylene-propylene block copolymer is used, the outermost layer extruder having a diameter Φ35, the outer layer extruder having a diameter Φ35, the inner layer extruder having a diameter Φ75, three-layer three-layer feed block, T Width 350 mm, thickness 1.2 mm (outermost layer: outer layer: inner layer = 180 μm: 150) by a multi-layer sheet forming device composed of a die, three vertical rolls and a take-up machine.
(μm: 870 μm).

This sheet is heated by infrared rays at 190 ° C.
It is heated to 1, and a plug-assisted vacuum / pneumatic one-piece thermoformer is used, and the outer diameter is 75 mm and the bottom diameter is 52 m.
A cup-shaped container having a height of 70 mm and an average thickness of the body wall of 0.4 mm was formed. The thickness of the body wall is 60 μm: 50
μm: 290 μm. A deep cat's eye effect was developed on the outer surface of the body wall.

Example 6 As the outermost layer material, a low-density polyethylene simple substance with MI = 1.3 and d = 0.92, the same polyethylene mixed with 2% by weight of a mica titanium pigment (pale yellow) as the outer layer material, and as the inner layer Using the same polyethylene containing 1% by weight of a white pigment, an outermost layer extruder having a diameter of Φ40 (L / D = 25), an outer layer extruder having a diameter of Φ40 (L / D = 25), a diameter of Φ7
An outer diameter of 39 mm (outermost layer: outer layer: inner layer =) by an inner layer extruder of 5 (L / D = 32), a three-layer / three-layer die head, a sizing / cooling machine, a take-up machine, and a cutter. 40 μm: 50 μm: 400 μm)
Was molded into a multilayer tube. Die head extrusion temperature is 18
The temperature was 0 ° C. and the take-up speed was 9.5 m / min. The tube was provided with a shoulder and a nozzle by a tube shouldering machine. A deep cat's eye effect appeared on the outer surface of the extruded tube.

Example 7 A co-injector capable of arbitrarily controlling the timing of main injection and sub-injection was used in the production of a multi-layer preform. Polyethylene terephthalate (PET) with an intrinsic viscosity of 0.75 containing 2% by weight of mica titanium pigment (light blue) was supplied to the sub-injector, and the same PET with 1% by weight of white pigment was added.
The material was fed to the main injection machine.

First, the PET containing the fused mica titanium pigment was first injected into the cavity by the sub-injector, and then the PET material mixed with the white pigment was injected at a slightly higher injection pressure with a delay of 1 second than the primary injection. It was injected into the cavity from the main injection machine. Finally, by using the sub-injector again, at a slightly lower injection pressure than in the primary injection, P containing the titanium mica pigment was blended.
The ET material was secondarily injected to form a multi-layer preform of 2 layers and 3 layers having a thickness of 4 mm.

This multilayer preform was heated to about 98 ° C. and biaxially stretch blow-molded in a length of 2 and a width of 3 to form a bottle having an internal volume of 500 mL. Body thickness is 0.3m
In m, the layer structure was 75 μm: 150 μm: 75 μm. On the outer surface of this bottle, the cat-eye effect with the gloss and depth peculiar to PET appeared.

Example 8 MI = 2 and ethylene content of 8 mol% as the outermost layer
80% by weight of propylene-ethylene block copolymer
And a high density polyethylene having a density of 0.96 g / cc were fed to the extruder for the outermost layer, and 2% by weight of a mica titanium pigment (blue) was blended as the outer layer to obtain an ethylene content of 4
%, A propylene-ethylene random copolymer having a weight average molecular weight of 30 × 10 ⁴ was supplied to the extruder for the outer layer, and 1% by weight of an off-white pigment having a lightness of 8 and a saturation of 1.5 was blended as an inner layer, MI 1 The ethylene-propylene block copolymer of 0.5 was fed to the extruder for the inner layer to give a resin temperature of 19
Three layers of molten parison were molded at 0 ° C.

In order to give a shell-like appearance to this parison and prevent air traps, the inner surface of the mold had a particle size of 500.
When blow-molded in a blow mold blasted with glass beads of μm to 250 μm, a good waxy luster like the inside of a shell with a solid or high-grade appearance with a gloss of 6% is obtained. It was

Example 9 Except that the color of the inner layer resin was gray and the colors of the outer layer containing the mica titanium pigment were blue, red and yellow, respectively.
A multilayer bottle was produced in the same manner as in. The diffuse reflection spectral characteristic of this multilayer container was measured. Tsushima UV-310 for measurement
Using a 0PC spectrophotometer, a wavelength of 300 using an integrating sphere
The range from nm to 1000 nm was measured. The spectral characteristics of the diffuse reflection light from the outer surface of each container were measured, and the diffuse reflection light from the inner surface of the container was measured to obtain the spectral characteristics of the gray resin of the inner layer. The spectral characteristics of the outer layer containing the mica titanium pigment shown in FIG. 5 were obtained by numerically subtracting the diffuse reflectance spectral characteristics of the inner layer resin from the spectral characteristics of the diffused reflected light on the outer surface of each container. Visible light range from 400nm to 7
Between 00 nm, there are characteristic absorption peaks in each pigment due to the interference of the mica titanium pigment, and the complementary colors corresponding to these absorption wavelengths are visually recognized.

[0088]

According to the present invention, a special decorative effect, that is, a cat's eye effect can be obtained by forming a multi-layered packaging container by the combination of the titanium mica pigment-containing outer layer and the colored inner layer. That is, when light is incident on the hollow container,
In the center of the container, a line or band of chromatic light due to the reflection of the inner layer, and the reflection interference color of the outer layer are simultaneously developed around it,
It is very brilliant and has a distinctive, cats-eye effect.

Since the color development of the outer layer is due to the interference of light, it is hard to discolor and fade, and since the inner layer is protected by the outer layer, it is hard to discolor and fade due to ultraviolet rays and the like, and a permanent decorative effect can be obtained. There is also. Therefore, the container of the present invention is effective for increasing the commercial value of the container as a container for storing cosmetics, various chemicals, various foods, and the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a sectional structure of a multilayer packaging container of the present invention.

FIG. 2 is a cross-sectional view showing another example of the cross-sectional structure of the multilayer packaging container of the present invention.

FIG. 3 is an explanatory view showing a special decorative effect, that is, a cat's eye effect in the multilayer packaging container of the present invention.

FIG. 4 is an explanatory diagram illustrating generation of an interference chromatic color due to a mica titanium pigment.

FIG. 5 is an explanatory diagram for explaining the occurrence of a cat's eye decoration effect.

[FIG. 6] Diffuse reflectance spectral characteristics at wavelengths of 300 to 1000 nm were measured using an integrating sphere with respect to each of the containers having an outer layer of a resin composition containing a mica titanium pigment showing interference colors of yellow, blue and red, respectively. It is a graph which shows a result.

FIG. 7 is a sketch of a micrograph showing a dispersed state of titanium mica pigment particles in a multilayer resin in Example 1.

[Explanation of symbols]

 1 Container Wall 2 Outer Layer 3 Inner Layer 4 Thermoplastic Resin Continuous Phase 5, 5a, 5b Mica Titanium Pigment 6 Synthetic Resin Continuous Phase 7 Coloring Pigment Particles 8 Transparent Resin Outermost Layer 10 Hollow Container 11 Chromatic Light Lines or Band 12 Surrounding reflection interference color 15 Mica substrate 16 Titanium dioxide fine particle deposition layer

Claims (11)

[Claims] 1. An inner layer made of a synthetic resin colored with a pigment that reflects and develops light by absorbing and scattering light, and an outer layer made of a synthetic resin that selectively emits a specific chromatic color due to interference of light and is transparent. , The multilayer having a so-called "cat's eye" decorative two-color coloring effect by allowing the reflected color of the inner layer to be viewed through the outer layer having transparency and at the same time the specific interference color due to the light interference of the outer layer to be viewed. Packaging container. 2. The multilayer packaging container according to claim 1, wherein a scale-like thin film having a high refractive index is orientated in a plane direction of the outer layer as an outer layer selectively exhibiting a specific color, whereby an interference color is exhibited. 3. A mica titanium pigment is used as the scale-like thin film having a high refractive index, and the mixing ratio thereof is 2 to 3 in terms of unit area.
00 mg / dm ² , particularly preferably 10 to 100 m
The multi-layer packaging container according to claim ² , wherein g / dm ² is used. 4. The flakes of a micro-multilayered laminate of a plurality of types of resin layers having different refractive indexes are used as the flaky thin film having a high refractive index, and the mixing ratio thereof is 0.1 to 25 in terms of unit area.
0 mg / dm ² , particularly preferably 1 to 70 mg / dm ² .
The multi-layer packaging container according to claim ^{2, which} is 2. 5. The inner layer is lightly colored with a lightness of 7 or more and a saturation of 3 or less, and the outer layer is processed to have a matte tone so as to give a good waxy luster of an alabaster or the inside of a shell. The multi-layered packaging container according to claim 1, which comprises: 6. A transparent coating layer containing a predetermined amount of an ultraviolet absorber is provided in close contact with the outer side of the multilayer packaging container so as to minimize yellowing of the outer layer. The multilayer packaging container described in. 7. An inner layer made of a synthetic resin colored with a pigment, an outer layer made of a synthetic resin having transparency selectively exhibiting a specific color by interference of light, and an outermost layer of the synthetic resin having transparency. It is composed of a laminated body containing the two layers, and it is possible to see the reflected color of the inner layer through the transparent outer layer and at the same time to see the specific interference color due to the interference of the light of the outer layer. A multi-layer packaging container having a coloring effect. 8. The outermost layer has a weight average molecular weight (Mw) of 25.
× 10 in the range of ⁴ to 33 × 10 ⁴ and a propylene ethylene content of from 2 to 8 wt% - multilayer packaging container according to claim 6, wherein the ethylene random copolymer. 9. The multi-layered packaging container according to claim 6, wherein the outermost layer is smoothed by melting treatment of the molded container. 10. A blend in which the outermost layer contains a continuous phase (A) made of a propylene-based resin and a dispersed phase (B) made of an ethylene-based resin in a volume ratio of A: B = 90: 10 to 55:45. The multilayer packaging container according to claim 6, which is formed of: 11. The multi-layer packaging container according to claim 1, wherein the resin forming the outer layer and the inner layer or the outermost layer is made of thermoplastic polyester.