JPH0538787A - Multilayer plastic vessel having excellent surface glossiness - Google Patents

Abstract

PURPOSE:To provide a multilayer plastic vessel having the texture of ceramics, etc., which have fine appearance, are colored and have excellent surface glossiness, while also being superior on sanitariness. CONSTITUTION:A glossy resin layer 8 having a light transmittance of 90% or more in thickness of 100mum and a 60 deg. specular gloss of 80% or more is formed as an outer surface layer, and a precolored resin layer 9 colored by adding a colorant to a polyolefin resin is formed on the inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered plastic container having excellent surface gloss, and more particularly to a multi-layered plastic container having a beautiful appearance and being colored and having a surface-glossy ceramic-like texture. It is a thing.

[0002]

2. Description of the Related Art It is well known that a plastic hollow molded container has a multi-layered laminated structure. In this case, the inner and outer surface layers of the container are polyethylene, polypropylene, etc. and polyolefin from the viewpoint of hygienic properties and moisture resistance. A resin is used, and from the viewpoint of the gas barrier of the container, a laminated structure in which a gas barrier resin such as an ethylene / vinyl alcohol copolymer is sandwiched between these two surface layers is adopted.

As a polyolefin resin for blow molding, grades different from those used for ordinary molding are generally used. That is, during blow molding, a phenomenon in which the molten parison hangs down due to its own weight (called drawdown) or a phenomenon in which the molten parison itself becomes wavy or causes shark skin (melt fracture) is likely to occur. , Melt flow rate (MFR) is 2.
A resin having a wide molecular weight distribution defined by the ratio of the weight average molecular weight to the number average molecular weight of 0 g / 10 minutes or less and the weight average molecular weight / number average molecular weight, that is, 3.5 to 7 is used. .. Although this resin is effective in preventing the drawdown and melt fracture, the surface of the vessel wall formed is poor in gloss and lacks transparency.
Further, in the case of a bottled product, the appearance of the content through the bottle is inferior to the actual product, and the product value is poor, and the glossiness is about 60% at most.

The inventors of the present invention have proposed a multi-layer plastic container which solves the above problems and is excellent in surface gloss. (JP-A-2-215529) This is a multilayer plastic container having a structure in which two or more types of resin layers are laminated, and the outermost surface layer has an ethylene content of 2
~ 8 wt%, melt flow rate 2.5 g / 10
It is formed from an ethylene / propylene / random copolymer having a ratio of weight average molecular weight / number average molecular weight of 3 to 5 or more and having an excellent surface gloss and a gloss (according to JIS K 7105). Compliance, incident angle 60 °) is 85
%, And a surface gloss similar to that obtained with a polycarbonate or polyester bottle.

Generally, a plastic container is lightweight and
It is widely used in place of glass containers, porcelain containers, etc. because it is resistant to shocks and is easy to handle, but in terms of aesthetic appearance and elegance. The reality is that these containers are not reached. For this reason, for example, containers such as cosmetics that value the image of the product so as to enhance the product value and motivate consumers to purchase, and containers for high-grade contents, are mainly made of glass, ceramics, etc. Is used.

[0006]

The above-mentioned multilayer plastic container having excellent surface gloss is also excellent in surface gloss, but the texture of a glass container or a ceramic container is not obtained.

An object of the present invention is to provide a multi-layer plastic container which has a beautiful appearance, is colored, has the texture of ceramics excellent in surface gloss, and is hygienic.

[0008]

According to the present invention, there is provided a multi-layer plastic container having a structure in which at least two kinds of resin layers are laminated, the outer surface layer having a thickness of 100 μm.
A light transmittance of 90% or more at m and a glossy resin layer having a 60-degree specular glossiness (according to JIS K 7105) of 80% or more are provided, and coloring is performed by adding a coloring agent to a polyolefin resin inside. There is provided a multi-layered plastic container having excellent surface gloss, which is provided with the colored resin layer.

The glossy resin layer of the outer surface layer is selected from polycarbonate, saturated polyester, polyamide, aromatic polyamide, ethylene / vinyl alcohol copolymer, acrylic ester resin, acrylonitrile resin, styrene resin and polyarylate. It is preferably composed of at least one resin.

The polyolefin resin for the inner colored resin layer is at least one resin selected from polypropylene, a propylene / olefin copolymer having an olefin content other than propylene of 1 to 10% by weight, and high density polyethylene. Preferably consisting of

[0011]

In FIG. 1 showing an example of the multi-layer plastic container of the present invention, the container 1 is connected to a body 2, a lower end of the body 2, and a bottom 3 formed by pinch-off of a parison and an upper end of the body 2. A neck portion 5 which is continuous with a shoulder portion 4 through which a mouth portion 6 is sealingly engaged with a lid (not shown), and a screw and a bead below the mouth portion 6. ,
A lid mounting portion 7 including a flange or shoulders is provided.

As shown in the other specific examples of FIG. 2 and FIG. 3 to FIG. 5, which shows an enlarged sectional view (II in FIG. 1) of the container wall of this multilayer plastic container, the laminated structure of the container wall has an outer surface layer. It has a glossy resin layer 8 and a colored resin layer 9 inside thereof. The glossy resin layer 8 and the colored resin layer 9 are adhered by an adhesive layer 10 interposed therebetween. 2 to FIG. 5, FIG. 2 shows the most basic configuration.

The multi-layered plastic container of the present invention has 1) an outer surface layer having a light transmittance of 90% or more at a thickness of 100 μm and a 60-degree specular gloss (JIS K 71).
(According to No. 05) is provided with a glossy resin layer of 80% or more, and 2) a colored resin layer colored by adding a coloring agent to a polyolefin resin is provided inside.

The light transmittance in the present invention means the transmittance of visible light (wavelength 380 to 780 nm), and the test method is according to JIS K 7105. The 60-degree specular glossiness (%) is measured according to JIS K 7105 at an incident angle of 60 degrees and is represented by the following formula. 60 degree specular gloss (%) = (ψ _s / ψ ₀ ) × 100: In the formula, ψ _s and ψ ₀ are specular reflection light fluxes from the sample surface and the reference surface (glass surface having a refractive index of 1.567), respectively. ..

Since the glossy resin layer forms the outer surface layer and the light transmittance at a thickness of 100 μm is 90% or more, this layer is excellent in transparency and also has a 60-degree specular gloss (JIS K).
7105) is 80% or more, so that the surface gloss is excellent. The excellent transparency and surface gloss of this layer
When the outer appearance of the container, the colored tone of the inner colored resin layer, the skin surface and the like can be seen with a deep luster, giving a beautiful and elegant ceramic-like texture.

The colored resin layer is made of various kinds of colorants and fillers,
Coloring degree, color tone, etc. can be variously changed depending on the amount used, and transparent to opaque ones can be obtained. Furthermore, not only a single color tone but also complex colors such as white magnetic tone, pearl tone, marble tone etc. It is possible to bring out a unique color tone and skin surface. Since such a color tone and skin surface are integrally covered with the glossy resin layer, it can be viewed with a deep gloss. Further, the multi-layer plastic container of the present invention is capable of producing a glass-like texture having a transparency such that the amount of the contents can be understood by adjusting the color tone and transparency of the colored resin layer or the like even in the case of a ceramic-like texture. Furthermore, it is possible to prevent the contents from affecting the light.

It is desirable that the glossy resin layer has a light transmittance of 90% or more, preferably 95% or more at a thickness of 100 μm, and a 60-degree specular gloss (JIS K 710).
5) is 80% or more, preferably 90% or more. When the light transmittance is less than 90%, the transparency tends to decrease and the deep glossiness cannot be exhibited, and when the 60 degree specular glossiness is less than 80%, the surface glossiness is insufficient. It tends to lose its deep gloss. The characteristics of both can be combined to provide a deep surface gloss, and match the colored resin layer to give a ceramic-like texture.

As the glossy resin of the glossy resin layer of the present invention, those having the above-mentioned characteristics must be selected. These are preferably polycarbonate, saturated polyester,
It is composed of at least one resin selected from polyamide, aromatic polyamide, ethylene / vinyl alcohol copolymer, acrylic ester resin, acrylonitrile resin, styrene resin, and polyarylate. Also used in the form of more than layers. The thickness of the glossy resin layer is usually 20 μm to 200 μm, preferably 3
It is used in the range of 0 μm to 150 μm.

The polyolefin resin used for the colored resin layer or the like must be capable of preventing drawdown and melt fracture. High density polyethylene, polypropylene,
Polyolefin copolymers containing propylene as a main component are used, and these are chemically stable even when they come into contact with the contents, which makes the container excellent in hygiene.

[Preferred Embodiment] The resin of the glossy resin layer of the outer surface layer used in the present invention is polycarbonate,
At least one thermoplastic resin selected from saturated polyester, aliphatic polyamide, aromatic polyamide, ethylene / vinyl alcohol copolymer, acrylic ester resin, acrylonitrile resin, styrene resin, and polyarylate is used. ..

When these resins are used as the glossy resin layer of the outer surface layer of the container, they must have a thickness of 100 μm and a light transmittance of 90% or more, and a 60 ° specular gloss of 80% or more. Is.

As the polyolefin resin for the colored resin layer, use is made of high density polyethylene, polypropylene, propylene / olefin copolymer having an olefin content other than propylene of 15 mol% or less and propylene of 85 mol% or more. You can The high density polyethylene should have a melt flow rate (MFR) of 0.5 g / 10 min or less in terms of preventing drawdown. Polypropylene, propylene / olefin copolymer and the like may be used alone or as a blend, but the melt flow rate (MFR) should be 2 g / 10 minutes or less.

For a polyolefin resin such as a colored resin layer,
A scrap resin (of the multilayer plastic container of the present invention) can also be mixed and used with a colorant.

As the colorant to be contained in the polyolefin resin (including scrap resin) of the colored resin layer,
Known inorganic or organic pigments, dyes, etc. may be used alone or in combination of two or more. Functional pigments are also used. Further, an extender pigment, a filler, a dispersant and the like can be used together with these. Some examples of pigments, dyes and the like, furnace black, carbon black such as channel black, titanium oxide such as rutile-type anatase type, titanium yellow, phthalocyanine blue, phthalocyanine green, benzidine yellow, quinacridone pigment, rouge, quinoline yellow, Metal powder, pearl pigment, fluorescent pigment, etc. can be mentioned.

The thickness of the colored resin layer is 50% or more of the total thickness of the glossy resin layer and the colored resin layer. or,
In addition to the above in the glossy resin layer and the colored resin layer described above,
Antiaging agents, antioxidants, light stabilizers and the like can be appropriately added.

As the adhesive used for the adhesive layer between the glossy resin layer and the colored resin layer, ethylene / vinyl acetate copolymer (EVA), ethylene / acrylic acid ester (E)
EA) and the like, blends of these with rubber, polyamide-based adhesives, acid-modified polyolefin resins, polyester-based adhesives and the like are used.

When a gas barrier layer is provided on the multilayer plastic container of the present invention as described below, ethylene / vinyl alcohol copolymer, aliphatic polyamide, aromatic polyamide, etc. are used as the gas barrier resin of the gas barrier layer. The barrier resin can be used. When a gas barrier layer is provided, an adhesive layer is provided,
An adhesive similar to that described above is used.

The layer structure of the container wall of the multi-layer plastic container of the present invention is as shown in FIGS. The most basic configuration is as shown in FIG. 2, and this configuration is mainly used. In FIG. 2, the glossy resin layer 8 of the outer surface layer is bonded and integrated with the inner colored resin layer 9 via the adhesive layer 10 to form a container wall. FIG. 3 shows another example, in which a polyolefin resin layer 11 is provided inside the colored resin layer 9.
With this configuration, a scrap resin can be mixed in the colored resin layer 9 together with the colorant for use. FIG. 4 shows another example, in which a resin layer 12 other than a polyolefin resin such as a saturated polyester or polyamide is provided inside the colored resin layer 9, for example, a thermoplastic resin other than a polyolefin resin.
In this case, the adhesive layer 13 is provided between the colored resin layer 9 and the inner surface resin layer other than the polyolefin resin.
Also in this structure, the scrap resin can be mixed in the colored resin layer 9 together with the coloring agent for use. FIG. 5 shows another example, in which a gas barrier layer is provided. The gas barrier layer 14 is provided inside the colored resin layer 9 via the adhesive layer 15a, and the polyolefin resin layer 11 is provided inside the gas barrier layer 14 via the adhesive layer 15b. In FIG. 5, the polyolefin resin layer 1
Instead of 1, the resin layer 12 other than the polyolefin resin can be provided. Further, a scrap resin can be mixed in the colored resin layer 9 together with the colorant for use. The laminated structure of the resin of the container wall is not limited to the above-mentioned laminated structure as long as it has the above-mentioned characteristics, and it is needless to say that various modifications can be made.

The multi-layer plastic container of the present invention has a wall thickness of 0.3 to 1.5 mm, especially 0.5 to 1.2 m.
It is preferable to set it so that the range is about m. Although the individual layer thickness of the layer structure of the container wall is not specified separately, the ratio of the thickness of the glossy resin layer of the outer surface layer to the thickness of the inner colored resin layer is as described above. Occupy 50% or more of the sum of the thickness of the resin layer and the thickness of the colored resin layer,
That is, it is necessary to have a thickness equal to or larger than the thickness of the glossy resin layer.

Manufacture of Multi-Layer Plastic Containers The multi-layer plastic container of the present invention can be made by co-extruding a multi-layer parison and then blow-molding the multi-layer parison. When producing a multi-layer parison by coextrusion molding, it is important that the colored resin of the colored resin layer is melt-kneaded through at least a kneading type screw. This melt-kneading can be carried out sufficiently to uniformly and evenly mix it, or the kneading can be carried out by adjusting it without being sufficiently kneaded to form a pattern on the colored resin. Further, it is necessary to suppress the fluctuation of the extrusion rate of the extruder within plus or minus 3%. In the present invention, by performing melt extrusion of the colored resin layer by using an extruder equipped with a kneading type screw such as a dullage type screw and a pinning screw,
It is possible to prevent the variation of the extrusion rate, and to manufacture a hollow molded container having a uniform layer thickness and excellent flatness. Besides using the kneading type screw described above,
Polishing the die surface at least near the outlet is also extremely important for preventing the occurrence of die lines.

[0031]

The multilayer plastic container of the present invention has an outer surface layer having a light transmittance of 90 at 100 μm in thickness.
%, The glossy resin layer has a specular gloss of 60% or more and a surface glossiness of 80% or more, and a container wall having a layer structure in which a colored resin layer obtained by adding a coloring agent to a polyolefin resin is provided inside thereof. In appearance, the colored resin layer is seen through the glossy resin layer, has a deep surface gloss, and has a ceramic-like texture. Therefore, in addition to the conventional fields, the container of the present invention has new fields, cosmetics such as creams, lotions and hair tonics, fields of containers such as cosmetics such as shampoos, conditioners, conditioners, etc. It is suitable for containers that value the image of an inviting product. In addition, it is also suitable as a container for high-grade products.

[0032]

EXAMPLES The present invention will be described with reference to examples. Example 1 As the glossy resin layer of the outer surface layer, a polycarbonate having a light transmittance of 100 μm of 95% and a specular gloss of 60 degrees of 90% was supplied to the extruder for the outer layer, and as a colored resin layer of the inner surface layer, 2% by weight of titanium oxide and 0.05% by weight of phthalocyanine blue in an ethylene / propylene / random copolymer having an MFR of 1.5 g / 10 minutes, a weight average molecular weight / number average molecular weight of 5.5, and an ethylene content of 4% by weight. % Of the colored resin is melt-kneaded by a kneading screw and supplied to the extruder for the inner layer, and the ethylene / vinyl acetate copolymer hot melt adhesive as the adhesive layer is supplied to the extruder for the adhesive layer, and FIG. A molten three-layer parison having the layer structure shown in (1) was extruded, and this parison was blow-molded in a blow mold to obtain a multilayer plastic container as shown in FIG. The capacity, wall thickness, layer structure, etc. are as follows. Volume 500ml Body thickness 0.8mm Layer composition Gloss resin layer 80μm Adhesive layer 20μm Colored resin layer 700μm The appearance of this container is beautiful, it has excellent surface gloss, and it is a slightly bluish white-based ceramic texture. Had.

Example 2 As the glossy resin layer of the outer surface layer, the light transmittance was 90.
%, 60-degree specular gloss 90% saturated polyester resin PET-G (trade name, polyester copolymer manufactured by Eastman Chemical Co., Ltd.) was supplied to the extruder for the outer layer, and the MFR as the colored resin layer of the inner surface layer was 0. For high density polyethylene (density 0.955 g / cm ³ ) of ³ g / 10 min, a coloring resin obtained by adding 0.5% by weight of titanium oxide and 2% by weight of pink fluorescent pigment is melt-kneaded with a kneading type screw and used for the inner surface layer. It is supplied to an extruder, and an ethylene / vinyl acetate copolymer hot melt adhesive is supplied as an intermediate adhesive layer to the adhesive layer extruder to extrude a molten multilayer parison having the layer structure shown in FIG. Was blow-molded in a blow mold to obtain a bottle having an average wall thickness of 1 mm and an internal volume of 300 ml as shown in FIG. The layer structure of the body thickness of this bottle is as follows. Outer surface layer (glossy resin layer) 50 μm Middle layer (adhesive layer) 20 μm Inner surface layer (colored resin layer) 930 μm The appearance of this container has a pale pink ceramic-like texture.

Example 3 The same saturated polyester resin PET-G as that used in Example 2 was fed to the outer layer extruder as the glossy resin layer of the outer surface layer, and in Example 2 as the colored resin layer of the inner surface layer. 70% by weight of high density polyethylene similar to that used, Example 2
0.5% by weight of titanium oxide and 2% by weight of pink fluorescent pigment were added to a mixture of 30% by weight of crushed scrap resin, and the mixture was melted and kneaded with a full flight type screw. To the extruder for the inner surface layer and used as an adhesive layer for the intermediate layer in the same manner as in Example 2.
The vinyl acetate copolymer-based hot melt adhesive was fed to the adhesive layer extruder to extrude the molten multi-layer parison in the same manner as in Example 2, and this parison was blow-molded in a blow mold to obtain the average meat of the body. The thickness, the internal volume, and the thickness of the body were the same as in Example 2, and a very beautiful pinkish marble-like container having a light appearance was obtained. In this marbled pattern, since the colored resin constituting the colored resin layer was not kneaded until it became uniform by adjusting the kneading, a pattern was formed and the pattern was present in an appropriately dispersed state, and the refractive index was different. Thought to be a thing.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an example of a multilayer plastic container of the present invention.

FIG. 2 is an enlarged cross-sectional view of a container wall (II portion) of the multilayer plastic container of FIG.

FIG. 3 is an enlarged cross-sectional view of a container wall of another example of the multilayer plastic container of the present invention.

FIG. 4 is an enlarged cross-sectional view of a container wall of another example of the multilayer plastic container of the present invention.

FIG. 5 is an enlarged sectional view of a container wall of another example of the multilayer plastic container of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Body part 3 Bottom part 4 Shoulder part 5 Mouth neck part 6 Mouth part 7 Lid mounting part 8 Gloss resin layer (outer surface layer) 9 Colored resin layer 10 Adhesive layer 11 Polyolefin resin layer 12 Other than polyolefin resin Resin layer 13 Adhesive layer 14 Gas barrier layer 15a, 15b Adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B65D 1/09 1/02 Z 7445-3E

Claims (3)

[Claims] 1. A multi-layer plastic container having a structure in which at least two or more resin layers are laminated, wherein the outer surface layer has a light transmittance of 9 at a thickness of 100 μm.
0% or more, 60 degree specular gloss (JIS K 7105
Of 80% or more), and a colored resin layer colored by adding a coloring agent to a polyolefin resin is provided on the inner side of the multilayer resin layer having excellent surface gloss. Plastic container. 2. The glossy resin layer of the outer surface layer is formed of polycarbonate, saturated polyester, polyamide, aromatic polyamide, ethylene / vinyl alcohol copolymer, acrylic ester resin, acrylonitrile resin, styrene resin, polyarylate. The multi-layer plastic container according to claim 1, which is made of at least one resin selected from the group consisting of: 3. The polyolefin resin of the colored resin layer,
The multi-layer plastic container according to claim 1, comprising at least one resin selected from polypropylene, a propylene / olefin copolymer having an olefin content other than propylene of 1 to 10% by weight, and high density polyethylene. ..