JPH0631875A - Multilayer plastic structure - Google Patents

Abstract

PURPOSE:To provide moldings having excellent function and appearance as a glossy shading plastic structure by successively laminating at least four layers of a polyester-based resin layer, an adhesive resin layer, a shielding resin layer and a shading resin layer. CONSTITUTION:A multilayer blow molding machine having four pieces of screw extruders is used. Noncrystalline polyester resin 1 is supplied to a screw A. Ethylene-alpha-olefine-maleic anhydride copolymer resin 2 is supplied to a screw B as an adhesive resin layer. High density polyethylene resin 3 having titanium white pigment is supplied to a screw C. High density polyethylene resin 4 containing carbon black is supplied to a screw E. These are plasticized and extruded. The same is successively laminated via a blow head and a laminated parison is formed and blow molding is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic structure having a multi-layer structure, and more specifically, a light-shielding multi-layer blow molding container, a multi-layer sheet, formed of a polyester resin and a polyolefin resin,
It is a multilayer structure such as a multilayer film and can be used for containers such as bottles and cups, and packaging materials.

[0002]

2. Description of the Related Art Conventionally, there are plastic containers having a light-shielding property, but in order to have a sufficient light-shielding property, it is unavoidable to use a highly light-absorbing pigment such as carbon black on the container wall. There is. Carbon black
Since it has a strong black color as is well known, it was difficult to manufacture a molded product colored with a light shade such as white, yellow, pink in a light shade and having a luster. .

For example, if a polyolefin resin which can be highly filled with carbon black is selected as a light-shielding substrate, a polyolefin resin-based hiding layer having adhesiveness with the light-shielding substrate must be applied as the outer hiding layer. There was a situation where there was no However, the present situation is that it is difficult to realize a non-black light-shielding plastic container having a sufficiently glossy feeling because polyolefin resins cannot have a high degree of gloss.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is a molded article having excellent performance and appearance as a glossy light-shielding plastic structure. Is provided.

[0005]

SUMMARY OF THE INVENTION The inventors of the present invention have conducted various studies and experiments in view of the above-mentioned drawbacks, for example, Japanese Patent Application No. 4-209.
As seen in No. 02, by inventing an adhesive resin of a polyester resin and a polyolefin resin, and further providing a resin layer having a concealing property as a layer to be an outer resin layer of the light-shielding resin layer, They have found that the drawbacks can be resolved, and have completed the present invention. The multi-layer plastic structure of the present invention is a multi-layer plastic structure having a resin structure in which at least four layers of a polyester resin layer, an adhesive resin layer, a masking resin layer, and a light-shielding resin layer are sequentially laminated. Instead of the polyester resin layer,
A polyamide resin, a saponified ethylene / vinyl acetate copolymer layer, a polycarbonate resin layer, etc. are used.

Further, in an embodiment of the present invention, the hiding resin layer is a mixture of a polyolefin resin and a hiding pigment, the hiding pigment is an inorganic or organic pigment, and the light blocking property of the light blocking resin layer. The pigment is carbon black or a pigment containing carbon black, the multilayer plastic structure has a single recycled material or a recycled material mixed layer, and the multilayer plastic structure has a glossy resin layer as an outer surface layer. For example, it is a multi-layer blow molded product.

The multi-layer plastic structure of the present invention may be a sheet-like product or a molded product thereof. Alternatively, the parison having these layer configurations may be laminated and extruded, and the container may be hollow blow-molded by using compressed air.

The present invention will be described in detail below with reference to the drawings. Fig. 1 shows the glossy plastic materials polyester resin, polyamide resin, ethylene
An outer resin layer (1) made of a saponified vinyl acetate copolymer or a polycarbonate resin layer, an adhesive resin layer (2), a hiding resin layer (3), and a light-shielding resin layer (4) were sequentially laminated. 1 shows a cross section of a multilayer plastic structure according to the invention. FIG. 2 shows a cross-sectional view when a single layer of recycled material or a layer (5) containing recycled material is applied to the outside of the light-shielding resin layer (4), and FIG.
A cross section of a multilayer plastic structure in which the recycled material alone or the layer (5) containing the recycled material is applied to the inside of the light-shielding resin layer (4) is shown.

The polyester resin used for the outer layer comprises a copolymer of polybasic acid and polyhydric alcohol. As such a polybasic acid, one containing terephthalic acid as a main component is preferable, and as a polyhydric alcohol, one containing ethylene glycol as a main component is preferable. The polybasic acid and the polyhydric alcohol may each include another polybasic acid and another polyhydric alcohol as a comonomer component.

Other polybasic acids that can be contained in the polybasic acid as a comonomer component include polybasic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid and diphenyletherdicarboxylic acid. .

Other polyhydric alcohols which can be contained as a comonomer component in the polyhydric alcohol include trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, diethylene glycol, 1,4
-A polyhydric alcohol component such as cyclohexane dimethylol can be used.

The polyamide resin used as the outer layer is preferably a material having low crystallinity or an amorphous transparent resin, for example, a copolymer of 6 nylon and 66 nylon, 6,10 nylon, aromatic nylon. Etc. can be used.

The saponified ethylene vinyl acetate copolymer has an ethylene content of 50 mol% or less and a saponification rate of 99.
% Or more of the copolymer can be used.

As the polycarbonate resin, a material generally used for blow molding may be used, but a resin for injection molding may have a molecular weight of about 15,000 or more.

The pigment contained in the concealing resin layer may be an ordinary inorganic pigment or an organic pigment alone or as a mixture, and examples of the inorganic pigment include oxides of titanium dioxide, nickel titanium yellow, red iron oxide, cobalt blue and the like, A hydroxide such as yellow iron oxide, a sulfide such as cadmium yellow, a silicate, and a ferrocyanide can be used. As the organic pigment, azo pigments such as azo lake, benzimidazolone and diarylide yellow, and polycyclic pigments such as quinacridone, isoindolinone and phthalocyanine can be used.

The pigment concentration used may be determined according to the layer thickness of the resin layer, the required hiding property, and the hue, and it is necessary to consider the relationship with the light-shielding resin layer located in the inner layer. Further, the pigment lightness needs to be higher than that of the light-shielding resin layer, and when it is lower than that of the light-shielding resin layer, the appearance may not be good.

The resin used for the hiding resin layer is
Polyolefin resin is preferred, high density polyethylene,
Polyethylene resin such as low density polyethylene and linear low density polyethylene, polypropylene resin such as homopolymer, random copolymer and block copolymer, and polyolefin resin such as polymethylpentene resin can be used.

Examples of the adhesive resin include glycidyl methacrylate resin, glycidyl group-containing resin such as ethylene / glycidyl metecrylate copolymer resin, ethylene / α-olefin copolymer, ethylene / α-olefin maleic anhydride copolymer and the like. Resins and mixtures of these resins,
Resins such as ethylene / maleic anhydride copolymer and propylene / maleic anhydride copolymer can be used.

The polyolefin resin layer used as the light-shielding resin layer may be a general resin, such as polyethylene resin, polypropylene resin, polymethylpentene resin or the like. As the light-shielding pigment, carbon black is particularly excellent in light-shielding properties, but other pigments such as iron black can be used depending on the required light-shielding properties.

When one layer of the recycled material of the multi-layered plastic structure is provided, the top flash and bottom flash generated during molding, defective molding products, etc. are crushed and the recycled material is crushed alone or mixed with virgin resin. It can be a layer. The recycled material layer can be provided between the adhesive resin and the light-shielding resin layer or as an inner layer of the light-shielding resin layer.

[0021]

The multilayer plastic structure of the present invention can prevent light from entering from the outside by providing one layer in the multilayer structure with a polyolefin layer containing a light-shielding pigment, and can be concealed as an outer layer. -Resistant polyolefin resin layer has a function of hiding the hue of the light-shielding pigment-containing resin layer and almost eliminating the influence of the color of the light-shielding resin layer on the appearance hue, and the outermost polyester resin layer, polyamide resin, Saponified ethylene / vinyl acetate copolymer,
Alternatively, the polycarbonate resin layer provides a glossy, multi-layered plastic structure.

[0022]

【Example】

<Example 1> Using a multi-layer blow molding machine having four screw extruders, a screw A was made of a non-crystalline polyester resin, and a screw B was made of ethylene / α-olefin / maleic anhydride as an adhesive resin layer. Copolymer resin, screw C is supplied with high-density polyethylene resin containing 2.5% of titanium white pigment, screw E is supplied with high-density polyethylene resin containing 2 wt% of carbon black, and plasticized and extruded under the following conditions. Then, an amorphous polyester resin, an adhesive resin, and a high-density polyethylene resin are sequentially laminated from the outer layer surface through a blow head to form a laminated parison, and the parison is formed in a blow mold having a cylindrical bottle-shaped cavity. After scissors and cutting the upper part of the parison, blow molding was performed using compressed air. The obtained bottle had a white glossy appearance, had a property of not transmitting external light to the inside of the bottle, and had other physical properties without problems. The average thickness of the bottle body was 0.1 mm for the polyester resin layer, 0.15 mm for the adhesive resin layer, 0.6 mm for the hiding resin layer, and 0.15 mm for the light-shielding polyethylene resin layer.

Screw diameter Barrel temperature Screw A 30 mmφ 200 ° C. Screw B 25 mmφ 200 ° C. Screw C 50 mmφ 190 ° C. Screw E 30 mmφ 190 ° C.

Example 2 A multi-layer blow molding machine having four screw extruders was used. Amorphous aromatic polyamide resin was used for screw A and ethylene / maleic anhydride copolymer resin was used for screw B as an adhesive layer. , Screw C
The hiding polyethylene resin used in Example 1 and the light-shielding resin used in Example 1 were supplied to the screw E, and a cylindrical container was molded by the same method as described in Example 1. The bottle container has a polyamide resin layer of 0.1 mm and an adhesive resin layer of 0.
The container had an average wall thickness of 15 mm, a hiding resin layer 0.55 mm, and a light-shielding polyethylene resin layer 0.2 mm, and had glossiness and light-shielding appearance, and there was no problem in physical properties.

Example 3 A multi-layer blow molding machine having five screw extruders was used, the polyester resin used in Example 1 was used for screw A, and the adhesive resin used in Example 1 was used for screw B. The screw C was supplied with the concealing resin used in Example 1, the screw D was supplied with high-density polyethylene, and a resin obtained by mixing a recycled scrap material of the multilayer plastic according to this example in a weight ratio of 30:70. Is supplied with a high-density polyethylene resin containing 2 wt% of carbon black, and is plasticized and extruded under the following temperature conditions to form a laminated parison via a blow head. A polyester resin layer is sequentially formed from the parison outer surface layer,
A parison having a five-layer structure of an adhesive resin layer, a hiding resin layer, a recycling layer, and a light shielding resin layer was extruded. The parison was sandwiched in a blow molding die having a flat bottle-shaped cavity, the upper part of the parison was cut, and then blow molding was performed using compressed air.

Screw diameter Barrel temperature Screw A 30 mmφ 200 ° C. Screw B 25 mmφ 200 ° C. Screw C 50 mmφ 190 ° C. Screw D 50 mmφ 200 ° C. Screw E 30 mmφ 190 ° C.

The obtained bottle has a polyester resin layer /
Adhesive resin layer / concealing resin layer / recycle layer / light-shielding resin layer = 0.7 / 0.6 / 4 / 3.3 / 1.4 and the average total thickness is 1.0 mm. The container was excellent in terms of glossiness, appearance hue, and light-shielding property.

Example 4 Using a multi-layer sheet extruder having four screw extruders, a screw F was saponified with ethylene / vinyl acetate copolymer, and a screw G was an anhydrous polypropylene resin as an adhesive resin. Modified maleic acid, H-concealing polypropylene resin containing 2.5 wt% titanium white in screw H, polypropylene resin containing 1.5 wt% carbon black in screw J, polypropylene containing 2.5 wt% titanium white in screw K A resin was supplied and plasticized and extruded under the following conditions, the layers were joined in a manifold, and a sheet having a thickness of 2.5 mm was extruded. After cutting the sheet to a predetermined size, reheating,
Vacuum molding was carried out in a cup-shaped vacuum molding die to obtain a molded product.

The outer surface of the cup has a glossy ethylene
Made of vinyl acetate copolymer saponified resin, inner layer has white polypropylene resin layer, ethylene / vinyl acetate copolymer saponified resin layer / adhesive resin layer / hiding resin layer / light shielding resin layer / white polypropylene Resin layer = 1/1/3/2/3, the average total thickness was 0.9 mm, and the container had good gloss, appearance hue, and light-shielding properties.

Screw diameter Barrel temperature Screw F 40 mmφ 210 ° C. Screw G 40 mmφ 220 ° C. Screw H 60 mmφ 220 ° C. Screw J 60 mmφ 220 ° C. Screw K 60 mmφ 220 ° C.

Comparative Example 1 Using a multi-layer blow molding machine having three screw extruders, screw A contains a high-density polyethylene resin containing 3 wt% of titanium white, and screw B contains 2.5 wt% of carbon black. The same resin as the screw A was supplied to the high density polyethylene resin and the screw C, and a cylindrical bottle was molded under the following plasticization conditions. The obtained bottle had a white hue and had no problem in terms of physical properties, but it was a bottle having no appearance gloss. The container had the following layer thickness ratio, polyethylene resin layer / light-shielding resin layer / polyethylene resin layer = 4/2/4, and the average thickness was 1.0 mm.

Screw diameter Barrel temperature Screw A 30 mmφ 200 ° C. Screw B 25 mmφ 200 ° C. Screw C 30 mmφ 200 ° C.

<Comparative Example 2> Using the multi-layer blow molding machine used in Comparative Example 1, a high-density polyethylene resin containing 3 wt% of titanium white was supplied to the screws A, B, and C under the same conditions as in Comparative Example 1. A cylindrical bottle was formed by the method. The physical properties of the obtained bottles and cup containers are shown below.

<Physical Properties Table> Outer layer glossiness Color difference Light transmittance Drop intensity (%) (Number of cracks) Example 1 95 1.8 0 0 Example 2 92 1.7 0 0 Example 3 95 1.7 0 0 Example 4 95 1.7 0 0 Comparative Example 1 13 1.8 0 0 Comparative Example 2 13 0 20 0 Note) Color difference is a hue difference when Comparative Example 2 is used as standard. Drop strength is n = 10, 1.2 m. Drop 5 ℃

[0035]

According to the method of the present invention, a light-shielding plastic structure having a good appearance gloss and capable of being colored in various hues can be obtained, and a container having a good appearance and having a function of protecting the contents from light, etc. A molded product of is obtained.

[0036]

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional explanatory view of a multilayer plastic structure showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view of a multilayer plastic structure showing one embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional explanatory view of a multilayer plastic structure showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer layer resin layer 2 ... Adhesive resin layer 3 ... Concealment resin layer 4 ... Light-shielding resin layer 5 ... Recycled material simple substance or a layer containing recycled material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location B32B 27/36 102 7258-4F (72) Inventor Yusuke Terauchi 1-5-1 Taito, Taito-ku, Tokyo No. Toppan Printing Co., Ltd. (72) Inventor Shunichi Kato 1-5-1 Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd.

Claims (10)

[Claims] 1. A multi-layer plastic structure having a resin structure in which at least four layers of a polyester resin layer, an adhesive resin layer, a masking resin layer, and a light shielding resin layer are sequentially laminated. 2. A multi-layer plastic structure having a resin structure in which at least four layers of a polyamide resin layer, an adhesive resin layer, a hiding resin layer, and a light shielding resin layer are sequentially laminated. 3. A multi-layer plastic structure comprising a resin structure in which at least four layers of a saponified ethylene / vinyl acetate copolymer layer, an adhesive resin layer, a hiding resin layer, and a light shielding resin layer are sequentially laminated. 4. A polycarbonate resin layer, an adhesive resin layer,
A multi-layer plastic structure having a resin structure in which at least four layers of a hiding resin layer and a light shielding resin layer are sequentially laminated. 5. A multilayer plastic structure according to any one of claims 1 to 4, wherein the hiding resin layer is a mixture of a polyolefin resin and an inorganic or organic pigment. 6. A multi-layer plastic structure according to claim 1, wherein the light-shielding resin layer is carbon black alone or a mixture of a pigment mainly composed of carbon black and a polyolefin resin. . 7. The recycled material of the multilayer plastic structure as a single material or recycled material according to claim 1 or 6, between the light-shielding resin layer and the hiding resin layer or on the side of the light-shielding resin layer opposite to the adhesive resin layer. A multi-layer plastic structure having a composition of at least 5 layers, characterized in that it has a mixture layer. 8. The multilayer structure according to claim 1, wherein the polyester resin layer, the polyamide resin layer, the ethylene / vinyl acetate copolymer layer, and the polycarbonate resin layer contain a transparent or opaque pigment. Plastic structure. 9. The multilayer plastic structure according to claim 1, wherein the light-shielding resin layer has a higher lightness than the light-shielding resin layer or the recycling layer. 10. In the multilayer plastic structure,
The multilayer plastic structure according to any one of claims 1 to 8, which is a multilayer blow-molded article in which the inner layer is a light-shielding resin layer.