JP3047730B2 - Multi-layer plastic container with label - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic plastic container, and more particularly to a multi-layer plastic container with an in-mold method having excellent gloss and surface properties.

[0002]

2. Description of the Related Art Heretofore, containers made of a single polyolefin resin such as polypropylene have been widely used from the viewpoints of sanitary properties, moisture resistance, excellent physical properties such as excellent chemical resistance, and price. However, these containers have conventionally been pointed out as having a problem of poor gloss and surface properties in appearance. Although a labeled plastic container already exists, there is only a plastic container having a greatly different gloss level between the label and the container main body, and a highly glossy labeled container having a truly integrated feeling as a high-gloss container has not been developed.

As a countermeasure, there is a method in which a container is formed into a multilayer structure and a resin having good gloss and surface properties, for example, a polypropylene homopolymer, an ethylene-propylene random copolymer, or the like is used as an outer layer. In the case of using an ethylene-propylene random copolymer, in one case, ethylene is contained in an amount of 3 to 8% by weight.
Conventionally, there is a container in which an ethylene-propylene random copolymer having an MFR of about 2.5 is disposed in the outer layer, but even in such a container, when a container with a label by the inmold method is used, In particular, the impact strength at the time of dropping at a low temperature and the surface glossiness were not sufficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and has properties such as sanitary properties, moisture resistance, and excellent chemical resistance. An object of the present invention is to provide an in-mold type labeled plastic container having excellent surface gloss and surface properties while maintaining the impact strength of the container due to dropping or the like.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a multi-layer plastic container with a label by an in-mold method in which a label and a container are integrated by molding after inserting a label in a mold in advance. In the multilayer plastic container, a polypropylene random copolymer resin is used for the outermost layer and one or more polyolefin resin layers are provided inside the outermost layer, and the polypropylene random copolymer resin used for the outermost layer is 0.5 to 2. 2.0 to 15.0% by weight of a polyethylene resin containing 0% by weight of ethylene and having a density of 0.94 g / cm ³ or less, and 500% of a nucleating agent.
Resin having a melt flow rate (JIS-K6758, hereinafter referred to as MFR, unit: g / 10 minutes) of 40.0 or less to which the ethylene / α-olefin copolymer resin is added in an amount of 2.0 to 30.0% by weight. And the label has a glossiness, and a difference in glossiness between the resin surface of the multilayer plastic container and the label is 30.
% Is a labeled plastic container. In addition, after inserting the label in the mold in advance, in a multi-layer plastic container with a label by the in-mold method in which the label and the container are integrated by molding, a polypropylene random copolymer resin is used for the outermost layer, and a polyolefin resin is used for the inside. A multilayer plastic container provided with at least one layer, wherein the polypropylene random copolymer resin used for the outermost layer contains 0.5 to 2.0% by weight of ethylene and has a density of 0.94 g / cm ³ or less. 2.0 to 15.0% by weight of a polyethylene resin, and 500 to 300% of a nucleating agent.
0 ppm, a multi-layer plastic container having a MFR of 40.0 or less to which a propylene / α-olefin copolymer resin is added in an amount of 2.0 to 30.0% by weight, and wherein the label has glossiness, This is a labeled plastic container in which a difference in glossiness from the resin surface of the multilayer plastic container is within 30%.

As an embodiment, in the multilayer plastic container according to any one of the above, at least two layers obtained by adding a recycled material comprising the present multilayer plastic container to the innermost layer.
Labeled multilayer plastic container having a layer configuration of at least three layers, or in the multilayer plastic container according to any of the above, at least three or more layers obtained by adding a recycled material comprising the multilayer plastic container to the second layer from the innermost layer And a labeled multi-layer plastic container having the following layer structure.

The multilayer plastic container of the present invention is a multilayer blow-molded container, a multilayer injection-molded container, a multi-layer sheet-shaped cup, and other containers made by forming a parison by laminating extrusion and blowing compressed air into the parison. Or it may be a packaging material.

[0008] In order to decorate the multilayer plastic container of the present invention, a label having a gloss difference of 30% or less compared to the plastic container body is inserted into a mold in advance and then molded to give a glossy feeling. Since there is no step between the label and the plastic portion, a labeled plastic container having a sense of unity between the two can be obtained.

Hereinafter, the present invention will be described in detail. As the nucleating agent used for the outermost layer, a fatty acid metal salt, a benzylidene sorbitol compound, a metal organic phosphate, or the like can be used.

Examples of the polyolefin resin used for the inner layer include polypropylene resins such as block copolymers and random copolymers, and polyethylene resins belonging to a density range of about 0.85 to 0.97, for example, ultra-low density, low density,
It is possible to use a linear low-density or high-density polyethylene resin alone, a mixture of these resins, or a mixture of these resins with another polyolefin resin.

As a method of reducing the recycled material obtained by pulverizing the top flash and the bottom flash generated at the time of molding the present plastic container into the present plastic container, the innermost layer or the outer layer thereof may be a single recycled material or It can be mixed with a polypropylene resin such as a block copolymer or a random copolymer, or a polyethylene resin belonging to a density range of about 0.85 to 0.97.

[0012]

The multilayer plastic container of the present invention has a hygienic feature.
While maintaining content resistance such as heat resistance, moisture resistance, and excellent chemical resistance.
The outermost layer in the multilayer structure has a polypropylene random
The polymer contains 0.5 to 2.0% by weight of ethylene
And the density is 0.94 g / cm ^ThreeThe following polyethylene resin
2.0 to 15.0% by weight, and a nucleating agent of 500 to 300
0 ppm, ethylene / α-olefin copolymer resin
Melt flow rate added 2.0 to 30.0% by weight
(JIS-K6758, hereinafter referred to as MFR, unit g / 1
0 min) is 40.0 or less, or the ethylene /
Instead of the α-olefin copolymer resin, propylene /
Using a resin composition to which an α-olefin copolymer resin is added
That the container falls due to the in-mold method
Excellent surface gloss and surface properties while maintaining impact strength due to
Make it possible to obtain labeled plastic containers
You. In addition, by being integrally molded with a glossy label,
A plastic container with further enhanced gloss is obtained. Change
The difference between the container body and the label should be within 30%
Thus, a unified view of gloss can be created.

[0013]

【Example】

<Example 1> Using a multilayer blow molding machine having two screw extruders as described below, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. Was previously inserted into the correct position with a glossy label by an insertion machine and held by suction.
After sandwiching in a blow mold having a flat bottle-shaped cavity with a capacity of 00 ml and cutting the upper part of the parison, blow molding was performed using compressed air.

Screw diameter Temperature Molded product layer ratio Screw A 25 mmφ 210 ° C. 10% Screw B 50 mmφ 210 ° C. 90% Die head ２１０ 210 ° C.

Resin Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene and having a density of 0.87
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, ethylene / α-olefin copolymer resin
0 wt% added melt flow rate (JIS-K67
58, hereinafter referred to as MFR, unit g / 10 min) is 10.0
Screw copolymer B: ethylene-propylene block copolymer resin with MFR of 0.5

Labels used The outer layer surface was subjected to back printing using CPP, and the surface was coated with aluminum and further coated with a heat sealant.
High gloss label with%.

Example 2 Using a multilayer blow molding machine having the following two screw extruders, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. The parison was previously inserted into a blow mold having a flat bottle-shaped cavity with a capacity of 800 ml, in which a glossy label was previously inserted into a correct position by an inserter and held by suction, and after cutting the upper part of the parison, compressed air was discharged. Was used to perform blow molding.

Screw diameter Temperature Molded product layer ratio Screw A 25 mmφ 210 ° C. 10% Screw B 50 mmφ 210 ° C. 90% Die head {210 ° C.}

Resin Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene was added with a density of 0.87%.
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, a polypropylene random copolymer resin having an MFR of 10.0 to which 5.0% by weight of a propylene / α-olefin copolymer resin was added. Screw B: an ethylene-propylene block copolymer resin having an MFR of 0.5

Labels used The outer layer surface was backprinted using CPP, and the surface was coated with aluminum and further coated with a heat sealant.
High gloss label with%.

Example 3 Using a multilayer blow molding machine having the following two screw extruders, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. The parison was previously inserted into a blow mold having a flat bottle-shaped cavity with a capacity of 800 ml, in which a glossy label was previously inserted into a correct position by an inserter and held by suction, and after cutting the upper part of the parison, compressed air was discharged. Was used to perform blow molding.

Screw diameter Temperature Molded product layer ratio Screw A 25 mmφ 210 ° C. 10% Screw B 50 mmφ 210 ° C. 90% Die head {210 ° C.}

Resin Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene was added with a density of 0.87%.
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, ethylene / α-olefin copolymer resin
Screw B: A material obtained by mixing a 1: 1 mixture of an ethylene-propylene block copolymer resin having an MFR of 0.5 and a recycled material of the present molded article with a MFR of 0.5 added with 0% by weight.

Labels used The outer layer surface was subjected to back printing using CPP, and the surface was subjected to aluminum evaporation and further applied with a heat sealant.
High gloss label with%.

Example 4 Using a multilayer blow molding machine having the following three screw extruders, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. The parison was previously inserted into a blow mold having a flat bottle-shaped cavity with a capacity of 800 ml, in which a glossy label was previously inserted into a correct position by an inserter and held by suction, and after cutting the upper part of the parison, compressed air was discharged. Was used to perform blow molding.

Screw diameter Temperature Molded product layer ratio Screw A 25mmφ 210 ° C 10% Screw B 50mmφ 210 ° C 80% Screw C 25mmφ 210 ° C 10% Die head {210 ° C}

Resin used Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene and a density of 0.87
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, ethylene / α-olefin copolymer resin
A polypropylene random copolymer resin having an MFR of 10.0 added with 0% by weight Screw B: A material obtained by mixing an ethylene-propylene block copolymer resin having an MFR of 0.5 and a recycled material of the molded article in a ratio of 1: 1 C: ethylene-propylene block copolymer having an MFR of 0.5

Label used The outer layer surface was subjected to back printing using CPP. Aluminum was deposited and a heat sealant was further applied.
High gloss label with%.

Example 5 Using a multilayer blow molding machine having three screw extruders as described below, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. The parison was previously inserted into a blow mold having a flat bottle-shaped cavity with a capacity of 800 ml, in which a glossy label was previously inserted into a correct position by an inserter and held by suction, and after cutting the upper part of the parison, compressed air was discharged. Was used to perform blow molding.

Screw diameter Temperature Molded product layer ratio Screw A 25mmφ 210 ° C 10% Screw B 50mmφ 200 ° C 80% Screw C 25mmφ 190 ° C 10% Die head {210 ° C}

Resin Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene was added with a density of 0.87%.
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, ethylene / α-olefin copolymer resin
Screw B: A high-density polyethylene resin having an MFR of 0.5, a density of 0.95 and a recycled material of the molded article added with 0% by weight and having a MFR of 10.0:
Screw C: High-density polyethylene resin with MFR of 0.5 and density of 0.95

Labels Used The outer layer surface was backprinted using CPP, and the surface was coated with aluminum and further coated with a heat sealant.
High gloss label with%.

Comparative Example 1 Using a multilayer blow molding machine having the following two screw extruders, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed through a blow head. The parison was previously inserted into a blow mold having a flat bottle-shaped cavity with a capacity of 800 ml, in which a glossy label was previously inserted into a correct position by an inserter and held by suction, and after cutting the upper part of the parison, compressed air was discharged. Was used to perform blow molding.

Screw diameter Temperature Molded product layer ratio Screw A 25 mmφ 210 ° C. 10% Screw B 50 mmφ 210 ° C. 90% Die head {210 ° C.}

Resin Screw A: A polypropylene random copolymer resin containing 1.9% by weight of ethylene was added with a density of 0.87%.
g / cm ³ of a polyethylene resin at 10.0% by weight, and a benzylidene sorbitol compound as a nucleating agent of 1000 wt.
ppm, ethylene / α-olefin copolymer resin
0 wt% added melt flow rate (JIS-K67
58, hereinafter referred to as MFR, unit g / 10 min) is 10.0
Screw copolymer B: ethylene-propylene block copolymer resin with MFR of 0.5

Label to be used A label having a gloss of 11% with a heat sealant applied to the back surface using YUPO for the base material.

Comparative Example 2 Using a multilayer blow molding machine having the following two screw extruders, the following resin was plasticized and extruded by an extruder, and a laminated parison was formed via a blow head. The parison was sandwiched in a blow mold having a cylindrical bottle-shaped cavity with a capacity of 300 ml, and after cutting the upper part of the parison, blow molding was performed using compressed air.

Screw diameter Temperature Molded product layer ratio Screw A 25 mmφ 210 ° C. 10% Screw B 50 mmφ 210 ° C. 90% Die head {210 ° C.}

Resin used Screw A: Polypropylene homopolymer having MFR of 0.5 Screw B: Ethylene-propylene block copolymer resin having MFR of 0.5

Label used: The surface of the back layer printed with CPP on the outer layer surface was subjected to aluminum vapor deposition and further coated with a heat sealant.
High gloss label with%.

The appearance of the molded article in each of the examples was good.

<Physical Properties Table> Outer layer gloss (%) Drop strength Resin part Label part Gloss difference (number of cracks) Example 1 81 105 24 0 Example 2 83 105 22 0 Example 3 82 105 230 0 Example 4 80 105 25 0 Example 5 81 105 24 0 Comparative Example 1 81 11 70 0 Comparative Example 2 62 105 43 7 Note) The glossiness is based on JIS Z8741 60 degree mirror gloss. Drop strength n = 10, each sample 10 times, 1.2m
Drop, 5 ° C.

[0043]

According to the present invention, an in-mold type labeled plastic container having good appearance and surface gloss and good physical properties such as drop impact at low temperature is obtained.

(56) References JP-A-6-320689 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 1/00-1 / 48

Claims (4)

(57) [Claims] 1. A multi-layer plastic container with a label by an in-mold method in which a label and a container are integrated by molding after inserting the label in a mold in advance, using a polypropylene random copolymer resin as an outermost layer, A multi-layer plastic container provided with at least one polyolefin resin layer, wherein the polypropylene random copolymer resin used for the outermost layer contains 0.5 to 2.0% by weight of ethylene and has a density of 0.94 g / 2.0 to 15.0% by weight of polyethylene resin of not more than ³ cm ³ and 500 to
Melt flow rate (JIS-K6758, hereinafter referred to as MFR, unit: g, 3000 ppm, ethylene / α-olefin copolymer resin added at 2.0 to 30.0% by weight)
/ 10 min) is a resin of 40.0 or less, and the label has a glossiness, and a difference in glossiness between the resin surface of the multilayer plastic container and the resin is 30%.
A plastic container with a label characterized by being within. 2. A multi-layer plastic container with a label by an in-mold method in which a label is inserted into a mold in advance, and the label and the container are integrated by molding, wherein a polypropylene random copolymer resin is used for an outermost layer, and A multi-layer plastic container provided with at least one polyolefin resin layer, wherein the polypropylene random copolymer resin used for the outermost layer contains 0.5 to 2.0% by weight of ethylene and has a density of 0.94 g / 2.0 to 15.0% by weight of polyethylene resin of not more than ³ cm ³ and 500 to
MFR of 3000 ppm, propylene / α-olefin copolymer resin added at 2.0 to 30.0% by weight is 4
It is a multilayer plastic container that is a resin of 0.0 or less,
A plastic container with a label, wherein the label has a glossiness, and a difference in glossiness between the resin surface of the multilayer plastic container and the resin surface is within 30%. 3. The multi-layer plastic container according to claim 1, wherein a recycled material comprising the multi-layer plastic container is added to an innermost layer and has at least two layers. container. 4. The multilayer plastic container according to claim 1, wherein a recycled material composed of the multilayer plastic container is added to the second layer from the innermost layer to form at least three layers. Multilayer plastic container with label having.