JPS5910907B2 - Easy-peel packaging material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packaging material coated with plastic such as polyethylene, which allows the lid of a paper cup or the like to be easily peeled off.

Conventionally, as a packaging material imparted with easy peelability, a paper cup or the like coated with a plastic such as polyethylene is sealed with a hot-melt coated lid.

Such conventional hot melt agents use ethylene vinyl acetate copolymer (vinyl acetate content 15 to 40% (W/W)) as a base polymer, and have a melt index in the range of 200 to 400. It is used.

During normal use, hot melt 5 contains tackifiers such as rosin, wax, antioxidants, fillers, etc.
Coat the lid material using a coater. On the other hand, paper cups use paper material coated with polyethylene. Such a paper cup is filled with contents, covered with a lid, and sealed by hot pressing at the edge of the cup. In such a container, when the lid is pulled apart for 10 minutes, the hot melt layer causes cohesive failure and exhibits easy peelability. However, hot-melt agents may undergo deterioration due to oxidation during heating and melting, and since hot-melt agents are highly temperature-dependent, their cohesive strength decreases at high temperatures and the joint strength decreases; In this case, the cohesive force may become excessive and cause interfacial failure. On the other hand, the container is mainly made of paper coated with polyethylene, and considering the adhesive strength between the two and the adhesive strength between the hot melt agent on the lid and the polyethylene coated on the cup, the paper on the cup and the polyethylene coated on the cup are If the adhesive force between the coated polyethylene and the hot melt agent is stronger than the adhesive force between the coated polyethylene and the hot melt agent, peeling will occur between the paper in the cup and the polyethylene coated on it, resulting in so-called paper peeling. happened, 25
In particular, the edge portion of the cup is often curled outward, and in this case, the above-mentioned paper peeling phenomenon is particularly likely to occur.
The present invention aims to improve such drawbacks, and the gist of the present invention is that the above-mentioned lid material is made of polypropylene or ethylene propylene copolymer 30 to 90% of the paper 30.
% (W/W), ethylene-vinyl acetate copolymer containing 1-40% (W/w) vinyl acetate 10-70% (
W/W), rosin-based tackifier 1-25% (W/W)
The object of the present invention is to provide a container with an easily removable lid using a coating coated with a composition consisting of the following.

In addition to rosin, the tackifier in the hot melt agent used for the lid material includes modified rosin, polyterpene resin, modified terpene, aliphatic hydrocarbon, cyclopentadiene resin, aromatic petroleum resin, styrene resin, etc. be done. By extrusion coating the above-mentioned composition onto a paper serving as a lid material, and then thermocompression bonding the lid to a paper cup made of polyethylene coated paper, a container with excellent stability over time and easy peeling without causing peeling of the paper can be created. was gotten.

In the present invention, the composition coated on the lid is ethylene monoacetate vinyl copolymer, polyethylene, ethylene-ethyl acrylate copolymer, etc. blended with polypropylene, which has low heat-fusibility with polyethylene, and a tackifier. Since these are thermally fused to the coated polyethylene of the paper cup, deterioration in strength over time and the natural peeling phenomenon caused by oil adhering during curling of the edge of the cup opening are eliminated. A lid coated with such a composition can be used for plastic cups made of polypropylene, polystyrene, expanded polystyrene, etc. in addition to polyethylene, and therefore can also be used as a packaging material for the plastic itself. Next, an example will be described.

Example lid material: paper (58V/I)/polyethylene (15μ)
/Aluminum (15μ) was extruded and coated with the following composition at about 200°C.

When the thus obtained lid was heat-pressed onto a polyethylene-coated paper cup under various conditions, it showed favorable peelability within the temperature range of 120 to 180°C and thermocompression bonding time of 0.5 to 1.5 seconds. It took 300-400 y/container edge to pull this lid apart in a tensile tester.

Claims (1)

[Claims] 1 Consists of a composite material whose innermost layer is a synthetic resin such as polyethylene, which serves as the receiver body, and a composite material that serves as the lid material,
Polypropylene or ethylene-propylene copolymer 30 to 90% (W/W) is added to the inside of the composite material that becomes the lid material.
), ethylene-vinyl acetate copolymer containing 1-40% (W/W) of vinyl acetate or polyethylene, 10-70% (W/W) of ethylene-ethyl acrylate copolymer
1. An easily removable packaging material characterized by being extrusion coated with a composition containing 1 to 25% (W/W) of a tackifier such as rosin and a tackifier such as rosin.