JP2672992B2 - Shrink film for half wrap - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a shrink wrapping film in which bottles, cans and the like are placed on a cardboard tray for integrated wrapping.

[Prior Art] A conventional sleeve package shown in FIG. 3 is generally used as an integrated package using a shrink film.

[Problems to be Solved by the Invention] The conventional integrated packaging using the shrink film also covers the lower surface of the corrugated cardboard tray which does not require coating of the film, so that the film price increases accordingly. It was

[Means for Solving the Problems] The present invention provides a shrink film suitable for a so-called half wrap in which only a side portion of a cardboard tray on which a bottle and a can are placed is covered with a shrink film.

 This will be specifically described below.

The shrink film for half-wrap of the present invention has a melt index (hereinafter referred to as MI) of 0.1 to 10 g / 10 minutes and a density of 0.9.
Ethylene vinyl acetate copolymer with 50g / cm ³ or less and vinyl acetate or ethyl acrylate content of 3 to 20wt% (hereinafter EV
A) or ethylene ethyl acrylate copolymer (hereinafter referred to as EEA), or density 0.935 g / cm ³ or less, MI 4
~ 10g / 10min low density polyethylene (hereinafter referred to as LDPE)
Layer (A layer) and MI 0.1-3.9g / 10min, density 0.950g
It is composed of a layer (layer B) made of LDPE of not more than / cm ³ and has a longitudinal shrinkage of 65% or more (shrinkage is measured in glycerin at 120 ° C.) and a transverse shrinkage of −10. It has a characteristic of ~ 10%.

Further, as described in the second aspect, the thickness composition ratio of the A layer and the B layer is preferably in the range of 1: 1 to 5.

Hereinafter, description will be given based on the drawing (FIG. 2) showing a package using the shrink film for half wrap (FIG. 1) of the present invention. A strip of hot melt adhesive 4 is applied to both sides in the longitudinal direction of the corrugated cardboard tray 2 on which the can 3 is placed.
Shrink film 1 for half wrap with layers inside
The leading edge of the film (hereinafter referred to as a film) is pressed against the hot-melt adhesive applied to one side surface and the trailing edge is pressed against the hot-melt adhesive applied to the other side surface for pressure-bonding to perform integrated packaging. Therefore, in this integrated package, the film 1 is fixed in the longitudinal direction with a hot melt adhesive to cover the can 3, and is heated to shrink the film 1. At this time, the ends of the semi-molten film 1 in contact with both sides of the corrugated board tray 2 in the lateral direction are pressed by a roll or the like to be pressed against the side surface of the corrugated board tray 2.

The film of the present invention has properties in the above range, but has a vinyl acetate or ethyl acrylate content of 3 wt.
If it is less than 20% by weight, the adhesion between the corrugated paper tray and the film becomes poor, and if it exceeds 20% by weight, blocking occurs and the productivity of the film becomes poor. MI of EVA or EEA is 0.1-10g / 1
When it is out of the range of 0 minutes, the film processability is poor, and when the density exceeds 0.950 g / cm ³ , the low temperature shrinkability is poor.
When the MI of LDPE of layer A is less than 4 g / 10 minutes, the adhesiveness to the corrugated paper tray becomes poor, and when it exceeds 10 g / 10 minutes, the productivity becomes poor. Further, when the density of the LDPE exceeds 0.935 g / cm ³ , the adhesiveness to the corrugated paper tray becomes poor. MI of LDPE of layer B
If it is less than 0.1 g / 10 minutes, the molding force will be poor, and if it exceeds 3.9 g / 10 minutes, the binding force will be reduced. When the density exceeds 0.950 g / cm ³ , low temperature shrinkability and transparency deteriorate. On the other hand, if the vertical and horizontal shrinkage ratios of the film are out of the above ranges, the finish will be poor. In particular, when the shrinkage ratio in the lateral direction exceeds 10%, the shrinkage in the lateral direction becomes large, and the film comes off from the side surface of the corrugated board tray, resulting in poor sealing performance. In the thickness composition ratio of A layer and B layer, A
When the layer is thinner than the above range, the adhesive strength is low, and when the layer is thick, the cost is high and the cohesive strength is low.

By performing corona discharge treatment on the layer A of the film of the present invention, the adhesiveness between the film and the cardboard tray can be further improved.

[Effect of the invention] Since the film of the present invention has the above-mentioned characteristics, the film is well adhered to the side of the corrugated cardboard tray which is not coated with the hot-melt adhesive when integrated and packaged. It is possible to prevent such intrusion, and it is possible to obtain a product having a strong binding force and a good appearance.

[Examples] Examples and comparative examples are shown below.

Examples 1 to 3, Comparative Example 1

[Brief description of the drawings]

FIG. 1 is a sectional view of a shrink film for a half wrap according to the present invention, and FIG. 2 is a perspective view showing an integrated package using the film. FIG. 3 is a perspective view showing a conventional sleeve package. 1 ... Shrink film for half wrap 2 ... Corrugated cardboard tray 3 ... Can 4 ... Hot melt adhesive

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // B29K 23:00 105: 02 B29L 9:00

Claims (2)

(57) [Claims] 1. Melt index 0.1 to 10 g / 10 minutes, density
0.950 g / cm ³ or less, vinyl acetate or ethyl acrylate content of 3-20 wt% of ethylene vinyl acetate copolymer or ethylene-ethyl acrylate copolymer, or a melt index 4~10g / 10 min, density 0.935 g / cm Layer consisting of low density polyethylene of ³ or less (A layer) and melt index 0.1
It is composed of a layer (layer B) made of low density polyethylene having a density of up to 3.9 g / 10 min and a density of 0.950 g / cm ³ or less, and has a longitudinal shrinkage of 65.
% Shrink film with a transverse shrinkage of -10 to 10%. 2. The shrink wrap film for a half lap according to claim 1, wherein the thickness composition ratio of the A layer and the B layer is 1: 1 to 5.