JPS60118729A - Stretch film - Google Patents

Abstract

PURPOSE:To obtain a stretch film of vinyl chloride resin having improved printability on the surface of the film, obtained by blending polyvinyl chloride resin with specific amounts of specified stabilizer and anti-fogging agent, providing the blend with specific elongation characteristics. CONSTITUTION:(A) 100pts.wt. polyvinyl chloride resin is blended with (B) 15- 60pts.wt. plasticizer (e.g., adipic acid ester of higher alcohol, etc.) to give a stretch film, which is blended with (C) Ca-Zn liquid stabilizer and (D) 2-3pts.wt. total amounts of D1 and D2 of anti-fogging agent consisting of D1: polyoxyethylene alkyl ether having 4-20mol of ethylene oxide addition and 12-20C alkyl group and D2: sorbitan fatty acid ester comprising a fatty acid containing 9- 17C alkyl group in a ratio of D1:D2 of (1:1)-(1:1.5). The composition is melted under heating, and molded to give a film having 120-300g/cm longitudinal tensile load and 30-60g/cm lateral tensile load at 25% elongation measured at 200mm./ min stress rate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretch film, and particularly to a stretch film made of vinyl chloride resin that has excellent printability on the film surface.

So-called stretch packaging is used as a means of packaging foods, etc., in which the product is wrapped while being stretched, and the ends of the film are made to stick (self-adhesive) together by simply pressing the folded ends of the film lightly with fingers or the like. This is commonly done in supermarkets, etc.

For the above-mentioned trench packaging, a vinyl chloride resin trench film, which is made by adding a plasticizer to polyvinyl chloride resin, is most commonly used because it has excellent transparency and self-adhesiveness.

On the other hand, for packaging materials, it is desired to print information such as the contents of the package on the surface as a quality display and advertising function. However, when printing on the above-mentioned PVC resin stretch film, misalignment of the printed pattern is likely to occur due to the ease of stretching of the film due to the characteristics of the film itself, and after printing, the added plasticizer etc. Since the printing ink is blown out onto the film surface (bleed), troubles such as the printing ink peeling off from the surface and being transferred to other films (bleeding) are likely to occur.

In order to solve the above-mentioned problems, the present invention uses a specific composition and has discovered a stretch film having specific tensile elongation characteristics. 73% plasticizer
-~ In the trench film formed by mixing 0 parts by weight of C, as a stabilizer! It is made by adding (A) polyoxyethylene alkyl ether and (B) sorbitan fatty acid ester as an a-Zn-based liquid stabilizer and an antifogging agent, and the weight ratio of the above (N and (Bl) is /:/ ~
/: /, within the range of 3, and (the total amount of Al and CB+ is within the range of 2.0 to 3.0 parts by weight, and the tensile speed of the film is 2t% elongation measured at xoown 1 minute) The stretch film is characterized by having a tensile load of 20 to 60 cm in the longitudinal direction and 30 to 60 cm in the transverse direction.

Polyvinyl chloride resin (
Hereinafter referred to as rPVOJ. ) and plasticizers may be those commonly used, and the PVC used may be a homopolymer or a copolymer containing small amounts of other components. Further, examples of the plasticizer include adipic acid ester epoxylated vegetable oil, which is a higher alcohol, and the amount thereof is in the range of 75 to 60 parts by weight per 100 parts by weight of PVO.

As the stabilizer for the film of the present invention, a CaZn-based liquid stabilizer is used. The stabilizer must be liquid at room temperature, and the use of powdered metal soaps such as stearic acid Oa
This is disadvantageous because it promotes blowing of the additive onto the film surface.

As the antifogging agent for imparting antifogging properties and appropriate slipperiness to the film of the present invention, it is necessary to use a combination of the above-mentioned (A) polyoxyethylene alkyl ether and (B) sorbitan fatty acid ester. (AJ polyoxyethylene alkyl ether 75=<z~.?0 and consists of an alkyl group with carbon number/2~.20, specifically, polyoxyethylene lauryl ether and polyoxyethylene stearyl (The sorbitan fatty acid ester of Bl is composed of a fatty acid having an alkyl group having 7 to 7 carbon atoms, and specific examples thereof include sorbitan laurate and sorbitan myristate. .

Regarding the addition ratio, the weight ratio of (A) and (131 is /:
／〜／：／． ! ; and the amount of joining of (A) and (B) is in the range of 2.0 to 3.0 folds. At the above ratio (
Those with Bl less than 7 have poor antifogging properties, and /. If the value exceeds j, transfer of printing ink is likely to occur with many blowouts on the film surface.

In addition to the above-mentioned additives, a coloring agent or the like may be added as necessary.

First, a film is formed by heating and melting the composition having the above contents and then extruding it from an extruder.

The film after film formation must have a specific tensile elongation property, which is 2t measured at a tensile rate of 20θ/min.
% elongation tensile load in longitudinal direction 7, 20 to 3 oof/er
r. , in the range of 30 to 30 f/cm in the lateral direction.

The reason for giving this property is that when printing on the film surface using a method such as gravure printing, tension between the rolls of the printing machine is applied in the longitudinal direction of the film, stretching the film and causing pattern misalignment. It is better to have the elongation as small as possible, and at the above tensile load /2θ! /lyn or higher is required. However, if it exceeds 3009/lyn, uneven wrinkles are likely to occur during the printing process, which is disadvantageous. In addition, when final packaging is performed,
Since the film is usually stretched in the transverse direction for packaging, a film that has moderate stretchability in the transverse direction has good workability during packaging, and the above tensile load must be 6097 cm or less.

However, if it is less than 3t)97cm, it will affect the fillem elongation in the longitudinal direction and increase the longitudinal elongation, which is disadvantageous.

The film manufacturing conditions for imparting the above tensile elongation properties vary depending on the molding machine used, but when using the T-die method, the ratio of the cooling roll speed immediately after the extruder mouth to the final take-up roll speed is set to / It can be obtained by setting it to about S~/,j.

Next, the present invention will be explained in detail using examples.

Example / PVO/θθ weight parts, plasticizer 4I-5 weight parts (diisononyl adipate 30 weight parts, epoxidized soybean oil/J
'fi Okabe) C! A composition consisting of 7 parts by weight of a-Zn liquid stabilizer and the contents listed in Table 1 as an antifogging agent was heated and mixed, and the mixture was melt-extruded in an extrusion mode to obtain a thickness/gμ.
A trench film was obtained. As for the comparative product, 0.7 parts by weight of each of powdered stearic acid Oa and stearic acid Zn were added instead of the Oa-Zn liquid stabilizer. The evaluation results of the antifogging properties, ink printability, and ink transferability of each film obtained are shown in Table 1.

The evaluation method for each performance is as follows.

/) Anti-fogging property 7: Place the freshly cut pieces at -20°C into a tray, cover the openings with each film, and place in a refrigerated case at about S°C. 1
After 0 minutes, remove the film and check the degree of cloudiness. There is no clouding at all (◎), there are large water droplets on the inside of the film but the contents are clearly visible (○), and the contents are not clearly visible (○). x).

Ink printing properties Commercially available cellophane tape was attached to the printed surface of each film that was gravure printed using Toyo Ink Manufacturing ■ ink, XGO, :ZVC, and the degree of ink peeling when the tape was peeled off. I saw it. Ink that does not peel off at all (◎)
, those with slight peeling (○), and those with about half of the ink peeled off from the printed surface from which the tape was removed (x).

3] Ink transferability A roll of gravure-printed film using Toyo Ink Manufacture's ink, XRO, and ZVA is placed in an atmosphere at JJ℃! After leaving it for a day, the presence or absence of ink transfer was checked. There is no transfer of ink to the film that comes into contact with the printing surface (
◎), a slight ink transfer was observed but there was no practical problem (○), and approximately half of the printed surface was transferred (△).

Table - / POELE; Polyogine ethylene lauryl ether SML; Sorbitan monolaurate PGMO; Polyglycerin monoole 1 GMO; Glycerin monoole 1 As is clear from Table - /, the products of the present invention are:
It can be seen that all three performances are excellent.

On the other hand, the comparative products using the antifogging agent of the present invention but with a small number of additives/and the comparative products using powdered stabilizers were inferior in antifogging properties; It can be seen that Comparative Products 3 to 3, which have different anti-fouling agents from those of the invention, are also inferior in one of the three performances.

Example! The composition was the same as that of the product in Example/, and after heating and mixing with a high speed mixer, extrusion molding was performed using a T-die method at an extrusion temperature of 200°C.

In this case, the ratio between the cooling roll speed immediately after the T-die die and the final take-up roll speed is shown in the table below. By using the ratios shown in , and changing the mouth gear, temperature conditions, etc. as appropriate, films having a thickness of /gμ were obtained. For each film, the tensile speed,
A tensile test was conducted at 200 ran/min, and the tensile load at 2j% elongation was measured in the longitudinal and transverse directions of the film. In addition, for each film, manufactured by Toyo Ink Manufacturing ■, Xg02V
Printed using a gravure multicolor printing machine using C3 colors,
The pattern misalignment in printing was measured.

The measurement results are shown in Table 1. Excellent ones with pattern deviation of 0.7 m or less (◎), good ones with 09.!~0.11 am (○), unsightly ones with O,S~0.ly m++1 (△), θ, 6 Something that crosses the threshold and is extremely unsightly (
×) Toshida.

Table 2 From Table 2, it can be seen that samples 3 to j, which are within the scope of the present invention, are good with little pattern deviation. It can be seen that the handle misalignment is large for the sample N116, which has a small tensile load in the longitudinal direction, and the sample N116, which has a small tensile load in the horizontal direction. For sample M7, in which the tensile load in the longitudinal direction was too thick, uneven wrinkles occurred in the film during printing.
Good printing was not possible.

Claims (1)

[Claims] 700 parts by weight of polyvinyl chloride resin and 7j of plasticizer.
In the stretch film formed by mixing ~60 parts by weight, a Ca-Zn liquid stabilizer is added as a stabilizer, and +Al polyquine ethylene alkyl ether and (BJ Nrubitan fatty acid ester) are added as an antifogging agent. The weight ratio of (A) and (BJ is /2/
~/: within the range of t, S, and the total amount of [A) and tB) is within the range of 2.0 to 3.0 parts by weight, and the tensile speed of the film is measured at xovtan/min. x, r
% tensile load at elongation in longitudinal direction /, 2θ ~ 300117c
A stretch film characterized by having a width of 30 to 7 cm in the horizontal direction.