JPS5820663A - Stretch film for packing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretch film for food packaging.

Conventionally, 11! for tray packaging (pre-pack), etc. ! The stretch film used is generally vinyl chloride resin Nw.
t-based ones are used.

However, most of the uses of this type of film are for food packaging, and there are problems with food hygiene due to chloride and vinyl chloride release, and the generation of chlorine gas when incinerated after disposal. It is undesirable. For this reason, in recent years, in place of the above-mentioned films, stretch films containing 1IllI-free yy regioctic-1,2-borabutadiene or ethylene-vinyl acetate copolymer as the main components have been developed for food hygiene reasons. 1. There are many food hygiene issues, such as no generation of harmful gases during incineration, low water vapor permeability to prevent food loss, and low gas permeability, which is essential for Shufu packaging. Advantages v'FI. Usually, an automatic packaging machine is used to wrap one food in a tray using stretch film. When applying heat**, it is required that the stretch film has a wide temperature range in which it can be touched. This is automatic color *II ripe W! This is because the normal temperature is not necessarily kept constant, and the degree of heat welding of the stretch film changes depending on the pressure based on the weight of the food to be packaged. However, the stretch film mainly composed of the above-mentioned range otakutech-1,2-polybutadiene or ethylene-vinyl acetate copolymer has a set temperature range of 40 to 50 °C. ℃, the temperature change slope that can be touched is extremely narrow, making it extremely unsuitable for automatic packaging machines, and the film parts other than the heat contact area melt and open holes occur. fvn geotactic
At present, stretch films containing 1,2-polybutadiene or ethylene-vinyl acetate copolymers as main components are not widely used.

In addition, Stretch Fill AN's passion! l! In the snow
The reproduction of the phenomenon in which film parts other than the heat-welding W part melt and create holes, and the evaluation of its improvement, are based on the belt heater part t'120 where the film vases in the packaging machine.
~18[Toner set at 1℃ and wrapped in strede]
This is done by leaving the tray stationary for a few seconds on a hot plate and observing the shape of the hole at the bottom of the tray.

As mentioned above, the stretch film containing Vy regioctic-1,2-polyptadiene or ethylene-vinyl acetate copolymer as a main component has the above-mentioned drawbacks in terms of heat resistance. Therefore, in order to improve the heat resistance of these compounds, the present inventor used 1,2-bobutadiene wtllll, and in order to improve the heat resistance, it is necessary to increase the crystallinity. However, Shifujiotactic 1
, 2-Polybutadiene crystallization charcoal [It is virtually impossible to raise it above 40% by weight, and it is simply crystallized l! Although the melting point improves slightly by simply increasing Fv, 1. As the degree of crystallinity increases, the melting point becomes sharper, and there is a limit to how much heat resistance can be improved. In addition, as the crystallized carbon content increases, the numbing point of the film during stretching, which is the most important stretch film, becomes clear, which has a negative impact on the stretch and recovery required for stretch films during automatic packaging. , there is a risk of damaging the appearance of the stretch wrapper.

It has the necessary elasticity for stretch film for automatic packaging.
As a method for evaluating offshore return, a medium-sized 2m long 10awr cut stretch film specimen was placed in a V tube in a normal tensile testing machine, and the test piece was placed offshore at a tensile speed of 500cm and returned automatically. , Hysteria! A method is used in which the lV sloop is recorded on recording paper and judged based on its shape.

The present invention solves the drawbacks such as heat resistance of the Netrette packaging film containing Rangeotactic-1゜2-bobutadiene as a main component, and provides a film suitable for stretch packaging using an automatic packaging machine. For this purpose, a film whose main component is Syndiotactic FTSKU 1.2-polybutadiene resin is stretched and subjected to electron irradiation, and the heat resistance is improved by utilizing the crosslinking reaction that occurs due to the irradiation.

The present invention will be explained in detail below.

First, the crystallization of the present invention ζ2! As yy Geodakdec 1,2-polybutadiene with a weight of 20 to 4°,
For example, among the J8RRB (product name) manufactured by Hikidaiei Gomu (trade name), those falling within the scope of the above claims may be used. This microwave otaku detsuku 1,2-polyptage y
is crystallized! is 20 to 40% by weight, preferably 25 to 35%
Weight - is used, but crystallized charcoal weighs 20°
If it is less than -, the melt viscosity will be so low that it will be impossible to melt extrude it with a square die or cheek error die, which is not preferable. Further, if the degree of crystallinity is 40% by weight or more, the melting point becomes sharp as the degree of crystallinity increases, and there is no effect of improving heat resistance, which is not preferable.

In order to prevent water droplets from adhering to the 1,2-polypdadiene resin and clouding the film, and at the same time to provide sufficient deviceability as a stretch film, νy diotac is added by 1 to 2.5 weight. Examples of antifogging agents that are preferred include sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acids, acid esters, etrecyol, propylene glycol, and the like. To add an antifogging agent, in addition to adding antifogging agent v4i8 to syndiotactic-1,2-polybutadieno resin, prepare the antifogging agent [mixed master patch t'6] in advance and mix it in the required amount. Good too.

Next, the method for manufacturing stretch film using the above materials will be explained in detail.
．． 2-Popta e-engineering@resin is the same as polyolefin resin, it is yyfla V1! In law,! The film can be formed by a die method, etc., but in order to complete the present invention, it is not necessary to use any of the methods.
Although it may be used, the inflation method is preferable because it can be stretched in the two-wheel direction 1llIIF.I/1 In the present invention, lindiotactic-1,2-botubutadiene [stretch] containing the antifogging agent detailed above is used. I! under a constant discharge amount when forming a film of about 10 to 50 tones, preferably 14 to 20 tones required for a film. Membrane direction C vertical direction)
15 to 5 times preferable (or 2 to &5 times, and 15 to 5 times the die diameter), preferably 2 to 3.
5 times simultaneous biaxial stretching process Y, or biaxial stretching process at the same time as film formation, but it is also possible to perform biaxial stretching in film Vll process with a stretching ratio below a predetermined value. If the stretching is less than 15 times in both the direction and the grain direction, not only will the film carbonization as a stretch film not be maintained, but the film will have insufficient rigidity. mosquito,
This is not preferred because stretching becomes extremely difficult.

Next, explaining the electron beam irradiation in the present invention, the electron beam can be a linear filament type, for example, Electro Curtain (product name) manufactured by HG Technologies. If a linear filament type electron beam source is equipped with a filament whose length corresponds to the width of the irradiated film, etc., electrons will be generated from the filament. Therefore, the electron beam extraction efficiency is good without increasing the acceleration voltage Y, and relatively low energy electrons of 11 V can be generated.

There is a roughly proportional relationship between the energy of the electron beam and the degree of penetration of the electron beam into a substance, and the thickness of the stretch film used in the present invention is 10 to 50 degrees, preferably 14 to 20 degrees, as described above. The energy of the electron beam required to penetrate these films is 100 to 200 KeV.
is sufficient. Energy above 200 to 07 is unnecessary, and below 100 KeV, the electron beam extraction efficiency is poor and it is difficult to maintain a stable irradiation dose.

Next, the required electron beam irradiation dose in the present invention is 0.5
-5 Mrad, preferably 1-5 Mrad.

Syngeo Tough Deck-1 with electron 11JI shooting under the above conditions
, 2-polybutadiene as a main component, and the stretched film undergoes a crosslinking reaction, and as a result, its heat resistance is improved to the point where it does not melt even at 200°C. It should be noted that an irradiation dose of 0.5 Mracl or less is not preferable because the effect of improving heat resistance is not noticeable, and an irradiation dose of 5 Mracl or more is not preferable.
Although a crosslinking reaction occurs, not only does it not improve heat resistance much, but it also causes a decomposition reaction (which is undesirable because it occurs simultaneously).

A film containing butadiene as a main component, which was created for use in microwave ovens, was continuously passed under the electron generation window of an electron beam source.
After being cross-linked or rolled up as a one-strength film, r:WM
Child 11! Furthermore, in this case, it is preferable to use a self-electronic type as an electron beam generator because continuous operation is possible.

Microwave Otaku Chiwakoo manufactured as above 1.
The 4-stretch film, which is mainly composed of 2-polybutadiene 7V, has good heat resistance, and its elasticity is very similar to that of a stretch film whose main component is polyvinyl chloride. Better than film,
It was easy to heat and snow.

Example Syndiotactic-1,2-polybutadiene (Japan @
Manufactured by Igomu, product name, J8RHs 850° crystal ratio change 29 weight -, melt flow index, 3iP710
0.411 parts of sorbitan fatty acid ester C Hanatama Soap Manufactured Span $5) and 100 parts by weight of sorbitan fatty acid ester (Kao Soap Flljl)
I Atmos 300) tst volume part! Using warmed resin i,
Leaf-Kinilar die [With the prepared IYFRASYOY machine, the thickness after rolling is 3 times the film direction (C vertical direction) and 3 times perpendicular to the film forming direction (in the grain direction).
Let me be your voice! It was filmed. This film is so good
It is folded into two pieces at the upper nip a-rule of the gy equipment, and then heated to an accelerating voltage of 150 KV using a linear filament type electron*ia irradiation equipment attached to a part of the in-place WV equipment.
, ii. After passing under the electron beam generation window under the condition of the earing amount t5 Mrad to cause a crosslinking reaction, both *W power and L are turned off.

A stretch film was obtained. “Using the obtained stretch film, place seven cucumbers on a tray made of foamed sterol (Nice BO% x 200%) and put it on an automatic stretch packaging machine (B-chi 6090 model manufactured by Omori Machinery Co., Ltd.)
Automatic packaging was carried out at The stretch film in the final step was melted at a temperature of 150 to 160° C., and good placement was obtained without any problems such as opening. Furthermore, the elasticity and elasticity of the obtained stretch film were similar to those of a stretch film mainly made of polyvinyl chloride, and the appearance of the finished Thulette film was very good.

39C

Claims (1)

[Claims] (1) The main component is a pyresectic-1,2-polybutadiene resin with a crystallinity of 20 to 40% by weight, and is rolled by 15 to 5 times in the direction of film formation and 15 to 5 times in the direction perpendicular to the direction of film formation. A stretch film for packaging, which is formed so as to have a thickness of 10+a to 50+, and is crosslinked by electron beam irradiation at an acceleration voltage of 100 to 200 KV and an irradiation dose of 0.5 to 5 Mrad. The stretch film for packaging according to claim 11!1, characterized in that 0.1 to 4.5 parts by weight of an antifogging agent is added to 100 parts by weight of the resin.