JPS5844465B2 - Nenchiyakuhousouyoufilm Oyobi Sonoseizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is in the field of stretch packaging, which uses the elasticity and self-adhesive properties of a film to wrap items, and is particularly applicable to stretch packaging using a hunt wrapper (manual packaging machine). The present invention relates to an ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA) film suitable as a stretch packaging film for manual packaging, and a method for producing the same.

Stretch packaging methods utilize the flexibility, elasticity, self-adhesiveness, heat sealability, transparency, etc. of stretch packaging films.

Then, by stretching and wrapping the film,
The packaging is tightly packed according to the shape of the packaged items, and the packaging condition is fixed by light pressure bonding or heat sealing, which prevents loss of freshness and loss of weight of the packaged items such as Food R-1, and is hygienic. The quality of the packaged items can be confirmed visually and tactilely, the appearance of the packaged items is beautiful and the commercial value of the packaged items can be significantly increased. There is a need for a film that has excellent features such as being able to be used in both manual packaging machines and high-efficiency automatic packaging machines.

Conventionally, the films used for stretch packaging are made of soft vinyl chloride resin (hereinafter referred to as PV) containing a large amount of plasticizer.
PVC film is mainly used as a material, but because it contains a large amount of plasticizer, it has high water vapor permeability and the packaged items are easily damaged, and the plasticizer transfers to the packaged items. It has disadvantages such as being easy to use, and generating harmful corrosive chlorine gas when the film is cut during packaging or when disposed of by incineration.

Recently, various attempts have been made to develop stretch packaging films that do not have the above-mentioned drawbacks, and in particular, films based on EVA have begun to be developed.

For example, JP-A-49-60352, JP-A-50-3
There is an EVA film disclosed in Japanese Patent No. 4048.

JP-A-49-60352 discloses a stretch packaging film in which 5 to 30 parts by weight of a tackifier such as an aliphatic hydrocarbon resin, rosin, or polyterpene resin is added to EVA.

However, the film made of this composition was
N [120 ~ No. 22] As shown in 22, the coefficient of dynamic friction was extremely large and could not be measured, and there was a phenomenon of blocking of the rolled film, and the entire surface of the film was whitish and could be rubbed with fingers. This has problems such as areas becoming whitish.

Furthermore, JP-A-50-34048 discloses that 1 to 20 parts of a tackifying resin such as a polyterpene resin or hydrogenated petroleum resin and 0.01 to 0.01 parts of a nonionic surfactant such as glycerin fatty acid ester are added to EVA. A composition for stretch packaging) and ilm containing 5 parts is disclosed.

However, the film made of this composition was
As shown in Oni 27 and Oni 28, the above-mentioned Japanese Patent Application Laid-Open No. 49-6035
Although the problems of the film comprising Composition 1 disclosed in Publication No. 2 have been somewhat improved, the film is still insufficient as a stretch packaging film for manual packaging, which is the main purpose of this invention. .

In other words, the roll peeler of the rolled film is large and the film cannot be pulled out smoothly.
It is also a film with a high coefficient of dynamic friction and poor self-adhesion.

Furthermore, contamination in the form of white spots occurs on the surface of the film, and this tendency tends to occur particularly when the amount of the tackifier resin added increases, for example, when it is 3% by weight or more.

As mentioned above, conventionally known EVA-based films are not suitable as stretch wrapping films for manual wrapping, which is the main purpose of the present invention, and suffer from blocking phenomena and high coefficients of dynamic friction. Due to insufficient adhesiveness or self-adhesiveness, packaging workability is extremely poor, it is difficult to obtain packages in good packaging condition, and white spots on the surface of the film may occur. This has disadvantages, such as significantly lowering the commercial value of the packaged product due to contamination.

The inventors (1) took into account the drawbacks of these conventional EVA-based films, and as a result of intensive research to obtain a film suitable for use as a stretch wrapping film for manual wrapping, which is the main purpose of the present invention, This is what led to this invention.

Furthermore, the film of the present invention, which has been appropriately stretched and oriented, exhibits high strength and moderate elongation, and also exhibits necking phenomenon, that is, when the film is stretched, only a portion of the film is greatly stretched. They discovered that the phenomenon of thinning of the material and uneven thickness is eliminated, and when the object is wrapped in a film in stretch packaging, the film does not break at the protrusions of the object, the edges of the tray, etc. In contrast to conventional EVA, it is possible to obtain a good packaging condition with no wrinkles and increase the commercial value of the packaged items.
The adhesive packaging film of the present invention, especially the stretch packaging film for manual wrapping, has been completed by showing that it has properties that cannot be obtained with other type of films.

In other words, one invention has a melt index of 0.
．． 5-20. A vinyl acetate group content of 5 to 40 is selected from a molecular weight polymer-vinyl acetate copolymer, a ring group saturated hydrocarbon resin, an aliphatic hydrocarbon resin, a petroleum resin, an acidic polypropylene resin, and a rosin polyterpene. 0.5 to 5 parts by weight of tackifying resin and 1 to 1 part of mineral oil
0% by weight and 0.1 to 5 parts by weight of a nonionic surfactant, with a coefficient of dynamic friction of 0.5 or less and a degree of haze of 5% or less,
This patented adhesive packaging film is characterized by having a heat shrinkage rate of at least 30%, an elastic recovery rate of 60% or more, and antifogging properties.

Another invention is to melt and extrude the above resin composition through a die having an annular slit, and then reheat the raw fabric that has been quenched and solidified with a liquid once at a temperature of 70 to 140°C to obtain an area stretching ratio of 50 by an inflation method. This is a method for producing a stretched adhesive packaging film, which is characterized by stretching the film at a stretching ratio of 3 to 9 times in the transverse direction.

In this invention, a weight VA having a melt index of 0.5 to 20 and a vinyl acetate group content of 5 to 40 is used.

The melt index is a value measured in accordance with JIS K6760, and an EVA of less than 0.5 will cause the film surface to become rough due to the addition of f-f, resulting in poor transparency and gloss, while an EVA of more than 20 will result in poor film processing. The so-called drawdown phenomenon, in which the film sometimes flows and becomes difficult to mold, is large, making it difficult to process the film, and even if it can be made into a film, the strength is low and there is a strong tendency for film surfaces to block together.

In addition, the vinyl acetate group content is a value determined by elemental analysis, and EVA with less than 5% by weight has a high crystallization rate and poor flexibility, and the resulting film has self-adhesiveness, elastic recovery, and transparency. This results in poor properties such as hardness and gloss, and furthermore, poor stretching orientation stability during processing.

On the other hand, E V A'-, which has a weight of 40% by weight, tends to draw down during film processing and is unstable, and the obtained film has low strength, and the film surfaces cause significant blocking and cannot be peeled off. Become.

In the EVA used in this invention, the melt index is preferably 0.5 to 15, more preferably 0.5 to 10, and the vinyl acetate group content is 5 to 30 weight φ.
, more preferably 5 to 20 weight φ.

The tackifying resin used in this invention includes an alicyclic saturated hydrocarbon resin, an aliphatic hydrocarbon resin such as an olefin or diolefin polymer, an aromatic petroleum resin, and an amorphous resin with a molecular weight of 10,000 to 10,000.0. A type selected from the following: acidic polypropylene, gum rosin, wood rosin, hydrogenated rosin, rosins such as rosin obtained by esterifying these with polyhydric alcohols, and Botterupenes, which are polymers such as α-pinene and β-pinene. or a mixture of two or more, preferably 0.5 to 5% by weight, preferably 1 to 5% by weight
3 Added by weight.

These tackifier resins must be able to impart tackiness with a small amount of addition, have excellent compatibility with EVA and other additives, and not inhibit the properties of the resulting film such as transparency and gloss. The tackifying resins are selected based on their excellent heat resistance and stability, and preferred tackifying resins include ring group saturated hydrocarbon resins and aliphatic saturated hydrocarbon resins having a softening point of 100° C. or higher.

Addition: If it is less than 0.5% by weight, almost self-adhesive property will be added.
If the amount exceeds 5% by weight, the obtained film may be easily blocked when stored in a roll, its strength may be reduced, and the transparency and gloss of the film may be impaired. The film is difficult to be put to practical use as an adhesive packaging film due to the fact that contamination in the form of white flag spots is likely to occur on the film surface.

The mineral oil referred to in 1B in this invention is a liquid hydrocarbon consisting of one or a mixture of two or more selected from paraffinic, isoparaffinic, and naphthenic, and has a boiling point of at least 200°C or higher under atmospheric pressure. It should be added 1 to 10 times, preferably 2 to 8 times.

Especially the FDA (Food and Drug Admin)
ist-ration) Subpart F 121.
, white mineral oil as described in FDA Subpart D121.1146, FD
The odorless light hydrocarbons described in A Zabpar 1-D121.1182 are preferred.

These mineral oils plasticize the tackifier resin, plasticize and soften EVA, and significantly increase the self-adhesiveness of the film.Furthermore, unlike tackifier resins such as polybutene, they do not excessively bleed onto the film surface. The surface of the film is sticky and no phenomenon occurs, and by combining the tackifier resin and the mineral oil, it exhibits a unique effect of having high self-adhesiveness and a low coefficient of dynamic friction. .

In addition, the mineral oil contained inside the film prevents light scattering in the dispersion interface layer between EVA and the tackifier resin, and also eliminates unevenness on the film surface and creates a smooth surface. This seems to be because the flat surface reduces light scattering on the film surface, but it further improves the transparency and gloss of the film.

Mineral oil Kunaj, [Shallow L(.

1, 1 size - character φ - not; Akanete t,, t l - The action and effect of the mineral oil described above is not sufficient, and if the weight exceeds 10 weight φ, the resulting film will be plasticized and softened more than necessary, and its strength will be reduced. Not only does this decrease, but the film surface becomes sticky due to the mineral oil that has excessively bled onto the film surface.
However, packaging work efficiency is significantly reduced.

The nonionic surfactant used in this invention is 1'fI of esters of alcohols and fatty acids and derivatives thereof, or a mixture of two or more thereof, and is 0.1 to 5% by weight, preferably 0. .5 to 3 times a day.

In this invention, glycerin, polyglycerin, sorbitan, sorbitol 1 hale, penqueli li 1 hale,
Alcohols such as polyethylene glycol and polypropylene glycol 8, and alkyl group 0) Straight chain saturated fatty acids with 5 to 13 carbon atoms or alkyl groups with 17 to 21 carbon atoms
fatty acid esters consisting of linear unsaturated fatty acids; or ethylene oxide adducts of the above fatty acid esters (
n-5 to 20) Polyoxyethylene alkylphenol ethers are preferred, and those that are liquid under normal conditions are particularly preferred.

In particular, monoesters and polyesters of glycerin, polyglycerin, sorbitan, polyethylene glycol and oleic acid, lauric acid, and erucic acid, and ethylene oxide adducts of these fatty acid esters (n = 20)
, for example, glycerin monooleate, diglycerin monooleate 1, diglycerin dioleate, diglycerin monolaurate, sorbitan monooleate, sorbitan sesquioleate 1, erucic acid monoglyceride,
Polyethylene glycol monolaurate, polyethylene gelicol monooleate-1, polyoxyethylene glyceryl monooleate-1, polyoxyethylene sorbitan monooleate, etc. have antifogging properties and compatibility with EVA and other additives. This is preferable because it does not impair the transparency and gloss of the resulting film.

If the amount of such nonionic surfactant added is less than 0.1 weight φ, it is difficult to provide the necessary antifogging properties, and if the amount is less than 5 weight φ
If the amount exceeds 100%, the added nonionic surfactant will excessively bleed onto the film surface, and as a result, the film surface will be more likely to become contaminated or have a sticky white appearance.

Furthermore, the film of the present invention can be used with the various additives mentioned above.
F:,1,)-r j-;;r)p,,1.9. ((
,,;jl,,1jL21. ii, May B(-'i-
! -1f''lt (□v) A mixture of three types of nonionic surfactants is used, and the amount is added in an amount of 2 to 15% by weight, more preferably 3.5 to 11% by weight based on EvA. It is.

If the additive amount is less than 2% by weight, the adhesive packaging film, which is the object of this invention, will have the necessary properties such as lubricity, self-adhesiveness, transparency, gloss, and antifogging properties. If the added amount exceeds 15% by weight,
Excessive bleeding of additives on the film surface causes the film surface to become sticky, the coefficient of dynamic friction increases and lubricity decreases, EVA is excessively plasticized and softened, etc.) There are disadvantages such as a decrease in the strength of the film, a tendency to cause de-winding phenomenon during film processing, and a decrease in pressure stability.

In addition, in the mixture of these three types of additives, the amount of mineral oil added is \1"'1 amount of adhesive resin (
It is desirable to add at least twice (by weight), preferably at least twice (by weight).

This is because if the amount of mineral oil added is less than the amount of tackifier resin added, the resulting film will be sticky and will suffer from the drawbacks of the resin, such as blocking phenomenon, an increase in the coefficient of dynamic friction, and a decrease in transparency and gloss. This is because it becomes easier to appear.

In order to obtain a film having the above-mentioned various properties necessary for the adhesive packaging film of the present invention, the above-mentioned three types of additives include acids of 1 to 3% by weight of tackifier and 2 to 6% by weight of mineral oil. %, nonionic surfactant 0.5-2
Weight%.

As mentioned above, the film of the present invention has specific E,
By adding specific amounts of a specific tackifier, specific mineral oil, and nonionic surfactant to VA, a synergistic effect of these three types of JEL agents; from this, a new film for adhesive packaging can be obtained. However, especially as a stretch packaging film, it is important that the film has enough strength to not break when stretched during packaging, and that the film can be stretched uniformly without causing the aforementioned necking phenomenon. In order to provide wrinkle-free and tight packaging, the film of the present invention is one in which MU is stretch-oriented.

However, as mentioned above, the film of the present invention is obtained by appropriately rolling a specific EVA composition with 1[P orientation, and has a dynamic friction coefficient of 05 or less, a haze of 5% or less, and a cloudiness of at least 30%. The heating shrinkage rate of 60゜゛Ltθ)I
j single ↑ cow [: ii + l '7ζ bowl -・o, -1 mibi: bodum [I'm going to have a cow.

Here, the dynamic friction coefficient is based on ASTM D-18946
This is a value measured in accordance with 3T, and if the coefficient of dynamic friction is 0.5 or more, the frictional resistance will increase at parts such as the packaged object, the toilet, or the roll part of the packaging machine during packaging, which will not only impede packaging performance. If the film gets caught on the edge of the tray and breaks, or if the wrinkles in the film are not smoothed out enough and the packaging becomes unsightly, the film will be difficult to put into practical use.

Preferably it is 0.4 or less.

Haze is a value measured according to ASTM D-1003-61. If the haze exceeds 5%, the transparency of the film is poor, making it difficult to see through and confirm the packaged item when the product is packaged. This is undesirable in terms of improving the commercial value of the product.

Preferably it is 3% or less.

The heat shrinkage rate is a value measured according to ASTM D-1204-54, and at least 30% means a value of 30% or more even in the direction of smallest shrinkage.

The direction of least shrinkage is the direction in which the film travels (hereinafter abbreviated as MT) in the film pressing process.
Or, it occurs in a direction perpendicular to it (hereinafter abbreviated as TD).

To determine the heat shrinkage rate, cut out a square test piece with a side of 100 mm from the film, apply talcum powder evenly to both sides of the test piece to prevent it from adhering to other objects and receiving binding force during shrinkage, and adjust the temperature. After being placed in an air bath at 130°C for 5 minutes,
- Measure the distance L (mm) between opposing sides and find it using the following formula:

Usually, one side of the test piece is parallel to MD, and the other side is T.
I), and determine the heat shrinkage rates in both MD and TD directions.

The heat shrinkage rate is a measure of the stretching orientation dust of the film, and is preferably 40 to 80%.

Films with a heat shrinkage rate of less than 30% will cause necking when stretched, and especially for stretch packaging films, wrinkles will appear on the film after packaging, and areas with discontinuous transparency and gloss will occur. This results in an extremely unsightly appearance, making it difficult to put it to practical use.

Heating shrinkage rate 3()%, +: low stretching resistance =
Noi 7L・l・ has zero drawbacks such as low tensile strength and impact strength, and the film tends to break during stretch wrapping.

In addition, a film with a heat shrinkage rate of 80% or more has a high degree of stretch orientation, which causes a decrease in film elongation at break, a decrease in tear resistance against notches, and tearing during heat sealing, which tends to be undesirable as a film for stretch packaging.

The elastic recovery rate is a value measured in accordance with ASTM D-412-68T, and an elastic recovery rate of 60% or more means that it is 60% or more even in the smallest direction, preferably 70%. That's all.

The direction of least elastic recovery usually occurs in M II) or TD.

The elastic recovery rate is determined by the width 1 parallel to the MD and TD of the film.
0 mm, length] -00 mvt test piece is cut out, and a marked line is marked at a position of 25 mm from the center to both ends.

This test piece was pulled with a normal tensile tester at a speed of 200 mm for 1 minute until the distance between the marked lines was 100 mm.
Hold for a minute.

After that, the iron piece was tested in a short cycle and loosened until the 6-tension stress applied to the iron piece became zero, and then quickly removed from the 0-tension tester and left for 60 minutes.

After standing, measure the distance L (mm) between the marked lines and find it using the following formula.

Films with an elastic recovery rate of less than 60% are used in stretch packaging to wrap items of different shapes and sizes, so they can withstand wrinkles due to large elongation that occurs locally and a decrease in force after being stretched. It returns to its original state without leaving any residue, making it difficult to maintain sufficient tension, and the appearance of the package becomes unsightly.

Furthermore, when packages are stacked in several layers for storage, displayed at a store, or when the film is pressed with a finger when taken out, the film surface deforms and wrinkles occur. The product does not disappear and reduces the commercial value of the packaged product.

Anti-fogging property is necessary to prevent the film surface from becoming cloudy and opaque due to water droplets when the packaged item contains water or is stored at low temperature, making it impossible to see through the packaged item and reducing the product value. 20 containing 100ml of water at 20℃
The film of the present invention is one in which a film is placed in a beaker with a capacity of 0 ml, and the film is left in a constant temperature bath set at 5°C for 10 minutes, and then taken out, and the state of adhesion of water droplets on the film surface is judged with the naked eye according to the following criteria. The physical properties were measured after the film was manufactured and stored in a constant temperature room at 23°C and 50% humidity for 10 days.

Further, the film of the present invention preferably has the following physical properties.

Roll peeler, that is, after winding up 1.00 m into a roll with a winding tension of 509/cyn (per film) and storing it, the force required to pull it out at a speed of 60 cr I'L/min divided by the film per inner part is 7 g. /crrL or less, preferably 6 g/cm or less.

If this value is large, the film surfaces may lock together when the film is stored for a long time or in a relatively high temperature place, or when the film is pulled out from the roll.
Problems arise such as the film being stretched and permanently deformed, and the film being more difficult to pull out than a hunt wrapper, resulting in poor packaging workability.

In addition, when used as a stretch packaging film, especially for manual packaging, it has a breaking elongation of at least 100%, preferably 200% or more, 1 to 5 to 9/m'rlL.
s Preferably a breaking strength of 1.5 to 5 kg/ma, especially a tensile load at 200% elongation of 100 to 5009/cr
n (per film), preferably 150 to 4009
/crn1, more preferably 200 to 350 g/cm.

In order to tightly stretch-wrap various items, it is necessary to stretch the film to fit the size and shape of the item, and the problem is that the film may tear or break when stretched. Appropriate strength is required to prevent the film from deforming, and the tensile load at 200% elongation is necessary to ensure that the film is evenly stretched and that the film is wrinkle-free and has good tension.

Note that the tensile test mentioned here was measured at a tensile speed of 200 mm/min according to the method of JIS Z1702.

Furthermore, lubricants such as polyethylene glycol, polypropylene glycol, and paraffin wax, pigments, dyes, and the like may be added within a range that does not impair the characteristics of the present invention.

As described above, the film of the present invention uses a mixture of tackifying resin and mineral oil to internally plasticize and soften EVA to improve its self-adhesiveness, and also to remove the mineral oil that bleed onto the surface. The ionic surfactant improves the adhesion between the film and other objects, and the layer of mineral oil and nonionic surfactant acts like a lubricant to reduce the frictional resistance on the film surface. In other words, it has the characteristics of a low coefficient of dynamic friction and high self-adhesiveness, which were not available with conventional films.
Furthermore, as mentioned above, the film has excellent optical properties, such as transparency and gloss, due to the mineral oil inside or on the surface, and has anti-fogging properties due to the action and effect of the nonionic surfactant. .

Next, a method for producing the adhesive packaging film of the present invention will be explained.

The EVA composition used in the present invention described above can be prepared by preparing a masterbatch of each additive and blending it to a predetermined amount, or by preparing a masterbatch of a mixture of the three additives in a predetermined amount. Either the additives are prepared, blended to a predetermined amount, and fed to the extruder, or a predetermined amount of a mixture of three types of additives is heated at a constant voltage through a liquid inlet provided in a part of the cylinder of the extruder. The mixture is blended by injecting a predetermined amount using a pump and kneading at the same time as extrusion, and then extruded through a die with an annular slit installed in an extruder at 140 to 250°C to form an extruded tubular membrane. The outer circumference is cooled with liquid to rapidly solidify the tubular membrane to obtain the original fabric.

In the above, the inventors have explained that the tackifying resin used in the present invention, particularly the alicyclic saturated hydrocarbon resin, aliphatic hydrocarbon resin, etc., is added to a mixture of mineral oil and a nonionic surfactant, for example. We have discovered that it has the property of melting at a temperature of 100°C or higher, and that the tackifying resin does not precipitate even when cooled to room temperature, which is one of the properties of this additive. By the method of simultaneously performing extrusion and kneading by injecting additives using the metering pump described above,
This makes it possible to uniformly disperse additives, simplify the manufacturing process, and improve economic efficiency.

In addition, the temperature of the EVA composition extruded from the die is 14
If the temperature is below 0°C, the extensibility during melting will be poor and it will be difficult to form a tubular film, and the surface of the resulting raw film will be rough, resulting in poor phosphorescence and gloss, and the optical properties of the film after stretching will be poor. This results in deterioration of characteristics.

Moreover, if the temperature exceeds 250°C, it is undesirable because it promotes gelation and decomposition of EVA and causes decomposition and deterioration of additives.

Cooling and solidification of the extruded tubular membrane by means of a liquid surrounding the outer circumference of the tubular membrane is one of the useful methods for obtaining the film of the present invention. It is cooled and solidified by casting a liquid layer around the outer circumference of the membrane.

In particular, a method of forming a liquid layer that is cast around the outer circumference of the tubular membrane is preferred, and water is usually used as the liquid.

According to the method of this invention, the raw fabric that is rapidly cooled and solidified with a liquid has a smooth surface, resulting in a raw fabric with excellent optical properties, and has advantages such as extrusion stability of the tubular film and prevention of blocking on the inner surface of the raw fabric. It has the following.

Next, the obtained raw fabric is heated to a predetermined temperature uniformly from its outer circumference, expanded to a predetermined diameter, and stretched appropriately in two directions, vertically and horizontally, to uniformly blow air from the circumferential direction. After being cooled and solidified by spraying, the film of the present invention is obtained by continuously nipping it with nip rolls and winding it up with a winder.

゛Here, the temperature at which the original fabric is heated for stretching is 70 to 140°C, preferably 80 to 130°C.

This temperature is important regarding the stretching effect, the stretching ratio,
Heat shrinkage rate, optical properties and EV that indicate the degree of orientation
Although it is complicatedly related to the type of A, processing stability and optical properties deteriorate at low temperatures, and melting of the original fabric and a decrease in the degree of orientation occur at high temperatures, so in this invention, the above range is It is appropriate.

Further, the stretching ratio is such that the area stretching ratio is 50 times or less, preferably 40 times or less, and the lateral stretching ratio is 3 to 9 times, preferably 5 to 8 times.

Note that the area stretching ratio indicates the longitudinal stretching ratio x the horizontal stretching ratio.

By appropriately stretching the film of the present invention, the elastic recovery properties and strength of the film can be improved, and a film particularly suitable as a stretch packaging film can be obtained.

As described above, the film of the present invention is made of the EVA
The composition is extruded through a die having an annular slit, the original fabric is rapidly cooled and solidified with a liquid, and then reheated to a temperature of 70 to 1400C, and the area stretch ratio is 50 times or less and the transverse direction stretch ratio is 3 to 9 times using the inflation method. It can be suitably obtained by a manufacturing method characterized by stretching the film so that it becomes .

Examples will be described below, but the invention is not limited thereto.

Example 1 From a 50 mm diameter annular die having 0 and 5 □□□ slits provided at the tip of a 45 mm diameter extruder, Tables 1 to 4
The EVA composition shown in Table 5 selected from the EVA and additives shown in the table (additives used were masterbatches prepared in advance) was extruded at a maximum temperature of 190°C in the cylinder part and a temperature of 180°C in the die part. A ring is extruded downward at a machine rotation speed of 65 rpm, expanded so that the ratio of the diameter of the die to the diameter of the tubular membrane is 1.3, and has a slit on the inside where water comes out at a position approximately 20 crIL from the die tip. The tubular membrane was brought into contact with water at a temperature of 15° C. for 411 minutes so as to surround the tubular membrane, and was cooled and solidified.

This tubular membrane was pulled into an original fabric using nip rolls at a pulling speed of 3.5 m/min so as to have a folding length of 100 mm and a thickness of 350 μm.

The obtained original fabric was passed through a heating cylinder equipped with a circular infrared heater, and heated to 110°C for A4, A7, A15, and boiling 16.
Other than that, heat it to 130℃,
Inflate it by putting air in it so that it doubles in size, and then cool it evenly with air from the outer periphery using an air ring to make it 18cm thick.
A film with a diameter of 650 mm during folding was taken up with a nip roll at a take-up speed of 1 o, sm/min, and the edges were slit to make a film with a width of 30 cm, which was peeled into two pieces and wound up into a roll.

Table 6 shows the physical properties of the obtained film.

Manual packaging machine (Hunt wrapper F W4 manufactured by Nippon Sangyo)
6-B model) was used to package items containing 200 gr clay plates in a tray (DH-200 model manufactured by Nippon Dixie).As a result, all of the packaging was in good wrapping condition with no wrinkles in the film. I got something.

Self-adhesiveness in Table 6 means that in the above packaging test, after stretching the film, the edge of the film was bent to the bottom of the tray, and the bottom of the tray was left facing up for 10 seconds, and the edge of the film peeled off. The self-adhesive property shown below is a fundamentally important property for stretch packaging films, and the peel height 2
If it is 0 mm or more, the elastic recovery force of the film will cause the stretched film to loosen between the time when the film ends are clinched after stretching and the time when the film ends are welded and fixed by heat sealing, resulting in wrinkled tension. This results in a weak packaging condition, which significantly reduces the commercial value of the packaged product.

Example 2 Using the A5 EVA composition of Example 1, the amount of air in the bulb during stretching was adjusted, and the stretching ratio in the lateral direction was adjusted to 1.
7 was swollen to 3.0 times, A18 was swollen to 5.0 times, and A19 was swollen to 7.5 times to obtain a film with a thickness of 18 μm.

The thickness of the original fabric is 165μ for A1.7 and 2μ for A1.7.
The heating temperature of the film 6 during stretching was 110°C for A17 and 120°C for Boiled 18.
, Boil 19 was set at 140°C.

Table 7 shows the physical properties of the obtained film.

Stretch wrapping was carried out in the same manner as in Example 1. Although small wrinkles appeared on the film surface of the 116 and 1.6 films, they could be wrapped with almost no problems, and the other films were also wrapped in good condition almost the same as in Example 1. It was in a packaged condition.

Comparative Example 1 The A5 EVA composition of Example 1 was applied through a 100 mm diameter annular die with 0.4 mm slits provided at the tip of a 45 mm diameter extruder at a maximum cylinder temperature of 19 mm.
The air is extruded downward at 0°C and the goo part temperature is 200°C, inflated so that the ratio of the diameter of the die to the diameter of the tubular membrane is 2.5, and has an annular slit inside at a position approximately 3cm from the tip of the die. Air at 23°C was blown for 0.77117 minutes from the ring, and water at 21°C was blown at 81°C through a ring having an annular slit at a position approximately 27 CrrL from the die tip.
The tubular membrane was brought into contact at a rate of 3/min to surround the tubular membrane, and the tubular membrane was cooled and solidified to obtain a film having a thickness of 18 μm and a width of 30C111.

This film has a dynamic friction coefficient of 0.25, a haze level of 1.6, a heat shrinkage rate MD of 61%, a TD of 14%, and an elastic recovery rate MD
was 61% and TD was 39%, indicating that the film had good anti-fogging properties and self-adhesive properties; however, when it was stretch wrapped in the same manner as in Example 1, necking
n/ Jx robe i″: JL,] E>#z,
The product was packaged in a loosely packed state with a large amount of jHj (11 due to poor recovery characteristics, etc.) in the packaging.

Furthermore, since the film was not stretched and pressed like the film of the present invention, it lacked strength, and the film was observed to break due to the edges of the tray.

Comparative Example 2 A film consisting of an EVA composition shown in Table 8 containing a combination of one or two additives among the additives used in the present invention was obtained in the same manner as in Example 1.

The heating temperature during stretching was all 130'C.

However, A27 was originally filed by the inventors in Japanese Patent Application No. 49482.
This is a film found in No. 80 that is particularly suitable as a trench packaging film for Isogi packaging, and is in comparison with the film of the present invention.

Note that PEG-300 used in A29 in Table 8 is polyethylene glycol with an average molecular weight of 300.

The properties of the obtained film are shown in Table 9.

Tackifying value of Arashi 2O-A22: Films with 1 fat of Zchi added have extremely high dynamic friction coefficients of 1 to 1 or cannot be measured, and a blocking phenomenon occurs in rolled films. However, the film was completely unusable.

Furthermore, when the surface of the film 18 was rubbed with a finger, the trace became whiter and the transparency of the film was significantly reduced.

When a trench packaging test was conducted on the film of &20 in the same manner as in Example 1, it was found that the film had poor lubricity with the guide rolls of the packaging machine, and the roll peeling was large.
The film cannot be pulled out at the edge of the tray, and the slipperiness with the edges of the tray is low, so it cannot be stretched sufficiently, resulting in a wrinkled and loose packaging. A phenomenon occurred in which the metal was broken.

In addition, in the films of Arashi 23 and Gan 24 to which only mineral oil was added, the surface of the 1' lumen was so sticky that the coefficient of dynamic friction was unmeasurable, and the self-adhesion was also poor.

The coefficient of dynamic friction could not be measured for Ai: 25 and A26 films containing adhesive copying resin and mineral oil, and the roll peeler was rather large, making it difficult to pull out the film smoothly. It was bad.

None of the films No. 20 to No. 26 had antifogging properties.

Arashi 27, A28 adhesive resin and non-ionic field [1
t'l-! r divination V-k "jl;')") f-4
q y,;,7-7,r,71/7,(1,7
A, /lz j, A, uei h (The film has a poor appearance, with whitish white flag-like contamination on the surface of the film, and furthermore, the marks from rubbing the film surface with fingers are even more whitish. It was a film that had some problems.

Furthermore, since the roll peeler was large, it was difficult to pull out the filtration smoothly from the roll, and the film had a poor self-adhesion t'+.

Arashi 29's film had a low coefficient of dynamic friction and roll peeling, allowing the film to be pulled out smoothly from the roll, and was excellent in continuous packaging. (Kokling (2 times until heat sealed...) nun
(?:, Fufui/!, Mu (so) Al, cow F group jjl
(Teyo () - Noi) Phenomena of loosening of the shims, wrinkles, and weakening of tension were observed, and the film had problems in terms of self-adhesion when used with manual packaging filter binding.

Claims (1)

[Scope of Claims] 1. A weight coefficient graviolene-vinyl acetate copolymer with a melt index of 0.5 to 20 and a vinyl acetate group content of 5 to 40, an alicyclic saturated hydrocarbon resin, and an aliphatic hydrocarbon. resin,
Adhesive Fj-resin selected from petroleum resins, sticky polypropylene resins, rosins, and polyterpenes 0.5~
5 wt. A stretched adhesive packaging film characterized by having an elastic recovery rate of 60% or more and antifogging properties. 2 Melt index is 0.5-20. A weight coefficient quantum ren-vinyl acetate copolymer having a vinyl acetate group content of 5 to 40, an alicyclic saturated hydrocarbon resin, an aliphatic hydrocarbon resin,
A tackifying resin selected from petroleum resins, harsh polypropylene resins, rosins, and polyterpenes, 0.5 to 5 weight parts, mineral oil 1 to 10 weight parts, and a nonionic W surface active agent 0.1 to 5 weight parts. A resin composition having a weight of φ is melt extruded through a die having an annular sulin 1 or more, and the original fabric is rapidly cooled and solidified with a liquid and then reheated to a temperature of 70 to 140°C, and the area stretching ratio is 50 times or less by an inflation method. A method for producing a stretched adhesive packaging film, comprising stretching the film at a stretching ratio of 3 to 9 times in the transverse direction.