JPS58116149A - Heat-shrinkable laminated film - 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 has a gas barrier layer, both outer layers made of a super fat having heat resistance V, and at least one layer of soft vinyl chloride resin l. The present invention relates to a heat-absorbing film that is excellent in 4I.

Many fatty foods such as raw meat and processed meat are irregular in shape and size. In this way, heat absorption 111!10 film! Shrink wrapping is widely used industrially. The general procedure for this method is to first put the contents into a bag-shaped film, and then tightly pierce it with a vLWM mouth part Y mouth part and heat seal assembly, which removes the air inside the film under reduced pressure. This is then guided through a heating device such as a hot water path or a hot water heater, and the film is heat-shrinked.At this time, the contents are often heat-treated to also sterilize them.

In the process of such packaging operations, the film is exposed to heat and fat.
The bulge may be thinly stretched locally or, in extreme cases, may be damaged.
In addition to the physical properties required for general packaging films, films for this purpose are strongly required to have oil resistance and heat resistance in addition to the physical properties required for general packaging films.

These physical properties depend on the material of the film, but also on the uniformity of the thickness of the aK film, so a film with as uniform a thickness as possible is required.

However, as a thermal ah film with sparring properties, chloride/=l
It is called PVDO. ) single film, a laminated film of ethylene-vinyl acetate copolymer (hereinafter referred to as mvmu) and PVDO (hereinafter referred to as IVA/PVDO/I [lVA film) in Canadian Patent No. 982923, 4IS#! 111-shaped polar layer film of 111-shaped MV, PVDO, and irradiated icv, ionomer resin, ethylene vinyl alcohol copolymer (hereinafter F
There is a polar layer film of BVA (referred to as it-OH).

Depending on the type of food being packaged, additives such as plasticizers and stabilizers may migrate into the food and may be unfavorable from a sanitary standpoint, or a relatively large amount of additives may be required to maintain the side group strength V. There are drawbacks such as a decrease in the properties of the food, making it unfavorable for food storage, and the inability to heat-seal the food.

EvA/PVDO/IVA 8 layer film is EV
AY JP-A-47-34 using EVA 'lp for outer layer
In the method of No. 565, the crosslinking of the inner and outer layers is performed by PVD of the core layer.
It is not carried out because decomposition of O occurs. Japanese Unexamined Patent Publication 1973-
The laminated film in No. 89944 is co-stretched with the LCT-OH ionomer resin, which limits its stretching and makes it difficult to obtain a film with a uniform thickness. This is one of the reasons why it is not possible to do so. For this reason, there has been a demand in the food packaging field for a heat-shrinkable film with good oil resistance, heat resistance, and spalling properties and good stretchability.

In order to obtain a film V having excellent oil resistance and heat resistance, it is preferable to use a resin having a crystal melting point of 110 DEG C. or higher, such as an a-olefin polymer or a boria-density copolymer, in the outer layer.

However, resins with a crystalline melting point of 110° C. or higher have poor stretchability and cannot be easily and uniformly stretched when laminated with a spaller layer, making it difficult to obtain a heat-shrinkable film V.

As a result of intensive research, the inventors found that by adding at least one layer of soft vinyl chloride resin 11i (hereinafter referred to as soft 1'pvo) V to the structure of the heat-shrinkable film, the stretchability can be significantly improved. An object of the present invention is to provide a heat-shrinkable film V which has excellent oil resistance and heat resistance and which can be uniformly stretched without causing local minute necking.

The heat-shrinkable laminated film of the present invention has an adhesive layer and both @V
11i layered gas barrier, specific gravity 0.900~0
．． Ethylene and α-olefin copolymer (1) having a crystalline melting point of 110 to 130°C at 950° C. Outer layer (A) consisting of a mixture of copolymer (1) with 80 Ftls or less, 1 copolymer of ethylene and α-olefin (11, 1 copolymer of ethylene and α-olefin)
an outer layer consisting of a resin selected from a mixture of 1120 mm or more and the ethylene-vinyl acetate copolymer (1) 80 mm or less;
B) Contains V and has at least one soft vinyl chloride pattern fat layer between the outer layer and the core layer! &s/#yr.

The present invention will be explained in detail below.

The outer layer (A) of the present invention is ethylene-α having a low crystalline melting point.
- Since it is a mixture of an olefin copolymer or the ethylene-α-olefin copolymer and InVA, it has heat resistance,
It is oil-based and contains resin with a high crystal melting point.
Good stretchability.

In the present invention, an ethylene and α-olefin copolymer (11 is ethylene and a small amount of butene-1,
Pentene-1,4-methyl pentene-1, hexene-
1, a copolymer with an octene-1 α-olefin having 18 or less carbon atoms is used. Examples of these copolymers include so-called Linear copolymers such as Ultzex and Neozex (all manufactured by Mitsui Petrochemical Co., Ltd.), G-Resin (manufactured by Union Carbide), and Dowlex (manufactured by Dowke Cal).
LOW Density Polyethylene (
J-1 lower LLDPFi and the ratio called 10.90
0 to 0.950 and a crystal edge point of 110 to 160°C is used.

These must be added to the outer layer (-) at least 2011-.
1 oiliness does not increase by 1ijl. Also, the temperature of 85-103℃
LMAI' has an Evum (seal) containing vinegar and vinyl 1
3 to 121 tilil-.

These crystal melts and ashes were measured using a differential scanning calorimeter (IJ manufactured by Pern. Elmer) using a sample 8.
This is the maximum -Y temperature of the melting curve measured in minutes.

In the present invention, the PVDO used in the gas barrier layer is a copolymer consisting of 65 to 95 weight vinylidene chloride and at least one kind of Hiko unsaturated monomer copolymerizable with the vinylidene chloride. be. Examples of unsaturated monomers that can be co-headed include vinyl chloride, acrylonitrile, acrylic acid alkyl esters (alkyl 118 number 1 to 18
M) 41! can be given. Among these, vinylidene chloride-vinyl chloride monomer is common. In this vinylidene chloride resin, known plasticizers, stabilizers, etc.
Can be added.

Moreover, It-OH is a partially saponified resin consisting of ethylene and vinyl acetate, and those having an ethylene content of 20 to 80 moles and a degree of saponification of 50 moles or more are used.

Ethylene-A tube olefin co-ml combined PVDO1j
! Since it -OH has no mutuality in nature, its laminate is likely to peel off. Also, soft 'J [PVO and PVDO, It −
Since the soft PVO contains plasticizer i between the OH and KIIk
Arrival K. Therefore, in the present invention, it is important to provide a hard adhesive layer at the interface between the two layers of the gas bag to prevent layer peeling. For the adhesive layer, carbon # and spastic polyolefin, ethylene and vinyl acetate copolymers, binary copolymers of ethylene and acrylic esters, methacrylic esters, etc., ternary comonomers with vinyl acetate, and styrene are used as adhesive layers. Nuptazoene block copolymer and the like are used. In addition, the contact agent J41fl can be used between '4M# as needed, especially when the soft PVO layer is stretched between both sides [preferably an adhesive layer is present]. It is extremely important to provide localized elasticity to the skin without causing irritation, and at least one
It is necessary that layers exist. The filling of the soft PVO layer is at least 6 μm in width to impart stretchability to the film.
The above is the summary.

The soft PVC used in this defense is '01
Is the amount of saponified polyvinyl chloride or its co-electrolyte V-f0 plasticizer added to 100 parts by weight of PVA? IL
20 to 80 iij parts is preferred. As the plasticizer, a known low-molecular 1-molecular plasticizer and a 9-molecular 01 Wi agent are used. Examples of low molecular weight plasticizers include polybasic acid aliphatic alkyl esters such as dioctyl adipate, zoctyl sebagate, and dibutyl sepacate, and phosphoric acid esters such as tricresol phosphate.
Orip ff with a molecular weight of 800 to 10,000 is used as a J plastic agent.
Examples include iriester oligomers containing dibasic acids such as azobic acid, sepacic acid, and azelaic acid and ethylene basic acids or alcohols.

Among these, those produced from aliphatic dicarboxylic acids whose alkyl groups have 6 to 10 carbon atoms and polyhydric alcohols whose alkyl groups have 2 to 6 carbon atoms have molecular weights of 1.000 to 3,000, especially 1.500 to 2.
,000 maryester oligomer f w - is preferably used.

Soft% PVC also contains additives such as stabilizers, lubricants, processing aids and colorants! It can be added as needed.

The outer layer ■) has a specific gravity of 0.900 to 0.950 and a crystal melting point of 1.
Ethylene and Ha-ole7ine copolymer (11) having a temperature of 10 to 130℃ and an ethylene and vinyl acetate copolymer (I1803Mi*υ below) with a crystal m1 point of 85 to 106℃ A mixture of the ionomer and the resin returned from the ionomer mallet is dyed.

Ionomer resins include ethylene, zolopyrene, olefin, acrylic acid, methacrylic acid, and maleic acid.
! Comonomer ion 61' with unsaturated carboxylic acid
Min'f Na", K", Mgox, Ca", Zn
Medium f with 4+ and other kai-ions! An ionic crosslinked product made of

When used as the outer layer (B) of ionomer resin, it has excellent sealing properties, so it is preferable to use it as the layer ([11]) in contact with the negative bond.

The polar layer film of the present invention is outer layer (B)/adhesive layer/soft PV
There are 7 narrow layers (O layer/7iit/to barrier/sliding layer/outer layer), but it is possible to add LL to the east and add each layer. The total thickness of the film is 20 to 12
0# is generally desirable.

The polar layer film of the present invention is extruded according to the number of polar layers, and the cylindrical one is extruded into a cylindrical shape using an annular dyne similar to JP-A No. 53-82888. The material is extruded into a flat shape using a known T-die Y and laminated. The cylindrical laminate is stretched by a biaxial inflation method according to a general method, and the plate-shaped laminate is stretched using a tenter to obtain a desired heat-shrinkable film.

The heat-absorbable stretched film obtained by the present invention has excellent oil resistance, heat resistance, sparring properties, and uniform thickness Y, and is suitable for packaging fatty foods that require high-temperature killing. used.

Examples will be described below, but the present invention is not limited to these examples as long as the invention is within the scope of the claims.

EXAMPLES A resin consisting of the polymers listed in Table 1 is extruded separately in several extruders and the molten material flows into a coextrusion annular die where it is formed into the required laminate.

The cylindrical body of the well log material flowing out from the die is cooled in a cooling tank at 15 to 25°C, and is flattened @120JlB and has a thickness of 685μ.
It is made into a cylindrical shape of ~555s. There is a V inside the cylindrical body in the cooling tank.
- Soybean oil was added to the four sides to prevent them from coming into contact with each other.

Next Vr, 14th vessel water oval yellow-! The cylindrical body is heated for about 12 seconds while rotating at a speed of 5 rotations/minute, and then returned to the cylindrical body with 1 nip a-lar V at a rotation speed of 511+/minute.

The thin body is rinsed at 15 times/min while being cooled with surrounding air at room temperature.
'''C age: fJp rotates once, and is sent into the cylindrical body while being stretched 3 times in the longitudinal direction until it passes through the 2nd nip roller Y. The first biaxially stretched film had a fold diameter of about 350 ml and a height of about 46 to 64 N.

Therefore, Table 1 shows the physical properties of the electric composite used in the VCvlL example, Table 2 shows the layer conditions of the 1Aj-film obtained in the example, Table 3 shows the physical property test method for the film, and Table 14 shows the properties of the film. Item b @ Th result is shown.

As is clear from Examples 1 to 6 in Table 4, the heat-shrinkable film of this issue also has excellent stretchability, has a sufficient heat yield ratio at 90°C, and has excellent oil resistance, heat resistance, and Good results were obtained.

P double trunk examples 1 to 6 do not have a soft PVO layer, and H
'Comparative Examples 1 and 6 could not be stretched. Comparative Example 2 could be stretched, but slight necking occurred and the stretchability was unstable.

Comparative Example 4 also did not have a soft PVC layer, and the first layer, which was the outer layer, was made of EiVA, resulting in unstable stretchability and poor oil resistance.

Agent Yoshio Kawaguchi

Claims (1)

Scope of Claims: (11fI layer, both 111v81 layers, Svalier grade Y core layer, ratio 1 of 0.900 to 0.950, and crystal fusion shield of 110 to 160°C V. Ethylene and α-olefin. 1 combination (1) or the co-1 combination (1) 20'M
III- or higher and crystal melting at 85-106°C
Silene and 1!1 vinyl acid copolymer (I180kii
The outer layer consists of Aimoku I with less than 1 (Al, ethylene and α
- 1-olefin combination (■), mixture of ethylene and α-olefin combination (1120184 or above and ethylene-vinyl acetate combination (I1801 + 1% J5), outer layer made of super fat derived from ionomer super fat) k (B)
A heat-converting laminated film comprising Y and a vinyl chloride resin layer existing between at least the first outer layer and the core layer and via the port layer Y. (Claim 21 is a heat-shrinkable laminated film according to item (1) of claim 1, in which 21 is a polyvinylidene-enhanced monomer or an ethylene-vinyl alcohol monomer. (3) Ethylene and a-olefin copolymer Combination (1) with ethylene -ff-1.pentene-1.◆Methylpentene-1, hexene-1, octene-1 to i!4#i
The claimed &
N II (No. 11 or No. 21) Heat-shrinkable laminated film according to Item 21.