JPS5867450A - Polyamide group laminated heat-shrinkable 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 relates to a boria-doped yarn seed layer heat-absorbing film having a high practical llff1 value and exhibiting a high heat absorption rate IIa with a well-balanced length and width, and a method for producing the same.

Conventionally, polyamide resins such as nylon-6 have been widely used as packaging upper films due to their excellent physical properties such as pinhole resistance and oil resistance, but they have the disadvantage of high moisture permeability and poor heat sealability. Therefore, it is not necessarily suitable as a packaging material when used alone.

In order to improve this drawback, it is common to use a polyamide resin and a polyolefin resin with heat-sealing properties in a layered manner. These are used as polycladding materials.

However, polyamide resin and polyolefin 4! It is very difficult to industrially produce a stretched film with a coextrusion layer of polyamide resin and a resin. It is manufactured by coating a heat-shrinkable polyamide film with a resin solution such as vinylidene chloride, as shown in , or by extrusion laminating a polyolefin resin on a heat-shrinkable polyamide film, as shown in Utility Model Publication No. 39-10894. It is common to

Polyamide-based laminated heat-shrinkable films produced by these coatings or extrusion laminations The heat-shrinkable polyamide film shrinks due to the heat applied during Atf coating or extrusion lamination, causing wrinkles, sagging, and sagging. The disadvantage is that a laminated film with high heat shrinkability cannot be obtained because the original heat shrinkability is reduced and the heat shrinkage of the polyamide film is inhibited due to the moisture content. .

Therefore, it is expected that if an unstretched film laminated with a polyamide resin and a polyolefin resin is stretched, high heat shrinkability will be imparted to the film in which both are oriented at the same time. -No. 92882 and 41st Association 1982-
Attempts have been made to obtain heat shrinkable films by stretching unstretched films laminated by extrusion or coextrusion, as seen in No. 48896.

In JP-A No. 51-92882, a coextruded laminated film having a coextruded shape is subjected to Chebura stretching through a heating bath at a temperature below the secondary transition point of nylon (65.6°C), preferably 48.9 to 60°C. Although high orientation can be obtained, there is poor adhesion between the polyamide and polyolefin layers.
Even if you use fat, it will not stretch. I'm tired of getting a relatively thin film.

In addition, the method disclosed in Japanese Patent Publication No. 55-4:1s89fs is a method of sequentially biaxially stretching a coextruded laminated film. 6 or nylon-66
It is difficult to use such homopolymers as polyamide layers.

As a result of intensive research to improve these drawbacks, the inventors of the present invention have developed polyamide resins and polyolefins using a four-way biaxial stretching apparatus using the two-way chain method. A polyamide heat-shrinkable polyamide film N1 having good interlayer adhesion and high heat-shrinkability was obtained.

Namely, the present invention is (1) a laminated heat-shrinkable film comprising a polyolefin-based blended composition and a polyamide-based blended composition as laminated constituent layers, the laminated constituent layers being nylon-6, nylon-silver, and nylon-610.゜Polyamide blend composition consisting of Daiylon-612, Nylon-11, Nylon-12, or a copolymer or blend of two or more of these. Intermediate layer Q low-density polyethylene, edge-shaped low-density polyethylene, +1
61t & polyethylene, ethylene-α-olefin copolymer, polypropylene, ionomer resin, ethylene-
It consists of three layers of a polyolefin compound composition made of a polyolefin synthetic resin made of vinyl acetate copolymer or a blend of two or more of these, and the dimensions after immersing it in hot water at 100°C for 80 minutes. A polyamide-based laminated heat-shrinkable film 2 with good heat-shrinkability characterized by a yield rate of 2 (over 14) in both the vertical and horizontal directions. 612, nylon-11, nylon-ν, or a copolymer or blend of 2fI or more of these. Layer a. Main component is a grafted polyolefin obtained by graft polymerization of a radically bundling unsaturated compound. Intermediate layer Q consisting of a resin composition of low-density polyethylene, linear low-density polyethylene;', +
A polyolefin compound consisting of one polyolefin synthetic resin such as AfiJi polyethylene, ethylene-α-olefin copolymer, polypropylene, ionomer resin, ethylene-vinyl acetate copolymer, or a blend of two or more of these resins. An unstretched laminated film obtained by cooling a coextruded II melted chape consisting of three composition layers was introduced between low speed and high speed nip rolls so that the film surface temperature at the stretching part was in the temperature range of 60 to 100 ° C. By adjusting the pressure of the gas supplied to the inside of the tubular body and the peripheral speed ratio of the low speed and high speed nip rolls, simultaneous biaxial stretching is carried out by 2 to 5 times in both length and width.
This is a method for producing a polyamide-based heat-shrinkable film having good heat-shrinkability.

The polyamide blend composition used in the present invention utilizes excellent gas barrier properties and toughness, and is made of nylon.
6. Nylon-6I3. Nylon-MO.

Nylon-612, nylon 5'-11, nylon-612, nylon-612, or a copolymer of 2al or more thereof consists of a blend. Well-known lubricants, modifiers, etc. can be added to these bolioid-based and blended compositions.

In addition, the adhesive upper resin used for the intermediate layer is maleic acid, 7
Unsaturated organic acids such as malic acid, itaconic acid, acrylic acid, methacrylic acid, crotonic acid, etc., and radically vertically unsaturated compounds of these acid anhydrides, esters, r-amides, etc., and polyolefins. The type of polyolefin is not particularly limited, and may include polyethylene, polypropylene,
A polyolefin-based blended composition with a copolymer such as a bait-vinyl acetate copolymer takes advantage of its excellent heat-sealability when molded into packaging bags, etc., and has a low density. Polyethylene, Is-like low density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, polypropylene.

Consists of a blend of seeds or more. Known antistatic agents, lubricants, etc. can be added to these polyolefin compound compositions.

The laminated film of the present invention has a three-layer structure of polyolefin blend composition/grafted polyolefin/polyamide blend composition.

A polyolefin resin may be further laminated on the outside of the polyamide compound composition or the polyolefin compound composition to form a structure of four or more layers.

As methods for laminating, dry lamination, extrusion lamination, coextrusion, etc. are known.

A multilayer plastic gourd having a nine-layer structure in which the polyolefin blend composition layer, the adhesive grafted polyolefin resin layer, and the polyolefin blend composition layer are adjacent to each other in this order is melt-extruded from a laminated goo using a coextrusion method. The film was then cooled and solidified, and then the film surface in the stretching zone was heated to a temperature of 60 to 100°C using a double-branch simultaneous biaxial stretching device.
The film is characterized in that it is reheated with an infrared resistant heater so as to have f1f@, biaxially stretched 2 to 5 times in length and width at 11:00, and then cooled with cold air or the like. In this case, the film surface temperature of the laminated film in the stretching zone is set so that it is above the β-las transition point of the polyamide blend composition and below the melting point of the polyolefin blend composition, preferably in the range of 60 to 100°C. Heating is necessary.

If the film surface temperature in the stretching zone is 60° C. or lower, the polyamide compound composition may be stretched too thin or the adhesive strength of the m-layer may be significantly reduced, making it difficult to increase the stretching ratio as desired. On the other hand, when the surface temperature of the film in the stretching zone exceeds 100°C, the strong V of the polyolefin blend composition layer decreases, making it easy to puncture and causing the tubular body to deteriorate. Stability also deteriorates. Furthermore, since the polyolefin blend composition layer is in a molten state, the thickness deteriorates, and furthermore, sufficient orientation cannot be obtained, so that a useful film with high heat shrinkability cannot be obtained.

Also, stretching 11! The I ratio can be selected according to the required heat shrinkage rate depending on the application, but in order to use it for ordinary heat shrinkable film applications, it is preferable to stretch it twice or more in both length and width. It is preferable to stretch the film by a factor of 2 times or less because it can be stably stretched.

For this reason, annealing at a predetermined temperature is required.By using this crystal production method, a person can be placed in hot water at 100℃ for 80 minutes.
It is possible to obtain a polyamide heat-shrinkable laminated film having a dimensional shrinkage rate of 209b or more in both length and width after 10 minutes and a small natural shrinkage. O A heat-shrinkable laminated film with a total thickness of 10μ or more can be easily produced by the method of the present invention. 6 pieces thickness 100μ
The thickness of the adhesive Im fat layer is about 5 to 50 mm with respect to the polyamide compound layer, and the thickness of one corner of the polyolefin compound layer is 5 to 80 mm.
O is preferably about 0% Heat-shrinkable area of the present invention 1-The film has flexibility,
Excellent pinhole resistance and heat sealability.

1. Meat and processed meat products with favorable low-temperature shrinkability.

Suitable for storing and packaging foods such as pickles ◇1 The film surface temperature of the thermocouple is covered with aluminum foil to avoid the effects of radiant heat from the debris.2 Thickness and diameter approximately 1++ m
Heat was applied to the film surface using a surface thermometer (manufactured by Anritsu Keiki@, model HP-4F2) connected to a chromel-constantan type thermocouple (45 Ω) with a diameter of approximately 15 m, and the tip was brought into contact with the film surface for 80 min. The temperature of the film surface was determined by the indicator after a few seconds.

2 A film cut into a square with a hot water shrinkage rate of 111α in both length and width is 100
It was immersed in water for 80 minutes and calculated using the quadratic formula: 10 - A x 100 = hot water shrinkage W - 1 O, where A is the length of one side after immersion (in units of country).

Examples 1 to 6 A Kieler die is put into three 40 mm diameter extruders to form an inner layer of a polyamide compound composition, an intermediate layer of a grafted polyolefin composition, and an outer layer of a polyolef compound composition of 1). do it like this.

The obtained thin-substrate laminated unstretched original fabric was introduced between two pairs of nip rolls, heated with an infrared heater, and air was blown into the inside, and the size was increased by 8 times by 8 times depending on the circumferential speed ratio of the nip rolls and the internal pressure of the air. Simultaneous biaxial stretching was carried out using two methods. Table 1 shows the results obtained by adjusting the voltage applied to the infrared heater and observing the film surface temperature and stretch state at that time.

[Left below] Here, Ny-6... Nylon-6 (Example) Nylon-61022BNy-3fi manufactured by Ube Industries, ...
,, , Nylon-Seki (Example) Nylon-66 manufactured by Ube Industries
20268Ny-9/f56 Copoly・・・・・・
...Nylon-6/66 copolymer (example) Copolymerized nylon 5038 manufactured by Ube Industries Co. Example) Mitsubishi Oil Membrane Mcxlic E-1oo) ((Example)
Mitsui Oil Engineering tMA-dmer VF 500LDPE
・・・・・・・・・Low density polyethylene (example) Nippon Unicar NUC8008gVA ・・・・・・・・・
- Ethylene-vinyl acetate copolymer (example) Evatate D2011 ionomer manufactured by Sumitomo Chemical Co., Ltd. Ethylene-methacrylic acid copolymer Zn type (example) Mitsui Polychemil Chikuruhimilan 1652.

Table 2 shows the results of measuring the hot water shrinkage rates of a shrinkable nylon-6 film and a heat-shrinkable nylon-6 film laminated with low density polyethylene by extrusion.

Table 2 A laminated film (Comparative Example 2) in which low-density modified polyethylene is extruded and laminated to heat-shrinkable nylon-6 film A (Comparative Example 1), which has relatively high hot water shrinkability, has a significantly reduced hot water shrinkage rate. In contrast, it is clear that the laminated heat-shrinkable film of the present invention has a greatly superior hot water shrinkage rate. Also, using the extruded laminate film of Comparative Example 2 and the present invention film of Example 4, 1 batch of roasted duck thigh meat was prepared and treated with hot water for 10 minutes in an autoclave illuminated with hot water at 105°C. Although the film of Comparative Example 2 did not adhere tightly to the meat in some places due to insufficient shrinkage, the film of the practical example adhered tightly despite the uneven shape and showed a packaging state with no wrinkles. .

Patent applicant: Kojin Co., Ltd.

Claims (1)

[Scope of Claims] 1. A laminated heat-shrinkable film comprising a polyolefin blend composition and a polyamide blend composition as laminated constituent layers, the laminated constituent layers being nylon-6, nylon-silver, nylon-6. 610, nylon-612, nylon-U
. Polyamide compound composition layer a consisting of nylon-12 or a copolymer or blend of 211 or more of these; consisting of a resin composition whose main component is a grafted polyolefin grafted with a radically polymerizable unsaturated compound; Intermediate layer C3 low-density vertical polyethylene, ll-shaped low-density positive polyethylene,
High quality vertical polyethylene, ethylene-α-offtwin copolymer, polypropylene. It consists of three layers: an ionomer resin, a polyolefin synthetic resin such as ethylene-acetic acid beer copolymer, or a blend of two or more of these. A polyamide yarn with good heat shrinkability characterized by a dimensional yield S rate of over 20% in both length and width after 80 minutes of human application. -66, nylon-610
, nylon-612, nylon-11゜nylon-12
or a polyamide compound composition 1-B consisting of a copolymer or blend of two or more of these, a resin whose main component is a grafted polyolefin obtained by graft polymerizing a compound to a radically polymerizable unsaturated a. Intermediate layer consisting of a composition C6 low density polyethylene, @-like low'me polyethylene,
, % density polyethylene, ethylene-α-olefin copolymer, polypropylene. Cooling a coextrusion melt chip consisting of three layers of a polyolefin compound composition made of an ionomer resin, a polyolefin synthetic resin represented by ethylene-vinyl acetate copolymer, or a blend of two or more of these. The unstretched laminated film obtained by A method for producing a polyamide-based laminated heat-shrinkable film with good heat-shrinkability, characterized by simultaneous two-wheel stretching of 2 to 5 times in the length and width by adjusting the pressure and peripheral speed ratio of low speed and high speed nip rolls0