JP3004418B2 - Processed meat packaging film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to hot water whitening, oil resistance,
The present invention relates to a processed meat packaging film having excellent meat adhesion. More specifically, the present invention relates to a processed meat packaging film comprising a composition comprising a specific ethylene ionomer resin and a polyamide.

[0002]

2. Description of the Related Art Processed meat, such as ham, sausage, bacon, and various cooked meat foods, is packaged in a film-like packaging material and supplied to the market. As these packaging materials, those used in the process of steaming may be used as they are, but in many cases, they are secondarily packaged after steaming or smoking. In any case, the plastic film used for such applications is required to have excellent transparency, heat sealability, food safety, oil resistance, and the like. Ethylene-based ionomer resins are widely used for packaging raw wood ham, sliced ham, and the like because of their excellent properties such as heat shrinkability and deep drawability of stretched products in addition to such properties.

[0003] For example, the packaging of a single piece of roast ham or boneless ham is described as a final product after vacuum-packing a smoked or steamed ham log with a composite film having an ionomer as an inner layer and lightly sterilizing it. At this time, if the shrinkage and meat adhesion are not good, floating occurs between the raw hamwood and the packaging film, and there is an inconvenience that the meat juice accumulates at the stage of distribution and storage. There is no. On the other hand, the conditions of the light sterilization are usually 80-100.
The treatment is carried out in hot water at a temperature of ℃ ° C., and the higher the temperature within this range, the more effective the treatment is in a shorter time, which is preferable from the viewpoint of productivity. In order to devitrify and degrade the commercial value, sterilization had to be performed at a slightly lower temperature.
If an ionomer or polyethylene having a low acid content is used, such a drawback can be avoided, but it cannot be said to be a preferable alternative material because of problems in oil resistance, heat shrinkability of a stretched film, and deep drawability.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present inventors
A study was conducted to find a packaging material having improved hot water whitening resistance without substantially impairing the excellent properties of the ionomer in processed meat packaging.

[0005] As a result, the object can be achieved by using a film in which a polyamide is blended with an ionomer of a specific property in which the type of cation and the degree of neutralization are selected,
In addition, the present inventors have found that they have the same or higher performance as ionomers in gas barrier property, transparency, meat adhesion, oil resistance, heat sealing property and the like, and have reached the present invention.

That is, an object of the present invention is to provide hot water whitening resistance,
An object of the present invention is to provide an ionomer film for processed meat packaging excellent in meat adhesion and oil resistance. Another object of the present invention is to provide an ionomer film for processed meat packaging excellent in heat sealability, transparency and safety.

[0007]

According to the present invention, an ethylene / unsaturated carboxylic acid copolymer having an α, β-unsaturated carboxylic acid content of 6 to 15 mol% is neutralized by a transition metal cation. A processed meat packaging film comprising an ionomer composition comprising 60 to 97 parts by weight of an ethylene ionomer resin having a degree of neutralization of 20 to 100% and 40 to 3 parts by weight of a polyamide.

The ionomer resin, which is one component of the packaging film of the present invention, has an ethylene / unsaturated carboxylic acid copolymer as a base polymer. As the unsaturated carboxylic acid, an unsaturated carboxylic acid having 3 to 8 carbon atoms, specifically, acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, monomethyl maleate, monoethyl maleate and the like are used. . Among these unsaturated carboxylic acids, acrylic acid and methacrylic acid are particularly preferably used.

The above-mentioned ethylene / unsaturated carboxylic acid copolymer may contain a third component in addition to ethylene and the above-mentioned unsaturated carboxylic acid, and the third component may be ethyl acrylate. And unsaturated carboxylic esters such as i-butyl acrylate, n-butyl acrylate and methyl methacrylate, and vinyl esters such as vinyl acetate. However, oil resistance tends to decrease as the amount of the third component increases. Therefore, it is preferable that the third component is not contained, or even if it is contained, the amount is small.

The unsaturated carboxylic acid content of these ethylene-unsaturated carboxylic acid copolymers is 6 to 15 mol%, preferably 7 to 12 mol%. If the unsaturated carboxylic acid content is less than 6 mol%, the compatibility with the polyamide is poor, the transparency is impaired, and remarkable improvement in heat resistance is not achieved. The ethylene content of the ethylene / unsaturated carboxylic acid copolymer is therefore 85 to 94 mol%, preferably 88 to 93 mol%, but when the third component is contained as described above, 5 mol% The ethylene content may be less than the above range accordingly.

The ethylene ionomer resin used in the present invention is such that the ethylene-unsaturated carboxylic acid copolymer is at least partially neutralized by a transition metal and has a degree of neutralization of at least part. 20% or more,
Preferably it is 40 to 100%. When a material having a degree of neutralization of less than 20% by a transition metal is used, or when a material neutralized only with an alkali metal such as lithium, sodium, or potassium or an alkaline earth metal such as calcium or magnesium is used. However, when the polyamide is blended in a considerable amount, transparency is impaired and remarkable improvement in heat resistance is not achieved. Although the reason for this is not necessarily clear, it is considered that the coordination bonding property of the carboxylic acid transition metal salt in the ionomer resin greatly contributes to the interaction with the polyamide resin. Here, examples of the transition metal include manganese, cobalt, nickel, copper, zinc, lead and the like, and zinc is most preferable. Two or more of these transition metals may be used.

As the ionomer resin, 190 ° C., 2
The melt flow rate measured at 160 g load is 0.00
It is preferable to use one having a density of 1 to 100 dg / min, particularly about 0.01 to 10 dg / min.

In the present invention, a polyamide is blended to improve the hot water whitening resistance of the ionomer resin.
These may be resin-like or oligomer-grade molding grades, but have a melting point of 170 ° C. or more,
It is preferable to use a crystalline polyamide having a temperature of 00 ° C. or higher.
Examples of such polyamides include oxalic acid, adipic acid, sebacic acid, dodecane diacid, terephthalic acid, isophthalic acid, dicarboxylic acids such as 1,4-cyclohexyldicarboxylic acid, and ethylenediamine, tetramethylenediamine, pentamethylenediamine, Polycondensation with diamines such as hexamethylenediamine, decamethylenediamine, 1,4-cyclohexyldiamine, and m-xylylenediamine; ring-opening polymerization of cyclic lactams such as ε-caprolactam and ω-laurolactam; 6-aminocaprolene Acids, 9-aminononanoic acid, 11-aminoundecanoic acid,
It is obtained by polycondensation of an aminocarboxylic acid such as 12-aminododecanoic acid or a copolymer of the above-mentioned cyclic lactam, dicarboxylic acid and diamine, and is generally nylon 6, nylon 66, nylon 610, nylon 612,
A molding grade commercially available as nylon 11, nylon 12, copolymer nylon, nylon MXD6, nylon 46, or the like is used. Or primary amine or 1
One or both ends blocked with a secondary diamine
Oligomeric-grade polyamides having a lower amino group can also be used. Such oligomer grades have, for example, an average degree of polymerization of 5 to 35, particularly about 10 to 30.

In the present invention, the mixing ratio of the polyamide to the ionomer resin varies depending on the purpose of use, but the former is 60 to 97 parts by weight, preferably 60 to 85 parts by weight, and the latter is 40 to 3 parts by weight, preferably 60 to 85 parts by weight. 40-1
5 parts by weight. In particular, when an oligomer grade polyamide is used, the amount used should be 3
It is preferably 0 parts by weight or less, particularly preferably 20 parts by weight or less (based on a total of 100 parts by weight of the ionomer and the polyamide). If the compounding ratio of the polyamide is less than the above range, the modifying effect aimed at by the present invention is insignificant, and if the compounding ratio is more than the above range, the ionomer's original characteristics, such as heat sealability, extrusion processability, optical characteristics, etc. Is not preferred because it is impaired.

In order to obtain the composition according to the present invention, a temperature higher than the melting point of the ionomer and the polyamide, for example, 170 to 3
Melt kneading may be performed at a temperature of 00 ° C, preferably 200 to 290 ° C. At this time, if the kneading is insufficient, a transparent and sufficiently modified composition cannot be obtained, so that it is necessary to knead well.

As such a melt kneading apparatus, a resin melt mixing or processing apparatus such as a screw extruder, a Banbury mixer or a roll mixer is used, but a screw extruder is particularly preferably used.

Further, such an ionomer composition is
When the ethylene / unsaturated carboxylic acid copolymer is neutralized with a transition metal cation, the polyamide resin may be added, and the carboxyl group ionization reaction and the polyamide resin blend may be simultaneously performed.

The ionomer composition thus obtained has a melt flow rate at 190 ° C. and a load of 2160 g of 0.01 to 100 dg / min, especially 0, in consideration of moldability, mechanical strength at high temperature, and the like. .02
A range of 範 囲 30 dg / min is preferred.

The ionomer composition according to the present invention may optionally contain additives such as an antioxidant, an ultraviolet absorber, a coloring agent, a stabilizer, a lubricant, and an adhesive, if necessary.

The processed meat packaging film of the present invention may be a monolayer film of the above-mentioned ionomer composition. However, as long as the composition is formed on the side in contact with the processed meat, the film is laminated with another material. In the form of a laminated film. Examples of such other materials include ethylene / vinyl alcohol copolymer, polyamide, polyvinylidene chloride, and polyolefin, and one or more of these layers are laminated on the ionomer layer directly or via an adhesive layer. I have.

The processed meat packaging film of the present invention is particularly suitable for vacuum close packaging. When performing vacuum contact packaging,
The film may be subjected to biaxial stretching or deep drawing in advance. In particular, a biaxially stretched product is used for the purpose of further improving the adhesion by utilizing shrinkage during heat sterilization.

The thickness of the packaging film of the present invention varies depending on the application, but is usually 10 to 100 μm. In the case of a laminated film, the ionomer composition layer has a thickness of 5 to 80 μm.
m and other layers preferably have a thickness of about 20 to 95 μm.

The packaging film of the present invention includes hams such as boneless ham, loin ham, ham with bone, pressed ham, chopped ham, bacon, fresh sausage, liver sausage, smoked sausage, wiener sausage, frankfurter sausage, salami sausage, It can be used for packaging sausages such as fish sausage, meat chunks of various processed meats such as baked pork, sliced products and the like.

[0024]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. First, a method for producing the film of the present invention, a method for evaluating physical properties, and the like will be described below.

(1) Ionomer / polyamide composition
Preparation of Film The ionomer resin and the polyamide resin are mixed and supplied at a predetermined composition ratio by a twin screw extruder (screw diameter: 30 mm, L / D = 32), and the resin temperature is set to 240.
The mixture was kneaded under the conditions of a temperature of 10 ° C. and an extrusion speed of 10 kg / hr to obtain an extruded pellet, which was formed into a film having a thickness of 50 μm and a width of 220 mm using an inflation molding machine. The physical properties of the monolayer film thus obtained were evaluated for the following items.

(2) Hot water resistance test 30 × 30 of ionomer / polyamide composition film
100mm boiling water 400m
After immersion in the film for 30 minutes, the film was observed for whitening. The observation results were visually evaluated in the following three stages. Hot water whitening A: no whitening B: slight whitening C: complete whitening

(3) Animal Oil Resistance The above film is cut into a size of 10 cm × 10 cm, and pork lard, which has been heated and dissolved in advance, is uniformly applied to the surface of the film using a brush. The film thus treated is placed in a metal hermetic container filled with 300 mL of water at the bottom and covered with a metal net for holding a sample, and the container is placed in a heating oven at 100 ° C. Leave for 10 minutes. The degree of roughness of the lard-treated film surface after standing for 10 minutes was observed. The observation results were visually evaluated in the following three stages. Animal oil resistance A: No skin roughness B: Slight skin roughening C: Significant skin roughening

(4) The heat-sealing film is heat-sealed according to the following method and conditions, and the heat-sealed laminated body is 15 mm wide and 15 mm long.
Ten test pieces of cm were prepared. Sealing machine: Single-sided heating type bar sealer (Toyo Seiki) Sealing bar: 10 × 300 mm Sealing pressure: 2 kg / cm ³ (actual pressure) Sealing temperature: 120 to 180 ° C. (every 20 ° C.) Sealing time: 2 seconds Sealing temperature: 120 ~ 180 ℃ (every 20 ℃)

The peel strength of the heat-sealed laminate test piece was measured by a tensile tester to evaluate the adhesiveness. (Here, the take-up direction at the time of film processing is the vertical direction) The measurement conditions are as follows. Measuring machine: Tensile tester Specimen width: 15 mm Peeling speed: 300 mm / min Peeling angle: 90 ° (T-type peeling) Measurement atmosphere: 23 ° C. 50% · Rh

(5) Oxygen gas permeability Measured based on ASTM D1434-M method.

(6) Film optical transformer; ratio of transmitted light to total incident light to film (%) Measurement standard: ASTM D-1746 gloss; standard plate of reflected light amount for light beam with an incident angle of 20 ° on the film surface ASTM D-523 Haze; Percentage of scattered light relative to total transmitted light to the film (%) Measurement standard; ASTM D-1003

(7) Evaluation of Film Biaxial Stretching Processability The processability of each composition film was evaluated under the following conditions. Film to be stretched: Single-layer blown film with a thickness of 250 μm Processing machine: Biaxial stretching machine made by Toyo Seiki Stretching ratio: 3 times longitudinal, 3 times transverse (simultaneous stretching) Stretching speed: 1 m / min Stretching temperature: 80, 90, 130 ° C. The results of biaxial stretching performed by the above method were evaluated in the following two stages. A: The film can be stretched without being cut or perforated during stretching. B: The film can be cut or perforated during stretching.
Stretching impossible

Example 1, Comparative Examples 1-2 Various ionomers shown in Table 1 and various polyamides shown in Table 2 were blended at the respective composition ratios shown in Table 3, and an ionomer / polyamide composition film was obtained by the method (1). Was prepared and evaluated for its hot water whitening ability and oxygen permeability. The results are shown in Table 3. The ionomer composition film of the present invention did not show any hot water whitening and showed good hot water resistance. The oxygen permeability is also about 50% of the oxygen permeability of the ionomer film, and the oxygen barrier property is also good.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

Examples 2 to 5 and Comparative Examples 3 to 5 The ionomer and polyamide were blended at the respective composition ratios shown in Table 4, and the heat-sealing properties and oil resistance of the ionomer / polyamide composition film prepared by the method (1) above. The properties were measured. The results are shown in Table 4. An ionomer composition film having a compounding ratio of ionomer / polyamide within the range specified in the present invention has excellent oil resistance, heat sealing property is equal to or better than that of the ionomer alone film, and film transparency is also good. It is.

[0038]

[Table 4]

EXAMPLE 6 Two stretched films (27 × 27 cm) having a thickness of about 28 μm, prepared from the compositions of Example 1 and Comparative Examples 1 and 2 according to the methods (1) and (7), The three sides are clipped. The bag was filled with about 100 g of commercially available pork sausage, and after sufficient degassing, the remaining one side was clipped. This pork sausage filling bag was immersed in hot water at 90 ° C. for 1 hour to perform shrink packaging. The sausage packaging bag packaged by this method was cooled at room temperature, opened by hand, and the state of peeling of the sausage from the film at that time was observed. The results are also shown in Table 3.
In addition, the measurement result of the meat adhesion was evaluated in three steps as follows. A: When peeling the packaging film from the filling meat, there is a strong resistance. B: When peeling the packaging film from the filling meat, the feeling of resistance is weaker than that of A and can be easily peeled. C: When the packaging film is peeled off from the filling meat, there is no resistance, and in some places, the floating caused by the peeling of the packaging film from the filling meat is seen.

As is evident from the results of the above examples, the packaging film of the present invention is excellent in hot water whitening resistance, oil resistance and meat adhesion, and retains the transparency and heat sealability of the ionomer. Therefore, even if high-temperature sterilization is performed with hot water while the content is being filled as a processed meat packaging film, there is little possibility that a phenomenon such as whitening will occur, and this is suitable for a processed meat packaging film.

[0041]

According to the present invention, there is provided an ionomer composition film having significantly improved heat whitening resistance, and excellent in meat adhesion, oil resistance, heat sealability, transparency, gas barrier properties and high safety to food. The resulting film is less likely to whiten even when subjected to high-temperature sterilization, so that a film useful for packaging processed meat is provided.

Claims (1)

(57) [Claims] (1) an α, β-unsaturated carboxylic acid content of 6-1.
5 mol% of the ethylene / unsaturated carboxylic acid copolymer is neutralized by a transition metal cation, and the degree of neutralization is 20 to 10
A processed meat packaging film comprising an ionomer composition comprising 60 to 97 parts by weight of an ethylene ionomer resin (0%) and 40 to 3 parts by weight of a polyamide.