JP2007238910A - Vinylidene chloride-based copolymer film and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vinylidene chloride-based copolymer film good in mutual slipperiness at high temperatures and slight in deformation of a product. <P>SOLUTION: The vinylidene chloride-based copolymer film is composed of 10-50 wt.% of (A) a vinylidene chloride-based copolymer with 90-96 wt.% in vinylidene chloride content and 120,000-130,000 in weight-average molecular weight and 50-90 wt.% of (B) a second vinylidene chloride-based copolymer 80 wt.% or greater but less than 90 wt.% in vinylidene chloride content and 120,000-130,000 in weight-average molecular weight. A method for producing the vinylidene chloride-based copolymer film is also provided, comprising making orientation of the unoriented vinylidene chloride-based copolymer film at temperatures within a specific range. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film suitable for packaging in which boil-retort processing is performed after packaging, such as fish meat / livestock sausage and ham. Specifically, the present invention relates to an excellent vinylidene chloride copolymer film having good slipperiness between films at a high temperature (60 ° C. to 120 ° C.) and little product deformation in boil and retort treatment.

Since vinylidene chloride copolymer films have excellent properties such as water vapor and oxygen barrier properties and heat resistance, they are used for food packaging materials for boil and retort of sausages, ham, and other foods. In addition, it is also widely used for packaging materials such as fish meat, livestock sausage, and ham that are filled and packaged by an automatic filling and packaging machine (for example, “ADP (registered trademark)” manufactured by Asahi Kasei Life & Living Co., Ltd.).
(1) When using an automatic filling and packaging machine to place thousands of filled and packaged fish / meat sausages and ham randomly in a container and sterilize with hot water at 90 ° C or 120 ° C Due to the poor slipperiness of the film, the sausages that are overlapped are heat-treated while bent and deformed, resulting in loss of commercial value. (2) The heat shrinkage rate is too high or the heat shrinkage stress is too strong and deformed. There is a problem that the amount of waste disposal increases and the yield deteriorates. (3) Furthermore, with the recent increase in productivity, the product sausage is taken out of the retort kettle after shortening the cooling time after the retort treatment, so the surface temperature of the product sausage immediately after taking out becomes 60 ° C to 80 ° C. Since the slipperiness is poor, the overlapping product sausages are blocked (lightly bonded), making it difficult to take out, and workability may be reduced or scratched.

The flow of production of sausage, ham, etc. is generally filling → boil (90 ° C.) or hot water sterilization with retort (120 ° C.) → conveying → pinhole detection → packaging. Powder of silicon dioxide, calcium carbonate, etc. for the purpose of preventing unevenness on the film surface and preventing self-adhesion to improve the slipperiness between the film and the machine during filling, and the slipperiness during transport of sausages and ham packaging In some cases, a fibrous inorganic substance is added, or an organic lubricant such as a fatty acid amide or a surfactant is added and deposited on the film surface to impart slipperiness.
However, if a powdery inorganic substance is added too much in order to give further slipperiness, the film is whitened and the commercial value is lowered. In addition, excessive addition of an organic lubricant causes excessive deposition on the film surface, resulting in poor sealing properties, and excessive precipitation of the lubricant on the film surface during hot water sterilization treatment comes into contact with water and causes stickiness. Will occur. The addition of these additives alone does not improve slipperiness at high temperatures during boil / retort treatment or immediately after heat treatment, and does not reduce deformation of the product sausage.

A film comprising a vinylidene chloride copolymer resin composition in which two or more kinds of different reduced viscosity vinylidene copolymers are mixed at a specific ratio (for example, Patent Document 1), or at least two types of reduced viscosity vinylidene chloride copolymer It is composed of a mixed vinylidene chloride resin composed of a polymer, an ethylene and vinyl acetate copolymer, a copolymer of ethylene and acrylic acid, methacrylic acid or an alkyl ester thereof, and at least one copolymer selected from MBS resins. A film made of a vinylidene chloride copolymer-containing resin composition (for example, Patent Document 2) is disclosed, but the product is improved by slipperiness at high temperatures (60 ° C. to 120 ° C.) during boil / retort treatment or immediately after heat treatment. We are not satisfied with the reduction in deformation.
JP-A-11-71492 International Publication No. 96/034050 Pamphlet

  The present invention provides a vinylidene chloride copolymer film having excellent performance with little product deformation even after retort and boil treatment because the slipperiness between films at high temperatures (60 ° C. to 120 ° C.) is good. With the goal.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the problems can be solved by the present invention.
That is, the present invention is as follows.
(1) 10 to 50% by weight of vinylidene chloride copolymer (A) having a vinylidene chloride content of 90 to 96% by weight and a weight average molecular weight of 1 to 130,000, and a vinylidene chloride content of 80 A vinylidene chloride copolymer film comprising 50% to 90% by weight of a vinylidene chloride copolymer (B) having a weight average molecular weight of 1 to 130,000 and not less than 90% by weight.
(2) 10 to 50% by weight of vinylidene chloride copolymer (A) having a vinylidene chloride content of 90 to 96% by weight and a weight average molecular weight of 1 to 130,000, and a vinylidene chloride content of 80 Inflation method of mixed vinylidene chloride copolymer resin composition comprising 50% to 90% by weight of vinylidene chloride copolymer (B) having a weight average molecular weight of 1 to 130,000 and not less than 90% by weight A method for producing a vinylidene chloride copolymer film, comprising: melt extrusion and forming a tubular extrudate, followed by stretching at a stretching temperature of 25 to 35 ° C.

  Since the vinylidene chloride copolymer film of the present invention has good slipperiness between films at high temperatures (60 ° C. to 120 ° C.), there is little product deformation after retort / boil treatment.

The present invention will be described in detail below.
The vinylidene chloride copolymer film of the present invention is a vinylidene chloride copolymer (A) having a vinylidene chloride content of 90% by weight to 96% by weight and a weight average molecular weight of 1 to 130,000. And a vinylidene chloride copolymer (B) having a vinylidene chloride content of 80 wt% or more and less than 90 wt% and a weight average molecular weight of 1 to 130,000 is 50 to 90 wt%. .
The vinylidene chloride copolymer (A) of the present invention contains 90% to 96% by weight of vinylidene chloride, and contains 80% by weight or more and less than 90% by weight of vinylidene chloride ( Compared with B), the content of vinylidene chloride is large. Therefore, a difference in crystallinity occurs between the vinylidene chloride copolymers (A) and (B) during stretching. Due to this difference in crystallinity, fine irregularities are formed on the film surface, and the film has good slipperiness even at high temperatures (60 ° C. to 120 ° C.).

  When a powdery inorganic material such as silicon dioxide or calcium carbonate is added as a satin finish in order to impart the slipperiness of the film, the portions where the satin finish exists are uneven, and the nonexistent portions become flat. Since the slipperiness becomes better as there are more uneven parts, it has been necessary to increase the addition amount of satin preparation to eliminate the flat part, but the problem is that if the addition amount is increased, the film will whiten was there. However, in the film of the present invention, minute unevenness is formed on the entire film surface due to the difference in crystallinity. Therefore, the combination of the addition of a small amount of satin finish and the minute unevenness on the entire surface can exhibit good slipperiness at high temperature without inhibiting transparency. Small irregularities on the surface exist even after the boil and retort treatment, the slipperiness at high temperature becomes good, and the overlapped products are separated and heat-treated, so that the product deformation is reduced.

  For the formation of minute irregularities on the film surface to improve the slipperiness at high temperature, a specific vinylidene chloride copolymer (A) and a specific vinylidene chloride copolymer (B) are used at a specific ratio. It is necessary to mix. The vinylidene chloride content of the vinylidene chloride copolymer (A) needs to be 90% by weight or more and 96% by weight or less, and preferably 91 to 95% by weight. The mixing ratio of (A) in the vinylidene chloride copolymer film is 10 to 50% by weight, preferably 15 to 45% by weight. When the vinylidene chloride copolymer (A) is in the range of 10 to 50% by weight, there is no excessive difference in crystallinity with the vinylidene chloride copolymer (B) during stretching. Occurrence is suppressed, and bleedout of the liquid additive described later due to excessive crystallization during film storage is also small. Furthermore, there is little thermal degradation (decomposition) of the resin and outflow of thermal decomposition products (eye and eyes) from the die during continuous molding.

In order to provide a difference in crystallinity with the vinylidene chloride copolymer (A) at the time of stretching, the vinylidene chloride content of the vinylidene chloride copolymer (B) may be 80% by weight or more and less than 90% by weight. Necessary, preferably 82 to 88% by weight. The vinylidene chloride content of the vinylidene chloride copolymer (B) is smaller than that of the vinylidene chloride copolymer (A), and the mixing ratio is 50 to 90% by weight. It is.
In order to suppress bleed of the liquid additive described later during film storage, the bleed suppression effect is higher as the amorphous part increases. Therefore, a composition containing 50 to 90% by weight of the total vinylidene chloride copolymer (B) having a relatively small amount of crystal components and a vinylidene chloride content of 80% by weight or more and less than 90% by weight is effective for suppressing bleeding. Also effective. These effects are not controlled only by the vinylidene chloride content in the vinylidene chloride copolymer film of the present invention, but are formed when the vinylidene chloride copolymer is stretched, the size of crystals, etc. Is also considered to be involved.

In addition, slipperiness and film strength deterioration due to low molecular weight substances contained in the vinylidene chloride copolymer, whitening of the film during stretching due to high molecular weight substances, generation of cracks, thermal deterioration (decomposition) of the resin, From the viewpoint of preventing the outflow of the pyrolyzate (eye), the vinylidene chloride copolymers (A) and (B) have a weight average molecular weight of 1 to 130,000. Further, since the vinylidene chloride copolymers (A) and (B) both have a weight average molecular weight in the range of 1 to 130,000, the uniformity increases during melt-kneading, and minute irregularities on the film surface are formed uniformly. In addition, the slipperiness between films is improved.
The vinylidene chloride copolymer (A) and the vinylidene chloride copolymer (B) used in the present invention are composed mainly of vinylidene chloride, and examples of monomers that can be copolymerized with vinylidene chloride include, for example, vinyl chloride, Examples thereof include acrylic acid esters such as methyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, and methacrylic acid esters such as methyl methacrylate and butyl methacrylate. Two or more kinds may be mixed. Among these, vinyl chloride, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate are preferable.

Vinylidene chloride copolymers include liquid plasticizers such as dibutyl sebacate, acetyl tributyl citrate, glycerin diacetomonolaurate, epoxidized soybean oil, epoxidized linseed oil, bisphenol A diglycidyl ether, epoxidized octyl stearate It is preferable to mix 1 to 10% by weight of a liquid additive such as a heat stabilizer typified by an epoxy compound such as epoxidized palm oil.
If necessary, organic or inorganic pigments, spherical or amorphous silicon dioxide, calcium carbonate, magnesium oxide, and other satin finishes, fatty acid amides and other lubricants in a total amount of 0.01 to 1.0. About 0.1% by weight of surfactants such as sorbitan fatty acid ester, polyglycerin fatty acid ester and polyoxyethylene fatty acid ester may be added depending on the application, and fluorine processing as a processing aid. An auxiliary agent may be added in an amount of 0.01 to 1.0% by weight. These additives may be added before or after the polymerization of the vinylidene chloride copolymer.

The method of mixing the additive, pigment and other additives into the vinylidene chloride copolymer (A) and (B) is not particularly limited, and a known method is applied, for example, a high speed Henschel mixer, a ribbon blender, etc. The heating / cooling mixing method is applied.
The vinylidene chloride copolymer film according to the present invention is produced by an inflation method. When the film of the present invention is prepared by the inflation method, 1) a composition comprising the two types of vinylidene chloride copolymers (A) and (B) of the present invention is extruded from a circular die of a screw extruder, and 2) a tubular shape. Polyethylene glycol or the like is sealed inside the extrudate (hereinafter referred to as “Parison”), folded with pinch roll while cooling with cold water of about 10 ° C., 3) let water pass through 20 to 45 ° C., and water is drained with pinch roll. 4) Enclose air in a parison folded at room temperature 25-35 ° C. so that it becomes a cylinder of 2 to 3 m in length. 5) Further inflate with air and inflate, in the longitudinal (MD) direction. 2.5 to 3.5 times, and biaxially stretched 3.5 to 4.5 times in the width (TD) direction, and the tubular film is folded with a pinch roll. How to it is preferred.

During boil and retort processing of packaged sausage, ham, etc. filled and packaged, prevents damage due to excessive thermal shrinkage stress in the TD direction, prevents deformation, and causes whitening of the film due to excessive crystallization, and double ply film The stretching temperature is preferably in the range of 25 ° C to 35 ° C from the viewpoint of preventing a decrease in peel strength between the films. The stretching temperature is the surface temperature of the parison immediately before the inflation of 5).
The vinylidene chloride copolymer film of the present invention preferably has a shrinkage of 25 to 40% in both the MD and TD directions at 120 ° C., and the heat shrinkage stress is 1.0 to 2 in both the MD and TD directions at 120 ° C. It is preferable to have 0.0 MPa (shrinkage is 120 ° C., ASTM D-2732, heat shrinkage stress is 120 ° C., measured by ASTM D-1504). The reason for setting to 120 ° C. is that the retort treatment temperature is generally around 120 ° C. By providing an appropriate shrinkage rate and heat shrinkage stress, the film is appropriately shrunk by heat treatment, and ham, sausage and the like are free from wrinkles and deformation, and have an appropriate tension, resulting in a good product finish.

When filling and packaging with an automatic filling and packaging machine for filling ham, sausage, etc. (for example, automatic filling and packaging machine ADP (registered trademark) manufactured by Asahi Kasei Life & Living Co., Ltd.), etc. After the bag is made, the part where the film overlaps (hereinafter referred to as overlap) is sealed with high frequency, and when the film is fed with the feed roller, it prevents the film from expanding and contracting between the folder and the feed roller. For excellent bag, seal, and product dimension (length) stability, the 2% elastic modulus (measured at 23 ° C. and ASTM D-882) is preferably 200 to 400 MPa in both MD and TD directions, and the coefficient of dynamic friction (23 ° C., (Measured by ASTM D-1894) is preferably 0.1 to 0.3 for film-film and 0.05 to 0.25 for film-mirror metal. There.
Furthermore, in order to stabilize the film properties such as 2% elastic modulus, dynamic friction coefficient, heat shrinkage rate, heat shrinkage stress, etc., a flat and long shaped film should be aged for 7 days or more before and after the slit at 25 to 35 ° C. Is preferred.
For the molded film, heat treatment such as corona discharge treatment, roller type, end fixing type, hot air blowing type, etc. should be performed at the time of inflation, after inflation, folded with a pinch roll, or at the time of post processing. You can also.

The present invention will be specifically described based on the following examples.
The measurement methods used in the present invention are summarized below.
(1) Vinylidene chloride content of vinylidene chloride copolymer Measured using a high-resolution proton nuclear magnetic resonance measuring apparatus (H-NMR: α-400 <trade name> manufactured by JEOL Ltd.). A solution obtained by dissolving 5% of a sample in deuterated tetrahydrofuran is measured by 400 MHz H-NMR under a measurement temperature of about 27 ° C. The vinylidene chloride content is calculated using a specific chemical shift based on tetramethylsilane in the spectrum.
For example, when the copolymer resin with vinylidene chloride resin is vinyl chloride, it is derived from the solvent from the peak between 3.50 to 4.20 ppm, 2.80 to 3.50 ppm, and 2.00 to 2.80 ppm. The integral values obtained by subtracting the peaks were obtained as the following formulas as (A), (B), and (c), respectively.
VDC content (% by weight) = {97.0 × ((A) + (B) / 2) × 100} / {97.0 × ((A) + (B) / 2) + 62.5 × (( c) + (B) / 2)}
(2) Measurement of weight average molecular weight of vinylidene chloride copolymer The gel permeation chromatograph (GPC) method was used. More specifically, 0.05% of a vinylidene chloride copolymer is dissolved in tetrahydrofuran, and measurement is performed using monodispersed polystyrene having a known molecular weight as a standard substance. As a measuring device, Tosoh Co., Ltd. 8000 series <trade name> was used.

(3) Packaging suitability An automatic filling and packaging machine (ADP (registered trademark), manufactured by Asahi Kasei Life & Living Co., Ltd.) forms a film with a film width of 90 mm into a cylindrical shape, and sets the overlap portion to 10 mm. The seal electrode is sealed at a high frequency while touching the film so that the seal line width is 1.0 to 1.5 mm at the center of the wrap, formed into a cylindrical shape, and filled with surimi for fish inside the cylindrical film, Both ends are clipped with an aluminum steel wire, and a package is prepared by setting the length between the clips to 195 mm under a filling condition of 240 wires / min.
The number of discharges (sparks) caused by foreign matters during high-frequency sealing during the production of 20,000 packages is evaluated as follows.
○: 0 times Δ: 1 time ×: 2 times or more For the overlap width variation, 200 packages are evaluated in the following manner.
○: Less than 10 mm ± 1 mm Δ: Less than 10 mm ± 2 mm ×: 10 mm ± 2 mm or more Evaluation of 200 packages in the following manner with respect to variations in the length of the package (between clips).
○: The maximum and minimum lengths are less than 195 ± 2 mm △: The maximum and minimum lengths are less than 195 ± 4 mm ×: The maximum and minimum lengths are 195 ± 4 mm or more

(4) High temperature sliding property 200 packages prepared in the same manner as (3) packaging suitability are placed in a container whose side part can be opened and closed, arranged in a row of 20 x 10 stages, and the whole container is retorted at 120 ° C for 20 minutes. After processing, after cooling with water and adjusting the surface temperature of the 10th stage package to 60 ° C to 65 ° C, the side of the container is opened and placed on the desk, and the bottom of the container and the desk surface Inclination is performed until the angle becomes 45 ° and how the package is dropped from the container is evaluated in the following manner.
◯: 150 to 200 falls Δ: 100 to 149 falls ×: 0 to 99 falls Also, the appearance of the package is visually observed.

(5) Deformation In a container whose upper surface can be opened and closed, 200 packages prepared in the same manner as in the above (3) packaging suitability are randomly placed, the whole container is retorted at 120 ° C. for 20 minutes, and then cooled with water to remove the container. Take out and arrange the package on a graph paper line, measure the number of the package having a gap of 5 mm or more between the both ends and the center, and perform the evaluation in the following manner.
○: Within 20 △: Within 21-50 ×: 51 or more

[Example 1]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 125,000) 49% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) 3 parts by weight of dibutyl sebacate as a plasticizer and acetyltributyl citrate per 100 parts by weight of a mixture of 51% by weight (content / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 125,000) 2.5 parts by weight, 2 parts by weight of epoxidized soybean oil as a heat stabilizer, 0.1 parts by weight of amorphous silicon dioxide having an average particle size of 5μ as a satin finish, 0.1 parts by weight of stearamide as a lubricant, As a pigment, 0.2 parts by weight of Pigment Yellow 139 (manufactured by Clariant Japan Co., Ltd., product name GraPhtol Yellow H2R), P gment RED166 (manufactured by Ciba Specialty Chemicals Co., Ltd. trade name CROMOPHTAL Scarlet RN) and 0.1 parts by weight, was added and mixed.
The obtained mixture was extruded into a tube with a melt extruder, supercooled in a cold water bath at about 10 ° C., passed through 35 ° C. water, stretched at 30 ° C., 3.0 times in the longitudinal (MD) direction, and the width (TD A tubular film obtained by biaxial stretching of 4.0 times in the direction) was folded with a pinch roll to produce a flat long double-ply film original fabric having a width of about 1 m and a target thickness of 40 μm.
The original fabric was aged at 30 ° C. for 7 days, then cut into a width of 90 mm while being unwound and wound up to prepare a film product, which was further aged at 30 ° C. for 7 days. A package was prepared from this film product in the same manner as the above (3) packaging suitability, and the packaging suitability, high-temperature slippage of the package, deformation, and appearance of the package after retorting were evaluated.

[Example 2]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 1330,000) 20% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 88% by weight / 12% by weight, weight average molecular weight 12,000,000) The additive was added and mixed in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight. Then, a film product and a package were prepared and evaluated in the same manner as in Example 1.

[Example 3]
15% by weight of vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 95% by weight / 5% by weight, weight average molecular weight 12,000,000), vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 86% by weight / 14% by weight, weight average molecular weight 125,000) The additive was added and mixed in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight. Then, a film product and a package were prepared and evaluated in the same manner as in Example 1.

[Example 4]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 12,000,000) 45% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 82% by weight / 18% by weight, weight average molecular weight 133,000) Additive mixing in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight of a mixture of 55% by weight. Then, a film product and a package were prepared and evaluated in the same manner as in Example 1.

[Example 5]
In the vinylidene chloride copolymer mixture of Example 1, 0.5 part by weight of sorbitan monostearate as a surfactant and 0.05 part by weight of a fluorine processing aid (Viton Free Flow manufactured by DuPont Dow Elastomer Co., Ltd.) Except for the addition, additives were added and mixed in the same manner as in Example 1 to produce a film product and a package and evaluated in the same manner as in Example 1.

[Example 6]
Pigment Yellow191: 1 (trade name CROMOPHTAL Yellow HRPA manufactured by Ciba Specialty Chemicals Co., Ltd.), 0.2 parts by weight, Pigment Violet 19 (Ciba Specialty Chemicals) was added to the vinylidene chloride copolymer mixture of Example 1. Additives were added in the same manner as in Example 1 except that the product name CROMOPHTAL Red2020) was changed to 0.1 parts by weight, and the satin finish was changed to 0.1 parts by weight of spherical silicon dioxide having an average particle size of 5 μm. After mixing, a film product and a package were prepared and evaluated in the same manner as in Example 1.

[Example 7]
A film product and a package were prepared in the same manner as in Example 1 except that the stretching temperature was changed to 26 ° C., and evaluated in the same manner as in Example 1.

[Example 8]
A film product and a package were prepared in the same manner as in Example 1 except that the stretching temperature was 34 ° C., and evaluated in the same manner as in Example 1.

[Comparative Example 1]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 125,000) 60% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 125,000) The additive was added and mixed in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight. In the same manner as in Example 1, a film product and a package were prepared and evaluated in the same manner as in Example 1.

[Comparative Example 2]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 125,000) 5% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Additives were added in the same manner as in Example 1 except that the content was changed to 100 parts by weight of a mixture of 95% by weight / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 125,000). After mixing, a film product and a package were prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1.

[Comparative Example 3]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 11 million) 30% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Additives were added in the same manner as in Example 1 except that the content was changed to 100 parts by weight of a mixture of 70% by weight (content / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 125,000). After mixing, a film product and a package were prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1.

[Comparative Example 4]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91% by weight / 9% by weight, weight average molecular weight 125,000) 30% by weight, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Additives were added in the same manner as in Example 1 except that the content was changed to 100 parts by weight of a mixture of 70% by weight (content / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 14 million). After mixing, a film product and a package were prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1.

[Comparative Example 5]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 89 wt% / 11 wt%, weight average molecular weight 12,000,000) 20 wt%, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 86 wt% / 14 wt%, weight average molecular weight 120,000) Additive mixing in the same manner as in Example 1 except that the mixture was changed to 100 wt parts. Then, a film product and a package were prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1.

[Comparative Example 6]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 95 wt% / 5 wt%, weight average molecular weight 125,000) 30 wt%, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 76% by weight / 24% by weight, weight average molecular weight 125,000) The additive was added and mixed in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight. Then, a film product and a package were prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1.

[Comparative Example 7]
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 97 wt% / 3 wt%, weight average molecular weight 12,000,000) 40 wt%, vinylidene chloride-vinyl chloride copolymer (vinylidene chloride) Content / vinyl chloride content = 89% by weight / 11% by weight, weight average molecular weight 125,000) The additive was added and mixed in the same manner as in Example 1 except that the mixture was changed to 100 parts by weight. Then, a film product and a package were prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1.

[Comparative Example 8]
Example 1 except that only vinylidene chloride-vinyl chloride copolymer (vinylidene chloride content / vinyl chloride content = 91 wt% / 9 wt%, weight average molecular weight 125,000) was changed to 100 parts by weight. Additives were added and mixed in the same manner as in Example 1, film products and packaging bodies were prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1.
Table 1 shows the vinylidene chloride copolymer resin compositions used in Examples 1-8 and Comparative Examples 1-8. Table 2 shows the evaluation results of Examples 1 to 8 and Comparative Examples 1 to 8. As is clear from the evaluation results shown in Table 2, the vinylidene chloride copolymer film in the claims of the present invention is generally satisfactory in terms of high-temperature slipperiness, deformation of the package, and the like.

  The vinylidene chloride copolymer film of the present invention can be used as a packaging material for excellent fish meat, livestock meat sausage, ham, etc., which has good slipperiness between films at high temperatures and little product deformation.

Claims (2)

  10 to 50% by weight of vinylidene chloride copolymer (A) having a vinylidene chloride content of 90% to 96% by weight and a weight average molecular weight of 1 to 130,000, and a vinylidene chloride content of 80% or more A vinylidene chloride copolymer film comprising less than 90% by weight and 50 to 90% by weight of a vinylidene chloride copolymer (B) having a weight average molecular weight of 1 to 130,000.   10 to 50% by weight of vinylidene chloride copolymer (A) having a vinylidene chloride content of 90% to 96% by weight and a weight average molecular weight of 1 to 130,000, and a vinylidene chloride content of 80% or more A mixed vinylidene chloride copolymer resin composition comprising less than 90% by weight and 50 to 90% by weight of a vinylidene chloride copolymer (B) having a weight average molecular weight of 1 to 130,000 is melt extruded by an inflation method. A method for producing a vinylidene chloride copolymer film, comprising producing a tubular extrudate and then stretching at a stretching temperature of 25 to 35 ° C.