JP3523340B2 - Vinylidene chloride polymer moldings - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinylidene chloride polymer (hereinafter abbreviated as "PVDC") molded article,
More specifically, the present invention relates to a molded product such as a film or a sheet, which is excellent in discoloration and discoloration prevention properties, thermal stability and heat resistance. The PVDC molded product of the present invention is particularly suitable for food packaging.

[0002]

2. Description of the Related Art PVDC is a resin having a characteristic of oxygen gas barrier property, and by utilizing this characteristic, PVDC alone or other thermoplastic resin has been conventionally used as a packaging material for ham, sausage or various meats. Formed products such as films and sheets in which the above are laminated are widely used.

Most of such films and sheets are used by making bags, and usually they are formed into a bag shape or a tubular shape, and then sealed by a method such as heat or high frequency to make a bag. I am trying. Among the films and sheets that are used in this way, those that require PVDC resistance to heat during sealing (hereinafter abbreviated as “heat resistance”) can be manufactured by using the electronic Irradiating radiation such as rays. For example, when a film or sheet in which polyethylene is laminated as a PVDC layer as a seal layer is irradiated with an electron beam or the like, the PVDC layer is deformed by sealing heat (for example, the PVDC layer in the seal part is partially melted and thinned). To prevent the thickness of the polyethylene layer from becoming non-uniform) and melt cutting of the polyethylene layer (the polyethylene layer is partially melted too much at the seal part and the polyethylene layer is cut due to the decrease in strength during melting). The resulting bag-making product has advantages such as less deterioration in oxygen gas barrier property and impact strength.

However, irradiation with radiation causes PVD
Decomposition of C occurs, which causes a problem that the film or sheet is discolored or colored, and hams, sausages, various meats, etc. are added to the bag-shaped or tubular materials obtained from the film or sheet. When packaging the contents of the product, there are concerns that the contents may be adversely affected, the image of the product may deteriorate, and consumers may be less motivated to purchase.Therefore, prevention of discoloration and coloring is strongly desired. ing.

Up to now, there has been reported a method of blending PVDC with a known heat stabilizer such as a hindered phenol compound, a hindered amine compound, a dialkylthiodicarboxylic acid ester, an antioxidant, etc. It has almost no effect in preventing discoloration or coloring due to radiation irradiation. Further, Japanese Patent Publication No. 5-18343 discloses a resin composition which is excellent in γ-ray resistance by adding a thioalcohol compound to a halogen-containing resin. However, the molded product obtained by this method has a strong odor and is not suitable for packaging foods. The inventors of the present invention disclosed in Japanese Unexamined Patent Publication No. 6-19252.
No. 3 proposes a PVDC composition which is excellent in heat stability and has no food hygiene problems, and based on these findings, research has begun to solve the above problems.

[0006]

As described above, a vinylidene chloride polymer molded product excellent in discoloration and coloration-preventing properties, thermal stability and heat resistance, particularly as a molded product for food packaging, has a problem in food hygiene. There is a strong demand for the development of non-existing films and sheets, and the present invention has been found as a result of continuous research to solve these problems.

[0007]

According to the present invention, the fatty acid has 1 carbon atom per 100 parts by mass of PVDC.
6 to 22 glycerin monofatty acid ester (hereinafter abbreviated as "GME") 0.05 to 2.5 parts by mass, epoxy stabilizer 0.05 to 4 parts by mass and plasticizer 0.1 to 10
P that is composed of a composition containing parts by weight and is irradiated with radiation.
VDC moldings are provided. Also, a group consisting of 0.05 to 2.5 parts by mass of GME, 0.05 to 4 parts by mass of an epoxy-based stabilizer, 0.1 to 10 parts by mass of a plasticizer, 100 parts by mass of PVDC, and sodium citrate and potassium citrate. Provided is a PVDC molded article which is composed of a composition containing 0.01 to 3 parts by mass of at least one alkali metal citrate selected from the group, and which has been irradiated with radiation. Further, there is provided a molded product containing a layer composed of one of the molded products and a layer composed of a thermoplastic resin. further,
A film or sheet is provided as the molded product.

The present invention will be described in detail below. [Vinylidene chloride polymer] PVDC used in the present invention
Is 3 to 30 mass% of a monomer copolymerizable with 70 to 97 mass% of vinylidene chloride, and preferably 80 to 80 mass% of vinylidene chloride.
It is a polymer composed of 95% by mass and 5 to 20% by mass of a copolymerizable monomer. If the content of vinylidene chloride is less than 70% by mass, the gas barrier properties of the polymer obtained, such as oxygen and water vapor, are deteriorated. On the other hand, if it exceeds 97% by mass, the melting point becomes too high and thermal decomposition occurs during melt molding. There are difficulties such as becoming easier. Vinylidene chloride content is 80-95% by mass
The range of (2) is preferable because the obtained polymer has a good balance between gas barrier properties against oxygen and water vapor and moldability.

Examples of monomers copolymerizable with vinylidene chloride include vinyl halides such as vinyl chloride; alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, and lauryl acrylate. Ester; Methyl methacrylate, ethyl methacrylate, methacrylic acid alkyl ester such as butyl methacrylate; acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, maleic acid alkyl ester, itaconic acid alkyl ester, Acrylonitrile, vinyl acetate, ethylene,
Examples include propylene, isobutylene and butadiene.

The reduced viscosity is an index showing the molecular weight of the polymer, and when the cyclohexanone is used as a solvent and the concentration is 4 g / liter (g / L) and the reduced viscosity is usually from 0.035 to 0. The range of 080 L / g, preferably the range of 0.038 to 0.065 L / g is desirable. If the reduced viscosity is less than 0.035 L / g, the molding process is difficult because the molecular weight is too low.
If it exceeds 0 L / g, the molecular weight becomes too high and melt molding becomes difficult. Reduced viscosity 0.038-0.065L /
Polymers in the range of g are suitable from the viewpoint of physical properties and processability.

[Glycerin Monofatty Acid Ester] GME used in the present invention has a fatty acid having 16 to 2 carbon atoms.
2 is a glycerin monofatty acid ester. Such GME has been conventionally known as a lubricant for improving the antistatic property of a thermoplastic resin, the fluidity at the time of processing and molding, and the releasability. However, when the present invention is used, The effect of improving the discoloration and coloration-preventing property of the molded article irradiated with radiation is not known, and is the first to be revealed in the present invention. Examples of GME used in the present invention include glycerin monostearate, glycerin monopalmitate, glycerin monooleate, glycerin monobehenate and the like. These may be used alone or in combination. From the effect of improving discoloration and discoloration preventing property of the present invention, glycerin monostearate, glycerin monopalmitate and glycerin monobehenate are preferable, and among them, glycerin monostearate has thermal stability and handleability. It is also suitable from the viewpoint. The GM used in the present invention
When E is less than 30% by mass, the fatty acid has 16 carbon atoms.
It may contain glycerin difatty acid ester or glycerin trifatty acid ester which is -22 .

The blending ratio of GME is 0.05 to 2.5 parts by mass, preferably 0.1 to 100 parts by mass of PVDC.
1.7 parts by mass, particularly preferably 0.3 to 1.5 parts by mass. When the content of GME is less than 0.05 parts by mass,
The discoloration and coloration prevention properties aimed by the present invention are not sufficient,
On the other hand, if the GME content exceeds 2.5 parts by mass, problems such as difficulty in molding and whitening of the obtained molded product occur. The content of GME is preferably in the range of 0.1 to 1.7 parts by mass in view of physical properties such as moldability, discoloration and coloration prevention property, and strength.
In the range of parts by mass, the balance with such workability and physical properties becomes even better.

[Epoxy Stabilizer] The epoxy stabilizer used in the present invention is a compound having an epoxy group in the molecule which is usually used as a heat stabilizer for PVDC. Examples of the epoxy-based stabilizer include epoxidized vegetable oil obtained by epoxidizing linseed oil, soybean oil, coconut oil, safflower oil, sunflower oil, cottonseed oil, sunflower oil, etc .; epoxidized octyl stearate typified by Fatty acid monoesters; epoxidized fatty acid diesters obtained by epoxidizing unsaturated fatty acid glycol esters; alicyclic epoxides typified by epoxy hexahydrophthalic acid ester; Among these, epoxidized vegetable oil is preferable from the viewpoint of heat stability and food hygiene.

The mixing ratio of the epoxy stabilizer is PVDC.
The amount is 0.05 to 4 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 2.5 parts by mass with respect to 100 parts by mass. When the compounding ratio of the epoxy stabilizer is less than 0.05 parts by mass, the heat stabilizing effect is small, and when it exceeds 4 parts by mass, the molded product may be colored or the gas barrier property against oxygen and the like may be deteriorated. There is. A blending ratio of 0.3 to 3 parts by mass provides a good balance of heat stabilizing effect, gas barrier properties, moldability, and the like, and a blending ratio of 0.5 to 2 parts by mass makes this particularly favorable. .

[Plasticizer] The plasticizer used in the present invention is not particularly limited as long as it is a plasticizer used in ordinary PVDC molding. Specific examples of the plasticizer include aliphatic dibasic acid esters such as dioctyl adipate, dioctyl sebacate and dibutyl sebacate; hydroxy polycarboxylic acid esters such as tributyl citrate and acetyl tributyl citrate; and diacetyl monolauryl glycerin Examples of the component include glycerin fatty acid ester plasticizer such as glyceride; polyester plasticizer and the like. The blending ratio of the plasticizer is 0.1 to 10 parts by mass, preferably 0.5 to 9 parts by mass with respect to 100 parts by mass of PVDC. If it is less than 0.1 part by mass, the molding process is difficult, while if it exceeds 10 parts by mass, the oxygen gas barrier property, which is a characteristic of PVDC, may be impaired. 0.
In the range of 5 to 9 parts by mass, the balance between molding processability and physical properties such as oxygen gas barrier property is particularly good.

[Alkali Metal Citric Acid Salt] The alkaline metal citrate salt used in the present invention is at least one selected from the group consisting of sodium citrate and potassium citrate. As sodium citrate, trisodium citrate (crystal) and trisodium citrate (anhydrous)
In particular, trisodium citrate (crystal) is preferable. Moreover, potassium citrate is 1 potassium citrate and 3 potassium citrate, and especially 3 potassium citrate is preferable. These alkali metal citrates are colorless crystals or white powders. Sodium citrate and potassium citrate may be used alone or in combination. Alkali metal citrate is used as a food additive and is preferable in that it has no problem in food hygiene, and moreover, it has an effect of improving thermal stability against PVDC as compared with the case where the metal salt is not used. It is characteristic in that it is improved.

The mixing ratio of the alkali metal citrate is P
It is 0.01 to 3 parts by mass, preferably 0.1 to 2 parts by mass, and more preferably 0.3 to 1 part by mass with respect to 100 parts by mass of VDC. When the blending ratio is less than 0.01, the heat stabilizing effect is small, and when it exceeds 3 parts by mass, the molded product may be colored or the oxygen gas barrier property may be deteriorated. The range of 0.1 to 2 parts by mass provides a good balance in performance, and the range of 0.3 to 1 parts by mass provides a particularly good heat stabilizing effect.

The total amount of the epoxy stabilizer and alkali metal citrate used is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, based on 100 parts by mass of PVDC. With too much total usage,
The molded product may be colored. Further, the ratio of the epoxy stabilizer and the alkali metal citrate to be used is in the range of 5: 5 to 9.5: 0.5 in terms of mass ratio, which is particularly advantageous from the viewpoint of improving thermal stability. Is.

[Composition] One composition of the present invention is PV
GME 0.05 to 2.5 parts by mass, epoxy stabilizer 0.05 to 4 parts by mass and plasticizer 0.1 to 10 parts by mass per 100 parts by mass of DC, and another composition GME is 100 parts by mass of PVDC.
0.05 to 2.5 parts by mass, epoxy stabilizer 0.05 to
4 parts by mass, 0.1 to 10 parts by mass of a plasticizer, and 0.01 to 3 parts by mass of at least one alkali metal citrate selected from the group consisting of sodium citrate and potassium citrate.

The above-mentioned composition can be prepared by mixing the respective components by an ordinary method, for example, using various mixers such as a blender, a Henschel mixer and a kneader. In addition, each component may be appropriately added and mixed during or after the polymerization of PVDC. When the alkali metal citrate is used, the preferred mixing method is to dissolve the alkali metal citrate in water, alcohol, acetone or the like, and add the resulting solution to PVD.
It is a method of mixing with C, GME, an epoxy stabilizer and a plasticizer using a mixer. The composition of the present invention includes, in a range that does not impair the object of the present invention, a colorant such as a pigment known as an additive for food packaging, a stabilizer such as rot and antioxidant, an inorganic powder such as silica, a lubricant, MBS. A resin or the like can be added.

[Radiation Irradiation] The composition of the present invention can be molded by a usual method such as melt molding, and irradiated with radiation to form a molded product (hereinafter abbreviated as “single molded product”). The present invention also relates to a multilayer molded product (hereinafter referred to as "multilayer molded product") containing a layer composed of the composition of the present invention and composed of a single molded product irradiated with radiation and a layer composed of a thermoplastic resin.
And abbreviated). Irradiation has the effect of cross-linking the molded article made of the composition of the present invention and making it excellent in heat resistance.

The present invention includes α rays, β rays, electron rays, γ rays, Χ
Known radiation such as rays can be used, but from the viewpoint of the crosslinking effect before and after irradiation, electron rays and γ rays are preferable,
Among them, the electron beam is convenient in terms of handleability in producing a molded product. The irradiation conditions of the radiation may be appropriately set according to the target molded product. For example, in the case of an electron beam, the acceleration voltage is in the range of 250 to 500 kilovolts, and the irradiation dose is 10 to 200. The range of kilogray (hereinafter abbreviated as “KGy”) is preferable, and γ
In the case of a line, the dose rate is preferably in the range of 0.05 to 3 KGy / hour.

In the present invention, the degree of radiation irradiation can be evaluated by the gel fraction of the molded product (the measuring method will be described later). That is, the gel fraction of the single molded product in the present invention or the single molded product in the multilayer molded product is 0.
The range is 5 to 50%, preferably 1 to 20%, and more preferably 1 to 10%. Gel fraction 0.5%
If it is less than 50%, the heat resistance of the molded product is not sufficient,
If the gel fraction exceeds, there is a problem in producing a molded product such as long irradiation, and the mechanical properties of the resulting molded product may deteriorate. Gel fraction 1-20
The range of% is convenient from the viewpoint of performance such as manufacturability, heat resistance, and mechanical properties, and in particular, the range of 1 to 10% of gel fraction is also practical from the viewpoint.

[Molded Article] The molded article of the present invention is molded and produced by a usual method, and may be a single molded article or a multilayer molded article. In the case of a single molded product, for example, the above composition is hot pressed to produce a film or sheet, or the above composition is melt extruded, and the obtained extrudate is formed into a film or sheet by an inflation method, or the above composition. Melt-extruded by T-die method,
A film or sheet can be produced from the obtained extrudate. In addition, a multilayer resin such as a multilayer film or a multilayer sheet can be manufactured by laminating a thermoplastic resin on the film or sheet thus obtained and, if necessary, using an adhesive. Alternatively, using multiple extruders,
Using the composition of the present invention, a thermoplastic resin and, if necessary, an adhesive, coextrusion, and the resulting extrudate can be used to produce a multilayer molded product such as a multilayer film or a multilayer sheet by an inflation method or a T-die method. it can. Furthermore, above,
A film or sheet, or a multi-layer film or multi-layer sheet can be used to form a molded article into a container or the like. The single molded product and the multilayer molded product of the present invention may be unstretched or may be stretched.
The stretched product may be uniaxially stretched or biaxially stretched. The draw ratio is
It can be appropriately determined according to the purpose of the molded product, and normally, about 1.5 to 7 times in both the longitudinal and transverse directions is convenient.

The irradiation of radiation of the present invention is carried out in the process of producing the above-mentioned single molded product or multilayer molded product, from the extruded product obtained by melt-extruding the composition of the present invention to the film or sheet. If it is, it may be performed in any step. Specific examples include irradiation of the extrudate before inflation, irradiation of radiation during inflation, irradiation of the unstretched product after inflation, and unstretched product after extrusion with a T-die. Examples thereof include those that are irradiated with radiation, those that are simultaneously subjected to stretching and irradiation, and those that are irradiated with radiation after stretching. Among these, those that irradiate the extrudate before inflation, those that irradiate the unstretched product after inflation, those that irradiate the unstretched product after extrusion with a T-die, those that irradiate after stretching Etc. are preferable from the viewpoint of operation when they are manufactured.

The multilayer molded article of the present invention may be any one as long as it comprises a layer of a molded article made of the composition of the present invention and crosslinked by irradiation with radiation and a layer of a thermoplastic resin,
The thermoplastic resin used and the stacking order can be appropriately determined according to the purpose. In such a case, the adhesive force between the layers to be laminated may not be sufficient depending on the resin used and the laminating order. In such a case, a known adhesive resin such as a modified polyolefin or an ionomer resin described later is used. (Adhesive) can be used for strong adhesion. In the present invention, the adhesive agent is not included in the number of layers.

As the thermoplastic resin used in the present invention, known resins such as olefin polymers, amide polymers and polyesters can be used. Examples of the olefin polymer include homopolymers and copolymers of olefins, copolymers of olefins with other copolymerizable monomers such as vinyl monomers, and modified polymers thereof. can do. Specifically, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene (hereinafter "VLDPE")
Abbreviated), polypropylene, ethylene / propylene copolymer, ionomer resin, ethylene / vinyl acetate copolymer (hereinafter abbreviated as “EVA”), ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer (hereinafter “ EM
Abbreviated as “AA”), ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, modified polyolefin (for example, homo- or copolymer of olefins, and unsaturated carboxylic acid such as maleic acid or fumaric acid). And acid anhydrides and esters or reaction products with metal salts, etc.) and the like. In addition, polyolefins such as polyethylene and polypropylene obtained by using a metallocene catalyst (single-site catalyst) can also be suitably used. The above olefin polymers may be used alone or in combination of two or more. Among these, VLDPE, EVA, EMAA, linear low-density polyethylene, ethylene / acrylic acid copolymer and the like are preferable from the viewpoint of the physical properties of the obtained molded product.

As the amide polymer, nylon-6 (polycapramide), nylon-66 (polyhexamethyleneadipamide), nylon-610 (polyhexamethylenesebacamide), nylon-12 (lauryllactam ring-opening polymer) ), Nylon-6 / 66 (copolymer of ε-caprolactam and hexamethylene adipamide), nylon-6 / 610 (copolymer of ε-caprolactam and hexamethylene sebacamide), nylon-6 / 12 (ε
-Copolymer of caprolactam and lauryllactam), nylon-6 / 66/610 (copolymer of ε-caprolactam, hexamethyleneadipamide and hexamethylenesebacamide), nylon-6 / 66/12 (ε-caprolactam, Examples include hexamethylene adipamide and lauryl lactam copolymer), nylon-MXD6 (polymethaxylylene adipamide), nylon-6I / 6T (copolymer of hexamethylene isophthalamide and hexamethylene terephthalamide). be able to. Among these, nylon-6 / 66 and nylon-6 / 12 are preferable in terms of moldability, and nylon-MXD6 is preferable in terms of oxygen gas barrier property. The above amide polymers can be used alone or in combination of two or more.

As the polyester, for example, polyethylene terephthalate, polybutylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, or the like can be used.

In the multilayer molded article of the present invention, examples of the layer structure include the following. (1) Molded product layer / adhesive layer / olefin polymer layer of the present invention, (2) Molded product layer / adhesive layer / amide polymer layer of the present invention, (3) Olefin polymer layer / adhesion Agent layer / molded product layer of the present invention / adhesive layer / olefin polymer layer,
(4) amide polymer layer / adhesive layer / molded product layer of the present invention / adhesive layer / amide polymer layer, (5) olefin polymer layer / adhesive layer / molded product layer of the present invention / Adhesive layer / amide-based polymer layer, (6) olefin-based polymer layer / adhesive layer / molded product layer / adhesive layer / amide-based polymer layer / adhesive layer / olefin-based polymer layer of the present invention, (7) Olefin polymer layer / olefin polymer layer / adhesive layer / molded product layer of the present invention / adhesive layer / olefin polymer layer / olefin polymer layer.

Among the above-mentioned layer constitutions, the following can be exemplified as preferable ones. (8) VLDPE layer / EMAA layer / adhesive layer / molded product layer / adhesive layer / EMAA layer / VLDPE layer of the present invention,
(9) VLDPE layer / EMAA layer / adhesive layer / molded product layer / adhesive layer / EVA layer / VLDPE layer of the present invention, (1
0) VLDPE layer / EVA layer / adhesive layer / molded product layer / adhesive layer / EVA layer / EVA layer of the present invention, (11) EVA
Layer / EVA layer / adhesive layer / molded article layer of the present invention / adhesive layer / EVA layer / EVA layer.

The molded product of the present invention, in the case of a single molded product, has a thickness in the range of 5 to 2000 μm, preferably 10 to 10
It is in the range of 00 μm, more preferably in the range of 15 to 500 μm. When the thickness is less than 5 μm, the oxygen gas barrier property is largely deteriorated, and when the thickness exceeds 2000 μm, the obtained molded product becomes expensive and it becomes impossible to form a flexible packaging material. I have a problem. The thickness is preferably in the range of 10 to 1000 μm from the viewpoint of the above-mentioned production and performance balance, and particularly 15 to 50 μm.
The range of 0 μm is convenient from a practical viewpoint.

In the case of a multilayer molded product, the thickness is 10 to 10.
The range is 3000 μm, preferably 15 to 2000 μm, and more preferably 20 to 1000 μm. When the thickness is less than 10 μm, it is difficult to balance the oxygen gas barrier property and the impact strength, while the thickness is 300
When it exceeds 0 μm, for example, the secondary workability in molding a container or the like from the obtained film or sheet becomes difficult.
From the viewpoint of moldability and physical properties, the thickness is preferably in the range of 15 to 2000 μm, and particularly, the thickness is in the range of 20 to 1000 μm.
It is also suitable for practical use. The thickness of the molded product layer of the present invention in the multilayer molded product is in the range of 2 to 600 μm, preferably 3 to 500 μm, and more preferably 4 to 300.
It is in the range of μm. When the thickness is less than 2 μm, there is a problem in the oxygen gas barrier property, while when the thickness exceeds 600 μm, the obtained molded product becomes expensive, and
Secondary workability becomes difficult. From the viewpoint of production and performance, the thickness of the molded product layer of the present invention in the multilayer molded product is preferably in the range of 3 to 500 μm, and particularly preferably in the range of 4 to 300 μm for practical use.

[Use of Molded Product] The molded product of the present invention, for example, a film, a sheet or a container can be used as a packaging material for foods, pharmaceuticals and the like, and particularly,
Most suitable for food packaging such as ham, sausage or various meats. It can be used in a suitable form depending on the intended packaging such as a bag, a cylinder or a dish.

[0035]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The physical property measuring methods and resin materials used in the present invention are as follows.

<Physical property measuring method> (1) Discoloration or degree of coloring Σ80 Color Meas manufactured by Nippon Denshoku Industries Co., Ltd.
uring System, the sample color difference (L
*, A *, b *) was measured. The L * value means lightness, and a larger value indicates a direction in which the brightness is increased (whiter), and a smaller value indicates a direction in which the darkness is increased (blackened). The a * and b * values mean the chromaticity that expresses hue and saturation, and the a * value indicates a direction in which the reddishness increases as the plus value increases, and the greenness increases as the minus value increases. Indicates the direction of strengthening. As the b * value increases, the more positive the value, the stronger the yellowish color, and the larger the negative value,
Indicates the direction in which the bluish color becomes stronger. (2) Measurement of gel fraction In the case of a single molded product, about 70 mg of a sample was added to 10 ml of tetrahydrofuran and kept at 60 ° C. for 2 hours.
The undissolved material was collected, the dry amount thereof was measured, and it was determined as a percentage from the dry mass of the undissolved material with respect to the added sample mass. In the case of a multilayer molded product, the PVDC layer, which is the molded product portion of the present invention, was peeled off, and this was used as a sample for measurement by the same method as above.

(3) Measurement of thermal stability A sample measuring 2 cm in length and 3 cm in width was cut out from the sample and placed in a hot air dryer adjusted to 150 ° C., and after 60 minutes, the sample was taken out from Nippon Denshoku Industries Co., Ltd. ) Made Σ8
The color difference (L *, a *, b *) was measured using a 0 Color Measuring System to evaluate the degree of discoloration of the sample. (4) Impact strength The puncture strength of the heat-sealed portion was evaluated. That is, from the inside of a bag of 400 mm in length and 400 mm in width (opened on the side opposite to the seal portion) obtained by heat sealing in a direction substantially perpendicular to the film taking direction, along the seal line, as a lubricating oil After applying, the diameter of the tip connected to the load cell made by Orientec Co., Ltd. is 1
The seal part was punched out from the inside of the bag with a punching rod having a 0 mm ball, and the strength (kg) at the time of punching out was read. Punching was performed at three points on one bag, this was performed on ten bags, and the punching strengths at 30 points were averaged by making them meet. (5) Oxygen permeability Using an oxygen permeability measuring device OXTRAN-100 manufactured by Modern Control Co., Ltd., 30 ° C., 100%
It was measured under the conditions of relative humidity.

<Resin Material> (1) PVDC A copolymer composed of 82% by mass of vinylidene chloride and 18% by mass of vinyl chloride (reduced viscosity: 0.056 L / g, hereinafter referred to as “P”).
A copolymer composed of 95% by mass of vinylidene chloride and 5% by mass of methyl acrylate (reduced viscosity = 0.039 L / g, hereinafter abbreviated as "PVDC-2") was used. (2) VLDPE V0398CN manufactured by Idemitsu Petrochemical Co., Ltd. (density = 0.907)
g / cm ³ , melting point = 119 ° C.) was used. (3) EMAA Nucrel AN421 manufactured by DuPont Mitsui Polychemicals
7-1C was used. (4) EVA NUC1868 manufactured by Nippon Unicar Co., Ltd. (vinyl acetate content =
18% by mass), NUC3715 (vinyl acetate content = 16
Mass%) and FB-821 (vinyl acetate content = 10 mass%). (5) Adhesive Resin Evatate PC-149 (vinyl acetate content = 15% by mass) manufactured by Sumitomo Chemical Co., Ltd. was used.

[Examples 1 to 6, Comparative Examples 1 to 10] 100
With respect to parts by mass of PVDC-1, the amount of glycerin monostearate (hereinafter abbreviated as “GMS”) shown in Table 1 and epoxidized soybean oil 1.5 as an epoxy stabilizer
Parts by weight, 1.0 part by weight of epoxidized linseed oil, and 1.0 part by weight of dibutyl sebacate as a plasticizer were added and mixed at 80 ° C. for 15 minutes using a mixer, and then 50 ° C.
Each composition was prepared by holding it in an oven for 24 hours. The composition thus obtained was preheated for 1 minute at 150 ° C. using a compression molding machine and then pressurized for 1 minute,
Then, it was rapidly cooled to prepare an amorphous press sheet having a thickness of 200 μm.

Then, using NHV EPS-500-65-SS as an electron beam irradiation device, the above sheet was irradiated with an electron beam under the following conditions. Using the sheet thus obtained, the color difference (L *, a *, b *) and the gel fraction for evaluating the degree of discoloration or coloring were measured. The results are summarized in Table 1. Electron beam irradiation conditions Irradiation temperature 23 ° C. Irradiation atmosphere Air accelerating voltage 275 kilovolts Irradiation amount 20 KGy or 40 KGy Among the sheets obtained by using the above composition, those not subjected to electron beam irradiation are shown in Table 1. Irradiation dose
0 KGy ”.

[0041]

[Table 1]   ───────────────────────────────────                   Amount of addition Irradiation Degree of discoloration or coloring Gel fraction                  (Mass part) (KGy) L * value a * value b * value (%)   ───────────────────────────────────     Comparative Example 1 GMS 0 86.9 1.0 4.2 0     Comparative Example 2 0 40 86.5 0.6 7.1 2   ───────────────────────────────────     Comparative Example 3 GMS 0.01 0 87.0 0.9 4.2 0     Comparative Example 4 0.01 20 87.0 0.7 6.0 2     Comparative Example 5 0.01 40 86.8 0.6 7.2 3   ───────────────────────────────────     Comparative Example 6 GMS 0.5 0 87.5 1.0 4.6 0     Example 1 0.5 20 87.8 0.1 6.3 2     Example 2 0.5 40 87.4 -0.1 8.0 3   ───────────────────────────────────     Comparative Example 7 GMS 1.50 87.6 0.9 4.5 0     Example 3 1.5 20 87.5 0.0 6.2 2     Example 4 1.5 40 87.2 -0.1 8.0 3   ───────────────────────────────────     Comparative Example 8 GMS 2.00 87.5 0.8 4.6 0     Example 5 2.0 20 87.4 -0.1 6.3 2     Example 6 2.0 40 87.2 -0.2 7.9 3   ───────────────────────────────────     Comparative Example 9 GMS 3.0 0 87.5 0.9 4.8 0     Comparative Example 10 3.0 40 87.1 -0.2 7.8 3   ───────────────────────────────────

From Table 1, for example, Example 1 or Example 2 has a smaller a * value than the corresponding Comparative Example 6,
As can be seen from the reduction in redness, the sheets of the present invention (Examples 1 to 6) are improved in the degree of discoloration or coloring as compared with the corresponding Comparative Examples. From this, GMS has an effect of preventing discoloration or coloring due to electron beam irradiation. In Comparative Examples 9 and 10, there was a lot of cloudiness with a diameter of about 0.5 mm on the sheet, and there was a problem in using it as a sheet.

[Examples 7-8, Comparative Examples 11-23] 10
With respect to 0 part by mass of PVDC-1, 1.0 part by mass of the additives shown in Table 2, 1.5 parts by mass of epoxidized soybean oil as an epoxy stabilizer and 1.0 part by mass of epoxidized linseed oil, a plasticizer Then, 1.0 part by mass of dibutyl sebacate was added thereto, the composition was adjusted in the same manner as in Example 1, and an amorphous press sheet was prepared, followed by electron beam irradiation. Using the sheet thus obtained, the color difference (L *, a
*, B *) and gel fraction were measured. The results are summarized in Table 2. As additives, GMS, glycerin monoacetate (hereinafter abbreviated as "GMA"), glycerin monolaurate (hereinafter abbreviated as "GML"), glycerin trioleate (hereinafter abbreviated as "GTO"), glycerin Tristearate (hereinafter "G
(Abbreviated as "TS").

[0044]

[Table 2]   ───────────────────────────────────               Additives Additive amount Irradiation Degree of discoloration or coloring Gel fraction                      (Mass part) (KGy) L * value a * value b * value (%)   ───────────────────────────────────     Comparative Example 11 GMS 1.00 87.5 1.0 4.6 0     Example 7 1.0 20 87.8 0.1 6.3 2     Example 8 1.0 40 87.4 -0.1 8.0 3   ───────────────────────────────────     Comparative Example 12 GMA 1.00 86.7 0.9 4.5 0     Comparative Example 13 1.0 20 84.1 2.4 4.6 2     Comparative Example 14 1.0 40 81.2 3.3 5.4 3   ───────────────────────────────────     Comparative Example 15 GML 1.00 86.2 1.0 5.8 0     Comparative Example 16 1.0 20 83.4 4.8 4.4 2     Comparative Example 17 1.0 40 80.3 7.8 4.1 3   ───────────────────────────────────     Comparative Example 18 GTO 1.00 86.6 1.0 5.2 0     Comparative Example 19 1.0 20 81.9 4.5 3.0 2     Comparative Example 20 1.0 40 78.8 7.4 3.3 3   ───────────────────────────────────     Comparative Example 21 GTS 1.00 86.5 0.9 4.7 0     Comparative Example 22 1.0 20 81.6 4.8 3.3 2     Comparative Example 23 1.0 40 78.4 7.6 3.6 3   ───────────────────────────────────

From Table 2, Example 7 or Example 8
Compared to the corresponding Comparative Example 11, the a * value is smaller and the redness is reduced. For example, Comparative Example 13 or Comparative Example 1
It can be seen that sample No. 4 has a larger a * value and more redness than comparative example 12. From this, GMA, GML, GTO, or GTS other than GMS has no effect of preventing discoloration or coloring due to electron beam irradiation.

[Examples 9 to 10, Comparative Example 24] 1.0 part by mass of GMS, 1.5 parts by mass of epoxidized soybean oil as an epoxy stabilizer and 1 part of epoxidized linseed oil per 100 parts by mass of PVDC-2. 0.0 parts by mass and 1.0 part by mass of dibutyl sebacate as a plasticizer were added, the composition was adjusted in the same manner as in Example 1, and an amorphous press sheet was prepared and then irradiated with an electron beam. The color difference (L *, a *, b *) and the gel fraction were measured using the sheet thus obtained. The results are summarized in Table 3.

[0047]

[Table 3] ────────────────────────────────── Addition dose Irradiation Degree of discoloration or coloring Gel fraction (Parts by mass) (KGy) L * value a * value b * value (%) ──────────────────────────────── Comparative Example 24 GMS 1.00 86.5 0.8 3.5 0 Example 9 1.0 20 86.3 -0.1 5.2 2 Example 10 1.0 1.0 40 86.2 -0.2 6.5 3 ─────────── ─────────────────────── Table 3 shows that PVDC with different resin composition (monomer composition) prevents discoloration or coloration due to electron beam irradiation of GMS. It is also shown to be effective.

[Example 11, Comparative Example 25] 1.3 parts by mass of GMS, 1.0 part by mass of epoxidized soybean oil as an epoxy stabilizer, and 0.8 parts of epoxidized linseed oil as an epoxy-based stabilizer based on 100 parts by mass of PVDC-1. Parts by mass, 8.0 parts by mass of dibutyl sebacate as a plasticizer, and 0.5 parts by mass of sodium citrate in a warm water of the same amount are added, and the mixture is mixed at 80 ° C. for 15 minutes using a mixer. The composition was then prepared by holding it in an oven at 50 ° C. for 24 hours. The composition thus obtained was preheated for 1 minute at 150 ° C. using a compression molding machine and then pressed for 1 minute to prepare an amorphous press sheet having a thickness of 200 μm. This sheet was cut in half, and one sheet was irradiated with an electron beam as in Example 1 (however, the irradiation amount was 40 KGy),
The color difference (L *, a *, b *) and the gel fraction of the obtained sheet were measured. On the other hand, the remaining sheets were subjected to a thermal stability test. In addition, as a comparative example, in the same manner as in Example 9 except that GMS and sodium citrate were not added,
The color difference (L *, a *, b *) and gel fraction were measured and a thermal stability test was performed (Comparative Example 25). The results thus obtained are summarized in Table 4.

[0049]

[Table 4] ────────────────────────────────── Thermal stability Discoloration or coloration degree Gel fraction L * Value a * Value b * Value L * Value a * Value b * Value (%) ─────────────────────────────── ──── Comparative Example 25 67.5 3.0 49.0 86.5 0.6 7.1 2 Example 11 71.5 -1.6 42.7 87.7 -0.2 7.5 3 ──────────────────────── ────────── From Table 4, the addition of sodium citrate is effective in improving the thermal stability of the sheet, and when used in combination with GMS, discoloration or coloring due to electron beam irradiation is prevented. I understand that

[Example 12, Comparative Example 26] The PVDC composition, VLDPE, EMAA and adhesive resin prepared in Example 1 were coextruded in the following layer constitution to obtain an extrudate. Then, from the surface of this extrudate, using the electron beam irradiation apparatus used in Example 1, a dose of 110 KGy,
Electron beam irradiation was performed at an accelerating voltage of 275 kilovolts.
Then, the tube film having a folding width of 400 mm was manufactured by stretching the film in the lengthwise direction and the widthwise direction by 3 times by an inflation method (Example 12). Furthermore, this tube film was heat-sealed in a direction substantially perpendicular to the take-up direction, and had a size of 400 mm in length and 400 mm in width.
A bag having an open side opposite to the heat-sealed portion was manufactured. In addition, as a comparative example, PVDC prepared in Comparative Example 1
A tube film and a bag therefrom were produced in the same manner as in Example 12 except that the composition was used (Comparative Example 26).
Oxygen permeability, color difference (L
*, A *, b *) and gel fraction, also using a bag,
The impact strength (piercing strength) of the sealed portion was measured. The results are shown in Table 5.

<Layer constitution> VLDPE layer (outermost layer) / EM
AA layer (outer layer) / adhesive layer / PVDC layer / adhesive layer / E
MAA layer (inner layer) / VLDPE layer (innermost layer) <Thickness (μm) of each layer> Extruded product 27 (outermost layer) /189/13.5/63/13.5/
90/90 (innermost layer) Film 3 (outermost layer) /21/1.5/7/1.5/10/10
(Innermost layer)

[0052]

[Table 5]   ───────────────────────────────────                           Physical properties of tube film PVDC layer             ────────────────────────────              Oxygen permeability Impact strength Degree of discoloration or coloring Gel fraction             (ml / m2 ・ day ・ atm) (kg) L * value a * value b * value (%)   ───────────────────────────────────     Comparative Example 26 38 8.4 88.6 2.3 4.9 2     Example 12 35 12 89.2 0.8 4.0 2   ───────────────────────────────────

[Example 13 and Comparative Example 27] The PVDC composition, VLDPE, EVA and adhesive resin prepared in Example 1 were coextruded in the following layer constitution to obtain an extrudate. Next, using the electron beam irradiation device used in Example 1, electron beam irradiation was performed from the surface of this extruded product at an irradiation amount of 80 KGy and an acceleration voltage of 275 kilovolts. Then, the tube film having a folding width of 400 mm was manufactured by stretching the film vertically and horizontally three times by the inflation method (Example 13). Further, using this tube film, heat-sealing was carried out in a direction substantially perpendicular to the take-up direction to produce a bag having a size of 400 mm in length and 400 mm in width, the side opposite to the heat-sealed portion being open.
In addition, as a comparative example, a tube film and a bag therefrom were manufactured in the same manner as in Example 13 except that the PVDC composition prepared in Comparative Example 1 was used (Comparative Example 27). Using the above tube film, oxygen permeability, color difference (L *,
a *, b *) and gel fraction, and the impact strength (piercing strength) of the sealed portion was measured using a bag. The results are shown in Table 6.

<Layer constitution> VLDPE layer (outermost layer) / EV
A layer (outer layer) / adhesive layer / PVDC layer / adhesive layer / EV
A layer (inner layer) / EVA layer (inner layer) However, EVA of the outer layer is NUC1868, EVA of the inner layer
Is NUC3715, and the innermost EVA is FB-821.
Was used. <Thickness of each layer (μm)> Extruded product 27 (outermost layer) /189/13.5/63/13.5/
90/90 (innermost layer) Film 3 (outermost layer) /21/1.5/7/1.5/10/10
(Innermost layer)

[0055]

[Table 6]   ───────────────────────────────────                           Physical properties of tube film PVDC layer             ────────────────────────────              Oxygen permeability Impact strength Degree of discoloration or coloring Gel fraction             (ml / m2 ・ day ・ atm) (kg) L * value a * value b * value (%)   ───────────────────────────────────     Comparative Example 27 39 5.9 88.7 2.0 4.8 2     Example 13 35 8.3 89.5 0.7 3.8 2   ───────────────────────────────────

[0056]

INDUSTRIAL APPLICABILITY The PVDC molded product of the present invention is excellent in prevention of discoloration and discoloration, thermal stability, impact strength and heat resistance, and is most suitable as a packaging material for foods, pharmaceuticals and the like. The PVDC molded product of the present invention can be used as a film, a sheet, a container, or the like.

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-6-192523 (JP, A) JP-A-6-220284 (JP, A) JP-A-53-23331 (JP, A) JP-A-6- 328634 (JP, A) JP 58-40337 (JP, A) JP 58-162648 (JP, A) JP 55-99943 (JP, A) JP 56-38342 (JP, A) JP-A-8-239493 (JP, A) JP-A-5-255560 (JP, A) JP-A-3-35043 (JP, A) JP-A-5-230310 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 27/08 C08J 5/18

Claims (8)

(57) [Claims] 1. A glycerin monofatty acid ester having a fatty acid having 16 to 22 carbon atoms in an amount of 0.05 to 2.5 parts by mass and an epoxy stabilizer in an amount of 0.05 to 4 parts by mass with respect to 100 parts by mass of a vinylidene chloride polymer. Parts and a composition containing 0.1 to 10 parts by mass of a plasticizer, and a irradiated vinylidene chloride polymer molded product. 2. The molded product according to claim 1, wherein the glycerin monofatty acid ester is at least one selected from the group consisting of glycerin monostearate, glycerin monopalmitate and glycerin monobehenate. 3. The vinylidene chloride-based polymer 10 is a composition.
The molding according to claim 1 or 2, further comprising 0.01 to 3 parts by mass of at least one alkali metal citrate selected from the group consisting of sodium citrate and potassium citrate, relative to 0 parts by mass. object. 4. A molded product comprising a layer composed of the molded product according to any one of claims 1 to 3 and a layer composed of a thermoplastic resin. 5. The molded product according to claim 4, wherein the thermoplastic resin is an olefin polymer or an amide polymer. 6. The molded product according to claim 1, which is a film or a sheet. 7. The molded product according to claim 1, wherein the gel fraction is in the range of 0.5 to 50%. 8. The molded product according to claim 1, wherein the radiation is an electron beam.