JP2014214197A - Vinylidene chloride-based resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinylidene chloride-based resin molded article excellent in thermal stability, barrier properties, and transparency.SOLUTION: A vinylidene chloride-based resin-molded article is formed of a vinylidene chloride-based resin composition containing a vinylidene chloride-based copolymer, a thermal stabilizer containing a copolymer of a monomer having a glycidyl group and a monomer having no glycidyl group, and an antioxidant and/or a fatty acid. The vinylidene chloride-based resin composition contains 0.1-5 pts.wt. of the thermal stabilizer with respect to 100 pts.wt. of the vinylidene chloride-based copolymer, and the amount of the left monomer having the glycidyl group is 4 mg/kg or less.

Description

  The present invention relates to a vinylidene chloride resin molded article.

  As vinylidene chloride resin compositions, those containing vinylidene chloride copolymers and appropriate amounts of additives such as plasticizers and stabilizers are generally known. Molded products (vinylidene chloride-based resin molded products) obtained by melt-molding this vinylidene chloride-based resin composition are particularly excellent in oxygen barrier properties, moisture resistance, transparency, chemical resistance, oil resistance, etc. Therefore, it is used for a wide variety of uses such as food packaging and pharmaceutical packaging.

  However, at present, only a very small amount of a liquid additive (plasticizer) can be added to a vinylidene chloride-based resin molded product in order to maintain the protruding barrier property. In addition, the liquid additive after addition is extracted or transferred when the vinylidene chloride copolymer is molded into a packaging material such as a film or container, affected by the storage environment and the contents to be filled (packaged material). There is a risk of doing so. Therefore, from the viewpoint of food hygiene, it is considered preferable to keep the addition amount of the liquid additive to a very small amount. Under these circumstances, the conventional vinylidene chloride resin composition and the vinylidene chloride resin molded product have very poor thermal stability during melt molding, for example, extrusion film formation, in other words, maintain a high barrier property. Then, in order to suppress the transfer of additives to food, thermal stability and productivity were sacrificed.

  Therefore, a polymer additive having a heat stabilizing effect is blended with the vinylidene chloride copolymer for the purpose of realizing high thermal stability with high barrier properties, low transferability of additives to foods, and high heat stability. Attempts have been made. For example, Patent Document 1 describes a vinylidene chloride composition containing a glycidyl methacrylate polymer having an epoxy value of at least 0.3 as a heat stabilizer. Patent Document 2 describes a polyvinylidene chloride resin composition containing a (meth) acrylic resin having a glycidyl group as a heat stabilizer.

JP-A-5-148398 JP 2003-26882 A

  However, the thermal stability of the vinylidene chloride-based resin composition described in Patent Documents 1 and 2 is not sufficient for continuous extrusion over a long period of time, and to ensure acceptable quality and productivity in actual production. Tend to be difficult.

  This invention is made | formed in view of the said situation, The objective is to provide the vinylidene chloride type-resin molded product which is excellent in thermal stability, barrier property, and transparency.

  As a result of intensive research, the present inventors have been melt-formed using a vinylidene chloride-based resin composition containing a heat stabilizer containing a copolymer having a glycidyl group, and an antioxidant and / or a fatty acid. The present inventors have found that the above-mentioned problems can be solved by employing a vinylidene chloride-based resin molded product, and have completed the present invention.

That is, the present invention provides the following (1) to (7).
(1) It includes a vinylidene chloride copolymer, a heat stabilizer containing a copolymer of a monomer having a glycidyl group and a monomer having no glycidyl group, and an antioxidant and / or a fatty acid. A vinylidene chloride-based resin molded article formed from a vinylidene chloride-based resin composition, wherein the vinylidene chloride-based resin composition is 0.1 to 5 parts by weight of a heat stabilizer with respect to 100 parts by weight of a vinylidene chloride-based copolymer. A molded product comprising the vinylidene chloride-based resin molded product and having a monomer having a glycidyl group remaining in an amount of 4.0 mg / kg or less.
(2) The copolymer according to (1), wherein the copolymer is a copolymer of 30 to 75% by weight of a monomer having a glycidyl group and 25 to 70% by weight of a monomer having no glycidyl group. Molding.
(3) The molded article according to (1) or (2), wherein the monomer having no glycidyl group contains at least one selected from the group consisting of styrene and (meth) acrylic acid esters.
(4) The vinylidene chloride resin according to any one of (1) to (3), wherein the antioxidant is at least one selected from the group consisting of phenolic antioxidants and hindered phenolic antioxidants. Molding.
(5) The vinylidene chloride resin molded article according to any one of (1) to (4), wherein the antioxidant contains at least α-tocopherol.
(6) The vinylidene chloride resin molded article according to any one of (1) to (5), wherein the fatty acid is at least one selected from the group consisting of stearic acid, palmitic acid and erucic acid.
(7) The vinylidene chloride resin molding according to any one of (1) to (6), comprising a vinylidene chloride resin composition in which the amount of the monomer having a glycidyl group remaining is 0.1 mg / kg or less. Goods.

  ADVANTAGE OF THE INVENTION According to this invention, the vinylidene chloride resin composition molded article excellent in thermal stability, barrier property, and transparency can be provided. The vinylidene chloride-based resin composition molded product can be produced by continuous extrusion molding and has excellent hygiene suitable for food packaging.

It is the schematic which shows one Embodiment of the manufacturing apparatus which produces a vinylidene chloride-type resin molded product.

  Hereinafter, embodiments of the present invention will be specifically described. In addition, the following embodiment is an illustration for demonstrating this invention, and this invention is not limited only to the embodiment.

[Vinylidene chloride resin composition]
The vinylidene chloride-based resin composition of the present embodiment includes a thermal stabilizer (hereinafter referred to as a heat stabilizer) containing a vinylidene chloride-based copolymer and a copolymer of a monomer having a glycidyl group and a monomer having no glycidyl group. A stabilizer (A)), an antioxidant (hereinafter referred to as an antioxidant (B)) and / or a fatty acid (hereinafter referred to as a fatty acid (C)).

(Vinylidene chloride copolymer)
In the present embodiment, the vinylidene chloride copolymer means a copolymer of vinylidene chloride as a main component and an unsaturated monomer copolymerizable with the vinylidene chloride.

  Examples of the unsaturated monomer include alkyl acrylate esters (alkyl having 1 to 18 carbon atoms) such as methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, and methacrylic acid. Methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, alkyl methacrylates such as lauryl methacrylate (alkyl having 1 to 18 carbon atoms), vinyl cyanide such as acrylonitrile and methacrylonitrile, and fragrance such as styrene Group vinyl, vinyl chloride, isobutylene, vinyl acetate and the like, but are not particularly limited thereto. Among these, vinyl chloride, methyl acrylate, butyl acrylate or 2-ethylhexyl acrylate is preferable. In addition, an unsaturated monomer may be used individually by 1 type, or may use 2 or more types together.

  The copolymerization ratio of vinylidene chloride in the vinylidene chloride copolymer is preferably 70% by weight to 98% by weight, and more preferably 80% by weight to 97% by weight. If the copolymerization ratio of vinylidene chloride is 70% by weight or more, the recrystallization speed after melting is fast, the film forming processability is improved, and if the copolymerization ratio of vinylidene chloride is 98% by weight or less, Since the internal plasticizing effect by the polymerization monomer component is obtained, the melt processability is improved.

  The vinylidene chloride copolymer may be obtained by any polymerization method such as suspension polymerization, emulsion polymerization or solution polymerization, but is preferably obtained by suspension polymerization.

  The weight average molecular weight (Mw) of the vinylidene chloride copolymer is not particularly limited, but is preferably 50,000 to 150,000, and more preferably 60,000 to 130,000. Moreover, it is good also as a composition of the vinylidene chloride type | system | group copolymer adjusted so that Mw may become the range of 50,000-150,000 by mixing 2 or more types of vinylidene chloride type copolymers from which Mw differs in arbitrary ratios. . By setting Mw to 50,000 or more, it is possible to easily realize the strength that can withstand the film-forming stretch during melt molding and the mechanical strength of the molded product. On the other hand, when the Mw is 150,000 or less, the above-mentioned vinylidene chloride copolymer with the adjusted copolymerization ratio of vinylidene chloride, the thermal stabilizer (A), the antioxidant (B) and / or the fatty acid (C) is used. Can be combined to improve the thermal stability during melt molding. In the present specification, Mw of the vinylidene chloride copolymer is a gel permeation chromatography method (GPC) using a gel permeation chromatograph HLC-8020 manufactured by Tosoh Corporation with polystyrene as a standard. This is the required value.

  The weight average particle diameter of the vinylidene chloride copolymer is preferably 150 μm to 500 μm, more preferably 180 μm to 400 μm, and still more preferably 200 μm to 350 μm. When the weight average particle diameter is in the range of 150 μm to 500 μm, fluctuations in the extrusion load during extrusion molding are reduced, and stable extrusion is possible. The particle size distribution can be measured by a Coulter Multisizer particle measuring device TA-II type manufactured by Nikka Kikai Co., Ltd.

(Thermal stabilizer (A))
The heat stabilizer (A) is a copolymer of a monomer having a glycidyl group and a monomer having no glycidyl group.

  The monomer having a glycidyl group is preferably a vinyl-polymerizable unsaturated fatty acid glycidyl ester, for example, (meth) acrylic acid glycidyl ester such as glycidyl methacrylate, glycidyl acrylate, maleic acid, fumaric acid. And diglycidyl esters of carboxylic acids capable of vinyl polymerization such as itaconic acid. Among these, (meth) acrylic acid glycidyl ester is preferable. In addition, the monomer which has a glycidyl group may be used individually by 1 type, or may use 2 or more types together. The copolymerization ratio of the monomer having a glycidyl group is preferably 30% by weight to 75% by weight. When the copolymerization ratio of the monomer having a glycidyl group is 30% by weight or more, the thermal stability is improved and the barrier property is also improved by adding a small amount. Further, when the copolymerization ratio of the monomer having a glycidyl group is 75% by weight or less, the compatibility with the vinylidene chloride copolymer is good and the transparency is excellent.

  The monomer having no glycidyl group may be a compound copolymerizable with the monomer having the glycidyl group. For example, aromatic vinyl such as styrene, methyl acrylate, butyl acrylate, acrylic acid 2 -Acrylic acid alkyl esters (alkyl having 1 to 18 carbon atoms) such as ethylhexyl, lauryl acrylate, stearyl acrylate, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, etc. Examples include acid alkyl esters (alkyl having 1 to 18 carbon atoms), vinyl cyanide such as acrylonitrile and methacrylonitrile, vinyl chloride, isobutylene, and vinyl acetate. Especially, it is preferable that the monomer which does not have a glycidyl group contains at least 1 sort (s) chosen from the group which consists of styrene and (meth) acrylic acid ester. In addition, the monomer which does not have a glycidyl group may be used individually by 1 type, or may use 2 or more types together. The copolymerization ratio of the monomer having no glycidyl group is preferably 25% by weight to 70% by weight. If the copolymerization ratio is 25% by weight or more, the compatibility with the vinylidene chloride copolymer is good, and if it is 70% by weight or less, thermal stability is improved by adding a small amount.

  Although the weight average molecular weight (Mw) of a heat stabilizer (A) is not specifically limited, Preferably it is 50,000-100,000, More preferably, it is 8,000-50,000. The weight average molecular weight is preferably selected from the above range from the viewpoint of compatibility with the vinylidene chloride copolymer and generation of aggregates.

  The amount of the heat stabilizer (A) added is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the vinylidene chloride copolymer. If the addition amount is 0.1 parts by weight or more, the thermal stability during processing is improved, and if it is 5 parts by weight or less, the barrier property and transparency of the molded product are also improved.

  The vinylidene chloride resin composition of this embodiment can improve thermal stability by including an antioxidant (B) and / or a fatty acid (C) together with a thermal stabilizer (A).

(Antioxidant (B))
Examples of the antioxidant (B) include dibutylhydroxytoluene (BHT), triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] (Irganox 245) and the like. Representative phenolic antioxidants, thioether antioxidants typified by thiodipropionic acid, distearyl thiodipropionate, etc., phosphines typified by trisnonylphenyl phosphite, distearyl pentaerythritol diphosphite, etc. Examples thereof include phyto-based antioxidants and hindered phenol-based antioxidants represented by α-tocopherol. Among these, a phenolic antioxidant and a hindered phenolic antioxidant are preferable, and α-tocopherol is more preferable. An antioxidant (B) may be used individually by 1 type, or may use 2 or more types together. By adding an antioxidant, the heat resistance of the heat stabilizer (A) can be improved.

  The amount of the antioxidant (B) added is preferably 0.005 to 0.6 parts by weight, more preferably 0.006 to 0.5 parts by weight, based on 100 parts by weight of the vinylidene chloride copolymer. Preferably, 0.008 to 0.3 parts by weight is more preferable, 0.01 to 0.2 parts by weight is still more preferable, and 0.06 to 0.1 parts by weight is particularly preferable. If the amount of the antioxidant is 0.005 parts by weight or more, the thermal stability during molding of the vinylidene chloride resin composition is improved, the heat resistance of the thermal stabilizer (A) is also improved, and the molded product is The amount of residual monomer having a glycidyl group can be reduced to a level preferable for food packaging applications. Moreover, if the amount of the antioxidant (B) is 0.6 parts by weight or less, the transparency of the molded product will be good.

  The amount of the antioxidant (B) remaining in 100 parts by weight of the vinylidene chloride resin molded product is preferably 0.004 parts by weight to 0.5 parts by weight, more preferably 0.005 parts by weight to 0.4 parts by weight. Preferably, 0.008 weight part-0.2 weight part are still more preferable, 0.05 weight part-0.08 weight part is still more preferable. If the residual amount of the antioxidant (B) with respect to the vinylidene chloride-based molded product is 0.004 parts by weight or more, the coloration of the molded product over time during storage can be suppressed.

(Fatty acid (C))
Examples of fatty acids (C) include saturated fatty acids such as stearic acid, palmitic acid, and behenic acid, monounsaturated fatty acids such as myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, gadoleic acid, and erucic acid. Diunsaturated fatty acids such as linoleic acid and eicosadienoic acid, triunsaturated fatty acids such as linolenic acid and pinolenic acid, tetraunsaturated fatty acids such as stearidonic acid, and succinic acid Examples thereof include hexaunsaturated fatty acids such as pentaunsaturated fatty acid and docosahexaenoic acid. Of these, stearic acid, palmitic acid and erucic acid are preferred when the vinylidene chloride-based resin molded product is used for food packaging.

  By adding the fatty acid (C) to the vinylidene chloride copolymer, it reacts with the monomer having a glycidyl group remaining in the vinylidene chloride resin composition and has a glycidyl group remaining in the molded product. The amount of monomer can be reduced.

  The amount of the fatty acid (C) added is preferably 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.4 parts by weight, with respect to 100 parts by weight of the vinylidene chloride copolymer. 0.05 parts by weight to 0.3 parts by weight is more preferable. When the amount of the fatty acid (C) is 0.005 parts by weight or more, the amount of the monomer having a residual glycidyl group in the molded product can be reduced to a level preferable for food packaging applications. Moreover, if the amount of fatty acid (C) is 0.5 parts by weight or less, the polymer transportability during processing and the bag-making property of the molded product will be good.

  In the vinylidene chloride resin composition, a small amount of a monomer having a glycidyl group derived from the heat stabilizer (A) remains. In addition, when the vinylidene chloride-based resin composition containing the heat stabilizer (A) is molded by heat extrusion, a reaction in which the heat stabilizer (A) is depolymerized also proceeds simultaneously. With the reaction, a monomer having a glycidyl group is generated and remains in the molded product. If the amount of the monomer having a glycidyl group in the molded product is 4 mg / kg or less, it is possible to satisfy the food hygiene regulations of each country. The amount of the monomer having a glycidyl group in the molded product produced by depolymerization depends on the shape of the extrusion screw used during heat extrusion, the extrusion temperature conditions, etc., but the vinylidene chloride resin composition before molding It will increase about 10 to 40 times that of the monomer having a glycidyl group remaining in the product. Therefore, by setting the amount of the monomer having a glycidyl group in the vinylidene chloride-based resin composition to 0.1 mg / kg or less, the glycidyl group remaining in the molded product produced from the vinylidene chloride-based resin composition It is possible to achieve the amount of the monomer having a target value or less.

  The amount of the monomer having a glycidyl group remaining in the vinylidene chloride-based resin composition of the present embodiment needs to be 0.1 mg / kg or less. The amount of the monomer having a glycidyl group remaining in the vinylidene chloride-based resin composition can be measured as follows.

Acetone (10 mL) is added to 1 g of the heat stabilizer (A), followed by heat extraction at 50 ° C. for 1 hour to obtain an extract. This extract is analyzed by GC / MS (column: DB-WAX, 30 m × 0.25 mm × 0.25 μm), and the amount of the monomer having a glycidyl group in the heat stabilizer (A) is quantified. The amount of the monomer having a glycidyl group remaining in the vinylidene chloride-based resin composition depends on the amount of the monomer having a glycidyl group remaining in the heat stabilizer (A) and the addition amount of the heat stabilizer (A). Calculated from the following equation.
[Amount of monomer having glycidyl group remaining in vinylidene chloride-based resin composition (mg / kg)] = [Amount of monomer having glycidyl group remaining in heat stabilizer] × Addition amount / 100

  The amount of the monomer having a glycidyl group remaining in the vinylidene chloride-based resin molded product can be measured as follows.

  Acetone (10 mL) is added to 1 g of the molded product, and heat extraction is performed at 50 ° C. for 1 hour to obtain an extract. This extract is analyzed by GC / MS (column: DB-WAX, 30 m × 0.25 mm × 0.25 μm), and the amount of the monomer having a glycidyl group in the molded product is quantified.

  As described above, the amount of the monomer having the remaining glycidyl group can be adjusted by the addition amount of the antioxidant (B) or the fatty acid (C).

  The addition method of the heat stabilizer (A), the antioxidant (B) and the fatty acid (C) is not particularly limited, and a known method can be used, for example, heating with a high-speed Henschel mixer, a ribbon blender, or the like. The cooling mixing method is mentioned. Further, the heat stabilizer (A), the antioxidant (B) and / or the fatty acid (C) may be added separately or simultaneously, and these additions may be carried out in combination with vinylidene chloride. The polymer may be added before or after polymerization.

  In addition, the vinylidene chloride resin composition of the present embodiment, if necessary, is a different type of resin (including a polymer and a copolymer) or a thermal stabilizer different from the thermal stabilizer (A). Various additives such as a lubricant, a satin finish, and a pigment may be included.

  Specific examples of additives include polyester plasticizers represented by acetyl tributyl citrate, dibutyl sebacate, dioctyl sebacate, diacetylated monoglyceride, acetylated diglyceride, etc., epoxidized soybean oil, epoxidized linseed oil, Additives that are liquid at room temperature, such as heat stabilizers typified by epoxy compounds such as epoxidized octyl stearate, epoxidized palm oil, and bisphenol A diglycidyl ether. These liquid additives at normal temperature may be used alone or in a mixture of two or more, and can be added within a range that does not impair the barrier properties of the vinylidene chloride resin molded product.

  In addition, if necessary, a masking agent typified by an inorganic compound thermal stabilizer represented by sodium pyrophosphate, magnesium oxide, magnesium hydroxide, hydrotalcite, ethylenediaminetetraacetic acid (EDTA), sodium salt of EDTA, etc. (Chelating agent), spherical or amorphous silicon dioxide, calcium carbonate, talc and other typical finishes, fatty acid amides, waxes and other typical lubricants, azo-based, phthalocyanine-based, quinacridone-based, etc. Organic pigments and inorganic pigments represented by titanium oxide, carbon black, aluminum, mica, etc. are added in a total amount of 0.01 to 1.5 parts by weight with respect to 100 parts by weight of vinylidene chloride copolymer. About part may be added. Furthermore, 0.1 part by weight to 1.0 part by weight of a surfactant such as sorbitan fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene fatty acid ester or the like based on 100 parts by weight of the vinylidene chloride copolymer depending on the use. As a processing aid, 0.01 to 2.0 parts by weight of ethylene-vinyl acetate copolymer or fluorine-based processing aid may be added to 100 parts by weight of vinylidene chloride copolymer. These additives may be added before or after the polymerization of the vinylidene chloride copolymer.

  The mixing method of the additives and the like described above is not particularly limited, and a known method can be applied. For example, a heating / cooling mixing method using a high-speed Henschel mixer, a ribbon blender, or the like can be applied.

[Vinylidene chloride resin molded products]
A vinylidene chloride resin molded product can be produced by melt molding the vinylidene chloride resin composition. FIG. 1 is a schematic view showing an example of a production apparatus for producing a vinylidene chloride-based resin molded product by melt molding (extrusion molding, extrusion film formation) using the vinylidene chloride-based resin composition of the present embodiment. .

  The vinylidene chloride resin composition supplied from the hopper portion 102 of the extruder 101 is propelled by the screw 103, heated and kneaded to be melted, and extruded from the slit portion of the annular die 104 attached to the tip of the extruder 101. A cylindrical parison 105 is formed. The parison is quenched with the cold water in the cooling bath 106 and guided to the pinch rolls A and A '. Then, the cylindrical parison 105 is preheated in the hot water tank 107, and sent to C and C 'through the pinch roll groups B and B'. Here, the cylindrical parison 105 includes the pinch roll groups B and B ′ and C and C ′, the volume of air sealed in the cylinder, and the pinch rolls B and B ′ and C and C ′. Are stretched and oriented approximately 4 times in the circumferential direction and longitudinal direction of the cylinder. The stretched and oriented tubular film is folded into two flat sheets, wound up by a winding roll 108, and then peeled off one by one. Thereby, a film-like vinylidene chloride resin molded product is produced.

  The form of the vinylidene chloride-based resin molded product may be a film-shaped single-layer molded product, a sheet-shaped single-layer molded product, or a multilayer molded product including one or more layers corresponding to these. The thickness of the film, sheet, or layer is preferably 1 μm to 1000 μm, more preferably 5 μm to 500 μm, and still more preferably 8 μm to 200 μm. Industrial production is easy with a thickness of 1 μm or more, and production efficiency is improved with a thickness of 1000 μm or less.

  The vinylidene chloride resin molded product is laminated with metal foil such as paper, aluminum or various synthetic resin films such as polyethylene, polypropylene, polyester, polyamide, polyvinyl alcohol, polyvinyl chloride on the front surface and / or back surface. Good. In addition, the lamination method to a vinylidene chloride resin molded product can employ | adopt a well-known method suitably, and is not specifically limited. As a laminating method, for example, a dry laminating method, a wet laminating method, an extrusion laminating method, or the like can be applied.

  Further, the vinylidene chloride-based resin molded product may be one in which various synthetic resins such as polyethylene, polypropylene, polyester, polyamide, polyvinyl alcohol, and polyvinyl chloride are arranged on the front surface, back surface, and / or side surface. For example, such a composite can be obtained by co-extrusion of the above-mentioned vinylidene chloride resin composition and various synthetic resins.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to the following Example.

[Example 1]
Vinylidene chloride (hereinafter referred to as “VDC”)-methyl acrylate (hereinafter referred to as “MA”) copolymer (copolymerization ratio of VDC / MA = 95 wt% / 5 wt%, weight average) Glycidyl methacrylate (hereinafter referred to as “GMA”) / styrene (hereinafter referred to as “St”) / methyl methacrylate (hereinafter referred to as “St”) as a heat stabilizer (A) with respect to 100 parts by weight of molecular weight 80,000). 3) parts by weight of copolymer (GMA content = 30 wt%, weight average molecular weight 10,000), and α-tocopherol (hereinafter referred to as “VE”) as an antioxidant (B). And 0.1 parts by weight of the mixture was added and mixed to prepare a vinylidene chloride resin composition. Next, the obtained vinylidene chloride-based resin composition was formed by extrusion using the apparatus shown in FIG. 1 by an inflation method to produce a film (vinylidene chloride-based resin molded product) having a thickness of 15 μm.

[Example 2]
Except that 0.5 part by weight of GMA / St copolymer (GMA content = 50 wt%, weight average molecular weight 20,000) was added as the heat stabilizer (A), the same operation as in Example 1 was carried out, and the thickness A 15 μm film was prepared.

[Example 3]
A film having a thickness of 15 μm was prepared by performing the same operation as in Example 2 except that 3 parts by weight of the heat stabilizer (A) was added.

[Example 4]
Except for adding 5 parts by weight of the heat stabilizer (A), the same operation as in Example 2 was performed to produce a film having a thickness of 15 μm.

[Example 5]
Except that 3 parts by weight of GMA / stearyl methacrylate (hereinafter referred to as “SMA”) copolymer (GMA content = 75 wt%, weight average molecular weight 10,000) was added as a heat stabilizer (A). The same operation as in Example 1 was performed to produce a film having a thickness of 15 μm.

[Example 6]
A film having a thickness of 15 μm was prepared in the same manner as in Example 1 except that 3 parts by weight of GMA / MMA (GMA content = 50 wt%, weight average molecular weight 10,000) was added as a heat stabilizer (A). did.

[Example 7]
The same operation as in Example 3 was carried out except that 0.1 part by weight of VE and 0.1 part by weight of dibutylhydroxytoluene (hereinafter referred to as “BHT”) were added as the antioxidant (B). And a film having a thickness of 15 μm was produced.

[Example 8]
As an antioxidant (B), 0.1 part by weight of VE and triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (hereinafter referred to as “Irg245”) A film having a thickness of 15 μm was produced in the same manner as in Example 3 except that 0.1 part by weight of (denoted) was added.

[Example 9]
As an antioxidant (B), 0.005 part by weight of VE and triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (hereinafter referred to as “Irg245”) A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that 0.005 parts by weight of (denoted) was added.

[Example 10]
As an antioxidant (B), 0.03 parts by weight of VE and triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (hereinafter referred to as “Irg245”) A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that 0.03 part by weight of (denoted) was added.

[Example 11]
As an antioxidant (B), 0.3 part by weight of VE and triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (hereinafter referred to as “Irg245”) A film having a thickness of 15 μm was produced in the same manner as in Example 3 except that 0.3 part by weight of (denoted) was added.

[Example 12]
A film having a thickness of 15 μm was prepared in the same manner as in Example 3, except that 0.1 part by weight of stearic acid was added as the fatty acid (C) without adding the antioxidant (B).

[Example 13]
A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that 0.1 part by weight of palmitic acid was added as the fatty acid (C) without adding the antioxidant (B).

[Example 14]
A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that 0.1 part by weight of erucic acid was added as the fatty acid (C) without adding the antioxidant (B).

[Example 15]
A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that 0.1 part by weight of VE as an antioxidant (B) and 0.1 part by weight of stearic acid as a fatty acid (C) were added. Produced.

[Example 16]
A film having a thickness of 15 μm was prepared in the same manner as in Example 3 except that the heat stabilizer (A) was added before polymerizing the polyvinylidene chloride-methyl acrylate copolymer.

[Example 17]
VDC-vinyl chloride copolymer (hereinafter referred to as “VC”) (copolymerization ratio of VDC / VC = 91 wt% / 9 wt%, weight average molecular weight 125,000) Add 3 parts by weight of GMA / St copolymer (GMA content = 50 wt%, weight average molecular weight 20,000) as thermal stabilizer (A), 0.1 parts by weight of VE as antioxidant (B) And mixed to prepare a vinylidene chloride resin composition. Next, the obtained vinylidene chloride-based resin composition was formed by extrusion using the apparatus shown in FIG. 1 by an inflation method to produce a film having a thickness of 15 μm.

[Comparative Example 1]
A film having a thickness of 15 μm was produced in the same manner as in Example 1 except that the heat stabilizer (A) was not added.

[Comparative Example 2]
The same operation as in Example 1 was performed except that 6 parts by weight of a GMA / St copolymer (GMA content = 50 wt%, weight average molecular weight 20,000) was added as a heat stabilizer (A), and the thickness was 15 μm. A film was prepared.

[Comparative Example 3]
A film having a thickness of 15 μm was produced in the same manner as in Example 3 except that the antioxidant (B) was not added.

[Comparative Example 4]
A film having a thickness of 15 μm was prepared in the same manner as in Example 1 except that 3 parts by weight of GMA polymer (GMA content = 100% by weight, weight average molecular weight 12,000) was added as the heat stabilizer (A). Was made.

  The compositions of the vinylidene chloride resin compositions prepared in Examples and Comparative Examples are summarized in Table 1 below.

  The characteristics of the film having a thickness of 15 μm, which is a vinylidene chloride-based resin molded product produced in Examples and Comparative Examples, were evaluated by the following methods. The results are summarized in Table 2.

(1) Evaluation of carbon foreign matter When a thermally deteriorated product (carbide) generated by the resin staying in the extruder suddenly peels and flows out, it becomes a carbon foreign matter. If a large carbon foreign matter (black) flows into the molded product, it is necessary to cut the molded product once to remove the foreign matter generating part and to splice the molded product due to the quality problem of the product. Therefore, a thermally deteriorated material mixed in the molded product was detected using an image sensor type foreign matter inspection machine. As an evaluation sample, a film (molded product) having an area of 2000 m ² and a thickness of 15 μm was used, and the number of carbon foreign objects having a size of 2 mm square or more was counted and evaluated based on the following criteria.
A: The number of foreign matters is 0, and very stable continuous production is possible.
○: The number of foreign matters is 1 or more and less than 5, and stable continuous production is possible.
(Triangle | delta): The number of foreign materials is 5 or more and less than 10, and although productivity falls somewhat, continuous production is possible.
X: The number of foreign matters is 10 or more, and continuous production is impossible.

(2) Evaluation of continuous extrudability The thermal stability of the resin against the retention of the resin in the barrel or screw part in the extruder is evaluated. If a large amount of foreign matter flows out, it is necessary to temporarily stop the film formation, replace the resin with polyethylene or the like, and scrape the thermally deteriorated material in the extruder, leading to a decrease in production efficiency. Here, the length of the continuous extrusion time until fine heat-deteriorated foreign matters and discolored materials flow out continuously and in large quantities into the molded product was evaluated based on the following criteria.
A: Continuous extrusion time is 48 hours or more, and very stable continuous production is possible.
○: The continuous extrusion time is 24 hours or more and less than 48 hours, and stable continuous production is possible.
(Triangle | delta): Continuous extrusion time is 6 hours or more and less than 24 hours, but productivity falls somewhat, but continuous production is possible.
X: Continuous extrusion time is less than 6 hours, and continuous production is impossible.

(3) Evaluation of transparency Based on ASTM D-1003, the transparency of a film having a thickness of 15 μm was measured at 23 ° C. and 50% using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., model “NDH 5000”). Measurement was performed under the conditions of RH, and evaluation was performed based on the following criteria.
○: Less than 5% and good transparency.
Δ: 5% or more and less than 10%, which is slightly inferior in transparency but acceptable.
X: 10% or more and poor transparency.

Based on ASTM D-1003, the transparency of a film having a thickness of 15 μm that was heat-treated under the following retort conditions was 23 ° C. and 50% RH using a turbidimeter (Nippon Denshoku Industries Co., Ltd., model “NDH 5000”). The measurement was performed under the following conditions, and evaluation was performed based on the following criteria.
○: Less than 8% and good transparency.
Δ: It is 8% or more and less than 15%, and is slightly inferior in transparency, but is acceptable.
X: 15% or more and poor transparency.
(Retort conditions): The film was fixed to a metal frame, immersed in pressurized hot water at 120 ° C. for 20 minutes without being thermally contracted, and then dried at room temperature for 2 days.

(4) Evaluation of oxygen permeability (barrier property) The degree of deterioration of oxygen permeability (O ₂ TR) due to the addition of the heat stabilizer (A) and the antioxidant (B) is evaluated. Oxygen permeation of the film formed by extrusion without adding the heat stabilizer (A), the antioxidant (B) and / or the fatty acid (C) to the vinylidene chloride copolymer used for each evaluation The degree was defined as a standard value (standard O ₂ TR), and the degree of deterioration (deterioration rate) of the oxygen permeability of the evaluation film was calculated according to the following formula and evaluated based on the following criteria. The measurement of oxygen permeability of a film having a thickness of 15 μm was carried out under conditions of 23 ° C. and 65% RH using OX-TRAN (manufactured by MOCON, model 2/20).
[Oxygen permeability deterioration rate (%)] = ([Evaluation film O ₂ TR] − [Standard O ₂ TR]) / [Standard O ₂ TR] × 100
○: Less than 80% and good barrier properties.
(Triangle | delta): It is 80% or more and less than 100%, and the fall of barrier property is recognized, but it can be used.
X: 100% or more and deterioration of barrier properties.

The oxygen permeability of a 15 μm thick film heat-treated under the above retort conditions was measured in the same manner as described above, and the barrier properties after retort treatment were evaluated based on the following criteria.
○: Less than 80% and good barrier properties.
(Triangle | delta): It is 80% or more and less than 100%, and the fall of barrier property is recognized, but it can be used.
X: 100% or more and deterioration of barrier properties.

(5) Measurement of amount of monomer having residual glycidyl group 10 mL of acetone is added to 1 g of the heat stabilizer (A), followed by heat extraction at 50 ° C. for 1 hour to obtain an extract. This extract was analyzed by GC / MS (column: DB-WAX, 30 m × 0.25 mm × 0.25 μm), and the amount of the monomer having a glycidyl group in the heat stabilizer (A) was quantified. The amount of the monomer having a glycidyl group remaining in the vinylidene chloride-based resin composition depends on the amount of the monomer having a glycidyl group remaining in the heat stabilizer (A) and the addition amount of the heat stabilizer (A). Calculated from the following equation.
[Amount of monomer having glycidyl group remaining in vinylidene chloride-based resin composition (mg / kg)] = [Amount of monomer having glycidyl group remaining in heat stabilizer] × Addition amount / 100

  Acetone (10 mL) is added to 1 g of the molded product, and heat extraction is performed at 50 ° C. for 1 hour to obtain an extract. This extract was analyzed by GC / MS (column: DB-WAX, 30 m × 0.25 mm × 0.25 μm), and the amount of the monomer having a glycidyl group in the molded product was quantified.

  The vinylidene chloride-based resin molded product of the present invention is excellent in thermal stability during melt molding and has high productivity. Therefore, the vinylidene chloride-based resin molded product can be used widely and effectively in packaging materials, and in particular, transparency, barrier properties and hygiene. Therefore, it can be suitably used for packaging materials that require transparency such as pharmaceuticals and foods.

  DESCRIPTION OF SYMBOLS 101 ... Extruder, 102 ... Hopper part, 103 ... Screw, 104 ... Circular die, 105 ... Cylindrical parison, 106 ... Cooling tank, 107 ... Hot water tank, 108 ... Winding roll, A, A ', B, B' , C, C '... Pinch roll.

Claims (7)

A vinylidene chloride copolymer;
A heat stabilizer containing a copolymer of a monomer having a glycidyl group and a monomer having no glycidyl group;
Antioxidants and / or fatty acids;
Is a vinylidene chloride resin molded product formed from a vinylidene chloride resin composition containing
The vinylidene chloride-based resin composition includes 0.1 to 5 parts by weight of the thermal stabilizer with respect to 100 parts by weight of the vinylidene chloride-based copolymer,
The molded product, wherein the amount of the monomer having the glycidyl group remaining in the vinylidene chloride-based resin molded product is 4.0 mg / kg or less.   The molded article according to claim 1, wherein the copolymer is a copolymer of 30 to 75% by weight of a monomer having a glycidyl group and 25 to 70% by weight of a monomer having no glycidyl group.   The molded article according to claim 1 or 2, wherein the monomer having no glycidyl group contains at least one selected from the group consisting of styrene and (meth) acrylic acid esters.   The molded article according to any one of claims 1 to 3, wherein the antioxidant is at least one selected from the group consisting of phenolic antioxidants and hindered phenolic antioxidants.   The molded article according to any one of claims 1 to 4, wherein the antioxidant contains α-tocopherol.   The molded article according to any one of claims 1 to 5, wherein the fatty acid is at least one selected from the group consisting of stearic acid, palmitic acid and erucic acid.   The molded article according to any one of claims 1 to 6, comprising a vinylidene chloride resin composition in which the amount of the monomer having a glycidyl group remaining is 0.1 mg / kg or less.

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