JP4322667B2 - Vinylidene chloride copolymer particle composition - Google Patents

Abstract

A composition of vinylidene chloride copolymer particles which, when extruded into a film or sheet, is capable of being stably extruded evenly and which has improved thermal stability. The vinylidene chloride copolymer particles are characterized by having a weight−average particle diameter of 200 to 500 µm and having a content of particles having a particle diameter smaller than 150 µm of 3 wt.% or lower. The vinylidene chloride copolymer composition is characterized by being obtained by compounding the copolymer particles with an ethylene/vinyl acetate copolymer and an ester of an &agr;,ß−unsaturated carboxylic acid.

Description

  The present invention relates to a vinylidene chloride copolymer composition and a film and sheet using the same.

Since vinylidene chloride copolymers have excellent gas barrier properties such as water vapor and oxygen and oil resistance, they are particularly suitable for food packaging films. There are suspension polymerization methods and emulsion polymerization methods for producing vinylidene chloride copolymers used for food packaging films, but suspension polymerization methods are used because there are no problems such as residual emulsifiers. . The suspension polymerization method is a method of performing polymerization by adding a polymerization initiator after forming mixed dispersion oil droplets of vinylidene chloride and a polymerizable vinyl monomer by water in a water containing a dispersant.
When obtaining a film for food packaging, the vinylidene chloride copolymer obtained by suspension polymerization is stretched by a normal melt molding method or processed into a single-layer or multilayer film without stretching. Is done.

  Generally, the vinylidene chloride copolymer obtained by suspension polymerization is known to be in the form of particles in Japanese Patent Publication Nos. 55-18242 and 57-9575, but the particle size distribution and bulk specific gravity are known. Only a wide copolymer particle composition can be obtained. US Pat. No. 3,706,722 discloses a method of obtaining a vinylidene copolymer particle composition by polymerizing vinyl chloride and vinylidene chloride resin in combination of mass polymerization and suspension polymerization. However, this method cannot stably extrude the resin, and it is difficult to obtain a film having a uniform film thickness. That is, the amount of the copolymer filled in the barrel from the die varies due to variations in the shape and size of the vinylidene chloride copolymer, which affects the discharge amount of the extruder. This fluctuates the head pressure, and as a result, the film thickness of the extruded film becomes non-uniform. When a film with a non-uniform film thickness is subjected to high-frequency sealing to obtain a film package, the sealing strength does not become uniform, and the production yield tends to decrease. In order to solve this problem, it is necessary to stably supply a certain amount of the copolymer particle composition into the extruder. However, no technology has specifically addressed this issue.

On the other hand, the vinylidene chloride copolymer is easily pyrolyzed during the extrusion process, and the pyrolysis causes carbides to flow out or the resulting film to turn yellow. In order to improve the thermal stability, the following proposals have been made conventionally.
By adding a copolymer of ethylene and vinyl acetate (hereinafter abbreviated as EVA) to a vinylidene chloride copolymer, the thermal stability during extrusion is improved and the low-temperature properties of the resulting film are improved. As a method, JP-A-55-108442 (comprising about 5 to about 40% by weight of EVA containing a vinyl acetate content of about 5 to about 18% by weight and a melt flow of about 0.1 to about 1.0 dg / min. ), Japanese Patent Publication No. 3-503290 (containing about 0.01 to about 2% by weight of EVA having a vinyl acetate content of about 28%), Japanese Patent Publication No. 40-16141 (2% of EVA having a vinyl acetate content of 3 to 20%) JP-A-1-131268 (comprising EVA having a vinyl acetate content of about 3 to about 30% by weight), re-published patent WO 96/34050 (ethylene containing 65 to 85% by weight of EVA). 5-3 mass Blending). However, these methods did not provide sufficient thermal stability.

  On the other hand, as another method for improving extrusion processability, JP-A-53-16753 (comprising a styrene polymer or styrene-methyl methacrylate polymer containing styrene having a specific softening point and melt viscosity) ), Japanese Patent No. 2947931 (addition of at least 0.5 part by weight of methyl methacrylate-butyl acrylate-styrene terpolymer to vinylidene chloride-methyl acrylate copolymer), Japanese Patent Publication No. 3078663 (from butyl acrylate, butyl methacrylate and methyl methacrylate) Incorporated polymer), JP-A-6-234902 (incorporating up to about 4% by weight of acrylate copolymer), JP-A-8-208926 (incorporating acrylate / styrene copolymer), JP-A-7 -268162 Distribution (styrene component, compounding a styrene copolymer resin composed of butyl acrylate component and methyl methacrylate component) is.

  However, according to these methods, even if thermal stability is satisfied by blending various copolymers and additives, such as suitability for food packaging filling machines obtained from vinylidene chloride copolymers, gas barrier properties, etc. Characteristics are likely to deteriorate. On the other hand, when the molecular weight of the vinylidene chloride copolymer is lowered, the mechanical strength of the film is lowered. In addition, when the extrusion process is carried out continuously, the heat deteriorated material generated inside the extruder affects the film that can adhere to the screw and die, so the production is interrupted and the screw and die are washed. There is a need to do. Thereby, since the time spent for extrusion production is shortened, productivity will fall.

Japanese Patent Publication No.55-18242 Japanese Patent Publication No.57-9575 US Pat. No. 3,706,722 JP-A-55-108442 JP-T-3-503290 Japanese Patent Publication No. 40-16141 JP-A-1-131268 International Publication No. 96/34050 Pamphlet JP-A-53-16753 Japanese Patent No. 2947931 Japanese Patent No. 3078663 JP-A-6-234902 JP-A-8-208926 JP 7-268162 A

  The present invention provides a vinylidene chloride copolymer capable of producing a film excellent in extrusion stability and, as a result, excellent in film thickness uniformity, and vinylidene chloride resin composition excellent in thermal stability and extrusion stability. The purpose is to provide.

In order to solve the above problems, the present inventors have a specific particle size obtained from suspension polymerization, and a vinylidene chloride copolymer composition in which the amount of contained fine particles is a certain amount or less, and It has been found that a vinylidene chloride copolymer particle composition having a bulk specific gravity may be used. Furthermore, a composition obtained by blending this specific particle composition with an ethylene / vinyl acetate copolymer and a copolymer obtained from two or more monomers selected from monomers of α and β unsaturated carboxylic acid esters is used. As a result, it was found that stable extrudability was further improved, and the present invention was achieved. That is, the present invention is as follows.

1. The weight average particle diameter is in the range of 250 to 350 μm, the proportion of particles having a particle diameter of less than 150 μm is 3 wt% or less, and the bulk specific gravity is 0.80 g / cm ^{3 to} 1.0 g / cm ^3. A vinylidene chloride copolymer particle composition characterized by the above.
2. 1. A vinylidene chloride copolymer is obtained by copolymerization of one or more monomers selected from vinylidene chloride and a polymerizable vinyl monomer. The copolymer particle composition described in 1.
3. 1. The polymerizable vinyl monomer is at least one selected from vinyl chloride, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, acrylonitrile, and styrene. The copolymer particle composition described in 1.
4.1. ~ 3. A film or sheet obtained from the vinylidene chloride copolymer particle composition according to any one of the above.

5. Weight average particle diameter in the range of 250 to 350 [mu] m, the proportion of particles less than the particle size 150μm is equal to or less than 3 wt%, and a bulk specific gravity of ^at 0.80g / cm ³ ~1.0g / cm 3 Selected from 100 parts by mass of a certain vinylidene chloride copolymer particle composition (A), 0.05 to 2.95 parts by mass of an ethylene-vinyl acetate copolymer (B1), and monomers of α and β unsaturated carboxylic acid esters It is a composition consisting of 0.05 to 2.95 parts by mass of the copolymer (B2) composed of two or more types of monomers, and the total of the blended mass of (B1) and the blended mass of (B2) is A vinylidene chloride copolymer composition characterized by being 3 parts by mass or less.
6). 4. The ratio (Wa) of the vinyl acetate component in the ethylene-vinyl acetate copolymer (B1) is 10 to 30 wt%. The vinylidene chloride copolymer composition described in 1.
7). 4. The α, β unsaturated carboxylic acid ester monomer is at least one selected from butyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, and methyl methacrylate. Or 6. The copolymer composition described in 1.
8.5. ~ 7. A film or sheet obtained from the vinylidene chloride copolymer composition according to any one of the above.

  According to the present invention, it is possible to produce a film excellent in extrusion stability and as a result excellent in film thickness uniformity, and can provide a vinylidene chloride-based resin composition excellent in thermal stability and extrusion stability.

The vinylidene chloride copolymer in the present invention is obtained by copolymerizing a vinylidene chloride monomer and a vinyl monomer copolymerizable with the monomer.
Examples of vinyl monomers copolymerizable with vinylidene chloride monomers include vinyl esters such as vinyl chloride, vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, hydroxypropyl Α, β unsaturated carboxylic esters such as acrylate, phenyl acrylate, cyclohexyl acrylate, glycidyl acrylate and methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, glycidyl methacrylate; Olefins such as ethylene and propylene; Vinyl ethers such as lauryl vinyl ether, ethyl vinyl ether and other lauryl vinyl ethers and isobutyl vinyl ether; others, itaconic acid, maleic acid, maleic anhydride, acrylonitrile, methacrylonitrile, styrene, methylstyrene, α-methylstyrene, chlorostyrene, chloromethyl Examples include styrene. These polymerizable vinyl monomers may be used alone or as a mixture of two or more.
Among these, vinyl chloride, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, acrylonitrile, and styrene are preferable.

The vinylidene chloride copolymer particle composition of the present invention has a weight average particle diameter of 250 to 350 μm. When the particle diameter is within this range, the extrusion load becomes constant and stable extrusion processing is possible. The resulting film thickness can be made uniform. The particle size distribution can be measured by a Coulter Multisizer particle measuring device TA-II type manufactured by Nikka Kikai Co., Ltd.
Moreover, the mass ratio of particles less than 150 μm needs to be 3 mass% or less. If more fine particles are contained, the melt tension applied during the extrusion process is not constant, and the film thickness becomes non-uniform. More preferably, particles having a size of 150 μm or less are 2.5% by mass or less.

Further or Is specific gravity is preferably made of a viewpoint of stably supplying a vinylidene chloride copolymer particle composition at a constant amount of ^{0.80g / cm 3 ~1.0g / cm 3} . Preferably from ^{0.90g / cm 3 ~0.98g / cm 3} . Bulk specific gravity can be measured based on JIS K-6722.
Furthermore, preferable conditions of the particle composition are as follows: the weight average particle diameter is 250 to 350 μm, the weight ratio of fine particles less than 150 μm is 1.5 wt% or less, and the bulk specific gravity is 0.90 g / cm ^{3 to} 0.98 g / This is the case for cm ³ .

  The weight average molecular weight of the vinylidene chloride copolymer particle composition is preferably about 60,000 to 200,000, preferably 70,000 to 150,000. More preferably, it is 80,000 to 130,000. The above range is preferable from the viewpoint of thermal stability, suitability for packaging and filling machines, and gas barrier properties. Two or more kinds of vinylidene chloride copolymer particle compositions having different weight average molecular weights may be blended at an arbitrary ratio, and the weight average molecular weight of the composition may be within the above range. In addition, about the weight average molecular weight, it measured using the polystyrene conversion weight average molecular weight by gel permeation chromatography measurement.

There are the following methods for obtaining the vinylidene chloride polymer particle composition of the present invention.
First, the above-mentioned vinylidene chloride monomer and a monomer copolymerizable therewith are copolymerized. Examples of the polymerization initiator used for polymerization include diisopropyl peroxydicarbonate, dioctyl peroxydicarbonate, dilauryl peroxydicarbonate, dimyristyl peroxydicarbonate, dicetyl peroxydicarbonate, and ditertiary butyl. Peroxydicarbonate, di (ethoxyethyl) peroxydicarbonate, di (methoxyisopropyl) peroxydicarbonate, di (3methoxybutyl) peroxydicarbonate, di (3methoxy-3-methylbutyl) peroxydicarbonate, Di (butoxyethyl) peroxydicarbonate, di (2isopropoxyethyl) peroxydicarbonate, di (2ethylhexyl) peroxydicarbonate, di (2isopropoxyethyl) peroxydi Percarbonate-based initiators such as carbonate, dibenzylperoxydicarbonate, dicyclohexylperoxydicarbonate, ditertiarybutylcyclohexylperoxydicarbonate, etc .; tertiary butylperoxyneodecanate, tertiary hexylperoxyneodecanoate , Amyl peroxyneodecanate, tertiary octylperoxyneodecanate, α-cumylperoxyneodecanate, 1-cyclohexyl-1-methylethylperoxyneodecanate, tertiary butyl peroxypivalate, amylper Oxypivalate, Tertiary octyl peroxypivalate, Tertiary hexyl peroxypivalate, α-cumyl peroxypivalate, Perhexyl oxalate, Ditersi Primary butyl peroxy oxalate, acetyl cyclohexyl sulfonyl peroxide,

1.1.3.3. Perester initiators such as tetramethylbutylperoxyphenoxyacetate; diacyl peroxide initiators such as lauroyl peroxide, diisobutyl peroxide, 2ethylhexanoyl peroxide, 3.5.5 trimethylhexanoyl peroxide; t Di-t-alkyl peroxydiglycolates such as butyl hydroperoxide, di-t-butyl peroxide, benzoyl peroxide, di-isopropyl peroxy dicarbonate, t-butyl peroxyisobutyrate, t-hexyl peroxy diglycolate System initiator: 2.2′azobisisobutyronitrile, 2.2′azobis-2.4dimethylvaleronitrile, 2.2′azobis-4methoxy-2.4dimethylvaleronitrile, 4,4-azobis ( 4-shi Azo initiators such as nopentanoic acid) 2.2'-azobis (2-amidinopropane) hydrochloride, 2.2'-azobis (NN'-dimethyleneisobutylamidine) hydrochloride; potassium persulfate, ammonium persulfate Or a water-soluble peroxide such as an initiator obtained by adding a reducing agent such as amine or sodium bisulfite to these. In order to make the polymerization reaction rate uniform, two or more kinds of polymerization initiators having different 10-hour half lives may be used in combination. These polymerization initiators can be used as they are, or can be used as water emulsions or water suspensions.

100-7000 ppm is preferable with respect to the liquid mixture of a vinylidene chloride monomer and a vinyl-type monomer, and, as for the usage-amount of an initiator, More preferably, it is 500-5000 ppm. More preferably, it is 1000-3000 ppm.
Next, a vinylidene chloride copolymer is polymerized to obtain a particle composition.
As in the present invention, the suspension polymerization method is preferred in order to obtain a vinylidene chloride copolymer particle composition having a specific gravity in a specific range.
Suspending and dispersing agents include homopolymers such as polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, polymethyl vinyl ether, polyacrylamide, polyethyleneimine, poly (2-ethyl-2-oxazoline), maleic anhydride-vinyl acetate copolymer Synthetic polymers such as coalescence and various random copolymers, graft copolymers, block copolymers, macromonomers, etc .; water-soluble cellulose derivatives such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose; natural polymer substances such as starch and gelatin Etc. If necessary, an auxiliary stabilizer can be used in addition to the dispersion stabilizer. Examples of such auxiliary stabilizers include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and long-chain alcohols. Among these, methyl cellulose, hydroxypropyl cellulose, and hydroxypropoxymethyl cellulose are particularly preferable. The surface tension at 20 ° C. of a 0.2 wt% aqueous solution of these stabilizers is preferably 5 mN / m or more from the viewpoint of the particle diameter to be obtained, and preferably 60 mN / m or less from the viewpoint of polymerization progress.

The addition amount of the suspension dispersant is preferably 300 ppm or more with respect to the vinylidene chloride monomer from the viewpoint of suspension polymerization stability, and preferably 1000 ppm or less from the viewpoint of the particle diameter to be obtained. By setting it in such a range, suspension stability is obtained, and a resin composition having a weight average particle diameter of 250 to 350 μm and a reduced amount of fine particles having a particle diameter of less than 150 μm is efficiently produced. can do. The suspension dispersant may be added all at once or in divided portions, and the timing of addition is not limited.
Also, since the corrosion rate of the apparatus in the polymerization machine and in the subsequent process is increased, an alkaline substance is used for the purpose of adjusting the pH at the initial stage of polymerization or during the polymerization so that the slurry pH of the vinylidene chloride copolymer does not decrease too much. May be added to the minimum necessary.

In the suspension polymerization reaction of vinylidene chloride monomer, a vinylidene chloride monomer, water, and a suspension dispersant are charged into a polymerization machine, and almost all of the prescribed amount is charged and stirred to form vinylidene chloride monomer droplets. Then start.
In order to improve the progress of the polymerization, it is preferable to make the inside of the reactor an atmosphere of nitrogen, argon gas or the like. The polymerization temperature and polymerization time may be appropriately determined depending on the type and amount of vinylidene chloride and polymerizable vinyl monomer, the type and amount of polymerization initiator, and the type and amount of chain transfer agent. It is preferably 10 hours to 100 hours, more preferably 20 to 60 hours, still more preferably 25 to 50 hours.

The vinylidene chloride copolymer in the present invention includes a lubricant, a gelation improver, a pH adjuster, a chain transfer agent, an antistatic agent, a crosslinking agent, an antifoaming agent, a stabilizer, a filler, an antioxidant, and scale adhesion. Additives such as inhibitors may be added as appropriate. These can be added at the initial stage of polymerization, during polymerization, or after polymerization.
There is no restriction | limiting in particular in the stirrer of a polymerization device used for suspension polymerization, A baffle can also be used if desired. Examples of the stirrer include turbine blades, fan turbine blades, Faudler blades, and blue margin blades that are usually used for polymerization of vinyl chloride monomers. It is preferable to use it. Examples of the baffle include finger type, cylindrical type, D type and loop type.

In order to obtain vinylidene chloride copolymer particles having a specific weight average particle diameter of the present invention, the generated polymer particles settle while maintaining the balance between the decrease in interfacial tension due to the suspending agent and the stirring speed of the stirrer. In other words, it is necessary to complete the polymerization without sticking to the reactor or the stirring blade. Therefore, it is particularly important to control the mechanical stirring conditions. Specifically, the stirring is performed while the polymer particles are suspended while selecting the stirring speed and the number of rotations of stirring.
In general, the agitation speed is set to a high speed so that the polymer particles are sufficiently suspended in order to float the polymer particles. In this case, the polymer particles are subjected to the shearing force of the stirring blade, and the diameter of the polymer particles becomes small. Further, when the stirring speed is set to a low speed in order to increase the polymer particle diameter, the polymer starts to settle, and further, the agglomeration and fixation of the polymer occurs, and there is a possibility that the entire reactor is fixed. Therefore, conventionally, in order to proceed the polymerization stably, it is necessary to avoid the low speed rotation and select the high speed rotation as much as possible. As a result, the polymer particles become 200 μm or less.

In the present invention, a polymer particle size range excellent in stable extrudability was achieved by finding a stirring speed at which suspension polymerization proceeds stably in the vicinity of the limit for preventing sedimentation of the polymer.
For example, when a Faudler blade is used, it is preferable that the stirring speed represented by the following formula (1) is 0.7 m / sec or more because suspension polymerization is stably performed. The particle diameter of the polymer is preferably within an appropriate range. Specific conditions need to be changed according to the size of the stirring scale.
Stirring speed (m / sec) = n · π · d / 60 (1)
(N: stirring blade rotation speed (rpm), π: circumference, d: stirring blade span)
For example, when the stirring blade span is 400 mmφ, it is preferably about 1.3 to 4.2 m / sec at 60 to 200 rpm, and when it is 2000 mmφ, about 2.0 to 5.3 rpm is preferable at 20 to 50 rpm.

In order to further stabilize the extrusion processability, the vinylidene chloride-based resin particle composition of the present invention is further added to 100 parts by weight of the above-mentioned vinylidene chloride-based resin particle composition (A) and further an ethylene-vinyl acetate copolymer (B1). And a vinylidene chloride copolymer composition containing a specific amount of a copolymer (B2) comprising two or more monomers selected from monomers of α and β unsaturated carboxylic acid esters.
The ethylene content of the ethylene-vinyl acetate copolymer (B1) used in the present invention is in the range of 60 to 90 wt%, more preferably 70 to 90 wt%. In order to maintain the transparency of the formed film, the ethylene content is preferably 90 wt% or less, and the ethylene content is preferably 60 wt% or more in view of stability of the extruder motor load and the barrier property of the formed film.

The blending ratio of the copolymer (B1) is preferably in the range of 0.05 to 2.95 parts by mass, preferably 0.1 to 2 with respect to 100 parts by mass of the vinylidene chloride copolymer particle composition (A). 0.5 parts by mass, and more preferably 0.2 to 2.0 parts by mass. When the blending ratio of the copolymer (B1) is 2.95 parts by mass or less, the barrier property is also maintained while improving the thermal stability. Moreover, when the blending amount is 0.05 parts by mass or more, the effect of suppressing the outflow of the decomposition product becomes sufficient, and the thermal stability is also improved.
The melt index (MI) of the copolymer (B1) is preferably 3 to 180 g / min from the viewpoint of extrusion processability and gas barrier property. Preferably it is 5-160 g / min. The weight average molecular weight is preferably in the range of 30,000 to 150,000.

  The copolymer (B2) used in the present invention is a copolymer obtained from two or more types of monomers selected from monomers of α and β unsaturated carboxylic acid esters. The monomer for α, β unsaturated carboxylic acid ester is preferably an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, such as butyl acrylate, propyl acrylate, ethyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, hydroxy Examples thereof include ethyl acrylate, hydroxypropyl acrylate, phenyl acrylate, and cyclohexyl acrylate. Among these, butyl acrylate, ethyl acrylate, and methyl acrylate are more preferable in view of the balance between extrusion processability and gas barrier property.

Further, the alkyl methacrylate monomer is preferably an alkyl methacrylate having 1 to 8 carbon atoms of an alkyl group, such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, Phenyl methacrylate, cyclohexyl methacrylate, glycidyl methacrylate, and the like can be mentioned. Among these, methyl methacrylate, ethyl methacrylate, and butyl methacrylate are preferable from the balance of extrusion processability and gas barrier property.
The α, β unsaturated carboxylic acid ester monomer copolymer (B2) may be a copolymer obtained by any polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization. Of these, emulsion polymerization is preferred. Examples of the emulsion polymerization method include seed polymerization, graft polymerization, and multistage polymerization. In particular, a copolymer obtained by multistage polymerization is more preferable.

In multistage polymerization, after forming a polymer of a core phase, a polymerization method is performed in which a shell phase is sequentially formed by performing graft polymerization and stepwise polymerization on the core phase.
Among these, it is preferable to use a monomer having a glass transition temperature of 0 ° C. or less as a polymer, such as alkyl acrylate, from the viewpoint of film formation as the core phase.
Examples of the core phase include those obtained by polymerizing monomers or monomer mixtures of alkyl acrylates. For example, butyl acrylate, propyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, or the like is preferably used. In particular, butyl acrylate is preferred.

For the shell phase, monomers or monomer mixtures of alkyl methacrylate and alkyl acrylate are used. For example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, butyl acrylate, methyl acrylate, or the like is preferably used. Particularly preferred is methyl methacrylate.
The mass ratio of the core phase and the shell phase is polymerized in an arbitrary ratio in the range of 10 to 90 wt%: 90 to 10 wt%, preferably 30 to 70 wt%: 70 to 30 wt%, more preferably 50 to 70 wt%. %: 30 to 50 wt%.
When the ratio of the shell phase is within the above range, the dispersion of the copolymer in the film becomes uniform, and the sealing characteristics are maintained.

Further, the proportion of alkyl methacrylate in the shell phase is preferably 60 wt% or more, and more preferably 80 wt% or more. When the alkyl methacrylate is in the above range, it is compatible with the vinylidene chloride copolymer and a uniform dispersion of the copolymer can be obtained.
These copolymers (B2) preferably have a weight average molecular weight of 10,000 to 500,000, more preferably 30,000 to 300,000, and even more preferably 50,000 to 250,000.
The above range is preferable from the viewpoints of the meltability, thermal stability, uniform dispersibility, and seal strength of the vinylidene chloride copolymer composition.
The blending ratio of the copolymer (B2) is preferably in the range of 0.05 to 2.95 parts by mass with respect to 100 parts by mass of the vinylidene chloride copolymer particle composition (A) in terms of extrudability. Is in the range of 0.1 to 2.5 parts by mass, more preferably 0.2 to 2.0 parts by mass. When the blending ratio of the copolymer (B2) is 2.95 parts by mass or less, the barrier property can be maintained while the thermal stability is good. Further, when the blending amount is 0.05 parts by mass or more, the thermal stability is improved, for example, the effect of suppressing the outflow of decomposition products is sufficient.

The total of the blending mass of the copolymer (B1) and the blending mass of the copolymer (B2) is preferably 3 parts by mass or less. Preferably it is 0.2-2.5 mass parts, More preferably, it is the range of 0.5-2.0 mass parts. When the blending amount is 3 parts by mass or less, the balance between thermal stability and barrier property is particularly good. Moreover, when the blending amount is 0.1 parts by mass or more, the effect of suppressing the outflow of decomposition products is high, and the thermal stability is also high.
The vinylidene chloride copolymer particle composition obtained in the present invention further includes known plasticizers, heat stabilizers, processing aids, light stabilizers, pigments, lubricants, antioxidants, fillers, surfactants, etc. An additive may further be included.

  For example, a plasticizer such as dioctyl phthalate, acetyl tributyl citrate, dibutyl sebacate, dioctyl sebacate and diisobutyl adipate, or a polyester plasticizer comprising a saturated aliphatic dicarboxylic acid and a polyhydric alcohol, epoxidized soybean oil, epoxidized linseed Oil, epoxy stabilizers such as epoxidized octyl stearate, epoxy group-containing resins, amide derivatives of alkyl esters, waxes such as polyethylene oxide, paraffin wax, polyethylene wax, montan ester wax, fatty acid esters such as glycerin monoester, Fatty acid mono and bisamide lubricants: Nonionic surfactants such as sorbitan fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, etc. Agent, and the like.

The blending ratio of the additive is preferably about 0.01 to about 10 parts by mass, more preferably 0.05 to 6 parts by mass with respect to 100 parts by mass of the vinylidene chloride copolymer particle composition.
Vitamin E, citric acid and its salts, magnesium hydroxide, sodium pyrophosphate, sodium dihydrogen pyrophosphate, tetrasodium pyrophosphate, magnesium oxide and calcium hydroxyphosphate, ethylenediaminetetraacetic acid and its salts, butylhydroxy-anisole, Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2'methylene-bis- (4-methyl-6-tert-butyl-phenol), octadecyl-3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate, ethylenebis (oxyethylene) bis [3- (5-t-butyl-4-hydroxy-m-tolyl) propionate], 2-t -Butyl-6- (3-t-2-hydroxy-5- Phenol-based antioxidants such as tilbenzyl) -4-methylphenyl acrylate and 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate Agents, thiodipropionic acid; thiodipropionic acid alkyl esters such as dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate; pentaerythritol-tetrakis- (3-lauryl-thiopropio Thio) antioxidants of pentaerythritol alkylthioesters such as nate)), trisnonylphenyl phosphite, tris (mono and / or dinonylphenyl) phosphite, 4,4′-isopropylidenediphenol alkyl Phosphite, distea And phosphite antioxidants such as rilpentaerythritol diphosphite). Two or more kinds of antioxidants used in the present invention may be mixed and used.

The blending ratio of the heat stabilizers is preferably 0.0005 to 0.4 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the vinylidene chloride copolymer particle composition in terms of improving the thermal stability. Is 0.001 to 0.1 parts by mass.
Furthermore, various additives such as fillers such as silicon oxide and calcium carbonate may be added.
The additives (B1) and (B2) are usually mixed in the form of a powder before processing the vinylidene chloride resin, but may be added in a slurry state when the vinylidene chloride monomer is polymerized. Alternatively, polymerization may be carried out after previously adding to the vinylidene chloride monomer before polymerization.

The additive is adsorbed or absorbed by the vinylidene chloride copolymer during extrusion, and contributes to thermal stability. Additives other than plasticizers and heat stabilizers are preferably used as necessary. These mixing methods are not particularly limited, and conventional methods can be applied. For example, kneading with a two-roll machine, mixing with a blender such as a blade blender or ribbon blender, mixing with a Henschel high-speed mixer, and the like can be applied to any heating mixing method exceeding 60 ° C. or low temperature mixing method not exceeding 60 ° C. .
In addition, the vinylidene chloride copolymer particle composition (A) and the above-mentioned additive added as necessary are mixed in advance, and the copolymer (B1) and the copolymer (B2) are sequentially mixed. May be. In that case, it is preferable from the point of the homogeneity of the obtained vinylidene chloride copolymer containing resin composition that mixed resin temperature is about 80 degrees C or less, Preferably it mixes in the temperature range of 50 degreeC to room temperature.

When mixing at a temperature of 60 ° C. or less and when using a copolymer (B1) with a low ethylene content, the powder mixture of the mixed composition is prevented from blocking by a combination such as the addition of the wax, and the extrusion. It prevents biting of powder into the screw during processing, and can further improve fluctuations in motor load and extrusion amount.
When supplying the composition obtained from the vinylidene chloride copolymer composition and the additives (B1) and (B2) to the extruder as a raw material, the composition is continuously metered into the on-machine hopper device, It is preferable to use a feeder that supplies quantitatively. Examples of the feeder include a screw feeder, a circle feeder, an electromagnetic feeder, a weight feeder, and a positive displacement feeder. In this, the method of mixing using a weight type feeder is preferable. It is preferable because fluctuations in the motor load and extrusion amount during extrusion can be suppressed, steady supply to the extruder is possible, and stable extrusion is possible. In addition, the effect of suppressing the adhesion of the resin decomposition product at the die outlet is improved, and the coloring of the resin and the outflow of the decomposition product can be reduced.

  The vinylidene chloride copolymer composition of the present invention is melt extruded and stretched, or formed into a film, sheet or the like without stretching. As a molding method, for example, an inflation extrusion molding method using a circular die can be applied. A film obtained by orientation by biaxial stretching has heat shrinkability and can also be suitably used as a heat-resistant film applicable to so-called retort conditions of 20 minutes at 120 ° C. (pressure 0.245 MPa). Is. The draw ratio is preferably 2.0 to 4.5 times in the longitudinal direction and 3.0 to 5.0 times in the transverse direction. The film thickness is preferably 5 to 30 μm, more preferably 10 to 25 μm as a single film. It is also used as a double film depending on the application. The film obtained under such conditions exhibits the mechanical strength of the film at the time of packaging and fills the gas barrier property after packaging and is particularly suitable for food preservation applications.

Also, a multilayer film or sheet can be formed by coextrusion or lamination so that these vinylidene chloride copolymer compositions are further laminated on the gas barrier layer.
When extruding a vinylidene chloride copolymer particle composition, or a composition to which a processing aid is added, the composition is supplied to an extruder via a vacuum hopper, thereby providing stable extrudability and thermal stability. Will improve. The vacuum degree of the vacuum hopper is preferably −6.66 × 10 ⁻² MPa or less, more preferably in the range of −7.99 × 10 ⁻² to −10.1 × 10 ⁻² MPa. By supplying the composition to an extruder via a vacuum hopper set to such conditions, the extrusion processability and stretchability can be stably maintained. The film is stretched by a known method through a melt extruder connected to the lower part of the vacuum hopper, or is not stretched and is formed into a film, a sheet or the like.
Since the composition is stably supplied to the melt extruder by the above extrusion processing method, fluctuations in the load on the extruder motor and fluctuations in the extrusion amount can be kept small. This improves the thermal stability such as resin coloring, resin degradation product outflow suppression effect, and degradation product adhesion suppression effect at the die outlet. In addition, bubble bursting during inflation molding is further improved and reduced.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
In the examples and comparative examples, the following compounds and apparatuses were used.
・ Suspension dispersant
(M1) Methylcellulose
(2% aqueous solution viscosity 4000 mPa · s)
(M2) Hydroxypropyl methylcellulose
(2% aqueous solution viscosity 4000 mPa · s)
(M3) Hydroxypropyl methylcellulose
(2% aqueous solution viscosity 400 mPa · s)
・ Agitator blade (S1) Faudler blade

・ Ethylene-vinyl acetate copolymer (B1)
(B1-1): vinyl acetate content = 30 wt%, melt index = 6
(B1-2): vinyl acetate content = 25 wt%, melt index = 15
(B1-3): Vinyl acetate content = 20 wt%
Melt index = 160
(B1-4): vinyl acetate content = 10 wt%, melt index = 75
・ Α, β unsaturated carboxylic acid ester copolymer (B2)
(B2-1): BA / BMA / MMA = 14/16/70 wt%
Weight average molecular weight (Mw) 220,000
(B2-2): BA / MMA / MA = 40/55/5 wt%
Weight average molecular weight (Mw) 300,000
(B2-3): BA / MMA = 50/50 wt%
Weight average molecular weight (Mw) 50,000
* The above abbreviations indicate the following monomers.
BA: Butyl acrylate BMA: Butyl methacrylate MMA: Methyl methacrylate MA: Methyl acrylate

The characteristic measuring method and evaluation method in the present invention will be described.
1) Particle size distribution of vinylidene chloride copolymer particle composition The weight average particle size and the proportion of particles less than 150 μm are the particle size distribution using a Coulter Multisizer particle measuring device TA-II type (manufactured by Nikka Kisha Co., Ltd.). It measured by the measuring method.
Level value and evaluation of weight average particle size
Within the range of 250 to 350 μm: ◎
What becomes less than 250 μm: ×
Level value of the proportion of vinylidene chloride copolymer particles of less than 150 μm, evaluation 0 to 1.5 wt% or less: ◎
Those within the range of 1.5 wt% to 3 wt% or less: ○
Over 3wt%: ×

2) Bulk specific gravity Measured according to JIS K-6722.
(Powder tester PT-R type (powder measuring device manufactured by Hosokawa Micron))
The following judgment was performed by the value of bulk specific gravity.
0.9 to 1.0 g / cm ³ : ◎
0.8 to 0.9 g / cm ³ : ○
Less than 0.8 g / cm ³ : ×
3) Weight average molecular weight The weight average molecular weight of the polymer particle composition was measured by gel permeation chromatography (GPC) as follows.
Measuring apparatus: Tosoh Corporation gel permeation chromatograph HLC-8020
Column: TSKgel Super HM-H (Tosoh Corporation) 7.8 mm × 30 cm × 2
Eluent: THF, flow rate: 1 ml / min, temperature: 40 ° C., detection: RI

4) Stable extrudability: Fluctuation rate of supply rate of vinylidene chloride copolymer particle composition About 50 kg of vinylidene chloride copolymer particle composition was used, and the supply amount was set to 100 kg / hr with a screw feeder. The supply amount in a fixed time within a range of 10 to 20 minutes was measured (n = 5), and a simple average value and a standard deviation were obtained.
The fluctuation rate of the supply speed was obtained by the following formula (2) and used as a criterion for determining fluidity.
Here, Phytron SK-S (manufactured by Hosokawa Micron) was used as the screw type feeder.
Fluctuation rate of supply speed (%) = (standard deviation / simple average value) × 100 (2)
In addition, the liquidity was judged as follows based on this rate of change.
0% to 5%: ◎ (No problem in processability)
Exceeding 5%: × (Inferior processability and supply unevenness)

5) Film thickness uniformity The average film thickness and standard deviation of the prepared film at a length of about 300 m were measured, and the fluctuation rate of the film thickness was determined by the following formula (3), which was used as a criterion for extrudability. .
Fluctuation rate of film thickness (σ) (%) = (standard deviation / average film thickness) × 100 (3)
0% to 2%: ◎ (No problem in extrusion processability)
Exceeding 2%: × (Inferior extrudability, occurrence of film thickness unevenness)
6) Decomposition product outflow Decomposition product having a length of about 1 mm or more contained in the film was detected by visual observation.
Represents less than 10 per 1500 m: ◎
Represents less than 10-15 per 1500 m: ○
Represents 15 or more per 1500 m: ×

7) Suitability for packaging and filling machine Double slit slit into an automatic filling and ligating machine (Asahi Kasei ADP Food Packaging and Filling Machine) that integrates a film supply unit, high-frequency seal unit, automatic filling unit, and ligating unit so that the folding width is 40 mm. A package was obtained by applying a film, filling a cylindrical film center-sealed by high frequency sealing with water as a filler, and clipping both ends with metal wires. The state of the seal part at that time and the spark generation state of the seal electrode were observed.
・ Operating at a sealing speed of 30 m / min, and no trouble or sparks due to sealing will be observed for 60 minutes. : ◎
-The part where the film was partially thin and the seal wire was too melted occurred once or twice in 60 minutes. : ○
・ Troubles caused by seals and spark sparks occurred more than once or twice in 60 minutes. : ×

8) Yellowing degree of film The yellowing of the film was visually observed.
The yellowing of the film is not noticeable. : ◎
Represents an intermediate coloring degree between x and ◎. : ○
The degree of yellowing of the film is strong. : ×
9) Oxygen gas permeability: Measured at 30 ° C. and 100% relative humidity using an oxygen gas permeability measuring device (Ox-tran 2/20 manufactured by Modern Control). The unit is cm ³ / m ² / day / atm, and measurement was performed with a double film.
25 or less: ◎
25-30: ○
30 or more: ×
10) <Comprehensive evaluation>
A: Satisfies all evaluation items as A.
○: Satisfies each evaluation item, but contains some ○.
×: Inferior in characteristics.

[Example 1]
Deionized water and a suspension dispersant (M1) were added and dissolved in a reactor (internal volume 300 liters) equipped with a Faudler blade (span diameter 400 mm), finger baffle, thermometer and nitrogen gas introduction tube. 100 parts by mass of the suspension was adjusted (the concentration of the suspension dispersant was 500 ppm).
Next, 80 parts by mass of vinylidene chloride, 20 parts by mass of vinyl chloride, 0.15 parts by mass of initiator diisopropyl peroxydicarbonate and 2 parts of epoxidized linseed oil were added, and the stirring speed was 1.4 m / sec. To 45 ° C. to initiate polymerization. After the reaction was continued for about 10 hours, the temperature was raised to 55 ° C. in about 1 hour, the stirring speed was 1.2 times the initial speed (1.68 m / sec), and the polymerization was continued for another 15 hours. After completion of the reaction, the separated vinylidene chloride copolymer particle composition had a weight average particle diameter of 260 μm and a mass ratio of the particle diameter of less than 150 μm was 2.2 wt%. The bulk specific gravity was 0.90 g / cm ³ .
When the copolymer particle composition was dissolved in tetrahydrofuran and the molecular weight in terms of polystyrene was measured by gel permeation chromatography, the weight average molecular weight was 120,000. (Vinylidene chloride copolymer particle composition (A-1))
The evaluation results of the properties of the vinylidene chloride copolymer particle composition are shown in Table 1.

[Comparative Example 1]
Polymerization similar to that of Example 1 was performed except that the concentration of the suspension dispersant was 300 ppm and the stirring speed was 4.5 m / sec. The weight average molecular weight was 123,000. (Vinylidene chloride copolymer particle composition (A-6))
The results are shown in Table 3.

[Example 2]
Polymerization similar to that of Example 1 was performed except that the concentration of the suspension dispersant was 300 ppm and the stirring speed was 1.2 m / sec.
The weight average molecular weight was 116,000. (Vinylidene chloride copolymer particle composition (A-2))
The results are shown in Table 1.

[Comparative Example 2]
The same polymerization as in Example 1 was performed except that the concentration of the suspension dispersant was 1000 ppm and the stirring speed was 0.6 m / sec.
The weight average molecular weight was 120,000. (Vinylidene chloride copolymer particle composition (A-7))
The results are shown in Table 3.

[Example 3]
Polymerization similar to that of Example 1 was performed except that the concentration of the suspension dispersant was 300 ppm and the stirring speed was 1.0 m / sec. The weight average molecular weight was 115,000. (Vinylidene chloride copolymer particle composition (A-3))
The results are shown in Table 1.

[Example 4]
Polymerization was carried out in the same manner as in Example 1 except that the suspension dispersant (M2) was used, the concentration was 500 ppm, and the stirring speed was 1.2 m / sec. The weight average molecular weight was 118,000. (Vinylidene chloride copolymer particle composition (A-4))
The results are shown in Table 1.

[Comparative Example 3]
The same polymerization as in Example 1 was performed except that the suspension dispersant was (M2), the concentration was 1000 ppm, and the stirring speed was 0.6 m / sec. The weight average molecular weight was 121,000. (Vinylidene chloride copolymer particle composition (A-8))
The results are shown in Table 3.

[Example 5]
The same polymerization as in Example 1 was performed except that the suspension dispersant (M3) was used, the concentration was 1000 ppm, and the stirring speed was 1.0 m / sec. The weight average molecular weight was 121,000. (Vinylidene chloride copolymer particle composition (A-5))
The results are shown in Table 1.

[Example 6]
To 100 parts by mass of the vinylidene chloride copolymer particle composition (A-1) obtained in Example 1, 3 parts by mass of dibutyl sebacate as an additive, 1 part by mass of an antioxidant, a lubricant, and a red pigment were added. A vinylidene chloride copolymer particle composition was obtained.
Next, it is put into an extruder with a diameter of 40 mm, the vacuum pressure of the vacuum hopper is set to about −9.06 × 10 ⁻² MPa, the product is extruded in an annular shape, rapidly cooled in a cooling bath at 10 ° C., and then a hot water bath at 20 ° C. Pass through. Further, air was press-fitted between films sandwiched between two sets of pinch rolls having different rotational surface speeds, and the film was expanded by 2.8 times in the longitudinal direction and 3.7 times in the width direction. The obtained film was 100 m long and the thickness was 20 μm. The prepared film thickness and the variation rate (σ) of the film thickness were measured. The results are shown in Table 2.

[Example 7]
Using the vinylidene chloride copolymer particle composition (A-2) obtained in Example 2, a film was produced in the same manner as in Example 6 except that the degree of vacuum was −7.9 × 10 ⁻² MPa. The results are shown in Table 2.

[Example 8]
Using the vinylidene chloride copolymer particle composition (A-3) obtained in Example 3, a film was produced in the same manner as in Example 6 except that the degree of vacuum was −7.9 × 10 ⁻² MPa. The results are shown in Table 2.

[Example 9]
Using the vinylidene chloride copolymer particle composition (A-4) obtained in Example 4, a film was produced in the same manner as in Example 6 except that the degree of vacuum was −7.99 × 10 ⁻² MPa. The results are shown in Table 2.

[Example 10]
A film was produced in the same manner as in Example 6 except that the degree of vacuum was −6.66 × 10 ⁻² MPa using the vinylidene chloride copolymer particle composition (A-5) obtained in Example 5. The results are shown in Table 2.

[Example 11]
A film was produced in the same manner as in Example 6 except that a vacuum hopper was not used. The results are shown in Table 2.

[Comparative Example 4]
A film was produced in the same manner as in Example 6 using the vinylidene chloride copolymer particle composition (A-6) obtained in Comparative Example 1. The results are shown in Table 4.

[Comparative Example 5]
A film was produced in the same manner as in Example 6 using the vinylidene chloride copolymer particle composition (A-7) obtained in Comparative Example 2. The results are shown in Table 4.

[Comparative Example 6]
Using the vinylidene chloride copolymer particle composition (A-8) obtained in Comparative Example 3, a film was produced in the same manner as in Example 6 except that the degree of vacuum was −7.99 × 10 ⁻² MPa. The results are shown in Table 4.

[Comparative Example 7]
A film was produced in the same manner as in Comparative Example 4 except that a vacuum hopper was not used. The results are shown in Table 4.

[Example 12]
With respect to 100 parts by mass of the vinylidene chloride copolymer particle composition (A-1) obtained in Example 1, 0.3 part by mass of ethylene-vinyl acetate copolymer (B1-1), α and β unsaturated. After compounding 0.3 parts by weight of the carboxylic acid ester copolymer (B2-1), 3.5 parts by weight in total of epoxidized linseed oil and dibutyl sebacate as additives, further antioxidant, lubricant, red A total of 1.5 parts by mass of the pigment was added and mixed at a temperature of 50 ° C. to obtain a vinylidene chloride copolymer composition.
Next, with a 40 mm diameter extruder, the vacuum pressure of the vacuum hopper was about −9.06 × 10 ⁻² (MPa) and extruded in an annular shape, and then rapidly cooled in a 10 ° C. cooling bath, and then a 20 ° C. hot water bath was placed. The film was passed through and inflated by press-fitting air between two sets of pinch rolls having different rotational surface speeds, and stretched and oriented 2.8 times in the longitudinal direction and 3.7 times in the width direction. The obtained film had a length of 100 m and a single thickness of 20 μm. The variation rate (σ) of the film thickness of the produced film was measured. The results are shown in Table 5.

[Example 13]
The addition amount of ethylene-vinyl acetate copolymer (B1-2) was 0.5 parts by mass, and (B2-2) was added as an α, β-unsaturated carboxylic acid ester copolymer by 0.5 parts by mass. A film was produced in the same manner as in Example 12. The results are shown in Table 5.

[Example 14]
Add 1.0 parts by mass of ethylene-vinyl acetate copolymer (B1-1), 0.3 parts by mass of (B2-2) as α, β unsaturated carboxylic acid ester copolymer, and then add vacuum hopper A film was produced in the same manner as in Example 12 except that the vacuum pressure was about −7.99 × 10 ⁻² (MPa). The results are shown in Table 5.

[Example 15]
Other than adding 1.5 parts by mass of (B1-3) as an ethylene-vinyl acetate copolymer and adding 0.1 parts by mass of the α, β-unsaturated carboxylic acid ester copolymer (B2-1). Produced a film in the same manner as in Example 12.
The results are shown in Table 5.

[Example 16]
Implemented except that 1.0 part by mass of (B1-3) was added as an ethylene-vinyl acetate copolymer and 0.5 part by mass of (B2-2) was added as an α, β unsaturated carboxylic acid ester copolymer. A film was produced as in Example 12. The results are shown in Table 5.

[Example 17]
Deionized water and a suspension dispersant (M1) were added and dissolved in a reactor (internal volume 300 liters) equipped with a Faudler blade (span diameter 400 mm), finger baffle, thermometer and nitrogen gas introduction tube. 100 parts by mass of the suspension was adjusted (the concentration of the suspension dispersant was 500 ppm).
Next, 80 parts by mass of vinylidene chloride, 20 parts by mass of vinyl chloride, 0.15 parts by mass of initiator diisopropyl peroxydicarbonate and 2 parts of epoxidized linseed oil were added, and the stirring speed was 1.4 m / sec. To 45 ° C. to initiate polymerization. After the reaction was continued for about 10 hours, the temperature was raised to 60 ° C. in about 1 hour, the stirring speed was 1.2 times the initial speed (1.68 m / sec), and the polymerization was further continued for 15 hours. After completion of the reaction, the separated vinylidene chloride copolymer particles had a weight average particle size of 260 μm and a mass ratio of less than 150 μm was 2.3 wt%. The bulk specific gravity was 0.91 g / cm ³ .

When the copolymer particles were dissolved in tetrahydrofuran and the molecular weight in terms of polystyrene was measured by gel permeation chromatography, the weight average molecular weight was 100,000. (Vinylidene chloride copolymer particle composition (A-9))
100 parts by mass of the vinylidene chloride copolymer particle composition (A-9), 0.2 parts by mass of an ethylene-vinyl acetate copolymer (B1-4), an α, β unsaturated carboxylic acid ester copolymer (B2 -3) A film was produced in the same manner as in Example 12 except that the amount was 0.5 parts by mass. The results are shown in Table 6.

[Example 18]
The same as Example 17 except that 1.5 parts by mass of ethylene-vinyl acetate copolymer (B1-1) and 0.05 parts by mass of (B2-3) α, β-unsaturated carboxylic acid ester copolymer were added. Thus, a film was produced. The results are shown in Table 6.

[Example 19]
In Example 18, a film was produced in the same manner except that a vacuum hopper was not used. The results are shown in Table 6.

[Example 20]
Deionized water and a suspension dispersant (M1) were added and dissolved in a reactor (internal volume 300 liters) equipped with a Faudler blade (span diameter 400 mm), finger baffle, thermometer and nitrogen gas introduction tube. 100 parts by mass of the suspension was adjusted (the concentration of the suspension dispersant was 500 ppm).
Next, 90 parts by weight of vinylidene chloride, 10 parts by weight of vinyl chloride, 0.15 parts by weight of initiator diisopropyl peroxydicarbonate, and 2 parts of epoxidized linseed oil were added, and the stirring speed was 1.4 m / sec. To 45 ° C. to initiate polymerization. After the reaction was continued for about 10 hours, the temperature was raised to 55 ° C. in about 1 hour, the stirring speed was 1.2 times the initial speed (1.68 m / sec), and the polymerization was further continued for 10 hours. After completion of the reaction, the separated vinylidene chloride copolymer particles had a weight average particle size of 260 μm and a mass ratio of less than 150 μm was 2.0 wt%. The bulk specific gravity was 0.92 g / cm ³ .

The copolymer particles were dissolved in tetrahydrofuran and the molecular weight in terms of polystyrene was measured by gel permeation chromatography. The weight average molecular weight was 90,000. (Vinylidene chloride copolymer particles (A-10))
To 10 parts by mass of the obtained vinylidene chloride copolymer particle composition (A-10), 90 parts by mass of vinylidene chloride copolymer particle composition (A-1), ethylene-vinyl acetate copolymer (B1- 1) 0.3 parts by mass, α, β Unsaturated carboxylic acid ester copolymer (B2-1) A film was produced in the same manner as in Example 12 except that 0.3 parts by mass was added. The results are shown in Table 6.

[Comparative Example 8]
Film in the same manner as in Example 12 except that 3.3 parts by mass of ethylene-vinyl acetate copolymer (B1-1) was added and α and β unsaturated carboxylic acid ester (B2) was not added. Manufactured. The results are shown in Table 7.

[Comparative Example 9]
A film was prepared in the same manner as in Example 12 except that 3.3 parts by mass of α, β unsaturated carboxylic acid ester (B2-1) was added and ethylene-vinyl acetate copolymer (B1) was not added. Manufactured. The results are shown in Table 7.

[Comparative Example 10]
Example 12 was repeated except that 1.5 parts by mass of ethylene-vinyl acetate copolymer (B1-4) and 2.0 parts by mass of α, β-unsaturated carboxylic acid ester (B2-1) were blended. A film was produced. The results are shown in Table 7.

  Since the vinylidene chloride copolymer particle composition of the present invention can be stably extruded when melt-molded into a film or sheet, a film or sheet having excellent film thickness uniformity can be obtained. Furthermore, by making this copolymer particle composition a composition comprising an ethylene-vinyl acetate copolymer and a copolymer comprising two or more monomers selected from monomers of α and β unsaturated carboxylic esters. In the melt molding, the resin degradation product is prevented from flowing out, the adhesion of the resin degradation product at the die outlet is suppressed, and a film and a sheet excellent in suitability for packing and filling machines and gas barrier properties can be obtained. Moreover, the extrusion property can be improved by extruding the composition via a vacuum hopper.

Claims (8)

The weight average particle diameter is in the range of 250 to 350 μm, the proportion of particles having a particle diameter of less than 150 μm is 3 wt% or less, and the bulk specific gravity is 0.80 g / cm ^{3 to} 1.0 g / cm ^3. A vinylidene chloride copolymer particle composition characterized by the above.   The copolymer particle composition according to claim 1, wherein the vinylidene chloride copolymer is obtained by copolymerization of one or more monomers selected from vinylidene chloride and a polymerizable vinyl monomer.   The copolymer particle composition according to claim 2, wherein the polymerizable vinyl monomer is at least one selected from vinyl chloride, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, acrylonitrile, and styrene.   A film or sheet obtained from the vinylidene chloride copolymer particle composition according to any one of claims 1 to 3. Weight average particle diameter in the range of 250 to 350 [mu] m, the proportion of particles less than the particle size 150μm is equal to or less than 3 wt%, and a bulk specific gravity of ^at 0.80g / cm ³ ~1.0g / cm 3 Selected from 100 parts by mass of a certain vinylidene chloride copolymer particle composition (A), 0.05 to 2.95 parts by mass of an ethylene-vinyl acetate copolymer (B1), and monomers of α and β unsaturated carboxylic acid esters It is a composition consisting of 0.05 to 2.95 parts by mass of the copolymer (B2) composed of two or more types of monomers, and the total of the blended mass of (B1) and the blended mass of (B2) is A vinylidene chloride copolymer composition characterized by being 3 parts by mass or less.   The vinylidene chloride copolymer composition according to claim 5, wherein the proportion (Wa) of the vinyl acetate component in the ethylene-vinyl acetate copolymer (B1) is 10 to 30 wt%.   The copolymer composition according to claim 5 or 6, wherein the monomer of the α, β unsaturated carboxylic acid ester is at least one selected from butyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, and methyl methacrylate.   A film or sheet obtained from the vinylidene chloride copolymer composition according to any one of claims 5 to 7.