JP2018177890A - Vinylidene chloride-based copolymer resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolute thickness deviation by reducing melt viscosity to a level that no surface dot is generated even when processed to a tube or a thin film, without reducing gas barrier property in a resin composition containing a vinylidene chloride-based copolymer.SOLUTION: There is provided a vinylidene chloride-based copolymer resin composition which contains a vinylidene chloride-based copolymer containing vinylidene chloride and other monomer copolymerizable with the vinylidene chloride as monomer components and having weight average molecular weight of 50,000 to 200,000, and an acrylic copolymer containing methyl methacrylate, and butyl acrylate as monomer components, has melt viscosity at 175°C and shear rate of 100 (1/s) of 800 to 2300 (Pa s), contains no plasticizer nor stabilizer or both with total content of 8 mass% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin composition containing a vinylidene chloride copolymer, and in particular, a vinylidene chloride copolymer containing a low melt viscosity and excellent processability, and maintaining the gas barrier properties of the vinylidene chloride copolymer. It relates to a resin composition.

Since vinylidene chloride copolymers and resin compositions containing the same have gas barrier properties, they are used in various applications.
However, the vinylidene chloride copolymer has poor thermal stability because the melting temperature and the decomposition temperature are close. Therefore, during extrusion processing, extrusion is performed without performing sufficient kneading to shorten the time from melting to extrusion in order to prevent thermal deterioration, and therefore resin amount unevenness occurs in the flow direction and uneven thickness occurs. There's a problem.
Further, since the vinylidene chloride copolymer has a high melt viscosity, when it is intended to be extruded into a thin film or tube, flow spots occur in the flow path of the die, and as a result, the surface roughness decreases and the thickness There is also a problem that accuracy and transparency can not be ensured.

In general, as means for eliminating uneven thickness, it is known to reduce the extrusion speed or to lower the melt viscosity.
In this respect, reducing the extrusion rate leads to a decrease in productivity, and in the case of a vinylidene chloride copolymer, it also promotes thermal degradation.
On the other hand, lowering the melt viscosity leads not only to the elimination of uneven thickness, but also to the improvement of the surface roughness, thickness accuracy and the like described above. Therefore, it is preferable to lower the melt viscosity of the vinylidene chloride copolymer.

As a method of lowering the melt viscosity, it is conceivable to raise the processing temperature, but in the case of a vinylidene chloride copolymer, the progress of thermal deterioration becomes remarkable, and therefore this method can not be adopted.
Generally, in order to lower the melt viscosity of the resin, it is practiced to add a processing aid such as a plasticizer, but in the case of a vinylidene chloride copolymer, the effect of lowering the melt viscosity is the addition of the plasticizer. In addition, there is a problem that the gas barrier property which is the characteristic is impaired.

  Patent Document 1 discloses blending of a vinylidene chloride-methyl acrylate copolymer with an acrylic copolymer as a processing aid to improve thermal stability. However, in this technology, the melt viscosity and uneven thickness of the resin blend have not been studied.

Patent No. 2949731

  In view of the problems as described above, the present invention is a resin composition containing a vinylidene chloride copolymer, to such an extent that surface unevenness does not occur even when processed into a tube or a thin film without reducing the gas barrier properties. The problem is to lower the melt viscosity to eliminate uneven thickness.

As a result of intensive studies to solve the above-mentioned problems, the present inventor selects gas phase characteristic as vinylidene chloride-based copolymer and then adds specific acrylic-based copolymer to obtain gas barrier property. The inventors have found that the melt viscosity can be sufficiently lowered without loss, and the present invention has been completed using such knowledge.
Acrylic copolymers are generally used to increase the melt viscosity of vinyl chloride-based (co) polymers and promote gelation, but this is not the case when used for vinylidene chloride-based copolymers. It was unexpected that it had the effect of lowering the melt viscosity.

That is, the present invention is as follows.
[1] A vinylidene chloride copolymer having a weight average molecular weight of 50,000 to 200,000, comprising vinylidene chloride and another monomer copolymerizable with vinylidene chloride as a monomer component,
Methyl methacrylate and an acrylic copolymer containing butyl acrylate as a monomer component,
The melt viscosity at a shear rate of 100 (1 / s) is from 800 to 2300 (Pa · s) at 175 ° C.,
No plasticizer and stabilizer, or the total content of both is 8% by mass or less
Vinylidene chloride copolymer resin composition.
[2] The vinylidene chloride-based copolymer resin composition according to [1], wherein the weight average molecular weight of the acrylic copolymer is 80,000 to 200,000.
[3] The vinylidene chloride-based copolymer resin composition according to [1] or [2], wherein the vinylidene chloride-based copolymer contains 70% by mass or more of vinylidene chloride as a monomer component.
[4] The O ₂ TR value (oxygen permeability) of a composition having the same composition as the vinylidene chloride copolymer resin composition except that the acrylic copolymer is excluded is A, and the vinylidene chloride copolymer The vinylidene chloride-based copolymer resin composition according to any one of [1] to [3], wherein B / A is 1.5 or less when the O ₂ TR value of the polymer resin composition is B. .

  According to the present invention, a vinylidene chloride copolymer-containing resin composition excellent in extrusion processability and transparency can be provided without impairing the gas barrier properties.

It is the schematic of the film forming apparatus used when evaluating the film forming property of the resin composition in an Example.

  Hereinafter, the mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in more detail, but the present invention is not limited to this, and various modifications can be made within the scope of the present invention. Variations are possible.

1. Vinylidene chloride-based copolymer The vinylidene chloride-based copolymer resin composition of the present embodiment is a vinylidene chloride-based copolymer containing vinylidene chloride and another monomer copolymerizable with vinylidene chloride as a monomer component. Including union. The vinylidene chloride-based copolymer has high thermal stability compared to the case of vinylidene chloride homopolymer, and the effect of lowering the melt viscosity when combined with the acrylic copolymer of the present embodiment is remarkable. can get.

There is no limitation on other monomers copolymerizable with vinylidene chloride, but the solubility parameter (SP value) of the homopolymer is 9.0 to 11.0 (cal / cm ³ ) ^1/2 If there is, the difference with the SP value of vinylidene chloride is small, and the transparency of the vinylidene chloride copolymer itself is increased, which is preferable. The SP value is more preferably 9.0 to 10.0 (cal / cm ³ ) ^1/2 .
Here, the solubility parameter (SP value) means the amount defined by the following equation, where the cohesive energy density is ΔE (cal / mol) and the molecular volume is V (cm ³ / mol) .
SP value ((cal / cm ³ ) ^1/2 ) = (ΔE / V) ^1/2
As a specific method of determining the SP value, for example, the method of Fedors is known. In addition, for representative monomers, the SP value is “A Method for Estimating Both the Solubility Parameters and Molar Volumes of Liquids, POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, vol. 14, Issue 2, p. 147- No. 154, and these can also be used in this embodiment.

In the present embodiment, preferable specific examples of other monomers copolymerizable with vinylidene chloride include, for example, vinyl chloride and methyl acrylate because the difference between the decomposition temperature and the melting point of the copolymer becomes relatively large. Preferably mentioned.
Other specific examples include acrylic esters such as butyl acrylate, methacrylic esters such as methyl methacrylate and butyl methacrylate, acronitrile, isobutylene, vinyl acetate, etc. I will not.
One of these other monomers copolymerizable with vinylidene chloride may be contained (two-component copolymer), or two or more types may be contained (three or more comonomers) Polymer).

Among these, when vinyl chloride is used as another monomer copolymerizable with vinylidene chloride, the molecular weight distribution of the vinylidene chloride copolymer tends to be broad, and the melt tension is high. Film forming properties are obtained.
Furthermore, the vinylidene chloride-vinyl chloride terpolymer has a melt viscosity significantly reduced by the addition of the MMA-BA copolymer. Therefore, the present invention particularly relates to a vinylidene chloride-vinyl chloride terpolymer. It is advantageous when used.

There is no limitation on the copolymerization composition of the vinylidene chloride-based copolymer, and it may be in the range in which the target melt viscosity can be obtained. For example, the content of vinylidene chloride can be 70% by mass or more. % Or more may be sufficient, and 90 mass% or more may be sufficient.
When the vinylidene chloride-based copolymer is a binary copolymer, for example, a binary copolymer of 70 to 97% by mass of vinylidene chloride and 3 to 30% by mass of another monomer copolymerizable with vinylidene chloride It may be

  In the present embodiment, the weight average molecular weight of the vinylidene chloride copolymer is 50,000 to 200,000, preferably 50,000 to 150,000, from the viewpoint of the melt viscosity.

  In the present embodiment, the polymerization form of the vinylidene chloride copolymer is not limited, and any of a random copolymer, a block copolymer, and a graft copolymer may be used.

In the present embodiment, the polymerization method of the vinylidene chloride copolymer is not particularly limited, and any known method such as a suspension polymerization method, an emulsion polymerization method, and a solution polymerization method can be employed. Among these, the suspension polymerization method is preferable. As the suspension polymerization method, a direct suspension method in which the monomer is added in water in which the suspension agent is dissolved, or as described in JP-A-62-280207, the suspension agent is dissolved in the monomer. An example is a suspension method in which water is added and the monomer phase is dispersed in a continuous phase / water in a discontinuous phase into a dispersion in which the monomer is discontinuous / water is a continuous phase.
Examples of oil-soluble initiators that can be used when the vinylidene chloride-based copolymer is produced by suspension polymerization include organic peroxides (eg, lauroyl peroxide, benzoyl peroxide, tert-butylperoxy- In addition to 2-ethylhexanoate, tert-butylperoxyisobutyrate, tert-butylperoxypivalate, tert-butylperoxyneodecanoate, diisopropylperoxydicarbonate etc., azobis compounds (eg, azobis compounds) And the like.
Examples of suspending agents that can be used when a vinylidene chloride-based copolymer is produced by a suspension polymerization method include, for example, cellulose derivatives such as methyl cellulose, ethyl cellulose and hydroxypropyl methyl cellulose, and partial saponals of polyvinyl alcohol or polyvinyl acetate. And the like.
Examples of water-soluble initiators that can be used when the vinylidene chloride copolymer is produced by emulsion polymerization include, in addition to inorganic peroxides (eg, sodium persulfate, potassium persulfate, ammonium persulfate, etc.) Organic peroxides (for example, redox systems of tert-butyl hydroperoxide and formaldehyde sodium sulfoxide, etc.) can be mentioned.
As an emulsifier which can be used when manufacturing a vinylidene chloride type copolymer by an emulsion polymerization method, for example, nonionic surfactant other than anionic surfactant (for example, sodium alkyl sulfonate, sodium alkyl benzene sulfonate etc.) Agents such as polyoxyethylene alkyl phenyl ether and the like.
When producing a vinylidene chloride-based copolymer, a chain transfer agent such as trichloroethylene, dodecyl mercaptan, octyl mercaptan, thioglycolic acid or 2-ethylhexyl thioglycolate may be added at the time of polymerization.
Although the polymerization temperature in particular in the case of manufacturing a vinylidene chloride type copolymer is not restrict | limited, Generally 20-100 degreeC is preferable, More preferably, it is 40-90 degreeC. After polymerization of the vinylidene chloride copolymer, known post treatments such as filtration, water washing, drying and the like can be carried out, if necessary. For example, when an emulsion is obtained by emulsion polymerization, salting out with aluminum sulfate or calcium chloride and the like, followed by post-treatment to obtain a powdery or granular vinylidene chloride copolymer. You can get it.

2. Acrylic copolymer The vinylidene chloride copolymer resin composition of the present embodiment comprises methyl methacrylate and an acrylic copolymer containing butyl acrylate as a monomer component (hereinafter referred to as "MMA-BA copolymer weight". Sometimes referred to as “coalescent”.

In the present embodiment, by causing the MMA-BA copolymer to coexist with the vinylidene chloride copolymer, the melt viscosity of the vinylidene chloride copolymer is lowered to thereby eliminate the uneven thickness, and the extrusion processability is obtained. Improve.
The reason why the melt viscosity of the vinylidene chloride copolymer decreases by the coexistence of the MMA-BA copolymer is not clear, but methyl methacrylate is compatible with the vinylidene chloride copolymer, and butyl acrylate is While incompatible, when a copolymer containing such compatible and incompatible components as a monomer component is made to coexist with a vinylidene chloride copolymer, the function of compatible methyl methacrylate is obtained. The butyl acrylate moiety of the MMA-BA copolymer collected around the vinylidene chloride copolymer molecules inhibits the vinylidene chloride copolymer molecules from assembling, resulting in entanglement of the polymer chains. It is thought that the viscosity decreases. However, the mechanism does not depend on this.

In general, when the components contained in the resin composition are incompatible with each other, the transparency thereof is reduced. However, although the reason has not been clarified after various investigations by the present inventor, butyl acrylate, when it is made to coexist with a vinylidene chloride copolymer, is different from other vinylidene chloride copolymers. It has been found that the transparency of the resin composition is not significantly reduced compared to the incompatible components.
And, in particular, when butyl acrylate is used in combination with methyl methacrylate (that is, copolymerized as MMA-BA copolymer) which is well compatible with vinylidene chloride copolymer, chloride is used. It has been found that the transparency of the resin composition containing the vinylidene copolymer as the main component is hardly reduced.

Furthermore, it was surprisingly found that the MMA-BA copolymer, even when added to a vinylidene chloride copolymer, has a small decrease in the gas barrier properties of the vinylidene chloride copolymer.
Vinylidene chloride-based copolymers are used in various applications, paying attention to the property that they have high gas barrier properties, but when the plasticizer etc. which are conventionally used to lower the melt viscosity are added, the gas barrier properties The decline in the rate was inevitable. Therefore, in the vinylidene chloride copolymer resin composition, it is a very advantageous effect that the melt viscosity can be lowered without impairing the gas barrier properties.

The MMA-BA copolymer used in the present embodiment may contain methyl methacrylate and butyl acrylate as a copolymer component, or may be a binary copolymer of these, or copolymerizable with these. It may be a ternary or higher copolymer further containing a monomer as a monomer component. Examples of monomers copolymerizable with these include, but are not limited to, aromatic vinyls such as styrene, α-substituted styrene, divinylbenzene, allyl methacrylate and the like.
The MMA-BA copolymer used in this embodiment is preferably a binary copolymer consisting only of methyl methacrylate and butyl acrylate, but may be a ternary copolymer, in which case methacrylic acid Preferred is a terpolymer of methyl, butyl acrylate and styrene.

  The copolymerization ratio of the MMA-BA copolymer used in the present embodiment is not limited, but it is preferable that the content (mol%) of butyl acrylate is smaller than methyl methacrylate, for example, a binary copolymer In some cases, it is preferable that the molar ratio (mol%) of the two be MMA / BA = 50 to 70/50 to 30, and in the case of a ternary copolymer, the total of MMA and BA be 100 It is preferable that the molar ratio (mol%) when doing is MMA / BA = 55-70 / 45-30.

There is no limitation on the form of polymerization of the MMA-BA copolymer used in the present embodiment, and any of random copolymer, block copolymer and graft copolymer may be used, but block or graft copolymer In some cases, in particular, the melt viscosity reducing effect tends to be excellent.
The MMA-BA copolymer may also be in the form of particles.

  There is no limitation on the polymerization method of the MMA-BA copolymer used in the present embodiment, and a known method can be adopted.

The weight average molecular weight of the MMA-BA copolymer used in the present embodiment is not limited, but from the viewpoint of the melt viscosity reduction effect, it is preferably 80,000 to 200,000.
Although the melt viscosity of the MMA-BA copolymer is not limited, it is preferably lower than the value expected for the vinylidene chloride copolymer composition, specifically 175 ° C., shear rate 100 (1 / s) It is preferable that the melt viscosity in these are 300-700 (Pa * s).
The melt viscosity at a shear rate of 100 (1 / s) at 175 ° C. can be measured by the method described in the examples below.

Furthermore, the oxygen permeability (O ₂ TR value) (cc / 15 μm · m ² · day · MPa) is preferably a value close to that of the vinylidene chloride copolymer, and by addition, the O ₂ TR value Is preferably not excessive.
Specifically, the increase rate (barrier magnification) at the time of comparison of O ₂ TR values before and after addition of MMA-BA copolymer is 1.5 times or less (that is, the same except that MMA-BA copolymer is removed) A chloride further including an M ₂ , MMA-BA copolymer, and an O ₂ TR value of a vinylidene chloride-based copolymer composition having the composition (a vinylidene chloride-based copolymer alone when no other than MMA-BA copolymer is added) When the O ₂ TR value of the vinylidene copolymer resin composition is B, B / A is preferably 1.5 or less.
The O ₂ TR value can be measured by the method described in the examples below.

3. Resin Composition The vinylidene chloride-based copolymer resin composition of the present embodiment contains the above-described vinylidene chloride-based copolymer and MMA-BA copolymer. The content of MMA-BA copolymer in the vinylidene chloride copolymer resin composition is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass, 0 More preferably, it is 0.5 to 3% by mass.
Even when the content is 0.05% by mass, the effect of lowering the melt viscosity is sufficiently obtained, but the gas barrier properties decrease as the content increases, so when the gas barrier properties are important, the content is 0.05 mass. % Or more and less than 0.5% by mass.

  The vinylidene chloride copolymer resin composition contains, in addition to the vinylidene chloride copolymer and the MMA-BA copolymer, other polymer compounds and other additives as long as the object of the present invention is not impaired. It can also be done. Although the content thereof is not limited, from the viewpoint of gas barrier properties, the total thereof preferably does not exceed the mass of the vinylidene chloride copolymer, and the content in the vinylidene chloride copolymer resin composition is More preferably, it is less than 12% by mass.

Examples of the above-mentioned other additives include plasticizers, nucleating agents, antistatic agents, flame retardants, lubricants, varnishes, stabilizers, and colorants such as pigments and dyes.
The plasticizer is generally added to improve the processability, which has the effect of lowering the elastic modulus of the material or lowering the melt viscosity of the resin, for example, dioctyl phthalate, acetyl citrate And carboxylic acid esters such as tributyl acid, dibutyl sebacate, dioctyl sebacate, acetylated glycerides and the like.
Examples of the lubricant include waxes such as oxidized polyethylene wax, paraffin wax, polyethylene wax, montanic acid ester wax, calcium montanate, fatty acid esters such as glycerin monoester, and mono or bisamides of fatty acids such as stearic acid amide.
Stabilizers are added for the purpose of suppressing various chemical reactions that may occur in materials, and examples thereof include antioxidants, hydrochloric acid collectors, light stabilizers, dispersants, UV absorbers, surfactants, Examples thereof include pH adjusters, and specific examples include vitamin E, alkyl thiopropionate, sodium pyrophosphate, ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, glycerin fatty acid ester, fatty acid amide and the like.
Among these additives, for example, those having various functions such as a plasticizer, a dispersion aid, and a lubricant are included.

In the present embodiment, in particular, the plasticizer and the stabilizer do not contain these from the viewpoint of the gas barrier property, or even if they contain them, the content of both (content ratio in the vinylidene chloride copolymer resin composition) The total of is 8 mass% or less.
Furthermore, in the present embodiment, from the viewpoint of gas barrier properties, the total content of all other additives including the plasticizer and the stabilizer (content ratio in the vinylidene chloride copolymer resin composition) is 8 It is preferably less than 7 wt%, more preferably less than 7 wt%, still more preferably less than 2 wt%, and particularly preferably less than 1.5 wt%.
Moreover, about a plasticizer, it is preferable that content in a vinylidene chloride-type copolymer resin composition is less than 0.2 mass%, it is more preferable that it is less than 0.1 mass%, and it does not contain at all Is particularly preferred.
The vinylidene chloride copolymer resin composition of the present embodiment has sufficiently low melt viscosity and can exhibit good extrusion processability, even if it does not contain a large amount of plasticizer and stabilizer.

It is preferable to add an additive having a hydrochloric acid collection effect to the resin composition of the present embodiment. It has been found that the thermal stability is remarkably improved when an additive having a hydrochloric acid collection effect is included in the low melt viscosity vinylidene chloride copolymer resin composition of the present embodiment.
When the vinylidene chloride copolymer is thermally decomposed, hydrochloric acid is generated, and this hydrochloric acid is considered as a catalyst to accelerate the dehydrochlorination. Therefore, although the above-mentioned hydrochloric acid is removed by adding an additive having a hydrochloric acid collection effect to the vinylidene chloride copolymer to suppress the acceleration of the dehydrochlorination by suppressing the acceleration of the dehydrochlorination, the improvement of the heat stability can be expected, In the case, the reason is not clear but this effect will be more pronounced.
Here, an additive having a hydrochloric acid collection effect (hereinafter sometimes referred to as "hydrochloric acid collector") is a mixture of 97 g of a vinylidene chloride copolymer and 3 g of the substance at 175 ° C. The amount of hydrochloric acid (dehydrochlorination amount) generated when heated for 15 minutes is 0.05 g (500 ppm) or less.

For example, an epoxy compound can be used as an organic collection agent as the hydrochloric acid collection agent. Specific examples of the epoxy compound are epoxidized vegetable oil, epoxidized fatty acid ester, bisphenol A epoxy resin and the like. Examples of epoxidized vegetable oils include epoxidized soybean oil, epoxidized linseed oil, epoxidized cottonseed oil, epoxidized safflower oil and the like.
Moreover, as an inorganic collection agent, inorganic ion exchangers, such as hydrotalcites and a zeolite, a metal oxide, a metal lead compound, a metal hydroxide, fatty acid metal soaps etc. can be used, for example For example, magnesium oxide, calcium oxide, zinc oxide, lead monoxide, lead trioxide, tribasic lead sulfate, dibasic lead phosphite, calcium hydroxide, sodium stearate, sodium stearate, magnesium stearate, calcium stearate Sodium hydrogen carbonate, sodium carbonate, ammonia, magnesium hydroxide, copper hydroxide, aluminum hydroxide, iron hydroxide and the like can be used, and these can be used alone or in combination.
The hydrotalcites are represented by the following general formula.
Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O
(In the formula, x is a number of 0 to 0.33, and m is a number of 0 to 2.)
The hydrotalcites represented by the above general formula can be produced by known methods, and commercial products are also widely sold. As a specific example of the commercial item which can be used in this embodiment, the brand name "ALCAMIZER" by Kyowa Chemical Industry Co., Ltd., "DHT-4" etc. are mentioned, for example.

In the present embodiment, the method for producing the vinylidene chloride copolymer resin composition is not limited, and the materials may be appropriately mixed in accordance with the usual method. There is no limitation on the mixing time of the vinylidene chloride copolymer with the MMA-BA copolymer or other additives, etc., and in the monomer state before the polymerization of the vinylidene chloride copolymer, the vinylidene chloride copolymer In the slurry state after polymerization, during the drying process after polymerization of the vinylidene chloride copolymer, after drying of the vinylidene chloride copolymer, any timing after polymer recovery may be used.
In the case of mixing after polymer recovery after polymerization of the vinylidene chloride copolymer, for example, a high speed mixer such as a Henschel mixer, a mixer such as a ribbon blender, a turn blender, or the like can be used.
With regard to the MMA-BA copolymer, a latex may be added at the time of drying.

In this embodiment, the melt viscosity of the vinylidene chloride copolymer resin composition at a temperature of 175 ° C. and a shear rate of 100 (1 / s) is set to 800 to 2300 (Pa · s). According to the composition of the present embodiment, the melt viscosity of the vinylidene chloride copolymer resin composition can be lowered to such a low value. The melt viscosity is more preferably 800 to 2000 (Pa · s), and still more preferably 800 to 1800 (Pa · s).
When the melt viscosity is in such a range, it is possible to prevent deviation of the resin amount in the resin flow direction during extrusion molding and flow spots generated in the flow path of the die etc. As a result, uneven thickness of the obtained molded body And surface roughness, transparency and surface gloss are improved. When the molded body is a thin film, a tube or the like, its thickness accuracy is improved.
In addition, when the melt viscosity is in such a range, the resin leakage frequency in the extruder decreases, and the extrusion amount per unit time can be increased, so that there is an advantage that productivity is improved. .
From such an advantage, excellent effects are exhibited even in single-layer extrusion molding such as wrap film and multilayer co-extrusion molding including other resin layers. Furthermore, fiber spinning such as melt spinning and wet spinning, and injection molding can exhibit the same effect, and are widely useful for various resin processing methods.

  In addition, the vinylidene chloride copolymer resin composition of the present embodiment may be processed in the state of high melt viscosity which is conventionally adopted when molding a vinylidene chloride copolymer alone, in which case Since the target melt viscosity can be achieved at a lower heating temperature, there is an economic effect of energy saving.

Oxygen permeability of the vinylidene chloride copolymer resin composition (O ₂ TR ^{values) (cc / 15μm · m 2} · day · MPa) is generally a copolymer composition of the vinylidene chloride copolymer contained in this However, the value is not limited and may be a value determined according to the application.

EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto.
In the following examples and comparative examples, the characteristics of the resin composition were measured as follows.
(1) Melt viscosity (Pa · s)
The shear rate and melt viscosity at a temperature of 175 ° C. and each load were measured using a flow tester CFT-500D (die hole diameter φ1 mm, die length 5 mm) manufactured by Shimadzu Corporation to obtain a melt viscosity curve.
The melt viscosity at a shear rate of 100 (1 / s) was obtained from the melt viscosity curve.
(2) Oxygen permeability deterioration rate (B / A)
The degree of deterioration (increase) in oxygen permeability (O ₂ TR value) (cc / 15 μm · m ² · day · MPa) due to the addition of the acrylic copolymer was evaluated.
The oxygen permeability of a film formed by extrusion forming a composition having the same composition except that the vinylidene chloride copolymer resin composition of the example and the comparative example and the acrylic copolymer are not added is a standard value (standard value O ₂ TR values: a) and then, in example, the oxygen permeability (added after O ₂ TR values of the evaluation film of the vinylidene chloride copolymer resin composition of the comparative example to which the ratio of B) (B / a) The oxygen permeability was evaluated as the deterioration rate of oxygen permeability (when the deterioration rate exceeds 1.5, the commercial value is significantly impaired, which is not preferable).
[Oxygen permeability deterioration rate] (B / A) = [O ₂ TR value after addition] / [Standard O ₂ TR value]
The measurement of the oxygen permeability was carried out on a film of 15 μm thickness under conditions of 23 ° C. and 65% RH using an oxygen permeability measuring device (Mocon OX-TRAN 2/20).
(3) Unevenness thickness Using the vinylidene chloride copolymer resin composition of Examples and Comparative Examples using a bench-top type offline contact-type thickness measuring device TOF-5R manufactured by Yamabun Electric Co., Ltd. The thickness (μm) in the flow direction of the film formed on was measured continuously. The measurement was performed on a 1 m long film, and the difference between the maximum value and the minimum value of the obtained measurement values was evaluated based on the following criteria.
Evaluation symbol Difference between maximum value and minimum value (μm)
0 0 or more and 2.0 or less ○ 2.0 or more and 5.0 or less △ 5.0 or more and 6.0 or less × 6.0 or more (4) Transparency (HAZE value)
The transparency of a 15 μm-thick film formed using the vinylidene chloride copolymer resin composition of the example and the comparative example in accordance with ASTM D-1003 is a turbidimeter (NDH manufactured by Nippon Denshoku Kogyo Co., Ltd. It measured on condition of 23 degreeC and 50% RH at 5000).
(5) Film Formability Using the apparatus shown in FIG. 1, the film formability of the vinylidene chloride copolymer resin compositions of Examples and Comparative Examples was evaluated as follows.
A vinylidene chloride-based resin composition is supplied from the hopper portion 102 of the extruder 101, propelled by a screw 103, heated and kneaded to melt and melted, and extruded from a slit portion of an annular die 104 attached to the tip of the extruder 101 I got a parison 105. The parison 105 was quenched with the cold water of the cooling tank 106, led to the pinch rolls A, A ′, and then preheated in the warm water tank 107, and led to the pinch roll groups B, B ′, C, C ′.
Next, air is sealed in the cylindrical parison 105, and the stretching operation is repeated 10 times according to the volume of air and the velocity ratio between the pinch rolls B, B ′, C, C ′, and all of the ten cylindrical films have no problem. Those that could maintain the 回, those that could maintain the tubular film 8 to 9 times out of 10 10, those that could maintain the tubular film 5 to 7 times out of 10 △, 0 to 4 out of 10 times The thing which was able to maintain the cylindrical film was made into x.
(6) Thermal stability (die separation interval)
It evaluates the thermal stability of the resin against the retention of the resin in the die. When the sliding property of the molten resin with the wall surface inside the die is poor, the retained resin is thermally deteriorated and adheres to the inside of the die. When the degree becomes serious, unevenness of thickness of film or the like occurs. If streaks continuously occur or the film thickness and thin spots become significantly worse, the extruder must be stopped and the die must be disassembled and cleaned, resulting in a significant decrease in production efficiency. The length of time of continuous extrusion until reaching such a state was evaluated based on the following criteria.
Evaluation symbol Time until continuous extrusion can not be performed 4000 4000 hours or more ○ 1000 hours or more and less than 4000 hours 100 100 hours or more and less than 1000 hours × less than 100 hours (7) Weight average molecular weight Polystyrene with the following equipment and conditions It was determined by gel permeation chromatography as a standard.
GPC: Shimadzu Corporation LC-10 AD
Column: Showa Denko KK Shodex Asahipak GS-710 7E in combination with GS-310 7E Measurement temperature: 40 ° C.
Measurement concentration: 0.3 mass% sample was dissolved in a solvent of hexamethyl phosphate triamide

Example 1
As a vinylidene chloride copolymer, a binary copolymer of vinylidene chloride and vinyl chloride (SP value: 9.5 (cal / cm ³ ) ^1/2 ) (vinylidene chloride: 88% by mass, vinyl chloride: 12% by mass, Weight average molecular weight 90,000), a ternary copolymer of methyl methacrylate, butyl acrylate and styrene as an MMA-BA copolymer (methyl methacrylate: 35 mol%, butyl acrylate: 20 mol%, styrene: 45 mol%, weight average molecular weight 100,000, (made by Kaneka Corporation, PA-101) were used.
MMA-BA copolymer, plasticizer (tributyl acetyl citrate (hereinafter referred to as ATBC, ATBC manufactured by Asahi Kasei Finechem Co., Ltd.), dibutyl sebacate (the ATBC, manufactured by Asahi Kasei Finechem Co., Ltd.) so as to be the mass% shown in Table 1 with respect to the vinylidene chloride copolymer. Add DBS, Taoka Chemical Industry Co., Ltd. DS-80)), and hydrochloric acid collector (epoxidized soybean oil (hereinafter ESO, NOF Corporation Newsizer 510R)) and mix using a Henschel mixer The resin composition was obtained.

Example 2
A point of using a vinylidene chloride-vinyl chloride binary copolymer (vinylidene chloride: 83% by mass, vinyl chloride: 17% by mass, weight average molecular weight 120,000) as a vinylidene chloride-based copolymer, and MMA-BA A resin composition was obtained in the same manner as in Example 1 except that the content ratio of the copolymer, ATBC, DBS and ESO was changed as shown in Table 1.

[Example 3]
A point of using a vinylidene chloride-vinyl chloride binary copolymer (vinylidene chloride: 88% by mass, vinyl chloride: 12% by mass, weight average molecular weight 110,000) as a vinylidene chloride-based copolymer, and MMA-BA A resin composition was obtained in the same manner as in Example 1 except that the content ratio of the copolymer, ATBC, DBS and ESO was changed as shown in Table 1.

[Examples 4 and 7]
A point of using a vinylidene chloride-vinyl chloride binary copolymer (vinylidene chloride: 90% by mass, vinyl chloride: 10% by mass, weight average molecular weight 120,000) as a vinylidene chloride-based copolymer, and MMA-BA A resin composition was obtained in the same manner as in Example 1 except that the content ratio of the copolymer, ATBC, DBS and ESO was changed as shown in Table 1.

[Example 5]
MMA-BA copolymer: a binary copolymer of methyl methacrylate and butyl acrylate (methyl methacrylate: 55 mol%, butyl acrylate: 45 mol%, weight average molecular weight: 200,000) (Mitsubishi Rayon Co., Ltd.) A resin composition was obtained in the same manner as in Example 4 except that L-1000) manufactured by a company was used.

[Example 6]
MMA-BA copolymer, using a vinylidene chloride-vinyl chloride binary copolymer (vinylidene chloride: 90% by mass, vinyl chloride: 10% by mass, weight average molecular weight 120,000) as a vinylidene chloride-based copolymer The content ratio of ATBC, DBS and ESO was changed as shown in Table 1, and Example 1 was repeated except that polyethylene wax (Hi Wax 320P manufactured by Mitsui Chemicals, Inc.) was added in an amount to become the mass% shown in Table 1. A resin composition was obtained in the same manner.

Comparative Example 1
Containing ATBC, DBS and ESO using a vinylidene chloride-vinyl chloride binary copolymer (vinylidene chloride: 90% by mass, vinyl chloride: 10% by mass, weight average molecular weight 120,000) as a vinylidene chloride-based copolymer The ratio was changed as shown in Table 1, and a resin composition was obtained in the same manner as Example 1 except that the MMA-BA copolymer was removed.

[Example 8]
Binary copolymer of vinylidene chloride and methyl acrylate (SP value: 10.0 (cal / cm ³ ) ^1/2 ) as vinylidene chloride copolymer (vinylidene chloride: 95% by mass, methyl acrylate: 5 mass) Using the same methyl methacrylate, butyl acrylate and styrene terpolymer (PA-101) as in Example 1 as a MMA-BA copolymer MMA-BA copolymer and hydrochloric acid collector (ESO) are added so as to be% by mass shown in Table 1 with respect to the vinylidene chloride copolymer, and the resin composition is mixed by a Henschel mixer. Obtained.

[Example 9]
A resin composition was prepared in the same manner as in Example 8 except that the same methyl methacrylate / butyl acrylate binary copolymer (L-1000) as that used in Example 5 was used as the MMA-BA copolymer. I got a thing.

[Example 10]
Furthermore, a resin composition was prepared in the same manner as in Example 9 except that hydrotalcite (HT) (manufactured by Kyowa Chemical Industry Co., Ltd., ALCAMIZER 2) as a hydrochloric acid collecting agent was added so as to be% by mass shown in Table 1. Obtained.

Comparative Example 2
A resin composition was obtained in the same manner as in Example 8 except that the amount of MMA-BA copolymer (PA-101) added was changed to the amount by mass% shown in Table 1.

Comparative Example 3
A resin composition was obtained in the same manner as in Example 8 except that the MMA-BA copolymer was not contained.

[Example 11]
A binary copolymer of vinylidene chloride and methyl acrylate (SP value: 10.0 (cal / cm ³ ) ^1/2 ) as a vinylidene chloride copolymer (vinylidene chloride: 92% by mass, methyl acrylate: 8 mass) %, A weight average molecular weight of 70,000) using the same terpolymer of methyl methacrylate, butyl acrylate and styrene (PA-101) as the one used in Example 1 as the MMA-BA copolymer Then, add MMA-BA copolymer and hydrochloric acid collector (ESO) in an amount to be% by mass shown in Table 1 with respect to the vinylidene chloride copolymer, and mix them with a Henschel mixer to obtain a resin composition. Obtained.

Comparative Example 4
A resin composition was obtained in the same manner as in Example 11 except that the hydrochloric acid scavenger (ESO) was not added.

  The compositions of Examples 1 to 11 and Comparative Examples 1 to 4 and the melt viscosity and thermal stability at a shear rate of 100 (1 / s) of the obtained vinylidene chloride copolymer resin composition at 175 ° C. It shows values of film forming property, uneven thickness, transparency and oxygen permeability deterioration rate (B / A).

The vinylidene chloride copolymer resin composition of the present invention has low melt viscosity and excellent extrusion processability and film forming property while maintaining the same transparency and gas barrier properties as a single vinylidene chloride copolymer. It can be used in various applications.
In particular, it can be suitably used as a material for thin molded articles such as films and tubes.

Claims (4)

A vinylidene chloride-based copolymer having a weight average molecular weight of 50,000 to 200,000, containing vinylidene chloride and another monomer copolymerizable with vinylidene chloride as a monomer component,
Methyl methacrylate and an acrylic copolymer containing butyl acrylate as a monomer component,
The melt viscosity at a shear rate of 100 (1 / s) is from 800 to 2300 (Pa · s) at 175 ° C.,
Containing no plasticizer and stabilizer, or the total content of both is 8% by mass or less,
Vinylidene chloride copolymer resin composition. The weight average molecular weight of the acrylic copolymer is 80,000 to 200,000.
The vinylidene chloride-based copolymer resin composition according to claim 1.   The vinylidene chloride-based copolymer resin composition according to claim 1 or 2, wherein the vinylidene chloride-based copolymer contains 70% by mass or more of vinylidene chloride as a monomer component. The O ₂ TR value (oxygen permeability) of a composition having the same composition as the vinylidene chloride copolymer resin composition except that the acrylic copolymer is removed is A,
The O ₂ TR value of the vinylidene chloride copolymer resin composition is B,
The vinylidene chloride-based copolymer resin composition according to any one of claims 1 to 3, wherein B / A is 1.5 or less.