KR20030057390A - Polyvinylidene chloride resin composition, stretched film and production processes thereof - Google Patents

Abstract

A polyvinylidene chloride resin composition comprising a polyvinylidene chloride resin, an additive that is liquid at room temperature, an additive that is solid at room temperature, and flaky inorganic powder.

The manufacturing method of the resin composition using the powder resin of polyvinylidene chloride resin.

A stretched film formed from a polyvinylidene chloride resin composition containing flaky inorganic powder and having a reflectance of 10 or more and a haze value of 8% or more.

The manufacturing method of the stretched film using the polyvinylidene chloride resin composition containing flaky inorganic powder.

Description

Polyvinylidene chloride resin composition, stretched film and manufacturing method thereof {POLYVINYLIDENE CHLORIDE RESIN COMPOSITION, STRETCHED FILM AND PRODUCTION PROCESSES THEREOF}

[Technical Field]

The present invention relates to a polyvinylidene chloride resin composition containing flaky inorganic powder and excellent in melt processability, stretchability, thermal stability, color tone, and the like, and a method for producing the same. Moreover, this invention relates to the stretched film excellent in metallic gloss formed from the polyvinylidene chloride resin composition containing flaky inorganic powder, and its manufacturing method. The stretched film according to the present invention is suitable for use as a packaging material for processed foods such as fish meat sausages and processed meat products.

Background Technology

In order to obtain a plastic molded article or a molded article having a metallic luster, it is known to mold or form a resin composition in which a metal powder is added to a thermoplastic resin. However, in the case of a resin composition in which a metal powder is added to a chlorine-containing thermoplastic resin such as polyvinyl chloride containing a chlorine atom (hereinafter abbreviated as "PVC") in a molecule, it is possible to obtain a molded or formed article having excellent metallic luster. It is difficult.

The reason for this is that when a resin composition containing a chlorine-containing thermoplastic resin and a metal powder is melt processed at a high temperature, a very small amount of chlorine atoms generated from the chlorine-containing thermoplastic resin reacts with the surface of the metal powder to discolor the metal powder. Presumably due to the fact

Japanese Patent Application Laid-Open No. 54-138048 proposes a resin composition containing a white pigment and / or a transparent white pigment together with a metal powder in a chlorine-containing thermoplastic resin as a solution to the above disadvantage. This publication discloses that 1 to 30 parts by weight of a white pigment and / or a transparent white pigment is added per 100 parts by weight of the metal powder in order to obtain a molded or formed product having excellent metallic luster, thereby preventing the fading or blackening of the metal powder. It is described.

Examples 1 to 3 of the publication disclose a composition obtained by adding a titanium oxide powder, a zinc oxide powder, or a calcium carbonate / aluminum mixed powder together with aluminum powder to a PVC. After kneading at 150 DEG C for 10 minutes by roll), an experimental example is described in which the composition is formed into a sheet having a metallic luster. Further, Example 4 of the above publication shows an experimental example in which pellets are prepared by melt kneading a composition obtained by adding clay together with aluminum powder to PVC, and a pipe is manufactured by an extruder using the pellets. .

As described above, this publication only shows examples in which PVC is used as the chlorine-containing thermoplastic, and does not present any examples using polyvinylidene chloride (hereinafter abbreviated as "PVDC"). When the resin is melted and kneaded with aluminum powder and the kneaded product is molded or formed, it is difficult to obtain a molded or formed article having excellent metallic luster even when a white pigment and / or a transparent white pigment are added. In particular, it is difficult to form a stretched film using a resin composition containing a PVDC resin and an aluminum powder.

PVDC resin is easy to decompose under melt processing conditions because the softening temperature is close to the decomposition temperature, and has poor thermal stability as compared to PVC. Therefore, when PVDC resin is used as the chlorine-containing thermoplastic resin, it is difficult to effectively prevent the discoloration or blackening of the metal powder due to the reaction with chlorine atoms generated by thermal decomposition during melt processing. In order to prevent fading or blackening of the metal powder, when increasing the amount of the added white pigment and / or the transparent white pigment, the color tone of the resultant molding or forming of the PVDC resin is whitened, thereby impairing important metallic luster. In addition, when the amount of the white pigment and / or the transparent white pigment added is increased, the melt processability of the PVDC resin is remarkably degraded, so that a part of the resin containing the pigment remains at the die outlet, and this remaining material is a decomposition product. As a result, the mixture is mixed with the formed product, thereby degrading the quality of the formed product or forming a linear pattern, thereby impairing the appearance of the formed product. Therefore, it is difficult to extrude a sheet or a film excellent in metallic luster and appearance.

Japanese Patent Laid-Open No. 11-254607 proposes a method for producing a coating film having a coating of vinylidene chloride copolymer containing 10 to 60% by weight of flaky aluminum by a coating method, rather than a melt kneading method. More specifically, the publication coats the base film with a dispersion containing vinylidene chloride copolymer (a) and flaky aluminum (b) in a weight ratio (a: b) of 90:10 to 60:40 and dried it. Thereby, a method of producing a coating film having a coating of vinylidene chloride copolymer containing flaky aluminum is proposed (claim 1).

The method described in this publication can be applied to a method for producing a coating film (ie, an unstretched film) having a coating of vinylidene chloride copolymer on a base film, but not to a method for producing other formed products such as a stretched film. .

Such a coating can be formed by drying the dispersion at a relatively low temperature in a short time after the coating step. However, the resin composition in which flaky aluminum is contained in vinylidene chloride resin (i.e., PVDC resin) in a large amount of about 10 to 60% by weight is poor in melt processability and stretchability, and therefore, for example, it is formed of a stretched film. It is difficult. When the stretched film is produced, poor appearance, delamination and the like are realized. In addition, according to the coating method, flaky aluminum is present in a state where its substantially original shape is maintained, so flaky aluminum cannot be finely dispersed in the resin.

On the other hand, even when the resin composition in which spherical metal powder is mixed is formed into a formed article, it is difficult to obtain a formed article having excellent metallic luster because the orientation effect of the composition is poor.

Since PVDC resin has an excellent gas barrier property, it is formed of a single layer or multilayer stretched film and is usually used as a packaging material for processed foods such as fish sausage and processed meat products. To date, the packaging has been colored with a red pigment. However, those with metallic luster, such as silver or gold, are required in accordance with changes in the consumer's preferences or local circumstances.

However, in view of the level of the prior art, incorporating flaky metal powder into PVDC resin having poor thermal stability, even when producing a molded article such as a stretched film, a molded article having satisfactory metal gloss and appearance is obtained. It was not foreseen. In fact, forming a stretched film with good metallic luster using PVDC resin has not been proposed before.

An object of the present invention is to provide a polyvinylidene chloride resin composition capable of producing a stretched film having a metallic luster and excellent in melt processability, stretch processability, thermal stability, color tone, and the like, and a method for producing the stretched film.

It is still another object of the present invention to provide a stretched film having excellent metallic luster using a polyvinylidene chloride resin having excellent melt processability and the like, and a manufacturing method thereof.

The present inventors conducted earnest research to achieve the above objects. As a result, when the flaky inorganic powder is mixed with a PVDC resin containing a specific additive, a resin composition which does not blacken or fade at all, without adding any white pigment or a transparent white pigment, and a stretched film having excellent metallic luster Is provided.

In particular, a solid additive and a part of a liquid additive such as an epoxy compound or a plasticizer are sequentially added to the powder resin of the PVDC resin containing the residual liquid additive at the time of polymerization, and then flaky inorganic powder is added to form the compound. And a stretched film using the compound, the stretched film can be easily provided as a stretched film having excellent metallic luster.

The stretched film according to the present invention is excellent in metallic luster as exemplified by its reflectance of 10 or more, and also excellent in maskability as exemplified by its haze value of 8% or more. The stretched film according to the present invention may be provided as a heat shrinkable film having a shrinkage rate in at least one direction of 10% or more when immersed in hot water at 100 ° C. for 3 minutes. The stretched film according to the present invention can be adjusted not only to the color tone due to flaky inorganic powder (for example, silver) but also to another color tone such as gold by using an organic pigment in combination.

According to the production method of the present invention, by stretching the PVDC resin composition containing the flaky inorganic powder and surface-aligning the flaky inorganic powder, a stretched film having a metallic luster having excellent texture, even color tone, and high maskability is obtained. Can be provided. The stretched film according to the present invention is excellent in metallic luster and suitable for heat shrinkability because of the orientation effect.

The present invention has been completed based on the above findings.

According to the present invention, there is provided a polyvinylidene chloride resin composition comprising:

(A) polyvinylidene chloride resin,

(B) at least one additive which is liquid at room temperature, selected from the group consisting of epoxy compounds and plasticizers,

(C) at least one additive which is solid at room temperature selected from the group consisting of epoxy group-containing resins, lubricants and fillers, and

(D) flaky inorganic powder

[here,

The content of flaky inorganic powder (D) is 0.03 to 4 parts by weight per 100 parts by weight of the polyvinylidene chloride resin,

At least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C) is contained at a ratio of 0.05 to 6 parts by weight per 100 parts by weight of the polyvinylidene chloride resin] .

According to the invention, there is also provided a stretched film formed from the polyvinylidene chloride resin composition, characterized by the following (1) to (3):

(1) the polyvinylidene chloride resin composition contains flaky inorganic powder in a ratio of 0.03 to 4 parts by weight per 100 parts by weight of polyvinylidene chloride resin,

(2) the reflectance of the film is 10 or more,

(3) The haze value of the said film is 8% or more.

According to the invention, there is also provided a process for the preparation of polyvinylidene chloride resin composition, which comprises a series of the following steps (I) to (IV):

(I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A);

(II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers;

(III) adding to the powder resin the total amount of the additive (B) which is liquid at room temperature, or the remaining amount of the additive (B) which is liquid at room temperature which was used as necessary in step (I);

(IV) adding flaky inorganic powder (D) to the powdered resin

Wherein at least one epoxy heat stabilizer selected from the group consisting of epoxy compounds in component (B) and epoxy group containing resins in component (C) is added in at least one of steps (I) to (III).

According to the present invention, there is also provided a process for producing a stretched film made of a polyvinylidene chloride resin composition, which comprises a series of the following steps (I) to (V):

(I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A);

(II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers;

(III) adding to the powder resin the total amount of the additive (B) which is liquid at room temperature, or the remaining amount of the additive (B) which is liquid at room temperature which was used as necessary in step (I);

(IV) adding flaky inorganic powder (D) to said powder resin; And

(V) preparing a stretched film using the compound obtained through each step

Wherein at least one epoxy heat stabilizer selected from the group consisting of epoxy compounds in component (B) and epoxy group containing resins in component (C) is added in at least one of steps (I) to (III).

1.Polyvinylidene chloride resin (PVDC resin) :

The PVDC resin used in the present invention is a copolymer composed of 60 to 98% by weight (by mass) of vinylidene chloride and 2 to 40% by weight of another monomer copolymerizable therewith. For homopolymers of vinylidene chloride, its softening temperature is close to the decomposition temperature and it is difficult to plasticize it using a plasticizer. For this reason, internal plasticization and thermal stabilization by copolymerization using another comonomer have been attempted.

Examples of such comonomers include vinyl chloride; Alkyl esters of acrylic acid (carbon number from 1 to 18 in the alkyl group) such as methyl acrylate, ethyl acrylate, butyl acrylate and lauryl acrylate; Alkyl esters of methacrylic acid (carbon number from 1 to 18 in the alkyl group) such as methyl methacrylate, butyl methacrylate and lauryl methacrylate; Vinyl cyanide such as acrylonitrile; Aromatic vinyl compounds such as styrene; Vinyl esters of aliphatic carboxylic acids having 1 to 18 carbon atoms, such as vinyl acetate; Alkyl vinyl ethers having 1 to 18 carbon atoms; Vinyl polymerizable unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid; And alkyl esters of vinyl polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid and itaconic acid (including partial esters; carbon number in the alkyl group: 1 to 18).

The comonomers can be used alone or in any combination thereof. Of these comonomers, vinyl chloride, methyl acrylate and lauryl acrylate are preferred. If the proportion of the comonomer to be copolymerized is too low, the internal plasticization of the resulting copolymer is insufficient, resulting in poor melt processability. If the proportion of the comonomer to be copolymerized is too high, the gas barrier property of the resulting copolymer is lowered. The proportion of the comonomer to be copolymerized is preferably 3 to 35% by weight, more preferably 3 to 25% by weight.

The reduced viscosity [ηsp / C] of the PVDC resin used in the present invention is preferably 0.035 to 0.070 (L / g) in view of melt processability, stretchability, suitability for packaging machines, cold resistance, and the like during film formation. ), More preferably 0.040 to 0.067 (l / g), particularly preferably 0.045 to 0.063 (l / g). When the reduced viscosity of the PVDC resin is too low, the stretchability of the resulting resin composition is lowered, and the mechanical properties of the resulting stretched film are lowered. Therefore, it is not preferable to use any PVDC resin whose reduction viscosity is too low as above. When the reduction viscosity of the said PVDC resin is too high, the melt workability of the produced resin composition will fall, and the said resin composition shows the tendency to color. Therefore, it is not preferable to use any PVDC resin having a too high reduction viscosity as described above.

Two or more kinds of PVDC resins having different reducing viscosities may be used in combination. When flaky inorganic powder is added to the said PVDC resin, melt workability and extending | stretching workability fall. Therefore, it is preferable to prepare a blend of two or more PVDC resins having different reducing viscosities from each other, so as to obtain a reducing viscosity within the above range in order to improve the properties. As a result, a stretched film having excellent mechanical properties and good metallic luster can be obtained. More specifically, a combination of a PVDC resin having a relatively low reduction viscosity of 0.035 to 0.055 and a PVDC resin having a relatively high reduction viscosity of more than 0.055 and less than 0.070 may be mentioned.

The PVDC resin may be blended with any other resin if desired. As examples of other resins, ethylene-vinyl acetate copolymers, (meth) acrylic ester (co) polymers and methyl methacrylate-butadiene-styrene terpolymers can be mentioned. As the methacrylic ester (co) polymer, a (co) polymer of an alkyl ester of (meth) acrylic acid (with 1 to 18 carbon atoms in the alkyl group) is preferable, and a methyl (meth) acrylate-butyl (meth) acrylate copolymer More preferred. Other resins are generally used in proportions up to 20 parts by weight per 100 parts by weight of PVDC resin.

Among these other resins, ethylene-vinyl acetate copolymers (hereinafter abbreviated as "EVA") are preferred. EVA, preferably having a vinyl acetate content of 20 to 40% by weight, more preferably 28 to 35% by weight, and preferably 1 to 50 g / 10 minutes, more preferably 10 to 40 g / 10 minutes EVA having a melt flow rate (MFR) is preferred. By blending the EVA with the PVDC resin, the melt processability, sealing strength and the like of the resulting resin composition can be improved. The proportion of EVA to be blended is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight per 100 parts by weight of PVDC resin.

PVDC resin used in the present invention may be a resin synthesized by any polymerization process such as suspension polymerization, emulsion polymerization, solution polymerization. However, in order to form the compound as a powdered resin, a resin obtained by a suspension polymerization method having a particle size (resin particle size) in the range of 40 to 600 mu m and requiring no grinding step is preferable. Resin particle size can be measured by a dry sifting method using a standard sieve. As antioxidants, preferably plasticizers, epoxy compounds and / or the like can be incorporated into the PVDC resin during its polymerization.

2. Additives that are liquid at room temperature :

In this invention, it is preferable to use an epoxy compound and a plasticizer as an additive which is liquid at normal temperature (23 degreeC). These liquid additives are preferably used in combination.

As examples of such epoxy compounds, those used as heat stabilizers for chlorine-containing resins, such as epoxidized vegetable oils, epoxidized animal oils, epoxidized fatty acid esters and epoxy resin prepolymers, may be mentioned. Epoxy compounds that are liquid at room temperature are selected from these compounds and used alone or in any combination thereof.

As epoxidized vegetable oils and epoxidized animal oils used in the present invention, hydrogenated peroxide, peracetic acid and the like are used to epoxidize natural animal oils or vegetable oils having unsaturated bonds and to denature their double bonds to oxirane rings. Can be used. As epoxidized vegetable oil, epoxidized soybean oil, epoxidized linseed oil, etc. are preferable.

As epoxidized fatty acid esters, mention may be made of the epoxidized products of the above unsaturated fatty acid esters, such as epoxidized octyl stearate. The epoxy resin prepolymers include bisphenol A glycidyl ether and the like. Among the epoxy compounds, epoxidized vegetable oils are particularly preferred in the field of food packaging materials.

When an epoxy compound which is liquid at room temperature is used, it is generally used in a blending ratio of 0.1 to 6 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 1 to 4 parts by weight, per 100 parts by weight of the PVDC resin. . If the compounding ratio of the epoxy compound is too high, disadvantages such as bleeding, blocking, deterioration of gas barrier properties, and deterioration of color tone are likely to occur. When the compounding ratio of the said epoxy compound is too low, the effect of fully plasticizing PVDC resin falls, and also the effect of improving melt workability and thermal stability falls.

The epoxy compound is contained in the resin composition by allowing the epoxy resin to be contained in the powder resin of the PVDC resin formed in the polymerization step of the PVDC resin, or by combining an epoxy compound with the powder resin of the PVDC resin, or a combination thereof. Be sure to In order to allow the epoxy compound to be contained in the powder resin of the PVDC resin formed in the polymerization step, vinylidene chloride is copolymerized / copolymerized in the presence of an epoxy compound with a monomer copolymerizable therewith, or an epoxy compound is added after the copolymerization, Prepare a powdered resin of PVDC resin. When vinylidene chloride is copolymerized in the presence of a monomer copolymerizable with the epoxy compound, the epoxy compound is added in at least one of the initial polymerization step, the intermediate polymerization step and the late polymerization step to perform the copolymerization. In order to add the epoxy compound after copolymerization, the epoxy compound is generally added to a slurry containing the formed copolymer.

Among them, in order to stably blend the PVDC resin with the flaky inorganic powder, the epoxy compound is contained in the polymerization step of the PVDC resin for preparing the powder resin, and the balance of the epoxy compound is added to the powder resin at the time of blending. It is preferable to add. If desired, the entire amount of the epoxy compound used may be added during the polymerization or may be blended with the powdered resin.

Representative examples of plasticizers include polyester plasticizers such as dioctyl phthalate, tributyl acetylcitrate, dibutyl sebacate, dioctyl sebacate, acetylated monoglycerides, acetylated diglycerides, acetylated triglycerides, and the glycerides. Acetylated glycerides containing three or three, esters of adipic acid and 1,3-butanediol, esters of adipic acid and 1,4-butanediol, and mixtures of two or more such polyesters. Among the plasticizers, those which are liquid at room temperature are used. If a plasticizer is used, it is generally used in a blending ratio of 0.05 to 10 parts by weight per 100 parts by weight of PVDC resin.

The plasticizer is contained in the resin composition by allowing a plasticizer to be contained in the powder resin of the PVDC resin formed in the polymerization step of the PVDC resin, or blending a plasticizer with the powder resin of the PVDC resin, or using a combination thereof. Be sure to To ensure that the plasticizer is contained in the powdered resin of the PVDC resin formed in the polymerization step, the vinylidene chloride is copolymerized in the presence of a copolymerizable monomer with the copolymerizable monomer and / or co-polymerized, or the plasticizer is added after the copolymerization. A powdered resin of the resin is prepared. When vinylidene chloride is copolymerized in the presence of a copolymerizable monomer and a plasticizer, the plasticizer is added in at least one of the initial polymerization step, the intermediate polymerization step and the late polymerization step to perform the copolymerization. In order to add the plasticizer after copolymerization, the plasticizer is generally added to a slurry containing the formed copolymer.

Among them, it is preferable that the plasticizer is contained in the polymerization step of the PVDC resin to prepare the powder resin, and if necessary, an additional plasticizer is added to the powder resin at the time of blending. In addition, it is particularly preferable to mix the remaining amount of the plasticizer with the powdered resin at the time of blending. The entire amount of the epoxy compound used may be added during the polymerization or, if desired, to be blended with the powdered resin.

In the present invention, either or both of the epoxy compound and the plasticizer are used as additives which are liquid at room temperature. However, both are preferably used.

3. Additives that are solid at room temperature :

In the present invention, at least one selected from the group consisting of an epoxy group-containing resin, a lubricant and a filler is used as an additive which is a solid at room temperature (23 ° C). The epoxy group-containing resin, which is solid at room temperature, acts as a heat stabilizer and is generally used in the form of a powder.

The epoxy group containing resin is a resin having at least one epoxy group. Among others, glycidyl group-containing (meth) acrylic resins (hereinafter may be abbreviated as "GMA") are preferred. The glycidyl group-containing (meth) acrylic resin has preferred properties as a heat stabilizer.

As said glycidyl group containing (meth) acrylic-type resin, the copolymer containing the glycidyl ester of the vinyl fatty acid unsaturated fatty acid as a copolymerization component is preferable. Since the copolymers typically comprise (meth) acrylic esters such as glycidyl (meth) acrylate and (meth) acrylic esters which do not contain glycidyl groups as copolymerization components, in the present invention it is a glycidyl group It is called containing (meth) acrylic-type resin. In addition, the vinyl copolymer refers to a process in which a polymer is obtained by repeating an addition reaction of a compound having a carbon-carbon double bond, and an example of “glycidyl ester of a vinyl polymerizable unsaturated fatty acid” is broadly a carbon-carbon double Compounds having a bond, such as a vinyl compound and a vinylidene compound.

Preferred glycidyl group-containing (meth) acrylic resins include glycidyl esters of vinyl polymerizable unsaturated fatty acids, (meth) acrylic esters containing no glycidyl groups at all, and / or any other ethylenic copolymerizable therewith. Copolymers of unsaturated monomers.

Examples of glycidyl esters of vinyl polymerizable unsaturated fatty acids include glycidyl esters of (meth) acrylic acids such as glycidyl methacrylate, glycidyl acrylate, β-methylglycidyl methacrylate and β Methylglycidyl acrylate; And diglycidyl esters of unsaturated fatty acids such as maleic acid, fumaric acid and itaconic acid. The glycidyl esters of the vinyl polymerizable unsaturated fatty acids can be used alone or in any combination thereof. Among them, glycidyl group-containing (meth) acrylic esters such as glycidyl methacrylate are preferred.

Examples of (meth) acrylic esters that do not contain glycidyl groups include alkyl esters of acrylic acid (carbon number from 1 to 18 in the alkyl group) such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, Uryl acrylate and stearyl acrylate; And alkyl esters of methacrylic acid (carbon number from 1 to 18 in the alkyl group) such as methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and stearyl methacrylate Of these, methyl methacrylate and butyl acrylate are preferred. The (meth) acrylic esters may be used alone or in any combination thereof.

Examples of such other copolymerizable ethylenically unsaturated monomers include styrene, acrylonitrile, acrylic acid, vinyl chloride, vinylidene chloride and alkyl vinyl ethers. The ethylenically unsaturated monomers may be used alone or in any combination thereof. Among these, styrene is preferable.

As glycidyl group-containing (meth) acrylic resins, copolymers of 10 to 50% by weight of glycidyl esters of vinyl polymerizable unsaturated fatty acids and 50 to 90% by weight of one or more ethylenically unsaturated monomers copolymerizable therewith desirable. Among the copolymers, from 10 to 50% by weight of glycidyl esters of vinyl polymerizable unsaturated fatty acids, from 0 to 90% by weight of glycidyl group-containing (meth) acrylic esters and from 0 to 50% by weight Preferred are copolymers of other ethylenically unsaturated monomers of from 10 to 50% by weight of glycidyl esters of vinyl polymerizable unsaturated fatty acids, from 10 to 90% by weight of glycidyl group-free (meth) acrylic esters and from 0 to Particular preference is given to copolymers of 40% by weight of any other ethylenically unsaturated monomer. The coloring resin composition (coloring masterbatch) containing the pigment previously disperse | distributed to the said copolymer manufactured previously is preferable because pigment dispersibility can be improved.

Among the glycidyl group-containing (meth) acrylic resins, the content of glycidyl group-containing monomers, typically glycidyl esters of vinyl polymerizable unsaturated fatty acids, is preferably 10 to 50% by weight. If the content is too low, the miscibility of the resin and the PVDC resin is low, the thermal stability of the resulting resin composition is lowered, and the resulting packaging film is susceptible to color change over time. If the content of the glycidyl group-containing monomer component is too high, such copolymers will suffer from poor dispersion in the resin composition, and appearance defects such as fish eyes will likely be caused in the resulting stretched film.

Specific examples of glycidyl group-containing (meth) acrylic resins include glycidyl methacrylate-methyl methacrylate-styrene-butyl acrylate tetramer, glycidyl methacrylate-methyl methacrylate copolymer, and glycidyl Dyl methacrylate-methyl methacrylate-styrene trimer, glycidyl methacrylate-vinyl chloride copolymer, glycidyl methacrylate-methyl acrylate copolymer, glycidyl methacrylate-butyl acrylate aerial Copolymers and glycidyl methacrylate-vinylidene chloride copolymers.

The molecular weight of the glycidyl group-containing (meth) acrylic acid resin is not particularly limited. However, the weight average molecular weight (Mw) is generally on the order of 3,000 to 100,000, preferably about 5,000 to 50,000. If the weight average molecular weight (Mw) is too high, the resulting stretched film may cause an aggregate (fish eye). If the weight average molecular weight is too low, the resulting stretched film will cause blocking, which lowers the suitability for the packaging machine.

The epoxy value of glycidyl group containing (meth) acrylic-type resin is not specifically limited, 0.3 or more may be sufficient. In particular, an epoxy value of less than 0.3 is preferable because it is easy to make the pigment dispersibility, color tone, thermal stability, processability, gas barrier property, and the like highly balanced with each other. The epoxy value is preferably 0.25 or less, more preferably 0.2 or less. In many cases good results can be obtained when the epoxy value is between about 0.05 and 0.2. When the epoxy value of the said glycidyl group containing (meth) acrylic-type resin is too high, a fish eye etc. are easy to generate | occur | produce and a visual defect is likely to be caused to the produced | generated formation. On the other hand, when the said epoxy value is too low, the effect of improving thermal stability will fall.

The glycidyl group-containing (meth) acrylic resin is generally contained in a proportion of 0.05 to 5 parts by weight, preferably 0.08 to 3 parts by weight, and more preferably 0.1 to 2 parts by weight per 100 parts by weight of the PVDC resin. have. When the said compounding ratio is too low, there exists a tendency for the melt workability and thermal stability of the produced resin composition to fall. When the said compounding ratio is too high, the gas barrier property and cold resistance of the produced stretched film will fall, and it is difficult to achieve clear metallic gloss.

In the PVDC resin composition according to the present invention, it is essential to contain, as an epoxy heat stabilizer, any one or both of an epoxy compound which is liquid at room temperature and an epoxy group-containing resin that is solid at room temperature. The content of the epoxy heat stabilizer is in the range of 0.05 to 6 parts by weight, preferably 0.08 to 5 parts by weight, more preferably 0.1 to 4 parts by weight, per 100 parts by weight of the PVDC resin. If the content of the epoxy heat stabilizer is too low, the thermal stability of the resulting PVDC resin composition is lowered, making formation and processing difficult, blackening is caused, and the metal gloss of the resulting stretched film is also significantly damaged. If the content of the epoxy heat stabilizer is too high, the gas barrier and cold resistance of the resulting stretched film may be lowered, and fish eyes may be caused.

Examples of lubricants include those suitable for the melt processing of PVDC resins, including waxes such as polyethylene oxide waxes, paraffin waxes, polyethylene waxes, montanic acid ester waxes and calcium montanates; Fatty acid esters such as glycerol monoesters. Particularly suitable for melt processing of PVDC resins include mono or bisamides of fatty acids such as stearic acid amide. When these lubricants are used, they are used alone or in any combination thereof, in proportions of generally 0.001 to 2 parts by weight, preferably 0.05 to 1 part by weight, per 100 parts by weight of PVDC resin.

Examples of fillers include silicon dioxide and calcium carbonate. Silicon dioxide or calcium carbonate acts as a satinizing agent, a slippering agent to the film in a packaging machine, and the like. Silicon dioxide also acts as an inorganic lubricant. In addition, silicon dioxide is effective in preventing the aggregation of EVA in the compounding of EVA. When these fillers are used, they are generally used in a proportion of 0.001 to 1 parts by weight, preferably 0.03 to 0.5 parts by weight, per 100 parts by weight of PVDC resin.

4. Scaly inorganic powders :

Examples of flaky inorganic powders include mica, flaky graphite, and flaky metal powder. Among these, flaky metal powder is preferable, and flaky aluminum powder is more preferable.

By using the flaky inorganic powder, a resin composition and a stretched film having a desired color tone and metallic gloss can be provided. The flaky inorganic powder has a form where the dimension (a) with respect to the planar direction of the dimension (b) in the thickness direction of each particle is very thin. The ratio (a / b) between them is preferably 10 times or more, more preferably 30 times or more, and the upper limit thereof is about 100 times.

The average particle thickness of the flaky inorganic powder is preferably 0.15 to 0.70 mu m, more preferably 0.18 to 0.60 mu m. The average particle diameter of said flaky inorganic powder becomes like this. Preferably it is 1-100 micrometers, More preferably, it is 3-40 micrometers. The flaky inorganic powder, when sieved using a standard sieve having a nominal size of 45 μm, preferably has a sieve passage speed of at least 70%, more preferably at least 80%. The average particle diameter of the flaky inorganic powder and the like can be measured by laser diffraction. According to the said laser diffraction method, a sample can be disperse | distributed in ethanol, and a measurement can be performed using a particle diameter distribution measuring apparatus and a Microtrack FRA9220 model (made by Nikkkiso Co., Ltd.).

Flaky inorganic powders, such as flaky aluminum powder, can be surface treated at or after their preparation. Treatment with higher fatty acids is a typical surface treatment. The higher fatty acid is preferably a fatty acid having 14 to 22 carbon atoms, such as stearic acid or oleic acid. The higher fatty acids are preferably solid at room temperature. The scaly inorganic powder to be surface-treated can impart proper lubricity to the resulting PVDC resin composition, and improve its melt processability. When the flaky inorganic powder is used in combination with an organic pigment, the flaky inorganic powder treated with a higher fatty acid can improve the dispersibility of the organic pigment. By surface-treating the said flaky inorganic powder, a flaky inorganic powder can be prevented from coloring by oxidation or reaction with a chlorine atom.

The flaky inorganic powder is used in a blending ratio of 0.03 to 4 parts by weight, preferably 0.05 to 3 parts by weight, per 100 parts by weight of PVDC resin. If the blending ratio of the flaky inorganic powder is too low, it is difficult to obtain a formed article such as a stretched film having a desired metallic luster. When the blending ratio of the flaky inorganic powder is too high, workability such as melt workability and stretch workability of the resulting resin composition is lowered. In addition, when the blending ratio of the flaky inorganic powder is too high, disadvantages such as delamination of a formed article such as a stretched film and rough surface feel are likely to occur. By carrying out the mixing | blending ratio of the said flaky inorganic powder in the said range, the stretched film excellent in the metallic luster which has a tint like silver can be provided. Further, by keeping the blending ratio of the flaky inorganic powder within the above range, by using it in combination with a small amount of organic pigment, a metallic luster of a desired color tone such as gold can be imparted.

When spherical metal powder is used, it shows a tendency for the melt workability of the produced PVDC resin composition to fall in addition to the point which is a metal powder, but its handleability is difficult. The resin composition as described above was poor in stretchability and a stretched film excellent in metallic luster was not obtained. The spherical metal powder is generally dispersed in petroleum spirit.

5. Organic Pigments :

In the present invention, a molded article such as a stretched film can be provided as a molded article having a metallic shine of another hue such as gold by using a flaky inorganic powder in combination with an organic pigment as well as a hue resulting from flaky inorganic powder. have.

As examples of organic pigments, mention may be made of organic pigments of the type azo, phthalocyanine, quinacridone. Among them, a combination of a red organic pigment, a yellow organic pigment, and both organic pigments is preferable.

When a flaky inorganic powder such as flaky aluminum powder is used in combination with an organic pigment such as a red organic pigment and / or a yellow organic pigment, another color tone, such as gold, in addition to a tint such as silver due to the flaky inorganic powder A stretched film having a metallic luster of, clear hue, and giving a luxurious feeling can be provided.

When the organic pigment is added, its blending ratio is preferably 0.001 to 3 parts by weight, more preferably 0.05 to 2 parts by weight, per 100 parts by weight of PVDC resin.

6. Other additives :

To the resin composition and the stretched film according to the present invention, other pigments, other heat stabilizers, surfactants, antioxidants, other stabilizers, ultraviolet absorbers, pH adjusters and the like may be added as necessary. As examples of other pigments, zinc oxide, magnesium oxide, clay and talc may be mentioned.

As examples of surfactants, nonionic surfactants such as sorbitan fatty acid esters, glycerol fatty acid esters, polyglycerol fatty acid esters and polyoxyethylene sorbitan fatty acid esters may be mentioned, and an appropriate amount of the above surfactants is used if necessary. . Glycerol fatty acid esters (mono-, di- and tri-esters), sorbitan fatty acid esters (mono-, di- and tri-esters) and the like serve as internal release agents for stretched films for packaging materials. The surfactants may be used alone or in any combination thereof.

As examples of antioxidants, phenolic antioxidants such as α-, β-, γ- and δ-tocopherol, 2,6-di-tert-butyl-4-methylphenol (BHT), triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate (Irganox 245, manufactured by CIBA-GEIGY AG), 2,4-dimethyl-6-S-alkylphenol, 2,4-dimethyl -6- (1-methylpentadecyl) phenol and mixtures thereof (Irganox 1411, manufactured by CIBA-GEIGY AG); Thioether antioxidants such as thiodipropionic acid and distearyl thiodipropionate (DSTDP); And phosphite antioxidants such as distearylpentaerythritol diphosphite. The antioxidant is used at a ratio of generally 0.0001 to 0.05 parts by weight per 100 parts by weight of PVDC resin.

Other stabilizers include inorganic bases such as magnesium hydroxide, magnesium oxide, calcium linoleate and calcium hydroxyphosphate; Salts of citric acid and organic weak acids such as alkali metal salts of citric acid; And salts of ethylenediaminetetraacetic acid can be mentioned. These may be used in appropriate amounts.

Examples of ultraviolet absorbers include 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole. These may be used in an appropriate amount as necessary.

The pH adjuster comprises sodium pyrophosphphenite and disodium dihydrogenpyrophosphate and is used at a rate of 0.5 parts by weight per 100 parts by weight of PVDC resin. The pH adjuster is generally used in the preparation of the PVDC resin.

The epoxy compound, the plasticizer, the surfactant, and the like act as a dispersion aid for enhancing the dispersibility of flaky inorganic powders and organic pigments. However, in addition to these, glycerol and propylene glycol; And oligomers and polymers of aliphatic hydrocarbons or aromatic hydrocarbons may be mentioned as dispersion aids. Among these, oligomers of aliphatic hydrocarbons having 2 to 8 carbon atoms are preferred. Particular preference is given to using liquid aliphatic hydrocarbon oligomers having a weight average molecular weight of 300 to 5,000. The said dispersing aid has the effect | action which improves the dispersibility of flaky inorganic powder and an organic pigment, or prevents scattering thereof, and has a fall application of a melt processing temperature. The dispersing aid is generally used at a ratio of 2 parts by weight or less per 100 parts by weight of PVDC resin.

The additives are generally added to and blended with the powdered resin of the PVDC resin. However, in addition to or in combination with the compounding step, additives can be included in the PVDC resin by adding them to the monomer mixture in their polymerization step of polymerizing them, by adding them to the slurry after the polymerization, or by using a combination thereof. have.

7.PVDC resin composition and its preparation method :

The PVDC resin composition according to the present invention is composed of at least one additive (B) which is liquid at room temperature, selected from the group consisting of polyvinylidene chloride resin (A), an epoxy compound and a plasticizer, an epoxy group-containing resin, a lubricant and a filler. It is a resin composition containing at least 1 type of additive (C) which is solid at normal temperature selected from the group, and flaky inorganic powder (D).

According to the PVDC resin composition, the content of the (D) flaky inorganic powder is 0.03 to 4 parts by weight per 100 parts by weight of the polyvinylidene chloride resin. According to the present invention, the PVDC resin composition contains as essential components at least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C). The content of the epoxy heat stabilizer is 0.05 to 6 parts by weight per 100 parts by weight of the polyvinylidene chloride resin. The PVDC resin composition according to the present invention may further contain an organic pigment (E), EVA (F) and the like as necessary.

In the PVDC resin composition according to the present invention, the flaky inorganic powder is preferably flaky aluminum powder. In the PVDC resin composition according to the present invention, it is preferable that the PVDC resin is a powder resin, and the form of the resin composition is a compound. In the case of melt kneading the respective components before the resin composition is melt processed, the PVDC resin is easily decomposed, and thus disadvantages such as discoloration and blackening of the flaky inorganic powder are likely to occur. In view of the thermal stability of the PVDC resin, either or both of the epoxy compound in component (B) and the epoxy group-containing resin in component (C) is contained in the PVDC resin composition.

In the present invention, the PVDC resin composition may be suitably prepared through the following steps (I) to (IV):

(I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A);

(II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers;

(III) adding to the powder resin the total amount of the additive (B) which is liquid at room temperature, or the remaining amount of the additive (B) which is liquid at room temperature which was used as necessary in step (I); And

(IV) adding flaky inorganic powder (D) to said powder resin.

At least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C) is added in at least one of steps (I) to (III).

The addition of the epoxy heat stabilizer is carried out by making it present in the copolymerization reaction system or by adding it to the powdered resin. The proportion of the individual components used is the same as in the PVDC resin composition.

The PVDC resin is preferably a resin obtained by adding an additive, which is liquid at room temperature, to the monomer composition during synthesis, and polymerizing the mixture. Even in this case, it is preferable that an additive which is liquid at room temperature is added at the time of compounding. In other words, it is preferable that some of the additives which are liquid at room temperature are used in the polymerization, and the residues are used in the compounding. However, the entire amount of the additive which is liquid at room temperature may be added during polymerization or blending. The blending ratio of said individual components is preferably selected from said range.

In another preferred method of producing a PVDC resin composition according to the present invention, the powder resin of the PVDC resin is blended with respective additives, so that the PVDC resin maintains the form of the powder resin, ). The compounding temperature is preferably controlled at 85 ° C or lower, more preferably 80 ° C or lower. Additives which are liquid at room temperature, such as epoxidized vegetable oils or plasticizers, are absorbed into the powdered resin by blending. The additive, which is solid at room temperature, adheres to the periphery of the powdered resin at the time of blending.

When additives which are liquid at room temperature are added in portions in steps (I) and (III), the ratio (weight ratio) of the liquid additive added between each step is preferably 10:90 to 90:10, more preferably Is 20:80 to 80:20, particularly preferably 30:70 to 70:30.

In order to adjust the color tone, an organic pigment (E) can be added in step (IV) together with the flaky inorganic powder (D). Also in the above step (III), a glycidyl group-containing (meth) acrylic resin composition containing an organic pigment may be contained as an epoxy group-containing resin. As said flaky inorganic powder (D), flaky aluminum powder is preferable. After step (IV), the step of further adding ethylene-vinyl acetate copolymer (F) can be arranged.

Since the PVDC resin composition according to the present invention is excellent in melt processability, stretch processability, heat resistance, and the like, it can be formed into various formed products by melt extrusion, stretch processing, and / or the like. The PVDC resin composition according to the present invention may be applied in the form of a stretched film, thereby providing a heat shrink film having excellent metallic luster.

8. Manufacturing method of stretched film :

The stretched film formed from the PVDC resin composition according to the present invention may be suitably prepared according to the production method comprising each of the following steps (I) to (V):

(I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A);

(II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers;

(III) adding to the powder resin the total amount of additive (B) which is liquid at room temperature, or the residual amount of additive (B) which is liquid at room temperature which was used as necessary in step (I);

(IV) adding flaky inorganic powder (D) to said powder resin; And

(V) preparing a stretched film using the compound obtained through each step.

At least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C) is added in at least one of steps (I) to (III).

The steps (I) to (IV) are carried out under the same conditions as in the method for producing the PVDC resin composition. In step (I), it is preferred to synthesize a powder resin of a PVDC resin containing at least one additive (B) which is liquid at room temperature, selected from the group consisting of epoxy compounds and plasticizers. At the time of polymerization, it is more preferable that both the epoxy compound and the plasticizer are contained in the powder resin of the PVDC resin.

In step (II), epoxy group containing resins, lubricants, fillers or mixtures thereof are added. In step (III), the residual amount of the epoxy compound and / or plasticizer is added. However, all of these are preferably added.

The total amount of the additive which is liquid at room temperature can be used in step (I) or (III). However, it can be used partly in each step. In this case, the ratio (weight ratio) of the liquid additive added between steps (I) and (III) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, particularly preferably Is intended to be 30:70 to 70:30. By adding the liquid additive in step (III), the dispersibility of the flaky inorganic powder can be remarkably improved, and the discoloration and blackening of the flaky inorganic powder can be prevented.

In step (IV), the flaky inorganic powder is added to prepare a powdery resin composition (compound). Therefore, in the above steps (II) to (IV), temperature conditions are adopted in which the powder resin of the PVDC resin maintains the form of the powder. The preparation of the compound can be carried out by mixing the individual components using a blender such as a blade blender, ribbon blender or Henschel mixer.

In step (IV), an organic pigment can be added together with the flaky inorganic powder. In addition to the addition of the organic pigment to the powdered resin in step (IV), the organic pigment is a glycidyl group-containing (meth) acrylic resin composition containing an organic pigment as an epoxy group-containing resin in step (III). Can be added by use. After step (IV), the step of further adding ethylene-vinyl acetate copolymer (F) may be arranged.

In step (V), the stretched film can be formed by using the compound. Prior to stretching, the compound may be sieved to remove aggregated coarse particles. As a method of forming the stretched film, for example, according to a method known per se in the art, it is suitable to apply a blow-film extrusion method using a circular die.

Stretching is performed at least in the uniaxial direction. However, biaxial stretching is preferably performed. Since a biaxially oriented film shows good heat shrinkability, it is suitable for use as a heat shrinkable packaging material. The biaxially oriented film is suitable for use as a retorting heat resistant film. When biaxial stretching is performed, the stretching ratio is preferably 2 to 5 times in the longitudinal direction (MD) and 2 to 5 times in the transverse direction (TD). When the draw ratio in the transverse direction TD is higher than the draw ratio in the longitudinal direction MD, the resulting film is easy to be stretched. When the stretched film is used as a packaging material, the film may be heat shrinked so as to fit tightly to a packaging material such as a processed food and exhibit a vivid metallic luster.

The thickness of the stretched film as a single layer film is generally 5 to 50 µm, preferably 10 to 30 µm. The stretched film is also used as a double film depending on its use.

9. Stretched film :

The stretched film according to the present invention is a stretched film formed from a PVDC resin composition containing flaky inorganic powder. In the stretched film according to the present invention, the content of flaky inorganic powder is 0.03 to 4 parts by weight per 100 parts by weight of polyvinylidene chloride resin. The stretched film according to the invention preferably has the following properties:

(1) The stretched film which concerns on this invention has a reflectance of 10 or more, Preferably it is 15 or more. Higher reflectance of the film indicates higher metallic luster. In many cases, the reflectance is about 20 to about 55. The upper limit of the reflectance is generally about 60.

(2) The stretched film which concerns on this invention has a haze value of 8 or more, Preferably it is 10 or more. Higher haze values of the film indicate higher masking rates. The upper limit of the haze value is generally about 95%. In many cases, the haze value is between 15 and 90%.

(3) When the stretched film which concerns on this invention is immersed in hot water of 100 degreeC for 3 minutes, it is preferable to have 10% or more shrinkage in at least one direction. When the stretched film according to the invention is a biaxially stretched film, the heat shrinkage in the longitudinal direction (MD) is preferably 20 to 30%, while the heat shrinkage in the transverse direction (TD) is 15 to 25%. Since the heat shrinkage of the stretched film according to the present invention is moderately high, it can be firmly fit into the packaging material when used as the packaging material, thereby providing a product having excellent metallic luster.

(4) In the stretched film according to the present invention, flaky inorganic powder, such as flaky aluminum powder, has a diameter in the range of 1 to 50 µm, preferably 1 to 35 µm, when observed with a scanning electron microscope (SEM) photograph. It is preferable to disperse | distribute as microparticles | fine-particles which have. According to the production method of the present invention, the flaky inorganic powder is finely ground in the preparation or processing of the compound. By finely pulverizing the flaky inorganic powder, when a small amount of the flaky inorganic powder is uniformly dispersed in the PVDC resin composition, a stretched film having excellent metallic luster and high maskability can be provided.

(5) The stretched film according to the present invention generally exhibits metallic luster with silver hue when flaky inorganic powder such as flaky aluminum powder is contained. An organic pigment is contained together with flaky inorganic powder. In this case, a stretched film having a metallic luster of another desired color tone other than silver color tone may be provided. When red organic pigments and / or yellow organic pigments are used, a stretched film having a golden metallic luster can be provided. The organic pigment is generally used at a ratio of 0.001 to 3 parts by weight per 100 parts by weight of PVDC resin.

(6) The stretched film according to the present invention has excellent gas barrier properties as measured by an oxygen transmission rate of about 10 to 25 cm ³ / m ² · 24hr · atm as measured at 23 ° C in accordance with ASTM 3985.

The stretched film according to the present invention contains at least one epoxy heat stabilizer selected from epoxy compounds which are liquid at room temperature and epoxy group-containing resins which are solid at room temperature in a proportion of 0.05 to 6 parts by weight per 100 parts by weight of polyvinylidene chloride resin. It is desirable to.

The stretched film according to the present invention is suitable for use as a packaging material for processed foods such as fish meat sausages and processed meat products, which are single or multilayer films. Since the flaky inorganic powder can be used in combination with an organic pigment, a packaging material excellent in metallic luster of another desired color tone other than silver can be provided.

The stretched film is formed by overlapping two films with each other after blown film extrusion to form a double film, slitting both ends of the film, and sealing these parts while forming a cylindrical shape by a packaging machine, It is mainly used as a packaging material to obtain a packaged product by filling the contents therein and then gripping the sock end. The stretched film is suitable for use as a packaging material for processed foods such as fish meat sausages and processed meat products.

Example

Hereinafter, the present invention will be described in more detail by the following examples and comparative examples. However, the present invention is not limited to these examples. The evaluation method used in the present invention is as follows:

(1) reduced viscosity:

After extracting the PVDC resin by Soxhlet extractor using methanol as the solvent, the extract was dried to provide a sample. The reduced viscosity of the sample was measured using a Ubbellohde viscometer under the condition that cyclohexane was used as the solvent, the resin concentration was 4 g / l, and the measurement temperature was 30 ° C. The reduced viscosity is an index for the degree of polymerization of the PVDC resin, indicating that the higher the reduced viscosity value, the higher the degree of polymerization.

(2) Extrudeability:

The resin composition (compound) was melt-extruded using the extruder which has a screw diameter of 40 mm. Its extrusion state was observed and its extrudability was evaluated based on the following criteria:

: Variations in motor load and extrusion output are small, and extrusion can be performed stably;

(Triangle | delta): The change of a motor load and an extrusion output is unstable.

(3) elongation:

The parison obtained by melt extruding the sample in tubular form was quenched with cold water and then preheated by immersion in water at room temperature. Next, the parison was biaxially stretched 3.0 times in the longitudinal direction and 4.5 times in the transverse direction by the blowing-film extrusion method. The biaxially oriented film thus obtained was folded, relaxed to several% and wound with a winder. Elongation was evaluated according to the following criteria:

: Stable stretching processing could be performed without stretching nonuniformity and color tone nonuniformity.

X: Fish eye like agglomerates of pigment generate | occur | produced in large quantities, and stable extending | stretching process was difficult.

(4) metal luster:

The film sample was placed on the desk and visually evaluated for its metallic luster. Metal luster was judged by evaluation by seven people. Evaluation criteria were as follows:

: Excellent mask property and clear metallic luster.

(Triangle | delta): Although maskability is rather bad, metal gloss still has no problem practically.

X: A lack of metallic luster, the film surface is rough, and lack of sharpness.

(5) reflectance (700 nm):

Using a spectrophotometer (type COLORCOM C, manufactured by Dainichi Chemical Industry Co., Ltd.), the L value (n = 5) of the film sample cut into 5 mm rectangles was measured according to the black pack reflection method. Its average value was observed. Higher reflectance indicates that the film has a higher metallic luster.

(6) Haze value (%):

Using a turbidimeter (NDH-300A type, manufactured by Nippon Denshoku Kogyo K.K.), the haze value of the film sample cut into 5 mm rectangles was measured (average value of n = 5). Higher haze values indicate higher maskability.

(7) delamination:

After the 10 cm long scotch tape was pasted in the machine direction of the film sample, the scotch tape was peeled off from the film sample. At this time, the peeled state of the film sample surface was observed and the thin film peeling of the said film was evaluated in accordance with the following reference | standard. Films that are susceptible to delamination are difficult to become films with a vivid metallic luster:

: Even when peeling off the tape, the film did not delaminate;

Δ: when peeling off the tape, the thin layer on the film surface was partially peeled off;

X: When peeling off a tape, the whole thin layer on the film surface peeled.

(8) hydrothermal shrinkage:

The film sample was immersed in hot water at 100 ° C. for 3 minutes and then taken from the hot water to measure film shrinkage in the longitudinal direction (MD) and the transverse direction (TD), respectively.

Example 1

(1) Preparation of the compound :

Powder resin of PVDC (2) [vinylidene chloride (VD) / vinyl chloride (VC) = 88/12 (% by weight), reduced viscosity = 0.058]) was used as the PVDC resin. In order to obtain the ratio, in preparing the powdered resin, 0.3 parts by weight of epoxidized linseed oil (O-180) and 3.5 parts by weight of dibutyl sebacate were contained in 100 parts by weight of the PVDC resin.

The powder resin was added to the blender, 0.15 parts by weight of lubricant (calcium montanate) was added as an additive that was solid at room temperature, and then 1.7 parts by weight of epoxidized linseed oil was added as an additive that was liquid at room temperature. Thereafter, while heating and stirring the mixture, 0.8 part by weight of flaky aluminum powder [average particle diameter: 14 μm, the ratio (a) of the dimension (a) to the planar direction with respect to the dimension (b) of the thickness direction of each particle (a) / b) = about 36, surface treated with stearic acid]. While mixing the respective components, the resulting mixture was heated to 85 ° C. and then the mixture was cooled. The mixture was then sieved through a 10 mesh sieve and the aggregated molecules were removed. The amount of each component added is shown in Table 1. As other additives, Igranox 245, distearyl thiodipropionate and sorbitan fatty acid esters were used in ratios of 0.02 parts by weight, 0.01 parts by weight and 0.1 parts by weight, respectively, per 100 parts by weight of the PVDC resin.

(2) Preparation of the stretched film :

Compounds prepared as described above were melt extruded in tubular form using a vacuum hopper and a 90 mm diameter extruder (vacuum pressure: adjusted to about -680 mmHg) and quenched in a cooling bath. The extrudate is then passed through a hot water bath and expanded by introducing air under pressure between two pairs of pinch rollers having different rotational surface speeds, thereby expanding the extrudate 2.5 times in the longitudinal direction and in the transverse direction. The stretched film was produced by biaxial stretching at a draw ratio of 4.2 times. The evaluation results thereof are shown in Table 1.

Example 2

As PVDC resin, instead of PVDC resin (2), 85 parts by weight of PVDC (1) [VD / VC = 88/12 (% by weight), reduced viscosity = 0.063] and 15 parts by weight of PVDC (3) [VD / VC = 83 / 17 (% by weight), reduced viscosity = 0.052] A compound was prepared in the same manner as in Example 1 except that each powder resin (100 parts by weight in total) was used, and a biaxially oriented film was prepared. The results are shown in Table 1.

Example 3

As an additive that is solid at room temperature, instead of 0.15 parts by weight of lubricant, 1 part by weight of glycidyl group-containing (meth) acrylic resin [GMA: glycidyl methacrylate methyl methacrylate-styrene-butyl acrylate (30/31 / 31/8% by weight) tetramer], except that the compound was prepared in the same manner as in Example 1, and the content of the epoxidized linseed oil added at the time of blending was changed from 1.7 parts by weight to 0.7 parts by weight, A biaxially oriented film was produced. The results are shown in Table 1.

Example 4

A compound was prepared in the same manner as in Example 1, except that a filler (calcium carbonate) was used instead of the lubricant as an additive that was solid at room temperature, to prepare a biaxially stretched film. The results are shown in Table 1.

Comparative Example 1

A compound was prepared in the same manner as in Example 1 except that the amount of flaky aluminum powder used was changed from 0.8 part by weight to 0.01 part by weight, to prepare a biaxially stretched film. The results are shown in Table 1.

Comparative Example 2

A compound was prepared in the same manner as in Example 1 except that the amount of flaky aluminum powder used was changed from 0.8 part by weight to 5 parts by weight, to prepare a biaxially stretched film. The results are shown in Table 1.

Composition (part by weight) Example Comparative example One 2 3 4 One 2 PVDC (1) - 85 - - - - PVDC (2) 100 - 100 100 100 100 PVDC (3) - 15 - - - - Epoxylated Flax Seed Udibutyl Sebacate Liquid Additives 0.33.5 0.33.5 0.33.5 0.33.5 0.33.5 0.33.5 Solid Additive GMA Lubricant Filler -0.15- -0.15- One-- --0.15 -0.15- -0.15- Liquid additives (when blended) Epoxylated linseed oil 1.7 1.7 0.7 1.7 1.7 1.7 Scaly aluminum powder 0.8 0.8 0.8 0.8 0.01 5 Organic Pigment (Red / Yellow) - - - - - - Spherical aluminum powder - - - - - - EVA - - - - - - Extrudability △ Extensibility ◎ × Metal polished × reflectivity 43 42 43 42 14 54 Haze value (%) 63 62 63 61 5 90 Delamination × Hydrothermal shrinkage (100 ° C / 3 minutes) MD (%) TD (%) 2316 2218 2417 2217 2519 - (Note) In Table 1, the indication "-" of the hydrothermal shrinkage of Comparative Example 2 indicates that the stretchability of the resin composition was poor and no measurement was performed.

Example 5

The amount of flaky aluminum powder used was changed from 0.8 part by weight to 0.4 part by weight, except that 0.026 part by weight of red organic pigment and 0.36 part by weight of yellow organic pigment were added when the flaky aluminum powder was added. A compound was prepared in the same manner as in Example 1, and a biaxially oriented film was prepared. The results are shown in Table 2.

Example 6

The amount of flaky aluminum powder used in Example 1 was changed from 0.8 parts by weight to 0.5 parts by weight. After heating to 85 ° C. with mixing of the respective components, the resulting mixture was cooled and 2.5 parts by weight of ethylene-vinyl acetate copolymer (EVA; vinyl acetate content: 20% by weight) was added. The resulting mixture was sieved through a 10 mesh sieve to remove aggregated granules. Thereafter, a biaxially stretched film was produced in the same manner as in Example 1. The results are shown in Table 2.

Example 7

Example except for using an organic pigment-containing GMA compound [GMA: red organic pigment: yellow organic pigment = 1: 0.026: 0.36 (weight ratio)] instead of glycidyl group-containing (meth) acrylic resin (GMA) A biaxially oriented film was prepared in a similar manner to 3. The results are shown in Table 2.

Comparative Example 3

A compound was prepared in the same manner as in Example 1, except that spherical aluminum powder (average particle diameter = about 40 μm) was used instead of flaky aluminum powder as the metal powder. The results are shown in Table 2.

[Comparative Example 4]

In the same manner as in Example 1, except that the amount of epoxidized linseed oil added was changed from 2.0 parts by weight to 0.03 parts by weight in total, and the amount of added dibutyl sebacate was changed from 3.5 parts by weight to 5 parts by weight. The compound was produced and the biaxially stretched film was produced. The results are shown in Table 2.

[Comparative Example 5]

In the same manner as in Example 4, except that the amount of epoxidized linseed oil added was changed from 2.0 parts by weight to 0.03 parts by weight in total, and the amount of added dibutyl sebacate was changed from 3.5 parts by weight to 5 parts by weight. The compound was produced and the biaxially stretched film was produced. The results are shown in Table 2.

Composition (part by weight) Example Comparative example 5 6 7 3 4 5 PVDC (1) - - - - - - PVDC (2) 100 100 100 100 100 100 PVDC (3) - - - - - - Epoxylated Flax Seed Udibutyl Sebacate Liquid Additives 0.33.5 0.33.5 0.33.5 0.33.5 0.015 0.015 Solid Additive GMA Lubricant Filler -0.15- -0.15- One-- -0.15- -0.15- --0.15 Liquid additives (when blended) Epoxylated linseed oil 1.7 1.7 0.7 1.7 0.02 0.02 Scaly aluminum powder 0.4 0.5 0.8 - 0.8 0.8 Organic Pigment (Red / Yellow) 0.026 / 0.36 - 0.026 / 0.36 - - - Spherical aluminum powder - - - 0.8 - - EVA - 2.5 - - - - Extrudability × × Extensibility - - Metal polished × - - reflectivity 37 47 41 15 - Haze value (%) 36 56 61 6 - - Delamination - - Hydrothermal shrinkage (100 ° C / 3 minutes) MD (%) TD (%) 2217 2419 2117 2116 - - (Note) (1) The indication "-" of Comparative Examples 4 and 5 indicates that the elongation of each resin composition was poor and no measurement was performed. (2) The organic pigment-containing GMA composition was obtained in Example 7. Was used.

According to the present invention, there is provided a polyvinylidene chloride resin composition containing flaky inorganic powder and excellent in melt processability, stretch processability, thermal stability, color tone, and the like, and a production method thereof. According to the present invention, further, using the polyvinylidene chloride resin composition excellent in melt processability or the like, a stretched film excellent in metallic luster is provided.

According to the present invention, a method for producing a stretched film having excellent metallic luster using a polyvinylidene chloride resin is provided. The stretched film according to the present invention is suitable for use as a packaging material for processed foods such as beef sausage and processed meat products because it has a metallic luster of clear color, heat shrinkability and excellent gas barrier properties.

Claims (27)

Polyvinylidene chloride resin composition containing: (A) polyvinylidene chloride resin, (B) at least one additive which is liquid at room temperature, selected from the group consisting of epoxy compounds and plasticizers, (C) at least one additive which is solid at room temperature selected from the group consisting of epoxy group-containing resins, lubricants and fillers, and (D) flaky inorganic powder [here, The content of flaky inorganic powder (D) is 0.03 to 4 parts by weight per 100 parts by weight of the polyvinylidene chloride resin, At least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C) is contained at a ratio of 0.05 to 6 parts by weight per 100 parts by weight of the polyvinylidene chloride resin] . The polyvinylidene chloride resin composition according to claim 1, wherein the polyvinylidene chloride resin (A) is composed of a combination of two or more polyvinylidene chloride resins having different reducing viscosities. The polyvinylidene chloride resin composition according to claim 1, wherein the flaky inorganic powder (D) is flaky aluminum powder. The polyvinylidene chloride resin composition according to claim 1, which further contains an organic pigment (E). The polyvinylidene chloride resin composition according to claim 4, wherein the organic pigment (E) consists of a combination of a red inorganic pigment and a yellow inorganic pigment. The polyvinylidene chloride resin composition according to claim 1, further comprising ethylene-vinyl acetate copolymer (F) in a proportion of 0.5 to 5 parts by weight per 100 parts by weight of polyvinylidene chloride resin. The polyvinylidene chloride according to claim 1, wherein the polyvinylidene chloride resin (A) is a powder resin having a resin particle size in the range of 40 to 600 µm, and the polyvinylidene chloride resin composition is in the form of a compound. Chloride resin composition. A stretched film formed from the polyvinylidene chloride resin composition according to any one of claims 1 to 7. A stretched film formed from a polyvinylidene chloride resin composition, wherein the film is characterized by the following (1) to (3): (1) the polyvinylidene chloride resin composition contains flaky inorganic powder in a ratio of 0.03 to 4 parts by weight per 100 parts by weight of polyvinylidene chloride resin, (2) the reflectance of the film is 10 or more, (3) The haze value of the said film is 8% or more. 10. The stretched film of claim 9, wherein the polyvinylidene chloride resin composition is a polyvinylidene chloride resin composition containing: (A) polyvinylidene chloride resin, (B) at least one additive which is liquid at room temperature, selected from the group consisting of epoxy compounds and plasticizers, (C) at least one additive which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers, and (D) flaky inorganic powder [Here, at least one epoxy heat stabilizer selected from the group consisting of an epoxy compound in component (B) and an epoxy group-containing resin in component (C) is contained at a ratio of 0.05 to 6 parts by weight per 100 parts by weight of polyvinylidene chloride resin. being]. 10. The stretched film according to claim 9, wherein the film is a heat shrinkable film having a shrinkage rate in at least one direction of 10% or more when immersed in hot water at 100 ° C for 3 minutes. 10. The stretched film according to claim 9, wherein the flaky inorganic powder is flaky aluminum powder. The stretched film according to claim 9, wherein the thickness is in the range of 5 to 50 µm. A process for producing a polyvinylidene chloride resin composition, comprising the following steps (I) to (IV): (I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A); (II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers; (III) adding to the powder resin the total amount of the additive (B) which is liquid at room temperature, or the remaining amount of the additive (B) which is liquid at room temperature which was used as necessary in step (I); (IV) adding flaky inorganic powder (D) to the powdered resin Wherein at least one epoxy heat stabilizer selected from the group consisting of epoxy compounds in component (B) and epoxy group containing resins in component (C) is added in at least one of steps (I) to (III). The method of claim 14, wherein in step (I), the powder resin of the polyvinylidene chloride resin (A) is copolymerized with a monomer copolymerizable with vinylidene chloride in the presence of at least one additive (B) which is liquid at room temperature. The manufacturing method characterized by the above-mentioned. The process according to claim 14, wherein in step (IV), the organic pigment (E) is added together with the flaky inorganic powder (D). The production method according to claim 14, wherein in step (III), an epoxy group-containing resin composition containing an organic pigment as an epoxy group-containing resin is added. 15. The process according to claim 14, wherein in step (IV), flaky aluminum powder is added as flaky inorganic powder (D). The process according to claim 14, further comprising, after step (IV), further adding ethylene-vinyl acetate copolymer (F). A process for producing a stretched film made of a polyvinylidene chloride resin composition, characterized by comprising a series of the following steps (I) to (V): (I) copolymerizing vinylidene chloride with a monomer copolymerizable therewith and performing the copolymerization in the presence of at least one additive (B) which is liquid at room temperature, selected from the group consisting of an epoxy compound and a plasticizer, if necessary, Also, if necessary, after the copolymerization, by adding at least one additive (B) which is liquid at room temperature, preparing a powder resin of the polyvinylidene chloride resin (A); (II) adding to the powder resin at least one additive (C) which is solid at room temperature, selected from the group consisting of epoxy group-containing resins, lubricants and fillers; (III) adding to the powder resin the total amount of the additive (B) which is liquid at room temperature, or the remaining amount of the additive (B) which is liquid at room temperature which was used as necessary in step (I); (IV) adding flaky inorganic powder (D) to said powder resin; And (V) preparing a stretched film using the compound obtained through each step Wherein at least one epoxy heat stabilizer selected from the group consisting of epoxy compounds in component (B) and epoxy group containing resins in component (C) is added in at least one of steps (I) to (III). 21. The method of claim 20, wherein in step (I), the powder resin of the polyvinylidene chloride resin (A) is copolymerized with monomers copolymerizable with vinylidene chloride in the presence of at least one additive (B) which is liquid at room temperature. The manufacturing method characterized by the above-mentioned. The production process according to claim 20, wherein in step (IV), an organic pigment (E) is added together with the flaky inorganic powder (D). The production process according to claim 20, wherein in step (III), an epoxy group-containing resin composition containing an organic pigment as an epoxy group-containing resin is added. 21. The method according to claim 20, wherein in step (V), biaxial stretching is performed with a stretching ratio of 2 to 5 times in the longitudinal direction (MD) and 2 to 5 times in the transverse direction (TD). The production process according to claim 20, wherein in step (IV), flaky aluminum powder is added as flaky inorganic powder (D). The process according to claim 20, further comprising adding ethylene-vinyl acetate copolymer (F) after step (IV) but before step (V). The production process according to claim 20, wherein in step (V), a stretched film having a reflectance of 10 or more and a haze value of 8% or more is obtained.