JPH10101878A - Vinylidene chloride-based resin composition and molded product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition improving a characteristics relating to secondary processing properties such as a puncture of a film in performing a retort sterilization of a fish meat, a raw meat, etc., excellent in yield property and suitable for a casing, etc., by containing a specific acrylic resin and a vinylidene chloride-based resin. SOLUTION: This vinylidene chloride-based composition consists of (A) 0.05-10 pt.wt. linear and multiple stage polymerized acrylic resin containing a polymer having at least one <=(-) 40 deg.C glass transition point and 250,000-1,000,000, preferably 250,000-400,000 weight averaged molecular weight and consisting of an acrylic acid ester as a main component, and (B) 100 pts.wt. vinylidene chloride- based resin. Further, a film or a casing having a heat shrinking property is obtained from the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vinylidene chloride resin composition and a molded product thereof. Specifically, fish meat,
When performing raw retort sterilization of raw meat and the like, a vinylidene chloride resin composition containing an acrylic resin (processing aid) that improves secondary processing characteristics such as bursting, and a vinylidene chloride resin product formed therefrom, In particular, it relates to film and casing.

[0002]

2. Description of the Related Art As is well known, vinylidene chloride resin is
Due to its high oxygen barrier properties, moisture proofness, flame retardancy, chemical resistance, etc., it is extruded into food packaging films, containers, fibers for doll hair, etc. and used. Particularly in the field of food packaging films, (tubular) vinylidene chloride-based resin films and casings are useful because fish meat, raw meat and the like can be retort-sterilized to produce products that can be stored for a long period of time. The retort sterilization is usually performed by a heat treatment at 120 ° C. for about 20 minutes. During this heat treatment, the film may rupture due to expansion of the contents, which is a factor of lowering the product yield.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a vinylidene chloride resin composition having improved properties relating to secondary workability such as rupture of a film when performing retort sterilization of fish meat, raw meat and the like, and a molding thereof. It is to provide things.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, blended a specific amount of an acrylic resin (processing aid) having a specific composition and molecular weight with a vinylidene chloride resin. As a result, it has been found that a film made of a vinylidene chloride-based resin composition with little rupture of the film can be obtained when performing retort sterilization treatment of fish meat, raw meat, and the like, and completed the present invention.

That is, a first aspect of the present invention is a vinylidene chloride-based resin comprising an acrylic resin having at least one glass transition temperature of -40 ° C. or lower and a weight average molecular weight of 250,000 to 1,000,000, and a vinylidene chloride resin. An object of the present invention is to provide a resin composition, a molded product thereof, and a film, a casing, and the like in which the molded product has heat shrinkability.

A second aspect of the present invention is to provide a polymer (A) having an acrylic ester as a main component and having a weight average molecular weight of more than 60,000 and about 150,000 or less, and a polymer (A) in the presence of the polymer (A). The weight average molecular weight obtained by polymerizing a methacrylate monomer or monomer mixture (B) is 400,000 to 1
Provided is a vinylidene chloride-based resin composition composed of an acrylic resin and vinylidene chloride-based resin, which is 100,000.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
A first aspect of the present invention is that at least one glass transition temperature (Tg)
Is -40 ° C or less and the weight average molecular weight is 250,000 to 100
The present invention relates to a vinylidene chloride resin composition comprising an acrylic resin and a vinylidene chloride resin. The acrylic resin has at least one glass transition temperature of −40 ° C. or lower and a weight average molecular weight of 250,000 to 1,000,000.
If the weight average molecular weight is less than 250,000, retort suitability is poor. If it exceeds 1,000,000, so-called extrusion processability such as fluctuations in extrusion behavior due to poor dispersion and poor appearance of the extrudate due to high molecular weight tends to deteriorate. Further, considering the dispersibility with a vinylidene chloride resin having a wider average molecular weight, 250,000 to
Less than 400,000 is preferred. The most preferable range in these balances is from 300,000 to less than 400,000.

The acrylic resin in the case of a multi-stage polymer contains a polymer (A) containing an acrylate ester as a main component as a core (called a core phase), and further has an outer shell (hereinafter referred to as a shell) of the core phase. A phase obtained by polymerization of a methacrylate monomer or a monomer mixture (B) in the presence of (A) is preferable. Here, the polymer (A) preferably has at least one glass transition temperature of -40C or lower, more preferably -50C or lower.

The shell phase is 80 to 80% of the whole acrylic resin.
20% by mass is preferred. If the shell phase is too small, it is insufficient to achieve the purpose of preventing the rupture of the film. If the shell phase is too large, the dispersion becomes poor at the time of melting, causing fish eyes.

The polymer (A) mainly composed of an acrylate ester is preferably polymerized from a monomer system containing at least 70% by mass of the acrylate ester. The acrylate can be selected from the group of, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, and the like. The ester has 1 to 18 carbon atoms in the alkyl group. Are preferred. As the polymerization partner of the acrylate, if necessary, at least one vinyl selected from the group consisting of methacrylate, methacrylate having a polyorganosiloxane group in a side chain, a vinyl aromatic compound and a vinyl cyanide compound Compounds having a monomer can be mentioned. The weight average molecular weight of the polymer (A) is usually preferably 200,000 or less in consideration of the average molecular weight of the whole polymer. More preferably, it is more than 5,000 and not more than 150,000, most preferably from 60,000 to 150,000. If the weight average molecular weight of the polymer (A) is too small, the polymer (A) cannot maintain a solid state at room temperature, the particle shape of the acrylic resin becomes unstable, and the problem of handling during blending occurs. Easy to occur. Further, since the melt viscosity is too low, problems such as poor appearance due to bleeding on the surface of the extrudate are likely to occur. On the other hand, if the molecular weight is too large, the melt viscosity at the time of extrusion of the vinylidene chloride-based resin composition will increase, and the resin temperature will increase due to shearing heat, which will easily promote thermal decomposition degradation.

The glass transition temperature of the polymer (A) is -40 ° C.
In the above case, at the time of extruding the vinylidene chloride-based resin composition, the melt viscosity of the acrylic resin is high, the melt dispersion is likely to be insufficient, the fluctuation of the extrusion behavior due to poor dispersion, the appearance of the extrudate is easily caused, and the like. Not only that, the temperature of the resin rises due to heat generated by shearing, and thermal decomposition and deterioration are easily promoted.

When a methacrylate having a polyorganosiloxane group in the side chain, which is a kind of methacrylate having a glass transition temperature of -40 ° C. or lower, is used, it is necessary to copolymerize with a acrylate or methacrylate. Is preferred. A methacrylate having a polyorganosiloxane group in the side chain is substantially -40;
In order to show a glass transition temperature of not higher than 5 ° C., a weight average molecular weight of 5
It is preferably at least 00. The methacrylic acid ester having a polyorganosiloxane group in the side chain is preferably present in an amount of 1 to 30 parts by mass based on 100 parts by mass of the monomer constituting the acrylic resin. If it exceeds 30 parts by mass,
The lubricity is so strong that it is difficult to obtain workability. For multi-stage polymers,
Although it may be present in the core phase or / and the shell phase (may be plural phases), when it is used for the core phase, even if the weight average molecular weight of the acrylic resin is 250,000 or more, deterioration due to thermal decomposition may occur. This is preferable because it can be more easily prevented.

A preferred shell phase is obtained by polymerizing a methacrylate monomer or mixture (B). The methacrylic acid ester preferably accounts for 80% by mass or more of the shell phase, more preferably 90% by mass or more. If the amount of the methacrylic acid ester is less than 80% by mass of the shell phase, the compatibility with the vinylidene chloride resin is insufficient, and the dispersion is unfavorably caused. Preferred methacrylates have 1 to 18 carbon atoms in the alkyl group, and particularly preferred is methyl methacrylate. The monomer mixture copolymerizable with the methacrylate ester is selected from the group consisting of an acrylate ester, a methacrylate ester having a polyorganosiloxane group in a side chain, a vinyl aromatic compound, a vinyl cyanide compound, vinylidene chloride and vinyl chloride. It is.

The molecular weight of the polymer (A) is controlled by the polymerization temperature,
The amount can be adjusted by the amount of the radical initiator, but if necessary, a chain transfer agent such as an alkyl mercaptan such as n-dodecyl mercaptan and a halide such as carbon tetrachloride may be used in combination.

Polymer (A) constituting acrylic resin
Is difficult to handle when isolated and used because of its low glass transition temperature. Therefore, it is preferable to obtain a multi-stage polymer obtained by polymerizing an alkyl methacrylate or the like in the presence of the polymer (A). It can be confirmed by an electron microscope that the polymer is a multistage polymer. In particular, a two-stage polymer is preferred because it is economical and can provide heat resistance excellent in retort suitability.

The acrylic resin is preferably substantially linear. The substantially linear acrylic resin is
When dissolved in the solvent THF (tetrahydrofuran), it does not produce undissolved substances.

In a second aspect of the present invention, an acrylic resin and a vinylidene chloride resin are used, and the acrylic resin is a multi-stage polymer, and the multi-stage polymer has a weight average molecular weight mainly containing an acrylate ester. Is more than 60,000 and about 150,000 or less, and a weight obtained by polymerizing a methacrylate monomer or a monomer mixture (B) in the presence of the polymer (A). Average molecular weight of 400,000 to 1
The present invention provides a vinylidene chloride-based resin composition having a molecular weight of 100,000. In the present invention, a vinylidene chloride resin composition comprising an acrylic resin and a vinylidene chloride resin which is a multi-stage polymer in which the weight average molecular weight of the acrylic resin and the weight average molecular weight of the polymer (A) constituting the acrylic resin are specified Offer things.

The acrylic resin has a weight average molecular weight of 400,000-
When the weight average molecular weight of the polymer (A) is more than 60,000 and about 150,000 or less, it is difficult to prevent the occurrence of thermal decomposition when added to the vinylidene chloride resin. Is relatively small, such as 0.5 to 3.5% by weight or less. In this case, it is particularly preferable that the reduced viscosity of the vinylidene chloride resin is 0.045 to 0.065 L / g (hereinafter, L / g is omitted).

The acrylic resin used in the present invention may be used together with another acrylic resin having at least one glass transition temperature of -40 ° C. or lower and a weight average molecular weight of less than 20,000 to 100,000.

The outline of the method for producing the acrylic resin of the present invention is as follows. A polymerization vessel charged with a predetermined amount of water, an emulsifier and an emulsion stabilizer is heated to a predetermined temperature (50 ° C.) to obtain a polymer (A).
Is added together with a polymerization catalyst to perform the first-stage polymerization. The polymerization is carried out for a period of time such that the polymerization addition ratio falls within a predetermined range (about 95% or more), and the first-stage polymerization is completed. Then, while maintaining the temperature at the first-stage polymerization temperature, a monomer constituting the polymer (B), a polymerization catalyst and an emulsion stabilizer are added to terminate the reaction at a polymerization addition rate of about 99%, and the reaction system is cooled. The polymerization latex of the reaction product is poured into an aqueous calcium chloride solution to isolate the polymer, washed with water and dried to obtain an acrylic resin.

The acrylic resin is preferably added in an amount of 0.05 to 10 parts by mass based on 100 parts by mass of the vinylidene chloride resin. If the addition amount is small, it is not sufficient to fulfill the function of a film and a casing suitable for retort, and if the addition amount is large, the barrier property of the vinylidene chloride resin tends to be reduced. Usually, the retort suitability is more preferably 0.5 part by mass or more and 3.5 parts by mass or less from the balance with the extrusion processability. The most preferable range in these balances is 0.5 to 2.0 parts by mass.

The vinylidene chloride-based resin in the present invention includes a copolymer of vinylidene chloride and at least one other monomer copolymerizable with vinylidene chloride. The amount of the other monomer in the copolymer is 40 to 2% by mass, and preferably 35 to 4% by mass in view of the balance between the extrudability and the gas barrier property. Other monomers include vinyl chloride, vinyl acetate, vinyl propionate, alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, acrylonitrile, methacrylonitrile, acrylamide, vinylalkyl Includes ethers, vinyl alkyl ketones, acrolein, allyl esters and ethers, butadiene, chloroprene. It may be a ternary, quaternary or higher copolymer. The vinylidene chloride-vinyl chloride copolymer has a wide balance between heat resistance and extrudability, and the addition of the acrylic resin of the present invention makes the retort suitability more effective.

The vinylidene chloride copolymer has a reduced viscosity of 0.1.
038 to 0.075 is preferred. More preferably 0.0
45 to 0.065, and 0. 0 for packages such as retort foods.
055 to 0.065 is more preferred. If the reduced viscosity is too small, the stretching processability, cold resistance, and suitability for the packaging machine will be insufficient. If the reduced viscosity is too large, heat generation and thermal decomposition in the extruder will easily occur, and the fluctuation range of the extruder motor load will be prone. Is large,
Extrusion processability becomes unstable. A mixture of vinylidene chloride copolymers having different reduced viscosities, that is, a mixture of a vinylidene chloride copolymer having a reduced viscosity of 0.048 or more and a vinylidene chloride copolymer having a reduced viscosity of less than 0.046 may be used. Mixing of a vinylidene chloride copolymer having a reduced viscosity of 0.025 to less than 0.046 is considered from the viewpoint of extrusion processability and cold resistance, and the mixing ratio is preferably 3 to 25% by weight from the balance. The combination with the acrylic resin of the present invention has a more remarkable effect, and is particularly effective for retort use.

In the vinylidene chloride resin composition, in addition to the acrylic resin, known processing aids, plasticizers, stabilizers, lubricants, antiblocking agents, antioxidants, surfactants, light stabilizers, pigments , Fillers and the like. The total amount of the additives is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the vinylidene chloride-based resin. For example, an ethylene copolymer, that is, vinyl acetate, (meth) acrylic acid, and an alkyl ester copolymer thereof (particularly, having 1 to 1 carbon atoms)
At least one selected from alkyl esters having four) or MBS resins. The ethylene content of the ethylene copolymer includes 65 to 85% by mass, more preferably 75 to 80% by mass. The ethylene content is preferably 85% by mass or less in order to maintain the transparency of the molded product, especially the film. On the other hand, it prevents powder blocking, prevents powder from biting into the screw during extrusion processing, reduces fluctuations in the motor load of the extruder and fluctuations in the extrusion amount, and reduces gas barrier properties (both vinylidene chloride and vinylidene chloride). (In the case of a polymer), the ethylene content is preferably at least 65% by mass so as not to decrease the content. Usually, the mixing amount is preferably from 0.3 to 5 parts by mass. Furthermore, in order to improve the fluidity of the powder or to increase the compatibility with the chlorine-based resin, the ethylene content is 65 to 65.
A small amount of an ethylene copolymer other than 85% by mass can be added. Melt viscosity of ethylene copolymer is melt processability,
From the viewpoint of gas barrier properties, a melt index (MI) of 3 or more is preferable. It is more preferable that the melt viscosity is smaller than the melt viscosity of the chlorine-based resin in view of melt processability.

In addition, specifically, dioctyl phthalate
Acetyl tributyl citrate, dibutyl sebacate, dioctyl sebacate, diisobutyl adipate
Acetylated monoglycerides, plasticizers such as adipic acid-based polyesters (weight average molecular weight of 1,000 to 4,000), epoxidized oils such as soybean oil and linseed oil, and epoxy group-containing resins, magnesium hydroxide, magnesium oxide, calcium hydroxyphospho -Inorganic bases such as sodium pyrophosphate, disodium dihydrogen pyrophosphate and sodium monophosphate; stabilizers such as ethylenediaminetetraacetate; polyolefin oxide such as polyethylene oxide; paraffin wax; polyethylene wax; montanic acid ester wax Waxes, fatty acid esters such as glycerin monoester, lubricants such as mono- and bisamide derivatives of fatty acids, triethylene glycol bis-3-
(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate (for example, Iba
RGANOX 245), octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, α,
β, γ, δ various tocophenols and mixtures thereof, antioxidants such as butylhydroxytoluene, thiodipropionic acid alkyl esters having an alkyl group of 12 to 18 carbon atoms (for example, dilauryl thiodipropionate) And distearyl thiodipropionate). Surfactants such as sorbitan fatty acid ester type and polyoxyethylene sorbitan fatty acid ester type.

Particularly preferred examples of the vinylidene chloride resin include ethylenediaminetetraacetic acid or a salt thereof, at least one salt of a non-alkene weak acid (particularly, a phosphate or a derivative thereof), and if necessary, triethyleneglycolbis-3. -(3-tert-butyl-4-hydroxy-5
-Vinylidene chloride is polymerized in the presence of an auxiliary selected from the group of -methylphenyl) propionate, vitamin E, alkyl thiodipropionate. A preferable range of the addition amount is 0.0005 to 0.25 parts by weight of ethylenediaminetetraacetic acid or a salt thereof and 0.0001 to 0.115 parts by weight of at least one salt of a non-alkene weak acid.
If necessary, triethylene glycol bis-3- (3-
(Tert-butyl-4-hydroxy-5-methylphenyl) propionate 0.0005-0.55 parts by weight, vitamin E 0.0005-0.2 parts by weight, alkyl thiodipropionate 0.0005-0.2 The vinylidene chloride is polymerized in the presence of an auxiliary selected from the group of parts by weight. It is particularly effective for improving color tone.

Some of these additives may be added during the polymerization, or may be mixed in a powder form. The additives are adsorbed or absorbed by the ethylene copolymer, MBS resin, and acrylic processing aid, and a good balance between extrudability and gas barrier properties can be obtained together with a synergistic effect of mixing with the vinylidene chloride resin. Additives other than plasticizers and stabilizers are used as needed.

As the pigment, titanium oxide pigment 0.10 to 0.10
10 parts by weight. Titanium oxide pigments
The vinylidene chloride-based resin has an effect of preventing discoloration of food contents due to ultraviolet rays, while increasing adhesion and decomposition at a die outlet. However, when a vacuum hopper or the like is used, adhesion and decomposition are effectively reduced, and a large amount of 0.10 to 10 parts by weight can be added.

The vinylidene chloride-based resin is close to the thermal decomposition temperature of the vinylidene chloride-based resin and the extrusion temperature, and it is difficult to improve the thermal stability of the resin. Therefore, a method of suppressing heat generation of the resin is often adopted. For example, it is conceivable to reduce the degree of polymerization or add more additives. In the former, the strength of the vinylidene chloride copolymer decreases, and the vinylidene chloride copolymer tends to be broken when a film tension is applied for elongating the film wrinkles during packaging, so that the suitability of the packaging machine is deteriorated and the cold resistance is also reduced. In the latter, the gas barrier properties are reduced. Extrudability is closely related to suitability for packaging machines. If the extrusion processability is poor, the fluctuation of the extrusion motor load becomes large, and unevenness of the extrusion amount occurs. This causes unevenness in the film thickness,
The energy per unit thickness applied to the film during sealing varies. If the film is too thin, the film will melt and the pinhole will break, and if the film is too thick, there will be a problem that the seal will not stick.
When the decomposed product flows out, the decomposed product causes the seal electrode to spark and the film breaks into small pieces to form a pinhole. The adhered decomposition products at the die outlet become minute spots in the width direction of the film thickness, which cause minute wrinkles of the film and cause sealing failure. These factors cause a decrease in retort suitability, but can be improved by adding the acrylic resin of the present invention.

When the vinylidene chloride-based resin is a mixed system and is the same type of copolymer component, it is easily melted uniformly in the extruder, and the fisheye produced by undesired thermal decomposition, unmelting, etc. of the resin, which is unfavorable in the quality of the formed film. Reduce the occurrence. Further improvement was achieved by the combination of the vinylidene chloride-based resin mixed system and the acrylic resin processing aid of the present invention.

The use of a surface-treated extruder can effectively contribute to the improvement of the extrusion process of these vinylidene chloride resin compositions. With metal surface treatment method, after cleaning metal material mainly composed of iron such as stainless steel,
A heat treatment is performed in an oxidizing atmosphere to form an oxide film, and thereafter, the oxide film is dissolved and removed. Examples of the manufacturing process include mechanical polishing (machine tool polishing, buff polishing) and electrolytic polishing (method for smoothing and glossing the metal surface by an external current based on an electrochemical reaction: metal, October 1988 issue). , 98-104), pre-cleaning (high pressure cleaning, ultrasonic cleaning), ultrapure water cleaning (high temperature ultrapure water cleaning, high purity nitrogen gas drying), heat treatment (oxidation treatment or formation of oxide film: Boshoku Gijutsu, 36, 368-375, 1987 and Boshoku Gijutsu, 419-430, 1987), acid treatment (acid etching treatment or removal of oxide film), post-cleaning (acid solution cleaning, high-pressure ultrapure water cleaning), ultrapure water cleaning ( Washing with high-temperature ultrapure water) and drying (drying with high-purity nitrogen gas), and particularly includes a manufacturing process of heat treatment (forming an oxide film) and acid treatment (removing the oxide film).

Examples of the mixing device include known mixing devices such as a blade blender, a ribbon blender, and a Henschel mixer. Screw feeder in the hopper on the extruder
Mixing can also be performed using a durer or the like. The ethylene copolymer, ie, vinyl acetate, (meth) acrylic acid,
The alkyl ester copolymer (particularly, an alkyl ester having 1 to 4 carbon atoms) and the MBS resin have a temperature of 60 ° C.
It is preferred to mix below.

The obtained vinylidene chloride resin composition is used as a powder or in the form of pellets. For the vinylidene chloride-based resin composition, an extrusion method of supplying the extruder via a vacuum hopper is effective, and the extrudability and color tone are improved.

A recycled resin may be contained in the vinylidene chloride resin composition. A pulverized product containing a vinylidene chloride-based resin can be mixed and recycled.
New ethylene copolymers, namely vinyl acetate, (meth)
Acrylic acid, its alkyl ester copolymer (especially alkyl ester having 1 to 4 carbon atoms) and MBS resin polymer may be mixed, and in particular, a multilayer film containing these, recycling of casing. You may mix things. Extrudability can be improved. In the case of a multilayer, a resin containing recycled material may be disposed as an independent layer.

The vinylidene chloride resin composition of the present invention is melt-molded and, if necessary, stretched to obtain a molded product such as a film, a casing, a sheet and the like. As the molding method, for example, extrusion molding methods such as inflation molding with a circular die, T-die molding, and blow molding can be applied. It is also used as a raw material for laminating. Usually, films and casings obtained by stretching orientation have heat shrinkage and can be retorted. The heat shrinkage of the film and casing is usually about 30 in both length and width.
約 60% (measured at 120 ° C.). Further, the retort is carried out under a normal condition of about 80 to 120 ° C (pressurized 0.01 to 0.30 ° C).
MPa) for 5 minutes to 6 hours. The thickness of the film or casing is preferably about 10 as a single film.
It is about 30 μm, and is also used as a double film.

[0036]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

The weight average molecular weight was measured using a GPC system (manufactured by Shimadzu Corporation). Using THF (tetrahydrofuran) as a developing solvent, a THF solution of the polymer was passed through a GPC column at a constant temperature of 40 ° C., and the elution time was measured with a differential refractometer. The weight average molecular weight was determined using polystyrene, which is a standard sample for GPC column calibration.

The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC20, manufactured by Mettler). Sample approx.
10mg under nitrogen atmosphere from -150 ℃ to 150 ℃ 1
The temperature was raised at 0 ° C. every minute, and the secondary transition start temperature of the calorie was defined as Tg.

The retort puncture test was performed as follows. The kneaded product of livestock meat, lard, corn starch, salt, and water was filled into a tube formed from the above film to obtain a retort package. This is kept at 130 ° C. for 20 minutes (pressure: 0.
25 MPa). 10 per same sample film
0 packages were tested and the puncture rate was calculated from the number of bursts.

(Synthesis Example 1) (1) Polymerization of polymer (A): 58,000 parts by mass of water (hereinafter abbreviated as "parts"), 600 parts of sodium dodecylbenzenesulfonate, tetrasodium pyrophosphate in an autoclave equipped with a stirrer 80 parts, ferrous sulfate heptahydrate 0.5 part, ethylenediaminetetraacetic acid disodium 1.5 part
The temperature was raised to 0 ° C. After the temperature reached 50 ° C., the inside of the autoclave was sufficiently purged with nitrogen gas, and 20,000 parts of BA (butyl acrylate), 200 parts of nOM (n-octyl mercaptan) as input material 1 and 2% tBHP as input material 2
(Tertiary butyl hydroperoxide) 2800 parts of an aqueous solution, and 2800 parts of a 2% Rongalite aqueous solution as an input material 3 were supplied at a fixed amount of 100 from three inlets.
We put in over a minute.

After the completion of charging of Charges 1, 2, and 3, the reaction was continued for 30 minutes. The polymerization conversion was 99%. A part of the reaction mixture was taken out, and the polymer was precipitated by salting out, sufficiently washed with water, and dried at 40 ° C. for 15 hours with a vacuum dryer. The weight average molecular weight of the dried polymer determined by GPC was 62,000 (in terms of polystyrene). Also, DSC
Was -56 ° C.

(2) Two-stage polymer Synthesis of the above (1)
The second stage polymerization was carried out as follows using the polymer (A) polymerized in the above. The inside of the autoclave was sufficiently purged with nitrogen gas, and 19000 parts of MMA (methyl methacrylate) was added as a charge 4 to the autoclave at a constant temperature of 50 ° C.
A 1000 parts, 2% tBHP aqueous solution 50 as input 5
0 parts, 2% Rongalite aqueous solution 5 as input 6
00 parts were introduced from three inlets in a fixed amount over 100 minutes. The reaction was continued for 30 minutes after charging of Charges 4, 5, and 6 was completed. The polymerization conversion was 99%. After completion of the reaction, the mixture is cooled, and the polymer is isolated by throwing the two-stage polymerization latex into an aqueous solution of calcium chloride, washed with water and dried to obtain a two-stage polymer 1.
I got Dried two-stage polymer The weight average molecular weight determined by GPC was 410,000 and Tg was -54 ° C and 95 ° C.

(Synthesis Example 2) In the polymerization of the polymer (A), a 2% tBHP aqueous solution and a 2% Rongalite
The same operation as in Synthesis Example 1 was performed except that the amount of the aqueous solution was changed to 1200 parts, and the two-stage polymer was used. I got 1. Two-stage polymer Has a weight average molecular weight of 210,000 and a Tg of -54.
℃, 95 ℃.

(Synthesis Example 3) (1) Polymerization of polymer (A): 58,000 parts of water, 600 parts of sodium dodecylbenzenesulfonate, 80 parts of tetrasodium pyrophosphate, 0.5 part of ferrous sulfate heptahydrate Then, 1.5 parts of disodium ethylenediaminetetraacetate was heated to 50 ° C. in the same manner as in Synthesis Example 1. BA30000 as input 1
Parts, nOM300 parts, 2% tBHP aqueous solution 4200 parts as input 2, 2% Rongalite as input 3
Using 4,200 parts of an aqueous solution, a polymerization reaction was carried out in the same manner as in Synthesis Example 1. The weight average molecular weight of the polymer (A) was 62,000, and the glass transition temperature was -56 ° C. (2) Two-stage polymer Synthesis of 9500 parts of MMA and 500 parts of BA as input 4 and 250 parts of 2% tBHP aqueous solution as input 5 and 250 parts of 2% Rongalite aqueous solution as input 6 to the reaction system of the above (1). Similarly, the second stage polymerization was performed. 2. two-stage polymer Had a weight average molecular weight of 390,000 and a Tg of -54 ° C and 95 ° C.

Synthesis Example 4 (1) Polymerization of Polymer (A): 58,000 parts of water, 600 parts of sodium dodecylbenzenesulfonate, 80 parts of tetrasodium pyrophosphate, 0.5 part of ferrous sulfate heptahydrate Then, 1.5 parts of disodium ethylenediaminetetraacetate was heated to 50 ° C. in the same manner as in Synthesis Example 1. 4000 parts of BA as input 1
nOM 40 parts, 2% tBHP aqueous solution 55 as input 2
0 parts, 2% Rongalite aqueous solution 5 as input 3
Using 50, a polymerization reaction was carried out in the same manner as in Synthesis Example 1. The weight average molecular weight of the polymer (A) was 62,000, and the glass transition temperature was -56 ° C. (2) Two-stage polymer Synthesis: into the reaction system of (1) above, 34200 parts of MMA and 1800 parts of BA as input 4, 1000 parts of 2% aqueous tBHP as input 5 and input 6
, A 2% Rongalite aqueous solution 1000 was charged, and the second stage polymerization was carried out in the same manner as in Synthesis Example 1. 2. two-stage polymer Had a weight average molecular weight of 610,000. Tg is -5
4 ° C and 95 ° C.

Synthesis Example 5 (1) Polymerization of Polymer (A): 58,000 parts of water, 600 parts of sodium dodecylbenzenesulfonate, 80 parts of tetrasodium pyrophosphate, 0.5 part of ferrous sulfate heptahydrate Then, 1.5 parts of disodium ethylenediaminetetraacetate was heated to 50 ° C. in the same manner as in Synthesis Example 1. BA18000 as input 1
Parts, 2000 parts of SiMA (γ-methacryloxypropyldimethylsiloxypolydimethylsiloxane) (manufactured by Chisso Corporation, Silaplane FM0711), 20 parts of nOM, 2200 parts of a 2% tBHP aqueous solution as input 2, and input 3
The polymerization reaction was carried out in the same manner as in Synthesis Example 1 using 2200 parts of a 2% Rongalite aqueous solution. Polymer (A)
Has a weight average molecular weight of 13,000 and a glass transition temperature of -1.
17 ° C and -56 ° C. (2) Two-stage polymer5. The second stage polymerization was carried out in the same manner as in Synthesis Example 1. Two-stage polymer5. Has a weight average molecular weight of 4
80,000 and Tg were -117 ° C, -54 ° C, and 95 ° C.

Synthesis Example 6 (1) Polymerization of Polymer (A): 58,000 parts of water, 600 parts of sodium dodecylbenzenesulfonate, 80 parts of tetrasodium pyrophosphate, 0.5 part of ferrous sulfate heptahydrate Then, 1.5 parts of disodium ethylenediaminetetraacetate was heated to 50 ° C. in the same manner as in Synthesis Example 1. BA12000 as input 1
Part, ST8000 part, nOM 200 part, 2800 parts of 2% tBHP aqueous solution as input 2, 2% R as input 3
A polymerization reaction was carried out in the same manner as in Synthesis Example 1, except that 2,800 parts of the aqueous solution of ongalite was used. The weight average molecular weight of the polymer (A) was 57,000, and the glass transition temperature was -15 ° C. (2) Two-stage polymer The second stage polymerization was carried out in the same manner as in Synthesis Example 1. Two-stage polymer6. Has a weight average molecular weight of 5
10,000 and Tg were -15 ° C and 95 ° C.

(Synthesis Example 7) (1) Polymerization of Polymer (A): 58,000 parts of water, 600 parts of sodium dodecylbenzenesulfonate, 80 parts of tetrasodium pyrophosphate, 0.5 part of ferrous sulfate heptahydrate Then, 1.5 parts of disodium ethylenediaminetetraacetate was heated to 50 ° C. in the same manner as in Synthesis Example 1. BA 20000 as input 1
A polymerization reaction was carried out in the same manner as in Synthesis Example 1, except that 2,800 parts of a 2% aqueous solution of tBHP were used as input 2, and 2800 parts of a 2% aqueous solution of Rongalite were used as input 3. The weight average molecular weight of the polymer (A) was 350,000, and the glass transition temperature was -56 ° C. (2) Two-stage polymer 7. The second stage polymerization was carried out in the same manner as in Synthesis Example 1. 6. Two-stage polymer Has a weight average molecular weight of 6
80,000 and Tg were -54 ° C and 95 ° C.

Two-stage polymer shown in synthesis example ~ 7. Of 7
Table 1 shows an overview of the properties. In Table 1, the polymer (A) shown in the synthesis example is expressed as a core, and the polymer polymerized in the second stage is expressed as a shell.

[0050]

[Table 1]

(Examples 1 to 11 and Comparative Examples 1 to 4) 2
In order to see the effect on the retort processability by the addition of the step polymer, 100 parts by mass of vinylidene chloride-vinyl chloride copolymer (80% of vinylidene chloride), 4 parts by mass of dibutyl sebacate sebacate as a plasticizer, and a stabilizer As
Formulation A was prepared by adding 1 part by mass of epoxidized linseed oil, and Examples and Comparative Examples are shown below.
Two-stage polymer obtained in Synthesis Example 1 To Formula A above,
Additions of 2, 3 parts by mass were referred to as formulations B-1 (Example 1), B-2 (Example 2), and B-3 (Example 3), respectively. 1. Two-stage polymer obtained in Synthesis Example 2 To Formula A,
As a comparative example, the additions of 2, 3 parts by mass were defined as Formulations C-1 (Comparative Example 1), C-2 (Comparative Example 2), and C-3 (Comparative Example 3). 2. Two-stage polymer obtained in Synthesis Example 3 above. Were added to Formula A by 1, 2, and 3 parts by mass as Formulas D-1, D-2, and D-3, respectively, and Examples 4, 5, and 6 according to the inventions of Claims 1 to 9 were prepared. did. 4. Two-stage polymer obtained in Synthesis Example 5 above. Was added to Formula A by 1, 2, and 3 parts by mass, respectively, to Formulation E-1 (Example 7),
E-2 (Example 8) and E-3 (Example 9). 3. Two-stage polymer obtained in Synthesis Example 4. Was added to Formula A to give Formula F (Example 10), and the two-stage polymer obtained in Synthesis Example 7 was used. Was added to Formula A, and Formulation H was used. As a comparative example, the two-stage polymer obtained in Synthesis Example 6 was used. Was added to Formula A, and this was designated as Formula G (Comparative Example 4). These formulas A to H were mixed with a screw extruder (75φ, L / D = 20) having a die attached to the tip thereof for 180 minutes.
Extrusion at 2.0 ° C. and inflation molding to obtain a heat-shrinkable film having a draw ratio of 2.0 to 4.5 times, 3.0 to 5.0 times, and a heat shrinkage of 40 to 50% (120 ° C.). . A retort puncture test was performed using the obtained film. The results are shown in Table 2.

[0052]

[Table 2]

[0053]

As is apparent from the above results, the present invention improves secondary processing characteristics such as rupture when performing raw retort sterilization of raw meat or the like using a (tubular) vinylidene chloride resin film. A vinylidene chloride resin composition containing a specific multistage polymer as a processing aid can be provided.

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Claims (17)

[Claims] 1. The method according to claim 1, wherein the at least one glass transition temperature is -4.
A vinylidene chloride-based resin composition comprising an acrylic resin having a weight average molecular weight of 250,000 to 1,000,000 at 0 ° C. or lower and a vinylidene chloride-based resin. 2. The weight average molecular weight of the acrylic resin is 25.
The vinylidene chloride resin composition according to claim 1, wherein the amount is from 10,000 to less than 400,000. 3. The vinylidene chloride resin composition according to claim 1, wherein the acrylic resin is a multi-stage polymer. 4. The vinylidene chloride resin composition according to claim 1, wherein the acrylic resin is substantially linear. 5. The vinylidene chloride resin composition according to claim 1, wherein the acrylic resin comprises a polymer (A) containing an acrylate ester as a main component. 6. An acrylic resin comprising an acrylate ester as a main component, and optionally at least one vinyl monomer selected from the group consisting of a methacrylate ester, a vinyl aromatic compound and a vinyl cyanide compound. One polymer (A) having a glass transition temperature of −40 ° C. or lower, and a methacrylate monomer or monomer mixture (B) polymerized in the presence of the polymer (A). The vinylidene chloride-based resin composition according to any one of claims 1 to 5, characterized in that: 7. The acrylic resin is an acrylic ester 7
0 to 100% by mass, and 30 to 0% by mass of at least one vinyl monomer selected from the group consisting of methacrylates, vinyl aromatic compounds and vinyl cyanide compounds, and at least one glass transition temperature of -40. ° C
20 to 80 parts by mass of the following polymer (A) and a monomer or monomer mixture (B) in which at least 80% by mass is a methacrylic acid ester in the presence of the polymer (A).
7. The vinylidene chloride resin composition according to claim 6, which is produced by polymerizing 20 parts by mass. 8. At least 90% by mass of an acrylic resin
The vinylidene chloride-based resin composition according to claim 7, comprising an acrylic ester of the above. 9. A polymer (A) constituting an acrylic resin
The vinylidene chloride resin composition according to any one of claims 5 to 8, wherein a weight average molecular weight of the vinylidene chloride resin composition is 200,000 or less. 10. The vinylidene chloride resin composition according to claim 9, wherein the polymer (A) constituting the acrylic resin has a weight average molecular weight of 5,000 to 150,000 or less. 11. An acrylic resin and a vinylidene chloride-based resin, wherein the acrylic resin is a multi-stage polymer, and the multi-stage polymer has a weight average molecular weight containing an acrylate ester as a main component of more than 60,000. The weight average molecular weight obtained by polymerizing a polymer (A) having a molecular weight of 150,000 or less and a monomer or a monomer mixture (B) of a methacrylate ester in the presence of the polymer (A) is 400,000 to 400,000. A vinylidene chloride-based resin composition, which is 1,000,000. 12. The method according to claim 1, wherein the at least one glass transition temperature is-
The vinylidene chloride resin composition according to any one of claims 1 to 11, further comprising another acrylic resin having a temperature of 40 ° C or lower and a weight average molecular weight of less than 20,000 to 100,000. 13. The vinylidene chloride resin composition according to any one of claims 1 to 12, comprising 0.05 to 10 parts by mass of an acrylic resin with respect to 100 parts by mass of the vinylidene chloride resin. 14. A molded article comprising the vinylidene chloride-based resin composition according to claim 1. 15. A film or casing in which the molded article according to claim 14 has heat shrinkability. 16. The molded product according to claim 14, which is a retortable film or casing. 17. A film or casing having a multilayer structure having at least one layer of the film or casing according to claim 15. Description: