JPH06270930A - Wrapping material for food and medical product - Google Patents

Abstract

PURPOSE:To obtain good appearance and transparency with small metal content by using vinyl chloride polymer manufactured by combination of partially saponified polyvinyl alcohol(PVA), secondary dispersant and water soluble cellulose ether whose mol% and average polymerization degree is respectively specific. CONSTITUTION:Vinyl chloride polymer obtained by suspension-polymerizing vinyl chloride or a mixture with monomer which can be copolymerized with vinyl chloride (vinyl chloride monomer) in an aqueous medium is molded to obtain a wrapping material for food and medical products. The vinyl chloride polymer is manufactured by using PVA having saponification degree of 70 to 90mol% and average polymerization degree of 1500 to 3000 based on 100 weight parts of vinyl chloride monomer and PVA having saponification degree of 70 to 90mol% and average polymerization degree of 300 to 1000, wherein their total is 0.06 weight part or more and 1.5 weight part or less, an amount of secondary dispersant is 0.005 weight part or more and 2.0 weight part or less, and an amount of aqueous cellulose ether is 0.005 weight part or more and 0.5 weight part or less, together as dispersion stabilizer at the time of suspension-polymerization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food / pharmaceutical packaging material such as a vinyl chloride resin-made food / pharmaceutical packaging container or a film, and particularly to a method for producing a food / pharmaceutical packaging material having a low metal content and a good appearance. .

[0002]

2. Description of the Related Art Vinyl chloride polymers (hereinafter referred to as PVC) are used in various fields because they have excellent physical and mechanical properties.

[0003] PVC is used in combination with various stabilizers for the purpose of suppressing decomposition during molding and processing, but a typical stabilizer type composite metal soap stabilizer is substantially non-toxic. It is preferably used in applications such as food and drug packaging materials that are required to exist.

When using such a composite metal soap-based stabilizer, a compound for promoting the effect of the stabilizer (hereinafter referred to as "stabilizing aid") is used. Polyols and / or their esters, phosphites, epoxy compounds and the like have been conventionally known, and they are used by adding them in advance during the production of PVC, or in the compounding and kneading steps prior to processing.

By the way, in food and drug packaging materials, there is a tendency to reduce the amount of stabilizer containing metal components as much as possible from a hygienic point of view.
The thermal stability of VC will fall. Therefore, it is necessary to promote the effect of the stabilizer in order to suppress the thermal decomposition of PVC during the molding of the food / pharmaceutical packaging material, or to suppress the decomposition of PVC during the sterilization by irradiation with ethylene oxide or gamma rays, and it is necessary to promote the effect of the stabilizer. Is used in combination.
However, the types and amounts of stabilizers that can be used are limited in consideration of toxicity, and these are FDA (US Food and Drug Administration), JHPA-PL (voluntary regulation standard for vinyl chloride resin food containers and packaging, positive list). ) And the like.

Among the usable types and amounts of stabilizing aids, when powder stabilizing aids are used, these compounds may have poor compatibility with PVC, resulting in poor dispersion. As a result, fish eyes may be generated to deteriorate the appearance of the product, and thus reduce the value of the product.

[0007] Among the usable stabilizing aids, liquid stabilizing aids volatilize from the molded product or directly transfer to the contacted contents, so that the contents may be odord, or the contents may deteriorate. It may cause discoloration, which is not preferable.

Further, PVA is a general dispersant for suspension polymerization of PVC, but it is classified as the above-mentioned polyol and has an effect as a stabilizing aid.
l. 47, No. 6, pp. 509 (June, 199
0) and the like. In addition, since PVA is a polymer, there is no problem of volatilization or migration from a molded product, and it is also approved to be used as a polymer additive by JHPA-PL described above. However, when using PVA for the purpose of improving the thermal stability of PVC,
When used in the mixing and kneading process, if PVA having a high saponification degree (particularly, PVA having a saponification degree of 70 mol% or more) is used, the compatibility with PVC is poor, resulting in poor dispersion and fisheye. It may impair sex and reduce the value of the product. When PVA having a low degree of saponification is used, it has to be used in a large amount because it has a poor ability as a stabilizing aid, and as a result, PV having a high degree of saponification is used.
It may cause the same problem as A.

On the other hand, when it is used as a dispersion stabilizer during the suspension polymerization of PVC to improve the thermal stability of PVC, P
Although the dispersibility of VA is improved, and the vinyl chloride monomer is graft-polymerized to PVA, the compatibility with PVC is improved, and fisheye and transparency are not deteriorated due to poor PVA dispersion. If a large amount of PVA is used for better thermal stability, the dispersion stability of the vinyl chloride monomer during suspension polymerization of PVC decreases and PVC
Or a polymer in which the plasticizer absorbency of the obtained PVC, fish eyes, and the level of vinyl chloride remaining in the PVC are reduced, and a food packaging container produced using such a polymer Causes another problem that the appearance and hygiene are unsatisfactory.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a food / pharmaceutical packaging material made of a vinyl chloride resin, which has a low metal content and is excellent in appearance and transparency.

[0011]

DISCLOSURE OF THE INVENTION As a result of intensive studies for solving the above problems, the present inventors have found that PVC produced by a suspension polymerization method using a dispersion stabilizer in a specific combination.
A food / pharmaceutical packaging material obtained by mixing a complex metal soap-based stabilizer with a stabilizer and forming the mixture has a low metal content, does not have a poor appearance due to fish eyes, etc., and has satisfactory transparency. The inventors have found the present invention and completed the present invention.

That is, the present invention provides a chlorinated product obtained by suspension polymerization of vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable with vinyl chloride (hereinafter referred to as vinyl chloride-based monomer) in an aqueous medium. In a food / pharmaceutical packaging material formed by molding a vinyl polymer, the vinyl chloride polymer (A) has a saponification degree of 70 to 90 mol% and an average degree of polymerization of 1500 to 30.
00 partially saponified polyvinyl alcohol (hereinafter, PVA
, (B) PVA having a saponification degree of 70 to 90 mol% and an average degree of polymerization of 300 to 1000, (C) a secondary dispersant, and (D) a water-soluble cellulose ether, (A)
The total amount of (B) is 0.06 parts by weight or more and 1.5 parts by weight or less based on 100 parts by weight of the vinyl chloride-based monomer, and the amount of (C) is 100 parts by weight of the vinyl chloride-based monomer. 0.005
The amount of (D) is 0.005 parts by weight or more and 0.5 parts by weight or less with respect to 100 parts by weight of the vinyl chloride-based monomer, and the dispersion stabilizer in suspension polymerization. It is a food and drug packaging material formed by using a vinyl chloride polymer produced in combination with the above. Hereinafter, the present invention will be described in detail.

In the present invention, an oil-soluble PVA or a surfactant is used as the secondary dispersant (C) used in the production of PVC used as a food / pharmaceutical packaging material by mixing with a composite metal soap stabilizer. You can

When oil-soluble PVA is used as the secondary dispersant (C), the total amount of the dispersion stabilizers (A) to (C) used is 0 based on 100 parts by weight of the vinyl chloride monomer. .0
The amount is preferably 65 parts by weight or more and 1.6 parts by weight or less, more preferably 0.1 parts by weight or more and 0.3 parts by weight or less. When the amount used is less than 0.065 parts by weight, sufficient heat stability cannot be obtained when a food / pharmaceutical packaging material is formed by mixing with a small amount of a composite metal soap stabilizer, resulting in poor hue and appearance. It is possible that only food and drug packaging materials can be obtained, and the long-term productivity (long run property) at the time of producing food and drug packaging materials may decrease due to extrusion molding or the like. On the other hand, when the amount is more than 1.6 parts by weight, the fish eyes in the obtained food / pharmaceutical packaging material are increased and the appearance is inferior, the transparency of the molded article is decreased, and the residual monomer in PVC is increased. In some cases, the amount of residual monomers in the food and drug packaging material increases and only the food and drug packaging material with poor hygiene can be obtained. The amount of the oil-soluble PVA used at this time is preferably 0.005 parts by weight or more and 0.1 parts by weight or less, and if less than 0.005 parts by weight, the fish eyes in the packaging material increase and the appearance is improved. As a result of inferiority or an increase in the residual monomer in PVC, the residual monomer in the packaging material increases and only a packaging material with poor hygiene can be obtained. 0.1
If it exceeds the weight part, fine particles will increase in the PVC, and the powder fluidity of the composition used for molding will decrease, resulting in fluctuations in the molding speed and the protrusion amount when the packaging material is obtained by extrusion molding. It may be difficult to obtain a packaging material of uniform quality, and even if the packaging material is obtained by another molding method, it may be an obstacle in handling such as weighing the composition. May decrease the uniformity.

When a surfactant is used as the secondary dispersant (C), the total amount of the dispersion stabilizers (A) to (B) used is 100 parts by weight of the vinyl chloride monomer. 0.
The amount is preferably 06 parts by weight or more and 1.5 parts by weight or less, and more preferably 0.1 parts by weight or more and 0.3 parts by weight or less. If the amount used is less than 0.06 part by weight, sufficient heat stability cannot be obtained when a food / pharmaceutical packaging material is formed by mixing with a complex metal soap-based stabilizer, resulting in a food having poor hue and appearance. There is a possibility that only pharmaceutical packaging materials can be obtained,
Long-run performance may decrease. On the other hand, when the amount is more than 1.5 parts by weight, fish eyes increase in the obtained food / pharmaceutical packaging material to deteriorate the appearance, and residual monomers increase to obtain only food / pharmaceutical packaging material with poor hygiene. There is a fear of not. Further, at this time, the amount of the surfactant used is preferably 0.05 parts by weight or more and 2.0 parts by weight or less, and if less than 0.05 parts by weight, the food and drug packaging material may have poor appearance and hygiene. On the other hand, when it exceeds 2.0 parts by weight, fine particles increase in PVC, and the powder fluidity of the composition used for molding of the food / pharmaceutical packaging material deteriorates. In some cases, it may be difficult to obtain a food and drug packaging material with uniform quality as a result of variations in the molding speed and the amount of protrusion when it is obtained by extrusion molding. Even if it is present, it may be an obstacle in handling such as measuring the composition, and may reduce the uniformity of the melting rate of PVC.

As the water-soluble cellulose ether used as the dispersion stabilizer (D), any of known water-soluble cellulose ethers such as methyl cellulose and hydroxypropyl cellulose may be used, and among them, hydroxypropyl methyl cellulose is particularly preferable. Used, and more preferably, PVC produced using hydroxypropylmethylcellulose having a hydroxypropoxyl group substitution degree of 0.15 to 0.25 and a methoxyl group substitution degree of 1.4 to 1.9 per glucose unit. Is preferred. The preferable amount used is 0.005 parts by weight or more and 0.5 parts by weight or less, and
If the amount is less than 005 parts by weight, the dispersion stability of the vinyl chloride-based monomer decreases, and as a result, no polymer is obtained or the obtained particles become coarse. The number of fish eyes increases and the appearance deteriorates. If it exceeds 0.5 parts by weight, fine particles will increase in the PVC, and the molding speed and the amount of protrusion will also vary, making it difficult to obtain a food and drug packaging material of uniform quality. This can cause problems.

The above-mentioned dispersion stabilizer may be used by adding the entire amount thereof to the polymerization system before the initiation of the polymerization, and a part of the dispersion stabilizer may be divided or continuous after the initiation of the polymerization and before the termination of the polymerization. It may be added and used, or may be added and used after the termination of the polymerization and before the dehydration of the slurry, but it is preferably added and used all at once before the start of the polymerization.

The vinyl chloride-based monomer used in the present invention for the production of PVC includes, in addition to vinyl chloride alone, a vinyl chloride-based monomer mixture (50% by weight or more of vinyl chloride). As a monomer copolymerizable with vinyl chloride to be provided in this mixture, vinyl acetate, vinyl ester such as vinyl propionate, methyl acrylate, acrylic ester such as ethyl acrylate or methacrylic acid ester, Examples thereof include olefins such as ethylene and propylene, maleic anhydride, acrylonitrile, styrene and vinylidene chloride.

The surfactant used in the production of the PVC used in the present invention may be any of nonionic, cationic and anionic surfactants, such as glycerin fatty acid ester, polyglycerin fatty acid ester and propylene glycol fat. Mura ester, sorbitan fatty acid ester, polyoxyethylene fatty alcohol ether, sorbitan fatty acid ester of polyoxyethylene, glycerin fatty acid ester of polyoxyethylene, block copolymer of polyoxyethylene and polyoxypropylene, polyoxyethylene alkylphenyl ether,
Nonionic surfactants such as nonylphenyl polyoxyethylene phosphoric acid; cationic surfactants such as aromatic ammonium salts, alkyl amine salts, quaternary ammonium salts, alkyl imidazoline quaternary salts; alkyl sulfonates
There are anionic surfactants such as alkylallyl sulfonates, alkyl phosphates, polyoxyethylene alkyl phosphates, polyoxyethylene alkylallyl sulfonates, which may be used alone or in combination of two or more. However, the hydrophilic / hydrophobic balance is 15
Must be less than or equal to 15
Is not obtained, the number of fish eyes in the food / pharmaceutical packaging material is increased, and the residual monomer in PVC is increased. As a result, the residual monomer in the food / pharmaceutical packaging material is increased and the hygienic property is deteriorated. Sometimes you can only get it.

There are no particular restrictions on the polymerization conditions in the method for producing PVC used for molding food / pharmaceutical packaging materials in the present invention, and known conditions for suspension polymerization can be used. For example, the amount of the aqueous medium, the amount of the polymerization initiator, the polymerization temperature, and the like used per monomer may be in the range conventionally used. If necessary, a known protective colloid, p
H regulators, chain transfer agents and the like may be used as long as they do not affect the effects of the present invention. Further, as described later, in the case of using an organotin stabilizer in combination with a complex metal soap stabilizer, a PVC produced using a chain transfer agent having a mercapto group and a hydroxyl group and / or a carboxyl group. It is preferable to use PVC, and it is preferable to use PVC produced using a chain transfer agent having a mercapto group and a hydroxyl group and / or a carboxyl group even when the food and drug packaging material is subjected to gamma ray sterilization. As such a chain transfer agent,
2-Mercaptoethanol, 3-mercaptopropanol, 4-mercaptobutanol, thioglycerin, thiopropylene glycol, thioacetic acid and the like are exemplified, and among them, 2-mercaptoethanol is preferably used.

The composite metal soap-based stabilizer used in combination with PVC is a combination of a commonly used organic acid salt of zinc and an organic acid salt of alkali metal and / or alkaline earth metal. Examples of the type of metal include lithium, sodium, potassium, magnesium, calcium, and the like. Among them, a combination of calcium and zinc or a combination of barium and zinc is preferable. Examples of the organic acid include, but are not limited to, carboxylic acids such as formic acid, acetic acid, propionic acid, caprylic acid, lauric acid, palmitic acid, and stearic acid.

Further, the food / pharmaceutical packaging material of the present invention includes a stabilizing aid such as a phosphite, an epoxy compound, a polyol such as dipentaerythritol or a derivative thereof, an antioxidant, a zeolite, a perchlorate, and a processing aid. , Plasticizers, lubricants, pigments, fillers, organic tin stabilizers and other usual additives,
Furthermore, resins other than vinyl chloride-based resins and other modifiers may be mixed within a range that does not affect the effects of the present invention.

The method of mixing PVC with the complex metal soap stabilizer and other additives may be a conventionally used method, for example, using a mixer such as a Henschel mixer or a super mixer or a ribbon blender at room temperature. A method of mixing under heat or by heating is adopted.
Further, the powder composition mixed as described above may be once pre-kneaded and then pelletized, or the powder composition may be used as it is. It is also possible to directly supply a part of the additives to a molding machine when molding the food / pharmaceutical packaging material for use.

The method of molding the mixture into a food / pharmaceutical packaging material may also be a conventionally used method. In the case of forming a film for food / pharmaceutical packaging, extrusion molding is generally used, and food / pharmaceutical packaging is used. In the production of a container, a sheet obtained by extrusion molding, calender molding or the like is made into a food / pharmaceutical packaging container by vacuum molding or the like, or injection molding, blow molding or the like is used. At that time, the type of extruder or other molding machine, the shape of the screw, the temperature of the cylinder and the die, and other molding conditions may be those conventionally used and are not particularly limited.

[0025]

EXAMPLES The present invention will be described below based on Examples and Comparative Examples, but the present invention is not limited to these.

The following physical properties were measured by the following methods.

1. Preparation of composition 1) Blending Vinyl chloride resin 100 parts by weight MBS ^* 3.0 parts by weight Epoxidized soybean oil 3.0 parts by weight Hindered phenolic antioxidant 0.5 parts by weight Stearic acid 0.3 parts by weight Stearyl Alcohol 0.5 parts by weight Partially saponified montanic acid wax 0.2 parts by weight Ca-Zn-based composite stabilizer Variable * Methyl methacrylate-butadiene-styrene terpolymer After weighing according to the above formulation, mixed with a Henschel mixer To obtain a composition.

2) Mixing conditions Mixer capacity: 20 L Vinyl chloride resin amount: 5 kg Mixing termination conditions: Mixing was terminated when the resin temperature reached 120 ° C.

2. Thermal stability test method The composition prepared by the method described in the previous section was mixed with a Brabender Plastograph tester at a mixer rotation speed of 6
60 g under the conditions of 0 rpm and chamber temperature of 160 ° C
From the time point (a) when the maximum torque is reached after the input of
Torque starts to rise again due to resin decomposition (b)
The difference in time until was taken as the thermal decomposition time. The judgment was that the thermal decomposition time was 10 minutes or longer and the thermal stability was acceptable, and the thermal decomposition time was 10 minutes or less.

Thermal decomposition time (HDT, min) = (b) − (a) In the composition which fails thermal stability, when a sheet is obtained by the method described in item 4, the sheet has a yellowish appearance. May damage.

3. Minimum required amount of stabilizer Ca-for passing thermal stability by the method shown in the previous section
The minimum required amount of Zn-based composite stabilizer was determined. At that time, Ca
The amount of the Zn-based composite stabilizer added is 0.4 parts by weight to 1.
The test was conducted by changing every 0.2 parts by weight up to 2 parts by weight.

4. Amount of Residual Monomer in Sheet A composition having the minimum amount of stabilizer in the preceding paragraph was molded under the following conditions to obtain a sheet having a thickness of 0.5 mm, and the amount of residual monomer in the sheet was changed to ASTM D 3749-87. It measured according to it. 1) Kneading machine conditions Kneading machine: BUSS Co-kneader (PR-40) Extrusion rate: 18 kg / 1 hour Die temperature: 180 ° C Barrel temperature: 90 ° C Scree temperature: 60 ° C 2) Calender molding conditions Calendar molding machine: Sakurai roll Reverse L-type 6-inch 4-roll calendering machine manufactured by the company Roll temperature: first roll 170 ° C .: second roll 170 ° C .: third roll 175 ° C .: fourth roll 180 ° C. Sheet thickness: 0.5 mm.

EXAMPLE 1 450 kg of deionized water, 400 kg of vinyl chloride monomer, were placed in a stainless steel polymerization container having an internal volume of 1 cubic meter.
The type and amount of the dispersant shown in the above are charged as an aqueous solution or a mixed solution of methyl alcohol and water, and as an initiator, t
-Using 0.04 parts by weight of butylpaoxypivalate,
The reaction was carried out at a temperature of 63.5 ° C to a conversion rate of 85%. The water-soluble cellulose ether had a hydroxypropoxyl group substitution degree of 0.25 and a methoxyl group substitution degree of 1.9, and the viscosity of a 2% by weight aqueous solution at 20 ° C. was 50 cps. Hydroxypropyl methylcellulose (HPMC) was used.

After the polymerization, the unreacted vinyl chloride monomer is recovered, the system is evacuated and replaced with nitrogen, and then the vinyl chloride polymer slurry is taken out and dehydrated and dried to obtain a polymer. After adjusting the composition, a part of the composition is subjected to a heat stability test to obtain the minimum required stabilizer amount, and the remaining amount of the composition having the minimum required stabilizer amount is subjected to molding of a sheet for food and drug packaging to obtain the obtained amount. The amount of residual vinyl chloride in each sheet was measured.

Example 2 Example 2 was repeated except that 0.05 part by weight of PVA (A) was used as the secondary dispersant.

Example 3 PVA (C) was used in an amount of 0.02 part by weight,
The same procedure as in Example 2 was performed.

Example 4 Example 4 was repeated except that the amount of HPMC used was 0.05 parts by weight. Example 5 Example 5 was repeated except that 0.2 part by weight of sorbitan monostearate was used instead of PVA (C).

Comparative Example 1 Example 1 was repeated except that PVA (A) was not used.

Comparative Example 2 The procedure of Example 1 was repeated except that PVA (B) was not used.

Comparative Example 3 The procedure of Example 1 was repeated except that PVA (C) was not used.

Comparative Example 4 The procedure of Example 1 was repeated except that HPMC was not used.

Table 1 shows the dispersant formulation of each Example and Comparative Example.

[0043]

[Table 1]

Table 2 shows the evaluation measurement results of each Example and Comparative Example.
Shown in.

[0045]

[Table 2]

In Comparative Examples 1 and 4, blocks were formed and a polymer could not be obtained. In Comparative Example 2, the obtained polymer has poor thermal stability, and the minimum necessary amount of stabilizer is
It was 1.0 part by weight. In Comparative Example 3, the minimum necessary amount of stabilizer was as small as 0.6 parts by weight, but the amount of residual monomer in the sheet was as high as 15 ppb and the sheet was inferior in hygiene.
Examples 1 to 5 were sheets having a small amount of stabilizer and excellent hygiene without various problems as seen in Comparative Examples.

[0047]

According to the food / pharmaceutical packaging material of the present invention, the metal content contained therein can be reduced without impairing the transparency of the appearance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08F 2/20 MBK 7442-4J 14/06 C08L 27/06 LFT 9166-4J

Claims (1)

[Claims] 1. A mixture of vinyl chloride or a monomer copolymerizable with vinyl chloride (hereinafter referred to as vinyl chloride monomer).
A vinyl chloride polymer obtained by suspension polymerization in an aqueous medium, wherein the vinyl chloride polymer is (A) having a saponification degree of 70 to 90.
Partially saponified polyvinyl alcohol (hereinafter referred to as PVA) having a mol% and an average degree of polymerization of 1500 to 3000,
(B) Saponification degree is 70 to 90 mol% and average degree of polymerization is 3
The total amount of (A) and (B) is 0.0 to 1000 PVA, (C) a secondary dispersant, and (D) a water-soluble cellulose ether, based on 100 parts by weight of the vinyl chloride-based monomer.
6 parts by weight or more and 1.5 parts by weight or less, the amount of (C) is 0.005 parts by weight or more and 2.0 parts by weight or less, and the amount of (D) is vinyl chloride based on 100 parts by weight of the vinyl chloride monomer. Monomer 1
A food product obtained by molding a vinyl chloride polymer produced by using 0.005 parts by weight or more and 0.5 parts by weight or less with respect to 00 parts by weight of a vinyl chloride polymer produced as a dispersion stabilizer in suspension polymerization. Pharmaceutical packaging material.