JPH0565384A - Degradable antibacterial polymeric composition - Google Patents

Abstract

PURPOSE:To obtain a polymeric composition which has antibacterial properties when used and is biodegradable when discarded by mixing a specified partially saponified polyvinyl alcohol and a sucrose ester of a fatty acid. CONSTITUTION:The objective degradable antibacterial polymeric composition contains 20-80wt.% partially saponified polyvinyl alcohol having a degree of saponification of 90mol% or lower, 1-20wt.% sucrose ester of a fatty acid, 0-5wt.% alginic acid, and 0-25wt.% plasticizer. Polyvinyl alcohols are biodegradable. Since such bacteria that can proliferate by utilizing the residual acetyl groups of partially saponified polyvinyl alcohol are found, a partially saponified polyvinyl alcohol is preferable when considering the plasticity together with the biodegradability. As the sucrose ester of a fatty acid, a tasteless, odorless and edible surface active agent which is digested and absorbed in the body is preferable to be as a very safe compound. In addition to the antibacterial properties, it has an excellent plasticizing effect and an excellent ability to disperse both inorganic and organic fillers.

Description

Detailed Description of the Invention [Object of the Invention]

[0001]

TECHNICAL FIELD The present invention relates to a disintegrating antibacterial polymer composition which exhibits antibacterial properties when used and can be decomposed by microorganisms when disposed of.

[0002]

2. Description of the Related Art Polymer compounds having photodegradable or biodegradable functions have been investigated in order to reduce the environmental impact of discarded polymer compounds as much as possible. In terms of degradability, practically satisfactory ones have not yet been obtained.

As the photodegradable one, there are a method of synthesizing a sensitized copolymer and a method of using an additive for photosensitizing the copolymer. For example, ethylene / carbon monoxide copolymer,
Examples include vinyl ketone polymers, aromatic ketone additives, and metal complex sensitizers.

Examples of biodegradable substances include polyethylene / starch mixtures, caprolactone polyesters, polyhydroxybutyrate / valerate copolymers and the like.

Even if a degradable polymer compound is obtained, such a compound has a drawback that it is easily attacked by various bacteria during use, which is a very important problem particularly in the case of food packaging.

In the prior art, polymer compounds satisfying the disintegrating property and the antibacterial property have not been obtained yet.

[0007]

DISCLOSURE OF THE INVENTION Disintegration for the above purpose, which has the same price as existing polymer compounds and has antibacterial properties at the time of use and biodegradability at the time of disposal. It is possible to produce an antibacterial polymer composition in the form of a practical composite material.

[0008]

[Constitution of the invention]

[Means for Solving the Problems] The polymer compound for the above purpose is a polymer compound which can be synthesized from an existing material as a starting material in an existing facility without a new facility investment and which does not increase the manufacturing cost. Of the composition based on the characteristics of
This can be achieved by preparing a composite material having properties which have not been observed in the past, which make use of the respective characteristics, obtained by reexamination of the relationship between the chemical structure of food additives and the antibacterial property.

Partially saponified polyvinyl alcohol was taken as the main component. The saponification rate is 90 mole% or less, preferably 50 to 88 mole%, which meets the object of the present invention.

That is, completely saponified polyvinyl alcohol
It is very difficult to give plasticity at practical temperatures.

For example, the temperature 170 of the operation normally used
In order to impart plasticity to the above compound at 0 ° C., the amount of glycerin added is about 60% by volume, and the tackiness and hygroscopicity become large, which is not suitable for practical use.

If the residual acetic acid group content is 10 mole%, then 1
Since there is a possibility of plasticizing even at 80 ° C., plasticity can be imparted by adding a plasticizer and heating when processing a film or various molded products.

Further, since polyvinyl alcohol is plasticized by a polyvalent alcohol type compound, addition of these may be considered in order to further improve workability.

As such a plasticizer, glycerin,
Examples thereof include glycols and ethanolamine.

Other anionic nonionic surfactants also have a plasticizing effect, but those having a large plasticizing effect on polyvinyl alcohol generally have a high hygroscopicity, and the addition amount is determined in consideration of the influence of humidity. Must.

Therefore, it is desirable that the polyvinyl alcohol used has a suitable saponification rate and the addition amount of the plasticizer is made as small as possible.

Polyvinyl alcohols are decomposed by microorganisms. For example, Pseudomonas and Xanthomon
Since it is decomposed by as, if plasticity at low temperature is given, workability is improved and practicality as a main component comes out.

Further, in the partially saponified product, bacteria which utilize the residual acetyl group to grow are also found,
Considering both plasticity and biodegradability, the use of partially saponified polyvinyl alcohol is desirable.

However, the disadvantage of being susceptible to various bacteria associated with microbial degradability is unavoidable, and therefore it is conceivable to use a compound that is itself completely microbial degradable and antibacterial.

As a material that can be used for such a purpose,
There is sucrose fatty acid ester.

Sucrose fatty acid ester is a tasteless and odorless edible surfactant composed of natural products of sucrose and fatty acids. It is digested in the body and absorbed as sucrose and fatty acids, and is used without limitation for foods. It is a very safe compound and has an excellent plasticizing effect on partially saponified polyvinyl alcohol and a dispersing effect on inorganic and organic fillers, in addition to the above-mentioned antibacterial properties.

There are various products of sucrose fatty acid ester. For example, lauric acid ester is Escherichia.
The growth of Coli can be stopped.

Also, palmitic acid and stearic acid ester suppress the growth of thermophilic anaerobic cell spores isolated as flat-saw spoilage bacteria.

As described above, since the main purpose of the antibacterial property of sucrose fatty acid ester is to prevent the growth of microorganisms, active bactericidal properties cannot be expected.

Therefore, in the present invention, as a method for the case where bactericidal properties are required, the property that polyvinylpyrrolidone easily forms an addition compound with iodine is utilized, and iodine is added to a polyvinylpyrrolidone-alcohol solution. -A method in which an addition compound obtained by adding an alcohol solution was added to the above-mentioned polymer composition and bactericidal properties could be expected could be put into practical use.

The polyvinylpyrrolidone / iodide addition compound is described as polydone iodine in the Japanese Pharmacopoeia and used as a bactericide.

Since this product has a brown color tone,
The amount added is naturally limited.

Further, in the present invention, bacteriostatic property, odor absorbing property,
The addition of alginic acid was investigated for the purpose of improving the dispersibility of inorganic and organic fillers and the film forming ability.

Alginic acid is an organic polyelectrolyte and its C
Since the OOH group has a very high activity and is chemically bonded to a metal ion, it has an inhibitory effect on the system in which the metal ion serves as a catalyst to cause fermentation oxidation.

As can be seen from the structure, alginic acid has no side chain other than the COOH group and is composed of H and OH groups having strong hydrophilicity, and therefore exhibits extremely strong hydration property.

Therefore, the water required by the microorganisms is removed,
It has the effect of inhibiting its growth. Further, this highly active COOH group has a very large ability to absorb a nitrogen-based volatile compound such as ammonia and trimethylamine, and thus can be used as a malodor absorbent.

Alginic acid is starch, protein,
Easy to mix with organic substances such as sucrose and glycerin,
Since it has a very high affinity with inorganic substances such as calcium carbonate and silica, it is effective in dispersing various fillers used in the present invention.

Further, since alginic acid is a filamentous polymer,
The ability to form fibers and films is extremely large.

Since the above-mentioned polymer composition is generally used as a film or a molded product, the required strength is required according to the purpose of each, but in the field where the strength is not required, the following interesting usage method is used. There is.

Generally used superabsorbent polymer compounds absorb water themselves to form gel particles and do not form a continuous film, and since they have no adhesive property, they are not coated by themselves. It cannot be used as a work material.

Therefore, dispersion in a solvent system containing no water can be considered. In this case, however, the surface of the superabsorbent polymer is covered with the solvent-soluble resin, so that the water absorption is greatly reduced and the original I can't reach my purpose.

In the alginic acid-containing system used in the present invention, the superabsorbent polymer compound is very easily dispersed to form an almost continuous film.

The film thus obtained is a very characteristic film which has disintegrating and antibacterial properties and also has odor absorbing properties and water absorbing properties.

When this film is used in the structure of, for example, a diaper or a physiological zone, a new product having an odor absorbing property and an antibacterial property is obtained, unlike a conventional product having only water absorption.

If the other constituents of these products are prepared in a disintegrating way, new concepts of products in the field of these products can be created.

Generally, superabsorbent polymer compounds can be roughly classified into the following three types.

(1) Starch-based highly water-absorbing polymer compound This type of polymer compound is obtained by graft-polymerizing acrylonitrile onto starch and then subjecting it to alkali hydrolysis,
What was prepared by drying and then pulverizing was also prepared by using a monomer such as starch, acrylic acid, acrylamide and a cross-linking agent, or one prepared by cross-linking carboxymethyl starch with formalin. and so on.

(2) Cellulose type superabsorbent polymer compound Cellulose is used instead of starch in the starch type polymer of (1).

(3) Synthetic polymer superabsorbent polymer compound The polymer compound of this system is obtained by subjecting a basic polymer compound composed of polyacrylic acid, polyacrylonitrile, polyvinyl alcohol, etc. to a crosslinking treatment, a hydrophilic treatment and the like. It is a thing.

In the present invention, the superabsorbent polymer compound (3) having the characteristic of photodegradability is used.

Further, in order to reduce the cost of the polymer composition, the addition of soybean meal after protein extraction, which causes a great problem in disposal, was examined, and it was found that the effect was great.

The components of soybean meal are shown in Table 1.

Table 1 Soybean meal analysis value Moisture 6.6 (%) Protein 24.0 Lipid 17.3 Fiber 13.8 Ash 3.5 Sugar 34.8 (% is% by weight)

As shown in Table 1, soybean meal contains a large amount of proteins, lipids and sugars which have an effect on microbial decomposition, but at the same time, since a large amount of fiber is also present, the polymer Although it is very difficult to disperse it in the system, a good dispersion was obtained due to the dispersing effect of the sucrose fatty acid ester used in the present invention as a surfactant.

As described above, a polymer composition having an antibacterial property when used, or a bactericidal property as required, and a microbial degradability at the time of disposal was obtained.

Table 2 summarizes the composition.

Table 2 Composition Partially saponified polyvinyl alcohol 20 to 80% (saponification degree 90 mole% or less) Sucrose fatty acid ester 1 to 20% Alginic acid 0 to 5% Plasticizer 0 to 25% Polyvinylpyrrolidone yo-yo Addition compound 0.01 to 1% Super absorbent polymer 1 to 5% Soybean meal 5 to 20% (% is% by weight)

When a film having a thickness of about 25 μm obtained from the polymer composition obtained in Table 2 is immersed in an aqueous solution in which lipolytic enzyme lipase is dispersed, it is 12 hours to 24 hours.
The polymer composition is decomposed over time, and the entire solution becomes cloudy.

When the film was buried in the soil, it was found that the film collapsed in 3 to 6 months before the original shape was almost stopped.

The above-mentioned film was attached to an agar medium prepared by using Bacillus subtilis as a test bacterium, and the effect of suppressing the growth was examined. It was confirmed that it exhibited an action.

As shown in Table 2, the composition of Table 2 is made of all organic substances, but generally used inorganic fillers are used according to their purposes.

For example, titanium white, calcium carbonate, silica, zeolite, talc, zinc white, etc. can be used.

Further, one of the great uses of the polymer composition of the present invention is the combined use of an inorganic fine hollow body.

The main component of this glass-like expanded particle is silica 7
0 to 77% and 12 to 17% alumina, which can be easily dispersed in the polymer composition shown in Table 2 similarly to the above-mentioned inorganic filler, and have a function similar to a foamed styrene molded product and the characteristics of the present invention. It is possible to obtain a lightweight molded product having

Moreover, since this molded product has a small calorie burning, it can be burned in an ordinary combustion furnace when it is discarded.

[0061]

EXAMPLES Next, the present invention will be specifically described with reference to Examples.
This does not limit the invention. Parts indicate parts by weight.

Example 1 100 parts of partially saponified polyvinyl alcohol (containing 94% of PVA) prepared with a saponification ratio of 88 mole% and glycerin 3
0 parts, 10 parts of sucrose lauric acid ester, and 100 parts of water were mixed and melted at a temperature of 80 to 80 ° C. for 5 minutes and extruded from an extruder to obtain pellets.

Then, using the pellets, a film having a thickness of about 25 μm was prepared by an inflation method.
The disintegration and antibacterial properties were tested.

When a section of the film is immersed in an aqueous Pseudomanas solution, it is decomposed into a cloudy solution.

When it is buried in the soil, it decomposes into small pieces after 6 months. Similarly, this film was attached to an agar medium prepared using Bacillus sublitis as a test strain to examine the effect of growth inhibition, but the growth was inhibited and its antibacterial effect was clearly observed.

Further, among the physical properties of the obtained film, it was confirmed that the film had an elongation of 250% and a tear strength of 400 gr / mil and had a strength equivalent to that of a general thermoplastic resin.

Here, the water content of the film is 15
%, The plasticity of the film increases and the elongation is 350.
%, Tear strength is 300 gr / mil.

Example 2 100 parts of partially saponified polyvinyl alcohol (containing 94% PVA) and glycerin 2 prepared to have a saponification rate of 88%.
0 parts, 10 parts of sucrose lauric acid ester, and 10 parts of soybean meal were mixed and melted with 50 parts of water at a temperature of 80 to 85 ° C. for 5 minutes and extruded from an extruder to obtain pellets.

Then, using this pellet, a film having a thickness of about 25 μm was prepared by an inflation method.
The disintegration and antibacterial properties were tested.

When the section of the film is immersed in the lipolytic enzyme lipase solution, it is easily decomposed at room temperature to give a cloudy solution.

When it is buried in the soil, it decomposes into small pieces after 4 months. Similarly, this film was attached to an agar medium prepared using Bacillus sublitus as a test strain to examine the effect of suppressing growth, but the growth was inhibited and its antibacterial effect was clearly observed.

The presence of soybean meal is very effective for microbial degradation. Of the physical properties of the obtained film,
It was confirmed that it has the same strength as a general thermoplastic resin with an elongation of 300% and a tear strength of 300 gr / mil.

Example 3 A film obtained from the composition obtained by adding 0.1 part of the polyvinylpyrrolidone iodine addition compound containing 5% of the effective iodine in Example 1 was tested for antibacterial properties.

Degradation due to thermophilic bacteria has been a problem in this canned coffee or syrup. The effect of growth inhibition by attaching the above film to a TSiF medium using these thermophilic bacteria as a test bacterium. However, they were able to completely inhibit their growth.

The film of Example 3 can be expected to have the effect of exhibiting a bactericidal action or more than an antibacterial action.

Example 4 100 parts of partially saponified polyvinyl alcohol (containing 96% of PVA) prepared with a saponification ratio of mole of 71%, glycerin 2
0 parts, sucrose oleate 10 parts, alginic acid 5
Part and 40 parts of water were mixed and melted at a temperature of 80 to 85 ° C. for 5 minutes and extruded from an extruder to form a film having a thickness of about 25 μm by an inflation method.

The film obtained here is biodegradable, has the function of absorbing nitrogen-based volatile compounds such as ammonia trimethylamine, and has antibacterial properties. Therefore, it has an excellent freshness-keeping ability in food packaging. Was found to have

Example 5 100 parts of partially saponified polyvinyl alcohol (containing 96% PVA) and glycerin 2 prepared to have a saponification ratio of 88 mole%
0 part, sucrose oleate 20 parts, soybean meal 10
Parts, water 50 parts, acid clay 40 parts at a temperature of 80 to 85 ° C.
A sheet having a thickness of about 3 mm was prepared by using a pellet obtained by mixing and melting for a minute and extruding from an extruder.

This thermoplastic sheet is molded as a tray and has the function of absorbing nitrogen-based volatile compounds such as ammonia and trimethylamine as well as the film of Example 4 in the sale of fresh fish and shellfish and livestock meat. When used together, it has a great effect on maintaining their freshness, and when it is buried in the soil, it collapses into small pieces in about 6 months.

Further, at the time of incineration, the calorific value is reduced to almost half.

Example 6 100 parts of partially saponified polyvinyl alcohol (containing 96% of PVA) prepared to a saponification rate of 88 mole% and glycerin 2
0 parts, sucrose oleate 10 parts, soybean meal 15
Part and 200 parts of water were mixed at a temperature of 50 to 60 ° C. for 5 minutes to prepare a film by a Tidye method.

The soybean meal is easily dispersed, and a film having high transparency is obtained. The water content of this film was 7%, and a flexible film was obtained.

As in this example, it is very difficult to disperse an organic filler such as soybean meal or corn starch in a polymer compound, and it is necessary to study an appropriate dispersant in advance and carry out a preliminary treatment. However, in this example, the dispersion could be carried out very easily.

Of the physical properties of the film obtained here,
It was confirmed that it has the same strength as a general thermoplastic resin with an elongation of 310% and a tear strength of 300 gr / mil.
Moreover, this film completely collapses into small pieces when it is buried in the soil for 4 months.

Example 7 100 parts of partially saponified polyvinyl alcohol (containing 96% PVA) prepared with a saponification ratio of 88 mole% and glycerin 2
0 parts, sucrose oleate 10 parts, alginic acid 2
Part, a super absorbent polymer (polyacrylic acid) 5 parts, and water 50 parts were mixed at a temperature of 80 to 85 ° C. for 5 minutes to prepare a film by a Tidye method.

It was revealed that the diaper using the film having a thickness of about 40 μm obtained as a constituent material has an odor absorbing function in addition to the conventional water absorbing function.

Diapers using the film of this example
Is the photodegradability of the super absorbent polymer used here,
In addition to the original functions of water absorption, antibacterial properties, and odor absorption due to the microbial degradability of other main components, it also satisfies the environmentally required disintegration properties.

Example 8 100 parts of partially saponified polyvinyl alcohol (containing 96% of PVA) prepared to a saponification rate of 88 mole% and glycerin 2
0 parts, sucrose lauric acid ester 10 parts, alginic acid 2
Part, superabsorbent polymer compound (polyacrylic acid) 2 parts, inorganic fine airborne material 40 parts, and water 70 parts by mixing for 5 minutes at a temperature of 80 to 85 ° C. About 1
A 0 mm plate was molded.

The molded product obtained in this example has sufficient strength in a normally used environment and can be used as a transportation container for fresh fish and the like, but when immersed in water, it gradually penetrates due to penetration into the interior. It collapses into small pieces, reducing its volume and making it easy to discard.

Example 9 A film having tensile strength was obtained by an inflation method from a composition obtained by adding 30 parts of polyethylene (LDPE) powder (Japan Unicar EG030) to the formulation of Example 7.

The film obtained here is biodegradable, has a function of absorbing a nitrogen-based volatile compound such as ammonia trimethylamine, and has antibacterial properties. Therefore, it has an excellent freshness-keeping ability in food packaging. Was found to have

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location C08L 29/04 LGP 6904-4J LGT 6904-4J // (C08L 29/04 5:04 6770-4J 39:06 7242-4J 99:00 6770-4J 101: 00) 7167-4J (72) Inventor Shiro Kojima 2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd. (72) Invention Person Yoshiki Suzuki 2-3-13, Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd. (72) Inventor Katsumi Nishimura 2-3-3, Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd. (72) Inventor Kaneko Kiyoshi, Kanagawa Prefecture, Kanagawa Prefecture, 3-2-23 South East Coast East Coast

Claims (5)

[Claims] 1. A partially saponified polyvinyl alcohol having a saponification degree of 90 mole% or less 20 to 80% by weight, sucrose fatty acid ester 1 to 20% by weight, alginic acid 0 to 5% by weight, and a plasticizer 0 to 25% by weight. Disintegrating antibacterial polymer composition containing. 2. The disintegrating antibacterial polymer composition according to claim 1, further comprising a polyvinylpyrrolidone / iodo addition compound in an amount of 0.1 to 1% by weight. 3. The soybean meal after protein extraction is further treated with 5
The disintegrating antibacterial polymer composition according to claim 1, wherein the disintegrating antibacterial polymer composition is mixed in an amount of about 20% by weight. 4. The disintegrating antibacterial polymer composition according to claim 1, wherein the superabsorbent polymer compound is contained in an amount of 1 to 5% by weight. 5. The disintegrating antibacterial polymer composition according to claim 1, which contains 10 to 50% by weight of an inorganic fine hollow body.