JPH066672B2 - Resin composition, molded product thereof and production method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition having a remarkable effect in retaining fresh foods such as fruits and vegetables and fresh animal foods, molded products utilizing the attributes thereof, and their production. It is about the method.

2. Description of the Related Art Conventionally, it is well known that a fine porous material such as activated carbon or zeolite is used and used as a dehumidifying agent or a deodorant.

In addition, when storing fresh foods, especially fruits and vegetables such as vegetables and fruits, the preservation performance is related to the amount of ethylene produced by the fruit itself, and is dramatically improved by removing ethylene gas from the storage. It is known that the freshness can be maintained for a long time.

From this point of view, focusing on low molecular gas adsorption performance such as ethylene gas of a fine porous material mainly containing silicic acid anhydride such as Otani stone, zeolite or cristobalite, a film of a polyethylene-based polymer material containing these fine porous materials ,
Alternatively, a wrapping paper for storing fruits and vegetables has been proposed in which the above-mentioned thin porous material is mixed with an oxygen-treating low-molecular gas adsorption oxidation catalyst which is treated with electromagnetic waves or ozone to treat oxygen (food constant temperature distribution, Vol. 16 No. 2). , JP-A-61-93835).

Problems to be Solved by the Invention The polyethylene film is produced by an inflation method by mixing a pellet-shaped resin raw material and a low molecular weight gas adsorbing fine porous material, and a film or a laminate thereof and It is provided and used in the form of a bag.

However, this is because it is in the form of a film, and because the resin and the low molecular gas adsorbing fine porous material cannot be sufficiently mixed due to the manufacturing method, the content of the fine porous material is limited and the fine porous material is limited. Although it contains quality materials, its performance is insufficient for long-term freshness retention for products that generate a large amount of ethylene gas, and at the time of retail sale, rather tray-shaped containers are mainly used. A thermoplastic resin composition that can be molded into a container for keeping freshness has been awaited.

Especially in the fields of preservation and transportation of fruits and vegetables, etc.
Maintaining freshness for a long time is a very important and important issue for producers and distributors. Therefore,
It is desired to utilize the properties of such a low molecular gas adsorbing fine porous material as effectively as possible.

It is an object of the present invention to provide a method capable of containing a fine porous material in a small amount to a large amount, so as to be compatible with a resin, a novel fine porous material-containing resin composition produced by the method, and It is to provide a molded product using the resin composition.

Means for Solving the Problems The inventors of the present invention have conducted extensive studies based on the above-mentioned object, and as a result, denature the low-molecular-gas-adsorbing fine porous material with a fatty acid and / or a derivative thereof and heat the same. The thermoplastic resin and the microporous material are compatiblely mixed by stirring and mixing with the thermoplastic resin, and further, the microporous material can be used in a thermoplastic resin from a low content to a high content. The inventors have found that they can be mixed together appropriately and have completed the present invention.

The fine porous material-containing thermoplastic resin composition according to the present invention,
The fine porous material wrapped with a fatty acid and / or a derivative thereof has a general island-sea structure in which the fine porous material is dispersed in a thermoplastic resin phase. This resin composition can also be melted and pelletized. Pelletization can be performed by any of sheet cutting method, strand cutting method, air cooling die surface cutting method, water cooling die surface cutting method, etc. after melting the resin composition. The shape of the pellet is not limited to corners, cylinders, and spheres, and it may be a cylinder whose end surface is a plane / convex surface, both convex surfaces, concave surface / convex surface or both concave surfaces, or those in which a protrusion is formed on these end surfaces. It can be shaped.

Further, the resin composition according to the present invention is kneaded by an extrusion molding machine or the like, and is manufactured into various molded products such as a sheet and a container containing a large amount of a fine porous material by using a T die, a calender roll or an injection molding machine. Can, freshness container for fruits and vegetables,
It can be used for various purposes such as building materials.

The thermoplastic resin used in the present invention includes polystyrene, polypropylene, polyvinyl chloride, polyethylene and the like, and heterogeneous mixed resins thereof, such as polystyrene (GPPS, HI
Polystyrene (including PS) is most preferable, and polystyrene is excellent in freshness retention performance even when molding a packaging container for perishable foods, and thus is preferable.

The fine porous material used in the present invention is Otani stone having low molecular gas adsorption performance such as ethylene, zeolite, fine porous material or ceramic mainly composed of SiO ₂ such as cristobalite or silicate clay (particularly, fine pores). The diameter of 2 to 2800 angstroms is preferable), preferably 200 to 3
It was crushed to 00 mesh and dried. If necessary, add a small amount of metal oxides such as TiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, Na ₂ O, etc. to make a kneaded clay and make it into an appropriate size shape. After granulating, shaping and pre-drying at a temperature of about 100 ° C, sintering is performed at a temperature of 200 ° C to 900 ° C. Further, the sintered product may be irradiated with electromagnetic waves, or may be passed through an ozone atmosphere to be subjected to appropriate oxygen treatment.

These microporous materials are modified by contact with fatty acids or their derivatives. The fine porous material is preferably preliminarily contacted with a fatty acid or a derivative thereof to be pretreated for modification, but the fatty acid or a derivative thereof may be directly mixed with a thermoplastic resin under heating without pretreatment. . The fatty acid or its derivative is 0.1 to 50 parts by weight, preferably 0.5 to 100 parts by weight of the thermoplastic resin.
-10 parts by weight are used. The fatty acid or its derivative is
Each can be used alone or as a mixture thereof.

Examples of the fatty acid and its derivative include saturated and unsaturated fatty acids and their fatty acid esters, fatty acid glycerides, sorbitan fatty acids, fatty acid phosphoric acid esters, fatty acid alcohols and fatty acid amides, and preferably capric acid, lauric acid, myristin. Acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, hydroxystearic acid, n-butyl stearate, stearic acid glyceride, hydroxystearic acid triglyceride, stearic acid monoamide, stearic acid bisamide, Hydroxystearic acid bisamide, hydroxystearic acid ethylenebisamide, lauric acid amide, palmitic acid amide, behenic acid amide, lauric acid amide, oleic acid amide, erucic acid amide De, ricinoleic acid amide, lithium stearate, lithium hydroxy stearate, hydroxystearic calcium phosphate and the like.

As in the previous method, the thermoplastic resin is mixed with a fine porous material modified with a fatty acid or a derivative thereof, or a fatty acid or a derivative thereof and an unmodified fine porous material are mixed with a mixing device such as a super mixer. The resin composition of the present invention in which the fine porous material is compatibilly dispersed in the thermoplastic resin is prepared by stirring and mixing under heating.
In this case, the temperature of the mixing device is generally 50 to 170.
C. is preferred.

It is optional to add a stabilizer, an antioxidant, an ultraviolet absorber, a colorant, a plasticizer and the like, which are generally used as thermoplastic resin molded articles, as an additive material to the resin composition of the present invention.

The resin composition of the present invention is preferable because a high freshness-retaining effect can be obtained by the interaction between the added antibacterial / bactericidal substance and the microporous material, and particularly the action of suppressing the browning phenomenon such as lettuce and cabbage. Have.

Examples of the antibacterial / sterilized products include mustard powder and its extracted oil, Phynchitto and its allyl isothiocyanate, J-shaped oil and its component eugenol,
In addition to tannin, tannic acid, sibuol, and the like, natural products containing the above components can be mentioned.

These antibacterial / sterilized products are preferably contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the thermoplastic resin.

In the resin composition of the present invention, the compounding amount of the fine porous material can be arbitrarily set with respect to the thermoplastic resin,
In general, it is preferable to add 10 to 100 parts by weight of the fine porous material to 100 parts by weight of the thermoplastic resin. When the content of the fine porous material is 10 parts by weight or less, the effect of adsorbing low molecular gas such as ethylene becomes small, and when it is 100 parts by weight or more, moldability and strength are deteriorated, which is not preferable.

Various molded articles can be produced using the resin composition of the present invention, and not only films and sheets, but also tray-type packaging containers or containers suitable for fresh food applications using sheet-shaped molded articles. It can also be molded into a container or the like. Further, when molded into a sheet or container having a thickness of 200 μ or more, preferably 400 μ or more, a fine porous material can be contained more than the conventional film (for example, 20 parts by weight of the fine porous material with respect to the thermoplastic resin). As described above, it is possible to provide a molded product suitable for fresh food products.

Therefore, in the case of a molded product, one mode of its production will be described. Kneading the thermoplastic resin composition of the present invention obtained as described above in an extruder held at a predetermined temperature, and It can be manufactured into a predetermined molded product by any one of a T-die held at a predetermined temperature, a calendar roll, an injection molding machine and the like. In this case, instead of the extruder,
It is also possible to knead with a mixing roll kept at a predetermined temperature.

Here, the heating temperature of the extruder, the calender roll, and the injection molding machine is appropriately determined depending on the kind of the thermoplastic resin as the raw material, the mixing ratio of each component, etc., but is generally 10
It is between 0 ° C and 300 ° C.

The sheet thus obtained can be processed into a desired shape, for example, a packaging container, by a known method.

Action The molded product produced from the resin composition of the present invention dramatically maintains the freshness of fresh foods such as fruits and vegetables and fresh animal foods for a long time because the resin composition and Otani stone, fine particles of zeolite, etc. Adsorption, deodorization, dehumidification effect of ethylene gas due to the adsorption effect of the porous material, and characteristics such as ethylene gas permeability and moisture vapor suppression to prevent water droplets from adhering to the surface and Due to the interaction of.

Further, as the fine porous material, when the one treated with electromagnetic waves or ozone and subjected to oxygen treatment is used, it is considered that ethylene gas is changed to ethylene oxide by its oxidation catalytic action, Not only does it delay the ripening of fruits, but also prevents the deterioration of fresh food products such as fruits and vegetables, fresh animal foods and paste products by the synergistic effect of this and the antibacterial action of ethylene oxide.

These effects are similarly exhibited not only when the resin composition of the present invention is molded into a packaging container, but also when the resin composition or sheet is placed inside, for example, a commercially available cardboard box.

Example 1 1 part by weight of palmitic acid, 25 parts by weight of zeolite powder (<200 mesh) and 5 parts by weight of mustard were mixed and brought into contact with each other, and 100 parts by weight of polystyrene in the form of pellets were then mixed in a super mixer at about 120 ° C. The mixture was stirred and mixed in to obtain a resin composition having a structure in which zeolite powder was scattered in the thermoplastic resin phase.

The obtained resin composition was supplied to a hopper of an extruder (single shaft) equipped with a T-die equipped with a dullage type screw via a loader device, kneaded, and extruded from the die.

The shape of the screw is assumed to be constant at the tip after the groove depth is gradually reduced from the root to the tip so that the kneading effect can be improved, and the waviness due to the instantaneous fluctuation of the pressure. The ratio L / D of the length to the diameter is set to 22 in order to reduce the occurrence of heat generation and facilitate temperature control.
Further, the temperature was set to be 190 ° C to 200 ° C at the cylinder.

The extrusion die used was a fish tail type, which is effective for producing thick sheets, and was extruded as a sheet having a thickness of 0.4 mm by controlling the temperature distribution of the die.

After cooling this extruded sheet, in order to give gloss, while sandwiching it between two hollow rolls that have been plated with chromium that can be moved vertically by an air cylinder,
The sheet was wound into a roll at a uniform speed from the die while applying an appropriate tension to the sheet by a take-up roll made of an iron roll.

In addition, this roll has a fixed thermometer to bring the temperature to 80 ° C by circulating hot water whose temperature is precisely controlled, and a pressing pressure of 3 kg with an air cylinder.
It was controlled to be / cm ² . As a result, a sheet in which zeolite was uniformly dispersed in styrene could be obtained.

Example 2 The sheet obtained in Example 1 was vacuum-formed to prepare a tray containing fine porosity (size: 190 mm × 105 mm × 28 mm).

On the other hand, a tray of similar shape was made from a conventional high-impact styrene resin sheet having a thickness of 0.4 mm.

80 g of cut vegetables was put in each of the trays, and both of them were attached with the same vinyl chloride anti-fog type lids and stored at room temperature.

The latter started to brown in 1 day, while the former was 1 more than the latter.
Since the browning started after ~ 2 days, it was found that the former is superior in the effect of preventing browning of vegetables.

EFFECT OF THE INVENTION The resin composition of the present invention can optionally contain a fine porous material over a wide range from a low content to a high content. It is possible to provide a resin molded product containing a large amount of the fine porous material. Therefore, the content can be changed according to the object of fresh food such as fruits and vegetables, fresh animal food, and the like, and the freshness maintenance period can be dramatically increased according to each application.

In particular, the resin composition of the present invention molded into a sheet can contain a large amount of a low-molecular-gas-adsorbing fine porous material, and is a tray-type packaging container which is the current mainstream packaging form. It can be molded into various shapes and is suitable for long-distance transportation and maintenance of freshness in stores, and is useful in providing various molded products excellent in terms of transportation, display, quality and the like. By combining this sheet with cardboard, shipment adjustment of agricultural products such as mandarin oranges and spinach,
It is possible to provide a composite container having an excellent effect on long-distance transportation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08K 7/22 KCL 7242-4J 9/04 KCP 7242-4J 11/00 KCR 7242-4J

Claims (6)

[Claims] 1. An essential component is a fatty acid, a hydroxylated fatty acid, an inorganic salt of a fatty acid, an inorganic salt of a hydroxylated fatty acid, a fatty acid glyceride, a hydroxylated fatty acid glyceride, a fatty acid amide, a hydroxylated fatty acid amide, a fatty acid ester, a fatty acid phosphate ester. A thermoplastic resin composition for maintaining the freshness of a fresh food product, which comprises a fine porous material modified with sorbitan fatty acid and / or fatty acid alcohol and having a low molecular gas adsorption capacity, a thermoplastic resin, and an antibacterial / sterilized product. 2. The thermoplastic resin composition for maintaining the freshness of fresh foods according to claim 1, wherein the fine porous material is contained in an amount of 100 parts by weight or less based on 100 parts by weight of the thermoplastic resin. 3. A fatty acid, a hydroxylated fatty acid, an inorganic salt of a fatty acid,
Inorganic salt of hydroxy fatty acid, fatty acid glyceride, hydroxy fatty acid glyceride, fatty acid amide, hydroxy fatty acid amide, fatty acid ester, fatty acid phosphate ester, sorbitan fatty acid and / or fine porous material having low molecular gas adsorption ability A method for producing a thermoplastic resin composition for maintaining the freshness of a perishable food product, which comprises stirring and mixing a thermoplastic resin and an antibacterial / sterilized product under heating with modification. 4. An essential component is a fatty acid, a hydroxylated fatty acid, an inorganic salt of a fatty acid, an inorganic salt of a hydroxylated fatty acid, a fatty acid glyceride, a hydroxylated fatty acid glyceride, a fatty acid amide, a hydroxylated fatty acid amide, a fatty acid ester, a fatty acid phosphate ester. Of fresh food products formed by molding a thermoplastic resin composition comprising a microporous material modified with sorbitan fatty acid and / or fatty acid alcohol and having a low molecular gas adsorption capacity, a thermoplastic resin, and an antibacterial / sterilizing material Molded resin products for use. 5. The resin molded product is a sheet.
A molded resin product for maintaining the freshness of the perishable food according to the item. 6. A fatty acid, a hydroxylated fatty acid, an inorganic salt of a fatty acid,
Inorganic salt of hydroxy fatty acid, fatty acid glyceride, hydroxy fatty acid glyceride, fatty acid amide, hydroxy fatty acid amide, fatty acid ester, fatty acid phosphate ester, sorbitan fatty acid and / or fine porous material having low molecular gas adsorption ability A method for producing a molded resin product for maintaining the freshness of a fresh food product, in which a thermoplastic resin and an antibacterial / sterilized product are stirred and mixed while being modified, and then kneaded by an extruder and further molded.