JPH03200875A - Synthetic resin container - Google Patents

Abstract

PURPOSE:To prepare the title container which shows a high adsorptivity against many odorous substances, can easily recover the adsorptivity after satd. adsorption, and is excellent in the safety by compounding a synthetic resin, a specific element, and aggregate particles of an oxide contg. Zn as the main component. CONSTITUTION:A synthetic resin (e.g. a linear low-density polyethylene), at least one element selected from the group consisting of Ti, Al, Mg, Ca, and Si, and aggregate particles of an oxide contg. Zn as the main component (e.g. aggregate particles of ZnO.TiO2.H2O) are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a synthetic resin container that has excellent deodorizing properties and does not leave behind odors of fresh foods such as fish and shellfish, meat, and vegetables and processed foods.

<Prior art> In recent years, various types of deodorizers have been developed with the aim of creating a comfortable environment by removing various malodorous gases such as hydrogen sulfide, ammonia, mercaptans, amines, and aldehydes that are generated in daily life. There is. Resin compositions containing these have also been published, but when used as containers for food packaging, it is desired that at least the following conditions be satisfied.

(1) It does not leave behind the odors of various odorous substances generated by a wide variety of foods in the container, has good adsorption performance, and has a connected effect.

(2) It must be highly safe.

(3) Even after reaching a saturated adsorption state, the adsorption performance can be easily restored by operations such as heating or washing with water.

(4) Withstands the molding temperature of synthetic resin and is resistant to discoloration;
Use a deodorizing agent that does not accelerate the deterioration of the resin.

(5) Good appearance and easy coloring.

<Problems to be Solved by the Invention> However, until now, there has been no synthetic resin container that fully satisfies all of the above conditions, and no synthetic resin container has been developed through recent research.

For example, activated carbon, which is most commonly used as a deodorizing agent, has an excellent deodorizing effect on malodorous gases such as mercaptans and amines, but has poor deodorizing properties against hydrogen sulfide and ammonia. In order to improve this point, a product called impregnated carbon, in which activated carbon is loaded with acid, alkali, or a certain type of halide, is also produced, but products that have undergone such treatment may not contain the acid or alkali itself. Similarly, it is not suitable for use as a food container because it must be treated as a type of hazardous material. In addition, an essential drawback of activated carbon is that it is black, and because of this color, it cannot be used in synthetic resin containers other than black.

In addition, deodorants using ferrous sulfate are pe! +
is easily thermally oxidized and discolors quickly, and p e Z
It has been pointed out that + has the disadvantage of accelerating thermal deterioration of polyolefins, etc., and cannot be used for synthetic resin containers. Other deodorizing agents using organic acids have activity against basic gases such as ammonia and amines, but have little effect on acidic gases such as hydrogen sulfide and mercaptans.

Furthermore, deodorizing agents using sulfates such as alum (A j! K(SOa) z) are similarly active only against basic gases such as ammonia and amines, and are not effective against acidic gases.

Means for Solving the Problem> As a result of intensive research in view of the above situation, the present inventors have found that
A synthetic resin container containing a deodorizing agent made of oxide aggregate particles whose main components are zinc and one or more elements selected from the group consisting of titanium, aluminum, magnesium, calcium, and silicon is as described above. They found that there were no drawbacks and completed the present invention.

That is, the present invention contains a synthetic resin (A) and oxide aggregate particles (B) whose main components are zinc and one or more elements selected from titanium, aluminum, magnesium, calcium, and silicon. The present invention provides a synthetic resin container characterized by the following characteristics.

The synthetic resin (A) used in the present invention is not particularly limited, and includes, for example, polyethylene, polypropylene, polystyrene, polyamide, polyester, polyvinyl alcohol, polycarbonate, polyacetal,
Thermoplastic resins such as BS resin, acrylic resin, fluororesin, polyurethane elastomer polyester elastomer, thermosetting resin such as phenol resin, area resin, melamine resin, unsaturated polyester resin, epoxy resin, urethane resin, especially thermoplastic resin In particular, olefinic thermoplastic resins are preferred.

The method for producing the oxide aggregate particles (B) used in the present invention includes, for example, (1) zinc salt and one or more elements selected from the group consisting of titanium, aluminum, magnesium, calcium, and silicon (hereinafter referred to as "other"). A method of hydrolyzing a mixed aqueous solution of salts of metals (hereinafter referred to as metals) with an acid or alkaline aqueous solution to form a precipitate, separating and drying the precipitate. A method in which oxides of different metals are immersed under heating in an aqueous solution of zinc or other metal salts, and aqueous ammonia, etc. are added as necessary. (4) A method of reacting an aqueous solution of zinc salt with sodium silicate to perform ion exchange, etc. There are several manufacturing methods, and the manufacturing method (1) is particularly preferred, although it is not particularly limited.

To explain the manufacturing method in (1) above in more detail, an aqueous solution of a zinc salt and another metal salt, and an appropriate amount of an acid or alkaline aqueous solution are added simultaneously, and the pH of the combined solution is always 6 to 12. mixing and coalescing, controlling the temperature to be maintained within a range of After that, it is dried.

In the present invention, oxide aggregate particles containing zinc oxide and other metal oxides as main components in a molar ratio of 5=95 to 95:5 are usually used, but in particular, zinc oxide and titanium dioxide are used. 3nia to 7:3 molar ratio as main components, and zinc oxide and aluminum oxide and/or
Alternatively, those containing silicon oxide as a main component at a molar ratio of 4:6 to 9:l are preferable, and the latter aggregate particles are particularly preferable because their color is close to colorless and they have excellent stability and dispersibility in the resin. preferable.

Oxide aggregate particles contained in the synthetic resin container of the present invention (
The content of B) is usually in the range of 0.1 to 20% by weight, preferably 0.2 to 5% by weight. Content is 0.1% by weight
If it is less than 20% by weight, the deodorizing effect is insufficient, and even if it is added in an amount exceeding 20% by weight, the effect remains virtually unchanged, which is uneconomical.

Furthermore, various additives such as antioxidants, inorganic fillers, fatty acid ester waxes, polyethylene waxes, etc. may be added to the synthetic resin container of the present invention as needed.

In addition, as a method of improving the dispersibility of a deodorizing agent made of oxide aggregate particles in a synthetic resin, it is preferable to add an emulsion such as silicone, and if a coupling agent or the like is added, the deodorizing effect will be reduced. There is a fear.

When a thermoplastic resin is used as the synthetic resin (A), during molding, a thermoplastic resin composition containing 10 to 80% by weight of oxide aggregate particles is melt-kneaded and then pelletized into master patch pellets. It is preferable to use it together with a thermoplastic resin because it has excellent workability.

The method for producing master patch pellets involves, for example, adding oxide aggregate particles, a thermoplastic resin such as polyethylene or polypropylene as a carrier resin, and, if necessary, a dispersing agent such as polyethylene wax, fatty acid ester wax, or metal soap. After mixing, the mixture is melt-kneaded at a temperature equal to or higher than the softening point of the carrier resin, and further formed into pellets using a pelletizer or the like. In addition, when particularly dispersibility is required, it is preferable to knead the deodorizing agent and PE wax using a mixer such as a heated three-roll mixer.

Alternatively, instead of a masterbatch, a dry color may be prepared by mixing a deodorizer and a metal soap such as a stearate of a metal such as zinc, aluminum, magnesium, or calcium using a Henschel mixer or the like. The deodorant oxide aggregate particles are usually contained in an amount of 5 to 80% by weight. When the master patch pellets or dry color obtained in this way are mixed with thermoplastic resin and subjected to molding processing such as injection molding, blow molding, vacuum molding, compression molding, etc., food odor remains in the container. A synthetic resin container that is difficult to maintain can be obtained. Furthermore, even after this container reaches a saturated adsorption state with -degree foul-smelling gas,
It has the characteristic that the adsorption force is restored to its initial level by heating at a temperature of about 80°C to 100°C for 30 to 60 minutes.

Although there are no particular restrictions on the form of the container, it is suitable for use in plastic containers for household or commercial kitchens.

For example, airtight containers, lunch boxes, plates, cups, bottles, buckets,
etc. It goes without saying that the lid of a container with a lid is also a part of the container.

<Examples> Next, the present invention will be described in more detail based on Examples. However, these are merely illustrative, and the scope of the invention is not limited thereto.

Reference Example 1 (Oxide Aggregate Particles) Take 11 liters of pure water into a 51 beaker and heat to 60 ml while stirring.
Heated and held at °C. Next, titanium sulfate-zinc sulfate mixed acid aqueous solution 21 containing 79.90 g of Tie and 81.37 g of ZnO and ammonia aqueous solution were mixed together, taking care to maintain the pH of the combined solution at 7.5. They were simultaneously dropped into the pure water over a period of 30 minutes.

After filtering and washing the product, it was dried at 200'C for 3 hours and Z
nO・TiO□・H2O-based oxide aggregate particles ([) were produced. When this deodorizing agent (1) was examined by X-ray diffraction, it was found to be amorphous. Further, the molar ratio of zinc oxide and titanium dioxide was 1:1 according to chemical analysis.

Reference Example 2 (same as above) 51. Pure water iN was dispersed in a beaker and heated and maintained at a temperature of 60°C while stirring.

Next, separately prepared zinc sulfate containing 81.37 g as zinc oxide and 50.98 g as aluminum oxide was added.
Al5nium sulfate mixed aqueous solution 21 and ammonia aqueous solution were simultaneously dropped into the pure water over 30 minutes while being careful to maintain the PTI of the combined liquid at 7.5.

After filtering and washing the generated precipitate, it was dried at 120°C for 6 hours, and ZnO/Altos-based (molar ratio ZnO: AI!tO
Oxide aggregate particles (n) with z = 2: 3) were produced.

Reference example, 3 (same as above) 51 Collect 11 pieces of pure water in a beaker and raise the temperature to 6 while stirring.
The temperature was maintained at 0°C.

Next, a zinc chloride aqueous solution containing 122.05 g of zinc oxide and 25.4 g of aluminum oxide were prepared separately.
A mixed aqueous solution 11 of sodium aluminate and sodium hydroxide containing 9 g of sodium aluminate and sodium hydroxide is added to
They were simultaneously dropped into the pure water over a period of 30 minutes while being careful to maintain the same. After filtering and washing the generated precipitate, 120
ZnO/Altos system (molar ratio Z
nO: a7! Oxide aggregate particles (III) with zOs =6:l) were produced.

Reference Example 4 (same as above) Sodium aluminate aqueous solution as silicon oxide 30.0
Oxide aggregate particles (IV) of ZnO/Si0g system (molar ratio ZnO: 5iOt=3:I) were produced in exactly the same manner as in Reference Example 3, except that the sodium silicate aqueous solution containing 4g was used.

Reference example 5 51 Collect 11 pieces of pure water in a beaker and raise the temperature to 6 while stirring.
The temperature was maintained at 0°C.

Next, a separately prepared zinc chloride aqueous solution containing 81.37 g as zinc oxide and 50.98 g as aluminum oxide were added.
30 as sodium alkinate and silicon oxide containing g
．． A mixed aqueous solution 11 of sodium silicate aqueous solution containing 0.04 g and sodium hydroxide is added until the pH of the combined solution is 7.
．． 30 in the pure water, being careful to maintain 5
They were simultaneously dropped over a period of minutes. After filtering and washing the generated precipitate 1
Dry at 20°C for 6 hours to produce ZnO-5iOz ・^18
0. System (molar ratio ZnO・Aj!10.・5iOz=2
: l : l) Oxide aggregate particles (V) were produced.

Examples 1 to 5 Oxide aggregate particles (1), (n) obtained in Reference Examples 1 to 5,
(III), (IV) or (V) 1 kg and R-680 (
Ishihara Sangyo titanium oxide) 160g and Sunwax 16
1P [Polyethylene wax manufactured by Sanyo Chemical Industry Co., Ltd.]
After mixing 1.16 kg, the mixture was melt-kneaded using a heated triple roll at a temperature of about 130°C to obtain a roll base. Next, 2 kg of this roll base and 2 kg of 1014G [chain low density polyethylene manufactured by Idemitsu Petrochemical Co., Ltd.]
were mixed in a Henschel mixer, melt-kneaded using an extruder at a temperature of 170°C, and then shaped into pellets to create a white masterbatch. 10 pieces of this masterbatch
After mixing 90 parts of 1014G and 90 parts of 1014G, a box-shaped container with a wall thickness of 2.5 ms+ was produced using an injection molding machine at 180°C. All of these containers were bright white.

Cut out 20g of samples from each of these containers, place each in a 31 Tetra bag, seal it, and the air inside is 31! The bags were filled with air to give an initial concentration of 1100 pp, and the odor gas components listed in Table 1 were injected into separate Tetra bags using a microsyringe so that the initial concentration was 1100 pp. Two hours after the gas was injected, the gas concentration inside the Tetra bag was measured using a detection tube. The results are shown in Table 1.

Next, desorption regeneration by saturated adsorption and heat drying was repeated for the samples shown in Table 1, and the recovery rate of adsorption performance was examined. For saturated adsorption, a high concentration (10
00 ppm or more) and left until there was no change in concentration. Desorption and regeneration was performed by heating in a 90°C oven for 30 minutes. This adsorption regeneration operation is repeated 5 times each.
After repeating the test several times, the same measurements as in Table 1 were performed to determine the recovery rate of removal rate, and the results are summarized in Table 2.

Comparative Examples 1-2 A synthetic resin container was prepared in the same manner as in Example 1, except that natural zeolite (Comparative Example 1) and potassium aluminum sulfate (Comparative Example 2) were used instead of oxide aggregate particles (1). A similar test was then conducted.

The results are shown in Tables 1 and 2.

Comparative Example 3 A synthetic resin container was obtained in the same manner as in Example 1, except that the addition of a deodorizing agent was omitted, and then the same test was conducted. The results are shown in Tables 1 and 2.

Examples 6-8 Roll base 2k obtained in the same manner as Example 1.2 or 4
After mixing 2 kg of -5016 [polypropylene manufactured by Chisso Co., Ltd.] with Chisso Polypropylene and Chisso Polypropylene in a Henschel mixer, the mixture was melt-kneaded using an extruder at a temperature of 240'C, and then shaped into pellets to create a white masterbatch. did. 10 parts of this masterbatch and Chisso Polypro-50169
After mixing with 0 parts, a container with a thickness of 3 mm was created using an injection molding machine at 260°C. All of these containers were bright white.

Next, 40 g of samples were cut from each of these containers, and a test was conducted in the same manner as in Example 1 except that each sample was used. The results are shown in Tables 1 and 2.

/ 627 Test Example 1 Containers were actually made with the compositions of Example 4 and Comparative Examples 2.3, and the food items listed in Table 3 were left with holes for 2 days, then washed with water and the strength of the odor attached to the containers was determined. It was evaluated using a sensory test.

There were 10 monitors, and the average value was calculated based on the following 5-level odor intensity classification.

Odor intensity 0: No odor 1: Slight odor 2: Discernible odor 3: Easily detectable odor 4: Strong odor Table 3 <Effects of the invention> The container of the present invention has high adsorption to a wide range of odorous substances. It has the effect that it has activity and can easily regenerate its function to its initial level after reaching saturated adsorption. In addition, it is highly safe and has high utility value as a container that can be used repeatedly to store food, etc. Furthermore, since it is colorless or white, it has the advantage that it can be colored freely over a wide range.

Claims (1)

[Claims] 1. Oxide aggregate particles (B) whose main components are a synthetic resin (A), one or more elements selected from the group consisting of titanium, aluminum, magnesium, calcium, and silicon, and zinc. A synthetic resin container characterized by containing. 2. The synthetic resin container according to claim 1, wherein the synthetic resin (A) is a thermoplastic resin. 3. The synthetic resin container according to claim 1, wherein the synthetic resin (A) is an olefin thermoplastic resin. 4. The synthetic resin container according to claim 1, 2 or 3, wherein the oxide aggregate particles (B) contain zinc oxide and titanium dioxide as main components. 5. The molar ratio of zinc oxide and titanium dioxide is 3:7~
5. The synthetic resin container according to claim 4, having a ratio of 7:3. 6. The synthetic resin container according to claim 1, 2 or 3, wherein the oxide aggregate particles (B) mainly contain zinc oxide, aluminum oxide and/or silicon dioxide. 7. The synthetic resin container according to claim 6, wherein the molar ratio of zinc oxide to aluminum oxide and/or silicon dioxide is in the range of 4:6 to 9:1. 8. The synthetic resin container according to any one of claims 1 to 7, wherein the container is formed by injection molding. 9. The synthetic resin container according to any one of claims 1 to 7, wherein the container is formed by blow molding. 10. The synthetic resin container according to any one of claims 1 to 7, wherein the container is formed by vacuum forming. 11. The synthetic resin container according to any one of claims 1 to 7, wherein the container is compression molded. 12. The synthetic resin container according to any one of claims 1 to 11, wherein the container is a food container. 13. The synthetic resin container according to any one of claims 1 to 11, wherein the container is a kitchen container. 14. Any one of claims 1 to 7, wherein the container is a closed food container, lunch box, plate, cup, bottle, or bucket.
Synthetic resin containers described in .