JP2001179090A - Oxygen absorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material which can be used for a container, a packaging material or a deoxidizing agent and has outstanding oxygen absorbing performance. SOLUTION: The oxygen absorbing material is composed of a composition containing 70 wt.% or more of a methaxylylene diamineadipate unit as a repeating unit and a resin component with a melt point of 230 deg.C or below and a metal catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an oxygen-absorbing material having excellent oxygen-absorbing properties. This one is
It can be used for all or a part of the container body, lid, packaging bag, etc., and can also function as an oxygen scavenger by being present in a container or bag in the form of a sheet or powder.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open Publication No. Hei 2-500846 and Japanese Patent Laid-Open Publication No. Hei 3-762, one of packaged materials is disclosed.
It is known to use an oxidizable polymer partially or wholly containing a small amount of a transition metal compound catalyst to capture oxygen molecules by an oxygen oxidation reaction. Specifically, polyamide (MXD6) obtained by polycondensation of meta-xylylenediamine (MXD) and adipic acid is used to stabilize the storage of oxygen-sensitive substances (food, beverages, pharmaceuticals, precision electronic parts, etc.). Available. In particular, recently, there is an increasing expectation of practical use as an application to the conversion of beer containers into plastic bottles. However, a polymer material that can more efficiently absorb oxygen is desired in order to make the bottle container both taste and economically better.

[0003]

In view of such circumstances, the present invention aims to utilize oxygen-sensitive substances for preservation and stabilization, and in particular, to prevent the taste of beverages and foods such as beer from being changed by the oxygen oxidation reaction. The purpose of the present invention is to provide a polymer material having an oxygen absorbing ability higher than ever before so that it can be stored for a long period of time.

[0004]

Means for Solving the Problems The present inventors have conducted extensive studies on the oxygen absorption performance of the MXD6 system. As a result, in the MXD6, the MXD6 oxygen oxidation reaction that captures oxygen molecules occurs preferentially in the amorphous portion. It was found that the reaction progressed very slowly in the crystal part. From this finding,
By incorporating a copolymer component that reduces the crystallinity of MXD6, a polymer material having better oxygen absorption performance than a conventional MXD6-based oxygen absorbent could be obtained.

That is, the present invention provides an oxygen-absorbing material comprising a resin composition containing a resin component and a metal catalyst,
The resin component is at least one kind of a resin having a melting point of 230 ° C. or less or a resin blend having a melting point of 230 ° C. or less, and contains 50% by weight or more of a metaxylylenediamine adipate unit. Oxygen absorbing material. When the melting point is 230 ° C. or lower, a clear melting point may not be exhibited, but this case is also included in the scope of the present invention.

[Detailed Description of the Invention] In MXD6, it has been found that the oxygen absorption function is advanced by the oxidation reaction of the methylene group in the meta-xylylene group. Therefore, basically, an oxygen-absorbing material having more meta-xylylenediamine adipate structures can absorb more oxygen. However, as described above, the oxygen absorption rate can be increased by increasing the amorphous portion of MXD6, which can be said to be important as the performance as an oxygen absorbent.

The melting point of MXD6 is usually 240 ° C. or higher, and the crystal part occupies a large part. For example, by copolymerizing other components or blending another resin,
The amorphous portion can be increased. Furthermore, the amorphous portion M
Crystallization of XD6 can be suppressed, and stable oxygen absorption performance can be obtained. The melting point of the resin component is lowered by copolymerizing another component or blending another resin. In the present invention, the melting point of the resin component is 230
C. or lower, preferably 225.degree. C. or lower, more preferably 220.degree. C. or lower.

The structure which can be used with meta-xylylenediamine adipate units can be incorporated as a copolymer component into a polyamide comprising meta-xylylenediamine and adipic acid. Examples of diamines that can be copolymerized include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, heptamethylenediamine, and octamethylene. Aliphatic diamines such as diamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, hexadecamethylenediamine, octadecamethylenediamine, cyclohexanediamine, 1,3-bisaminomethyl Cyclohexane, bis-
Alicyclic diamines such as (4,4'-aminocyclohexyl) methane, cyclohexanediamine, methylcyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, and aromatic diamines such as paraxylylenediamine; Can be

As the dicarboxylic acid component, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandionic acid, dodecandionic acid, tridecadionic acid, tetradecadionic acid, hexadecadionic acid, hexadecene Diacids, octadecadionic acid, octadecenedioic acid, eicosandioic acid, eicosenedioic acid, docosandioic acid, aliphatic dicarboxylic acids such as 3,2,4-trimethyladipic acid and 1,4-cyclohexanedicarboxylic acid Such alicyclic dicarboxylic acids, terephthalic acid, isophthalic acid, phthalic acid, xylylene dicarboxylic acid, aromatic dicarboxylic acids such as naphthalenedicarboxylic acid and the like can be mentioned. Furthermore, it is also possible to form a copolymer polyamide with lactams such as ε-caprolactam and laurolactam and amino acids such as aminohexanoic acid and aminoundecanoic acid. Further, a polyesteramide structure can be obtained by combining a diol such as ethylene glycol, butanediol, hexanediol, octanediol, nonanediol, decanediol, diethylene glycol, triethylene glycol, polyethylene glycol, or tetramethylene glycol with dicarboxylic acids. . A copolymer structure having another structure may be used, but in order to exhibit the excellent oxygen absorption performance as described above, it is necessary to contain 50% by weight or more of a metaxylylenediamine adipate unit as a repeating unit.
If the meta-xylylenediamine adipate unit is at most 50% by weight, it will not be possible to obtain a sufficient oxygen absorption rate. The content of the metaxylylenediamine adipate unit is preferably at least 60% by weight, more preferably at least 70% by weight.

The resin component containing 50% by weight or more of metaxylylenediamine adipate unit may be a blend of MXD6 polymer and another polymer in addition to the above-mentioned copolymer. As the polymer to be blended, another polyamide having a good affinity for the MXD6 polymer is suitable. Specific examples include polycaprolactam (nylon 6) and polylaurolactam (nylon 1).
2), polyhexamethylene adipamide (nylon 6,
6), polyhexamethyleneazeramide (nylon 6,
9), polyhexamethylene sebacamide (nylon 6,1
0), aliphatic polyamides such as polyhexamethylene dodecanoamide (nylon 6, 12), alicyclic polyamides such as polyamide of 1,3-bis (aminomethyl) cyclohexane and aliphatic dicarboxylic acid, polyhexamethylene terephthalate Examples include aromatic polyamides such as phthalamide (nylon 6, T), polyhexamethylene isophthalamide (nylon 6, I), and polyphenylene phthalamide, nylon 12-based elastomer, polyetheresteramide, and polyether polyamide. Further, in addition to these homopolymers, it is also possible to mix them as a polymer mixture. Furthermore, the object can be achieved by blending another resin, for example, polyester, polyolefin, polyvinyl alcohol, or the like, as long as the oxygen absorption characteristics are not significantly changed.

By the copolymerization or polymer blending described above, the melting point of the obtained resin component is 230 ° C. or less, and at least 70% by weight of meta-xylylenediamine adipate unit is included, so that excellent oxygen absorption characteristics can be obtained. Can be obtained.

The metal catalyst used in the present invention has an atomic number of 2
Those containing up to 9 transition metals, cobalt and rhodium are particularly useful, and include organic acid salts of metal ions, acetylacetonate complexes, phthalocyanine complexes, monoalkyl phosphate ester salts, dialkyl phosphate ester salts, and aryl phosphate ester salts. , Polyacrylate, ethylene acrylate copolymer salt, benzoate and the like.

The metal catalyst in the present invention is added to the polymer material alone or as a mixture. The addition amount is not particularly limited, but is preferably 0.001% by weight to 10% by weight based on the polymer. If the amount is small, the oxygen absorption performance cannot be improved. If the addition amount is too large, improvement in oxygen absorption performance is not seen, and problems in molding processing are likely to occur.

[0014]

[Examples] Melting point measurement of resin by DSC showed 5 mg of resin.
Was measured at a heating rate of 20 ° C./min by DSC7 from Perkin-Elmer, and the melting peak temperature was taken as the melting point.

For measuring the oxygen absorption rate, a 1 cm square measurement film was placed in a glass container having an open mouth, immersed in a water bath set at 50 ° C., and left for 72 hours. A part of the sample was deuterated formic acid / deuterated chloroform (4 /
1) and dissolved at 50 ° C. at Varian Unity
H-NMR measurements were performed using a -500 NMR spectrometer. The amount of oxygen absorption was determined from the decrease in the signal of the methylene proton of the meta-xylylenediamine unit (6.8 pp).
4-4.5 with respect to signal intensity of proton on aromatic ring of meta-xylylenediamine unit appearing at m-8 ppm
The ratio of the methylene signal intensity of the metaxylylenediamine unit appearing in ppm determines the signal amount of the methylene proton of the metaxylylenediamine unit).

Example 1 Metaxylylenediamine, adipic acid, and sebacic acid were charged at a molar ratio of 100: 90: 10 to synthesize a copolymerized polyamide. The melting point by DSC was 219 ° C. 1 mol% of cobalt acetate was mixed with the obtained copolymerized polyamide, and pelletized by an extruder set at 270 ° C. The pellet is 270
The film was formed into a film having a thickness of about 40 μm by a heat press machine set at a temperature of ° C. The decrease in methylene signal in the oxygen absorption rate measurement performed by the above method was 17%.

Example 2 Metaxylylenediamine, decamethylenediamine and adipic acid were mixed at 90: 10: 100.
The same evaluation as in Example 1 was performed using a copolymerized polyamide prepared by mixing at a molar ratio of Melting point 217 ° C,
The decrease in methylene signal in the oxygen absorption rate measurement was 1
5%.

Example 3 Commercially available MXD6 (Tyobo T
600) and a copolyamide synthesized by charging metaxylylenediamine, adipic acid, and sebacic acid in a molar ratio of 100: 50: 50, and mixing them at a weight ratio of 2: 1. The mixture is heated to 270 ° C. with 1 mol% of cobalt acetate. It was formed into a film having a thickness of about 40 μm by the set heat press machine. When the same evaluation as in Example 1 was performed, no clear melting point was recognized, and the amount of reduction of the methylene signal in the oxygen absorption rate measurement was 15%.

Comparative Example 1 Commercially available MXD6 (T
600), and the same evaluations as in Example 1 were performed. The melting point was 244 ° C., and the decrease in methylene signal in oxygen absorption rate measurement was 11%. Comparative Example 2 The same evaluation as in Example 1 was performed using a copolymer polyamide synthesized by charging metaxylylenediamine, adipic acid, and sebacic acid at a molar ratio of 100: 95: 5. The melting point was 233 ° C., and the decrease in methylene signal in oxygen absorption rate measurement was 12%. Comparative Example 3 Example 1 was performed using a copolymer polyamide synthesized by charging metaxylylenediamine, hexamethylenediamine, and adipic acid at a molar ratio of 60: 40: 100.
The same evaluation was performed. Although no clear melting point was shown by DSC, the decrease in methylene signal in oxygen absorption rate measurement was 10%.

[0020]

As can be seen from the above results, the resin composition of the present invention can be used as a material having higher oxygen absorption performance than polymetaxylylene adipamide, which is known as an oxygen-absorbing resin, in containers and packaging. It can be said that it is a resin that can be used alone or in a laminated form as a material for bag use, and is also useful as an oxygen scavenger present in a container or bag.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Matsuda 10-24 Toyocho, Tsuruga-shi, Fukui Toyobo Co., Ltd. Tsuruga Plant (72) Inventor Shoichi Katamai 2-chome Katata, Otsu-shi, Shiga No. 1 Toyobo Co., Ltd. Research Laboratory (72) Inventor Hisashi Hisahara 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. Research Laboratory F-term (reference) 3E067 AA03 AA11 AB01 AB26 AB97 BA03A BB22A BB25A EE25 EE32 GB13 GD02 4G066 AB23B AC11C AC26C BA03 BA38 CA37 EA07 FA07 FA27 FA37 4J002 BB232 BG012 CL031 EE046 EG046 EG076 ET006 EW046 FD202 FD206 GF00 GG01 GG02

Claims (1)

[Claims] 1. An oxygen-absorbing material comprising a resin composition containing a resin component and a metal catalyst, wherein the resin component is a resin having a melting point of 230 ° C. or lower or a resin blend having a melting point of 230 ° C. or lower. And at least one of the above, and 50 units of meta-xylylenediamine adipate
An oxygen-absorbing material, characterized in that it contains at least% by weight.