Oxygen-absorbing resin composition

Abstract

An oxygen-absorbing resin composition copolymerized polyolefin compound including a copolymerized polyolefin compound and a transition metal catalyst, wherein the copolymerized polyolefin compound is a copolymerized polyolefin compound including at least one of constitutional unit (a) selected from the group consisting of the constitutional units represented by the general formula (1), and at least one of the constitutional unit (b) having an indane ring, selected from the group consisting of the constitutional units represented by the general formulas (2) and (3).

Claims

1. An oxygen-absorbing resin composition comprising a copolymerized compound and a transition metal catalyst, wherein the copolymerized compound is a copolymerized compound comprising: at least one of constitutional unit (a) selected from the group consisting of the constitutional units represented by the following general formula (1): ##STR00008## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each independently represent a hydrogen atom or a first monovalent substituent, the first monovalent substituent is at least one selected from the group consisting of a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxy group, a carboxyl group, an ester group, an amide group, a nitro group, an alkoxy group, an aryloxy group, an acyl group, an amino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclic thio group and an imide group, and these groups may further have a substituent; and at least one of constitutional unit (b) having an indane ring, selected from the group consisting of the constitutional units represented by the following general formulas (2) and (3): ##STR00009## wherein R.sub.5, R.sub.6 and R.sub.7 each independently represent a hydrogen atom or a second monovalent substituent, R.sub.8, R.sub.9, R.sub.10 and R.sub.11 each independently represent a third monovalent substituent, the second monovalent substituent and the third monovalent substituent are each independently at least one selected from the group consisting of a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxy group, a carboxyl group, an ester group, an amide group, a nitro group, an alkoxy group, an aryloxy group, an acyl group, an amino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclic thio group and an imide group, the groups may further have a substituent, and when the number of R.sub.8s, R.sub.9s, R.sub.10s or R.sub.11s being present is two or more, the two or more R.sub.8s, R.sub.9s, R.sub.10s or R.sub.11s may be the same as each other or different from each other; m represents an integer of 0 to 3, n represents an integer of 0 to 5, q represents an integer of 0 to 4 and q represent an integer of 0 to 4, and at least one hydrogen atom is bonded to a benzylic position of the indane ring; X represents a divalent group selected from the group consisting of (CO)O, (CO)NH, O(CO), NH(CO) and (CHR)s-, and s represents an integer of 0 to 12; Y is (CHR)t-, and t represents an integer of 0 to 12; and R represents a monovalent chemical species selected from the group consisting of a hydrogen atom, a methyl group and an ethyl group.

2. The oxygen-absorbing resin composition according to claim 1, wherein the transition metal catalyst comprises at least one transition metal selected from the group consisting of manganese, iron, cobalt, nickel and copper.

3. The oxygen-absorbing resin composition according to claim 1, wherein the transition metal catalyst is included in an amount of 0.001 to 10 parts by mass in terms of the transition metal amount, based on 100 parts by mass of the copolymerized compound.

4. The oxygen-absorbing resin composition according to claim 1, wherein a content ratio of a content of the constitutional unit (a) to a content of the constitutional unit (b) is 1/99 to 99/1 in terms of the molar ratio.

5. The oxygen-absorbing resin composition according to claim 1, wherein the constitutional unit (a) is at least one selected from the group consisting of the constitutional units represented by the following general formulas (4) and (5): ##STR00010## and the constitutional unit (b) is the constitutional unit represented by the following general formula (6): ##STR00011##

Description

EXAMPLES

(1) The present invention is described in more detail, with reference to Examples and Comparative Examples presented below, but the present invention is not limited at all by following Examples.

(2) The measurements of the amount of oxygen absorbed, and the evaluations of the exterior appearance and odor were performed as follows.

(3) (1) Measurement of Amount of Oxygen Absorbed

(4) Two pieces of a film were packed respectively, together with 500 cc of air, in two gas barrier bags each formed of an aluminum foil laminate film, wherein the relative humidities in the bags were 100% and 30%, respectively; the two bags were sealed after packing, and stored at 23 C.; then, the total amount of oxygen absorbed in three days after the sealing in each of the bags was measured.

(5) (2) Exterior Appearance

(6) The exterior appearance of a film after a storage at 40 C. and a relative humidity of 100% for 1 month was visually verified.

(7) (3) Evaluation of Odor

(8) In the same manner as in the measurement of the oxygen absorption amount, a sealed bag stored at a temperature of 23 C. and a relative humidity of 100% or 30% was opened, and the odor in the sealed bag was verified.

(9) The occurrence or nonoccurrence of the change of the odor before and after the oxygen absorption were evaluated, and the case where no change of the odor was found after the oxygen absorption was determined to be the case of no generation of the odor.

Synthesis Example

(10) In a four-necked separable flask having an internal volume of 1000 mL, 100 g of an ethylene-methyl methacrylate copolymer (Acryft WK402, trade name, MMA content: 25% by weight, manufactured by Sumitomo Chemical Co., Ltd.), 84 g of 2-hydroxyhydrindene, 150 g of decalin and 0.2 g of tetrabutyl titanate as a transesterification catalyst were charged; the resulting reaction solution was increased in temperature to 210 C. under stirring in a nitrogen atmosphere, and was allowed to react for 3 hours while methanol was being distilled off. After the completion of the distillation off of methanol, the pressure of the reaction system was gradually reduced and decalin was distilled off. Subsequently, the obtained crude reaction product was dissolved in toluene heated to 80 C. so as for the concentration to be 3 to 4% by weight, then the resulting solution was cooled to about 40 C., methanol was added to the solution, and the reprecipitated indane ring-containing copolymerized polyolefin compound was collected by filtration. The analysis results of the copolymerized polyolefin compound by NMR are as follows:

(11) .sup.1H-NMR (400 MHz CDCl.sub.3) 2-hydroxyhydrindene region: 7.16-7.22 (4H m), 5.49-5.51 (1H m), 2.94-2.98 (2H dd), 3.28-3.33 (2H dd), methyl methacrylate region: 3.65 (3H s)

(12) The weight average molecular weight and the number average molecular weight of the obtained copolymerized polyolefin compound were measured by GPC (gel permeation chromatography), and the weight average molecular weight was found to be 1.110.sup.5, and the number average molecular weight was found to be 3.710.sup.4. The melting point of the obtained copolymerized polyolefin compound was measured by DSC, and was found to be 72 C.

Example 1

(13) Cobalt stearate was dry blended with the copolymerized polyolefin compound in an amount of 0.1 part by mass based on 100 parts by mass of the copolymerized polyolefin compound. From the resulting blend, an oxygen-absorbing film of 130 mm in width and 90 to 100 m in thickness was prepared with a twin screw extruder having two screws of 20 mm in diameter, under the conditions of an extrusion temperature of 220 C., a screw rotation number of 60 rpm, a feed screw rotation number of 16 rpm, and a taking-up speed of 1.0 m/min. From the obtained film, a 100 mm100 mm film was prepared, and was used for the evaluations of the amount of oxygen absorbed, the exterior appearance and the odor. The results thus obtained are shown in Table 1.

Example 2

(14) A film was prepared in the same manner as in Example 1 except that cobalt stearate was replaced with iron stearate, and was used for the evaluations of the amount of oxygen absorbed, the exterior appearance and the odor. The results thus obtained are shown in Table 1.

Comparative Examples 1

(15) A film was prepared in the same manner as in Example 1 except that the copolymerized polyolefin compound was replaced with N-MXD6 (trade name MX nylon S6011, manufactured by Mitsubishi Gas Chemical Company, Inc.), and was used for the evaluations of the amount of oxygen absorbed, the exterior appearance and the odor. The results thus obtained are shown in Table 1.

(16) TABLE-US-00001 TABLE 1 Amount of Transition oxygen absorbed.sup.1) Odor generation Resin metal Humidity Humidity Exterior Humidity Humidity compound catalyst 100% 30% appearance.sup.2) 100% 30% Example 1 Copolymerized Cobalt 14 cc 20 cc Shape None None polyolefin stearate retained Example 2 Copolymerized Iron 10 cc 14 cc Shape None None polyolefin stearate retained Comparative N-MXD6 Cobalt 3 cc 0 cc Collapsed None None Example 1 stearate 1) Total amount of oxygen absorbed in 7 days from the start of the test. 2) Evaluated after the storage at 40 C. and a humidity of 100% for 1 month.

(17) As can be seen from Examples 1 and 2, the oxygen-absorbing resin composition of the present embodiment was free from the odor generation after oxygen absorption, and exhibited an excellent oxygen absorption performance at either a high humidity or a low humidity. The oxygen-absorbing resin composition of the present embodiment retained the shape of the film formed therefrom without undergoing collapse.