JP2002241610A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer raw material which has an improved oxygen- absorbing property, can prevent the deterioration in the qualities of oxygen- sensitive substances such as drinks and foods due to oxygen, and thereby enables the preservation of the substances for long periods. SOLUTION: This polyamide resin composition comprising a polyamide resin and a transition metal compound is characterized by (a) containing m- xylylenediamine in an amount of >=40 mol.% in the diamine component of the polyamide resin, (b) containing carboxyl terminal groups(CEG) in the polyamide resin in an amount of >=50 meq/kg based on the polyamide resin composition, containing amino terminal groups(AEG) in the polyamide resin in an amount of <=30 meq/kg based on the polyamide resin composition, and having a carboxyl terminal group(CEG) amount/amino terminal group(AEG) amount ratio of >=2, and (c) containing a transition metal in a transition metal compound in an amount of 10 to 100,000 ppm based on the polyamide resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin composition having excellent oxygen absorption. The polyamide resin composition of the present invention can be used as a film or sheet having deoxidation properties, and can be used for all or a part of materials such as a container body, a lid, and a packaging bag. Further, the polyamide resin composition of the present invention can be used as an oxygen scavenger by being present in a container or bag in the form of pellets, powder, or plate.

[0002]

2. Description of the Related Art As a method for stabilizing the storage of oxygen-sensitive substances such as foods, beverages, pharmaceuticals, cosmetics, and precision electronic parts, a method disclosed in JP-A-2-500846 and JP-A-3-762 is disclosed. A method of capturing oxygen molecules by an oxygen oxidation reaction using an oxidizable polymer containing a transition metal compound catalyst is known. As an oxidizable polymer,
Specifically, m-xylylene adipamide, which is a polyamide of m-xylylenediamine and adipic acid, is disclosed.

[0003] However, when the above-mentioned polymer is used, there is a problem that the oxygen-absorbing property is insufficient, so that the quality of oxygen-sensitive substances such as drinks and foods deteriorates, and the taste becomes worse. Recently, there has been a demand for a polymer material which can prevent oxygen-sensitive substances such as drinks and foods from deteriorating in quality due to increasing interest in safety and health, and can be stored for a longer period of time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an oxygen-sensitive substance, such as a beverage or food, which has improved oxygen absorption and is made of oxygen. It is an object of the present invention to provide a polymer material which can prevent the quality of the polymer from deteriorating and therefore can be stored for a long time.

[0005]

The present inventors have conducted detailed studies on the mechanism of oxygen absorption of m-xylylene adipamide and found that the carboxyl end group (hereinafter referred to as CEG) in m-xylylene adipamide. ) And the amount of amino terminal groups (hereinafter, also referred to as AEG) and their ratio within a specific range, and by blending a specific amount of a transition metal, the oxygen oxidation reaction is promoted, and oxygen absorption is further improved. It has been found that the quality of oxygen-sensitive substances such as beverages and foods can be prevented from deteriorating, and that it can be stored for a longer period of time, thereby completing the present invention.

That is, the present invention provides a polyamide resin composition containing a polyamide resin and a transition metal compound, wherein: a) the diamine component of the polyamide resin contains at least 40 mol% of m-xylylenediamine; b) Carboxyl end groups (CE
G) The amount is 50 meq / kg in the polyamide resin composition.
As described above, the amino terminal group (AEG) in the polyamide resin
The amount is 30 meq / kg or less in the polyamide resin composition, and the carboxyl terminal group (CEG) amount / amino terminal group (AEG) amount in the polyamide resin is 2 or more; and c) transition of the transition metal compound. The polyamide resin composition wherein the amount of the metal is 10 to 100,000 ppm in the polyamide resin composition.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyamide resin composition of the present invention contains a polyamide resin and a transition metal compound.

[0008] The diamine component of the polyamide resin in the polyamide resin invention, m-
It is necessary to contain xylylenediamine (hereinafter also referred to as MXD) in an amount of 40 mol% or more. MXD amount is 40 mol%
If it is less than 10, the oxygen absorbency of the polyamide resin composition is significantly reduced. The preferred amount of MXD is 5% of the total diamine component.
It is 0 mol% or more, especially 60 mol% or more.

As the diamine component other than MXD, for example, ethylenediamine, 1,2-propylenediamine,
Aliphatic diamines such as trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine; cyclohexanediamine And alicyclic diamines such as bis (4-aminocyclohexyl) methane; and aromatic diamines such as p-xylylenediamine. Among these, ethylenediamine, 1,2-propylenediamine, hexamethylenediamine, and p-xylylenediamine are preferred. The above diamine components may be used alone or in combination of two or more at an arbitrary ratio. The diamine component is used in a range of less than 60 mol% of all the diamine components.

The dicarboxylic acid component of the polyamide resin in the present invention includes, for example, adipic acid, sebacic acid,
Aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecadionic acid, dodecandionic acid, dimer acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid Acids; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, xylylenedicarboxylic acid, and naphthalenedicarboxylic acid; Among these, adipic acid, sebacic acid, succinic acid, azelaic acid and isophthalic acid are preferred, and adipic acid, sebacic acid and isophthalic acid are more preferred. The above dicarboxylic acid components may be used alone or in combination of two or more at an arbitrary ratio. When two or more kinds are used in combination, it is preferable to combine adipic acid and / or sebacic acid with succinic acid, azelaic acid and / or isophthalic acid.

In addition to the above diamine component and dicarboxylic acid component, lactams such as ε-caprolactam and laurolactam; and aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid can also be used as the copolymerization component.

As the preferred polyamide resin in the present invention, specifically, m-xylylene adipamide (hereinafter referred to as MX) obtained from m-xylylenediamine and adipic acid
D6), and m-xylylene sebacamide obtained from m-xylylenediamine and sebacic acid.
Further, a copolymer polyamide obtained from m-xylylenediamine and an acid component obtained by combining two or three kinds selected from adipic acid, sebacic acid and isophthalic acid at an arbitrary ratio is also preferable.

The amounts of the carboxyl groups and amino groups which are the terminal groups of the polyamide resin greatly affect the oxygen absorbency of the polyamide resin composition of the present invention. In the present invention, the amount of carboxyl terminal groups (CEG) in the polyamide resin is
In the polyamide resin composition, it is necessary to be 50 meq / kg or more. When the CEG amount is less than 50 meq / kg, the oxygen absorbency of the polyamide resin composition is significantly reduced. The preferred CEG amount is at least 60 meq / kg, particularly at least 70 meq / kg, in the polyamide resin composition. It is not clear how the amount of CEG affects the oxygen absorption of the polyamide resin composition. However, since the oxygen absorption of the polyamide resin composition increases remarkably as the CEG amount is 50 meq / kg or more and increases, CEG reacts with a transition metal compound described below, which acts as a catalyst, to form the transition metal compound. We believe that it may increase the catalytic activity and at the same time increase the solubility in the polyamide resin. Note that the CEG amount is preferably 250 meq / kg or less.

In the present invention, the amount of the amino terminal group (AEG) in the polyamide resin must be 30 meq / kg or less in the polyamide resin composition.
When the AEG amount exceeds 30 meq / kg, the oxygen absorbency of the polyamide resin composition is significantly reduced. The preferred amount of AEG is 25 meq / k in the polyamide resin composition.
g, especially 20 meq / kg or less. The effect of the amount of AEG on the oxygen absorbency of the polyamide resin composition is as follows:
As in the case of the EG, it is not clear yet. However, in practice, as the amount of AEG increases, the oxygen absorbency of the polyamide resin composition significantly decreases.
However, it is thought that the oxygen oxidation reaction by the catalytic action of a transition metal compound described later may be suppressed.

Further, the amount of CEG / AEG is also an important factor for the oxygen absorbency of the polyamide resin composition. In the present invention, it is necessary that the ratio of the CEG amount and the AEG amount in the polyamide resin, that is, the CEG amount / AEG amount is 2 or more. When the CEG amount / AEG amount is less than 2, the oxygen absorbency of the polyamide resin composition is significantly reduced. The preferred CEG amount / AEG amount is 3
Above, especially 5 or more. The effect of the CEG amount / AEG amount on the oxygen absorbency of the polyamide resin composition is unknown. However, an increase in the amount of CEG improves the oxygen absorbability, and conversely, an increase in the amount of AEG decreases the oxygen absorbability. It is considered that the negative effect is reduced.

Transition Metal Compound In the present invention, the polyamide resin composition contains a transition metal compound. The transition metal compound is necessary as a catalyst to promote the oxygen oxidation reaction. In the present invention, the amount of the transition metal in the transition metal compound is 10 to 100,000 ppm in the polyamide resin composition. When the amount of the transition metal is less than 10 ppm, the effect on the oxygen absorption of the polyamide resin composition is small.
If it exceeds 00 ppm, during the preparation of the polyamide resin composition, thermal degradation of the polyamide is promoted, and the quality and appearance of the molded product are impaired or adversely affected. The preferred amount of the transition metal is 50 to 50,000 p in the polyamide resin composition.
pm, especially 80 to 10000 ppm. It is considered that the effect of the transition metal on the oxygen absorbency is to activate the oxygen molecules by oxidizing and reducing the transition metal to promote the oxygen absorbability.

As the transition metal of the transition metal compound that can be used in the present invention, transition metals up to atomic number 29 in the periodic table are preferred in terms of handling and price, among which cobalt, iron and manganese are preferred, and cobalt is particularly preferred. preferable. Examples of the transition metal compound include an aliphatic carboxylate such as acetic acid, propionic acid, stearic acid, adipic acid, sebacic acid, and dimer acid; an aromatic carboxylate such as benzoic acid and hydroxybenzoic acid; phosphoric acid Representative examples include salts; acetylacetonate complexes; phthalocyanine complexes and the like. In addition, any other compounds can be used as long as the transition metal compound is soluble in the polyamide. Among the above, an aliphatic carboxylate such as acetic acid, propionic acid, and stearic acid of a transition metal, and an acetylacetonate complex are preferable. Specifically, cobalt acetate and its hydrate, cobalt stearate, and lauric acid are preferable. Cobalt and cobalt octoate are exemplified.

Alkali Metal Compound The polyamide resin composition of the present invention preferably contains an alkali metal compound. Generally, at the time of producing a polyamide resin containing m-xylylenediamine as a component, an alkali metal compound is used as a stabilizer for the purpose of suppressing thermal decomposition and thermal oxidative decomposition. Examples of the alkali metal M of the alkali metal compound include Li, Na, and K.
Among them, Na is preferable. As the alkali metal compound,
It is a compound containing an alkali metal, for example, an alkali metal salt of hypophosphorous acid or phosphorous acid (potassium salt, sodium salt, lithium salt and the like) and a hydrate thereof, a hydroxide of the alkali metal (for example, water Sodium oxide, potassium hydroxide, lithium hydroxide, etc.), sodium acetate, sodium acetate trihydrate, potassium acetate, lithium acetate dihydrate, etc., among which sodium hypophosphite and its hydration , Sodium hydroxide, potassium hydroxide and the like are preferred.

In the present invention, the amount of the alkali metal M in the alkali metal compound may be 10 or less in the polyamide resin composition.
0 ppm or less, more preferably 8 ppm or less.
0 ppm or less, particularly preferably 70 ppm or less.

The production of a polyamide resin containing an MXD unit as a constitutional unit can be carried out by a conventionally known method. For example, as equipment that can be employed for dehydration condensation of MXD and adipate, any of a batch type and a continuous type can be used.

CAE content and AE in polyamide resin composition
The following methods are available for adjusting the amount of G.

(1) Production of polyamide resin This is a method in which the molar balance of the dicarboxylic acid component and the diamine component is shifted in advance to either one during the production of the polyamide resin. In this method, when the dicarboxylic acid component is larger than the diamine component, the CEG amount increases. Conversely, if the diamine component is excessive, the amount of AEG increases. However, in view of the spirit of the present invention, it is desirable to increase the amount of CEG by increasing the amount of the dicarboxylic acid component relative to the diamine component.

According to this method, when producing a polyamide resin, C
Although there is an advantage that the EG amount and the AEG amount can be adjusted,
On the other hand, the polycondensation reaction may be delayed due to the loss of the molar balance between the dicarboxylic acid component and the diamine component, which may have disadvantages such as a decrease in productivity and a decrease in quality due to thermal deterioration. In order to avoid this drawback, a terminal blocking agent such as an acid anhydride is added at the end of the polycondensation reaction, and the CEG amount / A
Although a method of changing the amount of EG can be considered, since the reaction is carried out in a high-viscosity state, there is a problem in terms of the uniformity of the reaction, which is not very desirable.

(2) Modification of Terminal Group in Polyamide Resin There are two types of adjustment methods by modification of CEG or AEG. In accordance with the gist of the present invention, adjustment by modification of AEG is desirable, and this will be described.

AEG Regulator As the AEG regulator usable in the present invention, any compound having reactivity with an amino group can be used. Examples include acid anhydrides, aliphatic or aromatic carboxylic acids, and epoxy compounds. In particular, the use of an acid anhydride is preferred because of its good reactivity with an amino group and the formation of CEG by the reaction. Acid anhydrides that can be used in the present invention include, for example, acetic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Succinic acid, hexahydrophthalic anhydride, trimellitic anhydride, and phthalic anhydride are preferred.

The amount of the acid anhydride used may theoretically be equivalent to the amount of AEG in the polyamide resin.
It is arbitrarily selected according to the EG amount, the AEG amount, and the CEG amount / AEG amount. However, the use of a large excess is not preferable because the acid anhydride remains in an unreacted state and is not only harmful to the polyamide resin composition but also increases the cost. Generally, it depends on the volatility and reactivity of the acid anhydride, but usually 0.5 to 4 equivalents, preferably 0.6 to 3 equivalents, particularly preferably, based on the amount of AEG present in the polyamide resin. 0.7 to 2.5 equivalents.

AEG Modification Method As an AEG modification method using an acid anhydride, there is the following method.

I) There is a method of adding an acid anhydride to the reaction vessel after the polyamide polymerization. Since this process is a reaction having a high melt viscosity, it is a heterogeneous reaction, which is not desirable.

Ii) A polyamide resin which is pre-coated with an acid anhydride on a molding machine provided with a single-screw or twin-screw extruder,
Alternatively, a method in which a polyamide resin impregnated with a solution of an acid anhydride and an acid anhydride in a solvent inert to the polyamide is impregnated and melted and kneaded is used. Further, when the polyamide resin is supplied to the molding machine or when the polyamide resin is melted in the molding machine, the acid anhydride may be supplied in a fixed amount to be melted and kneaded. Further, the reaction between the acid anhydride and AEG can be carried out simply by using a single-screw or twin-screw extruder.
As a method for supplying the acid anhydride, the method using a molding machine described above is used in exactly the same manner.

Iii) In the continuous polymerization process of the polyamide resin, the reaction between the acid anhydride and AEG is possible. In this case, the supply of the acid anhydride is desirably performed in the final process of the continuous polymerization step, generally a single-screw or twin-screw extruder, but is preferably performed after the degree of polymerization of the polyamide reaches a desired value in this extruder step. . The extruder used in the final process is preferably equipped with a reduced pressure vent. By providing a reduced pressure vent, there is an advantage that not only the rate of polycondensation can be controlled by adjusting the degree of vacuum but also the unreacted acid anhydride can be removed.

As a method for introducing the transition metal compound into the polyamide resin, there are the following methods.

(1) Polyamide Resin Polymerization Step A transition metal compound can be introduced into the polyamide resin polymerization step regardless of the process of the polyamide resin production method, whether it is a batch type or a continuous type. According to this method, there is an advantage that the transition metal compound can be uniformly dispersed and a step of separately introducing the transition metal compound into the polyamide resin becomes unnecessary. However, since the contact time of the transition metal compound and the melt of the polyamide resin at a high temperature becomes longer, the polyamide resin is decomposed, deteriorated, or the catalytic activity of the transition metal is reduced. Absent.

(2) Melting / kneading step A molding machine provided with a single-screw or twin-screw extruder is coated with a polyamide resin or a transition metal compound and a solvent inert to the polyamide. And a method in which a polyamide resin impregnated with a solution in which is dissolved is supplied and melted and kneaded. Further, when the polyamide resin is supplied to the molding machine or when the polyamide resin is melted in the molding machine, the transition metal compound may be supplied in a fixed amount and melted and kneaded.

(3) Continuous process of polymerization and introduction of transition metal i) Polymerization step of polyamide resin + extruder process This is a continuous polymerization step and melting and kneading. This is a method of introducing a transition metal compound by attaching a single-screw or twin-screw extruder. In other words, this is a method in which the molten polyamide resin obtained in the batch or continuous polymerization step is directly supplied to a single-screw or twin-screw extruder, and the transition metal compound is separately supplied to the extruder in a constant amount. According to this method, it is not necessary to take out the polyamide resin after the polymerization once in the form of chips, pellets or other shapes, so that the cost is reduced. In addition, when the transition metal compound is introduced into the polyamide resin, a step of remelting the resin once chipped or pelletized is not required, so that a polyamide resin composition with less thermal deterioration can be obtained.

Ii) Continuous polymerization step of polyamide resin This is a continuous polymerization process comprising a raw material preparation can, a pipe reactor, an evaporator, and a finisher. Finisher is intended for polycondensation and melting / kneading,
Single-screw extruders, twin-screw extruders, self-cleaning reactors and the like are preferred. Poly-m-xylylene adipamide will be described as a polymerization example. m-xylylenediamine (MXD) and adipic acid, and sodium hydroxide;
Sodium hypophosphite and water are charged into a raw material mixing can, and MXD-
An aqueous solution of adipate is prepared, and the aqueous solution is supplied to a pipe reactor and reacted under heating and pressure to obtain a low molecular weight product. The low molecular weight substance is evaporated into water in an evaporator to form an initial polymer, and then subjected to polycondensation under reduced pressure in a twin-screw extruder, and the resulting poly-m-xylylene adipamide is stranded in ice. Cool and cut into chips with a cutter. Next, a Co compound or an acid anhydride is supplied to a twin-screw extruder and melted and kneaded to obtain a polyamide resin composition having an oxygen absorbing ability. In this continuous polymerization method, the time required from raw material preparation to polymer removal is short, not only productivity is higher than other polymerization methods, but also the time affected by heat is short, so there is little deterioration, quality There is an advantage that an excellent polymer can be obtained.

The relative viscosity of the polyamide resin composition of the present invention is preferably in the range of 0.5 to 4.0. A polyamide resin composition having a relative viscosity of more than 4.0 requires a long time for polymerization, so that the polyamide resin is deteriorated and undesirably colored. Conversely, in a polyamide resin composition having a relative viscosity of less than 0.5,
The molecular weight of the polyamide resin is too small, resulting in poor mechanical properties.

In the production of the polyamide resin composition of the present invention, the transition metal compound is
The alkali metal compound used as the stabilizer is used so that the amount of the transition metal is 10 to 100,000 ppm, and the alkali metal is preferably used in the polyamide resin composition so as to be 100 ppm or less.

The polyamide resin of the present invention may contain various additives for the purpose of improving mechanical properties, chemical stability, color tone and the like. For example, glass, talc,
Examples include fillers such as silica, pigments such as titanium oxide and carbon black, and stabilizers such as a heat-resistant oxidizing agent and a UV-absorbing agent. In using these additives, it is important to select additives that do not harm the oxygen absorption.

The thus obtained polyamide resin composition has high oxygen absorption. Specifically, the amount of oxygen absorbed per 1 g of the polyamide resin composition is 0.1 mmo.
1 or more, preferably 0.12 mmol or more, more preferably 0.13 mmol or more. Therefore, it is possible to prevent a change in the quality of oxygen-sensitive substances such as beverages and foods due to oxygen, and therefore, it is possible to store for a longer period of time.

[0040]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the examples, “parts” means “parts by weight”. The properties and physical properties shown in the following examples and comparative examples were measured by the following test methods.

(1) Measurement of relative viscosity (RV): 0.25 g of polyamide resin or polyamide resin composition
Was dissolved in 25 ml of 96.3% sulfuric acid.
1 was placed in an Ostwald viscosity tube, measured at 20 ° C., and calculated by the following equation. RV = t / t ₀ t: sample solution dropping time of t _0: falling time of the solvent

(2) Measurement of Amino Terminal Group (AEG) Amount 0.6 g of a polyamide resin or a polyamide resin composition was dissolved in 50 ml of phenol / ethanol (volume ratio: 4/1), and then water / ethanol (volume ratio: 3). / 2) 20m
1 was added and a drop of the indicator methyl orange was added. It was titrated with an ethanolic hydrochloric acid aqueous solution (prepared to 500 ml by adding distilled water to 100 ml of 1 / 10N HCl and 50 ml of ethanol), and calculated by the following formula. The valence of the transition metal was subtracted as a blank. AEG (meq / kg) = ｛[(AB) × N × f]
/ (W × 1000)｝ × 10 ⁶ -CA A: titration (ml) B: blank titration of solvent (ml) N: concentration of ethanolic HCl (mol / l) f: factor of ethanolic HCl w: Weight (g) of polyamide resin or polyamide resin composition (sample) C: valence of transition metal (meq / kg)

(3) Measurement of Carboxyl End Group (CEG) Amount 10 ml of benzyl alcohol was added to 0.2 g of the polyamide resin or the polyamide resin composition and dissolved at 180 ± 5 ° C. for 5 minutes. The solution was cooled in water for 15 seconds, titrated with ethanolic potassium hydroxide solution (prepared to 1000 ml by adding ethanol to 80 ml of 0.5 N KOH) using phenolphthalein as an indicator, and calculated by the following equation. CEG (meq / kg) = ｛[(AB) × N × f]
/ (W × 1000)｝ × 10 ⁶ A: titer (ml) B: blank titer for dissolution (ml) N: concentration of ethanolic potassium hydroxide (mol / l) f: factor of ethanolic potassium hydroxide w: weight (g) of polyamide resin or polyamide resin composition (sample)

(4) Measurement of oxygen absorption amount 3 g of a polyamide resin composition pulverized to about 10 μm and water 3
ml was placed in a 120 ml vial bottle, sealed with silicone packing, and allowed to stand in a thermostat at 25 ° C. Two days later, a gas tight syringe was used to collect 0.5 ml of the internal gas, and a gas chromatograph GC-8A manufactured by Shimadzu Corporation was used.
Was used to measure the oxygen concentration, and the oxygen absorption amount was evaluated from the oxygen concentration at this time and the oxygen concentration before the test. The oxygen concentration was determined from the area ratio to nitrogen. The measurement conditions of the gas chromatograph are as follows. Analysis column: molecular sieves 13 × S, φ2.6
mm × 3m Temperature: Injector and detector 60 ° C., column 30 ° C. Detector: TCD Detector current: 100 mA Carrier gas: Helium 40 ml / min The vial bottle from which the internal gas was collected with a gas tight syringe was immediately opened. This operation was repeated 5 times every 2 days (total 10 days). The oxygen absorption capacity in Tables 3 to 6 is represented by the cumulative amount of oxygen absorbed 5 times (total of 10 days) performed every two days in terms of mmol per 1 g of polyamide. It is desirable that the amount of oxygen absorbed by the polyamide resin composition is large from the viewpoint of the invention. In the present invention,
Oxygen absorption is 0.1 mmol or more, preferably 0.12
mmol or more, more preferably 0.13 mmol or more.

<Production Method of Polyamide> 1360 parts of m-xylylenediamine, 1460 parts of adipic acid, 1.74 parts of sodium hypophosphite monohydrate and 1.09 parts of sodium hydroxide as a stabilizer, and 2460 parts of water were used. Charge the reactor into a pressurized reactor, and raise the jacket temperature to 27
The temperature was raised to 5 ° C. During this period, the reaction temperature was 190 ° C., the internal pressure of the kettle was regulated at 1.0 MPa, and the reaction temperature was 240 ° C. together with the distillation of the condensed water. Pressure release was started 200 minutes after the start of temperature rise, and normal pressure was reached in 50 minutes. During this period, the reaction temperature rose to 260 ° C., and the reaction was continued for another 50 minutes under the same conditions. Then, the polyamide was discharged into water in a strand form and formed into chips with a cutter. This is designated as polyamide A. Polymerization was carried out in the same manner as for polyamide A, except that the amount of the stabilizer was changed, to obtain polyamides B, C, D and E. Table 1 shows the properties of the polyamides A to E.

[0046]

[Table 1]

<Production method of polyamide> 1360 parts of m-xylylenediamine, 2020 parts of sebacic acid, 2.07 parts of sodium hypophosphite monohydrate and 1.32 parts of sodium hydroxide as stabilizers, and 3380 parts of water were used. It was charged into a pressure reactor and polymerized in the same manner as polyamide A to obtain polyamide F. Polymerization was carried out in the same manner as for polyamide F, except that no stabilizer was used, to give polyamide G. Table 2 shows the properties of polyamides F and G.

<Production method of polyamide> 1360 parts of m-xylylenediamine, 730 parts of adipic acid, 830 parts of isophthalic acid, 1.06 parts of sodium hypophosphite monohydrate and 0.4 parts of sodium hydroxide as stabilizers, More water 33
80 parts were charged into a pressure reactor, and polymerized in the same manner as polyamide A to obtain polyamide H. Table 2 shows the properties of polyamide H.

<Production method of polyamide> 476 parts of m-xylylenediamine, 754 parts of hexamethylenediamine, 1460 parts of adipic acid, and 3000 parts of water were charged into a pressure-type reaction vessel, and polymerized in the same manner as polyamide A to obtain polyamide I. I got The diamine component in polyamide I is
m-Xylylenediamine was 35 mol%. Table 2 shows the properties of Polyamide I.

<Production Method of Polyamide> 816 parts of m-xylylenediamine, 464 parts of hexamethylenediamine, 1460 parts of adipic acid, and 3000 parts of water were charged into a pressure reactor, and polymerized in the same manner as polyamide A to obtain polyamide J. I got The diamine component in polyamide J is
m-xylylenediamine was 60 mol%. Table 2 shows the properties of polyamide J.

<Production Method of Polyamide> 680 parts of m-xylylenediamine, 565 parts of ε-caprolactam, 730 parts of adipic acid and 3,000 parts of water were charged into a pressure reactor, and polymerized in the same manner as polyamide A to obtain polyamide K. I got The diamine component in the polyamide K was 50 mol% of m-xylylenediamine. Polyamide K
Are shown in Table 2.

[0052]

[Table 2]

Examples 1 to 4 and Comparative Examples 1 to 4 Cobalt acetate tetrahydrate was added to polyamide A so that the amount of Co in the polyamide resin composition was as shown in Table 3 as a transition metal compound. Then, hexahydrophthalic anhydride was added as an AEG regulator so that the amount in the polyamide resin composition became the amount shown in Table 3, and the mixture was melt-kneaded at 265 ° C. with a twin-screw extruder. The following polyamide resin composition was obtained. It can be seen that by adjusting the AEG, the CEG amount and the CEG amount / AEG amount are increased and the AEG amount is decreased, whereby the oxygen absorbing ability of the obtained polyamide resin composition is significantly increased. Further, the amount of the metal of the transition metal compound is 10% in the polyamide resin composition.
In Comparative Example 4 exceeding 0000 ppm, it can be seen that the molecular weight of the polyamide resin composition was significantly reduced due to decomposition.

[0054]

[Table 3]

Examples 5 to 7 Cobalt acetate tetrahydrate was added to polyamide A as a transition metal compound so that the amount of Co in the polyamide resin composition became 500 ppm, and succinic anhydride (AEG regulator) was used. Example 5), except that trimellitic anhydride (Example 6) or phthalic anhydride (Example 7) was added such that the amounts in the polyamide resin composition were as shown in Table 4, respectively. In the same manner as in Example 1, a polyamide resin composition shown in Table 4 was obtained.

[0056]

[Table 4]

Examples 8 to 9 and Comparative Examples 5 to 6 Polyamides B, C, D and E each had a transition metal compound having a Co content of 500 p in the polyamide resin composition.
Except that cobalt acetate tetrahydrate was added so as to obtain pm, a polyamide resin composition shown in Table 5 was obtained in the same manner as in Example 1. From Comparative Examples 5 and 6 in Table 5,
It can be seen that when the AEG amount is large and the CEG amount / AEG amount is small, the oxygen absorbing ability is significantly reduced.

[0058]

[Table 5]

Examples 10 to 13 and Comparative Example 7 Cobalt acetate tetrahydrate (Example 13) or stearic acid was added to polyamide B so that the transition metal compound contained 500 ppm of Co in the polyamide resin composition. Cobalt (Examples 10 to 12, Comparative Example 7) was added, and hexahydrophthalic anhydride was added as an AEG regulator so that the amounts in the polyamide resin composition were as shown in Table 6, respectively. As in Example 1,
The polyamide resin composition shown in Table 6 was obtained. From Comparative Example 7 in Table 6, it can be seen that when the AEG amount is large and the CEG amount / AEG amount is small, the oxygen absorption capacity is significantly reduced.

[0060]

[Table 6]

Examples 14 to 19 and Comparative Examples 8 to 11 Polyamides F, G, H, I, J and K were respectively added as transition metal compounds so that the amount of Co in the polyamide resin composition became 500 ppm. Cobalt acetate tetrahydrate (Example 14, Comparative Example 8) or cobalt stearate (Examples 15-19, Comparative Examples 9-11) was added, and A was added.
Except that hexahydrophthalic anhydride was added as an EG adjuster such that the amount in the polyamide resin composition was as shown in Table 7, respectively, the polyamide resin composition shown in Table 7 was prepared in the same manner as in Example 1. Obtained. In Comparative Example 11, the diamine component in the polyamide I used was:
The composition containing the m-xylylenediamine component in an amount of 35 mol% and the polyamide contains m-xylylenediamine in the diamine component even if the CEG amount, the AEG amount and the CEG amount / AEG amount are within the range of the present invention. 40% by mole of diamine component
It can be seen that the oxygen absorption capacity is remarkably reduced because the value is less than the above.

[0062]

[Table 7]

[0063]

According to the polyamide resin composition of the present invention, the oxygen absorbing ability is further improved, and the deterioration of the quality of oxygen-sensitive substances such as beverages and foods due to oxygen can be prevented. . Therefore, the polyamide resin composition of the present invention can be used as a film or sheet having deoxidation properties, and can be used for all or a part of materials such as a container body, a lid, and a packaging bag. Furthermore, when present in a container or bag in the form of pellets, powder, or plate, it can be used as a deoxidizer.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Makoto Ito 10-24, Toyo-cho, Tsuruga-shi, Fukui F-term in Toyobo Co., Ltd. Polymer Development Center (reference) 4J002 CL031 EG046 GG00

Claims (1)

[Claims] 1. A polyamide resin composition comprising a polyamide resin and a transition metal compound, wherein: a) the diamine component of the polyamide resin contains at least 40 mol% of m-xylylenediamine; Carboxyl end groups (CE
G) The amount is 50 meq / kg in the polyamide resin composition.
As described above, the amino terminal group (AEG) in the polyamide resin
The amount is 30 meq / kg or less in the polyamide resin composition, and the carboxyl terminal group (CEG) amount / amino terminal group (AEG) amount in the polyamide resin is 2 or more; and c) transition of the transition metal compound. A polyamide resin composition, wherein the amount of the metal is 10 to 100,000 ppm in the polyamide resin composition.