JPH09316191A - Production of polyamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a process for producing a polyamide which has m- xylylenediamine units as essential units, does not gel nor yellow, and has a homogeneous quality and a good film-forming properties by using specific components. SOLUTION: An oligomer having a number average mol.wt. of 800 or higher and comprising 25-50mol% diamine units comprising 20-100mol% m- xylylenediamine units and 0-80mol% units derived from an aliph. and/or alicyclic diamine having a 4-18C alkylene group, 25-50mol% 6-18C linear aliph. dicarboxylic acid units, and 0-50mol% 4-12C aliph. ω-aminocarboxylic acid units is produced by the prepolymn. at 240 deg.C or lower. The oligomer is subjected to melt polymn. at a temp. at least 10 deg.C higher than the m.p. of the polymer obtd. from the oligomer but not higher than 280 deg.C and/or is subjected to solid phase polymn. at a temp. not lower than the glass transition point of the polymer but at least 10 deg.C lower than the m.p.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyamide having specific components and compositions. More specifically, it relates to a method for producing a polyamide containing a metaxylylenediamine component unit as an essential component and suitable as a gas barrier packaging material.

[0002]

2. Description of the Related Art In the production of polyamides using metaxylylenediamine as a raw material, it is important not to cause gelation during polymerization in order to produce homogeneous and good polyamides. For that purpose, it is required to establish a method for producing a polyamide in which generation of secondary amine caused by metaxylylenediamine dimerization deammonification reaction which is considered to be a main factor of gelation is suppressed as much as possible.

Conventionally, as a method for producing a homogeneous and good polyamide using metaxylylenediamine as a raw material, a method of strictly controlling the polymerization temperature, the polymerization time, the steam pressure and the like to suppress the decomposition of amino groups as much as possible (specially Kosho 35-7596
(See Japanese Patent Publication No. 40-1457), a method of lowering the melting point of the obtained polyamide by copolymerization with ε-caprolactam, and producing it under mild temperature conditions (see Japanese Patent Publication No. 40-1457). In addition, Japanese Patent Publication 47-
In Japanese Patent No. 51480, in order to obtain a polyamide free from coloring or gel in the production of a polyamide using metaparaxylxylylenediamine containing 30 mol% or less of metaxylylenediamine or paraxylylenediamine as a raw material,
The polycondensation reaction rate is controlled by applying a reaction involving a reverse reaction with water present in the polycondensation system so that the relative viscosity of the resulting polyamide is within a specific range, and the final step is pressurized or atmospheric pressure. Have been reported to complete the polycondensation.

[0004]

However, in the method described in Japanese Patent Publication No. 35-7596, it is necessary to strictly control the polymerization temperature, the polymerization time, and the steam pressure in the polymerization system. When the manufacturing scale changes, the manufacturing conditions must be changed each time, which is a very inconvenient method for industrial use. The method described in Japanese Examined Patent Publication No. 40-1457 aims to suppress the production of ammonia by producing a polyamide under mild conditions by copolymerization with ε-caprolactam in an amount whose main point is a specific range. However, it does not mention the production conditions of the polyamide prepared from metaxylylenediamine. Furthermore, the method described in JP-B-47-51480 is
Although it is a method of producing a good polymer without gel by adjusting only the water vapor pressure in the final step of the polymerization process, according to the findings of the present inventors detailed below, to suppress gelation. It is very important to control the temperature during the initial polymerization and the molecular weight of the polyamide formed at that time, and it is considered that gelation of the obtained polyamide can be suppressed by appropriately adjusting only the steam pressure in the final step of the method. hard.

Therefore, an object of the present invention is to use, in addition to metaxylylenediamine, which is an essential component, an aliphatic and / or alicyclic diamine having an alkylene group having 4 to 18 carbon atoms as a diamine component raw material, A linear aliphatic dicarboxylic acid having 6 to 18 atoms is used as a dicarboxylic acid component raw material,
Furthermore, in the method for producing a polyamide using an aliphatic ω-aminocarboxylic acid having 4 to 12 carbon atoms as a raw material,
Amino group concentration of secondary amine produced by dimerization deammonification reaction between metaxylylenediamine ([N
It is an object of the present invention to provide a method for producing a polyamide having a uniform and good film-forming property, which is free from gelation and yellowing, in which H]) is substantially suppressed to zero.

[0006]

MEANS FOR SOLVING THE PROBLEMS The present inventors have found that metaxylylenediamine as a diamine component, an aliphatic and / or alicyclic diamine having an alkylene group having 4 to 18 carbon atoms, and a dicarboxylic acid component as a dicarboxylic acid component. A linear aliphatic dicarboxylic acid having 6 to 18 carbon atoms, and
As a result of extensive studies on a method for producing a homogeneous and good polyamide free from gels and yellowing, which is made from an aliphatic ω-aminocarboxylic acid having 4 to 12 carbon atoms, first, in the initial polymerization, a diamine component unit was used. The metaxylylenediamine component unit is 20 to 100 mol% and the aliphatic and / or alicyclic diamine component unit having an alkylene group having 4 to 18 carbon atoms is 0 to 80 mol% based on the whole. The diamine component unit is 25 to 50 mol%, the linear aliphatic dicarboxylic acid component unit having 6 to 18 carbon atoms as the dicarboxylic acid component unit is 25 to 50 mol%,
And 0 to 50 mol% of the aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms (provided that the diamine component unit and the dicarboxylic acid component unit are equimolar%, and the diamine component unit and the dicarboxylic acid unit are dicarboxylic acid units). The total number of the acid component unit and the aliphatic ω-aminocarboxylic acid component unit is 100 mol%), an oligomer having a number average molecular weight of 800 or more is produced at a temperature of 240 ° C. or less, and then the oligomer is obtained. From the melting point of the polymer obtained, 1
Melt polymerization is performed at a temperature in the range of 0 ° C. or higher and 280 ° C. or lower, or solid phase polymerization is performed in the range of a glass transition temperature or higher of the resulting polymer and 10 ° C. or lower lower than the melting point. 10 from the melting point of the polymer
After melt-polymerization at a temperature in the range of ℃ higher than 280 ℃, the glass transition temperature of the polymer is higher than 1
The inventors have found that a solid and good polyamide free from gelation and yellowing can be obtained by solid phase polymerization at a temperature lower than 0 ° C. or lower, and have completed the present invention.

That is, the first invention according to claim 1 is such that the metaxylylenediamine component unit is 20 to 100 mol% and the number of carbon atoms is 4 to 18 with respect to the entire (A) diamine component unit. 25 to 50 mol% of a diamine component unit consisting of 0 to 80 mol% of an aliphatic and / or alicyclic diamine component unit having an alkylene group, and (B) a dicarboxylic acid component unit having 6 to 18 carbon atoms. 25-50 mol% of linear aliphatic dicarboxylic acid component unit,
And (C) the aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms is 0 to 50 mol% (provided that the component unit (A) and the component unit (B) are equimolar%, and ,
An oligomer having a number average molecular weight of 800 or more composed of component units (A), (B) and (C) is 100 mol%) is prepared by prepolymerization at a temperature of 240 ° C. or less, This can be achieved by providing a method for producing a polyamide, characterized in that the oligomer is used for melt polymerization at a temperature in the range of 10 ° C. higher than the melting point of the obtained polymer to 280 ° C.

In a second aspect of the present invention, the metaxylylenediamine component unit is 20 to 100 mol% and the number of carbon atoms is 4 with respect to the total amount of the (A) diamine component unit.
25 to 50 mol% of the diamine component unit consisting of 0 to 80 mol% of the aliphatic and / or alicyclic diamine component unit having 18 to 18 alkylene groups, and (B) having 6 carbon atoms as the dicarboxylic acid component unit. 25 to 50 mol% of the linear aliphatic dicarboxylic acid component unit of -18, and
(C) 0 to 50 mol% of the aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms (provided that the component unit (A) and the component unit (B) are equimolar%, and The sum of units (A), (B) and (C) is 100 mol%
An oligomer having a number average molecular weight of 800 or more, which is produced by prepolymerization at a temperature of 240 ° C. or less, and then using this oligomer, the glass transition temperature of the obtained polymer or more and its melting point. This can be achieved by providing a method for producing a polyamide, which comprises performing solid phase polymerization at a temperature in the range of 10 ° C. lower or lower.

The third invention according to claim 3 is
(A) 20 to 100 mol% of metaxylylenediamine component units with respect to the entire diamine component units, and aliphatic and / or alkylene groups having 4 to 18 carbon atoms.
Alternatively, 25 to 50 mol% of a diamine component unit consisting of 0 to 80 mol% of an alicyclic diamine component unit, and (B) a linear aliphatic dicarboxylic acid component having 6 to 18 carbon atoms as a dicarboxylic acid component unit The unit is 25 to 50 mol%, and (C) the aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms is 0 to 50 mol% (however, the component unit (A) and the component unit (B)). Are equimolar%, and the total of the component units (A), (B) and (C) is 100 mol%
An oligomer having a number average molecular weight of 800 or more, which is formed by prepolymerization at a temperature of 240 ° C. or lower, and then using this oligomer, a temperature of 10 ° C. or higher higher than the melting point of the resulting polymer, A method for producing a polyamide, comprising melt-polymerizing at a temperature in the range of 280 ° C or lower, and then performing solid-phase polymerization at a temperature in the range of the glass transition temperature of the polymer or higher and 10 ° C lower than the melting point of the polymer. Can be achieved by doing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below in detail. The raw materials for the components constituting the polyamide obtained by the method of the present invention include, in addition to metaxylylenediamine, diamines and dicarboxylic acids specifically shown below or salts obtained therefrom, ω-aminocarboxylic acids, or three-membered members. A lactam having a ring or more is preferably used. Metaxylylenediamine as the diamine component raw material (A) is an essential component. Further, as the aliphatic and / or alicyclic diamine having an alkylene group having 4 to 18 carbon atoms as the diamine component raw material (A),
For example, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminopeptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane. , 1,11-diaminoundecane, 1,12-diaminododecane, 1,1
3-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminopeptadecane, 1,18-diaminooctadecane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane,
1,3-bis (aminomethyl) cyclohexane, 1,4
-Bis (aminomethyl) cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis (4-aminocyclohexyl) methane and bis (4
-Aminocyclohexyl) propane and the like. Further, as the linear aliphatic dicarboxylic acid having 6 to 18 carbon atoms as the dicarboxylic acid component raw material (B), for example, butanedioic acid, pentanedionic acid, hexanedioic acid, heptanedioic acid, octanedionic acid, Nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid and the like can be mentioned.

On the other hand, an aliphatic ω- having 4 to 12 carbon atoms
As the component (C) constituting the aminocarboxylic acid unit,
For example, ω-aminocarboxylic acids such as ε-aminocaproic acid, ω-aminoheptanoic acid, ω-aminononanoic acid, ω-aminoundecanoic acid and ω-aminododecanoic acid,
Cyclic amide compounds such as ε-caprolactam, ω-enanthlactam, ω-undecanelactam, ω-dodecalactam, α-pyrrolidone, δ-methylpyrrolidone and α-piperidone (lactams having three or more membered rings) and the like can be mentioned. .

In the initial polymerization (pre-polymerization step) of the present invention, for example, the above-mentioned powdery raw materials (diamine and dicarboxylic acid or salts obtained from them, ω-aminocarboxylic acid, or lactam having three or more membered rings) Are blended in the form of an aqueous solution of a salt and / or a monomer, or the like, and these raw materials premixed in a predetermined ratio or these raw materials and a predetermined amount of water are charged into a polymerization tank, An oligomer can be obtained by polymerizing under a predetermined condition while stirring.

In the method of the present invention, in each of the above-mentioned raw materials, in the oligomer obtained, the metaxylylenediamine component unit is 20 to 1 with respect to the whole (A) diamine component unit
25 mol of the diamine component unit consisting of 0 to 80 mol% of the aliphatic and / or alicyclic diamine component unit having an alkylene group having 4 to 18 carbon atoms.
˜50 mol%, (B) 25 to 50 mol% of a linear aliphatic dicarboxylic acid component unit having 6 to 18 carbon atoms as a dicarboxylic acid component unit, and (C) having 4 carbon atoms.
~ 12 aliphatic ω-aminocarboxylic acid component units 0-5
0 mol% (however, the component unit (A) and the component unit (B) are equal mol%, and the total of the component units (A), (B) and (C) is 100 mol%). It must be mixed in such a ratio.

The polymerization temperature in the pre-polymerization step under pressure of the present invention should be 240 ° C. or lower, preferably 150 ° C. or higher and 240 ° C. or lower. Polymerization temperature is 240
When the temperature is higher than 0 ° C, the side reaction causes an increase in the amino group concentration ([NH]) of the secondary amine in the oligomer, yellowing of the oligomer, and gelation during post-polymerization. Further, if the polymerization temperature is lower than 150 ° C., the polymerization time becomes extremely long and inefficient, so that it cannot be said to be in a desirable state from the viewpoint of productivity. In the method of the present invention, the pressure in the polymerization system in the prepolymerization step is the pressure in the prepolymerization apparatus at that time, and is mainly the steam pressure at the polymerization equilibrium shown by the mixture of the oligomer and water. Therefore, the pressure in the polymerization system, that is, the water vapor pressure can be appropriately adjusted to a pressure equal to or lower than the saturated water vapor pressure depending on the above-mentioned polymerization temperature and the amount of water described later, and there is no particular limitation, but 3 kgf / cm ² G ( However, G represents a gauge pressure, and the same shall apply hereinafter) or higher and a saturated steam pressure or lower, preferably 4 kgf / cm ² G or higher and a saturated steam pressure or lower. The pressure in the polymerization system is 3 kgf / cm
^When it is lower than ² G, the polymerization system may be non-uniformly polymerized in a solid state, which is not preferable. And the pressure of the polymerization system is 3
kgf / cm ² G or more, if a range of less than 4 kgf / cm ² G, a tendency that undesirable phenomenon described above occurs is observed. The pressure can be adjusted by, for example, a valve provided in a steam discharge line directly connected to the prepolymerization apparatus.

In the method of the present invention, when a predetermined amount of the powdery raw material and a predetermined amount of water are charged in the prepolymerization apparatus during the prepolymerization, the water supplied to the prepolymerization apparatus is not particularly limited. However, pure water such as ion-exchanged water or distilled water is preferable. The presence of water in the prepolymerization apparatus is based on the water supplied to the prepolymerization apparatus and the water produced by the polycondensation reaction of the raw materials supplied to the prepolymerization apparatus. It is possible to maintain the above pressure by means of the water vapor pressure in the prepolymerization device, and to determine the molecular weight of the obtained oligomer.

The amount of water present in the prepolymerization apparatus is determined by the type, shape and size of the prepolymerization apparatus, the amount of the raw material or the raw material and water charged into the prepolymerization apparatus, and the temperature of the prepolymerization apparatus. It is determined depending on the pressure conditions and the like and cannot be generally stated, but based on the charging standard of the raw material to the prepolymerization apparatus, 100 parts by weight or less, preferably 50 parts by weight or less, per 100 parts by weight of the total amount of the raw materials. Is desirable. The amount of water is 1 per 100 parts by weight of the total amount of the raw materials
When it is more than 100 parts by weight, the polycondensation reaction of the above-mentioned raw material, diamine and dicarboxylic acid, or a salt obtained from these, or ω-aminocarboxylic acid, or the polycondensation reaction after ring-opening of the above-mentioned raw material lactam is sufficient. It does not proceed, and the degree of polymerization of the obtained oligomer becomes small, and therefore the degree of polymerization does not increase in the post-polymerization step, which is not preferable. When the amount of water is more than 50 parts by weight and less than 100 parts by weight per 100 parts by weight of the total amount of the raw materials, this unfavorable phenomenon may occur.

In the method of the present invention, the molecular weight of the oligomer is determined by determining the terminal group concentration (amino group concentration ([NH ₂ ])) and carboxyl group concentration ([COO
H])) has a number average molecular weight (hereinafter abbreviated as “Mn”) of 800 or more, preferably 800 to 3000.
It is desirable that For that purpose, pre-polymerization is performed under the above conditions (polymerization temperature, polymerization pressure, water supply ratio with respect to the charged amount of the raw material, etc.), and subsequently, at a temperature of 240 ° C. or lower, pressure is released to a pressure of normal pressure or lower, After removing the generated condensed water, it is necessary to move to the post-polymerization step. If the Mn of the oligomer is less than 800, the concentration of the terminal group is unbalanced by distilling the diamine component out of the system during the post-polymerization, the molecular weight does not increase, and deammonification dimerization between meta-xylylenediamines occurs. A secondary reaction or the like occurs with the increase of the secondary amine concentration ([NH]).
That is, when the post-polymerization is carried out first under melting, the post-polymerization under normal pressure and / or under reduced pressure, which is performed at a higher temperature than the pre-polymerization under the above-mentioned pressure, is used as described above.
It is substantially the same as polymerizing the above-mentioned raw material monomer at an unfavorable temperature exceeding ℃, the side reaction becomes remarkable, the end group concentration balance is lost due to evaporation of the diamine component, etc. The resulting polyamide has an unfavorable physical property effect. On the other hand, in order to increase the Mn of the oligomer to more than 3000, it is necessary to leave it in a heated state for a long time in the polymerization under the prepolymerization conditions, which may have an unfavorable influence on the physical properties of the finally obtained polyamide. There is a nature.

When the condensation water produced as a by-product is not removed by releasing the pressure to a pressure lower than the normal pressure, the weight of the oligomer is reduced in the subsequent post-polymerization step under the normal pressure and / or the reduced pressure. It is not preferable because the condensation reaction does not proceed sufficiently and the molecular weight of the obtained polyamide is not sufficiently increased. Further, when the pressure is released below the atmospheric pressure at a temperature over 240 ° C. after the prepolymerization, a branched structure is generated by a side reaction, coloring and gelation in the postpolymerization step under the atmospheric pressure and / or the reduced pressure may occur. It is not preferable because it occurs.

In the method of the present invention, there is no particular limitation on the apparatus for carrying out prepolymerization (prepolymerization apparatus), and a batch reactor, a one-tank type or multi-tank type continuous reaction apparatus, or a tubular continuous reaction apparatus is used. Known materials such as these can be used. Among these, a batch reactor is preferably used in order to make the polymerization time of the oligomer uniform.

In the method of the present invention, the oligomer obtained as described above is polymerized into a high molecular weight in the subsequent post-polymerization step to obtain a polyamide having film moldability and characteristics characteristic of the present invention. Be done.

In the post-polymerization step under atmospheric pressure and / or reduced pressure in the method of the first aspect of the present invention, the melting point of the finally obtained polyamide is + 10 ° C. to 280 ° C., preferably the melting point + 20 ° C. to 270 ° C. The final polyamide can be obtained by melt polymerization at a temperature in the range. If the polymerization temperature during melt polymerization is lower than the melting point of the finally obtained polyamide + 10 ° C, the polymer (polyamide)
May not be completely melted, and the target polyamide may not be stably manufactured due to partial solidification during manufacture. In addition, the polymerization temperature during melt polymerization is 28
When the temperature is higher than 0 ° C., heat deterioration causes coloring of the finally obtained polyamide and deterioration of mechanical properties, which is not preferable. In order to reliably suppress the occurrence of these unfavorable phenomena, it is necessary to set the polymerization temperature during melt polymerization within the above-mentioned preferable range.

In the post-polymerization step under normal pressure and / or reduced pressure in the method of the second invention, the temperature is in the range of not less than the glass transition temperature of the polyamide finally obtained and not more than 10 ° C. lower than its melting point. The final polyamide can be obtained by solid phase polymerization at a temperature, preferably in the range of not lower than the glass transition temperature of the finally obtained polyamide and not higher than 20 ° C. lower than its melting point. When the polymerization temperature during solid phase polymerization is lower than the glass transition temperature of the finally obtained polyamide, the polymerization does not substantially proceed, and the temperature is lower than the melting point of the finally obtained polyamide within 10 ° C. If so, the polymer may be partially melted and stable solid-phase polymerization may not be possible. In addition,
In order to reliably suppress the occurrence of these unfavorable phenomena, it is necessary to set the polymerization temperature during solid phase polymerization within the above-mentioned preferable range. The solid phase polymerization in the method of the present invention is carried out under normal pressure and / or reduced pressure, and under normal pressure it is carried out under the flow of an inert gas such as nitrogen gas in order to suppress oxidative deterioration during polymerization, coloring and the like. Preferably.

In the post-polymerization step under normal pressure and / or reduced pressure in the method of the third invention, the melting point of the finally obtained polyamide is + 10 ° C. to 280 ° C., preferably the melting point + 20 ° C. to 270 ° C. After melt polymerization at a temperature in the range, the temperature is in the range of not less than the glass transition temperature of the polyamide and not more than 10 ° C. lower than the melting point thereof, preferably not less than the glass transition temperature of the polyamide and not more than 20 than the melting point thereof.
The final polyamide can be obtained by solid phase polymerization at a temperature in the range of ℃ lower than. When the polymerization temperature during melt polymerization or solid phase polymerization is out of the above range, the same as in the post-polymerization step under normal pressure and / or reduced pressure in the method of the first invention or the method of the second invention described above. Such an undesirable phenomenon may occur. When the solid-state polymerization after the melt polymerization is carried out under normal pressure, it is preferably carried out under the flow of an inert gas such as nitrogen gas as in the case of the post-polymerization step in the method of the second invention. .

Next, the pressure during the post-polymerization is, as described above, normal pressure and / or reduced pressure, and when performing melt polymerization, it is preferably 50 to 760 mmHg, particularly preferably 100 to 760 mmHg, and the solid phase. When polymerizing,
Preferably 1 to 760 mmHg, particularly preferably 10
It is 760 mmHg. When the pressure is higher than 760 mmHg during melt polymerization or solid phase polymerization, water vapor in the oligomer and by-product water resulting from the polycondensation reaction of the oligomer are actively exhausted out of the system. It is not preferable because the polycondensation reaction of the oligomer does not proceed sufficiently. Further, if the pressure is less than 50 mmHg (when performing melt polymerization) or less than 1 mmHg (when performing solid phase polymerization), not only a further accelerating effect on the polycondensation reaction of the oligomer cannot be expected, but also a decompression facility for exhausting the gas. It is not preferable because it costs a lot. The exhaust is performed by providing at least one vent port in the post-polymerization apparatus described below and opening the vent port to the atmosphere, or by using a known port such as a Nash pump, mechanical booster, or steam ejector for the vent port. It is performed by connecting to vacuum equipment and forcibly exhausting.

The polymerization time under normal pressure and / or reduced pressure should be selected so that the molecular weight is sufficiently increased and the polymer (polyamide) does not undergo thermal decomposition. Usually, when melt polymerization is carried out. It is from 0.1 to 8 hours, and from 0.5 to 20 hours when solid phase polymerization is performed. If the polymerization time is shorter than the above range, the increase in the molecular weight of the polymer is not sufficient, and if it is long, the polymer undergoes thermal deterioration, and in any case it is not possible to obtain a polyamide having the desired physical properties, which is not preferable. .

In the method of the present invention, a polyamide can be obtained under the above-mentioned conditions, but the process for producing the polyamide of the present invention is not particularly limited, and it may be a batch process or a continuous process. It may be. In the case of a batch process, the pre-polymerization step and the post-polymerization step may be carried out in one reactor, or only the pre-polymerization step is carried out in a pressure reaction vessel and the melt polymerization is carried out in the post-polymerization step (first According to the method of the invention and the method of the third invention), the melt polymerization has a short residence time, but is excellent in surface renewal, and is a kneading extruder (single-screw kneading extruder, twin-screw kneading extruder and multi-screw extruder). Type kneading extruder) and Japanese Patent Publication No. 4-
It may be carried out using a device such as a horizontal second polymerization tank (biaxial mixing stirrer) disclosed in Japanese Patent No. 32096. If solid-phase polymerization is carried out in the post-polymerization step (the method of the second invention and the method of the third invention), the solid-phase polymerization is the oligomer obtained by using the pressure reaction vessel, or As a raw material, a polymer obtained through prepolymerization under pressure using a pressure reactor and melt polymerization using the kneading extruder or biaxial mixing stirrer, a static system, a blender, a Nauter mixer, etc. It is carried out with the stirring system used. In the case of a continuous process, a known one such as a one-tank type or multi-tank type continuous reaction apparatus or a tubular continuous reaction apparatus can be used.

The polyamide for barrier film of the present invention thus obtained is a homopolyamide or copolyamide composed of the above-mentioned polyamide-forming component units, and has Mn in the range of 7,000 to 30,000. When Mn is less than 7,000, a polyamide having desired film physical properties cannot be obtained, which is not preferable.
When it exceeds 30,000, the obtained polyamide has a high viscosity at the time of melting and is difficult to melt-mold, which is not preferable.

In the method of the present invention, there is no problem if an inorganic phosphorus compound or the like is added as a polymerization accelerator in the prepolymerization or the postpolymerization, if necessary. As the inorganic phosphorus compound, phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid and their alkali metal salts or alkaline earth metal salts are preferably used. The addition amount of these inorganic phosphorus compounds is usually 100 to 5000 ppm based on the oligomer or polymer to be obtained. When the amount added is out of this range, if it is less than 100 ppm, the addition effect is hardly recognized, and if it exceeds 5000 ppm, the molecular weight of the polymer is remarkably increased, which makes it difficult to melt-form the finally obtained polyamide. However, an unfavorable phenomenon occurs.
The addition method is not particularly limited, and for example, a method of dry blending with a raw material monomer during prepolymerization, or supplying as an aqueous solution during prepolymerization or postpolymerization is suitable.

Further, in order to stabilize the melt viscosity of the obtained polyamide during molding and processing, if necessary, amine or carboxylic acid may be added as a molecular weight modifier during prepolymerization or postpolymerization without any problem. Absent. The amine or carboxylic acid to be added is not particularly limited as long as it is monofunctional and / or bifunctional, and examples thereof include monoamines such as laurylamine, stearylamine, and benzylamine, pentamethylenediamine, hexamethylenediamine, Undecamethylenediamine, dodecamethylenediamine, diamines such as metaxylylenediamine, paraxylylenediamine, acetic acid, benzoic acid, lauric acid, monocarboxylic acids such as stearic acid and adipic acid, pimelic acid, suberic acid, azelaic acid, Suitable examples include dicarboxylic acids such as sebacic acid, dodecanedicarboxylic acid, terephthalic acid and isophthalic acid. The addition amount of these molecular weight regulators is appropriately selected so that the molecular weight (Mn) of the polyamide to be finally obtained is in the range of 7,000 to 30,000 described above.

Furthermore, the polyamide obtained as described above may be added to the polyamide during the production of the oligomer (that is, during prepolymerization) or during the melt polymerization of the oligomer and / or during the solid phase polymerization (that is, during postpolymerization). If necessary, a heat-resistant agent, an antioxidant, a weather-resistant agent, a lubricant, a crystal nucleating agent, an antistatic agent, a pigment, a dye, an anti-blocking agent and the like can be added within a range that does not impair the physical properties.

In the method of the present invention, the polyamide obtained by the above method is molded to produce a gas barrier film suitable as a packaging material for foods, pharmaceuticals or cosmetics. There is no particular limitation on the molding method. For example, a known cast molding method or tubular molding method using an extruder can be applied. In the cast molding method, the T
The polyamide of the present invention can be extruded in a molten state into a film form from a die head, and then cooled and solidified on a casting drum to form the gas barrier film. Further, in the tubular molding method, the polyamide of the present invention is extruded into a tube shape in a molten state from a ring-shaped die head of an extrusion molding machine, followed by blowing air or the like into the tubular body, and then air cooling by an air ring, Alternatively, the gas barrier film can be formed by cooling and solidifying by water cooling by direct contact with water.

[0032]

EXAMPLES The method of the present invention will be described in more detail below with reference to examples and comparative examples. However, the method of the present invention is not limited to these Examples and Comparative Examples as long as the gist thereof is not exceeded. Various properties of the polymer (oligomer and / or polymer) in each of the following Examples and Comparative Examples were measured by the following methods. (1) Relative Viscosity (ηr) According to JIS K6810, 98% by weight concentrated sulfuric acid was used as a solvent and measured at 25 ° C. at a polymer concentration of 1% by weight / volume.

(2) Terminal amino group concentration ([NH ₂ ]) About 1 g of a polymer was dissolved in 40 ml of a phenol / methanol mixed solvent (volume ratio: 9/1), and the obtained sample solution was used as an indicator. Using thymol blue, N /
Titrated with 20 hydrochloric acid.

(3) Terminal carboxyl group concentration ([COO
H]) 40 ml of benzyl alcohol was added to about 1 g of the polymer, and the mixture was heated and dissolved in a nitrogen gas atmosphere, and the obtained sample solution was prepared using phenolphthalein as an indicator.
It was titrated with a N / 20 potassium hydroxide-ethanol solution.

(4) Secondary amine concentration ([NH]) Using 97 wt% of bisulfuric acid as a solvent, a sample solution having a polymer concentration of 20 wt% was prepared.
It was determined from the ¹³ C-NMR spectrum measured at room temperature using M-EX400 type FT-NMR.

(5) Number average molecular weight (Mn) The terminal amino group concentration ([NH ₂ ]) determined by the method described in ( ₂ ) above and the terminal carboxyl group determined by the method described in (3) above. It was determined as the reciprocal of the average value of the concentration ([COOH]).

(6) Gel It was judged by visually observing the presence or absence of a portion insoluble in 98% by weight of concentrated sulfuric acid.

(7) Yellow coloring It was visually determined.

(8) Glass Transition Temperature The glass transition temperature of the sample polymer was measured using a differential scanning calorimeter DSC7 manufactured by Perkin-Elmer Co., which was assayed with 1-heptane and indium. The sample polymer is cooled to -50 ° C by liquid nitrogen, then 10 ° C / m
The temperature was raised up to 200 ° C. at a heating rate of in. During the measurement, the sample polymer was kept under an atmosphere of helium gas supplied at a rate of 30 cc / min.

(9) Melting point The melting point of the sample polymer was measured by using a differential scanning calorimeter DSC-50 manufactured by Shimadzu Corporation, which was calibrated with indium. The sample polymer was heated up to 300 ° C. at a heating rate of 10 ° C./min. During the measurement, the sample polymer was kept under an atmosphere of nitrogen gas supplied at a rate of 30 cc / min.

Example 1 An equimolar salt of metaxylylenediamine and adipic acid was placed in a pressure vessel having a volume of 1 liter equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen gas inlet, a pressure outlet and a polymer outlet. (MXD6 salt) 210 g (0.744 mol), an equimolar salt of hexamethylenediamine and adipic acid (6
6 salt) 90 g (0.343 mol), water 33 g and sodium hypophosphite monohydrate 0.23 g (0.00217).
Mol). Therefore, after thoroughly replacing the inside of the pressure vessel with nitrogen, the temperature was raised in a sealed state with stirring, and prepolymerization was carried out at 210 ° C. for 3 hours. The pressure was adjusted to 9.5 kgf / cm ² G. After the completion of pre-polymerization, collect the polymer (oligomer),
The r, [NH ₂ ] and [COOH] were measured. The measured values are ηr = 1.15, [NH ₂ ] = 85.6 × 10 ^-5 e
q / g and [COOH] = 84.2 × 10 ⁻⁵ eq / g
Met. The Mn of the oligomer is 1178,
[NH] was 1 × 10 ⁻⁵ eq / g.

Next, the pressure inside the pressure vessel is kept at 210 ° C.
To normal pressure, and then 200 cc / m in the container.
With nitrogen gas flowing at a rate of in, raise the temperature to 260 ° C.
Was. When it reaches 260 ℃, its temperature and pressure is 760m.
The polycondensation reaction was allowed to proceed for 2 hours at mHg. After completion of the reaction, stir
Stop the polymerization, and allow the generated polymer to weigh on the bottom of the pressure vessel.
Take out in a string from the compound outlet and immediately cool in a water tank.
After discarding, cut into cylindrical chips and keep at 80 ° C for 72 hours.
Air dried. The resulting polymer is white translucent,
There was no gel. Also, ηr = 3.10, [NH_Two] =
4.6 x 10^-Fiveeq / g and [COOH] = 6.8 ×
10 ^-FiveIt was eq / g. In addition, the glass of this polymer
The transition temperature was 75 ° C and the melting point was 220 ° C. Soshi
This polymer was then fed into an extruder equipped with a T-die
Clew diameter (D) = 18 mm, screw length for D
Ratio (L / D) = 25, barrel temperature = 260
C.], a transparent, homogeneous and good film
Could be molded.

Example 2 The oligomer obtained by carrying out prepolymerization in the same manner as in Example 1 was released into the atmosphere at room temperature to obtain a powdery polymer. Charge this polymer into a pressure vessel of 1 liter capacity,
Solid phase polymerization was carried out at 190 ° C. and a pressure of 1 mmHg for 12 hours. The obtained polymer was white and had no gel. Also, ηr = 2.47, [NH ₂ ] =
8.6 × 10 ⁻⁵ eq / g and [COOH] = 9.3 ×
It was 10 ^-5 eq / g. Furthermore, the glass transition temperature of this polymer was 75 ° C, and the melting point was 220 ° C. Then, this polymer was added to an extruder equipped with a T-die (D
= 18 mm, L / D = 25, barrel temperature = 260 ° C.), a transparent, homogeneous and good film could be formed.

Example 3 The polymer obtained by performing the prepolymerization operation and the postpolymerization operation in the same manner as in Example 1 was charged into a pressure vessel having a volume of 1 liter, and solid phase polymerization was performed at 190 ° C. and a pressure of 1 mmHg for 6 hours. I went. The obtained polymer was white and had no gel. In addition, ηr = 4.17,
[NH ₂ ] = 2.6 × 10 ⁻⁵ eq / g and [COO
H] = 4.3 × 10 ⁻⁵ eq / g. Furthermore, the glass transition temperature of this polymer was 75 ° C, and the melting point was 220 ° C. An extruder equipped with a T-die (D = 18 mm, L / D = 25, barrel temperature =
It was possible to form a transparent, homogeneous and good film by supplying the film at 260 ° C.

Example 4 In the same pressure vessel as in Example 1, 240 g of equimolar salt (MXD6 salt) consisting of metaxylylenediamine and adipic acid.
(0.850 mol), 60 g of ε-caprolactam (0.
531 mol), water 33 g, adipic acid 3.36 g (0.
023 mol) and sodium hypophosphite monohydrate.
293 g (0.00276 mol) was charged. Therefore,
After thoroughly replacing the inside of the pressure vessel with nitrogen, the temperature was raised in a sealed state with stirring, and prepolymerization was carried out at 210 ° C. for 5 hours. Pressure is 13k
It was adjusted to gf / cm ² G. After the completion of the prepolymerization, the polymer (oligomer) is collected and used for ηr, [NH ₂ ] and [COO].
H] was measured. The measured value is ηr = 1.14, [N
H ₂ ] = 84.6 × 10 ⁻⁵ eq / g and [COOH]
= 112.8 x 10 ^-5 eq / g. Further, the Mn of the oligomer is 1013 and the [NH] is 1.5 × 10 5.
^-5 eq / g.

Next, the pressure in the pressure vessel is released to normal pressure at 210 ° C., and then 200 cc / m 2 is fed into the vessel.
The temperature was raised to 260 ° C. while flowing nitrogen gas at a rate of in. When it reaches 260 ℃, its temperature and pressure is 760m.
The polycondensation reaction was allowed to proceed for 4 hours at mHg. After completion of the reaction, stirring was stopped, and the produced polymer was taken out in a string form from the polymer outlet at the bottom of the pressure vessel, immediately cooled in a water tank, cut into cylindrical chips, and vacuum dried at 80 ° C for 72 hours. did. The resulting polymer is white translucent,
There was no gel. Further, ηr = 2.97, [NH ₂ ] =
0.5 × 10 ⁻⁵ eq / g and [COOH] = 16.1
It was × 10 ^-5 eq / g. Further, this polymer had a glass transition temperature of 70 ° C and a melting point of 220 ° C. Then, this polymer was added to an extruder equipped with a T-die (D
= 18 mm, L / D = 25, barrel temperature = 250 ° C.), a transparent, homogeneous and good film could be formed.

Comparative Example 1 Using the same pressure vessel as in Example 1, raw materials were charged in the same manner as in Example 1 and prepolymerization was carried out at 260 ° C. for 1 hour. The pressure was adjusted to 40 kgf / cm ² G. After completion of pre-polymerization,
The polymer (oligomer) was sampled, and ηr, [NH ₂ ] and [COOH] were measured. The measured value is ηr = 1.0
9, [NH ₂ ] = 169.6 × 10 ⁻⁵ eq / g and [COOH] = 180.2 × 10 ⁻⁵ eq / g.
Further, the Mn of the oligomer is 572 and the [NH] is 1
It was 0.5 × 10 ⁻⁵ eq / g.

Next, the pressure in the pressure vessel is released to normal pressure at 260 ° C., and then the temperature and the pressure 760.
The polycondensation reaction was allowed to proceed for 2 hours at mmHg. After completion of the reaction, stirring was stopped, and the produced polymer was taken out in a string form from the polymer outlet at the bottom of the pressure vessel, immediately cooled in a water tank, cut into cylindrical chips, and vacuum dried at 80 ° C for 72 hours. did. The resulting polymer was slightly yellow translucent with some 98 wt% concentrated sulfuric acid insolubles. The glass transition temperature of this polymer is 75 ° C and the melting point is 220 ° C.
Met. Then, this polymer was supplied to an extruder (D = 18 mm, L / D = 25, barrel temperature = 260 ° C.) equipped with a T-die to obtain a transparent film having a rough surface. It was bad.

[0049]

As described in detail above, the method of the present invention is as follows.
Metaxylylenediamine as an essential component, and an aliphatic and / or alicyclic diamine having an alkylene group having 4 to 18 carbon atoms as a diamine component raw material, and a linear aliphatic dicarboxylic acid having 6 to 18 carbon atoms As the raw material for the dicarboxylic acid component, and further contains an aliphatic ω having 4 to 12 carbon atoms.
In a method for producing a polyamide using an aminocarboxylic acid as a raw material, first, an oligomer having a number average molecular weight of 800 or more is produced by prepolymerizing at a temperature of 240 ° C. or lower, and subsequently obtained by using this oligomer. Whether to perform melt polymerization at a temperature higher than the melting point of the polymer by 10 ° C. or higher and 280 ° C. or lower, or solid phase polymerization at a temperature higher than the glass transition temperature of the obtained polymer and lower than the melting point by 10 ° C. or lower. Alternatively, after melt-polymerization at a temperature higher than the melting point of the obtained polymer by 10 ° C. or higher and 280 ° C. or lower, a solid phase is obtained at a temperature higher than the glass transition temperature of the polymer and lower than the melting point by 10 ° C. or lower. A manufacturing method of polymerizing can be provided. Therefore, the polyamide obtained by the production method of the present invention,
Amino group concentration of secondary amine produced by dimerization deammonification reaction between metaxylylenediamine ([N
H]) is substantially suppressed to zero, and it is a polyamide that is homogeneous and has good film-forming property without gelation or yellowing, and can be preferably used as a packaging material for foods, pharmaceuticals, cosmetics and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Amane 1-12-32 Nishimotocho, Ube City, Yamaguchi Prefecture Ube Industries Co., Ltd.

Claims (3)

[Claims] 1. A metaxylylenediamine component unit is contained in an amount of 20 to 100 mol% based on the total amount of the (A) diamine component unit,
And the aliphatic and / or alicyclic diamine component unit having an alkylene group having 4 to 18 carbon atoms is 0 to 8
25 to 50 mol% of the diamine component unit consisting of 0 mol% and 25 to 50% of the linear aliphatic dicarboxylic acid component unit having 6 to 18 carbon atoms as the (B) dicarboxylic acid component unit.
50 mol% and 0 to 50 mol% of (C) aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms
(However, the component unit (A) and the component unit (B) are equimolar%
And the total number of component units (A), (B) and (C) is 100 mol%), the prepolymerization of an oligomer having a number average molecular weight of 800 or more at a temperature of 240 ° C. or less. And then using this oligomer at a temperature 10 ° C. above the melting point of the resulting polymer,
A method for producing a polyamide, characterized in that a polymer free from gel or yellow coloring is obtained by melt-polymerizing at a temperature in the range of 280 ° C or lower. 2. A metaxylylenediamine component unit is contained in an amount of 20 to 100 mol% based on the total amount of the (A) diamine component unit,
And the aliphatic and / or alicyclic diamine component unit having an alkylene group having 4 to 18 carbon atoms is 0 to 8
25 to 50 mol% of the diamine component unit consisting of 0 mol% and 25 to 50% of the linear aliphatic dicarboxylic acid component unit having 6 to 18 carbon atoms as the (B) dicarboxylic acid component unit.
50 mol% and 0 to 50 mol% of (C) aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms
(However, the component unit (A) and the component unit (B) are equimolar%
And the total number of component units (A), (B) and (C) is 100 mol%), the prepolymerization of an oligomer having a number average molecular weight of 800 or more at a temperature of 240 ° C. or less. And then using this oligomer to obtain a polymer free of gel or yellowing by solid-phase polymerizing at a temperature above the glass transition temperature of the resulting polymer and below 10 ° C. below its melting point. A method for producing a polyamide, comprising: 3. A metaxylylenediamine component unit is contained in an amount of 20 to 100 mol% based on the total amount of the (A) diamine component unit,
And the aliphatic and / or alicyclic diamine component unit having an alkylene group having 4 to 18 carbon atoms is 0 to 8
25 to 50 mol% of the diamine component unit consisting of 0 mol% and 25 to 50% of the linear aliphatic dicarboxylic acid component unit having 6 to 18 carbon atoms as the (B) dicarboxylic acid component unit.
50 mol% and 0 to 50 mol% of (C) aliphatic ω-aminocarboxylic acid component unit having 4 to 12 carbon atoms
(However, the component unit (A) and the component unit (B) are equimolar%
And the total number of component units (A), (B) and (C) is 100 mol%), the prepolymerization of an oligomer having a number average molecular weight of 800 or more at a temperature of 240 ° C. or less. And then using this oligomer at a temperature 10 ° C. above the melting point of the resulting polymer,
After melt-polymerizing at a temperature in the range of 280 ° C. or lower, solid-phase polymerization is performed at a temperature in the range of the glass transition temperature of the polymer or higher and 10 ° C. lower than the melting point of the polymer to obtain a polymer free of gel or yellowing. A method for producing a polyamide, comprising: