JPS62252425A - Production of polyamide - Google Patents

Abstract

PURPOSE:To obtain a polyamide of a narrow MW distribution, by polymerizing a specified polymerizable lactam in the presence of a silicate, an alkali catalyst and an activator. CONSTITUTION:A polyamide/silicate composite is obtained by anionically polymerizing 100pts.wt. polymerizable lactam (A) of the formula [wherein n is 6-12, R is H, a 1-8C alkyl or a (substituted) aralkyl] (e.g., caprolactam) at 80-300 deg.C for 1min-5hr in the presence of 0.01-100pts.wt. silicate (B) (e.g., montmorillonite), desirably, swollen with an organic substance (e.g., hexamethylenediamine hydrochloride), 0.01-10mol%, based on component A, alkali catalyst (C) (e.g., NaH) and 0.01-5mol%, based on component A, activator (e.g., N-acetylcaprolactam). This composite is dissolved in a solvent (e.g., m-cresol), and the silicate is removed to obtain a polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a polyamide or a composite of polyamide and silicate having a narrow molecular weight distribution.

[Conventional technology]

Polyamides obtained by polymerizing tuctams are widely used in the fields of fibers, films, resins, etc. Among them, nylon 6, which is produced by hydrolytic polymerization of cabloktam or rapid polymerization using an alkali catalyst, has a position as a typical engineering plastic because of its well-balanced properties.

On the other hand, the present inventors have obtained a composite material with excellent mechanical strength and energizing properties, in which polyamide and silicate are combined at the υ molecular level by polymerizing tscutams in the presence of silicate. (Japanese Patent Application No. 60-217596).

Incidentally, in general, the narrower the molecular weight distribution of plastic materials, the more useful they are in terms of both their material properties and processability, and the more desirable they are in the industrial field. However, in the conventional methods, the obtained polyamides have a weight average molecular weight/number average molecular weight (My/Mn) value of 6 or more, which is an index of molecular weight distribution, and have a wide molecular weight distribution. Furthermore, even with the method discovered by the present inventors, strict conditions are required to obtain a molecular weight that is sufficiently useful as a polymeric material. Specifically, in the case of nylon 6, Kn is 2.0X10
48 to 144 at 250°C to obtain a polymer exceeding
Time is a strict condition.

Narrow molecular weight distributions have been obtained for certain vinyl polymers other than polyamides by the stripping anionic polymerization method and the group transfer 1-polymerization method (New Experimental Chemistry Lecture 119J, Polymer Chemistry (1), p. 198) (1
97B) (published by Maruzen); “Shana A/- Op the American Chemical Society- (Journal
of the, thin 1ricanchanical
8ociety) J, Volume 105, P5706 (
1983) ). However, this method cannot be applied to polyamide.

Soc"t", *□□Yuyo. . After much time and effort, we have arrived at the present invention.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyamide with a narrow molecular weight distribution or a composite of a polyamide and a silicate.

[Structure of the invention]

The method for producing polyamide of the present invention is characterized by polymerizing a monopolymerizable lactam in the presence of a silicate, an alkali catalyst, and an activator.

Below, the configuration of the present invention will be explained in more detail.

In the present invention, the zero-polymerizable lactam is a raw material for polyamide. Examples of the polymerizable lactam include those represented by the following formula [A], which are cyclic compounds,
Sυ, both undergo ring-opening polymerization and decanofuctam (formula [A]
n == 12 e R=H). For example, cabrofuctum, cabrylfuctum, and dodecanofuctum are polymerized to produce nylon 6 and nylon 8. Produces nylon 12. Therefore, the above-mentioned polymerizable lactam is used alone or in an amount of U2m or more.

R (in the formula, n is an integer of 6 to 12, R is hydrogen or carbon number is 1 to
8 is an alkyl group or an aralkyl group. The aralkyl group may or may not have a substituent.

) Furthermore, silicate is thought to produce a polyamide with a narrow molecular weight distribution when a polymerizable lactam is polymerized together with an alkali catalyst.

Furthermore, when a composite with polyamide is formed, it has the function of improving mechanical strength and heat resistance. This composite of silicate and polyamide has a silicate layer 11tllc ho! J
It is thought that the amide enters and the two are combined at the molecular level. That is, it has a structure in which polyamide molecular chains are bridged by ionic bonding with a silicate layer, and is deformed thermally or mechanically. As a result, mechanical properties such as tensile strength and elastic modulus, and heat resistance properties such as softening temperature and high temperature strength become superior.

Examples of the silicates include montmorillonite, permiki islandite, heloysite, etc., and one or more of the silicates are used. However, among the above-mentioned silicates, phyllosilicates such as heptanethorylonite are most preferred.

None. It is preferable to swell the silicate with an organic substance in advance in order to uniformly disperse it in the polymerizable lactam during polymerization. The 11 substances may be hydrocarbons, amines, carboxylic acids, alcohols, halides, etc. as long as they do not inhibit the polymerization of lactam, but they can form strong chemical bonds with silicate due to the degree of cation exchange. . A compound having an onium ion in its molecule is desirable. Specific examples of such organic substances include trimethylamine and triethylamine.

HexvH amine, cyclohexylamine, dodecylamine, aniline, pyridine, benzylamine.

Bis(aminomethy/L/)benzene, aminophenol
, ethylene diamine, hexamethylene diamine.

Hexamethylenetetramine. polyallylamine.

Alanine, 4-aminobutyric acid, 6-aminocaproic acid, 1
Examples include, but are not limited to, strong acid salts such as 2-aminododecanoic acid and 16-amituhexatecanoic acid. Note that the strong acids mentioned here include hydrochloric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and the like. Therefore, the above organic substances may be used alone or in combination of two or more.

The addition t of the above silicate (presence jl when polymerizing the polymerizable lactam) is 0 for 100 parts by weight of the polymerizable lactam.
．． It is preferably within the range of 0.02 to 100 parts by weight. If the amount added is less than 0.01 parts by weight, 1 molecule of the resulting polyamide
The distribution will not be narrow enough. If the amount exceeds 100 parts by weight, the viscosity of the reaction mixture may become high and the reaction rate may decrease. More preferably, it is within the range of 11 to 50 parts by weight.

Also, the presence of an alkaline catalyst and activator.

This is for causing anionic polymerization.

The type and amount of the alkali catalyst and activator added (amounts present during polymerization) may be those used in ordinary anionic polymerization of polymerizable tscutam (for example.

M, I,: 2-hen H,b Nylon Plastics, p 457
, Intersoience
, 1973). Specifically, sodium hydride, sodium methoxide, sodium hydroxide, and sodium amide are used as alkaline catalysts.

Examples include the potassium salt of tscutam. However.

The above alkali catalysts may be used alone or in combination of two or more. Further, the amount of the alkali catalyst added is preferably within the range of 0.01 to 10 mol % based on the zero polymerizable lactam. If the amount added is less than 0.01 mol%, the 1 reaction rate will be low;
If it exceeds 0 mol%.

There is a risk that the molecular weight of the polyamide will decrease.

In addition, the activator has the function of reacting with the alkali catalyst to initiate the polymerization reaction. Examples of the activator include N-acetyl carbloctam, acetic anhydride, carbon dioxide, bulk Examples include cyanuric acid, cyanuric chloride, etc., and one or more of these may be used. Further, the amount of the activator added is preferably within the range of 0.01 to 5 mol % based on the 9-polymerizable lactam. If the amount added is less than 0.01 mol%, the reaction rate will be low, and if it exceeds 5 mol%, the molecular weight of the polyamide may decrease.

In the present invention, polyamide is produced by anionic polymerization, and this anionic polymerization method may be performed under normal conditions.

The polymerization temperature is within the range of 80 to 300°C, so that the polymerization proceeds quickly by heating, but more preferably 120 to 200°C.
The temperature is preferably within the range of 50°C. Further, the polymerization time varies depending on the polymerization temperature, but may be within a range of 1 minute to 5 hours.

In addition, when reacting within the range of 120 to 250°C, 5
~60 minutes is desirable.

In the present invention, additives 9 that do not substantially inhibit the polymerization reaction, such as glass fibers, pigments, antioxidants, etc., may be present.

The polyamide obtained according to the invention, obtained as a composite with a silicate, is 2m-cresol.

By dissolving the polyamide with a solvent such as 1 m-cresol formic acid/chloroform and removing the silicate, it is also possible to obtain a polyamide consisting only of polyamide.

In addition, when it is used as a composite of polyamide and silicate, the present inventors have previously proposed (Patent Application No. 64-2
17196) in which polyamide penetrates between the silicate layers and the silicate and polyamide are composited at the molecular level.

The degree of this compounding can be evaluated by the increase in the distance between zero layers.

The larger the interlayer distance, the higher the mechanical strength and heat resistance.

Generally, the alkali catalyst is located outside the silicate layer, and between the 0 layers there is a hydroxyl group that is thought to react with the alkali catalyst and deactivate the catalyst, so polymerization between the 0 layers will not start or proceed. One possibility is that in the present invention, polymerization progresses, and the interlayer distance tends to increase after polymerization.

[Operation and effect of the invention]

According to the present invention, it is possible to produce a polyamide with a narrow zero molecular weight distribution or a composite of the polyamide and a silicate.

The reaction mechanism by which this polyamide with a narrow molecular weight distribution is obtained is not clear, but the molecular weight distribution of the polyamide is narrowed by the interaction between the silicate present during the polymerization of 9-polymerizable tscutam and an alkali catalyst. it is conceivable that. Furthermore, according to the present invention, polyamide or a composite of silicate and polyamide 1&: can be obtained extremely quickly.

〔Example〕

Below, nine detailed explanations of the present invention will be given.

Example 1 100g of montmorillonite (manufactured by Crimine Kogyo Co., Ltd., trade name "Kunivia FJ") was dispersed in 10e of water, and 51.49g of 12-aminododecanoic acid and 24ml of it were dispersed.
of concentrated hydrochloric acid was added, stirred for 5 minutes, and then filtered. Furthermore, this was thoroughly washed with water and then vacuum dried. This results in 1
Montmorillonite (abbreviated as 12-M) swollen with 2-aminododecanoic acid hydrochloride was prepared.

Next, 100F caprolactam and 1Of the above-mentioned 100% ☆ were placed in a reactor equipped with a stirrer and stirred at 100°C to obtain an extremely viscous homogeneous dispersion.

To this was added 2.41 parts of sodium hydride, followed by 16 parts of sodium hydride.
After raising the temperature to 0℃, ON-
Add acetyl caprolactam.

The mixture was kept at 160°C for 30 minutes to synthesize 9 polymers.

The obtained polymer is post-treated by pulverization, hot water washing, and vacuum drying, and then subjected to GPO (Ge-Vermi-Sheen chromatography).

My/Mn and 29'Mn were measured. The polymer used for GPC measurement was 0.25% by weight of m-creso/
It was measured at 100°C using I/solution. The polymer dissolved easily.

In addition, the interlayer distance of the silicate was measured using a powder X-ray method. Note that the 12-M0 interlayer distance was set at 16A. The above results are shown in the table.

Example 2゜Example 1. Caprolactam was polymerized in the same manner as in Example 1, except that 51 of 12-M was used.

Post-processing was performed and My/Kn, etc. were measured.

The measurement results are shown in the table.

Example 6゜Cabloctam was polymerized in the same manner as in Example 2 except that the polymerization temperature was 225°C, post-treatment was performed, and My/Mn
etc. were measured. The measurement results are shown in the table.

Example 4゜In place of 12-aminododecanoic acid in Example 1, 2
Except that 7.6 f hexamethylene diamine was used and montmorillonite was used 51.

Caprolactam was polymerized in the same manner as in Example 1.

Post-treatment was performed and Mw/Mn etc. were measured.

The measurement results are shown in the table.

Comparative Example 1゜Without using 12-M in Example 1, except for Example 1
Caprolactam was polymerized and post-treated in the same manner as above, and Mw/Mn etc. were measured.

The measurement results are shown in the table.

Comparative Example 2 This comparative example shows an example in which caprolactam was polymerized without using an alkali catalyst or an activator. For the first polymerization, we utilized the fact that the silicate itself has a polymerization effect.

12-459 and caprolactam 100 in Example 1
f and were stirred at 100°C to prepare a viscous homogeneous dispersion. This was heated at 250°C for 96 hours to polymerize caprolactam, and was further post-treated in the same manner as in Example 1.
Measurements such as y/Mn were performed. The measurement results are shown in the table.

In addition, in this comparative example in which no alkaline catalyst was used, the application of the polymer collected during 48 hours during zero polymerization was 1.2X10
The polymerization rate was significantly lower than that of Example 1.

In addition, in Comparative Example 3 in the table, commercially available nylon 6 (Amilan JCM1017J manufactured by Toshisha Co., Ltd.) was used in the same manner as in Example 1, and the Mw
/Mn, etc. are measured. In addition, the amounts of 12-M and alkali catalyst in Table 1 are the polymerizable lactam 10
The amount (parts by weight) used during polymerization is shown relative to 0 parts by weight. Also, 12-Ml in Example 4 is montmorillonite swollen with hexamethylene diamine hydrochloride.

As is clear from the table, it can be seen that a polyamide with a narrow molecular weight distribution can be produced by this example.

Claims (2)

[Claims] (1) A method for producing polyamide, which comprises polymerizing a polymerizable lactam in the presence of a silicate, an alkali catalyst, and an activator. (2) The method for producing a polyamide according to claim (1), wherein the polymerizable lactam is a compound represented by the following formula [A]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [A] (In the formula, n is an integer from 6 to 12, R is hydrogen or has 1 carbon number.
~80 alkyl group or aralkyl group, and the aralkyl group may or may not have a substituent. )