JPS6131431A - Ultrahigh molecular weight nylon 6 and preparation thereof - Google Patents

Abstract

PURPOSE:Nylon 6, obtained by polymerizing epsilon-caprolactam thermally with a Grignard compound, acyllactam compound and organoaluminum compound, and having ultrahigh molecular weight suitable for special molding and processing, e.g. gel spinning, etc. CONSTITUTION:Subtantially anhydrous epsilon-caprolactam is thermally polymerized with 0.1-3mol%, based on the above-mentioned lactam, Grignard compouund, e.g. megnesium halide lactamate. 0.01-1mol%, based on the above-mentioned lactam, acyllactam compound in the presence of 0.01-3mol%, based on the above-mentioned lactam, organoaluminum compound expressed by the formula RnAlX3-n (R is 1-5C alkyl; X is halogen; n is an iteger 1-3) at 100-200 deg.C temperature to afford the aimed nylon 6 having >=3X10<5> weight-average molecular weight measured by the gel permeation chromatography.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ultra-high molecular weight nylon 6 suitable for special forming processes such as gel spinning, zone stretching, and in-phase extrusion, and a method for producing the same.

<Prior Art> In recent years, research has been actively conducted on molding methods to bring out the ultimate performance (eg, ultimate strength, elastic modulus) of synthetic polymers. It is well known that the strength and elastic modulus of synthetic polymers such as polyolefins, polyamides, and polyesters are greatly influenced not only by the molecular structure of the polymer but also by the molding method. However, molded products such as fibers, films, and plastics only have a level of about 5 to 10% of the theoretical strength and theoretical elastic modulus of polymer materials.

This is mainly due to insufficient molecular orientation in any processed product, and super-stretching, which has been researched in various places in recent years,
Processing methods such as zone stretching, in-phase extrusion, and gel spinning aim to highly orient molecules and bring out ultimate performance close to the theoretical strength and elastic modulus of the polymer. As the development of these processing methods progresses, in order to apply these processing methods, it is essential that the polymer to be processed is linear and its molecular weight is one to two orders of magnitude higher than that of conventional general-purpose products. It has become clear that the higher the molecular weight, the better the results.

Common methods for producing nylon 6 include melt polymerization of ε-caprolactam, a combination of melt polymerization and solid phase polymerization, or anionic polymerization. Among these, melt polymerization involves a process of discharging the polymer from a polymerization iron. However, even if nylon 6 obtained by melt polymerization is further heated under reduced pressure to perform solid phase polymerization, the average molecular weight of the polymer that can be achieved is at most IO to 150,000. This is insufficient to apply special molding methods. ε
-Anionic polymerization of caprolactam is a process in which ε-caprolactam is mainly polymerized in the presence of a basic catalyst and a co-catalyst at a temperature above the melting point of ε-caprolactam and below the melting point of nylon 6, and is used for melt polymerization, surface phase polymerization, etc. It is known that nylon 6 with a higher molecular weight can be obtained by comparison.

However, conventional methods using an alkali metal such as potassium or sodium as a main catalyst and an organic isocyanate compound such as hexamethylene diisocyanate or phenyl isocyanate as a promoter (for example, Japanese Patent Publication No. 41-1943
The weight-average molecular weight of the polymer obtained using the method (No. 9) is about 200,000, which is still not sufficient, and a combination of an alkali metal such as potassium or sodium and a phosphorus halide compound such as phosphorus trichloride or phosphorus pentachloride is used as a catalyst. The polymer obtained by polymerization using this method is a highly cross-linked gelled product that is insoluble in solvents and cannot be molded. In addition, a method for anionically polymerizing ε-caprolactam by combining an alkali metal and N-aluminum-ε-caprolactam to obtain ultra-high molecular weight nylon 6 has been disclosed (for example, Japanese Patent Publication No. 1621/1983). In this case, the weight average molecular weight of the polymer obtained within the range that is soluble in the solvent is at most 25.
The molecular weight level is about 10,000, and has not yet reached a satisfactory molecular weight level.

<Problems to be Solved by the Present Invention> The problem to be solved by the present inventors is to develop polymers with extremely high molecular weight, hitherto unknown, suitable for special molding processes that bring out the ultimate performance of polymers. The object of the present invention is to provide a novel solvent-soluble nylon 6 without cross-linking, and to establish a method for producing the nylon 6 in a short time with high yield.

Means for Solving the Problems> The above problems have been solved by providing a novel ultra-high molecular weight nylon 6 having a mouse average molecular weight of 3XIO' or more as measured by gel permeation chromatography, and Actually, anhydrous ε-caprolactam is mixed with a Grignard compound or a halogenated magnesium lactamate compound in an amount of 0.1 to 3 mol % based on the lactam, and an acyl lactam compound in an amount of 0.01 to 1 mol % based on the lactam. and 0.01-3 mol% relative to the lactam.
General formula RnAlX3-n [where R is an alkyl group having 1 to 5 carbon atoms, X is a halogen i atom, and n is an integer of 1 to 3. ] The problem is solved by providing a method for producing such a novel ultra-high molecular weight nylon 6 by thermal polymerization at a temperature of 100 to 200° C. in the presence of an organoaluminum compound shown in the following.

The present invention will be explained in detail below.

First, the novel method for producing ultra-high molecular weight nylon 6 of the present invention will be explained, and then the obtained ultra-high molecular weight nylon 6 will be explained.

The ultra-high molecular weight nylon 6 of the present invention is obtained by thermally polymerizing substantially anhydrous ε-caprolactam in the presence of a Grignard compound or a halogenated magnesium lactamate compound, an acyllactam compound, and an organoaluminum compound.

The ε-caprolactam used as a raw material can be produced by any method, as long as it is substantially anhydrous.

In order to produce the ultra-high molecular weight nylon 6 of the present invention, selection of the polymerization catalyst is important. In the present invention, Grignard compounds, halogenated magnesium lactamate compounds, acyllactam compounds and organoaluminum compounds are used as polymerization catalysts.

The Grignard compound used in the present invention is a compound obtained by the reaction of a halogenated hydrocarbon and metal magnesium and represented by the general formula 'MgX (in the formula, R' is a hydrocarbon group and X represents a halogen). For example, preferred examples include methylmagnesium iodide, ethylmagnesium bromide, n-butylmagnesium chloride, phenylmagnesium bromide, cyclohexylmagnesium chloride, benzylmagnesium bromide, and allylmagnesium bromide. These Grignard compounds react with ε-caprolactam to produce halogenated magnesium lactamates;
The object of the present invention can be similarly achieved by using a separately synthesized halogenated magnesium lactamate in place of the Grignard compound.

The amount of Grignard compound or halogenated magnesium lactamate compound (hereinafter simply referred to as Grignard compound) used is 0.1 to 3 to ε-caprolactam.
mol %, preferably 0.3 to 1 mol %. If the amount used is less than 0.1 mol %, the polymerization rate will decrease, which is undesirable. On the other hand, if the amount used exceeds 3 mol %, the number of molecules 1 of nylon 6 produced will decrease, which is not preferred.

The acyllactam compound used in the present invention is a compound containing an N-acyllactam unit in the molecule, and the number of N-acyllactam functional groups is preferably 1 to 2 per molecule. Examples of suitable acyllactam compounds include acetylcaprolactam, acetylpyrrolidone, butyrylcaprolactam, benzoylcaprolactam, benzoylpyrrolidone, adiboylbiscaprolactum, adipoylbispyrrolidone, adipoylbislaurolactam, terephthaloylbiscaprolactam, Isophthaloyl biscaprolactam, sebacoyl bispyrrolidone, 2
-chloroterephthaloyl biscaprolactam, 2,5-
Examples include dichloroterephthaloyl biscaprolactam. The amount of acyllactam compound used is ε-
The amount is 0.01-1 mol%, preferably 0.03-0.5 mol%, based on caprolactam. Usage amount is 0.01
If it is less than mol%, the polymerization rate decreases, which is undesirable.
On the other hand, if the amount of stool exceeds 1 mol%, the molecular weight of the produced nylon 6 will decrease, which is not preferable.

General formula RnAlX3-11 used in the present invention (where R is an alkyl group having 1 to 5 carbon atoms, X is a halogen atom,
n represents an integer from 1 to 3. ] Preferred examples of the organoaluminum compound represented by the formula include triethylaluminum, trilobylaluminum, diethylaluminum chloride, di-propylaluminum bromide, ethylaluminum dichloride, n-butylaluminum dabromide, and the like. .

The amount of these organoaluminum compounds used is 0.01 to 3 mol% relative to ε-caprolactam, and 0.03 to 3 mol%.
More preferably, it is 2 mol%. When the amount of organoaluminum compound used is less than 0.01 mol%, the effect of increasing the molecular weight of the produced nylon 6 is small, and when the amount used exceeds 3 mol%, the produced nylon 6 becomes solvent-insoluble. It becomes a gel, which is not desirable.

There are no particular restrictions on the method of adding the Grignard compound, acyllactam compound, and organoaluminum compound, including a method of sequentially adding the Grignard compound, organoaluminum compound, and acyllactam compound to anhydrous molten ε-caprolactam, uniformly mixing, and then heating polymerization; A method in which ε-caprolactam is divided into two parts, a Grignard compound and an organoaluminium compound are added to one side, and an acyllactam compound is added to the other, and the two are mixed and polymerized by heating, or the molten ε-caprolactam is divided into three parts. Grignard compounds, organoaluminum compounds,
Any addition method can be employed, such as a method in which an acyllactam compound is added, the three components are mixed, and the mixture is heated and polymerized.

The polymerization temperature is within the range of 100-200°C.

If the polymerization temperature is less than 100° C., the polymerization rate will drop significantly, and the yield and molecular weight of the produced nylon 6 will both be low, which is not preferable. If the polymerization temperature exceeds 200° C., various side reactions become noticeable and the resulting nylon 6 may become gelled or colored, which is undesirable. The most preferred polymerization temperature is 13
When the polymerization temperature is 0 to 170°C, a high molecular weight polymer can be obtained in a high yield in the shortest time. The polymerization pressure may be normal pressure, increased pressure, or reduced pressure, but normal pressure is preferable.

When carrying out the polymerization of the present invention, a small amount (for example, 30 mol % or less) of other lactam components may be present in the copolymerization, as long as the polymerizability of ε-caprolactam and the physical properties of the resulting polymer are not impaired. Examples of copolymerizable lactams include α-pyrrolidone, α-piperidone, enantholactam, capryllactam, and laurolactam.

In this way, the ultra-high molecular weight nylon 6 of the present invention is obtained.

The ultra-high molecular weight nylon 6 of the present invention is nylon 6 having a weight average molecular weight of 3X, 105 or more as measured by gel permeation chromatography. The measurement conditions by gel permeation chromatography used in the present invention are not particularly limited, but the weight average molecular weight is usually measured under the following measurement conditions.

Solvent: Metacresol/chloroform = 30/70
Container specific flow rate: 11t/string temperature: 25°C Sample concentration: 0.2 wt% Conventional nylon 6 has a weight average molecular weight of less than 3 x 10' as measured by gel permeation chromatography, and the present invention Thus, a new ultra-high molecular weight nylon 6 could be provided. Moreover, conventional nylon 6 tends to become less soluble or insoluble in organic solvents (for example, m-cresol) as the molecular weight increases, but the ultra-high molecular weight nylon 6 of the present invention is soluble in organic solvents. This is because, although the ultra-high molecular weight nylon 6 of the present invention has a large molecular weight, the molecule is linear and has almost no cross-chain bonds. Although the specific microstructure is unknown, it can be presumed that the ultra-high molecular weight nylon 6 of the present invention has a microstructure different from that of conventional nylon 6.

Effect> In producing ultra-high molecular weight nylon 6 in the present invention, it is extremely important to use a mixed catalyst system of three components: a Grignard compound, an acyllactam compound, and an aluminum compound represented by RnAls-n.

This is because in the case of a combination of Grignard compounds and acyllactam compounds, the weight average molecular weight of the resulting polymer is at most 200,000 to 250,000, which is an unsatisfactory degree of polymerization; In the combination of a lactam compound and an aluminum compound, the polymerization rate is very slow, and nylon 6 with a low degree of polymerization can only be obtained in a low yield. Furthermore, when an alkali metal or its derivative is used instead of a Grignard compound, the nylon 6 produced becomes a solvent-insoluble gel, which is undesirable.On the other hand, when an organic isocyanate compound is used instead of an acyllactam compound, the polymerization rate is is extremely reduced, making it impossible to efficiently produce the desired high molecular weight nylon 6.

The ultra-high molecular weight nylon 6 of the present invention is a Grignard compound,
This became possible for the first time by using a mixed catalyst system that combines an acyllactam compound and an organoaluminum compound.

<Example> The present invention will be explained in more detail by giving examples below. In the following examples, the weight average molecular weight expressed as MW' was measured using a GPC-244 gel permeation chromatograph manufactured by WATER 8 under the following conditions.

Solvent: Metacresol/Chloroform = 30/70 Volume specific flow rate = 1 t/1000 IR Temperature = 25 °C Sample concentration: 0.2 wt% Example 1 Anhydrous ε-caprolactam 56.5F (0.5 mol )'' was divided into two equal parts and kept at 90°C in a test tube, and one part was mixed with ethylmagnesium bromide (3.0 mol/1! ether-soluble F&
)0. ．． 0025 mol (0 for ε-caprolactam)
．． 5 mol%) and triethylaluminum 0.000
5 mol (O, 1 mol % based on ε-caprolactam) was added, and the ether was distilled off under reduced pressure to obtain a liquid A. On the other hand, adipoyl biscaprolactam O, 168F (ε-
0.1 mol % based on caprolactam) was added and dissolved to obtain Solution B. Next, liquid A and liquid B were mixed to form a homogeneous solution, and this was immersed in an oil bath at 140°C for polymerization. Polymerization was completed in 20 minutes, with a yield of 97% of white rod-shaped polymer.
．． Obtained at 3%. The MW of this polymer is 7.8X105
Met. This polymer was also dissolved in m-cresol at room temperature.

Comparative Example 1 Anionic polymerization of ε-caprolactam was carried out in the same manner as in Example 1 except that triethylaluminum was not added. The polymerization was completed in 45 minutes and a white rod-shaped polymer was obtained, but the MW of this polymer was 2. .1X10B,
The degree of polymerization was unsatisfactory.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that ethylmagnesium bromide was not added.
Almost no polymerization occurred even after hours, and only a polymer with a low yield and degree of polymerization (MW: 5X1O'') was obtained.

Comparative Example 3 Anhydrous molten ε-caprolactam was divided into two equal parts, and 0.5 mol% of ethylmagnesium bromide relative to the lactam was added to one half, and triethylaluminum of 0.1 mol% relative to the lactam was added to the other. , both were mixed and heated to 140°C.
Although polymerized for a long time, the degree of polymerization of the obtained polymer is extremely low (
The MW was l x 103).

Example 2 Anhydrous molten ε-caprolactam is divided into two equal parts and one is charged with 1.0 mole % cyclohexylmagnesium chloride based on the lactam and 0.3 mole % diamy propylaluminum chloride based on the lactam. The solvent was distilled off under reduced pressure to obtain liquid A. On the other hand, terephthaloyl biscaprolactam was added in an amount of 0.25 mol % based on the lactam to obtain a B solution. Mix A liquid and B liquid uniformly and heat to 140℃.
When polymerization was carried out, the polymerization was completed in 35 minutes, the yield of the polymer obtained here was 96.5%, and the MW was 6.8X1.
It was 0'. This polymer was also dissolved in m-cresol at room temperature.

Examples 3 to 7 Table 1 shows the results of polymerizations conducted with different types and amounts of Grignard compounds, acyllactam compounds, and organoaluminum compounds. In either case, nylon 6 having a sufficiently high molecular weight was obtained in a short time in high yield.

All of the obtained polymers were dissolved in m-cresol at room temperature.

JP-A-Sho Gl-31431 (6) <Effects of the Invention> The present invention has made it possible to provide a novel ultra-high molecular weight nylon 6 suitable for special forming processes such as gel spinning and zone stretching. Furthermore, the method of the present invention enables production in a short time and with high yield. The molecular weight of the ultra-high molecular weight nylon 6 obtained by the present invention is at an extremely high level, which has not been disclosed at all so far, and the present invention is characterized in that a novel ultra-high molecular weight nylon 6 can be produced.

Claims (2)

[Claims] (1) Ultra-high molecular weight nylon 6 having a weight average molecular weight of 3 x 10^5 or more as measured by gel permeation chromatography. (2) substantially anhydrous ε-caprolactam, a Grignard compound or halogenated magnesium lactamate in an amount of 0.1 to 3 mol % based on the lactam, and an acyl lactam in an amount of 0.01 to 1 mol % based on the lactam; 0.01 to 3 mol% of the compound and the lactam of the general formula RnAlX_3_-_n [where R is an alkyl group having 1 to 5 carbon atoms, X is a halogen atom, and n is an integer of 1 to 3]. 1 in the presence of an organoaluminum compound represented by
A method for producing ultra-high molecular weight nylon 6 having a weight average molecular weight of 3 x 10^5 or more as measured by gel permeation chromatography, characterized by carrying out thermal polymerization at a temperature of 00 to 200C.