JPS6112728A - Preparation of modified polyamide - Google Patents

Abstract

PURPOSE:To produce a polyol modified polyamide to provide a molded article having improved releasability and high impact strength efficiently in a short time, by subjecting a mixture of lactam and a polyol to anionic polymerization in the presence of a specific activator. CONSTITUTION:(A) 50-95wt% lactam is blended with (B) 50-5wt% polyol, preferably a polyol having 200-10,000, especially 300-5,000 molecular weight, (C) 0.05-30mol%, preferably 0.1-10mol% based on the component A of an activator shown by the formula (Y and Y' are acyl selected from CO, CS, SO, and PO; n and n' are 3-11) obtained by reacting a pyridinedicarboxylic acid halide with lactam in the presence of an amine, and (D) 0.1-10mol%, preferably 0.3-5mol% based on the component A of an ionic polymerization catalyst (e.g., sodium lactamate) in a molten state in an integrated way, fed to a mold, and polymerized, to give the aimed polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a polyol-modified polyamide with excellent impact strength by efficient anionic polymerization.

<Prior Art> Anionic polymerization of lactams using an alkali catalyst and an activator is already a well-known technique, and various molded articles are manufactured using this polymerization method. However, while polyamides obtained by anionic polymerization generally have a high crystallinity and have excellent mechanical strength, abrasion resistance, and fatigue resistance, the problem is that they generally have unsatisfactory impact strength. A method to solve this problem is to obtain a modified polyamide by anionically polymerizing lactam together with all polyols having hydroxyl groups at the terminals, such as polyalkylene glycols, polylactones, and polyolefins (for example, Japanese Patent Publication No. 48 -419
Publication No. 58, Special Publication No. 4941354, Special Publication No. 52
-15139 Publication, Special Publication No. 54-40118,
Special Publication No. 54-40119, Special Publication No. 54-4012
0, Japanese Patent Publication No. 57-17884, etc.) have been proposed.

On the other hand, according to the anionic polymerization method, products can be produced directly from the raw material lactam, so in terms of product productivity, the faster the polymerization rate, the better.a The polymerization rate in anionic polymerization is mainly determined by the activator, but the lactam In order to complete the polymerization of a polyol mixture system in an extremely short period of time, and to fully satisfy the mold release properties, surface appearance, and mechanical properties of the resulting molded product, conventionally known activators do not necessarily provide good results. cannot be obtained, for example,
58 Publication, Special Publication No. 52-15139, Special Publication No. 58
4-40118, Japanese Patent Publication No. 54-'40119, and Japanese Patent Publication No. 57-17884, etc., the polymerization activity is low, and the polymerization activity is low until the polymerization is completed. This is not preferable because it takes an extremely long time. Furthermore, when compounds such as adipoylbislactam, terephthaloylbislactam, and inophthaloylbislactam, which are disclosed in Japanese Patent Publication No. 54-40120, are used as activators, the releasability of molded products is unsatisfactory. However, the surface appearance is also not good, and there is a problem that increasing the amount of activator added to improve the surface appearance leads to a decrease in molecular weight and deteriorates impact strength.

<Problems to be Solved by the Invention> The problem of the present invention is to create molded products with smooth releasable surfaces and high impact strength from lactams and polyols in a short time by efficient anionic polymerization. The purpose is to provide a way to obtain Another object of the present invention is to find an anionic polymerization activator that is effective for obtaining such molded articles.

Means for Solving the Problems> An object of the present invention is to prepare a mixture of lactam, 50 to 95% by weight, and 150 to 5% by weight of polyol in the presence of an activator represented by the following general formula (I). This was achieved by a method for producing modified polyamide characterized by ionic polymerization.

represents an integer. ] The activator used in the present invention can be easily obtained by reacting a pyri:,;/recarboxylic acid halide and a lactam in the presence of an amine. The amount of the activator added during polymerization is suitably within the range of 0.05 to 30 mol%, preferably 0.1 to 10 mol%, based on the lactam monomer. Further, a part of conventionally known activators may be mixed and used.

The lactam used in the present invention is a cyclic amide compound having 4 to 12 carbon atoms, and examples include pyrrolidone, valerolactam, caprolactam, enantholactam, capryllactam, and laurolactam. Further, the polyol used in the present invention has at least two hydroxyl groups and has a molecular weight of 200 to 10.0.
00, preferably from 300 to 000; typical examples thereof include polyethylene glycol, polypropylene glycol, poly(okineethylene/okine propylene) glycol, polytetramethylene glycol, glycerin, and trimethylol. Polyester polyols such as polyether polyols obtained by addition polymerizing ethylene ookinide and/or propylen ookinode to propane and pentaerythritol, poly-ε-caproraft no diol, polybutagenonol, and poly(butarenin/styrene/
) Copolymer-ol and the like. These polyols may be used alone or in combination of two or more.
is possible. The amount of polyol added must be within the range of 5 to 50% by weight based on the total of lactam and polyol. If the amount added is less than 5% by weight, the effect of improving impact strength will be insufficient. On the other hand, if the amount added exceeds 50% by weight, the strength, rigidity, and heat resistance of the resulting polymer will be insufficient, making it difficult to use as a polyamide. It is undesirable because it does not fully demonstrate its characteristics.

The anionic polymerization catalyst used in the present invention is not particularly limited, and commonly known compounds can be used. Representative examples include alkali metals such as sodium lactamate, potassium lactamate and calcium lactamate;
Salts of alkaline earth metals and lactams, or alkaline substances that can react with lactams in the system to form lactamate anions; examples of these are alkali metals, alkaline earth metals, and the hydrogens of these metals. compounds, hydroxides, oxides, carbonates, alkoxy compounds, alkyl compounds, aryl compounds, trialkylaluminiums, Grignard reagents, and the like. Each of these catalysts can be used alone or as a combination of two or more kinds, and the amount added is 0.00% relative to the lactam monomer.
A suitable range is 1 to 10 mol%, more preferably 0.3 to 5 mol%.

There are no particular limitations on the polymerization method and polymerization conditions of the present invention, and conventionally known methods can be employed.

For example, the so-called one-pot method involves melt-mixing the lactam, polyol, catalyst, and activator all at once in one reaction vessel, and then introducing the mixture into a mold for polymerization, or the so-called one-pot method, in which the lactam, polyol, catalyst, and activator are melt-mixed all at once in one reaction vessel, and then the mixture is introduced into a mold and polymerized. Either of the so-called two-pot methods may be used, in which the lactam melt is prepared in two separate containers, the required amounts of both are mixed in a mixer, and then introduced into the mold. The polyol can be added to either the lactam melt containing the catalyst or activator. It is appropriate that the polymerization be carried out at a temperature below the melting point of the lactam monomer and below the melting point of the polymer, particularly preferably at a temperature of 100 to 200°C. The molding method can be carried out using known methods such as non-pressure casting, centrifugal casting, and rotational molding.

The modified polyamide of the present invention may optionally contain glass fibers,
Inorganic or organic fibrous reinforcement materials such as carbon fibers, asbestos fibers, wholly aromatic polyamide fibers, and staples made of boria 2 or polyester having a melting point higher than the polymerization temperature, or talc, wollastenite, calcium carbonate, magnesium oxide, Powdered or spherical fillers such as alumina, mica, glass beads and potassium titanate whiskers can be introduced. The fibrous reinforcement can be used in any form such as milled fibers, chopped fibers, rovings, and mats.

The modified polyamide of the present invention may also contain other ingredients, such as pigments, dyes, flame retardants, heat resistant agents, antioxidants, weathering agents, lubricants, mold release agents, antistatic agents, plasticizers, etc., as long as they do not impair polymerizability or moldability. Agents, nucleating agents, blowing agents and other polymers can be added and introduced.

<Function> The activator used in the present invention is a compound represented by the above-mentioned general formula (I), and is an at least bifunctional compound in which a lactam is bonded to Y and Y' via an anlu group and a pyridine ring. This is a characteristic. In particular, because it is an aromatic ring or a heterocycle containing a heteroatom, it has increased polarity and is more easily soluble in lactams and polyols than compounds consisting of aromatic hydrocarbon rings, which has the advantage of further improving the polymerization rate. It has excellent polymerization activity.

<Example> The present invention will be explained in more detail with reference to Examples below.

The evaluation of the polyamides described in Examples and Comparative Examples was carried out according to the following method.

(I) Tensile properties: ASTM D-638(2)
Bending properties: ASTM D-790 (3) Izot impact strength, ASTM D-256 (4) Heat distortion temperature, ASTM D-648 (5) Surface appearance: Visual judgment reference example (synthesis of activator) Stirrer, nitrogen In a flask equipped with an inlet tube, 1 mol of pyridiso-2,6-recarboxylic acid chloride, 6 mol of ε
-Caprolactam and pyridiso as a hydrogen chloride scavenger were charged and reacted at 120°C for 1 hour under a nitrogen atmosphere. Next, the reaction mixture was poured into a large amount of cold water to precipitate the reaction product, which was separated from P, washed with pure water and methanol in sequence, and dried under vacuum to obtain an off-white powder. The infrared absorption spectrum of this powder has the characteristic -C-N-C- absorption of R (3,400c*-1, 1,700ff-1,1
, 69,0CN-') appeared, and the results of elemental analysis of the powder were as follows, confirming that this compound was pyridinedicarbonyl-biscaprolactam having the following structure.

Elemental Analysis Results Example 1 70% by weight of substantially anhydrous ε-caprolactam and molecules! 4,000 polypropylene glycol 30% by weight
A mixture of sodium caprolactamate and ε-caprolactam was melted and held at 80'C, and sodium caprolactamate was 1 mol % based on ε-caprolactam, and pyridine dicarbonyl biscaprolactam prepared by the method of the reference example was 2 mol % based on ε-caprolactam. % and mix uniformly, immediately heat the mixture to 140°C.
Polymerization was carried out at the same temperature.

Polymerization was completed in about 6 minutes, and test pieces for measuring various physical properties were obtained.

The releasability of the molded product from the mold was good, and the physical properties of the test piece obtained here at an absolutely dry temperature of 23°C are as shown in Table 1, and the rigidity, impact strength, heat resistance, and surface appearance were excellent. It turned out to be the one he gave me.

Comparative Example 1 1 mol % of sodium caprolactamate and 1 mol % of pyridinerecarboxinylbiscaprolactam were added to substantially anhydrous ε-caprolactam, and polymerization was carried out in the same manner as in Example 1. The impact strength of the test piece obtained was 3.4 ky·mouth/(7)·notch, indicating that the molded product was brittle when polyol was used.

Comparative Example 2 40% by weight of substantially anhydrous ε-caprolactam and 60% by weight of the polypropylene glycol used in Example 1
The mixture was polymerized using the same catalyst and activator as in Example 1 under the same conditions. The heat distortion temperature (load 4, 64 kq/d) of the test piece obtained here was 13
It was found that the heat resistance was insufficient.

Comparative Example 3 Polymerization was carried out in exactly the same manner as in Example 1 except that tolylene-2,4-';inocyanate was used in place of the pyridine dicarbonyl biscaprolactam used in Example 1. When the mold was opened after a few minutes, a satisfactory molded product could not be obtained due to the slow polymerization rate.

Example 2 2.4 mol% based on substantially anhydrous ε-caprolactam
of ethylmagneneum bromide was added and uniformly dissolved to obtain a first liquid. On the other hand, to a mixture of 60% by weight of substantially anhydrous ε-caprolactam and 40% by weight of polypropylene glycol having a molecular weight of 2,000, pyridylcarbonylbiscaprolactam obtained by the method of the reference example was added in an amount of 4 mol% based on ε-caprolactam. This was dissolved to obtain a second liquid. The first liquid and the second liquid are stored in separate containers, and the liquid heated and melted at 80°C is transferred using a pump.
After mixing equal amounts of the liquids, they were introduced into a mold heated to 150°C to carry out polymerization. Polymerization was completed in about 5 minutes, and the physical properties of the test piece obtained (polymer composition: nylon 6/polypropylene glycol (80/20% by weight)) were as shown in Table 1, including rigidity, impact resistance, and heat resistance. It has been found that the surface appearance is well-balanced and has extremely high practical value.

Comparative Example 4 Terephthaloyl biscaprolactam was used instead of pyridylcarbonyl biscaprolactam in Example 2, and an attempt was made to dissolve 4 mol% of this terephthaloyl biscaprolactam in ε-cabrolactum, but the solubility was poor. However, a homogeneous solution was not obtained. The second one I got here
The liquid and the first liquid prepared in the same manner as in the example were each transferred in a pot, and the same amounts of the first liquid and the second liquid were mixed in a mixer, and then introduced into a mold heated at 150°C. However, due to the non-uniformity of the second liquid, the reproducibility of the polymerization rate was poor and stable polymerization could not be achieved.

Examples 3 to 5 The physical properties of test pieces obtained by performing the same operations as in Examples 1 to 2 by changing the type and amount of polyol and catalyst added, polymerization conditions, etc. were measured, and the results are shown in Table 1. It was found that materials with excellent performance could be obtained in both cases.

(Blank below on this page) - Effects of the invention> Thus, the activator according to the present invention has excellent polymerization activity in anionic polymerization of lactam and polyol mixed systems, and can efficiently improve mold releasability, surface appearance, and It has the unique effect of providing modified polyamide molded products with excellent mechanical properties such as impact strength. Further, according to the above-mentioned activator of the present invention, for example, Japanese Patent Publication No. 43-19033, Japanese Patent Publication No. 44-16027, and Japanese Patent Publication No. 49-1989
4] It is not necessary to use a modified polyether as shown in Publication 351J, and it is possible to efficiently produce a multi-block copolymer from a normal unmodified polyether and a lactam.

The molded article made of the modified polyamide of the present invention obtained as described above is useful for various mechanical parts, automobile parts, and the like.

Claims (1)

[Claims] A modification characterized by anionically polymerizing a mixture of lactam; 50 to 95% by weight and polyol; 50 to 5% by weight in the presence of an activator represented by the following general formula (I). Method of manufacturing polyamide. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [Here, Y and Y' are ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas, tables, etc. There is an acyl group selected from ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, where n and n' are 3 to
Represents an integer of 11. ]