JPS6356889B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyol-modified polyamide with excellent impact strength by efficient anionic polymerization. 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, although polyamides obtained by anionic polymerization generally have a high degree of 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 a lactam together with a polyol having a hydroxyl group at the end, such as polyalkylene glycol, polylactone, or polyolefin (for example, Japanese Patent Publication No. 48-41958). Publication, Special Publication No. 4-41354,
Japanese Patent Publication No. 52-15139, Publication No. 40118-40118, Publication No. 40119-198, Publication No. 40120-1980, Publication No. 17884-1977, etc.) have been proposed. On the other hand, according to the anionic polymerization method, products can be produced directly from the raw lactam, and therefore, in terms of product productivity, the faster the polymerization rate, the better. The polymerization rate in anionic polymerization is mainly determined by the activator, but the polymerization of the lactam and polyol mixture system can be completed in an extremely short time, and the surface appearance and mechanical properties of the resulting molded product are fully satisfied. For this purpose, conventionally known activators do not necessarily give good results. For example, Special Publication No. 41958, Publication No. 41958, Special Publication No. 41958, Publication No. 41958, Special Publication No. 41958,
Publication No. 15139, Special Publication No. 1984-40118, Special Publication No. 1973
In the methods using an isocyanate compound as an activator, such as those disclosed in Japanese Patent Publication No. 40119 and Japanese Patent Publication No. 57-17884, the polymerization activity is low and it takes a very long time to complete the polymerization. Furthermore, when compounds such as adipoylbislactam, terephthaloylbislactam, and isophthaloylbislactam shown in Japanese Patent Publication No. 54-40120 are used as activators, the releasability of the molded product is unsatisfactory. The surface appearance is also not good, and when the amount of activator added is increased to improve the surface appearance, the molecular weight decreases and the impact strength deteriorates. Therefore, the present inventors conducted extensive research on a method for obtaining molded products made of lactam and polyol with a smooth surface and high impact strength by efficient anionic polymerization in a short period of time, and found that a specific compound could be used as an activator. The present invention was achieved by discovering that the objects can be achieved all at once by doing the following. That is, the present invention provides a modified polyamide 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 (). It provides a manufacturing method. Here, R ₁ in the formula is a divalent organic group, R ₂ and R ₃
is hydrogen, an alkyl group having 1 to 10 carbon atoms, and 4 to 10 carbon atoms.
At least one group selected from 15 cycloalkyl groups and aryl groups having 6 to 15 carbon atoms, X and X' are

【formula】 【formula】 【formula】

The group selected from the formula: n and n' represent integers from 3 to 11. The activator used in the present invention is a compound represented by the above general formula (), in which the lactam is
It is characterized in that it is an at least bifunctional compound bonded via the groups represented by and X′, the amino groups represented by --NR ₂ -- and --NR ₃ --, and the organic group represented by R ₁ . This activator has excellent polymerization activity in the anionic polymerization of mixed systems of lactams and polyols when used in smaller amounts than conventionally known activators, and can efficiently improve mold releasability, surface appearance, impact strength, etc. in a short time. It has the unique effect of producing modified polyamide molded products with excellent mechanical properties.
Furthermore, according to the above-mentioned activator of the present invention, there is no need to use modified polyethers such as those disclosed in Japanese Patent Publications No. 43-19033, Japanese Patent Publication No. 44-16027, and Japanese Patent Publication No. 49-41354, It is possible to efficiently produce multiblock copolymers from unmodified polyethers and lactams. The activator of the present invention can generally be synthesized by the following method. That is, it can be obtained by adding a lactam to an isocyanate compound, a thioisocyanate compound, etc., or by reacting a compound having a secondary amino group with phosgene, thiophosgene, sulfonyl dichloride, or phosphoryl dichloride, and then adding a lactam. For example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate,
1,11-undecamethylene diisocyanate,
1,12-dodecamethylene diisocyanate, β-
Methyl butane diisocyanate, butene diisocyanate, ω, ω'-dipropyl ether diisocyanate, 1,4-butanediol dipropyl ether diisocyanate, thiodiethyl diisocyanate, ω, ω'-diisocyanate-1,
3-dimethylbenzene, ω,ω'-diisocyanate 1,2-dimethylbenzene, ω,ω'-diisocyanate-1,2-dimethylcyclohexane, ω,ω'-diisocyanate-1,4-dimethylcyclohexane, ω,ω' -diisocyanate-1,4-diethylbenzene, ω,ω'-diisocyanate-1,4-dimethylnaphthalene,
ω,ω′-diisocyanate-1,5-dimethylnaphthalene, 1-ω-methylisocyanate-2
-ω-Propylisocyanate-3,5-dimethylcyclohexaneω,ω'-Diisocyanate-
n-propyl-biphenyl, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-, 2,5-, 2,6-, 3,
5-Tolylene diisocyanate, 1,3-dimethylbenzene-2,4-diisocyanate, 1,3
-dimethylbenzene-4,6-diisocyanate, 1,4-dimethylbenzene-2,5-diisocyanate, naphthalene-1,4-, 1,5-,
2,6-, 2,7-diisocyanate, 1,1'-
dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-, 4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate,
2,2'-dimethyldiphenylmethane-4,4'-diisocyanate, cyclohexyl-(4-isocyanate phenyl)methane, dicyclohexylmethane-4,4'-diisocyanate, 3,3'-dimethoxydiphenylmethane-4, By adding pyrrolidone, ε-caprolactam, ω-laurolactam to 4'-diisocyanate, benzophenone-3,3'-diisocyanate, α,β-diphenylethane-2,4-diisocyanate, or their corresponding thioisocyanate compounds. The synthesized compound and N,N'-dimethyl-1,
4-tetramethylenediamine, N,N'-dimethyl-1,6-hexamethylenediamine, N,
N'-diethyl-1,6-hexamethylenediamine, N-methyl-N'-propyl-1,6-hexamethylenediamine, N,N'-dimethyl-1,
4-Cyclohexanediamine, N,N'-dimethyl-methaxylylenediamine, N,N'-dicyclohexyl-paraxylylenediamine, N,
At least one compound selected from the compounds synthesized by reacting N'-diphenyl-paraphenylenediamine with phosgene or thiophosgene to form bischloroformate and then further adding pyrrolidone, caprolactam, etc. is used as an activator. It is most commonly used as Each of these activators can be used alone or in the form of a mixture, and a portion of conventionally known activators may be mixed. The amount of the activator added is suitably within the range of 0.05 to 30 mol%, preferably 0.1 to 10 mol%, based on the lactam monomer. The lactam used in the present invention has 4 to 12 carbon atoms.
Examples include pyrrolidone, valerolactam, caprolactam, enantholactam, capryllactam, and laurolactam. Furthermore, the polyol used in the present invention has at least two hydroxyl groups and has a molecular weight of 200 to 10,000, preferably 300.
~5000, typical examples of which include polyethylene glycol, polypropylene glycol, poly(oxyethylene/oxypropylene) glycol, polytetramethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc., with ethylene oxide and Examples include polyether polyols obtained by addition polymerization of/or propylene oxide, polyester polyols such as polyε-caprolactone diol, polybutadiene diol, and poly(butadiene/styrene) copolymer diols. These polyols can be added alone or in combination of two or more. The amount of polyol added is suitably within the range of 5 to 50% by weight relative to 95 to 50% by weight of lactam. If the amount of polyol added is less than 5% by weight, the effect of improving impact strength will be insufficient, while if the amount of polyol added exceeds 50% by weight, the strength, rigidity, and heat resistance of the resulting polymer will be insufficient, and the characteristics as a polyamide will be insufficient. This is not desirable because it does not allow for sufficient performance. The anionic polymerization catalyst used in the present invention is not particularly limited, and commonly known compounds can be used. Typical examples are salts of lactams with alkali metals and alkaline earth metals such as sodium lactamate, potassium lactamate, and calcium lactamate, or alkaline salts that can react with lactams in the system to form lactamate anions. Substances such as alkali metals, alkaline earth metals and their hydrides, hydroxides, oxides, carbonates, alkoxy compounds, alkyl compounds, aryl compounds or trialkylaluminiums, Grignard reagents, etc. can be mentioned. Each of these catalysts can be used alone or as a mixture of two or more, and the amount added is 0.1 to 10 mol% based on the lactam monomer.
More preferably, the range is 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 two-pot method, in which the lactam, polyol, catalyst, and activator are melt-mixed all at once, and then introduced into a mold for polymerization; In the case of the two-pot method, either of the so-called two-pot methods may be used, in which two lactam melts are 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 temperature be carried out in a range above the melting point of the lactam monomer and below the melting point of the polymer, 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 inorganic or organic fibrous reinforcing materials such as staples made of glass fiber, carbon fiber, asbestos fiber, wholly aromatic polyamide fiber, polyamide having a melting point higher than the polymerization temperature, polyester, etc. Alternatively, powdered or spherical fillers such as talc, wollastenite, calcium carbonate, magnesium oxide, alumina, mica, glass beads, and potassium titanate whiskers can be introduced. The fibrous reinforcement can be used in any shape such as milled fiber, chopped fiber, roving, or mat shape.
In addition, the modified polyamide of the present invention may contain other ingredients as long as they do not impair polymerizability and moldability, such as pigments, dyes, flame retardants, heat resistant agents, antioxidants, weathering agents, lubricants, mold release agents, and antistatic agents. , plasticizers, crystal nucleating agents, blowing agents, other polymers, etc. can be added and introduced. The molded article made of the polyamide of the present invention obtained as described above is useful for various mechanical parts, automobile parts, etc. The present invention will be explained in more detail with reference to Examples below. The polyamides described in the Examples and Comparative Examples were evaluated according to the following method. (1) Tensile properties: ASTM D638 (2) Bending properties: ASTM D790 (3) Izot impact strength: ASTM D256 (4) Heat distortion temperature: ASTM D648 (5) Surface appearance: Visual judgment Example A Synthesis) 1 equivalent of hexamethylene diisocyanate and 4 equivalents of anhydrous caprolactam were placed in a three-neck flask equipped with a stirring blade, a thermometer, and a nitrogen inlet.
After purging with nitrogen, the mixture was heated and reacted at 110-120°C for 2 hours with stirring. A solution of this reaction mixture was poured into a large amount of cold water to precipitate the reaction product as a white precipitate, which was separated, washed three times with pure water to remove excess caprolactam, dried under vacuum, and dried to a melting point of A white powder was obtained with a temperature of 81-83°C. The IR spectrum of this white powder has no isocyanate group absorption (2270 cm ^-1 ), but instead imide group absorption (2270 cm -1 ).
Absorption of NH.carbonyl group (3240cm ^-1 , 1710cm ^-1 )
appears strongly, and this compound has the following structure bis(caprolactam-N-carboxylic acid)-1,6
- Confirmed that it was hexamethylene diamide. Example 1 A mixture of 80% by weight of substantially anhydrous ε-caprolactam and 20% by weight of polypropylene glycol having a molecular weight of 2000 is heated and melted at 80°C, and sodium caprolactamate is added at 1 mol% relative to ε-caprolactam. and bis(caprolactam-N-carboxylic acid)-1 prepared by the method of Example A,
After adding 1 mol% of 6-hexamethylene diamide to ε-caprolactam and mixing uniformly,
Immediately pour the mixture into a mold kept at 140℃,
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 when the physical properties of the test piece obtained here were evaluated at absolute dry temperature at 23°C, it was found that
As shown in the table, it was found to have excellent rigidity, impact strength, heat resistance, and surface appearance. Comparative Example 1 1 mol % of sodium caprolactamate and 1 mol % of bis(caprolactam-N-carboxylic acid)-1,6-hexamethylenediamide were added to substantially anhydrous ε-caprolactam, and the same procedure as in Example 1 was carried out. Polymerization was carried out. The impact strength of the test piece obtained here was as follows, and it was found that the molded product was brittle when no polyol was used. Izot impact strength: 3.5 Kg・cm/cm Notch Comparative Example 2 Substantially anhydrous ε-caprolactam 40% by weight and polypropylene glycol 60 used in Example 1
The weight percent mixture was polymerized using the same catalyst and activator as in Example 1 and under similar conditions. The heat distortion temperature of the test piece obtained here was as follows, and it was found that the heat resistance was insufficient. Heat deformation temperature (load: 4.64Kg/cm ² ): 130℃ Comparative example 3 The screw used in Example 1 (caprolactam-N-
When polymerization was carried out in the same manner as in Example 1 except that hexamethylene diisocyanate was used instead of (carboxylic acid)-1,6-hexamethylene diamide, it took 20 minutes to complete the polymerization, and the activator was It was found that the polymerization activity was lower than that of Example 1. Comparative Example 4 Bis(caprolactam-N-
Polymerization was carried out in exactly the same manner as in Example 1, except that adipoyl bisprolactam was used instead of carboxylic acid)-1,6-hexamethylene diamide,
When the mold was opened about 6 minutes after the start of polymerization, it was found that a molded article with an excellent surface appearance could not be obtained because the polymerization rate and solidification rate of the molded article were slow. Example 2 70% by weight substantially anhydrous ε-caprolactam and 1000 molecular weight polytetramethylene glycol 30
A mixture of 1% by weight of potassium lactamate with respect to ε-caprolactam and ε of bis(caprolactam-N-carboxylic acid)-1,6-hexamethylene diamide prepared by the method of Example A
- After adding 2 mol % to caprolactam and uniformly dissolving and mixing, polymerization was carried out in the same manner as in Example 1. Polymerization was completed in about 15 minutes, and the physical properties of the test pieces obtained were as shown in Table 1. Example 3 Sodium caprolactamate was added to a mixture of 60% by weight of substantially anhydrous ε-caprolactam and 40% by weight of polypropylene glycol having a molecular weight of 1000.
- 2.7 mol% of caprolactam was uniformly dissolved to form the first liquid. On the other hand, bis(caprolactam-N-carboxylic acid)-1,6-hexamethylene diamide obtained by the method of Example A was added to substantially anhydrous ε-caprolactam.
A second liquid was prepared by dissolving 3.2 mol%. The first liquid and the second liquid are stored in separate containers, and the liquid heated and melted at 80°C is transferred by a pump, and the first liquid and the second liquid are transferred by a mixer.
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 15 minutes, and the resulting polymer was N-6/PPG.
It has a composition of 1000 = 80/20wt%, and the physical properties of the test specimen are shown in Table 1, and it was found that it has a balance of rigidity, impact resistance, heat resistance, and surface appearance, and has extremely high practical value. . Example 4 Each of the first liquid and second liquid described in Example 3
100 parts by weight, and 60 parts by weight of medium glass fiber (diameter 13 microns, length 200 microns),
Polymerization was carried out in the same manner as in Example 3 to obtain a molded piece. The physical properties of the test piece obtained here are as shown in Table 1, and it was found that it has extremely high practical value.

【table】

[Table] Examples 5 to 8 Physical properties of test pieces obtained by performing the same operations as Examples 1 to 4 by changing the type of activator, the type and amount of lactam and polyol added, polymerization conditions, etc. Upon measurement, the results shown in Table 2 were obtained. In all cases shown in Table 2, materials with excellent performance could be obtained.

【table】

【table】

Claims (1)

[Claims] 1. Lactam: 50 to 95% by weight and polyol: in the presence of an activator represented by the following general formula ():
A method for producing a modified polyamide, which comprises anionically polymerizing a 50 to 5% by weight mixture. Here, R ₁ in the formula is a divalent organic group, R ₂ and R ₃
is hydrogen, an alkyl group having 1 to 10 carbon atoms, and 4 to 10 carbon atoms.
At least one group selected from 15 cycloalkyl groups and aryl groups having 6 to 15 carbon atoms, X and X' are groups selected from [Formula] [Formula] [Formula] and [Formula], n and n ' represents an integer from 3 to 11.