JPS634855B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyamides with high elongation and impact strength. A method of polymerizing an ω-lactam by the action of an alkaline catalyst and a cocatalyst, the so-called alkaline polymerization method, is known. The polyamide obtained by this method is
It has excellent mechanical strength such as tensile strength, bending strength, and initial elastic modulus, and is used as mechanical parts and industrial materials. However, this polyamide has the drawbacks of low elongation and impact strength, and is hard and brittle, so it cannot be used for applications requiring flexibility. Several proposals have been made to improve the elongation and impact strength of polyamides obtained by alkaline polymerization of ω-lactams. For example, British Patent No. 1067153, British Patent No. 1099265, and Japanese Patent Publication No. 43-20475 disclose that a reaction product of a polyol and diisocyanate having a hydroxyl group at the end or side chain of the molecule, A method for obtaining impact-resistant polyamide block copolymers by carrying out alkaline polymerization of ε-caprolactau using polyurethane having isocyanate groups as a cocatalyst is described. However, the impact strength of the resulting polyamide block copolymer is not very high. Furthermore, as is well known, polyurethane used as a co-catalyst has problems with thermal stability and storage stability. Japanese Patent Publication No. 54-40120 discloses a method for producing a terpolymer consisting of a lactam, a polyol, a polyacyllactam or an acyllactam, and modifying the properties of a polyamide. The polyamide obtained by this method has significantly reduced mechanical strength such as tensile strength and tensile modulus. An object of the present invention is to provide a method for producing polyamide that does not have the drawbacks of known methods and has practically sufficient elongation and impact strength. The object of the present invention is to combine an ω-lactam into (1) an alkali catalyst and (2) (a) in a molecule with the formula (In the formula, R represents a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms, and n is an integer of 2 to 11, preferably 5 to 11)
and (b) a compound (B) having at least one hydroxyl group at the end of the molecule or in a side chain, such that the ratio of the number of ureido groups in the compound (A) to the number of hydroxyl groups in the compound (B) is greater than 1 and less than or equal to 2. This is achieved by polymerizing under the action of a co-catalyst obtained by a mixed reaction at a ratio of . The compound (A) and also the co-catalyst used in the present invention have good thermal and storage stability, and the resulting polyamides have high elongation and impact strength. It is well known that when an ω-lactam is polymerized in the presence of a compound having active hydrogen such as an amino group or a hydroxyl group, the polymerization rate and polymerization rate decrease. Considering this, in the present invention,
It should be noted that the polymerization rate and polymerization rate of ω-lactam do not decrease despite the use of a polymer having hydroxyl groups, and this is one of the features of the present invention. Specific examples of ω-lactams to be subjected to polymerization in the present invention include γ-butyrolactam, δ-valerolactam, ε-caprolactam, ω-enantholactam, ω-capryllactam, ω-undecanolactam, and ω-laurinlactam. Examples include.
These omega-lactams may be used alone,
Two or more types may be used in combination. As the alkali catalyst, all compounds used in known alkaline polymerization methods for omega-lactams can be used. Specific examples include alkali metals, alkaline earth metals, their hydrides, oxides, hydroxides, carbonates, alkylated products,
Examples include alkoxides, Grignard compounds, sodium naphthalene, and reaction products of the above metals or metal compounds with ω-lactams, such as sodium salts and potassium salts of ω-lactams. The amount of the alkali catalyst used is preferably 0.05 to 10 mol%, particularly 0.2 to 5 mol%, based on the ω-lactam. Compound (A) can be prepared, for example, by the following method. When R is a hydrogen atom, ω-lactam and toluene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, diisocyanate modified with carbodiimide, polymethylene polyphenyl isocyanate, desmodyur N [ It can be prepared by reacting a polyisocyanate such as [manufactured by Sumitomo Bayer Urethane Co., Ltd.] at a temperature in the range of 160 to 180°C for 1 to 2 hours. When R is an alkyl group or a phenyl group,
It can be prepared by reacting N,N'-diphenyl-p-phenylenediamine or N,N'-dialkyl-p-phenylenediamine with phosgene, and reacting the resulting carbamic acid chloride with an omega-lactam. can. Specific examples of compound (B) include polyethers having one hydroxyl group such as polyoxyethylene dodecyl ether and polyoxyethylene fatty acid ester; hydroxyl groups such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof; Polyethers with 2 hydroxyl groups, polyoxypropylated glycerin, polyethers with 3 hydroxyl groups such as polyoxypropylene triol, polyethylene diol,
Examples include alcohols such as polybutadiene glycol and poly(ε-caprolactone) diol. The molecular weight of compound (B) is preferably 300 to 20,000 from the viewpoint of facilitating dissolution in ω-lactam. The co-catalyst used in the present invention is a compound (A) and a compound
It is prepared by a mixed reaction with (B). Both are based on the number of hydroxyl groups in compound (A) relative to the number of hydroxyl groups in compound (B).
The reaction is carried out at such a ratio that the ratio of the number of ureido groups is greater than 1 and less than or equal to 2, preferably greater than 1 and less than or equal to 1.5. If this ratio is less than 1, it will not be possible to impart sufficient elongation and impact strength to the resulting polyamide, and even if this ratio is made larger than 2, no difference will be observed in the effect, so it is not suitable for industrial use. has no meaning. The reaction temperature is room temperature to the melting point or freezing point of compound (A), preferably 40°C to compound (A).
The temperature is at least 20°C lower than the melting point or freezing point of The reaction between compound (A) and compound (B) proceeds rapidly in the presence of the compound used as an alkali catalyst in the present invention, which has already been described as a catalyst. The amount of this catalyst to be used is preferably 0.01 to 10 gram equivalents, particularly 0.1 to 2 gram equivalents, relative to the hydroxyl group of compound (B). In the case of no catalyst, the reaction rate is very slow and the reaction rate is also poor. Further, both reactions can be carried out in the presence or absence of a reaction solvent such as benzene, toluene, pentane, hexane, heptane, molten ω-lactam, or N-alkylpyrrolidone. Industrially, it is preferable to use a solvent ω-lactam, which does not need to be particularly separated from the reaction product, as the reaction solvent. As shown in the reference example below, the co-catalyst thus obtained has an ester bond formed by ring-opening of the lactam constituting the ureido group in compound (A) and esterification with the hydroxyl group of compound (B). have. Reference Example 44 g of dehydrated amyl alcohol was placed in a 500 c.c. flask equipped with a stirrer and a nitrogen inlet tube, and heated to 100° C. under a nitrogen atmosphere. Add 0.3 g of methylmagnesium bromide (approximately 25% by weight solution in tetrahydrofuran) to this flask,
Dissolved. Next, 4,4'-diphenylmethane biscarbamide ε-caprolactam (obtained by reacting 4,4'-diphenylmethane diisocyanate and ε-caprolactam at 180°C for about 2 hours. Melting point
181-183°C) was added thereto, and the mixture was reacted for 1 hour at the same temperature with stirring. After cooling, add 20g of the reaction mixture to 500g of chloroform.
and mixed and stirred. Approximately 14 g of a compound insoluble in chloroform was obtained. Elemental analysis of this compound,
As a result of analysis by infrared absorption spectrum, the compound had a structure as shown in the following formula. Carbon% Hydrogen% Nitrogen% Theoretical value 68.08 7.80 9.93 Actual value 68.26 7.84 9.96 The present invention uses the above-mentioned cocatalyst and the known cocatalyst N-acyllactam, organic isocyanate, ester, carbodiimide, etc. used in the alkaline polymerization method of lactam. It is also possible to carry out in combination. The alkaline polymerization of ω-lactam in the present invention can be carried out according to a method known per se. The polymerization temperature is higher than the melting point of the ω-lactam to be polymerized and lower than the melting point of the resulting polyamide. Polymerization time is usually 2 hours or less. In the present invention, the lactam can also be polymerized in the presence of stabilizers such as plasticizers, fillers, fibers, blowing agents, dyes, pigments, and antioxidants that do not substantially inhibit the polymerization reaction. Preferred plasticizers include N-alkylpyrrolidones and dialkylimidazolidinones, which have a 2 to 25
It can be used in proportions of % by weight. Fillers include calcium carbonate, wollastonite, kaolin, graphite, gypsum, feldspar, mica, asbestos, carbon black, and molybdenum disulfide, and fibers include glass fibers such as milled glass and graphite fibers. , fibrous magnesium compounds, potassium titanate fibers, mineral fibers, boron fibers, steel fibers, etc. These fillers and fibers can be used in a proportion of 2 to 50% by weight based on the lactam.
In addition, as a blowing agent, benzene, toluene, xylene, etc. are suitable;
It can be used in proportions of % by weight. INDUSTRIAL APPLICATION This invention can be utilized for the method of manufacturing molded articles, such as a round bar, a board, a pipe, and an automobile part, directly from a monomer by a casting method or a reaction injection molding method. It is also possible to form the polymer obtained in the present invention into a molding resin and use it to manufacture molded products, fibers, sheets, etc. by injection molding or extrusion molding. Next, Examples and Comparative Examples will be shown. In the examples and comparative examples, the elongation is
According to ASTMD638-64T, Izotsu impact strength (with notch) is according to ASTM D256-56, respectively.
Measured in an absolutely dry state. The monomer content in the molded product was measured according to JIS K6810. Example 1 700 g of substantially anhydrous ε-caprolactam was placed in a flask and melted at 100°C. Add propylmagnesium bromide (approximately 23% by weight) to this flask.
13.0 g of tetrahydrofuran (used as a tetrahydrofuran solution) was added, and by-produced propane and the solvent tetrahydrofuran were removed under reduced pressure to prepare an alkaline catalyst solution. Anhydrous ε in a separate flask.
-300g caprolactam, dehydrated average molecular weight
1000 polypropylene glycol 200g, 4,
4'-Diphenylmethane biscarbamide ε-caprolactam (reaction product of 4,4'-diphenylmethane diisocyanate and ε-caprolactam) 111.8
A mixture of g and 0.3 g of methylmagnesium bromide was added and mixed at 100° C. for 1 hour to prepare a cocatalyst solution. Mix and stir both liquids and immediately transfer the mixture to a 300mm x 300mm plate preheated to 160°C.
mm, thickness 20mm inner volume mold, mold 160mm
It was kept in an oil bath at ℃ for 1 hour. A test piece was prepared by cutting from the obtained molded article, and its physical properties were measured. The results are shown in Table 1. Comparative Example 1 An experiment was conducted in the same manner as in Example 1, except that polypropylene glycol with an average molecular weight of 1000 and methylmagnesium bromide were not added. The results are shown in Table 1. Comparative example 2 4,4'-diphenylmethane biscarbamide ε-
Other than changing the amount of caprolactam added to 74.5g,
An experiment was conducted in the same manner as in Example 1. but,
The resulting molded product was poorly polymerized and its physical properties could not be measured. Comparative example 3 4,4'-diphenylmethane biscarbamide ε-
Except that 57.6 g of 4,4'-diphenylmethane diisocyanate was added instead of caprolactam.
An experiment was conducted in the same manner as in Example 1. The results are shown in Table 1. However, in Table 1, the symbol - indicates that the measurement was not performed.

[Table] NB indicates that the product did not break when measured by Izot impact strength. Example 2 Instead of polypropylene glycol with an average molecular weight of 1000, 100 g of polypropylene glycol with an average molecular weight of 2000 was added, and 69.9 g of 4,4'-diphenylmethane biscarbamide ε-caprolactam was added.
The experiment was carried out in the same manner as in Example 1, except that each of the two conditions was changed. Table 2 shows the physical properties of the molded product. Example 3 An alkaline catalyst solution was prepared in the same manner as in Example 1. In a separate flask, 300 g of anhydrous ε-caprolactam, 300 g of dehydrated polypropylene glycol with an average molecular weight of 1000, 1 hexamethylene,
A mixture consisting of 132.7 g of 6-biscarbamide ε-caprolactam (a reaction product of hexamethylene diisocyanate and ε-caprolactam) and 0.18 g of methylmagnesium bromide was added, and the mixture was mixed and reacted at 75°C for 1 hour to prepare a cocatalyst liquid. Both solutions were mixed and stirred, and polymerized using the same mold as in Example 1. Table 2 shows the physical properties of the molded product. Example 4 An alkaline catalyst solution was prepared in the same manner as in Example 1. In a separate flask, 300 g of anhydrous ε-caprolactam, 100 g of dehydrated polyoxyethylene dodecamethyl ether (molecular weight 1950), 4.
A mixture consisting of 23.9 g of 4'-diphenylmethane biscarbamide ε-caprolactam and 0.12 g of methylmagnesium bromide was added, and a mixture reaction was carried out at 120° C. for 1 hour to prepare a cocatalyst liquid. Both solutions were mixed and stirred, and polymerized using the same mold as in Example 1. The results are shown in Table 2.

[Table] Example 5 1000 g of substantially anhydrous ε-caprolactam was placed in a flask and melted at 100°C. Add propylmagnesium bromide (approximately 23% by weight) to this flask.
13.0 g of tetrahydrofuran solution (used as a tetrahydrofuran solution) was added, and by-produced propane and the solvent tetrahydrofuran were removed under reduced pressure to prepare an alkaline catalyst solution. To this flask, average molecular weight 2000
Add 300g of polypropylene glycol,
Mix thoroughly under nitrogen atmosphere. Next, N-phenyl-N′-isopropyl-p-phenylenebiscarbamide caprolactam (mp about 215°C)
94.6g was added, mixed and stirred, and the mixture was prepared as Example 1.
Polymerization was performed in the same manner as (ureido group/hydroxyl group ratio: 1.2). The elongation of the molded product is 393%, the isot impact strength (with notches) is 67.4Kg・cm/cm, and the monomer content is
It was 4.6wt%.

Claims (1)

[Claims] 1 ω-lactam is contained in (1) an alkali catalyst and (2) (a) in the molecule with the formula (In the formula, R represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 2 to 11.)
and (b) a compound (B) having at least one hydroxyl group at the end of the molecule or in the side chain, such that the ratio of the number of ureido groups in compound (A) to the number of hydroxyl groups in compound (B) is 1. A method for producing polyamide, characterized in that the polymerization is carried out by the action of a co-catalyst obtained by a mixed reaction at a ratio of 2 or less.