JP2677364B2 - Method for producing polyamide - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a polyamide in which polyhexamethylene adipamide has a significantly structured melt thermal stability. [Prior Art] Polyamides having adipic acid as one reactant, such as polyhexamethylene adipamide, generally have poor thermal stability and easily form a three-dimensional insoluble and infusible gel. The formation of this gel reduces the heat transfer in the polymerization process,
It causes various problems such as increase of yarn breakage in the spinning process and generation of black foreign matter in the polymer. Various methods have been studied in order to suppress the gelation, but these methods mainly include the method of incorporating a phosphorus compound. For example, JP-B-45-11836 discloses a pyrophosphite, JP-B-4535667 discloses an amide compound of an organic phosphinic acid, and JP-B-45-12986 discloses a mono- or diester of phosphorous acid. Salt
38351 discloses a method of incorporating a barium salt of a mono- or diester of phosphorous acid and orthophosphoric acid, and Japanese Patent Publication No. 46-38532 discloses a method of adding a copper salt of a mono- or diester of orthophosphoric acid. In addition,
24297 discloses that a phosphorus compound selected from a phosphinic acid compound and a phosphonous acid compound is added to a polyamide in an amount of 50 to 10
A method of blending 00 ppm by weight and an alkali compound selected from alkali hydroxides and alkyl alcoholates in a molar ratio of 1 to 5 times that of phosphorus compounds. JP-B-51-25065 discloses a polyamide containing a phosphinic acid compound and a phosphinic acid compound. Compounds selected from phosphonic acid compounds and phosphorous acid compounds
50-1000 ppm by weight of alkali hydroxide, alkyl alcoholate, alkylphenolate, alkali carbonate and dicarboxylic acid anhydride, or a method of adding a hydrolyzate thereof, Japanese Patent Publication No. 51-25066 discloses that polyamide is phosphinic acid. Compounds, compounds selected from phosphinic acid compounds, phosphonic acid compounds and phosphorous acid compounds 50 to 1000 weight
ppm, an alkali compound selected from an alkali hydroxide, an alkyl alcoholate, an alkylphenolate and an alkali carbonate and a compound of 1 to 5 times mol of a phosphorus compound and 0.01 to 2% by weight of an o-phenylenediamine derivative, JP-B-51.
-41906 gazette, a compound selected from a phosphonic acid compound and a phosphorous acid compound in polyamide 50-1000 wt ppm
And an alkali compound selected from alkali hydroxide and alkyl alcoholate are blended in a molar amount of 1 to 5 times that of the phosphorus compound. [Problems to be Solved by the Invention] However, when the phosphorus compound is added in a small amount, it has a slight gelation-inhibiting effect, but when it is added in a large amount, it rather promotes gelation. In addition, 3 in polyhexamethylene adipamide
It hardly suppresses the formation of bishexamethylenetriamine, which is the main component of dimensionality. Alkali hydroxide has an effect of preventing gelation but inhibits polymerization. Alkali carbonate also has an effect of preventing gelation, but due to the carbon dioxide gas generated upon addition, foaming is observed in the polymer, and yarn breakage frequently occurs during spinning. Therefore, an object of the present invention is to provide a polyhexamethylene adipamide having a sufficient gelation-inhibiting inhibitory effect, a polymerization inhibiting property, and a low polymer foaming property in the polymerization of a polyamide containing polyhexamethylene adipamide as a main component. It is to provide a manufacturing method. [Means for Solving the Problems] The above object of the present invention is to provide 0.2 g to 4 mmol of dicarboxylic acid or aminocarboxylic acid as an alkaline component to 100 g of polyamide containing polyhexamethylene adipamide as a main component. It is achieved by a method for producing a polyamide, which comprises polymerizing by incorporating a mono- or dialkali salt (excluding Li). The polyhexamethylene adipamide referred to here is made using adipic acid as the acid component and polymethylene diamine such as tetramethylene diamine, hexamethylene diamine, octamethylene diamine, decamethylene diamine, dodecamethylene diamine, etc. as the diamine component. Refers to polyamide. The polyamide used in the present invention may be not only such polypolymethylene adipamide but also modified polypolymethylene adipamide having 20% by weight or less of other amide-forming units. Examples of such a small amount of amide-forming unit include fatty acid dicarboxylic acids such as sebacic acid and dodecanoic acid; aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; aliphatic diamines such as polymethylenediamine; aromatic compounds such as metaxylylenediamine. Group diamine; ε-
Ω-aminocarboxylic acids such as aminocaproic acid; lactams such as caprolactam and laurinlactam can be used.
It is also possible to use a blend in which the above polypolymethylene adipamide is blended with 20% by weight or less of another polyamide. The polyamide containing polyhexamethylene adipamide as the main component is an additive usually used for polyamides, for example, a heat stabilizer such as copper acetate, copper chloride, copper iodide, mercaptobenzimidazole; manganese lactate, It may contain a light stabilizer such as manganese phosphite; a matting agent such as titanium dioxide or kaolin; a lubricant such as ethylene bisstearylamide or stearate, and a plasticizer. As the dicarboxylic acid, adipic acid; aliphatic dicarboxylic acids such as sebacic acid and dodecanoic acid; aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid are used, and as the aminocarboxylic acid, γ-aminobutyric acid; β-aminobutyric acid; δ
-Aminovaleric acid; γ-aminovaleric acid; ε-aminocaproic acid and the like are used. The amount of mono- or dialkali salt of dicarboxylic acid or aminocarboxylic acid added is 0.2 to 4 mmol per 100 parts by weight of polyamide. Preferably 0.4 mmol to 2
Millimoles. If it is less than 0.2 mmol, the gelation-inhibiting effect is small, and if it exceeds 4 mmol, not only the effect is saturated, but also the polymerization inhibiting property becomes large. As the alkali salt, Na, K, Rb and Cs salts are used. No gelation suppressing effect is observed for Li salt. The mixing time of the mono- or dialkali salt of dicarboxylic acid or aminocarboxylic acid is not particularly limited, and it may be added to the salt before polymerization, during polymerization, after polymerization or before molding (for example, coating on molding chips) or It may be added during molding (for example, mixing into the melt). However, addition to the salt before the polymerization or addition during the polymerization is preferable from the viewpoint that gelation during the polymerization is suppressed and a finer polyamide can be obtained. [Operation] Generally, gelation of polyhexamethylene adipamide is
It is said that it occurs when the amino group reacts to introduce a cross-linking point into the polymer and induces three-dimensionalization, and bishexamethylenetriamine is said to be the main cross-linking point. The mono- or dialkali salt of aminocarboxylic acid suppresses the formation of bishexamethylenetriamine, has a small polymerization inhibitory property, and does not cause polymer foaming. [Examples] Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these specific examples. In the examples, the “relative viscosity of formic acid” is the relative viscosity at 25 ° C. of a solution prepared by dissolving 90% formic acid at a polymer concentration of 8.4% by weight. Bishexamethylenetriamine (BHT) is a polymer 1
Hydrolysis of g with 47 wt% HBr 10 ml (in glass ampoule 15
After 0 ℃ x 24hr), extract with ether with Soxhlet (24h)
r) and then evaporated to dryness, and one-fifth thereof was trimethylsilylated with 2.5 ml of NO-bis (trimethylsilyl) acetamide and quantified by gas chromatography using p-terphenyl as an internal standard. Formic acid insoluble matter was prepared by charging 10g of polymer into an autoclave and heat-treating at 300 ° C for 26hrs, adding 1g of this heat-treated polymer to 100g of 90% formic acid, leaving it for 24hrs, filtering with a glass filter (11G1), and filtering residue 100 times. It was done. Example 1 A 50% aqueous solution of hexamethylenediaminemonium adipate was quantitatively supplied at a rate of 3000 parts / hr, concentrated to 70% in a concentration tank, and then maintained at 220 ° C. to 250 ° C. while maintaining a pressure of 17.5 kg / cm ^{2 in} a reactor. The temperature was raised to 1.5 ° C. in 1.5 hours. Then, it was flushed through a nozzle into cold water to obtain a low molecular weight oligomer having a relative viscosity of 13 formic acid. To 100 g of the oligomer, 0.8 mmol of a dicarboxylic acid or aminocarboxylic acid mono- or dialkali salt shown in Table 1 was added as alkali and heat treatment was performed at 300 ° C. for 26 hours. The results are shown in Table 1. As an alkali metal, Na, K, Rb and Cs are effective. Example 2 To 100 g of the oligomer obtained in Example 1, the adipic acid mono-K salt was added in an amount shown in Table 2 and heat-treated at 300 ° C. for 24 hours. The results are shown in Table 2. Adipic acid mono-K salt was added in an amount shown in Table 2 and heat treated at 300 ° C. for 26 hours. The results are shown in Table 2. The amount of alkali salt added may be 0.2 mmol or more, and the effect is almost saturated at 2.0 mmol or more. Comparative Example 1 To 100 g of the oligomer obtained in Example 1, the phosphorus compound shown in Table 3 was added at a phosphorus equivalent of 60 ppm and heat-treated at 300 ° C. for 26 hours. The results are shown in Table 3. Comparative Example 2 To 100 g of the oligomer obtained in Example 1, sodium hypophosphite was added in an amount shown in Table 4 and heat treated at 300 ° C. for 26 hours. The results are shown in Table 4. If the addition amount of the phosphorus compound is a small amount of 200 ppm or less, there is some effect, but if it is more than 200 ppm, the production amount of bishexamethylenetriamine is rather increased. Example 3 100,000 parts of a 50% aqueous solution of hexamethylene diammonium adipate, 160 parts of adipic acid mono-K salt, and 10 parts of sodium hypophosphite were charged into a polymerization tank, heated to 70% and concentrated to a pressure of 17.5 kg / cm ² . The temperature is raised by heating, and then the temperature is raised from 210 ° C to 280 ° C in 3 hours while maintaining 17.5 kg / cm ² . Then, the pressure was returned to normal pressure for 1 hr, and the polymer was discharged. The obtained polymer had a relative viscosity of formic acid of 51.3, and the formic acid-insoluble portion was 18.8 when heat-treated at 300 ° C. for 26 hours. 50,000 parts of the obtained chip were transferred to a tumbler type solid-state polymerization machine.
Polymerization was carried out at a jacket temperature of 10 ° C. and a nitrogen flow rate of 3 / hr / kg of polymer. The rate of increase in the relative viscosity of formic acid per unit time was 4.5. Comparative Example 3 The same experiment was conducted by using 50 parts of NaOH instead of the adipic acid mono-K salt of Example 3. The polymer obtained had a relative viscosity of formic acid of 45.0, and the formic acid-insoluble portion was 21.4 when heat-treated at 300 ° C. for 26 hours. The rate of increase in relative viscosity of formic acid during solid-state polymerization was 3.1. Comparative Example 4 Instead of the mono-K salt of adipic acid of Example 3, K-acetate salt of 85 was used.
The same experiment was performed using the parts. The polymer obtained had a relative viscosity of formic acid of 46.5, and the formic acid-insoluble portion was 19.4 when heat-treated at 300 ° C. for 26 hours. The rate of increase in relative viscosity of formic acid during solid-state polymerization was 3.5. Comparative Example 5 100,000 parts of a 50% aqueous solution of hexamethylene diammonium adipate was charged into a polymerization tank, heated and concentrated to 70%, and the pressure was raised to 17.5 kg / cm ² , and then the temperature was maintained at 17.5 kg / cm ^2. Increase from 210 ° C to 280 ° C in 3 hours. After that, the pressure was returned to normal pressure for 1 hr, and the polymer was discharged.
The obtained polymer has a relative viscosity of formic acid of 55.0.
The formic acid-insoluble part was 46.0 when heat-treated at 300 ° C for 24 hours. The rate of increase in the relative viscosity of formic acid during solid-state polymerization was 4.6.

Claims (1)

(57) [Claims] Polymerization was carried out by adding 0.2 mmol to 4 mmol of a dicarboxylic acid or aminocarboxylic acid mono- or dialkali salt (excluding Li) to 100 g of polyamide containing polyhexamethylene adipamide as a main component. A method for producing a characteristic polyamide. 2. The method for producing a polyamide according to claim 1, wherein the polymerization is carried out so that the amount of bishexamethylenetriamine produced is 35 mg / g of the polymer or less.