JPH0551531A - Polyamide composition - Google Patents

Abstract

PURPOSE:To provide a polyamide composition remarkably improved in the effect of preventing the gelation of polymethyleneadipamide during polymeriza tion and molding. CONSTITUTION:A polyamide composition which consists of polymethyleneadipamide (a) and a compound (b) of general formula MHSO3 (wherein M is an alkali metal) or general formula M<3>(HSO3)2 (wherein M is an alkaline earth metal). The additive (b) for preventing gelation exhibits a remarkable effect of preventing the gelation of the polymethyleneadipamide (a) and causes very little foaming of the polymer. The additive, when added before or during polymerization, can prevent the gelation during polymerization and has no adverse effect such as the inhibition of polymerization, so that finer polyamide can be obtained. When added before molding, it causes neither the foaming of an obtained molding due to gelation nor the breakage of fiber, so that it does not reduce the yield of a polyamide product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide composition in which the gelation-preventing effect of polymethylene adipamide at the polymerization stage and molding is remarkably improved.

[0002]

2. Description of the Related Art Polyamides containing dicarboxylic acid as one reaction component, such as polyhexamethylene adipamide, have poor thermal stability. Polyamide tends to form a gel, and this gel causes various problems such as a decrease in heat transfer in the polymerization step, an increase in thread breakage in the spinning step, and the generation of black foreign matter in the polymer.

Various methods for preventing this gelation have been investigated, but the method of adding a phosphorus compound or an alkali metal compound is the main one. Japanese Patent Publication 45-11
In 836, pyrophosphite is disclosed in Japanese Examined Patent Publication No. 45-356.
No. 67 discloses an amide compound of an organic phosphinic acid, and Japanese Patent Publication No. 45-12986 discloses a mono- or diester magnesium salt of phosphorous acid.
No. 351 discloses barium salts of mono- or diesters of phosphorous acid and orthophosphoric acid.
The publications disclose mono- or diester copper salts of orthophosphoric acid, respectively.

Further, in JP-B-51-24297, it is disclosed that a polyamide is blended with a phosphinic acid compound, a phosphonous acid compound and an alkali compound selected from alkali hydroxide and alkyl alcoholate.
No. 25065 discloses a polyamide containing a phosphinic acid compound, a phosphonous acid compound, a phosphonic acid compound, a phosphorous acid compound and an alkali hydroxide, an alkyl alcoholate, an alkylphenolate, an alkali carbonate and a dicarboxylic acid anhydride,
Alternatively, the addition of these hydrolysates should
In JP-A 1-265066, a phosphinic acid compound, a phosphonic acid compound, a phosphorous acid compound and an alkali hydroxide, an alkyl alcoholate, an alkyl phenolate, polyamide,
Blending an alkali compound selected from alkali carbonates with α-phenylenediamine-induced resistance is disclosed in JP-B-51-
Japanese Patent No. 41906 discloses that a polyamide is blended with a phosphonic acid compound, a phosphorous acid compound and an alkaline compound selected from an alkali hydroxide and an alkyl alcoholate.

Further, Japanese Patent Laid-Open No. 104654/1989 discloses the addition of a dicarboxylic acid excluding Li or a mono- or dialkali salt of an aminocarboxylic acid as an alkaline component. Japanese Unexamined Patent Publication (Kokai) No. 1-104652 discloses a method of adding an alkaline salt excluding Li of an inorganic acid having an acid dissociation index PKa of 3 or more excluding carbonic acid and hydrogen fluoride as an alkaline component. JP-A-1-104
Japanese Patent No. 653 discloses a method of adding an alkali fluoride excluding LiF.

[0006]

However, although the phosphorus compounds have an effect of preventing gelation, they have a small effect, and when they are added in an increased amount, they also promote gelation. Addition of a large amount of alkali hydroxide or a weak acid salt of alkali hinders the polymerization reaction if it is added in a large amount in order to enhance the prevention effect.

Gelation causes the generation of black foreign matter or foaming, and causes thread breakage in the case of the spinning process. Thus, gelling results in a large loss of yield in polyamide products. In order to solve such a problem, the present invention provides a technique that strongly prevents gelation and has no adverse side effects such as inhibition of polymerization.

[0008]

The present inventors have arrived at the present invention as a result of extensive studies on a polyamide composition having a sufficient gelation-inhibiting effect and having a polymer having a small foaming property. That is, the present invention provides (a) polymethylene adipamide and (b) general formula [I]:

Embedded image MHSO ₃ ... [I] (M is an alkali metal) or the general formula [II]:

Embedded image A polyamide composition comprising a compound represented by M ³ (HSO ₃ ) ₂ ... [II] (M is an alkaline earth metal).

The polypolymethylene adipamide (a) used herein uses adipic acid as the acid component and polymethylene diamine such as tetramethylene diamine, hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, etc. as the diamine component. It is also possible to use a modified polypolymethylene adipamide which is a prepared polyamide and which is added with 20% by weight or less of other amide-forming units.

Examples of such a small amount of amide-forming unit include aliphatic dicarboxylic acids such as sebacic acid and dodecanoic acid;
Aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid,
And aliphatic diamines such as polymethylenediamine; aromatic diamines such as metaxylenediamine; ω-aminocarboxylic acids such as ε-aminocaproic acid; lactams such as caprolactam and laurinlactam.

It is also possible to use a mixture of the above polypolymethylene adipamide (a) with 20% by weight or less of another polyamide. Further, the polypolymethylene adipamide (a) is an additive usually used for polyamides, for example, a heat stabilizer such as copper acetate, copper chloride, copper iodide, mercapto benzimidazole; manganese lactate, hypophosphorous acid. A light stabilizer such as manganese; a matting agent such as titanium dioxide or kaolin; a lubricant such as ethylenebisstearylamide or stearate; and a plasticizer may be included.

Typical examples of the gelation inhibitor additive (b) of the present invention include potassium sulfite and sodium hydrogen sulfite.

The additive (b) of the present invention may be added not only before the polymerization but also during the polymerization, after the polymerization, or at any time before or during the molding, but before the polymerization or during the polymerization. Gelation at the time is suppressed, and there are no bad side effects such as inhibition of polymerization,
A finer polyamide can be obtained. In addition, when added during molding, there is no fear of foaming due to gelation of the obtained molded product, occurrence of yarn breakage, and reduction of yield in polyamide products.

The amount of the additive (b) of the present invention to be added is based on the polyamide containing polymethylene adipamide as a main component.
0.05 mmol or more based on 1 g of the polyamide,
It is desirable to add 3.0 mmol or less. If the blending amount is less than 0.05 mmol, the gel preventing effect is small,
If the amount exceeds 3.0 millimoles, not only the gelation prevention is saturated, but also the mechanical properties are deteriorated.

[0015]

In general, gelation of polypolyhexamethylene adipamide is said to occur when the amino groups constituting the polyamide react to introduce cross-linking points into the polymer to induce three-dimensionalization. There is.

Bishexamethylenetriamine (hereinafter abbreviated as BHT) is said to be the main cross-linking point in the three-dimensionalization, but according to the gelation-preventing additive (b) of the present invention, the formation of BHT is prevented. It has an excellent effect that it suppresses very strongly and no polymer foaming is observed.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited by these examples. In this example, the effect of preventing gelation was represented by the amount of bishexamethylenetriamine (BHT) as a by-product.

The amount of bishexamethylenetriamine was determined by hydrolyzing 40 mg of the polymer with 4 ml of 47 wt% HBr0, heat-treating in a glass ampoule at 150 ° C. for 4 hours, and evaporating to dryness to obtain N-bis (trimethylsilyl).
After trimethylsilylation with 1.0 ml of acetamide, N
-Trifluoroacetylated with 1.0 ml of methylbistrifluoroacetamide, and quantified by gas chromatography using p-terphenyl as an internal standard. The relative viscosity of formic acid is 90% formic acid and the polymer concentration is 8.
It is the relative viscosity at 25 ° C. of a solution dissolved to 4% by weight.

[0019]

Example 1 A 50% aqueous solution of hexamethylene diammonium adipate was heated to a pressure of 17.5 kg / cm ^2.
Then, the temperature is raised from 250 ° C. to 290 ° C. while maintaining 17.5 kg / cm ² . Then, the pressure was returned to normal pressure in 0.5 hours, and the polymer was discharged. The polymer obtained had a relative viscosity of formic acid of 40.

[0020]

Example 2 To 6 g of the polymer obtained in Example 1,
12 mmol of the additives shown in Table 1 were added, and heat treatment was performed at 300 ° C. for 5 hours. BHT in the obtained polymer
The amounts are shown in Table 1.

[0021]

[Table 1]

[0022]

Example 3 To 6 g of the polymer obtained in Example 1, 12 mmol of the additive shown in Table 2 was added to obtain 300 g.
Heat treatment was performed at 8 ° C. for 8 hours. B in the obtained polymer
The amount of HT is shown in Table 2.

[0023]

[Table 2]

[0024]

[Comparative Example 1] To 6 g of the polymer obtained in Example 1, 12 mmol of sodium hydroxide was added, and the mixture was heated to 300 ° C.
Heat treatment was performed for 5 hours and 8 hours. Table 3 shows the amount of BHT in the obtained polymer. Compared with sodium hydroxide, the additive of the present invention has an extremely large gelation suppressing effect.

[0025]

[Table 3]

[0026]

Example 3 To 6 g of the polymer obtained in Example 1, reagents represented by potassium bisulfite and sodium bisulfite were added in the amounts shown in Table 4 and heat-treated at 300 ° C. for 8 hours. The results are shown in Table 4. Polymer 6g
At 0.06 millimoles per unit, a remarkable gelation suppressing effect is observed. Further, the effect is almost saturated even if 12 mmol is added.

[0027]

[Table 4]

[0028]

As described above, according to the specific antigelling additive (b) of the present invention, polymethylene adipamide (a) is used.
Has a remarkable gelation-inhibiting effect, and the foaming of the polymer is very small. Further, the gelation-preventing additive of the present invention, before polymerization, by addition during polymerization, gelation during polymerization is suppressed,
Moreover, finer polyamide can be obtained without adverse side effects such as inhibition of polymerization. In addition, addition during molding does not cause foaming or yarn breakage due to gelation of the obtained molded product, and does not reduce the yield of polyamide products.

Claims (1)

[Claims] 1. (a) Polymethylene adipamide and (b)
General formula [I]: [Chemical formula 1] MHSO ₃ ... [I] (M is an alkali metal), or general formula [II]: [Chemical formula 2] M ³ (HSO ₃ ) ₂ ... [II] ] (M is an alkaline-earth metal) It consists of a compound shown by these, The polyamide composition characterized by the above-mentioned.