JPH0376756A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain a flame-retardant polyamide resin composition free from discoloration even when dried by heating and excellent in thermal stability, by mixing a specified polyamide resin with an inorganic compound and a flame retardant comprising a triazine compound. CONSTITUTION:A resin composition obtained by mixing 100 pts.wt. polyamide resin having a terminal amino group content of at least 9X10<-5>mol/g of the polymer with 1-20 pts.wt. flame retardant comprising a triazine compound and 0.001-5 pts.wt. inorganic phosphorus compound. In order to obtain a flame- retardant resin having the advantage of the flame retardant used, it is desirable that the polyamide resin and a finely divided flame retardant are mixed in a Henschel mixer, etc., and then internally mixed with an extruder, etc. As the inorganic phosphorus compound, especially alkaline earth metal salts of hypophosphorous acid, such as sodium hypophosphite, calcium hypophosphite, and barium hypophosphite, are preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polyamide resin composition. Specifically, the present invention relates to a polyamide resin composition that is flame retardant and has excellent heat-resistant stability without coloring even when heated and dried.

<Conventional technology> Polyamide resins are used in various fields such as automobile parts, electrical/electronic parts, and mechanical parts due to their good mechanical properties, moldability, and chemical resistance. There is a strong demand for flame retardancy in electrical and electronic component applications, and even polyamide resins, which are inherently self-extinguishing, need to be given even higher flame retardancy. A polyamide resin made by blending a triazine compound flame retardant with a polyamide resin is well known (Japanese Unexamined Patent Publication No. 53-31759,
53-125459). This polyamide resin is an extremely excellent resin composition with sufficient flame retardancy and no bleed-out or blooming.

<Problems to be Solved by the Invention> These flame-retardant polyamide resin compositions can also be used to reprint the molding shoulders of sprues, runners, etc. that are generated during molding, in order to improve the productization rate during molding and processing. Usually done. For reuse, sprues, runners, etc. are crushed in a crusher. Polyamide resin is hygroscopic and absorbs moisture from the air during the grinding process. If a polyamide resin that has absorbed moisture is used as it is for molding and processing, molding and processing properties will be significantly impaired due to foaming due to moisture. Therefore, usually 80
Drying is carried out at temperatures between 150°C and 150°C. Polyamide resins have the disadvantage of being highly colored when drying is carried out in a stream of air. Therefore, a difference in color tone occurs between a product in which molding/processing waste is reused and a product in which the molding/processing waste is not reused, resulting in a significant reduction in commercial value. Therefore, the present inventors investigated to obtain a flame-retardant polyamide resin composition that has excellent heat resistance and heat-resistant stability that does not become colored even under dry conditions in high-temperature air. proposed adding alkaline earth metal salts of hypophosphite.

Flame-retardant polyamide resin compositions to which phosphorus compounds have been added are already known. That is, in JP-A-54-94540, the addition of organic and inorganic phosphorus compounds was disclosed in JP-A-58-183.
No. 747 discloses the addition of an organic phosphorous acid compound, and JP-A-51-59946 discloses the addition of an alkali metal salt of hypophosphite. However, the purpose of the composition disclosed in the same publication is to improve the heat resistance of flame retardants, improve tensile elongation and impact resistance, or use flame retardant aids to improve flame retardancy. Therefore, after extensive study, the present inventors proposed adding an alkaline earth metal salt of hypophosphite to polyamide resin. . Addition of alkaline earth metal hypophosphite salt showed a remarkable effect on coloring, but as a result of further studies, the amino end group concentration was set at 6 x 10-' (mol/g-polymer). The present inventors have discovered that the effect of preventing coloring of the layer can be further developed by the above-mentioned method, and have arrived at the present invention.

<Means for Solving the Problems> In other words, the present invention provides a solution in which the amino terminal group concentration is 6 x 10-' (
mol/g-polymer> or more polyamide resin 100
The object of the present invention is to provide a polyamide resin composition containing (a) 1 to 20 parts by weight of a triazine compound flame retardant and (b) 0.001 to 5 parts by weight of an inorganic phosphorus compound.

The present invention will be explained in detail below.

The polyamide resin used in the present invention is a polyamide resin whose main constituents are an amino acid, a lactam or a diamine, and a dicarboxylic acid and whose amino end group concentration is 6×10 −′ (mol/g-polymer) or more. Specific examples of the components include lactams such as ε-caprolactam, enantlactam, and ω-laurolactam, amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid, tetramethylene diamine, hexamethylene diamine. , undecamethylene diamine, dodecamethylene diamine, 2.2.4-/2.4.4-trimethylhexamethylene diamine, 5-methylnonamethylene diamine, m-xylylene diamine, p-xylylene diamine, 1. 3-bisaminomethylcyclohexane,
1.4-Bisaminomethylcyclohexane, bis-p-
Diamines such as aminocyclohexylmethane, bis-p-aminocyclohexylpropane, isophoronediamine, adipic acid, superric acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid , terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, dimer acid, and other dicarboxylic acids. These components are subjected to polymerization either alone or in the form of a mixture of two or more, and both the polyamide homopolymer and copolymer thus obtained can be used in the present invention. Particularly useful polyamides in the present invention include polycabramide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene diamine (nylon 610), and polyundecane. amide (nylon 11), polydodecanamide (nylon 1)
2>, polyhexamethylene adipamide/hexamethylene terephthalamide copolymer (nylon 66/6T),
Polycabramide/polyhexamethylene adipamide copolymer (nylon 6/66) and mixtures of these polyamides.

There is no particular restriction on the degree of polymerization of the polyamide used here, and any polyamide having a relative viscosity of 1% concentrated sulfuric acid solution at 25° C. within the range of 1.5 to 5.0 can be used. In addition, the terminal group concentration of the polyamide resin was changed to 6X1.
The preparation to 0-'mol/g-polymer can be easily carried out by adding monoamine, diamine compounds and derivatives thereof.

Examples of monoamine and diamine compounds include methylamine, ethylamine, propylamine, isopropylamine, hexamethylenediamine, piperazine, N-aminopentylpiperazine, N,N-diaminopentylpiperazine, N-aminopropylmorpholine, tetramethylenediamine, and Decamethylene diamine, dodecamethylene diamine, 2,2.4-/2.4.4-trimethylhexamethylene diamine, 5-methylnonamethylene diamine, m-xylene diamine, p-xylene diamine, 1
．． 3-bisaminomethylcyclohexane, bis-p-aminocyclohexylpropane, isophoronediamine, stearylamine and derivatives thereof are used. The amine compound may be used alone or in combination of two or more types.The timing of adding these terminal group concentration regulators is before polymerization,
It may be added at any stage during or after polymerization.

Especially when added together with an inorganic phosphorus compound before polymerization,
The effect is that the polymerization rate can be controlled more easily than when an inorganic phosphorus compound is used alone.

The triazine compound flame retardant used in the present invention is represented by the general formula % (in the formula, R is a hydrogen atom or an alkyl group, and each R may be different from each other). Compounds and melamines, melamine/cyanuric acid, for example, compounds represented by the general formula (I) include cyanuric acid, trimethyl cyanurate, triethyl cyanurate, tri(n-propyl) cyanurate, methyl cyanurate, Examples include diethyl cyanurate.

Examples of the compound represented by the general formula (n) include isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, tri(n-propyl) isocyanurate,
Examples include diethyl isocyanurate and methyl isocyanurate.

Specific examples of melamines include melamine, ammelide, ammeline, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, melem, melon, and the like.

Melamine/cyanuric acid (hereinafter referred to as MC salt) is an equimolar reaction product of melamine and cyanuric acid.
It is obtained by reacting with stirring at °C and filtering the produced precipitate. This is a white solid and is preferably used after being ground into a fine powder. Further, some of the amino groups and hydroxyl groups in the MC salt may be substituted with other substituents.

Among these triazine compound flame retardants, cyanuric acid, isocyanuric acid, melamine, and MC salts are preferably used,
In particular, MC salts are preferably used, and the triazine compound flame retardants may be used alone or in combination of two or more.

The amount of these triazine compound flame retardants used is usually 1 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, per 100 parts by weight of the polyamide resin. When the amount used is less than 1 part by weight, there is no flame retardant effect, and even when the amount used is more than 20 parts by weight, the flame retardance obtained will not be further improved.

Any known technique can be applied to blend the triazine-based compound flame retardant into the polyamide resin, but in order to obtain a flame-retardant resin that takes advantage of the advantages of the flame retardant used in the present invention, it is necessary to blend the triazine compound flame retardant into the polyamide resin and the polyamide resin. It is preferable to mix the mixture with a flame retardant using a Henschel mixer or the like, and then internally mix the mixture using an extruder or the like.

Examples of the inorganic phosphorus compounds used in the present invention include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, etc., and alkaline earth metal salts thereof. Examples of the alkaline earth metals include potassium, calcium, strontium,
Cesium, sodium, barium, beryllium, magnesium, lithium, rubidium, zinc, aluminum,
Examples include gallium, indium, thallium, germanium, antimony, bismuth, boronium, and lead. Preferably, hypophosphorous acid and alkaline earth metal salts of hypophosphorous acid are used. Particularly preferred are sodium hypophosphite, manganese hypophosphite, calcium hypophosphite, magnesium hypophosphite, potassium hypophosphite, barium hypophosphite, strontium hypophosphite, zinc hypophosphite, Alkaline earth metal salts of hypophosphite such as cobalt phosphite and lead hypophosphite are used.

The amount of these inorganic phosphorus compounds added is 100% of the polyamide resin.
The amount is usually 0.001 to 5 parts by weight, particularly preferably 0.01 to 3 parts by weight. Addition amount is 0.
If the amount is less than 0.001 parts by weight, the heat resistance stability of the polyamide resin will be significantly reduced, and it will become colored under heating and drying conditions in an air atmosphere. Even if the amount added is more than 5 parts by weight, the heat resistance stability of the resulting polyamide resin will not be further improved.

The timing of adding the inorganic phosphorus compound is not particularly limited, and it can be added at any stage before, during, or after polymerization. Further, the inorganic phosphorus compounds may be used alone or in combination of two or more.

The polyamide resin composition of the present invention may be used as a polyamide resin composition master of a polyamide resin and an inorganic phosphorus compound, or as a polyamide resin composition master of a polyamide resin, a triazine compound flame retardant, and an inorganic phosphorus compound. are also possible and are included in the preferred embodiments of the invention.

Other additives such as lubricants, antistatic agents, weather resistant agents, heat resistant agents, reinforcing agents, etc. may be added to the polyamide resin composition of the present invention in appropriate amounts at any stage to the extent that the effects of the present invention are not significantly impaired. be able to.

<Examples> Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples.

In Examples and Comparative Examples, all "parts" indicate "parts by weight".
The "color tone rYI value" is a value indicating the degree of yellow coloration measured by SM-Color Computer: 5M-3 manufactured by Suga Test Instruments Co., Ltd., and the larger the value, the more yellow the color is.

Comparative Example 1 1,900 g of hexamethylenediamine adipate and 630 g of water were placed in a polymerization pot, the atmosphere was replaced with nitrogen, and the polymerization was carried out according to the usual polymerization method.The strands were spun from the polymerization pot and cut with a cutter to form a pellet-like polyurethane. An amide resin was obtained. This pellet was vacuum dried at 80-100°C for 16 hours. Parts by weight of MCC salt type were added to 100 parts by weight of the dried pellets and mixed in a Henschel mixer. This mixture was melt-kneaded in a PCM30 twin-screw extruder manufactured by Ikegai Co., Ltd. The strands were cooled and then pelletized in a pelletizer to form a polyamide resin. A composition was obtained.The pellet obtained here was heated to 80°C.
Dry at ~100°C under vacuum for 16 hours. The dried pellets were placed in a Petri dish, placed in a gear oven (manufactured by Tabai MFG Co., Ltd.) controlled at 140° C., and taken out at 30 and 60 minutes to measure the YI value, assuming drying conditions for recycling. The results are shown in Table 1.

Comparative Example 2 1900 g of hexamethylenediamine adipate, 630 g of water, and 0.57 g of manganese hypophosphite were placed in a polymerization pot, and the atmosphere was replaced with nitrogen. Polymerization was carried out according to the usual polymerization method, and the same procedure as in Comparative Example 1 was carried out. The heat resistance stability was evaluated and the results shown in Table 1 were obtained.

Comparative Example 3 A composition containing 1,900 g of hexamethylene diamine adipate, 630 g of water, 0.57 g of manganese hypophosphite, and benzoic acid as an end group concentration regulator at a ratio of 6/1000 mol to hexamethylene diamine adipate. The procedure and evaluation were performed in the same manner as in Comparative Example 1, except that the polymer was placed in a polymerization pot and polymerized, and the results shown in Table 1 were obtained.

Example 1 Composition of 1900 g of hexamethylene diamine adipate, 630 g of water, 0.57 g of manganese hypophosphite, and 6/1000 mole of hexamethylene diamine as an end group concentration regulator based on hexamethylene diamine adipate. The same procedure as in Comparative Example 1 was performed except that the sample was placed in a polymerization pot and polymerized, and the results shown in Table 1 were obtained. The YI value was significantly improved compared to Comparative Examples 1 to 3.

Comparative Example 4 The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that a composition of 1900 g of hexamethylenediamine adipate, 630 g of water, and 0.53 g of sodium hypophosphite was placed in a polymerization pot and polymerized. The results shown in Table 1 were obtained.

Comparative Example 5 A composition containing 1900 g of hexamethylene diamine adipate, 630 g of water, 6/1000 mol of benzoic acid as an end group concentration regulator based on hexamethylene diamine adipate, and 0.53 g of sodium hypophosphite was prepared. The heat resistance stability was evaluated in the same manner as in Comparative Example 1 except that it was placed in a polymerization pot and polymerized, and the results shown in Table 1 were obtained.

Comparative Example 6 A composition containing 1900 g of hexamethylenediamine adipate, 630 g of water, 0.53 g of sodium hypophosphite, and benzoic acid as an end group concentration regulator at a ratio of 6/1000 mole to hexamethylene diamine adipate. The procedure and evaluation were performed in the same manner as in Comparative Example 1, except that the polymer was placed in a polymerization pot and polymerized, and the results shown in Table 1 were obtained.

Example 2 Composition of 1900 g of hexamethylene diamine adipate, 630 g of water, 0.53 g of sodium hypophosphite, and 6/1000 mole of hexamethylene diamine as an end group concentration regulator based on hexamethylene diamine adipate. The same procedure as in Comparative Example 1 was performed except that the sample was placed in a polymerization pot and polymerized, and the results shown in Table 1 were obtained. The YI value was significantly improved compared to Comparative Examples 4 to 6.

Example 3 Composition of 1900 g of hexamethylene diamine adipate, 630 g of water, 1.62 g of sodium hypophosphite, and 6/1000 mole of hexamethylene diamine as an end group concentration regulator based on hexamethylene diamine adipate. The evaluation was carried out in the same manner as in Comparative Example 1, except that 0 was added to the polymerization pot and polymerized, and the results shown in Table 1 were obtained. The heat resistance stability was maintained by increasing the amount of sodium hypophosphite added. Compared to Comparative Example 6, the YI value is significantly lower.

Comparative Examples 7 to 10 The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that the alkaline earth metal salt of hypophosphite in Table 2 was used in place of the manganese hypophosphite in Comparative Example 2 for polymerization. The results shown in Table 2 were obtained.

Examples 4 to 7 The procedure was the same as in Comparative Example 1, except that during the polymerization in Comparative Example 1, the alkaline earth metal salt of hypophosphite and the end group concentration regulator listed in Table 2 were added and the polymerization was carried out in the polymerization pot. The heat resistance stability was evaluated, and the results shown in Table 2 were obtained. In all cases, the YI value decreased significantly and the heat resistance stability improved.

Comparative Examples 11 to 14 The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that the inorganic phosphorus compounds listed in Table 3 were added during the polymerization of Comparative Example ①, and the inorganic phosphorus compounds listed in Table 3 were placed in the polymerization pot and polymerized. The following results were obtained.

Examples 8 to 11 The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that the inorganic phosphorus compound and end group concentration regulator listed in Table 3 were added during the polymerization of Comparative Examples 11 to 14. The results shown in Table 3 were obtained. It can be seen that both have a smaller YI value than the comparative example and are superior in heat resistance stability.

Comparative Examples 15 to 22 Heat-resistant stability was determined in the same manner as in Comparative Example 1, except that during the polymerization in Comparative Example 1, the organic phosphorus compound and end group concentration regulator listed in Table 4 were added and the polymerization was carried out in the polymerization pot. Evaluate and Table 4
The results shown are obtained.

None of them showed a YI value superior to that of inorganic phosphorus compounds.

442- Comparative Examples 23 to 27 The type of polyamide was nylon 6/66 and nylon 6.
The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that a composition of an end capping agent and sodium hypophosphite shown in Table 5 was prepared and polymerized using No. 10, and the results shown in Table 5 were obtained.

Examples 12 to 14 The type of polyamide was nylon 6/66 and nylon 6.
The heat resistance stability was evaluated in the same manner as in Comparative Example 1, except that a composition of an end capping agent and sodium hypophosphite shown in Table 5 was prepared and polymerized using No. 10, and the results shown in Table 5 were obtained. In both cases, it can be seen that the composition using hexamethylene diamine as the terminal group concentration regulator has a smaller YI value and is superior in heat resistance stability.

Examples 15 to 16 The polyamide resin compositions of the examples shown in the master polymer column of Table 6 and the inorganic phosphorus compound were used as master polymers, and the polyamide resins shown in the polyamide resin type column (for dilution) were used as master polymers. Polymer> and MC
Salt was mixed in a Henschel mixer in the proportions shown in Table 6, this mixture was melt-kneaded in a PCM30 twin-screw extruder manufactured by Ikegai Co., Ltd., and the strands were cooled and pelletized in a pelletizer.The pellets obtained here are compared below. The evaluation was carried out in the same manner as in Example 1, and the results shown in Table 6 were obtained. In all cases, polyamide resin compositions with small YI values and good heat resistance stability were obtained.

444- <Effect of the invention> As in the present invention, when the amino terminal group concentration is 6 x 10-5 mol/
A polyamide resin composition consisting of a polyamide resin having a polymer content of 6x10-' mole/g-
The heat resistance stability is further improved compared to the case of polyamide resin compositions using polyamide resins smaller than the polymer, and the effect of suppressing discoloration of recycled polyamide resin compositions is remarkable, especially when drying at high temperatures in an air atmosphere. It has now become possible to obtain a polyamide resin composition.

Patent application Daitoshi Co., Ltd.

Claims (2)

[Claims] (1) Amino end group concentration is 6 x 10^-^5 (mol/g
-Polymer) A polyamide resin composition containing (a) 1 to 20 parts by weight of a triazine compound flame retardant and (b) 0.001 to 5 parts by weight of an inorganic phosphorus compound, based on 100 parts by weight of the polyamide resin. thing. (2) The polyamide resin composition according to claim 1, wherein the inorganic phosphorus compound is an alkaline earth metal salt of hypophosphorous acid.