KR970004669B1 - Polyamide resin composition - Google Patents

Abstract

The composition of polyamide resin is prepared by containing 3-20wt% of cyanuricmelamine, 0.1-5wt% of biscaprolactam compound indicated as general formula(A) and 0.05-2wt% of sodiumbenzenphosphinate based on the 100wt% of polyamide resin. The prepared polyamide resin composition has an extraordinary fire retardation, thermal stability and mechanical physical character. In the formula, R means -CH-, -CH2CH2- or the like.

Description

Polyamide Resin Composition

The present invention relates to a polyamide resin composition, and more particularly to a polyamide resin composition excellent in flame retardancy.

Polyamide resins are rapidly increasing in demand in the electrical and electronic fields, construction materials, and automobile parts. In addition, as the regulations on special requirements and stability are strengthened, flame retardation of polyamide resins is urgently required.

As a method of imparting flame retardancy to polyamide resins, a method of mainly adding a flame retardant is widely used. Flame retardants include organic compounds containing halogen, halogen compounds, nitrogen compounds, inorganic compounds and the like. However, in order to secure effective flame retardancy in the known flame retardant-containing polyamide resin composition, a large amount of flame retardant must be used, and as a result, the chemical and physical properties required for the polyamide resin may occur. Therefore, it is important to consider the effects on workability, dispersibility, discolorability, toxicity, processability, thermal stability, and mechanical strength when selecting a flame retardant.

Conventionally, a method of imparting a flame retardant to a polyamide resin is a method of using a halogen compound such as a halogenated diphenyl oxide and a metal oxide as a flame retardant (US Patent Nos. 4,016,139 and 3,864,302, and Japanese Patent Publication No. 77-85252). However, when using halogen-containing compounds and metal oxides as flame retardants, an excessive flame retardant should be used to give sufficient flame retardancy to polyamide, resulting in deterioration of mechanical properties and poor workability. The problem of the generation of toxic gases during processing or combustion has been pointed out.

In addition, a method using a nitrogen-based melamine as a flame retardant (US Patent No. 3,660,344, Japanese Patent Publication No. 76-54655) is known, in this case, melamine sublimes during processing at high temperatures (270-280 ℃) Therefore, there is a problem of contaminating the surface of the mold and the molded article, and a problem that melamine is molded in the surface of the molded article over a long time has been pointed out.

In addition, a method of using cyanuric acid as a flame retardant is known (UK Patent No. 1,484,151, US Patent No. 3,980,616), but in this case, cyanuric acid is unstable in heat, which causes bubbles in the molded product during injection molding and silver on the surface of the injection molded product. There is a problem that the phenomenon caused by the surface defects and the reduction of the strength of the molded article.

In addition, there is a known method of using melamine cyanurate as a flame retardant (Japanese Patent Laid-Open Nos. 80-21062, 79-40855, and 87-195043), and this method uses melamine or cyanuric acid as described above. Although it is somewhat improved compared to the case used, melamine cyanuric acid also has a low thermal stability and causes foaming on the surface of the injection molded product when processing a resin requiring a high processing temperature. In particular, the flame retardant effect is reduced due to poor dispersibility. There is a problem.

Accordingly, the present inventors have conducted extensive research to solve the problems in the prior art as mentioned above, and as a result, specific biscaprolactam compounds and sodium benzene phosphinates in polyamide resin compositions containing melamine cyanurate as a flame retardant By further containing it, it maintains excellent flame retardancy, thermal stability and mechanical stiffness, and does not interfere with processing due to its excellent compatibility with resin. It has been found that a polyamide resin composition can be obtained which does not occur and has advantages such as excellent fluidity.

Therefore, the polyamide resin composition provided by the present invention is 3-20 parts by weight of melamine cyanurate based on 100 parts by weight of polyamide resin, 0.1-5 parts by weight of biscaprolactam compound represented by the following general formula (A), sodium It is characterized by containing 0.05-2 parts by weight of benzenephosphinate.

[Wherein R is- -,- - or Represents a group]

The biscaprolactam compound (A) applied to the composition not only lowers the melt viscosity of the resin during processing, but also improves the dispersibility in the polyamide resin of melamine cyanurate, which is a flame retardant, as well as moisture (hydroxyl group) possessed by melamine cyanurate By reacting with, it has the advantage of minimizing the influence of water during processing, and sodium benzene phosphinate acts as processing heat and nucleating agent to suppress decomposition during product molding and shorten the molding cycle. It improves the workability at the time of forming the final product from the composition of the composition and also increases the surface gloss of the molded article.

Resin modified by this invention is a polyamide resin, Especially nylon 6, nylon 66, nylon 6/66 copolymer, etc. are suitable.

In the composition of the present invention, the blending amount of melamine cyanurate is preferably 3-20 parts by weight, more preferably 5-15 parts by weight based on 100 parts by weight of the polyamide resin. The desired flame retardancy cannot be expected in melamine cyanurate of less than 3 parts by weight, and unfavorable at lower than 20 parts by weight of mechanical properties and deterioration in dispersibility. Moreover, the compounding quantity of a biscaprolactam compound is 0.1-5 weight part with respect to 100 weight part of polyamide resins, More preferably, it is 0.5-2 weight part. If it is less than 0.1 part by weight, effective dispersibility and processing stability cannot be expected, and if it exceeds 5 parts by weight, there is a disadvantage in that mechanical properties are lowered due to a sharp drop in melt viscosity, which is not preferable. In addition, the compounding quantity of sodium benzene phosphinate is suitable for 0.05-2 weight part with respect to 100 weight part of polyamide resins, More preferably, 0.2-1 weight part is suitable. If it is less than 0.05 parts by weight, no effect can be expected. If it is more than 2 parts by weight, it is not preferable because there is no economical advantage as well as a decrease in mechanical properties.

In addition to the above components, the composition of the present invention may contain additives well known in the art, and examples of such additives include a releasing agent, a pigment, a weathering agent, an impact agent, and the like.

It is preferable to use the method of melt-kneading a molding polyamide chip and an additive in the kneading extruder for kneading of this composition. At this time, it is preferable that the cyanuric acid melamine and the biscaprolactam as the flame retardant are blended in advance and simultaneously introduced into the feedstock feeder.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1-4

As shown in Table 1 below, various compositions were prepared according to the change in content of each component of the composition of the present invention. The resin used was 98% sulfuric acid solution, nylon 6 having a relative viscosity of 2.4, and dried at 85 ° C. in a dehumidifying dryer for 6 hours or more, and the melamine cyanurate, biscaprolactam compound, and sodium benzene phosphinate were heated to 250 ° C. It was melt-kneaded in a twin screw extruder to prepare chips. The chip was then dried and a screw-type extruder heated to a barrel temperature of 240-250 ° C. produced a bell-shaped specimen, a bar specimen and a disc specimen.

Comparative Example 1-4

According to the composition of Table 1, a specimen of the comparative composition was prepared in the same manner as in the above example.

* 0.3% EBS (ethylene bis stearamide) is applied to the whole composition

Example 5-8

As shown in Table 2 below, a chip was prepared in the same manner as in Example 1-4 with respect to nylon 66 resin having a relative viscosity of 2.6 in a 98% sulfuric acid solution. At this time, the processing temperature of resin was 270-280 degreeC.

Comparative Example 5-8

According to the composition of Table 2, the specimen of the comparative composition was prepared in the same manner as in Example 5-8.

* 0.3% EBS (ethylene bis stearamide) is applied as a release agent

evaluation

The flame retardancy, blooming or not, and mechanical properties of the sample bell-shaped, bar-shaped, and disc-shaped specimens of the polyamide resins prepared in Examples 1-8 and Comparative Examples 1-8 were evaluated.

Flame retardancy was tested on 3.2mm, 1.6mm, and 0.8mm thickness specimens according to the combustion test method specified in UL 94 standard, and whether or not precipitation of flame retardant in the mold (mold deposit) was visually observed inside the mold. It was judged whether it occurred or not, and whether it was blooming or not was made by making a disc specimen of 3.2mm thickness and 100mm diameter and heat-treating it at 150 ℃ hot air dryer for 10 hours and visually observing the surface state of the specimen. Injection molded specimens were evaluated according to ASTM specifications. In addition, the fluidity of the resin was evaluated as a melt prolate.

As shown in the results of Table 3, it can be seen that the polyamide composition of the present invention is excellent in flame retardancy, thermal stability, mechanical rigidity and compatibility with the resin.

* Liquidity evaluation: 1) Nylon 66; Evaluated under 270 ℃ × 2160g load

2: nylon 6; Evaluated under 245 ℃ × 2160g load

* Presence of flame retardant: Precipitation exists (○), no precipitation (×)

* Blooming: Blooming (○), Blooming (×)

* Flame Retardant Indication (UL 94 Standard)

As described above, according to the present invention, the biscaprolactam compound added to the polyamide resin composition improves dispersibility in the molten resin of melamine cyanurate, which is a flame retardant, and decomposes the resin by reaction with the hydroxyl group of melamine cyanurate. It is suppressed and the fluidity | liquidity of a molten resin is improved and the molded article which has a beautiful surface is provided. In addition, the composition imparts excellent flame retardant properties corresponding to V0 in the UL 94 vertical combustion test, even for molded articles of thin thickness. The composition of the present invention having such characteristics is suitable for applications in electric and electronic fields and automobile parts requiring flame retardancy, molding processability, and excellent mechanical properties.

Claims (2)

In the polyamide resin composition, 3-20 parts by weight of melamine cyanurate and 0.1-5 parts by weight of biscaprolactam compound represented by the following formula (A) and sodium benzene phosphinate relative to 100 parts by weight of polyamide: A polyamide resin composition comprising a weight part. [Wherein R is- -,- - or Represents a group] The polyamide resin composition according to claim 1, wherein the polyamide resin is selected from nylon 6, nylon 66, and nylon 6/66 copolymer.