JPS608055B2 - Flame retardant polyamide resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a polyamide resin composition.

Specifically, the present invention relates to a polyamide resin composition that has excellent properties during molding, is free from the precipitate phenomenon, and has excellent flame retardancy. In general, polyamide resins are characterized by their chemical properties,
It is a widely used material with excellent mechanical and electrical properties, wear resistance, oil resistance, chemical resistance, arc resistance, processability, etc., so it is suitable for plastic molded products, adhesives, etc. Although it is one of the important materials in the field,
With the application of UL standards to plastic materials, a high degree of flame retardancy has become required.

Polyamide resin originally has properties close to self-extinguishing,
Due to its many advantages in flammability, it is used in electrical equipment, etc., but it is not satisfactory, and it is difficult to impart a high degree of flame retardancy without impairing the above-mentioned properties of polyamide resin. Various attempts have been made in the past.

There are various methods for improving the flame retardancy of polymer compounds, and currently the most common method is to add various flame retardants to many materials including polyamide resins.

There are a wide variety of flame retardants that can be added to polyamide resin to impart flame retardancy to the resin. The polyamide resin must have good processability and thermal stability, and be highly effective in imparting flame retardancy without impairing the original properties of polyamide resin. , melamine, melamine cyanurate, etc., and there are many examples in which second and third compounds are added, but these have many drawbacks and cannot be said to be sufficient.

Further, as other flame retardant imparting agents, polysemicarbazide, polyacyl semicarbazide, polyurea, etc. are known, but their flame retardant imparting effect and heat resistance are not yet satisfactory.

The present invention has been made in view of the above points, and its purpose is to provide a polyamide resin composition that allows molded products with excellent heat resistance, flame retardance, and mechanical strength to be obtained even under extreme conditions. It's about doing. That is, the present invention is based on the general formula (wherein R represents an aliphatic, aromatic, or alicyclic hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 1 to 15).

) A flame-retardant polyamide resin composition obtained by blending an additive shown in the following formula into a polyamide resin. ”. The additive (represented by the above general formula) in the present invention is obtained by reacting melamiso and diisocyanate, and the diisocyanate used as a raw material includes ethylene diisocyanate, hexamethylene diisocyanate, and decamethylene diisocyanate. Aliphatic hydrocarbon diisocyanates such as polymethylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, dianisidine diisocyanate, 4,4'
-Diphenylmethane diisocyanate, 3,3-dimethyl-4,4'-diphenyl diisocyanate, aromatic hydrocarbon diisocyanate such as xylene diisocyanate, alicyclic diisocyanate such as cyclohexyl diisocyanate, isophorone diisocyanate, etc. Examples include group hydrocarbon diisocyanates.

Here, n in the general formula is an integer from 1 to 15, and originally any n value can be used, but in practice, the one that can be synthesized most easily is the one where n = 1, and n is an integer of 1 to 15. As the size increases, synthesis becomes more difficult, so those with n: 15 or more are subject to synthesis constraints. Therefore, n is particularly practical for synthesis.
= about 1 to 5. The additive in the present invention is
It has good compatibility with polyamide resins, can be easily mixed, and provides a uniform polyamide resin composition, so compared to conventional additives, it does not impair the properties of molded products made of polyamide resin compositions. The phenomenon of lead-out can also be prevented.

The additive in the present invention (represented by the general formula above) has good thermal stability because it contains a 1,3,5,1s-triazine ring in its molecule, and greatly contributes to improving the thermal stability of polyamide resin. .

Furthermore, the combined use of various additives, such as pigments and fillers, which are usually added to polyamide resins, may be used in combination to the extent that they do not impair the properties of the polyamide resin composition, and there is no restriction thereto.

The additive (represented by the above general formula) and polyamide resin in the present invention can be blended in a wide range of proportions, but usually in a polyamide resin.
Preferably 1 part by weight of the additive per 10 parts by weight of the amide resin
~10 parts by weight, more preferably 5 to 4 parts by weight.

The raw materials for synthesizing the additive (represented by the above general formula) used in the present invention are ordinary commercially available products and do not pose any quality problems.Although there is no particular restriction on the particle size of the additive, it is desirable that it be as small as possible. It can be used if the average particle size is 100 French or less.

The polyamide resin is a known polyamide such as nylon 6.
, homopolyamides such as nylon 66, nylon 11, nylon 12, nylon 6/66, nylon 6/12, copolyamides, and mixtures thereof.
The particle size is not particularly limited. There is no particular restriction on the method of adding and blending the additive to the polyamide resin, but it is desirable to mix it into the chips or powder before the polyamide resin is melted, that is, before or after drying. EXAMPLES The effects of the present invention will be explained below in detail with reference to Examples, but the present invention is not limited thereto.

Example: Attach a stirrer and a reflux condenser to a 1500 Z three-neck flask, 25. Add melamine (0.2 mol) and 200 ml of N,N'-dimethylformamide and boil under reflux with stirring.

17. further in 40'N,N'-dimethylformamide solvent. A solution containing tolylene diisocyanate (0.1 mol) is slowly added dropwise. After completion of the dropwise addition, the mixture was refluxed for 1 hour, cooled, and the crystals were filtered, washed with ether, and then dried.
The substance thus obtained is a substance where n=1 in the above general formula, and when further synthesizing a compound having an integer larger than n=1, the compound where n=1 synthesized above and melamine etc. are appropriately combined. It can be synthesized in xylene or a mixed solvent using amounts of this and tolylene diisocyanate in an appropriate molar ratio.
The dried substance of n=1 in the general formula obtained above was ground and crushed into nylon 6 chips (sulfuric acid relative viscosity 3.
4) as shown in Table 1, mixed in a Henschel mixer, and then melt-kneaded in an extruder to form pellets. This pellet was dried for 8 hours at a temperature of 80 qo and a pressure of 12 feet Hgads, and then processed using an injection molding machine to produce a flammability test piece specified by UL94, a dumbbell-shaped tensile test piece specified by ASTM-D-638, and an ASTM -Izod impact test pieces specified in D-256 were prepared. The mixed additives had good dispersibility and a molded product with a clean surface was obtained. The results are shown in Table 1. The test piece was tested for bleed-out, and no bleed-out was observed.

The additives used in this test were UL-rated as shown in Table 1.
In the 94 self-extinguishing property test, a polyamide resin composition was obtained which met V-0 and showed improved flame retardancy, maintained tensile strength and Izod impact strength, and had good physical properties.

Conventionally, many melamine-based compounds have been proposed as flame retardants for polyamide resins, but the inventors discovered that the compound represented by the above general formula has a remarkable effect, and developed a flame-retardant polyamide resin composition containing the compound. Obtained.

Example 2 The same test as in Example 1 was conducted using nylon 6,6 chips, and the same results were obtained, with no difference observed between the types of polyamide resins.

Example 3 Compounds corresponding to n = 2, 3, 4, 5 were synthesized using the above general formula by the method already described in Example 1, and the same tests as in Example 1 were conducted. Almost the same results were obtained, and it was confirmed that it is effective as a flame retardant.

The results are shown in Table 2.

Table 1 Table 2 Example 4 The same test as in Example 3 was conducted on nylon 66 chips using the flame retardant used in Example 3, and the same results were obtained, with no difference between the types of polyamide resins. I couldn't.

Example 5 In place of tolylene diisocyanate in Example 1, hexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, 3,3-dimethyl-
As a result of carrying out the same procedure as in Example 1 using 4,4-diphenylmethane diisocyanate and cyclohexyl diisocyanate, similar results were obtained. There were few differences among the various diisocyanates used, and all of them had excellent flame retardancy. A polyamide resin composition was obtained.

The results are shown in Table 3.

Example 6 The same test as in Example 5 was conducted using nylon 6,6 chips, and the same results were obtained, with no difference observed between the types of polyamide resins.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is an aliphatic, aromatic, or alicyclic hydrocarbon group having 1 to 20 carbon atoms, and n is 1 to represents an integer of 15.) A flame-retardant polyamide resin composition comprising a polyamide resin and an additive represented by the following.