JPH054997A - New flame-retarding compound - Google Patents

Abstract

PURPOSE:To obtain the title compound capable of imparting resins with outstanding flame-retarding effect, useful for providing plastics such as polypropylene and polyphenylene oxide with flame retardancy, by reaction between melamine and nitrilotris (methylene)phosphonic acid. CONSTITUTION:A four-necked flask with an agitator is charged with nitrilotris(methylene)phosphonic acid and water followed by heating to 70-80 deg.C and then gradually adding melamine to the system, and the resulting system is agitated at 70-80'C for one hour to carry out reaction. The resultant system is then cooled to 20-30 deg.C and the white crystal deposited is filtered and dried at a vacuum under heating, thus obtaining the objective novel flame-retarding compound consisting of nitrilotris(methylene)phosphonic acid melamine salt of the formula (M is melamine) useful for imparting plastics with flame retardancy. The nitrilotris(methylene)phosphonic acid as the raw material can be prepared by reaction between phosphorous acid, formalin and ammonia.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel phosphorus flame retardant. More specifically, it is polypropylene (PP)
It is also useful for flame retarding plastics such as polyphenylene oxide (PPO).

[0002]

2. Description of the Related Art Halides such as chlorine and bromine, phosphorus compounds, nitrogen compounds, antimony and boron inorganic compounds have been used as flame retardants for plastics. Recently, in consideration of safety, regulations on flame retardancy of plastics have been strengthened, especially bromine,
Chlorine-containing flame retardants generate toxic gas when plastics are burned, and therefore their regulations are being particularly strengthened.

[0003]

By the way, a safe phosphorus-based flame retardant has recently attracted attention as a substitute for the halogen-based material. The present invention is intended to provide a novel flame retardant which contains phosphorus and a nitrogen atom in the molecule and is effective in flame retarding PP and PPO.

[0004]

[Means for Solving the Problems]

 The present invention has the following formula:

[Chemical 2] A melamine salt of nitrilotris (methylene) phosphonic acid represented by the formula: wherein M represents melamine is provided.

The compound of the present invention can be easily prepared by dissolving nitrilotris (methylene) phosphonic acid, which is obtained from phosphorous acid, formalin and ammonia, as a raw material in a suitable solvent, and adding melamine to the mixture in an amount of about 6 times. Can be obtained. More specifically, nitrilotris (methylene) phosphonic acid is dissolved in an appropriate amount of solvent at room temperature to
Add 6 times equivalent of melamine with stirring at 90 ° C.
The solvent used is preferably water, water-acetone, or a water-alcohol mixture. Considering the stirring efficiency, the amount of solvent used is 30 to 30% of nitrilotris (methylene) phosphonic acid.
A 40-fold amount is preferable. The precipitated crystals are filtered and dried under heating under vacuum, whereby the target melamine salt of nitrilotris (methylene) phosphonic acid can be obtained in high yield.

[0006]

The following example further illustrates the present invention. Example 1 A 2-liter four-necked flask equipped with a stirrer was charged with 50 g of nitrilotris (methylene) phosphonic acid and 1800 g of water, and the temperature was 70 to 80 ° C.
To 100 g and gradually add 126 g of melamine. 70
After stirring at -80 ° C for 1 hour, the mixture was cooled to 20-30 ° C, and the precipitated white crystals were filtered and dried under vacuum under heating to obtain 162 g of melamine salt of nitrilotris (methylene) phosphonic acid. The yield was 92.0%. Next, elemental analysis of the obtained compound was performed. The results are as follows:

[0007]

[Table 1]

Example 2 Nitrilotris (methylene) phosphonic acid 50 g and water-methanol (70:30 Wt) were placed in a 2-liter four-necked flask equipped with a stirrer.
%) 1500 g of mixed solvent are charged, heated to 50-60 ° C. and 126 g of melamine are added gradually. After stirring at 50-60 ° C for 1 hour, the same procedure as in Example 1 was carried out to obtain 165 g of a melamine salt of nitrilotris (methylene) phosphonic acid. The yield was 93.8%. Next, elemental analysis of the obtained compound was performed. The results are as follows:

[0009]

[Table 2]

Example 3 50 g of nitrilotris (methylene) phosphonic acid and water-acetone (70:30 Wt%) were placed in a 3-liter four-necked flask equipped with a stirrer.
Fill 2000 g of mixed solvent and perform the same operation as in Example 2 below.
64 g of melamine salt of nitrilotris (methylene) phosphonic acid was obtained. The yield was 93.2%. Next, elemental analysis of the obtained compound was performed. The results are as follows:

[0011]

[Table 3]

Example 4 The following flame retardant test was performed: 1) Test item: UL94HB 2) Test material, method and conditions 1. Material: PP and PPO 2. Kneading method Flame retardant compounding amount: 15 parts per 100 parts of resin Kneading device: Roll 6 × 12 inch mixing roll 3. Press molding The produced sheet is press-formed to produce a lithographic plate. Planographic shape: 1.6 × 150 × 150mm Equipment: Hydraulic press 50 tons 3) The result of the combustion test is as follows:

[0013]

[Table 4] (In addition, according to the UL94HB standard, if the burning speed is 76.2 mm / min or less, the burning test standard is satisfied.)

[0014]

From the above results, the compound of the present invention, PP and PPO to which the melamine salt of nitrilotris (methylene) phosphonic acid was added, exhibited excellent flame retardant effect as compared with the resin not added. ..

Claims (1)

Claims: 1. The following formula: A melamine salt of nitrilotris (methylene) phosphonic acid represented by the formula: wherein M represents melamine.