JPS5910339B2 - Polyol manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyol by adding an alkylene oxide to a distillation residue of tolylene diamine.

Tolylene diamine is an intermediate raw material in the production of tolylene diisocyanate, and is usually obtained by distilling and purifying crude tolylene diamine.

This distillation purification is carried out industrially continuously, and the distillation residue that is discarded at the time is currently not effectively utilized and is mainly disposed of by incineration. However, there are currently many problems in processing this distillation residue, such as premature damage to the furnace when incinerated. It is already known to produce a polyol by adding an alkylene oxide to the purified tolylene diamine obtained by the above distillation purification, and to produce a polyurethane foam from the polyol and diisocyanate. Therefore, the present inventors investigated various ways to effectively utilize this distillation residue, and as a result, they succeeded in producing a new polyol by effectively utilizing the active hydrogen groups existing in the distillation residue. .

That is, the present invention is a method for producing a polyol by adding an alkylene oxide to a distillation residue of tolylene diamine. Furthermore, surprisingly, the polyol of the present invention not only has higher reactivity with isocyanate groups than the aforementioned polyol made from purified tolylene diamine and alkylene oxide, but also has a high reactivity with isocyanate groups. It was found that the polyurethane foam obtained by using the present polyol itself has far superior flame retardancy without adding any flame retardant, leading to the present invention. This excellent flame retardancy is thought to be due to the formation of -N=N- bonds through the reaction between the nitro groups remaining in the distillation residue of tolylene diamine and the amino groups. The distillation residue of tolylene diamine of the present invention refers to the residue after distilling crude tolylene diamine obtained by reducing dinitrotoluene etc. to obtain purified tolylene diamine, and the chemical composition is Although it varies greatly depending on the distillation conditions, 60-95% of the amino group-containing polymer produced from tolylene diamine and nitro compounds remaining as impurities, and 5-4% of free tolylene diamine.
It is a resin-like substance at room temperature.

The alkylene oxide used in the present invention includes ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof, but propylene oxide is usually used.

If desired, the alkylene oxide may be added to the reaction in one or more steps. The reaction conditions of the distillation residue of tolylene diamine and the alkylene oxide may be similar to known techniques for the reaction of alkylene oxide with compounds containing active 5 hydrogen groups.

i.e. a temperature of 50 to 150°C, in particular 90 to 120°C, 36
Pressures up to 1 kg/kg can be used. Basic catalysts, such as potassium hydroxide, can be advantageously used. The alkylene oxide is usually introduced into the reaction system at a rate sufficient to maintain the desired temperature and pressure. The amount of alkylene oxide used in the reaction is preferably 1 mole or more per active hydrogen group in the distillation residue of tolylene diamine in order to maintain the obtained polyol in a liquid state at room temperature. After completion of the reaction, the catalyst is removed from the polyol if necessary by conventional methods, for example by neutralization with acids or treatment with carbon, natural or synthetic absorbents or mixtures thereof, followed by filtration. You can.

If desired, the distillation residue of tolylene diamine can be combined with one or more other compounds containing a large number of active hydrogen groups, such as xylylene diamine, other polyamines such as triphenylmethane triamine, and/or glycerin, triamine, etc. Oxyalkylation can also be carried out in the form of a mixture with polyols such as methylolpropane and 1,4-butanediol.

The polyols produced by the process of the invention have a high reactivity towards isocyanate groups and are particularly advantageous for producing cellular or non-cellular polyurethane materials using known general methods.

The polyols according to the invention can then be reacted with organic polyisocyanates, optionally in the form of mixtures with other monomeric or polymeric polyols, if desired, for example in the presence of gas generants and other customary additives. Next, the present invention will be specifically explained using examples.

*． ×In the examples, "parts" and "%" are "parts by weight" and "% by weight"
”. Example 1 Amine equivalent weight 7 containing 25% free tolylene diamine
760 parts of a distillation residue of 6r/MOl of tolylenediamine and 3 parts of potassium hydroxide are charged into a stainless steel reactor and heated and melted at 130° C. under a nitrogen atmosphere.

Stirring was started, and the pressure was reduced to 601!1 Hg for 1 hour to dehydrate. After returning to normal pressure, 900 parts of propylene oxide was heated to 110 to 130°C for 10 hours using a pressure pump for a maximum of 3.
After adding under the condition of 0 kg/Crlt, the reaction is continued at the same temperature until the pressure returns to normal pressure. After the reaction was completed, the pressure was reduced to remove unreacted propylene oxide, and then 4.4 parts of acetic acid was added to neutralize the catalyst, and the mixture was passed through a 150-mesh strainer to achieve a hydroxyl value of 350T! 1fK0H/t polyol 1
600 copies were sold. Example 2 120 parts of the same distillation residue of tolylenediamine as in Example 1, 50 parts of triethanolamine, and 1.0 parts of potassium hydroxide.
0 part was charged into a stainless steel reactor and dehydrated by reducing the pressure to 130° C. under a nitrogen atmosphere.

After returning to normal pressure, add propylene oxide 2 with a pressure pump.
30 parts for 8 hours, 110-130℃, maximum 3.0k
After adding under the condition of g/CllL, the reaction is continued at the same temperature until the pressure returns to normal pressure. After the reaction was completed, the pressure was reduced, unreacted propylene oxide was removed, and 1.6 parts of acetic acid was added to neutralize the catalyst. Polyol 39 with a hydroxyl value of 370'1f1fK0H/f was passed through a 150-mesh strainer.
I got 0 copies. In this case, the foaming rate, that is, the reactivity to diisocyanate, was as shown in Table 2. It is clear from the above table that the reactivity of the present polyol with polyisocyanate is much higher than that of the propylene oxide addition polyol of purified tolylene diamine.

Reference example For comparison, hydroxyl value 360}Tn9KOH
Polyurethane foam was produced using the propylene oxide addition polyol of purified tolylenediamine of /V and the polyols obtained in Examples 1 and 2 of the present application according to the formulation shown in Table 1.

The physical properties of the obtained foam were as shown in Table 3.

From the table above, when the polyol of the present invention was used, good results were shown in terms of flame retardancy (evaluated by oxygen index).

Claims (1)

[Claims] 1. A method for producing a polyol by adding alkylene oxide to a distillation residue of tolylene diamine.