JPS5946260B2 - Method for producing N-alkoxymethyl polyamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing N-alkoxymethyl polyamide, and more specifically, the present invention relates to a method for producing N-alkoxymethyl polyamide. ) is a method characterized by formaldehyde treatment.

As a conventional method, when producing N-alkoxymethylated polyamide, after dissolving the polyamide in a formic acid solvent, a methanol-formaldehyde solution is added to give a solution of 60 to 7
A method is known in which the reaction is terminated at 0°C.

However, the conventional method produces waste liquid containing a large amount of formic acid,
Moreover, because the waste liquid system has a composition of alcohol-formaldehydeformic acid, which is very similar in physical and chemical terms, it is very difficult to separate and recover it by simple operations such as distillation. However, it required complicated steps such as neutralization and hydrolysis, and had the disadvantage of being costly due to the recovery and use of formic acid. In addition, since a large amount of acid is used in the reaction system, it is necessary to use equipment with good corrosion resistance, which has the disadvantage that equipment costs are extremely high. Furthermore, because the conventional method requires a low-temperature reaction of 100° C. or less at room temperature, it is difficult to obtain reactants other than relatively highly active alcohols such as methanol. Furthermore, as mentioned above, using a large amount of formic acid in the reaction system has various technical and economical problems. When producing N-alkoxymethyl polyamide, the present invention uses the target alcohol as a solvent and processes it with formaldehyde at high temperature (100°C or higher), instead of reacting in a formic acid solvent as conventionally done. This is a method of obtaining the desired object.

In this case, formic acid esters or formate salts can be used as reaction catalysts. According to this method, ethanol, propanol,
Glycol-based adducts can also be easily produced. moreover,
In the present invention, the reaction system is alcohol-formaldehyde, formic acid esters or formate salts are used as a catalyst, and the reaction is completed at high temperature and pressure, in order to solve the complexity of polymer purification and waste liquid recovery and reuse. It is.
Therefore, there is an advantage that recovery of unreacted chemicals can be completed simply by passing through a distillation process. In order to solve the above-mentioned complications, the inventors of the present invention have conducted various studies and found that when producing N-alkoxymethyl polyamide, the desired reaction is completed by completely excluding formic acid from the reaction system. This has led to the present invention.

That is, the present invention is based on a system of the corresponding alcohol and formaldehyde, and a formic acid ester or formate salt catalyst is added to carry out a high-temperature reaction in a completely sealed system, and as the reaction progresses, polyamide is converted into alcohol. This method involves dissolving it in the liquid.

The reaction formula is as follows. In this case, the alcohols that can be used include monohydric alcohols such as methanol, ethanol, propanol, and butanol, as well as polyhydric alcohols and polyglycols such as glycol and glycerin, depending on the purpose.

At this time, the reaction temperature varies from 100 to
The range j of 200°C may be selected, but in the case of relatively lower alcohols, it is better to terminate the reaction at a relatively low temperature of 100 to 150°C in order to prevent hydrolysis of the polyamide. Also, although the water content in the reaction system is not particularly important, the less water the better. Good results can be obtained in terms of increasing the substitution rate and preventing hydrolysis. Furthermore, commercially available polyamides such as nylon 6, nylon 66, 610, 12, 11, etc. can be suitably used to obtain the desired polymer, and they can be in any shape such as fibers, flakes, pellets, powder, etc. It is possible in any state.

Furthermore, if particularly high purity is not required, scrap nylon cord obtained from tire waste, plastic scrap nylon, etc. can also be used. Furthermore, formic acid esters and formate salts can be used as catalysts.

In particular, when formic acid esters are used, the advantage is that materials that can withstand reuse can be recovered by simply passing through a simple separation and purification process by distillation when refining the polymer after the reaction or recovering materials from waste liquid. Since it is not corrosive, there is no need to use special materials for the reaction equipment, etc.
There are considerable economic advantages. In this case, the amount of catalyst used is 1/1000 or more to 10% of the number of moles of polyamide.
Sufficient reaction is possible with the following number of moles, but if the amount of formic acid esters and formate salts increases, the solubility of the reaction product deteriorates, which tends to result in a heterogeneous reaction, and a good reaction product cannot be obtained. It becomes difficult to get caught. In addition, the amount of these catalysts is 5
When the amount is less than /1000, it may be difficult for the reaction to proceed sufficiently. The characteristic of this reaction is that it can be completed in a short time at high temperature, but depending on the reactivity of the alcohol used, for example, in the case of lower alcohols such as methanol and isopropanol, the reaction can be completed in 1 to 3 hours at 120 to 150 °C. However, in the case of glycols, higher temperatures or longer times may be required. When actually carrying out the reaction, first prepare the above-mentioned alcohol and formaldehyde solution, add polyamides in the form of fibers, flakes, etc., add the required amount of catalyst, seal, and adjust the temperature to the desired reaction temperature. After reacting for the required time, collect it as an alcohol solution.

In order to complete this reaction uniformly, even better results can be obtained by performing a stirring operation in the middle or final stage of the reaction. Next, the polymer recovered as an alcohol solution is poured into the formic acid ester used or into a large amount of water to separate and purify it as a powder or flake polymer.

The waste liquid generated at this time contains a large amount of formic acid esters, alcohol, and formaldehyde, so it can be removed by simple distillation at normal pressure or reduced pressure.
Can be separated and recovered. In addition, the alcohol used in the reaction system -
The formaldehyde solution composition should be around 1:1 in molar ratio, or it is possible to use a slightly larger amount of alcohol, but in order to carry out the alkoxymethylation reaction in good conditions, it is preferably around 1:1 in molar ratio. Adjust to match the ratio.

In addition, for polyamide, it is sufficient if the amount of solution is at least the amount that participates in the desired reaction, and the uniformity of the reaction varies depending on the solubility of polyamide in alcohol. 3 to 10 times the molar amount of each is required.
The details of the present invention will be described below according to Examples.
The following examples do not restrict the content of the present invention in any way. ★ --Example 1 0.1 mole of nylon 6 was added to 0.1 mole of methanol prepared in advance.
The tube was placed in a solution of 4 mol-0.4 mol of paraformaldehyde and 0.04 mol of methyl formate, sealed, and reacted at 130° C. for 2 hours under about 9 atmospheres.

The reaction solution was poured into a large amount of methyl formate to recover flaky white polymer. This resin was a flexible resin that dissolved in cold methanol. Further, the N-substitution rate calculated from the infrared absorption spectrum was about 34%. Example
2 Place 0.1 mol of nylon 6 fibers in a previously prepared methanol-formaldehyde solution with the following composition, and after sealing the tube,
The reaction was carried out at 130° C. for 3 hours under atmospheric pressure.

After the reaction was completed, the solution was poured into a large amount of water, and the reactant was purified and recovered.

The resulting resin was white and flexible. Examples 3 to 8 0.02 mol of nylon 66 was placed in a methanol-formaldehyde solution having the following composition containing 0.08 mol of methyl formate, and after sealing the tube, the reaction was carried out at 135°C for 2 hours under about 9 atm. The influence of water in the reaction system was investigated.

After the reaction was completed, the solution was poured into a large amount of methyl formate to obtain a flaky polymer, which was dried, treated with 1007 1% aqueous sodium sulfite, washed with water, and dried again to obtain the desired product. As can be seen from the table above, the reaction proceeds to some extent even if the amount of water is quite large, but a better reaction can be expected with less water.

Examples 9 to 12 0.02 mol of pelleted nylon 6 was placed in a reaction solution having the composition shown in the table below, sealed, and reacted at 130°C for 2 hours under about 10 atm. of acetone to obtain a white resin.

The resulting resin was methanol soluble and flexible. As shown in the above examples, it is also possible to appropriately adjust the pressure within the reaction system by adding another formalin inert solvent to the alcohol-formaldehyde solution.

As explained above, since the present invention uses formic acid esters or formic acid salts as a catalyst, the following effects can be expected compared to conventional reaction systems using formic acid as a solvent.

Since the reaction is carried out using a catalyst system containing only a small amount of methanol and formaldehyde, the polymer can be purified and the solvent system can be easily recovered and reused.

Furthermore, since there is no need for complicated processing steps unlike in the case of conventional methods that contain a large amount of formic acid, it can be recovered and reused at a relatively low cost. Compared to the conventional method, which uses a large amount of diformic acid, the equipment is less corrosive and does not require special materials for the equipment.

3.Therefore, equipment costs are low.

The formic acid method had the disadvantage that it was difficult to obtain reactants other than relatively highly active reactants, such as methanol, because the reaction was carried out at normal pressure and at 60 to 70°C.However, according to the method of the present invention, as mentioned above, , it is possible to produce various alcohol adducts with considerable freedom.

Further, as an applied field, the product according to the present invention has excellent oil resistance, so it can be used as an oil-resistant sealing material, packing material, and other processing and finishing agents for textiles.

Claims (1)

[Scope of Claims] 1. An N-alkoxymethyl polyamide characterized by reacting polyamides in an alcohol-formaldehyde solution at elevated temperature using at least one of formic acid esters and formate salts as a catalyst. manufacturing method. 2 The amount of the catalyst used is 1 molar ratio to the polyamides.
/1000 to 10, and the reaction under elevated temperature is 10
A method for producing N-alkoxymethyl polyamide according to claim 1, which is carried out at a temperature of 0 to 200°C.