JPS63183926A - Production of polycarbonatediol - Google Patents

Abstract

PURPOSE:To readily produce a polycarbonatediol having optionally adjusted urethanization reactivity without requiring an additive with excellent reproducibility, by cooling a reaction product from a state of a high temperature while controlling cooling rate at completion of the reaction. CONSTITUTION:A polycarbonatediol is produced from ethylene carbonate and 1,6-hexanediol and the produced polycarbonatediol in a state of a high temperature at completion of the reaction is cooled to 160 deg.C temperature while controlling cooling rate then to ordinary temperature. Thereby the aimed compound having adjusted urethanization reactivity is obtained. The preferred range of the cooling rate is 1-300 deg.C/hr, more preferably 3-250 deg.C/hr. The cooling rate is reduced at a high temperature and increased at a relatively low temperature to afford the product having relatively vigorous urethanization reactivity.

Description

[Detailed description of the invention] [Industrial application field] This invention can be used as an elastomer for various molded products.

It also relates to a method for producing polycarbonate diol, which exhibits excellent performance as a raw material for polyurethane, which is widely used in adhesives, paints, etc., and is widely used in various industries that use polyurethane.

[Conventional technology]

Polyurethane is obtained by reacting diol and isocyanate. For example, polyurethane elastomer is obtained by reacting a predetermined amount of diol and diisocyanate.
After being made into pellets, they are subjected to molding processing.

In this case, if the urethanization reactivity of the diol is too fast, the reaction will proceed too much in the reactor, making it difficult to take out the product from the reactor.

On the other hand, when a diol and isocyanate are reacted using a catalyst in an organic solvent, it is not a good idea to use a diol whose urethanization reactivity is too slow in terms of production time and other aspects. It often becomes necessary to increase the amount of catalyst added to promote the urethanization reaction.

However, this cannot be said to be economical in terms of the cost of the catalyst.

For the above reasons, there is a demand for diols having various urethanization reactivities depending on the purpose.

Currently, among various diols, moisture, diol manufacturing raw materials, low molecular weight compounds, Organometallic compound catalysts containing tin, titanium, etc., other alkalis, amines, etc., and those that delay the urethanization reaction include oxyacids.

Acid components such as phosphoric acid and P-toluenesulfonic acid are known. (Refer to pages 7 to 44 of "Polyurethane Resin" by Keiji Aida) [Problems to be Solved by the Invention] As mentioned above, various means for urethanization reactivity of diols can be used in the reaction with diisocyanate. The main thing is to add additives.

However, the addition of such various additives may color the resulting polyurethane and impair its appearance.

Physical properties of polyurethane caused by added compounds.

For example, there is a risk of deterioration in water resistance, heat resistance, cold resistance, texture, etc., so its use is by no means preferable, and addition of various additives is also economically disadvantageous.

Therefore, it would be most convenient if it were possible to obtain a diol whose urethanization reactivity was adjusted in advance during production of the diol, but at present no means for adjusting the reactivity has been found, and in particular, there is no knowledge regarding polycarbonate diols. It doesn't exist at all.

[Means for solving problems]

In view of the current situation, the present invention aims to obtain a polycarbonate diol having any urethanization reactivity when producing a polycarbonate diol obtained by the reaction of ethylene carbonate and 1,6-hexanediol.

That is, this invention combines ethylene carbonate and 1,6
- In the process of producing polycarbonate diol from hexanediol and cooling the produced polycarbonate diol, which is in a high temperature state after the completion of 2 reactions, to room temperature, 1
This is a method for producing polycarbonate diol, which is characterized in that polycarbonate diol whose urethanization reactivity is controlled is obtained by controlling the cooling rate during cooling from a high temperature state at the end of the reaction to a temperature of 160°C.

As mentioned above, this invention comprises ethylene carbonate and 1,
The cooling rate of polycarbonate diol after the reaction with 6-hexanediol is controlled, and the reaction between ethylene carbonate and 1,6-hexanediol is an equilibrium reaction by transesterification.

The reaction temperature immediately after the reaction is completed.

In other words, the temperature of the produced polycarbonate diol is approximately 1
Since the polycarbonate diol is at a high temperature of 80°C to 250°C, the polycarbonate diol produced after this reaction is finally cooled to around room temperature to produce a product. In the process of cooling.

This is to adjust the cooling rate when cooling from a high temperature state to a temperature of 160°C.

The desired objective is achieved by adjusting the cooling rate within the above temperature range.

Therefore, no matter how much the cooling rate is controlled in a temperature range lower than 160°C, the cooling rate control that was being performed in this temperature range will be stopped midway, that is, at a temperature higher than 160°C. It is also unsuitable for controlling urethanization reactivity.

In this case, the control that was performed between the high temperature state and the temperature of 160°C is preferably performed at a temperature of 140°C in order to more appropriately control the urethanization reactivity.

More preferably, it is desirable to continue the heating up to a temperature of 120°C.

It is of course possible to continue this control to around room temperature, but control in the low temperature range of 160°C or less does not have a very sensitive effect on the adjustment of the urethanization reactivity of polycarbonate diol, Especially temperature 12
There is no effect at all below 0°C, so the temperature is 120°C.
From an economic point of view, it is desirable to take measures such as limiting the temperature to about ℃ and then leaving it to cool naturally or cooling it rapidly.

The preferable range of the cooling rate to be controlled in this temperature range is 1-b. The effect on urethanization reactivity is reduced.

On the other hand, if the cooling rate is higher than 300° C./hr, it is not economical because a large amount of equipment is required for cooling.

The cooling rate may be controlled at a constant cooling rate under the above conditions, or may be changed during cooling.

Generally, if the cooling rate in this temperature range is high, a polycarbonate diol with slow urethanization reactivity will be obtained, and conversely, if the cooling rate is low, a polycarbonate diol with rapid urethanization reactivity will be obtained. has.

Furthermore, when changing the cooling rate, the cooling rate should be reduced when the liquid temperature is high within the above temperature range.

As the temperature decreases, the cooling rate increases (by doing so, the polycarbonate diol has a relatively rapid urethanization reactivity; conversely, the cooling rate is increased at high temperatures, and the cooling rate is decreased at relatively low temperatures) This makes it possible to obtain polycarbonate diols having slow urethanization reactivity.

Therefore, by controlling the cooling rate in this way, it is possible to freely obtain polycarbonate diol having any urethanization reactivity.

In this invention, as a method for adjusting the cooling rate, the polycarbonate diol may be cooled by external cooling while it is present in one reactor, or it may be transferred to another container and carried out in the same manner. .

The reaction for producing ethylene carbonate diol in this invention will be described below.

Ethylene carbonate, the raw material used in this invention, is a compound that is crystalline at room temperature with a melting point of 36.4°C, so it can be supplied to the 9 reactors in the form of crystals. It is desirable to supply

Ethylene carbonate is virtually non-toxic and therefore does not require any special care in handling.

1,6-hexanediol, which is another raw material, is also a compound that is crystalline at room temperature like ethylene carbonate, and can be supplied to the 9 reactor in the same form as ethylene carbonate.

There is no restriction on the order of addition of ethylene carbonate and 1,6-hexanediol, either one may be added first,
Alternatively, they may be added at the same time.

However, ethylene carbonate undergoes a decomposition and decarboxylation reaction at high temperatures, and the resulting ethylene oxide undergoes ring-opening condensation to form an ether bond.

It is most desirable to appropriately control the concentration of ethylene carbonate in the reaction solution and supply it in portions or continuously.

It is possible to produce polycarbonate diol if the ratio of ethylene carbonate and 1.6-hexanediol is about 1/10 to 10/1 as a 9 molar ratio, but if the ratio is 1/10 to 10/1,
1.5 to 1.5/1 is more economical.

In the present invention, it is not necessary to use a catalyst in the two reactions, but there is no restriction on the use of a catalyst that does not interfere with obtaining polyurethane from the obtained polycarbonate diol.

Furthermore, even if a catalyst is used that is a hindrance, it can be used effectively by removing this catalyst.

As an effective catalyst, a transesterification catalyst such as diptyltin dilaurate can be recommended.

The reaction is a transesterification reaction between ethylene carbonate and 1,6-hexanediol, and is an equilibrium reaction, so it is preferable to quickly remove by-product ethylene glycol from the reaction system. Since the boiling point and viscosity of ethylene glycol increase, it is desirable to increase the temperature accordingly in order to remove the by-product ethylene glycol and promote the reaction.

Therefore, it is preferable to control the reaction temperature to 100° C. to 200° C. at the start of the second reaction, and to 180° C. to 250° C. at the end of the reaction.

When the reaction temperature is less than 100°C, the reaction rate is low.

Moreover, if the temperature is higher than 250°C, the raw materials and the polycarbonate diol produced will decompose, which is not preferable.

The reaction pressure is preferably reduced in order to efficiently separate and remove by-product ethylene glycol.

It depends on the reaction temperature, but at the start of the reaction 30 to 300. T
.

rr, then gradually increase the reduced pressure and finally 1 to 30
It is best to reduce the pressure to Torr.

As mentioned above, it is desirable to remove the by-product ethylene glycol during the reaction, but in order to effectively utilize the raw materials ethylene carbonate and 1,6-hexanediol, it is necessary to install a rectification means in one reactor. preferable.

Here, the completion of the reaction can be determined by measuring the melt viscosity of the reaction liquid collected from the 9 reaction system, and this melt viscosity is 600 to 80 °000 cps at a temperature of 50 °C.
It will end when this happens.

At that time, if unreacted raw materials and by-product ethylene glycol remain in the reaction solution, the accuracy of the above analysis will decrease, and undesirable side reactions will occur when obtaining polyurethane using the obtained polycarbonate diol, so one reaction ends. Sometimes it is desirable to completely remove these unreacted raw materials and by-product ethylene glycol.

If the melt viscosity is 600 cps, it becomes difficult to completely remove unreacted raw materials and by-product ethylene glycol, making it difficult to control the polycarbonate diol production reaction well.

Furthermore, even if one attempts to obtain a product with a melt viscosity exceeding 80,000 cps, the reaction takes a long time at a high temperature, so that aldehydes, carboxylic acids, etc. are produced as by-products, making it difficult to control the reaction.

The temperature of the reaction solution at the end of the reaction is 180 to 250 DEG C., and by adjusting the cooling rate of the reaction solution under the conditions described above, a polycarbonate diol having the desired urethanization reactivity can be obtained.

The polycarbonate diol thus obtained has a melting point of 40°C.
These compounds are solid at room temperature, and can be filled into a container in a molten state, or, if necessary, can be made into flakes using a flaker to form a product.

When using polycarbonate diol as a raw material for polyurethane, it is desirable to have a small amount of water, so that the filling does not absorb moisture during storage.

It is desirable to use a hermetically sealed stopper or to seal it with an inert gas such as nitrogen.

[For production]

In place of the conventional means for adjusting the urethanization reactivity of polycarbonate diol, which was carried out only by the addition of additives, the present invention provides a method for cooling polycarbonate diol produced in a high temperature state after the completion of two reactions, by reducing the temperature by 1 degree from the reaction temperature.
This method controls the urethanization reactivity of polycarbonate diol obtained by controlling the cooling rate in a limited temperature range up to 60°C. ,
By keeping the reaction solution at a relatively high temperature for a long time.

Considering the fact that the urethanization reactivity increases rapidly,
At high temperatures, polycarbonate diol or other substances coexisting with it are decomposed.

It is presumed that this causes rapid urethanization reactivity.

The method of the present invention not only makes it extremely easy to adjust the urethanization reactivity, but also has the outstanding advantage of economically producing polycarbonate diols having various urethanization reactivities. It is.

In addition, according to the present invention, there is no coloring or side reactions caused by additives, and there is no deterioration of the physical properties of polyurethane. can be adjusted.

〔Example〕

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

Sue cliff - 5I with uneven stirrer, temperature needle, and fractionation tube! In a glass flask, 1. ．． After adding 2.3 kg of 6-hexanediol and heating and reducing the pressure to 150° C. and 50 Torr, ethylene carbonate was supplied at a rate of 0.3 kg/hour for 6 hours while gradually increasing the temperature and the degree of pressure reduction.

17 hours after the start of the reaction, the temperature was 210°C and the pressure was 3T.

The temperature and the degree of pressure reduction were increased until the temperature was 50° C., and 3.0 kg of polycarbonate diol having a melt viscosity of 9.000 cps at a temperature of 50° C. was obtained.

This polycarbonate diol was divided into glass flasks equipped with a stirrer while maintaining the temperature at 210°C, and the polycarbonate diol was divided into glass flasks equipped with a stirrer while maintaining the temperature at 210°C.
It was cooled to 60°C and then allowed to cool naturally to room temperature.

Table 1 shows the results of measuring the urethanization reactivity (time) of the polycarbonate diol thus obtained.

The urethanization reactivity test method was carried out as follows.

That is, 250 parts of polycarbonate diol was heated at a temperature of 8
The temperature was maintained at 0°C, and 34 parts of diphenylmethane diisocyanate, which had been separately heated to 80°C, was added thereto with stirring.

The temperature increase and viscosity increase due to the urethanization reaction were tracked over time, and the time until the viscosity reached 200 poise was measured and used as an index of urethanization reactivity.

Table 1 Note that the polycarbonate diol obtained above at a temperature of 210°C was cooled at a cooling rate of 25°C/hr until the temperature reached 80°C, and then allowed to cool naturally until it reached room temperature.

The urethanization reactivity of the polycarbonate diol thus obtained was 11 minutes, and even if the cooling rate was adjusted until the temperature of the polycarbonate diol reached 80°C, when the cooling rate was adjusted to the above-mentioned temperature of 160°C. There was no change in urethanization reactivity.

〔Effect of the invention〕

In this invention, the liquid temperature of the product in the reaction between ethylene carbonate and 1,6-hexanediol is determined.

By controlling the cooling rate during cooling from the high temperature state to 160°C after the completion of the reaction, the desired urethane formation can be achieved without using any additives to impart urethane reactivity. A reactive polycarbonate diol can be freely obtained.

Therefore, polycarbonate diol as a raw material for polyurethane used in a wide range of fields can be easily produced with good reproducibility without using any special additives.

Further, in this invention, ethylene carbonate used as a raw material has almost no toxicity.

It is advantageous in that it does not require any special care when handling, so it has extremely high utility value.

Claims (1)

[Claims] In the process of manufacturing polycarbonate diol from ethylene carbonate and 1,6-hexanediol and cooling the produced polycarbonate diol, which is in a high temperature state after the reaction is completed, to room temperature, cooling from the high temperature state at the end of the reaction to a temperature of 160 ° C. 1. A method for producing polycarbonate diol, which comprises obtaining a polycarbonate diol with controlled urethanization reactivity by controlling the cooling rate during the process.