JPH0230506A - Manufacture of polyurethane foam - Google Patents

Abstract

PURPOSE:To eliminate imbalance in foaming, by a method wherein polyol and organic isocyanate principal raw materials are led to an aging bath beforehand and uniform mixing and aging of the raw materials are performed by holding them within the bath while agitating a mixed liquid in this bath. CONSTITUTION:Fixed quantities of polyol 1 and organic isocyanate 2 are led to an aging bath 6 from a tank and both the liquids are ripened by holding within a bath while agitating them within the aging bath. Then the mixing liquid is taken out from the inside of the bath with a transfer pipe 53, mixed up with a tin catalyst 9 to be supplied by a separate system by a blender 8 provided in the course of transportation. A mixed liquid of those three is led to a mixing head 10 to which other raw materials 111, 112 are supplied further, they are discharged by agitating and mixing with each other, foamed and crosslinked.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing polyurethane foam.

In particular, the present invention relates to a method of manufacturing a foam having uniform cells.

(Prior Art) Polyurethane foam manufacturing methods include a one-stage method and a two-stage method, and a one-stage method called a one-shot method is often adopted for productivity and other reasons. An outline of this conventional method is shown in FIG. In the figure, 1 is a first raw material tank containing polypropylene glycol (PPG) 2, which is one of the main raw materials, and 3 is organic isocyanate 1, which is one of the main raw materials, such as tolylene diisocyanate (TDI).
) 4 is contained in the second raw material tank. Transfer pipes 5.6 are connected to these first and second raw material tanks, respectively, so that each raw material 2.4 in the raw material tank 1.2 is sent to the mixing head 7 by these. There is. Each of the transfer pipes 5.6 is provided with a regulating valve 8.9 in the middle, and by adjusting the regulating valve, the raw material tank 1.
The amount of raw material supplied from 2 can be adjusted as necessary. Further, each of the transfer pipes 5.6 is equipped with a pump]0.11, and by driving this, the raw material 2.4 in the raw material tank is sent to the mixing head 7. In addition to silicon (S) and a catalyst (C), other raw materials (not shown) are supplied to the mixing head 7, and all of these raw materials are mixed here to produce a foamable stock solution. This liquid is then discharged from the mixing head 7 into the mold.

The molding of polyurethane foam using the above-mentioned apparatus is carried out by adjusting the regulating valve 8.9 in the opening direction while PPG and T.
Pump 10.11 DI continuously from the raw material tank at a predetermined ratio.
While operating, send it to RAD 7 for mixing. At the same time, the catalyst, foam stabilizer (silicon),
Other water, low boiling point substances, etc. are continuously supplied through a separate system from the above, and all these raw materials are thoroughly mixed in the mixing head 7, and the foaming stock solution is discharged from the discharge port into the mold. do. The foaming stock solution discharged into the mold starts foaming immediately after being discharged, and then gels to form a polyurethane foam.

However, in these conventional polyurethane foam manufacturing methods, the mixing of the raw materials in the mixing head is not always sufficient, and various problems arise due to this.

That is, in the conventional method, all raw materials such as PPG, TDI, water, gelling catalyst, foaming catalyst, foam stabilizer, and other raw materials are collected in one place in a mixing head, and agitation, mixing, and discharge are performed continuously. However, mixing with this mixing head was not always sufficient.

If you take a long time to stir the raw materials in the mixing head, the reaction of the raw materials will start in the mixing head and the viscosity of the stock solution will increase. I can't. For this reason, it is necessary to carry out efficient stirring in a short period of time.

Until now, efforts have been made to improve the stirring efficiency of the raw material liquid by improving the structure of the mixing head, but the reality is that the situation is not necessarily satisfactory and problems still remain.

For this reason, when using the conventional method, the chemical reaction during foaming may become unbalanced, which may cause cracks in the resulting foam or abnormal reactions such as scorch. For these reasons, it has not been possible to obtain high-hardness foams from low-density waste products.

In addition, there is another prepolymer method for manufacturing urethane foam, but in this method, the viscosity is high because the reaction between PPG and TDI has already completed, and it can be easily mixed with catalyst, water, etc. as planned. does not respond and therefore TDI to this
It is necessary to adjust the reaction by adding such substances, resulting in low productivity and high costs.

(Problems to be Solved by the Invention) This invention aims to introduce polyol and organic isocyanate, which are the main raw materials for polyurethane products, into a maturing tank through a preheated transfer pipe, and to agitate the mixture inside the tank. By keeping the raw materials at a constant temperature and uniformly mixing and aging the raw materials, the aim is to eliminate the unbalance of foaming and thereby obtain good polyurethane foam without defects such as cracks and scorches that are thought to result from abnormal reactions. be.

(Means for Solving the Problems) This invention supplies polyols, organic isocyanates, blowing agents, catalysts, foam stabilizers, other necessary pigments, flame retardants, fillers, etc. to a mixing head, and mixes and stirs them. When producing polyurethane foam, a predetermined amount of polyol and organic isocyanate is introduced from a tank to an aging tank.
In this aging tank, both liquids are kept in the tank while being stirred and aged, and then this mixed liquid is taken out from the tank with a transfer pipe.
A blender provided during the transfer mixes it with a tin catalyst fed through a system different from the above, and the mixed liquid of these three is further led to a mixing head, where other raw materials are further fed, A method for producing polyurethane foam, which is characterized by stirring, mixing, discharging, foaming, and crosslinking these materials (
Claim 1), and polyol, organic isoneane-1.
When producing polyurethane foam by supplying blowing agents, catalysts, foam stabilizers, and other necessary pigments, flame retardants, fillers, etc. to a mixing head, mixing, stirring, and discharging, predetermined amounts of polyol and organic isocyanate are On the way to taking it out from the tank with a transfer pipe, these liquids are mixed in advance with a blender, and then this mixed liquid is led to an aging tank, where the mixed liquid is kept in the tank while being stirred and aged, and then This liquid mixture is taken out from inside the tank through a transfer pipe, mixed with a tin catalyst fed through a separate system from the above in a blender installed in the middle of the transfer, and the mixed liquid of these three is then guided to a mixing head. , a method for producing polyurethane foam characterized by further feeding other raw materials therein, stirring and mixing them, discharging them, foaming and crosslinking them (Claim 2)
It is. These inventions will be further explained below.

FIG. 1 shows one embodiment of the invention set forth in claim 1 of the present application. The raw materials used in this invention are the same as in the past; the main raw materials are polyol and isocyanate, and other raw materials such as a tin catalyst as a gelling catalyst and a foam stabilizer are the same as in the past. Among these raw materials, the main raw materials, polyol 1 and isocyanate 2, are extracted from each tank at a predetermined ratio by opening the respective regulating valves 31 and 32 using pumps 41 and 42, and then transferred to the transfer pipe. 51.5
2 and sent to the aging tank 6. In this aging tank 6, polyol and isocyanate are mixed in an agitator 7, and the mixed liquid is held for a certain period of time in this storage tank 6 while being stirred to ripen the mixed liquid. The retention time of the mixed liquid here is, for example, 24 to 48 hours. The thus aged mixed liquid is transferred from the aging tank 6 to the regulating valve 3.
3 is opened, the liquid is extracted with a pump 43 and sent to the blender 8 through a transfer pipe 53. A tin catalyst 9 is separately installed in the blender 8.
When the regulating valve 34 is opened, a predetermined amount of water is pumped in by the pump 44. This results in the formation of a three-way mixture of polyol, isocyanate, and tin catalyst. This liquid mixture is directly sent to the mixing head 0. Mixing head] 0, further other raw materials 11. ．． 11
2 are mixed.

These other raw materials include, for example, amine catalysts, foam stabilizers,
These include water and other fillers. In the mixing head 10, these raw materials are finally mixed to form a foamable stock solution, which is discharged from its discharge port into the mold.

What is shown in FIG. 2 shows an embodiment of the invention of claim 2 of the present application. In this figure, the same members as in FIG. 1 are indicated by the same numbers. In the same figure, the main raw materials polyol 1 and isocyanate 2 are opened with their respective regulating valves 31 and 32 open.
The liquid is extracted from each tank at a predetermined ratio using pumps 41 and 42, mixed through a blender 81 while being transferred through transfer pipes 51 and 52, and then this mixed liquid is sent to the aging tank 6. In this aging tank 6, polyol and incyanate are mixed in an agitator 7, and in this storage tank 6, this mixed liquid is held for a certain period of time while being further stirred, and this mixed liquid is aged. The retention time of the mixed liquid here is, for example, 24 to 48 hours. The subsequent steps are similar to those shown in FIG. That is, the aged mixed liquid is transferred from the aging tank 6 to the pump 43 by opening the regulating valve 33.
is extracted and transferred to a blender 82 via a transfer pipe 53.

Separately, a predetermined amount of tin catalyst 9 is fed into the blender 82 by a pump 44 with the regulating valve 34 opened.

This results in the formation of a three-way mixture of polyol, isocyanate, and tin catalyst. This liquid mixture is directly sent to the mixing head 10. In the mixing head 10, other raw materials 111, 112...
... are mixed.

These other raw materials include, for example, amine catalysts, foam stabilizers,
These include water and other fillers. In the mixing head 10, these raw materials are finally mixed to form a foamable stock solution, which is discharged from its discharge port into the mold. The invention of claim 2 differs from claim 1 in that a step of pre-mixing the polyol and isocyanate via a blender 81 is added before sending the polyol and isocyanate to the storage tank. Therefore, according to the second aspect of the invention, the mixture of polyol and isocyanate becomes even more uniform.

(Effects of the Invention) According to the present invention, the polyol and isocyanate, which are the main raw materials, are uniformly mixed and sufficiently aged, so that the final mixed liquid containing the polyol and the isocyanate, including the catalyst and other auxiliary raw materials, is foamed. The stock solution can be of very good quality. Therefore, the foaming reaction using this foaming stock solution was carried out uniformly throughout, and a foam having uniform cells without cell unevenness was obtained. Further, according to the present invention, problems such as cracks and scorch formation in the foam body are no longer caused, and the yield of products can be significantly improved.

Furthermore, the foam obtained by the present invention has excellent physical properties, and can be obtained with high hardness without deterioration even at low specific gravity. The present invention will be further explained below by giving examples.

Example 1 Using an apparatus having a raw material supply line as shown in FIG. 1, raw materials were continuously supplied from each raw material tank to a mixing head so as to have the following formulation.

Molecular weight 3000, OHHBO23 functional polyether polyotolylene diisocyanate (T-80) Triethylenediamine (amine catalyst) Normal ethylmorpholine (amine catalyst) Water dibutyltin dilaurate (tin catalyst) Silicone oil (foam stabilizer) 100 parts by weight 89. 0 0.07 0.70 0.9 1.8 Using the device shown in the figure, adjust the regulating valves 3+ and 32 in the open direction while operating the pumps 4□ and 4□, and adjust the polyether polyol and tolylene diisocyanate as described above. were introduced into the storage tank 6 through the transfer pipes 51 and 52 at a predetermined ratio of . The capacity of the storage tank 6 used here was 2000. II'. The storage tank 6 is agitated by an agitator 7, and in this agitated state, 24
The mixture was maintained for a period of time to mature. Thereafter, the operation of the agitator was stopped, and the mixed liquid was drawn out from the lower part of the storage tank 6. That is, the regulating valve 33 was opened, the pump 43 was operated, and the mixed liquid in the storage tank was continuously drawn out through the transfer pipe 53 and sent to the mixing head 10 via the blender 8. During this time, the tin catalyst 9 was added and mixed in the blender 8, and other raw materials were mixed in the mixing head 10. Other raw materials here include triethylene diamine, n-ethylmorpholine (all of the above are amine catalysts), water, and silicone oil (foam stabilizer). The final foamable stock solution thus produced was continuously discharged into the mold from the mixing head. The foaming stock solution was discharged from the mixing head at a rate of 94 kg/min, and was continuously discharged to a continuously moving groove conveyor using a conventional method to form a slab of polyurethane foam.

The density of the foam thus obtained was determined to be 19 kg/m3. Moreover, the cells of this product were very fine and uniform.

Example 2 Using an apparatus having a raw material supply line as shown in FIG. 2, raw materials were continuously supplied from each raw material tank to a mixing head so as to have the following formulation.

Molecular weight 3000, OHHBO23 functional polyether polyol 100 parts by weight tolylene diisocyanate (
T-80) 97.0 triethylenediamine (amine catalyst)
0.07 normal methylmorpholine (amine catalyst) 0.75 water

7.2 Dibutyltin dilaurate (tin catalyst)
, 0.95 silicone oil (foam stabilizer) 1.9 In the apparatus shown in the figure, adjust the regulating valve 31.32 in the open direction while operating the pump 41.42, and add the polyether polyol and tolylene diisocyanate as described above. After being drawn out through the transfer pipe 51 and 52 at a predetermined ratio, the mixture was mixed in a blender 81 and introduced into the storage tank 6. Storage tank 6 used here
The volume of is 2000, f? And so. The storage tank 6 was stirred by an agitator 7, and the mixture was kept in this agitated state for 48 hours to age the mixture. Thereafter, the operation of the agitator was stopped, and the mixed liquid was drawn out from the lower part of the storage tank 6. That is, the regulating valve 33 was opened, the pump 43 was operated, and the mixed liquid in the storage tank was continuously drawn out through the transfer pipe 53 and sent to the mixing head 10 via the blender 82. During this time, the tin catalyst 9 was added and mixed in the blender 82, and other raw materials were mixed in the mixing head 10. Other raw materials here include triethylene diamine, n-ethylmorpholine (all of the above are amine catalysts), water, and silicone/l't (foam stabilizer). The final foamable stock solution thus produced was discharged from the mixing head.

The amount of foaming stock solution discharged from the mixing head is
The mixture was discharged at a rate of 94 kg/min into an automobile cushion mold to form a polyurethane foam. The density of the foam thus obtained was measured and found to be 16 kg/m3. Moreover, the cells of this product were very fine and uniform.

[Brief explanation of the drawing]

FIG. 1 shows a system diagram of a raw material flow path according to an embodiment of the invention according to claim 1, and FIG. 2 shows a system diagram of a raw material flow path according to an embodiment of the invention according to claim 2. FIG. 3 is a system diagram showing the foam regulation of conventional polyurethane foam. 1... Polyol, 2... Isocyanate,
3, ~36...Adjusting valve, 4□~46... Pump,
5□~56...Transfer pipe, 6...Aging tank,
7... Stirrer, 81-82... Blender 9... Tin catalyst 10... Mixing head

Claims (2)

[Claims] (1) In producing polyurethane foam, polyol, organic isocyanate, blowing agent, catalyst, foam stabilizer, and other necessary pigments, flame retardants, fillers, etc. are supplied to the mixing head, mixed, stirred, and discharged. A predetermined amount of polyol and organic isocyanate is led from the tank to a maturing tank, and in this maturing tank, both liquids are kept in the tank while being stirred and aged.
After that, this mixed liquid is taken out from inside the tank using a transfer pipe, mixed with a tin catalyst fed through a system different from the above in a blender installed on the way to the transfer, and then the mixed liquid of these three is sent to a mixing head. 1. A method for producing polyurethane foam, which is characterized by introducing other raw materials, stirring and mixing them, discharging them, foaming them, and crosslinking them. (2) When polyol, organic isocyanate, blowing agent, catalyst, foam stabilizer, and other necessary pigments, flame retardants, fillers, etc. are supplied to the mixing head, mixed, stirred, and discharged to produce polyurethane foam, While taking out a predetermined amount of polyol and organic isocyanate from the tank through a transfer pipe, these liquids are mixed in advance in a blender, and then this mixed liquid is led to a ripening tank, where the mixed liquid is stirred and passed through the tank. The mixed liquid is then taken out from the tank through a transfer pipe, mixed with a tin catalyst fed through a separate system from the above in a blender installed during the transfer, and then these three The mixed liquid of
A method for producing polyurethane foam characterized by mixing, discharging, foaming, and crosslinking.