JPH0726056A - Process and apparatus for producing urethane foam - Google Patents

Abstract

PURPOSE:To simplify reaction control in the initial stage of expansion, to prevent poor mixing of the stock solution and to protect the global environment by using an isocyanate and a polyol as the principal components, adding a specified blowing agent to a mixture of these components, and expanding the resulting stock solution at a high temperature. CONSTITUTION:The process comprises expanding a stock urethane solution prepared by using an isocyanate and a polyol as the principal components and adding a blowing agent comprising HCFC-141b (hydrochlorocarbon) or HCFC-123 to a mixture of these components, and the temperature of the stock urethane solution is set at a high value. The apparatus consists of work tanks 1 and 2 which hold a first component solution 3 (comprising an isocyanate) and a second component solution 4 (comprising a polyol, a blowing agent comprising HCFC-141b or HCFC-123, a stabilizer and a catalyst), respectively. The work tanks 1 and 2 are adapted so that the first component solution 3 and the second component solution 4 may be heated by means of heaters 27 and 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a urethane foam used as a heat insulating material such as a heat insulating wall of a refrigerator.

[0002]

2. Description of the Related Art A urethane foam used for a heat insulating wall of a refrigerator is an undiluted urethane liquid prepared by stirring and mixing a first component made of isocyanate and a second component made by adding a foaming agent, a stabilizer, a catalyst and the like to polyol. Is injected into the outer shell,
It is produced by foaming the urethane stock solution in the outer shell. In this case, conventionally, a freon such as freon 11 (hereinafter referred to as "CFC-11") has been used as the foaming agent.

However, in recent years, it has been pointed out that the release of CFCs into the atmosphere adversely affects the ozone layer in the stratosphere, and from the viewpoint of protecting the global environment, it can also be used as a foaming agent for urethane foam as described above. It has been desired to switch from the conventional CFC to another. On the other hand, as a substitute for CFCs, it has been considered to use hydrochlorofluorocarbons having extremely low ozone depletion properties such as HCFC-141b or HCFC-123 as a foaming agent.

[0004]

However, the above-mentioned H
When urethane foaming is performed using CFC-141b or HCFC-123, the reaction at the initial stage of foaming becomes worse,
There was a problem that it was difficult to control the reaction in the initial stage of foaming. Further, since the viscosity of the urethane undiluted solution becomes high, there is a problem in that the undiluted urethane undiluted solution is mixed.
These problems are caused by the boiling point of HCFC-141b (32
C) or the boiling point of HCFC-123 (27.5 C) is C
It is considered to occur because it is slightly higher than the boiling point of FC-11 (23.8 ° C).

Therefore, an object of the present invention is to use H as a foaming agent.
CFC-141b or HCFC-123 can be used to protect the global environment, the reaction control in the initial stage of foaming can be simplified, and a method and a method for producing a urethane foam capable of preventing a defective mixing of the urethane raw solution To provide the equipment.

[0006]

In the method for producing a urethane foam according to the present invention, a urethane stock solution containing isocyanate and a polyol as main components and HCFC-141b or HCFC-123 as a foaming agent is foamed. Thus, the method for producing a urethane foam is characterized in that the temperature of the urethane stock solution is set high.

The urethane foam manufacturing apparatus of the present invention contains isocyanate and a polyol as main components and also uses HCFC-141b or HCFC- as a foaming agent.
An apparatus for producing a urethane foam by foaming a urethane undiluted solution containing 123 is characterized by including a temperature setting means for setting the temperature of the urethane undiluted solution high.

[0008]

The present inventor has used HCFC-141b as a foaming agent.
Or in the urethane foaming using HCFC-123,
Various experiments and studies were conducted to make it easier to control the reaction in the initial stage of foaming and to prevent the poor mixing of the urethane stock solution. As a result, if the temperature of the urethane stock solution is set higher than the set temperature (about 20 ° C.) of the conventional configuration using CFC-11 as the foaming agent, the reaction at the initial stage of foaming is as easy as that of the conventional configuration. The inventors have found that it is possible to control the mixing ratio of the urethane solution and prevent the mixing failure of the urethane stock solution, and completed the present invention.

That is, according to the above means, when the temperature of the urethane stock solution is set high (for example, about 10 ° C. high), the initial foaming reaction becomes quick, the foaming reaction can be controlled easily, and the viscosity of the urethane stock solution becomes high. As a result, the mixing ratio of the undiluted urethane solution does not occur and the quality of the urethane foam is improved. As the equipment for producing the urethane foam of the present invention, equipment having a conventional configuration can be used as it is, and in that case, it is only necessary to control the temperature so as to raise the set temperature of the undiluted urethane solution. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an apparatus for producing a urethane foam used as a heat insulating material for a heat insulating wall of a refrigerator will be described below with reference to the drawings. First, in FIG. 1 showing a schematic configuration of the entire urethane foam manufacturing apparatus, a first component liquid (hereinafter referred to as P liquid) 3 and a second component liquid (hereinafter referred to as R liquid) are provided in two work tanks 1 and 2. 4) are housed in each. The P liquid 3 is composed of isocyanate. Further, the R liquid 4 includes a polyol, a foaming agent, a stabilizer called silicone oil,
It is configured by adding predetermined amounts of catalysts such as water and amines. Here, as the foaming agent, for example, HCF
C-141b (hydrochlorofluorocarbon) is used, and CFC-11 (fluorocarbon) is not used at all. A urethane stock solution is composed of the P liquid 3 and the R liquid 4. The liquids in the work tanks 1 and 2 are constantly stirred by the stirring bodies 5 and 6. The stirring bodies 5 and 6 are configured to be rotationally driven by motors 7 and 8, respectively.

Also, one end of a P liquid supply pipe 9 is connected to the bottom of the work tank 1 for the P liquid 3, and this P
The other end of the liquid supply pipe 9 is connected to the mixing head 11 of the urethane injection device 10. The mixing head 11 has a hollow annular head portion 12, a piston 13 housed in the head portion 12 so as to be vertically movable, and is for driving the piston 13 in the vertical direction. And a cylinder portion 14 communicating with the. Oil is supplied and discharged from the hydraulic device 17 into the cylinder portion 14 via two pipes 15 and 16 connected to the upper and lower portions thereof, respectively.

The head portion 12 of the mixing head 11
One end of the P liquid recovery pipe 18 is connected to the upper part of the connection portion of the P liquid supply pipe 9 in FIG. 1, and the other end of the P liquid recovery pipe 18 is located above the work tank 1 for the P liquid 3. And is immersed in the P liquid 3. Also,
As shown in FIG. 2, a P liquid flow path 13a and an R liquid flow path 13b are formed on both side surfaces of the intermediate portion of the piston 13, and the piston 13 is located at the lower position (position shown in FIG. 1). During the operation, the P liquid supply pipe 9 and the P liquid flow path 13a
The P liquid recovery pipe 18 communicates with the P liquid circulation path 19 to form a P liquid circulation path 19. In this case, due to the pumping action of the supply pump 20 provided in the intermediate portion of the P liquid supply pipe 9, the P liquid 3 in the work tank 1 is transferred to the P liquid circulation path 1 described above.
It circulates through 9. A heat exchanger 21 for cooling the P liquid 3 flowing through the inside of the P liquid recovery pipe 18 is provided at an intermediate portion of the P liquid recovery pipe 18.

Also, the work tank 2 side for the R liquid 4 has substantially the same structure as the work tank 1 side for the P liquid 3 described above. That is, R liquid supply pipe 22, R
The liquid flow path 13b and the R liquid recovery pipe 23 communicate with each other to form the R liquid circulation path 24, and by the pumping action of the supply pump 25 provided in the intermediate portion of the R liquid supply pipe 22, R liquid 4 in the work tank 2 is the above R
The liquid is circulated through the liquid circulation path 24. Further, a heat exchanger 26 for cooling the R liquid 4 flowing through the R liquid recovery pipe 23 is provided at an intermediate portion of the R liquid recovery pipe 23.

On the other hand, the two work tanks 1 and 2 are heated by the heating devices 27 and 28 to warm the P liquid 3 and the R liquid 4 therein. The heating device 27,
28, a pipe 3 from a hot water tank 29 that stores hot water.
When hot water is supplied by the pump action of the hot water pump 31 via 0, the work tank 1,
2 is heated. The hot water after heating the work tanks 1 and 2 is configured to return from the heating devices 27 and 28 into the hot water tank 29 via the pipe 32. Here, the warm water returning to the warm water tank 29 is heated by the heater 33 provided on the pipe 32. That is, the hot water is the hot water tank 29 and the heating devices 27, 2
The work tanks 1 and 2 are heated while being circulated between the work tanks 8 and 8 and are heated by the heater 33.

The heat exchangers 21 and 26 provided in the P liquid recovery pipe 18 of the P liquid circulation passage 19 and the R liquid recovery pipe 23 of the R liquid circulation passage 24 are connected to a cold water tank 34 for storing cold water. Cold water is supplied by the pumping action of the cold water pump 36 through the pipe 35, whereby the P liquid 3 and the R liquid 4 passing through the P liquid recovery pipe 18 and the R liquid recovery pipe 23 are cooled by the cold water. Then, the cold water after cooling the P liquid 3 and the R liquid 4 is configured to return from the heat exchangers 21 and 26 into the cold water tank 34 via the pipe 37. Here, the cooler 3 provided in the pipe 37
8, the cold water returning to the cold water tank 34 is cooled. That is, the cold water is circulated between the cold water tank 34 and the heat exchangers 21 and 26 to cool the P liquid 3 and the R liquid 4 and to be cooled by the cooler 38.

A temperature sensor (not shown) including a platinum resistor, a thermocouple, a thermistor, etc. is disposed in each of the two work tanks 1 and 2, and the P liquid 3 and the R liquid are supplied by the temperature sensors. Each temperature of the liquid 4 can be detected. By inputting the temperature detection signal output from each of these temperature sensors, a control device (not shown) controls the heating power of the heater 33 and the cooling power of the cooler 38 based on each temperature detection signal. The temperature is controlled so that the temperatures of the P liquid 3 and the R liquid 4 in the work tanks 1 and 2 are maintained at the set temperatures. In this case, the control device, each temperature sensor, the heater 33, the hot water tank 29, the heating devices 27 and 28, the cooler 38, the cold water tank 34, the heat exchangers 21 and 26, and the like constitute temperature setting means. Then, in the present embodiment, the set temperatures of the P liquid 3 and the R liquid 4 are set and maintained at about 30 ° C., for example.

Next, with reference to FIG. 2, a description will be given of the work of foam-filling the urethane foam into the door 39, for example, as the outer shell of the heat insulation box of the refrigerator by the above-mentioned urethane foam manufacturing apparatus. To do. In this case, the door 39 is arranged below the mixing head 11 of the urethane injection device 10 so that the urethane injection port 39a of the door 39 and the lower end opening of the head portion 12 of the mixing head 11 face each other. In this state, when the hydraulic device 17 is driven to move the piston 13 of the urethane injection device 10 upward,
As shown in FIG. 2, the P liquid 3 supplied from the tip of the P liquid supply pipe 9 and the R liquid 4 supplied from the end of the R liquid supply pipe 22 are mixed in the head portion 12 at a constant ratio. The mixed urethane stock solution is injected into the door 39. Then, when the urethane stock solution is injected into the door 39 by a predetermined amount, the hydraulic device 17 is driven to move the piston 13 downward, and as shown in FIG. 1, the P solution circulation path 19 and the R solution circulation path are provided. 24 is formed, and the mixed injection of the undiluted urethane solution is stopped.

Here, the door 39 into which the undiluted urethane solution is injected
Within, as various polymerization reactions centered on urethane bonds between isocyanate and polyol proceed,
Due to the heat generated at this time, the foaming agent is vaporized to form bubbles, and thus urethane foam having a large number of bubbles is formed in a state of being filled in the door 39. Table 1 below shows the component composition of the urethane stock solution in this example described above. In Table 1, the component composition of the conventional urethane stock solution is also shown. In this conventional example, Freon 11 (CFC
-11) is used as a foaming agent and has been conventionally provided. The above-mentioned conventional example is also manufactured by the above-mentioned manufacturing apparatus by the same method, but the set temperature of the urethane stock solution (P solution and R solution) is set to about 20 ° C.

[0019]

[Table 1] In Table 1, the unit is weight% based on the weight of the polyol (hereinafter referred to as "PbW (Parts by Weight)").
Is used.

On the other hand, as a reference example, HCF is used as a foaming agent.
Using C-141b, and setting the preset temperature of the urethane stock solution (P solution and R solution) to 20 ° C. which is the same as the conventional example, a urethane foam was manufactured by the above-described manufacturing apparatus.
In the case of this reference example, since the rise of the urethane foaming reaction was bad (see the broken line curve A in FIG. 3), it was difficult to control the reaction in the initial stage of foaming. here,
In the graph of FIG. 3, the height dimension when urethane foam swells is measured during urethane foaming, the horizontal axis indicates time (seconds), and the vertical axis indicates height dimension (mm).
Is shown. Further, in the above-mentioned reference example, the viscosity of the undiluted urethane solution becomes high (specifically, the viscosity of the R solution is 1000 to
Therefore, there is a problem in that the undiluted urethane solution is improperly mixed. Therefore, in the reference example, the quality of the urethane foam was not good.

On the other hand, in this embodiment, HCFC-141b is used as the foaming agent, and the set temperature of the undiluted urethane solution (P solution and R solution) is set to 20 ° C. in the conventional example.
The temperature was set to be higher than that of, for example, 30 ° C., and a urethane foam was manufactured by the above-described manufacturing apparatus. In the case of this example, as shown by the solid curve B in FIG. 3, the urethane foaming reaction is accelerated, so that the reaction control in the initial stage of foaming is also easy. Here, the rise of the urethane foaming reaction shown by the solid curve C in FIG. 3 is the conventional example in which CFC-11 was used as the foaming agent, and if it is this level, the reaction control in the initial stage of foaming is easy. Then, when the set temperature of the urethane stock solution (P solution and R solution) is set to 30 ° C.,
The urethane stock solution has a low viscosity (specifically, the R solution has a viscosity of about 500 to 600 cps, and this viscosity is CF.
Since the viscosity is almost the same as that of the R liquid of the conventional example using C-11 as a foaming agent), it is possible to prevent the poor mixing of the urethane raw liquid. For this reason, in this embodiment, the quality of the urethane foam is improved to almost the same level as the conventional example using CFC-11.

Further, in the above-mentioned embodiment, as the apparatus (equipment) for manufacturing the urethane foam, the CF having the conventional structure is used.
The device used when C-11 (CFC) was used can be used as it is, and since it is only necessary to set the temperature of the urethane undiluted solution to a high temperature, switching can be easily performed, and the equipment cost is reduced. It will not be expensive.

Next, in the case of the embodiment in which HCFC-141b was used as the foaming agent and the preset temperature of the urethane stock solution (P solution and R solution) was set to, for example, 25 ° C., the rise of the urethane foaming reaction was observed. As shown by the dashed-dotted curve D in 3, the urethane foaming reaction becomes faster than in the reference example (curve A). Also in this case, it becomes easy to control the reaction in the initial stage of foaming (however, if the set temperature is 30
The rise of the reaction is slightly inferior to that of the example at 0 ° C.). It should be noted that when the set temperature is lower than 25 ° C., a very good result is not obtained.

On the other hand, in the case of the embodiment in which HCFC-141b was used as the foaming agent and the preset temperature of the urethane stock solution (P solution and R solution) was set to, for example, 35 ° C., the urethane foaming reaction started up as shown in FIG. As shown by the medium-dashed line curve E, the urethane foaming reaction starts up faster than in the reference example (curve A). Also in this case, the reaction control in the initial stage of foaming becomes easy. The set temperature is 3
If the temperature is higher than 5 ° C, mixing of the urethane undiluted solution tends to be unsuccessful, so that the good results are not obtained. Therefore, the set temperature of the urethane stock solution is 25
It is preferable to set the temperature in the range of up to 35 ° C, and among them, it is most preferable to set the temperature in the range of 30 ° C.

In each of the above embodiments, the temperature of both the P liquid 3 and the R liquid 4 is raised when the temperature of the urethane stock solution is raised, but instead of this, the R liquid (HCFC- The temperature of the liquid containing 141b) may be increased. Further, in each of the above-mentioned examples, HCFC-141b was used as the foaming agent, but instead of this, HCFC-123 may be used, and in this case also, it is almost the same as when HCFC-141b is used. The effect can be obtained.

[0026]

As is apparent from the above description, the present invention contains isocyanate and polyol as the main components and also uses HCFC-141b or HCFC-1 as a blowing agent.
In the method for producing a urethane foam by foaming the urethane undiluted solution containing 23, since the temperature of the urethane undiluted solution is set high, it is possible to protect the global environment. It is possible to easily control the reaction in the initial stage of foaming, prevent the poor mixing of the urethane stock solution, and improve the quality of the urethane foam.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a urethane foam manufacturing apparatus showing an embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view showing an injection state of a urethane injection device.

FIG. 3 is a graph showing the relationship between the temperature of the undiluted urethane solution and the rise of the urethane foaming reaction.

[Explanation of symbols]

1, 2 are work tanks, 3 are P liquids (urethane stock solutions), 4
Is R liquid (urethane stock solution), 5 and 6 are stirrers, 10 is urethane injection device, 11 is mixing head, 19 is P liquid circulation passage, 20 is supply pump, 21 is heat exchanger, 24 is R liquid circulation passage , 25 is a supply pump, 26 is a heat exchanger, 27, 2
8 is a heating device, 29 is a hot water tank, 33 is a heater, 34
Is a cold water tank, 38 is a cooler, and 39 is a door.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08G 101: 00) C08L 75:04

Claims (2)

[Claims] 1. HCFC-141b or H as a foaming agent containing isocyanate and a polyol as main components.
A method for producing a urethane foam by foaming a urethane undiluted solution containing CFC-123, wherein the temperature of the urethane undiluted solution is set high. 2. An isocyanate and a polyol as main components, and HCFC-141b or H as a foaming agent.
An apparatus for producing a urethane foam by foaming a urethane undiluted solution containing CFC-123, comprising a temperature setting means for setting the temperature of the undiluted urethane solution to a high temperature.