JPH03150109A - Production equipment of expandable urethane stock liquid - Google Patents

Abstract

PURPOSE:To manufacture urethane foam with a simple production equipment without danger of the destruction of atmospheric ozone layer by a structure wherein an adsorption mixing tower consists of an adsorption zone, in which silica gel particles come into contact with expandable gas during their fall in the tower so as to adsorb the gas and which locates at the upper part of the tower, and a mixing zone, in which the expandable gas-adsorbed silica gel particles and polyol stock liquid are mixed together and which locates at the lower part of the tower. CONSTITUTION:The predetermined amount of polyol stock liquid is supplied from liquid tanks 12 by the actuation of metering pumps 13 through lines 14 in a mixing zone 1B at the lower part of a tower 1. The predetermined amount of silica gel particles is supplied from a powder tank 9 by opening a powder valve 11 through a line 10 in the tower 1. The silica gel particles supplied in the tower 1 come into contact with expandable gas filled in the tower during their falling with their selfweight in the adsorption zone 1A at the upper part of the tower 1. The amount of gas consumed by adsorption is properly replenished in the tower from a pressure tank 5 by opening a valve 8. The silica gel particles, onto which gas is adsorbed, fall in the mixing zone 1B at the lower part of the tower 1 and are mixed with polyol stock liquid, resulting in obtaining expandable urethane stock liquid.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an apparatus for producing a foamable urethane stock solution.

Conventionally, a foamable urethane stock solution prepared by adding a foaming agent that is liquid at room temperature, such as trichloromonofluoromethane, to a polyol stock solution has been proposed. When this foaming urethane stock solution is mixed with an isocyanate stock solution, the blowing agent (liquid) is vaporized by the heat of reaction, and urethane foam with good heat insulation properties can be obtained by simply mixing the two liquids. In addition, it can be easily achieved in terms of operation.

However, trichloromonofluoromethane, which is liquid at room temperature and is often used as a blowing agent, has the property of destroying the ozone layer in the atmosphere, and its production and use tend to be prohibited. Blowing agents that are liquid at room temperature, such as saturated water, methylene chloride, and pentane, pose no danger of destroying the ozone layer, but they have the problem of poor heat insulation performance.

Dichlorodifluoromethane, which is a gas at room temperature, has the advantage of having excellent heat insulation properties, but there is a risk of destroying the ozone layer.Furthermore, since it is a gas at room temperature, high-pressure injection is required, which complicates equipment and operation. Furthermore, since the cells are likely to communicate with each other, it is not suitable for producing closed-cell heat insulating foam.

The present invention has been made with the aim of eliminating such conventional problems.

Means for Solving the Problems The present invention provides a supply section for a foaming gas which is a gas at room temperature, a supply section for silica gel particles, a supply section for a polyol stock solution, and a supply section for supplying the foaming gas, silica gel particles and polyol from each supply section. The adsorption mixing tower is equipped with an adsorption mixing tower that receives the supply of the raw solution. This relates to an apparatus for producing a foamable urethane stock solution, characterized in that the lower part is equipped with a mixing zone for mixing the foamable urethane stock solution.

In the present invention, the foaming gas supply section is equipped with, for example, a pressure vessel, and the foaming gas is stored in the container. The foaming gas must be a gas at room temperature, have no risk of destroying the atmospheric ozone layer, and be inert to the polyol stock solution. Examples include difluoroethane.

The silica gel particle supply section is equipped with, for example, a powder tank, and the supply from the tank is performed by falling under its own weight. The particle size of the above particles should be as small as possible in order to reduce the falling speed in the tower and increase the contact time with the foaming gas, but if it is too small, it may be difficult to mix with the polyol stock solution, and the fine shape after mixing may be affected. Since there is a risk of adversely affecting the moldability of the material, a material having a diameter of about 20 to 150 microns, preferably about 30 to 75 microns is used.

The polyol stock solution supply section is equipped with, for example, a liquid tank, and the supply from the tank is carried out, for example, by applying a metering pump.

The adsorption mixing tower is equipped with an adsorption zone in the upper part where the silica gel particles are brought into contact with the foamed gas, and a mixing zone in the lower part where the gas adsorbed silica gel particles and the polyol stock solution are mixed. A stirrer may be provided in the column, and the container may include a stirring blade that rotates in the mixing zone, a spiral blade that rotates in the adsorption zone, and generates a vortex flow (26).
can.

When producing a foamable urethane stock solution, the upper adsorption zone in the adsorption mixing column is filled with foaming gas. It is desirable that this gas filling is performed after the air inside the tower is discharged.

Next, a predetermined amount of silica gel particles are continuously allowed to fall in small amounts under their own weight into the filled gas, and during this fall, the silica gel particles come into contact with and adsorb the gas. The silica gel particles have a small particle size of about 20 to 150 μm, and fall slowly in the tower, so that the particles can sufficiently adsorb the gas by utilizing the time during which they fall. In order to extend the contact time between the particles and the gas, a vortex may be formed in the gas to cause the particles to swirl downward.

The silica gel particles should be mixed with the above gas at a maximum of 1:0.4 to 0.
．． 6 (weight ratio) can be adsorbed.

After completing the gas adsorption operation for a predetermined amount of silica gel particles,
In the mixing zone at the bottom of the column, a predetermined amount of gas-adsorbing particles and a predetermined amount of the polyol stock solution are mixed. In this case, the polyol stock solution may be supplied into the column either before or after the gas adsorption operation.

The mixing ratio of the polyol stock solution and the silica gel particles can be selected from a wide range, and is usually set in a range such that the amount of gas is about 0.1 to 0.3 mol per 100 grams of the polyol stock solution.

A foamable urethane stock solution is obtained by mixing the polyol stock solution and the gas adsorption particles.

When a foaming urethane stock solution and an isocyanate stock solution are mixed together with various known additives such as catalysts, foam stabilizers, crosslinking agents, flame retardants, fillers, etc., gas is desorbed from particles due to the reaction heat of the two stock solutions, causing foaming. , a beneficial urethane foam can be obtained.

Therefore, when manufacturing urethane foam, it is possible to apply the same equipment and operations as those used for foaming urethane stock solutions that use a liquid blowing agent at room temperature, and the purpose of manufacturing urethane foam can be easily achieved in terms of equipment and operation. Furthermore, since a foaming agent that is gaseous at room temperature can be used, there is no risk of depletion of the atmospheric ozone layer.

Furthermore, there is no need for dangerous operations such as high-pressure injection.
There is no risk of deteriorating the working environment.

Embodiments Below, embodiments of the apparatus of the present invention will be explained based on the accompanying drawings.

FIG. 1 shows an embodiment of the apparatus of the present invention, in which an adsorption mixing column (1
) has an adsorption zone (IA) in the upper part and a mixing zone (IB) in the lower part. An exhaust line (2) is attached to the top of the column (1), and a vacuum bomb (
3) and an on-off valve (4).

Outside the column (1), a foaming gas supply section for gas at room temperature, for example a pressure vessel (5), is provided, and a predetermined amount of the above gas is stored under pressure in the vessel (5).

The pressure vessel (5) is connected to the column (
1), and a regulator (7) and an on-off valve (8) are provided on the line (6).

A supply section for silica gel particles, for example a particle tank (9), is provided above and outside the opening (1), and the tank (9) is filled with the particles. The lower end of the tank (9) is connected to the top of the upper air column (1) via a powder supply line (10), on which a powder valve (11) is provided. The supply of silica gel particles from the tank (9) to the column (1) is preferably carried out in a state where contact with outside air is prevented as much as possible in order to prevent adsorption of other components.

Furthermore, outside the column (1), a supply section for the polyol stock solution, for example a liquid tank (12), is provided, and the lower end of the tank (12) is connected to a liquid supply line (14) equipped with a metering pump (13).
) to the lower mixing zone (IB) in the column (1). Although the figure shows a case where three tanks (12) are provided, the number of tanks (12) installed is not particularly limited.

Furthermore, a discharge line (16) with a metering pump (15) and a valve (17) is attached to the lower end of the column (1). The other end of the line (16) is connected to a packaging line (not shown), for example for product (undiluted solution) packaging. Alternatively, it is connected to a mixing head (not shown) of a molding device for mixing with an isocyanate stock solution and molding urethane foam.

The adsorption mixing column (1) is equipped with a stirrer (19), and the vessel (
At the lower end of the rotating shaft (20) of 19), there is a mixing zone (IB).
A stirring blade (21) is provided which is rotated within the container. In addition, in the figure, (22) is a level sensor, and (23) is a pressure sensor.

When producing a foamable urethane stock solution using the apparatus of the present invention, first, the vacuum pump (3) on the line (2) is activated to exhaust the air in the adsorption mixing column (1), and the column (
1) After the inside reaches a predetermined degree of vacuum, the valve (4) on the line (2) is closed.

The valve (8) on the gas supply line (6) is then opened;
Foaming gas is supplied from the pressure tank (5) through the line (6) into the tower (1), and after the inside of the tower (1) reaches a predetermined pressure, for example, normal pressure, the valve (8) is closed. Supply will be stopped.

On the other hand, a predetermined amount of polyol stock solution is supplied from the liquid tank (12) into the mixing zone (18) in the lower part of the column (1) through the line (14) by operating the metering pump (13).

Next, a predetermined amount of silica gel particles are supplied from the powder tank (9) into the column (1) through the line (10) with the powder valve (11) opened.

While the silica gel particles supplied into the tower (1) fall under their own weight in the adsorption zone (IA) in the upper part of the tower (1), they come into contact with the filling gas for foaming, adsorb it, and are absorbed and consumed. The amount of gas is appropriately replenished into the column from the pressure tank (5) by opening the valve (8).

The silica gel particles that have adsorbed the gas fall into the mixing zone (IB) at the bottom of the tower (1), where they are mixed with the polyol stock solution. This mixing is actively performed by operating the stirrer (19), and this mixing and stirring is continued not only while the silica gel particles continue to fall, but also after the silica gel particles have finished falling. is prevented and maintained in a uniformly dispersed state.

In this manner, a foamable urethane stock solution is obtained by mixing and stirring a predetermined amount of gas adsorbing particles and a predetermined amount of a polyol stock solution in the mixing zone (IB).

The foaming urethane stock solution is taken out through the line (16) by operating the metering pump (15) and directed to the packaging line or urethane foam production line by opening the valve (17), and the entire amount has been taken out. Later, a metering pump (15
) and the stirrer (19) are deactivated and the valve (1
8) is closed.

After the entire amount has been taken out, the tower (1) is filled with foaming gas, so by feeding the polyol stock solution and silica gel particles into the tower (1) again, the predetermined amount is again supplied. Can produce foamable urethane stock solution.

The foamable urethane stock solution produced by the production apparatus of the present invention is
Since it contains foamable gas-adsorbing silica gel particles, when these are mixed with the isocyanate stock solution, gas is desorbed from the particles due to the heat of reaction, foaming occurs, and urethane foam is obtained.

FIG. 2 shows another embodiment of the device according to the invention, in which - the stirrer (19), in addition to the stirring blades (21), the adsorption zone (IA
) There is no substantial difference from the previous embodiment except for the provision of a spiral blade (22) for generating a vortex flow.

In this example, since a vortex is formed in the adsorption zone (IA), the silica gel particles rotate and fall under their own weight in the adsorption zone (IA), reducing the contact time with the foaming gas. It is possible to increase the length of time and therefore the amount of adsorption.

In FIG. 2, (a) shows the mixing head of the urethane foam manufacturing equipment, and in the head (a), the foamable urethane stock solution from the manufacturing equipment of the present invention and the isocyanate stock solution from the liquid tank (b) are mixed. Urethane foam can be obtained by mixing it with various known additives.

If the supply of the foamable urethane stock solution to the mixing head (a) is intermittent, a pipe branched off from the discharge pipe (16) is used to prevent settling of the silica gel particles and thus non-uniform dispersion during the supply stop. Using the reflux tube (18),
It is preferable to circulate the foamable urethane stock solution, and during circulation, a three-way valve (17a) also provided at the branch point is opened to the reflux pipe (18) side.

The mixing ratio of each component of the foamable urethane stock solution obtained by the production apparatus of the present invention is specifically shown below.

(Example 1) Polyol stock solution 100 parts by weight Silica gel particles 65.0 parts by weight (75μ) Monochlorodifluoromethane 11.6 parts by weight [Example 2] Polyol stock solution 100 parts by weight Silica gel particles 65.7 parts by weight (75μ) Difluoroethane 11.6 Parts by weight [Example 3] Polyol stock solution 100 parts by weight Silica gel particles 76.7 parts by weight (75μ) Monochlorodifluoromethane 21.4 parts by weight [Example 4] Polyol stock solution 100 parts by weight Silica gel particles 60.8 parts by weight (75μ) Difluoroethane 10 .1 multiple world examples 1 to 4
An example of the specific gravity and thermal conductivity of a urethane foam obtained by mixing a foamable urethane stock solution and an isocyanate stock solution together with various known additives is as follows.

Specific gravity Thermal conductivity Ct/cd> (Kcd/m・Hr・℃) Example 1
0.062 0.0156 Example 2 0.062
0.0174 Example 3 0.068 0.0200 Example 4 0.058 0.0207 Effect The foamable polyurethane stock solution produced by the production apparatus of the present invention has no risk of depleting the atmospheric ozone layer, and is liquid at room temperature. Urethane foam can be manufactured using the same simple manufacturing equipment and operations as when using a blowing agent, and the use of such a stock solution improves air quality, urethane foam manufacturing equipment, simplification of operations, and the foam manufacturing work environment. Daily goals such as improvement can be achieved all at once.

Further, in the present invention, since the structure is such that adsorption operation can be performed in the upper part of the tower and mixing operation can be performed in the lower part, the production of foamable urethane stock solution can be easily achieved in terms of equipment and operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a schematic explanatory diagram showing another embodiment of the present invention.

In the figure, (1) is the adsorption mixing column, (2) is the exhaust line,
(3) is a vacuum bomb, (4) is a valve, (5) is a pressure tank, (6) is a gas supply line, (7) is a regulator, (8) is a valve, (9) is a powder tank, (10) is a ) is the powder supply line, (11) is the powder valve, (12) is the liquid tank, (13) is the metering pump, (14) is the liquid supply line, (15) is the metering bomb, and (16) is the discharge line. ,
(17) is a valve.

Claims (1)

[Claims] (1) Equipped with a supply section for a foaming gas that is a gas at room temperature, a supply section for silica gel particles, a supply section for a polyol stock solution, and an adsorption mixing column that receives the supply of the foaming gas, silica gel particles, and polyol stock solution from each of the above-mentioned supply sections. The adsorption mixing tower is equipped with an adsorption zone at the top where the silica gel particles contact and adsorb the foaming gas while falling into the tower, and a mixing zone at the bottom where the foaming gas-adsorbing silica gel particles and the polyol stock solution are mixed. An apparatus for manufacturing a foamable urethane stock solution, which is characterized by: