JP3292261B2 - Gas mixing method to highly viscous liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas mixing method for injecting a pressurized gas into a highly viscous liquid so as to be uniformly dispersed.

[0002]

2. Description of the Related Art In the case of producing a foam while mixing and reacting a high-viscosity liquid base material and a curing agent to generate a reaction gas, it is necessary to mix a small amount of an inert gas with the base material before the reaction in advance. It has been proposed by the applicant of the present application in the prior application that the rapid growth of bubbles due to the reaction gas can be suppressed and the foam can be made into a foam having a high foaming rate in which the bubbles are uniformly dispersed. (Japanese Patent Application No. 3-19001
No. 0).

According to studies made by the present inventors, in order to produce such a foam having a high foaming rate which is uniformly dispersed, it is necessary to disperse an inert gas which is previously mixed in a small amount with a viscous liquid as described above. It has been found that the higher the is, the more the cell dispersibility of the foam after curing can be improved. Conventionally, a method of mixing a pressurized gas with a highly viscous liquid is known in the production of whipped cream and urethane foam. However, when a pressurized gas is mixed with a highly viscous liquid, there is a problem that uniform mixing is extremely difficult as shown in FIG.

That is, as shown in FIG. 6A, for a high-viscosity liquid supplied at a flow rate Q,
When mixing relatively large flow rate q ₁ of the pressurized gas as shown in (B), there is a phenomenon that the injection start to the pressurized gas to overshoot mixed excessively, and as the (C) when mixing pressurized gas low flow q ₂ are mixed together from the start of injection to high viscous liquid is delayed, there is a phenomenon that also overshoot. For this reason, the foam at the beginning of the injection of the pressurized gas has a nonuniform foam dispersibility and foaming rate, and at least the foam in the initial portion has to be discarded.

[0005] Due to such a phenomenon, a fatal drawback is caused particularly when a high-viscosity liquid and a pressurized gas are intermittently supplied to produce a foam in a batch system. That is, as shown in FIG. 7A, when the high-viscosity liquid is intermittently supplied by alternately performing the supply time T ₁ and the stop time T _2, and injecting and mixing the pressurized gas in synchronization with the supply time T ₁ , injection of the pressurized gas results in a highly viscous lag time T ₃ from the supply of the liquid as shown in FIG. 7 (B), the and for causing significant overshoot, it is almost impossible to obtain a uniform product Become.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas mixing method capable of uniformly dispersing a pressurized gas in a highly viscous liquid.

[0007]

In order to achieve the above object, according to the present invention, a high viscosity liquid supply pipe and a pressurized gas supply pipe are connected to a mixing chamber, and the high viscosity liquid supplied from the high viscosity liquid supply pipe is supplied to the mixing chamber. When injecting the pressurized gas from the pressurized gas supply pipe, a valve mechanism for alternately opening and closing the intake side and the exhaust side is provided upstream of the pressurized gas supply pipe, and the pressurized gas is alternately opened and closed by the valve mechanism. The pulse is intermittently injected into the high-viscosity liquid, and the pulse interval of the pressurized gas is controlled so as to be proportional to the flow rate of the high-viscosity liquid in the high-viscosity liquid supply pipe. is there.

In another method according to the present invention, a high-viscosity liquid supply pipe and a pressurized gas supply pipe are connected to a mixing chamber, and the high-viscosity liquid supplied from the high-viscosity liquid supply pipe is connected to the pressurized gas supply pipe. When a pressurized gas is injected from the above, a valve mechanism that alternately opens and closes an intake side and an exhaust side is provided upstream of the pressurized gas supply pipe, and the pressurized gas is intermittently intermittently opened and closed by alternately opening and closing the valve mechanism. The high-viscosity liquid is injected into the high-viscosity liquid, and a variable capacity tank is interposed between the intake side and the exhaust side, and the volume of the tank is controlled so as to be proportional to the flow rate of the high-viscosity liquid in the high-viscosity liquid supply pipe. It is characterized by doing.

As described above, by injecting the pressurized gas into the high-viscosity liquid by intermittently intermittently supplying the high-viscosity liquid, the high-viscosity liquid can be mixed without causing a time lag or overshooting. In addition, since the injection amount is made to be proportional to the flow rate of the high-viscosity liquid, it can be uniformly dispersed and mixed. In the method of injecting the pressurized gas according to the present invention, the viscosity of the highly viscous liquid is 1,000
Centipoise or more, more preferably 3,000 to 50
It is more effective in the case of 000 centipoise. In addition, it is more advantageous when the mixing ratio of the pressurized gas is in the range of 0.5 to 50 Ncc per 100 g of the highly viscous liquid.
It is good to make it 20 Ncc / min.

Further, by providing a stirring means in the mixing chamber and injecting a pressurized gas while stirring the highly viscous liquid by the stirring means, it is possible to obtain even higher uniform dispersibility and to use the apparatus. The size can be reduced. The stirring means may be a dynamic means using a stirring blade or a static means such as a static mixer.

The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 shows a row of apparatuses for carrying out the method of mixing a gas into a highly viscous liquid according to the present invention. More specifically, a large number of dust covers D are fed out one by one, and a foam is sequentially placed on the upper edge thereof. The case of an apparatus for applying and forming a gasket E is shown. 1 is a mixing tank, 2 is a tank storing a main agent A of a high-viscosity liquid, 3 is a tank storing a hardening agent B of a high-viscosity liquid, and 4 is a flow control unit of the pressurized gas C. The mixing tank 1 has a bottom connected to a discharge nozzle 22 via a flexible tube 21, and the discharge nozzle 22 is rotated around the upper edge of the dust cover D by a robot (not shown), so that the inside of the mixing chamber 1 a is formed. A foam gasket E is formed by discharging and applying a highly viscous liquid in a bead shape, and this operation is performed while sequentially replacing a new dust cover D. Therefore,
High viscosity liquid is intermittently discharged (supplied) from the mixing tank 1,
The discharge and the stop are repeated.

A stirrer 5 is provided in the mixing chamber 1a, and the stirrer 5 is driven by a motor 6. Liquid pumps 7 and 8 are provided below tanks 2 and 3, respectively, and connected to the upper part of mixing chamber 1a via high-viscosity liquid supply pipes 9 and 10 via check valves 11 and 12, respectively. I have. When the high-viscosity liquid is discharged from the discharge nozzle 22, the non-return valves 11 and 12 serve to supply the high-viscosity liquid supply pipes 9 and 10.
When the high-viscosity liquid is introduced into the mixing chamber 1a and the discharge of the discharge nozzle 22 is stopped, the introduction is stopped.

On the other hand, the pressurized gas supply pipe 13 is connected to the mixing chamber 1a.
Is connected via a check valve 14, and an injection amount control unit 4 is provided upstream of the check valve 14. The injection amount control unit 4 is provided with on-off valves 15 and 16 on the intake side and the exhaust side, respectively, and a tank 17 is provided between the on-off valves 15 and 16. On-off valves 15 and 16
Opening and closing are alternately performed at a predetermined frequency in response to a signal from the control unit 18, and the opening and closing operations are in an opposite relationship to each other. That is, when the on-off valve 15 is open, the on-off valve 16 is closed and a certain amount of pressurized gas C is temporarily stored in the tank 17, and then stored in the tank 17 by closing the on-off valve 15 and opening the on-off valve 16. The pressurized gas C is discharged. Since this operation is performed at a predetermined frequency, the pressurized gas is intermittently discharged from the on-off valve 16 on the exhaust side in a pulsed manner, and the high-viscosity liquid in the mixing chamber 1 a is pulsed one by one through the check valve 14. Is injected into.

As described above, the structure of the pair of on-off valves 15 and 16 for pulsating the pressurized gas and the tank 17 may be constituted by combining individual parts as shown in the illustrated example. You may make it comprise by a three-way valve. Control unit 18
Inputs a signal of the flow rate Q of the high-viscosity liquid (base agent A) from the flow meter 19 provided in the high-viscosity liquid supply pipe 9 and inputs a preset mixing ratio r. And instructs the on-off valves 15 and 16 to alternately open and close at pulse intervals such that the injection amount q is obtained.

Therefore, when the high-viscosity liquid is intermittently supplied to the mixing chamber 1a while changing the flow rate to Q ₁ and Q ₂ as shown in FIG. Is intermittently injected as a pulse as shown in FIG. That is, when the flow rate of the high-viscosity fluid is Q _1, pressurized gas is injected interval T _3, but is injected at pulse interval of interruption interval T _4, than Q ₁ as the flow rate of the high viscous fluid Q ₂ If less, the pulse of pressurized gas is injected interval while the shorter T ₅ than T _3, is adapted to the interruption interval longer T ₆ than T _4.

As described above, since the pressurized gas is injected into the high-viscosity liquid instantaneously in a pulsed manner, there is no time lag or overshoot from the time of supply of the high-viscosity liquid, and the injection is not performed. Since the amount is proportional to the flow rate of the highly viscous liquid, it can be uniformly dispersed. As described above, the check valve 14 of the injection section for injecting the pressurized gas C into the highly viscous fluid at a constant rate may have a structure as shown in FIG. That is, the valve body 23 of the check valve 14 is urged toward the pressurized gas supply pipe 13 side, and the valve seat 23a is provided so as to open to the wall surface side of the mixing chamber 1a. Then, as shown by the dashed line, it enters and exits the mixing chamber 1a side.

With such a valve configuration, the pressurized gas C supplied from the pressurized gas supply pipe 13 does not stay inside the check valve 14, and is smoothly discharged into the high-viscosity liquid in the mixing chamber 1a. be able to. Thus, it further improves the dispersibility of the pressurized gas. FIG. 3 shows another embodiment of the present invention. In this embodiment, the fixed-capacity tank 17 provided between the pair of on-off valves 15 and 16 in the above-described embodiment of FIG. 1 is replaced with a cylinder-piston type variable-capacity tank 17 '. In addition, the volume of the variable capacity tank 17 'is made to be proportional to the flow rate Q of the high-viscosity liquid in the high-viscosity liquid supply pipe 9.

That is, in the embodiment shown in FIG.
Although the injection amount of the pressurized gas is set by changing the pulse interval of the alternate opening and closing of the open / close valves 5 and 16, in this embodiment, the pulse interval of the alternate opening and closing of the open / close valves 15 and 16 is fixed, and the volume of the variable capacity tank 17 'is changed. Is changed by the control unit 18 in proportion to the preset mixing ratio r ′ according to the flow rate Q of the high-viscosity liquid in the high-viscosity liquid supply pipe 9.

This embodiment is the same as FIG. 1 in that the pressurized gas is injected in a pulsed manner, but the injection method is different. That is, as shown in FIG.
For a highly viscous liquid that is intermittently supplied to the mixing chamber 1a at different flow rates Q ₁ and Q ₂ , the injection amount of the pressurized gas per pulse is changed as k ₁ and k ₂ , respectively. ing. Also in this method, the pressurized gas can be uniformly dispersed and mixed in the highly viscous liquid.

FIG. 4 shows still another embodiment of the present invention. In the figure, only the main part is shown. In the embodiment of FIG. 1 described above, a pressure regulating valve 25 is provided upstream of the on-off valves 15 and 16 on the pressurized gas supply pipe 13 side, and a pressure gauge is provided on the high viscosity liquid supply pipe 9 side. 26 are provided. In this embodiment, the supply pressure P of the high-viscosity liquid in the high-viscosity liquid supply pipe 9
Is detected by the pressure gauge 26, and the pressure regulating valve 25 is set in proportion to the supply pressure P in proportion to a predetermined mixing ratio r ″.
The supply pressure of the pressurized gas on the side of the pressurized gas supply pipe 13 is adjusted by adjusting the opening degree. By adjusting the pressure of the pressurized gas, the injection amount of the pressurized gas can be balanced with the pressure of the highly viscous liquid, and can be uniformly mixed by a pulsed injection operation as shown in FIG.

In the present invention, the above-mentioned uniform dispersion of the pressurized gas is more effective when applied to a highly viscous liquid having a viscosity of 1,000 centipoise or more, more preferably 3,000 to 500,000 centipoise. . Also,
If the injection amount of the pressurized gas at this time is controlled to a mixing ratio in the range of 0.5 to 50 Ncc with respect to 100 g of the highly viscous liquid, a finer dispersed state can be obtained. Also,
At this time, the flow rate of the pressurized fluid is 0.02 to 20 N
A range of cc / min is desirable.

In the present invention, the type of the highly viscous liquid is not particularly limited, but is particularly effective when producing a silicone rubber foam which cures while generating a gas by a condensation reaction. As a material for forming such a silicone rubber foam, an organopolysiloxane having two or more silanol groups in one molecule, for example, a diorganopolysiloxane having silanol groups blocked at both ends is mainly used.
An organohydrogenpolysiloxane containing three or more silicon-bonded hydrogen atoms in the molecule as a curing agent,
It is preferable to use a curing catalyst using a condensation reaction promoting catalyst such as a platinum compound or an organotin compound. This material cures while generating hydrogen gas to form a silicone rubber foam.

In this case, a diorganopolysiloxane having silanol groups blocked at both ends and a platinum compound catalyst are used as main components,
A diorganopolysiloxane blocked with silanol groups at both ends and an organohydrogenpolysiloxane having three or more silicon-bonded hydrogen atoms in one molecule are used as a curing agent, and the volume ratio of the main agent and the curing agent is approximately 1: 1. Are preferred.

Another example of a foam is a flexible or rigid polyurethane foam. These use diisocyanate or polyisocyanate as a main component, and use a mixture of a polyol and water as a curing agent. Further, the pressurized gas used in the present invention is not particularly limited,
For example, an inert gas such as air, nitrogen, helium, argon, and carbon dioxide can be used. Among them, air that is easy to handle is particularly preferable.

[0025]

As described above, according to the method for mixing a gas with a high-viscosity liquid according to the present invention, the pressurized gas is intermittently injected in a pulsed manner and injected into the high-viscosity liquid. Mixing is possible without causing a time lag or overshooting with respect to the supply timing of the liquid, and the injection amount is made proportional to the flow rate of the highly viscous liquid, so that the liquid can be uniformly dispersed and mixed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus for performing a method of mixing a gas into a highly viscous liquid according to the present invention.

FIG. 2 is a schematic view showing an example of a check valve used in a pressurized gas injection section of the apparatus of FIG.

FIG. 3 is a schematic view showing another example of an apparatus for performing the method of mixing a gas into a highly viscous liquid according to the present invention.

FIG. 4 is a schematic view showing another example of an apparatus for carrying out the method of mixing a gas into a highly viscous liquid according to the present invention, showing only main parts.

FIGS. 5A, 5B, and 5C are graphs showing changes in flow rates of a highly viscous liquid and a pressurized gas when intermittently supplied according to the present invention.

FIGS. 6A, 6B, and 6C are graphs showing changes in flow rates of a highly viscous liquid and a pressurized gas when continuously supplied by a conventional method.

FIGS. 7A and 7B are graphs showing changes in flow rates of a highly viscous liquid and a pressurized gas when intermittently supplied by a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Mixing tank 1a Mixing chamber 2, 3 Tank 4 Injection amount control part 5 Stirrer 9 High viscous liquid supply pipe 13 Pressurized gas supply pipe 14 Check valve 15, 16 Open / close valve (valve mechanism) 17 Tank 17 'Variable capacity tank 18 Control unit 19 Flow meter 25 Pressure regulator 26 Pressure gauge

Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29K 75:00 B29K 75:00 (72) Inventor Takehiro Watanabe 2-2 Chigusa Beach, Ichihara-shi, Chiba Dow Corning Silicone Co., Ltd. Research (56) References JP-A-63-143932 (JP, A) JP-A-64-58337 (JP, A) JP-A-60-201917 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B01F 15/04 B01F 3/04 B29B 7/80 B29C 67/20 C08J 9/30 B29K 75:00

Claims (6)

(57) [Claims] 1. A high-viscosity liquid supply pipe and a pressurized gas supply pipe are connected to a mixing chamber, and a pressurized gas is injected from the pressurized gas supply pipe into the high-viscosity liquid supplied from the high-viscosity liquid supply pipe. A valve mechanism for alternately opening and closing the intake side and the exhaust side is provided upstream of the pressurized gas supply pipe, and the alternately opening and closing of the valve mechanism causes the pressurized gas to be intermittently intermittently injected into the highly viscous liquid. And a method of mixing a gas into a high-viscosity liquid, wherein a pulse interval of the pressurized gas is controlled so as to be proportional to a flow rate of the high-viscosity liquid in the high-viscosity liquid supply pipe. 2. A high-viscosity liquid supply pipe and a pressurized gas supply pipe are connected to a mixing chamber, and a pressurized gas is injected from the pressurized gas supply pipe into the high-viscosity liquid supplied from the high-viscosity liquid supply pipe. A valve mechanism for alternately opening and closing the intake side and the exhaust side is provided upstream of the pressurized gas supply pipe, and the alternately opening and closing of the valve mechanism causes the pressurized gas to be intermittently intermittently injected into the highly viscous liquid. And a variable capacity tank is interposed between the intake side and the exhaust side, and gas mixing with the high-viscosity liquid is performed so as to control the tank volume in proportion to the flow rate of the high-viscosity liquid in the high-viscosity liquid supply pipe. Method. 3. A high-viscosity liquid supply pipe and a pressurized gas supply pipe are connected to a mixing chamber, and a pressurized gas is injected from the pressurized gas supply pipe into the high-viscosity liquid supplied from the high-viscosity liquid supply pipe. A valve mechanism for alternately opening and closing the intake side and the exhaust side is provided upstream of the pressurized gas supply pipe, and the alternately opening and closing of the valve mechanism causes the pressurized gas to be intermittently intermittently injected into the highly viscous liquid. And a method of mixing the gas with the high-viscosity liquid, wherein the supply pressure of the pressurized gas is controlled so as to be proportional to the supply pressure of the high-viscosity liquid in the high-viscosity liquid supply pipe. 4. The high-viscosity liquid has a viscosity of 1,000 centipoise or more, and a mixing ratio of the pressurized gas to 100 g of the high-viscosity liquid is in a range of 0.5 to 50 Ncc. The method for mixing a gas with a highly viscous liquid according to claim 3. 5. The method according to claim 4, wherein the flow rate of the pressurized gas in the pressurized gas supply pipe is set to 0.02 to 20 Ncc / min. 6. The high-viscosity liquid according to claim 1, wherein a stirring means is provided in the mixing chamber, and a pressurized gas is injected into the high-viscosity liquid stirred by the stirring means. Gas mixing method.