JP3066093B2 - Method for producing polyvinyl butyral resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyvinyl butyral resin, and more particularly to a method for producing a polyvinyl butyral resin in which a scale is prevented from adhering to an apparatus in a precipitation method in which a butyralization reaction is performed at a relatively high temperature.

[0002]

2. Description of the Related Art Polyvinyl butyral resin is used as a raw material for an interlayer film used for a windshield of an automobile, a resin for an adhesive, a resin for a paint, and various binder resins. The law has been industrialized.

In the case of producing a polyvinyl butyral resin by a precipitation method, a polyvinyl alcohol solution is cooled to a relatively low temperature (0 to 20 ° C.) to obtain uniform particles, and a butyralization reaction is carried out. Easily occur, and the obtained resin is partially insoluble in the solvent,
There are problems such as an increase in the melt viscosity of the resin. By the way, when a polyvinyl butyral resin is used, for example, as an intermediate film of a windshield of an automobile, a resin having a low melt viscosity is desired. That is, the adhesion between the interlayer film and the glass is 130 to 150 ° C., and the pressure is 10 to 15 kg / cm ^2.
Is performed in an autoclave under the following conditions. However, since laminated glass having a large bending is used in recent years, when the interlayer film is not sufficiently flown at the time of bonding in the autoclave, defects such as foaming occur. Therefore, it is important to lower the melt viscosity of the resin at around 130 to 150 ° C.

[0004] In order to solve these problems, there has been proposed a method in which a butyralization reaction is carried out at a relatively high temperature (50 to 100 ° C) where gelation of polyvinyl alcohol does not easily occur in the precipitation method (US Pat. No. 2,702,501). However, if performing the butyralization reaction at elevated temperature according to this method,
Scale adhered to the inner wall, etc. of the reaction apparatus, or becomes impossible operation with driving long device that deposits from the inner wall quality defects occur such that foreign matter is mixed into the resin by dropping There was a problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a resin having improved solvent solubility and reduced melt viscosity. Another object of the present invention is to provide a method for producing a polyvinyl butyral resin which can prevent scale from adhering to an inner wall of a reactor.

[0006]

The polyvinyl butyral resin has different properties depending on the degree of butyralization. The polyvinyl butyral resin synthesized by the precipitation method has a butyralization degree of 20.
Although it is insoluble in water at about mol%, the formation of particles is incomplete gelation up to a degree of butyralization of 40 mol%, the adhesiveness is strong, and it easily adheres as a scale to the inner wall of the reactor, the inside of piping, etc. It has been found. For this reason, in the synthesis reaction of polyvinyl butyral resin having a butyralization degree of up to 40 mol%, the reaction is carried out under the conditions of the following materials and flow rates to prevent scale adhesion. In the case of synthesizing a polyvinyl butyral resin, the butyralization degree has a distribution, and the measured butyralization degree of the resin is an average value of the butyralization degree having the distribution. For example, polyvinyl butyral resins having a butyralization degree of 40 mol% or more include those having a butyralization degree of less than 40 mol%. In the present invention, the degree of butyralization is measured as follows. The sample was washed with water in a conventional manner, neutralized and dried, and then subjected to JISK-67.
The butyralization degree was measured according to the method for measuring the butyralization degree of No. 28.

[0007]

[0008]

The method for producing a polyvinyl butyral resin of the present invention comprises reacting a polyvinyl alcohol dissolving tank, a butyraldehyde tank, a polyvinyl alcohol solution supplied from the polyvinyl alcohol dissolving tank, and butyraldehyde supplied from the butyraldehyde tank. Let
First loop reactor and second loop reactor and mature
A reactor comprising a Naruso, using a manufacturing apparatus having a met method for producing a polyvinyl butyral resin
Te, butyralization degree of up to at least 40 mol% reaction first performed in a loop reactor and the following (A) ~ (C)
And the butyralization degree is at least 40
Up to 55 mol% in a second loop reactor
The reaction is performed under the condition that the flow rate of the liquid during the reaction is 2 m / sec or more, thereby achieving the above object.

(A) The liquid-contact part of the reactor is made of glass, and (B) the surface roughness Rz of the liquid-contact part of the reactor is 0.5 μm or less (provided that the surface roughness Rz is (C) The flow velocity of the liquid at the time of the reaction is 5 m / sec or more, which is the average roughness of 10 measured values measured using a stylus type roughness measuring instrument in accordance with the measurement of ISO R468.

The apparatus for producing a polyvinyl butyral resin used in the present invention comprises at least a polyvinyl alcohol dissolving tank, a butyl aldehyde tank, a polyvinyl alcohol solution supplied from the polyvinyl alcohol dissolving tank, and butyl aldehyde supplied from the butyl aldehyde tank. First loop reactor and second loop to react
A reactor comprising a reactor and an aging tank .

In the present invention, a first loop reactor in which a liquid contact portion of a reaction device in contact with a reaction solution having a degree of butyralization of at least up to 40 mol% is made of glass is used. is there. Butyral degree of at least 4
Second loop rear contacted with a reaction solution of 0 to 55 mol%
The liquid contact part of the reactor may be glass or various materials such as metal and plastic. In order to form the portion in contact with the reaction solution with glass, for example, the inner surface of the reaction device may be lined with glass, or a device made of glass may be used. Examples of the glass include soda-lime glass, potash glass, lead glass, borosilicate glass, quartz glass, and enamel.

The reason is considered as follows.

A conventionally known degree of butyralization of 40 mol%
Examination of the adhesiveness of the reaction solution to various materials such as metal, glass, and plastic revealed that a material having a smaller contact angle with water (that is, a material that is more easily wetted with water) is less likely to adhere. As a result of confirming the adhesion of the reaction solution using glass having a contact angle with water of 7 °, it was found that the reaction solution hardly adhered to the glass. In the method for producing a polyvinyl butyral resin in the precipitation method as in the present invention, since the reaction solution uses water as a medium, an aqueous layer formed on the surface of the material due to the surface of the material being wetted with water has a resin adhesion. It is supposed that it is preventing.

First loop reactor used in the present invention
The surface roughness of the liquid - contact part of-is 0.5
(However, the surface roughness Rz is measured using a stylus-type roughness meter in accordance with the measurement of ISO R468, and is the average roughness of 10 measured values), preferably Is 0.3 or less. In order to make the surface roughness of the liquid contact portion be in the above range, for example, a polishing apparatus may be used. The reason is as follows.

When the same material was used and the smoothness of the surface was changed to examine the adhesion of the resin, it was found that the smoother the surface of the liquid contact portion, the harder the resin was to adhere. This is presumed to be due to a difference in the anchor effect when the resin adheres to the liquid contact part.

In the present invention, the flow rate of the reaction solution having a butyralization degree of at least up to 40 mol% is 5 m / sec or more. The reason is as follows.

Whether or not the scale adheres to the inner wall of the apparatus is determined as follows.
It is determined by the relationship between the adhesive force of the resin to the inner wall of the device and the flow rate of the liquid, which is the force that causes the attached scale to separate from the inner wall of the composition.For example, if the peeling force of the scale is stronger than the adhesive force The resin does not adhere to the device.
Therefore, the adhesion of the scale to the apparatus was examined by changing the flow rate of the liquid during the reaction. If the flow rate of the reaction liquid was 5 m / sec or more, preferably 6 m / sec or more, the scale did not adhere to the inner wall of the apparatus. I understood. A pump is used to increase the flow rate of the reaction solution to 5 m / sec or more .

Further, in the present invention , the adhesion of scale can be further prevented by synthesizing the polyvinyl butyral resin under the following conditions. That is, the reaction up to a butyralization degree of 60 mol% or more,
A first having a degree of butyralization of at least 40 mol% ;
A reaction in a loop reactor, a reaction in a second loop reactor having a butyralization degree of 40 mol% to 55 mol%, and a reaction in an aging tank having a butyralization degree of 55 mol% or more, In the above reaction, the above-mentioned conditions, that is, the liquid contact portion of the apparatus was formed of smooth glass having a surface roughness of 0.5 μm or less, the flow rate of the reaction solution was 5 m / sec or more, At a flow rate of 2 m / sec or more. The reason is as follows.

As a method for preventing the clogging of the resin in the pipe and the adhesion of the scale to the apparatus, the present inventors conducted the reaction at a butyralization degree of at least 40 mol% at a high flow rate as described above. We have found a way to carry out the reaction in an apparatus made of glass, which is a smooth material whose wetted part is easily wetted by water, but found the following problems.

(1) A reaction solution having a butyralization degree of about 40 mol% is charged into a tank used for ordinary chemical reaction (hereinafter referred to as an aging tank), and a butyralization degree of 65 used as a normal butyral resin is obtained. When the reaction proceeds to about mol%, the reaction solution is charged even when the peripheral speed during stirring is about 5 m / sec.
There is a possibility that coalescence of particles occurs instantaneously.

In the above reaction, butyralization progresses on the surface of the coalesced resin, but the reaction hardly progresses at the center of the particles. Therefore, when the reaction solution having a butyralization degree of about 40 mol% is put into the tank, as compared with the case where the reaction liquid having a butyralization degree of about 55 mol% is put into the tank when the reaction liquid is put into the tank. When the reaction temperature is about 60 to 90 ° C., the reaction time is twice as long. Also, 6
When the reaction is performed at a relatively high temperature of 0 to 90 ° C. for a long time, there is a possibility that butyraldehyde is condensed by an acid serving as a catalyst and excess butyraldehyde to cause yellowing of the resin.

(2) Butyralization degree 65 in a relatively short time
In order to advance the reaction to about mol%, it is necessary to increase the degree of butyralization entering the aging tank to about 55 mol%. Under the conditions of a reaction temperature of 60 to 90 ° C. and a catalyst concentration of 0.5% or less, when a loop reactor advantageous for preventing adhesion is used as a reaction device, a residence time in the loop reactor is required to be about 5 minutes. In order to prevent scale adhesion, the flow rate of the reaction needs to be 5 m / sec or more. However, a reactor that satisfies a residence time of 5 minutes and a liquid flow rate of 5 m / sec or more during this period is possible with experimental facilities, but is difficult in a commercial scale. For example, when the amount of the polyvinyl alcohol solution is 30 m ³ per batch, the loop reactor has a capacity of 2.1 in consideration of a loop reactor having a withdrawal time of 70 minutes and a residence time of 5 minutes.
m ^3, and when the pipe size 100, a length of about 270m
Requires a large space.

In order to obtain a flow rate of the reaction solution of 5 m / sec or more, there is also a pressure loss in the piping, so a circulation pump having a discharge pressure of 6 kg / cm ² and a discharge amount of 150 m ³ / hour is required. Pumps with smooth inner surfaces are difficult to obtain. Thus, there is a problem in obtaining a resin efficiently in a relatively large plant of about 30 m ³ .

As a solution to these problems, it is conceivable to install an auxiliary tank in the loop reactor. However, if a stirring device is provided in the tank, it is difficult to secure the flow velocity around the stirring shaft, and scale adheres. It is conceivable to prevent the coalescence of particles in the aging tank by adding a surfactant, etc. to the reaction solution, but it is difficult to remove the surfactant from the generated solution, and the quality of the residue It is not preferable because there is a concern about the adverse effect of the method.

Therefore, as described above, the butyralization degree at which the scale easily adheres is at least 40 mol% .
The reaction in the first loop reactor was carried out under the condition that the liquid contact portion used a smooth glass having a surface roughness of 0.5 μm or less to prevent scale, and the flow rate of the liquid during the reaction was 5 m / sec or more. It is important to proceed the butyralization reaction without coalescing the resin in a short time. The reaction in the second loop reactor having a butyralization degree of at least up to 40 to 55 mol% is carried out at a flow rate of 2 m. Per second / second or more while preventing coalescence of particles and proceeding in a short time, butyralization degree 55 mol%
By proceeding with the normal reaction method using the aging tank , the scale of the equipment does not adhere to the equipment. You get it.

According to this method, as described above, the solvent solubility is improved and the melt viscosity is reduced (resin 100
A resin synthesized by mixing 40 parts by weight of a plasticizer with a part by weight, forming a sheet by pressing, and dissolving at 140 ° C. at a relatively low temperature as measured by a Koka type flow tester is about 15 × 10 ⁴ poises. The resin synthesized at 60-90 ° C is 7 ×
10 ⁴ decreases to about poise) resin, it can be relatively obtained at high temperatures.

The reaction rate in the first loop reactor is affected by the reaction temperature, the concentration of the catalyst, the concentration of butyraldehyde in the reaction solution, and the like.
It was confirmed that the average residence time required to advance to a degree of butyralization of 40 mol% under conditions of 0 ° C and a catalyst concentration of 0.5% or less was within 1 minute. Therefore, an area requiring a high flow rate and a smooth material that easily wets with water in order to prevent scale adhesion is one minute from the beginning of the reaction, and an efficient process can be performed even on a commercial scale.

When a reaction solution having a butyralization degree of about 40 mol% is replaced with a reactor having a relatively low flow rate and low stirring,
Coalescence of the particles occurs, so that butyraldehyde and the catalyst are not sufficiently supplied to the center of the particles, so that the reaction rate thereafter is reduced. In addition, there are problems such as a difference in the degree of butyralization between the central part and the surface. Therefore, the subsequent reactions also need to proceed under relatively strong agitation.

The reaction in the second loop reactor having a butyralization degree of 40 to 55 mol% was also studied. As a result, if the flow rate of the reaction solution was 2 m / sec or more, the reaction temperature was 60 to 90 mol%.
C., the catalyst temperature was 0.5% or less, and the coalescence of the particles was small by staying for 5 minutes, confirming that the reaction proceeded.
Regarding the material of the liquid contact portion, when a tank or the like is used, a glass that is easily wetted by water is preferable because the flow velocity of the shaft portion may be reduced.

In an aging tank having a butyralization degree of 55 mol% or more
The reaction may be a commonly used tank type .

[0032]

The synthesis reaction of a polyvinyl butyral resin having a degree of butyralization of up to 40 mol% is carried out under the above conditions.
Even if the butyralization reaction is performed at a relatively high temperature (60 to 90 ° C.), it is possible to prevent the scale from adhering to the apparatus. It can be manufactured without the scale adhering to the inner wall. Moreover, as a reaction apparatus, for example, because it uses a loop reactor over the reaction liquid is circulated over a predetermined speed by a circulation pump, with that the productivity is reduced can be prevented as much as possible, the installation space of the equipment is particularly wide Nor.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

Comparative Example 1 Using the apparatus shown in FIG. 1, a polyvinyl butyral resin was synthesized according to the following reaction procedures (1) to (11).

The apparatus shown in FIG. 1 comprises a polyvinyl alcohol dissolving tank 1, one loop reactor 10, and an aging tank 2
And a butyraldehyde tank 3. The polyvinyl alcohol dissolving tank 1 and the loop reactor 10 are connected by a supply pipe 4, the loop reactor 10 and the aging tank 2 are connected by a transfer pipe 5, and the loop reactor 10
And butyraldehyde tank 3 are connected by a supply pipe 6. The loop reactor 10 is provided with a circulation pump 7, a pressure gauge 8, and a flow meter 9, and the supply pipes 4, 6 are provided with pumps 14, 16, respectively.

The polyvinyl alcohol dissolving tank 1 is made of stainless steel having a capacity of 100 liters, and the loop reactor 10 is as follows. The aging tank 2 is made of a glass lining material having a capacity of 100 liters, and the butyraldehyde tank 3 is made of stainless steel having a capacity of 10 liters.

Then, polyvinyl alcohol and butyl aldehyde are supplied from the polyvinyl alcohol dissolving tank 1 and the butyl aldehyde tank 3 through the supply pipes 4 and 6 into the loop reactor 10, where the reaction is carried out until a predetermined degree of butyralization is reached. The reaction liquid which has reached a predetermined degree of butyralization is supplied to the aging tank 2. The supply amounts of polyvinyl alcohol and butyraldehyde are adjusted by the strokes of the plungers of the input pumps 14 and 16 provided in the respective supply pipes 4 and 6, and the flow rate of the reaction solution in the loop reactor 10 is controlled by an inverter type. It is adjusted by changing the rotation speed of the circulation pump 7. Further, an extraction valve 17 is prepared so that the pressure gauge 8 provided in the loop reactor 10 becomes constant.

(1) In a dissolution tank 1 having a capacity of 100 liters,
After 64 liters of pure water and 7.5 kg of polyvinyl alcohol were added and dispersed, the liquid was heated to 95 ° C. and kept at 95 ° C. for 90 minutes to dissolve the polyvinyl alcohol.
Cooled to 5 ° C. Polyvinyl alcohol has a degree of polymerization of 150
The one having a saponification degree of 99.5 mol% was used.

(2) 35% as a catalyst for the butyralization reaction
560 g of hydrochloric acid was charged into the polyvinyl alcohol dissolving tank 1 cooled to 75 ° C.

(3) The loop reactor 10 was a glass lining pipe having a diameter of 40, and had a volume of 5 liters.
In addition, the glass lining piping is usually a method of inserting a glass tube into a metal tube, melting and pressing, and applying a glass after applying the glass, and a method of making the glass tube only by applying and firing the glass. In the insertion method, unevenness is easily generated at the connection portion at the end, and scale is easily attached, so that it is difficult to obtain uniform smoothness. In this example, a glass lining pipe manufactured by Kobe Seiko Pantech Co., Ltd., which was created by applying and firing glass was used. Connect the flange connection so that there is no step,
The bent portion was a 5D pipe. The glass lining pipe used had a contact angle with water of 7 ° and a surface roughness Rz of 0.3 μm.

(4) After the loop reactor 10 is filled with hot water of 75 ° C., the circulation pump 7 is operated, and the flow rate is measured by the electromagnetic flow meter 9 (ADMAC, manufactured by Yokogawa Electric Corporation) attached to the loop reactor 10. Was adjusted to 5 m / sec by adjusting the inverter setting device of the pump 7 installed for adjusting the flow velocity.

(5) 10 liters of hot water at 85 ° C. was put into the aging tank 2 having a capacity of 100 liters up to the upper mirror part, so that stirring was possible.

(6) The material of the inner surface of the aging tank 2 is desirably glass from the viewpoint of difficulty in adhering scale and the corrosion resistance of hydrochloric acid used as a catalyst, and an aging tank made of glass lining was used.

(7) The polyvinyl alcohol solution is charged into the loop reactor 10 at a rate of 1 liter / minute and butyraldehyde at 57.7 g / minute, and the extraction valve 17 is adjusted so that the pressure in the loop reactor 10 becomes 4 kg / cm ^2. The reaction was advanced while adjusting the temperature.

(8) After 15 minutes from the start of the introduction of the polyvinyl alcohol solution and butyraldehyde into the loop reactor 10, a slurry liquid was sampled from the outlet of the loop reactor 10, washed with water, cooled, and cooled at 70 ° C. for 4 minutes. After neutralizing for an hour, it was dried to obtain a powdery resin. Resin
The butyralization degree was measured according to JISk6728 butyralization degree measurement method, and as a result, it was 56 mol%.

(9) When the polyvinyl alcohol dissolving tank 1 is empty, the charging of the polyvinyl alcohol solution is terminated, and when the charging amount of butyraldehyde reaches 4120 g, the charging of butyraldehyde is terminated. To wash the loop reactor 10, 12.5 liters of hot water at 75 ° C. was supplied.

(10) After aging at 85 ° C. for 4 hours in the aging tank 2, the mixture was cooled, washed, neutralized and dried to obtain a white granular resin.
As a result of measuring the butyralization degree of this resin, 66 mol%
Met. After mixing the resulting resin 100g and plasticizer 40 g, after pressing at 0.99 ° C., was measured melt viscosity of 140 ° C. under a load of 20 kg / cm ² by a Koka type flow tester, 6.8 × 10 ⁴ Poise.

(11) After completion of the reaction, the loop reactor 10
When the scale adhesion in the aging tank 2 was confirmed, no scale adhesion was observed. However, white granular resin
Some coalescence of the particles was observed.

Comparative Example 2 A volume of 0.5 was used instead of the loop reactor 10 of Comparative Example 1.
Comparative example , except using a liter loop reactor
The butyralization reaction was carried out under the same conditions as in 1 .

Since the volume of the loop reactor was as small as 0.5 liter, the degree of butyralization of the resin at the outlet of the loop reactor was 29 mol%. After the reaction,
Scale adhesion was observed on the inner wall of the aging tank 2.

[0051] Instead of the loop reactor 10 of Comparative Example 3 Comparative Example 1, except for using stainless steel pipe was conducted butyralization reaction under the same conditions as Comparative Example 1.

The stainless pipe was electrolytically polished, had a surface roughness of 0.4 μm, and a contact angle with water of 69 °.

The degree of butyralization of the resin at the outlet of the loop reactor was 54 mol%. After the reaction was completed, the loop reactor and the aging tank 2 were inspected. As a result, a scale with a thickness of 10 to 20 μm was found on the inner wall of the pipe of the loop reactor.

Comparative Example 4 A reaction was carried out under the same conditions as in Comparative Example 1 except that the flow rate in the loop reactor 10 was changed to 4 m / sec.

The butyralization degree of the resin at the outlet of the loop reactor was 54 mol%. After completion of the reaction, the loop reactor 10 and the aging tank 2 were inspected. No scale was found to adhere to the straight portion of the pipe, but a 10 to 20 μm thick scale was added to the bent portion where the flow rate of the liquid was thought to have dropped. Adhesion was seen.

Example 1 Using the apparatus shown in FIG. 2, a polyvinyl butyral resin was synthesized according to the following reaction procedures (1) to (9).

The apparatus shown in FIG. 2 includes a polyvinyl alcohol dissolving tank 1, a first loop reactor 11, a second loop reactor 12, an aging tank 2, and a butyl aldehyde tank 3. The polyvinyl alcohol dissolving tank 1 and the first loop reactor 11 are connected by a supply pipe 24, and the first loop reactor 11 and the butyl aldehyde tank 3 are connected by a supply pipe 25. First loop reactor 11 and second loop reactor 12
And the second loop reactor 12
And the aging tank 2 are connected by a transfer pipe 18. The reference numerals of the circulating pump 8 and the like provided in this apparatus are the same as those of the apparatus used in Comparative Example 1 .

The polyvinyl alcohol dissolution tank 1 is made of stainless steel having a capacity of 100 liters, the aging tank 2 is made of a glass lining material having a capacity of 100 liters, and the butyl aldehyde tank 3 is made of a 10 liter capacity.
It is made of liter stainless steel. The configuration of the first and second loop reactors 11 and 12 is as follows.

These are constituted by glass lining tubes having a capacity of 2.5 liters. Preliminary reaction, caliber 40mm
The loop reactors each having a capacity of 2.5 liters were assembled in two stages so that the average residence time of the first and second loop reactors was 2.5 minutes with the glass lining pipe of No. 1 above. The glass lining piping used has a surface roughness of 0.3
μm. The glass lining piping of Kobe Seiko Pantech Co., Ltd. was used as in Example 1. The flange connection portion was connected so that no step was formed, and the bent portion was a 5D pipe. The glass lining pipe used had a contact angle with water of 7 ° and a surface roughness Rz (ISOR468) of 0.3 μm.

In this apparatus, a supply pipe 2 is connected from a polyvinyl alcohol dissolving tank 1 and a butyl aldehyde tank 3.
Polyvinyl alcohol and butyraldehyde are supplied into the first loop reactor 11 through 4, 25, where the reaction is carried out until a predetermined degree of butyralization is reached, and the reaction solution having reached the predetermined degree of butyralization is: It is sent to the second loop reactor 12 and a butyralization reaction is further performed. Then, the reaction solution that has reached a predetermined degree of butyralization is configured to be appropriately supplied to the aging tank 2. The other configuration is the same as that of Comparative Example 1 described above, and will not be described.

(1) In a dissolving tank 1 having a capacity of 100 liters, after dispersing 7.5 kg of polyvinyl alcohol in 64 liters of pure water, the solution was heated to 95 ° C. and kept at 95 ° C. for 90 minutes to dissolve the polyvinyl alcohol. Then, it cooled to 75 degreeC. Polyvinyl alcohol has a degree of polymerization of 1500 and a degree of fighting of 9
9.5 mol% was used.

(2) 35% as a catalyst for the butyralization reaction
560 g of hydrochloric acid was placed in dissolution tank 1 cooled to 75 ° C.

(3) First and second loop reactors 11,
After the hot water of 75 ° C. was filled in the inside 12, each of the circulation pumps 7 was operated, and the flow rate was 5 m with the electromagnetic flow meter 9 (ADMAC, Yokogawa Electric Corporation) attached to the loop reactor.
/ Sec, the inverter controller of the pump 7 installed for adjusting the flow rate was adjusted.

(4) 10 liters of hot water at 85 ° C. was put into the aging tank 2 having a capacity up to the upper mirror portion of 100 liters so that stirring was possible. About the material of the tank 2, it is difficult to adhere,
Glass lining is desirable from the viewpoint of corrosion by the hydrochloric acid of the catalyst, and a tank made of glass lining was used.

(5) First and second polyvinyl alcohol solutions at a rate of 1 liter / minute and butyraldehyde at a rate of 57.5 g / minute.
The reactor was charged into the loop reactors 11 and 12, and the reaction was advanced while adjusting the extraction valve 17 so that the pressure inside the second loop reactor 12 became 2 kg / cm ² .

(6) After 15 minutes from the start of the introduction of the polyvinyl alcohol solution and butyraldehyde, the slurry liquid was sampled from the first loop reactor 11 and the second loop reactor 12, washed, cooled, neutralized at 70 ° C. for 4 hours, and dried. Thus, a powdery resin was obtained.

As a result of measuring the butyralization degree of the obtained resin according to the method of measuring the butyralization degree of JISK-6728, the first resin was obtained.
The outlet of the loop reactor 11 is 47 mol%, the second
The outlet at the loop reactor 12 was 57 mol%.

(7) When the polyvinyl alcohol solution tank 1 is empty, the introduction of the polyvinyl alcohol solution is terminated when the amount of butyraldehyde becomes 4120 g, and the introduction of butyraldehyde is terminated. For washing, 12.5 liters of 75 ° C. hot water was supplied.

(8) After aging at 85 ° C. for 1 hour in the aging tank 2, it was cooled, washed, neutralized and dried, and then white granules were formed.
A resin was obtained. The butyralization degree of the obtained resin was measured and found to be 66 mol%. Also, after mixing 100 g of this resin and 40 g of plasticizer, pressing at 150 ° C., and applying 14 kg under a load of 20 kg / cm ² with a Koka type flow tester.
The measured melt viscosity at 0 ° C. was 6.5 × 10 ⁴ poise.

(9) After the completion of the reaction, the scale adhesion in the first and second loop reactors 1112 and the aging tank 2 was confirmed. As a result, no scale adhesion was observed. Also, white granules
No coalescence of the particles was observed in the resin in the shape of a circle.

Example 2 Using the apparatus shown in FIG. 3, a polyvinyl butyral resin was synthesized according to the following reaction operations (1) to (4).

This apparatus is the same as that of the first embodiment except that the first loop reactor 11 and the second loop reactor 12 have the following configurations.

The first loop reactor 11 was formed of a glass-lined pipe having a diameter of 40, and was assembled to have a capacity of 1 liter so that the average residence time of the first loop reactor 11 was about 1 minute. The surface roughness of the used glass lining pipe was 0.3 μm.

The second loop reactor 12 was formed of stainless steel pipe having a diameter of 40, and was assembled to have a capacity of 5 liters so that the average residence time of the second loop reactor 12 was about 5 minutes. The inner surface of the stainless steel pipe was electropolished so that the scale was not easily adhered, and the inner surface had a surface roughness of 0.7 μm.

(1) The flow rate of the first loop reactor 11 is set to 5
The reaction was carried out under the same conditions as in Example 1 except that the flow rate of the second loop reactor 12 was set at 2 m / sec and the flow rate of the second loop reactor 12 was set at 2 m / sec.

(2) The degree of butyralization of the first and second loop reactors 11 and 12 was measured in the same manner as in Example 1 15 minutes after the start of the introduction of the polyvinyl alcohol solution and butyraldehyde. 11
Outlet is 41 mol%, the second loop reactor 12
At the outlet was 56 mol%.

(3) After aging for 1 hour at 85 ° C. in the aging tank 2, the butyralization degree of the resin was measured in the same manner as in Example 2, and the result was 66 mol%. 100 g of resin and plasticizer 4
After mixing with 0 g, the mixture was pressed at 150 ° C., and the melt viscosity at 140 ° C. was measured under a load of 20 kg / cm ^{2 using} a Koka type flow tester. The result was 6.8 × 10 ⁴ poise.

(4) After the completion of the reaction, the scale adhesion in the first and second loop reactors 11 and 12 and the aging tank 2 was confirmed. As a result, no scale adhesion was observed. Also, white granules
No coalescence of the particles was observed in the resin in the shape of a circle.

Example 3 Using the apparatus shown in FIG. 4, a polyvinyl butyral resin was synthesized according to the following reaction operations (1) to (4).

This apparatus is the same as that of the first embodiment except that the first loop reactor 11 and the second loop reactor 12 have the following structures.

The first loop reactor 11 was formed of a glass-lined pipe having a diameter of 40, and was assembled to have a capacity of 1 liter so that the average residence time of the first loop reactor 11 was about 1 minute. The surface roughness of the used glass lining pipe was 0.3 μm.

The second loop reactor 12 has a diameter of 25 mm.
A glass-lined auxiliary tank 2 with a capacity of 3.5 liters
0 was provided to make the total volume 5 liters. Tank 2
At 0, a stirring device made of glass lining was set, and the shape of the stirring wing was an irrigated type.

(1) The flow rate of the first loop reactor 11 is set to 5
m / sec and the flow rate of the second loop reactor 12
The flow rate in the pipe section was 2 m / sec, the stirring in the tank 20 was at a rotation speed of 250 rpm, the peripheral speed of the stirring blade was 2 m / sec, and the usage efficiency was 10 w / liter. Otherwise, the reaction was carried out under the same conditions as in Example 2.

(2) After 15 minutes from the start of the introduction of the polyvinyl alcohol solution and butyraldehyde, the butyralization degree of the resin sampled at the outlets of the first and second loop reactors 11 and 12 was measured in the same manner as in Example 2. As a result, in the first loop reactor 11, 41 mol%
In the loop reactor 12, the content was 55 mol%.

(3) After aging for 1 hour at 85 ° C. in the aging tank 2, the degree of butyralization of the resin was measured in the same manner as in Example 2, and the result was 65 mol%. 100 g of resin and plasticizer 4
After mixing with 0 g and pressing at 150 ° C., the melt viscosity at 140 ° C. was measured under a load of 20 kg / cm ² with a Koka flow tester. The result was 7.0 × 10 ⁴ poise.

(4) After completion of the reaction, the scale adhesion in the first and second loop reactors 12 and the aging tank 2 was confirmed.
No scale adhesion was observed. Also, a white granular tree
No coalescence of particles was observed in the fat.

Comparative Example 5 (1) As a preliminary reaction, only the glass-lined loop reactor having a volume of 1 liter used in Example 2 and used in Example 2 was used.
7 was put into the aging tank 2.

(2) The butyralization reaction was carried out under the same conditions as in Example 1 .

(3) The degree of butyralization at the outlet of the first loop reactor 11 was measured in the same manner as in Example 1.
It was 1 mol%.

(4) After aging for 1 hour at 85 ° C. in the aging tank 2, the degree of butyralization of the resin was measured by the same method as in Example 2. The result was 60 mol%. The reaction was continued until the butyral degree was 65 mol%. It took two hours to proceed.

(5) After completion of the reaction, the first loop reactor 1
No scale adhesion was observed in the ripening tank 1 and in the aging tank 2, but a block having a diameter of 1 cm was found in the aging tank 2.

[0092] In Comparative Example 6 (1) Example 2, pre-reaction, the first loop reactor 11 pipe, except that the stainless steel pipe that smoothing the inner surface by electrolytic polishing, the reaction under the same conditions as in Example 2 Was carried out. The used stainless steel pipe has a surface roughness of 0.7
Met.

(2) The degree of butyralization of the first loop reactor 11 and the second loop reactor 12 after one hour of aging was the same as in Example 2 . After the reaction was completed, a scale of about 10 μm was observed on the pipe of the first loop reactor 11.

[0094] In Comparative Example 7 (1) Example 2, in the preliminary reaction, except that the flow rate of the first loop reactor 11 was 4m / sec, Example
The reaction was carried out under the same conditions as in Example 2 .

(2) The degree of butyralization of the first loop reactor 11 and the second loop reactor 12 one hour after aging is as follows:
Each was the same as Example 2 .

After the completion of the reaction, there was no adhesion on the linear portion of the loop reactor, but adhesion of a partially suitable scale of about 5 to 10 μm was found on the bent portion.

[0097] In Comparative Example 8 (1) Example 2, in the preliminary reaction, except that the flow rate of the first loop reactor 11 to 1.5 m / sec, the actual
The reaction was carried out under the same conditions as in Example 2 .

(2) The degree of butyralization of the first loop reactor 11 and the second loop reactor 12 after one hour of aging is as follows:
In the first loop reactor 11, it was 42 mol%, and in the second loop reactor 12, it was 53 mol%. 1 in aging tank 2
The degree of butyralization after standing for a time was 63 mol%. From these results, it was considered that the flow rate (stirring) in the preliminary reaction step contributed to the reaction rate.

[0099]

According to the present invention, it is possible to obtain a resin having an improved solvent solubility and a reduced melt viscosity,
The scale can be prevented from adhering to the inner wall of the device. In particular, as described above, when the reaction is performed by dividing the reaction up to the butyralization degree indicating desirable physical properties into three, the scale does not adhere, the reaction time is short, and
In addition, an efficient process can be obtained in production on a commercial scale.

[Brief description of the drawings]

1 is a schematic explanatory view showing a comparative example of the apparatus used in the method of manufacturing a polyvinyl butyral resin.

FIG. 2 is a schematic explanatory view showing one embodiment of an apparatus used for the method for producing a polyvinyl butyral resin of the present invention.

FIG. 3 is a schematic explanatory view showing another embodiment of the apparatus used in the method for producing a polyvinyl butyral resin of the present invention.

FIG. 4 is a schematic explanatory view showing still another embodiment of the apparatus used in the method for producing a polyvinyl butyral resin of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyvinyl alcohol dissolution tank 2 Ripening tank 3 Butyraldehyde tank 4 Supply pipe 5 Transfer pipe 6 Supply pipe 7 Circulation pump 8 Pressure gauge 9 Flow meter 10 Loop reactor 11 First loop reactor 12 Second loop reactor

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 8/28 C08F 16/34

Claims (1)

(57) [Claims] 1. A polyvinyl alcohol dissolving tank, a butyraldehyde tank, a first loop reactor for reacting a polyvinyl alcohol solution supplied from the polyvinyl alcohol dissolving tank and butyraldehyde supplied from the butyraldehyde tank, and a second loop reactor. Loop reactor
Using a reactor composed of over and aging tank and a manufacturing apparatus having a, a method of producing a polyvinyl butyral resin
There are, butyralization degree of up to at least 40 mol% reaction first performed in a loop reactor and the following (A) ~
(C), the reaction having a butyralization degree of at least 40 to 55 mol% is carried out in the second loop reactor.
And polyvinyl butyral resin of the manufacturing method the flow rate of the reaction time of the solution and carrying out under the conditions described above 2m / sec carried out by: (A) wetted part of the reactor is made of glass, (B) The surface roughness Rz of the liquid contact portion of the reaction apparatus is 0.5 μm or less (provided that the surface roughness Rz is measured using a stylus type roughness meter in accordance with the measurement of ISO R468. (C) The flow rate of the liquid at the time of the reaction, which is the average roughness of 10 measured values, is 5 m / sec or more.