JPS59213711A - Continuous conditioning of syrup - Google Patents

Abstract

PURPOSE:To perform a continuous conditioning of a viscous polymer solution without attaching and/or clogging of the polymer, by continuously mixing, in a liquid phase under a pressurized state, a non-conditioned syrup and conditioned one followed by flush evaporation, deaeration, and cooling to make the conditioned syrup, part of which being returned for said mixing. CONSTITUTION:In order to condition a viscous polymer solution (syrup) so as to be adapted to succeeding treatment processes, a non-conditioned syrup and conditioned one are continuously mixed, in a liquid phase under a pressure 1- 20atm., in a weight ratio of the former to the latter 1:1-200 to make a 1-70 deg.C mixed syrup, which is then subjected, under a pressure 1-200Torr, to continuous flush evaporation, deaeration, cooling, and, if required, concentration, to prepare a 0-50 deg.C conditioned syrup, part of which is returned for said mixing, the rest being provided for succeeding treatment processes, thus accomplishing the objective continuous conditioning.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preparing viscous polymer solutions (hereinafter referred to as syrups) to make them suitable for use in subsequent processing steps, such as decoating.

More specifically, the present invention continuously mixes an unconditioned syrup, such as a methyl methacrylate syrup, and a recycled conditioned syrup in a constant ratio in a mixing zone, and controls the temperature and pressure under specified conditions. The mixed syrup is discharged internally or into a flash evaporation zone under reduced pressure for degassing, cooling and, if necessary, concentration to form a prepared syrup;
Continuous syrup preparation method for obtaining a stable and homogeneous prepared syrup over a long period of time without causing polymer adhesion or blockage or syrup deterioration by reusing a portion as a mixed syrup and sending the remainder to subsequent processing steps Regarding.

Methods for spinning, forming films, or forming plates from viscose compositions, methyl methacrylate syrups, and other viscous polymer solutions (hereinafter collectively referred to as syrups) are known. These syrups require adjustment operations such as deaeration, defoaming, cooling, concentration, or addition of various additives before being subjected to processing steps such as spinning, film forming, or plate forming. If the air or other gases in the syrup are not removed, the filaments will break during spinning, and air bubbles and pores will appear in the filaments during film casting and sheet cast polymerization, which will affect the appearance of the product. A problem arises that significantly impairs physical properties. Therefore, for example, the production of methyl methacrylate syrup usually involves
A polymerization initiator and other necessary additives are added to the methyl methacrylate syrup, which is then degassed under reduced pressure to remove the dissolved air contained therein. Batch-type cell casting method, in which steel is injected between lath plates and polymerized under heating, or continuous cell casting is injected between two continuous moving bands, each end of which is sealed with two gaskets, under heating. This is done by a continuous casting method that involves polymerizing and making plates. The existence of air or other gases is usually divided into two types: one is a mixed gas that is mixed in the form of air bubbles in the syrup, and the other is a dissolved gas that is dissolved in the syrup. . However, in the cast polymerization of syrup, gases such as nitrogen and carbon dioxide generated by the decomposition of the added polymerization initiator are added to the above-mentioned mixed gases and dissolved gases, so foaming during plate making or A higher degree of deaeration is required to prevent undercarriage foaming. That is,
If mixed gases and dissolved gases present in the syrup are not removed, air bubbles may become fixed during heating polymerization, or the solubility of dissolved gases may decrease, resulting in foaming, so degassing is used to prevent this. If this degassing is not carried out to a very high degree, sufficient solubility will not be ensured for the gas generated by the decomposition of the polymerization initiator to dissolve completely in the resin plate, which will also result in foaming. It is.

Methods for removing mixed gases and/or dissolved gases include:
There are two known methods: the batch method, in which the syrup is left in a container and vacuum degassed, and the wet wall method, in which the syrup is continuously vacuum degassed while flowing down on the wall as a thin film. Since it takes a long time to process and is not suitable for processing a large amount of syrup, the latter method is preferred, and various improved methods have been proposed.

In Japanese Patent Publication No. 35-8557, viscous liquid (syrup)
When degassing a thin layer of liquid by placing it under reduced pressure, the pressure and temperature of the liquid against the vacuum layer are adjusted so that the temperature difference between the liquid before and after the solvent is separated remains almost constant, and the liquid is boiled. Mixable or dissolved by a viscous liquid, or mixed or dissolved by a viscous liquid, which prevents agglomeration or skin formation by flowing the film so that the surface of the device that is to be in contact with liquid droplets is always coated with a flowing film of liquid. A method for removing contaminated air or gas is disclosed. This method applies a vacuum high enough to boil the falling film to ensure complete deaeration, and then washes all wet parts of the vacuum chamber with a continuous flow of film, causing the boiling solution to scatter onto the dry part of the primordium. However, if the viscosity of the viscous liquid to be treated is high, degassing tends to be insufficient, and the amount of liquid coming out between the tongues to form a fluid film is considerable. It is inevitable that the droplets or foam will reach the dry part of one tongue, and if it forms a skin and is used continuously for a long time, the skin may fall off or block the gap between the tongues. This has the drawback of inhibiting the formation of a continuous film.

Furthermore, in JP-A-58-118882, polymerizable syrup is injected from a syringe, passes through the gap between the syringe and the cap-shaped wet wall, and forms a film flow onto the cap-shaped wet wall. A method for producing a defoamed sill sludge is disclosed in which air bubbles or dissolved gas in the sill sludge or air bubbles and dissolved gas are removed by flowing down the sill sludge and vacuum degassing is performed.

In this method, bubbles are broken when they are injected into the L end of the wetted wall through a circumferential gap between the injector and the wetted wall, and then the syrup flows down as a film flow along the wetted wall. This is intended to improve the defoaming efficiency by removing air bubbles and dissolved gas remaining between the wet walls, but even though the bubble-breaking effect can be adjusted by adjusting the circumferential gap, the desired It is not always easy to form a film flow with a film thickness of .

On the other hand, as the manufacturing method for methacrylic resin sheets is changing from the conventional batch-type cell casting method to the highly productive continuous casting method, there is a need for a syrup manufacturing method that enables higher productivity. For example, JP-A-54-54188, JP-A-54-54189
Continuous methods have been proposed, such as , and Japanese Patent Application Laid-Open No. 55-147514. These methods use syrups that have a higher polymer content and higher viscosity than those used in conventional cell casting methods. Also, continuous cast method and/or
Alternatively, since the purpose of the continuous syrup manufacturing method is to mass-produce a small number of varieties with constant quality, the syrup adjustment process that is interposed between the syrup manufacturing process and the plate making process is naturally a method that meets that purpose. is requested.

For example, the method disclosed in JP-A-44-99184, in which a polymerization initiator and optionally various additives are continuously mixed into syrup, meets this purpose.

As a result of intensive study by the present inventors on a method that overcomes the drawbacks of existing deaeration methods and also contributes to the above-mentioned continuous request,
The degassed syrup is circulated and mixed at a fixed ratio with the undegassed syrup, adjusted to the specified conditions, and then flash evaporated under the specified conditions, and the evaporated volatile components are condensed and refluxed to produce a heavy It was discovered that a homogeneous defoamed syrup can be obtained stably for a long period of time without causing coalescence clogging or syrup deterioration, and furthermore, the undegassed syrup can be discharged from the continuous syrup production process in which monomers are continuously polymerized in bulk. The present inventors have discovered that there is a simple continuous adjustment method in which deaeration and cooling can be carried out simultaneously and efficiently in the case of a hot syrup produced by a heat treatment.

That is, the present invention maintains a liquid phase state under a pressure of 1 to 20 atm at a weight ratio of 1:1 to 200 by weight of unconditioned syrup and adjusted syrup in adjusting the syrup to be suitable for subsequent processing steps. and continuously mix at a temperature of 1 to 70℃.
The mixed syrup is heated to a pressure of 1~2°C.
Continuous flash evaporation under Q Q Torr conditions, deaeration, cooling, and concentration if necessary, to a temperature of θ to 50°C.
1. A method for continuously preparing syrup, which comprises using a portion of the prepared syrup in the mixed syrup described in L, and using the remaining portion in a subsequent processing step.

Next, the present invention will be explained in detail.

There are no particular restrictions on the type of syrup suitable for condensation according to the method of the present invention, and a viscous polymer solution prepared by dissolving a polymer in a solvent and/or a monomer is generally used.
Preferably, methyl methacrylate syrup is produced by partially polymerizing a raw material liquid consisting of 100 to 80% by weight of a monomer mainly composed of methyl methacrylate and θ to 20% by weight of a rubbery polymer, and particularly preferred. 90-20 obtained by continuous bulk polymerization in the presence of a radical polymerization initiator
Examples include methyl methacrylate syrup under a temperature condition of 0°C. At this time, as the monomer whose main component is methyl methacrylate, methyl methacrylate is used alone, or alkyl acrylates such as methyl acrylate and ethyl acrylate that can be copolymerized with methyl methacrylate, ethyl methacrylate, lauryl methacrylate, and ethylene glycol. Alkyl methacrylates such as dimethacrylate, unsaturated nitriles such as acrylonitrile, unsaturated amides such as acrylamide, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, vinyls such as styrene, α-methylstyrene, and P-methylstyrene. Methyl methacrylate contained in an amount of 40% by weight or less, preferably 20% by weight or less based on the remainder of the ethylenically unsaturated monomer exemplified by aromatic compounds, maleic anhydride, N-arylmaleimide, etc. A mixture of monomers is used. Rubber-like polymers include homopolymers such as polybutadiene, polyisoprene, polyisobutylene, butadiene/styrene, butadiene/
Diene copolymers such as acrylonitrile, ethylene/
Vinyl acetate copolymer, ethylene/alkyl acrylate copolymer, rubbery polyalkyl acrylate, polyurethane,
Rethane, chlorinated polyethylene, EPDM, etc. are 0 to 20% by weight, preferably 2 to 10% by weight based on the total amount of the raw material liquid.
It is added within a range of % by weight. There is no particular restriction on the radical polymerization initiator, and for example, an azo compound such as azobisin butyronitrile, or a peroxide such as benzoyl peroxide or lauroyl peroxide is usually used in an amount of o, oot to 1 per 100 parts by weight of the raw material solution. Parts by weight, preferably 0
．． 01 to 0.5 polydispersed parts are used.

In particular, the polymer content, viscosity, and number average degree of polymerization in the syrup do not have a direct correlation with the degassing and/or cooling effect in the preparation method of the present invention, polymer adhesion clogging, syrup deterioration, etc. Although there is no limitation, from the viewpoint of using the obtained syrup in subsequent processing steps, the polymer content in the syrup is 5 to 40% by weight, preferably 10 to 80% by weight, and the viscosity at 25°C is 0. 5
~500 Po The conditioning in the process of the invention consists of a mixing zone and a flash evaporation zone. The unconditioned syrup is first continuously fed into the mixing zone, while the conditioned syrup is also continuously mixed at a constant rate. There is no particular limit to the temperature of the unadjusted syrup, and cold syrup that is stored in a storage tank and mixed with various additives as necessary can be used.
9 which is preferably continuously discharged from the continuous bulk polymerization step.
High temperature syrup under temperature conditions of 0 to 200°C is used as is. The temperature of the adjusted syrup used here is about 0 to 50°C, preferably about 10 to 40°C, and this temperature is determined from the viewpoint of using the syrup in the subsequent processing step and the operating conditions of the flash evaporation zone described below. However, if it is higher than this range, the polymer will adhere to the mixing area, circulation line, etc., gradually grow, and change into an insoluble polymer, resulting in blockage. The circulating amount of adjusted syrup is 1 for the amount of unadjusted syrup.
~200 times the weight, preferably 2 to 50 times the weight.

If the amount of the prepared syrup is too small, sufficient degassing will be difficult during flash evaporation, and furthermore, a sufficient mixing cooling effect will not be obtained for the high temperature syrup, resulting in the aforementioned polymerization blockage. On the other hand, if the amount exceeds this range, the amount of adjusted syrup that has been adjusted will simply need to be adjusted again, which is wasteful and undesirable. There are no particular restrictions on the structure of the mixing zone as long as it has the function of substantially uniformizing the mixed or dissolved gas concentration and/or temperature, and mixing by stirring is not essential; Additives for subsequent processing steps or the final product, such as additives, UV absorbers, etc., may be added to mix them more quickly and uniformly, or to prevent polymer build-up within the mixing zone. Preferably, there is a stirring operation. Although there are no particular restrictions on the mixing state in the stirring operation, complete mixing is desirable and a complete mixing stirring tank is suitable for this purpose. There is no particular restriction on the shape of the stirring blade, examples include double helical ribbon g, MIG.
Type stirring blades etc. can be used. The stirring vanes are preferably arranged to wipe the unconditioned syrup inlet opening, and the unconditioned syrup entering the mixing zone is immediately mixed and dissolved into the conditioned syrup. The rotational speed of the stirring blade is not particularly limited, but is usually selected from 50 to 1,000 rpm. The average residence time in the mixing zone may be as short as generally one minute or less, as long as it is sufficient to substantially uniform the concentration and/or temperature of the mixed or dissolved gases.

The temperature of the mixed syrup obtained in the mixing zone is adjusted to 1-20°C, preferably 2-15°C higher than the temperature of the prepared syrup. Therefore, the temperature of the mixed syrup is usually 1~
70°C, preferably within the range of 12-55°C. If the temperature difference is smaller than the above-mentioned axis, the amount of volatilization in the flash evaporation zone will be too small, and conversely, if the temperature difference is greater than this range, the amount of volatilization will be excessive, which is not preferable for the reasons described later. In order to achieve the temperature difference conditions, the temperature of the conditioned syrup and the mixing ratio to the mixed syrup are adjusted, but if necessary, external heating may be applied in the mixing zone, and the unconditioned syrup is preheated. may be fed to the mixing zone. From this point of view, the methyl methacrylate syrup obtained by continuous bulk polymerization in the presence of a radical polymerization initiator at a temperature of 90 to 200°C is continuously supplied to the mixing zone as unadjusted syrup. This is extremely suitable. The vapor pressure of the mixed syrup is less than atmospheric pressure, but sufficient to maintain the syrup in a liquid phase immediately before entering the flash evaporation zone so that the syrup is efficiently flash evaporated in the zone. It is necessary to apply this pressure, which is usually 1 to 20 atmospheres,
Preferably it is 4 to 10 atmospheres.

Flash evaporation involves discharging the mixed syrup under a pressure of 1 to 20 atm at a temperature of 1 to 70 °C as described above in a flash evaporation zone maintained under pressure conditions of 1 to 200 Torr, preferably 5 to 1 Q Q Torr. It is done by doing.

Here, a portion of the volatile components from the mixed syrup instantaneously evaporates, thereby removing gases mixed and dissolved in the mixed syrup, cooling the syrup, and concentrating the syrup.

If the ratio of volatile components that flash evaporates to the amount of mixed syrup is defined as the volatility rate, this volatility rate is usually 0.5 to 20.
% by weight, preferably 1 to 10% by weight is suitable.

If the volatility rate is too low, removal of dissolved gases mixed into the syrup, cooling of the syrup, and concentration of the syrup will not be performed sufficiently.
Also, if the volatility is too high, the syrup will be concentrated more than necessary, the viscosity of the syrup will increase dramatically, and the normal flow state will be inhibited, which is undesirable. It will be done. The higher the temperature of the mixed syrup and the lower the pressure in the flash evaporation zone, the higher the volatilization rate.

The degree of cooling of the syrup depends on the rate of volatility.

The volatile components are cooled and condensed, and part or most of this condensate is refluxed to syrup.

The degree of concentration of the syrup can also be adjusted by adjusting the amount of reflux. That is, when concentrating a syrup with a dilute concentration, it is sufficient to increase the volatility rate and reduce the reflux amount.

Note that excessively concentrated syrup does not mix easily even if the condensed volatile components are refluxed back, so it is desirable that the volatility rate does not exceed the first limit shown above.

The primary equipment components of a flash evaporation zone suitable for the present invention specifically include a tower vessel, a reflux condenser, and a syrup injection nozzle. The reflux condenser is installed in the upper part of the tower-shaped container, and the injection nozzle 5 is opened at the upper part of the tower-shaped container. The volatile components evaporated in the tower-like container are cooled and condensed in the reflux condenser and refluxed to the top of the tower, and a reflux path is installed so that the injection nozzle and/or the wall of the tower are perfused.

As a result, droplets and foam emitted from the tip of the injection nozzle and reaching the back of the nozzle and tower wall surface moistened with volatile component liquid are easily washed away by the constantly flowing reflux liquid, or are redissolved and removed, allowing them to dry out. This prevents the skin from forming and causing a blockage, or from falling off and becoming a foreign object in the product. The mixed syrup discharged from the tip of the injection nozzle expands explosively, and bubbles are usually burst or dissolved gases are removed instantaneously, so it does not necessarily have to form a thin layer and flow down, but it flows directly to the bottom of the tower. In order to prevent this, and to ensure complete re-melting, spray directly onto the inner wall of the tower or remove the inserted material. It is preferable to provide a surface and allow the liquid to collide with the surface and flow down. Suitable such inserts are, for example, flat plates or plates with a downward slope from the center towards the periphery, which are placed below the injection nozzle inside the tower-like container and the discharged syrup is directed to the plate. At the top, it is preferably allowed to flow in a thin layer, coating the column wall and flowing down, during which time the dissolution of the reflux liquid is completed and it joins the liquid distillate at the bottom of the column as a prepared syrup. There is no particular limit to the amount of retention at the bottom of this tower-like container, and it may serve as a buffer tank to adjust the balance with the amount used in subsequent treatment steps.

In the process of the invention, the crude syrup has a viscosity of 0.5 to 500, which is the viscosity range in which syrups of this type are normally used.
Even in the case of the internal viscosity side of the void, the removal of mixed dissolved gas is complete, and even if film breakage occurs on the wall surface of the evaporation tower, there is no deterioration in deaeration efficiency or the formation of skins. Furthermore, it has been found that even when the unadjusted syrup is at a high temperature, it can be cooled without causing polymer adhesion and clogging or deterioration of the syrup, and the above-mentioned degassing is even more convenient.

That is, according to the method of the present invention, when preparing syrup to be suitable for subsequent processing steps, degassing and/or degassing can be carried out stably for a long period of time without causing deterioration of the syrup due to polymer adhesion clogging or skin formation. Alternatively, a simple and efficient continuous preparation method is provided in which a homogeneous prepared syrup can be obtained by cooling.

The syrup prepared by the method of the present invention is usually made into a polymerizable liquid composition by adding and dissolving a polymerization initiator, and is suitable for manufacturing one resin board by cell casting method or continuous casting method, or manufacturing glass fiber reinforced resin board. However, it is preferably used for continuous casting or continuous production of glass fiber reinforced resin plates, and is a method in which additives such as polymerization initiators are continuously mixed, especially when mass producing a small number of products with constant quality. It is effective when used in combination with The most preferred example of application is the syrup preparation process interposed between the continuous syrup manufacturing process and the continuous cast board manufacturing process, but it may also be used for applications that do not require degassing, such as adding a polymerization initiator to rubber-modified syrup. A suspension for producing an impact-resistant molding material by adding and dissolving the composition to form a polymerizable liquid composition, dispersing the composition in an aqueous medium under stirring in the presence of a suspension stabilizer, and polymerizing and solidifying it by heating. It can also be used in the turbidity polymerization method.

EXAMPLES Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited by these examples. In addition,
In the examples, % is weight %, and parts are weights. In addition, measurements were made using 1008 in the examples.

Example 1 A two-stage continuous reaction device consisting of a stirred tank type reactor with a double helical ribbon i< installed in the first stage and a tubular reactor arranged in the second stage, a stirred tank type with a double helical ribbon wrapper installed on the outlet side. The mixing cooler is directly connected to the upper part of the flash evaporation tower, which is equipped with a reflux cooler at the upper part, and the injection nozzle has an opening in the tower and a pipe with a back pressure valve installed on the downstream side of the injection nozzle. A continuous system was used in which the bottom of the evaporation tower and the mixing cooler were connected by a circulation path via a gear pump.

The volume of the seed reactor is 0.56, and the stirring speed is so
rprn, the tubular reactor has an inner diameter of 13 mm and a length of 80 mm.
A full-jacket, double-tube type device was used to circulate the heat medium to the outside, and an opening was opened in the body of the mixing cooler. The volume of the mixing cooler was 0.2e, and the stirring speed was 500 rpm. In addition, the heat transfer area of the reflux condenser is 0.2 doors,
The diameter of the flash evaporation column is 21011 mm at the top. The bottom is 1
At 60H, a flat plate with a diameter of 18 Off was installed near the boundary of the image area, and an injection nozzle with an outlet diameter of 25 Off was opened approximately 100 Off above the center of the flat plate. 100 parts of methyl methacrylate monomer and 0.047 parts of azobisisobutyronitrile were continuously supplied to a seed reactor, and the reaction temperature was 160°C.
Polymerization was carried out at a pressure of 6 atm and an average residence time of 147 seconds, followed by passage through a tubular reactor whose jacket was heated with heat transfer oil at 220°C to a temperature of 175°C to substantially annihilate residual initiator. Syrup is continuously fed into the mixing cooler at a rate of 11.6 Kg/hour, while 16 kg/hr of conditioned syrup at 30°C, which has previously been heat removed in a flash evaporation tower vessel, is
They were supplied at a rate of 0 Kq/hour, and both were stirred and mixed in the mixing cooler and rapidly cooled to 40°C. The mixing ratio of conditioned syrup to hot syrup was approximately 14 times by weight, and the pressure in the mixing cooler was maintained at 6 atmospheres by a back pressure valve. Next, the mixed syrup is continuously discharged through an injection nozzle into a flash evaporation column whose interior is under a pressure condition of 59 Torr, where it is simultaneously degassed and cooled.The evaporated volatile components are condensed and refluxed in a reflux condenser. The injection nozzle, insertion plate and inner column wall were perfused. The volatilization rate of volatile acids during flash evaporation is a low value of about 4% relative to the amount of mixed syrup, and the reflux liquid is easily redissolved into syrup while flowing down in the tower-like container, making it possible to obtain a uniform adjusted syrup. Ta. The adjustment
The whelks were extracted from the bottom of the tower using a gear pump, a portion of which was used in the subsequent process, and the remainder of which was supplied to the mixing cooler. Polymerization conversion rate of adjusted syrup is 25.4%, 25℃
The viscosity of the syrup was 13.5 poise, the number average degree of polymerization of the polymer in the syrup was 740, the dissolved oxygen concentration was 0 ppm, and no foreign matter such as coloring or skin was observed.

Continuous operation was carried out for 700 hours under the above syrup production and adjustment conditions, during which time the polymerization conversion rate, viscosity, etc. could be maintained substantially constant. Further, after stopping the continuous operation, the reactor, mixing cooler, and flash evaporation tower were opened and inspected, and no polymer was observed inside any of them.

In this prepared syrup, 0.1% of a paste made by dispersing azobisdimethylvaleronitrile in an equal amount of dibutyl phthalate as a polymerization initiator was continuously dissolved to obtain a polymerizable liquid composition, and the belt gap was adjusted to 8H. It was injected into a known continuous polymerization apparatus set at 85°C for 24 minutes, then 1
Polymerization was completed by heating at 20° C. for 8 minutes to produce a resin plate.

This product was colorless and transparent with no bubbles observed and had a good appearance.

Comparative Example 1 The same equipment and operating conditions as Example 1 were operated, except that the feed of the prepared syrup was stopped, so that the hot syrup was subjected to direct flash evaporation. The volatility rate of volatile components is 5
0% or more, and the viscosity of the syrup after volatile component separation is also t.
, ooo voids or more, the flash evaporation was not completed instantaneously and foaming continued, and the syrup remained at the top of the column, making it difficult to flow down due to its own weight, making it impossible to continue operation.

Example 2 The apparatus of Example 1 was used. Raw material solution 9 consisting of 5% polybutadiene rubber (Asahi Kasei Co., Ltd. diene NF-a5A), 79% methyl methacrylate, and 16% styrene.
0 part of benzoyl peroxide and an initiator solution prepared by dissolving 0.1 part of benzoyl peroxide in 10 parts of methyl methacrylate were used as feed liquids for the seed reactor, and the average residence time in the reactor was 160 seconds. Polymerization was carried out under the same conditions as in Example 1, and then the circulating feed rate was increased to 1 O, 7 kg/h from the tubular reactor to the mixing cooler.
Flash evaporation was carried out under the same conditions as in Example 1 except that the temperature was 50 Kp/hour to obtain a prepared syrup at 30°C.

The polymerization conversion rate of monomers in the ship was 26.5%,
The viscosity at 25° C. was 24.1 poise, and the average particle size of the dispersed rubber particles was 0.5 μm. Continuous operation was carried out for 850 hours under the above conditions, during which time the polymerization conversion rate, viscosity and rubber particle size remained substantially constant.

Furthermore, when the apparatus was opened and inspected after continuous operation was stopped, no polymer was found to be attached to any part. A polymerizable liquid composition was prepared by dissolving 8 parts of methyl acrylate, 0.8 parts of lauroyl peroxide, and 0.8 parts of lauryl mercaptan in 100 parts of this prepared syrup, and partially saponified polyvinyl as a suspension stabilizer in 150 parts of water. Alco ■ Ichiru (Nippon Gohsei Cosenol GM-14,)
The mixture was charged into a seed reactor equipped with a stirrer together with an aqueous medium in which 0.1 part was dissolved, and after stirring and dispersion, the mixture was heated under a nitrogen atmosphere to an internal temperature of 90°C and polymerized with stirring for 2 hours.
The polymerization was completed by heat treatment at an internal temperature of 110° C. for 30 minutes to obtain a bead-like polymer. The ASTM 1,1-6 molded product obtained by injection molding this polymer at 270°C and having a thickness of 3 to 3
The total light transmittance measured in accordance with A.72 was 92%, the diffusivity was 1.8%, the heat distortion temperature was 102°C measured in accordance with A, STM D-548, and ASMD-256.
The Izot impact value (with notch) measured in accordance with
．． 5 and C1n/crn and was of extremely high quality.

Comparative Example 2 A continuous device in which a corrugated pipe cooler was arranged on the outlet side of the two-stage continuous reaction device of Example 1 was used. The inner diameter of the snake pipe is 1
It was 3 m long and 8 m long, equipped with a water cooling jacket, and the outlet side was connected to the receiver via a back pressure valve.

Polymerization was carried out under the same reaction conditions as in Example 2, and then the mixture was passed through a corrugated tube cooler whose jacket was cooled with cold water at 20°C and whose interior was maintained at 6 atm, and taken out of the system as a cold syrup at 50°C. child. The polymerization conversion rate of monomers in the syrup is 27.3%, and the viscosity at 25°C is 34.8.
The average particle diameter of the poise and dispersed rubber particles was 0.8 μm, and enlargement due to polymerization reaction and progress during the cooling process and condensation of the rubber particles was observed. From around 3:11:41pm after the start of continuous operation, the temperature at the syrup outlet began to rise and an increase in pressure loss in the system was observed, so the operation was stopped after 20 hours and the reactor and cooler were opened and inspected. , condenser inlet restriction 8) Blockage of polymer across layers was observed. The occlusions were of high molecular weight and largely insoluble in chloroform.

Example 3 Instead of the two-stage continuous reaction apparatus of Example 1, an apparatus was used in which the supply piping from the syrup consolidation tank was connected to a mixer. 77.5 parts of methyl methacrylate monomer and 20 parts of methacrylic resin (SumiPex O-BMW, manufactured by Sumitomo Chemical Industries)
A syrup obtained by dissolving 1 part and 2.5 parts of trimethylolpropane triacrylate at a temperature of 30°C and a viscosity of 1.9 poise at 25°C was continuously added to a mixer at a rate of 9 to 7 parts. Meanwhile, pre-flash evaporated prepared syrup was fed at a rate of 40 Kf/hr, and 0.26 part of inpropyl cumyl peroxy neodecanoate, which is a polymerization initiator for the subsequent step, was added to methyl methacrylate monomer. An initiator solution dissolved in 10 parts of polymer was continuously fed at a rate of I kg/hour, and these were stirred and mixed in the mixer, and the temperature was adjusted to 15° C. and 5 atm.

The circulation ratio of syrup in the mixer was 4 times by weight. The mixed syrup was then passed through a flash evaporation column under the same conditions as in Example 1 except that the interior was under a pressure condition of 20 TOOr to obtain a prepared syrup. The temperature of this syrup is 12°C, and the dissolved oxygen concentration is o ppm
Met. This syrup is injected into a flat polymerization mold uniformly filled with glass fibers (CR-218-LA-75 manufactured by Nippon Glass Fiber Co., Ltd.) so that the final resin plate contains 25% to impregnate the glass fibers. Then, this polymerized mold was immersed in a heating bath at 85°C, and no polymeric foaming was observed in the resin plate with a thickness of 0.7 m despite the short polymerization time.

Example The same apparatus as in Example 1 was used, except that a portion of the reflux liquid was discharged outside the system, and the apparatus was operated under the same conditions. The amount of reflux liquid discharged outside the system is 2. OKt / time,
This corresponded to about 30% of the amount of volatile components vaporized and condensed in the flash evaporation tower. The polymer content of the adjusted syrup that is concentrated and cooled and discharged from the bottom of the tower is 30.7%, 25
The viscosity at °C was 68.6 poise. Furthermore, no skin formation was observed on the tower wall.

Claims (4)

[Claims] (1) When preparing a viscous polymer solution (hereinafter referred to as syrup) to be suitable for subsequent processing steps, unadjusted syrup and adjusted syrup are mixed at a weight ratio of i:l to 200 at a pressure of 1 to 20 atm. The mixture is continuously mixed while maintaining the liquid phase state to form a mixed syrup at a temperature of 1 to 70°C, and the mixed syrup is continuously flash evaporated under a pressure of 1 to 2 Q Torr to desorb. A method for continuously preparing syrup, which comprises airing, cooling, concentrating if necessary, and subjecting the syrup to a controlled temperature of θ to 50° C., followed by subsequent treatment steps. (2) 100 to 80% by weight of a monomer mainly composed of syrup or methyl methacrylate and a rubbery polymer θ to 20% by weight
Raw material liquid consisting of % by weight (however, both are 100% by weight in total)
The method according to claim (1), wherein the syrup is a methyl methacrylate syrup obtained by partially polymerizing . (3) The method according to claim (1), wherein the syrup has a polymer content of 5 to 40% by weight and a viscosity of 0.5 to 500 poise at 25°C. (4) The unadjusted syrup contains 100 to 80% by weight of a monomer mainly composed of methyl methacrylate and 0 to 2% by weight of a rubbery polymer.
The claim is a methyl methacrylate-1 syrup obtained by continuously polymerizing a raw material liquid containing 0% by weight in the presence of a radical polymerization initiator at a temperature of 90 to 2.00°C. The method according to paragraph (1) 1.