JPS5827802B2 - Method for continuously recovering polymer from polymer latex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously recovering polymer from a polymer latex.

More specifically, the present invention relates to (a) a vinyl polymer latex, (b) a graft polymer latex obtained by emulsion graft polymerization of a vinyl monomer to a rubbery polymer, and (c) (
A polymer latex selected from a mixed polymer latex of (a) and (b) and/or a rubbery polymer latex, and the polymer has the property of being hard at room temperature and softening or melting at 100 to 130°C. The present invention relates to a method for continuously recovering a polymer from a polymer latex containing the same.

Conventional methods for recovering the polymer from polymer latex include mixing the polymer latex with an organic solvent and extracting the polymer with the organic solvent, and adding a so-called coagulant to deactivate the emulsifier contained in the polymer latex. However, the former method has the disadvantage of requiring a great deal of labor to separate the organic solvent and the polymer, and the latter method is usually employed in large quantities. The method is extremely diverse, in which the fine polymers that have coagulated and become liberated are coalesced and granulated, then the powder is dried by filtration or centrifugally dehydrated, and then the powder with a fairly high moisture content is dried in a flash dryer to recover the polymers. process, and has many disadvantages such as high drying cost, large polymer loss during the process, difficulty in avoiding contamination with impurities, and high labor costs.

In order to improve these shortcomings, various studies have been carried out in the past. No. 34-10488), (b)
A paste made of polymer latex and coagulant is shaped,
This modeling paste is heated in an aqueous solution to cure and cure the polymer particles.
No. 5), (Nomaro)'s method of manufacturing Pace l using a screw pump (Special Publication No. 42-22684); A method in which most of the water is dehydrated from the latex, and then the remaining water is evaporated to dryness at the exhaust port located at the tip of the screw, and the molten polymer is continuously recovered (%
Publication No. 50-17277) has been proposed.

However, method (a) uses a compressor, and although most of the water is removed, an extra step of crushing the coagulum is added, and there is still a step of washing and drying the crushed polymer. .

In addition, although the dehydration process is simplified to some extent in the Naka) method and the ←钖 method, there is still room for improvement in the washing and drying process of the granulated material.

In addition, method (d) uses a screw type dehydrator/dryer.
Although it is excellent in terms of simplifying the process of recovering polymer from latex, the mechanical squeezing of the coagulated material is not stable and entrainment of the polymer into the exhaust port (vent amplifier) occurs.
The drawback is that the operation of the screw dewatering and drying machines is unstable, making it difficult to increase productivity.

Therefore, the purpose of the present invention is to improve the drawbacks of the conventional polymer recovery method from polymer latex, and in particular to simplify the dehydration process by improving the effect of mechanical squeezing in the screw type. , to establish a drying method.

Another object of the present invention is to produce a polymer latex that is hard at room temperature and softens or melts at a temperature of 100 to 300°C, with a desirable moisture content and low impurities by simple means. The objective is to continuously recover the dehydrated and plasticized polymer.

According to detailed studies by the present inventors, in a method for continuously recovering polymer from polymer latex, it is possible to continuously perform dehydration, plasticization, and drying by increasing the effect of mechanical squeezing. It has been found that stable operating conditions can be obtained, productivity (yield and cost) is good, and the polymer can be continuously taken out in a molten state and recovered as pellets using a device that can be used.

Polymer latex, which has a low secondary transition temperature, is soft at room temperature, and has some degree of tackiness, such as rubber-like polymers, is made from a slurry polymer consisting of coagulated latex polymer and water ( b) A device that scoops up the polymer with a screw-like object, compresses it in a cylinder whose diameter becomes smaller as it approaches the tip of the cylinder, performs mechanical dehydration, and then kneads it with a screw. A method of recovering the polymer using a device consisting of a die to remove the remaining water. There are commercially available devices that allow residual water to evaporate from the screen bar and recover the polymer from the die, but these devices are hard at room temperature and do not react at temperatures of 100 to 300°C. It is difficult to apply a latex of a polymer that is plasticized in a process and continuously recover the polymer from this latex.

On the other hand, Japanese Patent Publication No. 50-17277 proposes an apparatus for continuously extracting a polymer in a molten state from a latex of such a polymer, but this apparatus also has unstable dehydration in the mechanical squeezing part. There was a problem that the polymer was entrained in the exhaust port located at the tip of the screw, resulting in poor yield.
It became clear that this was insufficient as a stable polymer recovery device.

As a result of intensive research and efforts, the present inventors have found that it is possible to continuously extract a polymer in a molten state with good yield from a polymer latex that is hard at room temperature and plasticized at a temperature of 100 to 300 degrees Celsius. I found a way.

That is, the present invention is hard at room temperature and has a 100%
When recovering a polymer from a polymer latex that becomes soft or molten at a temperature of ~300°C, after coagulating the latex, it is simultaneously squeezed with vinyl polymer pellets or/and beads using a screw type squeezer. The present invention provides a method for recovering a polymer from a polymer latex, which comprises feeding the latex to a dehydrator, dehydrating and drying it, and continuously taking out the polymer in a molten state from a die section at the tip of a cylinder.

Applicable to the present invention, it is hard at room temperature and has a hardness of 100 to 3
Polymer latexes that become soft or molten at 00°C include (a) aromatic vinyl monomers such as styrene and α-methylstyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, methyl methacrylate, Homopolymers of vinyl monomers such as alkyl methacrylates such as ethyl methacrylate, or copolymers thereof, such as styrene-acrylonitrile copolymers, styrene-α-methylstyrene-acrylonitrile copolymers, styrene-methacrylic Vinyl polymers represented by methyl acid-acrylonitrile copolymer, etc. (b) Polybutadiene, butadiene-styrene copolymer (Sf3R), butadiene-acrylonitrile copolymer (NBR), imprene rubber, chloroprene rubber, etc. Diene-based rubbery polymer and acrylic acid ester-2
- emulsion graft polymerization of the vinyl monomer shown in (a) to a rubbery polymer represented by chloroethyl vinyl ether copolymer, ethylene-propylene copolymer, or ethylene-propylene-diene terpolymer; Graft polymer latex and ←J a) and (b) and/
Alternatively, a mixed polymer latex formed by mixing with the rubbery polymer latex shown in (B) can be mentioned, but in the above (B) and ←→, It is preferred that the proportion of the polymer is 85% by weight or less.

In addition, vinyl polymer pellets or/
And vinyl polymer beads are pellets obtained by bulk polymerization of the vinyl monomers shown in (a) above or powder obtained by emulsion polymerization and melted into granular form by extruding them into pellets or/and upper rings. It refers to a bead-shaped polymer obtained by suspension polymerization of the vinyl monomer shown in a).

The amount of vinyl polymer pellets and/or beads supplied is 1 of the total amount of solids in the latex.
It is preferably 0% or more and 60% or less.

If the amount of vinyl polymer pellets and/or beads supplied is less than 10%, the mechanical squeezing will not be sufficient and the subsequent evaporation and drying will be unstable, making it difficult to use as a system for recovering the polymer from latex. In this case, the yield will not increase.

If it is more than 60%, the mechanical squeezing will be too effective, raising the resin temperature, causing discoloration, burning, and mixing of polymer (foreign matter), which is not only undesirable, but also requires the pellet to be passed through the screw again, which is energy-consuming. It is a loss.

A typical process diagram for continuously recovering a polymer from a polymer latex according to the method of the present invention is shown in FIG. 1-1.

One embodiment of the present invention will be described as follows with reference to FIG.

The polymer latex storage tank 1 and the coagulant storage tank 2 are quantitatively fed to the coagulation tank 3 using pumps P-1 and P-2, respectively, where they are stirred and solidified to form a solidified slurry-like mixture. is continuously supplied to the filter 4 as an overflow.

The water filtered by the filter 4 is drained via a water receiver 7.

The filtered polymer cake is quantitatively scraped out and continuously supplied to the dehydrator 8.

On the other hand, a predetermined amount of vinyl polymer pellets is continuously supplied from the vinyl polymer pellet dumper 5 to the filter 4 by the pellet quantitative discharge device 6, and simultaneously supplied to the dehydrator 8 with the polymer cake.

The dehydrator 8 is a screw type dehydrator, and the rear end of the screw has a compression ratio, and has a structure in which mechanical compression is performed.

The rear end cylinder also has a drainage hole, which has an opening that does not allow the polymer cake or pellets to pass through, but allows squeezed water to pass through.

Water mechanically squeezed out of the cake phase is drained through this rear end drain.

There is an exhaust port in the middle of the screw, and a vacuum pump P
-5 and maintained at reduced pressure.

The remaining water in the polymer, which has been mechanically squeezed and dehydrated at the rear end of the screw, is superheated by the kneading energy of the screw, and is evaporated and discharged from the system through the exhaust port in a vacuum state.

The dehydrated and dried polymer is quantitatively extruded by the screw at the tip, uniformly discharged from the die nozzle located at the tip, cut, and collected in the form of cylindrical pellets.

The screw type squeezing dehydrator 8 is a squeezing dehydrating/drying machine that uses a general screw.

Figure 2 shows a typical device.

Figure 2-1 has a drain port 2 at the rear end of the screw, and uses the compression ratio of the screw to provide mechanical throttling.The polymer is sent to the tip, and the squeezed water is sent to the drain port 2 at the rear end. It is discharged outside the twine.

The dehydrated polymer is dried through a vent 3 located at the center of the screw, and is continuously sent to the tip of the screw, where the polymer is recovered in a molten state.

FIG. 2-2 shows a screw type dehydration dryer having a two-stage movable orifice mechanism in the center of the screw.

That is, by moving the movable cones 3 and 5 shown with diagonal lines back and forth, the clearance with the screw is adjusted, and an appropriate degree of constriction (compression) is applied to the resin.

The cylinder consists of screen bars with appropriate gaps that allow water and steam to pass through, but not polymers, cakes, or pellets.

The supplied polymer is compressed as it passes through the first stage orifice, and water is discharged to the rear of the screw and exits the system through the screen.

The mechanically squeezed and dehydrated polymer is heated appropriately as it passes through the second-stage orifice, and the remaining water is discharged from the system as water vapor through the gaps in the screen bar after passing through the orifice. .

The dehydrated and dried polymer is thus appropriately plasticized and continuously extruded to the tip of the screw.

Figures 2-3 show an apparatus that combines an inclined squeeze dewatering screw (conical squeezer) and a vent screw.

The first stage conical squeezer has a screw with a high compression ratio, and the screw is tilted so that the squeezed water can be easily discharged.

The cylinder at the bottom (rear end of the screw) has a screen 2 that allows water to be discharged outside the system.

The polymer squeezed and dehydrated with a conical squeezer is continuously supplied to the vent extruder, and the remaining water evaporates from vent port 3 and is discharged outside the system, leaving only the dried polymer in a molten state at the tip of the screw. being pushed out.

Although FIG. 2 shows an example of a screw-type device in which the present invention is effectively applied, it is needless to say that the device is not limited to FIG. 2 as long as it is a screw-type device that performs squeeze dehydration.

When recovering a polymer from polymer latex using a screw-type squeezing dehydrator, if vinyl M, coalescing pellets, and/or vinyl polymer beads are supplied simultaneously with the polymer latex, dehydration can be achieved in a stable manner. Although the reason for drying is not clear, it is believed to be due to the following two reasons.

(1) The coagulation of hard pellets and/or beads makes it easier for the solidified cake to undergo compression drawing, making it easier to drain water from the cake phase. (2) Compression drawing with a screw type It is assumed that the compression of the polymer → fusion → discharge of the encapsulated water occurs continuously, resulting in a complex force action.

In such systems, it is necessary for the screw to continuously transport the polymer, but stable transport by the screw is difficult due to the presence of water (which acts as a lubricant) discharged from the polymer phase. It is thought that.

The presence of hard pellets and/or beads serves to assist in stable transport of the screw.

The above-mentioned polymer latex used in the present invention is not limited in any way to the emulsifier, initiator, or other chemicals used in emulsion polymerization, and any chemicals used in normal emulsion polymerization can be used. It doesn't matter if it's something.

In addition, there are no particular restrictions on the type of coagulant or coagulation temperature that deactivates the emulsifier that has the effect of stabilizing the emulsification of latex. electrolyte inorganic salts and inorganic acids,
Acidic substances such as organic acids can be used.

As is clear from the above explanation, according to the method of the present invention, polymers with low residual moisture can be produced in an extremely stable state compared to conventional recovery methods using a screw-type squeezing dehydration/drying machine. MME can be recovered in a molten state.

The present invention will be explained in more detail below using Examples.

In addition, the number of parts in the examples indicates the number of parts by weight.

Example 1 A graft polymer was produced using the following polymerization recipe.

Polybutadiene latex (solid content) 65 parts styrene
24.5 parts acrylonitrile
10.5 parts tertiary dodecyl mercaptan 0.19 parts potassium persulfate
0.25 parts potassium oleate
1.6 parts pure water 120 parts Polymerization temperature 65°C Styrene, acrylonitrile and tertiary dodecyl mercaptan were mixed in advance and placed in a reactor containing polybutadiene latex, potassium oleate and pure water at a rate of 10 parts/hour. was added and reacted with stirring.

After the reaction was completed, the polymerization rate was measured and found to be 97%.

An attempt was made to recover the polymer from the obtained graft polymer latex in the following manner.

The recovery device used is of the type shown in Figure 2-1, and its specifications are as follows.

Cylinder inner diameter 65mm φ L/D 26 Screw rotation speed 30~50rIIT] The temperature inside the cylinder is adjusted to 200~50'Q7 by heating the die part to 220℃ and heating the cylinder part from the tip to the rear end.
) Heating was divided into 6 temperature ranges.

Cylinder temperature die section 220°C 1st temperature range 200°C 2nd temperature range 180°C (exhaust port is here) 3rd temperature range 150°C 4th temperature range 120°C 5th temperature range ioo°C 6th temperature range 50°C A recovery device with the above specifications (having a latex supply port and a drainage port) is arranged as shown in the process diagram in Figure 1,
The graft polymer latex obtained by the above emulsion graft polymerization was charged into a latex storage tank 1, and a 3% aqueous magnesium sulfate solution was charged into a coagulant storage tank 2, respectively.

On the other hand, a styrene-acrylonide copolymer produced by continuous bulk polymerization had a cylindrical shape (diameter 2.5 plate φ length 31117 mm).
1L) The pellets were charged into pellet hopper 5.

The composition and molecular weight of the styrene-acrylonitrile copolymer pellets are as follows.

Styrene/acrylonitrile ratio 72/28 intrinsic viscosity
0.56 di/gr Intrinsic viscosity is the intrinsic viscosity measured by dissolving in the solvent methyl ethyl ketone and measuring the temperature condition at 30° C. using a Usoperode viscometer.

Pump P-1 and pump P-2 pump 20 kg of graft polymer latex and coagulant aqueous solution, respectively.
The slurry mixture solidified at 90° C. was continuously passed through a vacuum filter 4 and the cake layer was continuously scraped out with a screw. , was supplied to the dehydrator 8.

The moisture content of the supplied polymer cake was 55%.

At the same time as starting the feeding of the cake, styrene-acrylonitrile copolymer pellets were added to the metering feeder 6 at a rate of 25k.
Feed was started at a rate of g/Hr.

The dehydrator 8 started rotating the screw at the same time as the supply of the polymer cake and polymer pellets started.

Since the recovered polymer in a molten state was discharged from the die,
The discharged polymer was cooled with a cooling bath 9, cut with a cutter 10, and continuously collected in the form of pellets.

Almost clear water was discharged from the gap at the rear end of the cylinder, and steam was discharged from the vapor exhaust hole.

The exhaust gas from the vapor exhaust hole was connected to a vacuum pump equipped with a trap, and was sucked and collected.

The conditions of the recovered polymer, water discharged from the rear end of the cylinder, and liquefied material collected from the vapor exhaust hole were as follows.

(1) Recovered polymer discharge rate 34 kg/Hr Condition Good uncolored polymer physical properties Volatile content in polymer 0.2% (Recovered pellets were heated at 180°C
(Weight loss after heating for 3 hours) Melt viscosity 3.7
) Isosomatic impact strength 20 kg / Steel style notched tensile strength 350 kg /crrt2 Tensile elongation at break 13 (2) Amount of water discharged from the rear end of the cylinder
8.4 ky/H Water-soluble solids 0.1 to 9/H Water-insoluble substances (mainly polymers) o, 2 kg 7H (3) Amount of liquefied substances collected from the vapor exhaust hole (mainly water and some Monomer) 3kVH Upper Example 1 Styrene-acrylonitrile copolymer latex (styrene/acrylonitrile ratio 70/30° solid content concentration 58
%) was latex blended with the butadiene-styrene-acrylonitrile copolymer latex prepared in Example 1 as follows.

Latex blend ratio phthalene-styrene-a/71) Ronitrile copolymer latex: 31.4 parts Styrene-acrylonitrile coelectrolyte latex: 68.6 parts Recovery of a polymer from this polymer latex was attempted in the following manner.

The recovery device was the same as in Example 1, and the temperature setting of the cylinder was also the same as in Example 1.

This recovery device was arranged as shown in the process diagram of FIG. 1, and the blended latex was charged into the coagulant storage tank 2, and a 3% aqueous magnesium sulfate solution was charged into the latex storage tank IK.

Graft polymer latex and coagulant aqueous solution were pumped to 62.9 9/H using pump Pl and pump P-2, respectively.
The liquid is sent to the coagulation tank 3 at a rate of r and 5.7 kg/Hr,
The slurry mixture solidified at 90°C is passed through a vacuum filter 4.
The cake layer was continuously scraped out with a screw and supplied to the dehydrator 8.

The moisture content of the supplied polymer cake was 43%.

At the same time as starting to feed the cake, the screw of the dehydrator 8 began to rotate.

Since the recovered polymer in a molten state was discharged from the die,
The discharged polymer was cooled in a cooling tank 9, cut with a cutter 10, and continuously recovered in the form of pellets.

However, compared to Example 1, surging was large and polymer occasionally vented up from the exhaust hole, and it was necessary to periodically remove vented polymer.

The conditions of the recovered polymer, water discharged from the rear end of the cylinder, and liquefied material collected from the vapor exhaust hole were as follows.

(1) Amount of recovered polymer discharged: 33.3 to 9/H Condition: The strands were foamed, the pellets were irregular, and the color tone was good.

Physical properties Volatile content in polymer 2.0% Melt viscosity 2゜9X10" poise (220'C
) Izotsu impact strength 21 to 9 cfrL/c7rL notch tensile strength 350 ky/cffl Tensile elongation at break 15% (2) Total amount of water drained from the rear end of the cylinder
18.5 kg/H water-soluble solids 0
．． 1 kg7H Water insoluble matter (mainly polymer) 0.5 to 9/H (3) Substances collected from the vapor exhaust hole Liquid matter (mainly water, monomer) 7 to 9/H polymer
1 kg/H Compared to Example 1, it can be seen that the shape of the obtained polymer was less uniform and contained more water.

Furthermore, if we compare the operability of the recovery equipment, the polymer recovery rate is 99% in Example 1, while it is 95% in Comparative Example.
The main reason for this is that when mechanical throttling is performed, a large amount of polymer escapes into the squeezed water, and that a large amount of polymer is accompanied by water evaporation in the vent hole.

This not only reflects the difference in the yield of the recovery equipment, but also the difference in the operability required to operate the recovery equipment, such as removing the polymer that vents up.

Example 2 Using the same recovery equipment and temperature conditions as in Example 1, a polymer was recovered from the same raw material latex.

As is clear from Table 1, which shows the processing speed of each raw material and the operation results of the recovery equipment, in Example 2-3, where a large amount of styrene acrylonitrile copolymer pellets were supplied, the resin temperature rose and the color tone of the resin worsened. Undesirable.

In addition, in Example 2-2 in which the amount of copolymer pellets is small, there is a large amount of polymer that vents up, and the operability is poor, indicating that it is desirable to supply an appropriate amount of copolymer.

Example 3 Styrene-acrylonyl copolymer beads (average particle size 700 microns) were produced by suspension polymerization.

The string size and molecular weight of the styrene-acrylonitrile copolymer are as follows.

Styrene/acrylonitrile ratio 75/25 intrinsic viscosity
0.54 d l/gr.
-1 was supplied in place of the styrene-acrylonitrile copolymer pellet.

The conditions of the recovered polymer, water discharged from the rear end of the cylinder, and liquefied material collected from the vapor exhaust hole were as follows.

(1) Recovered polymer discharge amount 34 to 9/H Volatile content 0.3% Shape Good uncolored polymer (2) Amount of water discharged from the rear end of the cylinder Discharge amount 2 Water-soluble solids 0. 3kg/H Water-insoluble solids (mainly polymers) 0°2kg/H (3) Material water collected from vapor exhaust hole 4 to 9/H Vent-up polymer Z Oky/H Example 4 Figure 2-3 An attempt was made to recover the polymer from the latex using the recovery apparatus shown in Figure 1 and arranged as shown in the process diagram of Figures 1-2.

The specifications of the recovery device are as follows.

conical squeezer Japan Steel Works SD’U-90 type machine Screw diameter: 90 mm φ x 21.6 mm φ The screw has an inclination angle of 10° at the top end.

The cylinder was divided into three temperature ranges, and the temperature settings were as follows.

Tip 1st cylinder 150'C 2nd cylinder 100°C Conical 3rd cylinder 50°C Vented screw Screw diameter 6511LrILφ
L/D 26 cylinder temperature settings are as follows: Die part 220°C 1st temperature range 2000C 2nd temperature range 180'C (exhaust port is here) 3rd temperature range
Temperature range: 150"C Fourth temperature range: 120°C Fifth temperature range: 100'C Sixth temperature range: 50°C (polymer supply port) The treated latex is a butadiene-acrylonitrile copolymer latex and a styrene-acrylonitrile copolymer latex. It is a mixed latex.

Butadiene-acrylonitrile copolymer latex is
It was obtained under the following polymerization conditions.

Initial preparation Number of parts Sodium Formaldehyde 0.3 Sulfoxylate Fe50 ・7H200,01 EDTA ・4Na 0.
1 Disproportionated sodium rosin acid 0.5 Butadiene
70.0 Acrylonitrile
30.0 tertiary dodecyl merkapukun
0.3 Water 165 Additional charge cumene hydroperoxide 0.15 Disproportionated sodium rosin acid 1.5 Water
25 Polymerization temperature 30-6
Polymerization time at 5°C: 5 hours On the other hand,
Styrene-acrylonitrile copolymer Heret (styrene/co'71) lonitnol = 75/25 by bulk polymerization
, intrinsic viscosity 0.56 d 1/gr ) and styrene-acrylonitrile copolymer latex (
Solid content concentration 58%, styrene**-acrylonitrile-
75/25, intrinsic viscosity 0.55 old/gr) was prepared.

Pump P-1 sends a predetermined amount of latex from latex storage tank 1, and pump P-2 sends a predetermined amount of coagulant aqueous solution from 3% magnesium sulfate aqueous solution storage tank 2 to coagulation tank 3.
The slurry is stirred and mixed and a certain amount of the slurry is supplied to the recovery device 6 using a waist pump P-3.

At the same time, the supply of polymer pellets from the styrene-acrylonitrile copolymer pellet hopper 4 to the quantitative feeder 5 is started.

The amount of water removed and the amount of evaporated water from the conical squeezer 6 and the vented screw 7 were checked, and the operational status of polymer recovery from latex was observed.

Table 2 shows the flow rate conditions and operation results.

From Table 2, the effect of the presence of hard styrene-acrylonitrile copolymer pellets on squeezing dewatering is clear.

A collection device was installed in the process shown in Figure 1-1 to recover the polymer from the α-methylstyrene-styrene-acrylonitrile copolymer latex.

The specifications and temperature conditions of the recovery device are as follows:
90mmφ Gui 2200G 1st cylinder 220°C 2nd cylinder 190°C (cylinder is screen)
3rd cylinder (variable throttle mechanism) 4th cylinder 150°C (cylinder is screen) 5th cylinder (variable throttle mechanism) 6th cylinder 100°C (cylinder is screen) yellow 7th cylinder 1.00°C (cylinder is screen) ,
ponomer supply port) The α-methylstyrene-styrene-acrylonidonol copolymer latex has a solid content concentration of 45% and an α-methylstyrene/styrene/acrylonitrile ratio of 50/25/25.
Also, the styrene/acrylonitrile ratio is 70/30, and the intrinsic viscosity is 0.70.
di/gr) was used at the same time.

Coagulant is implemented f! l! As in +1, a 3% aqueous magnesium sulfate solution was used, and the recovery conditions and results are shown in Table 3.

[Brief explanation of drawings]

FIG. 1-1 is a process diagram showing one example of the recovery process of the present invention. 1 is a latex storage tank, P-1 is a latex supply pump,
2 is a coagulant storage tank, P-2 is a coagulant supply pump, 3 is a coagulation tank, 4 is a vacuum filter, 5 is a polymer pellet or polymer bead hopper, and 6 is its quantitative feeder. T is a filtration water receiver, P is a tank. -3 is a pump for discharging filtrate water, P-4 is a vacuum pump, 8 is a polymer recovery device with a screw throttling mechanism, 9 is a gut 8 cooling bath, 10 is a cutter, 11 is a vent evaporative receiver tank, P- 5 is a vacuum pump. Figures 1-2 show another example of the recovery process of the present invention. 1 is a latex storage tank, P-1 is a latex supply pump,
2 is a coagulant storage tank, P-2 is a coagulant supply pump, 3 is a coagulation tank, P-3 is a coagulation slurry supply pump, 4 is a polymer pellet or bead hopper, 5 is a quantitative feeder thereof, 6
1 is a conical squeezer with a tilted cylinder, 7 is an extruder with a vent, 8 is an evaporative receiver tank, 9 is a cooling bath, 1
0 is a cutter, and P-4 is a vacuum pump that keeps the ventro vacuum. 2-1 to 2-3 are cross-sectional views showing examples of the recovery device of the present invention. FIG. 2-1 shows a recovery device having an aperture and deaeration port mechanism based on the screw compression ratio, where 1 is a polymer supply hole, 2 is a drain port, and 3 is a vent hole. Figure 2-2 shows a recovery device with a two-stage variable throttle mechanism, in which 1 is a polymer supply hole, 2 and 4.6 are screen parts, and 3
, 5 is a variable throttle part, and 7 is a solid barrel part. Figures 2-3 show an example of a recovery device that combines a mechanical squeezing screw and an extruder with a vent, in which 1 is a polymer supply hole, 2
3 is a screen portion, and 3 is a vent hole.

Claims (1)

[Claims] 1 (a) Vinyl polymer latex (b) Graft polymer latex obtained by emulsion graft polymerization of a vinyl monomer to a rubber polymer, and ←→vinyl polymer latex and rubber polymer latex and/or It is selected from a mixed polymer latex with a graft polymer latex obtained by emulsion graft polymerization of a vinyl monomer to a rubber-like polymer, and the polymer in the latex is hard at room temperature.
When recovering a polymer from a polymer latex that has the property of becoming soft or molten at a temperature of 00 to 300°C, the polymer latex is coagulated and then screwed together with vinyl polymer pellets and/or beads. A method for continuously recovering a polymer from a polymer latex, which is characterized by supplying the polymer latex to a type of squeezing dehydrator, performing dehydration and drying, and continuously taking out the polymer in a molten state from a die section at the tip of a cylinder.