JPH01225512A - Driving method for rubber-like polymer - Google Patents

Abstract

PURPOSE:To mix and rectify a molten material in an axis extension of a screw and manufacture a flat extruded material without burning or the like by mounting a breaker plate of special structure between a barrel and a die section of a biaxial screw extrusion dryer. CONSTITUTION:A breaker plate 3 is mounted between a die section 1 and a barrel 2. Guide wings 6 are provided vertically and laterally from the peripheral edge in an oblong space 5 of same shape as the inner shape of the barrel of said breaker plate 3, and both faces of said wings 6 are constituted of wing faces in parallel with a screw shaft. The wings are crossingly connected with each other, and crossing sections 7 are positioned on the axis center extensions of respective screws 4 of the biaxial screws. As the guide wings 6 of the breaker plate 3 are crossed at the ends of respective screw shafts, the axis core extensions of a molten material extruded from the screws 4 is guided at the crossing sections, and mixed with the surrounding molten material in a space encircled with wings 6. Therefore, a high temperature bar-shaped section required when the breaker plate 3 is not provided can by eliminated, and as the molten material is fed in the die section in the state of being sufficiently kneaded, a flat-shaped surface without any projection and recesses can be provided at the time of discharging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a method for drying a rubbery polymer using a twin-screw extruder, and more particularly to a method for obtaining a flat plate-shaped gel and a dried product. It is.

[Prior Art] A method of drying a rubbery polymer using a twin-screw extruder is used because the device is compact, requires a small installation area, and provides a dried product with a desired shape.

As an example of a twin-screw extruder, for example, JP-A-59-2146
As shown in Fig. 31, in order to dehydrate the raw material kra 11 at the feeding stage of the extruder, two screws that mesh with each other and rotate in opposite directions are inserted into a barrel provided with a dewatering slit at the bottom of the raw material feed section. , has been disclosed in which a die for extrusion molding is provided at the distal end outlet.

Depending on the nozzle shape of the extrusion die, extruded dried products can be obtained in various shapes such as granules and strips, but extruded strips are easier to handle in subsequent kneading operations and are compatible with factory automation. It is also convenient for doing so.

In order to extrude the melt into a strip, a wide rectangular nozzle is installed between the die part and the screw tip, as shown in Figure 4, in an oval area of the same shape as the inside of the barrel for kneading and rectifying the melt. A breaker with a large number of circular small holes (8) arranged in a distributed manner.
plate is attached.

[Issues to be Solved by the Inventionff11 However, when using the above-mentioned twin screw extruder, the temperature of the melt becomes higher than necessary due to the resistance caused by the breaker plate provided in the die, and depending on the type of material to be dried, it may be burnt. This caused unfavorable results in appearance and physical properties.

If the breaker plate is removed to avoid the temperature rise at the above points, burning of the dried material due to the temperature rise can be avoided, but the extruded material is First, the cross-sectional shape is not thick, but has a hilly shape with raised sides and a depressed center, which makes it difficult to move, stack, knead, and especially handle automated operations, making it unsuitable.

[Means for Solving the Problems] The inventors discovered that when the above-mentioned breaker plate is removed,
It was discovered that the positions of the bulges on both sides of the extrudate corresponded to the respective axial extension positions of the twin screws, and by installing a breaker plate of a specific shape, the flow state of the melt in the die section was changed, and the flow from the nozzle was changed. Obtaining flat extrudates! , : Successfully completes the invention C, :
It's arrived.

Thus, according to the present invention, a plurality of guide vanes each having a wing surface parallel to the screw shaft are provided in an elliptical or rectangular gap, and the guide vanes are arranged at least at a position corresponding to the screw shaft extension. A rubber-like polymer characterized by drying 1% of a lump-like polymer using a twin-screw extruder in which intersecting breaker plates are installed between a screw part and a die part. A drying method is provided.

That is, a breaker plate with a special structure according to the present invention is installed between the barrel and die part of a twin-screw extrusion dryer, and the melt is mixed and the T1 flow is performed at the axial extension of the screw. The extrudate is flat and has no sintering.

The tip of the twin-screw extruder is as shown in the longitudinal cross-sectional view of FIG. 1, and a prenicar plate (3) according to the present invention is installed between the die part (1) and the barrel (2). One embodiment of this breaker plate (3) is as shown in the front view of FIG.
Guide vanes (6) are provided vertically and horizontally from the periphery within the interior, and both sides of these guide vanes (6) consist of blade surfaces parallel to the screw axis, and the vanes are cross-coupled, and their intersections ( 7) is designed to be located on the axial extension of each screw (4) of the two-wheeled screw. Of course, the shape of the breaker plate may be one in which horizontal vanes and diagonal vanes intersect at the extension of the screw axis as shown in Figure 3, or it may be formed from diagonal vanes such as vertical vanes and horizontal vanes. However, at least the intersection of the vanes is required to be located on the axial extension of each screw. The number of vanes and the number of intersections between the vanes can be appropriately selected within a range that does not significantly increase the flow resistance of the melt.

The twin-screw extrusion dryer used in the method of the present invention may be any known twin-screw extrusion dryer, and depending on the type of gourd to be dried, a single screw, a left-handed screw element, a right-handed screw element, etc. may be used. A screw configured by combining an element etc. and a kneading disk may also be used.
The barrels also include feed barrels, standard barrels, pent barrels,
A dewatering barrel and the like are assembled in correspondence with the screw segments.

The method of the present invention is applied to drying various synthetic rubber crumbs. That is, it is suitable for drying crumb obtained by salting out and coagulating a polymer slurry by emulsion polymerization, and Kura 11 obtained by hot water treatment of a polymer cement by solution polymerization.As the rubber, styrene-butadiene rubber, nitrile rubber Butajengo 1% H isoprene rubber, Butajengo J%l
It is used for drying Go-11-kura l- such as Axorgo-11.

[Function] In the case of a two-wheel screw extrusion dryer, when molten rubber is introduced into the die section with the Plenical plate removed and extruded, the molten rubber leaving the screw kneading section is internally Due to the flow, the kneading action is not performed much, and a rod-shaped high-temperature part is formed, and when this part is discharged from the nozzle, it swells, and as a result, the center part becomes constricted.
It is thought to have a shape with two raised hills on both sides.

In the present invention, the guide vanes of the blade curve plate are:
They intersect at the part corresponding to the tip of the screw shaft, so the axial extension of the molten material extruded from the screw is divided at the intersection, and is separated from the surrounding molten material within the gap surrounded by the plate. mixed. Therefore, the hot rod-shaped part of the shaft center extension part as in the case without a breaker plate is eliminated,
Since it is sent to the die part as a well-kneaded melt,
The high-temperature rod-like portion disappears, and a flat plate-like surface without unevenness is obtained without producing any bulges or constrictions during discharge.

[Example] Hereinafter, the method of the present invention will be specifically explained using Examples and Comparative Examples.

Examples of the twin-screw extrusion dryer include a foot barrel, a dewatering barrel,
Marking consisting of standard barrel, pent barrel and vacuum barrel
A p-type extrusion dryer was used, and nitrile rubber (NBR) Kura 11 was used as the gono-like polymer.

The moisture content of the nitrile rubber crumbs supplied to the feeder of the extrusion dryer is approximately 50%, and most of the moisture in the crumbs is dehydrated in the dehydration barrel of Cura 11, and the remaining moisture and evaporated substances are sucked out in the vacuum barrel. It is removed and continuously extruded into a strip through a breaker plate and a die section, sent to a room temperature blower cooler, and cooled to become a dried material.

The breaker plate shown in FIG. 3 was used. A guide vane plate with an axial blade length of 33 n+m is provided in an oval space having a major axis of 245 rm and a minor axis of 133 mm, and the two vane plate intersections are located on the axial extension line of the two-shaft scrico.

Drying was carried out using this extrusion dryer under normal operating conditions. The average volatile content of the dried extrudate at the outlet of the cooler is 0.4-0.7%
The product has been thoroughly dried, and there are no burn marks on the product.The cross-sectional shape is as shown in Figure 5, and the thickness of the hilly parts on both sides is 25 mm.
+ms, the thickness of the central constriction was 241III11, and it had a substantially --like flat plate shape.

Comparative Example 1 The same extrusion dryer and nitrile rubber rubber 11 with the same moisture content as in the example were used.

A conventional breaker plate shown in FIG. 4 was used as the breaker plate. The thickness of the plate is 35 mm, and it has a total of 42 through holes of 61 TllIlφ in two circular sections.
They are distributed in two pieces.

The operating conditions were adjusted so that the volatile content of the dried product was 0.4 to 0.7%, the same as in the Examples.

The obtained dried product had a hollow or flat cross-sectional shape, but many burn marks were observed.

Comparative Example 2 The same extrusion dryer and nitrile rubber flannel with the same moisture content as in Example 1 were used.

Without installing a breaker plate, the die part was directly phosphorus bonded to the extruder tip barrel, and the operating conditions of the extruder were adjusted so that the volatile content of the dried product at the outlet of the blow dryer was 0.4 to 0.7%. It was adjusted.

As shown in FIG. 6, the cross-sectional shape of the dried product obtained is both f! 11th part thickness is 29mm, center part is 1811111
(7) It had severe unevenness.

[Effects of the Invention] According to the present invention, a flat product can be obtained by preventing the reduction in product Tq due to high temperature at the die part, which has occurred in plate-shaped extruded rubber since ft.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the tip of the extruder, FIG. 2 is a front view of a breaker plate applied to the present invention, FIG. 3 is a front view of another embodiment, and FIG. The figure is a front view of a conventional breaker plate, FIG. 5 is a sectional view of a dried rubber product in Example, and FIG. 6 is a sectional view of a dried rubber product in Comparative Example 2. (1)...Die part, (2)...Barrel, (3)...
・Breaker play), (4)...screw, (5
)...Gap portion, (6)...Guide vane plate, (7)...
Intersection, (8)... circular small hole. Patent applicant Nippon Shichion Co., Ltd. Toshiba Machine Co., Ltd.

Claims (1)

[Claims] 1. A plurality of guide vanes consisting of wing surfaces parallel to the screw axis are provided in the oval or rectangular gap, and the guide vanes intersect at least at a position corresponding to the screw axis extension. A method for drying a rubbery polymer, which comprises drying crumbs of a rubbery polymer using a twin-screw extruder equipped with a breaker plate between a screw part and a die part.