JPS6245044B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for processing viscous plastic and polymeric materials. Japanese Patent Application No. 52-91338 (Japanese Patent Publication No. 61-47684) filed on July 29, 1972, "Method and Apparatus for Treating Polymer Materials", invented by Zehev Tadmor, one of the inventors of the present invention, A method and apparatus for processing solid and viscous plastic or polymeric materials is disclosed. In this method, material is fed into an encircling passage formed by an annular groove rotatably mounted in close contact with the housing, and a block is disposed in the groove to impart movement relative to the groove surface. Retained in the groove and processed. The method and apparatus are suitable for conveying solid, molten or plastic plastic or polymeric materials, conveying viscous liquid materials,
Described as effective for changing molecular structure or microscopic or macroscopic structure by chemical reactions such as pumping or pressurization, mixing, compounding, dispersing and homogenizing materials, and removing volatiles and/or polymerization. ing. In the method and apparatus of the above-mentioned patent application, a protruding dam is disposed in the groove to form a material void on the leading end surface of the material in the running direction of the groove, and the plastic or polymer material being processed in the groove is removed from the plastic or polymer material. A port is inserted into the housing at the location where the volatile matter is received and discharged, and devolatilization processing is performed. Although some volatile removal may be accomplished by the rotary processor method described in the above-mentioned application,
Devolatilization efficiency is low because the surface surrounding the void is small. It is an object of the present invention to process viscous plastic or polymeric materials with a large surface-to-volume ratio in an enclosed passageway to efficiently transfer substances to or from the plastic or polymeric material. An object of the present invention is to provide a rotating groove processing apparatus and method. With this purpose and in accordance with the features of the invention:
The devolatilization or other mass transfer treatment of viscous plastic or polymeric materials in which two of the grooves are
Spreading the material in a thin layer on two simultaneously moving opposing walls, with a free space between the surfaces of the material, or from the material across the interface between the layer of material and the free space. A method or apparatus is provided in which a gas, vapor or other material is passed towards the material. The moving wall is operative to draw material from the inlet toward the spreader to form a layer, transport the material layer to accumulate in a pool, and discharge from the channel to the outlet. The invention will be explained by means of an embodiment of the device according to the invention with reference to the accompanying drawings, in which: FIG. The method and apparatus of the present invention have unique advantages in the following respects. That is, according to the invention, a body of material is delivered through an inlet into the space between two opposing surfaces forming part of an enclosed passageway, and the material is spread in a thin layer over said surfaces, and these The material layer on the wall of the groove is maintained in the center of the space between the layers as free space to ensure a high surface-to-volume ratio for effective mass transfer with the plastic or polymeric material. The central free space between can be used to process plastic or polymeric materials in such a way that gases or volatile substances can be received from or supplied to the material layer, or solid or liquid substances can be introduced into the material layer. . By simultaneously moving the two surfaces in one direction, the material is conveyed within the groove toward the outlet, abutting the end block, accumulating the material in a pool, and expelling it from the groove via the outlet. Additionally, in the method and apparatus of the invention, a spreader is positioned near the inlet to form a thin layer of viscous plastic or polymeric material on the side wall of the rotating element, so that the material is deposited as a thin layer. It is present for a long time and therefore can be sufficiently devolatilized from this material. An effective device for providing this motion (see FIGS. 1 and 2) consists of a rotor 10 rotatably mounted within a housing 14 on a drive shaft 12, the shaft 12 being mounted on an end plate of the housing 14. 1
It is pivoted on 6. The rotor 10 has an annular, preferably cylindrical surface portion 18 and at least one annular groove 20 defined on either side by spaced apart side walls 22 in the annular surface portion 18. has been done. Preferably, the groove has a wedge-shaped cross-section with the widest width on the outside;
Material feeding, uniform processing and cooperation with wedge-shaped spreaders are facilitated. Housing 14
has an annular, preferably cylindrical surface coaxial with and adjacent to the annular surface portion 18 of the rotor, the groove 2
0 to form an encircling annular passage. An inlet 26 is provided through the housing 14 for introducing plastic or polymeric material into the annular groove 20 from a suitable feeder for processing. Depending on the characteristics of the plastic or polymeric materials and the difficulty of controlling their feeding into the grooves 20, it will be obvious to use a suitable feeding device, such as a screw feeder, ram feeder, disk preheat feeder, etc. be. As best seen in FIG. 1, the inner surface 24 of the housing 14 is cylindrical around most of its circumference, but has a notch 28 adjacent the material entry 26 to the groove 20. This cut 28 is formed on the wall 3
0 has a width sufficient to extend over the cylindrical portion 18 of the rotor 10 to form an intake chamber 32, so that when the viscous liquid material is supplied to the inlet 26, the viscous liquid material is cylindrical surface 18 of the rotor, the surface of the wall 30 of the notch 28 reaches the position of the nip, where the surface of the wall 30 approaches the cylindrical surface 18 of the rotor. This action facilitates squeezing the viscous material into the groove 20. The illustrated spreaders 34 (first, third and fourth
Figure 2) shows a wedge-shaped block complementary to the wedge-shaped cross-section of the groove, extending through the housing 14 and extending through the groove 20.
is entering inside. The spreader is movable in and out of the groove to vary the gap between the sides 36 of the spreader block 34 and the groove walls 22. In the configuration shown, the spreader 34 extends in the inlet direction with a rounded edge 38 and a side surface 40 that flares from the edge 38 toward the side 36 to spread the material being processed. Two side walls 2 of the groove 20
2 Distribute on top. It has another structure, and the side wall 2
It is clear that a spreader with a variable gap between the two parts may also be used. The side walls 22 of the groove are compressed to the extent that the viscous material can be forced into the gap between the side 36 of the spreader block 34 and the wall 22 of the groove to spread the material in a thin layer and advance it over the wall. Preferably, this spreader is located close to the inlet 26 so that the forward drawing action increases the pressure. The central portion 44 of the groove 20, located forward of the spreader 34 in the direction of movement of the rotor groove 20, is kept free of plastic or polymeric material by the spreader 34, so that there is no material between the space 44 and the layer 42. thin layer 42 so that movement of
has a free surface exposed to a central free space 44. For example, volatiles in the plastic or polymer material migrate into free space and are drawn out of the channel via outlet 46 for devolatilization, optionally with the aid of vacuum means. Because of the large surface-to-volume ratio and the short distance the material must travel through layer 42 to reach the free surface, transfer operations such as devolatilization are extremely efficient. Mixing the material of layer 42 on the walls of the grooves to facilitate devolatilization or other mass transfer between central free space 44 and material layer 42
This can be achieved by disposing a mixing element 48 (see FIG. 5) to engage the layer 42 carried by the groove walls 22. The mixing element 48 shown in FIG. 5 is a bar or knife spreader parallel to the channel wall 22 and spaced a distance slightly less than the thickness of the layer 42 so as to leave a bank of material layer in front of it. Accumulation is effective to cause mixing within the bank 50 and to spread material from the bank 50 as a layer 52 on the surface of the trench wall 22 as it passes through it. Other mixing means such as pins, rods, etc. can of course also be used. Additionally, an inlet 54 is provided to open the free space 44 between the plastic or polymeric material layers 42 on the channel wall 22.
Materials may be introduced into the The substance introduced through this inlet 54 may be a gas that improves the flow and sweeping action on the material layer to aid in the removal of gases or vapors escaping from the surface, or a reagent that binds to the material layer, or It may also be a reinforcing material such as glass beads or reinforcing fibers, or other solids added to the plastic or polymeric material. The groove block 56 attached to the housing 14 is
The circumferential position from the inlet 26 is a complete one of the rotors.
Fitting into the groove 20 at a position that forms the main part of rotation,
An end wall 58 is formed for the annular groove 20 and the groove wall 2
2 and forms a scraper portion 60 in close contact with the scraper portion 2. Groove block 56 is complementary in shape to groove 20 and fits closely therein. The end wall 58 facing the annular groove 20 may be arranged radially or at any suitable angle depending on the material and process. Adjacent to and upstream of the groove block 56, ie, opposite to the direction of movement of the groove, there is a housing 14.
An outlet 62 may be provided through the. The groove block 58 scrapes and collects viscous liquid material that is advanced by the side walls of the groove and this material is deposited as a pool 64 abutting the end wall 58 of the groove block and the material generated within the pool. It is discharged from the groove 20 by the applied pressure. As shown in Figure 3,
The size of the pool is controlled to leave most of the central portion of the channel empty to allow material transfer to and from layer 42 on channel wall 22. In accordance with the principles set forth in the Tadmor application, the film or layer 42 on the channel wall 22 is related to the rate of ejection of material from the outlet 62.
The speed of the material passing through the spreader 34 is controlled to maintain the dimensions of the pool 64. Generally, pool 64 is maintained at a size that approximates the minimum required for sufficient pressure to be generated in the material of pool 64 by the pumping action of channel walls 22 to expel material from outlet 62. As fully described in the Tadmor application cited above,
Neglecting gravitational and inertial forces (centrifugal forces), the material flow is a constant temperature, laminar, stable, well-developed flow of a non-Newtonian fluid in the incompressible force law model. Assuming, the interrelationship of the feed and discharge rates of viscous liquid plastic and polymeric materials into the processing annular groove and the velocity of the groove walls for a given material property, groove temperature and geometry can be expressed by the following equation: be done. Q=πNHR ² d(1−α ² )−(H ^s+2 Rd ^1−s (α ^1−s −1)/2 ^s+1・(
s-1) (2+s) m ^s ) (dp/dθ) ^s Q = Volume flow rate (in ³ /sec) N = Period of rotation of groove (rps) Rd = Outer radius of annular groove (in.) Rs = Inner radius of the annular groove (in.) α=Rs/Rd H=Width of the annular groove P=Pressure (psi) θ=Angle (radian) dp/dθ= ^P out− ^Pin /2πφ = Angular pressure gradient (psi /rad.) Pout = outlet pressure Pin = inlet pressure φ = circumferential portion from inlet to outlet s = 1/n'force law' experimental parameters of model fluid η = mr〓 ^n-1 η = non-Newtonian Viscosity (lbf sec/in ² ) m = experimental parameter (lbf sec ⁿ /in ² ) n = experimental parameter r = shear rate (1/sec) In the above equation, the first term on the right side is 'dragging flow'
(drag flow), and the second term is 'pressure flow'. This formula also applies to Newtonian fluids, where s=n=1 and m=u are Newtonian viscosity. The operating conditions and physical settings of the apparatus according to the invention for generating a desired pressure at the outlet and for processing viscous plastic materials at a given speed are such that, for a disc speed N, the viscous material at a desired speed is First calculate and determine the distance from the channel wall to the side of the spreader that is necessary to form a film or layer of the thickness to be delivered. The thickness of the film or layer on the channel walls preferably ranges from 0.001 to 0.01 inch. This thickness is calculated using the following formula. Q=πD ² (1-α ² )2δN/4 where Q is the volumetric flow rate (in ³ /sec) and D
is the outer diameter (in.) of the annular groove, and α is the inner radius Rs (in.) relative to the outer radius Rd (in.) of the annular groove.
is the ratio Rs/Rd, and N is the period of rotation of the groove (rp
s). By calculating the combination of N and δ that is effective to deliver the material at the desired velocity and pressure to spread the material onto the groove walls by the spreader, we now know that for each value of N, The angle θ of the melt pool that provides the desired discharge pressure is determined from the equation of the Todmor application above. Typically, the combination of film thickness δ and groove rotational speed N is selected to provide optimum mass transfer between the free space within the groove and the film or layer of material on the groove walls. The main area between the spreader and the front of the melt pool is held open. Materials that can be treated by the method and apparatus of the invention are normally liquid or can be converted to a viscous liquid by heat, mechanical energy or diluents for treatment; All plastic and polymeric materials have sufficient stability under the conditions to avoid serious deterioration. Examples of such materials include, but are not limited to, polyolefins (e.g., polyethylene, polypropylene), vinyl chloride polymers (e.g., polyvinyl chloride), fluorine-containing polymers, polyvinyl acetate group polymers, acrylic group polymers, Styrene-based polymers (e.g. polystyrene), polyamides (e.g. nylon), polyacetals, polycarbonates, cellulose-based plastics, polyesters, polyurethanes, phenolic and aminoplastics, epoxy-based resins, silicone and inorganic polymers, polysulfine-based polymers, various natural-based polymers, There are thermoplastic, thermoset, and elastomeric polymeric materials, such as analogs thereof, and copolymers of these with each other, blends with solvents, diluents, or other solid or liquid additives. Chemically reactive substances, such as materials or mixtures thereof, which form viscous liquid polymers at certain stages of production and at holding temperatures in the grooves, are fed into the apparatus for reaction and processing within the grooves. You may go. The temperature of the material being fed and processed within the device can be controlled to determine the viscosity and flow properties of the material being processed. Examples will be described below to facilitate understanding of the present invention; however, the present invention
It should be understood that there are no limitations as to material, temperature or other details. Example The device was assembled into the apparatus shown in FIG. 1 at the angle shown in FIG. 6. That is, the inlet 26 is in the direction of rotation of the rotation groove.
50°, and the front surface of the spreader 34 is located 10° in the rotational direction from the edge of the inlet 26;
The outlet 62 extends for an extent of 35 degrees in front of the groove end block 56, which occupies an extent of 20 degrees. Rotor 10 has an outer diameter Rd of 7.5 inches
and an inside diameter Rs of 3.75 inches. The groove has a wedge-shaped cross section and the gap width of the groove is 0.5 inches. The inlet 26 of the device housing is connected to a conduit which receives molten low density polyethylene at a temperature of 400° at a rate of 250 lbs./hr. The processing equipment is required to deliver polyethylene at a pressure of 150 psi after devolatilization. The spreader 34 is wedge-shaped, complementary to the cross-section of the groove 20, and is adjustable inwardly and outwardly to adjust the clearance between its sides 36 and the wall 22 of the groove 20. 0.05 inch of spretzer 34 from the groove wall,
Three independent experiments were performed, separated by 0.100 inches and 0.125 inches, to form three different thicknesses of polyethylene film on the channel walls. In calculating the speed N of the grooved rotor, the density of the polyethylene was assumed to be 50 pounds per cubic foot, and the viscosity of the molten polyethylene was calculated using the following formula. η=mγ〓n where m=1lb/sec.0.5/ ^inch2 , n=0.5 From the groove rotor speed determined in this way,
Substituting the determined value into the formula described in Tadmor's application,
The melt pool angular range θ required to produce the desired 150 lbs discharge pressure was calculated. I get the following result:

[Table] If the spretzer gap δ is 0.05 inch, the melt spool angle θ may be 23°, so that most of the groove in front of the spretzer 34 is carried on the wall 22 for devolatilization. There was no molten material except for the film or layer 42, yet a pool of this length was sufficient to provide a discharge pressure of about 150 psi.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional elevational view of a processing apparatus according to the present invention, taken along a line in FIG. 2 parallel to the axis of rotation of a rotor of the apparatus. FIG. 2 is an elevational view of the cross-sectional end taken along the line - of FIG. 1 perpendicular to the rotational axis of the rotor. FIG. 3 is a developed view of a cross-section of a rotor groove cut along a circle of a predetermined radius, showing the movement of material within the groove. FIG. 4 is an elevational view of a section taken along line - in FIG. 1 and viewed in the direction of the arrow, showing the relationship of the spreader element to the wall of the groove. FIG. 5 is a developed view of one side of the groove cut by a circle with a certain radius;
Figure 3 shows the operation of the mixing element on the material layer conveyed by the walls of the groove. FIG. 6 is an illustrative sectional view showing the relationship between the rotational directions of the elements of the processing device. DESCRIPTION OF SYMBOLS 10... Rotor, 12... Shaft, 14... Housing, 20... Annular groove, 22... Groove side wall, 26... Material inlet, 34... Spreader, 42... Material layer, 44
...Central free space, 46, 54...Port, 48...
Mixer, 56...Block member, 64...Pool, 6
2...Exhaust port.

Claims (1)

[Scope of Claims] 1. A circular rotating element with an annular groove formed by opposing side walls, a circular rotating element arranged coaxially with the rotating element and covering the outer periphery of the annular groove to define an enclosed annular passage. a fixing element with an annular surface member forming an inlet for feeding a viscous plastic or polymeric material into the fixing element; rotating a rotating element to displace said material circumferentially from the inlet of the annular passageway; means, an outlet for discharging material disposed on the annular surface member of the fixation element circumferentially a distance constituting the majority of one complete revolution from the inlet in the direction of rotation of the annular groove, and an outlet proximate to the outlet; Processing of viscous plastic and polymeric materials having a blocking member mounted in position and extending into an annular groove to substantially occlude said groove and directing said material delivered by rotation of a rotating element to an outlet. The device comprises a spreader 34 arranged near the inlet 26 of the fixing element 14 and extending over substantially the entire depth of the annular groove 20, the spreader corresponding to the cross-sectional shape of the annular groove. having a cross-sectional shape and a width slightly less than that of the groove so as to form a relatively narrow gap between its side wall 36 and each side wall 22 of the groove, and of the annular surface member 24 of the fixation element. Between the outlet 62 and the spreader, there is at least one passage communicating with the outside of the device.
Apparatus for processing polymeric materials, characterized in that two ports 46, 54 are provided. 2. A circular rotating element with an annular groove formed by opposite side walls, an annular surface member disposed coaxially with the rotating element and covering the outer periphery of the annular groove to form an enclosed annular passage. an inlet for feeding a viscous plastic or polymeric material into the fixation element; means for rotating a rotating element to displace said material circumferentially from the inlet of the annular channel; rotation of the annular groove; an outlet for discharging material disposed on the annular surface member of the fixation element circumferentially a distance of the majority of one complete revolution from the inlet in the direction; An apparatus for processing viscous plastics and polymeric materials having a blocking member extending into a groove to substantially occlude said groove and directing said material conveyed by rotation of a rotary element to an outlet. A method of processing a material, the method comprising: feeding said viscous material into said annular passageway through said inlet 26;
A spreader 34 is disposed near the side wall 36 and extends substantially the entire depth of the annular groove 20 with a slight spacing therebetween. Forming thin layers of said material and leaving spaces 4 between these layers
4 and also an annular surface member 24 of the fixation element.
at least one port 46, 54 provided between the outlet 62 and the spreader and communicating the passageway with the outside of the device for discharging material from the space or supplying material into the space; A method for processing polymeric material, characterized in that the material is then discharged from an outlet by means of the blocking member 56.