DE1906630B2 - METHOD AND DEVICE FOR THE PRODUCTION OF CELL-SHAPED BARS FROM THERMOPLASTIC RESIN - Google Patents

Description

1 2

The invention relates to a method and a front can be rotated on a solid surface until

Direction for producing cell-shaped rods from thermal its surface has solidified to such an extent that it has become

thermoplastic resin with essentially circular under its own weight no longer deformed,

shaped cross-section by extruding a through-expediently, the direction of rotation of the

kneaded mixture of thermoplastic resin 5 rod reversed at least once,

and a foaming agent at elevated temperature By the measures of the method according to the

door and cooling the extruded molding. Invention prevents the rods from

For the production of cellular objects, such as those deformed under their own weight at this time.

Rods, is usually a so-called extruder, which would take place if the rods after the

Foaming process used, in which a mixture would be cooled down in a stationary state,

a thermoplastic resin; and a show stick

with heating in an extruder with a circular cross-section without complicated apparatus.

kneads and then with simultaneous expansion devices and with high extrusion

dieren is extruded, whereupon the extruded form speed. The procedure can save on

ling is cooled. As is known, this 15 solid rods is also carried out on hollow rods with essentially

Cooling, for example, rod-shaped briquettes with borrowed circular cross-section applied

Help from water (SPE Journal 19, page 397 [1963].

and 20, p. 1093 [1964]. When using the, the method is particularly advantageous for the

Water cooling method for cellular rods, special production of rods with a diameter

that is with those with a large diameter, the 20 is larger than 10 mm and an average

However, the cooling effect is strongest at the bar's upper specific weight less than 0.6. The bars can

surface, so that the rods are often deformed and continuously extruded, whereupon they

the cell diameter in the rods is different then adjusted to the appropriate length before cooling

grows big. In addition, with this method a lot of cuts will be made, for example 10 to 400 cm

times the foaming is interrupted prematurely, so 25 can be. Now the cooling has to be reduced

that the briquettes are started to rotate higher than the desired rotation on a solid surface,

Preserve density. When using air cooling methods or before the surface of the molding becomes too

methods in which the water cooling begins to solidify for a longer period of time. The one required for rotation

Air cooling precedes, although a full time will depend on the temperature of the extruded product

Foaming achieved, but could also mix with the help of 30 and the temperature of the cooling air as well

These methods result in a deformation of rod-shaped the diameter and the specific weight of the

Moldings are not avoided. Rods. Usually the cooling time required is

In order to deform cell-shaped tubes in the range of 10 seconds to 10 minutes, before-

to avoid cooling down, take off between 30 seconds and 5 minutes,

cool according to US Pat. No. 3,299,192,35. The speed of rotation is greater than

by rapid quenching immediately after the end of 10 rpm, particularly preferably greater than 100 rpm,

If the tubes come out of the extruder mouthpiece with no possibility of deformation around the rods

With the help of a ring nozzle and a tubular interior under its own weight. With bars

nozzle, through the coolant with larger speed - smaller diameter and larger specific

speed is blown onto the surface of the molding, 4 ° weight may reduce the rotational speed

so as to be an immediate solidification of the surfaces. The rotation can be continuous or discontinuous

after the molding has emerged from the extruder, and does not need to be carried out until

to effect mouthpiece. Such a process must be carried out for complete consolidation of the rods,

but calls for increased expenditure on equipment because it is sufficient if you can rotate until

The form of coolant nozzles and the rods connected to them are no longer under their own weight

Coolant fan and is only used for tubular deforming.

Hollow bars usable. In addition, it goes without saying that the extruded Ge process can also be used for this a deformation of the molding does not mix the thermoplastic resin and one to be excluded, at least if there are additional methods known per se during the foaming agent individual holes in the ring nozzle, some substitutes such as pigments, fire retardants, or clog up completely, since the coolant is then filled with fillers, plasticizers or the foaming under various points on the surface of the molding with supportive agents or agents that regulate the cell size different pressure. contain.

The object of the invention was therefore to provide a process The solid used for the present process

and a device for the production of cell-shaped 55 surfaces on which the molding during cooling

Rods made of thermoplastic resin, lens rotates, can be flat, curved or inclined and

those without additional coolant and with the combination of a rotating roller or an endless one

multiple apparatus measures work can consist of volume. The material of these solid surfaces

and a deformation of the circular rod cross- can be metal, wood, plastic, paper, a fabric,

Prevent cutting. 60 be ceramic, clay, concrete or asbestos. Given-

This method according to the invention for the fall can increase the temperature of the solid surfaces

cell-shaped rods made of thermoplastic material should be set to a certain value in order to prevent

Resin with a substantially circular cross-section so that the extruded moldings adhere,

by extruding a thoroughly kneaded mixture thermoplastic resin and an additional coolant are supported, for example in the case of increased temperature and cooling, use air, nitrogen or a cooling liquid,

of the extruded molding is characterized by the fact that the rods are drawn onto the rods as they rotate.

net that the molding is brought while cooling. For example, cold air can be

3 4

or blow cooling water over the solid surfaces. Fig. 16 is a plan view of a roller cooling unit.

th or, if these are designed like a jacket, direction,

pass through this. Fig. 17 is a vertical section along the

The device according to the invention for through lines and arrows XVII-XVII in F i g. 16,

The process can be carried out in different ways.

forms be, provided that they are a rotation of the form in which a cellular object with the help of

Briquettes are transported on a fixed by compressed air while cooling,

Area permitted. 19 is a plan view of an endless roller

In one embodiment, this device has cooling device and

tion a system of at least two alternately in Fig. 10. 20 a vertical section through the in

opposite direction inclined surfaces as well as Fig. 19 shown device along the lines and

Devices for deflecting the molding of arrows XX-XX.

one on the other surface. In another example. 1 is a cellular extruded rod 1

As a guide, the device has a top with a fixed plate 2, in FIG. 2 a cellular

Positioning surface for the shaped bodies rotating 15 extruded rod with two rollers 3 and in F i g. 3

Cylinder, a ring substantially equal to one - an extruded cellular rod 1, a solid one

at the other, at a distance from the cylinder plate 4, a transfer plate 5 and a roller 6

surface-mounted guide rollers, two shown.

It is advantageous to use a rotating device attached to the disks and drive means, which are able to continuously treat the extruded object, the cylinder and the disks in the underlying object. Also it is to drive different direction. In another as in FIG. 3 is shown, possible, two fixed embodiments, the device has an upward or movable flat or curved plate to be displaced surface for the moldings forming endless turning and the distance between the plates so as to adjust several substantially equal to each other that the cellular rod is adjusted in thickness during the spaced apart, at a distance from the conveyor belt upper cooling,
surface arranged guide rollers, two guiding rollers can also be supported in the case of the use of two guiding rollers, on both sides of the conveyor or more plates, these be mounted in such a way that a belt arranged endless plates and drive point of a point in a cell-shaped rod, of the devices that the conveyor belt and the endless 30 protrudes on a horizontal plane, drive themselves on plates in different directions. a straight line or a desired one. Finally, yet another embodiment has a figure, such as a zigzag shape or a triangle, a system of rotating rollers whose counter-shape forms.

lateral distance smaller than the diameter of the Now the embodiments according to the

Is, as well as drive devices, the ₃₅ invention in detail with reference to the

Drive the rollers in the same direction of rotation. Figures 4 to 8 described. The reference number 1

These embodiments of a device are referred to as a cellular rod, 2 'referred to

Carrying out the method according to the invention an inclined plate and 2 "a plate that is

are explained in more detail by the drawing. In this reverse direction how the plate 2 'is inclined. the

mean 40 plate can be flat or curved, corrugated or

F i g. 1 to 3 schematic representations can be designed in different stages, they can also be extended

which shapes of cooling devices have, porous, grid-like or louvre-like

Fig. 4 is a schematic representation of a grain. It preferably has a width

bination of inclined surfaces, less than 5 m and a length of 50 cm to

F i g. 5 a perspective view of the training ₄₅ 10 m. Expediently, age-

management form according to FIG. 4, renal plates used. The mechanism with

F i g. 6 a schematic representation of the behavior of an extruded rod from the plate 2 'to the At least one cell-shaped rod in the one shown in FIG. 4 next plate 2 "is dispensed is more desirable Apparatus, measured a system shown in FIG. 4 is shown and

F i g. 7 and 8 are schematic representations of two 50 rolling the extruded rod 1 through its inertia

other embodiments of the device, and then naturally reversed, with avoided

F i g. 9 is a front view of a cylindrical den that a deviation in the path of the

Cooling device, extruded rod 1 occurs. As in Fig. 7 shown

F i g. 10 a vertical section through the front, a baffle plate 10 can be provided around the

direction according to FIG. 9 to deflect along the lines and arrows 55 extruded rod 1, or it can

len X-X, other systems are used, the other powers

11 shows the representation of a section which is used as the force of gravity. You can

a guide roller section and an intermediate dimension according to the arrangement of the plates.

section in the device according to FIG. 9 shows to be chosen. In addition, the mentioned impact

F i g. 12 is a plan view of another embodiment plate 10 made of an elastomer, exemplary form of the device in the form of an end-wise one made of rubber, sponge material or springless Tape, material to elastically remove the extruded rod 1

F i g. 13 is a vertical section along the link. A part of the device can also be used

Lines and arrows XIII-XIII in FIG. 12, mechanism to reverse the

14 is a plan view of another cooling rod 65 extruded using a different force than

device in the form of an endless belt causing gravity and also, as in FIG

FIG. 15 shows a vertical section along FIG. 8, possibly driven rollers

Lines and arrows XV-XV in Fig. 14. 11 with a band 12 in a certain fixed

Distance from a surface 2 'is provided to allow for a fairly precise thickness adjustment of the extruded Rod 1 to effect.

In Fig. 5 is a perspective view of the FIG. 4 reproduced embodiment shown. An extruded rod is delivered to the system at point 7, from where it runs along face 2 ' rolls and falls on surface 2 ". Then, due to its inertia, it rolls a little further, then holds on its gravity increases and reverses, then rolls down along the surface 2 "and falls onto the solid Area 2 '". This continues by repeating the described rolling, falling and turning back until to the surface 8, during all of which the rod is cooled. At 9 the staff becomes removed from the device.

The F i g. Figures 9 to 15 of the drawings show devices with one provided with a guide Mechanism which has the function of moving the cellular rods along the surface of a itself rotating roller or a moving endless plate at a speed that on the speed of the surface of the rotating roller or the moving endless one Plate is different. The distance between the guide and the plate can be greater or less than be the diameter of the cellular rod to be treated.

In Figs. 9, 10 and 11, a is on a specific Length of cut cellular rod placed on the surface of a drum 13 before the surface of the cellular rod is solidified. The drum 13 is driven with the aid of a motor 17 rotated over a chain.

The drum 13 is contacted by intermediate rollers 14 at various points on its circumference. The intermediate rollers 14 are contacted by guide rollers 15 on their surfaces, and so the The rotation of the drum 13 is transmitted to the guide rollers 15 via the intermediate rollers 14. The direction of rotation and the peripheral speed of the drum 13 are the same as that of the guide rollers 15. Their rotation is transmitted by friction to the cell-shaped rods, so that they rotate.

Disks 16, which carry the intermediate rollers 14 and the guide rollers 15, are made with the aid of a Motor 18 rotated via a chain. Thereby, the intermediate rollers 14 and the guide rollers 15 become also rotated independently of the drum 13 with the aid of the disks 16.

In this embodiment, the intermediate rollers 14 and guide rollers 15 rotate around the Drum 13. By varying the speed of rotation thereof, the amount required for cooling can be increased Time to be selected as desired.

The construction of the intermediate rollers 14 and guide rollers 15 is simple and their shafts become supported by plain bearings and roller bearings. The intermediate roller 14 is preferably made of rubber or is covered with rubber to reduce the coefficient of friction with the drum 13 and the guide roller 15 to increase and to small deviations in the alignment between the guide rollers 15 and the drum 13 to balance.

If air is the coolant, the cooling time required here is usually between 10 seconds and 10 minutes, preferably between 30 seconds and 5 minutes.

It is useful to use a motor that is connected to a reduction gear or some other device is set up for speed regulation. In addition, since the zeü-shaped rod on the Drum can stick, if the temperature of the drum is too high, its inside is preferred cooled, e.g. B. with water.

In Figs. 12 and 13 is an embodiment shown using an endless plate.

ίο The conveyor belt 19 is in the by the inner The direction shown in the arrow in FIG. 13 is moved with the aid of a motor 21. An extruded cellular Rod 1 is placed on the conveyor belt and rotated by friction with the conveyor belt. Guide rollers 15 are shown in FIG. 3 by the arrow pointing to the right above the conveyor belt 9 Moved direction, they are supported by support plates 20.

The conveyor belt 19 can be made of any

ao material such as steel, cloth, or rubber, but rubber is the most common from the standpoint of friction preferred. The support plate 20 can be provided with the aid of a sprocket using a conveyor chain be moved, which is provided with a clutch.

In the embodiment according to FIGS. 14 and 15, the cellular thermoplastic rod 1, the cut to a certain length, placed on the endless plate 19 before the surface of the rod has solidified. He gets into the space between the endless plate 19 and the guide rollers 15 and is at the same peripheral speed as the endless plate 19 to Brought rotation. The guide rollers 15 also rotate by friction with the cell-shaped rods 1. The guide rollers 15 rotate in principle around the endless plate 19, and by varying the Speed of rotation, the time required for cooling the bars can be selected as desired will.

As mentioned above, the guide rollers 15 are free to rotate by friction with the cellular ones Rods, but they can also be set in rotation, for example, via an intermediate part or put into forced rotation. In certain situations it is also possible to use the cellular The rod can only be moved by moving the endless plate, the guide rollers not rotating need to be moved.

In the embodiment according to FIGS. 16 to 20 rollers rotated in the same direction form the solid surfaces for the cell-shaped rods and are shown in FIG arranged in such a way that the distance between the adjacent rollers is smaller than the diameter the bars is.

In Figures 16 and 17, a cellular thermoplastic Rod 1, cut to a certain length, to a space between the rollers 3 delivered with diameters of 10 to 100 mm, the rollers being positively driven in rotation be moved.

As shown in Figs. 16 and 17, there are several such rollers 3 are provided, and the rollers are interconnected with the aid of a chain and with the aid of Chain sprockets connected and driven together with the aid of a motor 24. Hence the direction of rotation of the rollers 3 necessarily the same. The rotation of the rollers 3 is due to friction transferred to the cellular rods.

As shown in Fig. 18, the cellular Rod 1, which lies between the roller 3 and the adjacent roller 3 ', with cooling during a certain Rotated duration. The cell-shaped rod is then rolled onto an adjacent pair of rollers the mechanism as in FIG. 18 convicted. This is done by compressed air blowing in a suitable direction is blown discontinuously through the nozzle 23 with a suitable number of openings. These Nozzle is connected to an air supply, not shown, and under the space between the rollers appropriate. This procedure is repeated until the cellular rod is to the required extent is solidified. The diameter of the openings of the nozzle is expediently 0.8 mm, the space between them between the openings 10 mm, and the angle of the nozzle is expediently 45 °.

In Fig. 18, the direction of rotation of the roller 3 is opposite to the direction of advance of the cellular Bars, but the two directions can also be the same.

Instead of using compressed air, the cell-shaped rods can be moved from a pair of rollers to the others are transferred, for example by pushing off the rods with a lever-like part that is attached to the same place of the cell-shaped rod attacks where the compressed air is inflated. Another Method uses an endless roller as shown in Figs. 19 and 20, with the cell-shaped rod 1 is conveyed further with the help of a transfer roller 3 itself.

In Figs. 19 and 20, the endless belt becomes 19. In Figs is continuously moved in the direction shown by the arrow pointing to the left with the aid of the motor 21. Rollers 3 are supported on support plates 20, and there the opposite ends of the rolls are in contact with the belt 19, they will be at the same speed as this belt set in rotation. The support plates 20 are continuously driven by a motor 22 in the moved by the direction shown by the right arrow to move the reels.

The cellular rod 1 is delivered to the space between the above-mentioned rollers and while it is rotated by friction at the same speed as the rollers will. The material used for the belt 19 is preferably rubber and the drive for the belt 19 a conveyor chain is preferred. It is also desirable that the speed of the tape and the speed of the support plate is about 10 meters per minute and about 0.5 meters per minute, respectively.

An important feature of the cellular rods obtained according to the invention is that their cross-section is essentially perfectly circular. Because the surface of the cellular rods is very smooth and stable Dimensions, they can be used for various purposes without post-treatment, by you simply sneeze them to the desired length. Especially when the cell-shaped rods are made as described above, their diameter can be in can be precisely controlled within a range of ± 0.2 mm, and therefore such a cellular rod can be used after simple cutting for disc seals which require great precision and for which cork washers were previously used. The rods can also be used as a heat-insulating material or lightweight building material can be used. Since they can also be colored as desired, they can be used as a Jewelry and toys are used. The invention is illustrated by the following examples further explained.

example 1

A composition of 100 parts by weight of low density polyethylene (density 0.92 g / cm ³ )

ίο and 1.5 parts by weight of p-toluenesulfonyl hydrazide was kneaded mm at 14O ⁰ C using an extruder with a single screw having a diameter of 65 and extruded into a cellular rod. The cellular rod was then rotated at 200 rpm by the method shown in Fig. 3 to undergo size reduction, and then allowed to cool.

This procedure resulted in a cellular rod with a diameter of 25 ± 0.1 mm, an aspect ratio greater than 0.99, a specific gravity of 0.42, a cell diameter greater than 200 microns, and a uniform and smooth surface. When the rod was cut to a thickness of 2 mm, the disks had good sealing properties. When it was used for disk seals for a crown cap, it could satisfactorily cope with an internal pressure of 8 kg / cm ² in a bottle.

On the other hand, if the same cellular rod was extruded under air cooling without rotating, the axis ratio of the rod was only 0.80 to 0.83, and when the rod was rotating at 5 revolutions per minute was rotated, it was 0.85-0.88. Accordingly, in these cases the cross-section was elliptical, and besides, the surface was somewhat uneven, and the rod too hard to be readily used as a seal to be used.

Example 2

A composition of 100 parts of high density polyethylene (density 0.95 g / cm ³ ) and 1.2 parts of azodicarbonamide was kneaded using a single screw extruder having a diameter of 65 mm and was kneaded at 200 ° C into a cellular rod extruded, and this cellular rod was made according to the method shown in FIG. Rotate the method shown in Fig. 3 at 150 rpm for two minutes and then cool.

In this process, a cellular rod with a diameter of 30 ± 0.5 mm was obtained, an axis ratio greater than 0.98. a specific gravity of 0.21, one cell diameter less than 400 microns and an even and smooth surface.

On the other hand, when the same extruded rod was air-cooled without rotation, it was Axial ratio 0.78 to 0.81. If the rod was allowed to rotate at 5 rpm for 2 minutes, that was Axis ratio 0.83 to 0.91. When the same molding was cooled in water of 30 ° C, became he is badly deformed.

Example 3

A composition of 100 parts of polyethylene (density 0.93 g / cm ³ ), copolymerized with 14% vinyl acetate, 1.5 parts of p-p'-oxybisbenzenesulfonyl

109 527/361

hydrazide, 0.1 part citric acid and 0.5 part sodium bicarbonate was made using a single diameter screw extruder kneaded by 90 mm and extruded at 150 ° C. The cell-shaped rod thus obtained became open cut a length of 600 mm and to the in F i g. 5 dispensed apparatus shown, the of The cell-shaped rod delivered to the apparatus was cooled with water at 30 ° C. for about 5 minutes.

This procedure resulted in a cellular rod with a diameter of 30 ± 3 mm, an aspect ratio greater than 0.98, a specific gravity of 0.43, a cell diameter less than 200 microns and an even and smooth surface. When the baton is on was cut to a thickness of 2 to 3 mm, the disks had good flexibility and were suitable for use as disc seals for crown lids.

Example 4

A composition of 100 parts of polyvinyl chloride, 50 parts of dioctyl phthalate, 10 parts of azodicarbonamide and 3 parts of stabilizer was dry blended and heated at 200 ° C using a Extruders with a single screw and a diameter of 90 mm. The so obtained cell-shaped rod was allowed to run for 2 minutes at 200 rpm using the method shown in FIG. 9 apparatus shown rotate and cool in air to form a cell-shaped rod with a diameter of 28 ± 0.2 mm, an aspect ratio of more than 0.98, a specific gravity of 0.48 and a medium one Cell diameters of around 50 microns and with an even and smooth surface. When this article was cut to a thickness of 2 mm, disks with a good one were obtained Flexibility and excellent properties for disc seals for crown lids.

Example 5

A composition of 100 parts of isotactic polypropylene (density 0.91 g / cm ³ ), 0.3 part of stabilizer, 0.5 part of azodicarbonamide and 0.5 part of Ν, Ν'-dinitrosopentamethylene tetramine was prepared using a single screw extruder and 65 mm in diameter was kneaded and extruded at 205 ° C, and the cell-shaped rod thus obtained was rotated at 100 rpm for three minutes by means of the apparatus shown in FIG 0.1 mm, a specific gravity of 0.53, an aspect ratio greater than 0.99, an average cell diameter of about 100 microns, and a uniform and smooth surface. The article was light and had excellent strength and was useful as a building material.

Example 6

A composition of 50 parts of low density polyethylene (density 0.92 g / cm · ¹ ), 50 parts of high density polyethylene (density 0.96 g / cm ^{: i} ) and 2.0 parts of p, p'-oxybisbenzenesulfonyl hydrazide was kneaded and extruded in a single screw extruder of 90 mm in diameter at 160 "C, and the resulting ell-shaped rod was rotated at 100 rpm for 2 minutes by means of the apparatus shown in FIG it was allowed to finish cooling in air around a cellular rod with a diameter of 28 ± 0.2 mm, an aspect ratio greater than 0.98, a specific gravity of 0.38, a cell diameter of less than 300 microns and a to maintain a smooth surface.

Example 7

ίο A composition of 100 parts of ABS resin (density 1.06 g / cm ³ ) and 1.0 part of azodicarbonamide was extruded into a cellular tube at 200 ° C using an extruder with a single screw and a diameter of 40 mm, and the article was allowed to run for 2 minutes at 200 rpm using the method shown in FIG. 19 rotate and then cool to a hollow rod with an outer diameter of 15.0 ± 0.1 mm, a mean inner diameter

ao of 8 mm, an aspect ratio greater than 0.99, a specific gravity of 0.55, a average cell diameter of about 200 microns and a smooth surface.

Example 8

A composition of 100 parts of polystyrene (density 1.07 g / cm ^s ), 2.5 parts of n-pentane, 0.2 part of citric acid and 0.2 part of sodium bicarbonate was made using a single screw extruder with a diameter of 65 mm was kneaded and extruded, and the obtained cellular rod was allowed to run for 3 minutes at 200 rpm using the method shown in FIG. 19 rotate to obtain a cellular rod having a diameter of 260.2 mm, an aspect ratio greater than 0.98, a specific gravity of 0.21, an average cell diameter of about 300 microns, and a smooth surface.

40

Claims (6)

Patent claims: 1. A method of making cellular rods from thermoplastic resin comprising essentially circular cross-section by extruding a kneaded mixture of the thermoplastic Resin and a foaming agent at elevated temperature and cooling the extruded Moldings, characterized in that the molding is produced while it is cooling can be rotated on a solid surface until its surface has solidified so far has that it no longer deforms under its own weight. 2. The method according to claim 1, characterized in that the direction of rotation of the Inverts the rod at least once. 3. Apparatus for performing the method according to claim 1 and 2, characterized by a system of at least two alternately inclined surfaces (2 ', 2 ", T") and devices (10) for deflecting the molding from one to the other other area. 4. Apparatus for performing the method according to claim 1, characterized by a rotating cylinder (13) forming a support surface for the briquettes, a ring in the substantially equally spaced apart from the cylinder surface Guide rollers (15), two supporting the guide rollers, arranged at both ends of the cylinder Disks (16) and drive devices, which the cylinder and the disks in different Drive direction. 5. Apparatus for performing the method according to claim 1, characterized by an endless conveyor belt (19) forming a support surface for the briquettes, essentially several equally spaced, in Distance from the conveyor belt surface angeord designated guide rollers (15), two the guide rollers supporting endless plates (20) and drive devices arranged on both sides of the conveyor belt, which drive the conveyor belt and the endless plates in different directions. 6. Apparatus for performing the method according to claim 1, characterized by a system of rotating rollers whose mutual distance is smaller than the diameter of the Moldings is, and drive devices that drive the rollers in the same direction of rotation. For this purpose 4 sheets of drawings