WO1994008774A1

WO1994008774A1 - Process and spray head for producing and/or coating extruded sections

Info

Publication number: WO1994008774A1
Application number: PCT/EP1993/002816
Authority: WO
Inventors: Burkhard Metzger; Hans Joachim Ziolkowski
Original assignee: Krupp Bellaform Maschinenbau Gmbh
Priority date: 1992-10-17
Filing date: 1993-10-13
Publication date: 1994-04-28
Also published as: JPH07504861A; DE4235101C2; DE4235101A1

Abstract

To form coloured-structure extruded sections and/or coating thereof, use is made of an at least two-coloured plastic material which is divided into at least two partial flows which are brought together again before leaving the extrusion head (1) while largely retaining their partial flow form. These partial flows may again be divided into further partial flows. The extrusion head (1) has a distributor plate (4) in which there are distribution channels (8a, b) in the form of grooves and also an annular channel (11) which is connected to the outlet channel (38) via an annular slot (19, 20). The plasticised material entering the outlet channel (38) via the annular slot (19, 20) surrounds the prefinished extruded section (39) introduced through the guide component (13) and the extrusion nozzle (24).

Description

Process and spray head for producing and / or covering extruded profiles

Description:

The invention relates to a method for the continuous production and / or sheathing of extruded profiles, wherein a plasticized material is fed to an extrusion die head and is pressed through it. The invention also relates to a spray head for producing and / or enveloping extruded profiles with a feed channel for feeding plasticized material from a plasticizing and conveying device and with an outlet channel connected to the feed channel.

In the case of polymer pencils, in particular those whose lead coating consists of materials mixed with polymers, it is desirable to imitate the wood grain of conventional pencils using a suitable color structure. With the previous production methods, it was only possible to produce color-homogeneous lead coatings or color structures that are not comparable to wood grain.

From DE-OS 20 30 578 a spray head is known in which the extrusion nozzle is surrounded by an annular channel which is connected on the one hand to the plasticizing device via a feed channel and on the other hand ends in an annular slot which points counter to the direction of ejection of the extrusion nozzle and which runs around a deflection edge leads at the inlet end of the extrusion die and opens into the nozzle channel. With this known spray head, extruded profiles can be produced or encased. Structuring the extruded profiles or however, the jacket cannot be created with this spray head.

From DE-GM 19 27 405 a deflection spray head is known, which is mainly used for the production of hoses and tubular films, but also for cable sheathing. The aim here is to ensure that the pressure, temperature, viscosity and speed values are distributed evenly over the entire circumference of the ring nozzle. Two partial flows are combined in the deflection spray head, which are then combined with the partial flows thus formed in the outlet channel. Due to the acute-angled arrangement of the channels for the partial flows, that is to say the design of the flow islands, the partial flows cross, which leads to an intensive mixing of these partial flows. This is supported by the fact that the space behind the point of union of the partial streams widens in the exit direction. A deflection spray head of this type is not suitable for generating a pattern, since the partial flows are completely mixed.

From DE-OS 19 63 161 a method for the production of objects with wood grain-like properties from thermoplastic materials is known. With regard to the structuring, it is crucial that the pigment content of the color granules is considerably greater than that of the basic mixture.

The object of the invention is a method and a spray head for the production and / or sheathing of extruded profiles, the extruded profile and / or the Sheathing should have a colored structure that resembles in particular a wood grain.

This object is achieved with a method according to claim 1. The spray head according to the invention is the subject of claim 6.

An at least two-tone plasticized material is used as the material for producing the extruded profile and / or the casing. A two- or multi-colored material can be produced, for example, by adding several dyes to the plasticized material and by not carrying out homogeneous mixing. After the production of the at least two-tone, plasticized material, it is divided into at least two partial flows and then these partial flows are brought together again before the exit from the spray head while largely maintaining the partial flows. In this way, extruded profiles and / or sheathing of extruded profiles can be produced which, for example in the case of a conical cut, such as when sharpening pencils, have arc-shaped colored structures which are comparable to a wood grain. It has been found here that there is a correlation between the number of the arched structure and the number of partial flows, so that the structure of the imitated wood grain can be adjusted via the number of partial flows.

In order to achieve a structuring that is as fine as possible, the respective partial streams can in turn be divided into further partial streams, which are brought together again while largely maintaining these partial streams before they exit the spray head. When merging the partial streams, care must be taken that a complete mixing of the partial streams is avoided because otherwise the arcuate structures mentioned can no longer occur in the desired manner.

In order to achieve a largely symmetrical structuring, it is advantageous if the plasticized material is divided into partial streams of equal size.

According to a special embodiment, the partial flows are brought together in a direction perpendicular to the exit direction of the spray head and then deflected together in the exit direction. The space in which the partial flows are initially brought together is preferably an annular space.

To carry out this method, a specially equipped spray head is required, which has at least one feed channel through which plasticized material from a plasticizing and conveying device, for. B. is fed to an extruder. According to the invention, at least two distributor channels are provided between the feed channel and the outlet channel of the spray head, which open out at spaced locations into a collecting channel, which is preferably an annular channel, which in turn is connected to the outlet channel via an annular slot. The number of distribution channels, the distribution channels also being able to open into sub-distribution channels, depends on the type of color structuring of the extruded profile and / or the sheathing of the extruded profile desired. This means that each sub-distribution channel can be divided into at least two further sub-distribution channels can be divided so that an arbitrarily fine structuring can be achieved.

In order to achieve the shortest possible length of the spray head, it has proven to be advantageous if the distributor channels open into the ring channel in the radial direction, the ring channel preferably being arranged perpendicular to the longitudinal axis of the outlet channel. In order to achieve regular structuring along the circumference of the extruded profile and / or the sheathing, it is advantageous to have the distributor channels open into the ring channel at equidistant locations.

The distribution channels preferably each have the same cross-section.

Depending on whether an extruded profile or a sheathing of a prefabricated extruded profile or a multiple sheathing is to be created, the position of the ring channel in the spray head must be appropriately provided. If an already prefabricated extruded profile is inserted into the spray head, the ring channel is arranged in such a way that it surrounds the prefabricated extruded profile. In this case, the ring channel is preferably arranged in the exit direction in front of the nozzle of the spray head with which the ring channel is connected. If, for example, two sheaths are to be applied simultaneously to an extruded profile, the ring channel for the outer sheath can be arranged in the spray head behind the nozzle in the pull-off direction.

If an extruded profile is to be produced or a prefabricated extruded profile is merely to be provided with a covering which has the desired color structure, then one is Distribution plate required, which has the distribution channels around the ring channel. The distributor channels and the annular channel are preferably formed as grooves in the distributor plate, which are covered by a cover plate resting on the distributor plate, leaving an annular opening in the region of the annular channel. Through this ring opening, the merged partial streams can either exit directly into the outlet channel, this ring opening being designed as an annular slot, or the partial streams are fed through a ring slot extending in the axial direction to a nozzle part in which there is a nozzle mandrel. The cover plate can thus either form the end plate of the spray head and have a central bore for the outlet channel, or the cover plate is designed as an intermediate plate between the distributor plate and a nozzle part. In the latter case, the cover plate preferably also has the feed channel which opens into the distributor channels.

The cover plate preferably has a central bore which, together with an insert projecting into the bore, delimits at least a first section of the ring slot. The insert can be a tubular extension of the distributor plate, which in turn receives a guide insert with a bore tapering in the exit direction for inserting a prefabricated extruded profile. A nozzle part adjoins this cover plate in the exit direction and, together with a nozzle mandrel arranged in the nozzle part, delimits a second section of the ring slot. If a prefabricated extruded profile is to be encased, this nozzle mandrel has a central hole that matches the hole in the guide insert flees. The prefabricated extruded profile is inserted through this hole into the outlet channel of the spray head, where the desired sheathing takes place.

If it is not a sheathing but the formation of the extruded profile in the spray head that is to be produced, the nozzle mandrel just described can be replaced by a nozzle mandrel without a central bore.

In the event that the extruded profile and / or the sheathing of the extruded profile with a further sheathing z. B. to be provided with a thin outer layer, which should also have such a colored structure, according to a further embodiment the nozzle part can also be provided on its end face with distributor channels and an annular channel, which are introduced as grooves in the nozzle part. These grooves are then covered by the end plate of the spray head, which has a central bore for forming the outlet channel. Preferably, this nozzle part also has the feed channel, which is connected on the one hand to the distribution channels and on the other hand with a plasticizing and conveying device, such as. B. is connected to an extruder. These distribution channels can also be branched into further sub-distribution channels. The cover plate is designed in such a way that an annular slot remains free between the inner edge of the ring channel and the end plate, through which the plasticized, at least two-tone material can exit into the outlet channel.

Characterized in that the distribution channels and the ring channels are made as grooves in the respective components of the spray head, which is advantageous from the manufacturing point of view, these channels have a semicircular cross section. The distribution channels are preferably designed so that they are of equal length. This results in an even distribution of the structuring over the entire circumference.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Show it:

FIG. 1 shows a longitudinal section through the spray head,

FIG. 2 shows the top view of the distributor plate,

FIG. 3 shows the top view of the nozzle part,

4 shows a longitudinal section through the spray head according to a further embodiment and

Figure 5 shows a pointed pen in perspective.

In Figure 1, the spray head is shown in longitudinal section. This spray head 1 has a distributor plate 4, which counter to the

Exit direction of the spray head 1, which is indicated by the arrow, is delimited by an end plate 2 and in the exit direction by a cover plate 16. The end plate 2 has a central bore 3, so that at least one prefabricated extruded profile 39 can be inserted into the spray head 1. The distributor plate 4 also has a central bore 5 which continues in the tubular extension 6 of the distributor plate 4, in which a guide insert 13 is arranged. This guide insert, which is fastened to the distributor plate 4 with its fastening flange 15, has a bore 14 tapering in the exit direction so that the prefabricated extruded profile 39 can enter the spray head 1 without damage.

The distribution channels 8a, 8b and sub-distribution channels 9a, 9b, 10a, 10b (see FIG. 2) and the annular channel 11 are formed in the form of grooves in the outlet-side end face of the distributor plate 4. These grooves are covered by the cover plate 16, which also has the feed channel 17, which opens into the distributor channels 8a, 8b, an annular opening 44 being left free in the area of the annular channel 11, through which the partial flows brought together in the annular channel 11 into the through the Outer surface 7 of the tubular extension 6 and the central bore 18 of the cover plate 16 limited ring slot 19 can emerge. The first section 19 of the ring slot opens into the second section of the ring slot 20, which is formed by the nozzle part 22 and the mandrel 24, which abuts the end face 12 of the tubular extension 6. The nozzle part 22 has a conical inner surface 23 to which the configuration of the nozzle mandrel 24 is adapted. The nozzle mandrel 24 has a central bore 25 which is aligned with the tapered bore 14 of the guide insert 13. The nozzle mandrel 34 has a cylindrical spinous extension 26 which projects into the outlet channel 38. The outlet channel 38 is formed by a corresponding bore in the nozzle part 22 and the central bore 37 of the end plate 36.

The nozzle part 22, which is fastened to the cover plate 16 by means of the holding plate 27 and is adjustable and fixable in the radial direction by means of adjusting screws 28, likewise has distribution channels 32a, b and sub-distribution channels 33a, b, 34a, b and one on its end face 30 Annular channel 35 in the form of grooves. The distributor channels 32a, b are connected to the feed channel 31 in the nozzle part 22, which is connected to a further plasticizing and conveying device (not shown). The end plate 36 is designed such that the distributor and sub-distributor channels 32a, b, 33a, b, 34a, b and the ring channel 35 are covered, an annular opening 44 in the form of an annular slot 46 remaining free in the region of the annular channel 35, so that the conveyed plasticized material from the annular channel 35 can enter the outlet channel 38 and covers the casing formed by the nozzle part 22. The spray head 1 is surrounded by heating tapes 21 and 29 in order to keep the plasticized material at the temperature required for the extrusion.

FIG. 2 shows the top view of the distributor plate 4. The feed channel 17 opens into the branching point 45 of the distributor channels 8a and 8b. The plasticized material fed through the feed channel is thus divided by deflection by 90 ° into two partial streams which flow along the distribution channels 8a and 8b to the ring channel 11. In the embodiment shown here, the two distribution channels 8a and 8b are arranged such that they extend outward from the branching point 45 in the opposite direction. The distribution channels 8a and 8b have at their end an arcuate section 8 "which leads radially to the annular channel 11. This arcuate section 8 'branches into two sub-distribution channels 9a and 9b or 10a and 10b. The cross section of these sub-distribution channels 9a, 9b, 10a, 10b is smaller than the cross section of the distribution channels 8a and 8b. These sub-distribution channels also each have a curved section 9 ', 10' at their end, which radially opens into the annular channel 11. The sub-distribution channels have the same cross-section and the same length. The entry points of the sub-distribution channels 9a, 9b, 10a, 10b into the ring channel 11 are distributed equidistantly along the circumference of the ring channel 11, so that in each case 2 sub-distribution channels 9a, 10b or 9b and 10a lie opposite one another.

FIG. 3 shows the view of the end face of the nozzle part 22. The feed channel 31 opens into the two distribution channels 32a and 32b, which branch into sub-distribution channels 33a, 33b or 34a and 34b. These sub-distribution channels open into the ring channel 35. The configuration of the distribution channels 32a, 32b and the sub-distribution channels 34a, 34b and 33a, 33b corresponds to the configuration of the distribution and sub-distribution channels in FIG. 2, so that reference can be made to these explanations.

4 shows a further embodiment of the spray head 1 in longitudinal section. This spray head is designed for the production of extruded profiles, which are covered with a thin outer layer. The difference from the embodiment of FIG. 1 is that the nozzle mandrel 24 has been replaced by a closed nozzle mandrel 24a.

FIG. 5 shows a tipped encased extruded profile 40 in a perspective view. This coated extruded profile 40 can be a pen, for example. In this case, the prefabricated extruded profile 39 represents the writing lead and the casing 41 represents the lead casing. A further outer layer 42 is applied to the mine casing 41. If for the sheath 41 a plasticized two-tone Material is introduced through the feed channel 17 of the embodiment of the spray head 1 shown in FIG. 1, the casing 41 shows, after sharpening, arc-shaped color structures 43 which resemble a wood grain of a pencil. The number of arcuate structures 43 is correlated with the number of partial flows and thus with the number of distribution channels or sub-distribution channels. Depending on the type of material used and the degree of mixing of the partial flows, these arcuate structures 43 appear more or less clearly. If the partial flows are mixed slightly on the way to the outlet opening of the spray head 1, the number of arcuate structures 43 corresponds to the number of partial flows.

Reference symbol list:

Claims

1. A process for the continuous production and / or sheathing of extruded profiles, a plasticized material being fed to a spray head and being pressed through it, characterized in that

that an at least two-tone, plasticized material is used, which is divided into at least two sub-streams, and

that these partial flows are merged again before leaving the spray head while largely maintaining the partial flows.

2. The method according to claim 1, characterized in that at least one substream is divided into at least two further substreams.

3. The method according to claim 1 or 2, characterized in that the respective partial flows are the same size.

4. The method according to any one of claims 1 to 3, characterized in that the partial flows are brought together in a direction perpendicular to the exit direction and then deflected together in the exit direction.

5. The method according to any one of claims 1 to 4, characterized in that the partial flows are brought together in an annular space.

6. Spray head for producing and / or enveloping extruded profiles with a feed channel for feeding plasticized material from a plasticizing and conveying device and with an outlet channel connected to the feed channel, characterized in that

that the feed channel (17, 31) is connected to at least two distributor channels (8a, b, 32a, b) which open out at spaced locations in an annular channel (11, 35) which is connected to the via an annular slot (19, 20) Exit channel 38 is connected.

7. Spray head according to claim 6, characterized in that at least two supply channels (17, 31) are provided which are each connected to their own distribution channels (8a, 8b, 32a, 32b).

8. Spray head according to claim 6 or 7, characterized in that at least one distribution channel (8a, b, 32a, b) opens into at least two sub-distribution channels (9a, b, 10a, b, 33a, b, 34a, b) the ring channel (11, 35) are connected.

9. Spray head according to one of claims 6 to 8, characterized in that the collecting channel is an annular channel (11, 35).

10. Spray head according to claim 9, characterized in that the distributor channels (8a, b, 32a, b) open out in the radial direction at equidistant points in the annular channel (11, 35).

11. Spray head according to one of claims 6 to 9, characterized in that the distributor and sub-distributor channels (8a, b, 32a, b, 9a, b, 10a, b, 33a, b, 34a, b) each have the same cross section.

12. Spray head according to one of claims 6 to 11, characterized in that the annular channel (11, 35) is arranged perpendicular to the longitudinal axis of the outlet channel (38).

13. Spray head according to one of claims 6 to 12, characterized in that the annular channel (35) surrounds the outlet channel (38).

14. Spray head according to one of claims 6 to 13, characterized in that the distributor channels (8a, b, 32a, b) and the annular channel (11, 35) are designed as grooves in a distributor plate (4) which are formed by a cover plate ( 16) are covered leaving a ring opening (44) in the area of the ring channel (11, 35).

15. Spray head according to claim 14, characterized in that the cover plate forms the end plate (36) of the spray head (1) and has a central bore (37) for the outlet channel (38).

16. Spray head according to claim 14, characterized in that the cover plate (16) has the feed channel (17).

17. Spray head according to claim 14 or 16, characterized in that the cover plate (16) has a central bore (18) which together with an insert protruding into the bore (18) delimits at least a first section (19) of the ring slot.

18 spray head according to claim 17, characterized in that the insert is a tubular extension (6) of the distributor plate (4) which receives a guide insert (13) with a tapering bore in the exit direction (14) for inserting a prefabricated extruded profile (39) .

19. Spray head according to one of claims 6 to 18, characterized in that a nozzle part (22) adjoins the cover plate (16) in the exit direction and, together with a nozzle mandrel (24, 24a) arranged in the nozzle part (22), a second section ( 20) of the ring slot limited.

20. Spray head according to claim 19, characterized in that the nozzle mandrel (24) has a central bore (25) which is aligned with the bore (14) of the guide insert (13).

21. Spray head according to one of claims 19 or 20, characterized in that the end face (30) of the nozzle part (22) pointing in the exit direction has the distributor channels (32a, b) and the annular channel (35), the distributor channels (32a, b ) with a second feed channel (31) and the ring channel (35) via an ring slot (46) with the outlet channel (38).

22. Spray head according to one of claims 6 to 21, characterized in that the distribution channels (8a, b, 32a, b) and the sub-distribution channels (9a, b, 10a, b, 33a, b, 34a, b) and the annular channel ( 11, 35) have a semicircular cross section.

23. Spray head according to one of claims 6 to 22, characterized in that the respective corresponding distribution channels (8a, b, 32a, b) and / or the sub-distribution channels (9a, b, 10a, b, 33a, b, 34a, b ) are the same length.