Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/34—Auxiliary operations
  • B29C44/36—Feeding the material to be shaped
  • B29C44/46—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length
  • B29C44/461—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length dispensing apparatus, e.g. dispensing foaming resin over the whole width of the moving surface

Definitions

• the invention relates to a method and an apparatus for producing polyurethane block foam.
• block foam e.g. polyurethane (PUR)
• the reactive components polyol and isocyanate and other additives such. Catalysts, stabilizers, blowing agents, dyes dosed in exact mixing ratios to each other, then conveyed to a mixer and mixed there.
• Stirrer mixers are commonly used, but static mixers can also be used.
• the reactive mixture is applied to the bottom paper of a circulating conveyor belt or, as shown in FIG. 1, applied to the base paper drawn over an application plate and conveyed further through the conveyor belt into the actual block foam installation, where it foams up and reacts out. Subsequently, the resulting foam is cut into blocks and transported to the warehouse, where it is vented and cooled before it is released for further assembly.
• the manner in which the reactive mixture is applied to the base paper guided over the conveyor belt or the application plate is of decisive importance for the quality of the subsequently resulting block foam.
• the smallest air bubbles which are swirled when applying the reactive mixture or mixed into suction zones, in the subsequent reaction and blowing process to Pinholes and voids and thus inferior goods.
• the momentum forces of the flow are directed in the middle in the transport direction and on the sides against the side walls. This additionally reinforces the effect of leading the medium flow and has the consequence that in each plane perpendicular to the transport direction different old mixture is present. This in turn has the negative effect that the older mixed in the marginal areas of the bottom paper, which reacts earlier and expands, lying next to moving younger mixture to the rear. These shifts in turn lead to streaks, to different densities, to different cell structures and ultimately to cracks and thus to rejects.
• DE-OS-39 05 914 a further discharge system is described.
• a mixing head is followed by a distributor nozzle, which is formed by two side walls defining a narrow gap which is open at the bottom and to the side (column 3, lines 29 to 31 and also Figures 1 and 2 of DE-OS 39 05 914).
• the invention relates to a process for the preparation of polyurethane block foam, in which the reactive components polyol and isocyanate are metered to a mixer, mixed therein and then discharged from the mixer and applied to the base paper, characterized in that the reactive mixture after leaving the flow rate of the mixture at the edge of the distributor substantially transversely to the transport direction flowing mixture components are higher than the flow rates of the mixture portions, which emanate in the transport direction forward edge of the distributor substantially in the transport direction of the mixer and arranged directly above the bottom paper wherein the reactive mixture leaves the distribution device in the form of a film which forms an interface with the ambient atmosphere only at the top.
• the base paper is usually the paper web or other suitable separating web, which rests on the conveyor belt and / or on the application plate and is guided over it.
• the bottom paper can thus ggt. also made of a material other than paper.
• the reactive mixture is conducted in such a way that it flows off immediately above the base paper (ie also directly above the conveyor belt or the application plate) in an atmosphere surrounding it. Distribution tongue) happens.
• the reactive mixture preferably flows parallel to the surface of the bottom paper (or the conveyor belt or the application plate).
• the distribution device causes the flow. speeds of the mixture components flowing out at the edge of the distributor substantially transversely to the transport direction are higher than the flow velocities of the identifyrous components flowing out in the transport direction in the central region of the distributor, preferably by a factor of 1.5 to 200, particularly preferably by a factor of 2.0 to 100, most preferably by a factor of 2.5 to 50. This causes, after leaving the distribution - A -
• tion sets a mixture distribution with a constant over the width of the bottom paper layer thickness and the reactive mixture moves in a parallel flow over the width of the bottom paper constant speed, the speed of the flow of the transport speed of the conveyor belt or, the bottom paper corresponds, that is also then there is no longer any relative speed between the base paper and the reactive mixture.
• the distributor is located immediately above the bottom paper, i. H. preferably at a distance of up to 50 mm, more preferably less than 10 mm.
• block foam can be produced in this way without streaking, without cell disruption, without density differences and without cracks.
• the reactive mixture leaves the distribution device in the form of a film, which forms an interface with the ambient atmosphere on only one side at the top.
• the invention also relates to a device for the production of polyurethane block foam umfalsend.
• the device according to the invention is preferably used in the method according to the invention.
• the gap through which the reactive mixture flows before exiting the distributor device is oriented essentially parallel to the base paper.
• the mixing zone or the mixture outlet channel is followed by a distributor device which can have approximately the contour of a tongue and which defines a gap.
• the reactive mixture must pass before flowing out into the atmosphere, which is arranged directly above the conveyor belt or the order plate.
• the gap which the reactive mixture has to pass before flowing out into the atmospheric environment runs substantially parallel to the base paper, ie also substantially parallel to the conveyor belt or to an application plate.
• the cross section of the gap may be designed so that the upper and the lower part of the distributor are parallel to each other or forward, ie, seen in the transport direction, tapered, arranged. Contoured surfaces, in particular on the inside of the upper part of the distributor, are also possible.
• the distributor may also be designed so that the underside of the distributor, i. the bottom paper-facing side of the distributor, in the transport direction and possibly also transversely to the transport direction is further expanded than the top of the distributor.
• the reactive mixture then flows due to the different expansion of the bottom and top of the distribution device from an inclined towards the vertical outlet opening from the distributor.
• the ratio of the width b of the distributor to the width B of the produced PUR foam block is preferably 0.001 to 0.8, particularly preferably 0.005 to 0.3, very particularly preferably from 0.01 to 0, 1.
• the ratio of the length 1 of the distributor (in the transport direction) to the width b of the distributor (transverse to the transport direction) is preferably 0.5 to 20, more preferably 0.8 to 10, most preferably 1 to 5.
• the distributor consists of a lower and an upper part, wherein the lower part comprises a sheet which is inclined relative to the bottom paper and which forms at the transition to the base paper with this a straight transition edge.
• the liquid film leaving the distribution gap then first flows on the sheet before it flows over this edge onto the base paper.
• a flexible sealing lip or an overlapping foil is preferably attached.
• the distribution device consists of a lower and an upper part, wherein the lower part is formed by the conveyor belt and / or the application plate itself and the overlying base paper. It is important that a sealing element (eg in the form of a sealing lip) is arranged in the rear region of the distributor between distributor and conveyor belt and / or the application plate or the overlying base paper.
• a sealing element eg in the form of a sealing lip
• the upper distribution tongue has a bend precisely at the transition edge of the lower plate to the base paper, so that the lower part of the distribution device partly through the sheet and partly through the conveyor belt and / or the application plate and the overlying base paper itself is formed. This prevents, on the one hand, that too much pressure can act on the paper and, on the other hand, prevents the sheet from becoming too wide.
• the distance h between the upper edge of the distributor and the lower edge of the distributor is adjustable.
• the contour of the gap is adjustable in several places, so that even with different foaming widths, amounts and viscosities the best possible mixture distribution can be achieved without having to change the distribution device.
• the contour of the gap is adjustable in several places, so that even with different foaming widths, amounts and viscosities the best possible mixture distribution can be achieved without having to change the distribution device.
• the upper part of the distribution device is preferably adaptable to the circumstances by the adjustability of the gap.
• the symmetry axis of the mixing zone in the mixer or the mixture outlet channel forms with the plane of the gap of the distributor preferably an angle of 5 ° to 175 °, more preferably from 45 ° to 135 °, most preferably from 80 ° to 100 °.
• this angle is also adjustable.
• Fig. 1 is a schematic representation of a block foam plant according to the prior art.
• Fig. 2 shows a device according to the invention in section OC
• FIG. 3 the same device as in Figure 2 in section B- ⁇ B.
• Fig. 4 shows a variant of the device according to the invention, wherein the lower part of the distributor device is formed by the application plate itself.
• FIGS. 5 to 9 show variants of distribution device.
• FIG. 1 shows a plant for the production of PUR block foam according to the prior art.
• the reactive components polyol and isocyanate and the additives are conveyed in exact mixing ratios by means of metering pumps (not shown) continuously to a mixer 1, mixed therein and an outlet channel 2 on the bottom paper 3, which is pulled by the conveyor belt 4 on the application plate 5, applied, and then further conveyed by the conveyor belt 4 in the actual block foam plant, where it foams and reacted.
• the arrow 16 indicates the transport direction of the conveyor belt. Subsequently, the resulting foam is cut into blocks by means of a sawing device 15 and transported to a warehouse.
• Figure 2 shows a device according to the invention in section OC (the position of the section OC is shown in Figure 3).
• the reactive components polyol and isocyanate and the additives are continuously conveyed in exact mixing ratios in the mixer 1 and mixed therein.
• the reactive mixture leaves the mixer 1 via the mixture outlet channel 2.
• the finished reactive mixture is then guided so that it flows off directly above the application plate 5 parallel to the application plate.
• a filler piece 9 is arranged in the inlet of the distributor head.
• Figure 3 shows the device according to the invention shown in Figure 2, but in section B ⁇ B.
• Essential in this figure is the representation of the streamlines 10 of the effluent reactive mixture.
• FIG. 4 shows a variant of the device according to the invention, in which the Verteü listening 8 consists of an upper and a lower part, wherein the lower part of the distributor 8 is formed by the application plate 5 itself and the base paper 3 arranged above.
• a sealing element 12 is arranged in the rear region of the distributor device 8 between the distributor device 8 and the application plate 5.
• the symmetry axis 13 of the mixer 1 and the mixture outlet channel 2 and the plane 14 of the distributor 8 form the angle ⁇ with each other.
• This angle can also be adjustable (not shown in detail) to adapt the system to changing order plate inclinations.
• Figures 5, 6, 7, 8 and 9 show embodiments of various distribution device 8, wherein not only the shape, but also the ratios 1 / b and b / B can be variable.
• the new method and the new device can be used variably. In fact, it is irrelevant whether the base paper, to which the reactive mixture is applied, is drawn away under the mixing head or the discharge element in a predetermined transport direction, or whether in so-called stationary block foam plants the mixing head or the discharge element moves over the fixed base paper ,

Landscapes

• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Polyurethanes Or Polyureas (AREA)
• Paper (AREA)
• Coating Apparatus (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (10)

Cited By (1)

Families Citing this family (10)

Citations (2)

Family Cites Families (5)

• 2005
  • 2005-02-04 DE DE102005005151A patent/DE102005005151A1/de not_active Withdrawn
• 2006
  • 2006-02-01 DE DE502006000881T patent/DE502006000881D1/de not_active Expired - Lifetime
  • 2006-02-01 RU RU2007132961/04A patent/RU2007132961A/ru not_active Application Discontinuation
  • 2006-02-01 CN CNA2006800038591A patent/CN101111356A/zh active Pending
  • 2006-02-01 SI SI200630071T patent/SI1846212T1/sl unknown
  • 2006-02-01 WO PCT/EP2006/000866 patent/WO2006082036A1/de not_active Ceased
  • 2006-02-01 JP JP2007553529A patent/JP5069566B2/ja not_active Expired - Lifetime
  • 2006-02-01 EP EP06706546A patent/EP1846212B1/de not_active Expired - Lifetime
  • 2006-02-01 US US11/883,310 patent/US20080145544A1/en not_active Abandoned
  • 2006-02-01 PL PL06706546T patent/PL1846212T3/pl unknown
• 2007
  • 2007-08-31 NO NO20074456A patent/NO20074456L/no not_active Application Discontinuation

Patent Citations (2)

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