IES930547A2 - A process for producing a substantially flat-topped¹polyurethane foam block - Google Patents
A process for producing a substantially flat-topped¹polyurethane foam blockInfo
- Publication number
- IES930547A2 IES930547A2 IES930547A IES930547A2 IE S930547 A2 IES930547 A2 IE S930547A2 IE S930547 A IES930547 A IE S930547A IE S930547 A2 IES930547 A2 IE S930547A2
- Authority
- IE
- Ireland
- Prior art keywords
- mass
- conveyor
- substantially flat
- topped
- arrangement
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 21
- 239000006260 foam Substances 0.000 title description 5
- 239000000463 material Substances 0.000 claims abstract description 26
- 229920002635 polyurethane Polymers 0.000 claims abstract description 16
- 239000004814 polyurethane Substances 0.000 claims abstract description 16
- 230000000630 rising effect Effects 0.000 claims abstract description 16
- 229920005830 Polyurethane Foam Polymers 0.000 claims abstract description 12
- 239000011496 polyurethane foam Substances 0.000 claims abstract description 12
- 239000000376 reactant Substances 0.000 claims abstract description 6
- 239000000126 substance Substances 0.000 abstract description 3
- 239000006261 foam material Substances 0.000 abstract description 2
- 238000002156 mixing Methods 0.000 description 4
- 239000002699 waste material Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 235000008429 bread Nutrition 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000012985 polymerization agent Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000003340 retarding agent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Landscapes
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
A process is described for producing substantially flat-topped polyurethane foam blocks or slabstock. The required chemical reactants are delivered to a conveyor trough arrangement which advances a mass of rising foamed polyurethane material away from the delivery station. An arrangement of overhead fans directs pressure air to the central or highest potion of the rising mass of foam material and may be controlled and contained by adjustable baffle panels to produce a substantially flat-topped polyurethane foam block and also accelerate the subsequent curing step before the block can be cut into smaller pieces.
Description
The present invention relates to a process for producing foamed polyurethane blocks as slabstock material, and in particular relates to a process for producing a flat-topped block which reduces waste and improves subsequent handling of the block.
Hitherto, chemical reactants including urethane monomer and a polymerization agent and foaming/retarding agents are metered separately and pumped to a mixing head where they are blended. The mixed reactants are delivered from the blending chamber directly to a moving trough conveyor. As the blended mixture is carried slowly forwards by the belt, the polymerization reaction continues and the resultant foamed polyurethane rises and sets to form a polyurethane foam block which may have a hight and width of 1-2 metres. At the end of the conveyor, which may be over 50 metres in length, when the block is sufficiently stable to handle, it is cut into slabs which undergo a subsequent curing step in a storage area before being used for subsequent processing or cut into smaller shapes.
Polyurethane foam blocks produced in this manner naturally assume a rounded upper surface since the sides of the conveyor trough apply a certain drag to the rising material, similiar to the way in which a rising loaf of bread assumes a rounded top. This rounded profile gives rise to significant waste when the block is subsequently squared by cutting machines to produce sheets, for example. Also, the rounded upper surface of the slabstock causes difficulty in handling and stacking the slabstock.
- 2 ►930 54 7
Several techniques are known for improving the flattening of the upper surface of the foam block as it rises and sets. These include an arrangement of film material or paper arranged to move upwardly over the sides of the conveyor trough arrangement and at an angle, so as to pull the sides of the rising foam block upwards at a faster rate than would otherwise occur because of frictional drag referred to above. However, this is a difficult process to operate in a long conveyor line and results in wastage of large quantities of film or paper material. Alternatively, film material or paper is laid continuously on top of the rising foam block, and boards, slides, paddles or other devices are used to apply pressure to force the highest part of the rising foam mass towards the sides. However, this process is difficult to control and may not result in a completely flat topped block since further gentle rising may occur during the curing stage.
An object of the present invention is to provide an improved process to produce uniformally shaped and flat-topped blocks of polyurethane foam material. Another object is to achieve a reduction in costs over known processes. Yet another object is to accelerate the curing stage of the process.
According to the present invention, there is provided a process for producing substantially flat-topped polyurethane foam blocks, comprising the steps of
- delivering blended reactants required to produce a foamed mass of polyurethane material to a conveyor trough arrangement,
- advancing the mass of foamed polyurethane material forwardly along the conveyor trough away from the delivery station,
- applying downwards air pressure to the top of the mass of foamed polyurethane material from above the conveyor trough arrangement, at spaced intervals along the conveyor,
- removing a block from the mass of foamed polyurethane material at the end of the conveyor when sufficient time has lapsed for the material to stabilize and cool.
- 3 MJ0 54 7
Preferably, the downwards air pressure is provided by an arrangement of overhead fans.
Advantageously, baffle means are arranged to each side of the fans so as to contain the downward air pressure and direct it towards the central or highest portion of the rising mass of foamed polyurethane material. Preferably, the baffle means comprises laterally adjustable baffle panels allowing the area over which downward air pressure is to be applied to be altered.
Preferably, the air directed towards the top of the rising mass of foamed polyurethane material is extracted by a tunnel extraction system or is recirculated for subsequent extraction.
A preferred embodiment of a process for producing substantially flat-topped polyurethane foam blocks will now be described with reference to the accompanying drawings, in which
Figure 1 is a schematic side elevation of the production line, and Figure 2 is a schematic cross-section through the conveyor arrangement.
Referring to the drawings, the chemical reactants necessary for producing foamed polyurethane material are metered separately and pumped to a mixing head where they are blended in a blending chamber in a known manner prior to delivery from delivery station 1 to a moving conveyor trough arrangement 2. The conveyor trough arrangement comprises a base conveyor 3 and side conveyors 4, 5, which advance the mass of rising and reacting foamed polyurethane material away from the delivery station. Normally, the conveyors are lined with a film of non-stick film material or paper. The side conveyors 3, 4 may be stationary side walls lined with a moving sheet of film material.
*»930 54 7
- 4 An arrangement of overhead fans, 6, spaced at intervals along the conveyor trough arrangement directs a strong downward current of air to apply pressure to the top of the rising mass of polyurethane foam material. The fans are arranged with side baffle panels, 7, 8 so as to contain the downward air thrust to the central or highest portion of the rising foam material. The baffle panels 7, 8 may be moved laterally towards the sides of the conveyor trough so as to apply a downward thrust to a wider area of the continously rising block of polyurethane foam material. However, no pressure air is applied to the outer extremities of the block which tend not to rise as fast as the central portion. Thus, the force applied may be adjusted by changing the fan speed, and the area over which the force is applied may be adjusted by moving the baffle panels, such that the process may be controlled to produce a flat-topped polyurethane foam block 11 by the time the block is cut from the end 9 of the conveyor arrangement, at a cutting station 10.
The process is less wasteful than prior art processes as a substantially flat-topped slabstock may be produced which does not have to be cut to size. Another advantage of the process is that the top portion of the rising slabstock is cooled more quickly than heretofore, forming in effect a stable flat-topped crust which reduces the time taken for the blocks removed from the conveyor to cure. The crust may also resist any tendency for the top of the block to swell further during curing. Normally, the blocks which are cut from the end of the conveyor in a continuous process have to be allowed to stand for a considerable time to effect complete cooling and curing before the block can be cut into smaller pieces. Furthermore, the substantially flat top of the resultant slabstock allows for easier handling, wherein the blocks can be stacked, and time is saved by not having to cut any rounded top portion from the slabstock which of course results in waste, which cannot always be recycled.
Claims (5)
1. A process for producing substantially flat-topped polyurethane foam blocks, comprising the steps of - delivering blended reactants required to produce a foamed mass of polyurethane material to a conveyor trough arrangement, - advancing the mass of foamed polyurethane material forwardly along the conveyor trough away from the delivery station, - applying downwards air pressure to the top of the mass of foamed polyurethane material from above the conveyor trough arrangement, at spaced intervals along the conveyor, - removing a block from the mass of foamed polyurethane material at the end of the conveyor when sufficient time has lapsed for the material to stabilize and cool.
2. A process according to claim 1, in which the downwards air pressure is provided by an arrangement of overhead fans.
3. A process according to claim 2, in which baffle means are arranged to each side of the fans so as to contain the downward air pressure and direct it towards the central or highest portion of the rising mass of foamed polyurethane material.
4. A process according to claim 3, in which the baffle means comprises laterally adjustable baffle panels allowing the area over which downward air pressure is to be applied to be altered.
5. A process for producing substantially flat-topped polyurethane foam blocks, subsantially as described herein, with reference to, and as shown in, the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IES930547 IES59599B2 (en) | 1993-07-20 | 1993-07-20 | A process for producing a sutstantially flat-topped polyurethane foam block |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IES930547 IES59599B2 (en) | 1993-07-20 | 1993-07-20 | A process for producing a sutstantially flat-topped polyurethane foam block |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IES930547A2 true IES930547A2 (en) | 1994-03-09 |
| IES59599B2 IES59599B2 (en) | 1994-03-09 |
Family
ID=11040024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IES930547 IES59599B2 (en) | 1993-07-20 | 1993-07-20 | A process for producing a sutstantially flat-topped polyurethane foam block |
Country Status (1)
| Country | Link |
|---|---|
| IE (1) | IES59599B2 (en) |
-
1993
- 1993-07-20 IE IES930547 patent/IES59599B2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| IES59599B2 (en) | 1994-03-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK9A | Patent expired |