NL7908419A - METHOD AND APPARATUS FOR CONTINUOUS PRODUCTION OF POLYURETHANE FOAM. - Google Patents

Description

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Method and apparatus for the continuous production of polyurethane foam.

The invention relates to the continuous production of molded polyurethane foams, such as rigid, semi-rigid and flexible polyurethane foams.

Polyurethane foams are widely used as 5 materials from which products such as mattresses, chair cushion and thermal insulations are made. Such polymeric foam materials are usually made by a casting process in which a mixture of liquid polyurethane and foam-generating reagents is deposited in a mold. In the present application, the term "mold" includes both stationary molds for batch casting and rectilinear or otherwise moving molds for continuous casting. Evolution of a gas causes the reagents to foam. For some foam formulations, the reagents themselves react to generate sufficient gas; in others, a blowing agent is mixed with the reagents to provide gas evolution. Continued gas evolution causes the foam to expand until the mold is filled. The foam, initially a partially expanded liquid mixture, becomes increasingly viscous as the reagents polymerize and eventually cures into a polyurethane foam mold in the form of the surrounding form.

Polyurethane foam sheets that are approximately rectangular or circular in cross-section are usually cast in a rectilinearly channel-shaped form. Such molds usually include a conveyor forming the bottom of the mold and a pair of spaced opposing side walls which may be fixed or movable at the speed of the conveyor. The sides and bottom of the mold

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2 are generally lined with one or more sheets of flexible material, such as kraft paper or polyethylene film. The molding sheets are usually taken from rolls and moved continuously along the molding channel at the same speed as the conveyor belt. Liquid-5 foam-generating reagents are deposited on the bottom of the mold in a zig-zag pattern from a pour hole placed above the mold and reciprocated across the width of the mold. Typically, the reagents expand after flowing together to form an even slab of foam. Conventional production of foam products with rectangular and circular cross sections is described in U.S. Pat. Nos. 3,325,823, respectively. 3,325,573.

If fresh reagent mixture is deposited on foam formed from previously deposited reagents, the resulting cured foam will have an uneven surface and uneven density, which is undesirable for most applications. By continuous rectilinear movement of the molding, the reagent mixture is continuously carried away from the casting area below the pouring opening, which reduces the tendency of fresh reagent mixture to cover previously deposited reagent mixture.

Correct selection of the conveyor belt speed can prevent the production of unwanted foam products.

A range of rates can be established for a specific reagent mixture composition. The minimum speed is reached when liquid reagent mixture is evenly distributed on the bottom of the mold and does not flow in a direction opposite to that of the mold and the conveyor. Maximum speed is reached when the deposited liquid mixture starts to flow in the same direction as the conveyor belt.

The selection of a velocity within said range requires that the chemical reaction that takes place after the application of liquid mixture into the mold be taken into account. During the stay in the mold, liquid mixture foams and hardens. The height of the foam is influenced by the speed of the conveyor belt. Because the economy requires maximum product height, slower speeds are preferable during the foaming portion of the reaction to achieve such heights. The ratio of conveyor speed to product height is a useful criterion for evaluating the effectiveness of the method, ie the lower the ratio the more effective the method. According to the invention, this ratio can be reduced to the range from about 1 to about 3.

In order to reduce the tendency of the liquid reagents to flow back under the pouring opening and to help the zig-zags of reagent mixture to flow evenly together, it is usual to tilt a casting board with the surface under the opening different from horizontally such that the bottom liner slopes downwards in the direction of displacement, however, the angle of inclination of the casting board cannot exceed about 4.5 ° from the horizontal for the usual flexible polyether polyurethane foam- compositions without causing the reagent mixture to flow under previously deposited mixture, resulting in undesirably uniform foam The slope angle is different for different foam compositions, such as polyester polyurethane foams.

Problems arise when the bottom of the mold slopes downward along its entire length. Conventional continuous sheet molds are quite long, usually over 18 meters, to provide the long cure time of the foam. Building a movable shape of this length different from horizontal is considerably more expensive than building a movable shape of the same length that is horizontal because, for example, the building housing the sloping shape must be higher than normal ceilings. In addition, it is expensive to change the angle of inclination of the entire mold to compensate for different viscosities between different foam compositions. Thus, some continuous sheet molds have horizontal production lines for most of the length of the mold base, but have relatively short inclined pouring boards located under the pouring openings. The expansion and the rise of the foam usually take place on the sloping casting board.

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A second reason for providing the casting board at an angle to the conveyor belt is related to the shape of the cross section of the plate cast in the mold. As the foam expands and rises in mold 5, it contacts the side walls of the mold. When the liners of the sidewalls of the mold are moved approximately parallel to the bottom of the mold, the expanding foam experiences shear which resists rising along the sidewalls. This shear results in a rounding of the top of the plate to form a crown or comb of convex shape, much like a slice of bread. For most applications, such rounded areas are unusable and should be discarded as waste. Therefore, the better rectangular the cross-section of the slab, that is, the flatter the top, the more economical the casting process.

If the foam expands along the length, the liner of the bottom of the mold and the two liners of the side walls are displaced at an angle to each other, the sidewall liner may have a velocity component relative to the mold bottom in the direction of the expansion of the foam. This velocity component can outweigh the shear force that prevents the foam from rising. Guiding the liner from the bottom of the mold over an inclined casting board that intersects an inclined molding bottom band can provide such a compensating velocity component when foam expansion occurs along the length of the casting board and when mold sidewall liners are moved parallel to the shape-bottom band. The angle of cut, which usually leads to polyurethane foam sheets with the best rectangular cross sections, is about 10 ° for typical foam compositions and production conditions. Unfortunately, when the casting board is inclined 10 ° to horizontal, freshly deposited reagent mixture tends to flow down as discussed above, resulting in foam plates of uneven density and other imperfections.

35 Although it is possible to construct a continuous plate mold with a casting board different from horizontal 790 8 4 19 * 5> - with an angle of 4.5 ° and the conveyor belt cuts at an angle of 10 °, the conveyor belt must in this case, tilt upwards at an angle of 5.5 °. See, for example, the device of U.S. Pat. No. 3,325,823. As noted above, however, sloping movable shapes are more expensive than comparable horizontal shapes.

US Pat. No. 3,786,122 discloses a process for producing polyurethane foam sheets using a horizontal channel-shaped form having an inclined "drop plate" at its front end which has an angle significantly greater than 4.5 ° relative to horizontal. The problem of reagent mixture flowing down the inclined drop plate is avoided by pre-reacting the reagent mixture before it is placed on the drop plate. The pre-reaction step is performed in a trough that flares out on the top edge of the drop plate. Liquid foam reagents are introduced to the bottom of the trough and the foam generated is allowed to expand upward in the trough and overflow onto the drop plate. The foam continues to expand when 20 bö; is carried downward along the drop plate by a moving bottom sheet. Because the pre-foamed reagent mixture exiting the trough is more viscous than the initial liquid reagent mixture, the drop plate can tilt at a greater angle to horizontal than a casting board in a conventional polyurethane foam sheet form.

A further result of introducing pre-foamed reagent mixture into the mold is that relatively high foam plates can be produced compared to conventional methods. Savings result from producing high plates because the thicker the foam plate, the less the loss due to discarding crusts generally covering polyurethane foam moldings. With a conventional plate mold, if the rate of reagent mixture introduction is kept constant and the speed of movement of the molding liner is reduced, the height of the foam sheet tends to increase because more foam generating reagent is deposited per 790 34 19 6 lengthways. unit. However, when the speed of movement is reduced sufficiently, the expanding foam, especially the youngest and most liquid portion, becomes unstable and tends to slip and slide, resulting in cracks and other imperfections in the cured foam.

This problem of rising foam instability is alleviated in the process of U.S. Pat. No. 3,786,122 by introducing a moving foamed reagent mixture that is sufficiently viscous to be able to withstand a relatively steep slope of the casting board expansion completes. Thus, the height of the foam can be increased. In addition to the fact that higher foam plates can be molded by reducing the speed of movement of the mold liner, this method allows the use of plate molds shorter than those of conventional methods because the plate moves a shorter distance during curing time.

Certain problems arise when using the open trough of U.S. Pat. No. 3,786,122. For example, changing the width of the trough is difficult because foam deposits interfere with the resetting of liquid-tight closures. In addition, the trough opening is subject to partial blockage by cured foam deposits along the back and sides where the flow of pre-foamed reagent mixture stagnates. Such deposits loosen from time to time and pass over the baffle plate in the rising foam, causing annoying irregularities in the foam plate. A further difficulty is encountered when air bubbles are introduced into the bottom of the trough with the liquid reagents. These air bubbles generally remain trapped in the foam, leading to voids and other defects in the cured material.

U.S. Pat. No. 3,870,441 discloses an apparatus for the manufacture of polyurethane foam sheets using a horizontal channel-like shape similar to the apparatus of U.S. Pat. No. 790 04 19

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7k patent 3,786,122. Likewise, liquid foam reagents are introduced into the bottom of the trough and allowed to expand upward and eventually overflow onto a drop plate. The expanding foam travels across the drop plate to a conveyor belt 5 through a rectilinear moving bottom sheet. The improvement of it

U.S. Patent 3,870,441 is directed to a means of helping the expanded foam flow over the drop plate. This flow aid comprises rectilinearly moving sheets, substantially perpendicular to the bottom sheet, that continuously move around the perimeter of the channel-shaped shape including the perimeter of the trough. This improvement in the device of U.S. Pat. No. 3,786,122 does not eliminate all of the drawbacks noted above for the device of U.S. Pat. No. 3,786,122.

The present invention is directed to a method and an apparatus for the production of polyurethane foam products. The object of the invention is to use a unique laterally moving molding arrangement with the ability to realize high block heights and round block foams with a larger diameter. In particular, this molding arrangement comprises a first molding section with 20 diverging side walls, in particular a V-shaped molding section with diverging straight vertical side walls. The angle of the diverging sidewalls is not critical, but should be less than about 120 °, preferably within the range of 10 to 90 °. The intended angle is defined by imaginary lines from the top of the first mold section to the intersection of the diverging side walls with the parallel second side wall sections of the mold. Reaction mixture is deposited at the top of the V and completes its expansion almost shortly beyond the extremities of the V connected to parallel side walls of a conventional mold arrangement. A centrifuge, as described in U.S. Patent 4,158,132, can advantageously be used to deposit a partially expanded pre-foamed mixture of reagents. The mixture can be deposited on a segmented casting board. Use of the present invention results in low ratios of belt speed to product height compared to considerably higher ratios used in prior art methods and directions.

Various preferred embodiments of the invention are described below with reference to the accompanying drawings.

Figure 1 is a top plan view of an apparatus according to the invention used for the production of polymeric foam products using a V-shaped mold.

Figure 2 is a partial cross-sectional side view of the embodiment of Figure 1, wherein a conventional mixing head is used to deposit polyurethane reagents on a casting board inclined at an angle α to horizontal near the top of the V-section of the shape.

Figure 3 is also a side view, partly in section, of a modification of Figure 1, showing the segmented casting board with a first horizontal segment followed by a second segment inclined at an angle α to horizontal.

Figure 4 is also a side view, partly in section, of a modification of Figure 1, in which the polyurethane foam reagents are fed from a conventional mixing head to a pre-foaming device and then deposited on a device shown in more detail in Figure 4A, which device is suspended below the mixing head and above the casting shelf of a partially expanded pre-foamed mixture of reagents.

Figure 4A is a front view of the device in Figure 4 on which the partially expanded pre-foamed reagent mixture is deposited.

Figure 5 is also a side view, partly in section, of a modification of Figure 4, showing a segmented casting board with a first and a second segment inclined at angles ctj and relative to horizontal, respectively.

Figure 6 is a front view of the modification of Figure 1 in which the polyurethane foam-forming reagents 790 84 19 9 are fed into a cone-bottomed pre-foaming member and then deposited on the casting board by outflowing from the conical pre-foaming member as a partially expanded pre-foamed reagent mixture.

Figure 6A is a front view of the cone shaped foaming member used in the device of Figure 6 used in conjunction with an upstream or bottom centrifuge.

Figure 1 shows an apparatus 10 for producing products from free-rising polyurethane-10 foam. The foam product will have a substantially rectangular cross-section (see U.S. Patent 3,325,823); however, this device could be modified to produce a substantially circular cross-section foam product according to U.S. Pat. No. 3,325,573. This device 15 is suitable for use in the method according to the invention. The device includes a conduit 11, which may be stationary or reciprocating depending on the need to distribute the premixed reagents near the apex of the V-shaped first portion 12 of a continuous rectilinear form 13. The latter second portion of mold 13 comprises a conventional arrangement for producing a product of the desired shape with a bottom consisting of a conventional conveyor belt to transport the expanding and hardening polyurethane foam and parallel side walls which may be either moving or stationary. The V-shaped portion includes the sidewalls 14 of the first molding portion which diverge and cannot be parallel or convergent. These side walls of the first molding portion of the V-shaped portion meet at their ends with the parallel side walls 15 of the second molding portion of the mold 13.

Figure 2 shows lines 16 and 17 which simultaneously transport a mixture of polyurethane foam-forming reagents to a conventional mixing head 18 connected to line 11 for depositing premixed reagents on the casting platform 19. A liner 20 for the bottom of the mold made from a flexible web, such as Kraft paper, is fed from a roll shown in the drawing and passed over the casting board 19903419 10 on a mold base surface lacquer 21 of a conveyor belt 22.

First and second side wall liners 23 and 23A, also made of a flexible material, such as Kraft paper, are guided along opposed guide members 24 and then ill move over the side walls 14 of the V-shaped first mold section 12 and then along the side walls 15 of the second mold portion of mold 13. The side wall liners 23 are flush against the mold side walls 14 and 15 by the pressure of the expanding premixed polyurethane foam-forming reagents.

The sidewall liners and bottom liner of the mold define a channel-shaped mold for pouring foam products, which may have substantially rectangular or nearly circular cross-sections. Means are provided for guiding and transporting the sidewall liners and the bottom liner in a parallel manner.

Of course, the translation speed of the three liners should be substantially equal to the translation speed of the assembly line 22.

Pouring board 19 can be substantially flat or curved and makes an angle α with the horizontal plane. The angle of inclination cs can be adjusted to accommodate variations in the viscosity of the mixture deposited thereon.

Although a single angle casting board is shown in Figures 1 and 2, it may be beneficial in some applications to use casting boards with more than one segment, such as that shown in Figure 3, with each segment inclined at a different angle to horizontally, or, as in Figure 3, with a first segment disposed horizontally. Figure 3 shows a casting board consisting of two segments, a first horizontal segment 25 located in the vicinity of the pipe 11 and a second inclined segment 26 connecting to the first segment 25 .. and adjacent to the conveyor 22 inclined at an angle os to the horizontal. Such a casting board arrangement has been used to make foam products of substantially rectangular and substantially circular cross sections. Other segmented casting boards are, of course, within the scope of the invention.

Figure 4 depicts a further modification of 7908419 4 11 Figure 1 using a pre-foaming device 27 used in preparing a partially expanded pre-foamed mixture of polyurethane foam-forming reagents to be deposited on casting board 19. The pre-foaming device 27 is shown as a top centrifuge, such as that described in U.S. Patent 4,158,132. Other pre-foaming devices useful in the practice of the present invention include the conical pre-foaming device alone or in conjunction with the bottom centrifuge shown in Figures 6 and 6A, again referring to U.S. Patent 4,158,132 in this regard.

As previously described, lines 16 and 17 simultaneously transport polyurethane foam reagents into the mixing head 18. Premixed reagents exit from the mixing head 18 through line 11, which flows into the pre-foaming device 27, which in this case is shown as a top centrifuge.

When skewer 27 includes a top centrifuge, a variable speed electric motor 28 is used to rotate the holder 29 by a drive belt 30. A motor speed controller 31 varies the speed of the motor 28. Accordingly, mixed reagents enter through the inlet tube 11. rotary and pressurized container 29 to form partially expanded polymer blend 32.

A gas atmosphere can be maintained above mixture 32. The pressure of this atmosphere is controlled to a predetermined value by a conventional gas pressure regulator 33 which is connected to container 29 through conduit 34. This pressure forces the partially expanded mixture through flexible conduit 35 to a dispensing nozzle 36. The flexible conduit 35 brings the partially expanded mixture from the interior of the container 30 29 to the top of the V-shaped portion 12 of mold 13. Nozzle 36 is located above the pouring board 19 near the top of the V-shaped part of the mold. Advantageously, a combination of a circular reservoir 37 and a baffle plate 38 is placed under the nozzle 36; this combination is shown in more detail by Figure 4A. The nozzle can be stationary or reciprocated across the width of the top of the shape 790 84 19 12 V-shaped portion 12 by conventional reciprocating means. An edge of the casting board 19 projects against a surface of a conventional walking hand 22, which is used to form a bottom surface 21 of the mold. This surface is preferably substantially horizontal. Incidentally, the device operates in a manner described above with respect to Figure 1.

The combination of circular reservoir 37 and baffle plate 38 shown in Figure 4A is used to further control the spread of the partially expanded pre-foamed reagent mixture on the casting board 19. This combination also includes a lip 39 over which the partially expanded pre-foamed reagent mixture passes before entering the casting board 19.

Although a single segment casting board 19 is shown in Figure 4, it may be beneficial in certain applications to use a multi-segment casting board, such as that shown in Figure 5, with each segment inclined at a different angle from the horizontal flat. Figure 520 shows a casting board consisting of two segments, a first segment 40 located near the spray opening and having an angle øj with respect to the horizontal plane, and a second segment 41 connecting to the first segment 40 and approaches the conveyor belt 22, at an angle α ^ to 25 from the horizontal. Again, further multi-segment casting boards are within the scope of the invention.

Figure 6 shows a front view of a modification of the device shown in Figure 1, in which a conical bottom foaming device 42 is used to apply the partially expanded pre-foamed mixture of reagents to the casting board 19. In this conical bottom pre-foaming device (shown separately in Figure 6A), the partially expanded pre-foamed reagent mixture is introduced from under the casting board 19 through line 43; thereafter, the mixture exits from the opening 44 and flows into the reservoir 45, formed by the back and side walls 46 and the anterior return 790 84 19 4.

13 plate 47. Thereafter, the partially expanded pre-foamed reagent mixture moves on the casting board 19, above which passes a mold bottom liner 20 made of a flexible material such as Kraft paper. The liners 23 and 23a of the first and second side walls, also made of a flexible material such as Kraft paper, are guided along opposing guides 24 and 24a. The bottom liner 20 and sidewall liners 23 and 23a then pass over the surface 21 of the conveyor belt 22.

Figure 6A separately depicts the conical bottom skimmer used in Figure 6. Figure 6Δ also includes a representation of a bottom centrifuge 48 which has been advantageously used in combination therewith.

In accordance with the method according to the invention, a first component A and a second component B are produced

simultaneously mixing head 18 in. These components are premixed using a conventional mixing head and can either be deposited directly on casting board 19 through conduit 11 or can enter pre-foaming device 27 where a partially expanded pre-foamed mixture 32 is formed and then deposited on nozzle 36. casting board. Line 11 and nozzle 36 can be stationary or reciprocating. The mixture is normally deposited at a constant rate near the top of the V-shaped portion 12 of form 13. The components of the mixture continue to react, expand and cure to form a polyurethane foam product. The deposited mixture continuously moves along the mold liners and the conveyor belt. The conveyor belt normally moves at a constant speed. Typical foam compositions used in the present invention are exemplified below.

The following examples are illustrative of the ease with which polyurethane foam products can be produced by the method of the present invention. Example I

A polyurethane foam sheet was cast continuously using a conventional mixing head, 790 34 19

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shown in Figure 1. The following recipe was mixed in the cup and deposited near the top of the V-shaped portion of the mold:

Component A Wt% Wt% g / min 5 Dow Polyol CP 3140 (3700 -MV 65.05 65.05 3,470 copolymer of ethylene oxide and propylene oxide, from Dow Chemical Company)

Master Batch I: 10 Dow Polyol CP 3140 32.45 BP 2370 (Silicone surfactant from Goldschmidt Chemical Company) 0.75

Water 4.00 15 A-1 (70% solution of bis (dime thylaminoethyl) ether in dipropylene glycol, from Union Carbide Company 0.10 37.30 37.30 1.990 20 Master Batch II:

Dow Polyol CP 3140 2.50 C-6 (33-1 / 3% T-9) 33-1 / 3% solution of stannous octoate in D.O.P. from Witco Chemical 25 Company) 0.75 3.25 3.25 173

Component B

TD-80 (Toluene Diisocyanate 80/20 2.4 / 2.6 Isomer Ratio, from Mobay Chemical) 50.00 50.00 2,667 155.60 8,300

The ingredients of component A, which contains the polymer compound, were premixed and pumped into the mixing head with a single stream. Component B, which includes the toluene dixso-35 cyanate component, was pumped into the cup separately and simultaneously. Both components were mixed at ambient temperature. The feed rate of the mixed components was 8300 g per minute. The resulting mixture was deposited at a constant speed near the top of the V-shaped portion of the mold. The side walls of the V-shaped portion were 112 cm long and were located 63.5 cm apart, the point where they joined the side walls of the second molding portion. The angle between the divergent side walls is therefore in this case about 33 °.

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The expanded mixture moved downward along a segmented casting plan similar to that shown in Figure 3.

The first segment of the casting board had an angle of 0 ° to the horizontal plane, while the second segment inclined at an angle of 17 ° to the horizontal plane. The segmented casting board ended on a conveyor belt sloped upward at an angle of 3 ° from the horizontal. The constant speed of the conveyor belt was 131 cm per minute. In accordance with Figure 3, the shape was channel-shaped with parallel sidewalls lined with Kraft paper, moving at the same speed as the conveyor belt. A substantially rectangular polyurethane foam product was produced with a density of 26.4 kg / m and a height of 48.8 cm. The ratio of the conveyor belt speed to the product height was about 2.7.

Example II

Example I was repeated using a slower feed rate and a different reagent composition: Component A Wt% Wt% g / min.

Dow Polyol CP 3140 77.13 77.13 3.470 20 Master Batch I:

Dow Polyol CP 3140 20.37 BF-2370 0.75

Water 4.00 A-I 0.10 25 25.22 25.22 1,135

Master Batch II:

Dow Polyol CP 3140 2.50 C-6 (33-1 / 3% T-9) 0.75 3.25 3.25 146

30 Component B

TD-80 50.00 50.00 2,249 155.60 7,000

The feed rate of the reagents was 7.0 kg / min, and the conveyor speed was 104 em / min. A good foam product was produced with a rectangular cross-section and a height of 40.5 cm. The ratio of the conveyor belt speed to the product height was about 2.6.

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Example III

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A polyurethane foam sheet was continuously cast using a centrifugal fore-foam device similar to that shown in Figure 4. The following composition was mixed in the fore-foam device:

Component A. Wt% Wt% g / min.

Dow Polyol CP 3140 75.00 75.00 7,160

Master Batch I:

Dow Polyol CP-3140 22.50 10 BP 2370 0.80

Water 4.00 A-5 (0.03 15 27.33 27.33 2,609

Master Batch II:

Dow Polyol CP-3140 2.50 C-6 (33-1 / 3% T-9) 0.57 3.07 3.07 293

20 Component B

TD-80 50.00 50.00 4,773 155.40 14,835

The ingredients of component A, which includes the polyol component, were premixed and pumped into a conventional mixing head as a single stream. Component B, which includes the toluene diisocyanate component, was pumped into that cup separately and simultaneously. Then both components were mixed at ambient temperature. The mixed components were then fed to a centrifugal pre-foaming device to form a partially expanded polyurethane foam blend. This mixture was deposited near the top of the V-shaped portion of the mold at a constant feed rate of 14.835 kg / min.

The side walls of the V-shaped portion of the mold were 152 cm long and were located 117 cm apart; the angle between the side portions of the V-shaped shape is therefore about 45 °. The casting board on which the partially expanded mixture was deposited comprised three segments: a first segment inclined at 15 °, a second segment horizontal and a third segment with 7908410 17 inclined at 13 °. The casting board ended up on a conveyor belt which sloped upwards at an angle of 3 °. The latter portion of the mold was channel-shaped with parallel side walls spaced about 117 cm. The mold was lined with Kraft-5 paper moving at a constant speed. Using the above composition and feed rate, a number of experiments were conducted in which the conveyor speed was varied. The results are shown below:

Table 10 Experiment Belt speed (V) Product height (H) Ratio no. (M / min.) C (cm) (Vc / H) 1 0.84 43.6 1.92 2 0.89 41.0 2.18 3 0.92 42.4 2.18 15 4 0.92 40.9 2.25 5 1.02 42.0 2.43 6 1.02 43.1 2.36 7 1.02 41.0 2.48 8 1.10 42.0 2.62 20 9 1.25 44.7 2.79 10 1.33 45.7 2.92

The ratio ranged from about 1.9 to about 2.9.

Example IV

Experiment I was repeated using a similar polyurethane recipe with an increased feed rate of 14.8 kg / min:

Component A Wt% Wt% g / min.

Dow Polyol CP 3140 75.00 75.00 7,160 30 Master Batch I:

Dow Polyol CP-3140 22.50 BF 2370 0.80

Water 4.00 A-5 0.07 35 27.37 27.37 2.613

Master Batch II:

Dow Polyol CP-3140 2.50 C-6 (33-1 / 3% T-91) 0.57 3.07 3.07 299 790 8 4 19 18

Component B

TD-80 50.00 50.00 4,773 155.44 14,845

The side walls of the V-shaped portion of the mold were 152.5 cm long and 117 cm apart at the point where they joined the second portion of the mold (ie α = approximately 45 °). The expanded mixture moved down a segmented casting board: a first segment inclined below 15 °, a second segment horizontal, a third segment inclined below 3 ° and a fourth segment below 18 °. The segmented casting board ended up on a conveyor belt which sloped upwards at an angle of 3 °. The conveyor belt speed was 1.22 m / min. and the height of the rectangular foam sheet was 39.4 cm, which resulted in a ratio of the belt speed to the product height of about 3.2.

Example V

Example III was repeated for the production of a round block using a tunnel-shaped part for the last part of the mold.

20 The following polyether recipe was mixed in the pre-foaming device:

Component A Wt% Wt% g / min.

Dow Polyol CP-3140 64.968 64.968 3.470

Master Batch I: 25 Dow Polyol CP-3140 32.522 BF 2370 0.800

Water 4,000 A-5 0.030 37.352 37.352 1.995 30 Master Batch II:

Dow Polyol CP-3140 2.50 C-6 (33-1 / 3% T-91) 0.59 3.070 3.070 164

Component B

35 TD-80 50,000 50,000 2,671 155,390 8,300

The side walls of the first molding section were 112 cm long and were 58 cm apart. The casting board was segmented, with a first segment sloped below 7908419 * 19 6 ° and a second segment Mlend below 15 °. The casting board ended up on the conveyor belt which sloped upwards at an angle of 3 °. Circular foam products are obtained with a diameter of 56 cm. The conveyor belt speed varied from 65 to 127 cm per 5 minutes with associated ratios of about 1.1 and about 2.2, respectively.

Overall, it should be noted that certain free-rising polyester-derived polyurethane foam recipes may be too sensitive to mechanical stresses to be used in the present invention.

It is not intended to limit the present invention to the specific embodiments described above. Other changes may be made to the method and the device as specifically described above without departing from the scope of the invention, and it is intended to include all other embodiments, alternatives and modifications in accordance with the invention .

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Claims (19)

A method for continuously forming free-rising polyurethane foam in a continuous laterally moving open-top mold at a given bottom-belt speed by depositing a polyurethane foam-forming mixture of reagents at a given feed rate on a casting board, characterized in: that the height of the molded flexible polyurethane foam product obtained is increased by (1) depositing the polyurethane foam-forming mixture of reagents near the top of a first mold portion of the laterally moving mold, which first portion of the laterally moving mold divergent first has side walls which form an angle therebetween of more than about 10 ° and less than about 120 ° and which meet at their ends with the parallel second side walls of a second portion of the moving shape, and (2) substantially complete proofing the polyurethane foam-forming mixture of reagents after passing through the first part lte of the moving form. Method according to claim 1, characterized in that the ratio of the speed of the conveyor belt to the height of the foam product is from about 1 to about 3. A method according to claim 1, characterized in that the polyurethane foam-forming mixture of reagents is deposited in partially expanded pre-foamed form between the divergent vertical side walls of the first mold section. A method according to claim 3, characterized in that the polyurethane foam-forming mixture of reagents is deposited in a partially expanded pre-foamed form from a centrifuge pre-foaming device. 5. A method according to claim 3, characterized in that the polyurethane foam-forming mixture of reagents is deposited in a partially expanded pre-foamed form from a cone-shaped foaming device. 6. Method according to claim 1, characterized in that the polyurethane foam is a polyester-derived polyurethane foam. A method according to claim 1, characterized in that the deposited reagent mixture moves over a segmented casting board with a horizontal first segment. 8. Method according to claim 1 or 7, characterized in that the deposited mixture of reagents moves over a casting board with at least one segment which slopes downwards to the second part of the moving mold. Method according to claim 1, characterized in that a continuous shape is formed with a substantially rectangular cross-section. Method according to claim 1, characterized in that a continuous shape is formed with a substantially circular cross section. 11. An apparatus for producing free-rising polyurethane foam, comprising: (a) means for mixing liquid polyurethane foam-generating reagents; (b) means for depositing the mixed reagents in a laterally moving form; and (c) an open top continuous form, comprising: (3) a bottom belt conveyor that extends laterally to displace a foam product; (2) a laterally moving shape whose bottom surface is adjacent to the belt conveyor; and (3) a casting board disposed between side walls of the mold with a raised edge near the barrier member extending to the mold bottom surface; characterized in that a stationary barrier is provided for depositing the mixture of polyurethane foam-forming reagents near the top of a first top-open mold section with diverging sidewalls sandwiched therebetween by more than about 10 and less than about 120 ° shapes and which meet at their ends with the parallel side walls of a second portion of the moving mold. Device according to claim 11, characterized in that a pre-foaming device is present in combination with the depositing device such that upon deposition the mixture of polyurethane foaming reagents is in a partially expanded pre-foamed state. 13. Device according to claim 12, characterized in that the pre-foaming device is a centrifuge. Device according to claim 12, characterized in that the pre-foaming device is a cone-shaped bottom pre-foaming device. 15. Device as claimed in claim 11, characterized in that the casting board is segmented. Device according to claim 15, characterized in that the casting board has a first horizontal segment in the vicinity of the depositing member followed by an inclined second segment. Device according to claim 11, characterized in that the second mold part is rectangular. Device according to claim 11, characterized in that the second molding portion is circular. 19. Methods, devices and products 20 substantially as described in the description and / or the examples. // 790 84 19 ut l ~ i