JP2002506660A - Method and apparatus for producing mineral fiber based growth medium, plant growth medium and use thereof - Google Patents

Abstract

(57) Abstract: A method for producing a plant growth medium having a density gradient, comprising providing a first web containing a mineral fiber material and a hardenable binder, wherein the first web is provided in at least one longitudinal extension zone. Compressing the pressure so as to increase substantially continuously in the transverse direction of the zone, forming a second web by laminating the first web itself, and optionally compressing the second web. And curing the binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for producing a mineral fiber based plant growth medium having a density gradient.

[0002]

[Prior art]

It is known in the art to use products containing mineral fiber materials as plant growth media. These plant growth media have the advantage that they are very porous, thus allowing the plant roots to ingest the necessary water, nutrients and air. Typically, the fibers take up about 5% by volume or less of the medium and ideally provide about 95% by volume of air, water and / or phytonutrients to the roots. Mineral fiber-based plant growth media is generally lightweight and therefore easy and economical to transport, and such media further degrades when used for long-term plant root presence. Is strong enough to resist and chemically inert. Absorbing and retaining water is one of the main functions of a plant growth medium. If the water holding capacity of the medium is too low, water will pass through the medium immediately upon watering, and the plants will have to dry between watering or watering very frequently. Instead, large amounts of waste water will be produced. On the other hand, if the water holding capacity of the plant growth medium is too high, the plant may not be able to pump water from the medium, and furthermore, the plant roots may not be able to breathe due to the lack of air in the medium.

[0003] It is known from DK 170 034 B1 that there are plant growth products based on mineral fiber materials with advantageous water holding capacity. These products have a density or coarseness gradient in the height direction of the product, with the fibers having the highest or lowest density fibers at the top and the lowest density at the bottom. Has low or highest roughness fibers. Thus, the possibility of reducing the gravitational effect on water by capillary action has been proven. By increasing the medium density in the height direction or reducing the roughness of the medium, the pore size is generally reduced, so that again the capillary action is again increased, so that water is Will be raised. According to DK 170 034 B1, such advantageous plant growth media were produced separately, in multiples, each having an increased surface mass and a reduced fiber roughness compared to the previous layer. It can be obtained by stacking and combining glass fiber layers. However, this is a difficult method to produce such a plant growth medium. Furthermore, in order to obtain such a product consisting of a plurality of separately manufactured layers having sufficient adhesion between said layers, it is necessary to use a certain amount of binder between the layers, The ability to diffuse water between the layers is impaired, and the production cost increases.

[0004] US Pat. No. 5,009,030 discloses a similar, fertilizer-free plant growth support that exhibits a controlled water gradient across the thickness of the product. The water retention gradient is obtained by the density and compactness gradient in the product. According to the literature, varied densities and densities are obtained by superposing a plurality of glass wool web layers, each having a different density or densities. Acceptable water retention gradients are obtained according to US Pat. No. 5,009,030, but their preparation is rather difficult because multiple mineral fiber web layers must be combined into one. These layers must also be adhered to each other to provide sufficient strength for delamination, and due to the placement of the binder between such different layers, water and The transfer of other substances can be impaired. Further, the product itself provides only a gradual water retention gradient, but not a continuous gradient.

[0005]

[Problems to be solved by the invention]

Accordingly, it is desirable to provide an improved manufacturing method that provides an improved mineral fiber based plant growth medium.

[0006]

[Means for Solving the Problems]

The object is to provide a first web comprising a mineral fiber material and a binder, wherein the first web is increased in at least one longitudinal extension zone in a manner substantially continuous in the transverse direction of the zone. Compressing to produce a compression gradient in that direction,
Forming a second web by stacking the first web itself by laying the first web in a plurality of layers in the transverse direction of the second web, and dividing the second web to form a plant growth medium This is achieved by the method of the present invention, characterized in that:

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides a method for compressing the first web to cure the binder in the product.
It is based on the finding that compression can be essentially maintained until it is hardened or hardened. Thus, it is possible to compress not only one part of the first web but also another part and to obtain a product with a variable density. Furthermore, knowing which part of the first web to place where, when stacking the first web itself,
It is possible to predict where the higher density parts will be in the final product. A typical and preferred method of stacking the first web itself is by a pendulum-type distributor known in the art. In this way,
The second web is formed by a plurality of slightly displaced layers of the first web that are spread transversely to the longitudinal axis of the second web. The second web may be compressed to cure the binder in the product. The second web cured in this manner may be cut into a plurality of products having substantially any desired shape. Preferred methods for spreading mineral fiber webs with a pendulum-type distribution are disclosed in WO 88/03509 or WO 97/03509.

According to this method, one end of the first web finally forms the top layer of the final product, and the other end forms the bottom layer of the product. Therefore, the density gradient in the height direction (from bottom to top) of the final product can be obtained by compressing the first web while continuously increasing the compression force in the direction from one end to the other end. The method according to the invention is simpler in comparison with the conventional method in terms of the number of steps of operation. Thus, the method can be performed in a continuous process, and no stacking and / or bonding steps are required. Furthermore, an advantage of the method of the invention is that the absolute density and density gradient profile can be controlled in detail by simply adjusting the pressure applied by the pressurizing means. Compression can be performed by any means capable of producing a substantially continuous compression gradient. Compression can be effected, for example, by a conveyor belt, one or more cylindrical and / or conical rollers having axial suspensions with or without angles to the surface of the first web. Preferably, the web is compressed by a plurality of rollers. Preferably, a plurality of rollers, each having a separate suspension, is used. By applying a plurality of separately suspended compression means, it is possible to control the compression force applied separately by each means, and thus to quickly switch between the compression profile and / or configuration of the compression zone. it can.

Particularly preferably, a roller having a diameter of 5 to 70 cm, more preferably 15 to 50 cm, and still more preferably 20 to 40 cm is used. If the roller is too small, the first web will accumulate on the roller surface and eventually the method must be stopped for cleaning. Rollers that are too large are generally difficult to handle. Any number of rollers can be used to compress the first web, preferably using rollers having a width of about 30-600 mm, more preferably about 50-300 mm, and even more preferably about 80-150 mm. It has proven to be advantageous. Rollers are applied in both the longitudinal and transverse directions of the web in a side by side manner.
) Or in a displaced manner. The rollers are arranged in two alternating rows in the longitudinal direction of the first web, in which the rollers are arranged in parallel in the transverse direction of the web, with a spacing between the rollers. Arranging such that the spacing between the rollers of one row is covered by the rollers of the second row has proven to be particularly advantageous.

According to a preferred embodiment of the method of the present invention, it has proven advantageous to use rollers or wheels which are somewhat elastic. Preferred rollers include a flexible suspension and / or a flexible coating (eg, a type of tire). In this way, the rollers can compensate for the unevenness of the first web. Furthermore, the use of rollers having such resilient surfaces or suspensions can reduce the damage that occurs on the first web due to compression in that there are fewer broken or broken fibers. However, it has proven particularly advantageous to use rollers having a smooth, non-tacky pressure, for example with a metal or polytetrafluoroethylene surface. This can prevent the first web from sticking to the rollers, which would otherwise be a serious problem during the pre-compression step. Compression can be performed in one or more operations using any number of compression means. The density gradient profile may be linear or non-linear, depending on the shape or operation of the compression means. The surface of the compression means may be smooth or have a certain pattern.

Naturally, only a part or a plurality of parts of the first web can be compressed to obtain a product having a higher density gradient in the height direction. Further, the second web may be divided into more products having one or more density gradients. However, it is preferred to create a density gradient over the entire width of the first web, ie, to compress the entire web and thus create a density gradient throughout the height of the second web. It should be noted that the advantages of the present invention may be obtained by any of the methods of the type described above, wherein at least a portion of the first web is provided, for example, by a pendulum-type distribution or according to EP 0 297 111 B1. With the cut-off into sections as described, the first web itself can be compressed before stacking itself under the formation of a second web, which can be optionally compressed and finally cured; A substantially continuous density gradient in the height direction of the final product can be obtained.

When the web is compressed using rollers, one side of the zone is about 0-400 k
g / m (roller width), preferably 0 to 250 kg / m and more
kg / m, on the other side about 500-3000 kg / m, preferably 750
To 2500 kg / m and more preferably 1000 to 2000 kg / m.
Preferably, the web is compressed. Compressing the first web using a continuous compression gradient not only results in a product having the desired density characteristics. By applying a pressure within the above range, a certain amount of fibers can be decomposed when subjected to a high pressure, and substantially no fibers can be decomposed when subjected to a low pressure. As a result, a continuous gradient of fiber roughness can be provided that further enhances the water retention capacity of the product in terms of controlled capillary action. Product density is obtained, the top surface, preferably 40~180kg / m ^3, more preferably 50~120kg / m ^3, the bottom surface, preferably 10 to 12 0 kg / m ^3, more preferably 30~120kg / M ³ , and the product
Preferably 30~180kg / m ^3, more preferably preferably from 30~120kg / m ³ and even may have an average density of 40 to 80 kg / m ^3.

According to a preferred embodiment of the method of the present invention, preferably 0.5 to 10% by weight,
More preferably 0.5 to 5%, and even more preferably 1 to 3% by weight of the binder is added to the first web. All binder weight percentages are based on the final product. Further, in a preferred embodiment of the method of the present invention, the second web is moved in the vertical axis direction.
That is, for example, as disclosed in US 4,632,685, CH 620,861 or US 2,500,690. The products obtainable by the method of the invention are particularly suitable for use as plant growth media, but can also be used as heat insulators or sound insulation. The invention also relates to a mineral fiber based plant growth medium obtainable by the method of the invention.

The product obtainable by the process of the present invention is superior to the prior art in that it does not include the assembly plane and its density gradient is substantially continuous rather than stepwise. Things. The products of the present invention can be manufactured to meet almost any requirement in terms of water retention, air penetration and robustness. The products of the present invention can therefore be manufactured to meet the requirements of a comprehensive variety of plants, including tomatoes, cucumber, rose and kalanchoe. The invention further relates to the use of the products obtainable by the method of the invention for growing plants, in particular the plants mentioned above, and to an apparatus for performing the method of the invention. Accordingly, the apparatus of the present invention is a means for providing a first web comprising a mineral fiber material and a binder, a means for compressing the first web in at least one longitudinal extension zone, the first web comprising: The means for forming a second web, wherein the means for compressing is such that the pressing force rises substantially continuously in a direction transverse to the zone to produce a compression gradient in the direction, Means for allowing the first web itself to overlap by laying the first web in a plurality of layers transverse to the second web, and means for splitting the second web to form a plant growth medium. Features.

The invention will be further described with reference to the figures. FIG. 1 shows the density change in the width direction of the first web after compression using a plurality of rollers each having a width of about 100 mm, where each axis load is compressed at about 0 to 1000 kg / m. Is what it is. After the formation of the second web by pendulum movement, a substantially continuous density gradient spreads in the height direction of the second web. Accordingly, products having such a substantially continuous density gradient may be cut from the second web. FIG. 2 shows the product of the present invention, which has a relatively low density at the bottom, a relatively high density at the top, and a substantially continuous density gradient from bottom to top.

FIG. 3 shows a process of manufacturing a second web from which a product is finally cut. The first step involves the formation of mineral fibers from the mineral-forming melt, which is produced in a furnace 1 and from a spout 2 of the furnace 1 Is supplied to a high-speed rotating spinning wheel 3 (four in total) supplied as a mineral fiber forming molten stream 4. Since the mineral fiber forming melt stream 4 is supplied to the spinning wheel 3 in a radical direction, the gas stream is simultaneously supplied to the high-speed rotating spinning wheel 3 in their axial direction, As indicated by reference numeral 5, this results in the formation of individual mineral fibers, bundles or small bundles of mineral fibers, which are discharged or sprayed from the high-speed spinning wheel 3. The gas flow constitutes a so-called temperature treatment gas flow, usually a cooling gas flow. Mineral fiber spray 5
Are collected on a continuously operated first conveyor belt 6 forming a first mineral fiber web 7. The thermosetting binder can also be used either directly on the first mineral fiber web 7 or at the stage of releasing the mineral fibers from the spinning wheel 3, i.e. at the stage of forming the individual mineral fibers. It can be added to the mineral fiber web 7. The binder may of course be a binder known for use in combination with mineral fibers, ie a thermoplastic binder. The first conveyor belt 6 consists of two conveyor belt sections, as is evident from FIG. The first conveyor belt section is inclined with respect to the horizontal and with respect to the second conveyor belt section that is substantially horizontal. The first section comprises the collection section, while the second section
The sections make up the transport section. It can, of course, be manufactured by any method known in the art. The conveyor belt used to collect the fibers is preferably of foraminous type and is provided with means for suctioning air (not shown) through the belt to facilitate the lying down of the fibers. . This is to ensure better dispersibility of the fibers, i.e. in terms of low fiber density spots with high airflow through the belt which allows more fibers to lie there. The uniformity of the web 7 is improved.

The compression of the first web 7 is skewed from one side of the web to the other, so that the rollers 8 provide a continuous compression gradient in the full width direction of the first web.
The first web 9 after longitudinal compression is maintained such that substantial compression is maintained, ie, compression on the other side is maintained higher than on one side. The inclination of the rollers can, of course, be adjusted to provide the desired compression profile. Similar effects can be obtained by using multiple rollers or bands and / or conical rollers. In most cases, it is preferred to compress the first web as far as possible along one side, essentially in a zone which is not at all along the other side. Various known means, such as compression aids, may be used advantageously to ensure that an accurate density gradient is maintained / obtained in the final product. The first section of the first conveyor belt 6 constitutes a collecting section, as described above, while the second section of the conveyor belt 6 constitutes a transfer section, thereby having a continuous compression gradient in the width direction. A first mineral fiber web is transferred to second and third continuously operated conveyor belts indicated by reference numerals 10 and 11, respectively, said two belts being synchronized with the first conveyor belt 6. Activated to clamp the compressed first mineral fiber web 9 between two adjacent surfaces of each of the second and third conveyor belts 10 and 11.

Each of the second and third conveyor belts 10 and 11 communicates with a fourth conveyor belt 12 which constitutes a collecting conveyor belt, on which the second and third conveyor belts 10 and 11 are connected.
Each of the conveyor belts 10 and 11 is swinging transversely across the fourth conveyor belt 12 above the surface of the fourth conveyor belt 12,
A second mineral fiber web 13 is collected. Thus, the second mineral fiber web 13 is manufactured by stacking and arranging the first mineral fiber webs 9 generally in the transverse direction of the fourth conveyor belt 12. As shown in FIG. 3, the compressed first mineral fiber web 9 to the second mineral fiber web 1
By producing No. 3, the density is low at the bottom but high at the top
A second web is produced that varies substantially continuously in the height (thickness) direction. Bricks cut from the preferred cured second web are unique for use in plant growth media due to the controlled water retention gradient, ie, improved water retention capacity. As used herein, the term first mineral fiber web refers to a newly formed mineral fiber web having a typical height (thickness) of 3-7 cm, which comprises a plurality of corresponding mineral fiber webs. It is intended to provide a second web sandwiched between the first layers and preferably composed of the same web. A particularly preferred method of obtaining such first and second mineral fiber webs is disclosed in WO 97/01006.

The term water retention capacity, as used herein, is measured in% by volume,
Means the product's ability to retain water. As used herein, the term mineral fiber based plant growth medium refers to any product suitable as a host for plant roots, wherein the product comprises a substantial amount, preferably about 1-10% by volume, More preferably, it contains mineral fibers in an amount of about 2-5% by volume. The plant growth medium of the present invention may contain a plurality of components near the mineral fibers, for example, organic compounds such as lignite, clay and coco peat. The term mineral fiber as used herein refers to all types of artificial mineral fibers such as rock, glass or slag fibers, in particular fibers used in materials for thermal or sound insulation purposes, and cement fillers. As a plastic or other material, or it is used as a medium for plants. The term binder as used herein refers to any material suitable as a binder in mineral fiber materials for the above products, such as phenol formaldehyde urea, acrylic acid copolymer, resorcinol, furan or melamine resin, and the like. Including. Such a binder is preferably supplied to the mineral fiber material in the form of an aqueous suspension. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0020]

【Example】

Example 1 Mineral fibers were obtained by spinning in a spinning chamber and had a width of about 1.8.
m and deposited on a conveyor belt under formation of a first web having a surface mass of about 500 g / m ² . The binder, including phenol formaldehyde urea in an aqueous suspension, was continuously distributed to the fibers in the air in the spinning chamber before setting the fibers on a conveyor belt. The binder was added in an amount corresponding to a final phenol formaldehyde urea concentration of about 3% in the final product. The first web must be of sufficient width, at a pressure of 0 kg / m against one end of the first web and 1000
kg / m and a substantially linear interpolated compression ratio between these two values between the two ends of the first web.
Compressed by a cylindrical roller suspended to press in e). The first web was spread by a pendulum-type distribution under formation of a second web about 2 m wide, and the second web was observed to include about 12 layers of the first web in its cross section. The obtained second web was compressed to a height of 100 mm and cured in a curing furnace. Finally, a plant growth medium was obtained by cutting the second web thus hardened into a desired size. The plant growth medium produced by the method of this example had a continuous density gradient of 35 kg / m ³ at the bottom and 130 kg / m ³ at the top. The plant growth medium of the present invention did not show delamination and had excellent water retention / dispersion ability.

[Brief description of the drawings]

FIG. 1 shows a density gradient in a width direction of a first web.

FIG. 2 shows a product of the invention.

FIG. 3 shows a preferred method for producing the plant growth medium of the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR , BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS , JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Kirkebeek Jergen Denmark 2680 Sollede Strand Mosea Helvey 28 F term (reference) 2B022 AA05 BA06 BB02 DA19 4L047 AA00 AA06 BA15 BC07 BC12 BC14 CC16 EA22

Claims (13)

[Claims] 1. A method for producing a mineral fiber based plant growth medium having a density gradient, comprising: providing a first web comprising a mineral fiber material and a binder, wherein the first web is in at least one longitudinal extension zone. Compressing so that the applied pressure rises substantially continuously in the transverse direction of the zone to produce a compression gradient in the direction,
The second web is formed by stacking the first web itself by laying the web in a plurality of layers in the transverse direction of the second web, and dividing the second web to form a plant growth medium. Said method. 2. The method of claim 1, wherein the compacting is performed using one or more substantially cylindrical rollers. 3. The method of claim 1, wherein the compacting is performed using one or more substantially conical rollers. 4. The compression at one end of the compression zone at a pressure of 0 to 400 kg / m and at the other end of the compression zone at a pressure of 100 to 2000 kg / m.
The method according to any one of claims 3 to 7. 5. The method according to claim 1, wherein the compression gradient generated in the compression zone has a linear profile. 6. The method according to claim 1, wherein the compression gradient generated in the compression zone has a non-linear profile. 7. The method according to claim 1, wherein the compression zone extends over only a transverse portion of the first web. 8. Compressing two or more discontinuous zones of the first web;
The method according to any one of claims 2 to 6, wherein the second web is divided into layers having planes parallel to the main surface of the web. 9. The method according to claim 1, wherein the entire first web is compressed using a single roller or a roller set. 10. A plant growth medium obtainable by the method according to any one of claims 1 to 9. 11. The plant growth medium according to claim 10, having an average density of ^{30 to} 120 kg / m ³ . 12. Use of the plant growth medium according to claim 10 for cultivating a plant. 13. An apparatus for producing a mineral fiber based plant growth medium having a density gradient, said means for providing a first web comprising a mineral fiber material and a binder, wherein the first web comprises at least one. Means for compressing in one longitudinal extension zone, compressing the first web such that the pressure increases substantially continuously in a direction transverse to the zone to create a compression gradient in that direction. Means for forming a second web, wherein the first web itself can be overlapped by laying the first web in a plurality of layers transversely of the second web; and The apparatus comprising means for splitting the web to form a plant growth medium.