EP2036692A1 - Method for producing dampening and/or noise insulation boards from wood fibres in a dry process and a calibration and hardening device - Google Patents

Abstract

The method involves elevating a surface layer seal in comparison to a middle layer for group of reactive isocyanate binding agents, particularly polymeric diphenylmethane diisocyanate. A surface side of a mat (7) in a sizing and hardening unit (8) is heated above ninety five degree Celsius, particularly one hundred twenty degree Celsius for forming a surface layer (9). A steam or steam-air-mixture is induced into the entire mat after the compression of a product thickness. A binding agent is completely hardened, where the product thickness is kept constant. An independent claim is included for a sizing and hardening unit for use in a sound insulating and damping plate manufacturing system.

Description

The invention relates to a method for producing insulating and / or soundproofing of wood fibers in the dry process without active post-drying according to the preamble of claim 1 and a calibration and curing device for the production of insulating and / or soundproofing panels according to the preamble of claim. 7

With the increasing demand for heat insulation materials for the production of energy-saving houses (Heat Protection Ordinance from 1982 and the subsequent tightening of the same, including the newly introduced after the turn of the millennium energy pass for houses) has in the last 30 years in the insulation again a biodegradable and renewable Raw material brought into the conversation, the wood fiber. In recent years, due to the relevance of climate change, the thermal insulation based on wood fiber has regained a market and there is a great need for innovation Manufacture wood fiber insulation economically. Wood fiber insulating materials are currently available on the market in loose form, whereby the wood fibers are blown into prepared cavities and in this case form the insulating layer or in solid form as Holzfaserdämmplatten.

Since the global increase in crude oil and energy prices, efforts are being made not only to carry out house insulation on oil-based insulating materials, but also to save as much energy as possible in the manufacture of insulating materials and to be independent of oil-based insulating materials. At the same time, the insulation materials produced for the wall insulation should be easy to process, have sufficient strength during transport or handling against breakage or cracks and at the same time emit no organically harmful pollutants. In addition, the existing rigid foam products or mineral wool used could not guarantee the optimal living climate within a building in addition to the ecological problems. So far, the reasons for building owners have been combated in an environmentally non-ecological way because of the high energy consumption of wood fiber insulating materials.

Previously known and common methods are the wet process and the dry process. Basically, the raw material is processed from logs or sawmill residues to wood chips, under pressure and Heat cooked and shredded by means of a refining device (Refiner). In the wet production of wood fiber insulation boards, the suspension is spread from the refiner to a wet soft fiber mat and usually calibrated and pressed by calender. Subsequently, the drying and the associated hardening take place via a hydraulic cycle press. In addition to insufficient dimensional stability, the poor environmental compatibility and the enormous energy consumption are disadvantageous.
In the dry production of Holzfaserdämmplatten the emerging from the fiberizer (refiner) fibers are dried and formed after the addition of binders dry to a mat. Calibration, drying and curing are then carried out in a throughflow dryer in which hot air flows through the wood fiber insulation board ( EP 0 330 671 B1 ).
The simplification of the plant components and the advantage of being able to produce considerably thicker insulating boards with independent strength have made the process widely used despite the enormous energy costs for drying.

In the article " Holzfaserdämmstoff nach der Super-Trockenverfahren "by Hans Korte, Wismar, published in the wood-Zentralblatt number 110, page 1300, issue of 13 September 2002 , the development of previous dry processes is described to a super-dry process. It is the Procedure as follows: After defibration, the wet fibers are dried in a tube dryer to a final moisture content of about 6% and then mixed with an anhydrous binder (PMDI). Subsequently, the fibers are scattered to a mat and compacted after forming in a calibration and curing unit to product thickness and cured. The curing takes place by the introduction of a vapor-air mixture, which condenses in the previously dry fiber mat. Due to the rapid introduction of moisture and heat, the binder can set quickly and after a short distance, the product leaves the calibration and curing unit with a moisture content of about 12%. The advantage of this method over the prior art is the formaldehyde-free production, the low energy consumption by no longer necessary drying and the possible production of low density wood fiber insulation panels with only one layer. Also the DE 102 42 770 A1 is the subject of this procedure.

The object of the present invention is to provide a method by which insulating and / or soundproofing mat or panels can be produced which have an increased density on at least one surface side in order to increase the handling and the usability of the end product. At the same time, the advantages of the simplified process sequence of the dry process known from the prior art can be used without the necessity for subsequent drying with the associated simple system construction as part of the production. Next is a calibration and Hardening be created in a plant for the production of insulation and / or sound insulation panels, which makes it possible to heat at least one cover layer before or during the compaction of the scattered mat.

The solution to this problem for a method is that at least one surface side in the calibrating and curing unit is heated above 95.degree. C., preferably 120.degree. C., to form cover layers, with the mat simultaneously and / or subsequently being used in the calibration and curing unit is compacted and wherein after the compressing to the product thickness of steam or a water vapor-air mixture is introduced into the entire mat and the adhesive is fully cured while the product thickness is kept constant.

The solution for a calibration and curing unit is that at least one heating device is provided in the calibration and curing unit in the production direction in front of the sputtering apparatus for at least one cover layer of the mat.

With the proposed method, it is now possible to produce insulation and / or soundproofing mat or panels ecologically and economically with the advantages of simple super-dry process without post-drying and at the same time arises by heating the cover layers to above 95 ° C before or during the calibration compaction on product thickness one Cover layer with an increased density. This is possible because, according to the teachings of the invention, the cover layers are already softer before or during compaction and thus can be compressed better during compaction than the other layers not yet heated.

This compaction, carried out according to the teaching, effectively leads to higher densities in the outer layers of the later insulating or soundproofing plate. The lowest compression resistance of wood fibers is at temperatures greater than or equal to 120 ° at about 6-8% humidity. By the method according to the invention, the wood softening point is achieved in the outer layers, wherein in the middle layers continue to temperatures far below 100 ° C are present. This temperature difference is adjusted by the proposed heating methods of the cover layers. In a preferred embodiment, the mat lingers in the softening zone for 10 to 100 seconds, preferably 20 seconds. The dwell time can be set not only individually on the production speed but also on the touch point of the mat with the mesh belt in the softening zone. By moving the contact point of the mat with the mesh belt in the softening zone in the direction of production, the residence time in the softening zone decreases at the same feed rate.

In a preferred embodiment, at least one cover layer can be sprayed with water before the calibration and curing unit and / or the Overcoat moisture can be adjusted higher by sprinkling two or more layers of the mat, spreading the corresponding layer with a higher moisture content. This higher scattered light can be adjusted by removing fiber material in the drying area in advance and not yet achieving the necessary degree of drying of the fibers necessary for the middle layer. However, it can also be provided for the respective layer an additional scattering station and the fibers can be equipped, for example, after a split on the transport to the scattering station, in the scattering bin or even in the scattering head itself with a higher humidity.

The necessary for the process, but also used alone for the process in a manufacturing plant calibration and curing unit consists of at least one revolving upper screen belt and a lower, the mat-bearing, screen belt. The upper rotating belt is guided by means of several rollers depending on the setting. In this case, it is particularly advantageous to carry out the mesh belt as a metal mesh belt. The steam plates required at the end of the calibration and curing unit consist of hardened steel in order to minimize the abrasion caused by the passing metal mesh belt as much as possible.

In a preferred embodiment of the calibration and curing unit, it has been found that it is advantageous for the upper and / or the lower screen belt to run as two consecutively arranged screen belts. In the area of cover layer heating and compression, in this case, a metal mesh belt is used, which is driven by a large heated driven drive drum on the inlet side. As part of the compaction, the metal fabric belt runs past roller rolls, wherein heating plates are arranged in each case in parallel between the roller rollers. These hot plates can be heated, for example, with steam or thermal oil and give their heat energy to the outer layers and the metal mesh tape. The metal mesh tape is preferably made of steel or bronze and has good heat conduction to the cover layers. Due to the division of the upper circumferential sieve cloth belt, it is now possible to manufacture and use the second circulating wire cloth belt made of plastic. Since the plastic no longer plays a role for the heat transfer (the transfer is carried out by the steam or vapor-air mixture flowing into the mat) also less friction on the steam plates and thus increases the life of a rotating screen fabric belt made of plastic and the life the steam plates significantly. In a two-part upper screen belt in the calibration and curing unit, a small gap is created between the two circulating screen belts, which are guided on deflection drums. Advantageously, the cover layers no longer tend to spring open very much and it should not be necessary to take special measures for keeping the mat down. However, in order to minimize this gap between the screen belts, The second rear mesh belt made of plastic at a lug (very small Umlenkrollendurchmesser) are deflected. For a metal mesh tape, this would not be possible in this form.

• Demnach werden Hackschnitzel oder dgl. im Trockenverfahren in einem Refiner gemahlen, die aus dem Refiner austretenden feuchten Fasern werden auf eine Feuchte von 4% bis 8% atro Holz getrocknet, vorzugsweise mit einem Trommeltrockner und mit einem wasserfreien Bindemittel in einem Mischer oder während dem Durchlauf durch eine pneumatische Förderlinie vermischt. Anschließend werden die trockenen Fasern zusammen mit dem Bindemittel auf einem Formband zu einer Matte gestreut. Je nach Anlagenform wird die Matte an eine Kalibrier- und Aushärteinheit übergeben und dort auf die gewünschte Produktdicke mit einer Rohdichte von 40 - 200 kg/m³ verdichtet und ausgehärtet. Dabei wird in die verdichtete Matte ein Dampf oder ein Dampf/Luft-Gemisch eingeführt, das noch während des Durchlaufes durch die Kalibrier- und Aushärteeinheit für ein vollständiges Aushärten der Matte zu einem verarbeitbaren Endprodukt führt, wobei die Ausgleichsfeuchte in etwa 12% beträgt. Das verwendete wasserfreie Bindemittel, vorzugsweise PMDI, wird ab einer Temperatur von 90° C aushärten. Der Vorteil durch die extreme trockene Herstellung besteht darin, dass die Feuchte am Endprodukt nicht mehr entfernt werden muss und teure Energie- und Anlagekosten für diese bisher übliche Trocknung entfallen.

In a particularly preferred embodiment, according to the method according to the invention, the necessary parameters and method steps from the prior art are adopted and modified with the teaching of the invention:

• Accordingly, chips or the like are ground in a dry process in a refiner, the wet fibers emerging from the refiner are dried to a moisture of 4% to 8% dry wood, preferably with a tumble dryer and with an anhydrous binder in a mixer or during the run mixed by a pneumatic conveyor line. Subsequently, the dry fibers are scattered together with the binder on a forming belt to a mat. Depending on the system shape, the mat is transferred to a calibration and curing unit where it is compacted and cured to the desired product thickness with a bulk density of 40 - 200 kg / m ³ . In this case, in the compressed mat, a steam or a vapor / air mixture is introduced, which still leads during the passage through the calibration and curing unit for complete curing of the mat to a workable end product, wherein the equilibrium moisture content is about 12%. The anhydrous binder used, preferably PMDI, will cure from a temperature of 90 ° C. The advantage of the extreme Dry production is that the moisture on the final product no longer needs to be removed and expensive energy and investment costs for this previously customary drying accounts.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the dependent claims and the following description with the drawing.

Figur 1

Eine schematisch dargestellte Herstellungsanlage von Dämm- oder Schallschutzplatten aus Holzfasern im Trockenverfahren ohne aktive Nachtrocknung,

Figur 2

die Kalibrier- und Aushärteeinheit nach Figur 1 mit einem oben umlaufenden Siebgewebeband und

Figur 3

die Kalibrier- und Aushärteinheit nach Figur 1 mit zwei oben umlaufenden Siebgewebebändern für den Erweichungsbereich der Deckschichten und den Aushärtebereich.

Show it:

FIG. 1

A schematically illustrated production plant of insulating or soundproofing panels made of wood fibers in a dry process without active post-drying,

FIG. 2

the calibration and curing unit after FIG. 1 with a top-rotating mesh belt and

FIG. 3

the calibration and curing unit after FIG. 1 with two top strainer belts for the softening of the top layers and the curing area.

As in FIG. 1 The insulating or soundproofing panels 12 are produced from a raw material 1 which is ground as dry as possible in a shredding apparatus 2 and defibered. In a drying device 3, here shown as a tube dryer, the wet fiberized raw material 1 is dried to about 4% to 8% and finally glued in a gluing station 4 with adhesive. The mixing with an adhesive as a binder can on take different ways. Incidentally, as the adhesive used here, the adhesive is cured by the treatment in the process. When using PMDI as an adhesive / binder, it makes sense to spray this in a pneumatic conveyor line on the fiber material or even to mix in a suitable mixer. Subsequently, the fibers are scattered in a scattering device 5 on a forming belt 6 to a mat 7 and spent for calibration and curing unit 8. The calibration and curing unit 8 is subdivided into two areas according to the teaching of the invention, wherein in the production direction 22 first the softening area 9 is arranged for the cover layers and then the curing area 10.

In a further embodiment, the calibration and curing unit 8 can also be divided into three areas (not shown). In such a division, only a slight or no densification would take place in the softening area, while the cover layers are softened with the increase in temperature. For a device that meets all requirements, it would be useful in this case to arrange a joint in the softening region 9, at which different compaction angles (two-stage compaction) can be set. Applicable for all areas to be adjusted is that hydraulic or pneumatic actuators are provided which are capable of setting the necessary compaction angles.

After leaving the calibrating and curing unit 8, the endless strand is divided into insulating or soundproofing plates in a dividing device 11, preferably a diagonal saw with moving transverse saws or a rotary clipper. In the field of insulation, the transition from relatively stiff plates to relatively flexible mats is fluid. It is understandable that in this case also deformable insulation material can be produced. The denser top layers facilitate handling during manual transport or when processing the insulation or soundproofing mats.

In FIG. 2 Now, a first embodiment of a calibration and curing unit 8 is shown. The peculiarity relates to the use of only one upper mesh belt 19 in the entire calibration and curing unit 8. The lower mesh belt can be made either by the forming belt 6 or in the calibration and curing unit 8 own Siebgewebeband 25 is arranged. It is the teaching of the invention after irrelevant whether Siebgewebebänder or pure screen belts are used. The circulating Siebgewebebändern are basically performed by means of several rollers 14 and pulleys 13 and 16 depending on the setting. In this case, it is particularly advantageous to carry the Siebgewebebändern 19 and 25 as a metal mesh belt. The necessary at the end of the calibration and curing unit 8 steam plates 18 in Curing area 10 consist of hardened steel in order to minimize the abrasion caused by the passing metal fabric belt as possible. In the softening region 9 for the cover layers, a heating device 26 is arranged. This is after FIG. 2 an arranged between the pressure rollers 14 RF heater 24. This is shown lined on the lower mesh belt 25 only lined as an option. In an advantageous manner, a joint can also be arranged between the heating area 9 and the curing area 10 in order to better adjust the different angular positions of the individual areas relative to one another.

In a second embodiment according to FIG. 3 the upper mesh belt is advantageously divided into two parts. This can also apply to the lower mesh belt, depending on the application. In the softening region 9 and the compaction carried out here at the same time (this can also be carried out after appropriate preheating, as required), a metal fabric belt 20 is used here, which is driven by a large heated driven drive drum 13 on the inlet side. The metal fabric belt 20 passes in the context of compaction past pressure rollers 14, wherein in each case 14 parallel heating plates 15 are arranged between the pressure rollers. These heating plates 15 can be heated, for example, with steam or thermal oil and release their heat energy to the cover layers directly and via the metal fabric belt 20. The metal fabric tape 20 is preferably made of steel or bronze and has a good heat conduction to the outer layers of the mat 7. Due to the division of the upper circumferential sieve cloth belt, it is now possible to carry out the second circulating sieve cloth belt as a plastic cloth belt 21. This is possible because the plastic fabric tape 21 in the curing area 10 plays no role in the heat transfer, since the heat is introduced into the mat 7 through the vapor-air mixture. As a result, the service life of a circulating mesh fabric belt made of plastic increases significantly and the steam plates of the steamer 27 need not be made hardened. In a two-part upper Siebgewebeband in the calibration and curing unit creates a small gap between the front circumferential metal fabric belt 20 and the subsequent encircling plastic fabric belt 21, since both have to be guided over idler pulleys 16/17. Advantageously, the cover layers no longer tend to spring open and it should not be necessary to take special measures for keeping the mat down. In order nevertheless to keep this gap 28 between the Siebgewebebändern as low as possible, the plastic fabric belt 21 can be deflected at a very small tail pulley 17 (diameter about 20 mm). Depending on the design of the calibrating and curing unit 8, it is initially impossible or only slightly compacted in the softening area 9. The compaction can be variably adjusted, in which the softening area has corresponding lifting devices which can set the compaction angle and the height of the mat 7.

Basically, it may be useful to spray the Siebgewebebänder or metal fabric tapes in the return with a release agent by a release agent application unit 29 or to wet with a suitable contact device (roller) and / or provide a cleaning device 30. In principle, the use of release agent is also a spraying on the forming belt 6 before scattering of the fibers and / or wetting of the surfaces of the mat 7 before entering the calibration and curing unit. 8

List of Reference Numerals: DP 1346 EP

1.

raw material

Second

Fiberizer (Refiner)

Third

drying device

4th

gluing station

5th

spreader

6th

forming belt

7th

mat

8th.

Calibration and curing unit

9th

Softening surface layers

10th

curing area

11th

partitioner

12th

Insulation or sound insulation board

13th

Umlenktrommel

14th

platen

15th

Hot Plates

16th

Umlenktrommel

17th

Umlenktrommel

18th

steam plates

19th

Siebgewebeband

20th

Metal fabric tape

21st

Plastic cloth tape

22nd

production direction

23rd

product thickness

24th

RF heating

25th

Siebgewebeband

26th

heater

27th

A steamer

28th

gap

29th

Release agent application unit

30th

cleaning device

31st

humidifying

Claims (11)

Process for the preparation of insulating and / or soundproofing of wood fibers in the dry process without active post-drying with at least one compared to the middle layer increased cover layer density, which are digested from wood chips or similar material in a refiner, then the wood fibers are dried to less than 10% atro wood and simultaneously or subsequently with an anhydrous, belonging to the group of reactive isocyanates binder, preferably PMDI, glued and sprinkled after gluing with a fiber spreading machine on a forming belt and formed into a mat, said mat then in a continuously operating calibration and curing unit compressed and treated with steam and / or a vapor-air mixture and cured, characterized in that at least one surface side of the mat in the calibration and curing unit to form a cover layer to above 95 ° C, preferably 120 ° C, is heated,
wherein simultaneously and / or subsequently the mat is compacted in the calibrating and curing unit, and
wherein, after compacting to the product thickness, steam or a water vapor-air mixture is introduced into the entire mat and the binder is fully cured while the product thickness is kept constant. A method according to claim 1, characterized in that one or both surface sides of the scattered mat are subjected to water before entering the continuously operating calibration and curing unit. A method according to claim 1, characterized in that upon application of water to one or both surface sides of the mat 10 to 400 g / m ^{2 of} water are used. Method according to one or more of the preceding claims, characterized in that during or before the compression in the curing unit steam or a vapor-air mixture is introduced into at least one cover layer. Method according to one or more of the preceding claims, characterized in that preferably mats for a Product density of less than 100 kg / m ^{3 are} manufactured. Method according to one or more of the preceding claims, characterized in that at least one two-layer mat is formed, wherein at least one cover layer either an increased moisture content and / or finer fibers having a higher bulk density, which in the compression compared to the middle layer less compression resistance brings to. Method according to one or more of the preceding claims, characterized in that the mat and / or the screen belts are subjected to release agent. Calibration and curing unit in a plant for the production of insulating and / or soundproofing of wood fibers in a dry process without active post-drying, consisting of a refiner, a dryer, a gluing station, a fiber spreading machine with arranged underneath forming belt and a finishing in the direction of production calibration and curing unit,
characterized,
in that in the calibration and curing unit (8) in the production direction (22) in front of the curing area (10) for at least one cover layer of the mat (7) at least one heating device (26) is provided. Calibration and curing unit according to claim 8, characterized in that as heating devices (26) in the calibration and curing unit (8) heating plates (15) or HF heaters (24) are arranged. Calibration and curing unit according to claim 8, characterized in that for the moistening of at least one cover layer on the scattered mat (7) at least one moistening device (31) is arranged prior to entry into the continuously operating calibration and curing unit (8). Calibration and curing unit according to claim 8, characterized in that in the return of the Siebgewebebänder a cleaning device (30) is arranged.

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