New process technology with major environmental benefits

The energy required for space heating and domestic hot water accounts for a large share of total primary energy consumption – in Germany, for example, around 35%. This is a significant proportion, especially against the backdrop of the fact that the cost of primary energy is constantly rising in many countries and, due to scarce resources, this will not change. Since the availability of fossil energy sources is limited, it is becoming increasingly urgent to reduce primary energy consumption by improving the thermal insulation of buildings. Energy-efficiency standards are being discussed and implemented in many industrialized nations. Under the German Energy Saving Ordinance (EnEV) 2009, building law therefore stipulated that energy consumption for heating and domestic hot water must be reduced by 30%. This is to be achieved essentially by improving building insulation, which is to take effect both for new buildings and for modernization of existing buildings.

Implementation of EnEV 2009 is leading to increased demand for thermal insulation materials, from which manufacturers of wood fiber insulation boards also benefit. In terms of the overall insulation materials market in Germany, wood fiber insulation boards are certainly a niche product. In the 1960s and 1970s, they primarily secured their market position as a “green” product. Increasingly, however, technical advantages moved into focus, expressed in keywords such as “summer thermal protection,” “vapor-permeable construction,” and “sound insulation.”

The introduction of the environmental product declaration EPD (environmental product declaration) now offers the opportunity to bring the ecological aspect back to the fore: Taking into account thermal utilization at the end of the life cycle, wood fiber insulation boards are superior to mineral insulation materials because they can be incinerated. It does not take much imagination to foresee that, on the basis of the EPD, future restrictions can be expected regarding the maximum amount of non-renewable primary energy that may be incorporated into a building.

Capacity utilization in the wood fiber insulation board industry is correspondingly high, annual growth rates are in the double digits, and new investments are planned. Companies like SIEMPELKAMP, which present a convincing plant and process concept for insulation board production, are attracting the interest of producers worldwide. Companies such as Gutex in Germany or, currently, Mozyr DOK in Belarus are requesting the SIEMPELKAMP concept. As recently as fall 2010, the Belarusian company ordered a complete plant for the production of wood fiber insulation boards in Krefeld.

Innovative and energy-efficient: the SIEMPELKAMP ContiTherm® dry process

Several years ago, SIEMPELKAMP developed the dry process for the production of wood fiber insulation boards in order to avoid the disadvantages of the wet process that has been used in Europe since 1932: The entire water management of the wet process and the complex drying of the boards are eliminated. This made it possible to offer customers an attractive bundle of benefits – for example, reducing energy consumption by more than 30%, lowering board density, and producing homogeneous single-layer boards up to 240 mm thick.

What makes the SIEMPELKAMP dry process so unique? A key feature is the use of the continuous calibration and curing unit ContiTherm® to heat the prepressed fiber mat. Here, a steam-air mixture with an exactly controlled dew point is blown through the conventionally formed fiber mat. The steam component of the mixture condenses and heats the fibers to the dew-point temperature within a very short time – while maintaining the equilibrium moisture content required after the process.

A specially developed, highly reactive binder cures within a very short time after heating. This curing time is, incidentally, independent of board thickness – once heated, a 240 mm board sets just as quickly as a 20 mm board. This is a major advantage in the production of insulation materials, which are being installed in increasingly greater thicknesses. After calibration and curing, the board is cooled by drawing ambient air through it from top to bottom. The cured board then passes to the saw, is cut to size, optionally provided with tongue and groove, stacked, and packaged.

Thick fiber insulation boards in a continuous dry process: a first

As early as 2004, insulation board producer Gutex decided in favor of the first plant of the new type. The family-owned company based in Waldshut-Tiengen sets benchmarks in terms of innovative and environmentally friendly production technology.

The decision in favor of this plant was due not least to the fact that the new principle was demonstrated in the SIEMPELKAMP test center in the presence of the customer. On a 4’ (1,200 mm) pilot plant, Gutex was able to verify the feasibility of the newly developed dry process. The dry fiber gluing method was also put to the test here. A premiere aspect was that, after the dryer, the fibers are glued via ring spraying in the drop chute. The flow conditions in the drop chute prevent the glued fibers from sticking together. Calibration and curing of the formed mat in an adapted preheating unit are also regarded in the industry as an innovation.

After the test series in Krefeld, the breakthrough had been achieved and the gluing tower from the test hall could be integrated into the plant at the Gutex mill together with a second identical tower. For the Gutex team, working with the new technology was a welcome challenge: “In many cases we were breaking new ground – for example, in setting the fiber moisture, the dew point in the preheating unit, or the pressure settings. But of course our people understand the product very well, and cooperation with SIEMPELKAMP was and is very good,” summarizes Claudio Thoma, Managing Director of Gutex.

The plant went into operation in February 2006 and has been producing at full capacity ever since. “The plant delivers the agreed capacity; board thickness and strength are under control, and our customers rate the quality as very good. Overall, I can say that the process delivers what SIEMPELKAMP promised,” says Claudio Thoma. The bottom line: With this plant, SIEMPELKAMP has made the industrial production of thick fiber insulation boards in a continuous dry process possible and thus set a milestone in terms of board quality and process costs. Environmental friendliness is also fully taken into account: All wood fiber insulation boards produced by Gutex using the innovative dry process have met the strict requirements of natureplus© certification – the quality label for building products that are compatible with ecology, health, the environment, and function.

Flexible wood fiber insulation boards with bico fibers

In addition to rigid wood fiber insulation boards based on a PU binder, flexible boards are increasingly being offered that are used in particular for insulation between rafters in roof conversions and for insulation between timber studs. Their advantage is that they are sufficiently compliant to bridge typical construction tolerances. They also have sufficient clamping properties to prevent them from falling out during installation.

Flexible wood fiber insulation boards are produced without glue using two-component melt fibers – the so-called bico fibers. These consist of a high-melting core and a low-melting sheath. A mixture of wood fibers and bico fibers is formed and heated so that the sheath of the bico fibers melts and in this way forms the adhesive. The product is then cooled to fix the bonded state. In the finished board, a matrix of plastic fibers bonded to one another, or their high-melting cores, provides the required flexibility.

Conventionally, bico fibers with a sheath melting point of around 130 °C are used. The mat is heated by hot air (around 160 °C). As is well known, hot air is a relatively poor heat-transfer medium. The required air volumes are large – and so are the heat losses due to radiation, etc. When wood fibers are used, an additional complication is that they must first be dry before a temperature above 100 °C can be reached.

Faster and more energy-efficient thanks to bico fiber plus ContiTherm®

To meet this challenge, SIEMPELKAMP has taken the dry process one step further. Together with EMS-Chemie AG in Switzerland, the company developed a bico fiber that already melts under the conditions of the ContiTherm® process – that is, at below 100 °C! The advantage is that the mat is now heated significantly faster and therefore more energy efficiently than with hot air, and the wood fibers are not dried in the process. Another side effect: The required cooling – for this, ambient air is drawn through the board – is significantly faster because at least part of the water condensed during heating evaporates again and in this way contributes substantially to cooling.

For applying the bico fibers, SIEMPELKAMP has developed a process that mixes these fibers extremely homogeneously with the wood fibers. The quantity of special fiber used can therefore be significantly reduced compared with the proportions otherwise customary. This development, too, was successfully put to the test on the 4’ (1,200 mm) pilot plant in the SIEMPELKAMP test center.

From rigid to flexible: insulation board plant for Mozyr DOK

The special highlight of a currently ordered SIEMPELKAMP insulation board plant is its variability: The plant ordered by Mozyr DOK in Belarus is designed for the production of both rigid, PU-bonded boards and flexible boards with bico fibers. In both variants, a wide range of board thicknesses, densities, and formats can be produced.

A complete plant is being supplied, including an energy plant for dryer heating and process steam supply. The scope of supply includes the complete front-end know-how from Krefeld – for example, debarking and chip production, silo/bunker with discharge device and conveyors. Refiners, fiber dryer, dry gluing, forming line with ContiTherm®, and finishing line with profiling and stacking/packaging (from Wolfratshausen) are also part of the order volume. Engineering is being handled by Sicoplan, and this type of plant is also being planned entirely in 3D (see illustration).

The maximum raw board width is 2,620 mm, so that all common board formats can be produced with optimized trimming. A width-adjustment feature in the ContiTherm® also contributes to this. Mozyr DOK, a producer of doors, flooring, and furniture, will process softwoods such as spruce and pine with the new plant. Commissioning of this insulation board plant with a fiber throughput of 7 t/h – annual capacity of 380,000 m3 at average raw density – is scheduled for spring 2012.

Wood fiber insulation boards: benefits for producers and customers
- Energy-efficient production
- Green product made from renewable raw materials
- CO2 storage capability
- Medium term: significant benefits from environmental product declaration (EPD)
- Wide range of applications:
 - Wall cladding
 - Roof insulation
 - Impact sound insulation
- Many application-related advantages:
 - Summer thermal protection
 - Good thermal and sound insulation
 - Insensitivity to moisture
 - Vapor-permeable construction without vapor barrier
- Unproblematic disposal (thermal utilization)
- Low proportion of additives in the dry process