DE102019107982A1 - Flame, fire and glow-protected natural fiber insulation materials and their production and use, in particular for natural fiber insulation products - Google Patents

Abstract

The invention relates to novel flame, fire and glow-protected natural fiber insulation materials and their production and use, in particular for natural fiber insulation products, in particular we insulation fiber boards, nonwovens, blown insulation materials. The natural vegetable fibers are essentially hemp fibers, possibly containing conventional insulation additives, i.e. they essentially consist or comprise hemp fibers and, if necessary, the usual insulation additives.

Description

The invention relates to novel flame, fire and glow-protected natural fiber insulation materials and their production and use, in particular for natural fiber insulation products, in particular we insulation fiber boards, nonwovens, blown insulation materials.

Means, in particular a flame retardant and / or fire retardant, to reduce the flammability and / or combustibility of various materials or substances, such as wood and wood products, textiles and textile products, paper and paper products, cardboard, fibers and fabrics, paints, etc., or based on or in combination with polyolefin-based materials and / or products and / or intermediate products, including composite materials and / or composite materials therewith, the production of the agent and methods or processes using the agent and / or the corresponding combination of its individual components for reduction the flammability and / or combustibility are already known in the more recent state of the art, for example from patent publications WO 2017/081240 A1 and WO 2017/118765 A1 .

For easily inflammable materials and substances, it is important to provide them with flame and / or fire protection that makes such materials and substances less dangerous. In the case of fibrous materials and substances, in addition to the flame and / or fire protection problem, which can be solved by flame retardants and / or fire retardants, another serious problem arises which, despite the added flame retardants and / or fire retardants, easily turns into a self-evident even after a long time The re-kindling of already extinguished, even originally small ones that have already been extinguished, can lead to fires and sources of fire with devastating consequences.

Compared to lumpy and / or compact materials and substances, fibrous materials and substances have a fairly high surface area and good air retention capacity, so that in the event of an undetected glow or afterglow of such fibrous materials and substances, e.g. In the event of a fire or a fire that was believed to have been extinguished, the embers of the glowing areas, possibly hidden, act as sources of ignition and propagation for a fire that is emerging or not completely extinguished. In this case, the embers, possibly hidden, can initially spread in a fatal manner into fibrous materials and substances, whereby these initially receive sufficient oxygen nourishment through air inclusions, and then through from the outside through e.g. Wind, ventilation, etc., new air entering the fire can be ignited or re-ignited.

This is all the more problematic because fibrous materials and substances are nowadays increasingly being used for thermal and / or sound insulation, in particular to replace the polystyrene insulation, which is currently considered to be particularly problematic in terms of fire, with materials and substances that also have favorable insulation properties, but also in offer advantages in terms of fire technology that allow classification as B1 (flame-retardant), i.e. flame-retardant building materials (see, for example, the assignment of building material classes according to DIN 4102-1 tests or according to the European classification according to EN 13501-1). Most of the thermal insulation and / or sound insulation available today on an organic basis are only classified according to B2 (normally flammable).

There are already wood fiber insulation materials that have B1 classification, but which do not meet the required glow behavior or non-glow behavior, which is necessary for the use of the insulating materials in building classes 4 and 5, and therefore not for use in building classes 4 and 5 are permissible. Smoldering behavior occurs when the flame continues for longer. A lot of energy is generated here, the fiber insulation, for example fiber insulation boards, start to glow and the glow does not stop, and thus ultimately ensures the complete destruction of this insulation. To determine the glow behavior of the insulation, e.g. of insulation boards, to be determined in the glow test, the insulation, e.g. the insulation boards are permanently exposed to a flame for 10 minutes in the fire shaft. A lot of energy is generated here; after the 10-minute flame has been set, the panels will continue to glow until they are completely destroyed.

The invention relates to a means and method for reducing the flammability and / or combustibility of fibrous materials and substances based on natural substances, in particular containing flame retardants and / or fire retardants, which also offer effective corona protection, i.e. to which an effective corona protection agent is additionally added in sufficient quantity is. In addition, the means of the invention should also provide good protection against an initial glow, possibly spreading glow, and after-glow, even in the case of insulating materials based on natural fibers which may still contain synthetic fiber components.

Mixtures of organic and / or inorganic substances are known as common flame retardants and fire retardants, which are intended to ignite or just ignite wood or wood-like materials, plastics, textiles, paper, cardboard, cardboard, synthetic and natural fibers as well as fabrics, paints, or products made from them, building materials, insulating materials, electrical and / or to prevent or at least inhibit cable insulation etc. In addition, they should, in particular, make it more difficult to burn these substances and thus prevent fires, at least for a sufficient period of time.

In the field of natural fiber-based insulating materials and substances, flame protection and / or fire protection is still not satisfactorily solved in practice, despite various proposals in the prior art. In particular for products made of fibrous materials and substances, e.g. by foaming, felting, "loose" air-entrapping compression and / or pressing / pressing (fibreboard), or based on such fibrous materials and substances in combination with synthetic fiber-based materials and / or products and / or preliminary products, is flame protection and / or fire protection continues to be unsatisfactory, since unfortunately, even after treatment with inorganic and / or organic flame retardants and / or fire retardants in the flame retardant and / or fire protection test, they can still show a non-negligible glow and afterglow. In particular after further processing with the inclusion of air and the addition of other substances such as Glues or adhesives to form air-enclosing foamed, felted or air-enclosing compressed or air-enclosing compressed / pressed insulation products, despite improved flame protection or fire protection behavior, unexpected afterglow occurs, in the worst case even up to the decomposition of the insulation material mentioned Products on. This unwanted afterglow was still not satisfactorily solved in practice by products and / or preliminary products for insulation, both indoors and outdoors, despite various proposals in the prior art.

Against this background, the object of the invention is to provide a means and method for corona protection, including afterglow protection, which does not damage the material, product and / or intermediate product to be protected and in particular does not release toxic gases and the desired material properties with regard to the Do not impair the insulation, or at least only insignificantly. The production of the means and their use should be simple and economically very favorable for the natural fiber-based materials and fabrics and / or products and / or preliminary products for insulation, both indoors and outdoors.

This object is achieved with the features of claim 1. The subclaims refer to advantageous configurations. This object is achieved in particular with such a use and such a means and such a method, having the features as specified in the claims.

Accordingly, the invention relates in the broadest sense to the use of expandable graphite, in combination with at least one agent for reducing flammability and / or combustibility, in particular the use as a corona protection agent and / or afterglow protection agent, which causes a glow and / or afterglow in natural fiber-based materials and Substances and / or products and / or preliminary products for insulation which consist of or comprise natural fibers and / or natural fiber-based materials and substances containing synthetic fibers. In particular, the invention relates to these natural fiber-containing materials and substances and / or products and / or preliminary products for the insulation of walls, floors and / or ceilings of buildings; Building parts and / or also for the system and / or container / container insulation. Such materials and substances and / or products and / or preliminary products for insulation can be provided according to the invention for both indoor and outdoor areas.

Insofar as the invention is described below using the example of hemp fibers and materials produced therefrom or comprising them and / or (pre-) products for insulation, the person skilled in the art will recognize that this disclosure also applies to other natural fibers and materials made from them or comprising them / or (pre) products for insulation apply.

The invention relates in particular to an agent containing expandable graphite for reducing the flammability and / or combustibility and especially the smoldering and / or afterglowing of fibrous materials and substances and / or products and / or preliminary products for insulation.

Preference is given to products and / or pre-products insulating building material products, for example in the form of foam, pressed, felt, fleece and / or composite (pre-) products, consisting of or comprising natural fibers, possibly with customary additives as well common binders. Such products can be fiberboard or fiber felts or nonwovens, e.g. in the form of mats or wool, or blown foams or blown felts (so-called blown insulation materials), and these products are for insulating construction purposes, for example for indoor and / or outdoor use, in particular for insulating walls, floors and / or ceilings Buildings; Parts of the building and / or also for the system and / or container / container insulation, suitable and / or set up for this, or can be used for this.

The invention also relates to those fibrous materials and substances and / or (pre-) products which consist of or include other conventional additives and natural fibers and / or natural fibers containing synthetic fibers, where appropriate, in these fibrous materials and substances and / or (pre-) products to reduce flammability and / or combustibility, and in particular as corona protection agents and / or afterglow protection agents, expandable graphite is incorporated.

In view of the steadily rising energy prices, the subject of thermal insulation is more topical than ever. When choosing the right thermal insulation, natural insulation materials are playing an increasingly important role. This is because these are permeable to water vapor and thus have clear advantages over conventional thermal insulation materials.

According to the invention, the term “fiber” is understood to mean: A fiber is a structure that is thin and flexible in relation to its length and consists of a fibrous material. To speak of a fiber in the technical field, the ratio of length to diameter should be at least between 3: 1 and 10: 1; for many, e.g. textile, applications it is over 1000: 1. Fibers cannot absorb compressive forces in the longitudinal direction, only tensile forces, as they buckle when subjected to pressure. A fiber in the sense of the present invention is thus a linear, elementary structure which consists of a fiber material and an outer fiber shape, i.e. has a simple, curled longitudinal shape and an approximately round, angular or similar cross-sectional shape. The fiber can be endless or of limited length and is a thin, flexible structure in relation to its length. In nature and in technology, fibers usually occur in a larger composite, which accordingly also applies to the present invention.

Natural fibers are divided into organic fibers with the subgroups vegetable and animal fibers as well as mineral (inorganic) fibers. In the context of the present invention, natural vegetable fibers are preferred. Natural fibers in the context of the present invention are all textile fibers and fiber materials that are obtained from plants without chemical modification. The present invention specifically does not relate to mineral fibers, i. no inorganic fibers.

Basically, different forms of natural fibers can be distinguished: Wood fibers consist of elongated wood cells, whereby wood fibers contain around one fifth of lignin and four fifths of cellulose, depending on the type of wood. Bast fibers consist of multicellular fiber bundles. They are elongated and thick-walled cells that are not lignified. The main component of bast fibers are essentially layers of elongated cellulose fibrils of different thicknesses, which are enclosed by hemi-cellulose. Typical natural fibers based on bast fibers are, for example, hemp fibers. Natural fibers from green cuttings, in particular from grass cuttings or rye cuttings, consist primarily of hard fibers, which are also essentially based on cellulose. Hard fibers usually have a higher hardness than bast fibers, but the hard fibers are more sensitive to bending stress.

Vegetable fibers (plant fibers), which are suitable according to the invention as natural fibers, occur in plants as vascular bundles in the stalk or trunk, the bark, for example as bast and as seed extensions. The “fibrous” property is unspecifically defined as the “lignified” parts of an herbaceous plant, which are strongly interspersed with fibers, in distinction to the young shoots and the leaf mass.

• Samenfasern weisen eine einzellige Struktur auf, die von den Epidermiszellen des Samen gebildet wird. Sie setzen sich fast ausschließlich aus Cellulose zusammen, beispielsweise: Baumwollfaser (CO) aus den Samenhaaren der Frucht der Baumwollpflanze; Kapok (KP) aus dem Inneren der Kapselfrucht des echten Kapokbaumes; Akon aus Seidenpflanzengewächsen; Pappelflaum.

The term "plant fiber" is a collective term for fibers of plant origin that are used as material, for example in textile and other manufacturing processes. A subdivision takes place, for example, according to DIN 60001-1 in seed fibers, bast fibers and hard fibers or according to the international standards DIN EN ISO 6938 into seed fibers, bast fibers, leaf fibers and fruit fibers, which divide the hard fibers. The following list, which, if available, also contains the valid abbreviations for the fiber generic names, is mainly based on these two standards:

• Seed fibers have a unicellular structure formed by the epidermal cells of the seed. They are composed almost exclusively of cellulose, for example: Cotton fiber (CO) from the seed hairs of the fruit of the cotton plant; Kapok (KP) from the inside of the capsule fruit of the real kapok tree; Akon from silk plants; Poplar fluff.

Bast fibers, which are preferred according to the invention, are composite fibers that are obtained from the bast of certain plants, mostly from cellulose, but also accompanied by pectin bodies, hemicellulose and possibly lignin; Examples include: bamboo fiber made from (Bambusa textilis); Greater nettle fiber nettle; Hemp fiber (HA), which is particularly preferred according to the invention; Siberian hemp nettle; Jute (JU); Urena (JR) from mallow family; Flax fiber, also called linen (LI); Ramie fiber (RA) from the tropical nettle species ramie; Kenaf fiber (KE) from Kenaf (Ostinischer hemp marshmallow); Roselle (JS) fibers (Sudan Marshmallow); Fibers of the Sun (SN) (Crotalaria juncea); Abutilon from the beautiful mallow; Punga from (Clappertonia ficifolia); Castor oil from the wonder tree (Ricinus communis); Bluish Dogbane from the hemp-like dog strangler (Apocynum cannabinum).

Leaf fibers are composite fibers obtained from leaves and are composed mainly of cellulose, as well as encrusting and intercellular materials composed of lignin and hemicelluloses; Examples are: Sisal (SI) made from agave leaves; Abacä (Manila hemp) (AB), leaf fiber from the leaves of the banana species [Musa textilis]; Curauä from bromeliads; Agave fiber; Ixtle fiber, also tampico fiber from agave lechuguilla; Arenga fibers from the leaf sheaths of the sugar palm; Afrik or palm fiber from a dwarf palm; Henequen fibers (HE) from the Agave fourcroydes; Fique (FI) leaf fibers from Furcraea macrophylla; Phormium, also New Zealand flax (NF) from Phormium tenax; Alfa (AL) from the leaves of the alfa grass; Maguey from the leaves of the agave cantala; Yucca made from the leaves of the palm lily family Yucca carnerosana; Pita from the leaves of Aechmea magdalenae.

Fruit fibers are composite fibers obtained from fruits and composed mainly of cellulose, as well as encrusting and intercellular materials composed of lignin and hemicelluloses; An example is: Coconut fiber (CC) from the shell of the coconut palm fruits.

Alternatively or in addition to the aforementioned types of fibers, e.g. so-called substitute fibers can also be used, for example: gorse: fibers from the stems of the gorse plant with a fiber yield of 6% to 7%; Hops: fibers from the stems of hop plants with a fiber yield of 9% to 10%; Cattail reeds: fibers from the leaves and from the fruit stands with a fiber yield of 25 to 30%; Willow bast: bark fibers of the willow with a fiber yield of 15% to 20%.

• - Cellulose Dämmung: Celluloseflocken überzeugen durch ihr sehr gutes Preis-Leistungs-Verhältnis.
• - Jutedämmung: Aus alten Jute-Transportsäcken wird durch Upcycling ein wohngesunder Baustoff mit guten Dämmeigenschaften.
• - Flachs-Dämmung: Flachs ist eine der ältesten Kulturpflanzen und wurde bereits in der Steinzeit verwendet. Nun wird Flachs als Dämmstoff neu entdeckt.
• - Hanf-Dämmung: Die Kulturpflanze Hanf ist seit einigen Jahren wieder mit Erfolg im Anbau und wird nun auch als Dämmstoff eingesetzt. Naturfasern auf Basis von Hanf sind erfindungsgemäße besonders bevorzugt.
• - Kokosfaser-Dämmung: Aufgrund seiner hohen Strapazierfähigkeit ist Kokosfaser als Dämmstoff sehr vielseitig einsetzbar.

Examples of natural fiber insulation are:

• - Cellulose insulation: Cellulose flakes convince with their very good price-performance ratio.
• - Jute insulation: Upcycling turns old jute transport sacks into a healthy building material with good insulation properties.
• - Flax insulation: Flax is one of the oldest cultivated plants and was used as early as the Stone Age. Flax is now being rediscovered as an insulating material.
• - Hemp insulation: The cultivated plant hemp has been successfully grown again for several years and is now also used as an insulation material. Natural fibers based on hemp are particularly preferred according to the invention.
• - Coconut fiber insulation: Due to its high durability, coconut fiber is very versatile as an insulation material.

Flax insulation and / or hemp insulation, in particular hemp insulation, are preferred according to the invention.

The most common analyzes of natural fibers include a visual and haptic assessment, followed by a burn test and an examination under a light microscope (or electron microscope). The elemental composition of the natural fibers can be determined through an elemental analysis. The respective biological origin of the natural plant fibers can be proven by determining the DNA still contained in the raw material by polymerase chain reaction, or the proteins by ELISA, Western Blot or MALDI-TOF. The material properties of natural fibers are determined in the same way as for fibers in general. The different mechanical properties, such as elasticity, tensile, compressive, flexural, buckling and shear strength are determined with quantitative measurements in appropriate clamping devices. The anisotropy of the properties of fibers due to aligned molecular chains and the synergy of several twisted fibers can also be determined in this way.

New areas of application for natural fibers are technical nonwovens and fabrics for natural insulation materials, special papers or natural fiber-reinforced plastics. The use of natural fibers in fiber composites is becoming increasingly important. Natural fiber reinforced plastics can be found e.g. Used in the automotive and furniture industries. In addition, there are innovative special applications such as household appliances, cosmetic articles, writing implements, cases, urns and grinding wheels.

In the following, the hemp insulation, as a representative example of insulation based on natural fibers, will be further described. Hemp is an old cultivated plant with a wide range of uses, such as Ropes, textiles, paper, sealing material for pipe threads, oil, biomass and also for thermal insulation. Hemp insulation is based today on the low-THC varieties (THC = tetrahydrocarbinol) obtained through breeding.

Production of hemp insulation mats: The stem of the hemp plant is processed for the production of fleeces and hemp insulation mats. These are frayed by breaking and rolling. Fire protection class B2 is achieved through the addition of boron salts. Many products are used to increase the stability of hemp insulation materials Integrated polyester as a support fiber. In the meantime, however, there are also products that do without polyester fibers and instead use plant-based support fibers. A trade name for the natural insulation material hemp is, among other things, thermal hemp. Hemp insulation is offered as mat and roll goods in different thicknesses. These usually range from 30 - 220 mm. The stuffing hemp is a special form. Here the hemp fibers are offered loose.

Properties of hemp insulation: Hemp has good properties in terms of heat and sound insulation. The thermal conductivity is 0.040-0.045 W / mK. Due to the high content of embedded silica, hemp fibers are moisture-proof and rot-resistant. The insulation mats are very flexible, which makes them particularly suitable for insulation between rafters.

Application: Thermal insulation with hemp: Hemp insulation can be used in between-rafter insulation or under-rafter insulation. Furthermore for wall insulation in dry construction and for thermal insulation and footfall sound insulation of ceilings. Another possible use is as stuffing hemp. It is used to line cracks and smaller cavities, e.g. at windows. Hemp insulation is unsuitable as a plaster base for an ecological thermal insulation composite system ETICS. The material strength of the insulation mats is too low for this. However, it is possible to use hemp insulation as a ventilated facade.

Overview properties: Thermal conductivity: 0.040 - 0.045 W / mK; specific. Heat storage capacity: 2,300 J / kgK; Water vapor diffusion resistance: 1 - 2; Building material class: B2 normally flammable; Bulk density: 30 - 42 kg / m ³ ; Primary energy content: 50 - 80 kWh / m ³ . Further hemp fiber properties: fiber length single fiber 5-55, avg. 25 mm; Fiber bundle 1-3 m; Fiber diameter 10-50 µm, average 25 µm; Density 1.48 g / cm ³ ; Tensile strength 310-390 N / mm ² ; other specification: 580 - 1110 N / mm ² ; Young's modulus 69 GPa; Elongation at break 1.6-2.7%; Water absorption 8% or 8.5-10%; Chemical resistance: resistant to bases, not resistant to strong acids.

Ingredients of the hemp fiber fibers (% by weight): cellulose 75.0%; Hygroscopic water 10.0%; Pectin, lignin 9.5%; Mineral substance 0.8%; Vegetable oil and wax 0.6%; Water-soluble substances 2.1%; other ingredients 2.0%. Depending on the state of maturity of the plant, the fibers consist of 60-70% cellulose and 10-20% hemicelluloses. These proportions can vary as a result of the harvesting process and subsequent production steps such as roasting and fiber opening up to the end product. Other substances in the fibers are pectins, lignin (2 to 5%), minerals, fats and waxes. The fiber contains more lignin than flax fiber and accordingly less cellulose. It is comparatively insensitive to chemicals: it is completely insensitive to bases and only strong acids can damage the fiber.

As with all natural products, the mechanical properties of hemp fiber can vary considerably depending on the raw material and are only given as average values. The breaking strength of the hemp fiber is 23% a little higher than that of the comparable flax fiber and the specific breaking strength is about 30 breaking kilometers. The stretchability, on the other hand, is only two to three percent and the flexibility depends on the bundle structure and the fineness of the fibers. In yarns, strength and flexibility are increased by spinning hemp and flax fibers together and thus using the properties of both fibers. The water absorption capacity of the hemp fiber is around 8% of its own weight, without water leaking out and the material feeling wet.

Due to their low tendency to rot, harmless to health and resistance to pests, hemp fibers are used as insulation, e.g. for house construction, well suited and preferred according to the invention.

Alternatively, flax fibers can also be used as insulation material according to the invention: Natural insulation materials in the form of mats, panels or darning wool are made from short fibers, which are a by-product of linen production, and a little polyester is occasionally added to them for greater stability. Flax has a WLG value of 040 and is therefore comparable to wood fiber, cellulose, rock wool or polystyrene and stores heat well with a heat capacity of 1550 J / (kg * K). It is classified in building material class B2, so it is normally flammable. Although the corresponding products have established themselves as thermal insulation materials, the market share of linen in the insulation material sector is currently - together with hemp - less than 0.5%, even under optimal conditions, a market share of at most 5% is also expected for the future .

Processes for producing and processing natural fibers, and in particular for obtaining natural vegetable fibers suitable for the present invention, are known, for example, from patent publications WO 2012/104040 A1 , WO 2012/104039 A1 , WO 2008/116340 A1 , WO 2009/003606 A1 , WO 2011/047804 A1 and WO9426993 A1 . However, other known extraction methods can also be used.

1. 1) Bereitstellen einer Naturfasern enthaltenden Biomasse mit einer Trockensubstanz von höchstens 50 Gew.-%;
2. 2) Zugeben von Wasser zum Herstellen einer die Biomasse enthaltenden Suspension;
3. 3) Herauslösen der Naturfasern aus der Biomasse;
4. 4) Abtrennen der Flüssigkeit aus der Suspension;
5. 5) Trocknen der Naturfasern, wobei die Trocknung der Naturfasern eine Vortrocknung und eine Endtrocknung umfasst, dadurch gekennzeichnet, dass die Vortrocknung eine Trocknung in einem Bandtrockner umfasst und dass nur ein Teil der getrockneten Naturfasern aus dem Bandtrockner entnommen wird, während der übrige Teil dem Bandtrockner wieder zugeführt wird.

The usual methods for the provision and preparation of natural fibers, and in particular for the production of vegetable natural fibers suitable for the present invention, are described below using the example of WO 2012/104039 A1 and include the following steps:

1. 1) providing a biomass containing natural fibers with a dry substance of at most 50% by weight;
2. 2) adding water to produce a suspension containing the biomass;
3. 3) extraction of the natural fibers from the biomass;
4. 4) separating the liquid from the suspension;
5. 5) drying of the natural fibers, the drying of the natural fibers comprising a pre-drying and a final drying, characterized in that the pre-drying includes drying in a belt dryer and that only part of the dried natural fibers is removed from the belt dryer, while the remaining part is taken from the belt dryer is fed back.

In step 1 a biomass containing natural fibers is provided. These can be plant parts from different plants containing natural fibers. Plant parts which are not lignified and therefore contain only small amounts or no lignin are particularly suitable for the process described. Plant parts that are only slightly or not at all horny are also advantageous. In the case of plant fibers, cornification is usually triggered by drying. As a result of the dehydration, covalent bonds form between the cellulose molecules, making the plant fibers brittle and increasing the tendency to break. It is therefore suggested to use those parts of the plant that have not been dried.

Freshly cut grass on the one hand and ensiled grass on the other are particularly suitable for this process. In this way, fiber qualities are provided as the starting material, the dry matter contents of which are between 25 and 40% by weight. Dry matter content refers to the dry matter content that remains when all the water is removed. A dry matter content of 25 to 40% by weight therefore corresponds, conversely, to a water content between 75 and 60% by weight. Ensiling also has the advantage that the grass, which is only available at certain times of the year, can be processed throughout the year without any loss of quality. Another suitable material is rye cuttings, although other renewable, fibrous raw materials that are available depending on the region can also be used. In general, a fibrous biomass with a low lignin content, in particular a lignin content of less than 5% by weight, is proposed as the raw material. Against this background, further conceivable raw materials Bargasse, in particular ensiled sugar cane waste and spent grains, in particular beer grains containing hulls, are advantageous.

In step 2, a suspension containing the biomass is produced by adding water. For this purpose, the biomass is, for example, placed in a mixing tank, water is added and it is brought into suspension by means of an agitator arranged in the mixing tank. This suspension facilitates the further treatment of the biomass. In these processes, the suspension is produced exclusively with water, which in the subsequent steps also forms the solvent that absorbs the soluble components of the biomass. In this step, the biomass is also cleaned for the first time, with impurities adhering to the biomass and undesired accompanying substances being dissolved in the water. In this context, it is particularly advantageous that the natural fibers are released from the biomass without the use of chemicals that may be harmful to the environment. The only solvent is water.

In step 3, the natural fibers are extracted from the biomass. A macerator is preferably used to dissolve it, which separates the suspended biomass fed to the macerator into individual components and, due to the friction generated, opens the cells filled with cell fluid and allows the cell sap to escape. For this purpose, a macerator has a rotating cutting knife which brushes against a counter knife with or without contact. The counter knife can also be designed as a sieve. The result of the maceration is a suspension in which the natural fibers contained in the biomass are isolated and the liquid components contained in the biomass dissolve in the aqueous suspension.

The individual natural fibers essentially consist of alpha-cellulose and hemi-cellulose, whereby the ratio between these two types of cellulose depends on the point at which the biomass is cut. Both types of cellulose are relevant to the use of natural fibers as reinforcement fibers in a plastic compound: Alpha-cellulose enables high mechanical stability of the fibers and hemi-cellulose enables uniform absorption of the finishing agent, for example the adhesion promoter or the flame retardant. Hemi-cellulose also improves the processability of the plastic compound, in particular its flowability during thermoplastic processing. Preferred The proportions of alpha-cellulose and hemi-cellulose, based in each case on the total mass, are 20 to 30% by weight alpha cellulose and 15 to 25% by weight hemi-cellulose; the fibrous biomass particularly preferably contains 25% by weight alpha -Cellulose and 15% by weight hemi-cellulose. Overall, the proportion of alpha cellulose should be greater than the proportion of hemi-cellulose.

In step 4, the liquid is separated off from the suspension. For this purpose, the suspension is fed to a press, preferably a screw press. In the press, the liquid with the components dissolved in the liquid, such as cell water, carbohydrates, proteins and impurities, is separated from the solid contained in the biomass, the solid containing in particular the natural fibers.

In step 5 the natural fibers are dried. In the method according to the invention, this is the first drying of the natural fibers, which have always been kept moist up to this point in time. With regard to the drying temperature and the drying time, the drying is carried out in such a way that the natural fibers are not damaged and keratinization is largely prevented. Furthermore, the drying is carried out in such a way that a sufficient amount of residual moisture remains in the natural fibers so that the natural fibers do not become horny even after the drying is complete. In this context, a dry substance content of 88 to 92% by weight, at most 95% by weight, after drying is complete, is particularly advantageous. In other words, these values correspond to a residual moisture content of 5% by weight or 10 to 6% by weight. As a result, the natural fibers retain their suppleness while largely avoiding the keratinization of the natural fibers, which has a positive effect on the mechanical stability when the fibers are later used, for example as fiber reinforcement in a plastic material or as an insulating material.

In the above process, the drying can comprise a pre-drying and a final drying, a particularly advantageous drying process comprising a two-stage drying. The multi-stage drying enables gentle and energy-efficient drying of the natural fibers while largely avoiding cornification.

When drying in an air stream, it is advantageous that the natural fibers are separated from one another in the air stream. Furthermore, the natural fibers bulge up after the second drying. It has surprisingly been found that the bulkiness of the natural fibers is particularly great if the residual moisture content of the natural fibers after the first drying process is sufficiently large and amounts to at least 30% by weight. The bulkiness is of great advantage for a variety of applications. When the natural fibers are used in insulating materials and in particular as blown-in insulating material, an improved insulation value results due to the air enclosed in the fiber matrix.

The bulkiness can be quantified by a bulk weight or by determining the bulk density. To determine the bulkiness, natural fibers are blown into an open-topped, dimensionally stable container with the clear dimensions 1 mx 1 mx 0.25 m or manually filled and smeared flush on the upper edge of the container, then the mass of the natural fibers filled into the container is weighed. The bulkiness is calculated from the mass and the volume (0.25 m ³ ). Individual results and an average value from three tests must be given. A bulkiness of the natural fibers according to the invention is between 35 kg / m ³ and 60 kg / m ³ , preferably between 35 and 45 kg / m ³ .

In order to prevent cornification of the natural fibers during the entire process for providing and processing the natural fibers, the method is preferably designed so that the natural fibers always have sufficient residual moisture. It is particularly advantageous in terms of avoiding cornification if the natural fibers do not exceed a dry matter content of 90% by weight until they dry, in particular a dry matter content of 60% by weight.

To improve the stability of natural fibers, in particular of colored natural fibers, with respect to UV radiation, the means for finishing can comprise a light stabilizer. A dye enables the natural fibers to be colored, the dye adhering particularly well to the natural fibers according to the invention and thereby resulting in a continuous coloring of the natural fibers.

To reduce the flammability of natural fibers in insulation materials, the agent can comprise a flame retardant, in particular based on boron, in particular boric acid and / or borax. Suitable fire retardants are borates and borax derivatives, which are well known to those skilled in the art.

An insulating material comprises natural fibers obtainable by the method according to the invention. Such an insulation material consists of natural and biodegradable raw materials, the flammability being reduced by adding a flame retardant.

The usual flame retardants of the prior art, including the above-mentioned flame retardants based on boron, in particular boric acid and / or borax, offer flame and / or fire protection, but alone are not yet capable of initial and further To prevent smoldering and in particular no afterglowing effectively with a sufficiently high degree of security in the event of a fire or at least to delay it over a sufficient period of time and to completely prevent afterglowing.

Surprisingly, it has now been found that the addition of expandable graphite both initial and further smoldering and, in particular, afterglowing effectively with a sufficiently high level of security both in the event of a fire and after one has gone out, e.g. prevent initial sources of fire or at least delay it over a sufficiently long period of time and completely prevent afterglow. In view of the ("loose") air-containing structure of insulating materials based on natural fibers, this is extremely unexpected, not only for e.g. Fleece or felt, but also with blow-in insulation materials based on natural fibers.

The present invention surprisingly for the first time provides such ("loose") air-containing insulation materials based on natural fibers, both as e.g. Nonwovens or felts as well as blown insulation materials based on natural fibers are provided, which allow classification as B1, i.e. flame-retardant building materials (see, for example, assignment of building material classes according to DIN 4102-1 tests or according to the European classification according to EN 13501-1).

For use as insulating material, the natural fibers mixed with flame and / or fire retardants, in particular based on boron, in particular boric acid and / or borax, and according to the invention with expandable graphite, can either be formed into insulating boards or incorporated directly into a building as blown-in insulating material.

According to the invention, the isolated natural fibers consist e.g. essentially of alpha-cellulose and hemi-cellulose, the ratio between these two types of cellulose being dependent on the time at which the biomass is cut.

Both types of cellulose can be relevant to the use of the natural fibers according to the invention: the alpha-cellulose enables a high mechanical stability of the fibers and the hemi-cellulose enables a uniform absorption of finishing agents, for example the adhesion promoter or the flame retardant or the expandable graphite added according to the invention. Hemi-cellulose also improves processability, in particular its flowability, which also enables thermoplastic processing. Preferred proportions of alpha-cellulose and hemi-cellulose, based in each case on the total mass, are 20 to 30% by weight of alpha-cellulose and 15 to 25% by weight of hemi-cellulose, particularly preferably the fiber-containing biomass contains 25% by weight Alpha-cellulose and 15% by weight hemi-cellulose. Overall, the proportion of alpha cellulose should be greater than the proportion of hemi-cellulose.

According to the invention, the natural fibers can contain at least one agent for finishing the natural fibers. The finishing means converts the natural fiber into a functional natural fiber, which has special technical properties depending on the requirements and intended use. For better connectivity with expandable graphite, and e.g. even with the addition of thermoplastics, the agent can comprise an adhesion promoter. This adhesion promoter can comprise a carboxylated polypropylene, maleic anhydride in particular being used for the carboxylation. Such adhesion promoters improve the adhesion of the added expandable graphite and include the adhesion promoters known per se in the prior art, such as e.g. can also be used when plastic molecules, in particular polypropylene, are to be attached to the natural fibers in order to obtain a fiber-reinforced plastic material with improved mechanical properties.

To use expandable graphite as corona protection and / or afterglow protection for an insulation material based on natural fibers, in particular plant natural fibers used according to the invention, both as fleeces or felts and as blown insulation materials based on natural fibers, the natural fibers are mixed with fine granules and / or powder Expandable graphite, optionally present as particles in a suspension or emulsion, and furthermore optionally with the addition of an adhesion promoter, optionally also present as fine granules and / or powder and / or as particles in a suspension or emulsion, mixed, the granules and / or powder, or possibly the particles of the suspension or emulsion, is distributed in the pores of the natural fiber matrix due to the great bulkiness. Then the natural fibers provided with the expandable graphite and possibly adhesion promoter are fed to a device for further processing and for the production of the insulating materials, for example fleeces or felts as well as blown-in insulating materials based on natural fibers. By heating the natural fibers during this further processing, for example to remove the residual amounts of water, the adhesion promoter is activated by direct contact both with the natural fibers and with the added Expandable graphite forms a firm bond with both substances, so that the expandable graphite is firmly integrated into the natural fibers.

In the context of the present invention, the term “adhesion promoter” is understood to mean substances that produce a close physical or possibly chemical bond in the interface of the substances to be mixed, that is, according to the invention, the natural fiber and the expandable graphite.

The adhesive strength of coatings is defined as a measure of the resistance of a coating to its mechanical separation from the substrate; its testing is standardized in a large number of DIN and ISO standards. In the prior art, a wide range of substances is used to promote adhesion. Technically particularly important adhesion promoters are, for example, organically functionalized silanes (silane adhesion promoters) and other organometallic compounds, in particular titanates and zirconates, as well as various polymers such as polyesters and polyethyleneimine.

The mode of action of adhesion promoters can be based on a large number of properties. It is particularly important to increase the wettability of the surfaces and the possibility of forming chemical bonds between the surfaces. The adhesion promoters are either used as part of the formulation of expandable graphite for application to the natural fibers or can be applied separately to the natural fibers as part of the surface pretreatment so that the adhesion promoters develop their optimal effect directly at the respective interfaces and are therefore used in the smallest possible quantities and achieve good adhesion values.

In order for adhesion promoters to work optimally, the substrate surfaces must be clean and sufficiently reactive. In most cases, COOH or OH groups are required for the reaction with adhesion promoters. OH groups can be found on practically all natural fibers.

Adhesion promoters frequently used in the prior art are modified polyolefins. For example, a polyolefin is modified so that this previously insoluble polyolefin is soluble in organic solvents. Maleic anhydride in particular can be used for the modification. The polyolefinic adhesion promoters themselves usually do not react with the substrate, so that a reaction can then take place via the maleic anhydride. The invention, that is to say the addition of expandable graphite, can also be used when using such polyolefinic adhesion promoters.

Adhesion promoters from the substance group of the silane adhesion promoters are used above all in composites of an inorganic substrate, in the context of the present invention expandable graphite, with an organic material, in the context of the present invention the natural fibers. As a rule, they have the general form R-SiX ₃ , where R denotes an organically functionalized radical and X denotes a hydrolyzable group (mostly alkoxy groups, more rarely also -Cl). Through hydrolysis reactions with water they therefore form silanols of the form R-Si (OH) ₃ . With inorganic materials that have OH or COOH groups on the surface, silanols can enter into condensation reactions (with elimination of water) and thus form a stable bond through chemical bonds. Ideally, the Si atoms are bound into the substrate surface via all three OH groups. Alternatively, the silane coupling agents used can also react directly with the chemical groups on the surface, the condensation reaction then taking place with elimination of the alcohol or HCl. The organic group of the silane allows a connection to the natural fibers; in the ideal case this takes place through a newly formed covalent bond. The organic group R usually consists of a spacer (usually a propyl chain) and a functional group; the latter should be specific to the natural fiber that constitutes the organic layer. In principle, suitable functions, in addition to OH groups, can also be vinyl, methacrylic acid, epoxy, amino, urea or thiol groups.

According to the invention, it is advantageous if the natural fibers provided in the moist state are opened up with the addition of water before the first drying and then finished with the adhesion promoter. In this way, good absorption of the adhesion promoter in the natural fibers is achieved. On the other hand, drying before finishing would lead to cornification of the natural fibers. This would not only impair the mechanical properties of the natural fibers, but also make it more difficult to take up with the adhesion promoter.

According to the invention, the natural fibers have an adhesion promoter content which is preferably matched to the amount of expandable graphite added. For example, according to the invention, natural fibers have an adhesion promoter content of 0.5% by weight to 5% by weight; the content of adhesion promoter is advantageously between 1% by weight and 3.5% by weight, with an adhesion promoter content from 1.25% by weight to 2.5% by weight are particularly preferred.

An insulating material is a building material that is preferably used for thermal and / or sound insulation. Thermal insulation materials are materials with low thermal conductivity and reduce heat or cold losses. Soundproofing materials have a low dynamic stiffness and serve to reduce airborne or impact sound. Thermal and sound insulation materials are used in the construction industry, in plant engineering, in the manufacture of refrigerators or freezers, etc. used.

The most important physical properties of insulation materials are, for example, thermal conductivity, dynamic rigidity, bulk density, water vapor diffusion resistance, specific heat capacity and capillarity.

The thermal conductivity indicates the heat flow that passes through a substance with a layer thickness of 1 m at a temperature difference of 1 K. The lower the value, the better the insulating effect of the material. Air is a poor conductor of heat, which is why it is the main component of most insulation materials. The more air pockets there are in a fabric and the smaller they are, the more restricted the movement of the air molecules and the better the insulation performance of the material. In the case of thermal insulation materials in construction, the thermal conductivity group (WLG) is sometimes specified in addition to the thermal conductivity.

The dynamic stiffness characterizes the resilience of an insulation material. The lower the value, the better the sound-absorbing effect. Here, lightweight insulation materials with a high proportion of air have an advantage. The dynamic stiffness depends on the thickness: the thicker the insulation material, the lower the dynamic stiffness.

The gross density and the insulation or conductivity value of an insulation material are closely related; in general, the following applies: the lower the gross density of the insulation material, the higher its thermal insulation value. As a rule, the bulk density is not relevant for the material selection. For static reasons, however, this can be important in individual cases. It is often the other way around for sound insulation; A greater bulk density is also an advantage for summer heat protection.

The water vapor diffusion resistance indicates the extent to which the insulation material can be penetrated by water vapor. This (in addition to its ability to absorb or reject moisture) is important for the location where the insulation material is used. Vapor-tight constructions are necessary in areas with high vapor pressure, e.g. B. necessary in bathrooms and in the ground, while diffusion-open insulation materials in the vicinity of organic materials can help protect them. In the case of diffusion-open roofs, the penetrating moisture can be released again, while with vapor-tight roofs there is a risk that the moisture will accumulate in the wooden structure and thus contribute to its destruction in the long term.

The higher the specific heat capacity of an insulation material, the better it is suitable for keeping the heating of the interior rooms due to the sun's rays low in the summer when converting the attic (so-called “summer heat protection”). Such insulation materials also reduce the soiling of facades with ETICS through algae growth, since they cool down less strongly at night, so that less condensation forms.

Particularly in critical applications where condensation can be expected to form in the insulation material or in adjacent layers, the capillarity of the materials plays an important role in ensuring that moisture is transported to the surface of the components for evaporation. Many cases of damage have shown that the formation of a permanently functional vapor barrier is often not reliably possible under normal construction site conditions. In the case of interior insulation without a vapor barrier, condensation can even be assumed as planned in the wall structure. In this area, therefore, only insulation materials that are able to dissipate moisture in a liquid state to the wall surface are suitable. In the case of insulating materials made from renewable raw materials, sufficient capillarity can generally be assumed, provided that there is not an excessively high proportion of synthetic resin that hinders capillary transport.

Blow-in insulation materials are loose insulation materials that are introduced into a component using a blow-in machine with the help of air. There is a large number of blown insulation materials that differ in their insulation value and suitability for various purposes. Instead of blowing it in, it is also possible to use loose insulation materials as so-called tamping insulation materials.

According to the state of the art, blown insulation materials can be organic, mineral or synthetic. The main components are, for example, cellulose flakes from waste paper or meadow grass, wood fibers, grass fibers, cork, glass wool or rock wool granules, perlite polyurethane (PUR granules) or EPS granules (expanded polystyrene or gray EPS) and lightweight silicate foam. Like other insulation materials, blown insulation materials are used for thermal insulation due to their low thermal conductivity. According to the invention, blow-in insulation materials based on natural fibers of the type described above are used.

The advantages of blown-in insulation over other insulation materials are primarily the complete cavity filling in buildings that can be achieved by the blowing technique. Further advantages are the low workload and the time savings due to the simple installation. Existing constructions only need to be opened in places.

As blow-in insulation materials, the present invention preferably relates exclusively to those based on natural fibers, in particular those based on natural vegetable fibers.

Areas of application of such inventive blow-in insulation materials based on natural fibers, in particular based on natural vegetable fibers, are, for example, top floor ceilings, sloping ceilings, jamb rooms, double-shell masonry, timber frame construction, installation shafts.

Important areas of application of such inventive blow-in insulation materials are in particular places that are difficult to access in loft conversions and in energy-related renovation of old buildings. For the subsequent core insulation of the inner air layer in double-walled masonry (between the front and back wall), only blow-in insulation materials can be used. Materials approved for this purpose are usually blown into the air layer through holes in the outer wall shell. Blow-in insulation materials are also used for new buildings, especially in timber frame construction and in the area of roof insulation. Blown insulation materials made from renewable raw materials are also used in loft extensions and lightweight construction because of their high level of summer heat protection.

A new area of blown insulation technology appears in the field of installation shafts, where the present invention, including blown insulation materials, can also be used. In this way, a high level of security in preventive structural fire protection can be achieved through defined, machine-applied raw densities. This blow-in insulation technique is used in existing buildings to carry out a cost-effective, clean and time-saving retrofitting of fire protection. In the case of new installations and / or trades, this method of blow-in insulation technology can be supplemented with further potential, thus achieving an efficient construction technology. This retrospectively applicable insulation solution also solves the requirements of thermal insulation for hot pipe systems in installation shafts, so conventional pipe insulation can be dispensed with if desired. Filling the installation walls also offers the advantage that the requirements for sound insulation can be significantly improved. In addition, the filling of manholes in residential buildings also results in odor protection that eliminates existing leaks in the installation shaft across apartments.

• Ausführungsform 1: Dämmstoff, als Faserpressplatte, Faserwolle oder als Einblasdämmstoff, der in Bautengefache oder Bauelemente einblasbar ist, dadurch gekennzeichnet, dass der Dämmstoff aus Naturfasern, vorzugsweise aus pflanzlichen Naturfasern, wobei der Dämmstoff weiterhin einen Anteil an Blähgraphit von mindestens 5 Gew.-%, vorzugsweise mindestens 10 Gew.-%, und (bevorzugt) maximal bis zu 45 Gew.-%, umfasst, jeweils bezogen auf den gesamten Dämmstoff einschließlich aller ggf. eingebrachten Zusätze als 100 Gew.-%.
• Ausführungsform 2: Dämmstoff nach Ausführungsform 1, dadurch gekennzeichnet, dass die pflanzlichen Naturfasern im Wesentlichen aus Hanffasern, ggf. enthaltend übliche Dämmstoff-Zusatzstoffe, besteht oder im Wesentlichen aus Hanffasern und ggf. übliche Dämmstoff-Zusatzstoffe umfasst.
• Ausführungsform 3: Dämmstoff nach Ausführungsform 3, dadurch gekennzeichnet, dass er in teilweisem Ersatz der Hanffasern, Jutefasern, Flachsfasern und/oder Kokosfasern enthält.
• Ausführungsform 4: Dämmstoff nach einem der Ansprüche 2 oder 3, dadurch gekennzeichnet, dass er in teilweisem Ersatz der Hanffasern Fasern enthält, aus der Gruppe Cellulose, Holzfasern/Späne, Glaswolle und/oder Steinwolle.
• Ausführungsform 5: Dämmstoff nach einer der Ausführungsformen 1 bis 4, dadurch gekennzeichnet, das er Zusatzstoffe enthält, insbesondere wenigstens ein Brandschutzmittel und/oder wenigstens ein Mittel gegen Schädlingsbefall und/oder wenigstens ein Mittel gegen Pilzbefall, vorzugsweise wobei der Dämmstoff, dadurch gekennzeichnet, dass die Zusatzstoffe ausgewählt sind aus der Gruppe der Schädlingsbekämpfungsmittel, Borate, insbesondere Borax-Dekahydrat, Borax-Pentahydrat und Polybor, Kieselgur, insbesondere Kieselgur-Diatomeenerde, fossiles Plankton, aufbereitete Kieselgel-Xerogel-Mischungen mit amorphem Siliziumdioxid als Hauptbestandteil und in dem Dämmstoff einzeln oder in Kombination vorliegen.
• Ausführungsform 6: Dämmstoff nach einer der Ausführungsformen 1 bis 5, dadurch gekennzeichnet, dass die Faserlänge der Naturfasern, vorzugsweise der pflanzlichen Naturfasern, weiter bevorzugt der Hanffasern, zwischen 5 mm und 30 mm beträgt, und/oder dass das Material der Naturfasern, vorzugsweise der pflanzlichen Naturfasern, bevorzugt eine Partikelgröße, mikroskopisch gemessen, von maximal bis zu etwa 800 µm aufweist.
• Ausführungsform 7: Dämmstoff nach einer der Ausführungsformen 1 bis 6, dadurch gekennzeichnet, dass der Hanf aus einer Kurz- und Grobfaserfraktion eines Aufschlussverfahrens stammt.
• Ausführungsform 8: Dämmstoff nach einer der Ausführungsformen 1 bis 7, dadurch gekennzeichnet, dass die Zusatzstoffe trocken-pulverisiert, feinverteilt im Dämmstoff vorliegen; vorzugsweise wobei der Dämmstoff dadurch gekennzeichnet, dass die Zusatzstoffe ganz oder teilweise adhäsiv an die Naturfasern, vorzugsweise an die pflanzlichen Naturfasern, weiter bevorzugt an die Hanffasern, gebunden sind.
• Ausführungsform 9: Dämmstoff nach einer der Ausführungsformen 1 bis 8, dadurch gekennzeichnet, dass das Blähgraphit und die ggf. enthaltenen Zusatzstoffe untereinander und mit den Fasern intensiv vermengt, insbesondere miteinander vermahlen vorliegen, vorzugsweise wobei dieser Dämmstoff als Einblasdämmstoff vorgesehen ist.
• Ausführungsform 10: Bauelement mit wenigstens einer Faserpressplatte und/oder mit wenigstens einem Hohlraum, dadurch gekennzeichnet, dass die wenigstens eine Faserpressplatte des Bauelementes einen Dämmstoff nach einer der Ausführungsformen 1 bis 9 enthält, und/oder dass das Bauelement innerhalb des wenigstens einen Hohlraums einen Dämmstoff nach einer der Ausführungsformen 1 bis 9 enthält.

The present invention relates in particular, in each case independently, possibly further supplemented by one or more of the features described above or a combination thereof, as shown for example in the following embodiments:

• Embodiment 1 : Insulation material, as fiber press board, fiber wool or as blow-in insulation material which can be blown into building compartments or structural elements, characterized in that the insulation material is made from natural fibers, preferably from natural plant fibers, the insulating material also having a share of expandable graphite of at least 5% by weight , preferably at least 10% by weight, and (preferably) at most up to 45% by weight, in each case based on the entire insulation material including any additives that may be introduced as 100% by weight.
• Embodiment 2 : Insulating material according to embodiment 1, characterized in that the natural vegetable fibers essentially consist of hemp fibers, possibly containing conventional insulating material additives, or essentially comprise hemp fibers and possibly conventional insulating material additives.
• Embodiment 3 : Insulating material according to embodiment 3, characterized in that it contains a partial replacement of hemp fibers, jute fibers, flax fibers and / or coconut fibers.
• Embodiment 4 : Insulating material according to one of Claims 2 or 3, characterized in that it contains fibers from the group consisting of cellulose, wood fibers / shavings, glass wool and / or rock wool as a partial replacement for the hemp fibers.
• Embodiment 5: Insulating material according to one of embodiments 1 to 4, characterized in that it contains additives, in particular at least one fire protection agent and / or at least one agent against pest infestation and / or at least one agent against fungal attack, preferably wherein the insulating material, characterized in that the additives are selected from the group of pesticides, borates, especially borax decahydrate, borax pentahydrate and polyboron, kieselguhr, especially kieselguhr diatomaceous earth, fossil plankton, prepared silica gel-xerogel mixtures with amorphous silicon dioxide as the main component and individually or in the insulating material exist in combination.
• Embodiment 6: Insulating material according to one of the embodiments 1 to 5, characterized in that the fiber length of the natural fibers, preferably the vegetable natural fibers, more preferably the hemp fibers, is between 5 mm and 30 mm, and / or that the material of the natural fibers, preferably the vegetable natural fibers, preferably has a particle size, measured microscopically, of a maximum of up to about 800 μm.
• Embodiment 7 : Insulating material according to one of the embodiments 1 to 6, characterized in that the hemp comes from a short and coarse fiber fraction from a digestion process.
• Embodiment 8 : Insulating material according to one of the embodiments 1 to 7, characterized in that the additives are dry-powdered and finely divided in the insulating material; preferably wherein the insulating material is characterized in that the additives are wholly or partially adhesively bonded to the natural fibers, preferably to the natural plant fibers, more preferably to the hemp fibers.
• Embodiment 9: Insulating material according to one of embodiments 1 to 8, characterized in that the expandable graphite and any additives it may contain are intensively mixed with one another and with the fibers, in particular are ground with one another, preferably with this insulating material being provided as blown-in insulating material.
• Embodiment 10: component with at least one fiber pressing plate and / or with at least one cavity, characterized in that the at least one fiber pressing plate of the device includes an insulation material according to any one of embodiments 1 to 9, and / or that the component within the at least one cavity an insulating material according to one of the embodiments 1 to 9 contains.

If the present invention is to be used in particular as a blown insulation material, the present invention can then, in each case independently, optionally be further supplemented by one or more of the features described below or a combination thereof.

The DE 20 2005 004879 describes that blown insulation materials made of cellulose fibers for the thermal insulation of buildings in the state of the art are mainly produced from waste paper. All types of waste paper (white and brown paper) are shredded dry and fire retardants in powder form are added to the resulting flakes. The flakes are packed in sacks and usually blown on the construction site to isolate cavities or into the wooden cladding prepared for this purpose using so-called blowing machines. It is important to ensure that the cavities are completely filled and that sufficient material is introduced to make the finished insulation "resistant to settlement". This is the only way to ensure that all insulated surfaces on walls, ceilings and floors have a constant thermal insulation value (lambda value) over the useful life of several years. According to DE 20 2005 004879 Simply dried and cut grass or straw does not meet these requirements, it is too brittle, cannot be processed on conventional blowing machines and is easily combustible. The use of hemp and flax fibers for the production of blow-in insulation materials has also not produced satisfactory results so far. The fibers available here are long, straight and mechanically rigid and have little tendency to flake, which is a necessary prerequisite for the use of blown insulation materials. With the increasing recycling cycle of the waste paper, the cellulose fibers become more and more brittle. This fact is due to the increasing "keratinization" (embrittlement) of the fibers during the papermaking process (renewed whipping in water, pressing, drying). As a result, the manufacturers of cellulose insulation increasingly receive waste paper raw materials that contain an increased proportion of brittle cellulose fibers. The effects on the quality of the blown insulation material cannot be avoided. The user has to struggle to an increasing extent with the development of dust and with problems during the blowing-in process and with security against settlement.

The DE 20 2005 004879 Now creates a blown insulation material that can be made from inexpensive grass qualities (fresh or silage) that meets the legal requirements for cellulose insulation materials (building law approval), that can be processed economically on commercially available blow-in machines, that when blown in has a lambda value of at least 0.04 W / kxm and which is resistant to settlement, namely a blow-in insulation material made of (plant-based) natural fibers (grass), which is made from 100% moist (plant-based) natural fibers (grass, fresh or silage) and which when dry is cellulose / hemicellulose -Content of at least 80 wt .-%, characterized in that the (vegetable) natural fibers (the grass) is broken down into its components and the cellulose / hemicellulose-containing fibers contained therein from the other components of the (vegetable) natural fibers (the grass) ) are completely separated. Such (vegetable) natural fibers can be used well according to the invention with expandable graphite, as described above.

The ones in the DE 20 2005 004879 Blown insulation materials described on the basis of natural fibers can therefore also be used within the scope of the present Invention are used, because it is achieved that the insulating material can be made from abundant, renewable grass in constant quality. It is no longer necessary to use recycled fibers. By using moist grass, the cell walls of the fiber plant can easily be mechanically opened and the other components can be separated by simple solid / liquid separation. The separated moist natural fibers can then be cleaned with water. For the finished insulation material, this means a significantly improved resistance to mold compared to dry processed fiber plants, which is of decisive importance for the application as an insulation material.

Another advantage of the present invention is illustrated as follows. To ensure the necessary fire protection, boron salts (or other fire retardants) are dissolved in water and added to the moist (vegetable) natural fibers. The boron salts are absorbed into the (vegetable) natural fibers like a dye and guarantee even and sustainable fire protection even when only 5 - 10% by weight (based on the dry weight of the fibers) are used. The advantage over the use of dry, powdery fire retardants is that when the fire retardants are processed dry, the salts can only accumulate on the surface of the fibers. When processing the insulating material (blowing in) or through other mechanical influences (fiber friction when the insulating material settles in the filled cavity or formwork), there is always the risk of the salts becoming detached from the fibers and thus weakening the fire protection. This risk is avoided by treating with fire retardants in aqueous fiber suspension.

Another advantageous embodiment of the invention is shown as follows. By drying the moist fibers treated with fire retardants in a moving hot air stream, the (vegetable) natural fibers are given a permanent and distinctive, two-dimensional crimp. When the individual fibers meet in the air stream, a three-dimensional flake similar to wool is formed. Natural fibers that have been dried once or several times no longer show this appearance and it is therefore not observed when processing grass, flax or hemp.

The insulation material produced in this way, based on (vegetable) natural fibers, can be processed quickly and easily on commercially available blow-in machines, completely fills the intended cavities and, with a filling density of only 40 kg / m3, produces a (vegetable) natural fiber insulation material or cellulose insulation material usual thermal insulation value. The three-dimensional flake of grass fibers behaves like a spiral spring, which is compressed during the blowing process and then relaxes again at each location in the isolated volume element and builds up a constant force against the neighboring surfaces (fibers or walls). As a result, the insulation layer receives the settlement security required for certified blown-in insulation even at low filling densities.

• Ausführungsform 11: Einblasdämmstoff aus (pflanzlichen) Naturfasern (Gras), insbesondere nach einer der Ausführungsformen 1 bis 10, der aus 100% feuchtem (pflanzlichen) Naturfasern (Gras, frisch oder Silage) hergestellt ist und der im getrockneten Zustand einen Cellulose/Hemicellulose-Gehalt von mindestens 80 Gew.-% aufweist, dadurch gekennzeichnet, dass die (pflanzlichen) Naturfasern (das Gras) in seine Bestandteile zerlegt ist und die darin enthaltenen Cellulose-/Hemicellulose-haltigen Fasern von den übrigen Bestandteilen des (pflanzlichen) Naturfasern (des Grases) vollständig abgetrennt sind, und weiterhin dadurch gekennzeichnet, dass der Dämmstoff aus Naturfasern, vorzugsweise aus pflanzlichen Naturfasern, wobei der Dämmstoff weiterhin einen Anteil an Blähgraphit von mindestens 5 Gew.-%, vorzugsweise mindestens 10 Gew.-%, und maximal bis zu 45 Gew.-%, umfasst, jeweils bezogen auf den gesamten Dämmstoff einschließlich aller ggf. eingebrachten Zusätze als 100 Gew.-%.
• Ausführungsform 12: Einblasdämmstoff aus (pflanzlichen) Naturfasern (Gras), nach Ausführungsform 8, dadurch gekennzeichnet, dass den feuchten Cellulose-/Hemicellulose-haltigen Fasern Borax und/oder Borsäure und/oder andere Brandschutzmittel zugesetzt wurden und die Fasern im getrockneten Zustand einen Gehalt an Borax und/oder Borsäure und/oder anderer Brandschutzmittel von 5 - 10 Gew.-% und eine Restfeuchte von 8 - 10 Gew.-% aufweisen.
• Ausführungsform 13: Einblasdämmstoff aus (pflanzlichen) Naturfasern (Gras) nach einer der vorhergehenden Ausführungsformen 1 bis 12 dadurch gekennzeichnet, dass die Fasern während der Trocknung eine dreidimensionale, der Wolle ähnlich verfilzte Flocke bilden.
• Ausführungsform 14: Einblasdämmstoff aus (pflanzlichen) Naturfasern (Gras) nach einer der vorhergehenden Ausführungsformen 1 bis 13 dadurch gekennzeichnet, dass die getrockneten Faserflocken auf handelsüblichen Einblasmaschinen verarbeitbar sind, die vorgesehenen Hohlräume vollständig ausfüllen und bei einer Fülldichte von 40 kg/m³ eine setzungssichere Isolationsschicht bilden.
• Ausführungsform 15: Bauelement mit wenigstens einer Faserpressplatte und/oder mit wenigstens einem Hohlraum, dadurch gekennzeichnet, dass die wenigstens eine Faserpressplatte des Bauelementes einen Dämmstoff nach einer der Ausführungsformen 11 bis 14 enthält, und/oder dass das Bauelement innerhalb des wenigstens einen Hohlraums einen Dämmstoff nach einer der Ausführungsformen 11 bis 14 enthält.

The present invention relates in particular, in each case independently, possibly further supplemented by one or more of the features described above or a combination thereof; For the natural fibers that can be used, in particular natural plant fibers, see above; for example, the following further embodiments are shown:

• Embodiment 11 : Blow-in insulation material made from (vegetable) natural fibers (grass), in particular according to one of the embodiments 1 to 10, which is made from 100% moist (vegetable) natural fibers (grass, fresh or silage) and which in the dried state contains a cellulose / hemicellulose Has a content of at least 80% by weight, characterized in that the (vegetable) natural fibers (the grass) is broken down into its components and the cellulose / hemicellulose-containing fibers contained therein are separated from the other components of the (vegetable) natural fibers (des Grass) are completely separated, and further characterized in that the insulating material is made from natural fibers, preferably from natural vegetable fibers, the insulating material also having a proportion of expandable graphite of at least 5% by weight, preferably at least 10% by weight, and a maximum of up to 45% by weight, in each case based on the entire insulation material including any additives that may have been introduced as 100% by weight.
• Embodiment 12: Blow-in insulation material made of (vegetable) natural fibers (grass), according to embodiment 8, characterized in that borax and / or boric acid and / or other fire protection agents have been added to the moist cellulose / hemicellulose-containing fibers and the fibers have a content in the dried state of borax and / or boric acid and / or other fire retardants of 5-10% by weight and a residual moisture of 8-10% by weight.
• Embodiment 13 : Blow-in insulation material made of (vegetable) natural fibers (grass) according to one of the preceding embodiments 1 to 12, characterized in that the fibers form a three-dimensional flake that is felted like wool during drying.
• Embodiment 14 : Blow-in insulation made of (vegetable) natural fibers (grass) according to one of the previous embodiments 1 to 13, characterized in that the dried fiber flocks can be processed on commercially available blowing machines, completely fill the provided cavities and form a non-settling insulation layer with a filling density of 40 kg / m ³ .
• Embodiment 15: component with at least one fiber pressing plate and / or with at least one cavity, characterized in that the at least one fiber pressing plate of the device includes an insulation material according to any one of embodiments 11 to 14, and / or that the component within the at least one cavity an insulating material according to one of the embodiments 11 to 14 contains.

To improve the fire protection properties of the blow-in insulation material, for example, soda, ammonium sulfate, aluminum sulfate, aluminum phosphate, in addition to the additives already mentioned above, boric acids and boron salt or the optionally added so-called siloxanes, can be added.

The blow-in insulation material according to the invention can be processed with all common blow-in systems, can be conveyed well by an air stream and installed in a wall and roof structure so that it will not settle. At the same time, the material can be manufactured without additional fire protection agents (Euroclass E without additives) and achieves a low thermal conductivity (lambda 0.038 W / mK). The blown insulation according to the invention can be installed with a compression of 50 to 80 kg / m ³ . The settlement behavior is tested according to the following standard: ISO / CD 18393 . The machinability of the blow-in insulation depends above all on the fact that there must be no blockages in the machine, which can occur in two places: 1. In a rotary valve, which is used in almost all blow-in machines; 2. In the hose, in which the material is conveyed in an air stream after passing the rotary valve.

A typical insulation board made of natural fibers will be described using the example of hemp fibers, e.g. a facade insulation board made of hemp fibers. This hemp fiber insulation board can be glued and / or dowelled.

The typical properties are: renewable raw material; highly diffusible; very good summer heat protection; very good acoustic properties. Thermal conductivity: 0.045 W / (m * K) according to DIN 4108-4 ; Heat storage capacity: 1700 J / (kgK); Diffusion resistance factor µ (H ₂ O) => µ ≈ 2 according to DIN EN 12086 ; Gross density approx. 100 kg / m3 (± 20 kg / m ³ ); Hemp reveal insulation board: approx. 135 kg / m ³ ; Fire behavior class E according to DIN EN 13501-1 (normally inflammable, without the inventive addition of expandable graphite); Dynamic stiffness ≤ 5 (MN / m ³ ) according to DIN EN 29052 ; Length-related flow resistance r: ≥ 5 (kPa * s / m) according to DIN EN 29053 ; Format eg 800 x 625 mm (of course any other formats are also possible); Edge formation usually blunt; Panel thickness reveal insulation panels: 20-40 mm (without pre-drilled dowel holes) (of course any other panel thicknesses are also possible); Facade insulation panels: 60-240 mm (of course, any other panel thicknesses are also possible); Insulation panels ≥ 140 mm can, for example, consist of at least two bonded individual panels.

The invention here also expressly relates to bulk goods and foam, pressed, felt, fleece and / or composite products. Thus the invention relates, e.g. as bulk goods, generally also natural fibers of the type described above, containing or consisting of the agent defined above for reducing the flammability and / or combustibility of insulation materials, in particular flame retardants and / or fire retardants, and mixed and / or made up with expandable graphite. The invention also relates to products made therefrom or comprising them, which are further processed into foam, pressed, felt and / or composite products.

Insulations according to the invention prove to be particularly advantageous through the use of expandable graphite, since, in particular in the case of vertical insulation and vertical wall coverings for fire or flame protection tests, flame has to be applied to the edges vertically in order to provide the required fire protection certificates. The flamed vertically arranged material, i.e. the vertical insulation or the vertical wall covering, must neither melt nor drip in order to pass the required fire protection test and fire protection class. A glow and / or afterglow should also be avoided. This has so far not been successful in the state of the art, as catastrophic fires of, in particular, styrofoam and also of insulation materials of the state of the art based on wood and cellulose products show in the recent past. It is known that flames in fires usually spread very easily from bottom to top, i.e. vertically upwards. In the event of fire, dripping occurs due to the fusing of e.g. from the binder and / or glue contained in the wood fibers and / or cellulose fibers, and especially the polyolefin-based substance of the type described above contained in the materials and / or (pre) products. the insulation materials constantly melting, dripping binding agent, glue and / or polyolefin down into the edge flame from above and constantly ignites the flame formation and the fire.

The present invention now succeeds for the first time, in particular through the use of expandable graphite in the above-described materials and / or (preliminary) products in the (vertical) edge flaming, a fusion or a drop by fusing the binder and / or glue contained, for example , and, if applicable, of a polyolefin-based substance possibly contained in the materials and / or (pre-) products and thus to prevent the formation of flames and the spread of a fire, or at least to make it more difficult for a sufficient period of time until Fire-fighting forces on site can take further fire-fighting measures. The prevention of glowing or afterglowing found according to the invention plays a decisive role here.

In the broadest version of the invention, especially in the case of fibrous materials and / or (pre-) products pretreated with a further flame retardant and / or fire retardant, the amount of expandable graphite can vary within a wide range, the amount of expandable graphite being in the expandable graphite-containing materials and / or (preliminary) products up to 30 wt .-% based on the material and / or product and / or preliminary product, but preferably not more than 25 wt .-% based on the total expandable graphite containing material and / or (pre-) product as 100 wt .-%. If the proportion of expandable graphite is more than 30% by weight based on the material and / or product and / or preliminary product used, problems may arise, including occur in terms of thermal conductivity.

The minimum amount of expandable graphite in the materials and / or (preliminary) products containing expandable graphite should be at least 4% by weight, in each case based on the material and / or product and / or preliminary product used, alternatively at least 5% by weight , alternatively at least 6% by weight, alternatively at least 7% by weight. Preferably, based in each case on the total expandable graphite-containing material and / or (pre-) product as 100% by weight, the minimum amount of expandable graphite in the expandable graphite-containing materials and / or (pre-) products is at least 8% by weight. %, more preferably at least 9% by weight, particularly preferably at least 10% by weight.

According to the invention, the proportion of expandable graphite in the above-described materials and / or (pre-) products or uses or processes, in particular in configurations consisting of or comprising polyolefin-based substances of the type described above, is preferably not more than 25% by weight , preferably not more than 20% by weight, more preferably not more than 15% by weight, and very particularly preferably not more than 12% by weight, based in each case on the entire material and / or (pre) product than 100 Wt%.

According to the invention, the proportion of expandable graphite in the above-described materials and / or (preliminary) products or uses or processes is at least 4% by weight, preferably at least 5% by weight, more preferably at least 6% by weight, even more preferably at least 7% by weight, and very particularly preferably at least 8% by weight, 9% by weight or 10% by weight, each based on the entire material and / or (pre) product as 100% by weight .

According to the invention, the proportion of expandable graphite in the above-described materials and / or (pre-) products or uses or processes, based in each case on the entire material and / or (pre-) product as 100% by weight, thus in the range of 4 wt% to 30 wt%, from 5 wt% to 30 wt%, from 6 wt% to 30 wt%, from 7 wt% to 30 wt%, from 8 wt% to 30 wt%, from 9 wt% to 30 wt%, and from 10 wt% to 30 wt%. The proportion of expandable graphite is preferably in the range from 4% by weight to 25% by weight, from 5% by weight to 25% by weight, from 6% by weight to 25% by weight, from 7% by weight Wt% to 25 wt%, from 8 wt% to 25 wt%, from 9 wt% to 25 wt%, and from 10 wt% to 25 wt%. The proportion of expandable graphite is more preferably in the range from 4% by weight to 20% by weight, from 5% by weight to 20% by weight, from 6% by weight to 20% by weight, of 7 wt% to 20 wt%, from 8 wt% to 20 wt%, from 9 wt% to 20 wt%, and from 10 wt% to 20 wt% %. The proportion of expandable graphite here is very particularly preferably in the range from 4% by weight to 15% by weight, from 5% by weight to 15% by weight, from 6% by weight to 15% by weight, from 7 wt% to 15 wt%, from 8 wt% to 15 wt%, from 9 wt% to 15 wt%, and from 10 wt% to 15 wt% -%. All of the above percentages by weight relate to the entire material and / or (pre-) product as 100% by weight.

In a particular embodiment of the invention, the proportion of expandable graphite is in the range from 8% by weight to 14% by weight, from 8% by weight to 13% by weight, from 9% by weight to 15% by weight. %, from 9% by weight to 14% by weight, from 9% by weight to 13% by weight, and particularly preferably from 10% by weight to 12% by weight, based on the entire material and / or (pre) product as 100% by weight.

Surprisingly, it has also been found according to the invention that the unwanted afterglow of products consisting of or comprising natural fibers can be effectively prevented in practice, provided expandable graphite is used.

The above amounts of expandable graphite are preferably in the form of a combination and / or mixture with boric acid (H ₃ BO ₃ ) and / or borax (Na ₂ B ₄ O ₇ * 10H ₂ O). If necessary, at least one alkali metal chloride, preferably sodium chloride, can also be present in an amount of less than 5% by weight.

According to the invention, the natural fibers are used in combination with expandable graphite. Expandable graphite, also called "expandable graphite", is made from the naturally occurring mineral graphite. A graphite flake consists of layers of honeycomb carbon atoms. Within the layers, the atoms are very firmly connected by covalent bonds. There are only weak binding forces between the layers, so that molecules can be embedded (intercalated) between the graphite layers. The storage of acids, usually sulfuric acid, converts graphite into expandable graphite.

If expandable graphite is heated, the graphite flakes expand, depending on the quality, from a temperature of approx. 140 ° C to a multiple of the original volume. As the embedded compounds evaporate, the graphite layers are driven apart like an accordion. The expanded flakes have a "worm-like" appearance and are usually several millimeters long. Physical properties of flake graphite: carbon content 85-99% by weight; Expansion rate 30-400 cc / g; Particle size 80% <75 µm - 80%> 500 µm; Start temperature 140 - 230 ° C.

To produce expandable graphite, natural graphite flakes are treated in a bath of acid and oxidizing agent. Commonly used oxidizing agents are hydrogen peroxide, potassium permanganate and chromic acid, although the latter can have after-effects. Concentrated sulfuric acid or nitric acid are mostly used as the compound to be stored, the reaction taking place at temperatures of 30 ° C. to 130 ° C. for up to four hours. After the exposure time, the flakes are washed with water and then dried. The starting temperature and expansion rate depend on the fineness of the graphite. One of the main applications of expandable graphite is flame protection. When exposed to heat, expandable graphite expands and forms an intumescent layer on the material surface. This slows down the spread of the fire and counteracts the most dangerous consequences of fire for humans, namely the formation of toxic gases and smoke.

However, the application in connection with natural fibers and / or natural fiber products was not previously known and we are here presented by the inventor for the first time. The amount of expandable graphite to be used in the context of the present invention is measured by the person skilled in the art so that smoldering and / or afterglow is effectively prevented and the expansion rate to the desired and / or acceptable depending on the application or natural fiber and / or natural fiber product Measure is set.

The expandable graphite can be used either alone or as a mixture together with the above-known flame and / or fire retardants in the production of flame and / or fire-retardant products consisting of or comprising natural fiber and / or plant natural fiber materials .

Based on the amount by weight of the natural fibers used, possibly pretreated, as 100% by weight, the amount of expandable graphite can be used in a wide range of amounts, as stated above in% by weight, based on the amount by weight of the natural fibers used as 100% by weight .-%, can be varied; Intermediate values of the stated minimum amounts in% by weight are also possible, e.g. in 0.1 wt.% steps, 0.5 wt.% steps and / or 1 wt.% steps. Likewise, the minimum amount and the upper amount of expandable graphite, as stated above in% by weight, in each case based on the amount by weight of the natural fibers used, can be 100% by weight; Intermediate values of the mentioned minimum amounts and / or excess amounts in% by weight are also possible, e.g. in 0.1 wt.% steps, 0.5 wt.% steps and / or 1 wt.% steps.

Polymeric diphenylmethane diisocyanate (PMDI) can be used as a binder and / or adhesive for the fibers. Polymeric diphenylmethane diisocyanate (PMDI), also known as technical MDI, is a mixture of methylene diphenyl isocyanates and homologous aromatic polyisocyanates. The term "polymeric diphenylmethane diisocyanate" is incorrect, it is not a polymer, but the mixture of substances contains compounds with several (typically up to 6) phenylene groups, each with an isocyanate group. A common trade name is also polymethylene polyphenyl isocyanate. PMDI is usually used as a binder in wood-based panels, especially OSB panels, and is a starting material for the production of polyurethanes. Industrial production takes place by phosgenation of 4,4'-diaminodiphenylmethane (an MDA) and its homologues. This mixture itself is in turn produced by the condensation of aniline with formaldehyde. The composition and properties of the PMDI with regard to reactivity and thus its usability as a binder are essentially influenced by the following factors: proportions of the MDI isomers (4,4'-MDI, 2,4'-MDI, 2,2'-MDI); Molar mass distribution. PMDI is a brown, very severe Flammable liquid (flash point above 200 ° C), which has a higher density than water. The melting point is around -24 ° C. At 20 ° C the density is around 1.23 g cm ^-3 . With regard to wood chipboard materials with PMDI, PMDI has a number of advantages compared to other adhesives used in the wood-based materials industry, which definitely justify the higher price, especially for applications that place higher demands on moisture resistance or formaldehyde emissions: hydrolysis resistance; formaldehyde free; lower binder requirement.

In an exemplary embodiment, natural fibers (with residual moisture) were poured into a concrete mixer and added to expandable graphite (a wide range of 4% by weight - 30% by weight of expanded graphite is possible; preferably, for example, a range of 10% by weight) - 12 wt .-% additive expandable graphite) mixed. A PMDI solution was then sprayed on, the mixture was poured into a press mold and pressed into a fleece. The natural fiber product produced in this way has sufficient strength and shows no burning, no afterglow after 10 minutes of exposure to the flame. The temperature of the burned surface fell suddenly. Expandable graphite has an intumescent effect and expands at the point of fire, prevents the natural fibers from igniting, does not allow the temperature to rise inside the fleece, extinguishes immediately after removing the flame and does not continue to glow. Classification in fire protection group B1 would therefore not be a problem.

In an exemplary embodiment, natural fibers were first placed or completely soaked in boric acid and / or borax solution and then dried again. Then the treated natural fibers were poured into a concrete mixer as in the previous variant and also sprayed with PMDI, then poured into a press mold and pressed into fleeces. The strength of the natural fiber board as a fleece was also very good, it does not burn, the burned surface still radiates a little temperature, the afterglow is very low and after 20 minutes no afterglow could be observed, the temperature decreased quickly and any glowing spots extinguished Completely.

The advantageous effects of the invention in connection with expandable graphite are illustrated in more detail in the example of this application.

In use, the agent according to the invention is allowed to act and / or be drawn in for a time customary for the respective material and can then be used in the usual manner familiar to the person skilled in the art for the flame and / or fire-proof material or product (product, composite material, composite material, insulating material, Processing building material etc.).

The quality of a treated material and / or substance remains unchanged and is not adversely affected.

Further advantages and advantageous configurations of the invention can be found in the following examples and the claims. All of the features presented in the description, the following examples and the claims can be essential to the invention both individually and in any combination with one another. The mode of operation of the invention is therefore to be described in more detail below using examples, but without wishing to restrict the scope of the invention. The scope of the invention is defined in the claims and is supported by the above detailed description. The examples serve for further explanation.

Examples

Example 1: Flame retardant applications for expanded graphite - experiments with natural fiber insulation boards

Example 1a (comparison):

In a first attempt, natural fibers were poured into a concrete mixer and initially sprayed with the flame retardant (boric acid / borax) and then sprayed with a PMDI binder (formaldehyde-free binder with very little use, previously urea in the state of the art). After sufficient mixing, the treated natural fibers were pressed into natural fiber insulation boards under high pressure and temperature.

The natural fiber panels produced did not burn down quickly, despite being exposed to a flame for 10 minutes, but only very slowly through internal afterglow, which is caused by the stored internal ignition temperature and the oxygen present. This phenomenon is the actual main problem, which is why such a natural fiber insulation board of the prior art does not achieve a fire certificate (B1).

Example 1b (comparison):

In a further experiment, the PMDI was mixed with two different fire retardants. Since the PMDI reacts with water and water was contained in both fire retardants used, these attempts were not successful either. The tests gave rise to the hypothesis that boric acid and / or borax from the fire retardants protect the natural fibers well and thus the PMDI glowed afterwards. Therefore, additional phosphonate based fire retardants were applied, but this was also unsuccessful.

Example 1c (comparison):

Further tests with different mixing variants of fire retardants were intensified and tests carried out in a similar way to the failed tests above: Natural fibers were mixed with 20% by weight boric acid flame retardant and 5% by weight phosphonate-based flame retardant and 0.3% by weight -% PMDI sprayed, mixed and pressed into natural fiber boards. The natural fibers, however, were too wet and could hardly be glued together, and yet they continued to glow in the fire / flame test, and even after complete drying it still glowed.

Example 1d (according to the invention):

• Erfindungsgemäßer Versuch 1: 500 g Naturfasern, insbesondere Hanf, wurden mit 12% Restfeuchte in einen Betonmischer eingefüllt, dann 120 g Blähgraphit (möglich ist auch mit weniger und mehr, insbesondere im Bereich 1 Gew.-% - 60 Gew.-% bezogen auf Gewichtsmenge der Naturfasern als 100 Gew.-%) zudosiert und 5 Min. durchmischt. Es wurden dann 0,3 Gew.-% PMDI (bezogen auf behandelte Naturfasern als 100-Gew.-%) aufgesprüht, Das Mischgut wurde in eine Pressform eingefüllt und zu einer Faserplatte verpresst. Das erhaltene Naturfaserplatten-Erzeugnis wies die für die Praxis erforderliche Festigkeit auf, Nach 10 Min. Beflammung wurden kein Brennen und kein Nachglühen beobachtet, die Temperatur der Brandfläche sank schlagartig. Blähgraphit wirkte intumeszierend, blähte an der Brandstelle auf, verhinderte das Entzünden der Cellulose, ließ keine Temperatur ins Innere des Faser-Dämmstoffs, erlosch sofort nach Entfernen der Flamme, und glühte keineswegs nach. Somit wies das erfindungsgemäße mit Blähgraphit geschützte Naturfaserplatten-Erzeugnis Brandschutzeigenschaften für zumindest ein B1-Zertifikat auf.
• Erfindungsgemäßer Versuch 2: Naturfasern, insbesondere Hanf, in wurden Borsäure- und/oder Borax-Lösung eingelegt bzw. vollständig eingetränkt, in einer Menge wie im allgemeinen Teil der Anmeldung beschrieben. Diese behandelten Naturfasern ließ man wieder trocknen, sie wurden in einen Betonmischer eingefüllt und mit 0,3 Gew.-% PMDI (bezogen auf behandelte Naturfasern als 100-Gew.-%) besprüht, sodann in eine Pressform eingelegt und zu einer Faserplatte verpresst. Die Festigkeit der erhalten Naturfaserplatte war ebenfalls sehr gut, sie brannte bei Beflammung nicht, die Brandfläche strahlte nach Beflammung noch etwas Temperatur aus, das Nachglühen war aber sehr gering, und nach spätestens 20 Min. wurde kein Nachglühen mehr beobachtet, die Temperatur nahm ab, die ggf. bei Beflammung beobachtete Glut erlosch vollständig.

The above failed attempts were modified into experiments according to the invention. Two representative tests were carried out for this purpose:

• Experiment 1 according to the invention : 500 g natural fibers, in particular hemp, were poured into a concrete mixer with 12% residual moisture, then 120 g expandable graphite (is also possible with less and more, in particular in the range 1 wt .-% - 60 wt .-% based on Amount by weight of the natural fibers as 100% by weight) and mixed for 5 minutes. 0.3% by weight of PMDI (based on treated natural fibers as 100% by weight) was then sprayed on. The mixture was poured into a press mold and pressed to form a fiber board. The natural fiber board product obtained had the strength required in practice. After 10 minutes of exposure to the flame, no burning and no afterglow were observed, and the temperature of the burned surface dropped suddenly. Expandable graphite had an intumescent effect, puffed up at the point of fire, prevented the cellulose from igniting, did not allow any temperature into the interior of the fiber insulation material, went out immediately after removing the flame and did not continue to glow. The natural fiber board product according to the invention protected with expandable graphite thus had fire protection properties for at least a B1 certificate.
• Experiment 2 according to the invention : natural fibers, in particular hemp, were placed in or completely soaked in boric acid and / or borax solution, in an amount as described in the general part of the application. These treated natural fibers were allowed to dry again, they were poured into a concrete mixer and sprayed with 0.3% by weight PMDI (based on treated natural fibers as 100% by weight), then placed in a mold and pressed to form a fiber board. The strength of the preserved natural fiber board was also very good, it did not burn when exposed to a flame, the burned surface still radiated a bit of temperature after exposure to the flame, but the afterglow was very low, and after 20 minutes at the latest no more afterglow was observed, the temperature decreased, any embers observed when the fire was exposed to fire extinguished completely.

Example 2:

In the case of insulation, for example in the form of foam, pressed, felt, fleece and / or composite (pre-) products, consisting of or comprising natural fibers as well as adhesives and / or binders and / or glues and / or possibly also Polyolefin-based materials, the use of expandable graphite has proven to be very beneficial.

The invention can therefore be carried out for the configurations relating to materials and / or (pre-) products which consist of, in particular, natural fibers containing binders and / or glue, by adding materials and / or (pre-) products to reduce them the flammability and / or combustibility, in particular as a flame retardant and / or fire retardant, expandable graphite is incorporated directly.

For example, a composition optionally containing additives and optionally also boric acid and / or borax and containing expandable graphite is applied to a treated or untreated foam, pressed, felt, fleece and / or composite (pre-) product (or from it carrier formed) as powder and / or granules sprinkled on or introduced by mixing and / or, if present as a solution or emulsion or suspension, this is sprayed on or introduced by mixing.

The use of expandable graphite in the materials and / or (pre-) products described makes it possible, in the event of (vertical) edge flaming, a fusion or a droplet by fusing the e.g. contained binding agent and / or glue, and especially of polyolefin-based substances contained in the materials and / or (pre-) products such as in particular polyethylene, polypropylene and / or polystyrene, to effectively prevent and thus prevent the formation of flames and the spread of a fire , or by suppressing glowing and / or afterglowing, at least over a sufficient period of time.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2017/081240 A1 [0002]
• WO 2017/118765 A1 [0002]
• WO 2012/104040 A1 [0040]
• WO 2012/104039 A1 [0040, 0041]
• WO 2008/116340 A1 [0040]
• WO 2009/003606 A1 [0040]
• WO 2011/047804 A1 [0040]
• WO 9426993 A1 [0040]
• DE 202005004879 [0089, 0090, 0091]

Non-patent literature cited

• DIN 60001-1 [0022]
• DIN EN ISO 6938 [0022]
• ISO / CD 18393 [0097]
• DIN 4108-4 [0099]
• DIN EN 12086 [0099]
• DIN EN 13501-1 [0099]
• DIN EN 29052 [0099]
• DIN EN 29053 [0099]

Claims (10)

Insulating material, as fiberboard, fiber wool or as blown-in insulation that can be blown into building compartments or structural elements, characterized in that the insulating material is made from natural fibers, preferably from natural plant fibers, the insulating material also having a share of expandable graphite of at least 5% by weight, preferably at least 10% by weight, and a maximum of 45% by weight, in each case based on the entire insulation material including any additives introduced as 100% by weight. Insulation material after Claim 1 , characterized in that the plant-based natural fibers essentially consist of hemp fibers, possibly containing conventional insulation additives, or essentially comprise hemp fibers and optionally conventional insulation additives. Insulation material after Claim 3 , characterized in that it contains partial replacement of the hemp fibers, jute fibers, flax fibers and / or coconut fibers; and / or characterized in that it partially replaces the hemp fibers with fibers from the group consisting of cellulose, wood fibers / chips, glass wool and / or rock wool. Insulation according to one of the Claims 1 to 3 , characterized in that it contains additives, in particular at least one fire retardant and / or at least one agent against pest infestation and / or at least one agent against fungal attack, preferably wherein the insulating material, characterized in that the additives are selected from the group of pesticides, borates , in particular borax decahydrate, borax pentahydrate and polyboron, kieselguhr, in particular kieselguhr diatomaceous earth, fossil plankton, prepared silica gel-xerogel mixtures with amorphous silicon dioxide as the main component and in the insulation material individually or in combination. Insulation according to one of the Claims 1 to 5 , characterized in that the fiber length of the natural fibers, preferably the natural plant fibers, more preferably the hemp fibers, is between 5 mm and 30 mm, and / or that the material of the natural fibers, preferably the natural plant fibers, preferably a particle size, measured microscopically, of has a maximum of up to about 800 µm. Insulation according to one of the Claims 1 to 5 , characterized in that the additives are dry-powdered, finely divided in the insulation material; preferably wherein the insulating material is characterized in that the additives are wholly or partially adhesively bonded to the natural fibers, preferably to the natural plant fibers, more preferably to the hemp fibers. Insulation according to one of the Claims 1 to 6th , characterized in that the expandable graphite and any additives that may be present are intensively mixed with one another and with the fibers, in particular ground with one another, preferably this insulating material being provided as blown-in insulating material. Blow-in insulation made from (vegetable) natural fibers (grass), in particular according to one of the Claims 1 to 7th which is made from 100% moist (vegetable) natural fibers (grass, fresh or silage) and which has a cellulose / hemicellulose content of at least 80% by weight in the dried state, characterized in that the (vegetable) natural fibers ( the grass) is broken down into its components and the cellulose / hemicellulose-containing fibers contained therein are completely separated from the other components of the (vegetable) natural fibers (the grass), and further characterized in that the insulating material is made from natural fibers, preferably from vegetable Natural fibers, the insulating material also comprising a proportion of expandable graphite of at least 5% by weight, preferably at least 10% by weight, and a maximum of 45% by weight, in each case based on the entire insulating material including any additives than 100% by weight. Blow-in insulation made from (vegetable) natural fibers (grass), according to Claim 8 , characterized in that borax and / or boric acid and / or other fire retardants have been added to the moist cellulose / hemicellulose-containing fibers and the fibers have a borax and / or boric acid and / or other fire retardant content of 5 - 10 wt .-% and a residual moisture content of 8-10% by weight. Component with at least one fiber board and / or with at least one cavity, characterized in that the at least one fiber board of the component is an insulating material according to one of the Claims 1 to 9 contains, and / or that the component within the at least one cavity contains an insulating material according to one of the Claims 1 to 9 contains.