DE102005061222A1 - Vegetable fiber, fiber-based shaped articles and methods of making novolak-treated vegetable fibers - Google Patents

Abstract

The invention relates to a vegetable fiber which is provided with hardener-free novolak. The invention further relates to a molded article produced using fibers according to the invention and to a method for producing the vegetable fiber according to the invention.

Description

The The invention relates to a shaped body fiber-based, which using novolac-treated vegetable fibers is produced and characterized in particular by a reduced formaldehyde emission behavior and better hydrophobic Characteristics distinguishes. The invention further relates to a Process for the preparation of a vegetable novolac Fiber.

to Production of moldings, such as mats, plates or moldings are vegetable fibers, especially wood fibers used. The vegetable fibers, in particular wood fibers are produced by using vegetable raw materials, eg pieces of wood, mechanically, e.g. in mills or in other mechanically disassembling aggregates, or thermo-mechanical or chemo-thermomechanical, e.g. in pressure fiberizing aggregates, preferably in refiners, be open-minded. It should be noted, that the sharper the digestion conditions with these methods in terms of temperature, pressure and time, the more more formaldehyde from the vegetable starting materials, in particular made of wood, is emitted.

In Refiners are made from the vegetable fibers Starting materials by defibering between grinding discs. there For example, in the case of wood, one usually works as a starting material with pressing in a range of 7 to 11 bar and temperatures of up to 185 ° C and a Dwell time of three to six minutes. Above the above conditions This can lead to considerable formaldehyde emissions.

Of the Fiber production / fiber pulping process by means of said Method can be controlled so that fibers of a given geometry and structure can be obtained.

During the Fiber production / pulping process may also be added to paraffins. The paraffins improve the sliding properties of the fibers, thereby reduces the energy expenditure in the fiber production / fiber pulping process becomes.

As well The paraffins are used to improve the hydrophobicity of the produced Fibers and the moldings produced from these fibers

adversely However, the paraffins are only in an amount of up to about 3.0% by weight, based on the absolutely dry, vegetable fiber-containing Starting material, eg absolutely dry wood (atro), added can be.

at another increase the amount of paraffin during of the fiber manufacturing / fiber pulping process degrade the bonding properties of the fibers thus produced

by virtue of the poorer bondability of the added paraffin quantities produced fibers also deteriorates the property profile the molded articles produced from these fibers.

Of others contain vegetable fibers, especially wood fibers, depending on the type of wood different amounts of naturally existing and in the vegetable raw material, especially wood, chemically bound Formaldehyde. Fiber production / fiber pulping and / or Production of the molding be released as well as in use and application of the molding. task The present invention is to provide vegetable fibers, in particular Wood fibers, where the formaldehyde release at significantly reduced in the fiber manufacturing / pulping process and the hydrophobic properties of the fiber are improved.

A Another object of the present invention is a method to provide during which of fiber manufacturing / fiber pulping process the emission of Formaldehyde is at least reduced and that the production of Fibers with low formaldehyde emission potential allows.

A Another object of the invention is to provide a shaped body Fiber base, wherein the formaldehyde emission potential is significantly reduced.

A Another object is to provide a molded article that has improved has hydrophobic properties.

The The object underlying the invention is achieved by providing a vegetable fiber provided with hardener-free novolac is solved.

preferred Further developments are specified in the dependent claims 2 to 6.

The The object underlying the invention is further by a shaped body dissolved on a plant basis, wherein the shaped body vegetable fiber according to one the claims 1 to 6 contains.

The object of the invention is further achieved by providing a method for producing a hardener-free novolak fiber according to any one of claims 1 to 6, wherein the process comprises the following step: digesting vegetable starting materials in the presence of hardener-free novolak in mechanically disintegrating aggregates, thermo-mechanically disintegrating aggregates or chemo-thermo-mechanically disintegrating aggregates, wherein hardener-free novolak is added before or during the digestion process.

The Inventors are surprising found that it is possible is that formaldehyde emission potential of manufactured vegetable Fiber materials, in particular of wood fibers, and made therefrom fibrous moldings or shaped fiber bodies significantly lower if the plant source materials while of fiber manufacturing / fiber pulping process with hardener-free Novolac be charged.

Surprisingly It was also found that the hydrophobic properties the fiber materials thus prepared and molded articles produced therefrom improve.

It has become completely surprising shown that to reduce the emission of formaldehyde, it sufficient if the vegetable fibers thus produced with hardener-free Novolac only superficially are charged. A partial area Impinging or partially enveloping the vegetable fiber, preferably wood fiber, with novolak is sufficient. Of course you can also a full-surface Charge or complete wrapping vegetable fiber with hardener-free Novolac done.

The while formaldehyde released by the fiber manufacturing / pulping process becomes of the hardener-free Novolak largely chemically bound, with a partial hardening of the Novolakes occurs or can occur.

By the chemical bonding of formaldehyde becomes the formaldehyde emission potential of such Fibers significantly reduced. Due to the binding capacity of the Hardener free Novolacs is also in the further processing of these vegetable according to the invention Fibers and in the production of moldings and the use and application of the moldings significantly reduced the formaldehyde emission.

Become fiber moldings traditionally using vegetable fibers, in particular Wood fibers, and usually formaldehyde-containing binders, Which about 90% of the world for the production of such moldings, such as Mats, plates or molded parts used binders produced.

Under Use of the vegetable according to the invention Fibers produced moldings are also characterized by significantly reduced formaldehyde emissions and improved hydrophobic properties, since that of the formaldehyde-containing Binders emitted formaldehyde during pressurized and heat taking place molding also for hardening contributes to the novolac and thus the formaldehyde is removed from the system as far as possible and can not be emitted.

in the Considering that formaldehyde for humans and the environment a big risk potential has enabled the present invention, the human health burden while of the fiber production process, the production of moldings and its Use and application significantly lower.

The Vegetable fiber may consist of any suitable vegetable source material, that usually used for the production of shaped fiber bodies will be made. The vegetable fibers can do this from one year old or perennial Come from plants.

When vegetable fiber can e.g. Flax, hemp, bast, kenaf, jute or mixtures thereof be used.

According to one preferred embodiment the vegetable fiber is a wood fiber.

The Wood fiber can be made of any wood material or any Pine, spruce, beech, poplar, etc. are produced.

The Vegetable according to the invention Fibers preferably have a length of 0.05 mm to 30 mm, preferably from 0.1 to 20 mm, on, as have been very suitable also fiber lengths from 0.1 to 10 mm, more preferably from 0.1 to 8 mm. According to one more preferred embodiment, the fiber length is 0.1 up to 5 mm.

Farther it is preferred that the novolak on the fiber of the invention uncured or only partially networked and thus at a later date, such as. in the production of moldings using formaldehyde-containing binder under pressure and Heat reliably releases any released formaldehyde. This released formaldehyde contributes to hardening of the novolak. Furthermore, it is preferred that the proportion of novolak 0.05 to 15% by weight, preferably 0.1 to 10% by weight, in each case based on the weight of absolutely dry fiber (atro) is.

It has been surprising already shown that small amounts of hardener-free novolak on the fiber surface enough to do that during the Fiber production / fiber pulping process and / or molding production as far as possible to bind discharged formaldehyde.

By which is pronounced in the novolaks existing, water-repellent methylene bridges will be an additional Hydrophobization of the plant fiber of the invention and the molding achieved. By the hydrophobization of the vegetable fibers, preferably wood fibers, will the consistency of vegetable fibers or those produced from these vegetable fibers moldings to moisture and wet elevated, since the water is largely repelled by the hydrophobic surface.

It has also been surprising showed that the invention used Hardener-free novolac the sliding properties of the vegetable raw materials during the Fiber production / fiber pulping process improves so that traditionally for water repellency and simultaneous reduction the energy expenditure during of the fiber pulping used paraffins in their amounts can be reduced.

Of the Hardener free Novolac shows until it hardens thermoplastic properties that improve the sliding properties with good distribution of the novolak on the inventively prepared Fibers with improved hydrophobization during the fiber manufacturing / fiber pulping process to lead.

Of the used according to the invention Hardener free Contains novolak preferably no curing agent, such as hexamethylenetetramine. Within the meaning of the invention will also be under a "hardener-free" novolac Novolac understood, the minor Quantities of hardener However, these amounts are so low that the novolak can only interlink imperfectly. It is essential that the novolak a sufficient binding capacity for during the Fiber pulping or while molding production having released formaldehyde. The proportion of hardener in the "hardener-free" novolak is preferably less than 1.0% by weight, more preferably less than 0.8% by weight, even more preferably less than 0.5% by weight, based in each case on the total weight of curing agent and novolac.

The to be used according to the invention Novolacs are defined as being produced in the acidic pH range Polycondensates based on phenolic components, in particular Phenol, and aldehyde components, in particular formaldehyde, in the molar ratio of the phenolic Components, in particular phenol, to the aldehyde components, in particular Formaldehyde, of 1: <1, preferably 1: 0.5 to 1: 0.9 (molar ratio of phenolic component : Aldehyde component).

Of the Hardener free Novolak may be in the form of powder, pellets, particles, pieces, melt, Emulsion and / or dispersion are present and in this form in the inventive method be added.

There the production or the digestion of vegetable raw materials based plant fibers under the action of mechanical forces or by thermo-mechanical or chemothermomechanical digestion can be done, the hardener-free Novolac in solid or liquid Form are added. The addition of the hardener-free novolak can, for example. when using Refinern for fiber pulping in the digester, the stuffing screw and / or the grinding chamber done.

in the Considering that using vegetable raw materials produced moldings in the interior of houses or in the manufacture of furniture used extensively, the invention provides an important Contribute to improving the living conditions of people and Animals.

Farther it is preferred that the molding be synthetic and / or natural Binder and optionally further additives.

synthetic Binders are preferably selected from the group of formaldehyde-based condensation resins, such as. Urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF), melamine-urea-phenol-formaldehyde (MUFF), phenol-formaldehyde (PF), phenol-melamine-formaldehyde (PMF), phenol-urea-formaldehyde (PUF), resorcinol-phenol-formaldehyde (RPF) resorcinol-phenol-urea-formaldehyde (RPUF) and mixtures thereof, and / or from the group of thermoplastic binders, e.g. based on polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyvinyl acetates (PVAc) and mixtures thereof and / or from the group of polyurethanes and isocyanates, such as. polymeric diphenylmethane diisocyanate (PMDI) and mixtures thereof selected.

According to a further preferred embodiment, the molding contains the synthetic binder preferably in the amount of 0.5 to 50 wt .-%, more preferably from 1 to 40 wt .-%, each based on the total weight of the molding pers. The remainder may be vegetable fibers and optionally present additives.

Natural binders are preferred from the group consisting of carbohydrates, tannins, Lignins, starches, Proteins and mixtures thereof is selected.

According to one further preferred embodiment contains the molded body the natural binders preferably in the amount of 1 to 50 wt .-%, more preferably of From 5 to 40% by weight, more preferably from 10 to 30% by weight, respectively based on the total weight of the molding. The rest can be herbal Fibers and optionally existing additives.

According to one another preferred embodiment are the additives from the group consisting of water repellents, Flame retardants, fungicides Bactericides, dyes, Pigments, conductivity-increasing substances and mixtures thereof are selected.

The Additives can in the inventive molding in from 0.1 to 20% by weight, preferably from 0.5 to 15% by weight, more preferably from 1 to 10 wt .-%, each based on the total weight of the molding, to be available.

The Shares of all Components add up to 100 wt .-% in the molding according to the invention.

Of the Shaped body according to the invention preferably a plate, mat or a molded part.

by virtue of the significantly reduced formaldehyde emissions are the in particular moldings according to the invention in the living and working area. For example, the shaped bodies according to the invention can be used as Base substrate for the production of furniture or floor coverings, such as for example laminate flooring, or in the motor vehicle - interior be used.

The produced according to the invention Fibers can when using suitable synthetic binders selected from the groups the binder described above can be selected, also for Production and use of moldings used for outdoor use become.

The inventive method is amazingly easy. The only important thing is that the fiber production process or the fiber preparation in the manner described in Presence of hardener-free Novolac performed becomes.

at the method according to the invention can surprisingly and advantageously also much more intense conditions during the Applied with "hardener-free" novolak be without it to a significant, preferably no, formaldehyde emission comes.

The inventive method can be both at the usual applied conditions as well as well above the usual applied conditions, e.g. with regard to the pressure of 7 to 11 bar, in particular above 11 bar. As suitable have pressures in the range of 12 to 100 bar, for example. From 12 to 20 bar proved.

Of others can also temperatures of up to 185 ° C as well as temperatures above 185 ° C, for example. Of 190 ° C to 270 ° C or 195 ° C to 250 ° C applied become. Furthermore, it has been shown that both the usual Residence times of three to six minutes as well as longer residence times under the usual used and / or increased pressure and / or temperature conditions are possible, such as from 7 to 50 minutes or from 8 to 30 minutes. As well is also a shortening the usual used residence time at elevated pressure and temperature conditions possible and useful, such as, for example, a residence time of 1.5 min at 12 bar / 190 ° C.

The using the specified pressure, and / or temperature and / or Time conditions and vegetable fibers obtained using "hardener-free" novolac, in particular wood fibers, and draw the molded articles produced therefrom improved properties, especially in terms of Formaldehyde emission and swelling.

Claims (15)

Vegetable fiber, characterized in that the vegetable fiber is provided with hardener-free novolac. Vegetable fiber according to claim 1, characterized that the vegetable fiber from annual and / or multi-year plants is made and in particular a wood fiber. Vegetable fiber according to claim 1 or 2, characterized characterized in that the vegetable fiber has a length of 0.05 mm to 30 mm, preferably 0.1 mm to 20 mm. Vegetable fiber according to one of claims 1 to 3, characterized in that the novolak on the vegetable fiber uncrosslinked or only in imperfectly networked form. Vegetable fiber according to claims 1 to 4, characterized the proportion of novolak is 0.05 to 15% by weight, based on the weight on absolutely dry fiber. Vegetable fiber according to one of the preceding Claims, characterized in that the novolak in the molar ratio of phenolic Component to aldehyde, in particular phenol to formaldehyde, from 1 is made to less than 1 in the acidic pH range. moldings fiber base, characterized in that the shaped body vegetable Fibers according to one the claims 1 to 6 contains. moldings according to claim 7, characterized in that the shaped body natural and / or synthetic Binder and optionally further additives. moldings according to claim 8, characterized in that the synthetic binder from the Group of formaldehyde-based condensation resins, such as e.g. Urea-formaldehyde (UF), Melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF), melamine-urea-phenol-formaldehyde (MUPF), phenol-formaldehyde (PF), phenol-melamine-formaldehyde (PMF), Phenol urea formaldehyde (PUF), resorcinol-phenol-formaldehyde (RPF) resorcinol-phenol-urea-formaldehyde (RPUF) and mixtures thereof, from the group of thermoplastic binders, such as. based on polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyvinyl acetates (PVAc) and mixtures thereof, and / or from the group of polyurethanes and isocyanates, such as. polymeric diphenylmethane diisocyanate (PMDI) and mixtures thereof selected becomes. moldings according to claim 8, characterized in that the natural binder from the Group consisting of carbohydrates, tannins, lignins, starches, proteins and mixtures thereof is selected. moldings according to claim 8, characterized in that the additives from the group consisting of Water repellents, flame retardants, antifungal agents, Bactericides, dyes, pigments, conductivity enhancing substances and mixtures of which is selected are. moldings according to one the claims 7 to 11, characterized in that the shaped body is a plate, mat or Molding is. Process for making one with hardener-free Novolak provided fiber according to one of the claims 1 to 6, the method comprising the step of: digesting vegetable starting materials in the presence of novolac, in mechanical disintegrating Aggregates, thermomechanical disintegrating aggregates or chemo-thermomechanical revealing aggregates, being before or during Hardener-free digestion process Novolac is added. Method according to claim 13, characterized in that the vegetable starting materials down to one fiber length from 0.05 to 30 mm, preferably 0.1 to 20 mm are digested. Method according to claim 13 or 14, characterized in that the novolak in an amount from 0.05 to 15 wt .-%, preferably 0.1 to 10 wt .-%, based on the weight of the absolutely dry fiber is added.