DE10304095A1 - Production of wood fiber-reinforced plastics agglomerate, for extrusion or injection molding e.g. to structural or molded component, from fibers, additives and plastics powder or granulate uses hot mixer then larger cool mixer - Google Patents

Abstract

In producing wood fiber-reinforced plastics agglomerate by mixing in a hot mixer and transfer to a cool mixer, a cool high-speed mixer with beater operating at 20-40 m/s peripheral velocity and mantle at 80-150[deg]C is up to 80% filled with 60-80 wt.% wood fibers of length/diameter ratio >= 5 and 1-10 wt.% additive(s), rest plastics powder or granulate. After mixing for 10-20 minutes, the mixture is transferred so that the cool mixer is 20-30% full. An independent claim is also included for the mixture per se.

Description

The invention relates to a Process for producing an agglomerate from wood fiber reinforced plastic by preparing a mixture of plastic in the form of powder or granules, wood fibers and one or more additives in a hot mixer and then Place in a cooling mixer.

In the past few years have materials gained in importance on the basis of renewable raw materials. there show in particular wood fiber reinforced plastics such as wood fiber reinforced polypropylene or polyethylene the advantage that in addition to a visually appealing a wood effect surface has good crash behavior and recyclability are given. In addition, wood fibers are harmful to health harmless and can can be disposed of easily. Furthermore, wood fibers are unlimited and available to lead to positive effects in the wood industry.

It is already known from wood fiber reinforced plastic by injection molding or extruding to produce molded parts. However, show up Disadvantages with regard to demoldability or with regard to a consistent quality as well as mechanical strength.

In a procedure of the beginning mentioned type, natural raw materials are processed with polyolefins, being hot mixer are used, their mixing tools with a peripheral speed up operated at 50 m / s. This takes place within a very short time Time intensive mixing, while heating the Mixed goods are made by friction. The mixing tool can from a floor cleaner and a fluidizing wing exist, which is offset by 90 ° is installed. An attachment of a horn tool can also be provided be around the drum circulation with the mixing container full improve. The processed mix is then a cooling mixer fed the can be carried out in a horizontal or vertical design.

The present invention lies the problem is based on a procedure of the type mentioned at the beginning to develop so that an agglomerate is available for the production of components or molded parts is suitable, in addition to good crash behavior have good mechanical properties, especially in comparison to known components in terms of tensile strength, flexural strength and impact strength are improved. A problem-free reprocessing should also be constructive simple measures possible be, whereby process parameters are not strictly adhered to should be.

According to the invention the problem essentially becomes solved by that a mixture of approximately 60% by weight to 80% by weight wood fibers with a length to diameter ratio ≥ 5, approximately 1 % By weight up to approximately 10% by weight of one or more additives and 100% by weight filled Plastic in the cooling mixer entered that as a mixer a high-speed mixer with wing tools as well heated jacket is used, the wing tool with a peripheral speed between operated in about 20 m / sec and in about 40 m / sec and the jacket on a temperature T is heated to 80 ° C ≤ T ≤ 150 ° C, that the high-speed mixer up to approximately 80% with the mixture filled is that the mix over a time t mixed with 10 min ≤ t ≤ 20 min and that the mixture thus prepared is fed to the cooling mixer designed in this way, that the degree of filling with the mixture is approximately 20 to 30%.

Through the teaching of the invention there is an agglomerate of wood fiber reinforced plastic that both can be used for extrusion as well as for injection molding. Especially when extruding with a degree of filling of more than 50% unexpectedly good product properties of the extruded body.

To tensile strength, bending strength and impact resistance To improve the forms produced, is a further development of the invention suggested that the mixture of maleic anhydride grafted (MAH) plastic with a weight fraction between 1.5 and about 9% by weight is added to the total mixture. Used as a plastic polypropylene used, MAH polypropylene is used in a proportion of preferably 1.5% by weight - 5% by weight used. When using MAH polyethylene, the proportion should in about 7 wt .-% to 9 wt .-% based on the total mixture. The Addition of this additive leads a mediation.

In order to remove one from the mold To facilitate processing in injection molding, the mixture should 0.3 Wt% to 0.5 wt% stearate such as metal stearate e.g. in the form of calcium stearate or zinc stearate can be added.

An additive in is also helpful Form of wax that also has a weight percentage between in about 0.3% by weight and 0.5% by weight with a wood fiber content of up to 60 % By weight. With a wood fiber content between 60% by weight and 80% by weight, the wax content is between 0.5% by weight and 3% by weight. The wax in particular is an ester of montanic acids (a wax / acid mixture C24 to C34).

The hot mixer itself turns on in particular a temperature between 80 ° C and 150 ° C heated, the residual heat required to melt the plastic generated by friction.

After a residence time of between 10 and 20 minutes in the hot mixer, the mixture components are bound to one another to the extent necessary so that they can be transferred to a cooling mixer with a water-cooled jacket. The degree of filling in the cooling mixer should be 20 to 30%. Compared to the hot mixer, the cooling mixer has a base area that is 1.5 to 2 times larger.

In the cooling mixer not only happens a cooling of the Mixed goods, but also a crushing to an agglomerate desired Obtain grain size. The temperature of the cooling mixer is set to a temperature so that the mix is cooled to 80 ° C ≤ T ≤ 120 ° C. Crushed still warmed Mixed material can then the cooling mixer removed and packaged after intermediate storage, if necessary.

More details, advantages and Features do not only result from the claims, the claims to be found Features - for yourself and / or in Combination - but also from the following description of a of the drawing preferred embodiment.

In principle, the only figure shows an arrangement with which an agglomerate of wood fiber reinforced plastic can be produced. To do this, use a hot mixer 10 in the form of a high-speed mixer and a cooling mixer 12 used.

The hot mixer 10 has a double jacket to which steam, oil or even water can be applied as the heating medium 14 on. There is a mixing tool in the floor area 16 rotatably arranged, the one vertical axis 18 has which can be driven by an electric motor, not shown. The mixing tool 16 can from a floor clearer designed as a wing 20 as well as fluidizing vanes 22 consist. If necessary, a horn tool is attached to improve the drum circulation when the mixing container is full. The peripheral speed of the tool 16 is approximately 20 to 40 m / sec.

To prepare the mix, put it in the hot mixer 10 a mixture of 60 to 80 wt .-% wood fibers filled with a length to diameter ratio> 5. The wood fibers themselves preferably have a length in the range between 150 μm and 500 μm, hardwood should be used as the wood. In addition, 0.3% by weight to approximately 0.5% by weight of stearate and 0.3% by weight to approximately 0.5% by weight of wax with a wood fiber content of up to 60% by weight are used as additives. % added. With a wood fiber content of 60% by weight to 80% by weight, the wax content can be 0.5% by weight to 3% by weight. Furthermore, in order to increase the tensile strength, the flexural strength and the impact resistance of components produced with agglomerates produced according to the invention, a maleic anhydride-grafted plastic with a weight fraction between approximately 1.5 and approximately 9% by weight should be added. If propylene is used as the plastic, maleic anhydride-grafted polypropylene (about 1.5 to 5% by weight) is added, and if polyethylene is used, maleic anhydride-grafted polyethylene (about 7 to 9% by weight) is added.

A neutralizing additive may also be used with a weight fraction preferably between 0.005% by weight and 0.01 wt .-%, if at least partially or if necessary, a complete one Masking of wood smell desired becomes.

The neutralizing additive can from approximately 12.5% to 15% terpineol, 7% to 10% benzeneethanol, 3 to 5% Alpha-Hexylcinnamaldehyde and balance oil such as paraffin oil or from I-nonylphenol polyethylene glycol ether (about 15% to 20%), heptanoic acid, 2-propenyl ester (approx. 1% to 3%), 2-methoxy-naphthalenes (1 to 3%), 3-butene-2-one, 4- (2,6,6-trimethyl-1-cyclohexen-1-YL) - , (E) - (approximately 0.25% to 0.5%), hexanoid acid (approximately 0.25% to 0.5%) and rest of oil like paraffin oil or from terpineol (approx. 30% to 40%), amyl salicylate (approx. 7% up to 10%), amyl cinnamaldehyde alpha (approx. 1% to 3%) and lemongrass oil (approx. 1% up to 3%) and paraffin oil consist. Another neutralizing or masking additive can be made from benzyl salicylate (approx. 3% to 5%), hexyl cinnamaldehyde (approx. 1% to 3%), Ysamber K (approx. 0.1% to 0.2%), Ketamber (approx. 0.1% to 0.25%) and the rest of the oil.

Generally speaking, through the neutralizing additive the smell or its intensity be managed.

After the mix is processed in the hot mixer for about 10 to 20 minutes, using the double jacket 14 The mixture is transferred to the cooling mixer at a temperature between 80 and 150 ° C and the mixture is heated by friction even in the melting temperature range of the plastic used 12 whose coat 27 is cooled.

A temperature is set in such a way that the introduced mix is cooled to 120 ° C to 80 ° C. At the same time a crushing.

In the exemplary embodiment is used as a cooling mixer 12 used one whose axis of rotation is vertical. Of course, a cooling mixer of horizontal design can also be used.

After the mix in the cooling mixer 12 has been cooled and shredded to the required extent, it is packed after intermediate storage, if necessary, in order to then be supplied to production sites in which desired components can be produced by extrusion or injection molding.

In particular an insert for extruders is an advantage if these are operated with a fill level greater than 50%.

Claims (16)

Process for producing an agglomerate of wood fiber reinforced plastic by processing a mixture of plastic in the form of powder or granules, wood fibers and one or several additives in a hot mixer and subsequent introduction into a cooling mixer, characterized in that a mixture of approximately 60% by weight to approximately 80% by weight wood fibers with a length to diameter ratio ≥ 5, approximately 1% by weight % to about 10% by weight one or more additives and filled up to 100% by weight of the mixture, the plastic is introduced into the cooling mixer so that a high-speed mixer with wing tool and heated jacket is used as the mixer, the wing tool with a peripheral speed operated between about 20 m / sec and about 40 m / sec and the jacket is heated to a temperature T with 80 ° C ≥ T ≤ 150 ° C, that the high-speed mixer is filled with the mixture up to a maximum of 80%, that the mixture is mixed over a time t with 10 min t t 20 20 min and that the mixture prepared in this way is introduced into the cooling mixer designed in such a way that the degree of filling with the mixture is approximately 20 to 30% AEGT. A method according to claim 1, characterized. that wood fiber one length in the range between 150 μm and 500 μm be used. A method according to claim 1 or 2, characterized in that that hardwood fibers are used as wood fibers. Method according to at least one of the preceding Expectations, characterized in that the mixture as an additive in about 0.3 % By weight to 0.5% by weight of stearate and / or 0.3% by weight to approximately 0.5 % By weight of wax with a wood fiber content of up to 60% by weight and approximately 0.5% by weight to approximately 3% by weight of wax with a wood fiber content between 60% and 80% by weight is added. Method according to at least one of the preceding Expectations, characterized in that the stearate is a metal stearate Calcium stearate or zinc stearate is used. Method according to at least one of the preceding Expectations. characterized in that an ester of montanic acid (a wax / acid mixture C24 to C34) is used. Method according to at least one of the preceding Expectations, characterized in that in particular polypropylene as plastic or polyethylene is used. Method according to at least one of the preceding Expectations, characterized in that a maleic anhydride grafted as an additive to the mixture Plastic with a weight proportion between about 1.5 wt .-% and about 9% by weight, based on the total mixture, is added. Method according to at least one of the preceding Expectations, characterized in that as maleic anhydride grafted plastic maleic anhydride grafted Polypropylene in a proportion of approximately 1.5% by weight to 5% by weight or Maleic anhydride Polyethylene is used in a proportion of approximately 7-9% by weight. Method according to at least one of the preceding Expectations, characterized in that the mixture has an odor neutralizing or at least partially masking neutralizing additive added becomes. Method according to at least one of the preceding Expectations, characterized. that the neutralizing additive with a weight percentage of preferably between 0.005% and 0.01% by weight becomes. Mix according to at least one of the previous ones Expectations, characterized in that the neutralizing additive consists of approximately 12.5% and 15% terpineol, 7% to 10% benzene ethanol, 3 to 5% alpha-hexylcinnamaldehydes and rest of oil like paraffin oil consists. Mix according to at least one of the previous ones Expectations, characterized in that the neutralizing additive made of I-nonylphenol polyethylene glycol ether (about 15% to 20%), heptanoic acid, 2-propenyl ester (about 1% to 3%), 2-methoxy-naphthalenes (1 to 3%), 3-butene-2-one, 4- (2,6,6-trimethyl-1-cyclohexen-1-YL) -, (E) - (in about 0.25% to 0.5%), hexanoid acid (about 0.25% to 0.5%) and Rest of oil like paraffin oil consists. Mix according to at least one of the previous ones Expectations, characterized in that the neutralizing additive made of terpineol (approximately 30% to 40%), amyl salicylate (approximately 7% to 10%), amyl cinnamaldehyde Alpha (approx. 1% to 3%) as well as lemongrass oil (approx. 1% to 3%) and paraffin oil. Mix according to at least one of the previous ones Expectations, characterized in that the neutralizing additive or masking additive from benzyl salicylate (approx. 3% to 5%), hexyl cinnamaldehyde (approx. 1% to 3%), Ysamber K (approx. 0.1% to 0.2%), Ketamber (approx. 0.1% to 0.25%) as well as rest of oil consists. Method according to at least one of the preceding Expectations, characterized. that the agglomerate to extrude or injection molding is used.