DE102006061991A1 - Material for the production of a shaped body and shaped body - Google Patents

Abstract

A material for producing a shaped body which has a heat- and / or pressure-activatable polymer and at least one filler is characterized in that the shaped body contains ten to ninety percent by weight Coir Fiber Pith (CFP).

Description

The The invention relates to a material according to the preamble of the claim 1 for producing a shaped body, which is a heat- and / or pressure-activatable polymer and at least one filler having, wherein under molding not just finished products such as commodities, but Precaution as well as intermediates such as so-called Pellets, tablets or granules are understood, which for further processing intended for finished products. Furthermore, the invention relates to a Moldings.

In recently, Time is becoming more and more objects not just made of pure polymer, but of a mixture of polymer and one of wood fibers or wood particles or wood flour existing filler. This under the name Wood plastic composites (WPC) known material has many Benefits, but now has the disadvantage that it is more expensive Since wood has become a commodity in many areas Application and therefore has become scarce. So has the demand after the raw material wood flour or wood pulp lately Enormously increased, because this raw material as an energy source for heating purposes in the form of wood pellets. This has huge price increases and led to a shortage of the raw material wood. In addition, there is the world increasing demand for wood for the pulp production.

There in the WPC, the bond between the polymers and the wood pulp often is insufficient, the mixture of thermoplastic polymers and the wood pulp a binder as a primer such as Lignin derivatives and / or polyester resins, acrylic resins and maleic acid compounds added. Under the influence of heat and pressure, this mixture can then WPC be reshaped. The addition of binders or adhesion promoters is very expensive and therefore represents a major cost factor, which the end products become more expensive.

It is the object of the invention, an aforementioned material and moldings such form that they are cheaper to produce.

The solution This object is apparent from the features of the characterizing Part of claim 1. Advantageous developments of the invention emerge from the dependent claims.

According to the invention is a material for producing a shaped body, which is a heat and / or pressure-activatable polymer and at least one filler characterized in that the material is ten to ninety Weight percent Coir Fiber Pith (CFP) contains.

Thereby, that the material contains ten to 90 weight percent CFP can be dispensed with existing from a wood pulp filler. This has an extremely beneficial effect on the production costs. Because CFP is a renewable resource, the fiber extraction from the outer fruit peel of the coconut (Latin name: "cocos nucifera ") each Year in millions of tons and is currently not used or only to a limited extent. The outer fruit shell of the Coconut weighs about five hundred Grams and consists of about thirty Percent of coconut fiber and about seventy percent CFP.

CFP can be obtained by using the outer shell of the coconut (HUSK) is defoamed. Defibration causes CFP. Furthermore remains a residual HUSK, which is made of thin outer skin the coconut persists and about another fifteen to thirty millimeters thick layer with a fibrous structure and CFP has. This residual HUSK can be ground or to a particle size of smaller 5000 microns crushed and used as a filler. The Specification of grain size refers refers to the commonly used indication of maximum extension a grain.

Furthermore Also the non-defatted coconut shell (HUSK) in fresh Condition or dried ground or to a size smaller 5000 microns crushed and used as a filler. hereby would be a mixture of materials arise, which is about thirty percent abridged or ground coconut fiber contains and about seventy percent CFP has.

It has been surprising shown that by the action of pressure and temperature in the CFP-containing lignin can be easily activated and plasticized can. This makes it even possible that on the addition of pressure and heat activated Polymers as polymer matrices (lignin compounds) as far as possible can be waived.

One Another advantage of CFP as a filler is that this does not rot and a very low water absorption and thus has a very low swelling capacity in water. hereby receives a from the material according to the invention existing molding a very high dimensional stability in the outdoor application and when exposed to water and moisture.

In addition, it has been found that CFP is already under pressure from Tempe plasticized from 120 ° C and thus leads to stable moldings.

to Production of a molded article is very good a mixture of CFP with thermosetting and / or thermoplastic polymers and copolymers. Polymers and copolymers are organic substances that have polymeric structure. These are in particular thermoplastic polymers, elastomeric polymers, thermosetting polymers including the group of so-called biopolymers or natural polymers Compounds such as vegetable lignin and starch polymers.

Under moldings Although not only, but especially objects understood, which under heat and pressure application, thereby curing, whereupon they end products form.

In front- or intermediates such as pellets, tablets or granules can by thermoplastic injection molding, extrusion or hot pressing be prepared, the temperature effect may only be so great that the natural CFP Lignin is not thermally activated and / or cured.

For example For the preparation of tablets is a mixture of 68.5 weight percent CFP with a residual moisture content (water content) of less than ten percent and with a particle size of less than 3000 Microns and thirty Weight percent polyvinyl chloride powder (PVC with a K value of seventy and a melting point of 172 ° C) and 1.5 weight percent Sodium stearate powder mixed intensively in a forced mixer at 20 to 25 ° C. This mixture will over a tablet press (rotary) under the influence of 35 kilonewtons to homogeneous tablets with one Diameter of about four millimeters and a thickness of about four millimeters pressed. The specific gravity of these shaped bodies is 0.890 grams per millimeter.

In similar Way can be produced as a homogeneous, free-flowing pellets molded body. For example, a mixture of seventy percent by weight CFP with a residual moisture (water content) of less than ten percent and a particle size of smaller 4000 microns and 25 weight percent polypropylene powder as well five percent by weight Alkali lignin powder, made from the black liquor, at the production of pulp by Astron or sulfate pulp process accrues, mixed in a screw mixer and continuously for compacting in a pelleting plant (flat die press) with pug mill and Punching disc and rotating cut-off knives too homogeneous moldings in the form of cylindrical pellets with a diameter of three Millimeters and a section length of about five millimeters pressed. Due to the frictional heat, the temperature increases this process to about 55 ° C. The homogeneous pellets have a specific gravity of about 0.25 Grams per milliliter and a smooth, wood-like surface as well a homogeneous material structure.

The solid but not plasticized tablets or pellets can in thermoplastic injection molding or activated by compression under the action of heat and pressure, plasticized and processed into stable moldings. The Drawing from the above mixtures produced moldings by a great dimensional stability also at Temperatures above 80 ° C, low Water absorption of less than one percent, weathering resistance as well as high mechanical strength. Furthermore, a very good dimensional stability given in case of fire and fire. In addition, let the Shaped body easily process, that is it can conventional Wood processing technology can be applied. As an example of final products can Bottom plates, tubes, window profiles or other hollow body called become.

One another example of a material according to the invention, which is particularly suitable for post elements, which have a very high resistance to bending and bending is, is a mixture of sixty percent by weight CFP with a particle size smaller 4000 microns and with a residual moisture content of about eight percent and 35 percent by weight shredded mixed plastic, in particular polyethylene film waste, as well as five percent by weight Titanium dioxide, which by means of a fast-running feed screw a Lochmatrize (ring matrix disc) fed and with a special arranged pressure plate is compressed. By the resulting frictional heat, at 145 ° C Because of the high pressure, the polyethylene became melt flow incorporated into the CFP and pressed through the hole die. By built-in cooling disks The temperature was before cutting with a rotating knife to 60 ° C reduced. The diameter of the perforated disc was about three millimeters. By means of the rotating knives was the plasticized and compacted Mass to strand granules cut. This resulted in a free-flowing homogeneous granules a density of 1.05 grams per milliliter. This homogeneous granules can on conventional Be processed twin-screw extruders.

Another example of the application of the invention is the continuous production of pellets based on CFP and polypropylene on a single screw extruder with upstream strand pelletizer, via hole disc and cutting blade. For this purpose, a mixture of sixty percent by weight of CFP having a particle size of about 3000 microns and having a residual moisture content of about eight percent and forty percent polypropylene (homopolymer) was used. The mixture was fed via hopper dosing an extruder and plasticized at 185 ° C and formed into granules. The mass temperature is in the range between 185 and 205 ° C. The granules have a specific gravity of 1.08 grams per milliliter.

The Granules are very homogeneous and can be used on all conventional Processing machines for thermoplastics, such as extruders, injection molding machines and hot presses, be further processed. The granules could in particular without post-drying on conventional injection molding machines, Single- and twin-screw extruders are processed into molded parts and profiles become.

Corresponding DIN 1087-1 on moldings conducted Measurements have shown that test bars, which were prepared from the latter granules, a water absorption of less than one percent, according to DIN ISO 527 a tensile strength of about 45 MPa and a tensile modulus of 5800 MPa, according to DIN ISO 178 a bending strength of about 70 MPa and a bending modulus of 4800 MPa and according to DIN ISO 179 a Charpy toughness of about 13 KJ / m2.

To the A comparison was made of a WPC granulate of the composition: 40% by weight Polypropylene and 60 weight percent spruce wood flour also on an injection molding machine sprayed into test bars. At these test bars could with the identical test methods the following values are found: Water absorption greater than four Percent, tensile strength less than 43 MPa, tensile modulus of elasticity less than 5200 MPa, Bending strength less than 62 MPa, bending modulus less than 4200 MPa, Charpy toughness Stark less than 11 KJ / m2. These test values clearly show that shaped body made of polypropylene with CFP much better material properties to have. Particularly noteworthy is the very low water absorption the polypropylene CFP molding.

Although in the material according to the invention also basically can be dispensed with the addition of lignin compounds, so it has proved to be advantageous in certain applications the material mixture lignin compounds or lignin derivatives add. A lignin derivative has proved to be very advantageous here, which is a calcium hydroxide lignosulfonate complex and / or a reaction product based on a calcium hydroxide-lignin sulfate complex is as provided in a particular embodiment of the invention is.

Surprised was found by the addition of calcium hydroxide lignosulfonate complexes in the extrusion of profiles of CFP and polyvinyl chloride as well other polymers such as polypropylene, the thermoplastic polymer portion can be significantly reduced and also CFP with a water content for example, 25 percent or more are processed without problems can. In particular, the latter is very advantageous since CFP in the Extraction of coconut fibers using the traditional method regularly a water content of up to eighty percent by weight is obtained and consuming before processing into moldings and costly to a residual moisture of less than fifteen weight percent must be dried. By using CFP with a higher water content Thus, a significant cost savings can be achieved.

Of Further takes CFP with a water content of less than fifteen weight percent due to its relatively large size surface and its structure again very easily moisture or water on, which is why when stored a water content of about fifteen to twenty percent by weight.

One example for the latter embodiment The invention is a mixture containing fifty percent by weight of CFP a particle size smaller as 4000 microns, as well as five weight percent of a commercial Lubricant and stabilizer mixture, fifteen percent by weight polypropylene granules and thirty percent by weight Calcium hydroxide lignosulfonate complex in powder form and water insoluble. These Blend ingredients were added to a twin screw extruder three degassing zones and downstream plate profile tool via separate Metering devices fed continuously and at a temperature from 180 to 200 ° C extruded to profile plates. The extruded plate profiles thus produced showed a homogeneous material structure and were characterized by an extremely low Water absorption as well as very good mechanical properties in terms of flexural strength, Abrasion and dimensional stability too im elevated Temperature range at about 90 ° C.

Another example of the latter embodiment of the invention is the production of granules in a twin-screw extruder. To the twin-screw extruder, 70 parts by weight of CFP having a water content of less than twenty-five percent (equivalent to about 52.5 weight percent dry CFP), eighteen parts by weight of dry, water-soluble lignosulfonate powder recovered from the sulfite liquor of the pulp industry, fifty-five parts by weight of calcium oxide (CaO ) in powder form, ten parts by weight of PVC with a K-value of five and sixty and a melting point of 155 to 165 ° C and two parts by weight stabilizer and lubricant mixture based on magnesium stearate supplied.

by virtue of the exothermic reaction between the residual water contained in the CFP and the CaO was reacted with the lignosulfonate powder of CaO to the calcium hydroxide lignin complex and plasticization of the total mixture and granulation by the granulator downstream of the extruder. excess unbound water escaped through degassing facilities. As a result became a free flowing obtained thermoplastic granules based on conventional Extrusion injection molding or pressing equipment for thermoplastic molded parts could be further processed.

One another example of the preparation of a granulate according to the invention is the mixture of one hundred parts by weight of CFP with a water content of about fifty percent with one hundred and twenty parts by weight of dry, water-soluble Lignosulfonate powder obtained from the sulfite waste liquor of the pulp industry, in a cooling-heating mixer, after which the mixture then in one hundred and fifty Parts by weight of calcium oxide (CaO) added in powder form and mixed becomes. An exothermic reaction took place, which turned into a crumbly Granules resulted in the calcium lignosulfonate complex embedded in the cell pore matrix of the CFP.

This Product can be heated by means of heat presses under the influence of Pressure and temperature are pressed into three-dimensional moldings.

Of course it is it also possible with the addition of further polymer components such as polypropylene this product on injection molding machines, hot pressing or extruders to form parts to process.

When a material has also proved particularly advantageous which five to fifty, preferably about thirty Percent by weight of coconut fibers, preferably with a length of three to five Millimeters, contains. By the addition of coconut fibers with a length of about three to five millimeters the flexural strength of extruded moldings has been increased.

Furthermore let yourself the addition of coconut fibers very easy to realize. Because the HUSK exists about seventy percent CFP and about thirty percent coconut fiber. Therefore you can grind or chop the HUSK and after Successful drying of the mixture. This can be done during granulation, Pelletier- or extrusion process happen.

Especially It is advantageous that the HUSK only has a water content of about fifty Percent, whereby the drying before grinding or Crushing or after grinding or crushing with relatively little energy can be done. In addition, with the green, not in the water stored outer coconut shells the lignin compounds in the CFP have not yet changed oxidatively, so that you get a very light regrind.

Very Also advantageous is a material which is five to sixty percent by weight milled coconut shell, preferably with a particle size smaller than 500 microns. The addition of ground coconut shell allows the proportion of polymer or significantly reduce copolymer. Furthermore, will by the addition of coconut shell the rotting resistance of the molded body produced from the material significantly increased.

at another particular embodiment The invention provides that the material is five to fifty percent by weight having expanded perlite. By the addition of expanded perlite, preferably with grain or particle sizes of less than 500 microns, is achieved in an advantageous manner that the strength of a material of the invention increased final product. In particular, it increases the bending strength. Furthermore, such a final product a very high heat capacity, and although under extreme conditions such as exposure to fire. Very It is also advantageous that perlite compress in a similar manner as CFP to form bodies or shapes.

When example for Such a material may be given a mixture, which from fifty Weight percent CFP with a particle size less than 4000 microns and with a water content of less than twelve percent (residual moisture), 25 percent by weight expanded perlite with a particle size of 150 microns, 2.5 Percent of lignosulfonate powder (as a primer), one weight percent Calcium oxide in powder form and 21.5 weight percent polypropylene with a melting range of 165 to 175 ° C consists.

The mixture can be fed by means of a screw mixer, a Flachmatrizenpresse with pug mill and be pressed at a temperature of about 55 ° C to form pellets. The pellets can be plasticized via a twin-screw extruder at 180 ° C and extruded into final products such as plates. The shaped bodies thus produced are characterized by high Bending strength, have a low abrasion and are very dimensionally stable even under the action of temperatures up to 150 ° C. Plates with a thickness of about twenty millimeters withstand exposure to fire and temperatures above 1000 ° C. Therefore, such panels are very well suited as fire protection, for example, in doors.

Of course you can the above mixture also directly, that is without to compress them into pellets, directly via an extruder or by means of a hot press to moldings (especially plates) are processed.

Farther has become a special embodiment of the invention which contain one to forty percent by weight highly porous Polymers with a pore volume of at least thirty percent, preferably more than fifty Percent. It became surprising found that it is very beneficial when the polymers or copolymers a porous Have structure with a pore volume greater than thirty percent. The use of such Polymers or copolymers leads at a pressure and / or heat activation to a very firm binding of the polymers or copolymers to the CFP. This in particular, if the residual moisture of CFP greater than ten percent.

A further improvement of the latter two embodiments can be achieved by having in the pores or cells of the expanded perlite or the highly porous polymers binders, adhesion promoters and / or additives are incorporated. Because in the production of moldings CFP also in blending with other fillers, especially in the direct extrusion process, it is, depending on the requirement profile to the final product, required, special binders, primer and / or to incorporate other additives. The addition and the handling such additives, especially if they are liquid products and / or binders, adhesion promoters and / or additives, which consist of several components and, for example, such as curable liquid polyester resins only after the addition (metered addition in the mixing and molding process) with each other to react is very problematic and partially unrealizable. By filling the pores of the expanded perlite or the cells of the highly porous polymers with binder, adhesion promoter and / or additives, these can be easily and very precisely dosed incorporated into the mixture.

In similar Way can the material of the invention be further improved by the fact that the expanded perlite or the highly porous Polymers coated with binder, adhesion promoter and / or additives is or is. This makes it possible, the binder, adhesion promoter and / or additives very easy to introduce into the mixture, wherein they can also be dosed very accurately. Distribute further the binders, adhesion promoters and / or additives are very uniform in the melt flow.

following will be an example of manufacture with reference to the single figure a shaped body specified from CFP.

The fruits 1 The coconut palm (cocos nucifera) becomes after the harvest from the outer Fruchtschale 2 , the so-called HUSK, which made the very thin outer skin 2a (Called "Skin") and the Coir Fiber Pith 2 B and the Coir Fibers 2c (Coconut fibers), mechanically released. The HUSK 2 a complete fruit 1 weighs on average about 500 grams calculated as dry weight. From the HUSK 2 wrapped is the well-known coconut 3 , It is fed as actual coconut fruit to other processing processes.

The HUSK 2 is stored in water, softened and then the HUSK 2 Degreased in a mechanical process by means of spiked rollers. There are about thirty percent coconut fibers 2c and about seventy percent CFP 2 B in which the defatted residual HUSK, which is also referred to as HUSK chip, is one of the proportion of coconut fibers.

The resulting CFP 2 B has a water content of about eighty percent. The particle size of the CFP 2 B is predominantly in the range between 2000 to 3500 microns. This CFP 2 B , which still depends on the used defibering process coconut fibers 2c containing between twenty and fifty millimeters in length, is now screened to these fine fibers 2c to remove.

The wet CFP 2 B is now subjected to a drying process in air or placed in a rotating tube dryer or circulating air dryer to a residual moisture content of fifteen to twenty percent water content.

For this CFP 2 B can now be prepared with the addition of pressure and / or heat-activatable polymers, copolymers and so on moldings. For this purpose, a twin-screw extruder with opposite screw guide and downstream tube tool via a metering device polypropylene is supplied as well as a further metering the CFP. The blend ratio of polypropylene to CFP is about thirty parts by weight polypropylene and seventy parts by weight CFP. The temperature in the screw zone is about 185 to 205 ° C. According to DIN ISO 1183, the polypropylene had a density of 760 kilograms per cubic meter, and according to DIN ISO 53730 a melt flow index (205 ° C and 21.6 N) of eight grams per ten minutes, according to DIN ISO 527, a tensile strength of more than 32 MPa and a tensile modulus of greater than 1700 MPa.

Of the CFP had a natural one Lignin content of about 59 percent. On the addition of adhesion promoter based on maleic acid, as with comparable mixtures of wood flour, could be omitted become. The feeder The CFP into the extruder was made so that the polypropylene already in the melt flow.

It was surprising that when extruding pipes with a wall thickness of 8.5 millimeters, the polypropylene intimately with the CFP to homogenize and stable moldings with very good surface smoothness and extrude excellent flexural strength and heat capacity left.

at comparable mixtures based on wood flour and / or wood fibers this is without the addition of very expensive adhesive mixtures (compounds) not possible. At least have to special, in maleic acid and duroplastic resins grafted polypropylene granules for Use come, which are very expensive.

Claims (11)

Material for producing a shaped body which has a heat- and / or pressure-activatable polymer and at least one filler, characterized in that the shaped body contains ten to ninety percent by weight Coir Fiber Pith (CFP). Material for producing a molded article according to Claim 1, characterized in that it lignin compounds or Lignin derivatives has. Material according to claim 2, characterized that the lignin compound is a calcium hydroxide lignosulfonate complex is and / or a reaction product based on a calcium hydroxide lignosulfonate complex. Material according to one of claims 1 to 3, characterized that it comprises binders and / or other additives. Material according to one of claims 1 to 4, characterized that he is five to fifty Percent by weight of coconut fibers, preferably with a length of three to twenty-five Contains millimeters. Material according to one of claims 1 to 5, characterized that he is five to sixty percent by weight ground coconut shell, preferably with a particle size smaller than 1000 microns. Material according to one of claims 1 to 6, characterized that he is five to fifty Has percent by weight expanded perlite. Material according to one of claims 1 to 7, characterized that it contains one to forty percent by weight of highly porous polymers with a pore volume at least thirty Percent, preferably more than fifty Percent. Material according to claim 7 or 8, characterized that in the pores or cells of the expanded perlite, respectively the highly porous Embedded polymeric binders, adhesion promoters and / or additives are. Material according to one of claims 7 to 9, characterized that the expanded perlite or the highly porous polymers coated with binder, adhesion promoter and / or additives respectively are. Moldings, characterized in that it comprises a material according to any one of claims 1 to 10 having.