Use of waxes as modifying agent for filled plastics

The invention relates to the use of waxes as modifying agents for fillers containing thermoplastic or thermosetting plastics that such Waxes.

Fillers generally powdered or fibrous substances are organic understood or inorganic origin, which, in organic media Dispersions or emulsions are dispersed to the respective final product to impart certain properties or to reduce its cost price. The fillers, inorganic and organic materials have to distinguish will. Of particular importance are calcium carbonate, calcium magnesium carbonate, Aluminum silicates, silica, magnesium silicates (talc), Barium sulfate, aluminum potassium sodium silicates, metals and oxides, Aluminiumhydoxide, carbon blacks and graphite, wood and cork flour, wood chips, wood fibers, Glass fibers and natural fibers (HP "Schlumpf," Filler and Reinforcements "in R. Gächter, H. Müller, Plastic Additives, 3rd Edition, Carl Hanser Verlag, Munich 1993 S.525 - 591).

Fillers are used in a wide range of applications. Specifically, Here the plastic applications, paints, coating materials, paper, building materials and to name adhesives. Depending on the application, various properties of the Fillers relevant. Typical parameters are the refractive index, the Binder pickup, the specific surface area, the opacity, the abrasion (Wear of the processing equipment), the gloss, the particle shape and the Particle size distribution. Particularly in the case of fibrous fillers is the Compatibility between the filler and matrix of particular interest. to Improve this connection between the two materials are eg Glass fibers with suitable substances coated.

Over the past decades, the importance of fillers increased in the Plastics Processing steadily. While in the past the filling material in the first Line either a cheapening of the final product or the quantitative aspired increase of the finished article, we took advantage of in the aftermath of the impact Fillers on the processing properties and the properties of the Finished products. With the help of fillers properties were as Processing speed, the dimensional stability, flammability, the Abrasion resistance, dielectric strength, or mechanical Properties are optimized. In the field of plastics processing Fillers, in particular in polyvinyl chloride, polyethylene, polypropylene, and also Rubber (natural and synthetic non-crosslinked and crosslinked, for example by Vulcanization, elastomers). Engineering thermoplastics (polycarbonate, Polymethyl methacrylate, polyamide, polystyrene, etc.) are only rarely fillers added.

For a variety of applications have wood-filled thermoplastic Plastics established as prior art. Here are wood flour, wood fibers or Wood chips incorporated in high concentrations. Are usual in this case filling ratios of 50 to 90 wt .-%. The matrix material are commercially available thermoplastics used. In particular, here are polyvinyl chloride, polypropylene and the different types of polyethylene mentioned. Rare are also technical Thermoplastics such as polystyrene or other styrene polymers (eg, ABS). In addition to these main components are in such applications also some additives used to optimize the properties. Thus, in low Quantities polymers modified to improve the mechanical properties added. Unsolved problems are so far the rapid aging of these materials under changing weather conditions and the poor dimensional stability due to the Water absorption of the incorporated into the plastic timber.

Surprisingly, it has been found that the addition of waxes to filled Plastics provides performance advantages. The use of appropriate Products affect the property profile of the molding clearly positive. It will raised the mechanical characteristics under tensile and bending stress.

Further, the water absorption of hydrophilic fillers is retarded and reduced. At the same time an improved dimensional stability is achieved. The invention therefore relates to the use of waxes as an additive to filled Plastics.

It is preferable that when the waxes are synthetic or natural Waxes.

It is preferable that in the natural waxes are petroleum waxes, Montan waxes, animal waxes and / or vegetable waxes.

It is preferable that in the synthetic waxes are fatty acids, Fatty acid esters, fatty acid amides, Fischer-Tropsch waxes, polyolefin waxes and / or polar-modified polyolefin waxes.

It is preferable that in the natural waxes are montan waxes. Montan waxes are ester waxes and / or salts of carboxylic acids. It deals in particular, reaction products of montan wax acids with polyhydric low molecular weight alcohols.

It is preferable that in the natural waxes, for example, Vegetable waxes such as carnauba or candelilla waxes or animal Origin such as shellac wax into question. Suitable semisynthetic waxes are for example, bleached, optionally chemically eg by esterification and / or modified by partial hydrolysis montan waxes. Appropriate Products are for example in Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol A 28, Weinheim 1996 Chapter 2.2, 2.3 and 3.1-3.5, p. 110 - 126 described.

Preferred is polar or nonpolar fully synthetic waxes, eg Polyolefin. Non-polar polyolefin waxes may be prepared by thermal degradation a branched or unbranched polyolefin plastics or by direct Polymerization are made of olefins. As the polymerization are, for example free-radical processes in question, wherein the olefins in the Generally ethylene, at high pressures and temperatures to a greater or lesser branched waxes are implemented; next process in which ethylene and / or higher 1-olefins with the aid of organometallic catalysts, for example, Ziegler-Natta or metallocene catalysts, to give unbranched or branched Waxes are polymerized. Appropriate methods for the preparation of Olefin homopolymer and copolymer waxes are, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A 28, Weinheim 1996 Chapter 6.1.1 / 6.1.2- (high-pressure) Cape. 6.1.3. (Ziegler-Natta polymerization, Polymerization using metallocene catalysts), and chap. 6.1.4 (thermal degradation), S. 146-154 described. Polar polyolefin waxes are formed by appropriate Modification of nonpolar waxes, for example by oxidation with air or by Grafting of polar olefin monomers, for example, α, β-unsaturated Carboxylic acids and / or derivatives thereof, such as acrylic acid or maleic anhydride and / or subsituierte and / or non-substituted styrenes and / or vinyl silanes. Further can polar polyolefin waxes prepared by copolymerization of ethylene with polar Comonomers, for example vinyl acetate or acrylic acid are produced; continue by oxidative degradation of higher molecular weight, non-waxy ethylene homo- and copolymers. Relevant examples can be found for example in Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A 28, Weinheim 1996, chap. 6.1.5, S. 155th

Preferably at The polyolefin homo- and copolymers various alkenes.

Preferably at The polyolefin homo- and copolymers of ethene and propene.

Preferably at The polyolefin homo- and copolymers prepared on Ziegler or metallocene catalyst contact.

Preferably, in the polyolefin to polar modified Polyolefin.

Preference is for the polar-modified polyolefin Oxidation products or graft copolymers.

It is preferable that in the graft to radically Products made of polyolefin waxes described and one or more polar Monomers. Preferably, the monomers are maleic anhydride, alkoxy Vinyl silanes and styrenes.

It is preferable that in the graft products with a Dropping point from 90 to 170 ° C.

Particularly preferably, in the graft to products a dropping point of 110 to 150 ° C.

It is preferable that in the graft to products with a Melt viscosity at 170 ° C from 0.1 to 10,000 mPas.

Particularly preferably, in the graft to products a melt viscosity at 170 ° C of 1 to 1000 mPas.

It is preferable that in the graft products with a Degree of grafting of 0.1 to 20%.

Particularly preferably, in the graft to products a degree of grafting of 2 to 10%.

the waxes are preferably used in an amount of 0.05 to 10 wt .-%, based on the filler used.

the waxes are particularly preferred in an amount of 0.5 to 5.0 wt .-%, based on the filler, are used.

Preferably, the fillers are inorganic and / or organic Fillers.

It is preferable that the inorganic fillers are calcium carbonate, Calcium magnesium carbonate, aluminum silicates, silica, magnesium silicates (Talc), barium sulfate, aluminum potassium sodium silicates, metals and oxides and / or aluminum hydroxides. Preferably, the organic fillers are carbon black and graphite, Wood and cork flour, wood chips, wood fibers, glass fibers and natural fibers and / or organic pigments.

the fillers are preferably used in an amount of 1 to 99 wt .-%, based on the total mixture used.

the fillers are particularly preferred in an amount of 50 to 90 wt .-% based on the total mixture.

The invention also relates to a thermoplastic or thermosetting plastic, containing 1 to 99 wt .-% of a wax-coated with the described Filler.

Preferably it is a thermoplastic or thermosetting Plastic, containing 50 to 95 wt .-% of a wax-coated filler.

It is preferable that in the thermoplastic, vulcanizable (rubber) or thermosetting plastic polyvinyl chloride, polyethylene-HD (High Density) Polyethylene LD (low density), polyethylene LLDPE (linear low density), Polypropylene, natural rubber, synthetic rubber, polycarbonate, Polymethyl methacrylate, polyamide, styrene polymers and / or blends of various plastics is.

For the introduction of the wax in the mixture there are various Options: For the wax in an existing or new Step can be applied as an aqueous dispersion. Furthermore, there is the Ability to atomize a wax melt and so applied to the filler. In addition, a mixture of filler and wax in a mixing unit (Eg blade mixer) are homogenized. Furthermore, it is possible the wax directly volumetrically into the processing machine or without further premix gravimetric dosing and thus only then the contact between the individual produce components.

Examples

Commercial wood chips was with different waxes and a premixed commercial polyethylene-HD and then was this Mixture in an extruder compounded. The granulated compounds were processed by injection molding to give moldings. These parts were various Investigations subjected. In the experiments, a course on the market Product included as comparison. These recipes are marked with B and represent the state of the art.<sl><li>Compound A containing 70 wt .-% wood chips and 30 wt .-% HDPE.</li><li>Compound B containing 1.5 wt .-% of a commercially available additive for the System wood / polyethylene and 70 wt .-% wood chips and 28.5 wt .-% HDPE.</li><li>Compound C containing 1.5 wt .-% of a maleic anhydride grafted Metallocene polyethylene wax as an additive for the wood / polyethylene and 70 system Wt .-% wood chips and 28.5 wt .-% HDPE.</li></sl>

Characterization of the novel additive:<sl><li>Polyethylene wax prepared by metallocene catalysis<dl tsize="11" compact="compact"><dt>Dropping point:</dt><dd>about 120 ° C</dd><dt>Acid number:</dt><dd>about 40 mg KOH / g</dd><dt>Viscosity:</dt><dd>about 220 mPas at 140 ° C</dd></dl></li></sl>

Compound Preparation: All powdered ingredients were in a Tumble mixer homogeneously mixed. This mixture was mixed with a co-rotating twin screw extruder processed to a granulate.

Prüfköperherstellung: All tests Standard dumbbell specimens were determined to DIN EN ISO 294 injection molded.

The mechanical properties were determined to DIN EN ISO 178, ISO 179 and DIN EN ISO 527 determined. The study of water uptake was by DIN EN ISO 62 performed.<tables><table><tgroup cols="4"><tbody><row><entry align="center" /><entry align="center">A</entry><entry align="center">B</entry><entry align="center">C</entry></row><row><entry align="left">Train Modulus [MPa]</entry><entry align="center">5730</entry><entry align="center">5680</entry><entry align="center">6880</entry></row><row><entry align="left">Tensile strength [N / mm²]</entry><entry align="center">25.7</entry><entry align="center">28.2</entry><entry align="center">38.4</entry></row><row><entry align="left">Tensile elongation [%]</entry><entry align="center">0.7</entry><entry align="center">0.7</entry><entry align="center">0.8</entry></row><row><entry align="left">Impact strength [kJ / m²]</entry><entry align="center">2.2</entry><entry align="center">2.9</entry><entry align="center">3.5</entry></row><row><entry align="left">Flexural Modulus [Mpa]</entry><entry align="center">4190</entry><entry align="center">4070</entry><entry align="center">4100</entry></row><row><entry align="left">Flexural strength [N / mm²]</entry><entry align="center">24.4</entry><entry align="center">29.7</entry><entry align="center">40.3</entry></row><row><entry align="left">Bending strain [%]</entry><entry align="center">0.8</entry><entry align="center">0.9</entry><entry align="center">1.2</entry></row><row><entry align="left">Water absorption after 20 days [%]</entry><entry align="center">114</entry><entry align="center">112</entry><entry align="center">107</entry></row><row><entry align="left">Water absorption after 50 days [%]</entry><entry align="center">116</entry><entry align="center">115</entry><entry align="center">113</entry></row></tbody></tgroup></table></tables>

The measured values ​​listed clearly show that the compound C by far the best properties.