DD222890A1 - SHORT FIBER AMPLIFIED POLYOLEFIN MASS - Google Patents

Abstract

The invention relates to kurzfaserverstaerkte Polyolefinformmassen based on polyethylene and / or its copolymers or of polypropylene and cellulose short fibers, which can be processed by extrusion and injection molding for the production of plate and rohrfoermigen semi-finished products, profiles or moldings. To increase the level of properties and to improve the use value, peroxides are added to the mixture of polyolefin molding compositions with cellulose short fibers.

Description

263/5752/111

Short fiber reinforced polyolefin molding compounds

Application area of the invention

The invention relates to short-fiber-reinforced polyolefin molding compositions based on polyethylene and / or its copolymers or polypropylene and short staple fibers, which can be processed by extrusion and injection molding for the production of plate and tubular semi-finished products, profiles and moldings.

Characteristic of the known technical solutions

It is known to use inorganic and / or organic substances as filling or «reinforcing components for thermoplastic polymers. · As fillers and reinforcing agents z. As chalk, talc, carbon black, lime, kaolin, glass and asbestos fibers, natural and synthetic fibers, wood flour and shavings, alumina, magnesium oxide, slate, mica u _e a · called »dominated as a thermoplastic polymer matrix in addition to polyolefins, especially polyethylene, especially polyvinyl chloride, since in its processing in most cases for-incorporation of stabilizers, among other aids a further mixing process is necessary, which can be used advantageously for mixing in further filling and reinforcing components * The production of molding compounds from thermoplastics and inorganic and / or organic fillers and reinforcing materials are made from both economic and

Considerations for the saving of polymer material ale also for modifying certain performance characteristics or for the development of new fields of application · _;

It is known that the mechanical properties of filled or reinforced polymer materials are determined not only by the properties of the starting components used, but also substantially by the ratios in the phase boundary region (Plaste and Kautschuk 22 (1975) p. 626 ff). In order to improve this interaction between the polymer component used and the filling or reinforcing component, adhesion promoters are used in order to achieve improved mechanical properties. The adhesion promoters are preferably organosilicon compounds having in each case an organofunctional group tailored to the polymer component, as well as cation-active chromium complex compounds or surfactants, inter alia. So 116 050 a process for the preparation of compound! Erten plastic systems is described with pigments or fillers, for example, in DD-WP, wherein the mixing of the components in the presence of up to 110 ⁰ C heat-resistant surfactant takes place. In DE-OS 2 402 976, DE-OS 2 444 420, DE-OS 2 539 195 and DD-WP 116 051 a paste-like construction material of thermoplastic matrix material and at least one filler mineral and / or organic type is described which serves as a primer To improve the interaction at the phase interface between the polymer matrix and the foreign storage component, a trinär adhesion promoter system consisting of silanes, liquid polysulfide polymer and epoxy plasticizer, for pretreatment of the organic filling or reinforcing components with the aim of improving the mechanical properties of the composites applied (DD-WP 126 292). According to DE-OS 2,511,257, the fiber is treated with limited amounts of plasticized polymer in the presence of a lubricant. Lubricants and small amounts of plastic material in combination exercise each other

useful interactions which improve the properties of the composites made with such treated fibers over composites of lubricants-only treated fibers. US-A-3 513 067 discloses a method of making an oriented fiber-reinforced article using as fibrous materials Natural fibers, synthetic fibers, glass, metal and asbestos fibers with a length of 0.5 "to 50 mm are used. The compounding process involves up to 15% by weight of carbon black Method results in an improvement of the mechanical property level in comparison with composites without adhesion promoters. Since the adhesion promoters or bonding agent systems used are relatively expensive, their use must be reconsidered for economic reasons.

DD-PS 97 432 includes a process for the preparation of polyolefin / mineral molding compositions, preferably by combining high density or low density polyethylene, polypropylene, polystyrene or copolymers of olefins with other polymerizable compounds, such as. As ethylene-vinyl acetate, with mineral powdery fillers, such as kaolin, clay, bentonite and / or chalk and / or ground quartz sand, with improved inking and / or improved thermo oxidative stability, improved light stability and _T improved mechanical properties, if necessary with the addition of mediators, slippers and peroxides. The addition of peroxides does not increase the mechanical properties.

Object of the invention

The aim of the invention is to produce cellulosefaserverstärkte Polyolefinformmassen with higher property level and thus improved utility value.

Explanation of the essence of the invention Technical problem

The invention is based on the problem of adding more suitable additives to the polyolefin molding compounds in order to achieve higher mechanical properties.

Features of the invention;

According to the invention the object is achieved in that a short fiber reinforced Polyolefinformmasse 5 to 60% by mass, preferably 10 to 40% by mass cellulose short fibers, based on the polyolefin content and 0.1 to 30% by mass, preferably 0.1 to 15% by mass This composite material has surprisingly good mechanical properties. The cellulose fiber materials may contain up to 75% by mass, preferably up to 30 to 60% by mass, of fibrous and / or planar PVC-W constituents. The molding composition may consist of up to 60% by mass of powdered and / or globular cellulose products and / or cellulose by-products, for example microcrystalline cellulose or ground paper waste. In addition to polyethylene and / or its copolymers or polypropylene, it is also possible to use up to 10% by weight of ethylene / vinyl acetate copolymer.

embodiments

The invention is illustrated by several examples · For the embodiments, a low-pressure polyethylene having a density of 0.950 g / cnr and a melt index of 19.5 g / 10 min (50 N, 190 ⁰ C), which following mechanical properties has:

Tensile strength: 23.0 MPa

'. Bending stress: 17.4 MPa

Young's modulus off

Bending test: 0.87 GPa Impact bending strength: 100 KJ / m ² Impact bending strength: 7.2 KJ / m ²

The polyolefin molding compositions are prepared as follows: In a high-speed mixer, the cellulosic fibers are loosened at 750 to 1500 rpm at room temperature. The peroxide is added to the loosened fibers and then the powdered low-density polyethylene is added, and the fibers are again intensively sintered at 1500 to 3000 rpm The pulverulent premix thus produced is fed to a twin-screw extruder, homogenized at 473 K and granulated and injection-molded into test pieces.

VerRleichsbeispiel

Short fiber reinforced polyolefin molding compound consisting of 90 parts by weight of Mederdruckpolyethylen and 10 parts by mass of short cellulose fibers of density 1.50 g / cm *

Mechanical properties: Tensile strength: 28.0 MPa

Bending stress: 22.8 MPa

Modulus of elasticity from the bending test: 1.1 GPa Impact bending strength: 56.0 KJ / m ² Impact bending strength: 10.0 KJ / m ²

example 1

Short fiber reinforced polyolefin molding composition consisting of 89 parts by weight of high density polyethylene, 10 parts by weight of short cellulose fibers of density 1.50 g / cnr and 1 part by weight of tertiary butyl perbenzoate.

Mechanical properties: Tensile strength: 42.9 MPa

Bending stress: 24.0 MPa Modulus of elasticity from bending test: 1.07 GPa Impact resistance: 75.0 KJ / m ² , Notch impact strength: 14.1 KJ / m ²

Example 2

Course fiber-reinforced polyolefin monofin, consisting of 88.5 parts by mass of Uiederdruckpolyethylen _s 10 mass parts Cellu-

      '3

loose-cured fibers of density 1.50 g / cnr and 1.5 parts by mass peroxide type "Perkadox 14/40" * Mechanical properties; Tensile strenght:

Bending stress: modulus of elasticity from the bending test Impact bending strength: notch Bending stress resistant '^;.'''' keits

46 ,1 MPa 28 , 7 MPa 1 .4. GPa 66 _S 9

13.4. KJ / m ^c

Example. 3

Short fiber reinforced polyolefin molding compound consisting of 88.5 parts by weight of low density polyethylene ₉ 10 parts by mass of short staple fibers from industrial waste and 1.5 parts by mass peroxide type "Perkadox 14/40"'", Mechanical properties? Tensile strenght?

Bending stress; Modulus of elasticity from the bending test Impact resistance: Impact bending strength "'' ^v . '' - keiti '

43.2 MPa

27.3 MPa

1.53 GPa _r 63.1 KJ / m ²

9.6 KJ / m '

Example 4 IHll IHIlIlIH Il ΙΝΙΙΙΓΪΙΙΙ H '! ! Ill III. Ill. III

Short fiber-reinforced polyolefin molding compound, consisting of 78 ₉ 5 parts by mass of low-pressure polyethylene, 20 parts by mass of "Cexilulose curb fibers (bw fibers)" from industrial waste and 1.5 parts by mass peroxide "Perkadox 14/40" _e

Mechanical properties; Tensile strenght? 53.5 MPa

Bending stress: 38.7 MPa

Young's modulus off

  '../ the bending test: 2.2 GPa impact strength 33.2 KJ / m' impact strength: 8.6 KJ / m '

The polyolefin molding composition contains polyethylene and / or its copolymers or polypropylene and Celluloaekurzfasera. The polymer component used may also be a regenerate and may be in powder or granular form. It is also possible to use up to 10% by mass of ethylene / vinyl acetate copolymer. The cellulose short fibers may be natural cellulose fibers and / or regenerated cellulose fibers and / or mixtures, including industrial waste, where it is advantageous to treat the cellulose short fibers before or during the preparation of the molding compound by mixing with organic peroxides. The cellulose short fibers may be fibrous and / or sheeted PVC W components and up to 60% by mass of powdered and / or globular cellulose products' and / or cellulose by-products, for example microcrystalline cellulose or ground paper waste.

Claims (4)

Pat ent pruch 1. Kurzfaeerverstärkte Polyolefinformmasse based on polyethylene and / or its copolymers or polypropylene and * cellulose short fibers, characterized in that the Polyolefinformmasse from 5 to 60% by weight, preferably 10 to 40 mass cellulose short fibers, based on the polyolefin content, and 0.1 up to 30% by mass, preferably 0.1 to 1.5% by mass, based on the cellulose short fiber content, of peroxides 2. short-fiber-reinforced polyolefin molding composition according to item 1, characterized in that the cellulose short fibers contain up to 75% by weight, preferably up to 30% to 60% by weight of fibrous and / or planar PVC / YZ components. 3 «short fiber-reinforced polyolefin molding composition according to item 1 and 2, characterized in that the molding composition contains up to 10% by mass of ethylene-vinyl acetate copolymer, based on the polynolefin content, 4 »Short fiber-reinforced polyolefin molding compound according to item 1 to 3, characterized in that the molding composition contains up to 60% by mass of powdered and / or globular cellulose products and / or cellulose waste products, for example microcrystalline cellulose or ground paper waste.