MXPA97001314A - Masses of molding of synthetic material with menordesga - Google Patents

Abstract

The molding compositions, which contain a thermoplastic material, at least one slip agent and at least one material in the form of fibers, have a high abrasion resistance together with high rigidity. A model mass contains, for example, a poly (oxymethylene), an ultra high molecular weight polyethylene as a slip agent, and glass fibers. The molding compounds are used for the production of sprockets, toothed racks, bearings and chain

Description

SYNTHETIC MATERIAL MOLDING MASSES WITH LESS WEAR A poly (oxymethylene) reinforced with glass fibers manifests a high wear. Surprisingly, it was found that the thermoplastic materials, which contain a slip agent (lubricant) and a reinforcing material in the form of fibers, exhibit a significantly lower abrasion wear and better stiffness than thermoplastic materials, which only contain a slip agent. Sliding or a material in the form of fibers. Accordingly, according to the invention, molding compositions containing a thermoplastic material, a slip agent and a material in the form of fibers. The thermoplastic materials are for example polyesters, polyamides, polycarbonates, polyolefins, poly (oxymethylene) and liquid crystalline polymers (LCP). Preferred thermoplastic materials are polyacetals, polyesters and polyamides. Polyacetals, especially poly (oxymethylene), include homopolymers and copolymers. Polyacetals are described in the bibliographical citation "Becker / Braun, Kunststoff Handbuch, Volume 3/1, Chapter 4 - Polyacetals, Cari Hanser Verlag München, 1992, pages 300-395", to which reference is made. Preferred polyesters are poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PET). Preferred polyamides are polyamide 66 and polyamide 46. Polyamides and polyesters are described, for example, in the work "Ullmann's encyclopedia of industrial Chemistry", compiler Barbara Elvers, volume A21, chapter "Polyamides" (pages 179-205) and chapter "Polyesters" (pages 227-251), VCH, Weinheim-Basel-Cambridge-Ne York 1992", to which reference is made.Sliding agents are additions that improve the sliding and abrasion behavior of synthetic materials. slip agents, for example, molybdenum disulfide, silicone oils, fatty alcohols, esters of fatty alcohols with dicarboxylic acids, fatty acid esters, fatty acids, fatty acid monoamides, fatty acid diamides (amides-waxes), soaps metals, esters of oligomeric fatty acids (complex esters of fatty acids), esters-acid-waxes, polyethylene polar waxes, apolar waxes of polyethylene, paraffins, polymers flu ores and polyolefins of ultra high molecular weight. Sliding agents are also certain combinations of different sliding agents (slip agents in combination). Slip agents are described in the work "Gáchter / Müller, Taschenbuch der Kunststoff-Additive, 3rd edition, Cari Hanser Verlag München editorial in 1994, pages 478-504", to which reference is made. Preferred glidants are poly (tetrafluoroethylene) (PTFE), ultra high molecular weight polyethylene (UHM), stearyl stearate and pentaerythritol tetrastearate. An especially preferred glidant is ultra high molecular weight polyethylene. The materials in the form of fibers or reinforcing materials are mineral fibers, glass fibers, modified glass fibers, filiform crystals, polymer fibers, carbon fibers and high modulus organic fibers. The modified glass fibers are in general glass fibers, which had been chemically treated, in order to improve the adherence of the glass fibers with the synthetic material. For the treatment of glass fibers, organic silanes are often used. The preferred materials in the form of fibers are modified and unmodified glass fibers. The molding compositions according to the invention contain, for example, from 50 to 90 percent by weight, preferably from 60 to 80 percent by weight, preferably from 5 to 20 percent by weight of a slip agent, and from 5 to 40 percent by weight. percent by weight, preferably from 10 to 30 percent by weight of a material in the form of fibers, the sum of the proportions being at most 100 percent by weight. The molding compositions can contain conventional fillers, such as clay, talc, clay, mica, glass spheres, zinc oxide, titanium dioxide, wollastonite as well as other usual additive materials and processing aids such as dyes, pigments, separating agents (de-molding), antioxidants and ultraviolet (UV) stabilizers. The proportion of these additions is usually in O to 50, preferably 5 to 40 parts by weight, per 100 parts by weight of the total amount. Molding compositions containing a polyacetal, at least one slip agent and at least one material in the form of fibers are preferred. Molding compositions containing a polyacetal, an ultra high molecular weight polyethylene or a PTFE, and at least one material in the form of fibers are particularly preferred. Especially advantageous is a molding compound, which contains a polyacetal, an ultra-high molecular weight polyethylene and unmodified or modified glass fibers. Such molding compositions are characterized by particularly high abrasion resistance and stiffness. The ultra high molecular weight polyethylene is used, for example, in the form of powders, in particular in the form of micro-powders. The powders generally have a mean grain diameter D50 in the range from 1 to 5,000 μm, preferably from 10 to 500 μm and particularly preferably from 10 to 150 μm. Modified or unmodified glass fibers generally have a nominal diameter in the range from 1 to 1,000 μm, preferably from 1 to 100 μm, and particularly preferably from 1 to 20 μm. Modified or unmodified glass fibers generally have an average fiber length in the range of 0.1 to 100 mm, preferably in the range of 1 to 100 mm and particularly preferably in the range of 5 to 20 mm.

The molding compositions according to the invention, especially the molding compositions containing a polyacetal, are especially suitable for the following uses: AUTOMOTIVE INDUSTRY: Sliding and functional parts in retractor systems of safety belts, gear wheels and functional parts, among other applications for the drive of windshield wipers and drive linkages, windshield wiper bearings, seat adjustment systems, window power propulsion systems , systems of regulation of mirrors and sliding roofs, MECHANICAL CONSTRUCTIONS IN GENERAL AND PRECISION WORK TECHNOLOGY: Conveyor chains, toothed rack and toothed wheels (among other applications, for drive elements), regulation mechanisms, bearing sleeves and functional parts (among other applications, for railway trains and funiculars).

FURNITURE INDUSTRY: Hinges (eg for cabinets, desk tables, friction bearing saddles, rollers and wear strips (eg, among other applications, for drawers, sliding doors).

SMALL SIZE APPLIANCES: Toothed wheels in the sector of transmissions in kitchen machines, meat grinders, hand mixers, crushers, juicers, citrus fruit squeezers, grain crushers and universal cutters.

WHITE SERIES APPLIANCES: Door hinges for dishwashers, washing machines and dryers (clothes), functional parts for belt tensioners in clothes dryers, individual parts for shock absorbers, washing machines, door brake housings in dishwashing machines , wheels for straps for clothes dryers.

ELECTRICAL TOOLS (PREFERABLY IN THE DOMESTIC WORKS SECTOR (DIY)): Toothed wheels for electric lawn care equipment, lawnmowers, scissors and herbal tilers, electric scissors wheels for gardener scissors and chain saws, as well as functional pieces in choppers (straw and fodder). Other applications are: Supporting saddles, functional parts for electric epilating devices, parts of nozzles for vacuum cleaners, functional parts for shavers, beard cutting machines, hair cutting machines, "Outsert" applications (rigid friction bearings) ).

EXAMPLES For Examples 1 to 3 and Comparative Examples A and B a trioxane copolymer with dioxolane with a melt index, MFR 190 / 2.16, of 2.5 g / 10 min (RHostaform C) was used. 2521). The copolymer was mixed with the following additive materials: PE-UHM micropowder, mean grain diameter 120 μm, viscosity index according to DIN 53 728-4 = 2,300 ml / g. Cut glass fibers, nominal diameter of the filaments approximately 13 μm, average length of the fibers approximately 4.5 mm.

The copolymer was mixed with the additives indicated in a slow-running mixer, and then fed into a twin screw extruder of the type ZSK 25 (Werner and Pfleiderer entity, Stuttgart, Federal Republic of Germany) and melted at a temperature of the mass of approximately 200 ° C and were brought to the form of a granulate. After drying in a drying oven with circulating air for eight hours at 120 ° C, the test specimens for the mechanical, thermal and tribological properties test were produced in an injection molding machine of type KM 90/210 B (entity Krauss Maffei, München, Federal Republic of Germany). The processing conditions were chosen in accordance with the recommendations of the standard regarding materials for poly (oxymethylene) ISO 9988-2. The tensile modulus of elasticity, according to ISO 527, parts 1 and 2, were measured. The hot form stability HDT / A, according to ISO 75, parts 1 and 2 Charpy impact toughness, according to ISO standard 179 leU.

Wear measurement: Abrasion was measured according to the test principle "pin on ring" = "spigot on ring" according to ISO / DIS 7148-2. On a rotating shaft, cylindrical specimens with a diameter of 12 mm are pressed on the basis of the technical material to be tested and the volume of wear on the specimens is determined as a function of time. The test conditions were as follows: Tree, steel technical material Diameter of the tree 65 mm Depth of roughness Rz 0.8 μm Load 3.1 N Sliding speed 136 m / min Duration of the experiment 60 h Table 1: Determination of the volume of the wear, of the modulus E in tension and of the stability of form in hot as well as of the tenacity to the impact Charpy Examples A B 1 2 3 POM copolymer by weight 74 90 80 70 60 Glass fibers% by weight 26 - 10 20 30 PE-UHMW% by weight - 10 10 10 10 Volume of wear mm3 32 1 2.8 3 3.5 Module E in traction ISO 527 N / mm2 9,000 2,200 4,000 6,500 8,900 Hot shape stability ISO 75 ° C 160 85 1 1 6 1 35 140 HDT / A Impact toughness Charpy ISO 179 mJ / mm2 30 50 32 24 12 For Examples 4 to 5 a trioxane copolymer was used with dioxolane having an MFR 190 / 2.16 fusion index of 9.5 g / 10 min (RHformform C 9021). The copolymer was mixed with the following additive materials.-PE-UHMW micropowders, mean grain diameter 120 μM, viscosity index according to DIN 53.728-4 = 2.300 ml / g Modified cut glass fibers, type RES03-TP33G ( Nippon Glas Fiber Co., Kromoricho Takachya, Japan), nominal diameter of the filaments approximately 10 μm, medium length of glass fibers are silanized and treated with a polyurethane. The test specimens for the mechanical, thermal and tribological properties were produced according to the same procedure and under the same processing conditions as in Examples 1 to 3 and Comparative Examples A and B.

They were measured: The modulus E in tension, according to the nori ** - * ^ ISO 527 parts 1 and 2. The shape stability in ca, HDT / A lens, according to ISO 75 parts 1 and 2. The wear measurement was carried out as described for Examples 1 to 3 and Comparative Examples A and B: Table 2: Determination of the volume of wear, of the modulus E in tension and of the shape stability in hot Examples 4 5 Copolymer of POM% in 85 69 Glass fibers weight 10 26 PE-UHMW% in 5 5 Volume of wear weight 1, 5 1, 9 Module E in traction ISO 527% in 4,400 8,800 Hot shape stability ISO 75 weight 1 55 162 HDT / A mm3 N / mm2 ° C

Claims (7)

NOVELTY OF THE INVENTION CLAIMS

1. - Molding masses containing a thermoplastic material, at least one slip agent and at least one material in the form of fibers.

2. Molding composition according to claim 1, characterized in that a polyester, a polyamine, a polyolefin or a polyacetal is used as the thermoplastic material.

3. Molding compound according to claim 1 or 2, characterized in that a fatty amine, an ester of montanic acid, a ester of partially saponified montanic acid, a stearyl stearate, pentaerythritol tetrastearate, PTFE or polyethylene are used as the slip agent. of ultra-high molecular weight. .

Molding composition according to one or more of claims 1 to 3, characterized in that modified glass fibers, carbon fibers or polymeric fibers are used as the material in the form of fibers.

Molding composition according to one or more of claims 1 to 4, the molding composition being characterized in that it contains from 50 to 90, preferably from 60 to 80, parts by weight of the thermoplastic material.

6. - molding compound according to one or more of claims 1 to 5, the molding compound is characterized in that it contains from 5 to 30, preferably from 5 to 20 parts by weight of a slip agent.

7. Molding composition according to one or more of claims 1 to 6, the molding composition being characterized in that it contains from 5 to 40, preferably from 10 to 30, parts by weight of the material in the form of fibers. 8. - Use of the molding compound according to claims 1 to 7, for the manufacture of molded parts, especially sprockets, toothed racks, bearing bearings, drive elements, rollers, chains and sliding elements.