DE2924063A1 - Plastomer mfr. with improved physical properties - by stretch deformation in rolling mill gap at raised temp. - Google Patents

Abstract

Slabs, plates, profiles and other sections, made of a plastomer are passed through the gap between pairs of rolls which reduces their cross-section by a combined compressive and shear stress. A sandwich type of structuring is produced thereby, with a grain orientation which is governed by the process temperature, velocity and friction of the rolls, and by the set gap width. To achieve permanent compressive stretch deformation in amorphous plastomers, the temperature is held below the glazing temperature, and in the case of partly crystalline plastomers the crystallite fusion temperature is the upper temperature threshold. This imparts to plastomers improved properties, specially as regards flexural rigidity, without having to add reinforcement, for example, by glass fibres. The complex machinery, required for biaxial stretch deformation of plastomers, is saved and standard rolling mills can be used.

Description

Description of the invention for patent application

Process for the production of panels, Frofilen and the like. Share out Plastomers with high strength, in particular flexural rigidity through compression stretching The invention relates to a method for producing plastomer sheets and profiles and similar Parts with better mechanical properties than the previous ones Process manufactured parts of this kind.

The improvement of the properties takes place in this process by the introduction of orientations in the preformed plates, profiles and similar. Plastomer parts either directly after manufacture, e.g.

after calendering or extrusion, or in a separate operation, in a calender, rolling mill, press or similar. and not by adding reinforcing materials, e.g. 3. Fibers.

The application of the invention makes it possible in plastic constructions Particularly stressed areas made of battens, profiles oriented by pressure stretching and similar To create parts and thus the usual reinforcements, e.g. Encore of glass fibers in the plastomer, application of GRP layers or through use particularly stiffening constructions to save.

State of the art The introduction of stretching in elastomer materials takes place according to different processes: fibers are stretched by tension after shaping, Films are oriented by mono-axial or biaxial stretching (Lit. H.Käufer, Kunststoffe als Material, Vogel Verlag, Würzburg, 1974) The application of pressure by a The press also leads to orientations in the material (Lit. H.Käufer, G.Arnold, Kuffststoffe 67 (1977), p. 457-460, H. Buyer, P.Kristukat, Kunststoffe 69 (1979), p. 89 - 94) The monoaxial tensile stretching brings improvements in the properties in the direction of tension, transversely in addition, the mechanical values decrease or remain the same.

The biaxial tensile stretching requires complicated devices (clip chains) that mechanical engineering very much Thicker when stretching Plates, profiles and similar Sharing there is a risk that the products will tear.

Compression stretching in presses or injection molding machines is discontinuous Process and effects the shaping in the press or injection molding machine (lit.

Patent application P 28 56 580.2, Germany) For pressure stretching the already specified part shape, e.g. panels, profiles and similar. Share, that means that Only limited lengths can be oriented in one operation, if correct Controlling the process, however, achieves the consolidation structures according to the invention will.

The nip of a calender or rolling mill acts on the other hand a continuous plastomer part like a continuous face Invention was therefore the solution to the problem, the calender or a rolling mill as a continuous Press for the production of pressure-stretched panels, profiles and similar. Share with better ones To make optimal use of properties.

Solution to the Problem According to the invention, this problem is solved by that prefabricated panels, profiles and similar. Parts whose thickness is greater than the set one Nip and larger than the final desired wall thickness of the end product is to be sent through the nip.

In order to obtain permanent compression stretching in the plastomer, the Temperatures of the rollers and the plates, profiles and the like. Parts in amorphous plastomers below the glass transition temperature and, in the case of partially crystalline plastomers, below the Crystallite melting point as the respective upper limit temperature.

From the lower limit, the temperature is the pressure stretching is carried out, in the application the temperature up to which the, by pressure stretching The orientations that have been introduced are retained thermoset.

However, the higher the pressure-stretching temperature from an application point of view Reasons must be chosen, the lower the producible and thus property-improving Orientations in the respective part.

The gap width is now chosen so that the semifinished product through the printing and shear stress in the nip is plastically deformed and thus oriented The speed of the rollers determines the relationship between pressure and shear stress, low speed means high compressive stress and low shear in the plastomer, high speed means additional pressure with the same compressive stress a high shear of the plastomer which depends on the design.

The friction of the rollers has a decisive influence on the inner one Structure and thus on the properties of the pressure-stretched panels, profiles and similar Parts. Under the electron microscope prove that structurally a sandwich-like structure over the thickness of the pressure-stretched plates, profiles and similar Sketch 1 Sketch 1 An inner core (1) is structured differently oriented outer layers (2), (3). The thickness of the individual layers and their position in relation to one another is determined by the temperature, roller speed and roller gap The temperature is decisive for the temperature that remains in the end product Orientations: The roller speed determines the pressure action time on the panel profiles and similar parts.

The width of the nip determines the one acting on the part Pressure and the thickness of the final product.

The friction determines the position of the individual layers.

Without friction, they are symmetrical about the center of the thickness of the part Properties of the end product are thus also symmetrical across the thickness of the part. With Friction shifts the layers and thus also the properties over the Thickness of the end product. With this a compression-stretched sheet, a profile and a similar Part are generated according to the respective application requirements.

The advantages that can be achieved with the invention are: 1) the complicated structure of a biaxial stretching system is avoided, since a continuous Process for pressure stretching of plates, profiles and the like. Share developed is, 2) due to the improved material properties material savings or at better performance properties can be achieved with the same amount of material, 3) in contrast for monoaxial stretching, despite the high degree of stretching, no tendency to splice transversely to the direction of stretching occurs, 4) a directed sandwich-like in one operation Structure in the end product is created, the decisive layer thicknesses through Intervention on the calender or rolling mill can be adapted to the later application, 5) the temperature at which the pressure stretching is carried out is simultaneous the highest application temperature, 6) the roller speed, together with the gap width, the amount of pressure stretching in the end product is determined, 7) with the friction, the position of the sandwich-like structures and thus the properties of the end product are determined, 8) normal production machines are used, 9) the plates, profiles and similar. Parts after pressure stretching are heated up thus reshape without further heating, e.g. deep-draw, let.

Claims (6)

Claims for registration with the title: Method of production of plates, profiles and similar Plastomer parts with high strength, especially Flexural rigidity through compression stretching main claim The process is thereby characterized that in plastomer plates, profiles and the like. Divide by simultaneous Compressive and shear stress at certain temperatures. Orientation areas be introduced with a sandwich-like structure and thus better properties can be achieved. Dependent claims 1) The process for the production of pressure-stretched Plates, profiles and similar Sharing is characterized by the fact that a given semi-finished product is continuously stretched by pressure, the desired orientations through the Process temperatures, Roller speeds and friction and the set gap width can be specified. 2) The method is characterized in that the so pressure-stretched Plates, profiles and similar Parts in use up to the temperature at which they will be pressure stretched are dimensionally stable. 3) The method is characterized in that the semi-finished product after its production in the cooling phase also reaches the temperature at which the pressure stretching brings the most optimal properties for the respective application after the primary shaping of the semifinished product, without further heating of the semifinished product, pressure stretching possible. 4) The method is characterized in that the pressure stretching to a heating of the plates, profiles and similar. Parts leads, # o that directly after the compression stretching the plates, profiles and the like. Parts formed, e.g. can be deep drawn without another Warming must take place. 5) The method is characterized in that the pressure-stretched Sheets, profiles and similar parts show no tendency to splice across the direction of stretching. 6) The method is characterized in that for the production of ? battens, #rofilen and similar. Parts made from plastomers with high strength, in particular Flexural rigidity through compression stretching conventional primary and forming machines can be used.