CS211439B1 - A method for producing surface-embossed sheet plastics - Google Patents

Abstract

The purpose of the invention is a method for producing surface-patterned plastic sheet materials. The essence of the invention lies in embossing a textile layer of the desired pattern into the surface of a plastic sheet material, whereby the textile layer remains embedded in the plastic surface for a maximum of 90% of its thickness during its subsequent passage through areas of plastic and viscoelastic flow, and after cooling, and thus the transition of the plastic sheet material to a solid state, but not at a temperature lower than 10 °C, the layers are separated from each other by tension. The sheet materials produced by the method of the invention can be used, for example, as structural materials for lampshades, tablecloths, curtains, for haberdashery and decorative purposes.

Description

The invention solves a process for the production of surface-embossed sheet materials of plastics.

A number of methods for producing sheet materials from plastics and obtaining densene (indentation, spatial pattern) on their surface are known.

A conventional method of embossing flat materials by means of a embossing roller provided with a negative pattern is transmitted to it by the pressure of a mollet onto which the pattern has been made by hand engraving. The tread roller, together with the opposite rubber-lined roller, forms a pair in which the plastic sheet material is provided with a design in the slot. In principle, two procedures are recognized.

Hot and cold roller design. In hot roll embossing, the sheet material enters the slot and is compressed by the pressure exerted by the roll. The plastic sheet material heats up and releases the material tension in part because it accepts the pattern configuration, in part due to molecular shifts.

The stress releases until the contact is terminated, at which point the sheet material has a temperature approximately equal to that of the tread roller, so that upon release of the material from the tread roller, the web may exhibit flow under surface forces and supported by residual stresses. The extent of this flow depends on the conditions, but in general it can be assumed that the depth of the indentation, the tread in the material, is about half the depth of the dézene. war.

The cold roll method requires that the surface temperature of the sheet material be so high before it enters the slot that the material can be deformed in the plastic state before freezing. When properly executed, the material leaves the slot at a temperature below the flow temperature. However, this is not always achieved under operating conditions.

It is also described that the desired effect can be achieved by a method of inserting a suitable liner, e.g., fabric, plastic film, between the embossing rollers and the surface of the patterned sheet material. Here, the liner encircles the steel cylinder, after leaving the cylinder, it is wound up or returns in the form of a closed strip in a continuous process.

According to MS. No. 152 078, the surface of plastics materials is also treated by applying a thin permeable plastic layer to the surface of the base material layer by means of a transfer film and then joining the applied plastic layer to the base material by applying a tensile roller pressure at elevated temperature. The transfer film used does not serve to create a tread, but to transfer a surface film and protect the tread roller. The need for a tread roller remains.

For very deep treads, vacuum treading is recommended.

The treading roller processes have a negative side in the high labor and demandingness required to produce a treading roller resulting in the requirements for a large series of products.

These special treading machines are either installed at the end of the production lines or work independently. The intermediate insert procedure is suitable for smaller test runs where it would not be economical to purchase an expensive tread roller. The deterioration in heat transfer is adversely affected by the auxiliary insert wall, which is particularly important in the cold cylinder method, which requires intensive cooling in a very short contact time of the order of a few seconds.

An analogous process of continuous embossing using a roller is the discontinuous embossing of sheets, formats using a patterned plate in presses.

The above-mentioned drawbacks substantially reduce the process according to the invention, characterized in that a textile layer of the desired spatial pattern is pressed into the surface of the plastic sheet material, while the textile layer remains embedded in the plastic surface at most 90% of its thickness. The plastic layers and the viscoelastic flow, and after cooling, and thus the transition of the sheet material from the plastic to the solid state, but not below 10 ° C, the layers are separated by tension.

• The plastic sheeting is provided with a textile layer during or after production by known manufacturing processes, such as lamination by roller, brush or press. After the plastic has cooled, the textile layer is separated and a negative tread pattern is formed on the separated side of the surface of the plastic sheet. In this case, the tensile strength of the two separated layers of given thicknesses is greater than the cohesion of the two layers relative to the uniform band width and the point, respectively. melting points of plastic sheet material; plastic is lower than the point, ev. melting points of the constituents of the textile layer or less than at least the melting point of one of the constituents.

The textile layer may be of technical or consumer original purpose, of organic or inorganic origin, or of a mixture thereof, fabric, knitted fabric or nonwoven fabric; reinforced with fabric or knitted fabric. Weave, fineness of fibers, spatial surface treatment of textile layer determining the tread pattern of plastic material.

The sheet material of plastics, or plastics, may be either single-layer or two-layer and multi-layer, one or more layers of which may be formed of textile, paper, metal, wood. It may be in the form of an endless belt or finite dimensions. In terms of thickness, these can be foils or boards, in terms of construction also plastic skins, laminated foils of various types, boards, coated foils or boards of metal, wood, paper, etc.

The production of laminated sheet materials can be carried out on known plastic sheeting machines and devices for laminating them with a textile layer (extrusion lines, rolling lines, presses, etc.) in a manner similar to that preferably lower temperatures, ev, and pressure can be used. during lamination. Tension separation is carried out either on a separate device consisting of one winding and two winding stations, or the pressing of the textile layer and the separation can be carried out on one device, with ev. using an endless textile belt. The separated textile layer can be ironed before use.

The described process for producing surface-embossed sheet materials of plastics has some advantages over known processes.

It allows very flexible reaction to fashion requirements, especially in small-lot production, it does not require special expensive treading equipment and single-purpose treading rollers. The indisputable advantage of the described method is economic undemandingness. Unlike the existing processes, where the treading roller is single-purpose, the textile layer after repeated use for the treading purpose can be subsequently used either as a material for the production of plastic laminate with textile, e. otherwise as a textile material. The multiplicity of reuse of the textile layer depends on the design and finish of the textile layer, the composition and surface treatment of the fibers, the plastic sheet material, the lamination pressure and temperature, and the separation temperature.

Since the patterning textile layer remains in the surface of the plastics sheet as it passes through the areas in which the plastics flow and is separated when the plastics is in a rigid state, the contact time being in the order of minutes, it cannot subsequently occur in the tread formed to the flow.

Claims (1)

Example A 1.0 mm thick film was produced from high-pressure polyethylene (density 921 kg/m^, melt index 2 g/10 min and viscosity 3,000 Pa . s/190 °C) on a single-screw extruder with a 60 mm screw diameter and a flat adjustable slot. The textile layer was pressed into the slot between the lower and middle rollers of a three-roller pull-off calibration and laminating machine. The fabric used was 45% polyamide, 55% viscose. Head temperature 185 °C, rollers 35 °C. After the laminate had cooled, the layers were separated at a plastic temperature of 40 °C. The following values were found: cohesion of the layers in the longitudinal direction across the tensile strength of the PE film in the longitudinal direction. across the tensile strength of the fabric along the warp along the weft ČSN 64 0730 14.22 N,'ρο after conversion 710.98 N/m Σε 14.22 N, after conversion 710.98 N/m width ČSN 64 0720 10.297 kN/m width 10.101 kN/m width * CSN 80 0815 357.94 N/5 cm, after conversion 7.159 kN/m 328.52 N/5 cm, after conversion 6.570 kN/m The obtained patterned foil was suitable, for example, for lampshades. Example 2 Procedure according to example 1. Fabric containing 100% viscose was used for lamination. The following values were found: layer cohesion along the direction across tensile strength of PE film in the direction across tensile strength of fabric along the warp along the weft Example 3 ČSN 64 0730 0.98 N, after conversion 49.03 N/m sulfur 1.96 N, after conversion 98.07 N/m ČSN 64 0720 9.611 kN/m 10.101 kN/m CSN 80 0815 220.64 N/5 cm, after conversion 4.413 kN/m 122.58 N/5 cm, after conversion 2.452 kN/m width Procedure according to example 1, fabric with a composition of 35% cotton, 65% ^PES was used. The following values were found: layer cohesion ČSN 64 0730 in the direction along 13.73 N, after conversion 686.47 N/m across 14.71 N, after conversion 735.50 N/m tensile strength of PE foil CSN 54 0720' in the direction along 9.611 kN/m e.g. no 10.003 kN/m tensile strength of fabric according to the outline 397.17 N/5 cm, converted to 7.943 kN/m Sulfur after weft 186.33 N/5 Cm, after conversion 3.727 kN/m width Example 4 A 1.0 mm thick film was produced from polypropylene (density at 23 °C 900 to 910 kg/m ³ melt index 0.7 g/10 min) on the equipment described in Example 1, laminated with glass fabric (with a basis weight of 119 g/m and a thickness of 0.208 mm) at temperatures of the draw-off and laminating rolls of 40 °C.