CS244968B1 - Continual method and apparatus producing spun-dyed polymeres - Google Patents

Abstract

The solution relates to a continuous production process synthetic fibers or other shaped fibers plastic products dyed in mass in the production process. Coloring in the mass is dispersed by dispersing continuously! of pigments at the beginning of the worm depending on the number of workers forming sites, with the required polymer to fill the dispersion with the bulk of the screw. The invention can be used to produce fibers, foils, tubes, etc., which are being prepared in a continuous manner.

Description

SUMMARY OF THE INVENTION The present invention provides a process and apparatus for continuously dyeing polymers in a mass.

Synthetic fibers, foils, or other continuously prepared products, are produced and dyed in the mass most often on worm spinning machines. In the extruder, the material is melted and homogenized with the pigment dispersion and extruded directly or through a branch to the individual forming sites. The color dispersion is added in different ways, either used as a mixture of granules with the base polymer, or coated with the base polymer granulate, or dosed in liquid form (melt) into the polymer melt, or they are difficult to Each of these methods has its advantages and disadvantages and is applied according to the color intensity, the process equipment used and the color dispersion properties.

The injection dyeing method is demanding on the homogenizer because homogenization is carried out at low shear forces. The thermal stress of the pigments in the case of solid color dispersions varies depending on the amount of dispersions dispensed and is great especially when dispensing smaller quantities of concentrates due to prolonged concentrate retention in the melter. The device is also demanding for regulation, which is to ensure constant conditions of melting, dosing and homogenization. The advantage, however, is the possibility of modifying the rheological properties of the polymer by its thermal degradation without the presence of a pigment which would not tolerate these conditions.

A certain quality of ready-to-melt dispersions is required for coating the granulate, which may adversely affect some color fastnesses, particularly in abrasion.

When using a mixture of granular polymers and dispersions, the problem of uniformity of coloration is encountered both because of the separation of the concentrates from the polymer and because of the high ratios between the polymer granules and the dispersion.

The problem of uniformity of coloration is particularly pronounced when dyeing to a particular shade with a mixture of color dispersions of the base shades.

We have found that the present invention will eliminate or substantially reduce the reported drawbacks. The method is based on the fact that the color dispersions or their surface-treated antistatic mixture is continuously fed into the first zone of the extruder and a polymer is fed into the subsequent zone of the extruder, which fills the free space between the cotter and the working roller housing. They are continuously mixed in the extruder and, after melting, homogenizing their melts not only transversely to the axis of the extruder spindle, but also along the axis of the extruder by producing a high backflow.

The device for this purpose consists of a multi-zone screw-melting device 10, in a first zone 11 provided with a dispersion 20 of color dispersion, in a second zone 12 a feed polymer 13, the output of the dispensing device 20 being controlled by the operation sensor 100 of each processing station 101. may be indicated by a pressure sensor downstream of the metering pump, a contact switch operated by the metering pump cut-off lever, a tachometer, and the like. The working cylinder of the apparatus 10 consists of a heated working cylinder 15 and a working cylinder screw 16 and consists of a melting and compression zone and a mixing zone consisting either of a spindle with intermittent threads or a spindle with greater freedom or spindle provided with spreading or braking elements.

The dosing of the individual concentrates or of the mixture of concentrates is carried out either by volume or, for more precise proportions, by mass dispensers. If a mixture of concentrates is used, this should be treated antistatically by adding a small amount, e.g. 0.05% of a suitable liquid antistatic agent when preparing the mixture in a homogenizer. This prevents separation of the individual components.

At higher proportions of the individual concentrates forming the mixture prepared to achieve the desired shade, homogenization of the melt also along the axis is required. This is achieved in various ways, e.g. by providing high backflow by increasing resistance at the end of the extruder, or by grooves in the threads (by threading) or by increasing the play of the screw in the work roll housing or by other suitable means of adjusting the extruder spindle.

In this way, the melt is homogeneous and dispersive, and overall the production equipment is simplified, since metering pumps will not be needed to dispense and maintain the dispersion and base polymer ratios. The necessary pressure for conveying the melt to the individual molding sites is exerted by the extruder speed as a function of the pressure upstream of the molding site, respectively. distribution to the forming points.

Example 1

The granulated 15% Red 144 pigment concentrate is metered into the hopper of the dyeing dispersions of the helical melter at 5.5 kg / h by a twin screw dispenser. Polypropylene IT 20 g / 10 min. it enters the extruder through a second hopper disposed in a further, still cooled part of the extruder in an amount supplementing the free space of the spindle screw. The spindle speed is controlled by the pressure in the distribution branch, which is kept at a constant value of 5 MPa. In the extruder, the con244 centrate is mixed with the polymer, melted at temperatures of the individual heating zones of 220 ° C, 240 ^° C and 260 ° C, and dispersed. The spindle presses the homogeneous melt through a continuously operating filter 6 'to the bottom strand to the twelve spinning stations where the melt is dosed and pumped through the spinning blocks having a fiber content of 6.5 kg / hour for the spinning station. By disconnecting the spinning station in case of replacing the spinning block or other forced shutdown, the contact sensor coupled to the pump lever being turned off gives a pulse to the microprocessor to reduce the dispersion dosing by 1/12. The fibers produced are uniformly colored.

Example 2

A 1: 4: 1 mixture of powdered pre-dispersed pigments of C.I. Red 144, Yellow 83, Black 7 in a 1: 4: 1 ratio is metered into the void space of the spindle formed by damming the polymer feed hopper at 3.8 kg / h. The second part of the hopper is supplemented with a polypropylene screw. The mixture is further processed to the fibers of Example 1.

Example 3

The agglomerated dispersion, containing a mixture of Blue 15: 1 (C.I.) and Black 7 pigments, is metered into a extruder using a spiral feeder similar to Example 1 and processed into fibers.

Claims (2)

A continuous process for coloring polymers in a mass in which a color dispersion is dosed and the base polymer is fed to a threaded melter, characterized in that the color dispersion is dispensed into the first zone of the melter and the space to be processed is filled. the amount of color dispersion dispensed is dependent upon the amount of colored polymer to be drawn to form fibers, foils or other shaped articles. INVENTION It An apparatus for continuous dyeing of polymers in a mass, comprising a melter having a feed of a processed polymer and a dispersion for a color dispersion, characterized in that the color dispersion dispenser is connected to the first zone (11) of the melter (10) and the feed is into a subsequent second zone (12), wherein the power of the dosing device is controlled by means of a sensor (100J) of the operation of the individual processing sites.