CS255455B1 - Mixture for continuous dyeing of polystyrene materials - Google Patents

Abstract

Mixture for continuous dyeing of polystyrene mass produced by the block technology The white shade is prepared using special premixes. It is a mixture composed of 50 wt. titanium dioxide rutile type 1 to 10 wt. parts of stearin, 0.5 to 5 wt. internal lubricant parts and z 44 to 100 wt. of polystyrene in the mold 0.1 to 0.5 mm diameter beads.

Description

(54) A mixture for continuous dyeing of polystyrene compositions

The mixture for continuous dyeing of polystyrene materials produced by block technology to white tint is prepared using a special premix. It is a mixture of 50 wt. parts of rutile type titanium dioxide of 1 to 10 wt. 0.5 parts to 5 wt. parts of internal lubricant and from 44 to 100 wt. parts of polystyrene in the form of beads with a diameter of 0.1 to 0.5 mm.

BACKGROUND OF THE INVENTION The present invention relates to a blend for the continuous dyeing of polystyrene compositions to a white shade by block polymerization.

In the production of polystyrene materials by block polymerization, polystyrene in the form of a melt is continuously withdrawn from the line. The finished polymer is generally granulated in the form of non-colored beads.

However, continuous in-line dyeing processes (IN LINE) are also known, where the master is added either to melt drawn through a screw feeder such as tower technology or pumped into a homogenization extruder in a modern block technology.

For IN LINE staining, direct dosing of dye or pigment cannot be used.

It is known to use granulated starch, which is produced by extrusion of concentrated mixtures. In the manufacture of starch in block technologies, mixing of the granulate of the prepared and powdered pigment in the present case with titanium dioxide is a major problem.

Mixed mixtures are scattered due to completely different dispersions and different polymer and pigment specific weights. The inhomogeneous mixture, due to the high concentration of inorganic pigment, causes considerable difficulty in extruding the starch.

Separated portions of the mixture containing more than 50 wt. pigment, cannot be extruded.

Solving the problem requires complicated machinery. All containers for the blend must be thoroughly mixed, or a low titanium dioxide concentration in the grate must be used, which increases the cost of the grate line.

These disadvantages do not have a mixture for the continuous coloring of polystyrene compositions to a white shade containing 50 wt. parts of titanium dioxide of the rutile type, 1 to 10 wt. 0.5 parts to 5 wt. parts of the internal lubricant to which, according to the invention, in addition 44 to 100 wt. The mixture prepared in this way does not separate spontaneously, it can be prepared on a conventional quick mixer with a significantly lower energy intensity.

Conventionally manufactured polystyrene prepared by any technology in the form of dry beads can be used to prepare the mixture.

For example, calcium, optionally powder or ground polyethylene having a molecular weight of 20,000 to 100,000 may be used as the internal lubricant.

Dispersants may also be added to the mixture.

Example 1

A mix consisting of 50 nm was prepared in a mixer. parts of titanium white, 44 wt. parts by weight of granulated block tough polystyrene, 5 wt. parts of stearin and 1 wt. % of calcium stearate. The mixture was discharged into the intermediate tank from where it was continuously dosed. to the block tough polystyrene line. In the intermediate tank and in the metering device, the pigment and polystyrene were separated due to different specific weights and different dispersities.

The coloring of the polymer was inhomogeneous and clogged parts of the apparatus.

Example 2

The invention was followed.

A mixture consisting of 50 wt. parts of titanium dioxide of commercially available type, 44 wt. parts by weight of injection-molded polystyrene in the form of beads prepared by block polymerization suspension *, 5 wt. parts of stearin and 1 wt. % of calcium stearate. After mixing in a Henschel quick mixer, the finished mixture was fed continuously into the lystyrene block line. The mixture was well absorbent and there was no separation at dosing.

3 wt. parts of the mixture per 100 wt. parts of extruded melt of tough block polystyrene. Bodies were sprayed from the obtained granulate for coloristic evaluation.

The coloring was homogeneous.

X)

Block suspension polymerization The block suspension polymerization polymerization cycle consists of two main phases: block prepolymerization of styrene in the presence of dissolved polybutadiene rubber, in which, in addition to styrene homopolymerization, grafting to the rubber chains takes place. The block polymerization is generally carried out as thermal.

Once the desired viscosity of the prepolymer has been reached, the aqueous phase containing the slurry stabilizer is added, the initiators are added and the whole process is continued as slurry polymerization to facilitate heat dissipation.

Example 3

A 50 wt. parts of titanium dioxide of the rutile type,

100 wt. parts of injection molded beaded polystyrene, 5 wt. parts of stearin and 1 wt. part of powdered polyethylene.

The mixture was stirred for 300 seconds. The ready-to-mix mixture was used for continuous dyeing of polystyrene melt drawn from the polystyrene block line.

3 wt. parts per 100 parts polystyrene block.

The obtained white shade of the block-like toughened polycarbonate corresponded to the 4th degree of the gray scale.

Example 4

A mixture was prepared in a similar manner to Example 3, except that 50 wt. parts of titanium white of the rutile type were dosed with 65 wt. parts of standard polystyrene bead, 9 wt. parts of stearin and 0.7 wt. % of calcium stearate.

The mixture was easy to pour and its dosage did not cause any problems. 2.5 wt. parts of the mixture per 100 wt. melt parts drawn from the polystyrene block line.

The white shade obtained was homogeneous.

Example 5

As in Example 3, a mixture of the following composition was prepared: 50 wt. parts of titanium white, 80 wt. parts of standard pearl polystyrene, 1 wt. stearin and 5 wt. parts of calcium stearate.

After mixing in a high-speed mixer, the well-flowable mixture was continuously metered into the block tough polystyrene line.

3 wt. parts of the mixture per 100 wt. parts of polystyrene melt.

2-55455

The melt extrusion was pulsation-free, and the obtained block-resistant polystyrene was homogeneously colored.

Claims (1)

SUBJECT OF THE INVENTION Mixture for continuous dyeing of polystyrene materials produced by block technology to white tint, consisting of 50 wt. parts of titanium white of the rutile type, 1 to 10 wt. 0.5 parts to 5 wt. parts of an internal lubricant, characterized in that it additionally contains 44 to 100 wt. parts of polystyrene in the form of a bead polymer with a bead diameter of 0.1 to 0.5 mm.