CS276953B6 - master batch for dyeing polyestyrene plastics with improved dispersing power - Google Patents

Abstract

Premix for dyeing polystyrene plastics with improved dispersibility organic dye or pigment, polyethylene, mixtures of mono-, di- and triglycerides fatty acids, sodium salts of dodecylbenzenesulfonic acid and polystyrene plastic. The composition exhibits increased dispersibility pigments, the processing takes place to break up pigment aggregates more easily particles, which is accompanied by an increase pigment coverage, by reducing permeability light and improving gloss

Description

The invention relates to a premix for dyeing polystyrene plastics. The premix provides improved dispersibility of the dye in the base polymeric substrate while increasing the gloss of the moldings and maintaining good toughness.

By polystyrene plastics are meant polyvinyl aromatic compositions in the chain of which the structural building blocks -CH 2 -C 4 -X are repeated, where X is aryl. We also include tough polyvinylaromatic materials as polyvinyl materials. A tough polyvinyl aromatic composition is a polystyrene which contains an unsaturated elastomer in an amount of 1 to 15% by weight as a modifying component.

The following are used for coloring plastics, including polystyrene materials:.

- soluble dyes (organic type),

- insoluble dyes - pigments (usually inorganic but also organic compounds),

- special additives (metal powders and the like).

In technical practice, the introduction of these additives is usually not carried out by direct dosing into the polymeric substrate, but in two technological stages in such a way that a colored premix is prepared, which is dosed into the polymeric material in the next step. The premix is generally a dispersion of a pure dye in a polymeric carrier which further contains a plasticizer and other additives. It is most important for the premix to achieve optimal dispersibility of the dye or pigment. Some pigments, especially red ones, are characterized by a high ability to form aggregates of pigment particles which are difficult to disperse during conventional processing on conventional extruders or injection molding machines. These aggregates then form a strongly diffusely reflective and optically rough surface on the surface of the moldings, which is manifested by the variable intensity of the reflected light. There is a specular effect, when the intensity of the gloss changes from point to point, there is a rapid deterioration in the appearance of the products. This negative phenomenon is often accompanied by the formation of so-called flow paths on the surface of moldings, which degrade the appearance properties of products. Uneven dispersion of the dye leads to a decrease in the strength characteristics of the moldings, where the aggregates act as stress concentrators in the polymer matrix and contribute to the initiation and growth of cracks.

From a morphological point of view, dyes or pigments consist of:

-the smallest particles of pigments,

-aggregates,

-agglomerates, -floculates.

It is known that optimal dispersion is achieved by a suitable assembly of machinery, the choice of screws, static installations in the plastic zone of the extruders, pre-mixing of mixers, high-speed mixers and the like. It is also known that dispersion can be positively influenced by the addition of so-called dispersing additives. '^;

Classification of the degree of dispersibility is experimentally demanding. For transparent materials, such as standard polystyrene, a method of measuring light transmittance can be used, usually on the photometric principle. Light microscopy in combination with phase contrast, scanning and transmission electron microscopy, contact X-ray micrography, and the like can be used to evaluate the degree of dispersion of elasticity in tough polyvinyl aromatic materials, such as tough polystyrene. For rapid evaluation of the quality of dispersion, the method of microscopic evaluation in transmitted light, where the preparation is a thin film prepared from the evaluated material, proved to be effective. Using this method, it was possible to monitor the level of pigment dispersion in the dyeing of polystyrene plastics, including the effect of the composition of the premix on the degree of homogeneity of dispersion of the dye in the polymer matrix.

Insufficient level of dispersion is manifested by the formation of aggregates, specular effect, in extreme cases then the formation of veils on the surface of moldings. The uneven degree of dispersion has a negative impact on the quality of the resulting color shade, its brilliance, opacity, or transparency. The dye agglomerates act in the polymer matrix as failure centers with a negative impact on the physico-mechanical properties of the final product.

These disadvantages are eliminated by a premix for dyeing polystyrene plastics in that it consists of 10 to 15 parts of organic. dye or inorganic pigment on a polymeric support, from 0.5 to 8 wt.%, polyethylene with a melt index of 10 to 25 g / 10 min, from 0.005 to 0.5 wt. parts of a mixture of mono-di and tri-glycerides of fatty acids, from 0.00005 to 0.005 by weight, parts of the sodium salt of dodecylbenzenesulfonic acid and a polystyrene polymer made up to 100 parts by weight, of a premix. The composition may further contain other conventional additives such as antioxidants, lubricants, flame retardants, toughness modifiers and the like.

The composition according to the invention shows an increased dispersibility of the pigments, during further processing the aggregates of the pigment particles are more easily disrupted, which is accompanied by an increase in the opacity of the pigment, a decrease in light transmission and an improvement in gloss. The increased dispersion using said premix can be explained by the interaction of the composite additives with the dodecylbenzenesulfonic acid salt.

The composition according to the invention shows a markedly improved dispersion on microscopic evaluation, better homogeneity for staining is achieved. The mixture is easy to handle and shows good transportability. When using the mixture according to the invention, it is possible to use an organic dye or, if appropriate, inorganic pigments with a lower opacity. Their negative impact on the dyeability is completely compensated by the perfect dispersion according to the invention.

The advantages of the mixture are documented by the following examples.

Example 1

A pigmented dye (hereinafter referred to as red dye) consisting of three components was used for dyeing polystyrene to a red tint:

a) red perylene pigments, b) pigments based on metal titanates, c) resinole orange in a premix with the composition:

- polystyrene,

- color concentrate,

- polyethylene,

- Polynol A,

- sodium dodecylbenzenesulphonate.

The red dye was mixed with other ingredients of the recipe in a high-speed mixer (an overview of the composition is given in Table 1). The premix produced was metered into a slow-running mixer in such a proportion that the red dye content was always 1% of the final mixture. The mixture was homogenized by extrusion on an extrusion line under the conditions:

- temperature under the hopper 160 ° C,

- plastic zone temperature 185 ° C,

- extruder head temperature 220 ° C.

The properties of the obtained granulate are given in Table 2.

Characteristics of raw materials used:

- standard polystyrene pearl d medium 0.42 mm melt index 15.7 g / 10 min

- block tough polystyrene bulk density 550 kg / m ³ melt index 3.8 g / 10 min

- tough polystyrene pearl d medium 0,34 mm.

melt index 3.7 g / 10 min

- Polynol A

White to slightly yellowish substance in the form of a powder, melting point min. 65 ° C, iodine number max. 5. It contains at least 90% fatty acid monoglycerides, approx. 5% diglycerides, approx. 1% triglycerides, max. 3% free glycerol and max. 1% free fatty acids.

- Polyethylene

Colored powder, grain size ranges between 30 to 500 μm bulk density 300 to 350 kg / m ³ melt index 17 g / 10 min specific weight 915 to 918 kg / m ³ molecular weight 150 to 250 kg / mol

- Sodium dodecylbenzenesulphonate

Slightly yellowish powder or flakes, active ingredient content 92.5% by weight, slightly hygroscopic character.

Table 1

Component b units standard stand.PS o s t u p HPS pearl HPS block 1 2 3 red dye % wt. 12.5 12.5 12.5 polyethylene % wt. -. -. . polynol A % wt. - - - dodecylbenzene sodium sulfonate % wt. - - - polystyrene 87.5 87.5 87.5 Total 100.00 100.00 100.00 PS stand. % wt. - -. ’- HPS beads % wt. - - HPS block % wt. - - -

Table 1 - continued

N 0)

MJ β> 1>

Φ u o Ch

Ch

-μ tn o cu

inm m O • τ ’in O O’T * * * - I * I I

N H O OIO> —lCO

O O o o <- <

Table

O O O LD - 1 ort> φ su 1 2 3 4 5 6 7 8 9 10 11 12 '> <rt Μ ft m Μ m « < Q Q O Φ CO P Φ ftin CO rH • h co Ό O id id <o i — 1 kO CM id X rH ID Tf O O what what what what m 2 σ » X r-t φ kO > U oo rt O cn O * » O what O O ’1—1 O σ co LD WHAT O or CM m and rH O CM σ O O O TO Lf) 00 ro CM o id rH O o O LD σ tn About CM m CM Ln vo O ID O O About what O o D O * · O o o K CM 1 cm <U rH tí kO> O Φ > N rt kD 0 x3 z what O kO co D CO 00 O 00 oo O p O what what ID ID 00 O 00 00 ID CM 00 O kO co O About σ O co oo -P co 0 rt 0 H 93 cm 0 Ln O rt) rt P g Y <J N P O Φ P §0 rH &>> 1 rt 44 rt -P H Φ 43 > O CD 0 ft Φ ro ví rt> co XI C rt Φ co e λ • m 0 Φ rt Q Φ rt • ro Ό rt Ή X! > S-I rt E-i co Λ · 0 g O rt d Ώ VI> N> 1-1 rt +> O • X.C0 Q VI> N N rt Φ. g <N O • H Ll s rt> VI φ> 1-1 -ro -P rt · XI g rt> i rt OJ 43> O O 0 ftr _44 • Η Φ> N M ffl <D • H G CO 4-1 rt co vi Η 0 XQ 44 44 44 • rl> Φ Φ H> • ro φ > rt Φ 0 N J3 co M 0 -ro φ -Η ft-mxi) CO Φ P • H -ro φ Ό -P to rt> 4-) Φ > C • H dP r4 co ω YO XJ YO rt rt 44 g > N 44 > rt g 0 0 G Φ ms > «KO x CM > CM H kO 93 YtJ Φ Φ * ft Ό rt ft rt 44 0 -P g Φ 0 C ft> 0 43 0) Μ 3 Z > Z co O n ω \ ftZ 4J N rt Ή O Φ -p ω rt ω Φ ω VCJ 0 Μ) φ ω Φ O -P> P Φ > ϋ what ft cnxj + »> O Η H P -P 44 -PXJ with ft ω ft p

Claims (1)

PATENT CLAIMS Premix for dyeing polystyrene plastics with improved dispersibility, increased opacity to achieve a higher gloss, characterized in that it consists of 10 to 15 parts by weight of organic dye and / or inorganic pigment, on a polymeric carrier, of 0.5 to 8 parts by weight of polyethylene with a melt index of 10 to 25 g / 10 min, from 0.005 to 0.5 parts by weight of a mixture of mono-, di- and triglycerides of fatty acids, from 0.00005 to 0.005 parts by weight of an alkali salt, preferably sodium, of dodecylbenzenesulfonic acid, up to 100 parts by weight contains polystyrene polymer. End of document