CS241584B1 - Pigmented and filled low density polyethylene - Google Patents

Abstract

The invention provides a coating composition for extrusion coating on paper, cardboard, aluminum foil and plastic foil. Its essence lies in the fact that the coating composition contains heat-treated inorganic pigments, organic pigments with high heat resistance, mixtures of synergistically acting heat stabilizers of the polyphenolic and phosphite type, light stabilizers based on sterically hindered amines, light stabilizers of the hydroxybenzophenol or hydroxyphenylbenzotriazole type, low-density polyethylene. The pigmented and filled low-density polyethylene can be used: on various substrates, such as paper, cardboard, Al foil.

Description

241584

BACKGROUND OF THE INVENTION The present invention relates to pigmented and filled low density polyethylene for use in extrusion coating on paper, icartone, aluminum foil and plastic films.

Extrusion application of melts to strip substrates as; is paper, carton and grill foil, is a commonly known technology in which the polymer or polymer blend is extruded to the treated material, moving at a suitable rate. This technology is described in the textbooks and in the patent literature, such as in British Patent Nos. 688,637 or 992,388.

The best recast technology is the extrusion of low-density polyethylene, high process speeds have been achieved, with very good film-thickness uniformity in the transverse and transverse directions, good adhesion not only to porous substrates such as paper and cardboard, but also to aluminum foil.

Particularly suitable low-density polyethylene has a specific weight of about 9-13 µg / m 3, with a wide molecular weight distribution and an ITT of about 7 g / 10 min. Nowadays, other polymers such as polypropylene, polyethylene terephthalate and polyamide with the aim of achieving better barrier and surface properties of the polymer layer are being used as extrusion coating. These polymeric materials are relatively more expensive than polyethylene for extrusion coating, their preparation, as well as extrusion coating technology are quite demanding technological operations.

In a suitable manner, the barrier and surface properties of the extruded film-polyethylene can be changed with a suitable pigment or filler. The technological process of extrusion coating of pigmented and filled polyethylenes is associated with the difficulty of the degradation of the polyethylene due to the high processing temperatures of the addition of the extruder screw granulate. the formation of gaseous products which cause tearing of the diaphragm and the formation of inhomogeneities in the extruded film.

Reducing the extrusion temperature, respectively. by increasing the thermal stabilizer content in the polyethylene, the oxidation of the melt surface is greatly reduced, resulting in reduced adhesion of the extruded film to the backing as well as a lower surface tension of the filled film and a reduction in the corona discharge surface finish , by flame or by oxidative impregnation.

The aforementioned drawbacks are eliminated by the present invention, which comprises 3 to 75 wt. thermally treated inorganic pigments and fillers, such as titanium dioxide, zinc oxide, calcium carbonate, kaolin, talc and mixtures thereof, 0.5 to 10% of high-temperature organic pigments, 25 to 97% of low density polyethylene with melt flow index, 3 up to 70 g / 10 min, 0.1 to 3% of heat stabilizers and polyphenolic and phosphite type and mixtures thereof, 0.1 to 2.0% light stabilizer for spherically shielded amine and 0.1 to 1% Light stabilizers of hydroxybenzophenol or hydroxyphenylbenztriazole type and processing aids.

Pigmented and filled low density polyethylene produced according to the invention can be used directly or in a mixture of pigmented and filled concentrates with clarified non-filled polyethylene suitable for extrusion coating.

By using filled and pigmented polyethylene for extrusion coating, the appearance of the chewing-wanted material is improved, the surface has a higher opacity, is duller, and has a more natural feel. A good aesthetic effect can be achieved by the use of low-quality pads (unpainted paper and cardboard). Increasing the polarity of the surface due to the presence of inorganic fillers improves the suppressability, the surface has a better color acceptance, the color adhesion to the polyolefinic surface improves, the more absorbent the color. The presence of inorganic fillers and a light stabilizer based on spherically shaded amines increases the efficiency of the corona surface treatment, thereby reducing the intensity of the root discharge, respectively. higher adhesion values are achieved for suppression of sticking. The material can be welded without changing, while welding to other kinds of materials, such as aluminum foil. the strength of the weld increases as well as the welding temperature. > ΐ

Depending on the type of filler used and the pigment, the barrier properties of the laminated materials, such as the vapor permeability and the vapor permeability, can be varied, and the values can be increased or decreased. It is also desirable to provide a surface friction coefficient for the pigmented and filled polyolefins.

With the use of organic pigments resistant to high extrusion temperatures, any color shade of extruded films can be achieved, the intensity of the color of the color being altered by the content of inorganic pigments and fillers present in the polyethylene.

The main problem in the extrusion coating of pigmented and filled polyethylene is the lower thermal stability of the melt, the strength exhibiting a strong thermal degradation of poly (ethylene), which produces gaseous low molecular weight products.

As the extrusion coating process is carried out with relatively high extraction rates of 211584 moles of melt from 60-400 m / min, with very small film thicknesses of 20-40 µm, the gas bubbles in the melt cause tearing of the melt curtain, while there are unevennesses on the surface of the extruded film until the non-covered rests on the substrate are formed.

In order to obtain sufficient thermal stability of the extruded pigment and filled polyethylene, it is necessary to use a stabilizing system which allows to operate at high extrusion temperatures of 290 to 320 ° C without degradation of polyethylene.

Polyethylene for extrusion deposition in the presence of inorganic pigments and fillers need to be stabilized by a synergistic mixture of desolidol and phosphite stabilizers in a quantity that depends on the amount and type of pigments and pigments. If high surface tension of extruded film-filled polyethylenes is required, it is necessary to use some of the types of light-stabilized amine-type light stabilizers that increase the resistance to sunlight and radiation. Better lightfastness can be achieved by adding light stabilizers of the hydroxybenzophenol or hydroxyphenyl-benzatriazole type. EXAMPLE 1 (Pigmented and filled low density polyethylene was prepared on a mixing agglomeration extruder by mixing 20% by weight of micronized calcium carbonate, 3% by weight of titanium dioxide, 0.3% by weight of tris (phenylethyl) phosphite, O 3% by weight of pentaerythrityll-tetrakis 3, (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 0.4% by weight of a spherically shielded piperidine-type amine with 76% by weight of low density polyethylene having a specific gravity of 913 kG / m 3 and a melt index of 7 g / 10 min. The talkto prepared pigmented and filled polyethylene was directly processed on a loading extruder at an extraction rate of 180 m / min on unbleached kraft paper weighing 80 g / m 2, the deposit of pigmented applied film was 35 g / m 2, with a uniform coating with good covering capability at extrusion temperature of 30 ° C, 5 ° C and 8 mN / m of high-grade and polyethylene-treated one-layer treatment. Example 2

Pigmented and filled polyethylene was prepared on a mixing and granulating extruder by mixing 43 wt. % micronised calcium carbonate, 7 wt. % of titanium dioxide, 0.5% by weight of tris- (phenylethyl-i-phosphite, 0.6% by weight of pentaerylcrityltetrakis 3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 0.8% by weight of spherically shielded amine piperidine type with 48% low density polyethylene having a specific gravity of 913 kg / m 3 and a melt index of 7 g / 10 min.

The pigmented and filled concentrate thus prepared had to be mixed 1: 1 with polyethylene suitable for extrusion coating, preferably polyethylene with a melting index of 7 g / 10 min prior to extrusion coating. The extrusion coating technology was as in Example 1. Example 3

Pigmented and filled low density polyethylene was prepared on a mixing agglomeration extruder by mixing 22 wt. % talc, 5 wt. % zinc oxide, 0.25 wt. % of tris-nylon phosphite, 0.35 wt. % octadyl-3- (3,5-dl-tert-butyl-4-hydroxyphenyl) propionate, 0.4 wt.% of spherically shielded piperazine-type amine and 72 wt .-% low density polyethylene with specific gravity 912 m / m, melt index 20 g / 10 min This prepared pigmented and filled polyethylene was processed on an extruder coating apparatus as in Example 1. Example 4

The low density polyethylene filled concentrate was prepared on a blending agglomeration extrusion apparatus by mixing 60 wt. % of micronised calcium carbonate, 0.8 wt. % tris- (phenylethyl) phosphite, 0.8 wt. % panta-ethyl-tetracls-3- (3,5-di-tert-butyl-4-hydroxyphenyl-propionate, 0.7% by weight of 2-hydroxybenzophenone, 0.7% by spherical thiene) of a piperidine-type amine with 38 percent by weight of low density polyethylene and a melt flow index of 20 g / 10 min.

The pigmented low density polyethylene concentrate was prepared on a tomist blender by mixing 50 wt. % of titanium dioxide with 35 wt% of low density polyethylene melt index 20 g / 10 min and 15 wt% of low density polyethylene with melt flow rate of 70 g / 10 min.

The mixture of granules for extrusion coating was prepared by mixing 30wt. % of the filler (concentrate, 8 wt.% pigment concentrate and 52 wt.% low density polyethylene with a tartrate index of 7 g / 10 min.

The extrusion coating technology was selected as in Example 1. Example 5

Pigmented and filled low density polyethylene was prepared according to point 1. 5% by weight was added to the granulate. parts of a red organic pigment pigment concentrate in polyethylene. Ex-

Claims (1)

241584 of the trusion coating was the same as in Example 1. By suitable composition of the stabilizing system, heat treatment of the fillers and pigment, it is possible to prepare materials which can be extruded on the spit pads, such as paper, cardboard, aluminum foil at high, pull-out speeds up to 350 m / min and 20 g / m 2, where the coating has good adhesion to the substrate, is free of cracks and surface defects, is evenly distributed in the transverse and longitudinal faces, with uniform pigment degradation and polyethylene fillers. PR E D M e τ Pigmented and Filled Low Density Polyethylene for Extrusion Manipulation on Paper, Cardboard, Aluminum Foil and Plastic Films characterized in that the coating composition contains 3 to 75 wt. % of heat treated inorganic pigments and fillers, 0.5 to 10 wt. % of organic pigments having a high heat resistance, 0.1 to 3 wt.% of the synergistically disposed polyphenolic and phosphite type stabilizers, 0.1 to 2.0 wt. % of light stabilizers based on sterically shaded amines, 0.1 to 1.0 wt. % of the light stabilizers of hydroxybenzophenol but hydroxyphenylbistriazole type, 25 to 97 wt. % of low density polyethylene with a melt flow index of 3 to 70 g / 10 minutes. Severograíia, n. P., Plant 7, Most Price 2,40 CZKs OP R A V A to PVAO No. 241584 (51) Int. Cl.4 C 08 L 23/06 The correct name of the third author is: PETROJ JAROSLAV RNDR. CSc., BRNO, OFFICIALS AND DISCOVERIES