DE10229255A1 - Formulation, used e.g. as lacquer or printing ink, contains pale or transparent semiconductor as particles or coating on substrate particles as hardening and drying additive and to increase thermal conductivity - Google Patents

Abstract

Formulations contain pale or transparent semiconductor materials (I) in particulate form or (I)-coated particulate substrates (II) as hardening and/or drying additive. An independent claim is also included for use of particulate (I) or (II) for hardening, drying and/or increasing the thermal conductivity of lacquer coatings and printing inks.

Description

The present invention relates to the use of light or transparent semiconductor materials as Drying or hardening additive of paints and printing inks.

Many materials are used nowadays lacquered or printed. This makes properties like that possible Color and also durability of materials to improve. The sometimes long drying times are disadvantageous or the high temperature during drying. For automotive painting relatively high long drying lines are needed to dry the Paint before application of the next Ensure paint layer. could the drying time is reduced, so could the energy requirement and the length of these drying lines be reduced, resulting in significantly lower production costs would be connected.

Object of the present invention it is therefore a method for accelerating hardening of paints and inks to find that at the same time on simple Way performed can be. The hardening accelerators should be easy in the paint system or in the printing ink Have it incorporated, have a high level of transparency and only a low level Concentrations are used.

Surprisingly it has now been found that the curing and / or drying of Lacquer layers and printing inks can thereby accelerate by one finely divided the varnish or the printing ink in small quantities adds bright or transparent semiconductor materials. Through the Addition of this hardening accelerator the properties of the varnish and the printing ink are not at all or only marginally influenced.

The invention relates to Use of platelet or spherical bright or transparent semiconductor materials or with bright or transparent semiconductor materials coated spherical, platelet or needle-shaped Hardening substrates and / or drying of lacquers and printing inks. Preferably absorb the bright or transparent semiconductor materials in the IR range.

The invention further relates to Varnishes and printing inks containing the oxide semiconductor materials as a hardening accelerator or drying accelerator included.

Suitable light or transparent Semiconductor materials are, in particular, platelet-shaped or spherical indium oxide, Tin, tin oxide, antimony and their mixtures.

Have suitable semiconductor materials usually particle sizes of 0.01 to 2000 μm, preferably from 0.5 to 100 μm, in particular from 1 to 30 μm.

The semiconductor materials exist either homogeneous from the semiconductors mentioned or it is around spherical, needle-shaped or platelet-shaped substrates, which are coated one or more times with the semiconductor materials mentioned are. The substrates are preferably covered with only one layer.

The substrates can be spherical (spherical), platelet-shaped or needle-shaped. The size of the particles is not critical in itself. Usually have the spherical Particles with a diameter of 0.2-2000 μm, especially 5-300 μm and in particular from 5-60 μm. Both particularly preferred substrates are spherical substrates. Suitable platelet-shaped substrates have a thickness between 0.02 and 5 μm, in particular between 0.1 and 4.5 μm. The expansion in the other two areas is usually between 0.1 and 1000 μm, preferably between 1 and 500 μm, and in particular between 1 and 60 μm.

The substrates are preferably natural or synthetic mica platelets, graphite platelets, SiO ₂ platelets, Al ₂ O ₃ platelets, glass platelets, Fe ₂ O ₃ platelets, aluminum platelets, BiOCl platelets, SiO ₂ spheres, glass spheres, hollow glass spheres , TiO ₂ balls, polymer balls, for example made of polystyrene or polyamide, Fe ₂ O ₃ needles or TiO ₂ needles or mixtures thereof.

The coating of the platelet-shaped or spherical Substrates with the semiconductor materials are either known or can be carried out by methods known to the person skilled in the art. Preferably the substrates are hydrolyzed by the corresponding metal salts, such as. Metal chlorides or metal sulfates, metal alcoholates or Carboxylic acid salts in watery or conventional solvent solution coated.

For the homogeneously structured semiconductors as well as those coated with one or more semiconductor materials The semiconductor material is preferably microcrystalline to substrates built up.

Particularly preferred hardening accelerators are spherical Tin (IV) oxide, antimony (III) oxide, indium tin oxide (ITO) and mica flakes coated with ITO, tin (IV) oxide or antimony (III) oxide and mixtures thereof.

Particularly preferred drying and / or curing accelerators are transparent or light-colored semiconductor materials with a powder resistance of <20 Ω⋅m, preferably of <5 Ω⋅m.

A particularly preferred hardening accelerator is a tin (IV) oxide doped with antimony (III) oxide or a substrate coated with it, such as a mica plate. Also preferred are spherical SiO ₂ particles coated with tin (IV) oxide doped with antimony (III) oxide.

In addition to antimony (III), preferably Antimony (III) oxide, are halides, preferably chlorides and fluorides, still suitable as a dopant.

The doping depends on the semiconductor material used and is usually 1–30% by weight. , preferably 2-25% by weight, in particular 5-16% by weight, based on the semiconductor material.

Mixtures of curing accelerators can also be used be used, with no limits to the mixing ratio are.

Preferred mixtures are indium tin oxides with doped tin (IV) oxides and indium tin oxide with doped Zinc oxides.

The paint system or the printing ink can mixtures of two, three or more semiconductor materials are also added become. The total concentration depends on the paint or ink composition, but should not be more than 35% by weight in the application system.

The accelerator and / or drying accelerator the varnish system or the printing ink are preferably in quantities from 0.01-30 % By weight, in particular from 0.1-5 % By weight, particularly preferably in amounts of 0.5-4% by weight.

The hardening accelerator is before the application to an object in the varnish or the printing ink stirred. This is preferably done using a high speed stirrer or in the case of difficult to disperse, mechanically insensitive hardening accelerators by using a pearl mill or a shaker. Other dispersing units known to the person skilled in the art are also possible. Last the paint or printing ink is physically dried in the air or by oxidation, condensation, thermally, preferably using by IR radiation, cured.

Through the hardening and / or drying accelerator will the hardening and / or drying times of the lacquer layer or the printing ink in usually about 1/3 of the original Drying time reduced.

Especially with printing inks and Paint systems that harden or dry using IR radiation significantly shortened Drying times observed.

Surprisingly it was also found that the acceleration of the curing also increased overlying Paint layers have a very positive effect.

The invention further relates to Printing inks and varnish layers, which the semiconductor materials as Drying and / or curing accelerators contain. Suitable coating systems include, in particular, thermal curing Paints on solvent or water-based, IR lacquers, powder lacquers, enamel lacquers, but also Weld foil application and plastic, as well as solvent-based ones or watery Printing inks for everyone common Print types, e.g. gravure printing, flexographic printing, letterpress printing, textile printing, Offset printing, screen printing, security printing,

The following examples are intended to Invention closer explain, but without limiting it.

Examples

Example 1a (comparison)

In a physically drying commercially available polyester / acrylate clear lacquer, 10% by weight of TiO ₂ Kronos 2310 (TiO ₂ pigment with a particle size of approx. 300 nm) calculated on the lacquer formulation are incorporated by dispersing with zirconium dioxide balls (diameter 3 mm) , Dispersion takes place in a Dispermat at a peripheral speed of 12.6 m / s, 1 hour at 20 ° C.

Example 1b

Analogously to Example 1a, 8% by weight of TiO ₂ Kronos 2310 and 2% by weight of drying additive (a tin dioxide doped with antimony (III) oxide with a particle size of approx. 1 μm) are calculated in a physically drying polyester / acrylate paint onto the paint formulation Disperse incorporated with zirconium dioxide balls.

Example 1c: measurement results

Paint samples from Examples 1a and 1b are wet-coated on Q panels with a layer thickness of 200 μm. The dry layer thickness is 25 ± 2 μm.

The painted samples from example 1a and Example 1b are evaporated off for 5 minutes and irradiated with IR radiators with a total output of 3 kW from a distance Exposed 50 cm. The radiation duration is between 5 and 10 and varied for 15 min. The drying / curing is checked using a micro hardener Fischerscope at room temperature immediately after IR exposure using a diamond indentor and a final load of 3 mN. Every measurement is carried out three times and the average of the individual measurement results.

Aus den Mikrohärtemessungen ist eindeutlich ersichtlich, dass die Zugabe des Trocknungsadditivs die Trocknung/Aushärtung des physikalisch trocknenden Lackes beschleunigt. Bereits nach 5 Minuten IR-Bestrahlung der Lackprobe mit dem Trocknungsadditiv ist der Härtewert größer als der für die Lackprobe ohne Additiv nach 15 Minuten IR-Bestrahlung. Durch die Zugabe des Trocknungsadditivs wird sowohl die Zeitdauer zum staubtrockenen Zustand als auch die vollständige Aushärtung des physikalisch trocknenden Lacks deutlich verkürzt.The measurement results of the micro-hardening after different duration of the IR irradiation of the paint samples are given numerically in Table 1. Table 1:

The microhardness measurements clearly show that the addition of the drying additive accelerates the drying / curing of the physically drying lacquer. Even after 5 minutes of IR exposure of the paint sample with the drying additive, the hardness value is greater than that for the paint sample without additive after 15 minutes of IR exposure. By adding the drying additive, both the time required for the dust-dry state and the complete curing of the physically drying lacquer are significantly reduced.

Claims (11)

Use of light or transparent platelets or spherical Semiconductor materials or with light or transparent semiconductor materials coated spherical, needle-shaped or platelet-like substrates for curing and / or drying lacquer layers and printing inks. Use of semiconductor materials according to claim 1, characterized characterized that the semiconductor materials are homogeneous from bright or transparent semiconductor materials or sulfides are or as a coating on a platelet-shaped spherical, or acicular Substrate are applied. Use of semiconductor materials according to claim 1 or 2, characterized in that the semiconductor material indium (III) oxide, Indium tin oxide (ITO), antimony (III) oxide, tin (IV) oxide, zinc oxide or contains a mixture of said semiconductor materials. Use of semiconductor materials according to one of claims 1 to 3, characterized in that the substrate is selected from the group of mica platelets, graphite platelets, SiO ₂ platelets, Al ₂ O ₃ platelets, glass platelets, Fe ₂ O ₃ platelets, aluminum platelets, BiOCl platelets, SiO ₂ spheres, glass spheres, hollow glass spheres, TiO ₂ spheres, polymer spheres, Fe ₂ O ₃ needles, TiO ₂ needles or mixtures thereof. Use of semiconductor materials according to one of claims 1 to 4, characterized in that the semiconductor materials with antimony (III) or halides are doped. Use of doped semiconductor materials according to claim 5, characterized in that the semiconductor material with an antimony (III) oxide is doped tin (IV) oxide. Use of semiconductor materials according to claim 5 or 6, characterized in that the doping 1-30% by weight based on the semiconductor material is. Use of semiconductor materials according to one of claims 1 to 7, characterized in that the semiconductor material is microcrystalline is constructed. Use of semiconductor materials according to one of claims 1 to 9, characterized in that the oxidic semiconductor materials Particle sizes of 0.01 to 2000 μm exhibit. Lacquer layers and printing inks, characterized in that one or more bright or transparent platelet-shaped or spherical semiconductor materials or coated with bright or transparent semiconductor materials spherical, platelet-shaped or needle-shaped Substrates as curing and / or Drying additive included. Lacquer layers and printing inks according to claim 10, characterized in that they contain 0.01-30% by weight of semiconductor materials, based on the lacquer or printing ink, as a curing and / or drying additive hold.