CS259462B1 - Air-drying paint - Google Patents

Abstract

The solution concerns the field of coatings and solves the technical problem of coatings with a reduced content of siccative components. The essence of the solution is siccative with a rhodanocobalt complex, which is more effective than known types of cobalt siccatives. The solution can be used in the production and use of coatings and printing inks.

Description

The invention relates to an air-drying coating material containing siccative components.

Air-drying paints are still widely used in many industries and households, especially in protecting various materials from the corrosive effects of external atmospheric influences. The most commonly used paints are based on polymerized or isomerized drying oils, alkyd resins, epoxy ester resins, and the like.

The quality of the paint film is determined not only by the type and composition of the paint itself, but also by the speed and perfection of drying of the applied film, which to a decisive extent affects the amount and type of siccative agent. The most important component of siccative agents are salts of divalent cobalt, most often cobalt salts of organic acids (octoates, naphthenates, resinates, etc.). In recent years, the availability of cobalt on the world market has been increasingly poor and its prices have reached considerable heights.

Due to the continued depletion of cobalt ore deposits, no significant improvement can be expected in the future. For this reason, as well as due to the harmfulness to health and environmental protection aspects, a replacement for cobalt-based siccative agents is being intensively sought, but the results achieved so far are not very encouraging. No significant success has been achieved so far in attempts to solve siccative agents with a reduced cobalt content.

Based on extensive experimental work, we have now found air-drying coatings based on resin, oleoresin or oil polycondensates, optionally containing fillers, pigments, solvents and other substances, siccified with a rhodanocobalt complex or its solutions.

where:

Q/R ¹ COO/ ₂ CoSCN) m] nZ r! is an aliphatic or cycloaliphatic radical with a number of carbons in the molecule up to 35 r^ is an aliphatic radical with a number of carbons from 1 to 4

Z is R OC 1 2 CH 2 OH and/or butanol or isobutanol

M is Na, K or NH^ n - 2, in an amount corresponding to 0.001 to 0.1% of cobalt in the dry weight of the coating material or a mixture of this complex with Pb, Ca, Zn or Mn-octoates, naphthenates or resinates in an amount corresponding to 0.001 to 0.5% of the metal in the dry weight of the coating material.

Compared to the current state of the art, the coatings according to the invention can produce coating films of comparable quality, with comparable drying and film drying speeds, even with half the amount of cobalt in the dry matter of the coating. In some cases, very good coating film parameters were achieved even when using only a third of the usually used amount of cobalt siccatives. By reducing the cobalt content in the coating according to the invention, not only is a scarce raw material saved, but the aging of dried coating films is also improved.

The rhodanokobalt complex is used in the coatings according to the invention in the form of solutions in a mixture of aliphatic and aromatic or cyclanic solvents. (White spirit, aromatol, etc.) and butanol, isobutanol, diacetone alcohol, toluene, xylene, ketones, etc. The ratio of these components in the solution must be addressed to prevent premature precipitation of the coating binder with the siccative component of the rhodanokobalt complex, which must not separate from the drying material during the gradual evaporation of the individual solvent components.

Each coating composition according to the invention therefore has a different composition of solvents necessary to achieve optimal drying.

Paints are usually supplemented with substances that prevent or slow down the formation of scales (ketoximes), substances that improve the surface properties of the materials (silicone oils, fluorinated oils, etc.) and other properties, as well as fillers, pigments, etc. Some types of paint can also be used as transparent, especially when protecting the surface of wood.

Example 1

By mixing a 5% solution of cobalt octoate in white spirit, with a mixture of n-butanol and ethylene glycol monoethyl ether and potassium rhodanide in a molar ratio of Co-octoate:KSCN = = lsl, a solution of a siccative agent containing 1% cobalt in dry matter is prepared.

Alkyd resin PL 65 (60% solution in white spirit), prepared by polycondensation of linseed oil, phthalic anhydride and pentaerythritol, is mixed with 0.1% methyl ethyl ketoxime and 1% solution of lead octoate in white spirit and the prepared solution of rhodium cobalt complex, in an amount corresponding to the content of the respective metal in the dry matter according to the table.

Table

Drying time

Drying rate (pendulum, %)

25°C (days) 0.03% Co ^a 0.02% Co ³ 0.01% Co ^a 0.03% Co 0.3% Pb 0.3% Pb 0.2% Pb 0.1% Pb standard 1 7.9 5.9 4.9 5.6 3 9.5 8.5 6.3 7.9 10 24.4 13.4 10.8 13.6 3h/105°C 51.6 48.4 30.4 48.7

b a - rhodanocobalt complex, b - Co-octoate

The results show that siccation with a rhodanocobalt complex is significantly more effective than existing siccation at the same metal content in the dry matter, and good drying results can be achieved even with a reduced cobalt content in the form of a rhodanocobalt complex.

Example 2

By mixing a 5% solution of cobalt naphthenate in white spirit or BTA 50 aromatol, ethylene glycol monobutyl ether and sodium rhodanide in a molar ratio of Co-naphthenate:NaSCN = 1:1, a solution of a siccative agent containing 2% cobalt in dry matter is prepared.

Epoxy ester 1/16 RS 40-50X is prepared by esterification of Epoxy 1/16 with a mixture of soybean oil fatty acids and DEDICO acids. A 50% xylene solution of this epoxy ester is sicculated with varying amounts of rhodium cobalt complex and with cobalt naphthenate in a standard manner.

The coatings are applied to the glass with a 0.12 mm gap ruler and the drying speed is monitored according to ČSN 67 3053. The results are shown in the table.

Table

Drying speed (h) Pendulum film hardness (%)

Siccation A ^B 1 ^B5 1 day 10 days 3h,100°C standard desiccant naphthenate Co (0.028% Co) 1 5 25 8.9 22.8 48.9 siccative according to the invention (0.014% Co) 1 5 25 14.2 35.5 52.2 siccative according to the invention (0.007% Co) 1.5 5 30 7.9 24.7 50.6 The results show that in dry matter, reducing it by up to a third The amount of rhodanocobalt complex siccative can be reduced to the amount used so far (in the form of Co-naphthenate). cobalt

Example 3

The air-drying primer is prepared by mixing and homogenizing the following substances:

parts by weight of alkyd resin RS 55/S25 parts by weight of iron red parts by weight of barium sulfate

12.6 parts by mass of white spirit 0.6 parts by mass of siccative complex from example 1, containing 1% Co 1.2 parts by mass of lead octoate containing 10% Pb in dry matter 0.6 parts by mass of manganese octoate containing 2% Mn in dry matter

The paint dries to stage A in 2.5 hours, stage Β _χ is reached in 7 hours and stage Bg in 27 hours.

After 1 day, the film hardness (measured by pendulum, %) was 5.9, after 10 days it was 29.0, and after 3 hours at 105 °C the hardness was 54.1.

Claims (1)

OBJECT OF THE INVENTION Air-drying paint based on oily, oil-resins or resinous polycondensates or fillers, pigments and solvents, characterized by being dicatified by a rhodanocobalt complex Q / R ¹ COO / ₂ CoSCN) n Z wherein R ¹ is an aliphatic or cycloaliphatic radical having the number of carbons in the molecule 6-35, R ² is an aliphatic radical of carbon number 1 to 4, Z is R ² OCH ₂ CH ₂ OH and / or or butanol or isobutanol, M is Na, K or NH ₄ , n ^ 2, in an amount corresponding to 0.001 to 0.1% cobalt in the dry matter of the paint or mixtures of this complex with Pb, Ca, Zn or Mn octoates, naphthenates or resinates in an amount corresponding to 0.001 to 0.5% metal in the dry matter of the paint. Sevarography, n. P., MOST