DE102007057951A1 - Use of a composition obtained by reacting the cardanol containing cashew nut shell liquid raw material with an ammonia or amine containing a primary amino group and formaldehyde by Mannich reaction for coating a surface of solid substrate - Google Patents

Abstract

Use of a composition obtained by reacting the cardanol containing cashew nut shell liquid (CNSL) raw material with (a) ammonia or an amine comprising at least one primary amino group, and (b) formaldehyde with the help of Mannich reaction, for the coating of surface of solid substrate, is claimed. An independent claim is included for coating the surfaces of solid substrates comprising applying a layer of benzoxazine containing composition on a substrate and subsequently hardening the layer, where the benzoxazine containing composition is obtained by reacting cardanol containing CNSL raw material with (a) and (b) with the help of Mannich reaction.

Description

Field of the invention

The The invention relates to a process for coating the surfaces solid substrates.

State of the art

Phenolic chimneys are still a relatively new class of epoxy resin hardeners. These are reaction products (condensation products) of cardanol (I), which is chemically a C ₁₅ -alkylphenol and is a main constituent of the oil obtainable from cashew nut shells (the so-called cashew nut shell liquid), with aliphatic (primary or secondary) amines and formaldehyde.

It It should be emphasized that phenalkamines as such are not used for coating purposes, but only as Epoxy resin hardener.

E. Calo et al. describe in Green Chemistry, 2007, 9, pp. 754-759 a process in which they convert cardanol into a specific benzoxazine monomer. The synthesis of this particular benzoxazine (abbreviated to Bz in the article) is described on page 756, left column, second paragraph. With this compound Bz, various polymerization reactions are then investigated.

Description of the invention

The The object of the present invention was a new process to provide for the coating of surfaces of solid substrates. Another object was to provide new compositions, dedicated to the coating of surfaces solid substrates are suitable.

• • hervorragende Haftung auf Metalloberflächen
• • ausgeprägte Hydophobie (Wasser perlt auf der Oberfläche ab, ohne Spuren zu hinterlassen)
• • hohe Barrierewirkung gegen Chemikalien
• • hohe Flexibilität (Schlagtiefung > 40 möglich)
• • guter Korrosionsschutz
• • gute elektrische Isolierwirkung
• • hoher Glanzgrad

The coatings should be characterized by the following features:

• • excellent adhesion to metal surfaces
• • pronounced hydrophobicity (water rolls off the surface without leaving any traces)
• • high barrier to chemicals
• • high flexibility (throat depth> 40 possible)
• • good corrosion protection
• • good electrical insulation
• • high gloss level

The present invention is a process for coating surfaces of solid substrates, wherein a layer of benzoxazine-containing composition composition is applied to a substrate and the layer is then cured, characterized in that it is a composition in the benzoxazine-containing composition obtainable by dissolving the cardanol-containing raw material CNSL in the manner of a Mannich reaction with (a) ammonia or an amine containing at least one primary amino group (NH ₂ group) and (b) Converts formaldehyde.

Another object of the invention is the use of compositions obtainable by dissolving the cardanol-containing raw material CNSL in the manner of a Mannich reaction with (a) ammonia or an amine containing at least one primary amino group (NH ₂ Group) and (b) converts formaldehyde, for the coating of surfaces of solid substrates.

It should be noted that the use of the composition according to the invention for coating surfaces of solid substrates is not described in the article cited above E. Calo et al. is disclosed. The article describes polymerization reactions of a single monomer (Bz), while according to the present invention it is important to use a mixture (composition) containing different benzoxazines for a very specific purpose, namely the coating of surfaces of solid substrates.

To the CNSL

The CNSL used in the course of the present invention is natural Origin - it gets out of the outer shells of cashew nuts (nuts of the tree Anacardium Occidentale) obtained by extraction and may be in terms of its Composition vary. Typically, it contains 60-65% Cardanol, 2-10% Cardol, 10-15% oligomers / polymers and 0-2% 2-methylcardanol and anacardic acid.

In In one embodiment, crude CNSL is used. this has the advantage of a substantial simplification of the coating process and also has economic benefits.

In In one embodiment, purified CNSL is used, wherein the purification by pretreatment and / or distillation can be done.

It may also be desired to subject CNSL to pretreatment to remove contaminants. Pre-treatment and distillation of CNSL can also be combined, especially if it is desired to use a color-stable CNLS with a particularly high content of cardanol. Particularly preferred pretreatment are chemical pretreatments, in which case the pretreatments with boric acid and with acetic anhydride, as described in US Pat WO 2006/108545 A1 and in WO 2006/108545 A1 are particularly preferred. In one embodiment, CNSL is used in the context of the present invention in a quality, as in one of the methods according to WO 2006/108545 A1 and in WO 2006/108545 A1 is obtained.

To the amines (a)

In In one embodiment, the component (a) used is ammonia one.

In a further embodiment, the component (a) used is an amine which contains at least one primary amino group (NH ₂ group).

In a further embodiment is set as a component (a) an amine selected from the group of Polyamines, with the following provisos for these polyamines Apply: (1) You must have at least one primary Contain amino group; (2) they must total at least contain two nitrogen atoms, one of which - as by Assignment (1) given - in the form of a primary Amino group must be present and the rest - independently from each other - in the form of primary or secondary or tertiary amino groups must be present. It may be aliphatic, aromatic, aliphatic-aromatic, cycloaliphatic and heterocyclic polyamines are used.

Examples suitable amines are:

alkylamines with linear or branched alkyl chains such as n-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, 2-ethylhexylamine, n-octylamine; aromatic Amines such as aniline, toluidine; alkylaromatic amines such as benzylamine; Polyethylene amines (ethylenediamine, diethylenetriamine, triethylenetetramine, Tetraethylenepentamine, etc.), 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,3-pentanediamine, 1,6-hexanediamine, 3,3,5-trimethyl-1,6-hexanediamine, 3,5,5-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, bis (3-aminopropyl) amine, N, N'-bis (3-aminopropyl) -1,2-ethanediamine, N- (3-aminopropyl) -1,2-ethanediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, aminoethylpiperazines, poly (alkylene oxide) diamines and triamines (such as Jeffamine D-230, Jeffamine D-400, Jeffamine D-2000, Jeffamine D-4000, Jeffamine T-403, Jeffamine EDR-148, Jeffamine EDR-192, Jeffamine C-346, Jeffamine ED-600, Jeffamine ED-900, Jeffamine ED-2001), meta-xylylenediamine, phenylenediamine, 4,4'-diaminodiphenylmethane, Toluenediamine, isophoronediamine, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, 2,4'-diaminodicyclohexylmethane, 1,3-bis (aminomethyl) cyclohexane, the mixture of one Methylene bridge linked poly (cyclohexyl-aromatic) amine (also known as MBPCAA) and polyaminoamides.

In a preferred embodiment, a monofunctional primary amine of the formula R-NH ₂ (I) is used as component (a), where the radical R is an alkyl group having a total of 1 to 30 C atoms or a Aryl group or substituted with one or more alkyl radicals aryl group having a total of up to 30 carbon atoms. When using the compositions according to the invention, in the preparation of which as component (a) the abovementioned monofunctional amines (I) are used, for coating purposes it has been found that these coatings were distinguished in particular by very excellent values in terms of flexibility, and furthermore by good acid resistance.

For the preparation of the compositions

at the Mannich reaction of cardanol with formaldehyde and amines Mixtures of benzoxazines and higher molecular weight products and unreacted cardanol. These mixtures are suitable without further Purification as thermosetting coating compositions. The coatings available therefrom have the in Task listed benefits.

For coating the surfaces solid substrates

The Compositions according to the invention are disclosed applied the surfaces of solid substrates. The kind and Way of applying is not critical in itself. Examples suitable methods of application include: doctoring, Painting, rolling, pulling (spatula), wiping, pouring, Rolling, Dipping, Drumming, Centrifuging, Flooding, Flow Coating, Vacuum painting, spraying (high pressure, low pressure, airless, airmix, Hot spraying process, Unicarb process, electrostatic Atomization).

The Curing of the compositions of the invention takes place after application to the surface of a solid Substrates and is usually at temperatures between 50 ° C and 300 ° C performed. Depending on the layer thickness and Curing temperature are the curing times in the range of a few seconds to several hours.

To the substrate

In In one embodiment, the substrate to be coated becomes selected from the group of metals, mineral materials (like stone, concrete, ceramics), plastics, glass, fibers. There are Metals, in particular iron, steel, copper, aluminum, tinplate, Nickel and gold as substrates to be coated are particularly preferred.

Examples

Example 1: Preparation of the composition

272.9 g cardanol were mixed with 30.7 grams of ammonia solution, 25% and 116.2 g formaldehyde solution (35% in water) in a 1 liter three-necked flask equipped with stirrer, Thermometer and reflux condenser under nitrogen purge Heated to 75-80 ° C for 3 hours. The still warm Reaction mixture was transferred to a separatory funnel. The aqueous phase rapidly settled and was released. The oil phase was washed with 100 ml of deionized water. The process was repeated until the washing water was neutral. The oil phase was then in vacuo at a maximum of 70 ° C. dried.

272.6 g of a clear, red-brown, oily liquid with an amine value of 57.2 mg KOH / g were obtained.

Examples 2-4: Coatings

(B2 to B4)

• • Pendelhärte nach König gemäß DIN EN ISO 1522
• • Haftung nach DIN EN ISO 2409
• • Schlagtiefung nach ASTM D6905

The liquid composition prepared according to Example 1 was applied by means of a doctor blade with 100 μm layer thickness to acetone-cleaned metal plates (steel test plates, material No. ST 1405) of size 150 × 70 × 1 mm and cured in a preheated oven at 220 ° C. with different times , After cooling the plates a uniform, very good, transparent and tack-free coating was obtained, which had different properties depending on the curing time. The experimental data are shown in Table 1:
The parameters mentioned in the last three columns of Table 1 were determined according to standard methods known to those skilled in the art, namely:

• • Pendulum hardness according to King DIN EN ISO 1522
• • Liability after DIN EN ISO 2409
• • knock down ASTM D6905

Table 1 example Curing time (min) Curing temperature (° C) Pendulum hardness (s) liability impact indentation B2 20 220 40 GT 0 > 40 B3 30 220 53 GT 0 <20 B4 60 220 140 GT 2 <10

all obtained coatings according to the examples B2 to B4 common was the pronounced hydrophobicity of Surface (water beaded off and left too after prolonged exposure no traces) and the associated high barrier effect.

Comparative Example 1

40 g of the material obtained in Example 1 were transferred to a chromatography column (filled with 300 g of silica gel 60, particle size 0.063-0.2 mm as a stationary phase, slurried with dichloromethane as mobile phase), with a little dichloromethane as solvent. The eluate was separated into 12 fractions and analyzed by thin-layer chromatography (TLC plates Kieselgel 60, Merck, with dichloromethane as the mobile phase). It was a phase with a substance with RF 0.95 identified as the main component and the corresponding fractions combined and concentrated on a Rotavapor at 60 ° C bath temperature. At the end, the residual dichloromethane was removed in vacuo. This gave 9.1 g of a pale yellow, low-viscosity liquid having an amine value of 81.6 mg KOH / g. According to investigations by the applicant, the obtained compound is that disclosed in the above-mentioned publication of E. Calo et al. described specific benzoxazine monomer Bz.

Comparative Examples 2-4: Coatings

(V2 to V4)

According to Examples 2-4, coatings were prepared with the substance prepared according to Comparative Example 1 and investigated. The results are shown in Table 2. Table 2 Comparative Example Curing time (min) Curing temperature (° C) Pendulum hardness (s) liability impact indentation V2 20 220 not measurable Coating not crosslinked Coating not crosslinked V3 30 220 not measurable Coating not crosslinked Coating not crosslinked V4 60 220 not measurable Coating sticky Coating sticky

It it turned out that in none of the comparative experiments V2-V4 a tack-free coating was obtained so that no Collect data regarding pendulum hardness, adhesion and depression left. The according to the comparative example 1 prepared substance apparently requires significantly higher Curing temperatures than those according to example 1 prepared substance. The experiments V2 and V3 led to a viscous, still liquid coating, in experiment V4 a sticky coating was obtained.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - WO 2006/108545 A1 [0013, 0013, 0013, 0013]

Cited non-patent literature

• E. Calo et al. describe in Green Chemistry, 2007, 9, pp. 754-759 [0004]
• E. Calo et al. [0009]
• - DIN EN ISO 1522 [0026]
• - DIN EN ISO 2409 [0026]
• ASTM D6905 [0026]
• E. Calo et al. [0029]

Claims (8)

Use of compositions obtainable by dissolving the cardanol-containing raw material CNSL in a Mannich reaction with (a) ammonia or an amine containing at least one primary amino group (NH ₂ group) and (b) reacting formaldehyde, for the coating of surfaces of solid substrates. Use according to claim 1, wherein crude CNSL starts. Use according to claim 1, wherein purified CNSL, wherein the purification by pretreatment and / or Distillation can take place. Use according to one of claims 1 to 3, wherein as component (a) an amine is used which contains at least one primary amino group (NH ₂ group). Use according to claim 4, wherein as component (a) employing an amine selected from the group the polyamines, wherein the following provisos for these polyamines Apply: (1) You must have at least one primary Contain amino group; (2) they must total at least contain two nitrogen atoms, one of which - as by Assignment (1) given - in the form of a primary Amino group must be present and the rest - independently from each other - in the form of primary or secondary or tertiary amino groups must be present. Use according to one of claims 1 to 5, wherein the substrate to be coated is selected from the group of metals. Process for coating surfaces of solid substrates, wherein a layer of a benzoxazine-containing composition is applied to a substrate and then the layer is cured, characterized in that the benzoxazine-containing composition is a composition which can be obtained by the cardanol-containing raw material CNSL (cashew nut shell liquid) in the sense of a Mannich reaction with (a) ammonia or an amine containing at least one primary amino group (NH ₂ group) and (b) reacting formaldehyde. The method of claim 7, wherein the curing thermally.