DE2813319A1 - Alkali silicate soln. contg. polyimine or polyester - as binder for storage-stable paint, giving weatherproof elastic films - Google Patents

Abstract

A binder based on an alkali silicate soln. has is not >20 wt.% silicate solids, and contains a high-mol. polyimine and/or a polyester from phthalic acid and pentaerythritol in soln. It is used as a binder for paints. The paints have good flow and thixotropic properties, and are storage-stable. They give weatherproof, elastic, crack-free films on a variety of substrates. They can be applied by a roller without spattering. Pigments are easily dispersed.

Description

description

281331S

The invention relates to a binder based on alkali silicate solutions, in particular binders for paints which are improved over previously known similar agents Possess properties.

The use of alkali silicate solutions as binders for paints has been known for a long time. However, as alkali silicate solutions just the diverse requirements that are placed on binders for paints, such as adequate chain resistance and elasticity as well as the positive influencing of the paints in terms of flow, thixotropy and good Processability with long shelf life, not sufficient * meet, numerous publications have already appeared that deal with modifications of alkali silicate solutions for improvement their properties as binders for paints. It is known to use additives for elastification To use polyacrylates or phenolic and urea resins «2ur Improvement of the crack-free film formation and the waterproofing wedge: it is known to use triglycidyl isocyanurate with an epoxide content of over 14% and water-soluble amines in silicate solutions (DE-OS 1 669 181). In practice, however, it has been found that there is still no binder for paints, all of that has the properties mentioned above.

The invention has therefore set itself the task of a binder on the basis of alkali silicate solutions, especially for paints, to create ideally all properties combined, which are required of a binder for paints, and in particular the achievement of good flow

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as well as good thixotropic properties of the paint, good processability and long shelf life of the same as well as crack-free film formation on a wide variety of substrates and, moreover, good weather resistance and a pronounced elasticity.

According to the invention, this object is achieved by a binder the basis of an alkali silicate solution in that the alkali silicate solution has a silicate solids content of at most 20 wt .-% and also a high molecular weight polyimine and / or a polyester from phthalic acid and pentaerythritol in contains dissolved form.

The silicate solids content of the alkali silicate solution must not exceed 20% by weight, otherwise the desired combination of properties will not be achieved. The molar ratio of SiO ₂ : alkali oxide in the alkali silicate solutions _{can vary} within wide limits and depends on the particular purpose of the binder.

Sodium and potassium silicate solutions are particularly suitable as alkali silicate solutions or their mixtures.

The amount of polyimine is up to 6% by weight and varies in particular between 0.2 and 5.0% by weight. The amount of the ester preferably does not exceed 4% by weight and is in particular between 0.2 and 3.0% by weight.

Preferably, the polyimine used has a 50% strength aqueous solution has a viscosity, measured with a Brookfield viscometer (20 ⁰ C, 20 rpm) from 10,000 to 20,000 mPas.

The polyimine used is preferably cationic. For example one can use a product which is commercially available under the trademark Polymin from BASF.

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The ester used preferably has a KSN softening point of 90 to 105 ° and an acid number according to PIN 53402 from 190 to 205. A product that has been found to be particularly useful is called "Phthalopal ■ PP is in trade.

It is also useful to add a neutralized water-soluble acrylic resin in dissolved form to the binder according to the invention, this resin preferably having a current viscosity at 20 ^° C., measured with the Brookfield viscometer III / 6, of 3000 to 6000 mPas in 40% aqueous solution having. A material that is commercially available under the trademark Acrytex W 240 from Rohm GmbH has proven to be particularly suitable.

Paints are used using the binder according to the invention available, which have the following properties in particular: easier dispersibility of the pigments used, better flow, better workability (the paints are particularly suitable for rolling without spraying) and strong thixotropy.

The following examples illustrate the invention. example 1

70 parts by weight of potassium silicate having a weight ratio Me_0 siop of 1: 2.5 and a solids content of 27 _r 7Gew .-% are diluted with 27.5 parts by weight of water. 2.5 parts by weight of a high molecular weight polyimine (Polymin P, available from BASF) are dissolved in this dilute potassium silicate solution. Using this binder, it is possible to produce paints which are stable in storage and which run very well and are easy to process, have high elasticity, produce crack-free paints and, moreover, are weatherproof.

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Example 2 2Ü3319

From 13.4% by weight of a 50% sodium hydroxide solution, 66.6 % By weight of water and 20% by weight of a polyester made from phthalic acid and pentaerythritol (available under the trademark Phthalopal PP from BASF) a polyester solution is produced in such a way that first the sodium hydroxide solution is diluted with the water, whereupon the polyester is dissolved.

A potassium silicate solution with a weight ratio Me-O: SiO »of 1: 2.4 and with a solids content of 27.5% is placed in a vessel in an amount of 69.8% by weight, whereupon it is diluted with 26.2% by weight of water. Then in the solution obtained 2.5 wt .-% of a high molecular weight polyimine (available under the trademark Polymin P from BASF) and 1.5% by weight of the polyester solution obtained in the manner described above.

This gives a binder which, when added to paints, has particularly pronounced thixotropic properties confers.

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Claims (7)

MÜLLER-BORE · Σ> ΕΤ7ΐ?: »Ϊ5Ι. · SCHÖN · HERTEL PAIEHTAlfWALTE 2613319 DR. WOLFGANG MÜLLER-BORE (PATENT ADVOCATE FROM 1927 - 1975) DR. PAUL DEUFEL. DIPL.-CHEM. DR. ALFRED SCHÖN. DIPL.-CHEM. WERNER HERTEL. DIPL.-PHYS. S / W 28-15 company Woellner works 6700 Ludwigshafen / Rhine Binder based on alkali silicate solutions Claims Binder based on an alkali silicate solution, characterized in that the alkali silicate solution is a silicate solid content of a maximum of 20 wt .-% and a high molecular weight polyimine and / or a polyester from phthalic acid, and pentaerythritol in dissolved form. 2. Means according to claim 1, characterized in that the amount of polyimine up to 6 wt .-% and / or the amount of Esters is up to 4 wt .-%. 909841/0064 SIUJfCHEIT 86 · SIEBEHTSTH. 4 POST BOX 860720 KABSI .: MXTEBOPAT TEi. <089) 474003 TELEX 5-24285 ORIGINAL INSPECTED «■ - O mm 2913319 3. Agent according to claims 1 to 2, characterized in that the polyimine as a 50% aqueous solution has a viscosity, measured with a Brookfield viscometer (20 ⁰ C, 20 upm) ·
from 10,000 to 20,000 mPas. 4. Means according to claims 1 to 3, characterized in that that the polyimine is cationic. 5. Composition according to claims 1 to 4, characterized in that the ester is a condensation product of phthalic acid and
Is pentaerythritol and has a KSN softening point of 90 105 ⁰ C and an acid number according to DIN 53402 of 190-205. 6. Agent according to claims 1 to 5, characterized in that the alkali silicate solution is also a neutralized one
Contains acrylic resin in dissolved form. 7. Agent according to claims 1 to 6, characterized in that the acrylic resin in 40% aqueous solution has a current viscosity at 20 ⁰ C, measured with a Brookfield viscometer III / 6, of 3000-6000 mPas. 909841/0 064