DE2410955A1 - COATING MATERIAL THAT IS CONSTANT TO MOISTURE AND CHLORINATED SOLVENTS - Google Patents

Description

MÖHLSTRASSE 22, NUMBER 48 39 21/22

<983921/22>

THE DOW CHEMICAL COMPANY, Midland, Michigan / USA 2030 Abbott Road ;

Coating compound that is resistant to moisture and chlorinated solvents

The invention relates to a coating based on a volatile solvent, resistant to attack and the Formation of "pinholes", called "pinholes", is persistent during evaporation or the curing process.

It has now been found that coatings or paints applied from a film-forming resin formulation containing a volatile solvent as a carrier for the film-forming component can be made highly resistant to the passage of vapors (moisture, solvents and solvent decomposition products) by using the Formulation of 5 to 50 parts by weight / 100 parts of the total film-forming composition incorporates a finely divided, porous binder or a finely divided, porous cement and applies the resulting mixture, while the cement is essentially in a dispersed state in the formulation. The coating is then cured in the heat at a temperature of at least 21 ^° C. and preferably from 50 to 77 ^° C. for non-phenolic, film-forming resins and at about 250 to 350 ^° C. for phenolic resins, especially if harder coatings are desired . In one embodiment, an amine cured epoxy phenolic resin (such as that sold under the trademark "Piasite No.7111"

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is sold) with a cement, preferably a highly refractory one Cement, mixed, being 5 to 50 parts, preferably 7 1/2 to 12 parts, cement / 100 parts by weight of the total Wording used.

In another embodiment, a phenolic formulation is used (such as that commercially available under the trademark "Heresite") in a similar manner 'with a cement in an amount of 5 to 50 parts by weight per 100 parts by weight of the total formulation mixed. It is desirable to have from 7 »5 to 15 parts and preferably from 7 1/2 to 12 parts cement / 100 parts by weight Use overall formulation.

The cements found to be preferred for use in the present invention are high alumina cements (containing 36 to 42% AlpO, 36 to 42% CaO, 7 to 18% iron oxides, 5 to 10% SiO ₂ ) and portland cements (containing 28 to .53 wt.% C, S, 19 to 49 wt.% C ₂ S, 4 to 11 wt.% C ₃ A, 8 to 13 wt.% C ₄ AF, 2 , Contain 8 to 4.0% by weight CaSO ^ and 1.8 to 2.9% by weight MgO) (C ₂ S = dicalcium silicate; C ^ S = tricalcium silicate _{; C 3} A = tricalcium aluminate; CrAF = tetracalcium aluminum ferrite), when they are in the form of fine powders or dust. The density and / or particle size should be such that the cement is suspended in the formulation during use. The higher alumina cements are preferred because they have a lower density than the Portland cements and therefore remain more easily suspended during use.

The preferred resins useful as coatings in degreaser contain about 50 to 70 weight percent resin solids and have a high chemical resistance to attack by solvents such as chlorinated Solvents and moisture that usually go together

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occurs with chlorinated solvents when used in vapor degreasing processes. Other resins, which are useful are lower solids formulations. The type of resin used depends on the Purpose from. The addition of cement to any essentially film-forming formulation gives some Improvement in impenetrability or opacity.

Although initial tests indicated that a firmly adhering coating was obtained if the surface was the same as before described, permanent coating is coated or covered by a cured base coat on crosslinked Applying epoxyamine, which contains lead silicochromate, with or without iron oxide pigment, tests in the company or on a commercial scale, these results have not been confirmed, and although a basecoat has been found to work together with the top coat, which contains cement, does not become detrimental, there is no particular benefit in using the base coat used.

The following examples illustrate the invention without restricting it.
example 1

Thirteen plates, approximately 10 χ 25.4 cm (4 "XiO") were prepared, by cleaning the surface well and then degreasing the surface after cleaning. Different Compounds were applied to the panels, cured, and each examined by placing it in a for 24 hours Steam degreaser provided. The type of change, though present, when operating the degreasing system or the color of the liquid in the degreasing system as well as the effect, when boiling acidic water is introduced into the degreaser are given in the table below.

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Sample no.
D4044-25 1 Base coat Deck over 2 none 3 p + c ( ² ^ Il 4th
5 P + C + FG ^ Il 6th
7th P + FG
P. _TC (4) σ
co 8th P.
P. TC + C
TC + FG 00
co 9 P. TC + C + FG co 10 P + C TC O
to 11 P + C TC + FG 12th P + FG TC 13th P + FG TC + C P + FG + C TC

Results after 24 hours of exposure

Degreasing plant

boiling sour water

no change

Il Il

(D P

(2) C.

(3) PG (4) TC

Blisters, getting rusty

the coating falls off

the coating falls off

Liability of the coating lost

Blisters, getting rusty

no change

some bubbles, some rusting

no change

Liability is lost Liability is lost a little rusty Liability is lost the coating falls off

= Basecoat alone (a commercially available crosslinked amine-cured basecoat, which contains lead silica chromate, trademark Piasite 7103, owned by Wisconsin

Protective Coating Corporation being sold)
= Cement (with high aluminum content of the cement, which has the following approximate composition

has: 37.7% CaO, 38.5% Al ₉ CU, 12.7% Fe ₉ O ₃ , 3.9% FeO, 5.3% SiO ₉ , 0.1% MgO, 0.1% SO, ) = £ glass fiber. "

= Topcoat, (a commercially available epoxy-phenolic formulation marked with a ^

Amine is hardened and sold under the trademark Piasite No, 7111) ς ~>

It can be seen that when the base silver slide is used alone no effect on the material is observed within 24 hours when treated in a steam degreasing system However, if acid and water are added to the degreaser in the steam degreaser, conditions commonly present in most vapor degreasing processes, the base coat is not adequate protection and the blistering and rusting of the plate cannot be prevented. The addition of the refractory cement to the The base coat alone has no special effect in the vapor degreasing system. However, if you have boiling sour Adding water to the degreaser will cause the coating to fall off the metal plate.

The table shows as a whole that the base coat is insufficient to cover the refractory cement and / or the glass fibers with favorable results to keep. A base coat plus a top coat alone are without cement, as in the example 5 is no better than the primer alone. However, if you add cement to the top coat and If these are used as in Example 6, no noticeable changes occur in the appearance of the surface. The easy one Adding fiberglass to the top coat (no cement), the Applied over a base coat will result in some blistering and rusting if the panel exposed to boiling acidic water in a steam degreaser.

Example 2

A further example uses a 19 liter (5 gallon) degreaser, which contains four holes through its wall, mended or repaired. Three of the holes come with a usual Top coat (no cement), especially Piasite No.7111 » (registered trademark for an amine-cured epoxy-phenolic resin), patched over a glass fiber fabric and

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A corresponding coating agent from Piasite * ■ ' is brushed onto the fiberglass cloth in order to impregnate the fiberglass cloth and create a smooth surface. One of the holes is marked with Piasite No. 7111 and a high alumina cement, pouring the resin over the fiberglass patch and applying sufficient coating agent to create a relatively smooth surface. After hardening, the degreasing system is operated first with water and then with solvent and finally with solvent and water and then HCl is added to bring the degreasing system into a clean state. The three holes that were patched with the top coat and glass fibers show leaks after a few weeks in operation, whereas the glass fiber patch with a cement top coat showed no leaks.

After these observations, the system was drained and the three leaks were closed by simply apply a layer of Piasite No. 7111, which is refractory cement compositions contained, brushed. The degreasing system was again first with water, then with solvent and then started up with water solvent to which acid had been added. After several weeks in operation the degreaser worked normally and none occurred Breakthroughs or leaks in the patched areas.

Example 3

A cardboard box, about 0.6 m (2 ¹ sqare) was contained to that described in Example 2 composition, the refractory cement, coated, and a layer of wide-mesh glass fiber fabric was pressed onto this coating and then again to the ground, the refractory Contained cement coated. After hardening, the

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Cardboard used as a vapor degreaser by putting a Put a small amount of solvent in the soil and put a heater in place to cause the solvent boiled. After several weeks in operation, the degreasing system was still working normally and not leaking Spots appeared and there was no evidence that the coating was degrading.

Example 4

A coating composition was prepared in the same manner as in Example 1

described, using Piasite No.7111 plus about 7 1/2 wt.% Portland cement used and the mass used, to repair a degreasing system. Care must be taken to keep the cement in the container for the The mass from which the material is used remains in a finely dispersed state. If you bring the cover with care results which are very satisfactory.

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Claims (6)

- 8 claims 1. Coating composition of a film-forming resin and a hardening agent, characterized in that it contains from 5 to 50 % by weight, based on the total composition, of a cement additive which has a density such that it remains dispersed during use. 2. Composition according to claim 1, characterized in that it is an epoxy-phenolic resin, an amine curing agent and one contains refractory cement. 3. Mass according to claim 2, characterized in that Portland cement is used as cement. 4. Composition according to one of claims 1 to 3 »characterized in that it contains a fibrous material. 5. Procedures for repairing and editing and finishing of interior surfaces that are in contact with moisture and a chlorinated hydrocarbon solvent or the decomposition products of chlorinated hydrocarbon solvents, characterized in that one the coating composition according to any one of claims 1 to 4 applies and cures. 6. The method according to claim 5, characterized in that that an epoxy-amine cured base coat containing lead silicochromate and iron oxide is used as the first coat applies and then applies the coating composition according to one of claims 1 to 4 as a second coat and then hardens. 409839/091 7