DE3238039C2 - - Google Patents

Description

The invention relates to agents for Unterbin formation of ice on the surface of a counter state that is exposed to icing conditions.

The freezing of the water is caused by the formation of what hydrogen bonds of the water molecules at low temperatures caused temperatures below 0 ° C, which is a very high Ko adhesion results. For the destruction of so related Theoretically, molecules will have a surface pressure of 10,000 kg / cm² assumed, while the measured area pressure is 16 to 80 kg / cm². Ice sticks to the Surface of an object through the hydrogen bridge between the water and the surface an enormous adhesion. Frost and icing damage occur in cold climates and during winter in different parts of the world. The much severe risks from frost and icing also those at sea and in aviation by Ver Freezing of watercraft and planes, paralysis rail traffic through icy railways, Interruption of traffic through icy roads and the related accidents, as well as the one falling from houses, the interruption of energy Transmission lines and interference on transmit and Reception systems due to snowfall. Above all, at Ships that cause ice formation can cause fatal accidents the ice moves the ship's center of gravity upwards can store, in such a way that the ship capsizes.  Generally, funds are strewn on the streets that protect the streets from freezing.

For example, at least annually in the United States 10 million tons used, causing rusting on the motor vehicles and on pollution of the groundwater, and damage in the amount of Caused $ 100 million.

With a view to a possible exhaustion of the world Oil reserves have been in the North in recent years see new oil fields opened up. There is a Be may de-icing agents necessary for the expansion of the oil holes can be used so that the For was intensified, effective deicing agents to provide.

The previous attempts, the formation of ice on the Surface of an object by applying a To prevent coating composition, the Icing susceptibility reduced. Acquaintances, for coating compositions used for this purpose mainly include acrylic resin, rubber, fluorine Compositions containing resins, silicone resins, etc. Among these, organopolysiloxane resin is a genus the silicone resins, which are used from time to time came. For example, in "Chemical Abstracts, Vol. 93, 134009P "a coating composition of Silicone genus for the prevention of ice formation described, which is applied in two layers. Fer ner U.S. Patent No. 4,271,215 discloses a Be Layer composition for dissolving ice, which carboxy-functional siloxane and a tetraalkoxy Contains titanium compound.  

The one with the known coating compositions created coatings show a more or less reduced susceptibility to icing, can ever but the formation of ice with high adhesion hydrogen bonding, not complete exclude. There are therefore further improvements required.

The object of the invention is the sheep anti-icing agent, which mainly contains organopolysiloxane resin and exceptional protective properties against ver shows ice.

The object of the invention is achieved by a means for Prevention of ice formation solved, the characteristic net is due to the content of anti-icing material, the

• (A) from 70 to 99.8% by weight of an organosiloxane compound with a numerical average molecular weight of 300 to 1,000,000 and with structural units of the formula wherein R is a hydrogen atom, an alkyl group with 1 to 6 carbon atoms or a vinyl group, R 'is a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, a phenyl group, a phenyl group substituted by methyl or ethyl groups, a naphthyl group, one by methyl or Ethyl groups substituted naphthyl group or the grouping and n and m each represent an integer from 0 to 3 and n plus m is an integer from 0 to 3,
• (B) from 0.2 to 30% by weight of an alkali compound Alkali chlorides, carbonates, silicates, ace deeds, citrates and / or oxalates, the Alkali metal is Li, Na and / or K, as well as usual additives.

Basic research has been done on the Mechanism of icing carried out, the pheno of icing in terms of three factors was examined scientifically, namely with regard to the Surface behavior, the physical and the thermo dynamic factors. It was found that whether probably an organopolysiloxane resin of lower susceptibility for icing than any other resin shows when using an organopolysiloxane resin this alone to Be leads to stratifications that significantly increase ice formation lying there. Further investigations showed that a ver almost completely through synergistic effect is prevented when certain organopolysiloxane compounds in combination with an alkali compound be used. Based on these findings the present invention.

The agent according to the invention enables a complete Prevention of ice formation through the function of two components, namely the effect due to  Interface properties and physical Properties of the organopolysiloxane compound (A), combined with the thermodynamic function of the Alkaline compound (B).

The organopolysiloxane resin has a chain from Koh Hydrogen groups, indicated on its surface orders, and consequently it has low waiters surface energy. Furthermore, this resin contains only one small amount of polar components that make up the bil tend to form hydrogen bonds. With such Properties (A) are known per se and finds various uses as one material for water-repellent surfaces. The ability of Compound (A), susceptibility to icing too decrease, is largely due to the physi properties of this compound at low Temperatures, in addition to low surfaces energy of the same, derived. The resin (A) has a low stability (bending strength) and has a low glass transition temperature. Therefore especially at extremely low temperatures, e.g. B. at -30 ° C, the mobility of the resin molecules not below broken, so that this factor, coupled with the ge wrestle stability, in a lower probability The result is that resin molecules from water moles cool for the formation of hydrogen bonds can be caught.

The susceptibility of the coating to icing depends on the flow behavior of the coating in a low temperature zone as well as the Eigen  remove the surface of the coating. The according to the accessibility of the Be varies Layering for icing with the thickness of the loading layering. So is z. B. the adhesion between Ice and coating 0.3 to 1.2 kg / cm² at one Coating thickness from 50 to 200 µm at -25 ° C, while the ice adheres to the coating with a coating thickness of 5 to 10 µm 1.0 to 2.4 kg / cm² increases. But if, for example 3 parts of an alkali compound 100 parts of Har zes (A) are added, the adhesion becomes zero, even with a coating thickness of 5 to 10 µm.

This mechanism is discussed below Use a lithium compound, as an example of alkali compounds, be wrote. The ion or Li⊕ has a small one Radius (0.6 Å) so that the hydration energy in of the order of 125 kg cal g / ion (the the Na is 94.6 kg cal g / ion). Five water molecules are adsorbed by the Li⊕ ion, and 10 water molecules are ad on the surface of the 5 water molecules sorbed. These water molecules do not contribute to the bil formation of hydrogen bonds, since the molecules are arranged near the lithium ion and by a more energy is adsorbed than by water fabric bridges. That in the matrix of organopolysiloxane resin inserted lithium compound does not allow the Solidification of the surface of the coating ad sorbed water molecules and thus makes none possible Ice formation. Similar effects are observed with the Na⊕ ion and K⊕ ion achieved, but less effectively than with  the Li⊕ ion, which is therefore for the ver is cheaper.

The organopolysiloxane compound (A) of the invention is by the following structural formula

shown, and can be in water or an organi dispersed and / or dissolved solvent the one that takes on a liquid form.

R in this formula represents a hydrogen atom, a Alkyl group with 1 to 6 carbon atoms or one Vinyl group as a monovalent organic group, the to the silicon atom through a carbon / silicon Bond is bound.

Examples of organic groups of the radical R are Methyl, ethyl, propyl, hexyl, as well as vinyl groups.

R 'represents a hydrogen atom in the structural formula and groups such as methyl, ethyl, propyl, butyl, Amyl, hexyl, octyl and similar alkyl groups with 1 to 20 carbon atoms, oxime radicals of the formula

substituted with methyl or ethyl groups or unsubstituted phenyl groups and with methyl or ethyl groups substituted or unsubstituted Naphthyl groups. Specific examples include phenyl,  Tolyl, xylyl, naphthyl.

The organopolysiloxane used according to the invention has a numerical average molecular weight from about 300 to about 1,000,000, preferably about 1000 to about 500,000 and is in water and egg nem organic solvent dispersible and / or soluble. The use of the organopolysiloxanehar zes with reactive groups such as hydroxyl groups or alkoxy groups is preferred. Examples of the are like organopolysiloxane resins

Typical curing mechanisms for organopolysiloxane resins are those of (I) condensation polymerization type and that of the (II) addition polymerization type, as this is shown schematically below:  

(I) type of condensation polymerization

(II) Type of addition polymerization

In the above reaction equations, R and R 'are like defined above.

The susceptibility of the coating to ver Icing is noticeably increased when the present Zu composition organopolysiloxane resin in a lot of more than 99.8% by weight or less than 70% by weight contains.

The alkali compound (B) consists of alkali chlorides, carbonates, silicates, acetates, citrates and / or oxalates, the alkali metal being Li, Na and / or K.  

Li is the most suitable. The anorga African acid group of the compound mentioned under (B) dung means a part that remains after at least one hydrogen atom, substitutable with metal, the molecule of the inorganic acid group pe is withdrawn. Examples include:

Cl⊖ and the atomic groups such as CO₃²⊖, SiO₄⁴⊖ and SiO₃²⊖.

The organic acid group of those mentioned under (B) Connections means a part that remains after at least one of the hydrogen atoms, sub can be constituted with metal, the molecule of the mentioned ge saturated monocarboxylic acid or polycarboxylic acid ent is moved. Examples of such acid groups are:

CH₃COO⊖ and the citric acid group of the formula

Examples of suitable alkali compounds are:

LiCl, NaCl, KCl, Li₂CO₃, Na₂CO₃, Li₄SiO₄, Li₂SiO₃, Na₄SiO₄, Na₂SiO₃, K₄SiO₄, K₂SiO₃, Li₂C₂O₄, Na₂C₂O₄, K₂C₂O₄, CH₃COOLi, CH₃COONa, CH₃COOK, Lithium citrate, sodium citrate, potassium citrate.

Chlorides are among these alkali compounds most effective for connecting ice formation. It is however, when using salts of strong acids Caution should be exercised as these may be on the generate rust. Carbonates, silicates and acetates are in their preventive effect ice formation next to the chlorides and are better suitable because they form ice over a longer period Prevent period and probability of Generation of rust is less. Of these alkali compounds are lithium compounds for ver prevent icing of the sodium compounds and superior to potassium compounds and therefore for the intended use more appropriate.

The alkali compounds are individually or in mixtures usable. The compound is used in an amount of 0.2 to 30% by weight, preferably 0.5 to 10% by weight rend on the present composition used. With less than 0.2 wt .-% of the alkali compound results a reduced effect in terms of prevention icing while using this icing binding in an amount of more than 30 wt .-% the phy sical properties and durability (duration adhesion) of the coating are impaired and also the susceptibility of the coating to Icing is increased.

The present remedy is produced by the Orga nopolysiloxane compound and the alkali compound the usual way using a steel ball mill, ball mill or friction mill  to be mixed. A suitable solvent added to the present composition Adapt the intended use of the coating. A can be used solvents that the Organopolysilo Disconnect xan connection. A large selection of over Licher for the production of coating compositions usable solvents are used like benzene, toluene, xylene, Cyclohexane, hexane, heptane, octane and similar linear or cyclic hydrocarbons, methyl ethyl ketone, Methyl isobutyl ketone, acetone and similar ketone Ge solvent, methyl alcohol, ethyl alcohol, pro pyl alcohol and similar alcohol-containing solvents. Water is used as a solvent in the manufacture water soluble coating compositions ver turns. The solvent is usually in a Amount from 0 to 500 parts by weight, preferably Calculate 20 to 80 parts by weight per 100 parts th combined amount of components (A) and (B) used. The means thus produced is called a deck layer over a primer or directly on top of it Surface of the material, such as metal, plastic, glass or Applied wood. The present composition can be pressed into strips of film, which then layer wisely applied to the surface of the object and can, if necessary, be a color pigment, such as titanium oxide, carbon black, iron oxide, phthalocyanine blue, an extender pigment such as calcium carbonate, barium sulfate, talc, barite or a dye in one Amount up to 120 parts by weight per 100 parts of it calculated combined amount of components (A) and (B) included. A surfactant and  other additives can also be found in the present Be Layer composition can be included.

The present invention is now described in detail by the examples, the details of the proportions and percentages, unless stated otherwise, always refer to the weight in the description. The tests of the susceptibility of the coating to icing were carried out as described below using the device shown in FIG. 1.

The device shown has a container 2 made of foamed styrene, the interior of which is lined with copper sheet 1 . A stainless steel plate 3 (dimensions 100 × 100 × 100 mm) with a coating of the present coating composition was placed in the container 2 . A connector part 5 with a flat bottom piece of stainless steel was placed on the coating 4 , which covered an area of 31.17 cm², such that water as an intermediate layer 6 of 5 to 10 microns thick between the bottom of the connector partly 5 and the coating 4 was present. The device thus arranged was housed in a freezer chamber and left therein for 5 to 72 hours at -20 to -30 ° C. Thereafter, the connector 5 was moved by an adhesion tester 7 in the freezer to move up to the boundary layer separation strength (kg / cm²) at the interfaces between the ice and the coating by means of a measuring cylinder 9 . In this arrangement, 8 with a supporting element, 10 with a coil spring and 11 with a rubber pack.

Example 1

The amount of 100 parts of organopolysiloxane resin of the addition polymerization type of the formula

(SE-1821, 40% non-volatile inventory parts) and 2 parts of lithium acetate were together with Aluminum silicate beads, 5 mm in diameter, in egg Given a color conditioning apparatus and 30 Mi grooves dispersed. Then 10 parts of a Kataly platinum type as a hardener of the Dispersion for the preparation of the coating together settlement added. The coating thus produced composition was then made through an order device on the surface of a copper plate for the Icing test applied and at 100 ° C for 5 minutes branded. The coating so applied had a thickness of 12 µm in the dried state. The coated plate then became iced Exposed to -29 ° C for 16 hours and after the above be described method for determining the adhesion of the Ice on the surface of the copper plate (hereinafter labeled with icing adhesive strength).  

Tests for Er averaging of the icing adhesive strength among the same conditions as above using (I) one made in the same manner as above coating composition, with the exception that lithium acetate was not used (comparative Example 1-1), (II) one in the same way as coating composition prepared above, with the exception that barium sulfate is in the same menu was used instead of the lithium acetate (Comparative Example 1-2), and (III) a Teflon resin (polytetrafluoroethylene) layer, which in a Thickness of 2 mm thermally using a press the surface of the copper plate was applied (Comparative Example 1-3).

Table 1 shows the test results:

Table 1

Example 2

A lot of 100 parts of organopolysiloxane resin Addition polymerization type of formula

(Designation SRX-211, 40% heavy-liquid-volatile stock divide with an average numerical mole specular weight over 300,000) and 0.5 parts lithium Chloride was made in the same manner as in Example 1 dispersed. 0.6 parts of a platinum catalyst were used to make the coating together settlement added. The coating thus produced composition was the same as in Example 1 che on a copper plate of the same type wear, and then the coated plate at 150 ° C. for 3 minutes to form a coating with 20 µm thick heated in the dried state. The be layered plate was made using the same method as described above for icing adhesion after ver. at -25 ° C for 44 hours exposed to ice.

For comparison purposes, tests were also carried out on the festival position of the icing adhesion under densel ben, conditions listed in Example 1 performs by (I) a coating composition was used, which according to Example 2, except that lithium chloride was not used was (Comparative Example 2-1), (II) Be Layer composition was used in the same way as in Example 1 except was placed that calcium chloride in the same amount  was used instead of lithium chloride (Comparative Example 2-2), and (III) a Teflon Resin layer adheres thermally by pressing on the surface of the copper plate with formation a layer thickness of 2 mm was applied (Comparative Example 2-3). Table 2 shows the Test results:

Table 2

Example 3

A lot of 100 parts of organopolysiloxane resin from Condensation polymerization type of the formula

(Designation SE-9140, 40% difficult-volatile ingredients) and 4 parts of potassium carbonate were as dispersed in Example 1 and the Be Layer composition as in Example 1 wear. The coated plate was at room temperature  ratured for 48 hours, creating a coating with a thickness of 7 µm when dry. The Icing adhesive strength of the coated plate was measured after the plate at -20 ° C for 5 hours who was exposed to icing.

For comparison purposes, tests to determine the Icing adhesive strength among the be in Example 1 conditions described, a Be layering composition was used, which on the same way as in Example 3 except was made that potassium carbonate was not used (Comparative Example 3-1), and a Teflon resin layer adheres to the surface by pressing surface of the copper plate to form a layer thickness of 2 mm was applied (comparative example 3-2). Table 3 shows the test results:

Table 3

Example 4

A lot of 100 parts of organopolysiloxane resin from Condensation polymerization type of the formula

(Description PRX-305, 40% heavy-cursed components, with a numerical mean Molecular weight over 300,000) and 1.0 part of lithium Citrates were made in the same manner as in Example 1 dispersed. The coating so prepared together was placed as in Example 1 on a copper plate applied. The coated plate was left in the room for 24 hours temperature kept, whereby a dried Be Layering of 30 microns was formed. The plate was exposed to icing at -20 ° C for 5 hours and tested the icing strength.

For comparison purposes, two copper plates of the in the manner described in Example 1 as in Example 1 with a coating setting as in Example 1, except that none Lithium citrate was used, coated (Ver same example 4-1), and a Teflon resin layer thermally adhering to the surface by pressing the copper plate to form a layer thickness of 2 mm was applied to the plate (comparative example 4-2). The plates were then placed on icing Adhesion tested. Table 4 shows the tests Results:  

Table 4

Example 5

A lot of 100 parts of organopolysiloxane resin from Condensation polymerization type of the formula

(Designation SH-237, 40% heavy volatile components, with a numerical mean ren molecular weight of about 17,000), 2.5 parts Lithium oxalate and 40 parts of titanium dioxide became disperous giert, applied and at 50 ° C for 5 hours Formation of a layer with a thickness of 15 µm dried. After the coated plate for Exposed to icing at -26 ° C for 22 hours, was tested for icing strength.

For comparison, the icing strength was un ter measured under the conditions shown in Example 1 sen, the same copper plates as in Bei game 1 were used with a coating  composition coated on the same Way as in Example 1, except that no lithium oxalate was used (comparative Example 5-1) and a Teflon resin layer by Auf press thermally adhering to the surface under Bil a layer thickness of 2 mm was applied (Comparative Example 5-2). The test results are out Table 5 can be seen.

Table 5

Example 6

An amount of 100 parts of an aqueous solution Organopolysiloxane resin from addition polymerization type of formula

(Designation SH-9555 / RTV, 45% low volatility ingredients) and 1.2 parts of sodium chloride dispersed as applied in Example 1 and at room temperature left for 48 hours and 3 hours  at 50 ° C to form a coating with 30 µm Thickness dried. The icing strength of the coated plate became iced after 5 hours measured at -20 ° C.

For comparison, copper plates as described in Bei game 1 were used with a coating composition coated in the same way as in Example 1, except that no sodium chloride was used was produced (comparative Example 6-1) and a Teflon resin layer by Auf press thermally adhesive to form a layer thickness of 2 mm applied (Comparative Example 6-2). The coated panels were ice-locked festigksleit checked; the test results are from Ta belle 6 can be seen:

Table 6

Example 7

A lot of 100 parts of organopolysiloxane resin from Condensation polymerization type of the formula  

(Designation SE-1980, 100% non-volatile Components) and 10 parts of lithium carbonate dispersed as in Example 1. The dispersion was 10 parts of a platinum-type catalyst (the same as in Example 1) while stirring. The so forth provided coating composition became a Shaped layer of uniform thickness of 2 mm, the one flat surface over a substrate surface for the Ver had ice test. The layer was at normal temperature dried for 48 hours and the icing -29 ° C for 18 hours exposed to the icing Measure adhesive strength.

For comparison, the icing adhesive strength was un ter the same conditions as in Example 1, with Be tensile to the copper plates measured according to Example 1, which is coated with a coating composition were as in Example 1, except that Li thium carbonate was not used (Comparative Example 7-1), and a Teflon resin layer with a layer thickness of 2 mm thermal adhered pressed (Comparative Example 7-2).  The test results are shown in Table 7.

Table 7

Claims (2)

1. Means for connecting the formation of ice, characterized by a content of anti-icing material, the

• (A) from 70 to 99.8% by weight of an organosiloxane compound with a numerical average molecular weight of 300 to 1,000,000 and with structural units of the formula wherein R is a hydrogen atom, an alkyl group with 1 to 6 carbon atoms or a vinyl group, R 'is a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, a phenyl group, a phenyl group substituted by methyl or ethyl groups, a naphthyl group, one by methyl or ethyl groups substituted naphthyl group or the grouping and n and m each represent an integer from 0 to 3 and n plus m is an integer from 0 to 3,
• (B) from 0.2 to 30% by weight of an alkali compound, from alkali chlorides, carbonates, silicates, acates, citrates and / or oxalates, the alkali metal being Li, Na and / or K , as well as usual additives.

2. Composition according to claim 1, characterized ge indicates that the alkali compound is a lithium salt.