JPH0432872B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for anti-icing materials, and more particularly, it relates to a composition for preventing water from freezing, which is made of an organopolysiloxane resin as a base and has an alkali metal compound and a paraffin substance uniformly dissolved or dispersed in the matrix. The present invention relates to a composition for an anti-icing material that can prevent strong adhesion to the surface of objects and has excellent durability. Conventionally, as one measure to prevent icing, attempts have been made to reduce the icing force by applying various coatings to the surface of objects. As the coating material, acrylic resin-based, rubber-based, fluororesin-based and silicone resin-based coating materials are known. Among these, various silicone-based organopolysiloxane resins are particularly widely used. For example, Soviet Patent No. 789080 discloses a two-layer silicone anti-icing paint. Further, US Pat. No. 4,271,215 discloses an anti-icing coating using a tetraalkoxytitanium compound as an adhesion catalyst to a specific silicone resin having a carboxyl functional group. Although it is possible to more or less reduce icing by coating the surface of an object with these coating compositions, strong adhesion due to hydrogen bonding of ice cannot be completely prevented. Therefore, the present inventor conducted basic research on the mechanism of icing, categorized it into three factors: interface science, physical, and thermodynamic, and found that an alkali metal compound with a hydrogen bond dissociation effect was found. We have previously proposed a composition for an anti-icing material which is composed of a combination with an organopolysiloxane resin and which exceeds the anti-icing ability of conventional coating materials (see Japanese Patent Application No. 136,570/1983). However, although the proposed composition for an anti-icing material exhibits a practically satisfactory interfacial breaking force when ice is pulled in the vertical direction at the ice-coating interface, Because some shear breaking force remains, it is not possible to completely prevent adhesion due to ice hydrogen bonding.Therefore, there is a strong demand in this field for the development of a composition for anti-icing materials with low shear breaking force at the interface. has been done. Therefore, as a result of intensive studies on a method for reducing the shear breaking force at the ice-coating film interface in the previously proposed composition for anti-icing material, the present inventor added a specific amount of paraffin substance to the composition. By doing so, it was discovered that not only the shear fracture force at the interface could be reduced, but also the sustainability of the icing prevention ability could be greatly improved, leading to the completion of the present invention. Thus, according to the present invention, (A) the following average compositional unit formula (In the formula, R represents a monovalent organic group bonded to silicon through a carbon-silicon bond, or hydrogen, and R' represents hydrogen, a _C1 - _C20 alkyl group, an acyl group, an aryl group, or an oxime residue. n and m in the above formula are each less than 4 and satisfy 0<n+m<4.) Organopolysiloxane resin 40~
99.6% by weight (B) Following formula Ma ) 0.2-30% by weight of an alkali metal compound represented by
and (C) liquid paraffin and/or solid paraffin
A composition for anti-icing material comprising 0.2 to 30% by weight is provided. The effects of the composition according to the present invention on preventing icing include the surface properties and physical properties of the organopolysiloxane resin A, which is one of the constituent components of the composition, the thermodynamic action of the alkali metal compound B, and the paraffin substance. This appears as a combined effect with the surface orientation characteristics of C, and can completely prevent icing. That is, since the organopolysiloxane resin has hydrocarbon chains arranged on its surface, its surface energy is low, and since it contains extremely few polar components that tend to form hydrogen bonds, it forms a water-repellent surface.
In addition to this low surface energy, the ability of organopolysiloxane resins to reduce icing is largely due to their physical properties, especially their low-temperature properties. That is,
The rigidity of the organopolysiloxane resin is small;
Moreover, because its glass transition temperature is low, it is extremely low temperature.
For example, its molecular motion is not frozen even under conditions of -30°C, and it exhibits extremely low rigidity, making it difficult to become a target for hydrogen bonds when frozen. Furthermore, the action of an alkali metal compound can be explained using the example of a lithium compound in an alkali metal compound.The ionic radius of Li is small (0.6
Å), therefore the hydration energy is 125Kgcalg/
Ion is large (by the way, Na is 94.6Kgcalg/Ion). Five molecules of water are adsorbed around the Li ion, and another 10 molecules of water are adsorbed on the outside, but because these water molecules are too close to the lithium ion, they have more energy than hydrogen bonds. Since it is adsorbed, no hydrogen bonds are formed. That is, the lithium compound trapped in the organopolysiloxane resin matrix does not freeze adsorbed water molecules on the surface of the coating material, so ice does not adhere to it. Although such effects have been observed with Na ions and K 2 ions, Li ions are much more effective and are more suitable. Furthermore, paraffin substance C in the present invention
The effect of this is the orientation effect on the surface, which is caused by non-polar hydrocarbon chains arranging on the surface, lowering the surface energy and at the same time imparting lubricity to the surface, which reduces shear at the ice-coating interface. Decreases destructive power. Organopolysiloxane resin A in the present invention
is the above average compositional unit formula It is represented by the following formula and can be dispersed and/or dissolved in water and an organic solvent to form a liquid. R in the above formula is a monovalent organic group bonded to silicon via a carbon-silicon bond or hydrogen. Examples of the organic group include alkyl groups such as methyl, ethyl, propyl, and hexyl; cycloalkyl groups such as cyclohexyl, cyclobutyl, and cyclopentyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; benzyl, phenylethyl, methylbenzyl, and naphthyl; Examples include aralkyl groups such as benzyl; alkenyl groups such as vinyl, allyl, and oleyl; cycloalkenyl groups such as cyclopentadienyl and 2-cyclobutenyl; and alkenylaryl groups such as vinylphenyl. Among them, lower alkyl groups having 1 to 6 carbon atoms are effective in preventing icing. In addition, in the formula, R' is not only hydrogen, but also, for example, methyl,
ethyl, propyl, butyl, amyl, hexyl,
_C1 - _C20 alkyl groups such as octyl; aryl groups; acetyl, propionyl, butyryl, etc.
Examples include a _C1 to _C8 acyl group; an oxime residue; and the like. The above-mentioned organopolysiloxane resin used in the present invention can be used without any restriction on molecular weight as long as it can be dispersed and/or dissolved in water and organic solvents as described above, but commonly used organopolysiloxane resins can be used. The number average molecular weight ranges from about 300 to about 1,000,000, preferably from about 1,000 to about 500,000. Preferably, the organopolysiloxane resin has a reactive group such as a hydroxyl group or an alkoxy group in its molecule. Examples of such organopolysiloxane resins include Z-6018 and Z-
6188, Sylkyd50, DC-3037 (Dow Corning product), KR-216, KR-218, KSP-1 (Shin-Etsu Silicone Co., Ltd. product), TSR-160, TSR-165 (Tokyo Shibaura Electric Co., Ltd. product) , SE1821, SE1980, SE9140,
Examples include SRX211, PRX305, SH237, SH9551RTV (Toray Silicone Co., Ltd. product). The amount of the organopolysiloxane resin used is 40 to 99.6% by weight, preferably 75 to 99.0% by weight. When the amount used is more than 99.6% by weight or less than 40% by weight, the icing property increases significantly. Furthermore, M in the alkali metal compound B represented by the general formula MaX used in the present invention is Li,
It is an alkali metal selected from Na and K, with Li being preferred among them. In addition, X is an inorganic acid group, a hydroxyl group, or an organic acid group, and an inorganic acid group refers to the remaining portion after removing one or more hydrogen atoms that can be substituted with a metal from an inorganic acid molecule, and includes F , Cl , Br ,
and unit atoms such as I and NO ₃ , CO ₃ ²
, PO ₄ ³ , HPO ₄ ² , SO ₄ ² , HSO ₄ ,
MnO ₄ , Cr ₂ O ₇ ² , SiO ₄ ⁴ , SiO ₃ ² BO ₂ ,
It can include atomic groups such as VO ₄ ³ , WO ₄ ² and the like. In addition, the organic acid radical refers to the remaining portion of a saturated or unsaturated monocarboxylic acid or polycarboxylic acid molecule after removing one or more hydrogen atoms that can be substituted with a metal, such as HCOO and the general formula
Saturated monocarboxylic acid group represented by CH ₈ (CH ₂ )nCOO (n: an integer from 0 to 20); general formula

[Formula] Saturated dicarboxylic acid group represented by (n: 0 to 10); Unsaturated acid group such as maleic acid, oleic acid, linoleic acid; Other tartaric acid group OOC- (CHOH) ₂ -
COO citric acid root trimellitic acid root pyromellitic acid root Examples include polyvalent carboxylic acid groups such as; Further, a is determined depending on the type of inorganic acid radical or organic acid radical, and is usually an integer of 1 to 4. Therefore, the following can be exemplified as representative examples of the alkali metal compounds represented by the above formula. LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr,
NaI, KF, KCl, KBr, KI, _LiNO3 , _NaNO3 ,
_{KNO3 , Li2CO3 , Na2CO3 , K2NO3} , _{Li3PO4 ,}
Na ₃ PO ₄ , KPO ₄ , Li ₂ SO ₄ , Na ₂ SO ₄ , K ₂ SO ₄ ;
_LiMnO4 , _NaMnO4 , _{KMnO4 , Li2Cr2O7 ,
NaCr2O7 , K2Cr2O7 , Li4SiO4 , Li2SiO3 , _}
Na ₄ SiO ₄ , Na ₂ SiO ₃ , K ₄ SiO ₄ , K ₂ SiO ₃ , LiBO ₂ ,
NaBO ₂ , KBO ₂ , Li ₃ VO ₄ , Na ₃ VO ₄ , K ₃ VO ₄ ,
Li ₂ WO ₄ , Na ₂ WO ₄ , K ₂ WO ₄ ;HCOOLi,
HCOONa, HCCOK, Li ₂ C ₂ O ₄ , Na ₂ C ₂ O ₄ ,
K ₂ C ₂ O ₄ , CH ₃ COOLi, CH ₈ COONa,
CH ₃ COOK, C ₂ H ₅ COOLi, LiOOC−CH ₂ −
COOLi, lithium citrate, sodium citrate, potassium citrate, lithium tartrate, lithium trimellitate, lithium pyromellitate, etc. Among these alkali metal compounds, chloride has the greatest anti-icing effect. However, when such strong acid salts are used, they have the property of causing rust on metal materials, so care must be taken when using them. Next, carbonates, silicates, and acetates have the greatest anti-icing effect, and these are preferable because they have a long-lasting anti-icing effect and are less likely to cause rust. Further, among these alkali metal compounds, lithium compounds are preferred because they have a greater anti-icing effect than other sodium compounds and potassium compounds. These alkali metal compounds can be used alone or in combination of two or more, and the amount thereof is 0.2 to 30% by weight, preferably 0.5 to 10% by weight. If the amount of the alkali metal compound is less than 0.2% by weight, the anti-icing effect will be significantly reduced, and if it exceeds 30% by weight, the physical properties of the coating will deteriorate and it will not be able to withstand long-term use. Further, the paraffin substance C used in the present invention is a conventionally known liquid paraffin and solid paraffin, and the former liquid paraffin is mainly composed of hydrocarbons having 10 to 24 carbon atoms, has an average molecular weight of about 150 to 250, and has an average molecular weight of about 150 to 250. It is liquid and is commonly referred to as white oil. On the other hand, the latter solid paraffin is mainly composed of hydrocarbons having about 18 to 30 carbon atoms, has an average molecular weight of about 250 to 350, and has a melting point of 50°C or less, preferably 40°C.
It is a substance that can be dissolved or dispersed in the following solid organic solvents at room temperature. In the present invention, liquid paraffin is used, especially at pour point (Pour point).
Liquid paraffin with a low temperature (point) of −5° C. or lower is preferred because it maintains fluidity even at temperatures below the freezing point and is extremely effective in reducing shear breaking force. Typical examples of paraffin include liquid paraffin with the trade name “Carnation”;
Examples of solid paraffins include "Kloarol", "Blandol", "Benol", Kaydol, etc. (products of Witco Chemical Co., Ltd. in the United States), while solid paraffins include paraffin waxes 110, 115, and 120 manufactured by Nippon Seimo Co., Ltd. . The blending amount of these paraffin substances C is 0.2 to 30% by weight, preferably 0.5 to 15% by weight. When the content of the paraffin substance is less than 0.2% by weight, no decrease in shear breaking force at the ice-paint interface is observed;
If it exceeds 30% by weight, the physical properties and durability of the coating film will deteriorate. In producing the composition of the present invention, the organopolysiloxane resin, alkali metal compound, and paraffin material are mixed using a steel pole mill, a pebble mill, an attritor, etc., which are common dispersion methods. When preparing a composition for use as a paint, an organic solvent is appropriately used. The solvent may be any solvent as long as it can dissolve the organopolysiloxane resin as the base resin, and for example, solvents commonly used in paints such as chain or cyclic hydrocarbons, ketones, esters, and alcohols can be used. Water is naturally used when the paint is a water dispersion system. In addition to being applied as a top coat on top of a base coat, the composition can also be applied to metals, plastics, glass,
It is possible to apply directly to wood materials, etc. The composition can also be used as a molded product by being laminated onto the surface of an object, and if necessary, pigments, extender pigments, or dyes can be added to the composition as component A and component B.
It can be added in an amount of up to 120 parts by weight based on 100 parts by weight of the total amount of component C. Other surfactants and additives can also be added as appropriate. Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts and percentages are by weight unless otherwise specified. Example 1 Addition polymerization type organopolysiloxane resin (trade name: Toray Silicone SE-1821, non-volatile content 40%)
100 parts, 2 parts of lithium acetate and Kaydol (trade name:
0.5 part of liquid paraffin, manufactured by Witco Chemical (USA), pour point -18°C) was added to a Red Devil type paint conditioner together with alumina silicate beads having a diameter of 3 mm, and dispersed for 30 minutes. Next, 10 parts of SE-1821 Cat (manufactured by Toray Silicone Co., Ltd., platinum-based catalyst) was added as a hardening agent, and the resulting composition was applied onto a stainless steel plate for icing tests using an applicator.
Baking was performed at 100°C for 5 minutes. The dry coating thickness at this time was 12 μm. −10℃ according to the test method described below.
The icing shear fracture strength was measured after freezing for 2 hours. As a comparative example, the icing shear fracture strength was also measured under the same conditions for a composition prepared in the same manner as in Example 1 (Comparative Example 1) except that liquid paraffin was not used. The results of these tests are shown below.

[Table] Example 2 Addition polymerization type organopolysiloxane resin (product name: Toray Silicone SRX-211, non-volatile content 40%,
(number average molecular weight approximately 300,000 or more) 100 parts, lithium chloride
0.5 parts and Carnation (Product name: Witco USA)
Chemical liquid paraffin, pour point -7℃)
10 parts were dispersed in the same manner as in Example 1. Next, a composition obtained by adding 0.6 parts of a platinum-based catalyst SRX-212 Cat (manufactured by Toray Silicone Co., Ltd.) to this material was applied in the same manner as in Example 1, and heated at 150°C for 3 minutes.
A dry coating film of 20 μm was obtained. The icing shear fracture strength when frozen at -10°C for 2 hours was measured using the test method described below. As a comparative example, the icing shear fracture strength was also measured under the same conditions for a composition prepared in the same manner as in Example 2 (Comparative Example 2) except that liquid paraffin was not used. The results of these tests are shown below.

[Table] Example 3 Polycondensation type organopolysiloxane resin (Product name: Toray Silicone SE-9140, non-volatile content 40%)
100 parts of potassium carbonate, 4 parts of potassium carbonate, and 2.0 parts of the liquid paraffin used in Example 1 were dispersed and coated in the same manner as in Example 1, and dried at room temperature for 48 hours.
The dry coating film at this time was 7 μm. -10℃2
The icing shear fracture strength was measured when frozen for a time. As a comparative example, the icing shear fracture strength was also measured under the same conditions for a composition prepared in the same manner as in Example 3 (Comparative Example 3) except that liquid paraffin was not used. The results of these tests are shown below.

[Table] Example 4 Instead of 0.5 part of Kaydol in Example 1, SP
A paint was prepared in the same manner as in Example 1 except that 5 parts of 10% toluene solution of Nippon Seimosha refined solid paraffin (trade name) was used, and the paint was subjected to an icing shear failure test. The test results are shown below.

[Table] Icing shear fracture strength test method: A stainless steel ring 3 (inner area 5 cm ² ), place it in a -10°C freezing test constant temperature bath, and pre-cool it for 90 minutes. Next, 2 ml of distilled deionized water maintained at 5° C. is poured into the ring 3 and frozen, thereby obtaining ice 4 adhering to the surface of the subject.
After being left in this state for 2 hours at -10°C, the ice 4 is peeled off by impacting the ring 3 with a metal moving rod (shaft) 5 connected to a load cell (not shown) and driven by power. The shear fracture strength was measured (unit: Kg/cm ² ).

[Brief explanation of drawings]

FIG. 1 is a sectional view of an apparatus for testing the icing properties of the composition for anti-icing materials of the present invention. 1...Stainless steel lithographic plate, 2...Coating film, 3...
Stainless steel ring, 4...ice, 5...operating rod.

Claims (1)

[Claims] 1 (A) The following average compositional unit formula (In the formula, R represents a monovalent organic group bonded to silicon through a carbon-silicon bond, or hydrogen,
R′ is hydrogen, C ₁ to C ₂₀ alkyl group, acyl group,
Indicates an aryl group or an oxime residue. n and m in the above formula each have a value less than 4, and 0<n
This value satisfies +m<4. ) Organopolysiloxane resin 40~
99.6% by weight (B) Following formula Ma ) 0.2-30% by weight of an alkali metal compound represented by
and (C) liquid paraffin and/or solid paraffin
A composition for anti-icing material consisting of 0.2 to 30% by weight. 2. The composition for an anti-icing material as defined in claim 1, wherein the alkali metal compound is a lithium compound.