JPS6362556B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for anti-icing materials, and more specifically, the present invention relates to a composition for anti-icing materials, and more specifically, by coating the surface of an object with a material based on an organopolysiloxane resin and having an alkali metal compound uniformly dissolved or dispersed in the matrix, silicone The present invention relates to a composition for an anti-icing material that can prevent water from strongly adhering to the surface of an object when it freezes due to the synergistic effect of the anti-icing effects of a resin and an alkali metal compound. The freezing phenomenon of water is due to the formation of hydrogen bonds between water molecules at low temperatures and exhibits a very large cohesive force.
The theoretical cohesive failure strength is said to be 10,000 Kg/cm ² , but in reality it has been measured to be 16 to 80 Kg/cm ² . The icing phenomenon occurs when hydrogen bonds are formed between water and the surface of an object, and exhibit extremely strong adhesion. Damage caused by icing and freezing occurs everywhere in cold regions and during the winter. For example, there are many dangers such as the danger of ice accretion on ships and aircraft, the danger of vehicles being unable to operate and accidents due to frozen roads and railways, the power lines being cut due to snow accumulation, houses collapsing, and transmitter/receiver malfunctions. Ice buildup on ships is the most dangerous, as ice buildup on the ship's hull raises the center of gravity, leading to capsizing accidents. Many lives are lost every year because of this. In addition, antifreeze agents are sprayed to prevent roads from freezing, but in the United States, for example, the amount of antifreeze used reaches 10 million tons per year, and the resulting damage from vehicle rust and groundwater contamination is estimated to be over $100 million. It is said. In addition, research and development of these materials has become active in conjunction with the need for anti-icing materials for the development of oil fields in the North Sea, which has become more active in recent years due to the depletion of oil resources. 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. 739080 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 objects with these paint compositions, it is not possible to completely prevent strong adhesion caused by hydrogen bonds in ice, and further improvements are desired. It is rare. The inventor conducted basic research on the mechanism of icing and classified it into three factors: interface science, physical, and thermodynamic. As a result, silicone polymers have a higher icing property than any other polymer. Although it is low, it was confirmed that this polymer alone has a considerable adhesion force to ice regardless of its type, and as a result of further intensive research, it was discovered that an alkali metal compound and a silicone resin that have a hydrogen bond dissociation effect were used. They discovered that icing can be completely prevented only by a synergistic effect in combination with the above, and have completed the present invention. Thus, according to the present invention, (A) the following unit formula (wherein R represents a monovalent organic group or hydrogen bonded to silicon through a carbon-silicon bond,
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 of 4 or less, and n+m
is less than 4) Organopolysiloxane resin 70~
99.8% by weight and (B) the following formula Ma There is provided a composition for an anti-icing material comprising 0.2 to 30% by weight of an alkali metal compound represented by: The effect of the composition according to the present invention on preventing icing is due to the surface properties and physical properties of the organopolysiloxane resin (A), which is one of the constituent components of the composition, and the alkali metal compound, which is the other constituent component. This appears as a combined effect with the thermodynamic effect of (B), and can completely prevent icing. In other words, organopolysiloxane resin has hydrocarbon chains arranged on its surface, so its surface energy is low, and it also has very few polar components that tend to form hydrogen bonds, so it can be used for various purposes as a material for forming water-repellent surfaces. It is well known that this is the case. 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. In other words, the rigidity of the organopolysiloxane resin is small, and its glass transition temperature is low, so its molecular motion is not frozen even under extremely low temperatures, for example -30°C. Less likely to be a target for hydrogen bonding. In this way, the icing ability is influenced not only by the surface properties of the coating film but also by the viscoelasticity of the bulk at low temperatures, so the icing ability also changes depending on the film thickness of the coating. . For example, with a film thickness of 50 to 200μm, the adhesive strength at -25℃ is 1.2 to 0.3Kg/ ^cm2 , but 5 to
For a 10 μm thin film, it increases to 1.0 to 2.4 Kg/cm ² . Therefore, when an alkali metal compound, for example 3PHR, is added to the organopolysiloxane resin, the
Even with a thin film of , the ice adhesion force is 0. To explain this mechanism using a lithium compound among alkali metal compounds as an example, the ionic radius of Li is small (0.6 Å), and therefore the hydration energy is large at 125 Kgcal g/Ion (by the way, Na
is 94.6Kgcal g/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 water molecules adsorbed on the surface of the coating material, so ice does not adhere to it. Although this effect is also seen with Na ions and K 2 ions, Li ions have a much greater effect and are more suitable. Organopolysiloxane resin (A) in the present invention
is the above unit formula It is represented by the following formula, and can be dispersed and/or dissolved in water and organic solvents to form a liquid state. 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; _C1 such as acetyl, propionyl, butyryl
~ _C8 acyl group; 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). Typical curing mechanisms of organopolysiloxane resins are the condensation type shown in () and the addition reaction type shown in (). Addition polymerization type or In the above reaction formula, R and R' are the same as described above. When the amount of organopolysiloxane resin in the composition exceeds 99.8% or is less than 70% (parts by weight), the icing property increases significantly. On the other hand, M in the alkali metal compound (B) represented by the general formula MaX in the composition 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 part 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 monatomic atoms such as I and NO ₃ , CO ₃ ² ,
_{PO43 , HPO42} , _SO42 ^{, HSO4} _, ^MnO4
_{, Cr2O72 , SiO44} , ^{SiO32 , BO2} _,
Groups such as VO ₄ ³ , WO ₄ ² and the like can be included. 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 ₃ (CH ₂ ) nCOO (n: an integer from 0 to 20); general formula

[Formula] Saturated dicarboxylic acid group represented by (n: 0-10); Unsaturated acid group such as maleic acid, oleic acid, linoleic acid; other tartaric acid group OOC-(CHOH) ₂
−COO citric acid root

[Formula] trimellitic acid radical 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 ,}
Na ₂ Cr ₂ O ₇ , K ₂ Cr ₂ O ₇ , Li ₄ SiO ₄ , Li ₂ SiO ₃ ,
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, HCOOK, Li ₂ C ₂ O ₄ , Na ₂ C ₂ O ₄ ,
K ₂ C ₂ O ₄ , CH ₃ COOLi, CH ₃ 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. Furthermore, 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 blending amount 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. In producing the composition of the present invention, the organopolysiloxane resin and the alkali metal compound are mixed using a steel ball mill, a peplum mill, an attritor, etc., which are common dispersion methods. When preparing the composition for use as a paint, a 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 by laminating it on the surface of an object as a molded product, and if necessary, pigments, extender pigments, or dyes can be added to the composition as components (A) and (B).
It can be added in an amount of 120 parts by weight or less per 100 parts by weight of the total amount. Other surfactants and additives can also be added as appropriate. The icing property test was conducted by placing a 100 x 100 x 10 mm stainless steel coated plate 3 coated with the composition of the present invention in a Styrofoam container 2 lined with a copper plate 1 as shown in Figure 1. An adhesive terminal 5 having a flat bottom made of stainless steel is placed on the membrane 4 on the area to be adhered.
A thin layer 6 of 5 to 10 μm of water is sandwiched between ^the adhesive terminal and the coating film, and the film is left in a freezer at -20 to -30°C for 5 to 72 hours. Next, the adhesive terminal was pulled upward in a freezer using an adhesive tester 7 manufactured by Elcometer (UK), and the interfacial breaking force at the ice-paint interface was measured using a measuring tube 9 (unit: Kg/cm ^{2 )} . ). 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 and 2 parts of lithium acetate were added to a Red Devil type paint conditioner along with 5 mm diameter alumina silicate beads and allowed to disperse for 30 minutes. Then,
To this, 10 parts of SE-1821Cat (manufactured by Toray Silicone Co., Ltd., platinum-based catalyst) was added as a hardening agent, and the resulting composition was applied with an applicator onto a special copper plate for icing tests, and baked at 100°C for 5 minutes. . The dry coating thickness at this time was 12 μm. The icing strength was measured when frozen at -29°C for 16 hours using the test method described above. As a comparative example, a composition prepared in the same manner as in Example 1 was used except that lithium acetate was not used (Comparative Example 1-1), and a composition was used except that the same amount of barium sulfate was used instead of lithium acetate. Also for those using a composition prepared in the same manner as in Example 1 (Comparative Example 1-2) and those using Teflon resin (polytetrafluoroethylene) crimped to a thickness of 2 mm (Comparative Example 1-3). Icing strength was measured under similar conditions. 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 and lithium chloride
0.5 parts were dispersed in the same manner as in Example 1. Next, a composition obtained by adding 0.6 parts of platinum catalyst SRX-212Cat (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 strength was measured when frozen at -25°C for 44 hours using the test method described above. As a comparative example, a composition prepared in the same manner as in Example 2 was used except that lithium chloride was not used (Comparative Example 2-1), and a composition was used except that the same amount of calcium chloride was used instead of lithium chloride. Icing was also achieved under the same conditions for a product using a composition prepared in the same manner as in Example 1 (Comparative Example 2-2) and a product using a Teflon resin crimped to a thickness of 2 mm (Comparative Example 2-3). The strength was measured. 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 and 4 parts of potassium carbonate 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. -20℃
The icing strength was measured after freezing for 5 hours. Comparative examples include one using a composition prepared in the same manner as in Example 3 except that potassium carbonate was not used (Comparative Example 3-1), and one using a composition prepared by pressing Teflon resin to a thickness of 2 mm (Comparative Example 3-1). Regarding 3-2), the icing strength was also measured under the same conditions. The results of these tests are shown below.

[Table] Example 4 Polycondensation type organopolysiloxane resin (product name: Toray Silicone PRX-305, non-volatile content 40%,
100 parts (number average molecular weight approximately 300,000) and lithium citrate
1.0 part was dispersed and painted in the same manner as in Example 1,
It was left at room temperature for 24 hours to obtain a dry coating film of 30 μm.
This product was frozen at -21°C for 5 hours and the icing strength was measured. Comparative examples include one using a composition prepared in the same manner as in Example 1 except that lithium citrate was not used (Comparative Example 4-1), and one using a composition prepared by pressing Teflon resin to a thickness of 2 mm (Comparative Example 4-1). Example 4-
Regarding 2), the icing strength was also measured under the same conditions. The results of these tests are shown below.

[Table] Example 5 100 parts of polycondensation organopolysiloxane resin (trade name: Toray Silicone SH-237, non-volatile content 40%, number average molecular weight approximately 17000), lithium oxalate
2.5 parts and 40 parts of titanium dioxide were dispersed and coated in the same manner as in Example 1, dried at 50°C for 5 hours,
A coating film of 15 μm was obtained. This product was frozen at -26°C for 22 hours and the icing strength was measured. Comparative examples include one using a composition prepared in the same manner as in Example 1 except that lithium oxalate was not used (Comparative Example 5-1), and one using a composition prepared by pressing Teflon resin to a thickness of 2 mm (Comparative Example 5-1). Example 5-
Regarding 2), the icing strength was also measured under the same conditions. The results of these tests are shown below.

[Table] Example 6 100 parts of condensation type organopolysiloxane aqueous coating material (trade name: Toray Silicone, SE-1980 non-volatile content 45%) and 1.2 parts of sodium chloride were dispersed and coated in the same manner as in Example 1. After leaving it at room temperature for 48 hours, it was dried at 50°C for 3 hours to obtain a coating film of 30 μm. This product was frozen at -20°C for 5 hours and the icing power was measured. Comparative examples include one using a composition prepared in the same manner as in Example 1 except that sodium chloride was not used (Comparative Example 6-1), and one using a composition prepared by pressing Teflon resin to a thickness of 2 mm (Comparative Example 6-1). 6-2)
The icing strength was also measured under the same conditions. The results of these tests are shown below.

[Table] Example 7 Addition polymerization type organopolysiloxane resin (Product name: Toray Silicone SH9551RTV, non-volatile content 100
%) and 10 parts of lithium carbonate were dispersed in the same manner as in Example 1, and a platinum-based catalyst (Example 1
The composition obtained by adding and stirring 10 parts of the same material as above was molded onto a substrate for adhesion testing to form a uniform flat surface with a thickness of 2 mm. This product was dried at room temperature for 48 hours and then frozen at -29°C for 18 hours, and the icing power was measured. In addition, as comparative examples, one was molded using a composition prepared in the same manner as in Example 1 except that lithium carbonate was not used (Comparative Example 7-1), and one was molded using Teflon resin to a thickness of 2 mm (Comparative Example 7-1). Comparative example 7
-2) The icing strength was also measured under the same conditions. The results of these tests are shown below.

【table】 [Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of an apparatus for testing the icing properties of the composition for anti-icing materials of the present invention. 1... Copper plate, 2... Styrofoam container, 3... Stainless steel coated plate, 4... Paint film, 5... Adhesive terminal, 6... Thin film of water, 7... Adhesion tester, 8... Support stand, 9... Measuring tube, 10... Coil Spring, 11...Rubber gasket.

Claims (1)

[Claims] 1 (A) The following 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 n+m
is less than 4) Organopolysiloxane resin 70~
99.8% by weight and (B) the following formula Ma ) A composition for anti-icing material comprising 0.2 to 30% by weight of an alkali metal compound represented by: 2. The composition for anti-icing material according to claim 1, wherein the alkali metal compound is a lithium compound.