JPH0450046B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is said to be useful as an antifoaming agent for paints, particularly for defoaming foaming in organic solvent-based solutions such as paints. This article relates to antifoaming agents for paints. (Prior technology) Silicone antifoaming agents exhibit excellent antifoaming effects when added in trace amounts of 10 to 200 ppm.They have excellent heat resistance and chemical resistance, and are chemically inert, so they foam even under adverse conditions. It is stable and does not react with substances.
It is safe to add to the food manufacturing process as it is non-toxic under the Food Sanitation Law, and is safe to use in wastewater treatment. It is widely used in industrial processes, including oil compounds made by mixing silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylvinylpolysiloxane with finely powdered silica; An emulsion-type product is used, which is obtained by dispersing it in water together with a surfactant. However, although these silicone-based antifoaming agents exhibit excellent antifoaming effects against aqueous foaming, they have lower surface tension than aqueous foaming agents, and are less effective against foaming from organic solvents in which silicone has greater solubility. This has the disadvantage that the foaming effect becomes inferior. Therefore, as an antifoaming agent for organic solvent systems, a method has been proposed in which a composition consisting of dimethylpolysiloxane and siloxane resin is used to suppress foaming when processing petroleum residues into oil coke. (Refer to Japanese Patent Application Laid-Open No. 53-98306) However, this antifoaming effect is not satisfactory. A method using perfluoroalkyl group-containing siloxane, which is poorly soluble in organic solvents, has also been proposed (Tokuko Sho
(Refer to Publication No. 35-12564) However, it has problems with solubility and dispersibility in solvents, and when added to paints, it causes repellency such as pinholes and hard eyes, so this paint does not have good properties. There is a disadvantage that a coating film cannot be obtained. (Structure of the Invention) The present invention relates to an antifoaming agent for paints that solves the above-mentioned disadvantages.

[Formula] (where R ^f is a perfluoroalkyl group having 1 to 14 carbon atoms,
R ¹ is a divalent hydrocarbon group having 1 to 8 carbon atoms, R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, a
is 1≦a≦3, b is 0≦b≦2, and a+b is 1≦a
20 to 70 mol% of organosiloxane units represented by +b≦3, a positive integer), 2) General formula (R ⁴ is a hydrogen atom, a lower alkyl group or an acyl group, R ⁵ is a divalent hydrocarbon group having 2 to 6 carbon atoms,
R ⁵ is a divalent hydrocarbon group having 1 to 8 carbon atoms, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, l
is an integer greater than or equal to 1, m and n are each 0 or 1,
c is 1≦c≦3, d is 0≦d≦2, and c+d is 1
0.2 to 10 mol% of organosiloxane units (a positive integer that satisfies ≦c+d≦3), 3) General formula

[Formula] (where R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and e is 1, 2 or 3) 79.8 to 20 organosiloxane units
The main ingredient is an organopolysiloxane consisting of mol %. That is, as a result of various studies on the development of antifoaming agents for paints that exhibit excellent antifoaming effects against foaming caused by organic solvents, the present inventors have developed a conventionally used general formula.

An organopolysiloxane consisting of an organosiloxane unit represented by the formula, where R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and a is 1.2 or 3, is used as a perfluoroalkyl group-containing organosiloxane. When this substance contains units, the surface tension and solubility in organic solvents decrease, and therefore it shows an excellent effect in suppressing foaming in organic solvent systems, but when used as an additive for paints, it is Since this gives the paint a repelling phenomenon that causes pinholes, hard eyes, etc., adding an organosiloxane unit containing a polyether group to the paint creates a well-balanced surface tension and solubility in organic solvents. In addition to exhibiting excellent physical properties as an antifoaming agent for paints,
We discovered that it does not cause repellency in paints when used as a paint additive, and we have developed the types and amounts of perfluoroalkyl group-containing organosiloxane units and polyether group-containing organosiloxane units to be used. The present invention was completed by conducting research on the following. Below, the organopolysiloxane used in the antifoaming agent for paints of the present invention will be explained in detail. The organopolysiloxane used in the antifoaming agent for paints of the present invention is composed of the three types of organosiloxane units described above. The perfluoroalkyl group-containing organosiloxane unit constituting this organopolysiloxane has the general formula R ^f is a linear or branched perfluorocarbon group having 1 to 14 carbon atoms, such as perfluoropropyl group, perfluorobutyl group, perfluorohexyl group, perfluorooctyl group, perfluorodecyl group, etc. Fluoroalkyl group, R ¹ is methylene group,
Divalent hydrocarbon group having 1 to 8 carbon atoms, exemplified by ethylene group, propylene group, phenylene group, etc., R ²
is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a cycloalkyl group such as a cyclohexyl group, an alkenyl group such as a vinyl group or an allyl group, an aryl group such as a phenyl group or a tolyl group,
1 to 8 carbon atoms selected from aralkyl groups such as phenylethyl groups, or chloromethyl groups and cyanoethyl groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc. unsubstituted or substituted same or different monovalent hydrocarbon groups, a is 1≦a≦3, b
It is assumed that 0≦b≦2 and a+b is a positive integer of 1≦a+b≦3. This organosiloxane unit is For example, if the content is less than 20 mol% of this perfluoroalkyl group-containing organosiloxane unit in the organopolysiloxane, the surface tension of the organopolysiloxane will not be sufficiently lowered, and it will not dissolve in the organic solvent. If the content exceeds 70 mol%, the dispersibility in organic solvents and the ability to expand into foam become poor, resulting in insufficient antifoaming effects, especially foam-breaking properties and quick-acting properties. Therefore, it is necessary to set it in the range of 20 to 70 mol%. In addition, the polyether group-containing organosiloxane unit constituting this organopolysiloxane has the general formula , R ³ is a hydrogen atom, a methyl group, an ethyl group,
Lower alkyl groups such as propyl and butyl groups, or acyl groups such as acetyl and propionyl groups,
R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, exemplified by ethylene, propylene, isobutylene, etc., and R ⁵ is a carbon number 1, exemplified by methylene, ethylene, propylene, phenylene, etc. ~8
is a divalent hydrocarbon group, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms similar to R ² described above,
l is an integer greater than or equal to 1, m and n are each 0 or 1, c is a positive integer such that 1≦c≦3, d is 0≦d≦2, and c+d is 1≦c+d≦3. . This polyether group-containing organosiloxane unit is If the content is less than 0.2 mol% of this polyether group-containing organosiloxane unit in the organopolysiloxane, the anti-repellency effect of the paint will be insufficient when this silicone antifoaming agent is added to the paint system. If it is 10 mol% or more, the solubility of this organopolysiloxane in organic solvents will become too large and the antifoaming effect in organic solvent systems will decrease, so 0.2 to 10 mol%
It needs to be within the range of Next, the organosiloxane units that make up this organopolysiloxane have the general formula , and this R ⁷ is the same or different unsubstituted or substituted one having 1 to 8 carbon atoms as the above-mentioned R ²
The valence hydrocarbon group, e, is intended to be 1, 2 or 3. Examples of this include methylsiloxane group, phenylsiloxane group, vinylsiloxane group, trimethylsiloxane group, dimethylsiloxane group, methylphenylsiloxane group, dimethylphenylsiloxane group, dimethylvinylsiloxane group, methylvinylsiloxane group, etc. However, since the content of this organosiloxane unit in the organopolysiloxane is the remaining amount of the total amount of the two organosiloxane units mentioned above, it is 79.8 to 20.
It may be expressed as mol%. The organopolysiloxane used as the antifoaming agent for paints of the present invention contains three types of organosiloxane units represented by the above formulas (1), (2), and (3) within the above content range. However, this organopolysiloxane is, for example, an organosiloxane represented by the formula [(R ^f R ¹ ) R ² SiO] _p (where R ^f , R ¹ , and R ² are the same as above) and a formula (HR ⁷ SiO). _q and the formula (R ⁷ ₂ SiO) _r (where p, q, r are numbers from 3 to 5) are mixed in a predetermined ratio, an equilibration reaction is carried out in the presence of an acid, and then in this reaction product ≡SiH contained in
In the presence of a platinum catalyst, a polyether represented by the formula CH ₂ = CHCH ₂ (-OR ⁴ ) _l --O-R ³ ...(7) (where R ³ and R ⁴ are as described above) It can be obtained by the addition reaction described below, and the following are exemplified. The antifoaming agent for paints of the present invention containing the organopolysiloxane thus obtained as a main ingredient exhibits an excellent foam suppression effect against foaming caused by organic solvents, and
In particular, even when added to oil-based paint systems such as polyarylate-based and polyurethane-based paints, it does not cause repellency to the paint. This product may be added to an organic solvent system as it is, or may be added to a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone or 1,1,2-trifluoro-1,2,2
- It may be used after being dissolved in a halogen-containing organic solvent such as trichloroethane. Note that it is optional to add an antioxidant and a filler such as fumed silica to this organopolysiloxane depending on its use. Next, synthesis examples and examples of the organopolysiloxane used as the antifoaming agent for paints of the present invention will be given. Synthesis example 1 Hexamethyldisiloxane 17.4g, 1,3,5
-Tristrifluoropropyl-1,3,5-trimethylcyclotrisiloxane 671.4g, octamethylcyclotetrasiloxane 1246.5g and 1,3,5,7-tetramethylcyclotetrasiloxane 64.7g were mixed, and concentrated sulfuric acid After adding 20 g and reacting at room temperature for 8 hours, 40 g of water was added and stirred at room temperature for 4 hours, and then 40 g of sodium hydrogen carbonate was added to neutralize the acid. 1,900 g of organopolysiloxane (hereinafter abbreviated as siloxane A-1) represented by was obtained. Next, apply the formula to 1000g of this siloxane A-1. 970g of polyether and 1000g of toluene shown in
and 0.2 g of isopropyl alcohol solution of chloroplatinic acid (platinum concentration 2% by weight) were added, and after reacting for 8 hours at reflux temperature (115-118°C), 10 mmHg
When heated to 120℃ under reduced pressure, the formula 1.830 g of organopolysiloxane (hereinafter abbreviated as siloxane B-1) represented by the formula was obtained. Synthesis example 2 Hexamethyldisiloxane 8.4g, 1,3,5
-trisnonafluorohexyl-1,3,5-trimethylcyclotrisiloxane 1578.0g, octamethylcyclotetrasiloxane 382.6g and 1,
When 31.0 g of 3,5,7-tetramethylcyclotetrasiloxane was mixed and treated in the same manner as in Synthesis Example 1, the formula 1950 g of organopolysiloxane (hereinafter abbreviated as siloxane A-2) represented by the formula was obtained. Next, apply the formula to 21000g of this siloxane A- 438.3g of polyether and 1000g of toluene
g and 2.0 g of isopropyl alcohol solution of chloroplatinic acid (platinum concentration 2% by weight) were added and treated in the same manner as in Synthesis Example 1. 1,338 g of organopolysiloxane (hereinafter abbreviated as siloxane B-2) represented by the following formula was obtained. Synthesis example 3 Hexamethyldisiloxane 11.8g, 1,3,5
-tristrifluoropropyl-1,3,5-trimethylcyclotrisiloxane 1587.8g, octamethylcyclotetrasiloxane 315.8g and 1,
When 43.7 g of 3,5,7-tetramethylcyclotetrasiloxane was mixed and treated in the same manner as in Synthesis Example 1, the formula 1950 g of organopolysiloxane (hereinafter abbreviated as siloxane A-3) represented by the formula was obtained. Next, 31000 g of this siloxane A was given the formula CH ₂ =
163.6 g of polyether represented by CHCH ₂ -O(CH ₂ CH ₂ O) ₁₀ -H, 1000 g of toluene, and 2.0 g of an isopropyl alcohol solution of chloroplatinic acid (platinum concentration 2% by weight) were added, and the same as in Synthesis Example 1 was added. When processed, the formula 1082 g of organopolysiloxane (hereinafter abbreviated as siloxane B-3) represented by the formula was obtained. Synthesis example 4 Hexamethyldisiloxane 7.1g, 1,3,5
-tristrifluoropropyl-1,3,5-trimethylcyclotrisiloxane 1357.6g, octamethylcyclotetrasiloxane 630.1g and 1,
When 5.2 g of 3,5,7-tetramethylcyclotetrasiloxane was mixed and treated in the same manner as in Synthesis Example 1, the formula 1950 g of organopolysiloxane (hereinafter abbreviated as siloxane A-4) represented by the formula was obtained. Next, apply the formula to 41000g of this siloxane A- 252.4g of polyether and 1000g of toluene
g and 2.0 g of isopropyl alcohol solution of chloroplatinic acid (platinum concentration 2% by weight) were added and treated in the same manner as in Synthesis Example 1, resulting in the formula 1164.7 g of organopolysiloxane (hereinafter abbreviated as siloxane B-4) represented by the formula was obtained. Synthesis example 5 Hexamethyldisiloxane 5.5g, 1,3,5
-tris heptadecafluorodecyl-1,3,5
-1709.3 g of trimethylcyclotrisiloxane, 244.6 g of octamethylcyclotetrasiloxane and 40.6 g of 1,3,5,7-tetramethylcyclotetrasiloxane were mixed and treated in the same manner as in Synthesis Example 1. 1950 g of organopolysiloxane (hereinafter abbreviated as siloxane A-5) represented by the formula was obtained. Next, apply the formula to 51000g of this siloxane A- 567.5g of polyether and 1000g of toluene shown in
g and 2.0 g of isopropyl alcohol solution of chloroplatinic acid (platinum concentration 2% by weight) were added and treated in the same manner as in Synthesis Example 1, resulting in the formula 1457.8 g of organopolysiloxane (hereinafter abbreviated as siloxane B-5) represented by the formula was obtained. Synthesis example 6 Hexamethyldisiloxane 12.9g, 1,3,5
-tristrifluoropropyl-1,3,5-trimethylcyclotrisiloxane 1221.9g, octamethylcyclotetrasiloxane 574.5g and 1,
When 190.7 g of 3,5,7-tetramethylcyclotetrasiloxane was mixed and treated in the same manner as in Synthesis Example 1, the formula 1950 g of organopolysiloxane (hereinafter abbreviated as siloxane A-6) represented by the formula was obtained. Next, apply the formula to 1000g of this siloxane A-6. 2856g of polyether and 2000g of toluene shown in
When 2.0 g of isopropyl alcohol solution (platinum concentration 2% by weight) of chloroplatinic acid and chloroplatinic acid were added and treated in the same manner as in Synthesis Example 1, the formula 3586.0 g of organopolysiloxane (hereinafter abbreviated as siloxane B-6) represented by the formula was obtained. Synthesis example 7 Hexamethyldisiloxane 3.5g, 1,3,5
- Tristrifluoropropyl-1,3,5-trimethylcyclotrisiloxane 680.6g and octamethylcyclotetrasiloxane 315.9g were mixed, 10g of concentrated sulfuric acid was added thereto, the mixture was reacted at room temperature for 8 hours, and then 20g of water was mixed. was added and stirred at room temperature for 4 hours, and then 20 g of sodium hydrogen carbonate was added to neutralize the acid. 950 g of organopolysiloxane (hereinafter abbreviated as siloxane B-7) represented by was obtained. Examples 1 to 5, Comparative Examples 1 to 2 100 g of light oil and the siloxanes B-1 to B- obtained in Synthesis Examples 1 to 7 described above were placed in a measuring cylinder of 1.
70.01g and put these into a glass foaming tube and aerated at a speed of 1/min.1 minute, 3 minutes, 5 minutes.
When the amount of foaming was measured after 10 minutes, 10 minutes, 15 minutes, and 20 minutes, the results shown in Table 1 were obtained, and Siloxane B-1 to B-5 and B-7 had excellent antifoaming properties However, siloxane B-6 scaled over in 56 seconds. Next, 50% toluene solution of acrylic resin 100%
Siloxane B- obtained in Synthesis Examples 1 to 7 described above in g.
After adding 70.2 g of 1 to B-7 and stirring well, this was used to screen print on vinyl coated paper, and after drying, the number of repellents on a 5 cm square area on this printed surface was measured. Table 1 shows the results. The results as listed above were obtained, and siloxanes B-1 to B-
6 all showed excellent repellency prevention effects with the number of repellents being 0 or less than 3, but siloxane B-7
Poor results were shown for 150 to 200 pieces.

【table】

【table】

Claims (1)

[Claims] 1 1 General formula [Formula] (where R ^f is a perfluoroalkyl group having 1 to 14 carbon atoms, R ¹ is a divalent hydrocarbon group having 1 to 8 carbon atoms,
^R2 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, a is a positive integer in which 1≦a≦3, b is 0≦b≦2, and a+b is 1≦a+b≦3) 20 to 70 mol% of organosiloxane units, 2 General formula (R ³ is a hydrogen atom, a lower alkyl group or an acyl group, R ⁴ is a divalent hydrocarbon group having 2 to 6 carbon atoms, R ⁵ is a divalent hydrocarbon group having 1 to 8 carbon atoms,
R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, l is an integer of 1 or more, m and n are each 0 or 1, c is 1≦c≦3, and d is 0≦d≦
2, and c+d is a positive integer such that 1≦c+d≦3)
0.2-10 mol% 3 Organosiloxane unit represented by the general formula [Formula] (where R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and e is 1, 2 or 3) 79.8- An antifoaming agent for paints, characterized in that the main ingredient is an organopolysiloxane consisting of 20 mol%.