JPS6271506A - Defoaming agent for organic solvent - Google Patents

Abstract

PURPOSE:To obtain the titled defoaming agent capable of controlling frothing in an org. solvent wherein a hydrocarbon and a fluorine surfactant are dissolved by using 20-80mol% organopolysiloxane component having a fluoroalkyl group. CONSTITUTION:Organopolysiloxane consisting of 20-80mol% organosiloxane unit contg. a perfluoroalkyl group shown by formula I and 20-80mol% organosiloxane unit shown by formula II is used as the main agent. A defoaming agent contg. the organopolysiloxane as the main agent exhibits an excellent effect in controlling frothing in an org. solvent or especially in an org. solvent wherein a hydrocarbon or a fluorine surfactant are dissolved. The defoaming agent can be directly added to the desired org. solvents, or 20-50wt% of the agent is dissolved in a ketonic or a halogen-contg. org. solvent and used.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is an antifoaming agent for organic solvents, particularly an antifoaming agent that has excellent foam suppression properties against bubbles in an organic solvent solution in which a hydrocarbon or fluorine surfactant is dissolved. This invention relates to an effective antifoaming agent for organic solvents containing a perfluoroalkyl group-containing organosiloxane as an active ingredient.

(Prior Art) Silicone antifoaming agents have various superior properties compared to other antifoaming agents, so they are widely used in industrial methods that involve foaming, including dimethylpolysiloxane, Oil compounds are used by mixing silicone oils such as methylphenylpolysiloxane and methylvinylpolysiloxane with finely powdered silica, and emulsion-type products are used in which these oil compounds are dispersed in water with surfactants. .

However, although these silicone-based antifoaming agents exhibit excellent antifoaming effects for aqueous-based foaming, they have lower surface tension than aqueous-based antifoaming agents and cannot be used as organic solvent-based antifoaming agents in which silicone has a high solubility. has the disadvantage that its effect is extremely weak. Therefore, it has been proposed to use dimethylpolysiloxane, which has a particularly high viscosity, as an organic solvent-based antifoaming agent (see Japanese Patent Publication No. 12564/1983), but this does not necessarily show an excellent antifoaming effect. A method has also been proposed in which a composition consisting of dimethylpolysiloxane and siloxane resin is used to suppress foaming when processing petroleum residues into oil coke (see JP-A-53-98306). This also has an unsatisfactory defoaming effect.

Note that the above-mentioned Japanese Patent Publication No. 35-12564 also describes the use of perfluoroalkyl group-containing organosiloxane as an antifoaming agent, but this product contains 90 mol% or more of perfluoroalkyl groups. Therefore, the dispersibility is difficult and the range of its use is limited.

(Structure of the Invention) The present invention relates to an antifoaming agent that solves such disadvantages and exhibits an excellent antifoaming effect against foaming caused by organic solvents. A is a monovalent group represented by the formula RfR''- (Rf is a perfluoroalkyl group having 1 to 14 carbon atoms, R2 is a divalent hydrocarbon group having 1 to 8 carbon atoms), and R1 is a hydrogen atom or a carbon number 1 to 8 unsubstituted or substituted monovalent hydrocarbon groups, a is 1
20 to 80 mol% of organosiloxane units represented by ≦a≦3, b is a positive number where O≦b≦2 and 1≦a+b≦3, 2) General formula Rc S x O earthwork (here R3 is The main ingredient is an organopolysiloxane consisting of a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and 20 to 80 mol% of organosiloxane units represented by C is 1.2 or 3). It is characterized by this.

That is, the present inventors have conducted various studies on silicone-based antifoaming agents that exhibit excellent antifoaming effects particularly against foaming caused by organic solvents. Since siloxane has a low surface tension and low solubility in organic solvents, it exhibits an excellent effect in suppressing foaming in organic solvents. Since there are difficulties in diluting with a solvent, this can be solved by using the siloxane unit shown in the general formula (1) above and the general formula.
R35iO... (2) If the organopolysiloxane contains both of the siloxane units shown in C earthwork, the surface tension and solubility in organic solvents will be balanced and it will have excellent physical properties as an organic solvent-based antifoaming agent. We have discovered that a silicone antifoaming agent with a fluorine-containing antifoaming agent can be obtained, and that this antifoaming agent exhibits an excellent foaming suppressing effect, especially in organic solvent systems in which hydrocarbon or fluorine surfactants are dissolved. The present invention was completed by conducting research on the molar ratio of the siloxane units represented by formulas (1) and (2), the method for producing this organopolysiloxane, and the method for using it as an antifoaming agent. .

The organopolysiloxane as the main ingredient constituting the antifoaming agent for organic solvents of the present invention consists of perfluoroalkyl group-containing organosiloxane units represented by the general formula (1) and organosiloxane units represented by the general formula (2). It is necessary to contain both.

This perfluoroalkyl group-containing organosiloxane unit is represented by the above-mentioned general formula (1), where A is a monovalent group represented by RfR''- and R
f is a perfluorobutyl group, a perfluorohexyl group,
A linear or branched perfluoroalkyl group having 1 to 14 carbon atoms, exemplified by perfluorooctyl group, perfluorobutyl group, etc., R2 is a methylene group, an ethylene group,
1 carbon number exemplified by propylene group, phenylene group, etc.
~8 divalent hydrocarbon group, R1 is a hydrogen atom or 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, a vinyl group, an allyl group, etc. alkenyl groups, phenyl groups, aryl groups such as tolyl groups, aralkyl groups such as 2-phenylethyl groups, and furthermore, some or all of the hydrogen atoms bonded to the carbon atoms of these groups are replaced with halogen atoms, cyano groups, etc. An unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms selected from a substituted chloromethyl group, trifluoropropyl group, cyanoethyl group, etc., a and b are each 1≦a≦3.0≦b≦2 1≦a and b≦3, and the following are examples of these.

CH.

Note that this perfluoroalkyl group-containing organosiloxane is, for example, RI CHz GHz (R') n SiC (
13-n (R,, R1 is the same as above, n is 0.1.2)
Will the organochlorosilane shown in be hydrolyzed?

RfCH,CH,(R')SiCn, (Rf, R1 are the same as above) is hydrolyzed in the presence of an alkali to obtain a formula% formula% body, which is then treated with a catalyst such as a strong acid or a strong alkali. It can be obtained by equilibration reaction in the presence of

In addition, R3 in the organosiloxane represented by the general formula (2) R35iOC-L≦- is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms similar to the above R'', and C is 1 .2 or 3,
It is a common organosiloxane exemplified by dimethylsiloxane, methylphenylsiloxane, methylvinylsiloxane, etc., but this organosiloxane has R
” A cyclic body obtained by hydrolysis of an organochlorosilane represented by SiCQ, -n (R3, n are the same as above) or a luganochlorosilane represented by R35iCQ2 is heated in the presence of a catalyst such as a strong acid or a strong alkali. It can be obtained by an equilibration reaction.

The organopolysiloxane containing both the perfluoroalkyl group-containing siloxane unit represented by the general formula (1) and the siloxane unit represented by the general formula (2) is as described above (RfCH2CHx (R') S x O)
[RffSi○]2 obtained by hydrolysis of the cyclic body represented by a and R35iCQ2
2
It can be obtained by equilibration reaction with a cyclic body represented by n in the presence of an end-capping group, but it can also be obtained by cohydrolysis of organosilane as described below.

2A, R15iX+p(R3SiX, )+q(AR
1SiX2)-m m
2+ r (A, SiX,) + H2O -8i R1A 3- m m (A, R1, R3 are the same as above, or a halogen atom, p
, q, and r are positive numbers, and m is 0.1.2 or 3) However, if the perfluoroalkyl group-containing organosiloxane unit contained in the resin is less than 20 mol%, the surface of this organopolysiloxane The tension is not lowered enough, and the foam suppression effect against foaming in systems containing organic solvents and fluorosurfactants with lower surface tensions is not as great as expected, and the solubility in organic solvents is too high. Therefore, its foam suppressing effect becomes insufficient, and when it exceeds 80 mol%, its solubility in organic solvents decreases, making it difficult to use the type of diluent organic solvent added when using it as an antifoaming agent. 20 to 8
Although a range of 0 mol% is required, the preferred range is 30 to 70 mol%.

Note that this antifoaming agent for organic solvents containing organopolysiloxane as a main ingredient may be added as is to the target organic solvent system, but when using this as an antifoaming agent, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketone solvents such as 1,1,2-trifluoro-1゜1.2-
Add halogen-containing organic solvent such as trichloroethane, hexafluoroxylene, hexafluoropropylene oligomer, 1,1.3-dolichloroethane, 1,1,2.2-tetrachloroethylene to a concentration of about 20 to 50% by weight. It is preferable to use it by dissolving it in

The composition of the present invention, which has the above-mentioned organopolysiloxane as a main ingredient, exhibits excellent foaming suppressing effects in organic solvents, especially organic solvents in which hydrocarbon or fluorocarbon surfactants are dissolved. Specific examples of organic solvents that require foam include oil-based paints such as polyacrylate, polyurethane, and epoxy paints, wetting agents in which hydrocarbon or fluorine surfactants are dissolved, and fire extinguishing agents. . In addition, this product includes water and oil repellents in which perfluoroacrylate polymers and copolymers are dissolved, antifouling agents, SR agents, and softeners containing amphoteric activators. It also shows the effect of effectively suppressing foaming caused by antistatic agents and the like, or foaming when recovering perchloroethyl etc. from dry cleaning liquids containing these compounds as fiber treatment agents.

Next, synthesis examples and examples of organopolysiloxane, which is the main ingredient of the antifoaming agent of the present invention, will be shown.

Synthesis Example 1 1.3.5-trimethyl-1,3,5-tris(3,3
Predetermined amounts of 3-trifluoropropyl) cyclotrisiloxane, octamethylcyclotetrasiloxane, and hexamethyldisiloxane as an end-blocking agent are charged into a Mitsuro flask, and 0% of the total amount of siloxane is added.
．． After adding 0.5% by weight of trifluoromethanesulfonic acid as a catalyst and reacting at room temperature for 4 hours, 20% of the catalyst was added.
Neutralize by adding twice the amount of sodium hydrogen carbonate, and after passing through the furnace,
When unreacted monomers were stripped for 2 hours at 140°C under a reduced pressure of mmHg, the following organopolysiloxanes were obtained depending on the amount of each added.

Sample-1 (R content 50 mol%) Sample-2 (R content 75 mol%) Comparative example-1 (R content 17 mol%) Comparative example-2 (Rf content 100 mol%) 320 g of 50% aqueous solution of sodium hydroxide , 296 g of octamethylcyclotetrasiloxane and 1 methanol
Pour 40g into a Mitsuro flask, heat and stir at 95°C for 2 hours to make the contents uniform, and add 1.00 g of toluene.
After removing water and methanol azeotropically, 722 g of nonafluorohexylmethyldichlorosilane was added.
was added dropwise, the white precipitate formed was filtered, and the solvent was removed with a strip to obtain a colorless and transparent oily liquid, which contained 33.3 mol% of nonafluorohexylmethylsiloxane units and dimethylsiloxane. unit 6
Perfluoroalkyl group-containing organopolysiloxane with an average degree of polymerization of about 60 and consisting of 6.7 mol% (Sample-3)
)Met.

Synthesis Example 3 The same process as in Synthesis Example 2 was performed except that 148 g of octamethylcyclotetrasiloxane was used instead of 296 g of octamethylcyclotetrasiloxane in Synthesis Example 2 above, and a colorless and transparent oily liquid was obtained. , this one has 5 nonafluorohexylmethylsiloxane units.
The perfluoroalkyl-containing organopolysiloxane (Sample-4) had an average degree of polymerization of about 60 and consisted of 0 mol% and 50 mol% of dimethylsiloxane units.

Synthesis Example 4 The same procedure as in Synthesis Example 2 was carried out except that 1,122 g of heptadecafluorodecylmethyldichlorosilane was used instead of 722 g of nonafluorohexylmethyldichlorosilane in Synthesis Example 2 above, and a colorless and transparent oily liquid was obtained. This product is a perfluoroalkyl-containing organopolysiloxane (Sample-5) having an average degree of polymerization of about 60 and consisting of 33 mol% of butadecafluorodecylmethylsiloxane units and 67 mol% of dimethylsiloxane units.
Met.

Synthesis Example 5 Sample-3 obtained in Synthesis Example 2, octamethylcyclotetrasiloxane, and a predetermined amount of hexamethyldisiloxane as an end-blocking agent were charged into a Mitsuro flask, and 0.05% by weight was added to the total amount of siloxane. % of trifluoromethanesulfonic acid as a catalyst and treated in the same manner as in Synthesis Example 1 to synthesize siloxane, the following organopolysiloxanes were obtained depending on the amount of each added.

Sample-6 (Rf content 22 mol%) Sample-7 (Rf content 32 mol%) Comparative example-3 (Rf content 12 mol%) Synthesis example 6 Sample-5 obtained in synthesis example 4 and octamethylcyclotetrasiloxane Predetermined amounts of hexamethyldisiloxane and hexamethyldisiloxane as an end-capping agent were charged into a Mitsuro flask and treated in the same manner as in Synthesis Example 5, whereby the organopolysiloxanes shown below were obtained depending on the amounts added.

Sample-8 (Rf content 22 mol%) Sample-9 (Rf content 32 mol%) Comparative example-4 (Rf content 12 mol%) Example 1 Calcium dodecylbenzenesulfonate 2% by weight, seranol 3% by weight, water 1% by weight % and toluene 94% by weight. was weighed into a 500 mfi measuring cylinder, and sample 1 obtained in Synthesis Examples 1 to 6 described above was added to it.
~9. 30% solution of 1.1.2-trifluoro-1,1,2-trichloroethane of antifoaming agent of Comparative Examples 1 to 4 0.0
Add 1g (60ppm as active ingredient) and add 1127 ml of air through a diffuser stone at room temperature.
When the amount of foaming was examined over time when the foaming amount was continuously introduced at a rate of 1.5 min, the results shown in Table 1 were obtained.

Table 1 Example 2 Methyl chloroform of perfluorooctylethyl acrylate/2-ethylhexyl acrylate copolymer 2
0% by weight solution of Scotchgard FC-905 (trade name manufactured by Sumitomo 3M ■) 1゜1.2-trichloroethane 2
Weigh out 70g of the 0% solution into a 200mQ measuring cylinder with a stopper, add the predetermined amounts of the antifoaming agents of Samples 1 to 9 obtained in Synthesis Examples 1 to 6 and Comparative Examples 1 to 4, and then 30
The mixture was shaken by hand 30 times within seconds, and the amount of foaming was measured immediately after shaking and 60 seconds later, and the results shown in Table 2 were obtained.

Table 2 - F Continuing Amendment November 15, 1985 Director General of the Patent Office Michibu Uga 1. Indication of the matter 1985 Patent Application No. 213284 2, Name of Issue 1!11 A I Organic Solvent River Foaming Agent 3, Supplement 1]: Person who does 1<Relationship with Patent Applicant Name (206) Shin-Etsu Chemical Co., Ltd. 4, Agent Address 4-9 Nihonbashi Honmachi, Chuo-ku, Tokyo 103 street address"
6. Subject of amendment: ``Column for detailed explanation of the invention'' 7. Contents of amendment 5. sil) "Industrial construction method" on page 2, line 14 of the specification is changed to "industrial process"
and correct it.

2) "Defoaming agent" in line 4 of page 3 of the specification is corrected to "foaming" and "high viscosity" in line 6 of the same page is corrected to "poorly soluble."

3) Change the chemical formula in lines 3 to 4 on page 9 of specification 3 to CHC as shown below.
H3 CH3J o "R content" on page 15, lines 4, 6, and 8 of the specification is r
Correct R as "content".

5) "Butadecafluoro" on page 17, line 16 of the specification is replaced with "
Heptadecafluoro”.

8) "20% solution" on page 23, line 6 of the specification is corrected to "20% solution by weight (4% active ingredient)".

that's all

Claims (1)

[Claims] 1, 1) General formula A_aR^1_bSiO[_4_-_(
_a_+_b_)]_/_2 [Here, A is the formula R_fR^
The monovalent group R^1 represented by 2- (R_f is a perfluoroalkyl group having 1 to 14 carbon atoms, R^2 is a divalent hydrocarbon group having 1 to 8 carbon atoms) is a hydrogen atom or a hydrogen atom or a group having 1 to 8 carbon atoms. 8 unsubstituted or substituted monovalent hydrocarbon groups, a is 1≦a≦3, b is 0
20 to 80 mol% of organosiloxane units represented by a positive number where ≦b≦2 and 1≦a+b≦3, 2) General formula R^3_cSiO(_4_-_c)_/_
2 (where R^3 hydrogen atom or unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, c is 1, 2, or 3), and 80 to 20 mol% of organosiloxane units. An antifoaming agent for organic solvents characterized by containing organopolysiloxane as a main ingredient.