JPH0118762B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to antifoaming agents. More specifically, the present invention relates to an antifoaming agent that is excellent in suppressing foaming caused by organic solvents, particularly organic solvent solutions containing water and oil repellents. A large number of various antifoaming agents have been proposed in the past, such as (1) those containing polydimethylsiloxane, polyphenylmethylsiloxane, polypropylmethylsiloxane, etc. as main components, or those containing these as main components, such as hydrocarbon oils, polyether oils, etc. Silicone antifoaming agents such as oil compositions such as oil compositions or compounds with finely powdered silica etc. , see Publication No. 48-36084),
(2) Polyalkylene glycols such as polyethylene glycol and co-poly(ethylene glycol/propylene glycol) (see Japanese Patent Publication No. 1475-1983), (3) Polyvalent metal soaps (see Japanese Patent Publication No. 11328-1987), (4) Alkyl phosphate esters or alkyl phosphite esters (see Japanese Patent Publication No. 12177/1984). All of these are mainly aimed at defoaming aqueous solutions and emulsions, and some are also aimed at organic solvent solutions.
The effect is small. That is, although these antifoaming agents can eliminate foam caused by water/hydrocarbon surfactants, they cannot eliminate foam caused by organic solvents, which have a lower surface tension. In addition, ordinary fluorine-based surfactants with the structure shown below have the effect of eliminating organic solvent-based foam.
It cannot be said that it is particularly excellent. R _f -R R _f : Lipophobic group (or hydrophobic group) R: Lipophilic group (or hydrophilic group) In particular, water and oil repellents made of organic solvent solutions of polyfluorocarbon group-containing copolymers are used for dry cleaning. When an organic solvent is used, it foams violently when the organic solvent is recovered from it, and it is practically impossible to suppress foaming in such a system using a commonly used antifoaming agent. . The present inventors have conducted various studies in search of an antifoaming agent that has an excellent effect of suppressing foaming caused by organic solvents, especially organic solvent solutions containing water and oil repellents, and have found that a specific perfluoropolyether compound is extremely effective. I found that. Therefore, the present invention relates to _an antifoaming agent, _which has the general formula _: Fluorinated group or one end
is an R _f group, Y is a hydrogen atom or R _f with fluorine added at one end, and R _f is a general formula (CF ₂ O
)− _p (−C ₂ F ₄ O)− _q (−C ₃ F ₆ O) a group represented by _r ,
n, m, p, q and r are the number of bonds, r is 0
The perfluoropolyether compound represented by the following formula is used as an active ingredient. Such perfluoropolyether compounds are, for example, peroxy group-containing polyethers ( _CF2O ) _-s ( _-C2F4O ) _-t ( _-C3F6O ) as described in Japanese Patent Publication _{No. 49-45719} . ) − _u (−O) _v is irradiated with ultraviolet light to convert it into polyether (CF ₂ O) − _p (−C ₂ F ₄ O) − _q (−C ₃ F ₆ O ₎ It can be obtained by reacting with an alkylene glycol such as ethylene glycol or propylene glycol in the presence of a dehydrofluorination catalyst such as tetraethylamine. Examples of perfluoropolyether compounds obtained in this manner include the following. HO[-(CH ₂ CH ₂ O)- _o COR _f COO]- _n H FR _f [-(CH ₂ CH ₂ O)- _o COR _f COO]- _n H HO[-(CH ₂ CH ₂ O)- _o COR _f COO〕− _n R _f F FR _f [−(CH ₂ CH ₂ O) − _o COR _f COO〕− _n R _f F In addition, whether both terminal groups become fluorinated R _f groups or Alternatively, whether it becomes a hydroxyl group or a carboxyl group is determined by the reaction molar ratio of the polyether obtained by ultraviolet irradiation and alkylene glycol. It tends to form _f groups, and conversely, if there is less polyether, it tends to form hydroxy or carboxy end groups. Furthermore, in the perfluoropolyether compound represented by the above general formula, n is the number of bonds depending on the molecular weight of the polyalkylene glycol and is generally about 3 to 200, and m is the number of bonds between the polyalkylene glycol and the polyalkylene glycol reacting with it. This is the number of bonds determined by the molar ratio with ether. In addition, regarding the number of bonds p, q, r of polyether, p is 1 to 99,
In general, q can take a ratio of 1 to 70, r can take a ratio of 0 to 98, and when r is 0, p and q can each take a ratio of 1 to 99. When such a perfluoropolyether compound is used as an antifoaming agent, this compound can be added as is to the object to be antifoamed, but generally 1,1,2-trifluoro-1,2,2 -trichloroethane, hexafluoroxylene, 1,
It is used by dissolving it in a halogen-containing organic solvent such as 1,1-trichloroethane, trichlorethylene, perchlorethylene, chloroform, hexafluoropropylene oligomer (its fluorinated product) to a concentration of about 5 to 50%. . This compound can also be used in conjunction with other antifoam materials such as organosilicones, fluorosilicone, ethylene glycol, nonionic surfactants, and the like. The antifoaming agent according to the present invention is particularly excellent in suppressing foaming caused by organic solvents, particularly organic solvent solutions containing water and oil repellents. Water and oil repellents usually contain about 10 to 75% by weight of vinyl monomers having perfluoroalkyl groups and about 90 to 75% by weight of other vinyl monomers.
25% by weight of the copolymer with 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethylene, trichlorethylene, toluene, xylene,
Butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, 1,2,2-trifluoro-1,
It is prepared by dissolving it in 1,2-trichloroethane, fluorocarbons, etc. to a concentration of about 5 to 35% by weight.
Organic solvent solutions containing water and oil repellents include, for example, dry cleaning liquids containing water and oil repellents, and the foaming that occurs when perchlorethylene, etc. is recovered from these liquids is the main problem. This is effectively prevented by adding the antifoaming agent according to the invention. In addition, it is effective for defoaming polyacrylate-based or polyurethane-based paints, silicone-based varnishes, and the like. The antifoaming agent added is used in a proportion of about 0.001 to 30% by weight, preferably about 0.01 to 20% by weight, more preferably about 0.1 to 15% by weight, based on the solution of water and oil repellents, paints, varnishes, etc. It will be done. The antifoaming agent according to the present invention has an excellent effect of suppressing foaming caused by an organic solvent, especially an organic solvent solution containing a water and oil repellent, and moreover, it has almost the original effect of a water and oil repellent. It won't cause any damage. Next, the effects of the present invention will be explained with reference to Examples. Note that each reference example describes a method for producing a perfluoropolyether compound used as an active ingredient of an antifoaming agent. Reference example 1 300 ml of 1,1,2-trifluoro-
A 1,2,2-trichloroethane solvent was placed in the solvent, and a 150W ultraviolet lamp housed in a quartz sheath was immersed in the longitudinal center of the solvent. Under the future ultraviolet irradiation, perfluoroethylene was applied at a flow rate of 60% per hour.
Oxygen gas is also flowed at a flow rate of 20 per hour. Liquid temperature -10
After continuing the reaction at ℃ for 5 hours, the low-boiling fraction was distilled off from the reaction solution, and F ¹⁹ NMR revealed that a peroxy group-containing polyether (average molecular weight approximately 2000, per molecule) was found to have the following structure. On average, 40 g of 1 peroxide was obtained. (CF ₂ O) − _2.2 (−C ₂ F ₄ O) − _7.3 (−O) _0.5 A total of 200 g of the obtained peroxy group-containing polyether was placed in the glass reaction vessel and heated at a temperature between room temperature and 50°C. , irradiate with ultraviolet light for about 2 hours. 178 g of the product no longer has peroxide bonds, since it does not color the aqueous potassium iodide solution;
It is a polyether (average molecular weight approximately 1300) that is thought to have the following structure. (CF ₂ O) - _1.0 (-C ₂ F ₄ O) _2.3 130 g of the polyether thus obtained and 25 g of ethylene glycol were dissolved in 1,1,2-trifluoro-1,2,2-trichloroethane- In 500 ml of dioxane (1:1) mixed solvent, tetraethylamine is used as a dehydrofluorination catalyst and reacted at room temperature for 8 hours. The production of ester was confirmed in 139 g of the product from the absorption at 1780 cm ^-1 in the infrared absorption spectrum, and it is thought to have the following structure. X[-(-CH ₂ CH ₂ O)- _o COR _f COO]- _n Y [X: OH or R _f group with fluorine added at one end Y: H or fluorine added at one end R _f group R _f : (CF ₂ O) − _1.0 (−CF ₂ CF ₂ O) _2.3 Reference Example 2 In Reference Example 1, perfluoropropylene was used instead of perfluoroethylene at a flow rate of 60 per hour. 62g of peroxy group-containing polyether having an average molecular weight of about 3200 was obtained, which is thought to have the following structure. (CF ₂ O) − _3.5 (−C ₂ F ₄ O) − _7.2 (−C ₃ F ₆ O) − _10.9 (
-O) _1.0 A total of 320 g of the peroxy group-containing polyether thus obtained was used and irradiated with ultraviolet rays in the same manner as in Reference Example 1. A polyether (average molecular weight approximately 1800) that is thought to have the following structure is
252g was obtained. (−CF ₂ O) _1.0 (−C ₂ F ₄ O) − _2.0 (−C ₃ F ₆ O) _3.1 Using 180 g of the obtained polyether, Reference Example 1
The reaction with ethylene glycol was carried out in the same manner. As a result, a perfluoropolyether compound thought to have the following structure,
185g was obtained. X[-(-CH ₂ CH ₂ O)- _o COR _f COO]- _n Y [X: OH or R _f group with fluorine added at one end Y: H or fluorine added at one end R _f group R _f : (C ₃ F ₆ O) − _3.1 (−C ₂ F ₄ O) − _2.0 (−CF ₂ O) _1.0
] Example 1 A water and oil repellent made of a 1,1,1-trichloroethane solution of perfluorooctylethyl acrylate-cyclohexyl acrylate (weight ratio 50:50) copolymer was diluted with perchlorethylene to a concentration of 0.5%, 5% to the copolymer in this diluted solution.
A corresponding amount of the antifoam agent obtained in each reference example is added.
10 ml of this solution was placed in a stoppered test tube with an inner diameter of 15 mm and a capacity of 25 ml, and was vigorously shaken up and down 10 times, and the height of the bubbles was measured in 0.5 ml units immediately and 60 seconds later. Example 2 In Example 1, a perfluorooctylethyl acrylate-benzyl methacrylate (weight ratio 50:50) copolymer was used as the water and oil repellent copolymer. Examples 3 to 5 In Example 1, a commercially available water and oil repellent was used instead of the water and oil repellent made of a copolymer solution. (Example 3) Asahi Glass product AG-650 (Example 4) Kao soap product Wonder Guard (Example 5) Genbu product Social Finish The results of the foaming test for each of the above examples are shown in the table below. .

【table】

【table】

Claims (1)

_{[ Claims} ] 1 General _formula
R _f group, Y is a hydrogen atom or an R _f group with fluorine added at one end, and R _f has the general formula (CF ₂ O) − _p (− C ₂ F ₄ O) − _q (− C ₃ F ₆ O) a group represented by _r , where n, m, p, q and r are the number of bonds, and r may be O] as an active ingredient. Antifoaming agent. 2. The antifoaming agent according to claim 1, which is added to an organic solvent-based object to be defoamed. 3. The antifoaming agent according to claim 2, which is added to an organic solvent-based object to be defoamed containing a water and oil repellent.