JPS6116484B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an antifoaming agent that has excellent foam-breaking and foam-suppressing effects at low concentrations against harmful foaming that occurs in various industries. Antifoaming agents are used in the synthetic rubber industry, synthetic resin industry, paper industry, fermentation industry, dye industry, dyeing industry, paint industry, etc., and are generally used in mineral oil, paraffin,
Silicone oils, metallic soaps, fatty acids, nonionic surfactants or combinations thereof are known. Although some conventional antifoaming agents have excellent antifoaming effects depending on their use, they also have various drawbacks. A particular problem is that the antifoaming agent itself is insoluble or poorly soluble in water. Therefore, they are often used after being dispersed in water, but if they are simply dispersed, they may get mixed into the product, causing various problems. In order to avoid this, there is a method of using an antifoaming agent in an emulsified state using a solvent or an emulsifier, but in many cases, the antifoaming effect is reduced. As a method to improve this drawback, there is a method using an esterified product of polyoxyethylene polyoxypropylene glycol (Japanese Patent Publication No. 45-7973), but it has poor emulsifying properties,
Both antifoaming properties are still unsatisfactory. The present inventors have conducted repeated studies to eliminate such conventional drawbacks and to obtain a self-emulsifying antifoaming agent that forms a stable emulsion in an aqueous system, and as a result, have developed a novel antifoaming agent that meets this purpose. succeeded in obtaining. In other words, the present invention involves an addition reaction of propylene oxide (hereinafter abbreviated as PO) and ethylene oxide (hereinafter abbreviated as EO) to a higher alcohol, and then esterifies the terminal hydroxyl group with a higher fatty acid, resulting in a compound having large hydrophobic groups at both ends. This is an antifoaming agent containing compound (1). RO(C ₃ H ₆ O) _{n (} C ₂ H ₄ O) o Alkyl group or alkenyl group having 7 to 21 carbon atoms; m
is 10 to 50; n is 2 to 15, and the esterification rate is 50
It is mol% or more. ) The compound of formula (1) is usually prepared by adding PO to a higher alcohol.
Polyoxyalkylene glycol monoalkyl ether obtained by block addition polymerization with EO,
Synthesis is possible by direct esterification using higher fatty acids or higher fatty acid chlorides, or transesterification using lower alcohol esters of higher fatty acids, and performance is not affected by differences in synthesis methods. . In the compound represented by the general formula (1), R is an alkyl group or alkenyl group having 8 to 22 carbon atoms, and R' is an alkyl group or alkenyl group having 7 to 21 carbon atoms, but outside this range is not preferred. . For example, when the number of carbon atoms is small, the interfacial adsorption force becomes weak and a sufficient antifoaming effect cannot be obtained, and when the number of carbon atoms is large, the self-emulsifying property becomes poor. The reason why m is limited to 10 to 50, n is limited to 2 to 15, and the esterification rate by fatty acid is limited to 50 mol% or more is as follows.
Antifoaming agents and emulsifying properties are easily affected by the balance between hydrophilic groups and lipophilic groups, and in particular, the antifoaming agent having self-emulsifying properties of the present invention must have an appropriate balance of hydrophilic groups and lipophilic groups. This is because it is necessary. For example, m
If it exceeds 50, the lipophilicity becomes too large, and n
When it exceeds 15, the hydrophilicity becomes too large, and in either case, the antifoaming agent and emulsifying properties are reduced. If the esterification rate is less than 50 mol%, the emulsifying property will be poor. The antifoaming agent of the present invention may be used as it is, emulsified in water, or mixed with kerosene, spindle oil, etc. and emulsified in water. It can also be used in a wide range of water-based applications, especially in the paper industry, paint industry,
Effective against difficult-to-destruct foam in the dyeing industry, fermentation industry, etc. Furthermore, since the product of the present invention has excellent emulsifying properties, it can also be used as a low-foaming emulsifier. Next, an example of producing the compound of formula (1) will be shown. Production example 1 115g of oleyl alcohol and 4 as a catalyst
Take 2 g of caustic potash into an autoclave,
After sealing with nitrogen gas, 1043g of PO was
Addition reaction is carried out at 150°C and 1.0-7.0Kg/ ^cm2 . Then
After addition reaction of 113g of EO under the same conditions, the mixture is sufficiently aged. After neutralizing the catalyst with phosphoric acid and vacuum dehydration, the precipitated crystals were separated and converted to C ₁₈ H ₃₅ O.
1227 g of (C ₃ H ₆ O) ₄₂ (C ₂ H ₄ O) ₆ H was obtained. Next, this compound is transferred to a four-necked flask, 122 g of oleic acid and 4 g of para-toluenesulfonic acid as a catalyst are added, and an esterification reaction is carried out at 100 to 150° C. under a nitrogen stream. After the reaction is complete, the catalyst is neutralized with caustic potash, and after dehydration, the precipitated crystals are separated.
1295g _{of C18H35O} ( _C3H6O ) _{42 (C2H4O)6COC17H33 ( esterification rate} 98 _% ) _was obtained. Production Example 2 In a four-necked flask, add 1227 g of the adduct of PO and EO from Production Example 1 C ₁₈ H ₃₅ O (C ₃ H ₆ O) ₄₂ (C ₂ H ₄ O) ₆ H, 95 g of coconut oil fatty acid methyl ester, and a catalyst. Take 5g of sodium methylate as
After carrying out the transesterification reaction at 120℃, the catalyst was neutralized with phosphoric acid, and after dehydration, the precipitated crystals were separated.
1280 g of C ₁₈ H ₃₅ O(C ₃ H ₆ O) ₄₂ (C ₂ H ₄ O) ₆ COR′ (R′ is a coconut alkyl group; esterification rate 97%) was obtained. Next, the present invention will be explained by examples. Example 1 Using the product of the present invention and the conventional product as antifoaming agents,
Emulsions having two compositions, A and B, were prepared using the formulations shown in Table 1. The emulsion was left for 24 hours and its condition was observed. The results are shown in Table 2, and the emulsion stability of the product of the present invention is good.

【table】

[Table] Example 2 Products of the present invention, conventional products, and emulsified products A and B thereof
A defoaming test was conducted on Add 300 ml of 0.005% rosin soap aqueous solution to a 1 volume graduated cylinder equipped with a ball filter (Kinoshita type) at the bottom.
Each cylinder is maintained at 30°C and vented through a ball filter at a flow rate of 3 per minute for 3 hours. Antifoaming agent is added when the foam volume reaches 300ml after the start of aeration.
100 ppm (in the case of an emulsion product, calculated as a pure antifoaming agent) was added to measure the antifoaming property (foam breaking power), and after further aerating for 3 hours, the sustainability (foam suppressing power) was measured. The results are shown in Table 3, and the product of the present invention has excellent antifoaming properties and durability.

【table】

Claims (1)

[Claims] 1 Antifoaming agent containing the compound of general formula (1) RO (C ₃ H ₆ O) _n (C ₂ H ₄ O) _o X ... (1) (where R is the number of carbon atoms 8-22 alkyl group or alkenyl group; X is hydrogen or COR', R' is a C7-21 alkyl group or alkenyl group; m
is 10 to 50; n is 2 to 15, and the esterification rate is 50
It is mol% or more. )