JP2908904B2 - Defoamer and alkaline detergent composition - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifoaming agent, especially an antifoaming agent which is added to a foaming cleaning solution such as an alkaline cleaning solution to prevent its foaming, and an alkaline cleaning agent containing the antifoaming agent. Regarding.

[0002]

2. Description of the Related Art Alkaline detergents are generally used for cleaning hard surfaces of metals, glass, ceramics, plastics and the like, and surfactants are sometimes added to improve detergent performance. However, since the surfactant has a foaming property, the cleaning liquid foams, resulting in a decrease in work efficiency in cleaning work and wastewater treatment. Also, if the dirt to be removed by washing has a foaming property, foaming failure occurs in the same manner as described above. For example, rolling oil such as beef tallow adheres to a rolled steel sheet after rolling. When the oil is washed with an alkali, the oil is saponified in the washing liquid to form soap and foam.

[0003] Therefore, electrolytic cleaning of metals, metals, glass,
It has been proposed to add an antifoaming agent to a cleaning agent or cleaning liquid used for spray cleaning, immersion cleaning, ultrasonic or other alkaline cleaning of hard surfaces such as ceramics and plastics. As the antifoaming agent, a silicone antifoaming agent such as silicone oil is generally used. However, silicone antifoaming agents do not transfer S to the washed items.
There is a problem of quality deterioration due to adhesion of i ions.

[0004] It has also been proposed to use nitrogen-based antifoaming agents such as ethylene oxide adducts of primary amines in metal detergents (JP-A-62-146285). However, the nitrogen-based antifoaming agent does not necessarily have a sufficient antifoaming effect, and there is concern about the environmental impact of the nitrogen content in the waste water.

[0005] Antifoaming agents that do not contain elements such as Si and N include the addition of higher alcohols in electrolytic cleaning solutions (Japanese Patent Publication No. 60-56439), and the addition of polyether polyols and ethylene oxide/propylene oxide copolymers in alkaline cleaning agents. (JP-A-58-72000) has been proposed. However, the antifoaming effect of these agents is not always sufficient, and the former has a problem of worsening the working environment due to the smell of alcohol.

[0006] In the above, the harmful effects of foaming during cleaning, particularly alkali cleaning, and countermeasures against it have been described. Examples of such cleaning include neutral cleaning for cases where aluminum, printed circuit boards, etc., are corroded by alkali.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antifoaming agent which does not contain elements such as Si and N and has an excellent foam suppressing effect, and an alkaline detergent composition containing the same. be.

[0008]

DISCLOSURE OF THE INVENTION The antifoaming agent of the present invention is characterized by comprising a compound represented by the following chemical formula 3.

[0009]

##STR3## RO(C ₃ H ₆ O)nH (R: alkyl or alkenyl group having 10 to 20 carbon atoms, n: average number of added moles of propylene oxide, 1
number of ~4)

The alkaline detergent composition of the present invention has the following
It is characterized by containing components (a) and (b). (a) an alkaline agent; (b) An antifoaming agent represented by Chemical Formula 3 above.

[0011]

[Embodiments] The compound (antifoaming agent) of Formula 3 is an adduct of an aliphatic higher alcohol with an average of 1 to 4 moles of propylene oxide. The carbon chain length R of the alcohol in chemical formula 3 is 10 to
20, preferably 12-18. Also, R may be saturated or unsaturated, branched or linear.

[0012] If the carbon chain length R of the alcohol is shorter than 8, the defoaming effect will be reduced, while if it exceeds 20, the melting point will be high and the stability of the product will be deteriorated.

The average number of added moles of propylene oxide is 1
If it is less than 4 or more than 4, the antifoaming effect is inferior, and if it is less than 1, the working environment deteriorates due to alcohol smell.

[0014] The antifoaming agent of the present invention may be added to the object to be defoamed, such as a cleaning solution, or may be mixed in advance with other cleaning ingredients to form a formulation.

The amount of the antifoaming agent of the present invention to be added varies depending on the properties of the object to be defoamed and the amount of dirt to be washed, but it is suitable to add it in an amount of 0.1% by weight or more in the washing liquid. . For example, when an object to be washed, such as a steel plate to which beef tallow is attached as dirt, is alkaline washed with a cleaning solution containing 2% by weight of sodium hydroxide as a cleaning component in a cleaning solution containing 0.2% by weight of beef tallow, the antifoaming of the present invention is used. A sufficient defoaming effect can be obtained by adding 0.2% by weight or more of the agent to the cleaning solution.

When formulated as a detergent composition, the antifoaming agent of the present invention is added in an amount of 0.5 to 10% by weight in the composition.
Blending is desirable.

The alkaline cleaning agent of the present invention contains an alkaline agent and the antifoaming agent described above, and further includes known nonionic surfactants, anionic surfactants,
A chelating agent, other builders, etc. can be contained. Nonionic surfactants include polyoxyethylene alkyl ether (alkyl group; octyl, decyl, lauryl, stearyl, oleyl, etc.), polyoxyethylene alkylphenyl ether (alkyl group; octyl, nonyl, etc.), polyoxyethylene/polyoxypropylene block copolymers, and the like. Examples of anionic surfactants include alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkylbenzene sulfonates, carboxylate-based surfactants, phosphate-based surfactants, alkylarylsulfonic acid formalin condensates, and polycarboxylic acid-type surfactants. is mentioned.

As the alkali agent, sodium hydroxide, potassium hydroxide, sodium silicate, sodium carbonate and the like are used, and alkali metal hydroxides are particularly preferred. The alkaline agent is generally blended in the composition in an amount of 20-40% by weight.

Chelating agents include aminocarboxylates such as ethylenediaminetetraacetate and nitrilotriacetate; oxycarboxylates such as gluconate, citrate and malate; oxycarboxylates such as hydroxyethylidenephosphonate. Phosphonates and the like are used.

[0020]

INDUSTRIAL APPLICABILITY According to the present invention, by using a propylene oxide adduct of a specific higher alcohol as an antifoaming agent, it is possible to effectively prevent foaming of foaming liquids such as cleaning liquids.

In particular, it is effective and long-lasting when added to a cleaning agent or cleaning liquid used for alkaline cleaning such as electrolytic cleaning of metals, spray cleaning, immersion cleaning, ultrasonic cleaning, etc. of hard surfaces of metals, glass, ceramics, plastics and the like. Demonstrates a stable defoaming effect for a long period of time.

[0022] Further, in the alkali washing of rolled steel sheets, oils and fats in the stains to be removed by washing are saponified by the alkali to become soap. The antifoaming agent of the present invention can effectively suppress the foaming of the cleaning liquid over a long period of time even when the foaming property of the cleaning liquid is enhanced by the removal of dirt.

[0023]

【Example】

Example 1 A higher alcohol propylene oxide and a commercial defoamer were evaluated for foam suppression.

In this evaluation, 1 liter of test liquid 21 containing an antifoaming agent was placed in a container 11 having a capacity of 3 liters shown in _FIG . It was carried out by blowing in at a rate of 1 liter/minute and circulating the antifoaming agent-containing test liquid 21 with a pump P at a rate of 2.5 liter/minute.

As a test solution, 0.2% by weight of beef tallow was added to a 2% aqueous sodium hydroxide solution, which was heated at 80°C for 8 hours and then slowly cooled. were put into the container 21 as described above, and an experiment was conducted at a temperature of 70°C. Table 1 shows the above results.

[0026]

[Table 1] Average foam height of PO (mm) Defoamer No. Type of higher alcohol Number of moles added* ¹ After 1 minute After 5 minutes After 30 minutes 1 Lauryl (C ₁₂ ) 1.8 50 60 80 2 Lauryl (C ₁₂ ) 2.1 60 70 70 Example 3 Stearyl (C ₁₈ ) 2.2 30 30 50 Example 4 Stearyl (C ₁₈ ) 4.0 30 50 80 Example 5 Oleyl (C ₁₈ ) 2.4 20 30 30 6 2-heptyl 2.5 5 10 40 Undecanol (C ₁₈ ) ratio 7 Nonyl ( _C9 ) 3.0 60 150 - Comparison 8 Lauryl (C12) 5.4 150 - - Example ₉ Oleyl ( _C18 ) 0 60 140 - 10 Pluronic L61 30 150 - Market 11 Tetronic 702 20 140 - Sales 12 Leocon 1020H* ² 20 50 150 products 13 Liquid paraffin (#30) 5 10 150 *1) PO: Propylene oxide *2) Ethylene oxide/propylene oxide adduct of 2-ethylhexanol

Example 2 A detergent composition having the following composition was prepared and used on metal (rolled steel plate) at a detergent concentration of 5%. Note that POE indicates the average number of added moles of ethylene oxide.

(1) Detergent composition A (alkaline detergent) Sodium hydroxide 32 wt% Sodium gluconate 5 wt% _Tetrasodium ethylenediaminetetraacetate 2 wt% Sodium polyacrylate 5 wt% C12 alcohol propylene oxide average 2.5 mol adduct 5 wt% % water balance

(2) Detergent composition B (neutral detergent for cleaning printed circuit boards) Polyoxyethylene (POE=15) nonylphenyl ether 40 wt% Polyoxyethylene (POE=8) nonylphenyl ether ₁₀ wt% C12 alcohol Propylene oxide average 2.5 mol adduct 5 wt% Propylene glycol 25 wt% Water balance

[Brief description of the drawing]

FIG. 1 is an explanatory diagram of an experimental method used in Examples of the present invention;

[Description of symbols]

11 containers 13 paddles 21 Test solution with defoamer M motor P pump

──────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁶ , DB name) C11D 7/26 C11D 7/06 C11D 7/10 C11D 7/60 C11D 3/04 - 3/10 C11D 3/ 22 B11D 19/04 WPI/L (QUESTEL)

Claims (2)

(57) [Claims] 1. An antifoaming agent comprising a compound represented by Formula 1. ##STR00001## RO( _{C.sub.3H.sub.6O} )nH (R: alkyl or alkenyl group having ₁₀ to 20 carbon atoms, n: average number of added moles of propylene oxide, 1
number of ~4) 2. An alkaline detergent composition comprising (a) an alkaline agent and (b) an antifoaming agent represented by formula (2). ##STR2## RO(C ₃ H ₆ O)nH (R: alkyl or alkenyl group having 10 to 20 carbon atoms, n: average number of added moles of propylene oxide, 1
number of ~4)