JP4665281B2 - Aqueous dispersion and aqueous lubricant using the same - Google Patents

Description

【００２１】
｛｝内はランダム状結合を示す。
【００２２】
【表２】

【００２３】
本発明の水分散体である実施例１〜６は、加水分解率が低く、貯蔵安定性に優れるばかりでなく、潤滑性にも優れている。
分子中にエステル結合を持たない比較例１は潤滑性が不十分であり、本発明とは構造の異なるポリエーテルと脂肪酸エステルとからなる比較例２〜４は加水分解率が高く、貯蔵安定性が悪い。
【００２４】
【発明の効果】
本発明の水分散体は、加水分解安定性、貯蔵安定性に優れており、特に水系潤滑剤として用いた場合、潤滑性にも優れている。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous dispersion. More specifically, the present invention relates to water-based lubricants such as rolling oil, forging oil, press oil, drawing oil, cutting oil, grinding oil, and hydraulic oil.
[0002]
[Prior art]
An aqueous dispersion containing a polyether ester compound derived from a polyether compound and a carboxylic acid is used in applications such as lubrication, washing, dispersion, defoaming, oil / water separation, and gelation. However, since the ester hydrolyzes in water, there are problems such as changes in the appearance of the aqueous dispersion during storage or use, and performance such as lubricity and dispersibility is reduced. It was.
For example, Japanese Patent Application Laid-Open No. 52-78661 discloses a rolling oil composition for steel sheet, which contains an ester of polyoxyethylene sorbitol and carboxylic acid. Japanese Patent Laid-Open No. 10-245581 discloses a water-soluble processing oil containing an ester compound of a block copolymer of propylene oxide and ethylene oxide and a carboxylic acid having 2 to 20 carbon atoms. These are esters of hydroxyl groups derived from oxyethylene groups or oxypropylene groups and carboxylic acids, which are hydrolyzed in an aqueous solution and cannot maintain their lubricity, resulting in increased wear on the work tool and the finish of the workpiece. There is a problem that becomes worse. There is also a drawback that appearance changes such as turbidity occur during storage. JP-A-59-166595 shows that a polyether obtained by copolymerizing butylene oxide and ethylene oxide in a random or block form and a polyether derivative derived from a carboxylic acid can be used as a lubricant. However, the specific structure is not shown.
[0003]
[Problems to be solved by the invention]
The present invention provides an aqueous dispersion containing a polyether derivative derived from a polyether compound excellent in storage stability and hydrolysis stability and a carboxylic acid, and an aqueous lubricant excellent in lubricity using the same. The purpose is to do.
[0004]
[Means for Solving the Problems]
As a result of intensive research aimed at overcoming the drawbacks of the prior art, the present inventors have found that an ester derivative of a polyether having a specific structure is excellent in hydrolysis stability and storage stability.
That is, the present invention
[1] An aqueous dispersion of a polyether compound derived from a compound represented by the formula (1) and a carboxylic acid having 6 to 24 carbon atoms,
R [-O- (BO) _h- (AO) _1- (BO) _m- H] _n . . . (1)
(R is a residue or hydrogen atom of a compound having a hydroxyl group having 1 to 24 carbon atoms, AO is an oxyethylene group or oxypropylene group, BO is an oxybutylene group, h, l and m represent the average number of moles added. H is 0 to 30, l is 1 to 200, m is 1 to 30, n is 1 to 6, hn + mn = 1 to 60, and ln = 1 to 200.)
[2] The aqueous dispersion according to claim 1, wherein the polydispersity of the compound represented by the formula (1) is 1.040 or less,
[3] An aqueous lubricant using the aqueous dispersion according to [1] or [2], and
[4] The aqueous lubricant according to [3], wherein the hydrolysis rate of the polyether derivative is 30% or less.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, R in the formula (1) is a residue or a hydrogen atom of a compound having a hydroxyl group having 1 to 24 carbon atoms. Specific examples of the compound having a hydroxyl group include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptane. Linear or branched monohydric alcohols such as decanol, octadecanol, octadecenol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, ethylene glycol, propylene glycol, 1,3-propanediol, 2 -2-3 such as methyl-1,2-propanediol, glycerin, diglycerin, neopentyl glycol, trimethylolethane, trimethylolpropane Compounds having a hydroxyl group, polyglycerol, pentaerythritol, sorbitol, sorbitan, glucose, a compound having four or more hydroxyl groups such as sucrose. These may be used alone or in combination. R is preferably a residue or hydrogen atom of a compound having 1 to 6 hydroxyl groups, and more preferably a residue or hydrogen atom of a compound having 1 to 3 hydroxyl groups.
[0006]
AO is an oxyethylene group or an oxypropylene group. They may be used alone or together. When used together, either random addition or block addition may be used. BO is an oxybutylene group, and BO and AO are block additions.
[0007]
h, l, and m represent the average number of moles added. h is 0-30, preferably 0-10, more preferably 0-5. l is 1 to 200, preferably 5 to 80, and more preferably 10 to 60. m is 1-30, Preferably it is 1-10, More preferably, it is 1-5. n is an integer of 1-6. hn + mn is 1 to 60, preferably 1 to 20. In is 1 to 200, preferably 1 to 70. When h or m exceeds 30, the solubility or dispersibility in water becomes poor. When l or ln exceeds 200, when dissolved in water, the viscosity of the aqueous solution becomes remarkably high and workability is poor.
[0008]
Specific examples of the carboxylic acid having 6 to 24 carbon atoms include hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, Linear or branched saturated carboxylic acids such as octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, hexadecenoic acid, octadecenoic acid, hydroxyoctadecenoic acid, eicosenoic acid, docosenoic acid, octadecaic acid Examples thereof include unsaturated carboxylic acids such as dienoic acid and octadecatrienoic acid. Preferably, a C8-14 linear or branched saturated carboxylic acid such as octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid or the like, or hexadecenoic acid, octadecenoic acid, eicosenoic acid, An unsaturated carboxylic acid having 16 to 22 carbon atoms such as docosenoic acid, octadecadienoic acid, octadecatrienoic acid and the like. These may be used alone or in combination. When the compound of formula (1) has two or more hydroxyl groups, all of them need not be esterified with a carboxylic acid.
[0009]
The polydispersity of the compound represented by the formula (1) is preferably 1.040 or less, more preferably 1.035 or less, and still more preferably 1.030 or less. The polydispersity is an index indicating the molecular weight distribution, and the closer to 1, the narrower the molecular weight distribution and the more uniform the compound. A smaller polydispersity is preferable because hydrolytic stability, storage stability, and lubricity are improved.
[0010]
Polydispersity is generally obtained as an elution parameter of gel permeation chromatography (GPC), and is known to vary greatly depending on the measuring device, column, developing solvent, etc., but is described in the present invention. The polydispersity is calculated by dividing the weight average molecular weight (Mw) and the number average molecular weight (Mn), and is indicated by Mw / Mn. Specifically, SHODEX GPC SYSTEM-11 (trademark, manufactured by Showa Denko Co., Ltd.) as a GPC system, SHODEX RI-71 (Showa Denko Co., Ltd., trademark) as a differential refractometer, and SHODEX KF804L (φ8 mm × as a GPC column) 300 mm, Showa Denko Co., Ltd., trademark) were connected in series, and the column constant temperature bath temperature was 40 ° C., and tetrahydrofuran (THF) was flowed as a developing solvent at a flow rate of 1 ml / min. 0.1 ml of the solution is injected, and the elution curve is analyzed with a BORWIN GPC calculation program (manufactured by JASCO Corporation) to obtain the polydispersity.
[0011]
The compound represented by the formula (1) can be obtained by a general method. For example, a compound having one or more hydroxyl groups is an alkali hydroxide such as KOH or NaOH, or an alkali metal salt such as sodium methylate or sodium ethylate as a catalyst, preferably an alkali metal salt such as sodium methylate or sodium ethylate. A metal salt is added for sufficient dehydration or dealcoholization, and then the reaction temperature is 130 ° C. or lower, preferably 110 ° C. or lower, the reaction pressure is 0.49 MPa (5 Kg / cm ² ) or lower, preferably 0.39 MPa (4 Kg / cm ^2). ) In the following, it can be obtained by adding ethylene oxide or propylene oxide followed by addition of 1,2-butylene oxide. In order to obtain the compound represented by the formula (1) having a low polydispersity, it is preferable to sufficiently perform dehydration or dealcoholization to lower the reaction temperature and reaction pressure. Moreover, the obtained compound represented by the formula (1) can be fractionated by a chromatogram to obtain a polyether derivative having a lower polydispersity.
[0012]
Next, the polyether derivative of the present invention can be obtained by esterifying the compound represented by the formula (1) and a carboxylic acid using an acid or an alkali catalyst. Further, alkali hydroxide is added to the carboxylic acid to sufficiently dehydrate, and then the reaction temperature is 130 ° C. or lower, preferably 110 ° C. or lower, the reaction pressure is 0.49 MPa (5 Kg / cm ² ) or lower, preferably 0.39 MPa (4 Kg / cm ² ). ² ) It can also be obtained by adding ethylene oxide, propylene oxide or 1,2-butylene oxide below.
[0013]
The concentration of the polyether derivative in the aqueous dispersion is preferably 0.01% by weight to 80% by weight, more preferably 0.01% by weight to 20% by weight. If it is thinner than 0.01% by weight, the performance cannot be sufficiently exhibited.
[0014]
The aqueous dispersion of the present invention can be used for applications such as lubrication, washing, dispersion, defoaming, oil / water separation, and gelation. Depending on the application, other compounds can be added as long as the effects of the present invention are not impaired.
[0015]
When used as the aqueous lubricant of the present invention, the polyether derivative may be used alone, but other compounds may be appropriately blended. Such compounds include mineral oils, animal and vegetable oils, carboxylic acid esters, carboxylic acids and their alkali metal or amine salts, sulfurized oleic acid, chlorinated stearic acid, alkyl phosphate esters and other lubricants, monoethanolamine, Examples include organic amines such as ethanolamine, N-dimethylaminoethanol, ethylenediamine, diethylenetriamine, cyclohexylamine, morpholine and adducts thereof, corrosion inhibitors such as carboxylic acids and aromatic carboxylic acids, and silicone-based antifoaming agents. It is done.
The hydrolysis rate of the polyether derivative is preferably 30% or less, more preferably 20% or less.
The hydrolysis rate described in the present invention is determined by the following method. A sample (1 g) was correctly weighed into a rubbed flask, and 100 ml of 0.1% KOH aqueous solution was added thereto. A condenser is attached to the flask and left at 40 ° C. for 2 hours. Thereafter, 25 ml of the solution is withdrawn, a phenolphthalene indicator is added thereto, and titrated with a 0.1 mol / L aqueous hydrochloric acid solution. A blank test is performed in parallel with this test, and the saponification value A is obtained from the results. The hydrolysis rate of the sample is obtained by the following formula.
Hydrolysis rate (%) = A / SV × 100
Note that SV is a saponification value of a sample obtained by heating at 85 ° C. for 6 hours with a 1NKOH aqueous solution.
[0016]
【Example】
The polyether derivatives used in Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1. Lubricity, rust prevention, and hydrolysis rate were evaluated by the methods shown below, and the results are shown in Table 2.
<Polydispersity>
The polydispersity (Mw / Mn) was determined from the weight average molecular weight (Mw) and the number average molecular weight (Mn) obtained from the gel permeation chromatography (GPC) measurement. Specifically, SHODEX GPC SYSTEM-11 (trademark, manufactured by Showa Denko Co., Ltd.) as a GPC system, SHODEX RI-71 (Showa Denko Co., Ltd., trademark) as a differential refractometer, and SHODEX KF804L (φ8 mm × as a GPC column) 300 mm, Showa Denko Co., Ltd., trademark) were connected in series, and the column constant temperature bath temperature was 40 ° C., and tetrahydrofuran (THF) was flowed as a developing solvent at a flow rate of 1 ml / min. 0.1 ml of the solution was injected, and the elution curve was analyzed with a BORWIN GPC calculation program (manufactured by JASCO Corporation) to obtain polydispersity.
[0017]
<Hydrolysis test>
A sample (1 g) was correctly weighed into a rubbed flask, and 100 ml of 0.1% KOH aqueous solution was added thereto. A condenser was attached to the flask and left at 40 ° C. for 2 hours. Thereafter, 25 ml of the solution was taken out, and a phenolphthalene indicator was added thereto, followed by titration with a 0.1 mol / L hydrochloric acid aqueous solution. A blank test was performed in parallel with this test, and the saponification value A was determined from the results. The hydrolysis rate of the sample was determined by the following formula.
Hydrolysis rate (%) = A / SV × 100
Note that SV is a saponification value of a sample obtained by heating at 85 ° C. for 6 hours with a 1NKOH aqueous solution.
[0018]
<Lubricity test>
A polyether derivative shown in Table 1 was prepared to be a 1% by weight aqueous solution, and the friction coefficient of the test solution was measured at a liquid temperature of 25 ° C. using a Kamata pendulum type friction tester.
[0019]
<Storage stability>
A solution obtained by dissolving 10 g of the polyether derivative shown in Table 1 in 90 g of tap water was placed in a test tube with a lid and left at room temperature for 30 days. The state after standing was displayed according to the following criteria.
Judgment criteria ○: Passed No change in appearance.
X: Fail turbidity, two-layer separation, precipitate formation, etc., or viscous.
[0020]
[Table 1]

[0021]
Figures in {} indicate random bonds.
[0022]
[Table 2]

[0023]
Examples 1 to 6, which are aqueous dispersions of the present invention, have a low hydrolysis rate and are excellent not only in storage stability but also in lubricity.
Comparative Example 1 having no ester bond in the molecule has insufficient lubricity, and Comparative Examples 2 to 4 comprising a polyether and a fatty acid ester having different structures from the present invention have a high hydrolysis rate and storage stability. Is bad.
[0024]
【The invention's effect】
The aqueous dispersion of the present invention is excellent in hydrolysis stability and storage stability, and is particularly excellent in lubricity when used as an aqueous lubricant.

Claims (4)

An aqueous dispersion of a polyether derivative derived from a compound represented by the formula (1) and a carboxylic acid having 6 to 24 carbon atoms.
R [-O- (BO) _h- (AO) _1- (BO) _m- H] _n . . . (1)
(R is a residue or hydrogen atom of a compound having a hydroxyl group having 1 to 24 carbon atoms, AO is an oxyethylene group or oxypropylene group, BO is an oxybutylene group, h, l and m represent the average number of moles added. H is 0 to 30, l is 1 to 200, m is 1 to 30, n is 1 to 6, hn + mn = 1 to 60, and ln = 1 to 200.) The aqueous dispersion according to claim 1, wherein the polydispersity of the compound represented by the formula (1) is 1.040 or less. An aqueous lubricant comprising the aqueous dispersion according to claim 1 or 2. The aqueous lubricant according to claim 3, wherein the hydrolysis rate of the polyether derivative is 30% or less.