JPH039996A - Water-based functional solution containing polymer thickener - Google Patents

Abstract

PURPOSE: To obtain a functional fluid showing excellent thickening effect by using a copolymer based on a specified (meth)acrylate as the polymer thickener.

CONSTITUTION: This fluid contains a copolymer comprising 10-90 wt.% 1-4C alkyl (meth)acrylate (e.g. methyl methacrylate), 5-80 wt.% (meth)acrylic acid (e.g. methacrylic acid), 0.1-10 wt.% 8-20C alkyl (meth)acrylate (e.g. dodecyl methacrylate) and optionally at most 20 wt.% compound having one polymerizable double bond, neutralized with a base before or after the polymerization to such an extent that part or all of the acid groups are neutralized and having an average molecular weight of 30,000-300,000 as the polymer thickener.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to poly(meth)acrylate-based water-soluble thickeners for addition to aqueous functional fluids such as hydraulic fluids.

BACKGROUND OF THE INVENTION Various liquids can be used as hydraulic fluids for energy transfer in hydrostatic and hydrodynamic systems. Conventional hydraulic fluids are especially those based on mineral oils or glycols,
Synthetic products such as glycerin, esters or silicone oils. Using water as an inexpensive hydraulic fluid
Although it was initially used for this purpose, its corrosivity and low viscosity were disadvantageous. For special applications where flame-retardant hydraulic fluids are required, water and oil emulsions or
Aqueous solutions of organic substances, low molecular weight compounds such as glycols, and polymeric compounds can be used.

In an era of reduced oil production, and the risk of environmental pollution and destruction due to more or less leakage from hydraulically operated machines, hydraulic fluids with high water content (Hydraulikf l
In other words, the development of so-called high water content hydraulic fluids (HWBHF) with a water content of 80 to 95% is being promoted. Here, water-based hydraulic fluids containing polymeric thickeners became particularly important (Kirk-Osmer Ency
clopedia of Chem-ical Tec
According to European Patent No. 0 057 875 (Vol. 12, p. 715, 3rd edition), (1) a water-soluble polymer incorporating hydrophobic groups, such as an acrylamide/dodecyl acrylate copolymer, and (2) a polymer Thickening agents are known which consist of a hydrophobic group and a water-dispersible surfactant having an associated hydrophobic group;
The ratio of water-soluble polymer to dispersant is adjusted so that under normal conditions, water with a thickener content of 0.5% by weight has a viscosity at least twice that of untreated water.

DE 34 04 537 describes unsaturated, optionally subsequently neutralized carboxylic acids, such as acrylic acid or methacrylic acid, preferably alkyl and alkylaryl groups in ester groups. is bonded to an unsaturated carboxylic acid via a polyglycol ether group, a surface-active unsaturated ester of crotonic acid ester, and a copolymer consisting of one or more acrylic acid or methacrylic ester of an aliphatic C1-CI8 alcohol\ It is described that the combination can be used as an aqueous functional fluid, in particular as a hydraulic functional fluid, a metalworking fluid. The concentration of polymeric active substance that exhibits a sufficient thickening effect in aqueous liquids is between 1 and 20% by weight.

The copolymers proposed here are all prepared on the basis of ethyl acrylate as the main component of the polymer thickener, as can be seen from the numerous examples.

Similarly, (meth)acrylic esters based on ethyl acrylate and having unsaturated carboxylic acids and polyglycol ethers are saturated with alkyl and alkylaryl esters in their ester groups, and are saturated with alkyl and alkylaryl esters in aqueous media. Copolymers which have a thickening effect when added are described in European Patent No. 0 011 806.

Structures with relatively small amounts of surface-active esters co-polymerized result in the association of polymer molecules that dissolve in water and form relatively low molecular weight polymers (molecular weight 10
0000), a significant thickening effect is also achieved. Such thickeners are also called associative thickeners.

Water-soluble derivatives of acrylic acid and methacrylic acid, especially the dialkylaminoalkylamides of these unsaturated acids,
Contains 5-100% by weight, and further contains 0-5% by weight of 06-018 alkyl ester of acrylic acid or methacrylic acid.
Regarding polymeric thickeners for aqueous hydraulic fluids consisting of polymers which may be composed of
Prior art thickeners as polymer additives to aqueous functional fluids, such as hydraulic fluids or metalworking fluids, have been described in 47 421. It does not fully satisfy the requirements from the viewpoint of use, which should be met from the viewpoint of properties and economics. Water-soluble thickeners by copolymerization of surface-active unsaturated esters with other monomers have solved the problem of individual addition of emulsifiers and dispersants compatible with thickeners, but this The proportion of polymerizable emulsifiers is very high, from 5 to 30% by weight, as described in the examples of DE 34 04 537 and EP 0 11 806. Alkyl- or alkylaryl polyglycol ethers of unsaturated carboxylic acids are expensive monomers, impeding the widespread use of thickeners prepared from them for desirable wide applications such as hydraulic fluids.

A discussion of this price can be found in German Patent Publication No. 34-4.
This also applies to the water-soluble polymers described in No. 7 421.

[Means to solve the problem] Surprisingly, water-soluble (meth) which has been on the market for a long time and is inexpensive
The incorporation of long-chain alkyl methacrylates into acrylate-based copolymers provides an alkali-soluble thickener that, due to its property profile, can be used as an additive polymer to aqueous functional fluids, both quantitatively and qualitatively. It was discovered that inexpensive (meth)acrylic monomers can be produced.

The present invention relates to an aqueous functional fluid containing a polymeric thickener, the aqueous functional fluid containing a (meth)acrylate-based copolymer comprising: a) acrylic acid and/or methacrylic acid; C1-C
4 alkyl ester 10-90% by weight b) Acrylic acid and/or methacrylic acid 5-80% by weight C) C8-C of acrylic acid and/or methacrylic acid
They consist of 0.1-10% by weight of monomers of 20 alkyl esters, the acid groups of which have been partially or completely neutralized by addition of a base before or optionally after the polymerization, in which case the co-monomers are Polymer is 30,000-30
Polymerizable compounds having an average molecular weight between 0,000 and having not more than one polymerizable double bond during production
The copolymers, with which up to 20% by weight may be used, are prepared by radically initiated polymerization, preferably by solution polymerization, especially emulsion polymerization. In partially or completely neutralized form, it is used as a thickener with the effect of increasing the viscosity in aqueous systems, preferably aqueous hydraulic fluids and metalworking fluids.

Addition of the copolymer to water in an amount of 5 to 10% by weight, preferably 7 to 10% by weight, thereby reduces the viscosity of the system to 4
Measured at 0℃ lom +++ 2/S, 4'iH: Ha 40
Measured at ℃ 5o-1offi+l+2/S, good! L
< 25~12m++I2/S measured at 40°c
It has the effect of increasing the

The copolymers of the invention, in their partially or completely neutralized form, are surprisingly at least as effective in aqueous systems applying the method of the invention as polymers known from the prior art. Shows thickening effect. Furthermore, the system of the invention exhibits shear stability under its practical conditions, for example in pumps or when used as brake fluids.

The following compounds are used for the preparation of the copolymers: a) CI-c of acrylic acid and/or methacrylic acid
, alkyl esters such as methyl acrylate, isopropyl methacrylate, n-butyl acrylate, n
-butyl methacrylate, imbutyl acrylate, especially ethyl acrylate and methyl methacrylate, especially methyl methacrylate, b) acrylic acid and/or methacrylic acid, especially methacrylic acid, in the acid form and/or salts, and C) acrylic acid and/or or co-C of methacrylic acid
20, preferably C1 (1' alkyl ester of C1B, such as n-octyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, n-decyl acrylate, indecyl methacrylate, octadecyl dodecyl methacrylate) Methacrylate, octadecyl acrylate, the long chain alcohol used here for ester formation, is preferred for use as synthetic alcohol, which is
It is a mixture of various alcohols ranging from 8 to C20. This kind of alcohol is available on the market as ■Lolol (Lolol).
), ■ Alfol, ■ Dopanol (Do) + a-n.

l). An example of a technical alcohol that can be used to make indecyl methacrylate is a mixture of isodecyl alcohol isomers with an average carbon number of 9.9 to 10.3.

For the preparation of the copolymers used according to the invention, the amounts of the heptameric compounds a), b), c) can be varied within a suitable range. This is preferably 20-80% by weight for a), 10-70% by weight for b) and 0.5-5% by weight for C).
More preferably, a) is 30 to 70% by weight, b
) is 20 to 60% by weight, and C) is 0.5 to 3% by weight.

In small amounts, i.e. from 0 to 20%, preferably from 0 to 10%, by weight of the copolymer, other monofunctional a1β- It is possible to use unsaturated, polymerizable compounds, such as styrene acrylonitrile, (meth)acrylamide vinyl ester, and also to substitute other carboxylic acid groups or carboxylic acid groups instead of the acrylic and/or methacrylic acid mentioned under b). It is also possible to use polymerizable compounds, such as itaconic acid, maleic acid, maleic anhydride, crotonic acid anhydride, in the preparation of the copolymer.

In order to suitably use the aqueous functional liquid of the present invention as a thickener, methyl methacrylate, methacrylic acid and 08-C14 alkyl methacrylate should be used in order to obtain an aqueous system with rheological and physicochemical properties required for the purpose of use. in a relatively small amount, i.e. from about 0.5 to about 1
An addition of 0% by weight is required.

(M) Acrylate-based copolymers can be produced by the conventional method of radical polymerization of 7-mer in the form of bulk, solution, or emulsion [H.

Rauch-PunLingam, Th, Voel
ker, Acryl-andMethacrylve
rbindungen, Springers Berlin 1967, especially 203,207.230-233.2
38. See page 327].

Production by emulsion polymerization is particularly preferred. This is done in the presence of an ionic or nonionic emulsifier to emulsify the hexamer and stabilize the resulting polymer latex. Water-soluble polymerization initiators, such as those belonging to alkali or ammonium sulfates or redox systems, are used in amounts of 0.02 to about 2% by weight, based on the comonomers, and the emulsion polymerization is carried out at about 30 to 100°C.

Radically mobile compounds, preferably e.g. 2-ethylhexylthioglycolate, n-butylmercaptan,
Molecular weight modifiers, including monovalent or polyvalent mercaptans such as n- and t-dodecyl mercaptan, pentaerythritol tetrathioglycolate, are used together in the copolymerization to make this copolymer more effective than with unmodified polymers. The coalescence can be adjusted to the desired molecular weight allowing better handling. Mw of the copolymer is 30,000 to 3
0000091 mol, preferably 50000-2000
0091 mol, particularly preferably 50,000 to 20,000
Adjusting the molecular weight according to the invention to be 0 g 1 mole is effective in improving the shear stability of thickeners at the highest possible shear viscosity when used in aqueous functional fluids. Furthermore, this has the advantage that less associative thickener is required to obtain the desired functionality of the functional fluids of the present invention.

The copolymers can be prepared in free acid form or in partially or completely neutralized form. For the purposes of the invention, it is used as a salt with a base, especially as an alkali, ammonium or amine salt.

In order to obtain an excellent or excellent thickening effect, the aqueous functional fluid of the present invention preferably contains 0.2 to 25% by weight of the copolymer prepared from the monomers a), b), c), preferably e.g. contains 0.5 to 20% by weight, particularly preferably,
For example, the metalworking fluid should contain 0.3 to 10% by weight.

The functional fluids of the invention may also contain commonly used and known additives, in particular dispersants, corrosion inhibitors, rust inhibitors and optionally biocides, in the amounts customary for that purpose. .

Conventionally, the molecular weight of the copolymer used in the present invention cannot be measured directly, but only by an indirect method. The molecular weights described in the examples are values based on analogy with methyl methacrylate polymers produced by the same manufacturing method.

Example 1 In a 5 liter reactor equipped with reflux condenser, stirrer and feed equipment, triisobutylphenol sulfate polyglycol ether sodium salt (degree of ethoxylation 7) 0
．． 06g and ammonium belloxonisulfate 1.2g
Dissolve in 120 g of demineralized water at 20°C.

To this solution, while stirring at 80° C., is added an emulsion containing the following components over a period of 3 hours: Methyl methacrylate 1160. h Methacrylic acid soo-og Alkyl methacrylate (mixture of isodecyl alcohol isomers, average carbon number 10) 40,0 g Triisobutyl sulfate phenol polyglycol ether sodium salt 30.0 g 2-ethylhexylthioglycolate 20.09 After adding 1880.09 brine, the mixture is cooled to room temperature. At that time, 1,4-
Diisopropylbenzene hydroperoxide 1.259
and sodium hydroxymethylsulfinate 0.99
Add g. The dispersion is then filtered. The pH of the approximately 40% dispersion is 2.6.

The molecular weight of the copolymer is approximately 5,000,091 moles.

High water content hydraulic fluid (I (WBHF)) Use as thickener: N
After neutralization with aOH, it was diluted to a solid content of 10% by weight.
The aqueous solution is 13.1 m+m2/51 at 40°C and 1 at 50°C.
9.0.5+II+lI2/S at 60°C. Ornm2/
It has a kinematic viscosity of 8, Ortrm2/5 even at 5170 °C (measured according to DIN 51.562). Solid content 5
% aqueous solution at 40°C is 4.5 mm2/S,
The 8% solution is I l-0111112/S. Gear pump (Tyrone Mobile Master Gear Pump P1
5-45, l 4-4 crt+3/W, capacity 3゜51
, delivery volume 15 1/lll1n, rotational speed 3.600, delivery pressure 70 bar, temperature 48 °C, 50% of the normal HWBF anti-wear additive package on a microemulsion basis.
10% during a shear test for 14 hours at 48°C in
The viscosity reduction of the aqueous solution is only 10%.

Example 2 In a 2 liter reactor equipped with a reflux condenser, stirrer and inlet equipment, triisobutyl phenol polyglycol ether sodium sulfate (degree of ethoxylation 7) 0
．． 0.2g and ammonium beloxonisulfate 0.22g
Dissolve g in 430 g of demineralized water at 20°0.

To this solution, while stirring at 80 DEG C., is added an emulsion with the following components over a period of 3 hours: 417.6 g methyl methacrylate 288.0 g methacrylic acid 14.4 g dodecyl methacrylate 10 sulfate triisobutylphenol polyglycol ether sodium salt After adding .8g 2-ethylhexylthioglycolate 7.2g demineralized water 675.0g,
Cool the mixture to room temperature. At that time, 1.4 at 70℃
-diisopropylbenzene hydroperoxide 0.45
g and sodium hydroxymethylsulfinate 0.36
Add 9. The dispersion is then filtered. The pH of the approximately 40% dispersion is 2.8.

The molecular weight of the copolymer is approximately 30,000 to 5,000,091 moles.

When testing a copolymer for use as a HWBHF thickener in an aqueous solution obtained by neutralizing with solid valve lO wt %, 4
Kinematic viscosity at 0.50,60'0 is 15rnm2/s-i
0mm2/S. The decrease in viscosity of a 10% aqueous solution is
Under the conditions described in Example 1, it is 8%.

Example 3 The dispersion preparation and production is similar to that described in Example 1, except that the following additives are used: Methyl methacrylate 11600.09 Methacrylic acid 800.0 g Alkyl methacrylate (mixture of isodecyl alcohol isomers). Average carbon number 10) 40.0g vf, r! I! Triisobutylphenol polyglycol ether-Na salt 30,092-Ethylhexylthioglycolate 2.0g Demineralized water 1850.09 This is added over a period of 3 hours. The pH of the approximately 40% dispersion is 2.
．． It is 6.

The molecular weight of the copolymer is approximately 250,000 to 300,000g1
It is a mole.

This copolymer is particularly suitable for thickening metalworking fluids.

Claims (1)

[Claims] 1. An aqueous functional liquid containing a polymer thickener, comprising (
meth)acrylate-based copolymer component, which comprises: a) C_1 to acrylic acid and/or methacrylic acid;
C_4 alkyl ester 10-90% by weight b) Acrylic acid and/or methacrylic acid 5-80% by weight c) C_8~ of acrylic acid and/or methacrylic acid
Consisting of 0.1-10% by weight of C_2_0 alkyl ester monomers, the acid groups of which are partially or completely neutralized by the addition of base before or optionally after the polymerization, the copolymer is 30,000~300,
characterized in that 0-20% by weight of polymerizable compounds having not more than one polymerizable double bond may be used together with the polymerizable compound having an average molecular weight Mw between 0.000 and Aqueous functional fluid. 2. The aqueous functional fluid according to claim 1, wherein the viscosity of the aqueous functional fluid of less than 10% by weight is between 50 and 10 mm^2/S at 40°C due to the copolymer. 3. The aqueous functional liquid according to claim 1 or 2, wherein the copolymer is a methacrylate copolymer consisting of methyl methacrylate, methacrylic acid, and C_8 to C_1_4 alkyl methacrylate. 4. The aqueous functional fluid according to any one of claims 1 to 3, wherein the functional fluid is a working fluid containing the copolymer in an amount of 0.5 to 20% by weight. 5. The aqueous functional liquid according to any one of claims 1 to 3, wherein the functional liquid is a metalworking liquid containing the copolymer in an amount of 0.3 to 10% by weight. 6. Claims 1 to 5, wherein the functional liquid contains a commercially available additive.
The aqueous functional liquid described in any of the above