CH423060A - Suitable as a lubricant, hydraulic oil or sealing grease, flowable mixture with improved viscosity properties - Google Patents

Description

  

      Flowable mixture suitable as lubricant, hydraulic oil or sealing grease with improved viscosity properties The generally used oils and greases suitable as lubricants, hydraulic oils and sealing greases have the disadvantage that their viscosity decreases with increasing temperature. With these oils and fats, however, special emphasis is placed on the viscostatic. Properties, i.e. a reduced viscosity dependence on temperature.

   The viscosity-temperature behavior could already be improved by adding oil-soluble, linearly built macromolecular substances. Oils improved in this way show, compared with the starting oil, a smaller but still very strong decrease in viscosity with increasing temperature. With an additive according to the present invention, this mostly disadvantageous viscosity-temperature behavior can not only be advantageously changed in the practically possible temperature range, but even reversed.

   Furthermore, the addition of intrinsic viscosity and, in the case of a higher dosage, the occurrence of a flow limit; this means that the viscosity decreases with increasing shear stress or the mixture only begins to flow at a certain shear stress.



  The present invention relates to flowable mixtures suitable as lubricants, hydraulic oil or sealing grease with improved viscosity properties, which are characterized in that they contain a three-dimensionally swellable, macromolecular substance in a swollen state and in finely divided form, the degree of swelling in the to improving mixture at room temperature is at least 1.



  Weakly crosslinked macromolecular substances can be produced in the usual way by polymerization, polycondensation, polyaddition or by converting natural substances. Weakly crosslinked macromoleculars produced on a purely synthetic route are given due to the appropriate controllability of the production reactions before given; Another advantage is that they occur very evenly. The weak crosslinking can be achieved by using polyfunctional compounds in the production of the macromolecular substance or by subsequent reaction with polyfunctional substances.

   The degree of crosslinking can be adjusted as required by the amount of built-in polyfunctional substances. It should be selected so that the maximum degree of swelling of the macromolecular substance in the liquid in question is at least 1. The maximum degree of swelling indicates how many parts by weight of swelling agent 1 part by weight of solvent-free macromolecular substance can absorb.

   It is measured by allowing a certain amount of the substance in question to swell until an equilibrium is reached, separating off excess swelling agent and then determining the weight gain.



  Instead of using the maximum degree of swelling, the optimal concentration of slightly offset macromolecular substances can also be determined from the curve that is created by plotting the logarithm of the viscosity against the logarithm of the concentration. This curve is S-shaped. The optimum concentration is on the abscissa, on which the curve has the greatest negative curvature after an initial positive curvature.



  The weakly crosslinked macromolecular substances can preferably be produced by polymerization or copolymerization of olefinically unsaturated compounds in the presence of crosslinking agents. Suitable olefinically unsaturated compounds are, for.

   B. olefins such as ethylene, propylene, butylene, butadiene, isoprene; Styrene, alkylstyrenes, vinyl toluene, vinyl esters, vinyl ethers, esters of unsaturated carboxylic acids such as.

   B. acrylic acid, methacrylic acid, crotonic acid, fumaric acid or maleic acid. Suitable crosslinking agents are connections with at least two polymerizable double bonds, eg.

   B. divinylbenzene, acrylic and methacrylic acid derivatives of polyvalent or unsaturated alcohols or amines such as glycol dimethacrylate, allyl methacrylate, methylene bis acrylamide, ss allyloxy ethyl acrylate, ss-vinyloxy ethyl acrylate, anhydrides of unsaturated metals with polyvalent carboxylic acids or salts thereof ,

   also polymers with olefinically unsaturated groups, e.g. B. the polymers and copolymers of butadiene or isoprene with a high content of vinyl groups, or unsaturated polyester z.

   B. from glycol and maleic acid, or the polymers produced by anionic or cationic polymerization of allyl acrylate, vinyl acrylate, ss-vinyloxyethyl acrylate or methacrylate. Under certain polymerization conditions known per se, monomeric conjugated diolefins such as.

   B. butadiene and isoprene can be effective as crosslinking agents. In certain cases, weak networking can also be achieved by using polyfunctional and unsaturated starters and / or transfer regulators. Crosslinking is also possible through chemical aftertreatment or high-energy radiation. In addition to the appropriate degree of crosslinking, the macromolecular substances should have good aging resistance.



  The fine particles required can be produced as desired. In a simple way they are z. B. by grinding piece polymers he keep. Milling can also be done in a colloid mill in the swollen state. The finished composition can also be produced by solution polymerization in the low-volatility swelling agent and subsequent grinding.

       Through emulsion polymerization or pearl polymerization, the polymers are created directly in the required particle size. Aqueous polymer dispersions can be mixed as such with the low-volatility swelling agent while the water is evaporated at the same time or afterwards. Or the polymers are first isolated by precipitation or drying and then added to the swelling agent.

   Particularly suitable and therefore preferred are polymers in the form of spherical particles, such as those obtained, for example, by emulsion, bead or precipitation polymerization; Such particles have a better stability against mechanical degradation due to their Kugelge structure and also cause an increased lubricating effect.

   When choosing the polymerisation process, it should be noted that the solution polymerisation requires larger amounts of crosslinking agent than block or bead polymerisation in order to obtain an equally strong swelling of the crosslinked polymers.



  The average particle size of the macromolecular substance should be less than about 0.1 mm. Particle sizes of 0.01 to 10, u. A certain proportion of larger particles is generally not harmful, especially since these are further comminuted during use.



  Suitable swelling agents are particularly low-volatility substances or mixtures of substances which by themselves have a good lubricating effect or good properties as hydraulic oils or sealing greases and also good resistance to aging, in particular aliphatic, cycloaliphatic and aromatic oils and fats and esters of fatty acids or Polycarboxylic acids, polyethers and silicone oils. The properties of these oils and fats can be enhanced by additives such as antioxidants, dispersants and detergents,

      Soaps, rust inhibitors, linear (soluble) polymers, graphite or molybdenum sulfide can be further improved.



  The choice of the weakly crosslinked macromoleculars depends on the swelling agent used. The combinations are to be chosen so that the macromoleculars used are strongly swollen. The selection can be made on the basis of simple experiments or on the basis of the known solubility behavior of the uncrosslinked macromolecular substances.



  Particularly interesting properties show combinations in which the swelling agent is a so-called bad solvent for the macromolecular substance in question. In this case, the swelling of the weakly crosslinked macromolecular substance increases sharply with increasing temperature, and the result is a viscosity-temperature behavior that is reversed to the previously known.



  Optimal viscostatic effects are achieved when the weakly cross-linked macromolecular substance is swollen with approximately the amount that corresponds to a maximum swelling, or with less swelling agent. With the addition of more swelling agent, the viscostatic effect gradually decreases.



  <I> Preparation 1 </I> Production of cross-linked polystyrene by bead polymerisation In 2875 ml dist. Water containing 2 g of a wetting agent (secondary alkyl sulfate) and 25 g of a high molecular weight copolymer of sodium methacrylate and methyl methacrylate dissolved, the mixture of 750 g of styrene, 3.75 g of butanediol dimethacrylate and 7,

  5 g of benzoyl peroxide are intimately dispersed with a hochtou ring mixed siren. The mixture is immediately warmed to 45 with stirring. Over the course of an hour, the temperature is increased to 90 ge and left at this level for 7 hours. It is then cooled, acidified with hydrochloric acid and the very fine-grained bead polymer is filtered off with suction and dried. Yield 685g. The somewhat baked-together polymer is crushed in a ball mill.



  <I> Preparation 2 </I> Production of cross-linked polystyrene by emulsion polymerization 100 g of stearic acid in 3000 g of distilled water in a stirred vessel. Water and 24 g of 25% ammonia dissolved with heating. After complete dissolution, 8 g of potassium persulfate, 12 g of sodium hydrogen carbonate and a mixture of 1996 g of styrene and 4 g of glycol dimethacrylate are added, and the mixture is polymerized at 60 for 8 hours under nitrogen.

    A very finely divided dispersion with a dry residue of 40% is obtained. For further processing, the polymer can be isolated by drying the dispersion and ground. <I> Preparation 3 </I> Production of crosslinked polynonyl methacrylate by emulsion polymerization A mixture of 150 g dist. Water, 5 g sodium stearate, 0.2 g potassium persulfate, 0.3 g sodium hydrogen carbonate, 99.8 g nonyl methacrylate and 0,

  2 g of glycol dimethacrylate is heated in a stirred vessel under nitrogen. The temperature is kept at 50 for 18 hours, at 60 for 1 hour, at 70 for 5 hours and at 95 for 3 hours. The result is a very finely dispersed dispersion with a dry content of 41%.

    <I> Example 1 </I> The bead polymer produced as preparation 1 was swollen in concentrations of 5, 9 and 15% by weight in Shell-Dutrex 3. (Dutrex 3 is an aromatic mineral oil extract; flash point 157, pour point -35, aniline point -9.2.) For complete swelling of the polymer, the mixtures were heated to 120 with stirring. The viscosity of the mixtures was measured at 20, 50, 100 and 150 with a Brookfield viscometer type HBT at various speeds.

   The results are shown in FIGS. 2-4. Fig. 1 shows the viscosity of the pure oil.



  <I> Example 2 </I> The polymer produced as preparation 1 was mixed in mixtures of Dutrex 3 and Shell Carnea Oil 31 (specific weight 0.937, flash point 187, pour point -30, viscosity at 50 4.5 Engler) according to the following table swollen and measured as in Example 1. The results of the viscosity measurements are shown in FIGS. 5 to 8.

    
EMI0003.0048
  
    <I> Composition <SEP> (wt.%) </I>
<tb> Dutrex <SEP> 3 <SEP> Carnea <SEP> oil <SEP> 31 <SEP> Polystyrene <SEP> Fig.
<tb> 90 <SEP> 10 <SEP> - <SEP> 5
<tb> 85 <SEP> 10 <SEP> 5 <SEP> 6
<tb> 81 <SEP> 10 <SEP> 9 <SEP> 7
<tb> 76 <SEP> 10 <SEP> 14 <SEP> 8 <I> Example 3 </I> About 130 parts by weight of Shell Dutrex 3 contained 25 parts by weight of the polystyrene dispersion produced as preparation 2 added dropwise with stirring. The water contained in the dispersion evaporates immediately with vigorous foaming. The swollen polymer is distributed extremely finely in the oil. Then it is heated to 180 for a short time.



  The homogeneous mixture has a polymer content of 10%. A sample is precipitated by dilution with petroleum ether and dried. The isolated polymer shows a maximum swelling of 20 to 21 g benzene / g polymer at 20 in benzene. 10% of the polymer is soluble in benzene.



  The viscosities of the mixture with Dutrex 3 were measured at 20, 40, 60, 80 and 100 with the Brookfield viscometer HBT, spindle 4. The results are shown in FIG.



  Example 4 In 200 parts of Shell Vitrea-Oel 27 (paraffinic lubricating oil refined with solvents, specific gravity 0.870, flash point 2211, pour point -12, viscosity at 50 4.5 Engler) are 82 parts at 120 the polynonyl methacrylate dispersion prepared as preparation 3 is stirred in. A homogeneous mixture with a polymer content of 14% is obtained. By adding more Vitrea-Oel 27, this is diluted to a polymer content of 2 to 12%.

   The viscosity measurements with the Broökfield viscometer HBT at 20 and 100 gave the following values:
EMI0003.0081
  
    Polymer content <SEP> measuring body <SEP> rpm <SEP> viscosity <SEP> poise
<tb> o / <SEP> 20 <SEP> 100
<tb> <U> 0 </U>
<tb> 14 <SEP> T-A * <SEP> 1 <SEP> 450 <SEP> 450
<tb> 2.5 <SEP> 320 <SEP> 320
<tb> 5 <SEP> 230 <SEP> 180
<tb> 14 <SEP> spindle <SEP> 2 <SEP> 5 <SEP> 280 <SEP> 310
<tb> 10 <SEP> 180 <SEP> 170
<tb> 20 <SEP> 130 <SEP> 100
<tb> 12 <SEP> T-A <SEP> 1 <SEP> 130 <SEP> 160
<tb> 2.5 <SEP> 96 <SEP> 96
<tb> 5 <SEP> 80 <SEP> 64
<tb> 12 <SEP> spindle <SEP> 2 <SEP> 5 <SEP> 90 <SEP> 110
<tb> 10 <SEP> 64 <SEP> 68
<tb> 20 <SEP> 48 <SEP> 43
<tb> 10 <SEP> T-A <SEP> 1 <SEP> 32 <SEP> 24
<tb> 2,

  5 <SEP> 25 <SEP> 20
<tb> 5 <SEP> 22 <SEP> 16
<tb> 10 <SEP> spindle <SEP> 2 <SEP> 5 <SEP> 29 <SEP> 29
<tb> 10 <SEP> 23 <SEP> 20
<tb> 20 <SEP> 19 <SEP> 13
EMI0004.0001
  
    Polymer content <SEP> measuring body <SEP> rpm <SEP> viscosity <SEP> poise
<tb> 20 <SEP> 100
<tb> <U> 0 </U>
<tb> 8 <SEP> spindle <SEP> 2 <SEP> 5 <SEP> 10 <SEP> 4
<tb> 10 <SEP> 8.6 <SEP> 3.5
<tb> 20 <SEP> 7.8 <SEP> 2.6
<tb> 6 <SEP> spindle <SEP> t <SEP> 5 <SEP> 3.6 <SEP> 10 <SEP> 3.5 <SEP> 0.6
<tb> 20 <SEP> 3.2 <SEP> 0.6
<tb> 50 <SEP> 3.2 <SEP> 0.7
<tb> 4 <SEP> spindle <SEP> t <SEP> 5 <SEP> 1.2 <SEP> 10 <SEP> 1.9 <SEP> 20 <SEP> 1.8 <SEP> 50 <SEP> 1 , 8 <SEP> 100 <SEP> 1.8 <SEP> 4 <SEP> spindle <SEP> <B> 1 </B> <SEP> 5 <SEP> 2.4 <SEP> 0.32
<tb> 10 <SEP> 2.4 <SEP> 0.24
<tb> 20 <SEP> 2.3 <SEP> 0.28
<tb> 50 <SEP> 2.2 <SEP> 0.33
<tb> 100 <SEP> 2,3 <SEP> 0,

  42
<tb> 2 <SEP> spindle <SEP> t <SEP> 10 <SEP> 0.6 <SEP> 20 <SEP> 0.8 <SEP> 50 <SEP> 1.0 <SEP> 0.32
<tb> 100 <SEP> 1.05 <SEP> 0.45
<tb> 2 <SEP> spindle <SEP> l <SEP> 5 <SEP> 0.96 <SEP> 10 <SEP> 1.12 <SEP> 20 <SEP> 1.12 <SEP> 0.08
<tb> 50 <SEP> 1.20 <SEP> 0.19
<tb> 100 <SEP> 1.20 <SEP> 0.28
<tb> T-A <SEP> is <SEP> a <SEP> cross-shaped <SEP> stirrer, <SEP> its <SEP> crossbar
<tb> 48 <SEP> cm <SEP> long <SEP> is.

 

Claims (1)

PATENT CLAIM I A flowable mixture suitable as a lubricant, hydraulic oil or sealing grease with improved viscosity properties, characterized in that it contains a three-dimensionally swellable, macromolecular substance in a swollen state and in finely divided form, the degree of swelling of which in the mixture to be improved at room temperature is at least 1 amounts. SUBCLAIMS 1. Mixture according to patent claim I, characterized in that it contains a weakly crosslinked, finely divided polymer or mixed polymer of an olefinically unsaturated compound. 2. Mixture according to claim I, characterized in that it contains a polymer as weakly crosslinked macromolecular substance. 3. Mixture according to dependent claim 2, characterized in that it contains a weakly crosslinked, finely divided polymer or copolymer of an acrylic or methacrylic acid ester. 4. Mixture according to claim I, characterized in that it contains as a base a flowable substance which is itself suitable as a lubricant or a substance mixture suitable as a lubricant. 5. Mixture according to patent claim 1, characterized in that it contains a weakly crosslinked macromolecular substance, the maximum degree of swelling of which increases with increasing temperature, the increase in swelling being reversible. 6. Mixture according to claim I, characterized in that it contains at least as much swelling agent that the weakly crosslinked macromolecular substance is in a completely swollen state. 7. Mixture according to dependent claims 5 and 6. PATENT CLAIM II Process for the preparation of a mixture suitable as a lubricant according to patent claim I, characterized in that a liquid is converted into a mixture with finely divided, weakly crosslinked, three-dimensional swellable macromolecular substances. SUB-CLAIM B. Method according to claim II, characterized in that the weakly cross-linked macromolecular substance is made to swell in the liquid in a finely divided state. 9. Method according to claim II, characterized in that a substance suitable as a lubricant is used as the liquid. 10. The method according to claim II, characterized in that such weakly crosslinked macromolecular substances are used whose ma ximal degree of swelling increases with increasing temperature, the increase in swelling being reversible.