GB2088403A - Anti-foaming Phosphosulphurised Agent for Overbased Lubricant Additives - Google Patents

Abstract

The foaming tendency of basic metal complexes especially Calcium Sulphonate when used as lubricant additives is reduced by reacting the complex with a phosphosulphurised polybutene or a hydrolysed derivative thereof, or preparing the complex in the presence of such a polybutene derivative.

Description

SPECIFICATION Improved Basic Metal Complexes This invention relates to new compositions of matter, processes for preparing same, and lubricating compositions containing same. Particularly, it relates to the treatment of basic metal sulfonate complexes, primarily to reduce the foaming tendency of lubricating compositions containing these basic metal complexes.

Basic metal complexes are well-known in the art. They are of utility as lubricant additives, paintdryers, stabilizers for plastics, emulsifiers, rust preventives and the like. They are especially valuable because of their detergent or dispersant properties and their ability to neutralize undesirable acidic bodies formed in e.g. crankcase lubricants under service conditions. For this reason they are one of the most commonly used lubricant additives. The incorporation of basic complexes into lubricating compositions in some cases gives rise to problems. Among these problems is the greater tendency of lubricating compositions containing detergent additives to foam. Another problem is that the lubricant compositions tend to form haze on standing.

United Kingdom Patent Specification 1290251 describes reducing the foaming tendency of basic metal complexes especially basic calcium sulphonates by reaction with high molecular weight substantially aliphatic carboxylic acid or anhydrides. In particular the basic sulphonate is reacted with polyisobutylene succinic anhydrides. We have now found that the foaming tendency may be reduced by reaction with phosphosulphurised polybutene especially hydrolysed phosphosulphurised polybutene.

The present invention therefore provides a process for reducing the foaming tendency of basic metal complexes comprising reacting said complex with a phosphosulphurised polybutene or preparing the metal complex in the presence of said phosphosulphurised polybutene.

As used in the present specification and claims, the term "complex" refers to basic metal salts which contain metal in an amount in excess of that present in a neutral or normal metal salt. The "metal ratio" of a complex is thus the ratio of the total equivalents of metal to the equivalents of metal in the form of neutral or normal metal. The "base number" of a complex is the number of milligrams of KOH to which one gram of the complex is equivalent as measured by titration. Preferably the complex of (A) has a base number of at least 70.

The metal of the complexes may be a Group I or Group II metal such as sodium, potassium, lithium, magnesium, strontium, barium, or calcium. An alkaline earth metal especially calcium barium, or magnesium is preferred. Basic calcium sulfonate complexes are particularly preferred.

Basic metal complexes are known in the art. Those which are contemplated herein include complexes derived from oil-soluble sulfonic acids, oil-soluble carboxylic acids, and mixtures thereof, such as are described in US Patent Nos. 2,501,731; 2,616,904; 2,616,905; 2,616,906; 2,616,911; 2,616,924; 2,616,925; 2,617,049; 2,777,874; 3,027,325; 3,256,186; 3,282,835, 3,384,585; 3,373,108; 3,365,396; 3,342,733; 3,320,162; 3,312,618; and 3,318,809. For purposes of illustration, the disclosures of the above patents are hereby incorporated in the present specification insofar as the complexes useful in this invention are described.

As an example of a particularly convenient process for the preparation of the complexes used, an oil-soluble sulfonic acid, such as a synthetically prepared sulfonic acid, is mixed with an excess of lime (e.g. 10 equivalents per equivalent of the acid) and a promoter such as methanol, heptylphenol, or mixtures thereof, and a solvent such as mineral oil, at 1 5-800C preferably 300C to 600C and the process mass is then carbonated until a homogeneous mass is obtained. Complexes of sulfonic acids, carboxylic acids, and mixtures thereof are obtainable by processes such as are described in US Patent No. 3,312,61 8. Our preferred methods for the production of basic calcium sulphonates are described on Patent Application 2793277 and Canadian Patent 894412.

The term phosphosulphurised polybutene is used to describe the hydrolysed and unhydrolysed materials. The phosphosulphurised material is conveniently prepared by reacting phosphorous pentasulphide with polybutene the reaction being effected by heating preferably under an inert atmosphere for several hours. Typically 1 5 wt% P25B is heated with a polybutene of molecular weight 200 to 2000 preferably 500 to 1300 at a temperature of about 2000C to 2400C for 3 to 6 hours. The material may be hydrolysed by heating in the presence of steam we prefer to heat at from 1 400C to 1 800C in the presence of steam for from 1 to 3 hours. The hydrolysed product may then be stripped with nitrogen. We prefer to use the hydrolysed products since we find this leads to a greater reduction in the foaming properties.

The phosphosulphurised polybutene or the hydrolysed derivative thereof may be included in the reaction for the formation of the basic metal complex alternatively it may be reacted with the basic metal complex after its formation. In this latter instance we prefer that the complex and the phosphosulphurised polybutene be heated together any temperature from 250C up to the decomposition temperature of the process mixture. In some instances, a solvent such as benzene, toluene, naphtha, or mineral oil is desirable in the process. The preferred mixing temperature depends upon the other components present such as the solvent and is at least 250C and below 2500 C. The usual temperature is from 500C to 1500 C.

The amount of the phosphosulphurised polybutene used to treat the complex may be such as to be equivalent to the basicity (as measured by base numbers) of the basic metal complex.

Often it is such as to be equivalent to 90% or less of the basicity of the complex; usually it is such as to be equivalent to 40% or less of basicity. In terms of weight proportions, as little as 0.1%, usually from 1% to 10% and preferably from 3% to 7% (by weight of the complex) is useful to accomplish the treatment.

The present invention is illustrated by reference to the following Examples in which a 300 TBN and a 380 TBN basic calcium carbonate complex were prepared as follows: 300 TBN The following ingredients were charged to a flask provided with a stirrer C24 Alkyl Benzene Sulphonic Acid 350 grams Paraffinic Diluent Oil Viscosity 150 at 1000F 280 grams Calcium Hydroxide 230 grams Water 15 grams Methanol 275 grams Toluene 600 grams the mixture was carbonated for 5 hours at 300C until 100 grams of carbon dioxide had been adsorbed.

The volatile materials were removed by stripping under vacuum and the product obtained by filtration.

380 TBN The following ingredients were charged to a flask provided with a stirrer.

C24 Alkyl Benzene Sulphonic Acid 275 grams Paraffinic Diluent Oil Viscosity 150 at 1000F (Stanco 150) 255 grams Calcium Oxide 100 grams Methanol 180 grams Toluene 265 grams Calcium Chloride 4.4 grams the mixture was carbonated for 5 hours at 500C and a further 135 grams of calcium oxide added and carbonation continued for a further 3 hours with a total of 1 63 grams of carbon dioxide had been absorbed. The volatile materials were removed by stripping under vacuum and the product obtained by filtration.

The foaming tendency of a paraffinic oil of viscosity 600 S.S.U. at 1 000F (SB 600) containing 2 wt% of a 28 wt% active ingredient solution of the 300 TBN calcium carbonate complex, the product containing 100 grams of phosphosulphurised polybutenes and hydrolysed phosphosulphurised polybutenes of varying molecular weights were measured according to ASTM D 892 ml/ml and compared with a product containing no such surfactant; all the oils contained 400 ppm of DOW chemical silicone 200.

The results were as follows: Example 1 Wfth5mass% Co-Suffactant on active ingredient Ca HBNS After After Without Co-Suffactant Carbonation Filtration Co-Suffactant o Phosphosuffudsed Polybutene Polybutene MW 800 130/10 350/40 Polybutene MW 1300 100/T 210/20 ------------------------------------------------------- - - - - - 400/100 o Hydrolyzed Phosphosuffudsed Polybutene Polybutene MW 500 210/50 300/70 Polybutene MW 800 70/0 120/T Polybutene MW 1300 40/0 90/T Example 2 The foaming tendency of the 380 TBN product in which 80 grams of phosphosulphurised polybutene was added immediately after the carbonation step in the manufacturing process and compared with similar products containing hydrolysed phosphosulphurised polybutene and containing no such additive.

All formulations contained 2 wt % of a 20 wt % active ingredient solution of the treated calcium sulphonate and the results were as follows: Co-Surfactant Hydrolyzed Phosphosulfur Phosphosulfur Silicone Polybutene Polybutene Antifoamant 5 mass % 5 mass % None 0 ppm 50/30 40/20 INSOLUBLE 400 ppm T/O T/O Example 3 The solubility of the 300 and 380 TBN products with and without hydrosulphurised polybutene in various oils was measured. The oils ranged from 100% viscosity 600 S.S.U at 1000F base stock through to 100% viscosity 2500 S.S.U. at 1000F base stock, the solubilities were assessed visually with the following results: SB 600/2500 BLENDS in mass 100/0 70/30 50/50 0/100 Ca HBNS-TBN 300 o Without CLEAR CLEAR SLIGHTLY HAZY Co-Surfactant HAZY o With 5 mass % Hydrolyzed CLEAR CLEAR CLEAR CLEAR Phosphosulfurised Polybutene Ca HBNS-TBN 380 o Without HAZY HAZY HAZY HAZY Co-Surfactant o With 5 mass % Hydrolyzed CLEAR CLEAR HAZY HAZY Phosphosulfurised Polybutene

Claims (2)

Claims

1. A process for reducing the foaming tendency of basic metal complexes comprising reacting said complex with a phosphosulphurised polybutene or preparing the metal complex in the presence of said phosphosulphurised polybutene or preparing the metal complex in the presence of said phosphosulphurised polybutene.

2. A basic metal complex whenever produced by a process according to Claim 1.