RU2033322C1 - Lubricant-coating concentrate for metallic moulds - Google Patents

Abstract

FIELD: building materials production. SUBSTANCE: lubricant-coating concentrate for metallic moulds includes components as follows (weight per cent): 35 - 55 filtrate resulted form removing grease from crude paraffin, 8 - 15 non-ionogenic emulsifier, the balance being bottoms of synthetic fatty acids. EFFECT: increased productivity when manufacturing reinforced concrete articles. 1 tbl

Description

 The invention relates to the construction materials industry, namely, the compositions of lubricants and coatings used in the manufacture of concrete, reinforced concrete and gypsum products in metal molds to prevent adhesion of the products to the mold.

Known lubricant for metal molds in the manufacture of concrete and reinforced concrete products, including paraffin distillate vacuum processing of fuel oil 98-99 wt. and bottoms of naphthenic acids 1-2 wt. [1]
Known lubricant for forms containing an extract of selective oil purification of 0.5-0.6 wt. and dewaxed oil P-fractions from slop-wax 0.4-0.5 wt. [2]
A common drawback of these lubricants is the high consumption when lubricating molds due to the high covering ability associated with the high viscosity of oil lubricants.

Known concentrates of lubricants intended after dilution with water to lubricate metal forms in the production of reinforced concrete products, including, by weight. Petroleum oils 30-90, non-ionic emulsifier 2-20, fatty acids 1-5, corrosion inhibitor 0.5-12 [3]
The lack of emulsion lubricants based on this concentrate has a low holding capacity on the vertical surfaces of metal molds, as a result of which a thin layer of lubricant is torn off by concrete mix during concreting. This leads to a sharp increase in the adhesion of concrete to the mold and increases the cost of stripping and cleaning the molds.

The closest technical solution selected for the prototype is a concentrate containing, by weight. bottoms of synthetic fatty acids 1-3, paraffin-containing component paraffin wax 18-24, emulsifier (lime, with an aqueous solution) up to 100, which forms an aqueous emulsion used to lubricate metal forms [4]
The disadvantage of this concentrate is that aqueous emulsions based on it are inverse, i.e. type "water in oil", which dramatically increases its viscosity and hence difficult to form on application, particularly in cold (pour point slack 25-29 ° ^C). As part of this lubricant, a component that contributes to an increase in the holding power of the emulsion on the metal, the bottom residue of synthetic fatty acids, during the preparation of the emulsion enters into chemical interaction with the emulsifier calcium hydroxide, turning into calcium soap of fatty acids, which instead of increasing reduce the holding capacity and the lubricant drains, and also strips off concrete mixture from vertical surfaces, increasing the adhesion of concrete to the mold.

 The proposed concentrate, on the basis of which aqueous emulsions of the lubricant-coating are prepared, eliminates the disadvantages indicated in the known lubricants.

 The coating lubricant concentrate for metal forms, including VAT residues of synthetic fatty acids, a paraffin-containing component and an emulsifier, contains a filtrate for oil de-oiling (slop-vox) as a paraffin-containing component, and a nonionic surfactant as an emulsifier in the following ratio of components, wt.

VAT residues
synthetic fatty acids 30-57
Leachate from
oiling gachey (slop-vox) 35-55
Nonionic
surfactant 8-15
A distinctive feature of the proposed lubricant-coating concentrate is based on the established phenomenon: an aqueous emulsion prepared on its basis, after application to the form and drying, forms a thin sufficiently strong film due to the interaction of bottoms of synthetic fatty acids with the metal of the form, and the slope-vox release agent provides practically the complete elimination of adhesion of concrete to the lubricant on the mold, including for vertical surfaces (side walls of the molds, cassette sheets, etc.). The introduction of other known release agents: waxes, paraffins, ceresins, petrolatum, OPL paste, paraffin wax, various oils, etc. did not allow to achieve a similar result.

 The introduction of a nonionic emulsifier into the lubricant made it possible to preserve the chemical nature of bottoms, in contrast to the known emulsifier lubricants based on inorganic alkaline or alkaline earth metals, saponifying fatty acids in bottoms. This qualitatively changed the behavior of the lubricant on the mold, its holding ability, which allowed the use of direct type emulsions ("oil in water") for lubrication of vertical surfaces while solving the problem of concrete adhesion to the mold.

 Slops-waxes are formed during the production of oils after separation of paraffin-containing raw materials (gache) from the raffinate, followed by multi-stage purification of gache and separation of hard paraffins. Slop woks consist of a mixture of oils and low melting paraffins.

A lubricating coating concentrate is prepared by dosing the required amount of its constituent components, heating them to melt and mixing to a homogeneous state. It turns out a greasy brown paste with a melting point of 40 ^about C.

For use in production, an emulsion of 7-25% concentration is prepared from the concentrate. To do this, concentrate (t 40-60 ^о ) and water (t 40-60 ^о С) are heated, dosed and mixed, without using intensive mechanical or other influences. The emulsion is formed spontaneously by simple mixing of liquids. It turns out a direct emulsion of the oil-in-water type of coffee-milk color, stability of 95-100% for 30 days, pH 6-7, viscosity of 10% concentration with a VZ-243 viscometer (GOST 9070-75) for a diameter of 2 mm is 11 s. The emulsion is non-toxic, odorless, fire and explosion safe.

 The technology of application is as follows.

 Initially, the first 1-3 moldings use emulsions of an increased 15-25% concentration, which is necessary for the formation of a coating film on the form. After that, working compositions of 7-15% concentration are used. The concentration of the emulsion depends on the technological parameters: the rigidity of the mixture, the height of the sides of the mold, the intensity of the vibration, and is selected experimentally.

 Lubrication is applied in any way: mechanically or by air spraying onto a mold cleaned from concrete residues. When applied to vertical forming sheets, the emulsion is firmly fixed on them, due to the interaction of the metal with the still residues of synthetic fatty acids that are part of the emulsion. The resulting brown film hardens as it dries, after which it is no longer washed off with water and is not torn off by the concrete mixture. After concreting, heat treatment, and stripping, the film-coating remains on the mold, however, after repeated concreting without lubrication, it partially goes into concrete, so regular lubrication of the mold is required before each concreting.

 The boundary values of the concentrate are due to the following.

 The lower limit of bottoms of synthetic fatty acids in the concentrate (30%) and the upper limit of slop waxes (55%) are due to a decrease in the film-forming ability of the emulsion from the concentrate and, in this connection, an increase in the adhesion of concrete to the mold. In addition, going beyond these limits of the composition leads to a loss of stability of the emulsion.

 The upper limit of bottoms (57%) and the lower limit of slop waxes (35%) are limited by the increase in the adhesion of concrete to the coating lubricant due to the insufficient content of slop wax release.

The content of the nonionic emulsifier is due to: the lower limit (8%) of the stability limit of the emulsion from the concentrate, the upper (15%) the absence of an additional positive effect from its increase. For some potent non-ionic emulsifiers, the lower limit can be reduced to 4-5%
To test the lubricants, we used a laboratory cassette unit with 4 vertical molding compartments for a product size of 250 x 250 x 40 mm, which were lubricated with the tested compounds, and then were filled with concrete mix of the M150 grade with a seal on the vibrating plate. Next, the cassette was placed in a steaming chamber and steamed according to the standard mode. Lubricants were evaluated by surface quality (the presence of pores and cavities, surface contamination) and by the adhesion of concrete to the mold. Adhesion was evaluated by the size of the concrete growth to the mold after repeated moldings with lubrication of the molding compartments with the same compositions.

 Examples of checking the effectiveness of various compositions of the proposed lubricant and lubricant according to the prototype after 15-fold molding are presented in the table.

 Comparison of the obtained data shows that the compositions of the lubricants obtained from the proposed concentrate provide less (almost complete absence) of adhesion of concrete to the mold (lubricant-coating) in comparison with the compositions of the prototype, which cause strong adhesion and overgrowing of concrete with metal molds.

 The use of grease-coatings from the proposed concentrate will make it possible to make this class of greases universal for vertical and horizontal molds when molding from any concrete classes, reduce labor costs for stripping and cleaning molds, allow solving environmental problems, and reduce their cost and expense.

Claims (1)

 LUBRICATION-COATING CONCENTRATE FOR METAL FORMS, including bottoms of synthetic fatty acids, a paraffin-containing component and an emulsifier, characterized in that as a paraffin-containing component it contains filtrate from oil de-oiling (slop-vox) and non-active emulsifier as an emulsifier the following ratio of components, wt. Leach oil dehydration filtrate (slop-vox) 35 55
Nonionic surfactant 8 15
VAT residues of synthetic fatty acids

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