Method for preparing filling agent for polymeric composition

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a method for preparing a filling agent used in manufacturing polymeric composition materials in making articles for structural and tribotechnical designation. Method involves mixing 0.5-10.0 mas. p. of epoxy diane resin with 100.0 mas. p. of sodium silicate aqueous solution (by dry matter) at temperature 40-60°C. Then the mixture is coagulated with mineral acid taken in the amount providing hydrogen index pH = 4.0-5.0, washed out with water and prepared solid substance as a precipitate is dried. Invention provides enhancing physicochemical and antifriction properties of the polymeric composition.

EFFECT: improved preparing method.

5 ex

 

The invention relates to a process for the production of fillers for polymer compositions and may find application in the production of polymer composite materials for the manufacture of structural parts and tribological purposes.

There is a method of obtaining modified silicon dioxide, including deposition of silica from sodium silicate solution, mixing the resulting suspension with modifier - alkylsilanes sodium or alumosilicates sodium in the amount of 10-40 wt.% the number of silica and drying at 680-750° (RF patent No. 2021203, SW 33/18, 1994). The method allows to obtain a matting tools for varnishes and fillers for rubber products, but few are suitable as fillers for polymeric materials. In addition, the method is technologically complex and high-energy.

There is a method of obtaining modified precipitated silica filler, including deposition of silica, introduction to aqueous suspension of precipitated silica utilizatsionnogo oil, taken in an amount of 5-20 wt.% the number of silica, and drying (patent RF №2107658, SW 33/18, SS 3/12, 1998). The disadvantage of the obtained filler is its unsuitability for use as a filler in many polymers due to the high hydrophobicity and low wettability.

Proceed. of the walls is a method of obtaining silicacontaining material by mixing epoxy Dianova resin with an aqueous solution of sodium silicate and sodium tripolyphosphate, taken in the ratio, parts by weight: epoxy Dianova resin 6-28, sodium silicate 100, sodium tripolyphosphate, 2,6-9,5, followed by exposure of the mixture within 5-15 min and processed by a high frequency current 2460 MHz within 1-2 min at a power 560-790 W (patent of the Republic of Belarus No. 3666, C08J 7/18, 2000). The material obtained after drying and grinding can be used as filler polyethylene, however, due to the high residual alkalinity of the material obtained its use as filler polymers vysokozatratno due to the need for additional technological operations (neutralization, washing and other) and ineffective.

A known method of producing a filler-polymer compositions, including the processing of amorphous silica (Aerosil or white soot) monoethanolamine or triethanolamine, followed by mixing with epoxy Dianova resin, taken in the quantity 11-20 wt.%, and heat treatment at 120-140°With (USSR author's certificate No. 1390231, SC 9/04, SS 1/28, 1988). The method allows to obtain fillers for a wide range of polymers (epoxy, phenolic and furan resins, polyethylene, polypropylene and rubber), however, application of the filler is not always efficient because the epoxy resin on the surface of the filler is in the fully cured state and is not capable of chemical interaction with poly the leader, in which is inserted a filler. In addition, the high concentration of epoxy resin in the composition of the filler (11-25 wt.%) reduce the heat resistance of the compositions, which in this case cannot be higher than the heat resistance utverzhdenii epoxy resin.

The closest in technical essence and the achieved result is a method of producing a filler comprising a mixture of 30 to 45 parts by weight of epoxy Dianova resin and 100 parts by weight of an aqueous solution of sodium silicate (dry residue), the coagulation of the mixture of 20-30%aqueous solution of ferric chloride or copper formate and drying the solid product in the form of sediment (patent of the Republic of Belarus No. 6291, SM 141/02, 141/06, 2004 - prototype). Get the filler has a high heat resistance and can significantly improve the lubricating properties of lubricants. However, with the introduction of the filler in polymeric materials the effect of increasing the friction and physico-mechanical properties appears very weak. In addition, a known filler contains water-soluble compounds, which increases the water absorption of the polymer compositions.

The objective of the invention is the improvement of physico-mechanical and friction properties of polymer compositions.

This object is achieved in that in the method of producing a filler for polymer compositions, the sign is to be eaten, epoxy Dianova resin is mixed with an aqueous solution of sodium silicate (dry residue), the mixture is coagulated and spend drying the obtained solid product in the form of sludge, according to the invention 0.5 to 10.0 parts by weight of epoxy Dianova resin mixed with a 100.0 parts by weight of an aqueous solution of sodium silicate (dry residue) at a temperature of 40-60°the mixture is coagulated with a mineral acid in an amount to provide hydrogen ion exponent pH 4.0 to 5.0, and the resulting solid product in the form of a precipitate before drying washed with water.

The method is as follows. In water 20-50%solution of sodium silicate, which is convenient to use ready-made solutions liquid glass according to GOST 13078-81 injected epoxy Dianova resin and intensively stirred. Mixture at a temperature below 40°With difficult due to high viscosity epoxy resin, largely temperature-dependent, and requires a lengthy process of homogenization.

The mixture of the starting components at temperatures above 60°does not lead to additional positive effect. As a result of mixing a homogeneous emulsion of epoxy resin in an aqueous solution of sodium silicate, with the free alkali present in the solution plays the role of emulsifier, providing high homogeneity of the mixture

Then produce coagulation of a mixture of mineral acid (hydrochloric, sulfuric, nitric). Acid is added in an amount to provide pH of the mixture pH 4.0 to 5.0. The initial pH of aqueous solutions of sodium silicate, as a rule, corresponds to a pH of 11.0 to 12.0. Introduction acid in a smaller number may cause particles of precipitated precipitated silica will contain undecomposed sodium silicate, which is poorly washed with water and degrades the properties of the obtained filler. The decrease in pH<4,0 leads to unnecessary expenditure acid, which is then washed with water.

As a result of coagulation of the mixture falls amorphous fine silica with a developed surface adsorbed macromolecules epoxy associated with silica chemisorptive interaction. With the introduction of epoxy resin in the amount of less than 0.5 parts by weight per 100 parts by weight of sodium silicate, the effect of surface modification of silica is weak, and the introduction of resin is more than 10 parts by weight of the surface of the silica particles is completely shielded by a thick layer of resin, poorly associated with the surface of the filler.

The obtained solid product in the form of precipitate is filtered off and washed with water from the sodium salts formed by the interaction of sodium silicate with a mineral to what slotow and possibly the rest of the acid. When washing the epoxy resin is not washed out of the filler due to its insolubility in water and adsorption interaction with the surface of the silica. The finished filler is dried at a temperature of 60-80°With (to speed up the drying process) or without heating.

The proposed method of producing a filler for polymer compositions was implemented as follows.

Example I (control). In the standard 50%aqueous solution of sodium silicate - sodium liquid glass according to GOST 13078-81 was injected epoxy Dianova resin grade ED-10 in the amount of 0.3 parts by weight per 100 parts by weight of sodium silicate (dry residue) and was stirred at a temperature of 30°to obtain a homogeneous emulsion. In emulsion with continuous stirring in small portions were injected hydrochloric acid according to GOST 3118-77 up until the pH value has not decreased to a pH of 3.6. When this happened coagulation of the mixture. The precipitate was placed in a funnel with a filter and washed with running water, and then dried in a heating Cabinet at a temperature of 60-70°to a moisture content of not more than 1 wt.%.

Example II. 50%aqueous solution of liquid glass was injected epoxy Dianova resin grade ED-10 in the amount of 0.5 parts by weight per 100 parts by weight of sodium silicate (dry residue) and was stirred at a temperature of 40°to obtain a homogeneous emulsion. In Amul is this injected hydrochloric acid to obtain a pH of 4.0. After coagulation of the emulsion obtained precipitate was placed in a funnel and washed with running water, and then dried in a heating Cabinet at a temperature of 60-70°to a moisture content of not more than 1 wt.%.

Example III. A 20%aqueous solution of sodium silicate according to GOST 13079-81 was injected epoxy Dianova resin grade ED-16 in the amount of 5.0 parts by weight per 100 parts by weight of sodium silicate (dry residue) and was stirred at a temperature of 50°to obtain a homogeneous emulsion. The emulsion was injected sulfuric acid according to GOST 4204-77 to obtain a pH of 4.6. After coagulation of the emulsion obtained precipitate was washed with running water and dried at a temperature of 70-80°to a moisture content of not more than 1 wt.%.

Example IV. 50%aqueous solution of liquid glass was injected epoxy Dianova resin grade ED-10 in the amount of 10.0 parts by weight per 100 parts by weight of sodium silicate (dry residue) and was stirred at a temperature of 60°to obtain a homogeneous emulsion. The emulsion was injected nitric acid according to GOST 4461-77 in an amount to provide a pH of 5.0. After coagulation of the precipitate was washed with running water and dried at a temperature of 60-70°to a moisture content of not more than 1 wt.%.

Example V (control). 50%aqueous solution of liquid glass was injected epoxy Dianova resin grade ED-10 in the amount of 12.0 parts by weight per 100 parts by weight of sodium silicate (dry residue) and stirred at which the temperature of 70° C. To the emulsion was injected hydrochloric acid to obtain a pH of 5.5. After coagulation of the emulsion residue was washed with running water, and then dried at a temperature of 60-70°to a moisture content of not more than 1 wt.%.

The filler of the prototype was prepared as follows. In a solution of sodium water glass (100 parts by weight) were administered N,N/-hexamethylendiamine (10 parts by weight), and then epoxy Dianova resin grade ED-10 (34 parts by weight). The resulting emulsion was kept for 10 min, after which coagulate 20% aqueous solution of copper formate (64 parts by weight of dry residue). After coagulation of the solid product in the form of a precipitate was filtered and dried in the air.

The fillers were introduced into polymers, which are used polytetrafluoroethylene (PTFE), GOST 10007-80, low-pressure polyethylene (HDPE) according to GOST 16338-70 and phenol-formaldehyde resin (CFF) brand SF-381 according to GOST 18694-74.

Polymer compositions were made as follows. The fillers obtained in examples I-V and the prototype, was ground in a porcelain mortar and sieved through sieves for separation fraction with a particle size of 40-50 microns. Then the filler was mixed with the PTFE powder and produced samples by cold pressing followed by sintering at a temperature of 370±10°C. In the case of HDPE disperse the filler was mixed with granules of HDPE, and the samples were made by casting p is d pressure. For sample preparation on the basis of the FSF mixed powders of the resin and filler, and samples were made by hot pressing at a temperature of 170±10°and a pressure of 60±5 MPa.

Comparative properties of polymer compositions containing fillers produced by the proposed method and the prototype shown in the table.

Comparative properties of compositions

no songsThe filler according to examplePolymerThe degree of filling, wt.%Breaking stress atThe coefficient of frictionWear, ×10-8
compression, MPatensile, MPa
1I(control)PTFE3028.0-0,166,0
2IIPTFE3031,5-0,143.2
3IIIPTFE3034,0-0,153,0
4IVPTFE3031,0 -0,173,5
5V (test)PTFE3026,0-0,205,0
6PrototypePTFE3024,5-0,206,0
7IIIHDPE1.0-36,50,258,0
8PrototypeHDPE1,0-28,00,32of 17.0
9IIIThe FSF20145--4,5
10PrototypeThe FSF20110--8,0

As follows from the table, the use of filler on the proposed method allows to obtain a polymer composition with a higher performance than the use of filler produced by the method prototype. For example, the mechanical strength of the PTFE with the proposed filler on 27-39% higher than the filler on the prototype, respectively, HDPE 30%, and the FSF by 32%. The coefficient of friction of the floor is the size of the proposed filler on 18-42% lower than with the known filler. The wear rate of the compositions with the proposed filler 1.7-3.0 times lower than that of compositions filled with the prototype, which is especially important for composite anti-friction (bearings) and friction (braking unit) destination.

Control examples I and V show that the output for the claimed range of ratios of components in the manufacture of the filler leads to a decrease in mechanical strength and wear resistance of the obtained polymer compositions. Thus, only complete combination of distinctive signs required to achieve a positive result.

Breaking stress in compression was determined according to GOST 4651-82 and tensile GOST 11262-80 on the machine ZD-10. Friction tests were carried out on the machine friction SMC-1 scheme "shaft-liner" at a load of 1.0 MPa and a sliding speed of 0.5 m/s Liner was made of the investigated material. As the shaft used steel roller 45 with a diameter of 40 mm with the original roughness Ra≤0,32 mm.

The proposed filler was used for the manufacture of polymer compositions based on PTFE, which were tested as bearings tensioners belt drives combine harvester VALVE-10 "Polesie" PA "Gomselmash". Developed material in bench test the s showed high performance characteristics, that confirms the compliance of the proposed technical solution the criterion of "industrial applicability".

A method of producing a filler for polymer compositions, namely, that epoxy Dianova resin is mixed with an aqueous solution of sodium silicate (dry residue), the mixture is coagulated and spend drying the obtained solid product in the form of sediment, characterized in that 0.5 to 10.0 parts by weight of epoxy Dianova resin mixed with a 100.0 parts by weight of an aqueous solution of sodium silicate (dry residue) at a temperature of 40-60°the mixture is coagulated with a mineral acid in an amount to provide hydrogen ion exponent pH 4.0 to 5.0, and the resulting solid product in the form of a precipitate before drying washed with water.



 

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