RU2419639C2 - Method of producing frictional polymer materials - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing frictional polymer materials and can be used in making brake shoes of railway wagons and locomotives, for motor transport, cranes, clutch plates and other articles. The method is realised by processing butadiene or butadiene-nitrile rubber on plastification equipment and mixing the rubber with curing agents, with fibre and powdered filling materials. Aromatic polyamine is simultaneously added with curing additives. The aromatic polyamine is an aniline-formaldehyde condensate consisting of 75% isomers of diaminodiphenylmethane and 3-4 benzene-nuclear primary amines bound by methylene bridges. The fibre filler is pre-saturated for 15 minutes with aqueous solution of epoxy resin which is a product of reacting a mixture of diane and aliphatic epoxy resins with glycols or derivatives thereof, in ratio A:B between 95:5 and 60:40, and then dried to moisture not higher than 1%. The composition of the material contains the following in pts. wt: rubber 100, aromatic polyamine 2-20, sulphur 1-15, thiuram 0.04-2.0, 2-mercaptobenzothiazole 0.3-4.0, fibre filler 15-100, powdered filler 10-100.

EFFECT: invention improves strength characteristics of frictional polymer materials and increases labour safety.

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Description

The invention relates to a method for producing friction polymer materials and can be used in the manufacture of brake pads for railway cars and locomotives, for vehicles, cranes, clutch discs and other products.

Friction polymeric materials and methods for their production on the basis of butadiene rubbers containing vulcanizing additives such as sulfur, tiuram and other sulfur-containing substances, including mineral powders, inorganic fibers and metal shavings are known (see Encyclopedia of Polymers. T.3 M .: ed. “Soviet Encyclopedia ”, 1977, pp. 786-788).

The disadvantages of this method and material are the low strength characteristics of the material due to poor adhesion of the polymer to the fibers, the destruction of the fibers during the mixing of the components, the formation of fibrous dust hazardous to human health, and insufficiently high antifriction properties.

One of the ways to eliminate the above disadvantages is described in patent RU 2.114.338 C1, which consists in the use of polymer fibers subjected to local destructive effects (analogue 2).

The use of organic fibers when mixed with rubber and vulcanizing additives after the destructive treatment of fibers allows to increase adhesion at the rubber-fiber interface, but does not allow to increase the strength characteristics of friction materials and, especially, their heat resistance.

The closest prototype of the proposed solution is a method for producing friction polymer material by processing on plasticizing equipment (rollers) of butadiene or butadiene-nitrile rubbers with an alloy of epoxy resins with 4,4-dioxiphenylsulfone and phenol-formaldehyde resin, followed by mixing with vulcanizing additives and fillers - fibrous see RU 2.175.335, C2 of 04/27/1999)

The above method allows to increase the strength characteristics and wear resistance of the brake mating. However, modern railway transport requires higher strength characteristics of friction materials and improvement of the technology for their production, excluding, in particular, the release of fibrous dust, especially asbestos and fiberglass, which occurs when fibers are used in all known methods, including in the prototype.

The aim of the invention is to significantly increase the strength characteristics of friction polymeric materials, as well as improving labor safety in the process of mixing components on plasticizing equipment - rollers, rubber mixers, etc.

This goal is achieved by the fact that simultaneously with vulcanizing additives, an aromatic polyamine is introduced, which is an aniline-formaldehyde condensate, consisting of 75% isomers of diaminodiphenylmethane and 3-4 benzene primary amines connected by methylene bridges, and the fibrous filler (A) is pre-impregnated for 15 min with an aqueous solution of epoxy resin (B), which is the product of the interaction of a mixture of diane and aliphatic epoxy resins with glycols or their derivatives in the ratio and A: B = 95: 5 to 60:40, and then dried to a moisture content of not more than 1%, wherein the material comprises in parts by weight .:

Rubber one hundred Aromatic Polyamine 2 ÷ 20 Sulfur 1 ÷ 15 Tiuram 0,04 ÷ 2 2-mercaptobenzthiazole 0.3 ÷ 4 Fiberfill, impregnated with water-soluble epoxy resin 15 ÷ 100 Powder filler 10 ÷ 100

Example 1

Preparation of pre-impregnated fibrous filler.

60 parts by weight are loaded into a paddle mixer. chopped glass fiber with a fiber diameter of 13 microns (A) simultaneously with a 50% aqueous solution of water-dispersed epoxy resin ETAL AK-732 (TU 2241-824-18826195-06), which is the product of the interaction of a mixture of diane and aliphatic epoxy resins with polyethylene glycol (B), with a ratio of A: B = 78: 22, calculated on the dry component B. After stirring for 15 minutes, the impregnated fiber enters the dryer to remove water at 100 ° C. The impregnated dry fiber is odorless, elastic pulp, non-dusting, non-toxic, easily disintegrating with little tensile strength. Since the resin does not contain a hardener, the shelf life of the fiber impregnated with it is practically unlimited (tested over 2 years) and therefore it can be prepared in advance.

Obtaining friction material

In the rubber mixer type RSVD 140-20 loaded 100 wt.h. butadiene rubber grade SKD-2 (GOST 14924), 8 parts by weight sulfur, technical ground natural grade 9995, 1 wt.h. Tiurama (GOST 740), 2 parts by weight 2-mercaptobenzthiazole (GOST 739), 45 parts by weight powder filler, consisting of a mixture - alumina (GOST 30558), crystalline graphite (GOST 5279), barite concentrate (GOST 4682) in equal proportions. At the same time loaded 10 parts by weight aromatic polyamine (TU 2473-342-05763441-2001), which is an aneline-formaldehyde condensate, consisting of isomers of diaminodiphenylmethane (75%) and 3-4 nuclear (benzene nuclei) primary amines connected by methylene bridges. Aromatic polyamine is known as the classic hardener of epoxy resins (hot curing), and its amino groups are capable of double bonding to rubbers. Next, 60 parts by weight are loaded into the rubber mixer. fiberglass impregnated with epoxy resin. Stirring is carried out at 80 ° C for 25 minutes. At the end of the production of the mixture, the bottom shutter of the rubber mixer opens, the mass is unloaded and then sent for the manufacture of products by hot pressing at 180 ° C for 25 minutes under a pressure of 31 MPa, followed by heat treatment in a thermostat at the same temperature for 25 minutes.

Examples 2 ÷ 7 are carried out analogously to example 1, but with a change in composition in accordance with table 1.

The properties of the resulting friction material are shown in table 2.

The inventive method can significantly increase the strength characteristics of the resulting friction materials (see table 2) and, possibly, with in-depth studies of the absolute advantages. Fibers impregnated with an aqueous solution of epoxy, unlike non-impregnated fibers, are incomparably better preserved during mixing with rubber. For example, glass fiber on rollers or in a rubber mixer breaks down to sizes up to 0.5 mm long, and impregnated practically retains its original size, which is the most important factor in increasing the reinforcing effect.

Equally important is the elimination of dust when using an aqueous solution of epoxy.

The introduction of an epoxy resin in a material significantly increases the adhesion of rubber to the fiber, because hardener - aromatic amine - interacts with resin and rubber, and all material increases adhesion to the metal frame of the brake pads.

Table 1 The implementation parameters of the proposed method according to examples 2-7 No. Parameter Name Parameter value by examples 2 3 four 5 6 7 one Type and brand of rubber Butadiene SKD-2 Butadiene SKD-1 Nitrile butadiene SKN-18 Nitrile butadiene SKN-26 Nitrile butadiene SKN-18 Nitrile butadiene SKN-18 2 The number of vulcanizing components, parts by weight Aromatic polyamine 12 12 2 twenty 2 2 Sulfur one fifteen 8 8 8 8 Tiuram one one 0.04 2 0.04 0.04 2-mercaptobenzthiazole 0.3 2 four 2 four four 3 Type of fibrous filler and amount, parts by weight Asbestos 15 Basalt fiber 100 Arcelon 60 fiber Polyamide fiber 60 Arcelon 60 fiber Arcelon 60 fiber four The ratio of components A: B 60:40 95: 5 72:28 72:28 72:28 72:28 5 Type and amount of powder filler, parts by weight Electrocorundum 10 A mixture of barite concentrate and graphite 1: 1 Iron Powder 40 Brass shavings 50 A mixture of barite concentrate, graphite and borax 49: 49: 2 A mixture of barite concentrate, graphite and molybdenum oxide 49: 49: 2 90 one hundred one hundred 6 Type of glycol in water-soluble composition Triethylenegly Col Diethylene glycol Polyethylene glycol with mm. 400 Polyethylene glycol with mm. 400 Polyethylene glycol with mm. 300 Polyethylene glycol with mm. 600

table 2 Properties of products obtained from friction polymer materials according to examples 1-7 in comparison with the analogue and prototype No. Name of indicator Indicator value one 2 3 four 5 6 7 Analog 1 Polymer Encyclopedia Prototype RU 2.175.335 one Bending Strength, MPa 90 85 95 93 88 fifteen 65 2 Tensile strength, MPa 70 75 82 78 76 35 37 3 Coefficient of friction according to GOST 10791 0.58 0.56 0.54 0.53 0.56 0.52 0.49 0.38 0.56 four Wear according to GOST 10791 0.08 0,07 0,07 0.08 0.08 0.08 0,07 0.11 0.05

Claims (1)

A method for producing friction polymer materials, including the process of processing butadiene or nitrile butadiene rubbers on plasticizing equipment, followed by their mixing with vulcanizing additives - sulfur, thiuram, 2-mercaptobenzthiazole and a fibrous filler in combination with a powder filler - finely divided mineral or metallic powder that simultaneously with the vulcanizing additives, an aromatic polyamine is introduced, which is an aniline-formaldehyde condensate, consisting of 75% isomers of diaminodiphenylmethane and 3-4-benzene primary amines bound by methylene bridges, and the fibrous filler (A) is pre-impregnated for 15 min with an aqueous solution of epoxy resin (B), which is the product of the interaction of a mixture of diane and aliphatic epoxy resins with glycols or their derivatives, in a ratio of A: B from 95: 5 to 60:40, and then dried to a moisture content of not more than 1%, while the material contains, by weight:
rubber one hundred aromatic polyamine 2-20 sulfur 1-15 tiuram 0.04-2.0 2-mercaptobenzthiazole 0.3-4.0 fiberfill, impregnated with water-soluble epoxy resin 15-100 powder filler 10-100