RU1776268C - Potting composition - Google Patents

Abstract

SUMMARY OF THE INVENTION; the sealing composition includes, but not limited to, a divinyl rubber-based urethane prepolymer containing 2.8-4.2% isocyanate groups 100, carbon black 26.0-65.0, triethanolam N 1.2-3.0, and hydroxyl-terminated divinyl rubber having the same microstructure of the diene chain and molecular weight with a urethane prepolymer of 7.5-22.0. The composition may contain titanium dioxide TU2 in an amount of 5.0-15.0 parts by weight 100 ma.ch. urethane prepolymer. A composition is prepared by mixing a urethane prepolymer with a pre-prepared mixture including divinyl rubber, triheganolamine and carbon black. Curing is carried out at 23 ± 2 ° C for 48 hours. Conditional tensile strength, MPa, when cured without moisture, 2.5-2.6; bond strength with rubber based on non-polar rubbers, kN / m 1.6-2.1.2 tab. with C

Description

The invention relates to the production of a sealing composition based on liquid rubbers that can be vulcanized at a normal temperature of (15-35) ° C and can be used to seal rubber, rubber-metal, rubber-plastic, concrete products and to carry out various types of repair work, including repair of conveyor belts and technological equipment.

In recent years, there has been an expansion of applications and an increase in requirements for sealing materials. It is necessary that the sealant has sufficient viability to seal large items and long seams, and

At the same time, it quickly cured. Sealant components should be slightly toxic. In a number of cases, for example, during intracutural sealing of products, when sealing deep cuts of conveyor belts, etc. the sealant must be cured without air.

A two-component sealant based on a urethane prepolymer obtained from divinyl rubber and containing isocyanine groups in an amount of 2.8-4.2%, including carbon black P803, triethanolamine and tetramethylthiuram disulfide, is known. The sealant is used for surface sealing and repair of rubber, rubber-metal and rubber-plastic products. GerG

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ABOUT

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Methics are poor adhesion to rubber based on non-polar rubbers, long cure time (3-5 days).

A known composition based on vinyl hydroxide end-hydroxyl groups including polyisocyanate, triethanolamine, a filler (cement, asbestos, aerosil, etc.) and intended for construction. The composition cures within a few hours, but contains a toxic hardener - polyisocyanate and does not adhere to non-polar rubber based rubbers.

Closest to the invention in technical essence is a sealant comprising a divinyl rubber urethane prepolymer containing isocyanate groups in an amount of 2.8-4.2%, triethanolamine, carbon black P803, possibly titanium dioxide (3). The sealant is cured with triethanolamine or a paste based thereon. A disadvantage of the sealant is low adhesive and cohesive strength, long cure time, low pot life after mixing of the components, and low processability due to the inconvenient ratio of the components.

The main and main disadvantage of the prototype is the very low cure rate without access to air moisture, for example, during the intra-seam sealing of products, sealing of threaded joints, sealing of deep cuts of conveyor belts and low adhesion to rubbers based on non-polar rubbers.

It is an object of the invention to provide a sealing composition capable of quickly curing without moisture in the air, having sufficient strength and good adhesion to various materials, including non-polar rubber rubbers.

This goal is achieved in that the sealing composition comprising a divinyl rubber urethane prepolymer containing 2.8-4.2% isocyanate groups, carbon black, triethanolamine, further comprises a liquid divinyl rubber with terminal hydroxyl groups in the following ratio components, parts by weight;

Urethane prepolymer

based on divinyl

rubber containing

isocyanate groups in

the amount of 2.8-4.2% 100.0

Divinyl rubber with

terminal hydroxyl groups 26.0-65.0

Triethanolamine 1.2-3.0

Carbon black 7.5-22.0

The sealing composition may contain titanium dioxide in an amount of 5.0-15.0 parts by weight. per 100 parts by weight urethane forlolymer based on divinyl rubber. containing isocyanate groups in an amount of 2.8-4.2%, to improve the quality of mixing of the components.

GOST and TU:

Urethane forpo-5 SKU-DF-2 gauge on

divinyl basis

rubber containing

isocyanate groups

in the amount of 02.8-4.2% of TU 38103451-79

Divinyl rubber

hydroxyl terminated

SKD-GTRATU 38.103315-85

5 Triethanolamine TU 6-09-2448-86

Titanium Dioxide GOST 9808-84

Technical

carbon GOST 7885-86

Samples for testing the adhesive properties of the compositions were prepared from a general-purpose conveyor belt with lining rubber based on non-polar rubber SKI-3.

The curing of the compositions was carried out 5 at a temperature of (23 + 2) ° C for 48 hours

The bond strength of the compositions with the conveyor belt during delamination was determined according to GOST 6768-75. Samples of the conveyor belt for determining the bond strength with 0 outer lining and rubber-fabric lining during delamination were prepared according to GOST 20-85, section 4. The surface of the belt samples was roughened with corundum sandpaper No. 50-60, 5 then degreased with acetone, followed by drying at 23 ° C for 10 minutes

The compositions were put with a spatula on 2/3 of the surface of the tape samples, then they were joined in pairs and rolled on a roll 5 times in both directions.

The invention is illustrated by examples 1-10 (example 1 by a known method). Table 1 shows the composition of compositions 5, in table. 2 - properties of compositions.

Example 1. The composition was prepared by mixing SKU-DF-2 urethane prepolymer based on divinyl rubber containing isocyanate groups in the amount of 2.8-4.2%, with carbon black P803 and hardener triethanolamine.

Examples 2-5. The compositions were prepared by mixing SKU-DF-2 urethane prepolymer based on divinyl rubber containing 2.8-4.2% isocyanate groups with SKD-GTPA divinyl rubber, P803 carbon black and triethanolamine in different ratios.

Examples 6-7. The compositions were prepared by mixing the SKU-DF-2 urethane prepolymer based on divinyl rubber containing isocyanate groups in an amount of 2.8-4.2%, additionally containing titanium dioxide, with SKD-GTPA divinyl rubber, P803 carbon black and triethanolamine.

Example 8. The composition was prepared by mixing the SKU-DF-2 urethane prepolymer based on divinyl rubber containing isocyanate groups in the amount of 2.8-4.2% with a vulcanizing paste including PDI-1 rubber, carbon black P803 and triethanolamine .

Example 9 A composition was prepared by mixing a SKU-DF-2 urethane prepolymer based on divinyl rubber containing 2.8-4.2% isocyanate groups with a vulcanizing paste comprising laprol 503 polyether, P803 carbon black and triethanolamine.

Example 10 A composition was prepared by mixing a SKU-DF-2 urethane prepolymer based on divinyl rubber containing 2.8-4.2% isocyanate groups with a vulcanizing paste including 1,4-butanediol, P803 carbon black and triethanolamine.

As can be seen from the table. 2 (examples 2-7), introduction to a sealing composition comprising a divinyl rubber urethane prepolymer containing isocyanate groups in an amount of 2.8-4.2%, divinyl rubber with hydroxyl end groups having the same diene chain microstructure and molecular a mass with a urethane prepolymer significantly increases the speed of curing of compositions without access to air moisture: their strength when cured without access of air is close to the strength when cured in air, and also increases the bond strength to mpozitsy materials conveyor belts based nonpolar uchukov Ka.

When polymers with terminal hydroxyl groups that do not have the same microstructure as the urethane resin prepolymer, namely PDI-1 rubber, laprol 503,1,4-butanediol are introduced into the composition, the strength of the compositions upon curing without air access is 2 times less than the strength of the compositions cured in air (Examples 8-9), as well as less bond strength with conveyor belt materials.

Claims (2)

1. A sealing composition comprising a divinyl rubber-based urethane prepolymer containing 2.8-4.2% isocyanate groups, carbon black and triethanolamine, characterized in that, in order to increase the cure speed of the sealant without access to moisture in normal temperature, along with an increase in tensile strength and bond strength with rubber based on non-polar rubbers, it additionally contains liquid divinyl rubber with terminal hydroxyl groups having the same microstructure for yen chain and molecular weight with a urethane prepolymer in the following ratio of components, parts by weight: Urethane prepolymer 100 Divinyl rubber 26.0-65.0 Triethanolamine 1.2-3.0 Carbon Black 7.5-22.0 2. The composition according to claim 1, characterized in that, in order to improve the quality of mixing, the urethane prepolymer contains titanium dioxide in an amount of 5-15 parts by weight. COMPOSITION OF COMPOSITIONS Table I urethane "orpolymer 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 SKU-DF-2 based on di-vinyl rubber containing 2, & -4,2Ј isocyanate groups Divinyugovy rubber with end gndronsilnymi groups OD-GTRA Polybutadiene rubber with terminal hydroxyl groups ODI-1 Polyester Laprol 503 1.4 butazdiol Triathanolamine 2.5 26.0 45.0 65.0 36.0 36.0 36.0 47.1 3.0 2.1 1.2 2.6 2.6 2.6 2.6 Carbon black P803 10.0 22.0 22.0 22.0 22.0 Titanium dioxide 7.0 11.0 22.0 5.0 10.0 7.9 2 1.4 2.6 22.0 22.0 Song Properties Characteristic Example indicator 1Sh1G1G1E11Sh1 E Pot life, min k $ 130 125 240 100 180 Cure time, day 3-5 22222 Conditional breaking strength, NPA 175 2 205 105 3 3 150 5 when cured in air 2.02.7 1.12.5 when cured without air Strength of bond with conveyor pent materials, kN / m: with outer lining rubber based non-polar rubbers 0.6 t, 7 with rubber fabric 2, 5 8.1 47.1 7.9 2 1.4 2.6 7.0 11.0 22.0 5.0 10.0 22.0 22.0 Table 205 105 3 3 150 5 8 3.2 0.9 1.8 3.9 t, 7 0.5 1.2, 5 2.1 1.3 2.0