RU2271374C1 - Polyurethane composition for manufacturing articles - Google Patents

Abstract

FIELD: polymer materials.

SUBSTANCE: invention relates to polyurethane elastomers suited to manufacture polyurethane articles. Composition according to invention contains (i) 70.6-74.8% polyfurite urethane prepolymer prepared by reaction between 2.1 mile 2,4-tolylenediisocyanate and 1.0 mole poly(oxytetramethylene glycol) with molecular weight 1500 and (ii) liquid curing agent (to 100%), which is a mixture of 3,3'-dichloro-4,4'-diaminodiphenylmethane and poly(oxytetramethylene glycol) with molecular weight 1000 at their molar ratio 1:1. Thus obtained polyurethane elastomers show Shore hardness al a level of 93 relative units, breaking point (23°C) at a level of 38 MPa, elongation on fracture 712%, and abrasion resistance 27 mcm (according to Russian standard GOST 11529-86). Articles manufactured from these elastomers may find use for in-tube flaw inspection of oil and gas mains as well as oil storage tanks.

EFFECT: enlarged assortment of industrially useful elastomers.

4 tbl, 6 ex

Description

The invention relates to compositions of polyurethane elastomers intended for the manufacture of polyurethane products (cuffs, sensor carriers and discs for cleaning scrapers) used in the oil and gas industries, for example, in-line inspection of main oil and gas pipelines and oil storage tanks.

Currently, for the manufacture of a wide range of products, the classic polyurethane composition based on a polyfurite prepolymer cured by aromatic amine 3,3'-dichloro-4,4'-diaminodiphenylmethane in the form of its melt in polyoxytetramethylene glycol with a molecular weight of 1000 is most often used. (US Patent No. 3718624, MKI ³ C 08 G 18/32. Liquid hardener for polyurethane systems.)

The use of a diamine hardener in the form of a solution in a non-volatile solvent made it possible, on the one hand, to increase the viability of the known polyurethane composition (time from mixing the prepolymer with the hardener to a viscosity level of 200-300 Pa · s, above which the reaction mass becomes non-technological and unsuitable for processing into products on existing equipment), but, on the other hand, led to a significant decrease in the deformation characteristics of the materials obtained and the hardness of elastomers by 8 ... 10 conventional units c according to Shore A, which is undesirable for products requiring high hardness.

Known injection polyurethane composition intended for the manufacture of large-sized elastic products (Patent RU No. 2155781, IPC C 08 L 75/04 from 10/07/1998, Polyurethane composition).

The composition contains, wt.%:

Polyurethane urethane prepolymer SKU-PFL-100 56.4-62.2 Urethane prepolymer based on 2.2 mol 2.4- toluene diisocyanate and 1.0 mole of oligooxyethylene glycol 8.6-13.4 with a molecular weight of 400 (prepolymer 402F) Liquid hardener based on 3,3'-Dichloro-4,4'- diaminodiphenylmethane (Diamet X) and polyoxytetramethylene glycol at their molar Rest

0.67: 0.33 ratio

This composition is accepted by the authors as a prototype.

The specified composition provides increased viability of the reaction mass (50 min or more at 60 ° C) and a high level of hardness (86-90 conventional units according to Shore A), as well as a set of other physical, mechanical and operational characteristics of the finished polyurethane materials in the products ( tensile strength 35.8 MPa, relative deformation at break 490%).

However, due to the high temperature of mechanical glass transition in the region of negative temperatures, such a composition loses its elastic properties and cannot be used (the glass transition temperature of the elastomer is -35 ° C). In addition, the high level of the module (conditional stress at 100% tension) prevents the use of the composition as the material of the actuator of various control devices. For example, gas line pressure regulators require the use of cuffs with a material module in the range of 2.5-5 MPa. Especially important is the low temperature dependence of the module, which determines the failure-free operation of the product in a wide temperature range of operation.

The technical problem solved in the framework of the present invention is to increase the viability of the reaction mass and abrasion resistance while providing high hardness and a relatively small modulus of elasticity, as well as expanding the temperature range of operation of the obtained products, i.e. increase frost resistance of the material.

The solution to the above problem is achieved due to the fact that the polyurethane composition for the manufacture of products containing a polyfurite urethane prepolymer and a liquid hardener, which is a mixture of 3,3'-dichloro-4,4'-diaminodiphenylmethane and polyoxytetramethylene glycol with a molar mass of 1000, as polyfuritic urethane prepolymer contains a prepolymer obtained by the interaction of 2.1 mol of 2,4-toluene diisocyanate and 1.0 mol of polyoxytetramethylene glycol with a mol. mass of 1500, the molar ratio of 3,3'-dichloro-4,4'-diaminophenylmethane and polyoxytetramethylene glycol is 0.5: 0.5, in the following ratio, wt.%:

Specified polyfuritic urethane prepolymer 70.6-74.8 Specified Liquid Hardener Rest

In the composition of the claimed polyurethane composition, a polyfuritic urethane prepolymer is used, which is the product of the interaction of 2.1 moles of 2,4-toluene diisocyanate (product 102T) (TU 113-38-95-90) and 1.0 mol of polyoxytetramethylene glycol (polyfurite) with a mol. mass of 1500 (TU 6-02-646-81).

A hardener based on aromatic diamine 3,3'-dichloro-4,4'-diaminodiphenylmethane (Diamet X) (TU 6-14-980-84) and polyoxytetramethylene glycol with a molar mass of 1000 (TU 6-02- 646-81) with a molar ratio of 0.5: 0.5.

The manufacturing process of the polyurethane composition consists of the following operations:

- synthesis of a prepolymer based on 2,4-toluene diisocyanate and polyoxytetramethylene glycol with a molecular weight of 1500;

- preparation of a liquid hardener;

- preparation of a polyurethane composition and pouring it into molds;

- polymerization of products.

The prepolymer is synthesized in a synthesis reactor at a temperature of (60-70) ° С at a vacuum pressure minus 0.09 MPa and a working stirrer.

After preparation of the prepolymer, cold water is introduced into the reactor jacket to lower the temperature of the prepolymer to (25-30) ° C and stirring is performed.

The liquid hardener is prepared in a container with heating with constant stirring, while polyfurite with a mol. Heated to (40-45) ° C. weighing 1000 at atmospheric pressure, a portion of Dia X is loaded.

Mixing the prepolymer and liquid hardener is carried out at a temperature of (40-50) ° C, after which the reaction mass at a temperature of (115-125) ° C is poured into molds for curing. Optimally selected polymerization mode: 3 hours at 115 ° C and 16-18 hours at 80-90 ° C.

The novelty and inventive step of the invention lies in the fact that polyurethanes of different molecular weights are present in the polyurethane composition, which made it possible to obtain a low-modulus material with high hardness and resistance.

The claimed limits of the ratios between the components are determined experimentally and are optimal from the point of view of the formation of the structure of the polyurethane matrix, which ensures the achievement of a high complex of physico-mechanical characteristics of the finished material.

Physico-mechanical characteristics are determined after polymerization at a temperature of (115 ± 5) ° C for 3 hours, followed by polymerization at a temperature of (80 ± 5) ° C for 18-21 hours.

The viability of the reaction mass was evaluated according to the results of a study of its rheological characteristics on a Reotest-2 device at a temperature of 25 ° C.

The glass transition temperature of the elastomer was determined on a DSM-2 differential scanning calorimeter under conditions of slow heating of samples at a rate of 0.02 deg / s.

Strength characteristics were determined according to GOST 270-75.

Abrasion resistance according to GOST 11529-86.

The technical nature of the invention is illustrated by the following experimental data.

Table 1 shows the formulations of polyurethane compositions according to examples of specific performance, and table 2 shows the comparative characteristics of the reaction mixtures and polyurethane elastomers obtained on their basis.

From tables 1 and 2 it is seen that the hardness of polyurethane elastomers is more than 80 conventional units Shore A and a relatively low modulus is achieved in cases where the ratio between the components is within the claimed limits.

The composition of the liquid hardener and its effect on the change in the viability of polyurethane compositions and the physicomechanical properties of the elastomers obtained from them are given in Tables 3 and 4, from which it can be seen that the change in the molar ratio between Diamett X and polyfurite in one direction or another from the optimal (0 , 5 / 0.5) adversely affects the complex of physico-mechanical properties of elastomers and the viability of the reaction mass.

Thus, the inventive polyurethane composition based on a polyfurite prepolymer allows, while maintaining a high level of most physical and mechanical properties (tensile strength, relative deformation at break), to provide a low-modulus elastomer with a sufficiently high hardness, abrasion resistance, and a more viable reaction mass 180 minutes.

Table 1 Composition components Content in composition,% (mole fraction) 1 (prototype) Case Studies 2 3 four 5 6 Prepolymer SKU-PFL-100 56.4-62.2 (0.7-0.8) - - - - - Prepolymer 402F 13.4-11.0 (0.2-0.3) - - - - - A prepolymer based on 2.1 moles of 2,4-toluene diisocyanate and 1 mole of polyoxytetramethylene glycol with a molar mass of 1500 - 68.5 (1.0) 70.6 (1.0) 72.7 (1.0) 74.8 (1.0) 76.9 (1.0) Liquid hardener: polyoxytetramethylene glycol with a molar mass of 1000 19.0-19.6 (0.33) 24.1 (0.5) 22.8 (0.5) 21.5 (0.5) 20.2 (0.5) 18.9 (0.5) 3,3'-dichloro-4,4'-diaminophenylmethane 10.2-10.6 (0.67) 7.4 (0.5) 6.6 (0.5) 5.8 (0.5) 5.0 (0.5) 4.2 (0.5)

table 2 Viability of reaction mixtures and physicomechanical properties of elastomers The compositions of table 1, for examples one 2 3 four 5 6 The viability of the reaction mixtures, min, at a temperature of 25 ° C 160 - 150 180 160 - Shore A hardness, arb. (GOST 263) 93 84 86 88 90 82 Tensile strength at break at a temperature of (23 ± 2) ° С, MPa 35.8 32,0 32,4 35,4 38,0 28.3 Elongation at break,% 490 670 690 712 690 578 Abrasion resistance, microns GOST 11529-86 fourteen - 22 27 22 - Conditional stress at 100% elongation, MPa 4.2 3.0 3.2 2.6 2.6 2,4 Mechanical glass transition temperature, ° С -35 -40 -40 -42 -40 -40

Table 4 Viability of reaction mixtures and physicomechanical properties of elastomers The compositions of table 3, for examples one 2 3 The viability of the reaction mixtures, min, at a temperature of 60 ° C 135 160 110 Tensile strength at break and temperature (23 ± 2), ° С 35,4 32.6 33,4 Elongation at break,% 712 762 615 Shore A hardness, arb. 90 88 86 Conditional stress at 100% elongation, MPa 3.2 2.7 2.6

Claims (1)

A polyurethane composition for the manufacture of articles containing a polyfuritic urethane prepolymer and a liquid hardener, which is a mixture of 3,3'-dichloro-4,4'-diaminodiphenylmethane and polyoxytetramethylene glycol with a molecular weight of 1000, characterized in that the composition contains a prepolymer of urethane prepolymer and prepolymer obtained by the interaction of 2.1 mol of 2,4-toluene diisocyanate and 1.0 mol of polyoxytetramethylene glycol with a molecular weight of 1500, the molar ratio of 3,3'-dichloro-4,4'-diaminodiphenylmethane and polyoxytetrameth ilenglycol is 0.5: 0.5, in the following ratio of components, wt.%: Specified polyfuritic urethane prepolymer 70.6-74.8 Specified Liquid Hardener Rest