RU2559469C1 - Complex age resistor for rubbers - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to obtaining complex age resistor for rubbers and can be used in tyre and rubber industry. Complex age resistor for rubbers includes, wt.p.: powder-like carrier-colloidal silicic acid - 45-55 and liquid alloy of age resistors - 45-55. Alloy of age resistors contains, wt.p.: N-isopropyl-N'-phenyl-n-phenylenediamine - 19.50-22.50, ε-caprolactam - 19.50-22.50, salicylic acid - 10.50-11.50, zinc oxide - 33.00-37.00.

EFFECT: invention makes it possible to increase thermoxidative resistance of rubbers for a long time period of their exploitation.

2 tbl, 2 ex

Description

The invention relates to the production of a comprehensive antioxidant for rubbers, which provides the latter with the best preservation of properties in the process of thermo-oxidative aging. The invention can be used in the tire and rubber industry to provide thermo-oxidative resistance to rubber for a long time of their operation.

Known antioxidant polymer 2,2,4-trimethyl 1,2-dihydroquinoline (RF Patent No. 20111663, IPC C08K 5/18, C08L 9/00 publ. 04/30/1994).

As a rule, obtaining this antioxidant is a complex process and is accompanied by the formation of a large amount of waste.

Known antioxidant N-isopropyl-N′-phenyl-n-phenylenediamine (Koshelev F.F. and other General technology of rubber, ed. "Chemistry", M., 1968, p.174).

The disadvantage of the antioxidant N-isopropyl-N′-phenyl-n-phenylenediamine is the short-term protection of the vulcanizates based on them from thermooxidative aging, since the antioxidant is characterized by unproductive consumption due to the high diffusion activity, which leads to evaporation and leaching from the surface of the vulcanizates (rubber and rubber, No. 2, 2001, p. 26-31).

Known composite antioxidant, which is introduced into the rubber compound [RF Patent No. 2236423, IPC C08L 7/00, C08L 9/00, C08L 9/02, C08K 13/02, C08K 13/02, C08K 3/22, C08K 3/26 , C08K 3/36, C08K 5/16, C08K 5.18, C08K 5/47 publ. 09/20/04] and consists of a powdered carrier - colloidal silicic acid and a liquid alloy of antioxidants obtained at a temperature of 70-90 ° C, containing N-isopropyl-N′-phenyl-n-phenylenediamine, ε-caprolactam, N, N′-diphenyl -n-phenylenediamine, 2-mercaptobenzthiazole in the following ratio, wt.h .:

N-isopropyl-N′-phenyl-n-phenylenediamine 35.00-40.00 N, N′-diphenyl-n-phenylenediamine 10.00-24.00 2-mercaptobenzthiazole 6.00-10.00 ε-caprolactam 35.00-40.00

and a powdered carrier, and the ratio of the alloy of antioxidants and powdered carrier is, wt.h .:

antioxidant alloy 15.00-50.00 powder carrier 50.00-85.00

However, the presence of 2-mercaptobenzthiazole in the composition of the composite antioxidant for rubbers leads to the appearance of a characteristic odor, which, as is known [Large Handbook of Rubber Worker, p.503], is inherent in the latter.

Known composite antioxidant, which is introduced into the rubber compound [RF Patent No. 2443730, MKI C08L 7/00, C08L 9/00, C08L 9/06, C08K 3/24, C08K 3/36, C08K 5/18, C08K 13/02 publ. May 27, 2002] and consists of a powdered carrier - colloidal silicic acid and a liquid alloy of antioxidants obtained at a temperature of 70-90 ° C, containing N-isopropyl-N′-phenyl-n-phenylenediamine, ε-caprolactam, stearic acid, boric acid in in the form of a preliminarily obtained alloy in ε-caprolactam at a temperature of 110-115 ° C with the following content of ingredients, parts by weight:

N-isopropyl-N′-phenyl-n-phenylenediamine 50.00-55.00 ε-caprolactam 20.00-22.00 stearic acid 5.00-6.50 boric acid 20.00-22.00

moreover, the ratio of the alloy of antioxidants and powder carrier is, wt.h .:

antioxidant alloy 55.00-60.00 colloidal silicic acid 40.00-45.00

However, in this case, the composite antioxidant does not provide a high level of protection against thermo-oxidative aging for a long time.

It is known [RF Patent for the invention 2279450, MKI C08K 13/02, C08K 5/18, C08K 5/20, C08K 9/04, C08L 21/00, publ. 07/10/2006] the use of a composite antioxidant for rubbers, consisting of a liquid alloy of antioxidants and a powdery carrier in a mass ratio of 50:50. The liquid alloy of antioxidants is a eutectic alloy of N-isopropyl-N′-phenyl-n-phenylenediamine and ε-caprolactam in a ratio of 60: 40% by weight, and the powdery carrier is natural sodium bentonite treated in an aqueous solution of isopropanol with surface-active substances . Composite antioxidant allows the rubber to provide a sufficiently high level of ozone resistance for a long time of their operation.

However, the disadvantage of the composite antioxidant is the need to treat the powdered carrier with surface-active substances, which complicates the technological scheme of its preparation and entails additional economic costs.

Closest to the claimed complex antioxidant is a composite antioxidant, which is introduced into the rubber compound [RF Patent No. 2355718, IPC C08L 7/00, C08L 9/00, C08L 9/06, C08K 5/18, C08K 13/02, publ. 05/20/09] and consists of a powdered carrier - colloidal silicic acid and a liquid alloy of antioxidants obtained at a temperature of 70-90 ° C, containing N-isopropyl-N′-phenyl-n-phenylenediamine, ε-caprolactam, polymer 2,2,4 -trimethyl-1,2-dihydroquinoline, stearic acid, boric acid in the form of a preliminarily obtained alloy in ε-caprolactam at a temperature of 110-115 ° C with the following ingredients, wt.h .:

N-Isopropyl-N′-phenyl-n-phenylenediamine 21.00-22.50 2,2,4-trimethyl-1,2-dihydroquinoline polymer 10.00-11.50 ε-caprolactam 11.00-14.00 stearic acid 10.00-11.50 protective wax 24.00-25.50

and the ratio of alloy and colloidal silicic acid is, wt.h .:

antioxidant alloy 76.00-84.00 colloidal silicic acid 16.00-24.00

However, in this case, rubber compounds containing a composite antioxidant cannot provide vulcanizates with a high level of aging protection due to the fact that in this case N-isopropyl-N′-phenyl-n-phenylenediamine and ε-caprolactam are not included in the ligand sphere of zinc oxide with the formation of a coordinated complex compound.

The problem to which this invention is directed is to obtain a comprehensive antioxidant for rubbers providing a high level of thermo-oxidative resistance to rubbers for a long time of their operation.

The technical result is to increase the thermal oxidative stability of the vulcanizates with the introduction of the proposed complex antioxidant.

The technical result is achieved in an integrated antioxidant for rubbers, consisting of a powdered carrier - colloidal silicic acid and a liquid alloy of antioxidants containing N-isopropyl-N′-phenyl-n-phenylenediamine, ε-caprolactam and acid, while the liquid alloy of antioxidants contains zinc oxide and as an acid - salicylic acid in the following ratio of ingredients, parts by weight:

N-isopropyl-N′-phenyl-n-phenylenediamine 19.50-22.50 ε-caprolactam 19.50-22.50 salicylic acid 10.50-11.50 zinc oxide 33.00-37.00

and the ratio of alloy and colloidal silicic acid is, wt.h .:

antioxidant alloy 45.00-55.00 powder carrier 55.00-45.00

When salicylic acid is introduced into the antioxidant, it interacts with zinc oxide dispersed in a molten mixture of N-isopropyl-N′-phenyl-n-phenylenediamine and ε-caprolactam to form zinc salicylate. Moreover, around zinc are coordinated [Kharitonov Yu.Ya., Tuyebakhova Z.K. Salicylate complexes of cobalt, nickel, zinc and cadmium, Coord. Chemistry, 1983, vol. 9, 16 II, pp. 1512-1527] neutral ε-caprolactam and N-isopropyl-N-phenyl-n-phenylenediamine molecules present in the alloy to form a coordinated complex compound.

The complex antioxidant for rubbers provides effective protection during thermooxidative aging due to the synergism of antioxidants - N-isopropyl-N′-phenyl-n-phenylenediamine and ε-caprolactam present in the ligand sphere of the complex antioxidant.

The following substances are used in the complex antioxidant: N-isopropyl-N′-phenyl-n-phenylenediamine TU 2492-002-05761637-99; ε-caprolactam GOST 7850-86; salicylic acid GOST 624-70; zinc oxide GOST 202-84; colloidal silicic acid GOST 18307-78.

When zinc oxide is added less than 33.00 parts by weight there is a decrease in the rate of vulcanization. Content of more than 37.00 parts by weight leads to a significant increase in the viscosity of the complex salt, which leads to technological difficulties when unloading the product from the reactor.

The use of the proposed method, the use of N-isopropyl-N′-phenide-n-phenylenediamine and ε-caprolactam less than 19.50 wt. including impractical, since the product has less efficiency in protecting against thermo-oxidative aging. When the content of N-isopropyl-N′-phenyl-n-phenylenediamine and ε-caprolactam is more than 24.50 wt. including the increase in the effectiveness of the complex antioxidant.

The content of ε-caprolactam in the complex antioxidant in the dosage range 19.50 - 24.50 wt. h. it is necessary, first of all, to create a dispersion medium with optimal viscosity, as well as N-isopropyl-N′-phenyl-n-phenylenediamine, for the formation of the ligand sphere of the complex compound.

The content of salicylic acid 10.50-11.50 wt. hours is also determined by the stoichiometric amount necessary for the formation of zinc salicylate, which, in turn, is necessary to create the conditions for obtaining a complex antioxidant as a whole.

Colloidal silicic acid, which, in fact, is a hard shell of capsules, is used as a powdered carrier. When using the proposed method, colloidal silicic acid is below 45.00 wt. including the effect of encapsulation is not achieved. A comprehensive antioxidant, in this case, takes a pasty form. When using colloidal silicic acid over 55.00 wt. including a decrease in the antioxidant content in the resulting composition, which adversely affects the prolonging ability of the substance.

Obtaining a complex antioxidant is carried out in a heated reactor equipped with a stirrer:

- at a temperature of 70-90 ° C, the calculated amount of ε-caprolactam and N-Isopropyl-N′-phenyl-n-phenylenediamine is loaded into the reactor. System components melt; form within 10-15 minutes with stirring a homogeneous alloy. Then, the calculated amount of zinc oxide is loaded into the alloy and, while stirring, homogenized for 20-25 minutes. The system temperature is increased to 110-115 ° C and salicylic acid is introduced in portions to form zinc salicylate (each portion is approximately 1/5 of the total calculated amount of salicylic acid). The time required for the complete conversion of the reagents and the preparation of the complex compound as a whole is 120-130 minutes with a total mass of components in the reactor of 300 g. The resulting product is a dark blue viscous liquid.

For comparison, control rubber mixtures were prepared for the manufacture of agricultural tire tread, containing an antioxidant polymer 2,2,4-trimethyl 1,2-dihydroquinoline (compositions 1, 2 in Tables 1, 2), an antioxidant N-isopropyl-N′-phenyl- n-phenylenediamine (compositions 3, 4 in Tables 1, 2), as well as a composite antioxidant (prototype) according to Example 1 described in RF patent No. 2355718. The compositions and properties of rubber compounds containing a composite antioxidant (prototype) are presented in tables 1 and 2. (compositions 5 and 6).

Known and proposed rubber compounds were prepared according to the standard mode: vulcanized in a press with electric heating at a temperature of 155 ° C in optimum.

In order to determine the optimal dosage of a complex antioxidant, uterine rubber mixtures were prepared, the composition of which is shown in Table 1, but with different contents of the inventive antioxidant.

Table 1. Composition of rubber compounds for the manufacture of agricultural tire treads (mixtures based on a combination of rubbers SKI-3, SKD-EF and SKMS-30 ARKM-15) Ingredients The composition of the rubber mixture per 100 parts by weight rubber one 2 3 four 5 6 7 8 9 10 Rubber SKI-3 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 Rubber SKD-EF 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 Rubber SKS-30 ARKM-15 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 TU N 550 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 White zinc BTsOM 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 Benzoic acid 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Styrene Linden Resin 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 Protective wax YaV-1 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 Resin Picard N-134 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 Stearic acid 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 Oil Norman 346 11.00 11.00 11.00 11.00 11.00 11.00 11.00 11.00 11.00 11.00 Ground sulfur 1.20 1.20 1.20 1.20 1.20 1.20 1.20 1.20 1.20 1.20 Santogard PVI 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20

Accelerator SBC 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 2,2,4-trimethyl 1,2-dihydroquinoline polymer (acetonanil H) 1.00 2.00 - - - - - - - - N-Isopropyl-N′-Phenyl-n-Phenylenediamine (IPPD) - - 1.00 2.00 - - - - - - Composite Antioxidant (prototype) - - - - 1.00 2.00 - - - - Complex antioxidant (example 1) - - - - - - 1.00 2.00 - - Complex antioxidant (example 2) - - - - - - - - 1.00 2.00

Table 2. Physico-mechanical properties of rubber compounds and vulcanizates, the composition of which is shown in table 1. Name of indicator Composition number one 2 3 four 5 6 7 8 9 10 Conditional tensile strength, MPa (GOST 270-75) 19.3 19.5 19.1 19.2 24.0 24.0 25.0 25.5 25.7 25.8 Conditional stress at 300% elongation, MPa (GOST 270-75) 6.1 6.2 5,6 7.0 3.6 3.6 9.3 10.7 9.3 8.5 Elongation at break,% (GOST 270-75) 560 580 550 590 550 550 560 570 560 580 Change in conditional tensile strength during thermo-oxidative aging (72 h × 100 ° C),% (GOST 9.024-74) -27 -25 -thirty -26 -26 -eighteen -12 -eleven -eleven -10 Change in elongation at break during thermo-oxidative aging (72 h × 100 ° C),% (GOST 9.024-74) -36 -40 -34 -32 -thirty -31 -25 -23 -22 -21

The following compounds were used as rubbers in rubber compounds: polyisoprene combinations GOST 14925-79, butadiene GOST 14924-75, styrene butadiene GOST 11138-78. Vulcanizing substances, accelerators are selected from the group: sulfur GOST 1271-93; sulfenamides TU 6-14-756-78; vulcanization activators: zinc oxide GOST 202-84. In addition, plasticizers (benzoic acid GOST 6413-77, styrene-lindenic resin TU 14-6-89-73, resin "Picard N" -134 TU 2451-010-54861661-2003, stearic acid GOST 6484- 96, Norman oil 346 ISO 9001: 2000), fillers (carbon black GOST 7885-86); antiozonants (wax YaV-1 TU 38-301-25-11-93); anti-scorchings (Santogard PVI GOST 7119-77); antioxidants (N-isopropyl-N′-phenyl-n-phenylenediamine GOST 14039-78; acetonanil N (GOST 19433-88-9153).

From the above table. 2 of the results of physical and mechanical tests of vulcanized rubber compounds, it follows that the proposed integrated antioxidant to a greater extent than the antioxidant of the prototype, protects the rubber from the action of heat and oxygen. It should be noted that its presence in the rubber compound also contributes to an increase in the conditional tensile strength and stresses at specified elongations while maintaining the relative elongation inherent in control vulcanizates at an optimal level. The results give grounds for the replacement of acetonanil H and IPPD with the claimed complex antioxidant.

Example 1. The alloy is carried out in a heated reactor equipped with a stirrer:

- at a temperature of 70-90 ° C, 19.50 g of ε-caprolactam and 19.50 g of N-isopropyl-N′-phenyl-n-phenylenediamine are charged into a 0.50 L porcelain reactor. System components melt; form within 10-15 minutes with stirring a homogeneous alloy. Then, 33.00 g of zinc oxide is loaded into the alloy and, while stirring, homogenized for 20-25 minutes. Raise the system temperature to 110-115 ° C and inject salicylic acid in portions to form zinc salicylate [each portion is approximately 1/5 of the total estimated amount of salicylic acid (10.50 g)]. The time required for the complete conversion of the reagents and the preparation of the complex compound as a whole is 120 minutes.

In 45 g of the obtained alloy, 55 g of colloidal silicic acid are charged, mixed, and then transferred to a ball mill for encapsulation. Unloading of the product is carried out after 45-60 minutes in a receiving tank.

The protective actions of the inventive integrated antioxidant against the effects of heat and oxygen on rubber were evaluated in an object represented by a vulcanized rubber compound for the manufacture of a running part of a tire tread. The compositions and properties of rubber compounds and their vulcanizates containing a complex antioxidant prepared according to example 1 are shown in table. 1 and table 2 (compounds 7, 8).

Example 2. The preparation of a complex antioxidant was carried out analogously to example 1 and was characterized in that the quantitative content of the components in the alloy was, g .; 22.50 - N-isopropyl-N′-phenyl-n-phenylenediamine; 22.50 - ε-caprolactam; 37 - zinc oxide; 11.50 - salicylic acid. Into 55 g of the obtained alloy, 45 g of colloidal silicic acid were charged, mixed, and then transferred to a ball mill for encapsulation. Unloading of the product is carried out after 45-60 minutes in a receiving tank.

The protective actions of the inventive complex antioxidant against the effects of heat and oxygen on rubber were evaluated in the object specified in example 1. The compositions and properties of rubber compounds and their vulcanizates containing a complex antioxidant prepared according to example 2 are shown in table. 1 and table 2 (compositions 9, 10).

Thus, the use of the proposed integrated antioxidant provides a higher level of thermal oxidative resistance to rubbers in comparison with antioxidants of the control mixture and antioxidants of the rubber mixture of the prototype.

Claims (1)

Comprehensive antioxidant for rubbers, consisting of a powdered carrier - colloidal silicic acid and a liquid alloy of antioxidants containing N-isopropyl-N′-phenyl-n-phenylenediamine, ε-caprolactam and acid, characterized in that the liquid alloy of antioxidants contains zinc oxide, and in the quality of the acid is salicylic acid in the following ratio of ingredients, parts by weight:
N-isopropyl-N′-phenyl-n-phenylenediamine 19.50-22.50 ε-caprolactam 19.50-22.50 salicylic acid 10.50-11.50 zinc oxide 33.00-37.00
and the ratio of alloy and colloidal silicic acid is, wt.h .:
antioxidant alloy 45-55 powder carrier 45-55