CS267387B1 - Adhesive agent - Google Patents

Abstract

The present invention relates to the use of Ο, Ο-dialkyl phosphates of copper (I) in which the alkyl groups are the same or different and represent C4 to C18 alkyl or cyclohexyl as the adhesive agent to increase the adhesion of the rubber to the reinforcing materials, in particular to the steel cord. . It can be used in the chemical industry.

Description

The invention relates to the use of O, O-dialkyl copper phosphates as an adhesive for increasing the adhesion of rubber to reinforcing materials, in particular to steel cord.

The development of the production and use of tires and other rubber products reinforced with steel cord is arousing increased interest in the adhesive properties of steel cord. To improve the adhesive properties, the steel cord is helped. soot. According to previous knowledge, the adhesion between the brass layer and the rubber occurs as a result of the formation of a thin film of sulfide, a medium on the surface in the initial stage of vulcanization. This film has good adhesive and cohesive properties and, in addition, is porous, so that the molecules of the vulcanizing rubber penetrate into it. However, the action of water, oxygen, sodium chloride and other agents leads to corrosion of the brassed steel cord (and galvanized steel rope in the case of conveyor belts) and thus reduces the adhesion of the rubber-steel cord system, which negatively affects the life of the product. For these reasons, the adhesion of the brassier himself, resp. galvanized steel cord to rubber is insufficient.

To improve the adhesion of the treated cord, various adhesives are added to the applied steel cord rubber compounds, which increase the adhesion of the rubber-steel cord system, improve the corrosion resistance of the steel cord, and prevent the adhesion from being destroyed. The result of such interventions is an increased service life of the products. Phenol formaldehyde resins (U.S. Pat. No. 4,236,564), cresol formaldehyde resins, resorcinol formaldehyde condensates, triazine derivatives (GB 1 575 516) and in particular transition metal compounds from the group of inorganic salts (EP 26 294), organic acid salts (U.S. Pat. No. 4,340) are used as adhesives. 515) and complex compounds, especially cobalt and nickel (US 4,137,359). An organometallic adhesive based on a compound of cobalt and boron of the general formula has found a significant practical application:

B (O-Co-X) ₃ where X is a monocarboxylic acid residue containing 7 to 11 C atoms (DE 2 921 289), * which is much more efficient compared to simple cobalt compounds and ensures good adhesion of different types of vulcanized rubbers to the steel cord .

In practice, combined adhesive systems are also used, which most often consist of the already mentioned organic cobalt compounds and the so-called RHS system consisting of resorcinol (R), hexamethylenetetramine (H) and precipitated creic acid (S). During vulcanization, the resorcinol is reacted with hexamethylenetetramine (or another methylene group donor, e.g., hexamethoxymethylmelamine) to form a resorcinol formaldehyde resin (U.S. Pat. No. 4,057,529). In the literature (Nichols M.]., Ohm R. F. - Adhesives Age 19, No. 7, 25-30, (1976), beta-naphthol is mentioned as a possible replacement for resor.

CS 267 387 B1 tin in the RHS system in the role of acceptor of the methylene group, resp. formaldehyde, which is formed by the reaction of hexamethylenetetramine with water at elevated temperatures.

A significant disadvantage of said adhesive systems is, in the first place, the high prices of cobalt compounds. When used in the increased doses required to achieve the desired degree of adhesion, the resistance of the vulcanizate to thermal aging deteriorates and they "bloom" on the surface of the rubber compound, thereby reducing the so-called ready-made tack of the mixture. The disadvantages of resorcinol lie mainly in its unfavorable hygienic-toxicological properties (irritating to the skin, eyes, causes dermatosis), insufficient dispersion in the rubber mixture and the fact that it is a deficient raw material.

It has now been found that the adhesion of rubber to reinforcing materials, in particular to steel cord, is significantly increased by β, β-dialkylphosphates of the general formula I

Cu (I) wherein R ¹ and R ² are the same or different and represent linear or branched C ₄ to C ₈ alkyl or cyclohexyl.

Said compounds are known, but their ability to increase the adhesion of rubber to reinforcing materials has not yet been identified and described. In order to achieve an increased adhesion of the rubber to the reinforcing materials, at least one compound of the formula I is added to the rubber mixture in an amount of 1 to 4 parts by weight, parts per 100 parts by weight of rubber, optionally together with the so-called RHS adhesive system. The compounds of the formula I according to the invention can be used in the production of rubber products reinforced in particular with steel cord, from both natural and synthetic rubbers.

The β, β-copper dialkyl phosphates of the formula I according to the invention are well incorporated into rubber compounds and are compatible with other rubber additives used in practice, such as accelerators, vulcanizing agents, wetting agents, fillers, antidegradants, etc. Their advantage over known adhesives is, among other things, that they provide a high degree of adhesion of the rubber-steel cord system at substantially lower costs, while significantly reducing the corrosion of the steel cord and thus the decrease in adhesion, which results in longer product life.

The following example illustrates but does not limit the scope of the invention.

CS 267 387 Bl

Example

A rubber premix of the following composition was used in the experiments:

Ingredients mass diet natural rubber100 stearic acid1.5 zinc oxide10 carbon black, type N-33065 plasticizer2

N-isopropyl-N'-phenyl-p-phenylenediamine1 phenyl-white-naphthylamine1

180.5

The vulcanization system and the tested adhesives were mixed into said premix according to the following schedule:

cd

ABOUT

N

CS 267 387 Bl

After determining the vulcanization characteristics of the mixture on a Monsanto Rheometer at 145 ° C, test specimens were prepared by vulcanization at 145 ° C. The adhesion of the vulcanizates to the brass-plated steel cord x 4 x 0.22 mm and 1 x 0.15 mm was metallized according to ON 62 1465. The principle of the method is that the force required to pull out the cord pressed into the rubber test piece in depth 25 mm. The degree of covering of the torn part of the cord with rubber was also monitored, which complements the picture of the character of the joint defect.

The resistance of the cohesiveness of the vulcanizate and the cord to the influences occurring when using rubber products reinforced with a steel cord was tested under the following conditions:

a) test piece with pressed cords, immersed in 10% sodium chloride solution for 24 h at 20 ° C,

b) a test piece exposed for 24 hours to a temperature of 80 ° C and a relative humidity of 95%,

c) thermal stress of the test specimen for days at 100 ° C,

d) 1 Repeated 45% compression deformation of the test specimen.

The measured values are summarized in the following table.

about 4.6 17.2 24.9 O Cd m Os so m m 1170 o in in o in OO OS r— < 06 ο Ο Ο Ο γ- r- in oo r- SO cd about. m scT O ABOUT © o in © © © ο ιη os C4 about SQ Sat 00 sO about Γ- Γ- SO m δ what The person SO 00 4.4 16.9 in n) o co co 16.5 145 1180 o o O ΓΟΟ r- © Os so 009 Φ Os ιη ο ο © so so m cd _r so Tt f-— m ABOUT so © ABOUT o o so oo m Os © in oo in in © © ο so m m T — í SO SO m δ cT Oy Os about sO O about in o ABOUT »N • n in o in o <D E SO «-Η ? i t- <iS 120 OO Os OS r- about © SO Os r- r- <n N ABOUT ABOUT r-f in in oq so »n ABOUT in m about © in m> n © © no LT) cd Cd SO The SO © oo so so tn in m sO ^ c_j ¹ Os cc m Cd Cl δ o w m About Od »N in in os <n Os o m in Os m o »n in so so in’ rt cd what r- oo sO Cl v — 1 cd m 3.6 L6.0 23.5 about o and o ABOUT o o so cn © 90 © oo © o o © Tt in in rJ X m v— < oš in r- SO • η Λ H WHAT m 00 Cd in 15, 24, Cd 14. 125 1140 δ δ in oo so 600 δ in * n o © co in in in Os v — 1 - in 15,. 24, T— < CO O 860 in o in os so with 510 in m Q © Cd O1 _tí δ 4U CZ> <Λ Q c o> o 3 & 52 J2> vulcanizái 45 ° C) (MPa in , (MP tnm) sucking dmienkac! surface %) υ Λ R ^ c o E Ό řť £ and time -mech ^ c90 ’1 ulkani What's up those 5 days ago ^z °) (N / 251 after pouring in po my cover ( I force ABOUT a rt £ υ Ό 4— » Vulcanization Process timin ') optimal t _c90 (min) Physical properties strength in tn O C C3 to age ¹ 90 ° C: tensile strength (' Adhesion, 24 hours after aging © 9 i * ³ Λ 5 S. ^ 5 «ao i- ο 44 Q- Λ

CS 267 387 Bl

Claims (1)

OBJECT OF THE INVENTION The use of Ο, Ο-dialkylphosphates of the general formula wherein R 1 and R 2 are the same or different and denote linear or branched C 4 -C 18 alkyl or cyclohexyl as the adhesive agent to enhance the adhesion of the rubber to the reinforcing material especially the steel cord. Cu (I)