GB1575516A

GB1575516A - Chloro-s-triazine/hexamethylenetetramine reaction products and their use in bonding rubber to copper or polyester

Info

Publication number: GB1575516A
Application number: GB2106276A
Authority: GB
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1977-05-09
Filing date: 1977-05-09
Publication date: 1980-09-24

Description

(54) CHLORO-S TRIAZINE-HEXAMETHYLENETETRAMINE REACTION PRODUCTS AND THEIR USE IN BONDING RUBBER TO COPPER OR POLYESTER (71) We, IMPERIAL CHEMICAL INDUSTRIES LIMITED, Imperial Chemical House, Millbank, London, SW1P 3JF, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to new triazine compounds and is more particularly concerned with reaction products of chloro-s-triazines and hexamethylene tetramine and the use of these compounds for improving the bond strength between rubber and either copper and its alloys such as brass, or polyester cords.

Composite articles in which rubber is bonded to these materials are useful for many purposes. For example tyres, hoses and belts of rubber are frequently reinforced with brasscoated steel cord. It is customary in this case to use additives in the rubber which improve the strength of the bond, but such additives, examples of which are formaldehyde generators in the presence of resorcinol, can cause undesirable effects such as a decrease in the scorch safety of the mix, alteration of cure rate, and fuming at high temepratures. Furthermore these additives may lead to skin irritation. The present invention relates to additives which can be used alone in the rubber when bonding to copper, which are much less prone to give objectionable fumes and which provide a considerable increase in bond strength.

A further property of these additives is found in connection with the bonding of rubber to polyester, e.g. polyethylene terephthalate, cords. In this case, it is usual to dip the cord into a rubber latex containing a resorcinol/formaldehyde condensation product, and usually a further additive, e.g. the condensation products of resorcinol, monohydric phenols and formaldehyde described in U.K. Patent Specification No. 1140528, and bake the treated cord for a few seconds at temperatures of e.g. 2200C or above before bringing the cord into contact with the vulcanizable rubber mix. If lower temperatures are used for the baking step, it is found that lower bond strengths are obtained between the rubber and the cord after vulcanisation. It has now been found, however, that by introducing the new additives into the rubber mix, that a lowering of the temperature of the baking step has much less effect on the final bond strength achieved.

Thus, according to one feature of the present invention there are provided s-triazine compounds of the general formula: [Triazine-(Cl),.,] (HMT)n (1) wherein m = 1, 2 or 3, Triazine (Cl)m is a s-triazine compound having m atoms of chlorine and represented by the general formula:

wherein Y and Z are the same or different and each represents Cl or an optionally substituted hydroxyl, amino or mercapto group, HMT Is hexamethylene tetramine and n is an integer less than or equal to me.

As examples of substituents on the hydroxyl, amino or mercapto groups, there may be mentioned alkyl groups of 1 to 12 carbon atoms, cycloalkyl, alkenyl of 3 to 12 carbon atoms, phenyl, optionally substituted by Cl, NO2, OH, C14 alkyl or C14 alkoxy, naphthyl, or in the case of amino, the substituent can take the form of a divalent radical making up a 5- or 6-membered heterocyclic ring with the nitrogen atom.

As particular examples of these, there may be mentioned methyl, ethyl, isopropyl, secbutyl, t-butyl, n-hexyl, t-octyl, n-dodecyl, cyclohexyl, allyl, but-2-enyl, 2-, 3- and 4chlorophenyl, 3,4-dichlorophenyl, 2-, 3- and 4-methylphenyl, 2-, 3- and 4-methoxyphenyl, 2-, 3- and 4-hydroxyphenyl, 4-t-butylphenyl, 2-chloro-4-methylphenyl and, as divalent radicals making up a heterocyclic ring, (CH2)4, (CH2)5, C2H4.N(CH3)C2H4 and C2H4OC2H4.

As examples of triazine compounds of formula (2) there may be mentioned: cyanuric chloride 2-amino-4,6-dichloro-s-triazine 2-methylamino-4,6-dichloro-s-triazine 2-dimethylamino-4,6-dichloro-s-triazine 2-dimethylamino-4-hydroxy-6-chloro-s- triazine 2-anilino-4,6-dichloro-s-triazine 2-N-methylanilino-4,6-dichloro -s-triazine 2,4-dianilino-6-chloro-s-triazine 2,4-diphenoxy-6-chloro-s-triazine 2-amino -4 -hydroxy-6-chloro-s-triazine 2-phenoxy-4-dimethylamino-6-chloro-s- triazine 2,4-diamino-6-chloro-s-triazine 2-phenoxy-4-amino-6-chloro-s-triazine 2-methoxy-4,6-dichloro-s-triazine 2-phenaxy-4-methylamino- 6-chloro-s- triazine 2,4-dimethoxy-6-chloro-s-triazine 2-phenoxy-4-N-methylanilino-6-chloro- s-triazine 2,4-di-n-butoxy-6-chloro -s -triazine 2,4-di-o-cresoxy-6-chloro-s-triazine 2,4-di- ( 2,6-xylenoxy-6-chloro-s-triazine 2-amino-4- ( m - hydroxyphenoxy-6-chloro s-triazine 2,4-di-(o-chlorophenoxy)-6-chloro-s- triazine 2-methylamino-4- (o-hydroxyphenyl) -6 chloro-s-triazine, and 2,4-di- (,B-naphthoxy) -6-chloro-s -triazine.

The invention also provides a process for manufacture of the new compounds which comprises reacting a triazine compound of formula (2) above with n molecular propor tions of hexamethylene tetramine.

The process can conveniently be carried out by stirring a mixture of the reactants in a suitable organic solvent or mixture of solvents, if necessary at an elevated temperature which may be, e.g. up to 1000C.

As organic solvents which may be used, it is preferred to use one in which hexamethylene tetramine is soluble at the reaction temperature to at least 10 g/l, e.g. chloroform, acetone.

Water may also be used as a solvent, preferably as a component of a solvent mixture.

In many cases, the reaction product precipitates during the course or at the end of the reaction, and can be isolated as a solid product by filtration, washing and drying. In other cases, the reaction product stays in solution, but can be obtained as a solid product by evaporation of the organic solvent. The products can be shown to be reaction products, since treatment with solvents such as acetone or .water extract only traces of starting materials.

Mixtures of the new triazine compounds can be obtained by reacting the triazine compound of formula (2) with a non-integral number of molecular proportions of hexamethylene tetramine.

The invention also provides a method of bonding a rubber to copper or an alloy thereof which comprises adding to a vulcanisable rubber composition at least one triazine compound of formula (1) above, bringing the vulcanizable rubber composition into contact with the copper or alloy thereof, and heating the composite article to vulcanise the rubber.

The rubber may be natural rubber or a vulcanisable synthetic rubber such as polymers including cis-polymers of butadiene and isoprene, polychlorobutadiene, and copolymers of dienes such as butadiene and isoprene with polymerisable compounds such as styrene, isobutene, acrylonitrile, and methyl methacrylate and terpolymers such as ethylene/ propylene/diolefin, and blends of these rubbers.

The invention is of particular value in promoting bonding of rubber to brass-coated steel cords since these are used to reinforce tyres and without a bonding agent they do not adhere adequately to the rubber. The invention is however also of use in promoting bonding to other copper articles and articles of copper alloys such as engine mountings, shock absorbers, chemical plant linings and metal reinforced bases.

The triazine compounds should be used in amount at least 0.1% and preferably between 1 and 5% of the weight of rubber. It is not necessary that the triazine compound should be distributed throughout the rubber, but only that it should be present in adequate amount in the region of the rubber/metal interface.

Thus comparatively small amounts of a rubber containing the triazine compound may be used as a bonding agent at the point of contact between metal and a rubber free from triazine compound.

Vulcanization may be carried out by heating the composite article to a temperature conventionally used for vulcanising the vul canisable rubber composite concerned. The vulcanisable rubber composition will normally contain a vulcanising agent such as sulphur or a sulphur donor for example N,N' - dithiobis - (hexahydro - 1H - azepinone - 2), bis (morpholino)disulphide or bis - (diethylthiophosphoryl)trisulphide and a vulcanisation accelerator for example benzothiazylsulphenamides such as benzothiazyl - 2 - cyclohexylsulphenamide, 2 - (morpholinothio) - benzothiazole, benzothiazyl - 2 - di - cyclohexylsulphenamide, and N - t - butyl - 2 - benzothiazolesulphenamide, 2 - mercaptobenzothiazole, bis - (2 - benzothiazyl) - disulphide, diarylguanidines, thiurams and dithiocarbamates.

The vulcanisable rubber composition may if desired contain other conventional rubber adjuvants such as antioxidants, antiozonants, fillers, reinforcing agents, pigments, processing oils and accelerator activators such as zinc oxide and stearic acid and also ingredients used in other bonding systems such as formaldehyde generators.

The triazine compounds other than cyanuric chloride may be prepared by any of the well-known conventional methods for replacing the chlorine atoms in cyanuric chloride with one or two of the groups Y and Z. For example cyanuric chloride may be reacted in any order with the required molar proportions of a compound Y.H., and if necessary, compound Z.H in presence of an acid binding agent at progressively higher temperatures.

According to yet a further feature of the invention, there is provided a process for bonding rubber to shaped polyester bodies which comprises immersing the polyester in a vulcanisable rubber latex containing resorcinol and formaldehyde or formaldehyde generator and/or reaction products thereof, baking the coated polyester, contacting the resultant coated polyester with a vulcanisable rubber composition containing one or more s-triazine compounds of formula (1) above and heating the composite article to vulcanise the rubber. The vulcanisable rubber latex can contain other conventional additives used in the polyester/rubber bonding art, e.g. the bonding agents described and claimed in Specification No. 1140528. The vulcanisabl rubber composition can be made up and vulcanised in a similar manner to that described above in connection with bonding to copper.

The advantage of the use of the s-triazine compounds of the invention in this process lies in the ability to use lower baking temperatures for coating the polyester fibre, without unacceptable loss of adhesion.

The invention is illustrated but not limited by the following Examples in which all parts and percentages are by weight unless otherwise stated.

Example 1.

A solution of 2 - anilino - 4,6 - dichloros - triazine (32.1 parts) in chloroform (600 parts) was added portionwise over 30 minutes to a solution of hexamethylene tetramine (37.4 parts) in chloroform (600 parts) at 20"C, and the reaction mixture was stirred at 30 35"C for 2 hours. Chloroform (800 parts) was removed on a rotary evaporator at 250C/ 12mm. Hg. and the residue was treated with petroleum ether 6080 (1000 parts). The solid product was filtered off and dried in a vacuum oven at 250C/12 mm. Hg. to constant weight. The product (69.4 parts) was obtained as a white powder.

Example 2.

A solution of cyanuric chloride (18.45 parts) in acetone (75 parts) was added over 30 minutes to a solution of hexamethylene tetramine (42 parts) in water (450 parts) at 5"C, and the reaction mixture was stirred at 5 C for 2 hours. The solid product which had precipitated was filtered off and dried in a vacuum desiccator over calcium dichloride at 200C/12 mm. Hg. The product analysed as C = 34.60/c, H = 3.9%, Cl = 23.1%, N = 32.2%. (C1 H2Cl3N1l requires C = 38.750/c, H = 5.17%, Cl = 22.93%, N = 33.15%).

Example 3.

A solution of 2 - amino - 4, 6- dichloros - triazine (16.5 parts) in dry acetone (350 parts) was added over 30 minutes to a solution of hexamethylene tetramine (14 parts) in dry chloroform (225 parts) at 200C and the reaction mixture was stirred at 20-250C for 2 hours. The solid product which had precipitated was filtered off and dried in a vacuum oven at 250C/12 mm. Hg. to constant weight. The product (28.2 parts) was obtained as a white solid.

Example 4.

A solution of cyanuric chloride (18.45 parts in chloroform (300 parts) was added portionwise over 15 minutes to a solution of hexamethylene tetramine (28 parts) in chloroform (440 parts) at 2v25 C, and the reaction mixture was stirred at 20--2S"C for 2 hours.

The solid product which had separated was filtered off and dried in a vacuum oven at 25"C/12 mm. Hg. to constant weight. The product (44.7 parts) was obtained as a white powder.

The following table describes the prepara tion of other compounds in a similar manner to Examples 1 to 4 by reacting hexamethylene tetramine with the triazine having substituents Y and Z as indicated and also in the ratio m/n as indicated.

Reaction Example Y Z m/n Solvent Conditions 5 Cl N(CH3)2 2:2 chloroform 25 C/2 hrs.

6 Cl N(CH3)2 2:1 " " 7 Cl anilino 2:1 " " 8 anilino " 1:1 ., | 300C/1 hr.

9 OH N(CH)2 1:1 acetone/ 450C/3 hrs. chloroform 10 OH NH2 1:1 11 OCH3 OCH3 1:1 " 450C/4 hrs.

12 Cl N(CH)C6H, 2:2 chloroform 250C/2 hrs.

13 Cl | NHCH, 2:2 14 phenoxy phenoxy 1:1 15 " N(CH,)2 1:1 " 250C/3 hrs.

16 " NH2 1:1 " 250C/2Y2 hrs.

17 " NHCH3 1:1 18 " N(CH3)C6H5 1:1 250C/3 hrs.

19 o-cresoxy o-cresoxy 1:1 " 250C./3 hrs.

20 2,6-xylenoxy 2,6-xylenoxy 1:1 21 ochlorphenoxy o-chlorphenoxy 1:1 " 250C/4 hrs.

22 -naphthoxy -naphthoxy 1:1 " 25 C/3 hrs.

23 ohydroxyphenoxy NH2 1:1 Examples 2434.

A series of vulcanisable rubber compositions were prepared on a two roll-mill from the following ingredients: Natural rubber (Standard Malaysian Rubber Grade 5) 100 Zinc oxide 10 Stearic acid 3 High Abrasion Furnace Carbon Black 45 Processing oil 4 N-dicyclohexyl-2-benzothiazyl sulphenamide 0.7 Sulphur 4 s-triazine compound 2 Two samples each measuring approximately 4" X i" X 5/32" were taken from the above composition and lengths of brass-coatd steel cord were sandwiched between the two samples. The resultant sandwich was placed in a mould measuring 4" X i" X 5/16" and press cured for 30 minutes at 1530C.

After removal from the mould the force required to pull rhe individual cords out of the vulcanised block was measured.

In each case, a composition was made from the same materials identical in all respects except that the s-triazine compound was omitted, a similar vulcanised block was prepared, and the force required to pull the brass cords was measured for this "blank". The results are set out in the following Table.

's-triazine compound Force Force for blank Example Y Z m/n Ex. (kg) (Kg) 24 Cl anilino 1 1 67 48 25 Cl Cl 1 2 76 48 26 Cl NH2 2 3 71 46 27 Cl Cl 1.5 4 77 46 28 Cl N(CH3)2 1 5 69 46 29 Cl N(CH,)2 2 6 60 46 30 Cl anilino 2 7 73 50 31 anilino anilino 1 8 68 48 32 OH N(CH3)2 1 9 62 54 33 OH NH2 1 10 62 54 34 OCH3 OCH3 1 11 59 54 Examples 35--47.

Two 1100 decitex polyester cords were passed through a mixture of 100 parts of a mixture of two compositions, the first consisting of 60 parts of water, 25 parts of resorcinol and 14 parts of aqueous 37% formaldehyde and the second consisting of 310 parts of vinyl pyridine latex (41% solids) and 591 parts of water, and 100 parts of a solution prepared as described for solution A of Example 1 of British Patent Specification No. 1140528. Following the dip each treated cord was baked at temperatures of 1800C and 235"C. Portions of each cord were then moulded into a rubber compound prepared by mixing the ingredients below on a two roll mill and the whole then vulcanised by heating at 1530C for 30 minutes.

Natural Rubber (Standard Malaysian Rubber Grade 5) 100 Zinc Oxide 3.5 Stearic acid 1.5 General Processing Furnace Black 35 Processing oil 3.0 N-cyclohexyl-2-benzothiazyl sulphenamide 1.0 Sulphur 2.5 Additive (ommited from control rubber) 3 Portions of each cord were also moulded into a rubber compound which, except for the additive, was identical in all respects, to serve as a control.

Using an H-type test piece the force required to pull the individual cords out of the vulcanised rubbers were measured. The results set out in the following Table demonstrate the effect of the additive-treated rubber compared with control rubber on treated cord baked at 1800C and 235"C.

FORCE (Kg) ADDITIVE 180 C Bake 235 C Bake Example Y Z m/n Ex. Control Additive Control Additive 35 Cl N(CH3)2 2 6 8.0 10.5 12.2 12.1 36 Cl N(CH3)C6H5 1 12 8.0 11.4 12.2 12.9 37 Cl NHCH3 1 13 8.0 11.3 12.2 12.2 38 C6H5O C6H5O 1 14 5.3 9.9 9.2 11.3 39 C6H5O N(CH3)2 1 15 4.6 8.5 8.0 8.5 40 C6H5O NH2 1 16 4.6 7.9 8.0 7.6 41 C6H5O NHCH3 1 17 4.6 9.6 8.0 10.8 42 C6H5O N(CH3)C6H5 1 18 4.6 7.3 8.0 9.1 43 o-cresoxy o-cresoxy 1 19 4.9 9.1 9.6 10.8 44 2,6-xylenoxy 2,6-xylenoxy 1 20 4.9 10.0 9.6 11.8 45 2-Cl-phenoxy 2-Cl-phenoxy 1 21 4.9 9.6 9.6 13.1 46 2-naphthoxy 2-naphthoxy 1 22 4.9 9.2 9.6 10.8 47 2-OH phenoxy NH2 1 23 4.9 9.2 9.6 10.8

Claims

WHAT WE CI;AIM IS:

1. s-Triazine compounds of the general formula: [Triazine-(C1),] (HMT)0 (1) wherein m = 1, 2 or 3, Triazine (Cl)=, is a s-triazine compound having m atoms of chlorine and represented by the general formula:

wherein Y and Z are the same or different and each represents C1 or an optionally sub stituted hydroxyl, amino or mercapto group, HMT is hexamethylene tetramine and n is an integer less than or equal to m.

2. s-Triazine compounds as claimed in claim 1 wherein the substituent or substituents on the hydroxyl, amino or mercapto group is or are an alkyl group of 1 to 12 carbon atoms, cycloalkyl, alkenyl of 3 to 12 carbon atoms, phenyl optionally substituted by Cl, NO2, OH, C1-C4 alkyl or C1C4 alkoxy, naphthyl or, in the case of amino, a divalent radical making up a 5- or 6-membered heterocyclic ring with the nitrogen atom.

3. s-Triazine compounds as claimed in claim 1 wherein Triazine-(C1) is one of the compounds: cyanuric chloride 2-amino-4,6-dichloro-s-triazine 2-methylamino-4,6-dichloro-s-triazine 2-dimethylamino-4,6-dichloro-s-triazine 2-dimethylamino-4-hydroxy-6-chloro-s- triazine 2-anilino-4,6-dichloro -s-triazine 2-N-methylanilino-4,6-dichloro-s-triazine 2,4-dianilino-6-chloro-s-triazine 2,4-diphenoxy-6-chloro-s-triazine 2-amino-4-hydroxy-6-chloro-s-triazine 2-phenoxy-4-dimethylamino-6-chloro-s- triazine 2,4-diamino-6-chloro-s-triazine 2-phenoxy-4-amino-6-chloro-s-triazine 2-methoxy-4,6-dichloro-s-triazine 2-phenoxy-4-methylamino-6-chloro-s triazine 2,4-dimethoxy-6-chloro-s-triazine 2-phenoxy-4-N-methylanilino-6-chloro s-triazine 2,4-di-n-butoxy-6-chloro-s-triazine 2,4-di-o-cresoxy-6-chloro-s-triazine 2,4-di- (2,6-xylenoxy-6-chloro-s-triazine 2-amino-4- (m-hydroxyphenoxy) -6-chloro s-triazine 2,4dip( o-chlorophenoxy) -6-chloro-s triazine 2-methylamino-4- ( o-hydroxyphenyl ) -6- chloro-s-triazine, and 2,4-di-(fi-naphthoxy) -6-chloro-s-triazine.

4. s-Triazine compounds as claimed in claim 1 as herein particularly described in any one of Examples 1123.

5. A process for manufacture of the striazine compounds defined in claim 1 which comprises reacting a triazine compound of formula (2) therein with n molecular proportions of hexamethylene tetramine.

6. A process as claimed in claim 5 substantially as herein described with reference to and as illustrated by any of the Examples 1-23.

7. s-Trazine compounds as claimed in any of claims 1-4, whenever obtained by a process claimed in claim 5 or claim 6.

8. A method of bonding a rubber to copper or an alloy thereof which comprises adding to a vulcanisable rubber composition at least one triazine compound as claimed in any of claims 1-4 or 7, bringing the vulcanisable rubber composition into contact with the copper or alloy thereof, and heating the composite article to vulcanise the rubber.

9. A process as claimed in claim 8 wherein the.amount of s-triazine compound present in the vulcanisable rubber composition is between 1 and 5% by weight of the rubber.

10. A process as claimed in claim 8 substantially as herein described with reference to and as illustrated in any of the foregoing Examples 24-34.

11. A process for bonding rubber to shaped polyester bodies which comprises immersing the polyester in a vulcanisable rubber latex containing resorcinol and formaldehyde or a formaldehyde generator and/or reaction products thereof, baking the coated polyester, contacting the resultant coated polyester with a vulcanisable rubber composition containing a s-triazine compound as claimed in any of claims 1-4 or 7 and heating the composite article to vulcanise the rubber.

12. A process as claimed in claim 11 wherein the amount of s-triazine compound present in the vulcanisable rubber composition is between 1 and 5% by weight of the rubber.

13. A process as claimed in claim 11 substantially as herein described with reference to and as illustrated by any of the Examples 33-47.