DE1301481B - Process for the vulcanization of rubber compounds using phenolic resins - Google Patents

Description

It is well known that rubber compounds of the most varied of types can pass through Phenolic resins are vulcanized by alkaline condensation of formaldehyde with phenol or substituted, at least bifunctional phenols are.

To accelerate and intensify vulcanization, the Mixtures of one or more halides of metals of II. Or III. Group of Periodic table or heavy metals. The metal halides can also be used in the mixtures themselves from compounds acting as halogen donors, such as chlorosulfonated polyethylene or polychloroprene, and thus reactive in the heat Metal compounds such as oxides or salts of weak acids. getting produced.

It is also known that the rate of vulcanization of Rubber compounds depends on the amount of metal halide formed and by Rolling or kneading the mixtures at higher temperatures before adding the resin can be accelerated.

According to the known method, vulcanizates can be with very produce good properties. which, especially in the case of butyl rubber-phenolic resin vulcanizates, characterized by good aging resistance. The implementation of the vulcanization of rubber mixtures through phenolic resins, hereinafter referred to as resin vulcanization. is nevertheless associated with difficulties because of the metal halides added to the mixtures either difficult to incorporate or because of their activating effects is too low. The aforementioned heat treatment of the mixture before adding the resin enables a quick vulcanization. but is associated with an additional effort.

It is also known from US Pat. No. 2,489,340 to use natural rubber, Butadiene-styrene rubber or butadiene-acrylonitrile rubber with sulfur and a organic vulcanization accelerator with the addition of trichloromethylarwl compounds to vulcanize. The vulcanization is due to the addition of the aryl compounds, however only slightly accelerated. Since this is already one of sulfur and one Organic accelerator existing vulcanization system is the additive the aryl compounds are not absolutely necessary for vulcanization.

US Pat. No. 2,567,135 describes the vulcanization of butadiene-styrene rubber described in the presence of o-chlorobenzotrichloride.

The vulcanization takes place in the presence of lead and without phenolic resins performed. This is a completely different reaction mechanism than when using of phenolic resins. In addition, there are vulcanizates with relatively low Obtain strength values that are not sufficient for all purposes.

In contrast, the invention relates to a method for vulcanizing rubber mixtures using phenolic resins in the presence of halogen-containing compounds. It has now surprisingly been found that these mixtures can be vulcanized quickly if halogen compounds of the general formula are used to accelerate the vulcanization can be used, where X is halogen. preferably bromine or chlorine. Y and Y 'represent halogen, preferably bromine or chlorine, hydrogen or a hydrocarbon radical with up to 6 carbon atoms and and Y' can be the same or different.

The process according to the invention makes the incorporation more halogen-containing Additions made easier, so that the previous difficulties are overcome.

The proposed compounds are characterized by a proportionate faint odor of hydrogen halide and can be excellently integrated into the Work in rubber mixture. They are generally used in amounts from 0.1 to 10. preferably 1 to 5 parts by weight per 100 parts by weight of the elastomer and give even when using small amounts of phenolic resin, e.g. B. less than 6 parts by weight per 100 parts by weight of the elastomer, even after short vulcanization times Vulcanizates with excellent properties. Most importantly, they have a very high level Tensile strength and favorable tension values.

Particularly suitable compounds are diphenylbromomethane and Diphenylchloromethane. also diphenyldibromomethane, triphenylbromomethane. Triphenylchloromethane and benzotribromide.

The acceleration of vulcanization is in itself already due to the claimed connections causes itself. To produce well age-resistant Vulcanizates, however, include the use of oxides and / or salts of weak acids of metals of the 11th and 111th groups of the periodic table or of heavy metals - that Metals with a specific gravity of over 4 are useful. Are suitable z. B. the formates, acetates, lactates, stearates. Benzoates. Silicates and carbonates of magnesium, aluminum. Cadmium, calcium, titanium. Chrome. Beryllium. Lead, manganese.

Cobalt. Nickel, antimony. Zinc. Iron and Zinc: preferably used one zinc oxide. Zinc-. Iron or tin stearate. Also the basic salts like Sn (OH) CI or mixtures of several of the aforementioned compounds can be used.

The amount of added metal compounds can be within wide limits vary. In general, 0.1 to 10 parts by weight are preferably 1 to 5 parts used per 100 parts by weight of the elastomer. The use of smaller amounts is particularly useful if the rubber mixtures are used before the phenolic resin is added hot rolled or kneaded. In this case, the best effects are achieved. when the metal compound and the claimed halogen compounds are equivalent Ratio to each other, based on metal and halogen, are used.

The di- or polyalkylol compounds are suitable as vulcanizing agents of the phenol and / or in the p- or o-position and! or in one or both m-positions substituted phenols and bisphenols, as well as those resulting from further condensation of these High molecular weight resins obtainable from alkylol derivatives.

For the sake of simplicity, these products are referred to below as »phenolic resins " designated. They are generally based on alkaline condensation lying phenols with one or more aldehydes with 1 to 7 carbon atoms, preferably with formaldehyde, and contain at least two to four per molecule terminal alkylol groups.

Such phenolic resins are therefore also suitable. the more than two responsive Groups contained in the molecule and which are cross-linked to form a multidimensional structure for themselves Leftovers can harden. These resins become crosslinking agents in rubber compounds for rubber, the self-hardening of the resins largely not taking place.

Suitable resins are e.g. B. obtained by further condensation of the following monomolecular di- or polymethylol compounds: R ', R2, R3, R and R5 can be identical or different. They mean H or a hydrocarbon radical having 1 to 12 carbon atoms or another group which does not react with the elastomer, e.g. B. Nos or Halogen. R'to R5 should expediently not contain more than 14 carbon atoms together. R 'should preferably contain 4 to 8, R2 and R3 together preferably contain up to 5 carbon atoms. As substituents are z. B. called the methyl, ethyl, propyl, isopropyl, tert-butyl, amyl, diisobutyl, nonyl, cyclohexyl, phenyl, benzyl, tolyl, xylyl radical.

Phenolic resins other than methylol groups can also be used still contain halomethyl groups: The methylol groups of phenolic resins can be completely or partially etherified by aliphatic or aromatic alcohols. z. B. by the monohydric alcohols corresponding to the alkyl radicals mentioned, such as Ethyl, propyl, butyl or benzyl alcohol. They can also be organic as ester groups Acids are present. The phenolic hydroxyl groups can also optionally be esterified be.

The presence of methylol end groups in the phenolic resins is preferred for their crosslinking effect, but not absolutely necessary. Resins which can also be used as vulcanizing agents are those which are formed from dimethylolphenol compounds by cyclic condensation and to which the general formula VI applies, in which n is the number of ring members; n is an integer. at least 2, preferably 3 to 8.

In this formula, the CH, OCH-. 7 groups partly also through CH bridges be replaced. however, the reactivity of the condensates decreases as the proportion increases of the - CH2 bridges. Those occurring in practically all phenolic resins are reactive, methylene ether groups -CH2-O-CH- connecting two phenol nuclei. who look like two Behave methylol groups.

The phenolic resins can be solid, powdered or dissolved Resins can be used. To carry out the vulcanization, per 100 parts by weight Rubber generally 0.5 to 8 parts by weight. preferably 2 to 6 parts by weight, needed.

The crosslinking effect increases as the amount of resin increases.

The rubber mixtures can be produced in a manner known per se, processed and vulcanized. The order in which they are mixed can be anything to get voted. It is only necessary that the best possible distribution of all components of the mixture is achieved. To improve the properties of the vulcanization products can it may be advantageous to keep the mixtures hot, e.g. B. at a temperature of 100 to 200 ° C, to be rolled or tempered. It is always advisable to use fillers as well which obviously influence the vulcanization process. For example, you get with active carbon blacks vulcanizates with higher strength than with silicas and kaolins. Furthermore, anti-aging agents, such as derivatives of p-phenylenediamine, plasticizers and processing aids of various kinds, e.g. B. fatty acid salts, paraffins and waxes can also be used. When adding basic auxiliaries, it is advisable to to check beforehand to what extent they have the activating effect of the invention cancel added substances.

According to the invention, the most varied types of rubber can be vulcanized be e.g. B. natural rubber, butyl rubber, butadiene-styrene rubber, butadiene-acrylonitrile rubber, Polyisoprene, polybutadiene, ethylene-propylene-diene (e.g. dicyclopentadiene) terpolymers, Polychloroprene. or mixtures of these rubbers. The vulcanized ones obtained Products are suitable for the manufacture of brake linings. Shiauchen.

Seals. Shoe soles, tire materials and technical rubber goods.

The invention is illustrated by the following examples and percentages are parts by weight.

Percentage by weight, 'For the properties of the vulcanization products the following abbreviations are used: @ = N'ulcanization time (minutes).

Z = tensile strength (kg cm ').

D = elongation at break zozo M 15 () = stress value at 15% elongation (kg cm2).

M 300 = tension value at 300 "n elongation (kg cm2).

BD = permanent elongation (%).

KZ = notch toughness (kg cm).

H = hardness (Shore A), R = rebound elasticity (%), PL = plasticity the unvulcanized mixture (Defo).

For example, comparison of a mixture produced according to the invention with several mixtures produced according to known processes. mixture I II III IV Butyl rubber (1.5 to 2.0 mole percent un- s # saturation). . . 100.0 100.0 96.0 100.0 Polychloroprene. ... - 5 - - Chlorosulfonated poly Bromobutyl rubber .. - - 2 - Dipenylbromomethane .. 3.0 - - - SnCl2 # 2H2O ... .. - - - 2.0 Paraffin ... - - 0.5 - Stearic acid ... 1.0 - - 1.0 Zinc oxide .... ... 2.0 5.0 2.0 - Highly abrasion-resistant oven soot .......... ...... 50.0 50.0 50.0 50.0 Resin from p-lsooctylphe- nol and about 2 moles condensed Formaldehyde. 3.0 6.0 6.0 3.0 vulcanization temperature rature (C). . . 160 160 160 155 The mixtures were prepared on the basis of the mixing instructions for butyl rubber mixtures produced on the watze contained in Butyt-Information No. 3 of Esso (October 1957).

The phenolic resin and the halogen compound were incorporated in place of the sulfur specified there. The vulcanizates had the following properties: @ 7th DM 150 M 300 DB KZ HR PL Mixture 1 20 137 589 18 59 15 19 56 6 70 60 40 143 569 20 66 13 18 57 6 60 144 541 22 72 12 17 59 6 A * 150 7 60 111 346 35 95 14 19 61 7 Mixture II 20 54 1092 7 13> 65 12 55 6 80 70 40 93 792 11 27> 65 19 59 6 60 133 647 21 53 26 18 62 6 A * 150 7 60 122 223 77 8 15 82 10 Mixture III 20 75 915 8 17> 65 15 60 6 76 66 40 130 682 17 46 31 23 63 6 60 145 601 21 63 14 24 65 6 A 150 7 40 116 264 55 - 11 12 75 8 Mixture IV 20 138 389 27 97 7 15 58 6 81 72 40 156 336 44 139 4 12 61 6 60 150 286 53 - 3 10 63 6 A 150 7 40 92 156 89 - 2 8 70 7 * Test values of the samples aged for 7 days at 150 C in the air drying cabinet.

The comparison of the mixture prepared according to the invention I with the mixtures II to IV prepared by known processes results in: The under Using SnCl2 # H2O vulcanized mixture IV vulcanizes the fastest. but there are vulcanizates with very low elongation and very high stress values. Mixtures of this type are therefore unsuitable for many purposes. she are too stiff and do not have sufficient mechanical resistance with dynamic loading. Is particularly disadvantageous. that the SnCl. 2 # 2H2O is difficult to incorporate and the test values of the vulcanizates fluctuate strongly subject.

In contrast to mixture IV, mixtures I to III do not contain any Metal halide. The rapid vulcanization of those produced according to the invention Mixture I results from a comparison with mixtures II and III.

Mixture I gives vulcanizates after just 20 minutes of vulcanization with good physical properties, which is particularly evident from the tension value 300% elongation and the low permanent elongation. With aging (Mixture IA) the permanent elongation increases only slightly, and the elongation at break remains sufficiently large at over 300%.

Mixture II, on the other hand, vulcanizes much more slowly, although it does contains twice as much phenolic resin.

Only after a vulcanization time of 60 minutes are approximately the same Properties achieved as with mixture I after 20 minutes. The high values of the lasting However, elongation shows that the crosslinking in mixture II is less favorable overall runs. Vulcanization only really gets going and takes place when it ages to a strong hardening of the vulcanizate.

Mixture III cures faster than Mixture 11, but always much slower than mixture I. This is particularly evident in the low Tension values and the large permanent elongation. With aging there is a strong post-vulcanization takes place, which is similar to mixture II to a strong Decrease in elongation at break and a sharp increase in stress values.

Overall, the mixture produced according to the invention is notable compared to the other compounds due to simple production, very fast vulcanization and good aging resistance, in particular due to a very small increase in Hardness.

Mixtures corresponding to Mixture I without zinc oxide vulcanize for example same fast, but give less aging-resistant vulcanizates.

If the mixture prepared according to the invention I before adding the Phenolic resin subjected to a heat treatment, e.g. B. by hot rolling during 10 Minutes at temperatures of 160 to 200 ° C or by annealing, e.g. B. 50 minutes at 200 the vulcanization proceeds even faster. The same effect is achieved if the mixture is mixed hot from the start.

Equivalent vulcanization effects are obtained if in place of the p-octylphenol resin, resins made from p-tert-butylphenol, p-amylphenol or p-nonylphenol be used.

EXAMPLE 2 Very rapid vulcanization can also be achieved with the aid of diphenylchloromethane or triphenylchloromethane. The mixtures were prepared as indicated in Example I. mixture V Vt I Vil Vill Butyl rubber (see game 1) ................. 100 100 100 100 Stearic acid I 1 II Zinc oxide 3 3 3 2 mixture v vi Vll Vlll Highly abrasion-resistant oven soot 50 50 50 50 Diphenylchloromethane 3 4 4- Triphenylchloromethane --- 4 p-isooctylphenol resin (see example 1) ................. 3 3 6 3 Test data of the vulcanizates IZD MI150 M300 BD KZ HR PL Mixture V vulcanization temperature 160 ° C 20 120 644 16 48 233 22 54 6 73/63 40 129 631 19 55 24 22 56 6 60 132 619 19 57 22 23 56 7 Mixture VI vulcanization temperature 160 ° C 20 121 669 16 49 27 22 55 6 73/63 40 127 639 18 54 25 24 56 6 60 127 607 19 56 21 22 55 6 Vulcanization temperature 150 ° C 20 107 706 14 38 41 20 55 6 40 119 631 16 48 29 22 55 6 60 118 570 18 53 20 22 56 6 60 118 570 18 53 20 22 56 6 Mixture VII vulcanization temperature 160 ° C 20 132 679 19 55 19 25 56 5 73/62 40 132 576 23 67 13 28 59 5 60 136 556 25 73 11 22 59 5 Mixture VIII vulcanization temperature 160 ° C 20 92 651 10 30 55 16 S5 6 70/60 4011166611364417566 60 117 667 14 42 41 17 57 6 According to the test values, the mixtures V to VIII produced according to the invention also vulcanize more quickly than the mixtures II and III, which describe the prior art, listed in Example I, although the latter 6 parts of phenolic resin per 100 parts of rubber, the mixtures V, VI and VIII on the other hand contain only 3 parts of phenolic resin per 100 parts of rubber. It is also shown that the vulcanization can be carried out with good success even at 150 ° C.

Are in place of diphenylchloromethane and triphenylchloromethane other halogen compounds used, e.g. B. dibromopropanol, cyclopentyl bromide, Stearyl bromide, lauryl bromide or phenyl iodide chloride, it becomes a much weaker one Vulcanization effect achieved.

Example 3 Butyl rubber mixtures can be prepared with the aid of diphenylbromomethane also through bisphenol resins vulcanize, also a quick one and vigorous vulcanization effect is achieved.

Mixture IX butyl rubber (see example 1) 100 paraffin ................. 0.5 diphenylbromomethane. 3 zinc oxide .. 3 Highly abrasion-resistant furnace soot ..... 50 bisphenol resin *. 6, 0 * Commercially available bisphenol resin, made from p, p'-dihydroxydiphenylpropane by the addition of 4 moles of formaldehyde in an alkaline medium and etherification of the initially formed tetramethylol compound with butanol.

Preparation of the mixture as indicated in Example 1. Vulcanization temperature 160 C.

Test data of the vulcanizate t ZDM 150 M 300 BD KZ HR PL 20 100 446 22 58 21 15 66 9 61/51 40 110 414 29 73 17 14 70 9 60 110 373 31 80 13 15 70 10 A 150 7 40 83 279 43 - 16 13 78 10 Example 4 Mixture X butadiene-styrene rubber (styrene content approx. 23%) .... 100.0 stearic acid ........ . . 1. 0 zinc oxide ..................... 3, 0 diphenylchloromethane 2. 0 highly abrasion-resistant furnace carbon black 50, 0 phenolic resin made from p-tert.-butylphenol .. 6, 0 The mixture is produced as described in Example 1.

Test values of the mixture vulcanized for 40 minutes at 155 ° C: tensile strength 207 kg / cm2, elongation at break 4100 / o, stress value at 3000 / o elongation 136 kg / cm2, permanent elongation 8%, hardness according to Shore A 61.

Instead of the bisphenol resin you can have practically the same effect trifunctional phenolic resins can be used as vulcanizing agents. Such resins are made by the addition of 2 to 3 moles of formaldehyde to phenol or one in the m-position substituted phenol obtained, it is advantageous to use the methylol groups To etherify monoalcohols.

Claims (3)

Claims: 1. Process for vulcanizing rubber mixtures by phenolic resins in the presence of halogen-containing compounds, characterized in that halogen compounds of the general formula are used to accelerate vulcanization can be used, where X is a halogen, Y and Y 'are halogen, hydrogen or a hydrocarbon radical having up to 6 carbon atoms and Y and Y' can be the same or different. 2. The method according to claim 1, characterized in that mixtures vulcanized, the oxides or salts of weak acids of metals of the II. or III. Group of the Periodic Table or Heavy Metals included. 3. The method according to claim 1 or 2, characterized in that mixtures are vulcanized before the addition of the phenolic resin at temperatures mixed above 100 ° C or rolled or tempered for some time at temperatures above 100 ° C have been.