DD279256A1 - RUBBER MIXTURES FOR THE PRODUCTION OF TECHNICAL RUBBER PRODUCTS BASED ON NATURAL AND / OR SYNTHESIS RUBBER - Google Patents

Abstract

The invention relates to rubber mixtures for the production of technical rubber products based on natural and / or synthetic rubber. It is used in the rubber processing industry for the production of black and light colored technical rubber products. The object of the invention is achieved by the expensive high active fillers are partially replaced by large-scale chemical processes waste products - Tonlaugungsrueckstaende and chlorinated kaolin - and thus a cost saving is achieved. In addition, an improvement in the physical-mechanical property values occurs.

Description

Field of application of the invention

The invention relates to kaichich mixtures containing, among other common Mischingingredienzien highly active fillers and are used for the production of technical rubber products.

Characteristic of the known technical solutions

It is known that in addition to natural and / or synthetic rubber, plasticizers, sulfur, accelerators and other conventional Mischingingredienien various fillers are taken into account in the Rezepturgestaltuno of rubber mixtures. The best known fillers are carbonaceous (carbon black, graphite, coke), silicate (precipitated silica, kaolin, clays) and mineral (chalk) fillers. These fillers have the task of giving the rubber mixtures certain physico-mechanical property values and moreover to act as an inert mass. Numerous variants of the use of a wide variety of fillers and their technological interference have been described in the literature.

In DE-OS 1959257, DE-OS 1959259 and DE-OS 3034747 the tendency is to replace the costly to manufacture carbon black as a filler by andore carbon components, for. B. by graphite.

This is intended to solve the mixing problem and prevent the formation of specks. The disadvantage here is that the costs increase, due to the higher cost of graphite.

Furthermore, in rubber mixtures various types of ground coke and Kohlönsorten, z. As charcoal, hard coal, anthracite, etc., used, which are also expensive and require treatment, such as inerting and impregnation, which is also described in DE-AS 1 592 909, DE-OS 1620829, DE-AS 2116417, US-PS 2378246 is.

In DE-OS 2004492 and DE-OS 3036874 rubber mixtures were added after special pretreatment silica and clays. Especially in light-colored mixtures with high dynamic stress, the silica is used, as the DE-OS 2343160 proves.

Several patents, such as GB-PS 876074, SU-UHS 219168, DE-OS 2504251, DE-OS 2640328, are concerned with the use of active and chemically loaded zeolites, which act on the one hand as a filler and on the other hand as an accelerator, acceptor or desiccant. In U.S. Patent No. 2,848,346, zeolites are used as a reinforcing filler to improve the strength of rubber products.

Likewise, JP-PS 7810618 utilizes activated mordenite for the vulcanization of synthetic rubber. It is u. a. increases the strength. The disadvantage is the high price of zeolites, which limits the use considerably.

In DD-PS 216945 was also proposed to use as fillers Ausbaumolekularsiebe, silicate slags and carbonaceous rods.

Object of the invention

The aim of the invention is to develop rubber mixtures in their recipe design so that they are more economical under normal technological conditions, d. h., Can be produced more cheaply and the performance characteristics of the rubber products are improved.

Explanation of the essence of the invention

The invention has for its object to develop rubber blends in which the possibility exists, the active fillers, beii pielswiese carbon black, partially replace and still di) good processing power is maintained and an improvement in the physical-mechanical property values ei is enough.

According to the invention the object is achieved by the active fillers are partially replaced by processed waste products, such as chlorinated kaolin and Ton laugungs residues that occur in some chemical companies.

In the thermal vulcanization of these rubber blends at temperatures ranging from 13O ⁰ C to 250 ° C was found that by the use of dried extraction residues of treated with boiling 12 to 21% hydrochloric acid clays

or alumina-containing minerals which an SiO ₂ content of 70-95% and an Al ₂ O 3 content of less than 10% possess hereinafter called Tonlaugungsrückstände and chlorinated kaolin -, a considerable improvement of physico-mechanical property values of the vulcanizates is achieved.

Preference is given to using a silicate-rich clay leachate residue close to twice the extraction of the clays or clay-containing minerals with hydrochloric acid, according to composition II of the following table:

ingredients composition Type I Type II simple leaching double leaching 74.0 80.0 SiO ₂ 9.2 3.5 Al ₂ O ₃ 0.8 0.5 Fe ₂ O ₃ 3.4 4.2 TiO ₂ ad. 100 ad. 100 rest

It has been found that the improvements in the property values of the vulcanizates are achieved, above all, in the case of dark rubber mixtures in a proportion of 1 to 20% and in light rubber mixtures in a proportion of 1 to 35% of the filler of type II, based on the total mass of the Mixture, is present.

Another advantage of the filler II is the one-step interference and requires no additional technological steps.

The use of the filler type II is carried out after a pretreatment - drying, grinding, sieving - by conventional methods in grain fractions between 0.1 to 100μπι, preferably 0.1 to 40mm.

The rubber mixtures according to the invention surprisingly improved the quality of the dynamic characteristics of the vulcanizates, such as. B. impact resilience, loss factor tan δ, dynamic modulus of elasticity, specific and relative damping over the pure soot, silicic acid or kaolingbefüllten rubber mixtures.

In the case of light vulcanizates, above all, a higher crosslinking density and a higher impact resilience were found. Moreover, when chlorinated kaolin was used, an increase in the rate of cure was observed, resulting in an improved mass / time yield and acting on slow cure systems.

The rubber mixtures according to the invention are therefore advantageous, since fillers are used which are obtained in large quantities as waste products and have so far fulfilled no specific purpose.

The rubber blends according to the invention are explained in more detail below with reference to exemplary embodiments.

embodiments Example 1:

The rubber mixtures were prepared in a laboratory internal mixer of the type GK4 N according to the usual mixing instructions. The characteristic values were determined and evaluated according to valid TGL regulations:

Test formulation:

conventional mixture according to the invention mixture

ingredients

1 2 3

Mass shares in%

NR elastomer

SBR elastomer

1,4-cis-polyisoprene elastomer

naphthenic plasticizer

HAF

stearic acid

zinc oxide

sulfur

Benzthiazylsulfencyclohexylamin

Clay residue (dried)

chlorinated kaolin

- Composition of the leaching residue:

42,00 42,00 42,00 16.00 16.00 16.00 42,00 42,00 42,00 10.00 10.00 10.00 50,00 40,00 40,00 1.00 1.00 1.00 5.00 5.00 5.00 1.70 1.70 1.70 1.30 1.30 1.30 _ 10.00 _

80.0%

3.5%

0.5%

4.2%

= ad. 100%

10.00

The Tonlaugungsrückstand wurae obtained by double leaching of clay with 20% hydrochloric acid at boiling temperature. - Composition of the chlorinated kaolin:

Al ₂ O ₃ · 2SiO ₂ • a poorly soluble product with solid Si-O-Al bonds

By chlorination at higher temperatures (80 ° C to 11O ⁰ C), the bond is split, but without accumulating chlorine. The product becomes reactive, soluble in alkalis and gets chemisorptive properties. It is thus used to make special aluminosilicate compounds with a large internal surface area.

Characteristic values of dark-colored mixtures and characteristic values of the vulcanizates:

characteristics

fillers

(% Data based on the filler content of the mixture)

100% carbon black '80% carbon black 80% carbon black

20% Tonlaugungsrückstand

SBR elastomer 100 100 100 Silica K 605 60 - 30 kaolin - 60 - chlorinated kaolin - - 30 naphthenic plasticizers 10 10 10 stearic acid 1.0 1.0 1.0 zinc oxide 5.0 5.0 5.0 sulfur 2.0 2.0 2.0 Benzothiazylsulfencyclohexylamin 1.50 1.50 1.50

20% chlorinated kaolin

1. vulcanization behavior at 150 ^c C: 5.2 9.6 3 8.4 scorch (t _{2 in} min) 9.8 15.1 12.7 Ausvulkanistions? Ince It ₉₀ in min) 18 12 17 minute Torque (RE) 62 53 57 Max. Torque (RE) 2. Static characteristics: 15 15 15 optimal heating time at 15O ⁰ C (Min) 16.8 16.1 17.4 Tensile strength (MPa) 563 545 612 Elongation at break (%) 27 32 34 Impact resilience (%) 53 50 51 Vulcanization hardness ( ³ Sh A) 21.8 19.1 24.1 WeiterreißwiderstandiNmm '') 3. Dynamic characteristics: 0.163 0.145 0,136 Loss factor tan δ 6.0 4.2 6.2 more complex dynamic Young's modulus (MPa) 5.9 4.2 6.1 elastic stiffness (MPa) 0.9 0.7 0.5 viscous stiffness (MPa) 0.365 0,254 0,178 specific damping (Jr ¹ ) 51 42 44 static spring constant (ISImm "') 35 32 28 relative damping (%) example ^ conventional invention ingredients mixture mixture 1 2 Concentration Mass shares in%

Properties of the light-colored mixtures and characteristics of the vulcanizates:

characteristics

K 305 kaolin 100% 100% 1. vulcanization behavior at 150 ° C scorch 108 9.6 (t ₂ -min) Ausvulkanisationszeit 24.9 27.2 (Tgo-min) Crosslink density (RE) 47 43 minute Torque (RE) 21 18 Max. Torque (RE) 68 61 2. Phys.-med. property values optimal heating time at 30 30 150 ⁰ C (min) Tensile strength (MPa) 5.1 3.9 Elongation at break (%) 378 492 Vulcanisate (° ShA) 81 62 Impact resilience (%) 25 28 Tear resistance (Nrnm " ¹ ) 3.9 6.4 Abrasion (mm ³ ) 225 287

fillers

(% Data based on the filler content of the mixture)

'"K605 50%

chlorinated kaolin 50%

8.2 17.4

56 13 69

30

6.4 312 68 38

10.4 184

In both examples, it can be seen that in the case of important parameters (tensile strength, impact resilience, tear propagation resistance, abrasion) an improvement by the rubber mixtures according to the invention occurs both in dark and in light mixtures.

Claims (3)

1. Rubber mixtures for the production of technical rubber products based on natural and / or synthetic rubber, highly active fillers and other conventional Gemischingredredienzien, characterized in that the highly active fillers partially by waste products, such as clay leaching residues and chlorinated kaolin, with 5 to 40%, preferably 20%, based on the total amount of filler to be replaced. 2. Rubber mixtures according to claim 1, characterized in that the proportion of the substitute fillers, based on the total mass of the rubber mixtures, 1 to 35 parts by mass in%. 3. rubber mixtures according to claim 1, characterized in that the Tonlaugungsrückstände from with boiling 12 to 21% hydrochloric acid treated clays or clay-containing minerals, which has a SiO ₂ content of ¹ 0 to 95% and an Al ₂ O ₃ content of less than 10% exist.