CH299373A - Process for the production of moldings from elastomers. - Google Patents

Description

  

      Process for the production of moldings from elastomers. The natural silicates that have been used as fillers up to now have fixed physical and chemical properties as minerals that limit their usability. In contrast to this, the synthetic silicates produced as precipitated products allow extensive adaptation to the intended use.



  The present invention relates to a method: for the production of moldings from elastomers, which is characterized in that precipitation products from water glass solutions with salt solutions of the elements of the 2nd to 4th

       Group of the periodic system with a molar ratio of metal oxide to Si02 smaller than 1 can be used as fillers.



  Your usability extends. For example, in all areas in which, in addition to purity and grain size, the internal structure or activity of the smallest particles is important, or resistance to chemical and mechanical influences, adhesion and absorbency. The physili:

  The metallic and chemical properties of the precipitated silicates allow a very extensive variability in the composition of the filler with regard to the ratio of metal oxide to silica and thus at the same time an adaptation to the requirements imposed by the intended use.

    The properties of the silicates depend on their content of silica, water and bases as well as on the concentration and temperature of the solutions used in the precipitation, their pH values and on the drying temperatures of the precipitated products.



       The elements of the?. to 4th group of the periodic system, for example Mg, Ca, Sr, Ba, Zn, Al, Ti, one or more.



  Dilute alkali silicate solutions are preferably used to produce the fillers. Salt solutions:

      of the elements mentioned in compliance with such pH values of the real tion liquid implemented that on the one hand precipitates of the desired composition arise, on the other hand the filtrate is as low as possible in silica. To improve the filtration, the reaction is expediently carried out at an elevated temperature, such as 90 C, and, in constant motion, while the p,

  1 value is kept in the weakly acidic to alkaline range in order to avoid silica losses, i.e. between 3 and 11. In this way, products that are very high in silica can also be obtained with good yield.



  Leave the washed-out precipitation products. dry themselves to a large extent and tolerate drying temperatures of around 200 to 300 C without diminishing their suitability for fillers in contrast to the water-rich :, heat-sensitive; Gels; the dehydration of the precipitated silicates can therefore be carried out cheaply.



  Since the precipitation products prepared in the manner indicated with. 'High degree of fineness - if there is a large inner surface, they can be used to advantage in the elastomer industry where the use of the finest fillers is important. In the rubber industry, they impart particularly desirable properties to rubber in terms of color, elongation and strength at break, elasticity and tensile strength, abrasion figure of merit, etc.



  <I> Embodiments: </I> 1. One as a filler for rubber mixtures; A suitable powdery substance is prepared as follows: 680 kg water glass solution 37 B6 and 4 m3 of water are precipitated in the agitator at 90 C with 1.22 one-percent MgCl2 solution so that the pH of the precipitating liquid is 9.5 . After stirring for a further two hours at 90.degree. C., it is filtered off, washed and dried at about 120.degree.

   Yield 220 kg Mg silicate with a molar ratio Mg 0: SiO 2 = 0.24 with a 13.8% loss on ignition.



  The product obtained is incorporated as a filler in a rubber mixture of customary composition, from which shoe soles are produced.



  2. A rubber filler is prepared as follows: 1360 kg. Water glass solution 37 Be and 8 m3 of water are mixed with a solution of 600 liters of hydrochloric acid 1.16, 4.4 m3 of water and 500 kg of CaC12 in the agitator at 90 C until the precipitating liquid has a pH = 7.

   After another two hours of stirring at 90 ° C, it is filtered, washed and dried at about 120 ° C. Yield 325 kg Ca-silicate with a molar ratio Ca0: Si02 = 0.04 with 11.2% loss on ignition.



  The product obtained is used as a filler for rubber compounds for shoe sole production.

 

Claims (1)

PATENT CLAIM: 11: Process for the production of moldings from elastomers, characterized in that precipitation products from water glass solutions with salt solutions of the elements of the 2nd to 4th group of the periodic system in a molar ratio of metal oxide to SiO2 smaller than 1 are used as fillers. SUBCLAIMS 1. The method makes patent claim, characterized in that fillers are used, during the precipitation of which such pH values of the reaction liquid were maintained that the filtrate was as low as possible in silica. 24. The method according to claim, characterized in that fillers are used, which were filled out at elevated temperature and strong movement. 3. Method according to claim and dependent claim 1, characterized in that the pH is in the weakly acidic to alkaline range. was held.