CH224218A - Process for the production of condensation products from phenols and low molecular weight aldehydes. - Google Patents

Description

  

  Process for the production of condensation products from phenols and low molecular weight aldehydes. The present invention relates to a process for the production of condensation products from plenolischen substances and low molecular weight aldehydes, in particular formaldehyde.

   Instead of the free aldehydes, their Polymerieations- products such. B. Paaraldehyd., Or those substances which split off formaldehyde in the course of the reaction, z. B. hegamethylene tetramine can be used. In this way, masses are obtained which are known as phenoplasts.

    



       Among the phenols; Starting materials hard so far the m-cresol has gained special importance because it hawzarti:

  It supplies condensation products which, through further heating to certain temperatures, are transformed into an insoluble and infusible product that is capable of a wide range of technical applications.



  For the production of shaped structures from these resinous masses, however, their brittleness has proven to be disadvantageous. To improve the mechanical properties, especially the flexural strength and impact resistance,

   fillers, in particular fibrous materials or wood flour, have been incorporated into the phenoplast masoa, which, however, render the masses opaque and discolored. It has also already been proposed for this purpose that the residue remaining after the saccharification of the wood,

          commonly known as "liggnin". Although this improves the mechanical properties, other Naohteile must be accepted.

    This also makes the masses impervious and discolored.



  The method according to the invention forms a further aspect of the last-mentioned method,

      in which an alkaline solution @ the same is used in the condensation of phenolic substances with low molecular weight aldehydes on the steel of the residue remaining from the saccharification of wood.



       The alkaline solution of the wood sugar residue, which is referred to below as "lignin" for short, is obtained by boiling the lignin in alkaline solutions, in particular in alkaline solutions.

         It is boiled until the lignin has essentially gone into solution; then the undissolved fractions are filtered off and the filtrate is evaporated, which is then ready for use.



       When phenolic substances condense with low molecular weight aldehydes in the presence of the alkaline lignin solution described above, the same reactions occur as in the known process,

      where Lignnn is used as such. The products obtained are characterized by excellent mechanical properties and above all by excellent impact resistance (insensitivity to impact),

   are, however, translucent and generally brighter.



  Of low molecular weight aldehydes, formaldehyde or its polymers or substances which split off formaldehyde in the reaction are primarily suitable for the process.



       The addition of alkaline catalysts, which is customary for the condensation, is completely or partially unnecessary in view of the alkaline reaction of the lignin solution.



  Of the phenolic Stoffei not only those phenols can be used as starting materials, which have been used ver with advantage, such.

       B. the metacresol or the symmetrical xylenol, but also those phenols which are little or not suitable for synthetic resin formation.



  The properties of the products that can be achieved with the process according to the invention can be largely varied by varying the working conditions. Depending on the duration of the condensation and depending on the amount of lignin, viscous, kneadable or, at ordinary temperature, solid products can be obtained that are either meltable or remeltable.

           The invention is explained using a few examples:

       1. 5 parts by weight of anhydrous lignin, which is obtained from wood processing,

          are boiled with 5 parts by weight of potassium hydroxide and 50 parts by weight of water until foaming. and abfistriert,

            whereupon the filtrate is evaporated to 20 parts. After cooling, 10 parts by weight of o-kmesol and: 25 parts by weight of <I> 40 </I> 3% formaldehyde are added.

   The whole thing is mixed thoroughly and slowly added until a layer separation occurs and the resin layer has reached a state in which it is no longer possible to

   create an emulsion in cold water. The aqueous layer is then separated off and the condensation product obtained is processed in the manner customary in the synthetic resin industry.



  2. 80 parts by weight of 2,4-xylenol and 66 parts by weight of formaldehyde 40% 1 g are mixed with 14 parts of the lignin conversion product obtained according to Example 1 and slowly heated until the layer is

  separation and until the resin has reached a stage in which it is no longer possible to create an emulsion in cold water. Then you cool off

          Pour off the upper aqueous layer and evaporate the residue to the desired consistency. The further processing takes place in the usual known manner.



  3. Mix 60 parts by weight of phenol and 75 parts by weight of 44% formaldehyde with 8 parts of RTI ID = "0002.0258" WI = "10" HE = "4" LX = "1400" LY = "1681"> obtained in accordance with example 1 alkaline ligament solution and mixed according to Examples 1 or 2

  further treated.

 

Claims (1)

PATENT CLAIM: Process for the production of resinous condensation products from phenolic.substances, low molecular weight aldehydes and residue called lignin, which occurs during the saccharification of wood, characterized in that this residue: is used in an alkaline solution.