METHOD FOR PREPARATION OF PHENOL-FORMALDEHYDE RESINS OF THE NOVOLAK TYPE - CZECHOSLOVAK SOCIALIST REPUBLIC INVENTION SPECIFICATION PERTAINING TO A CERTIFICATE OF AUTHORSHIP NO.171552

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Describes a method for preparing phenol-formaldehyde resins of the novolak type, modified with polymers, by condensing phenols with formaldehyde using acid catalysts and stabilizing with tertiary amines during dehydration. Modification addresses limitations of unmodified novolaks in molding, bonding agents, and resin performance. The process incorporates 6-caprolactam and its cyclic/linear oligomers into the phenol-formaldehyde reaction, enabling vacuum-free dehydration to unusually high temperatures (200℃ and higher) and allowing formaldehyde molar excess.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages42

Reading Time1 h 46 min

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Method for Preparation of Phenol-Formaldehyde Resins of the Novolak Type

Condensation, acid catalysis, and tertiary-amine stabilization

Modification with 6-caprolactam and its oligomers

Vacuum-free dehydration and resulting resin properties

Ciernik,J.,and others Method for preparation of phenol-for-maldehyde resins of the novolak type.7 p. Patent(Czecheslovak)No.171552(1978).Filed: TRANSLATION NO.4416 知 g Czechoslovak Patent No.171552 416 Int.c1.²: Filed: Application No.: Open to Public Inspection: Published: Inventors: # METHOD FOR PREPARATION OF PHENOL-FORMALDEHYDE RESINS OFTHE NOVOLAK TYPE The invention pertains to a method for preparation ofphenol-formaldehyde resins of the novolak type,modified withpolymers,by condensation of phenols with formaldehyde in thepresence of acid catalysts and stabilization with tertiaryamines during dehydration. The range of applications of phenol-formaldehyde resinsof the novolak type,modified with various monomeric and # CZECHOSLOVAK SOCIALIST REPUBLICINVENTION SPECIFICATION PERTAINING TO ACERTIFICATE OF AUTHORSHIP NO.171552 C 08 G 8/28C 08 G 8/10 September l6,1974 PV 6328-74 February 27,1976 February 15,1978 Jan Ciernik,Brno;Vladimir Kubanek,Kralupy nad Vltavou;Jaroslav Kralicek,Jaroslava Kondelikova,Jan Morava,Prague;Jiri Budin,Sezimovo Usti Digitized by the Internet Archivein 2019 https://archive.org/details/methodforprepera00cier Page 2 polymeric compounds,is very wide. Their application is especially advantageous in those cases where phenol-formaldehyderesins of the novolak type themselves are not entirelysatisfactory in molding compositions or various types of bonding agents. Compositions prepared from phenol-formaldehyderesins themselves exhibit unfavorable parameters with respectto heat conductivity,thermal stability,dielectric and anti-fraction properties,viscosity and other chemical andphysicomechanical properties,as do the resins,moldingcompositions or molded articles prepared from them. According to one method of modification,6-caprolactamis added to novolak,dehydrated under vacuum at a temperatureof about 150℃. The mixture is kept at this temperature forabout 1 hour so that the required reaction of the componentsoccurs. During this period the properties of the basicresin change substantially. If high-molecular polyamide isused for modification,it is added directly and condensationof phenol and formaldehyde is carried out in its presence.Polyamide then reacts in the next phase with the phenol-formaldehyde product at temperatures of 100 to 180℃ in thepresence of an acid catalyst. Generally,l to 3 mol ofphenol with l to 2.5 mol of formaldehyde are used for oneamino group. It has now been found that the properties of phenol-formaldehyde resins(novolaks)can be favorably influencedby modification according to the invention in that 0.1 to 100 wt%,preferably 1.0 to 60 wt,of a mixture of 6-caprolactamand its cyclic and linear oligomers(referred to phenol)areadded to the reaction mixture of phenol with formaldehyde, Page 3 during which the mixture of oligomers of 6-caprolactam isadded to the reaction mixture during stabilization or afterstabilization with tertiary amines,their mixtures or theirmixtures with alkalis. This enables us to dehydrate thereaction mixture without using a vacuum up to unusually highfinal temperatures of the reaction mixture(200℃ and higher). A mixture of 6-caprolactam and its cyclic and linearoligomers(a product obtained by evaporating an aqueousextract of polyamide-6 after hydrolytic polymerization of6-caprolactam or a distillate from vacuum demonomerization ofan equilibrium polymerizate)can be successfully used formodification,added to the reaction mixture at any stage ofpreparation of the stabilized novolak before its finaldehydration. Another advantage of this new process,during whichstabilized phenol-formaldehyde resins are obtained,modifiedwith a mixture of 6-caprolactam and its oligomers,is the factthat a molar excess of formaldehyde can be used. Dehydrationof the reaction mixture without a vacuum leads to considerablesimplification of the process technology and apparatus andmodification with caprolactam oligomers doe

FAQs

What reaction is used to prepare the novolak phenol-formaldehyde resins?

Phenols are condensed with formaldehyde in the presence of acid catalysts, with stabilization using tertiary amines during dehydration.

How does the invention modify novolak resins to improve performance?

It adds 6-caprolactam and its cyclic and linear oligomers (and mixtures referred to as phenol) to the phenol-formaldehyde reaction mixture during or after stabilization.

What is the key process advantage regarding dehydration?

Dehydration can proceed without using a vacuum up to unusually high final temperatures (200℃ and higher), simplifying equipment and process technology.

Sep 21, 2026

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