DD205914B1

DD205914B1 - PROCESS FOR THE PRODUCTION OF NOVOLAKEN

Info

Publication number: DD205914B1
Application number: DD24197082A
Authority: DD
Inventors: Hannelore Hitzer; Paul Grzechnik; Holmar Nigrini; Otto Quast; Joerg-Dietmar Sauer
Original assignee: Sprela Werke Spremberg Veb
Priority date: 1982-07-27
Filing date: 1982-07-27
Publication date: 1986-03-12
Also published as: DD205914A1

Description

Dem technischen Gemisch von gesättigten Kohlenwasserstoffen, welches mindestens 70% aliphatisch gesättigte Kohlenwasserstoffe enthält, werden 0,01 bis 0,05% eines Tensids, bezogen auf die Masse des Endproduktes, zugemischt. Damit wird eine beständige homogene Verteilung des an sich nicht mit Novolaken mischbaren reinen aliphatisch gesättigten Kohlenwasserstoffs bzw. der technischen Gemische von gesättigten Kohlenwasserstoffen erreicht.The technical mixture of saturated hydrocarbons containing at least 70% of aliphatic saturated hydrocarbons, 0.01 to 0.05% of a surfactant, based on the mass of the final product, admixed. This achieves a stable, homogeneous distribution of the pure aliphatic saturated hydrocarbon which is not miscible with novolaks or of the technical mixtures of saturated hydrocarbons.

Weiterhin wird eine Verzögerung des Viskositätsanstiegs während der destillativen Aufarbeitung des Phenol-Formaldehyd-Kondensates und damit eine entscheidende Senkung der Destillationszeit erreicht, der sich aus einem niedrigen Vemetzungsgrad im Polykondensat nach dem erfindungsgemäßen Verfahren gegenüber den bekannten technischen Verfahren zur Herstellung von Novolaken erklärt.Furthermore, a delay of the viscosity increase during the workup by distillation of the phenol-formaldehyde condensate and thus a decisive reduction in the distillation time is achieved, which is explained by a low degree of crosslinking in the polycondensate by the novel process over the known technical processes for the production of novolacs.

Als vorteilhafte Nebenwirkung der erfindungsgemäßen Zusätze ist eine geringe Staubneigung beim Vermählen und bei der Applikation, die z. B. eine bessere Haftung des Novolak-Härtungsmittelpulvers an Textilfasern bewirkt, festzustellen. Der Monomergehalt an freiem Phenol der erfindungsgemäß hergestellten Novolake läßt sich zweckmäßig durch bekannte Methoden des Einblasens von Wasserdampf oder Inertgas in die heiße Novolak-Schmelze während der Destillation und/oder durch Waschen oder durch chemische Methoden senken.An advantageous side effect of the additives according to the invention is a low tendency to dust during grinding and in the application, the z. B. causes a better adhesion of the novolak curing agent powder to textile fibers, determine. The monomer content of free phenol of novolaks according to the invention can be conveniently reduced by known methods of blowing steam or inert gas into the hot novolak melt during distillation and / or by washing or by chemical methods.

Ausführungsbeispiele Beispiel 1:Exemplary embodiments Example 1

100 Gewichtsteile verflüssigtes Phenol werden mit 69,3 Gewichtsteilen 37%iger wäßriger Formaldehydlösung und 1,97 Gewichtsteilen Oxalsäure in einem Reaktionsgefäß unter Normaldruck bei Siedetemperatur 60 Minuten kondensiert.100 parts by weight of liquefied phenol are condensed with 69.3 parts by weight of 37% aqueous formaldehyde solution and 1.97 parts by weight of oxalic acid in a reaction vessel under atmospheric pressure at a boiling point of 60 minutes.

Der Kondensationsgrad des Novolaks beträgt 3000 mPa/s bei einer Temperatur von 313 Kelvin. Anschließend wird die wäßrige Phase von der Harzphase abgetrennt und der im Reaktionsgefäß verbleibenden Harzphase 0,225 Gewichtsteile Paraffinöl, das mit 0,02 Gewichtsteilen Präwozell W-ON 33 emulgiert ist, zugesetzt. Das in der Harzphase noch vorhandene restliche Wasser wird destillativ entfernt und bei einer Produkttemperatur von 420 Kelvin mit dem Einblasen von Wasserdampf in die heiße Novolak-Schmelze begonnen. Diese Operation wird solange unter Vakuum bei einer Produkttemperatur von 425 Kelvin durchgeführt, bis der freie Phenolgehalt des Novolaks 0,9% beträgt. Der Novolak wird dann aus dem Reaktionsapparat in eine Kühlvorrichtung abgelassen und in einer Mühle gemahlen. Das erhaltene Produkt weist eine geringe Siaubneigung und folgende Kennwerte auf:The degree of condensation of the novolak is 3000 mPa / s at a temperature of 313 Kelvin. Subsequently, the aqueous phase is separated from the resin phase and the resin phase remaining in the reaction vessel, 0.225 parts by weight of paraffin oil, which is emulsified with 0.02 parts by weight Präwozell W-ON 33 added. The remaining water remaining in the resin phase is removed by distillation and, at a product temperature of 420 Kelvin, injection of steam into the hot novolak melt is begun. This operation is carried out under vacuum at a product temperature of 425 Kelvin until the free phenol content of the novolak is 0.9%. The novolac is then discharged from the reactor into a cooler and ground in a mill. The product obtained has a low tendency to slide and the following characteristics:

Schmelzbereich (nach Thiele) 81/84⁰CMelting range (after Thiele) 81/84 ⁰ C

Viskosität der 50%igen äthanolischen Lösung 98,4 mPa.sViscosity of the 50% ethanolic solution 98.4 mPa.s

Gehaltan nichtflüchtigen AnteilenContent of non-volatile components

(Einwaage0,5;2hbei150°C) 99,0%(Weight 0.5, 2h at 150 ° C) 99.0%

B-Zeit mil 5 % HexamethylentetraminB time with 5% hexamethylenetetramine

und 1 % Salicylsäure 40 sand 1% salicylic acid 40 s

Fließstrecke bei 125 ⁰C (nach DIN 16 916/02) 59,5 mmFlow path at 125 ⁰ C (according to DIN 16 916/02) 59.5 mm

Example 2:

100 Gewichtsteile verflüssigtes Phenol werden mit 65,0 Gewichtsteilen 36,8%iger wäßriger Formaldehydlösung und 1,34 Gewichtsteilen Oxalsäure-Dihydrat in einem Reaktor unter Normaldruck bei Siedetemperatur 80 Minuten kondensiert. Der Formaldehydgehalt in der Wasserphase beträgt nach der Kondensation 1,3%. Anschließend wird die wäßrige Phase von der Harzphase abgetrennt und der im Reaktor verbleibenden Harzphase 0,25 Gewichtsteile Getriebeöl (Viskosität 11 ⁰E), das mit 0,015 Gewichtsteilen Präwozell W-ON 33 emulgiert ist, zugesetzt. Das in der Harzphase noch vorhandene restliche Wasser wird durch Destillation, zum Ende der Destillation unter vermindertem Druck bis 435 Kelvin entfernt und solange Wasserdampf in die heiße Novolak-Schmelze eingeblasen, bis der freie Phenolgehalt des Novolaks 0,5% beträgt.100 parts by weight of liquefied phenol are condensed with 65.0 parts by weight of 36.8% strength aqueous formaldehyde solution and 1.34 parts by weight of oxalic acid dihydrate in a reactor under atmospheric pressure at the boiling point for 80 minutes. The formaldehyde content in the water phase after the condensation is 1.3%. Subsequently, the aqueous phase is separated from the resin phase and the resin phase remaining in the reactor 0.25 parts by weight of gear oil (viscosity 11 ⁰ E), which is emulsified with 0.015 parts by weight Präwozell W-ON 33 added. The residual water remaining in the resin phase is removed by distillation at the end of the distillation under reduced pressure to 435 Kelvin and as long as water vapor is blown into the hot novolak melt until the free phenol content of the novolak is 0.5%.

Der Novolak wird dann aus dem Reaktor in eine Kühlvorrichtung abgelassen und in einer Mühle gemahlen. Das Produkt weist eine äußerst geringe Staubneigung und folgende Kennwerte auf:The novolac is then discharged from the reactor to a cooler and ground in a mill. The product has a very low tendency to dust and the following characteristics:

Schmelzbereich (nach Boetius) 78/81⁰CMelting range (according to Boetius) 78/81 ⁰ C

Viskosität der 50%igen äthanolischen Lösung 121,3 mPa.sViscosity of the 50% ethanolic solution 121.3 mPa.s

Gehalt an nichtflüchtigen AnteilenNonvolatile content

(Einwaage 0,5 g; 2 h bei 150⁰C 99,4%(Weight 0.5 g, 2 h at 150 ^° C. 99.4%)

B-Zeit mit 5 % HexamethylentetraminB time with 5% hexamethylenetetramine

und5%Anilin 50sand 5% aniline 50s

Fließstrecke bei 125 ⁰C (nach DIN 16 916/02) 44,5 mmFlow path at 125 ⁰ C (according to DIN 16 916/02) 44.5 mm

Claims

Invention claim:

Process for the preparation of novolacs by polycondensation of phenols with formaldehyde in a molar ratio of 1: 0.5 to 1.0 using acidic catalysts at a temperature of 353 to 373 Kelvin, wherein after reaching a defined degree of polycondensation, the resulting aqueous phase separated from the resin phase and the resin phase is subsequently subjected to a distillation, characterized in that during the polycondensation 0.1 to 0.5% of a technical mixture of saturated hydrocarbons containing at least 70% aliphatic saturated hydrocarbons having at least 15 carbon atoms, preferably 18 to 35 C. -Atomen, and 0.01 to 0.05% of a surfactant, each based on the mass of the final product are added, wherein the technical mixture of saturated hydrocarbons and the surfactant are mixed before the Zugae.

Field of application of the invention

The invention relates to a process for the preparation of phenol-formaldehyde resins of the novolak type, which can find appropriate use as a binder for the production of insulating and insulating materials, brake and friction linings, foundry molds and cores and molding compounds.

Characteristic of the known technical solutions

The preparation of phenol-formaldehyde resins of the novolac type is carried out by known methods by polycondensation of phenols with formaldehyde in a molar ratio of 1: <1 in an acidic medium. They represent mixtures of predominantly chain-shaped, methylene-linked polyphenols which contain no reactive hydroxymethyl groups. In contrast to resoles, novolaks have a higher degree of polycondensation, which is reflected in relatively high molar masses of about 1000. The novolaks show no self-curing properties, they can enter into crosslinking reactions only by adding curing agents.

It is known that with high reactivity of the novolak curing agent mixture only a low flow behavior at curing temperatures of 398 Kelvin and is observed, which is a significant disadvantage for many applications. It is also known that free phenol, which is present as unreacted monomer in the novolak, improves the flow and cure behavior of novolak curing agent blends.

Are known methods for the preparation of novolacs, in which by modifying the novolaks with different chemical compounds, eg. For example, carboxylic acids, carboxylic anhydrides, certain quality properties are to be achieved. In DE-OS 2811 956 a process for the modification of novolaks is described in which the inventive modification of the novolak with unsaturated polycarboxylic acids can also be carried out in the presence of unsaturated oils and / or their corresponding unsaturated fatty acids. Linseed oil, wood oil, soybean oil, dehydrated castor oil or the underlying fatty acids are mentioned as suitable substances in the same patent specification, the weight ratio between novolak and fatty oils or oil fatty acids being 5 to 300, preferably 10 to 200. Although the separation of the aqueous phase, a reduction in the time required for the work-up by distillation of the phenol-formaldehyde condensate, no significant increase in productivity and reduction of energy consumption can be achieved as with increasing removal by distillation of the water still in the resin phase, a strong increase in viscosity is recorded. This causes a deterioration of the heat transfer from the heating surfaces of the reactor to the polycondensate in the reactor.

Also known is a process for the preparation of modified PF novolacs in which up to 6% of a pure saturated or unsaturated fatty acid or of a natural or synthetic fatty acid mixture is added to the resin phase before or during the distillation (DD-WP 203731). The fatty acids or fatty acid mixtures have at least 6 carbon atoms. In contrast to the technical solutions described above, an improvement in the heat transfer from the heating surfaces of the reactor to the polycondensate in the reactor occurs. A disadvantage of the method according to DD-WP 203731 is the inhomogeneous distribution of the fatty acids or fatty acid mixtures in the PF novolac, which leads to quality defects during processing with fillers and / or reinforcing materials.

Object of the invention

The aim of the invention is the cost-effective production of modified novolaks, which have a uniform distribution of the modifier and thus a homogeneous structure. The novolaks produced according to the invention must, during processing, lead to high-quality products which have constant utility value properties.

Explanation of the essence of the invention

The object of the invention is the development of a technically easily manageable and economical method for the production of novolacs, wherein the novolaks are characterized by a low molecular weight structure and a lower monomer content of free phenol. In the method according to the invention a strong increase in viscosity of the polycondensate during distillative dehydration is to be avoided since high molecular weight novolacs do not have the desired utility value properties, such. B. good flow behavior with high reactivity na ^ h addition of conventional curing agent having. The object of the invention is to find a way of reducing the viscosity increase in order to shorten the distillation times.

Another object of the invention is the production of novolaks in which the modifying agents used are uniformly distributed. The uniform distribution must be maintained even during processing.

According to the invention, this object is achieved in that a method for the production of novolacs by polycondensation of phenols with formaldehyde in Molverhäitnis 1: 0.5 to 1.0 using acidic catalysts at a temperature of 353 to 374 Kelvin applies, where after reaching a defined Polykondensationsgrades the resulting aqueous phase separated from the resin phase and the resin phase is then subjected to a distillation.

0.1 to 0.5%, based on the mass of the end product, of a technical mixture of saturated hydrocarbons is added to the resin phase before or during the distillation.

It is possible to use both pure aliphatically saturated hydrocarbons and preferably also a technical mixture of saturated hydrocarbons which contains at least 70% of aliphatically saturated hydrocarbons, the saturated hydrocarbons containing at least 15 C atoms, preferably 18 to 35 C atoms. Particularly suitable are products obtained from coal or lignite coal tar or petroleum by distillation, work-up with selective solvents or dehydrogenation, such as. As mineral oils or refined products thereof.