Preparation method of ultrahigh molecular weight phenolic resin

Abstract

The invention discloses a preparation method of ultrahigh molecular weight phenolic resin. The preparation method comprises the following steps of: (1) weighing phenol and aldehyde in a molar ratio of 1: (0.8-1.0) respectively, and weighing acid in a mass ratio of the acid to the phenol of (0.5-4): 100; (2) mixing the phenol, partial aldehyde and partial acid, heating till boiling, and refluxing for 2 to 4 hours, wherein the partial aldehyde or the partial acid accounts for 75 to 95 percent of the total adding amount of the aldehyde or the acid; (3) heating and dehydrating the reactants of the step (2), cooling the reactants to the temperature of between 80 and 100 DEG C, adding the rest aldehyde and the rest acid, heating till boiling, and refluxing for 1 to 3 hours; and (4) detecting the melting viscosity of the reactants in the refluxing process of the step (3), adding alkali when the viscosity reaches 2,000 to 4,500MPa.s / 100 DEG C, regulating the pH value to be between 4 and 7, heating and dehydrating to obtain the ultrahigh molecular weight phenolic resin. The weight-average molecular weight of the prepared phenolic resin can reach 14,000 to 30,000, the softening point is 120 to 140 DEG C, and the molecular weight distribution is 13 to 19.

Description

technical field [0001] The invention relates to the technical field of preparation of phenolic resin, in particular to a preparation method of ultra-high molecular weight phenolic resin. Background technique [0002] Phenolic resin is the earliest industrialized synthetic resin in the world. It has a history of nearly 100 years. Because of its advantages such as easy availability of raw materials, low price of raw materials, simple production process and equipment, and more importantly, the excellent properties of phenolic resin itself Performance, has been widely used in various fields of daily life. Among them, due to the high temperature resistance of ultra-high molecular weight phenolic resin itself, it is widely used in high-end molding compounds, friction materials, abrasive abrasives, etc. [0003] Ultra-high molecular weight phenolic resin is a thermoplastic phenolic resin with a weight average molecular weight of about 15,000 and above. In the production of existin...

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Problems solved by technology

[0003] Ultra-high molecular weight phenolic resin is a thermoplastic phenolic resin with a weight average molecular weight of about 15,000 and above. In the production of existing ultra-high molecular weight phenolic resin, a relatively high ratio of raw materials is required, and it is difficult to control during the production process. It is easy to occur during the reaction process. Gel, no thermoplastic phenolic resin

[0004] Existing published patent CN1440990A discloses a preparation method of high molecular weight phenolic resin used for melt spinning. In this patent, transition metal oxide is used as catalyst, and the metal oxide remaining in the resin will affect the performance of phenolic resin. Electrical performance, and the production process uses a large amount of organic solvents, which increases the risk of operation and the difficulty of wastewater treatment to a certain extent