DE1179361B - Process for producing molded articles using phenol-formaldehyde resins - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 08 g

German class: 39 b -22/02

Number: 1179 361

File number: N 8029 IVc / 39 b

Filing date: November 14, 1953

Opening day: October 8, 1964

It is known that no noticeable hardening of a simple heat convertible material occurs below 100 ° C Phenol aldehyde resin. In practice, the hardening at a temperature will be of the order of magnitude carried out from 150 to 160 ° C. Each decrease in temperature by 10 ° C doubles the Hardening time.

It is possible to increase the cure temperature and time (or both) with such resins by adding stronger Reduce catalysts. Resorcinol and formaldehyde resins also have more favorable hardening conditions. The resorcinol-formaldehyde resins are unstable and harden in 3 to 6 hours to a "gel" state or until gelling. Furthermore, these make this as an admixture to the phenol-formaldehyde resin likewise unstable at room temperature, so that this depends on in an undesirably short time from the proportions of resorcinol formaldehyde and phenol formaldehyde in the mixture to the gel state harden seeks.

The advantages of mixing the resins in order to cure To improve the monohydric phenol-aldehyde resin are hereby largely called into question.

The usage time of felts or fabrics made with phenolaldehyde resin and additionally with resorcinaldehyde resin have been impregnated is undesirably short.

The subject matter of the invention is a method of production of molded articles made of fiber material impregnated with phenol-formaldehyde resins. The procedure is through characterized in that two phenol-formaldehyde resins are used as the impregnating agent and by impregnation brings together in the fibrous material, namely a thermosetting condensation product produced from a monohydric phenol and formaldehyde in a molar ratio of 1: 1 to 1: 1.5, and a condensation product, made from a polyhydric phenol and formaldehyde in a molar ratio of 1: 0.5 up to 1: 0.8, which is stable at normal temperature and the impregnated and shaped fiber material hardens by heat.

By the presence of z. B. Resorcinaldehyde resins ensure that when heated of the mixture to a hardening temperature above room temperature, hardening occurs more quickly.

Furthermore, because of the stability of the mixture at room temperature, the implementation of treatment operations, such as the impregnation of the fibers or similar felts or fabric components with the mixture or with its individual processes for producing molded articles
by means of phenol-formaldehyde resins

Applicant:

National Research Development Corporation,

London

Representative:

Dipl.-Ing. E. Schubert, patent attorney,

Siegen, Eiserner Str. 227

Named as inventor:

Leslie Nathan Phillips,

Farnborough, Hampshire (UK)

Claimed priority:
Great Britain November 15, 1952
(28 878)

Components and the placing of such impregnated components in the molds for the purpose of deformation, facilitated, the impregnating resin impregnation mixture faster and at a lower Temperature hardens.

The impregnation of the felts or fabrics with the phenol aldehyde resins can be done by spraying or brushing or brushing or dipping can be carried out as desired.

example

A number of felts that have been impregnated with a phenol-formaldehyde resin have been made according to the invention with a solution of 70 parts by volume of a stable resorcinol-formaldehyde resin syrup and 30 parts by volume of acetone impregnated, the impregnation by brushing or brushing the Solution was done on the felts, which were then piled on top of each other. Of the Pile [s. under a) in the following table] was then hardened using the vacuum forming process, d. H. by placing in a rubber container. Evacuate the container to the vacuum of 62.5 cm Hg, placing the evacuated container in an oven and heating to harden on a Temperature of 110 ° C for 1 hour while maintaining the vacuum.

For comparison purposes, two similar stacks of felts were prepared [see Sect. b) and c) of the following

«9 690/341

The following table], but not impregnated with the stable resorcinol formaldehyde resin, the stack b) being cured under the same conditions as stack a) and the stack) in the usual way for ¹ Iz hour at 160 ° C plus the time which was necessary to reach this temperature in order to complete the cure.

It should be noted that in case c) full curing at HO ⁰ C would require 16 hours and at 100 ° C 36 hours.

The following physical properties were obtained:

Elasticity Border train module strength a) Material A according to the invention 2.59-10 ⁶ psi 18000 p. S. i. b) Common material B 1.88 14,000 p. s. i. c) Common material C 2.40 19,000 p. s. i.

Claims (1)

Claim: Process for the production of molded articles from impregnated with phenol-formaldehyde resins Fiber material, characterized in that the impregnating agent used is two phenol-formaldehyde resins used and brought together by soaking in the fiber material, namely a thermosetting Condensation product made from a monohydric phenol and formaldehyde im Molar ratio 1: 1 to 1: 1.5, and a condensation product, made from a polyhydric phenol and formaldehyde in a molar ratio of 1: 0.5 to 1: 0.8, which is at ordinary temperature is stable, and the impregnated and shaped fiber material hardens by heat. Considered publications:
German Patent No. 906 753;
Austrian Patent No. 130,643;
British Patent No. 325 861. A priority document was displayed when the registration was announced.