DE974333C - Process for the production of cellulose hydrate threads with improved bonding ability with rubber - Google Patents

Description

Process for the production of cellulose hydrate filaments with improved Bondability with rubber It is known that certain resinous compounds have the property of improving the adhesion of C.ellulose hydrate threads with rubber. British patent specification 477380 explains the treatment of tire cords with aqueous solutions or dispersions of heat-setting, aldehyde resin-forming Substances such as phenolic resins. Examples are resorcinol-formaldehyde condensation products specified.

According to British patent specification 582 210, cellulose hydrate filaments are used Made with a resorcinol-formaldehyde resin that hardens in the heat. This is done by mixing a precondensed resin into a viscose such as that used for spinning is done. This process can only be connected by very skilled engineers with a very precise control, technically carried out throughout the procedure. The difficulty lies in the inherent lack of stability of the Resin both on the resin itself and when it comes into contact with viscose. When the resin-viscous mixture is formed, gels of the foregoing will inevitably be formed coagulated Resin, and the spinning conditions are thereby unfavorable influenced, e.g. B. by jumping the candle filter or clogging the nozzle holes. Despite very precise control, there were many breakdowns during spinning. In In this case, the whole unit must be cleaned again.

Another difficulty is that when using a Viscose resin solution a whole unit of a viscose apparatus can be provided must and can only be used for resin-spun threads. The type of resin according to the British Patent 582 210 cannot be spun by injection like in the present invention, since its lifetime at the required concentration is far too short for injections. One advantage of an injector system is that the Injector unit can be used for each machine as required and, if the The injector is not in use, the machine for the standard viscous spinning process is available.

The purpose of the invention is to provide such precise regulations in the spinning process to make dispensable, namely through the use of certain incompletely condensed Resorcinol-formaldehyde resin solutions of sufficient shelf life for technical purposes.

The resins used in the practice of the invention differ differ essentially from the general type of a heat-setting resin, such as it is covered by British patent specification 582 210 by the fact that that the proportion of sodium hydroxide is significantly increased over the amount, which is normally used for catalytic processes. With the present Invention, the molecular ratio of sodium hydroxide is never below the molecular one Proportion of resorcinol, and it is preferably at least 12 times the molecular Amount of resorcinol.

According to the invention is a method for making viscose threads with an improved adhesion to rubber, in which the viscose in a nozzle submerged in an aqueous precipitation bath passes and into the viscose, briefly before it enters the spinning machine, an aqueous NaOH solution of an incomplete introduces condensed, heat-hardening resorcinol-formaldehyde resin, thereby ~ characterized that the molecular ratio of resorcinol to formaldehyde I: I, 3 to 3.5 and the molecular ratio of resorcinol to the NaOH of I: 1.0 to 3.5 and preferably between 1: 1.5 to 3.5.

In the invention, the method for introducing a compound carried out in the spinning solution as indicated in the patent specification 640 96I is.

The proportion of resin in the solution is preferably 5 up to 15 percent by weight. The amount to be used depends on the weight of the resin that should be present in the finished thread. 0.5 to 3 percent by weight Resin, calculated on the dry weight of the thread, is usually sufficient.

The invention is based on the observation that the specified resin solutions are stable enough to be able to use them as injection solutions in the continuous or discontinuous production of viscose threads. The solutions given generally have an effective life of 24 hours at 150. The stability of such solutions can be illustrated by way of example by means of experiments, the results of which are graphically shown in the drawing. The tests were carried out in all cases with technically high quality resorcinol and sodium hydroxide and a technical 37% solution of formaldehyde. Aqueous solutions containing both resorcinol and formaldehyde were prepared, and the resulting composition of this solution in terms of resorcinol and formaldehyde is given in the following table: Curve no. Resorcinol formaldehyde molecular in the resorcinol formaldehyde ratio of graphic weight- weight- formaldehyde Representation of percent I percent to resorcinol 1 6.74 2.76 1.5 II 9.0 3.68 1.5 III 8.64 4.7I 2.0 IV 8.20 5.60 2.5 V 7.8I 6.38 3.0 VI 7.8I 7.66 3.5 Various amounts of sodium hydroxide were then added to the solutions and in each case the time until gel formation was determined, the solutions being kept at 25 ° throughout.

From the graph it can be seen that when the molecular ratio of caustic soda to resorcinol is approximately 1.0: 1, the stability of the solutions is significantly better than the solutions with a molecular ratio below about 1.0: 1.

It has also been found that when the feed lines to the injection pump consist of iron, certain resin solutions show a pronounced tendency to use Viscose will form gels at ordinary temperature when in contact with iron come. It was further found that at a molecular ratio of sodium hydroxide to resorcinol from 1.5 to 3.5: I the tendency of the resin solution to form gel, practically is excluded, while solutions outside this range are usually after 4 Hours of contact between the viscose and the iron flake out as a gel.

As a result, it is provided according to the invention that when a press-fit pump consists of non-ferrous alloy, the molecular ratio of sodium hydroxide to Resorcinol I, 0 to 3.5: should be I, but if it consists of iron, 1.5 to 3.5 : 1.

The threads according to the invention can be used in the manufacture of tires and similar items made of synthetic or natural Types of rubber exist, such as. B. synthetic rubber, which by polymerization of butadiene with other polymerizable compounds of styrene or acrylonitrile are made.

It is an advantage of the invention that in viscose factories and storage no Resin impurities arise. Another advantage is that while threads are made with similar resin compounds treated, after spinning from viscose a stiff and hard handle had, the filaments of the invention are flexible, and this flexibility facilitates further processing, such as B. twisting in the manufacture of cords.

In the following examples, parts and percentages are parts by weight and weight percentages.

Example I An aqueous alkaline resin solution was obtained by dissolving it of resorcinol in an aqueous solution of sodium hydroxide and subsequent addition of formaldehyde (commercially available formalin solution) with a content of approximately 37 01o formaldehyde produced. During the addition of the formaldehyde solution, the Solution cooled to avoid excessive heating. The amounts used were chosen so that the composition of the aqueous solution q ° jO resorcinol, 3.68 01o Formaldehyde and 6.56 01o sodium hydroxide was what a molecular ratio of Formaldehyde to resorcinol of 1.5: I and a molecular ratio of sodium hydroxide corresponds to resorcinol of 2.0: 1. This solution was left to stand at 200 for 8 hours and then, as indicated in the patent specification 640 96I, introduced into a ripe viscose, which contained 7.4% cellulose and 6.0% sodium hydroxide. The resin-viscose mixture was spun at 50 in an aqueous bath, the 9.5% sulfuric acid, 20% sodium sulfate and contained 4 "10 zinc sulfate. The spun thread was then kept at a temperature 95 "stretched in a 1.5% sulfuric acid bath and resulted in a thread higher Strength of 1180 den and 500 single threads. The thread became free of acid and other impurities washed and dried.

However, it was not subjected to an alkaline desulfurization treatment. The injection amount of the aqueous alkaline resin solution into the viscose was I. Part resin solution to 99 parts viscose, which is about 1.5% resin calculated on that Dry weight of the thread. The thread was twisted into cords as follows. The twist of the thread was increased to 13 turns to 2.54 cm, and then it was two such threads are twisted in opposite directions until a thread of 11 Twists to one inch was obtained. The adhesion of these cords to rubber was made evaluated by the “H” sample according to the method described in the AIC 99 report “Study of the MH test for evaiuating the adhesive properties of tire cord in natural and GRS rubbers ”edited by W. James Lyons, Mary L. Nelson, and Carl M. Conrad by the United States Department of Agriculture, October 1945.

The tension that is exerted on the cords according to the example had to was 4.53 kg, while it was 3.05 kg for untreated viscose threads.

Example 2 An aqueous alkaline resin solution was made as in ii, Example I manufactured. The amounts used were such that the solution was 9.0% resorcinol, 3,200/0 Formaldehyde and 3.27010 sodium hydroxide, according to the molecular ratio from formaldehyde to resorcinol of 1.3: 1 and from caustic soda to resorcinol of I: I. The solution was left to stand at 20 ° for 72 hours before turning into a ripe viscose was injected, which contained 7.4 01o cellulose and 6.5 ° lo sodium hydroxide. the Viscose was then spun as treated in Example I to give a thread of 1180 den and 500 single threads. Injection of aqueous alkaline resin solution in the viscose was 1 part resin solution to 99 parts viscose, which is about 1.450 /, Resin, calculated on the dry weight of the thread. The thread was from Washed free of impurities, dried and applied to that described in Example 1 Twisted in cords. The bond of the cords to the rubber was as in Example I described, evaluated. The train, which on the manufactured according to the example Cords had to be exercised was 4 kg versus 2.98 kg for the untreated viscose.

Example 3 An aqueous alkaline resin solution was obtained as in Example I prepared, and the amounts used were such that the solution was 3.91% resorcinol, Contained 3.73% formaldehyde and 4.97% sodium hydroxide, corresponding to a molecular ratio of formaldehyde to resorcinol from 3.5: I and from sodium hydroxide to resorcinol from 3.5: I. The solution was allowed to stand at 16 "for 24 hours before injection in a ripe viscose which contained 7.4% cellulose and 7.0% sodium hydroxide as described in Example 1. The viscose was then spun and, as described in Example 1, treated further and gave a thread of 1750 den and 750 single threads. The injection amount of the aqueous alkaline resin solution for Viscose was I part of resin solution to 134.5 parts of viscose, which is about 0.5 01o resin, calculated on the dry weight of the thread. The thread became free of Impurities washed, dried and corded as described in Example I twisted. The cord had a twist of 12 turns by 2.54 cm in the monofilament. Two such threads were twisted together until a twist of 12 turns to 2.54 cm was reached. The bond of these cords to rubber was evaluated as in Example I. The tension required for the cord made according to the example was 4.42 kg compared to the untreated cord of 3.54 kg.

Claims (1)

PATENT CLAIM: Process for the production of cellulose hydrate filaments with improved bondability with rubber by spinning a viscose through a nozzle submerged in an aqueous precipitation bath, whereby the spinning solution shortly before entering the spinning machine, an aqueous sodium hydroxide solution an incompletely condensed, heat-hardening resorcinol-formaldehyde resin is injected, characterized by the fact that the molecular ratio of resorcinol to formaldehyde I: I, 3 to 3.5 and the molecular ratio of resorcinol to sodium hydroxide as a condensing agent I: 1.0 to 3.5, preferably I: I, 5 to 3.5. Documents considered: British Patent No. 582 2I0; French patent specification no; 892 193.