US3142532A - Method of making polyvinyl alcohol fibers - Google Patents

Description

United States Patent M Japan No Drawing. Filed May 26, 1960, Ser. No. 31,824 Claims priority, application Japan May 26, 1959 4 Claims. (Cl. 8115.5)

This invention relates to the manufacture of polyvinyl alcoholic derivatives and to the formation of fibers from a spinning solution containing said derivatives.

As described in US. patent application Ser. No. 856,334, filed December 1, 1959, now US. Patent No. 3,007,228, the dyeability of polyvinyl alcohol fibers can be markedly increased by spinning the fibers from a mixture of an emulsified polymer formed from basic monomers and a water solution of polyvinyl alcohol. When fibers spun from such a mixture are subjected to benzalization, which has the effect of significantly improving the hot-water resistance and the elasticity of polyvinyl alcohol, fibers can be obtained which have excellent elastic recovery and dyeability without showing any significant drop in dye-absorption. This is substantially different from the results obtained by mixed spinning of watersoluble polymers containing basic nitrogen as heretofore practiced.

It is an object of this invention to provide a novel process for producing fibers of polyvinyl alcohol having high hot water-resistance, high heat-resistance and desirable mechanical properties similar to those of fibers produced solely from polyvinyl alcohol, yet characterized by a particularly high dyeability.

In accordance with this invention, spinning of fibers is elfected from a spinning fluid prepared by dispersing in a water solution of polyvinyl alcohol an emulsion or fine powder of a water-insoluble polyvinyl alcohol derivative obtained by etherification of polyvinyl alcohol with an epoxy compound containing basic nitrogen, ethyleneimine, or its derivatives, combined with acetalization with an aldehyde containing no basic nitrogen.

We have previously prepared emulsions or fine powders of a water-insoluble polyvinyl alcoholic derivative produced by acetalization with aldehydes containing basic nitrogen, and by acetalization with aldehydes containing no basic nitrogen, the second reaction being carried out simultaneously with prior to, or after the first reaction, depending upon the circumstances. The emulsions or fine powders obtained in this way were dispersed in an aqueous solution of polyvinyl alcohol and mixed spinning was effected from this mixed solution. It was found that the fibers produced by spinning with this mixed solution could be substantially improved in their dyeing characteristics with respect to acid and direct dyes not only when benzaldehyde was used for the treatment to make the fibers insoluble after they were treated with heat, but when formaldehyde was employed for such treatment.

As the result of research subsequently performed, we have discovered that when emulsions or fine powders of a water-insoluble polyvinyl alcohol derivative produced by aminoetherification using an epoxy compound or ethyleneimine, or its derivatives, as the compound containing basic nitrogen, in combination with acetalization by means of an aldehyde containing no basic nitrogen, which may be effected prior to or after aminoetherification. When the emulsions are dispersed in an aqueous solution of a polyvinyl alcohol to form a mixed spinning solution, and when the fibers spun from this solution are 3,142,532 Patented July 28, 1954 treated with heat and are subsequently subjected to acetalization in accordance with conventional practice, the improvement of the dyeing properties of the fibers is entirely satisfactory and the same results are obtainable when the aldehyde used for acetalization is benzaldehyde.

It will be understood that the particle diameter of the fine powders made by the method of this invention should be within a range suitable for mixed spinning. For this reason, emulsions or the fine powders having a diameter of less than 30 are suitably used. Fine powders having a suitable diameter are readily prepared by the process of this invention. Furthermore, the quantity of basic nitrogen in the finely-divided water-insoluble polyvinyl alcohol derivative should be more than 0.2%, and it is advantageous to use the polymer containing basic nitrogen in a proportion in relation to the polyvinyl alcohol such that the quantity of basic nitrogen is ODS-2.0% based on the polyvinyl alcohol. The fibers spun from the spinning solution produced by the method of this invention exhibit a substantial improvement in dyeing characteristics with respect to direct cotton dyes and with respect to acid woolen dyes, and yet any reduction of hot water-resistant, heat-resistant, or mechanical properties is negligible.

When eifecting the acetalization step to produce the emulsions or the fine powders suitable for the purposes of this invention,.it is generally desirable to do so under high speed agitation of the mixture and it is preferable to add any of the various known surface active agents or protective colloids to the solution. As surface active agents, various anionic, non-ionic, and cationic surface active agents are suitably used, but inasmuch as an anionic surface active agent may occasionally tend to coagulate solid particles by forming a bond with basic nitrogen, it is preferred to use a non-ionic surface active agent such as polyoxyethylenedodecyl ether, or a cationic surface active agent such as dodecyltrimethylammonium chloride. As protective colloids, compounds such as water-soluble starch, partially aminoacetalized polyvinyl alcohol, polyvinylpyrrolidone, and the like are suitably used.

To form a stable dispersion of the above-described solid polymer particles in a water solution of polyvinyl alcohol, various procedures may be employed. Thus when the polyvinyl alcohol derivative is in the form of an emulsion, the emulsion may be directly mixed with a water solution of polyvinyl alcohol, or it may be mixed with polyvinyl alcohol powder and water may then be added to dissolve the powder. Alternatively, the emulsion may be heated, and polyvinyl alcohol powder or moist polyvinyl alcohol powder may be slowly added and dissolved in the emulsion. When the polyvinyl alcohol derivative particles are in the form of a fine powder, the powder particles may be mixed with polyvinyl alcohol powder and water added to dissolve the powder mixture or the polyvinyl alcohol derivative particles may be mixed with a small amount of Water or a water solution of polyvinyl alcohol, and the paste of fine powder thus obtained may be mixed with polyvinyl alcohol. It will be understood, however, that various other procedures may be used.

It is possible to carry out spinning by means of the spinning fluid prepared by dispersing an emulsion or a fine powder of the polyvinyl alcohol derivatives with polyvinyl alcohol by the method of this invention, with the addition of various types of water-soluble polymers such as soluble starch, polyvinylpyrrolidone, aminoacetalized polyvinyl alcohol, various kinds of pigments such as titanium oxide, and acids, alkalis, and salts such as sodium sulfate, and the like. Accordingly, it is possible to simul taneously effect improvements in the transparency and in the form of the cross-section of the fibers, particularly when the fibers are formed by wet spinning.

The fiber spun by the method of this invention may be subjected to thermal elongation, i.e. hot-stretching, heat-treatment and insolubilization treatments in the same manner as fibers formed solely from ordinary polyvinyl alcohol. For effecting insolubilization treatments there may be employed acetalization by means of aldehydes such as formaldehyde, acetaldehyde, chloracetaldehyde, butylaldehyde, nonylaldehyde, benzaldehyde, monochlorbenzaldehyde, l-naphthaldehyde, glyoxal, malonaldehyde, glutaraldehyde, terephthalaldehyde, and the like. The fibers may also be subjected to treatments with inorganic reagents such as titanation, and chromination. Various other known insolubilization treatments may also be employed.

Compounds containing the basic nitrogen suitable for use in accordance with the method of this invention include epoxy compounds containing basic nitrogen which may be formed by the reaction of epichlorohydrin with any alkyl or cycloalkyl secondary amine such as dimethylamine, diethylamine, dibutylamine, didodecylamine, dihexylamine, chlorohexylamine, methyl-butylamine, and methyl-ethylamine, and the like, ethyleneimine, any of the derivatives of ethyleneimine containing the ethyleneimine ring such as those formed by the reaction of ethyleneimine with melamine, and the like, all of which form an ether linkage by reaction with the hydroxyl group of the polyvinyl alcohol.

Aldehydes suitably used in the method of this invention, are any of the aliphatic or aromatic or aralkyl aldehydes such as formaldehyde, acetalaldehyde, propionaldehyde, butylaldehyde, 2-ethyl-hexylaldehyde, nonylaldehyde, naphthalaldehyde, salicylaldehyde, benzaldehyde, trimethyl-tetrahydro benzaldehyde, and cinnamaldehyde, and like alkyl, aromatic and aralkyl aldehydes or their acetals.

The invention will be further understood from the following specific examples of practical application. However, it will be understood that these examples are not to be construed as limiting the scope of the present invention in any manner. In these examples, all parts are by weight, unless otherwise indicated.

Example 1 An aqueous solution containing 4% polyvinyl alcohol having an average degree of polymerization of 1000, 2% formaldehyde and 50% sulphuric acid was allowed to react at a temperature of 50 C. for a period of 60 minutes with agitation at the rate of more than 1000 r.p.m. To this solution was then gradually added a 1% aqueous solution of a dispersing agent in an amount equal to the volume of the initial quantity. There was thus produced, in finely-divided form, a polyvinyl alcohol derivative having a 65% degree of acetalization and a particle diameter of 2-3 r. The finely-divided particles were collected by filtration and washed with water thoroughly to remove any free acid and aldehyde.

Three grams of these formalized polyvinyl alcohol particles were mixed with 1.2 g. of l-diethylamine-2,3-epoxy propane. The mixture was subjected to the reaction at a temperature of 130 C. for a period of 3 hours in a pressure-proof container. After the reaction was completed, the resultant product was washed with hot water (60 C.) three times. The particle diameters of the powder obtained were 1-3/1. and the product had a basic nitrogen content of 1.5%.

The fine powder was then mixed with polyvinyl alcohol in the amount of 10% of the powder based on the polyvinyl alcohol. The mixture was dissolved by the addition of water to form a spinning solution in accordance with the usual procedure in forming polyvinyl alcohol spinning solutions. The resultant solution was subjected to wet spinning in a coagulation bath of Glaubers salt. The spun fibers were drawn by 400% at a temperature of 235 C. for a period of 5 seconds. The fibers were then treated with heat at constant length at a temperature of 235 C. for a period of seconds. Some of the fibers treated in this way were subjected to formalization in an aqueous solution containing 5% formaldehyde, 15% sulphuric acid, and 15 Glaubers salt at a temperature of 70 C. for a period of 2 hours. The remaining fibers were subjected to benzalization in an aqueous solution containing 2% benzaldehyde, 15% sulphuric acid, and 40% methanol at a temperature of 60 C. for a period of 2 hours. The fibers (1) treated with formaldehyde were 41.5% acetalized and the fibers (2) treated with benzaldehyde were 31.0% acetalized.

All of the thus-treated fibers were dyed in a dye bath (ratio of bath 1:100) containing 3% acid scarlet, 4% an acid dye and 3% sulphuric acid (all percentages based on the weight of the fibers) at a temperature of C. for a period of 60 minutes. Both fibers (l) and (2) satisfactorily absorbed the dye, and no loss in their dyeing properties was observed when the fibers were dyed after heat treatment. Moreover, the presence of dyed fine powders was found when the dyed fibers were observed by means of an optical miscroscope.

Example 2 Ten grams of polyvinyl alcohol and 5 g. of ethyleneimine were mixed, and the mixture was allowed to react in a pressure-proof container at a temperature of C. for a period of 4 hours. The derivative of the polyvinyl alcohol formed by this reaction was washed with methanol 3 times. This derivative, which was an aminoetherified polyvinyl alcohol had a basic nitrogen content of 1.0%.

An aqueous solution containing 4% of this aminoetherified polyvinyl alcohol, 2% formaldehyde and 50% sulphuric acid was subsequently reacted at a temperature of 50 C. for a period of 1 hour. To the resultant solution there was then added an equal volume of an aqueous solution containing 1% of a surface active agent. The surface active agent solution was gradually added drop wise while the polyvinyl alcohol solution was agitated at the rate of more than 1000 r.p.m. at a temperature of 40 C. By this process, fine water-insoluble particles having a 70% degree of acetalization and containing basic nitrogen were obtained. These particles were filtered and washed and the washed particles were formed into an aqueous emulsion.

The fine water-insoluble emulsified particles were then mixed with a polyvinyl alcohol in the proportion of 8% based on the polyvinyl alcohol and a spinning solution with a concentration of 35% was prepared. The spinning solution was extruded into air in accordance with the conventional dry-spinning process.

The resultant fibers were drawn at a temperature of 220 C. with a drawing ratio of 500% and they were then shrunk or relaxed at a temperature of 225 C. by 20%. The fibers were acetalized by the procedure described in Example 1 and the fibers were then dyed with an acid dye. Both the formalized and the benzalized fibers exhibited excellent dyeing properties, and yet no adverse effect on the physical properties of the benzalized fibers was observed, as shown in the following table wherein these fibers are compared with conventional polyvinyl alcohol fibers containing no basic nitrogen.

Furthermore, when the fibers made by the process of this invention were treated at a temperature of 235 C. for a period of 30 minutes, no coloring of the fibers was observed and the degree of their whiteness was more than 95.

Example 3 When an aqueous solution containing 3% polyvinyl alcohol having an average degree of polymerization of 1300, 2% formaldehyde, and 20% sulphuric acid was reacted at a temperature of 50 C. for a period of 120 minutes under agitation of more than 1000 r.p.m., fine particles of formalized polyvinyl alcohol were formed. The diameters of these particles were of the order of 5p, and the degree of acetalization was 70%. The particles were filtered and washed, and they were then dried for a period of 20 hours in air.

Ten grams of these fine particles of the polymer obtained were mixed with 5 g. of ethyleneimine and the resultant mixture was reacted in a pressure-proof container at a temperature of 110 C. for a period of 3 hours. The quantity of basic nitrogen in the fine particles after this reaction was 1.4%.

These fine particles were mixed with a 1% aqueous solution of a surface-active agent to form a emulsion. The emulsion was spun and the resultant fibers were heattreated and acetalized as described in Example 1. The resultant fibers were then dyed with Acid Scarlet 31R, and the dyeing properties of the fibers after acetalization were found to be good.

The surface-active or dispersing agents or dispersants and protective colloids which are suitably employed are, in addition to those mentioned above, any of the many dispersing agents and protective colloids known to those skilled in the art of making emulsions or dispersions of polymers. In the foregoing examples, for instance, polyoxyethylenedodecyl ether is suitably used as the dispersant or surface-active agent.

It will therefore be understood that, unless otherwise indicated, conventional operations and conventional apparatus are employed in carrying out the process of this invention including conventional mixing and emulsifying units. Similarly, conventional dyeing techniques and apparatus are suitably employed upon the fibers produced by the process of this invention. The conditions and the relative relationships set forth in the examples are those preferred in carrying out the process of the invention but it Will be understood that other conditions and relationships may be used within the scope of the invention.

The spinning fluids produced in accordance with the present invention are particularly suitable for the spinning of fibers in accordance with known processes used in the spinning of polyvinyl alcohol and polyvinyl alcohol derivatives, particularly the so-called wet-spinning techniquesas described, for example, in Cline et al. US. Patent 2,610,360 and Osugi et al. Patent No. 2,906,594. An especially preferred spinning technique is described in copending application Serial No. 336,166 of Tomonari et al., filed February 10, 1953, now U.S. Patent No. 2,988,802.

After formation of the fibers by wet spinning the filaments can be further treated by stretching, heat treating, acetalization, and the like to produce fibers with desirable and outstanding properties, using known techniques as described in said patents.-

It will also be understood that various changes and modifications in addition to those indicated above may be made in the embodiments herein described Without departing from the scope of the invention as defined in the appended claims. It is intended, therefore, that all matter contained in the foregoing description shall be interpreted as illustrative only and not as limitative of the invention.

We claim:

1. A process of producing fibers of polyvinyl alcohol of improved properties which comprises adding to an aqueous solution of polyvinyl alcohol, water-insoluble derivatives of polyvinyl alcohol in finely-divided form, mixing and distributing said derivatives in said solution and spinning said fibers from the resultant spinning solution, said derivatives containing more than 0.2% basic nitrogen and being the products resulting from reaction of polyvinyl alcohol with an aldehyde containing no basic nitrogen and with a member of the group consisting of ethylene-imine, the reaction product of ethylene-imine and melamine, and the reaction product of epichlorhydrin and an alkyl secondary amine, and acetalizing said fibers.

2. A polyvinyl alcohol spinning solution efiective to provide fibers of polyvinyl alcohol of improved prop erties formed by adding to an aqueous solution of polyvinyl alcohol, water-insoluble derivatives of polyvinyl alcohol in finely-divided form, and mixing and distributing said derivatives in said solution, said derivatives containing more than 0.2% basic nitrogen and being the products resulting from reaction of polyvinyl alcohol with an aldehyde containing no basic nitrogen and with a member of the group consisting of ethylene imine, the reaction product of ethylene-imine and melamine, and the reaction product of epichlorhydrin and an alkyl secondary amine.

3. A process of producing fibers of polyvinyl alcohol of improved properties which comprises adding to an aqueous solution of polyvinyl alcohol, water-insoluble derivatives of polyvinyl alcohol in finely divided form, mixing and distributing said derivatives in said solution, and spinning said fibers from the resultant spinning solution, said derivatives containing more than 0 .2% basic nitrogen and being the products resulting from reaction of polyvinyl alcohol with an aldehyde containing no basic nitrogen and with the reaction product of epichlorhydrin and an alkyl secondary amine and acetalizing said fibers.

4. A process of producing fibers of polyvinyl alcohol of improved properties which comprises adding to an aqueous solution of polyvinyl alcohol, water-insoluble derivatives of polyvinyl alcohol in finely divided form, mixing and distributing said derivatives in said solution, and spinning said fibers from the resultant spinning solution, said derivatives containing more than 0 .2% basic nitrogen and being the products resulting from reaction of polyvinyl alcohol with an aldehyde containing no basic nitrogen and with ethylene imine, and acetalizing said fibers.

References Cited in the file of this patent UNITED STATES PATENTS 2,296,225 Ulrich Sept. 15, 1942 2,341,413 Pense et al. Feb. 8, 1944 2,906,594 Osugi et al. Sept. 29, 1959

Claims (1)

1. A PROCESS OF PRODUCING FIBERS OF POLYVINYL ALCOHOL OF IMPROVED PROPERTIES WHICH COMPRISES ADDING TO AN AQUEOUS SOLUTION OF POLYVINYL ALCOHOL, WATER-INSOLUBLE DERIVATIVES OF POLYVINYL ALCOHOL IN FINELY-DIVIDED FORM, MIXING AND DISTRIBUTING SAID DERIVATIVES IN SAID SOLUTION AND SPINNING SAID FIBERS FROM THE RESULTANT SPINNING SOLUTION, SAID DERIVATIVES CONTAINING MORE THAN 0.2% BASIC NITROGEN AND BEING THE PRODUCTS RESULTING FROM REACTION OF POLYVINYL ALCOHOL WITH AN ALDEHYDE CONTAINING NO BASIC NITROGEN AND WITH A MEMBER OF THE GROUP CONSISTING OF ETHYLENE-IMINE, THE REACTION PRODUCT OF ETHYLENE-IMINE AND MELAMINE, AND THE REACTION PRODUCT OF EPICHLORHYDRIN AND AN ALKYL SECONDARY AMINE, AND ACETALIZING SAID FIBERS.