DE1937985A1 - Process for the production of polyvinyl alcohol threads - Google Patents

Description

Process for the production of polyvinyl alcohol threads

¹ The invention relates to process for the preparation ^ in _'t' \ position of Polyvinylalkoholfäden, in particular a ^ \ A process for producing filaments of polyvinyl alcohol is abbreviated as PVA below, with one _of; The shape of the spinning opening corresponds exactly to the ring-shaped cross-section and has a homogeneous and compact structure, which continues to have excellent stretchability. . ... ■ - · ". ■ '''■*" :. ■ ^\ .- {For the production of hollow or transparent PVA * j threads eats it is known, an aqueous PVA solution containing a water-soluble boric acid · in an amount of: at most 1 Grew.-ji, based on PVA, to be spun in an aqueous coagulating bath, which predominantly contains sodium or ammonium sulfate and to an alkaline value of a pH value in the order of 8 to 9 with a low However, in this process, due to the fact that the boric acid compound content of the aqueous PVA solution was low and the pH of the aqueous coagulating bath was almost neutral, the solidification of the hair-spun threads was achieved in this process not only slowly, but also the threads obtained had no cross-section which actually took the form of the

009809/1046

Spinning opening corresponded, nor was dl · structure of bland · » sufficiently co-compact

The task of the invention therefore lies in "in" Process for the production of τοη PVA-iäden, which · dl · gate standing laohtelle does not exist, whereby the · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · the> acid connection and duroh use of a strongly alkali • ohen aqueous coagulating bath a is achieved

According to the experiments, the scope of the fire it was stated that if an aqueous PTA solution was used old a relatively large amount of a boric acid compound, for example "Ehr al · 1 bie 5 Oew .-?", In "In stark alkaline · aqueous coagulant bath, which · a large Contains an amount of an alkali metal oxide, is extruded, • in spiders due to the abnormally high speed of the Coagulation could not be achieved ·· Dl · · was allowed to be on the fact «urüokiufuhr, that dl · large amount the boric acid compound contained in the aqueous PTA solution a · Cross-linking reaction old the PYA under strong alkaline conditions. In view of these facts, it was established that it was necessary to achieve the goal Object according to the invention by spinning an aqueous PVA solution that is a relatively large amount which contains boric acid terbindvjig · is necessary, an aqueous Apply Koagullerbad, which consists of a large Amount of an alkali hydroxide (this is an important condition sur achievement of a compact structure and a cross-sectional shape exactly corresponding to the? ona of the spinning opening) lueamm with a large amount of sodium sulfate (this is an important condition for the achievement of a good spinnable belt) contains

0.09809 / 16 46

Thus, in accordance with the red-lying invention, FTA threads with a crown-shaped cross-section and a homogeneous and compact structure can be obtained, loaded in aqueous FFA solution with a concentration of 10 to 30 ow .- *, the pH of which is 3 bi «5 was set and dl · 1 ble 5 G * w.-jt» lied about FTA, a water-free boric acid blindness «nthlllt, au · ring- * furmlf« n nnnuffnungcn in «inwlSrie ·· Koagullvrbad Teraponzun vlri, weloh ·« 20 Let 160 g alkali hydrojqrd J · liter and 100 bit 18Of IatriuMulphat J · liter #ntnMlt and the pH value to 13 _t 5 to 14%. The dab ·! The threads received do not just soap an excuse- ■ • pays · Streokborkeit _v eoodern and auoh without any high inconvenience in any one of their £ l £ eneohaften in any one place «along the threads and continue to run an excellently rewarded balance.

The wltürife PVA-Löeußf alt an Eonienttrmtlon τοη 10 bia 30 0ew .- ^ _v the sub Terapinn "n geetiö of the invention is used * bien as roretthend carried out" 1 bia 5 Gew.-j (and preferably 2 to 3 Oew.- jt, betofen on FTA _{f of} a water-oilable doreiureyerbiudunf, and its pH value is still 3 to 5. the beaogen on PYA "Meng · on dieeen Boreäurererblndunf s less el" 1 part by weight f (is, iet the Koaguliergeeohwindlgkelt "u langeaa," o that infolgedeeeen an adhesion swieohen takes place the frieohgeeponnenen threads. If anderereelte the amount is larger ale 5 O * w .-fC iet, if the coagulation speed is low and consequently there is a "" tendency of the threads to attach directly to you.

009809/1646

K extrusion. The division of the pH value of the aqueous PTA-Lttsung is la usual Vela · duroh the addition of a small amount of a mineral acid, for example sehulphuric acid, Salea acid or nitric acid carried out, fall the pH value of the aqueous FTA solution is less than 3 carries »problems arise with regard to the corrosion of the equipment due to the use rs *! igen stubborn as well as the see due to the low Ko & gullergesohvlndigkelt resulting JUoh parts. On the other hand, if the pH If the value exceeds 5, the aqueous PTA solution becomes unstable and the spinnability is increased fast Kosgullergesohwindigkelt soles. Case dia PTA concentration of the PTA solution would be longer than 10 Oew.-ji is * 1st derail Kosgullersarkelt low and it is known only from lower threads Toughness can be obtained * while falling the PTA «consistency 30 0ew .-? I exceeds the Tiskoeitat au hooh becomes difficult and spinning becomes difficult FTA ion release of the heavy ITA resolution, 41 · sub Tersplnnsn of threads is used, is 14 to 20 oewe-jt.

Oeaäe the invention is a la Torsteheadea dealt with WäSrlge PTA solution at a tea temperature τοη 20 to 4OT according to the Uellohen PTA-SaisplasTerfahreB from ring-shaped, circular openings into an aqueous white coagulation hole 4 sponnen, which 20 ble 100 g alkali hydroxide each Liters and 100 ble 180 g latriuasulfatEach liter contains » the pH of which is adjusted to 13.5 p. 14. Badureh a swelling of the threads la väflrlgsa Koagullerbad is changed and threads old elnea riagfOralgea Quereohnitt and ▼ on noBogener and co-compact structure will cool down * If the concentration dee AlkaUhjdroiyde weaiger ale 20 g per liter, let the Coagullergeeafavinalgkeit

009809/1646

low, but the quality of the spun threads is not round, but rather flashes, if the concentration of the alkali hydroxide exceeds 100 g per liter *, there is an extreme decrease in spinning ability. The recommended concentration of the alkali hydroxide is 40 to 30 g / liter. Sodium hydroxide or potassium hydroxide, especially the first _f, are suitable as alkali hydroxide. If the sodium sulphate is used in an amount of clay less than 100 g / 1 liter, the spinning ability decreases and the pinning becomes either completely impossible or only possible if the splinting ability is considerably reduced. On the other hand, if the amount of sodium sulfate exceeds 180 g per liter, the rate of dehydration becomes too rapid, so that instead of the advantage of forming threads with an annular cross-section, there is a shortage and threads with a flat or elliptical cross-section are formed as in FIG the case «where the spinning is carried out by extruding the PVA solution into a customary aqueous coagulating material» which is predominantly composed of sodium sulfate or sodium carbonate * · The preferred concentration of sodium sulfate is 120 to 150 g per liter.

"pie spun in the aqueous coagulation bath according to the present process threads are then removed and after treatments wi · neutralization _t 'lines and subjected to heat treatment so that the thread will receive the various properties" di · il · must have for practical use. This post-treatment can be carried out in the usual way. The features of the present invention are "that an aqueous PVA solution of an ape" ifieoh "n Zuaaaaen-

009809/16 4 6

»Etsung and a specific pH value ·» in an aqueous

specific

Koagullerbad τοη spesiflecher Suaaoaeneetsunf Λΰϊα? PH value On the other hand, everyone can working conditions previously applied at HaSsplnnan τοη FITA and devices can be used without any modification.

The following examples and comparative examples serve to further explain the invention, without the Limit invention in any way

Examples 1 to 4 and comparative figures 1 to 3

Boric acid in the amount given in Table I. su an aqueous solution with 18 wt. s * PTA τοη a polymer i sat ionegrad τοη 1700 and a degree of saponification τοη 99 # 5 MoI- ^ sugesetst and resolved. The pH of this solution was then adjusted to the value given in Table I with a small amount of sulfuric acid. These aqueous PVA solution was made from annular 3pinning orifices in aqueous Xoagulierbäder τοη indicated in Table I. Compositions and pH values spun · The fresh-; spun threads were stretched with orphans 100 pounds and: then in a neutralizing bath "which contained 60 g of sulfuric acid per liter and 300 g of sodium sulfate per liter" was neutralized. This was followed by a treatment of the threads with a wet-heat stretching τοη 100 # »washing with water and dry warning stretching τοη 225 # an »so that threads The total stretching ratio obtained was 1200 ^> fraud. The properties of the threads obtained are also the same listed in Table I.

0 0 9 8 0 9/1646

Vereuohe- amount Mr. 3ore acid, beeo-, to on

PVA (wt .- *)

pH value aqueous

der ^: Zttaaaaei wäßri- latrlua gen FVA- hydroxyl

iui

Kigenohaf the threads old

• Sulphate

pH

Ee:

η 1200

) enier- Z saw!

UxIg- '

ΨΦ *

etttn-

speed
ffff · «-

(• c)

critical

■ eh *

Stretching

rerfeält-

ni

Vtrfl. 1

ov Beiep. 1

3
4th

0.5

6.5

1.5

2.P

2.0

3.0

7 6

4.3 4

O 80 20 80 40 80 40

400 150 150

150 150 100 100

7 14

13.7 14

14 14

4.01 3.5

4.02 3.15 2.45 3.06

10.2
10.7

»9
12.6

12.7
12.0

6.0
5.5

5.4

4.6

100
103

116
115
118
114

1200 1600

2100 2100 1900 1900

Cannot be put in bed because spiders are not possible

The confession of "Wmeeer beeeicnnet die 3cheeIe-Breohte" per * door the pads in hot we, eeer tone overruok.

CO CO - <3 CO OO

cn

The threads of the comparison search 1 and 2 had not an annular cross-section »but an oral one or cocoon-like shape and were further made up of a twofold structure consisting of skin parts and Core parts consisted of · On the other hand, the threads had according to the ■ Examples 1 to 4 have an annular cross-section and, as can be seen from Table I, a large critical draw ratio in addition to its excellent Toughness and resistance to hot water. «

Example 5

3.4 g (2% by weight, based on PVA) boric acid were jbu 830 ecm of water are added and the pH value of the solution is increased 4 adjusted by adding a small amount of sulfuric acid. An aqueous solution of PVA with 17 Gew.-jf was produced by 170 g of FVA with a degree of polymerization of 1700 and a degree of saponification of 99 »5 mol-? 6« u diecer aqueous solution were added,

This aqueous PVA solution was extruded in one length of 96.5 6 per minute from a spinneret with 300 annular openings, each 0.11 mm in diameter spun in an aqueous coagulating bath, which contains 76 g of sodium hydroxide per liter and 122 g of liatric sulfate per liter and was adjusted to pH T4 *. The peacefully spun threads turned from the bath into one Speed of 10 m / min decreased, 100 ^ stretched, with an aqueous neutralizing bath containing 60 g of sulfuric acid and contained 300 g sodium sulphate per liter, neutralized, then a hate-warmth trek of 100 ^ with an-, Sclilie sowing laundry with water and sending it to the chiles. Subjected to dry heat stretching of $ 300, so that thread

8AÖ ORIGINAL

009809/1646

■ It tinea total stretching ratio τοη 1500 i »were obtained ·

The thread obtained in this way had an annular cross-section, exactly corresponding to the shape of the spinning opening, and its structure was homogeneous. The toughness was 15.2 g per denier, the elongation 5 _t 5 ^ and the resistance to hot barrels was 119 ⁰ C *

Compare search 4

The aqueous IVA solution used in Example 1 was placed under the same conditions as there in an aqueous coagulating bath which contained 2 g of hydroxide per liter and 250 g of sodium sulfate per liter and had a pH value

relax
12.7 had The friechgeeponneneii? Were with

Rollers 10O ^ stretched, neutralized, then a ITaQ-tfärme8trecken of 100ίέ, then a ¥ S "che with" aaaer and then a dry-heat a trek of 2Tx) ^ subject, wherein yarns were obtained with a Geaantstreckverhältnie of 1IuO ^ ·

The threads obtained in this way had an oval cross-section and their tenacity was 8.6 g per denier and their resistance to hot water 102 ^c ?:, Both values being considerably worse than those of the threads according to Example 5.

Example 6

To 1000 g of an aqueous P7A solution with 20 Gev. ~ £, dl · 200 g PVA a with a degree of polymerization of 1700 and a "degree of freezing of 99" contained 5 Kol-jt β g (4 eew · - ^, absorbed on PTA) boric acid ugeeetst, whereupon

0 0980971646

the pH of the aqueous solution was divided to 3.1 by adding 1 g of sulfuric acid. This aqueous coating was spun from a spinneret, as in Example 5, into an aqueous coagulating bath which contained 23 g of nitrate hydroxide per liter and 145 g of sodium sulfate per liter and was adjusted to a pH of 13. The free-spun threads were stretched with rollers 100jfc, neutralized, then subjected to a Feublf-tarraeetreokung ron 1009έ, a wash bit water and then a dry-warm stretching τοη 2QQ & , so that threads with a QesanitetreckTerhaltnlB τοη · 1100 *; * were obtained.

The surface of the fibers thus obtained was ring-shaped and they had a honeycomb structure. The tenacity was 12.3 g per denier, the resistance against hot water t13 * r and the critical stretch radius

EichiTersuoh 5

Aeiepiel 6 was repeated, but used as an aqueous Koaguller bath of an old one with a content of 300 g sodium sulfate per liter and 40 g ammonia per liter with a pH value of 11.8. The threads obtained had a flat cross-section and their tenacity was 9.3 g per denier and their resistance to hot water was only 102 ^a> .

Bel «üiel 7

For 1000 g of an aqueous PVA solution with 16% by weight, which contains 160 g of PVA. Pol / merisetionstjrad τοη 2350 and a · "v" lfungsgra4 τοη 99.8 hol-ji contained, were 3 _t 6 g (2.25 wt, -, i, based on PVA) Nutriueborat "uge-

9/16

setst, followed by the addition of a small amount of hydrochloric acid mur setting ^(mgdeV;. pH of the aqueous solution to 4 was These aqueous · FVA solution was co »a spinneret of the same used in Example 5. ax into an aqueous coagulating bath spun welchee 50 g Sodium hydroxide contained 155 g sodium sulphate per liter and had a pH value of 14. The fragrant threads were removed from the bath at a speed of 10%, then stretched with rials 100% and neutral! Then the threads were subjected to NaQ heat stretching of 200%, washing with aaser and subsequent dry heat stretching of 23%, so that α aß lad * η were obtained with an environmental recovery ratio of 1900 ^, the extent of which was ring-shaped whose toughness was 14.5 g # ilenier and their durability

against heißeia Vasser ^r 122 ^c ^ was.

Comparative experiment 6

The experiment was carried out in the same way as in Example 7, except that all aqueous coagulating baths had a: content of 5; 5 ^ ^? g '"Has used # iuniBulfat. per liter and 250 g of ammonia per liter * aAUÄ-e'iue; pi 'pli-a-e'rt of 13.5.

The wuereclinitt uer erli & l'teneh thread was oval and their toughness was 9.5% per lienier, their resistance to hot water as se r 104 ^ and their criticality Stretch ratio

Example £ - - · - '.

To 1000 g of an aqueous iYA solution of 14% by weight, which is 140 g of IVA with a polymer!

. .- ■ i'ii '■■' - ■

0 0 98 υ 9/1 6 U 6

and a degree of saponification of 9918 MoI-Jt 3t5 g (2.5 wt .- #, weighed on PVA) boric acid added, whereupon a small amount of nitric acid to divide the dee pH of the aqueous solution to 3 was added. These Aqueous solution was spun from a spinneret of the type used in Example 5 into an aqueous coagulating bath, which 35 g sodium hydroxide per liter and 143 g sodium sulfate per liter contained j and a pH value of 13.8 would have. The freshly spun threads were orphaned with 100 ^ stretched and then the alkali adhering to the threads in a neutralizing bath, which contains 60 g of sulfuric acid each Liter and containing 300 g of sodium sulfate per liter, washed off. The threads were then subjected to wet-heat stretching from $ 100, then a wash with water and then Subjected to a dry-warm stretch of $ 200

The threads obtained thereby had an annular cross-section exactly corresponding to the shape of the spinning opening and the tenacity of the threads was 11.8 g per denier and the resistance to hot water was 119 ¹ C.

Comparison tests 7 to 10

These tests were carried out in the same manner as in Example 5, but those listed in Table II Conditions applied.

009809/164

Table II

Test amount pH value aqueous coagulating bath 2fr boric acid, the composition (g / l)

aqueous sodium sodium

beasogen

on PVA (Qew - ^)

called lohydroxyd aung

Lum sulfate

PH

whizzed * Streokver " ratio of threads

Cf. 7 * Q «9 ¹¹ 10

0.5 2.0 2 * 5

3.5

4 6

4.2 5.7

50

50

110

50

150
ITO
145

80

14 14 14 14

1100 10Q0 1050

The following results were obtained *

In Vergleichaverauch 7 was due to the slow Koaguliergeechwindigkait an unacceptable adhesion between the threads · The toughness of the resulting filaments was 10> 4 g 3 © denier * their resistance to hot water was 102 ⁰ C, and the critical draw ratio was 135o #.

In Vergleichsvereuch 8 inageearat a spider was possible jedooh found a common thread break instead · The toughness of the resulting filaments was 8.6 grams per denier, resistance to hot water was 102 ⁰ C, and the critical draw ratio was TQ50 #.

In Comparative Experiment 9, it was difficult to apply tension during the spinning of the filaments due to the rapid coagulating speed, and the filaments were frequently broken. The filaments obtained had tenacity of 10.6 g per denier, resistance to hot water of 105 ⁶ Cr and a critical draw ratio of

0 0 9 8 0 a / / j: β 4 6:

Bel comparison test 10 wax due to the spinnability bad for the fact that the rate of hydration was too slow at the time of spinning. Although it was possible to make threads by delaying the spinning speed to train to the utmost extent, the threads obtained had no properties, which would have been necessary to measure · The critical stretch ratio was $ 1200.

Claims (1)

Claims 17 A process for the production of polyvinyl alcohol with a ring-shaped outer cut and extended extensibility, characterized in that ale spinning solution is an aqueous polyvinyl alcohol solution with a concentration of 10 to 30 wt .-; Fe mwUmit. a content of 1 to 5% by weight, based on polyvinyl alcohol, a water-soluble boric acid compound, the pH of the solution being adjusted to 3 to 5, and this aqueous polyvinyl alcohol solution from ring-shaped spinning orifices into an aqueous one coagulating bath containing 20 bie 100 g alkali hydroxide per liter and 100 bia 180 g sodium sulfate ie liters, Wubei the iet adjusted to 13.5 to 14 pH-Aert dee.Badee, is spun. 2. The method according to claim 1, characterized in that that boric acid is used as the water-soluble boron compound. 3. The method according to claim 1, characterized in that daü as a water-soluble boric acid compound acid salt is used. 4. The method according to claim 3 »characterized» that nitrium borate is used as boric acid sala. 5. The method according to claim 1 "to 4, characterized in that sodium hydroxide is used as the alkali hydroxide will. 6. The method according to claim 1 to 4 $ characterized in that al8 alkali metal used potassium hydroxide will. 7 · Process for the production of polyvinyl alcohol threads with circular cross-section and excellent Extensibility, in particular according to claim. 1, thereby 0 ΰ 9 8 C 9/16 4 6 gf know rejects; that as a dope "in · w Brige Poly" ▼ inylalkonollösung with a Konsentration 14-20 QEV »- £ uM with" inen Cthait death Z to 3 percent · - ^ besogen to £ ₉ tolyrioylalkohol a ·? wasetrlöilielmii boron » where the pSMfcrt £ ·? L ^ cimc on 3 bie f is _e TOrweadet viri uad dies «v & firigc PoIy at a f * tipm * BS tos 20 to 40% from afifigförttii | 5 «E SpionOffimsgea in ei» wllSsrigee bad, w # loek * 40 to 80 «AlkaliiqrdToiTA per xiter and 120 up to 150 β iratrium sulfate j # Mter «athS, where the pH * The value of the bath is set to 13 «S to 14, the spinning is β 009809/1646