DE1785222A1 - Melt spinning process and device for its implementation - Google Patents

Description

execution

The invention relates to the melt spinning of man-made polymers j in particular a process for spinning polymers of higher melt viscosity without degradation of the polymer and under reduced orientation of the polymer in the spun thread fabric, and is particularly suitable for forming threads with a Endiitei * in the stretched state of less than 50 den.

When filaments are melt-spun, they become artificial idnear polymers to form the threads that are gathered into a bundle, , melted, through the filter of a spinning construction, and then through Spinning capillaries driven and quenched. Daa bundle of thread becomes further treatments to develop the desired physiochon Subject to Eigenochafton, and the thread or yarn product is finally packed for dispatch. Most of the melting

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109882/1499

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Spinnable polymers are thermosensitive and are subject to ^ increased t temperatures rapidly lead to degradation. The one to drift through the molten polymer required pressure through the spinneret is-the higher, the lower the spinning temperature is · At to If the spinning temperature is low, an uneven flow occurs and a melt fracture. Accordingly, a compromise is always made between siner in the interest of good spinning high spinach temperature and low spinach temperature in the interests of minimal polymer degradation.

Another approach to the problem of reducing the spinning pressures is to enlarge the capillary. If the same thread size (denier) is desired, this method requires a more precise refinement, ideally before solidification, of the molten material leaving the spinneret. This © but stretching can regrettably rare-at errlen me the ideal conditions sufficiently approximated durchgeftOart \ ^ vm which to avoid the Faaengut-Endeigens-chaftan-adversely affects one spin orientation, ^also! oeiia spinning a coarse thread of the inner part is not properly quenched due to the insulating properties of the outer part. This results in uniformities across as well as along the fiber. Often, hot gas tempering must be applied directly below the spinneret in order to counteract these disadvantageous effects and obtain a more uniform product, but this is in terms of investment as well

109 83 WA Λ 9 9 bad origsnau

DP-675 is also costly in terms of labor.

Yet another attempted approach to the present Problem -. The melted polymer becomes on a relatively kept low temperature until it is passed through a behsiz'ce spinneret which is on a far over that of the melt, is kept at a temperature < Heating takes place. However, this way of working has proven to be not Proven to be practicable because the polymer is in contact with the head surface the spinneret stagnates, becomes too hot and breaks down subject.

Bie efforts still better Padenmaterialien set "continuously sen continuing * We know now that improved physical properties' s. As a higher tensile strength _f higher by ■ Polymers ■ Sehmelsviacosität either hochmoj.8kulsrer using PÖIymereroder polymers with stiff it. However, chain structure available- SINCL Bies leads GiBiBSes swischen high spinning temperatures and high Spir.näxticlcGix beef dear iCspillargrösse to further complication of KömpI ^first in several cases has 8ic & ily Herstellixng ^ ron Fadeniaaterialien commercial grade from liochvlscosen. proven Polymeren.-impossible. The process according to the "invention" now enables the spinning of such polymers, "Beruidereii" polymers, it results in a reduction in the spinning material and allows the formation of better big , stretched, thread products ·

109882 / U99,

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DP-675

The present invention provides an improvement in relation to the aforesaid methods and spinning assemblies of the type in which molten artificial linear polymer is placed in a filter holder with one thread sufficient for the subsequent ejection Pressure is supplied through the filter media in the filter happens and ejected through spinning capillaries in a spinning plate will. According to the invention, the spinning plate of the Filter holder separated by an insulating medium and are the Spinning capillaries formed by hollow inserts in the spinning plate, the passages through the insulating medium from the filter holder form. The spinning process is

a) the molten polymer through the filter holder at initial temperatures (block temperatures) in a temperature range passed below a value at which a substantial Degradation of the polymer occurs,

b) the polymer passed into a number of passages, their each leads to a different spinning capillary in the spinning plate and an input stone device in this initial temperature range Has, , ,

c) the spinning plate to increase the temperature along the passages from the temperature value at the entrance to at least one 60 ° C higher temperature at the spinning capillary and heated

d) the polymer from the spinning capillary through after a running time ejected the heated passage for a maximum of 4 seconds.

The invention is described in more detail below with reference to the drawings

T09882 / U99

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DP-S75

very love, in which shows j * -

Pi |. 1 shows a preferred spinning structure in section in a through the middle axis of the plane laid down, <

figi-2 Large view of a Seila by Pig »1, Hg * 3 in s'cheiiatischer representation Profiles of the temperature in the polymer ^^ i ^ i different places in the tubular passage of my hollow insert, .-"..;"'Pigif ⁴ ^ a schematically shows the bulge and temperature profile at

nntien spinning and

^J öblieiiiatisöli the bulge ~ and temperature profile in the "improved spinning process according to the invention.

¥ i | rfeiiig. 1, form the cover plate 10, the filter ear 12 and ^ the, Spinnauf construction 14 the main elements of the spinning arrangement. Me plate 10 is by means of screws 16 and the spinning Ä 14 'in the same way with screws 18 to the pilter holder

_t 12 anösetzb. The entire arrangement is fastened in the spinning machine mlttsls Sclirauben 20. From the inlet opening 22 on the top surface of a cover plate 10, a number of

24 to the lower surface of the plate, and from the 26 in the J ¹ IIterfaalfcer 12, the sand and bav /. or sieves

The sealing ring 30 attached to the filter holder 12 and the spinning assembly 14 is of sufficient thickness to form a distribution space 32.

3P-6T5

As shown in nMier in]? Ig, 2, the clay has SchrauT) p% .44.

held spin structure. H an upper plate 34, 36 and a lower plate (Spinnpla-fcte) 38, called a spirally wound, electrical lieizelemoTii; 40 is embedded. Ber Al) stands] iai a Luftreiim sv / iscnen Oer upper plate 34 '"ü» ä ä 36s as the .Wärmesperre · between these two plates pi

In the top plate 34, for each thread to be spun, there is a bottom surface or lower plate 38 of a leading hollow insert 46

set ₃ whose yerMltnisiaass long / circular © i? 48 the head surface of the plate 34 with the end capillary © * §0 det. · .. ■ ^ ■ - · ■■ -: ■: ■: '■ ■ ·. ■ _·: v _t .. ■ ;, .- -

lsi operation will; Gesdnablsenes Poljrmeres from a> (^ iijht e: Uig.ef seiclinetea) Bosiörpmiipe der linlEssöffmmg? 2 (Figv.i;); under _,; Driiök led nn & νοπ deti'-tert splitter channels "24 g of the upper (Deil ^äes". Eolilreuma'26 and after IPr.itexung and äwTOh the passage durcii th sand sieves "ADR τρη the channel at 28 dom 'Tertöilöirauln 32 ^ smgeteiitv TBIA In this case, sololioic temperature control conditions are maintained, ciaas the 33 ^{! r} gssclmiolsetien polymers in the partition space 32

Glsicli the ^ ßiiigen the angular metal iate. Hü r feaperainir will "from ■■■■ gasclimolse.ne Folyßfere then into the

Men öQr missions for the Ufimien aue Uife: ir.LsTeii ^ y pressed-, from äen ^ ii it emerges in the form of threads »Durc ton "" denf öiäktrißchen Heisjeleme "nt 40 supplied

, ■ · '. -at

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the temperature of the lower plate 38, heating plate 36 and lower Part of the "stake to at least 60 ° 0 above that of the listed polymer melt held. Due to the insulating properties of the air space between the plates, only a very small amount of this heat reaches the top plate 34, which is at essentially the same temperature as the molten one Polymers remains. Due to the resulting temperature difference, the poor heat transfer properties of the polymer and the extremely short time (maximum 4 seconds) that the Polymers with "the high temperature parts of the Inserts 46 remains in contact, the polymer receives a steep temperature gradient when flowing through jGdos insert 46 «

3 illustrates temperature profiles of the polymer as it flows through part of an insert 46, an upwardly directed polymer flow being shown so that the temperature chs £ - -in. The figure τοη shows increasing values from bottom to top » Zn beginning is the temperature profile across the polymer in use ε <-S _? as T_ (corresponding to point a in Pig * 2) shows, essentially constant, while curve T ^ shows the onset of a temperature gradient at point b. Immediately before the polymer enters the capillary 50, d, aa point c, there is, as the curve T explains, a steep temperature gradient. At a higher temperature of the walls of the inlet hole, the outer layer of the polymer has a lower apparent viscosity. Dexsum "- forcing the polymer in from the inlet hole 48

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pressure required into capillary 50 and propelling therethrough is accordingly substantially reduced, although the temperature of the main mass of the capillary 50 flowing through Polymer is not increased enough to have a material effect on the polymer.

Fig. 4a shows the bulge ("carrot") below a Spinning capillary of sufficient size around a highly viscous polymer to spin with a reasonable pressure drop Line 60 shows the temperature profile across the polymer immediately below the capillary, noting that the temperature of the The middle part is slightly above that of the outer part · The line 62 shows the temperature profile at a small distance from the capillary. Because the exterior of the polymer is made by a quenching medium is cooled, the middle part now has a considerable amount higher temperature than the outside. It has shown and is well known that this temperature profile leads to irregularities in a thread.

Fig. 4-b shows a relatively smaller capillary used for spinning of the same polymer can be used if a heated capillary spin assembly according to the invention is used. The figure explains them because of the lower shear and low pressure stimulation for the propulsion of the polymer through the capillary resulting in reduced bulging. Furthermore, in order to achieve the same thread denier in these

'., :: ■. 10M82 / U99 BADORK ₃₁ NAL

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Under these conditions, only a lower spinning stretch is necessary. the Line 64 shows the temperature profile immediately below the Capillary outlet, it should be noted that the outer parts of this thread are hotter than the inner parts. The line 66 illustrates the profile a short distance below, after a certain Cooling has occurred, and this time it can be observed that the temperature gradient across the sram thread is very small. This results in a more consistent product.

The »heated capillary generating the steep temperature gradient sets the shear stress on the capillary wall without excessive, thermal degradation of the polymer, Feraeai can load materials with low birefringence in the case of smaller spinning regions because smaller capillaries can be inserted without an excessive pressure drop.

In other embodiments, each insert can have several long entry holes and capillaries, which is particularly advantageous if the capillaries are arranged in a straight row. It can also be from hats, in the air space between the upper and lower plates, heat shields or barriers

The following examples serve to further explain the gate parts according to the invention, without this being restricted to them. In the first two examples, the spinning of high-

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molecular polymers that cannot be made with conventional spinnerets are spinnable, according to the method according to the invention and in the two following examples, the reduction of the spun thread orientation and improvement of the properties of the stretched load explained, which according to the method according to the invention is obtained »whereby also good spinning without the hassle a hot gas tempering becomes recognizable.

In the following examples, polyester poly (2-methylhexamethylenterephthalamid), the polyamide for explaining chosen, but the invention can advantageously also in other polymers of high melt viscosity to apply, such as high molecular weight poly (hexamethylene adipamide) _t poly (hexamethylene isophthalamide), from p-Xylylenediamine and azelaic acid and the polyamide from bis (4-aminocyclohexyl) methane and azelein, sebaein, dodecanäi- cross hexadecanedioic acid, polyethylene, polypropylene, polyvinylidene chloride and polyvinyl chloride.

Example!

Polyethylene-2,5-naphthtialinaicarhoxylate was prepared according to US Pat. No. 3,123,587 with the aim of achieving this superior tensile strength properties load with one (in uverallung mil; good behavior during processing) to achieve the highest possible molecular weight, became a number smaller Approaches polycondensed to a high molecular weight. the

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Table I gives the inherent viscosity of the various poly ineransatz © for the Schraelz spinning test; the inherent ¥ isco3ity ( % ^ Λ is as

defines where C is the concentration of the polymer in the solvent, trifluoroacetic acid / methylene chloride (volume ratio 25: 75), in g / 100 ml (nominally 0.32 g / 100 ml), θ.the dripping time of the polymer solution through the BÄfillarviscoaimeter in sec. "at 25 ° G and θ the time the solvent drips through the capillary viacosimeter in seconds" means "at 25 ° C".

For the polymer viscosity, which allows melt processing according to conventional Sehmelzspinnteehniken, "Isisher has an upper limit of the molecular weight of about % ^^ _L £ 0.85. At higher molecular weights a melt fracture results which prevents continuous spinning. In the examples of Table I, which are carried out with conventional spinnerets, a high spin block temperature of 320 to 325 ° C has been used, which remedied the melt breakage to a certain degree, but was not sufficient to eliminate the problem. "Temperatures led to the breakdown of the polymer melt. When using the heated B ^ apill ^ rspiana construction according to the invention, even with a significantly higher molecular weight, there are no melt breaks

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Problems arise. You expandability of the spun! at high molecular weight and the resulting physical properties were in the heated capillary spin assembly Well. A direct comparison with conventional thread material is not possible because the melt fracture caused processing of the thread material made impossible at these higher molecular weight values. At the lower molecular weight values of the conventional Samples of Table I, the extensibility was quite low and the physical properties were inferior.

109882/149 9

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at
game Spinnätiaen-
auffcau Deterrent
solar
Tempering
contraption block
tempe
rature,
o ₀ Kapil
lar-
tempe
rature,
93 Inherent
flake Viscoeity
3? Adengut Boppel
"refraction ^ Streckver
ratio ö
"X"
as
vn hot wall
{390 G) 325 325
(approx 0.84 0.76 0.0045 4t7 1-S conventional no 320 320
(• approx 0.78
•) 0.72 0.0176 4.8 1-0 capillary no 312 394 1.26 0.90 0.0135 4.8 Ί-D Ibeisste
capillary 15.2-.CiQ-
Third move-
•! »Eitorgan 315 392 1.26 0.87 0.0057 5.7 1-E heated
capillary Verpög »-
Governing body 310 393 0.93 0.87 0.0008 6.1

DP-675

Strength, addition, modulus, g / den $ g / den

4.9 11 188 6.0 8th 173 7.3 12th 218 7.0 6.4 151 6.1 9 »?

109882/1499

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With e τ> 1 el 2

Poly ('bicycloliexyl-4,4 ^l -ctimethyle] i-4f4'-MbCnBOEt), obtained according to British patent specification 979 401 and subjected to an increase in molecular weight by polymerization in the solid phase, was heated and through a conventional spinneret and a heated capillary pin structure according to spun the invention. Table II lists the important parameters. Small, heated capillaries (experiment 2b) gave a stretchable, smooth pad material, while when using conventional capillaries of sufficient size to avoid melt breakage (experiment 2a), the pad material in the essentially non-stretchable and no pad material was obtainable from fine-denier yarns with good tensile strength properties _e

When repeating the experiment with the heated capillary « Spin construction according to the invention with reducing the capillary temperature to the range from 360 to 375 ° C was easy Observe melt fracture.

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attempt

Spin construction
Kapillarabmessuiigen diameter, ium.

Lye, sm

Bloect temperature, ⁰ C capillary temperature, ° G inherent viscosity

flake
Thread material

Properties of the spun thread material

3? a b el 1 e II

2-4

Stretch ratio strength, g / den elongation, $. Modulus, g / den bending fatigue strength

2 B

herköismiicli heated capillary 0.43 0.23 1.07 0.30 295 295 approx. 295 390 Ö, 95 ^X) 1.00 0.80 0.79

rough surface, even titer

with light with light upper

Melt fracture, surface roughness,

102 den, 32 WMm 118 den, 30 mden

1.15 2.30

1.8 3-6

11.1 13.2

4-1 49

224 815

x) with 5 i
xx) maximum achievable stretching ratio using

a hot shoe at 175 ° C and stretching at 175 ° C

The fatigue bending condition is defined as the range of bending cycles up to the failure of the median of individual wheel samples when tested on a device of the type "Masland Flex ίseter" at 21 ° G and 62 1/2 # relative humidity, with the thread at a load of about 0.35 g / denier is bent over a thread of t, 05 mn , which is carried out with 150 Ms 1? 4 cycles / ΆΙη. an arc of *

180 through chwixigt.

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BATH ORIGINAL

if *

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B e is η j e 1 3

In order to finally form a stacked product, anomalous polyethylene terephthalate melt was spun through a conventional spinneret and a heated spinneret assembly according to the invention. In the case of the conventional spinneret (Experiment 3 ~ A), the threads were spun in an inert gas at 360 ° C in a tempering zone of 15 cm in length, to which a delay guide of 41 approx ca and then a radial quenching unit connected. The spun yarn was washed at a throughput of 17 kg / oe. at 940 m / min, wound up "The stretched pad material from several bobbins was then combined and stretched to a stretching ratio of 4.0 on a stack stretching device, with the properties according to lamelle III",

In the Palis dea -heated eapillary spinning structure (experiments 3-B and 3-0) a small volume of inert gas (26 to 57 l / dew) was used to coat the spinning plate, but no heat was added to the gas flow. The thread material was spun through a delay length of 4 cm length and an open tree 15 cm to the hadial watch unit and wound up at 940 m / min at a burch rate of 13 kg / hour. Two experiments, 3 ~ B and 3-6, were carried out with polymers of different molecular weights. The products were stretched vie in Run 3-A. The properties are given in Table III.

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A comparison of the samples shows that the thread material from the heated capillary spinning structure according to the invention is much more uniform in diameter and orientation and can be stretched to a high stretching ratio and superior physical properties without showing any signs of unevenness (e.g., breadths) . This result is obtained with the heated spinneret construction without hot gas tempering.

f a be 1.1 e III

attempt 3-A 3 ~ C 192 »■ <. 6.2 Spinneret assembly " herköm-alioh. heated capillary .Capillary number 250 0.28 4.9 Capillary dimensions 0.48 Diameter 0.30 290 4.3 Length, mm 0.51 420 5 * 3 Block temperature »° 0 290 38.5 55 Capillary temperature ^{, 0 C} about 290 ° 0 Eelative 'viscosity of the 35 33.5. 0.0051 fiber Birefringence of the ge 0.0044 mm spun thread material Coefficient of variation, ^ 13.0 - "■■ ■■ the birefringence Coefficient of variation, i> Θ.3 -. . the diameter Stretch ratio 4.0 4.44 Strength,. g / den 4.7 4.9 Elongation, i> 78 67

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Be is ρ i e 1 4.

Using the same heated capillary pin structure as in Example 3 and with a temper and retractable system of the same type for the control experiment and a small volume of unheated, inert gas when working according to the invention, technical ethylene terephthalate charge was produced.

Three pairs of experiments were carried out, the relative The viscosity of the polymer and the stretching ratio are changed became. The details of spinning and the filament properties n? Table IV, the table values clearly show that with the heated capillary spinning structure, a spun 3-thread product with improved properties without hot gas annealing is obtained and a smaller capillary can be used

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BATH ORIGINAL

Attempt.

4-A

Conventional spinneret design

Number of capillaries Capillary measurements Diameter, mta 0.51, length, mm 0.76

. Block temperature, ο c

Kj normal temperature, approx.

He ί Bsgas-Tempertem-. £ temperature, ⁰ C ι Relative Viscosi-

ft-usgengspoly-

4-B

heated capillary

192

0.28 0.48 295

430

not heated

58

4-0
conventional

4-D

heated capillary

192

0.28 0 »48 285

4-B conventional

0.51 0.76 308

approx * 310 430

not heated

r.) approximate values ■ zx) determination after 24 hours, free Ent-capillary 192

0.28 0.48 295

not received

69

Thread material 51 51 50 51 59 59 Stretch ratio 6.52 6.53 6.30 6.30 6.30 6.30 Strength,
g / a en ³⁵³ / 9.4 9.7 9.05 9.26 9.45 9.54 Elongation, 96 ³ ^ ' 11.6 12.5 13.4 14.5 13.0 12.7 (xevenness,
Swaniungskoef-
efficiency of through-
me ss he s, io 8.7 6.9 8.8 9.0

Claims (2)

1. A method for melt spinning threads with the supply of molten, artificial Mnearpolymerem with a for subsequent discharge sufficient pressure to the filter holder the spinning device, leading through the filter holder and the filter medium located in this and pushing out characterized by spinning capillaries in a spinning plate , that he a) the molten polymer through the filter holder at initial temperatures passes in a temperature range below the value at which substantial degradation occurs of the polymer occurs, b) the polymer in each case leads to a different spinning capillary in the spinning plate leading passages which one Inlet temperature in this initial temperature range to have, c) by heating the spinning plate, the temperature along the passages is increased from the temperature value at the inlet to a temperature at the spinning capillary that is at least 60 ° C. higher, and ^l d) the polymer from the spinning capillary * after a running time through the heated passage for a maximum of 4 seconds. * 20 - 2. Spinning device with a filter holder and a spinneret plate for the melt spinning of artificial linear polymer ^ characterized by an attached to the PiIt he received (12) " upper plate (34) and one arranged parallel to this, forming an insulating space {32) between the two Spinning plate (38), hollow inserts (46) extending through the upper plate and spinning plate, at the end of the spinning plate in each case a capillary (50) is provided for spinning the polymer into threads, as well as by means for Introducing the polymer from the filter holder into the top plate end of each cavity insert (46) and means for heating the Spinning plate (38) with the formation of increasing temperatures along each hollow insert (46) Lee on the side