WO2003044251A1

WO2003044251A1 - Production of nylon-6 filament yarn

Info

Publication number: WO2003044251A1
Application number: PCT/IN2001/000207
Authority: WO
Inventors: Radheyshyam Mantri; Avinash Dubey
Original assignee: Radheyshyam Mantri; Avinash Dubey
Priority date: 2001-11-21
Filing date: 2001-11-21
Publication date: 2003-05-30
Also published as: AU2002222499A1

Abstract

Production of Nylon-6 Filament yarn and subsequent drawn crimped/flat yarn with enhanced productivity gain to a level of 10-22 % at melt spinning step by incorporating 0.5 to 2.2 % by weight of specific polymer having a recurring unit structure represented by formula (1) based on the Nylon-6 main fibre polymer predominantly in the form of inclusions and a spinning take-up speed of 5000 mtr./min.and above. In formula (1), R1 represents an alkyl group having up to 5 carbon atoms, R2 represents a carboxylic acid ester in which alkyl group having 1 to 5 carbon atoms and n is a positive integer such that the average molecular weight of specific polymer (1) ranges from 10000 and above.

Description

PRODUCTION OF NYLON-6 FILAMENT YARN

DESCRIPTION

1) Brief description of the invention :-

The present invention discloses a novel manufacturing route to Nylon-6 partially oriented yarn and subsequent drawn yarn with enhanced productivity by incorporating a specific polymer to nylon-6 main fibre polymer at melt spinning step.

2) Background of invention:-

Narious methods are known for manufacturing polyester filament yarn in which productivity could be enhanced either by incorporating chain branching agent, such as pentaerythritol etc. during polymerization stage (Japanese patent Application laid-open specification no. 292/78) or by mixing specific polymer such as imidated polyalkyl acrylates (US patent 5,565,522) during melt spinning of polyester filament yarn. Another known method utilizes a heated chimney at spinning stage. In all these methods the productivity depends upon increasing output of a melt extruded from a spinnerette in melt-spinning and taking up speed of polyester yarn. In normal process the molecular orientation of spun yarn is generally enhanced with the increase in taking-up speed resulting in decrease in residual elongation of POY and subsequently draw ratio is to be decreased during drawing and hence the productivity effect is less even if the amount of extruded melt is increased. The subject methods are used to control the enhancing molecular orientation resulting in a high residual elongation of undrawn polyester yarn in which drawing at a high draw ratio is possible and thus productivity gets increased.

Literature survey reveal that little work is so far done to enhance productivity of nylon-6 filament yarn at melt spinning stage through additives, the references available pertain to only polyesters of different types. In case of nylon-6 the known processes involve manufacturing of nylon-6 polymer suitable for high speed spinning only by incorporating chemicals such as dicarboxylic acid and diamines during polymerisation of caprolactam and not at the spinning stage (German offen DE 19,854,421 & JPN 2001 3,227). Hence the inventors took the opportunity and have c arefully done research in case of nylon-6 partially oriented yarn (POY) by adding specific polymer (1) in the melt of Nylon-6 and obtained POY having high residual elongation. This increase in residual elongation during POY spinning could be due to retardation of molecular orientation which enables higher draw ratio and thus the increased productivity of POY through higher spinning speed.

3. Summary of the invention :-

The object of the present invention is to provide a novel manufacturing process for the production of Nylon-6 partially oriented yarn and subsequent drawn yarn with vastly improved productivity by incorporating specific additive component at the melt spinning step and hence is of very great industrial significance.

a) Dried Nylon-6 polymer in the form of chips is fed continuously into the extruder.

b) Specific additive (1), in this case a polymer, is also fed into extruder as separate stream using mass dozing machine.

c) The homogenous melt passes through spinnerettes.After spinnerettes cooling of yarn takes place and subsequently spin finish oil is applied. Partially oriented yarn (POY) is then wound up over paper tubes.

d) The POY is subsequently further drawn using draw texturising or draw twisting machines.

e) The additive polymer (1) added to Nylon-6 was varied between 0.5 to 2.2% by weight. f) Polymer could be spun at different speeds depending on quantity of additive added at take-up speed of 5000 mtr/min and above, against conventional speed of 4100 mtr/min.

During the process high residual elongation was obtained and a productivity gain of 22% was achieved by incorporating specific polymer(l) and using higher take- up speeds without materially affecting properties of POY or performance in after treatment. Hence the industrial significance of the process is very great with a potential to go for further increase in productivity by optimising addition of specific polymer(l) and spinning take up speeds.

g) The process trials were conducted in all types of nylon-6 filament yarns in different deniers/filaments with circular & all other types of cross sections. Other value added yarns were also produced by using additive (1) admixed with coloured master batches.

4) Detailed description of the process

a) The Nylon that is used in the present invention is a Nylon-6 having fibre forming properties. It may comprise additive such as delustering agent, a terminating agent and any other additive as necessary. Nylon-6 polymer used was suitable for textile grade yarn processing.

b) The specific polymer(l) which can be added to Nylon-6 may be polyacrylates and derivatives thereof, polymethylacrylates and derivatives thereof. The polymethyl methacrylate (PMMA) is specially preferred having average molecular weight ranging from 95000-105000 which has good availability and reasonable price comparable to nylon polymer.

The exact mechanism of PMMA in enhancing residual elongation is still not investigated. However, it is known ( text book of polymer science by Fred W. Billmeyer, page 266-67 ) that the effect of the side groups in some atactic polymer such as PMMA combined with strong interchain forces the polymer may have a structure that is intermediate in kind between crystalline and amorphous. As in case of polyacrylonitrile, steric and intramolecular dipole repulsions input lead to a stiff, irregularly twisted, backbone chain conformation. The stiff molecular chain pack like rigid rods in lattice array; lateral order between chain is present but longitudinal order along chain is absent. Similarly in case of additive polymer (1) the effect is due to conformations of additive (1) molecules having bulky side chains distributed randomly thus creating low mobility of molecules and thus the orientation of nylon-6 molecules get retarded and therefore resulting in higher residual elongation during spinning.

c) The incorporation of the additive (PMMA) 0.5 to 2.2% by weight of Nylon-6 is expediently carried out prior to extruder using mass dozing machine in the form of granules as well as in master batch form (masterbatch made from Nylon-6 polymer of textile/technical grade and PMMA. PMMA content in masterbatch can be from 20-40%).

d) Virtually all types of known spinning process are suitable for producing POY. In the present invention the POY machine used was of Barmag 9E4, 64 end godetless spinning extruder. The production of POY is possible virtually at all technically possible take-up speeds. Trials have been taken in particular with take- up speeds ranging between 4100- 5000 mtrs./min. The properties of POY produced in the invention were comparable with that of POY produced substantially free from PMMA. The achieved productivity gain of a level of 22% is therefore a merit of present invention in which POY could be produced at take- up speed of 5000 mtrs./min having high residual elongation and which has not yet been drawn to the breaking extension required for the particular application. The comparable POY properties and spinning process parameters are listed in Table - 3. e) The POY was then further drawn and crimped/textured/air textured on draw- texturising machine (Barmag FK6-900) operated on 500 mtrs/min speed. All types of known draw-texturising machines are suitable for producing drawn crimp yarn. The properties of drawn crimped yarn and draw texturismg process parameters are listed in Table - 3. The properties of drawn crimped yarn were found comparable with normal yarn in which no PMMA was added.

f) The POY was also drawn on draw twisting machine ( Ishikawa ST 120, 2E, 16S ) operated on 925 mtr/min. The properties of resultant flat yarn were found comparable with normal flat yarn in which no PMMA was added. Machine parameters and properties of resultant yam are listed in Table-3.

g) In melt spinning process all the parameters were kept constant for both POY i.e. POY with PMMA and POY without PMMA, % additive polymer and take-up speeds were the only variables. Similarly the draw-texturising or draw twisting parameters were kept same.

h) Table- 1 represents the results of 1% PMMA addition at different T/up speeds. It is apparent from the table that the residual elongation and elongation increase ratio increases with increasing take-up speeds when compared with POY without PMMA at the speed of 4100 mtr/min i.e. 76.6 to 94.4 and Oto 23.2. It is also clear from the data that if the speed is increased from 4100 mtr/min. to 5000 mtr/min. and addition of additive (1) is kept constant i.e. 1%, the residual elongation and elongation increase ratio % gets decreased i.e. from 94.4 to 77.9 and 23.2 to 1.7. If the take-up speed is further increased beyond 5000 mtrs./min. frequent filament breakages occurred and spinnability deteriorated, may be due to limitations of spinning machine and take-up equipment. It is established from the data that by incorporating 1% PMMA, spinning process could be run without problem at 5000 mtr/min. as compared to 4100 mtr/min. with comparable yarn properties and thus a gain to a level of 22% in productivity at spinning stage is achieved. The data were generated on Nylon 55/10 (Den/Filament) semi-dull partially oriented yarn.

TABLE -1

EFFECT OF ADDITION OF 1% PMMA ON INCREASING TAKEUP SPEEDS

Run Take- up Ability to Tenacity Residual Elongation Remarks

No. speed be spun (g/de) Elongation increase

M/mϊn % Ratio(%)

1. 4100 good 3.90 76.6 0 Comparison(Normal without PMMA)

2. 4100 good 3.94 94.4 23.2 Comparison

3. 4300 good 3.64 90.4 18.0 Embodiment of present invention

4. 4500 good 3.70 85.0 11.0 -do-

5. 4700 good 3.75 83.2 8.6 -do-

6. 4800 good 3.82 81.1 5.9 -do-

7. 5000 good 3.90 77.9 1.7 -do-

8. 5300 Could not be Comparison operated due to heavy wraps ; at

Take-up machines.

i) Table - 2 shows the results of increasing percentage of PMMA at Take-up speed of 5000 mtrs/min. It is clear from the table that at constant speed the residual elongation increases with increasing amount of PMMA. Trials were taken up-to 2.3% dosing of PMMA. While it was possible to spin the yarn at such high dosing ratio due to very high elongation at above dosing, performance could not be established. Higher speeds trials were difficult due to limitations of take-up equipment. However, inventors are of the view that given the availability of high speed equipment operations, higher take-up speeds are also possible for production of yarn with comparable textile properties. Processibility of such yarns at draw texturising or draw twisting will of course have to be established. The data pertains to Nylon 55/10 Semi-dull POY. Since higher elongation data are achievable without seriously affecting tenacity properties, higher operational speeds than 5000 mtr/min are possible at higher dosing ratio by giving availability of suitable equipment.

TABLE - 2

TRIALS WITH INCREASING AMOUNT OF PMMA AT CONSTANT TAKEUP

SPEEDS OF 5000 MTR/MIN.

Run Mixing Ability Tenacity Residual Elongation Remarks No. ratio to be (g/de) elongation increase

(% PMMA Spun (%) ratio(%>

1. 0.5 good 4.40 65.3 - Comparison

2. 0.6 good 4.20 66.0 1.1 Embodiment of the present invention.

3. 0.7 good 4.11 69.7 6.7 -do-

4. 0.8 good 4.01 72.1 10.4 -do-

5 0.9 good 3.95 74.8 14.5 -do-

6. 1.0 good 3.90 77.9 19.3 -do-

7 1.2 good 3.80 80.3 22.9 -do-

8 1.5 good 3.72 86.0 31.6 -do-

9. 2.0 good 3.60 93.3 42.9 -do- bet be ope- .... Comparison rated due to heavy wraps at Take-up machines. j) Table-3 pertains to spinning conditions and properties of semi-dull POY with 1% PMMA at the take-up speed of 5000 mtrs/min. The draw texturising/draw twisting parameters and drawn crimped/flat yarn properties are also shown in the Table-3

TABLE- 3

Normal Bulk Prodn.

(without PMMAΪ fwith 1%PMMA

A. Spinning parameters

0) Parameters of operations

Raw Denier 54.0 54.0

No. of holes in spinnerette 10 10

Extruder final zone temp. deg.C 262 262

Take-up speed Mtr/min. 4100 5000

% PMMA 0.0 1.0

(ϋ) POY properties

Denier 52.0 52.0

Tenacity (g/de) 3.90 3.90

% elongation 76.6 77.9

B. Draw-texturising machine parameters

0) Parameters of operations

Stretch ratio 1.237 1.237

D/Y 2.29 2.29

Ceramic disc combination 0+7+0 0+7+0

Temp, of heater deg. C 175 175

Yarn speed mtr./min 500 500 TABLE - fcontd..

Normal Bulk Prodn.

(without PMMA) (with 1%PMMA

(ii) Crimped yarn properties

Denier 46.0 46.1

Tenacity (g de) 3.9 3.9

% elongation 34.7 34.5

% shrinkage on hot water boiling 5.4 5.2

% crimp 44.2 45.0

C, Draw twisting parameters

⁽0 Parameters of operations

Stretch ratio 1.25 1.25

Yarn speed mtrs/min. 925 925

Air pressure kg. 2.5 2.5

(ϋ) Flat yarn properties

Denier 47.7 47.3

Tenacity (g/d) 3.8 3.9

% elongation 43.2 42.8

% shrinkage on hot water boiling 12.1 12.4

k) It is apparent from the foregoing description that according to present invention, the productivity of Nylon POY at spinning step could be enhanced substantially by incorporating PMMA during the production of POY with the retention of all required quality norms as that of corresponding Nylon POY without PMMA. The process is very simple and with slight effort the take up speeds can be increased to 5000 mtr/min. against normal speed of 4100mtr/min. to get the enhanced productivity, therefore the industrial significance of this invention is very high. 1) Similar improvements have also been observed in case of yarns with different lustre and profiles. For example in bright trilobal yams there was no adverse effect in brightness and shine even by using additive (1). Using additive (1) admixed with coloured master batches, dope dyed yams can also be produced without any adverse effect.

This indicates that present invention embodies in itself wider ramification for productivity improvement of different types of nylon-6 filament yarns with different lustures, profiles & denier range.

m) The present invention has much wider ramifications, since this covers not only the crimped/textured/air textured yams but also the filament yams produced from draw twisting machines.

n) Comparative dyeing of all the resultant yarns of PMMA trials were done. No significant change was observed in dyeing behaviour of resultant yarn so produced by addition of PMMA and that without PMMA.

Claims

1. A Nylon filament yarn comprising of Nylon-6 as main polymer component and 0.5 to 2.2% by weight, based on the main component, of polymethyl methacrylate in granule as well as in the form of masterbatch granules made from Nylon-6 polymer.

2. A Nylon partially oriented yam where higher elongation increase ratio is obtained by incorporating specific additive polymer represented by formula (1)

3. A process according to claim 1 wherein partially oriented yarns are produced at filament Take-up speeds of up to 5000 mtr/min and higher.

4. A process according to claim 1, 2 & 3 describing productivity enhancement to a level of 22% and higher in Nylon partially oriented yarn.

5. According to claim 1, 2, 3 and 4, a drawn flat, crimped, textured, air textured, conventionally dyed and dope dyed yams in all profiles, lustres and shades produced with comparable qualities vis-a-vis conventional yarns.

6. A process for the production of crimped, textured, air textured, flat filament yarns and yarns with other embodiments, according to 5.

7. Process applicable to complete range of textile/technical grade nylon-6 yarns in different deniers covering various lustres, profiles, shades and other embodiments.

8. Comparable dyeing behaviour vis-a-vis conventional yarn.