GB2187481A - Process for shrinking thermically shrinkable fibres - Google Patents

Process for shrinking thermically shrinkable fibres Download PDF

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Publication number
GB2187481A
GB2187481A GB08605724A GB8605724A GB2187481A GB 2187481 A GB2187481 A GB 2187481A GB 08605724 A GB08605724 A GB 08605724A GB 8605724 A GB8605724 A GB 8605724A GB 2187481 A GB2187481 A GB 2187481A
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GB
United Kingdom
Prior art keywords
thermically
fibres
steam
crimping
shrinking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08605724A
Other versions
GB2187481B (en
GB8605724D0 (en
Inventor
Mario Franzoso
Roberto De Lucia
Franco Marton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SIPA ITALIANA PRODOTTI Soc
Original Assignee
SIPA ITALIANA PRODOTTI Soc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SIPA ITALIANA PRODOTTI Soc filed Critical SIPA ITALIANA PRODOTTI Soc
Publication of GB8605724D0 publication Critical patent/GB8605724D0/en
Publication of GB2187481A publication Critical patent/GB2187481A/en
Application granted granted Critical
Publication of GB2187481B publication Critical patent/GB2187481B/en
Expired legal-status Critical Current

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Classifications

    • DTEXTILES; PAPER
    • D02YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02JFINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
    • D02J1/00Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
    • D02J1/22Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
    • DTEXTILES; PAPER
    • D02YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02GCRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G1/00Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
    • D02G1/12Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics using stuffer boxes

Abstract

A process for the continuous shrinking of a top of thermically shrinkable fibres in which thermal (heat) treatment by means of saturated or humid steam is carried out simultaneously with a crimping phase. The process is carried out at the outlet of a stretch-breaking machine.

Description

SPECIFICATION Process for shrinking thermically shrinkable fibres The present invention relates to a process for shrinking thermically shrinkable fibres, and more particularly to a process for the continuous shrinking of a top of thermically shrinkable fibres.
By the term "top", as used in the present specification, there is meant a ribbon without an appreciable twisting, constituted of discntinuous fibres practically parallel and partially overlapping each other.
As is generally known, thermically shrinkable synthetic fibres, such as acrylic polymer fibres, are produced by wet or dry spinning, in the form of a bunch of continuous filaments, generally known as "tow".
These continuous filaments are successively subjected to a stretch-breaking and crimping process in order to obtain discontinuous fibres of variable length, practically parallel and partially overlapping each other, forming the "top".
Usually the "tops" are subjected, under relaxed conditions, to a high-temperature thermal treatment in the presence of humid or saturated steam in order to confer to the discontinuous fibres a greater dimensional stability under heat.
Such thermal treatment is in general carried out by subjecting the top previously gathered in a container with drilled holes alternately to a vacuum and to vapour under pressure.
The above mentioned thermal treatment is carried out in a discontinuous way and involves a series of drawbacks both as far as cost as well as quality is concerned.
The increase in cost is due to the handling of the tops, to the consumption of motive power and to the high consumptions of steam. In fact, the impossibility of completely fiiling the useful space inside the autoclaves used for the shrinking operation as well as the necessity to have recourse to successive vacuum/steam cycles do affect in a sensible way the steam consumption.
From the qualitative point of view, the discontinuous operation systems in autociaves have the drawback of exhibiting a not altogether complete homogeneity of treatment, as a result of which either poorly annealed and/or humid zones will be met in the top. In any case, the discontinuous systems involve treatment gradients which lead to the formation of defects in the end products of the textile cycle.
In order to obviate the above drawbacks, there have been realized devices for the continuous shrinking of the tops.
These devices, in general, are added after the crimping and determine a considerable increase in the overall dimensions of the machinery.
Furthermore these are rather complex apparatuses both from the point of view of running as well as of the maintenance involved. Moreover, the discharge of the material subjected to a vaporization treatment is not always correct and may cause drawbacks both in respect of the working of the machinery downstream as well as in respect of the quality of the finished product.
The present invention accordingly aims to provide a process for the shrinking of a top of thermically shrinkable fibres, that overcomes or at least mitigates the above mentioned disadvantages.
According to the invention, the top of thermically shrinkable fibres, on leaving a stretchbreaking machine, is subjected to a thermal treatment by humid or saturated steam contemporaneously with a crimping phase.
The process of the present invention for the shrinking of a top of thermically shrinkable fibres is cheap, easy to run and allows the obtaining of a complete and homogeneous treatment of all the discontinuous fibres that form the top.
The process of the present invention may be carried out by feeding into a crimping chamber humid or saturated steam, upstream of the crimping bar and perpendicular to the feed of the top.
To this purpose, the walls of the crimping chamber may be provided with a series of small holes through which the steam is fed to the discontinuous fibres of the top. The holes may be suitably drilled along the walls of the crimping chamber.
The feeding in of the steam is carried out upstream of the crimping bar and preferably within the zone comprised between the crimping bar and the roller at the outlet of the stretch-breaking machine, which feed the top.
The temperature of the steam is preferably higher than 100"C, more preferably from 105"C to 120 C. The treatment time shall correspond to the dwelling time of the top inside the crimping machine and in general will be below 30 seconds.
The process of the present invention may be used on any crimping machine and for all thermically shrinkable fibres. The process will be particularly suited for acrylic fibres, that is for fibres obtained by either wet or dry spinning of polymers containing at least 70% by weight of acrylonitrile or of polymer mixtures in which the total content in polymerized acrylonitrile is greater than 70% by weight.
The process of the present invention does not adversely affect the operational speed and output of crimping machines. In fact, there may be attained working speeds of up to 250 m/min. and an output of up to 400 Kg/hr.
Moreover, the total denier of the top is that usually used in crimping machines, that is up to 40 g/m.
With the process of the present invention, the crimping imparted to the top occurs on the fibres which are in a humid heat condition and, thus, the crimping proves more effective and heat-stabilized with a consequential ease of processing in the successive setting passages, given the excellent cohesion imparted to the fibre. Such an advantage cannot be obtained with the continuous shrinking devices and/or processes of the prior art, in which the shrinking operation occurs downstream of the crimping chamber. Moreover, the process of the present invention allows a drastic reduction in the consumption of steam, due to the small internal volume of the apparatus and to the high packing of the fibre. Due to the small volumes involved, there do not exist problems of thermal inertia during the starting step.
The crimped and stabilized top obtained by the process of the present invention shows a perfect regularity and is placed in gathering containers in a compact and uniform way.

Claims (7)

1. A process for the continuous thermal shrinking of a top of thermically shrinkable fibres, at the outlet of a stretch-breaking machine, by means of a heat treatment with humid or saturated steam, wherein the heat treatment is carried out contemporaneously with a crimping phase.
2. A process as claimed in claim 1, wherein the steam is fed into a crimping chamber downstream of a crimping bar and perpendicular to the direction of feed of the top.
3. A process as claimed in claim 2, wherein the steam is fed in through holes in the walls of the crimping chamber,
4. A process as claimed in any of claims 1 to 3, wherein the temperature of the steam is greater than 100"C, and the time of treatment is below 30 seconds.
5. A process as claimed in claim 4, wherein the temperature of the steam is from 105 to 120"C.
6. A process as claimed in any of claims 1 to 5, wherein the top consists of acrylic fibres.
7. A process according to claim 1 for the continuous thermal shrinking of a top of thermically shrinkable fibres, substantially as herein described.
GB8605724A 1986-03-24 1986-03-07 Process for shrinking thermically shrinkable fibres Expired GB2187481B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
BE0/216449A BE904474A (en) 1986-03-24 1986-03-24 METHOD OF CONTINUOUSLY SHRINKING A THERMALLY SHRINKING FIBER TAPE.

Publications (3)

Publication Number Publication Date
GB8605724D0 GB8605724D0 (en) 1986-04-16
GB2187481A true GB2187481A (en) 1987-09-09
GB2187481B GB2187481B (en) 1989-12-06

Family

ID=3862366

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8605724A Expired GB2187481B (en) 1986-03-24 1986-03-07 Process for shrinking thermically shrinkable fibres

Country Status (4)

Country Link
BE (1) BE904474A (en)
DE (1) DE3609024C2 (en)
FR (1) FR2596072B1 (en)
GB (1) GB2187481B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5718159A (en) * 1996-04-30 1998-02-17 Schneider (Usa) Inc. Process for manufacturing three-dimensional braided covered stent
EP0860526A2 (en) * 1997-02-19 1998-08-26 G.I.B.A. S.p.A. Process and equipment for bulk-texturizing ans simultaneous interlacing of thermoplastic yarns, using heating fluids
US6592617B2 (en) 1996-04-30 2003-07-15 Boston Scientific Scimed, Inc. Three-dimensional braided covered stent

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB837573A (en) * 1956-12-24 1960-06-15 Bancroft & Sons Co J Method and apparatus for crimping textile fibers
GB1259031A (en) * 1968-09-21 1972-01-05
GB1300379A (en) * 1969-07-24 1972-12-20 Rhodiaceta Method and apparatus for preparing a highly springy thermoplastics textured yarn
GB1365975A (en) * 1970-12-07 1974-09-04 Mitsubishi Rayon Co Process and apparatus for continuously relaxing textile yarns
GB1381458A (en) * 1972-03-29 1975-01-22 Allied Chem Process of and apparatus for texturing yarn
GB1534587A (en) * 1975-06-26 1978-12-06 Barmag Barmer Maschf Stuffer box crimping device for thermoplastic yarns

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE466687A (en) * 1943-05-08
US3305897A (en) * 1964-10-28 1967-02-28 Du Pont Crimping process
CH442603A (en) * 1964-10-30 1968-01-31 Lonza Ag Process for the production of crimped fibers from thermoplastically deformable plastics
US3516241A (en) * 1968-10-30 1970-06-23 Asahi Chemical Ind Process for the manufacture of crimped spun yarn
US3628224A (en) * 1969-06-30 1971-12-21 Mitsubishi Rayon Co Process and apparatus for continuously treating manmade filament tows under a normal pressure condition
CA953486A (en) * 1970-03-05 1974-08-27 Goro Ozawa Crimping method and apparatus
NL7113810A (en) * 1970-10-17 1972-04-19
GB1364062A (en) * 1971-08-04 1974-08-21 Ici Ltd Filamentary tow setting apparatus
US4258457A (en) * 1972-12-29 1981-03-31 Phillips Petroleum Company Method for coating and crimping synthetic thermoplastic
DE3010045A1 (en) * 1980-03-15 1981-09-24 Bayer Ag, 5090 Leverkusen METHOD FOR THE PRODUCTION OF HIGH-SHRINKABLE ZIPPERS FROM ACRYLNITRILE POLYMERISATION
FR2499104A1 (en) * 1981-01-30 1982-08-06 Sirs Soc Int Revetements Sol Waste thermoplastic fibres - are garnetted and fed to heated crimping box

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB837573A (en) * 1956-12-24 1960-06-15 Bancroft & Sons Co J Method and apparatus for crimping textile fibers
GB1259031A (en) * 1968-09-21 1972-01-05
GB1300379A (en) * 1969-07-24 1972-12-20 Rhodiaceta Method and apparatus for preparing a highly springy thermoplastics textured yarn
GB1365975A (en) * 1970-12-07 1974-09-04 Mitsubishi Rayon Co Process and apparatus for continuously relaxing textile yarns
GB1381458A (en) * 1972-03-29 1975-01-22 Allied Chem Process of and apparatus for texturing yarn
GB1534587A (en) * 1975-06-26 1978-12-06 Barmag Barmer Maschf Stuffer box crimping device for thermoplastic yarns

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5718159A (en) * 1996-04-30 1998-02-17 Schneider (Usa) Inc. Process for manufacturing three-dimensional braided covered stent
US6592617B2 (en) 1996-04-30 2003-07-15 Boston Scientific Scimed, Inc. Three-dimensional braided covered stent
US7052513B2 (en) 1996-04-30 2006-05-30 Boston Scientific Scimed, Inc. Three-dimensional braided covered stent
EP0860526A2 (en) * 1997-02-19 1998-08-26 G.I.B.A. S.p.A. Process and equipment for bulk-texturizing ans simultaneous interlacing of thermoplastic yarns, using heating fluids
EP0860526A3 (en) * 1997-02-19 1999-09-08 G.I.B.A. S.p.A. Process and equipment for bulk-texturizing and simultaneous interlacing of thermoplastic yarns, using heating fluids
US6029328A (en) * 1997-02-19 2000-02-29 G.I.B.A. S.P.A. Process and equipment for bulk-texturizing and simultaneous interlacing of thermoplastic yarns, using heating fluids

Also Published As

Publication number Publication date
GB2187481B (en) 1989-12-06
DE3609024C2 (en) 1998-01-29
DE3609024A1 (en) 1987-09-24
FR2596072B1 (en) 1988-06-10
BE904474A (en) 1986-09-24
FR2596072A1 (en) 1987-09-25
GB8605724D0 (en) 1986-04-16

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20010307