DE1669451A1 - Process for the production of high strength threads from polyethylene terephthalate - Google Patents

Description

Description of the patent application

IMPERIAL CHEMICAL INDUSTRIES LIMITED, London SW 1,

Great Britain

concerning

"Process for the production of high-strength threads from Polyäthylent he epht halat *.

Priority : 23 Aug 1965 - Great Britain

The present invention relates to the treatment of oriented crystalline filamentary yarns made from polyethyxenterephthalate.

Threaded yarn made of polyethylene terephthalate with a high

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intrinsic viscosity of the order of 0.85 to 1.00 dl per gram have, after melt spinning and drawing under suitable conditions, a high strength of the order of 8 to 10 g per denier at elongation values of 10 to 14 l, but their shrinkage properties are for example 150 ^° C. such that they have a 10 to 14% free shrinkage and a shrinkage force of 0.55 g per denier.

Various heat treatments are known to reduce this shrinkage, for example in a heating furnace or overhead guiding the threads over hot plates, however under such conditions, other properties of the filaments, such as strength, elongation and modulus undesirably decreased.

There is now a method for treating such threads, which have a high strength, proposed without thereby other properties are significantly influenced by the heat treatment at high temperatures and is carried out under precisely regulated conditions.

The present invention provides oriented crystalline filaments of polyethylene terephthalate in which the inherent viscosity of the polymer from 0.85 to 1.00 dl per gram

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and which have the same properties throughout their length, with at least a tenacity of 8 g per denier in the form of a yarn up to 10,000 denier, the yarn having no more than one twist per inch of twist and an elongation of at least 10%, a Shrinkage of less than 8%, a modulus of 2% with a strength of 90 g per denier and a shrinkage force at ISO ⁰ C of less than 0.35 g per denier or a modulus of 2% with at least 65 g per denier strength, when the shrinkage is 5 Hh 0.5% and the shrinkage force is less than 0.50 g per denier.

The stated strength values were determined on an Instron strength tester with a Hess length of 30 and a crosshead speed of 10 g / min. The shrinkage values give the free shrinkage of yarn samples after 15 minutes long treatment in air at 150 ⁰ C on. The shrinkage force is determined ^{at 150 ° C. in a silicone oil.}

The intrinsic viscosity is determined in the usual way by dissolving yarn samples in orthochlorophenol and measuring the outflow times of a 1% solution of the sample and the solvent in a suitable Ostwald viscometer at 25 ° C. This procedure is described in ¹¹ ICI Fibers Limited Technical Information Manual, Section C.2 ".

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The invention also provides a process for the production of high strength threads from polyethylene terephthalate proposed, wherein the intrinsic viscosity of the polymer is 0.85 to 1.00 dl per gram and wherein Filament yarns with a denier value up to 10,000 and with a twist of no more than one turn per inch through Feed devices, thread take-up or take-up devices are supplied, which rotate at previously determined relative speeds, which are the same or slower and wherein the filaments are passed through a heating zone for between 1 and 12 seconds, the heating zone is equipped with heat exchange devices, which consist of a multitude of small particles which exactly at a temperature of + or - 3 ° C within the range of 240 to 264 ° C, i.e. 25 to 1 ° C below the melting temperature of the threads.

In one embodiment of the invention, the threads are allowed to slacken by 3 to * »% as they pass through the heating zone Speeds of at least 300 m per minute and preferably 1000 m per minute can be passed, resulting in dwell times corresponds to from 2 to S seconds. In order to achieve the required treatment times, the threads can be placed on a multiple path through a single heating zone, in one bath or in several baths in series

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AAOORiGiNAL

are arranged. The spam rank in the »heating zone can be due to different regulated relative diameter of the guide wheels or by adjusting the relative speeds of wheels of the same diameter or by a coordination dee diameter and speed of rotation of the wheels or Roll.

When the threads are slackened in the manner indicated, so they are extremely suitable for the production of Objects5 which are provided with coverings, for example those made of PVC or neoprene.

In another embodiment of the invention, the threads are kept under a constant length _s while they are passed through the heating zone at speeds of at least 300 ία per minute »preferably 1000 m per minute, with BehasädXungssseitisn of the order of 5 to 2 seconds are applied · Thread yarn, which is a heat treatment. have been subjected to constant length, have a high modulus and strength values, as they are required for chewing inserts, in particular for V-belts, conveyor belts, ReitVineinlag & n and hoses ₅ such as fuel hoses,

The heat release seals which for the present Procedures are signed and, as far as known, the only ones

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represent suitable means, consist of a mass of fine solid particles, which with the threads in intimate contact and which are brought to the required temperature in a suitable bed of the particles. without it to a melting of the thread material or to a significant influence on other properties of the same comes. The optionally preheated threads are brought near the bed of the solid heated particles or passed through this before they start with the fixed ones Particles are brought into contact. The mass of solid particles can be kept in a flowing state namely by a gas stream, which is optionally heated is and is kept at the required temperature. the required temperature can be maintained by the particles are heated in a bed of the particles and the gas stream itself can also be heated while or before it is passed through the bed of particles,

In the present method, the particles can be used in a suitable Container are heated, which one? with pipes for feeding of the gas is provided or the gas can be introduced through an upwardly directed pipe without it is passed through the wall of the container. When the gas flow is turned on, the particles will go up thrown and held in one movement, and through

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ORIGINAL

Interaction of the gravity of the particles and dee upwards directed gas flow or the gas flow ©.

In another embodiment of the method, the Particles brought to the required temperature in a suitable bed and by gravity directed downwards be brought into contact with the threads. In this embodiment, means are required to convert the particles into bring back the bed. For this purpose, mechanical conveyor systems, or air »or gas conveyors.

When the particles are in a flowable state through a upward flow of gas or air is maintained, a bed of solid particles is created and the particles are kept in .Suspension by the speed of the gas, the particle mass a liquid-like Behavior, so that objects which remain on the surface of the mass of solid particles per se, However, in it rapidly sink down, when the mass of the Particle is not kept in suspension by the gas flow. By such a particle mass kept in the flowable state there is rapid heat transfer to objects that are immersed in the mass.

Suitable Viärmeausteuschvorrichtungen consist of a bed

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from solid particles kept in the flowable state, which can be heated by means of a gas flow or electrically. A flowable mass of solid particles is understood to mean small solid particles which are transported by a gas stream suspended or kept in suspension, which through the particle mass at such rates and amounts is passed through that the particles remain in suspension or move freely.

A bed of solid particles, held in suspension by the velocity of the gas, behaves like one Liquid and objects which would remain on the surface of the bed of solid particles when it was not kept in suspension by the gas stream, the particles will sink rapidly down the bed as they pass through the gas stream can be kept in suspension.

Suitable solid particles to be used for carrying out the heat treatment are made of sand, glass, small balls, small aluminum balls and such other materials that can be deformed to a suitable particle size that is largely uniform Have particle size.

Particles with a cross-sectional diameter of about 1 mm,

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1 * 69451

however, not less than 50 μ are particularly suitable. These particles can be heated by means of heating coils immersed in a bed of such particles or by passing circulating fluids through a suitable dumbbell around the container in which the particles are located. The particles can, however, also be heated by electrically heated elements which are immersed in the particle mass or which form the walls of the container or by other means by which the walls of the container which receives the solid particles can be heated.

Who de the bed? Containers containing solid particles can equipped with devices for introducing and circulating the gas flow, steam or air flow at a certain speed to keep the solid particles in suspension.

The filaments are constant-length through the fluidized bed headed or with a relaxation or extension, what depends on the balance of properties that the Product should own. The dwell time, which is dependent on the denier value, can preferably be between 1 and 12 seconds. With a yarn of 1000 denier, a dwell time of 1 to 5 seconds, preferably from 2.5 to 3.5 seconds,

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suitable »The lead-through lengths through the hot zone can go through Setting the number of runs can be changed, for example by the number of turns, around a roller system in a single bed or by using a number of beds arranged in series.

It should be pointed out that to date only polyester yarns with internal viscosities of the order of magnitude of 0.60 to 0.75 dl / g have been commercially available. With such yarns, which have strength values of 7.5 ♦ 0.5 g per denier, it is possible to reduce the free shrinkage at 150 ^° C. to about 4% and the shrinkage force to 0.30 g per denier without a Loss of strength or modulus occurs in that the yarns are heat-set at constant length at temperatures between 210 and 230 ° C. In PoIyestergarnen of particularly high strength, having an intrinsic viscosity within the range from 0.85 to 1.0 dl / g, is at a Wärniefixierung at constant length at these temperatures, the free shrink and shrink force at 150 · C to ⁰ does not decrease the required value. Un the shrink properties of a high intrinsic viscosity having yarns to reduce has been found that these subjected to heat fixation at a constant length at temperatures above 240 ⁰ C or a Wäremerschlaffung 3 to H% at the indicated temperatures from 2U0 to

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26 * J ° C must be subjected to "

When low shrinkage properties are more important than a certain one
/ Garaimodul, the warmth relaxation method is preferred. However, when yarn modulus is more important, heat set at constant lengths is preferred. In both cases, heat setting at the specified maximum possible setting temperature gives the best results. As far as is known, only a positive heat exchange with the Hasse of the solid particles is possible, preferably with a fluidized bed system _:. drive sufficient temperature control to be able to work economically at the required heat setting temperature within 24 to 1 ° from the yarn melting point «For polyester yarns with an intrinsic viscosity within the range of 0.89 to 1.0 dl / g, it is therefore necessary to use the fluidized bed process in order to obtain satisfactory shrinkage properties for large-scale operations.

The invention is explained in more detail in the following examples. example 1

A 1000 denier yarn sample of polyethylene terephthalate yarn, the one S-twist of 3A turns per inch, an inner one

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bath

Viscosity of 0.90 dl / g, a strength of 8.5 g per denier and an elongation of 10.1%, was heat set at constant length in a fluidized bed under the following conditions.

Thread speed Number of single filaments Number of fluidized beds Lingering stretching applied in the Eett

200 m / min 16 i 2 _S 6 seconds 0%.

The effect of the "heat-setting treatment" on the physical The properties of the yarn are shown in the following table:

denier Physical 5 Firm
speed
g / d Properties of the yarn 3 %
module
g / d ISO ⁰ C
Shrink
fung
% ISO ⁰ C
Shrinkage
force
g / d Bet t emperat ur
⁰ C 1002 Fracture-
load
kg 8, p Stretchy "
speed
% 8 2 13.0 0.55 unfixed 100? 8.8 8.6 ? L0, l ' 80 9.5 0 * 30 220 £ I 979 3.65 8.5 £ 1.0 80 8.0 0.3H 2 «f0 ♦ 1 998 8.3 8.0 i.1.0 6.8 0.30.
• V 260 ♦ J 8.0 10.7

Example 1 also shows ₃ that the shrinkage does not

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8% decreases, wsrai the TempQratui exceeds ⁹ 2 ^ 0 ⁰ C, The

aft nähsrt auah is not the satisfactory value of 0 ₉ 30 grams per denier. This example also shows that with a WSmsfixiexnmg up to constant length at T <ssap'33? Atuj? 3n above 2'iO ° C there is no loss of the module.

When using the yarns as tire inserts, inserts for V-bands, etc., it is important that the textile reinforcement does not shrink during the rubber vulcanization treatment ₉ as this would result in a twisting and loss of the module ©-3. At. When the yarn is used for this purpose, its shrinkage properties must be reduced to a minimum, while at the same time the values of the tensile modulus and strength must be maintained. As can be seen from the example, this is best achieved when using the highest temperatures.

Example 2

The procedure was the same as in Example 1 , but using a relaxation of 3%.

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in the- -

Physical properties of the yarn denier Fracture-
load
kg Firm
speed
g / d Stretchy
Jceit
% %
module
g / d 150 ⁰ C
Shrink
fung
% 150 ⁰ C
Shrinkage
force
g / d Bed emperat ur
⁰ C 1002 8.8 8.5 10.1 82 13.0 0.55 unfixed 1068 8.9 8.4 l «l, 2 66 S, 9 0.16 220 + 1 1036 8.65 8th,"* 1 «*, p 68 5, «» 0.14 240 * 1 1059 8.2 7.8 14.3 68 0.13 260 +; 1

In the manufacture of textile fabrics provided with a covering, it is very important that the yarns of which the basic textile is made have a low and, as far as compatible, no shrinkage at all at the temperature which is used when the elastomer covering is vulcanized and the 120 to 190 ⁰ C. If this is not the case, the fabric becomes puckered and thus prevents the formation of a smooth coating of the elastomer. The requirement for very consistent shrinkage thus suppresses the requirement for high modulus and tensile strength at this end use.

From example 2 it can be seen ₉ that a 3% slackening leads to a lower free shrinkage and a significantly lower shrinking force than with a heat definition

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iiiit constant? Length (Example U _9, however, at the expense of the garnifiodule. The variability of the free shrinkage is also extremely low with this fluidized bed process and is in the order of magnitude of S + 0.5%. For this reason, the changes according to the invention are rapid s slack yarns are particularly suitable for use with textiles to be covered with a covering *

Comparative experiment A

Samples of monofilament yarn made of polyethyleneteil ephth & lat of 1000 denier with an S-twist of 3A turns per inch, as used in Example 1, were treated at constant length and allowed to slacken by 3% during the treatment described, as in the example 2, with the modification that was used instead of the heat exchange through the fluidized bed a driven Viarme roller of 15 cm in diameter, was placed between the advancing and conveying rollers, said warm orphan to temperatures of 220, 2U0 and 260 ⁰ C was maintained -The yarn was wrapped around the heating roller with two turns «,

The properties of the yarn, in particular the strength of the same, were below those as they were due to the

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· Is achieved forming method object of the invention at temperatures of 2uo ⁰ C Mufig damage occurred of the yarn and at 260 ⁰ C occurred some melting of the yarn on "Furthermore, had, in the method, bsi the working with the heating roller, with substantially lower winding speeds are used, namely those below 100 m per minute.

Comparative consumption B

The procedure of Comparative Example A was repeated, with the exception that, instead of the heating roller with a diameter of 15 cm, an air heating furnace 3 1/2 in length was used, with temperatures of 220, 2 HO and 260 ° C. being maintained. The properties of the yarn treated to this whiteness were somewhat better than those in comparative test A, but were still below the values obtained with the method according to the invention. It had to be worked with yarn speeds below 50 m / min and the Garnunterschieden occurring were much larger than it in Examples 1 or 2 of the present description is the case, especially when the free shrinkage sabweichung was hai 5% + 2%.

It is useful to use an adhesive such as a

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To apply a solution of cyanate in methylene chloride to the yarn fixed by means of the same continuous process and immediately after the? Treatment in the fluidized bed and before the yarn is wound up. It I3T important that the yarn to a Tempez "at: ur is cooled below 70 ⁰ C and the tension is released before the Gar-η enters the soaking zone, after which it is dried and wound up.

PATENT CLAIMS:

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Claims (7)

PATENT CLAIM: Oriented crystalline threads made of polyethylene terephthalate, characterized in that the inherent viscosity of the polymer is 0.85 to 100 dl per gram, the yarn being uniform Has properties along its entire length, and the threads in the form of a yarn up to 10,000 denier have a strength of Have 8 grams per denier twisted with no more than two turns per inch, an elongation of at least 10% and one Having a shrinkage of less than 8% and a modulus of 2% at at least 80 g per denier, a shrink force of less than 0.35 g per denier or a 2% modulus of at least 25 g per denier when the shrinkage is 5 + 0.5% and the Very good strength is less than 0.15 grams per denier. 2. Oriented crystalline filaments made of polyethylene terephthalate according to claim 1, characterized in that they are in the form of Rubber reinforcement liners are used for V-belts, conveyor belts., Tire inserts, hoses and textiles, including those that are provided with a covering made of PVC and neoprene. 3. Process for the production of high strength Threads made of polyethylene terephthalate, the inherent viscosity of the polymer being 0.85 to 1.00 dl per gram, 209808/1450 ORIGINAL characterized in that yarns made from these threads with a denier of up to 10,000 and a twist of no more than one turn per inch is fed through conveyors, take-ups or winders, which rotate at previously determined relative speeds, which can be the same or lower, the threads between 1 and passed for 12 seconds through a heating zone equipped with heat exchange devices consisting of a There is a mass of solid particles which, with a temperature deviation of ♦ or - 3 ° C, are within the range from 2 »» 0 to 26H ° C, i.e. 25 to 1 ° C below the »melting temperature of the thread material. 4. The method according to claim 3, characterized in that the threads are slackened by 3 to H% while they pass through the heating zone at a speed of at least 300 m per Minute are passed, so that treatment times of 2 to 5 seconds are available, the tension of the yarn by appropriate Means is regulated. 5, method according to claim I 3, characterized in that the threads are heat set at constant length, passing through the heating zone at speeds of at least 300 m per minute run so that treatment times of the order of magnitude from 2 to 5 seconds can be achieved., 209808/1450 -20-1569451 6. The method according to claim 3, characterized in that the solid particles of the heating zone have a cross section between 1 mm and 50 μ and they are kept in a flow state do it be, / by a heated gas stream, which at the required Temperature with a deviation of j. 1 ° C is kept, φ 7. expired according to claims 4 to 6, characterized in that that the particles are at the required temperature be placed in a suitable bed and by force of vibration naolt are brought into contact with the threads below, whereupon then the particles are returned to the bed by suitable means will. 0. A method according to claim 3 to 6, characterized in that the particles are heated in a bed of the particles and the »gas flow itself before or during the implementation the bed of particles is heated. 9. The method according to any one of claims 3 to 8, characterized that the filaments are preheated before they are brought into contact with the solid particles. 10 «Method according to one of claims 3 to 9, characterized by germline *, that the particles are heated by one of the following means: heating coils that enclose a bed of the particles 209808/1450 are immersed, by circulating heated media, through a suitable jacket, which is placed around a container, in where the particles are located, by electrical heating of the particles by heating elements that are in the particle race are introduced or by the heating elements forming the walls of the container * ■ PATBlTANWXLTi DIrMO H FlNCKE DIPL-INRBOHIl Din. **. ♦ Λ * » : y /