DE2153945A1 - POLYESTER WIRE FOR THE PRODUCTION OF ZIPS - Google Patents

Description

FARBENFABRIKEN BAYER AG

LEVERKUSEN-Bayerwerk \ 8 OCT. 1971

Central area

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Polyester wires for making zippers

The invention relates to dimensionally stable zip fasteners made from polyester monofilaments.

As is known, polyesters can be spun into threads or wires by means of spinning units through fine nozzles. For example, the wires are spun into a hot water bath and then pulled out to several times their original length in order to improve the mechanical and textile-technical properties. To achieve the best possible properties, it is stretched in a certain ratio (about 1: 3 to 1: 6) and in a more or less narrowly defined temperature range (between 80 and 220 ° C). Threads are mostly drawn on heated plates or hot godets, while it is preferred to draw the wires in hot water because of the better heat transfer. The monofilaments produced in this way have average strengths of 20 to 40 Rkm at 15 to 30 % elongation, depending on the stretching ratio. In order to reduce the high boiling shrinkage (measured after 10 minutes in boiling water) of approx. 10 % of these wires, they are then fixed either in hot water, on a heated godet or in hot air. This can be done both under tension and without tension.

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The monofilaments obtained can be used in various fields, such as for the production of ropes and Thaws, filters and sieves or zippers.

In the zipper sector, however, it has been shown that monofilaments with the above-mentioned average Properties are only usable to a limited extent, because in the end, strength and elongation are not that precise arrives, but that other criteria are decisive.

It has now been found that the following can be used for the problem-free processing of polyester wires into zip fasteners Features are important:

1. The molecular weight for which the intrinsic viscosity or intrinsic viscosity J is a measure (determination of the Intrinsic viscosity see W. N. Dawydoff: "Determination, of the molecular weight of polyamides ", VEB Verlag Technik Berlin, 1959, p. 44). Monofilaments with an intrinsic viscosity J = 0.80 - 1.07, preferably 0.82 - 0.92, can best be processed into zippers.

2. The crystallite orientation in the direction of the wire axis, determined from wide x-ray angles! Investigations and stated in degrees, must be between 17 and 26 °.

There is a numerical relationship between the intrinsic viscosity and the orientation angle. It can only be easily process those polyester monofilaments into zippers for which the following applies:

Orientation angle = 8 (4xJ-1),

where the equation is considered satisfied if the measured angle is different from that given by the equation does not deviate from the specified value by more than 2 ° upwards or downwards.

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3. The mean crystallite width in the direction across the wire is 80 to 200 A.

4. The mean fluctuation in the crystallite size in the direction of the wire, indicated numerically by the half width of the small-angle X-ray reflex, may not exceed Reach 0.40 °.

Accordingly, the present invention relates to dimensionally stable zip fasteners made of macromolecular polyester or Copolyester wires, characterized in that the Intrinsic viscosity J of the monofilament is 0.80 to 1.07, the orientation angle of the crystallites within the mono- ( fils is between 17 ° and 26 °, between the intrinsic viscosity J and the orientation angle of the crystallites have the numerical relationship

Orientation angle = 8 (4x J- 1)

applies, whereby the equation is to be regarded as fulfilled if the measured angle differs from that given by the equation Value does not deviate by more than 2 ° upwards or downwards, the mean crystallite width in the direction across the wire 30 to 200 A and the mean fluctuation of the Crystallite size in the direction of the wire, indicated numerically by the half-width of the small-angle X-ray reflection, ' reached a maximum of 0.40 °.

The crystallite orientation is derived from wide-angle x-ray measurements certainly. For this purpose, the azimuthal intensity distribution of the (01O) reflex (2 θ = 17.5 °) measured. After separating the Scattered background of the bell curve by a straight line, the width of the distribution curve at half the maximum intensity

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did determined, and converted into degrees (see L. Alexander "X-Ray Diffraction Methods in Polymer Science", J. Wiley & Sons, Inc., New York, 1969, pp. 198-279).

The mean width of the crystallites in the direction across the wire is also derived from a wide-angle goniometer curve calculated (cf. H. Klug, L. Alexander "X-Ray Diffraction Procedures", Verlag J. Wiley & Sons, Inc., New York, 1954, Pp. 491-538). The crystallite width is determined according to the equation

Crystallite ^{width = ¥}

0.01745 (D ² - I ² ) ¹ ' ² * cos 8.75 °

where W is the wavelength (A) of the X-ray radiation used, D (degrees) the width at half the reflection height and I (degrees) the The width of the reflex is half the height of a reflex of a metallic silicon standard (reflex broadening by the Instrument). The most favorable reflex for polyester is the (010) reflex, its radial half-width according to is determined by the conventional method.

A measure of the variation in the distance between the centers of gravity of the crystalline Areas in the direction of the wire are given by the half-width of the X-ray small-angle meridian reflex. To the A Kratky chamber was used to determine these half-value ranges (cf. H. Neff, "Fundamentals and Application of X-ray Fine Structure Analysis", Verlag R. Oldenbourg, Munich, 1959, pp. 321-325). For this purpose, the underground was under the Scatter maximum separated by a straight line that connects the intensities at 2 θ = 0.35 ° and 2 θ = 1.25 °. From the remaining one Peak was again measured the width of the reflex at half the maximum intensity.

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Polyesters include both homopolyesters made from ethylene glycol and terephthalic acid and modified polyethylene terephthalates to understand, for example, as a glycol component, a compound of the general formula

HO -4 CHg -) - OH

have, where χ is a number between 2 and 8. In addition to terephthalic acid, isophthalic acid, Phthalic acid or hexahydroterephthalic acid can be used.

Monofilaments made from these polyesters can be made dimensionally stable, for example Process zippers if they have the features according to the invention. The resulting The advantages are explained in more detail below.

The production of zippers from synthetic monofilaments has been known for a long time. The wires are in a certain distance by a stamping device wide-pressed or wide-spread · The wire can now e.g. in a Pieces of fabric are woven in. Two pieces of fabric with terminal broadly embossed monofilaments can now be done by means of a Slider are hooked into each other, so that you have a zipper. The wire with the at a certain distance impressed heads can also be formed into a helix. Two of these coils are now mutually into one another caught that they are held together by the embossed heads.

If you now process polyester monofilaments, not the ones above Have required features according to the invention, to zip fasteners, the following difficulties arise: When When the cams are formed, the wire experiences a very high level of transverse stress and bursts open.

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Zippers with burst embossing points are a matter of course unusable. One circumvents this by adding a polyethylene terephthalate with an intrinsic viscosity J of 0.80 to 1.07, preferably of 0.82 to 0.92, is used. This means that the transverse strength increases with increasing molecular weight, because the long chain molecules with With increasing intrinsic viscosity, it becomes more difficult to align it when stretching in the longitudinal direction of the wire can. Some of them are still at right angles to the longitudinal axis of the monofilament and increase with increasing molecular weight Contribution to transverse strength.

This is also indicated by the orientation of the crystals, measured in degrees of angle, in the wire. A large angle with a high intrinsic viscosity means that fewer crystallites lie in the longitudinal direction, while one with a low molecular weight The result is a relatively small angle, which indicates a stronger preferred orientation of the crystallites in the longitudinal direction.

It has also been shown that zip fasteners made of polyester wires with an intrinsic viscosity of 0.80 to 1.07, preferably 0.82 to 0.92, particularly flexible, pliable and Are dimensionally stable if the average width of the crystallites in the direction across the wire is 80 to 200 Å in the monofilaments and the mean fluctuation of the crystallite size in the direction of the wire, expressed numerically by the half-width of the small-angle X-ray reflex, does not exceed 0.40 °.

Zip fasteners made of such polyester wires show their flexibility and suppleness in that they are at a Bending stress immediately jump back to its original position. The dimensional stability can be determined by a test check in boiling water. The zipper is placed in boiling water for 10 minutes and then the shrinkage is reported

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in percent, measured. Usable zippers may shrink less than 1 percent; because the zippers with a heat shrinkage greater than 1% decrease in size, for example after dyeing, after a hot wash or after ironing, so that the zipper hardly gets caught and bursts open at the slightest stress. In addition, the item of clothing into which the zipper is sewn wrinkles after this thermal treatment because the zipper has become shorter.

example 1

A polyethylene terephthalate with a melting point of 256 ° C. and an intrinsic viscosity of 0.85 is spun into a wire using a melt extruder. It is then stretched in a hot water bath at 95 ^° C. to 4.6 times the original length. This is then followed by fixation in hot air, whereby the monofilaments can shrink. They show the following properties (diameter 0.50 cm):

Intrinsic Viscosity: 0.85

Crystalline orientation angle: 20.00 °

Average crystallite width: 86 A.

Crystallite size: 0.36 °.

A monofilament with these characteristics can easily be processed into a zipper that is completely dimensionally stable. Cooking shrinkage after 10 minutes in boiling water <1 %. If, on the other hand, a polyethylene terephthalate with an intrinsic viscosity of 0.65 is used, a crystallite orientation angle of 13.4 ° is measured, a value that can be calculated purely by the formula found

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ο, 65 13, 40 ° 89 A. ο, 39 °

Orientation angle = 8 (4 χ J - 1) Orientation angle for intrinsic viscosity

= 0.65 = 12.8 °

is confirmed. This angle is smaller than claimed according to the invention. Although the average crystallite width is 89 A and the crystallite size are 0.39 °, can be made from polyethylene terephthalate monofilaments with these properties Do not use zippers because the wires constantly burst during processing. There were 100 stamps Counted 30 cracks. Here again summarized the properties of these bad monofilaments:

Intrinsic viscosity:

Crystal orientation angle:

Average crystallite width:

Crystallite size *:

If you want a polyethylene terephthalate with an intrinsic viscosity of more than 1.07, e.g. 1.10, this can no longer be spun into wires because of its high viscosity to process.

Example 2

A polyethylene terephthalate with a melting point of 256 ⁰ C P and an intrinsic viscosity of 0.90 is spun in a melt extruder. It is then stretched to 4.8 times the original length in a hot water bath at 95 ° C. This is then followed by fixation in hot air, whereby the wire can shrink.

The following properties were measured;

Intrinsic viscosity: crystallite Average crystallite width: Crystallite size:

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O, 90 20, 60 ° 98 X O, 35 °

A wire with these properties can be processed into a zipper without any problems. It shows no cracks, is very soft and pliable and shows a shrinkage of <1 % after a residence time of 10 minutes in boiling water.

If, on the other hand, polyethylene terephthalate wires are used, they do have an intrinsic viscosity of 0.90, but due to poor spinning or improper aftertreatment the Do not have the claimed properties, the result is zip fasteners that are not dimensionally stable.

For example, the following properties were measured:

Intrinsic viscosity: 0.90

Crystalline orientation angle: 29.20 °

Average crystallite width: 47 X

Crystallite size: 0.50 °

It can be seen that the formula we found Orientation angle = 8 (4xJ-i)

is not fulfilled, because then a crystal orientation angle would have to be of 20.8 °. In addition, the mean crystallite width of 47 A * is too small and the mean fluctuation the crystallite size, indicated numerically by the half-width of the small-angle X-ray reflection, too large at 0.50 °.

A zipper made from these monofilaments shows in boiling water has a boiling shrinkage of 5%. The zipper proves to be unusable because the cams close when they are closed only z. T. get caught and then burst at the slightest tensile stress.

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Claims (1)

Claims Dimensionally stable zip fasteners made of macromolecular polyester or copolyester wires, characterized in that that the intrinsic viscosity J of the monofilament is 0.80 to 1.07, the orientation angle of the crystallites within of the monofilament is between 17 ° and 26 °, between the intrinsic viscosity J and the orientation angle of the Crystallize the numerical relationship Orientation angle = 8 (4x J- 1) applies, whereby the equation is to be regarded as fulfilled if the measured angle differs from that given by the equation. This value does not deviate by more than 2 ° upwards or downwards, the mean crystallite width in the direction across the wire 80 to 200 A * and the mean fluctuation in crystallite size in the direction of the wire, indicated numerically by the half-width of the small-angle X-ray reflection, maximum 0.40 ° reached. Dimensionally stable slide fasteners according to claim 1, characterized characterized in that the intrinsic viscosity of the monofilament is 0.82 to 0.92. Dimensionally stable zip fasteners according to claim 1, characterized in that the monofilaments are made of polyethylene terephthalate exist. Le A 14 o56 - 10 - 309818/0984