DE2264819A1 - FIBER CLOTH AND ITS USE AS ELECTRICAL INSULATING MATERIAL - Google Patents

Description

The invention relates to a naphthalate polyester fiber containing Cloth and its use as an electrically insulating material.

Fibers made from naphthalate polyester that pass through Implementation of naphthalene - ^, 6-dicarboxylic acid with ethylene glycol have been obtained as industrial materials such as rubber reinforcing materials Because of their superior mechanical and thermal properties compared to fibers made from a polyethylene terephthalate which have been used for a long time (U.S. Patent 3,616,852).

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In Japanese patent application 7 972 13o (Japanese Pat. Rep. Referenced in Derw. 1971 no. 35 threads are described with improved elongation, polyethylene-2,6-naphthalate or polyethylene-2,6-naphthalate copolymerized with a content were obtained of less than 15 mole # a third component. The intrinsic viscosity of this polyester above o, 3 at 35 ⁰ C in a solvent mixture of phenol and o-dichlorobenzene.

However, it was believed to be the common naphthalate polyester fibers for use in fields where knitted, woven or non-woven fabrics made from them Fibers are used at high temperatures, especially in the field of electrical insulation materials, are unsuitable. This is mainly because these naphthalate polyesters have low elongation and show a decrease in toughness at high temperatures.

The object of the invention is to provide cloths containing naphthalate polyester fibers which are suitable for electrical insulating materials, have good mechanical properties and good dyeability and heat resistance.

According to the invention, a fiber cloth is provided, which is characterized in that a naphthalate polyester with a content of at least 85 mole # ethylene-2,6-naphthalate units and having an intrinsic viscosity of o, 45 to l, o using a spinneret with a cross-sectional area of 0.049 to 3.14 mm ² per hole at a spinning temperature according to the following equation

28.6 PlJ ^{+ 501} ' ⁴ = ^T = ³⁵ ' ⁷

wherein the spinning temperature T ⁰ C and £ rjj the inherent viscosity of the polyester mean is melt spun and the filaments extruded at a rate of 3ooo to 12 m per minute ooo be recorded.

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22ΘΑ819

A spinning temperature is advantageous accordingly the following equations

28.6 / fr / + 301.4- ^ T * 35.7 BfI + 279.3 T = (73.8 ßrf - 88.6) \ fl + 331.6

applied, where T is the spinning temperature in ° C, J / q / is the intrinsic viscosity of the polyester and A is the cross-sectional

Specify the area in mm per hole in the spinneret. Favorably becomes a draw ratio according to the following equation

-7.43 x 10 " ⁵ W + 2.37 = log D £ 2.27 | / T ~ + 1.98

applied, where V / is the take-up speed in m each Minute, D the stretching ratio and A the cross-sectional

P.
mean range in mm per hole of the spinneret.

The fibers used in the fiber cloth according to the invention have greater toughness, strength and dyeability, a higher melting point and a lower decrease in strength at high temperatures than the usual Naphthalate polyester fibers.

The threads, fibers or yarns in the fiber cloth are advantageously not stretched.

In particular, a fiber cloth is provided according to the invention, which is characterized in that it is by 7 / heat treatment of a fiber cloth that is mainly made of Threads, fibers or yarns made from a haphthalate polyester with a content of at least 85 mol # ethylene-2,6-naphthalate units and with an intrinsic viscosity of ο.45 to l, o

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where the fibers have a diffraction intensity ratio (R) between a Bragg reflection angle 2Θ = 18.7 and 2Θ = 15f6 °, determined by the X-ray diffraction method, im Range greater than 1.73 and up to 5, ο own at one Temperature not lower than 2o5 ° C but below the melting point of the cloth under conditions which are the following Equations

T - 205 S 7Oe " ^{2 l0S} 10 *
T. Tm i -70β- ² <* - ^{1ο &} 10 *>

where T is the heat treatment ^{temperature in 0} C, t is the heat treatment time in seconds and e is the base of the natural logarithm.

This pasertuch according to the invention is particular useful as an electrical insulating material.

When the above fiber cloth is used as an electrical insulating material, it is advantageously used with impregnated with a varnish.

A special embodiment is an electrically insulating material from the fiber cloth according to the invention, which consists essentially of threads, fibers or yarns of a naphthalate polyester with a content of at least 85 mol $ ethylene-2,6-naphthalate units with an intrinsic viscosity of o, 45 to l, o, where the threads, fibers or yarns have a diffraction intensity ratio (R) between a Bragg reflection angle 20 = 18.7 ° and 29 = 15.6 °, determined according to the X-ray diffraction method, in the range of more than 1, 73 up to 5, o own. The fibers used here are

509 8137 089 2

according to the In the DT-PS (patent application P 22 6o 778.9-

43) is obtained.

The mentioned intrinsic viscosity (intrinsic viscosity •) is obtained from the viscosity of the polymer obtained by using a solution of the polymer in a mixture of phenol and o-dichlorobenzene in the ratio 6: 4 was measured at 35 ⁰ C. If the intrinsic viscosity of the haphthalate polyester exceeds 1.0, its melt viscosity becomes excessively high, making melt spinning difficult. If the intrinsic viscosity is less than 0.45, the fibers obtained do not have the desired good properties.

The most essential feature of the fibers used in the cloth according to the invention lies in their new crystalline structure, which by a diffraction intensity ratio (R) in the range of more than 1.73 up to 5 _t oo between a Bragg reflection angle 20 = 18, 7 ° and 20 = 15.6 ° in the diffraction intensity distribution curve in the equatorial direction, determined by the X-ray diffraction method.

In the accompanying drawing is Pig. I a graphic Representation showing the diffraction intensity distribution curves in the equatorial direction of the liaphthalate polyester fibers according to the invention and more commonly show naphthalate polyester fibers obtained by the X-ray diffraction method were obtained. The Pig. 2 shows stress-elongation curves of the naphthalate polyester fibers according to the invention, common naphthalate polyester fibers and polyester fibers with an R value of 1.73 or less.

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Pig. 3 is a graph showing the relationship between the heat treatment temperature and the heat treatment time of woven sheets according to the invention.

The conditions for determining the diffraction intensity curve, as in Pig. I shown were the following:

Filter: nickel filter 35 kV, 2o mA Current: 0.15 mm 0 Diffraction slit: 1 ° Litter slot: 0.4 mm Receiving gap: 1,542 a Wavelength A:

In Fig. 1, curve 1 shows the diffraction intensity distribution curve of the fibers used in the towels according to the invention, and curve 2 shows the diffraction intensity distribution curve of conventional naphthalate polyester fibers. Curve 3 shows the diffraction intensity distribution curve of amorphous naphthalate polyester fibers.

The diffraction intensity ratio (R) between the Bragg reflection angle 2 9 = 18.7 ° and 2 θ = 15.6 °, as ea is applied here, is calculated according to the following equation (1):

_{R =} Icl8.7 ° - Ial8.7 °
"Icl5.6 ° - Ial5.6 °

° and Icl56 °

where Icl8.7 ° and Icl5.6 ° are the diffraction intensities (height of the peak in the curve) at the Bragg reflection angle of 20 = 18.7 ° and 2Θ = 15.6 ° in the X-ray diffraction intensity distribution curve of the fibers and Ial8.7 ° and Icl5.6 °

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20 = 18.7 °, and 2Θ = 15.6 ° indicating the diffraction intensities of amorphous fibers "at the Bragg reflection angle in the diffraction intensity distribution curve.

As can be seen from Fig. 1, the usual naphthalate polyester fibers (Curve 2) a high peak at a Bragg reflection angle 2Θ = 15.6 °, but practically absent a peak at 2Θ = 18.7 °. That is why they have polyester fibers a diffraction intensity ratio (R) of about 0.1. In contrast, those in the towels according to the invention used naphthalate polyester fibers (curve 1) a pronounced peak at 2Θ = 18.7 ° and a diffraction intensity ratio (R) of about 3.0, which is considerably higher than conventional naphthalate polyester fibers.

Due to their new crystalline structure, the fibers used in the towels according to the invention retain one sufficient strength

of at least 4.4 g / den and have a higher elongation than the usual fibers. When the strength of the fibers is expressed as T (g / d) and their elongation is expressed as E (#), the fibers have a toughness expressed by T χ ί E 'of at least 21.5, and the value E is more than $ 11 up to $ 4o. The usual naphthalate polyester fibers having an R value of, for example, about 0.12 have a tenacity of about 21 or less, and it is impossible to increase their strength without a decrease in elongation.

The naphthalate polyester fibers used in the towels according to the invention show a second yield point in their stress-elongation curve. It can be seen from Fig. 2 that the stress-strain curve 1 of the naphthalate polyester fibers used in the towels according to the invention is two

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Show yield strengths at A and B. Point A is the primary yield point and point B is the secondary yield point.

In contrast, the stress-strain curve shows 2 of the usual naphthalate polyester fibers and the stress-strain curve 5 of naphthalate polyester fibers with a R-value of at most 1.73 just a yield point.

Due to their new structure, the crystalline Naphthalatpolyesterfasern far higher melting points than the usual Naphthalatpolyesterfasern used in the wipes according to the invention, which, typically 28o ° C be at least 275 ⁰ C for at least have.

The “melting point ¹¹ given here is the temperature at which an endothermic peak occurs in the DSC curve, which was determined with a 8.5 m sample weight at a heating rate of 10 ° C./min using a Perkin-Elmer tester.

In addition, the pastes used in the towels according to the invention have the advantage that they at most show a small decrease in strength at high temperatures. Those used in the towels according to the invention Pasers also have superior light stability and dyeability compared to the usual naphthalate polyester fibers.

The dye exhaustion of the usual naphthalate polyester fibers with disperse dyes is a maximum of $ 25, while in the case of the naphthalate polyester fibers contained in the towels according to the invention they are in the order of magnitude of at least 4o #.

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The dye exhaustion is determined in the following way: The sample fibers are dyed with a dye bath, which is $ 4 (based on the weight of the fibers) of the disperse dye Dispersol Fast Scarlet B and 0.5 g / l of a dispersant at 100 ° C for 9 minutes, the ratio of the fibers to the dyeing liquid being adjusted to 1: 10o. To 2 cur the after dyeing

■ 3 ben remaining liquid are added 2 cm of acetone and the mixture to 5o cm using an aqueous solution of acetone (ratio of acetone to water 5o: 5o) diluted. The optical density (OD) of this solution was determined with a spectrophotometer. The dye creation is given by the following equation (2).

ODp

Color off creation ($) = (1) x loo (2)

0D _B

where OIU and OD-g are the optical densities of the remaining Liquid after staining or dye solution.

If the R value of the haphthalate polyester fibers is less than Is 1.73, the melting point does not rise, and there is no improvement in impact resistance and fatigue resistance on.

Baphthalate polyester fibers with an R value higher than 5, o cannot be obtained.

In addition to the above properties, the naphthalate polyester fibers contained in the towels according to the invention have high chemical resistance, good dimensional stability against heat and stress, high initial Young's modulus and low moisture content.

The titer value of the fibers used according to the invention is 0.5 to 100 den / thread.

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- Io -

The yarns used in the towels according to the invention can be twisted or untwisted are present. A stretching of the fibers or threads can impair their beneficial properties occur, and therefore the pasers should not be stretched. If desired, the fibers can be heat treated or be shrunk.

Since the pasers contained in the pasertuch according to the invention have a greatly improved toughness and superior Heat stability, colorability and resistance to damp heat can have various disorders, for example the appearance of puffs or the reduction in strength during processing of the fibers, for example be avoided in weaving or knitting operations. Thus, these fibers result in textile objects that are valuable for Craft and industrial applications are where heat resistance is required. Examples of applications of the Cloths according to the invention because of their good heat resistance and dyeability are work clothes and carpets or blankets for use under high temperatures, and because of their good heat resistance and chemical Resistance are application examples of gas filters for high temperatures. They are especially valuable for electrical Insulating materials due to their low moisture absorption. Furthermore, these cloths are valuable for painting canvas or filters for hot water due to their good resistance to moist heat. You can also use Use of their good thermal insulation properties as Thermal insulation materials are used.

The fiber cloths according to the invention can easily be produced by weaving, knitting or mushrooming processes in a conventional manner will.

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- ii -

The appearance and handling properties of the fiber cloths and nonwovens obtained are similar to those of other synthetic fibers comparable to cloths.

The naphthalate polyester fibers or threads can be made into woven sheets of desired texture, for example Linen fabrics, twill fabrics or satin fabrics, knitted or crocheted fabrics such as circular knitted fabrics, or non-woven fabrics Cloths are processed

The stage in the manufacture of non-woven cloths can be connected to the spinning stage. The fiber cloths or fleeces can be woven, knitted or mixed-woven or mixed-spun type. They can also be applied to films or papers to form a laminate be piled up.

These fiber cloths or nonwovens then undergo a treatment stage, such as boiling in a loop, roller drying or heat treatment. Of these, the heat treatment has a particularly great influence on the properties of the fiber cloth obtained and the properties of the same in the subsequent processing stages, i.e. Shrinkage, flatness and dimensional stability against heat.

The heat treatment conditions are defined by the heat treatment ^{temperature (T 0} C) and the heat treatment time (t in seconds) and it was found that the effective warning treatment temperature according to the invention is not lower than 2o5 ° C, but below the melting point of the fibers. Extensive research has been carried out on the heat treatment time at various temperatures. It was found that by

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Heat-treating the fiber cloth under conditions satisfying the following two equations (4) and (5), a cloth can be obtained from naphthalate polyester fibers, which are superior in heat resistance and mechanical strength and also shows flatness, dimensional stability to heat and low shrinkage and the one has a uniform texture and is particularly suitable as an electrical insulating material:

T = 205 £ 70e ~ ^{2 los t} 10 (4)

T = Tm £ -70e- ^{2 (4} " ^lo 6i0 ^t) (5)

where e is the base of the natural logarithm.

Referring to Fig. 3, the relationship between the heat treatment temperature and the heat treatment time shows the hatched area surrounded by curves (I) and (II) corresponding to equations (1) and (2) Part of a combination of heat treatment temperature and heat treatment time, which are closely related to the Properties of the heat-treated cloth, d. H. Dimensional stability when exposed to heat, stability, Shrinkage and flatness.

If this relationship between heat treatment temperature and heat treatment time is not satisfied, d. that is, when the relationship is out of the parts shown by hatching, the properties are of the heat-treated cloth is not satisfactory for practical use.

That of the heat treatment while meeting the temperature and time requirements given above subjected to heat-treated fiber sheet has improved thermal dimensional stability, shrinkage and flatness of the fiber cloth. Therefore, in the received

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Cloths and varnishes are uniformly impregnated. If the cloths are cut into the shape of ribbons, it is easy to cut them so that they have a straight edge.

The heat treatment carried out under the conditions of equations (4) and (5) can be applied using known devices, for example a web dryer (heat treatment device of the blast furnace type or a roller-type heat treatment device). The heat treatment can be either under Tension or allowing limited shrinkage. Because the ijaphthalate polyester cloth allows limited shrinkage on heat treatment, while exhibiting reduced toughness, should the shrinkage preferably to not more than 15% the original length may be limited. If the value exceeds 15%, the above can be used Benefits are not obtained. The above heat treatment can be carried out continuously in the course of processing of the fibers, for example weaving or lye, or before or after the conversion of the fibers into the end product, for example electrical insulating materials.

The naphthalate polyester cloths and nonwovens according to the invention have sufficient heat resistance compared to the usual fibrous electrical insulating materials of quality B or F and have far superior mechanical properties and processability. Therefore, they contribute to the small size and light weight of the equipment and can be used in F requirement machines.

Attempts have been made to produce naphthalate polyester cloths impregnated with a varnish that are flexible,

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flexible and heat resistant to an extent of grade B or F, and these properties even under humid conditions maintained to a sufficient extent. It was found that such naphthalate polyester cloths are obtained can be if the naphthalate polyester cloths with a varnish of alkyd, polyurethane, epoxy, acrylonitrile or silicone type and even heterocyclic type heat resistant paints either alone or can be impregnated in combination.

The naphthalate polyester cloths impregnated with the lacquer have superior mechanical properties, i. great tensile strength, Young's modulus, breaking strength, tear strength and flexural strength, and also good thermal properties and dimensional stability, and show stable electrical properties over a wide temperature range. Furthermore, the naphthalate polyester cloth has sufficient resistance to various Paints, insulating oils, difluorodichloromethane, cooling oils, various organic solvents and plasticizers. A fiber-containing insulating material can be obtained by a suitable choice of a varnish according to the application, which is far cheaper than the usual cloths impregnated with varnish. Furthermore, this has fibrous Insulating material Handling and processing properties that are the same or better than conventional materials are. The fibrous cloths impregnated with lacquers obtained according to the invention are also and can be compared to the usual cloths impregnated with lacquer with heat resistance in area B or F as electrical insulating materials with far better punctures in terms of mechanical properties, the processing ability, the quality and the quantity, which can be supplied can be used.

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The electrical insulating materials according to the invention can be used as cloths, cloth tapes, cloth tube or -Covers in the form of naphthalate polyester fibers alone or in the form of laek-impregnated cloth goods, lacquered Cloth tapes, lacquered cloth tubes or coated pre-preg are used in the form impregnated with a lacquer will. The electrical insulating materials according to the invention can also be used as laminates or as others processed articles by bonding or fusion bonding using an organic material such as Films, or an inorganic insulating material such as glass, asbestos, mica can be used. You can also used in other fields with the incorporation of various antioxidants or fire retardants will.

The fibers can be contained in fiber cloths according to the invention in the form of mixed yarns with other types of fibers be, whereby these substances by e.g. mixed interweaving,. Interweaving or mixed spinning can be obtained.

In addition, heat resistance, flame resistance and Young's modulus of the naphthalate polyester fibers of the present invention can be improved when the naphthalate polyester fibers with aromatic polyimide fibers, aromatic Polyamide-imide fibers, aromatic polyamide fibers, fluoropolymer fibers, glass fibers, carbon fibers or metal fibers blended or blended with other low-melting fibers or heat-fused.

The following examples are provided for further explanation the invention. The diffraction intensity distribution curve in the equatorial direction according to the X-ray diffraction method, the stress-strain curve, the melting point, the melting point under constant length, the resistance to moist V / poor, resistance to dry heat, dye depletion and flame retardancy were determined according to the following procedures:

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ZZD40

X-ray diffraction determination

Filter: nickel filter
Current: 35 KV, 2o mA
Diffraction slit: 0.15 mm 0
Scatter slot: 1 °
Aufnähmespalt: 0.4 um
Wavelength, - ^: 1.542 Ä

Stress-strain curve

Length of the sample: 20 cm

Pull speed: Ioo76 / min at 25 ⁰ C and a relative humidity (RH) of 65 $

In the breaking strength obtained in the stress-strain curve, a decrease in the titer due to the increase in the elongation is not corrected.

Melting point

The melting point of the sample fibers (sample weight: 8.5 mg) was determined by means of a calorimeter with heating at a rate of 10 ° C./min. The sample was in the free state during the determination and the temperature at which the endothermic peak occurred was read from the obtained DSC curve.

Melting point, determined with a constant length of the fibers

The same determination of the melting point as above was carried out, except that the sample fibers were kept at a constant length during the determination.

Resistance to damp heat

The specimen was immersed in water for 6 hours without limitation in length in one

The specimen was placed in water and heated at 15o C

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closed vessel (autoclave) and the strength retention of the specimen was determined.

Resistance to dry heat

The specimen was treated at constant length in a hot air bath at 15o, 23o and 25o ° C for 60 minutes and the strength retention of the specimen was determined.

Dye exhaustion

Disperse dye: Dispersol Fast Scarlet B, $ 4, based on the weight of the fiber. Dispersant: 0.5 g / l
Ratio of good to liquid: 1: loo Coloring temperature: loo ° C
Staining time: 90 minutes

The sample fibers were dyed under the above conditions. Follow up to 2 cm of the remaining liquid 2 cnr acetone were added to the dyeing and the solution was diluted with an aqueous solution of acetone / ytesser in diluted in a ratio of 5o: 5o. The optical density (OD) of the solution was determined using a spectrophotometer measured and the coloring off creation from the following Calculated equation:

^0D R

Dye depletion (#) = (1 - ^ jp x loo

where ODj> and OD _{B are} the optical densities of the remaining liquid after staining and of the staining liquid before staining, respectively.

! "5 1"

Flame resistance

Number of ignitions: ASTM D 123o-61 Limiting Oxygen Concentration Index (LOI):

ASTM D2863-7O

Manufacturing example

The following example describes the production of a polyethylene-2,6-naphthalate thread, which is used in the Fibers according to the invention can be used.

A polyethylene-2,6-naphthalate with an intrinsic viscosity of 0.645 was obtained at a spinning temperature of 315 ° C. through a spinneret with circular spinning orifices each with a diameter of 0.4 mm and a cross-sectional area of 0.156 mm melt-spun and the extruded filaments were taken up at various take-up speeds. The physical properties of the fibers obtained are given in Table I.

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Table I.

Trial no.

(Comparison)

Recording speed (m / min) looo 3ooo

Stretch ratio 145 47 ο

Titer / filament (den) 9.64 2.91

Firmness (g / den) 2, o3 5.64

Elongation (#) 173 23.5

Toughness (g Wden) 26.7 27.5

Young module (kg / mm) 5oo 138o

Shrinkage in it-.

dendes Y / ater (#) 25, ο 2, ο

4ooo
62o
2.22
6.34
18.7
27.4
16oo

2.0

5ooo 765 1.79 6.78 11.6 23.1 175o

2.0

Heat resistance

(Strength washer
attitude) [fo) Hours. thread
melt
liability 78 , 5 77.6 74.6 humid 15o ° C χ 6 Hours. thread
melt
liability 76 ' ⁶ 74.9 72.7 dry 25o ° Cx 1 75.8 49 , 6 56.1 58, o Dyes
creation (#) o, o58 4, 56 4.47 4, o9 R value ( ⁰ C) 267, o 281.4 284.7 29o, 5 DSC melting point

DSC melting point, determined under constant length ( ⁰ C)

273.1

286.4

289.7 293.6

Trial # 1 refers to fibers with an R-value less than 1.73 for comparison during trials Nos. 2 and 4 relate to fibers according to the invention.

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example 1

A polyethylene-2,6-naphthalate having an intrinsic viscosity of o, 64 wvirde at a spinning temperature of 315 ⁰ C through a spinneret having 24 round orifices each with
melt-extruded with a diameter of 0.27 mm and with
recorded at a speed of 2,000 m / min or 3,000 m / min. The physical properties of the fibers obtained are shown in Table VII.

Tabel Experimental
Mr. II 1
(Comparison) 2 Recording speed
speed (m / min) 2ooo 3ooo Stretch ratio 17o 255 Titer / pad (den) 2.97 1.98 Firmness (g / den) 2.64 5.12 Strain (#)
Tenacity (g "if ^ den) 9o, 8
25.1 3o, 3
28.2 Young modulus (kg / mm) 68o 135o Shrinkage in boiling
Water (#) 37.3 2.1 R value o, 13 4.68 Melting point ( ⁰ C) • 271.0 279.8

Experiment no. 1 is used for comparison.

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These fibers were twisted, roll sized lind woven and woven according to an ordinary method Cloths with a density of 72 χ 31 yarns / 2.5 cm and received a width of 101 cm. The cloths were hung in hot water and leached, dried and with 235 ° C at a speed of 20 m / min, all in one 15 m long pin stenter frames, heat-treated. The physical properties of the woven towels are can be seen from Table III (experiments no. 3 and 6).

Table III

Experiment no. 3 1 4th 180 5 6th 7th 8th Fibers from Ver 170 search no. 2 tensile strenght 110 13th (kg / cm2) 80 Ί3 chain 740 740 790 530 shot 75-95 730 680 700 510 Tensile elongation (%) 70-90 1.8 chain 1.7 25th 27 17th 16 shot "31 35 19th 26th Tensile elasticity 1.2 (kg / cm2 χ 103) 1.1 0.4 chain 0.5 16 - 15th 16 15th shot 12th 11 13th 12th Elmendorf-Reiss- 0.1 strength (kg) 0.1 chain 10.2 0.8 < 0.9 < 0.7 < Q, 8 < shot bad 1.0 < 1, K o, 9 < 1.0 < Shrinkage in dry heat 30.5 (250 ° C χ 1 hour) bad (%) 1.7 2.2 2.0 2.3 Flatness Well Well bad Well (observed with 205 bare 5 Eye) Heat treatment 235 conditions 45 Temperature ( ⁰ C) 270 235 275 235 Time (seconds) 10 45 1200 45

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Experiments 3, 4 and 7 are used for comparison. Trial No. 8 shows the results after leaving the cloth at 23o C for 30 days using a gear aging tester was treated.

The physical properties of one made of the fibers woven cloths made by Experiment No. 2 were determined for varying heat treatment conditions; the results are given in Table III.

The woven cloth of Experiment No. 6 was heat deteriorated in air at various high temperatures and on Part of the result obtained is shown in Table III al3 Experiment No. 8.

The above results show that these cloths are satisfactory as heat-resistant materials can be used in the range of quality P (155 ° C),

Example 2

Each Paser of experiments No. 1 and 2 according to Example 1 was mixed with 15 wt twisting, roll sizing, and drawing-in were conventionally carried out to form woven fabrics having a density of 72 31 yarns / 2.5 cm and a width of 10 cm. The woven towels were hung in hot water and rinsed. After drying, the sheets were heat-treated at 235 ⁰ C at a rate of 2o m / min in a pin tenter of 15 m length.

The properties of the woven fabrics obtained are from Table IV below.

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Table IV

Trial no. 9 1 Io Easers from experimental
No. 2 tensile strenght
(kg / cnr) 125 chain 115 750 shot 690 Tensile elongation (%) 55-65 chain 45-50 25th shot 33 Tensile elasticity
(kg / cm ² χ 10 ^) 1.0 chain Q-, 8th 12th shot 11 Elmendorf Reissfestig
speed (kg) 0.3 chain 0.2 1.0 shot 1.1 « Dry heat shrinkage 18.1 (25O ⁰ C χ 1 hour) Example 3 1.4

The same naphthalate polyester cloth as in Experiment No. 6 of Example 1 was coated with a varnish (Copolymer of methylphenylsiloxane and an alkyd resin, d. H. an alkyd-modified silicone varnish) and the resin-impregnated Cloth dried at 120 ° C for 7 minutes. It was then baked at 200 ° C. for 26 minutes. The amount of the varnish impregnated was 2.7 times the weight of the base cloth. A woven cloth was used for comparison Cloth made of polyethylene terephthalate threads (5o den / 24 threads)

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used as a base cloth and impregnated and dried under the same conditions as above. The properties the two cloths were compared. The results are given in Table V. Results from the values it turns out that the cloth of the present invention is sufficient as a heat-resistant material within the range of Quality F (155 ° C) can be used while with no favorable results were obtained with the comparison cloth.

Tabel V 210OC Polyethylene tere-
phthalattuch properties Naphthalate polyester
cloth Days (Comparison) Initial after 420 Initial after 210 C.
worth χ 7 days worth 'χ 7 19th 490 150 tensile strenght
(15 now width,
kg / cm ^) 680 800 38 5 Tensile elongation
(15 now width,%) 28 6th 10 ⁴ <completely
dig ge
harms Schopper bending
strength
(multiple) 10 ³ < 9x10 ^ 8 <1.3 Mullen-Bruchfe-p
stiffness (kg / cm) 8 < 53 Volume resistance
(Ohm-cm) j 5.1x10 ^ 2, 60 0 dielectric
Breakthrough
stiffness (KV / mm) 60

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Example 4

A polyethylene-2,6-naphthalate with an intrinsic viscosity of 0.58 was at a spinning temperature of 303 ° C through a spinneret with 48 round openings each with melt-extruded with a diameter of 0.4 mm and in various Extensively twisted to achieve coherence · Then the twisted threads were taken at a take-up speed of 3,000 m / min using a draw ratio of 653. The properties of the The threads obtained are given in Table VI.

Table VI

Experimental
No. 11 12th 13th Insolvency
size * (number / m) 0 4th Io Titer / pad (den) 5.2o 5.22 5.24 Firmness (g / den) 5.21 5.18 5, o9 Strain (#)
Tenacity (gf ^ den) 2o, 5
25.5 19.8
25.1 18.3
21.7 R value 4.55 4.55 4.36 Melting point ( ⁰ C) 28o, 6 28o, 4th 28o, 7

* according to the procedure of British patent specification 924 o89

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After the yarns had been twisted, a tube with an inside diameter of 2.0 mm was woven therefrom using 24 weft bobbins. The interwoven strands gave a tube free from puffs, and the weavability was good. The tubes could be used satisfactorily as heat-resistant materials in the range of quality P (155 ^{° C.).}

Example 5

A polyethylene-2,6-naphthalate with an intrinsic viscosity of 0.638 was at a spinning temperature of 308 ° C through a spinneret with 48 round openings each with melt-spun with a diameter of 0.4 mm. A predetermined speed was applied to the extruded filaments issued by a pair of Nelson rollers and sucking, spreading and dispersing through an air jet nozzle they were collected to form a web or layer of threads. The web was used to form a nonwoven Tuches needled. The properties of the yarns and the non-woven fabrics obtained are as follows Table VII listed.

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Tabel Experimental
No. VII 15th 16 Recording speed
(m / min) 14th
(Comparison) 3ooo 4-OOO Titer (den) 2ooo 2.28 2.19 Firmness (g / den) 2.24 5.32 6.14 Elongation ($) 2.54 25.1 19.2 Toughness (g "f ^ den) 96.4 26.7 26.9 Shrinkage in boiling
water • 24.8 1.9 1.8 R-Ytert 44.5 4.45 4.38 Melting point ( ⁰ C) o, o8 28o, 9 285, o Properties of the non- "268 woven cloth

Shrinkage range (dry heat at 175 C) Heat resistance

(Toughness retention)

3.4

3.2

Moist 150 " C. X 6th Hours. Threads 79 , 5 78 , 4 Dry 250 ° C. X 1 Hours. melt 77 , 4 75 , 6 liable

Trial No. 14 is used as a comparison for fibers with an R-value of less than 1.73. Experiments nos. 15 and 16 demonstrate fibers according to the invention.

50981 3/0892

Claims (5)

DR. E. WIEGAN DI PL-1 NG. W. NIEMAN N DR. AA. KÖHLER DIPL-ING. C. 3ESNHARHT MÖNCHEN H / MBUK <3 TELEPHONE: 555476 \ t 8000 MQNCHEN 2, 9 · Sept. 1974 TELEGRAMS: KARPATENT MATH I ID E NSTRASSE 12 TElEX: 5 29 068 KARP O W. 42 Uo / 74 13 / RS P 22 60 778.9-43 Tr.A. Claims 1. fiber cloth, characterized in that it consists mainly of threads, fibers or yarns, from a naphthalate polyester containing at least 85 mole ethylene-2,6-naphthalate units with an intrinsic viscosity of 0.45 to l, o, the fibers, threads or yarns a diffraction intensity ratio (R) between a Bragg reflection angle 2Θ = 18.7 ° and 20 = 15.6 °, is determined according to the X-ray diffraction method, in the range of more than 1.73 up to 5, o have. 2. Fiber cloth according to claim 1, characterized in that the threads, fibers or yarns are not stretched. 3 · fiber cloth, characterized in that it is made by heat treatment of a fiber cloth, which is mainly made of Filaments, fibers or yarns made from a naphthalate polyester with a content of at least 85 mol $ ethylene-2,6-naphthalate units and having an intrinsic viscosity of 0.45 to 1.0, the fibers having a diffraction intensity ratio (R) between a Bragg reflection angle 2Θ = 18.7 ° and 2Θ = 15.6 °, determined according to the X-ray diffraction method, im Range of more than 1.73 and up to 5, ο have at a temperature not lower than 2o5 ° C, but below the Melting point of the cloth under conditions that the following equations 509813/0892 T - 205 * 70e " ² - Tm where T is the heat treatment ^{temperature in 0} C, t is the heat treatment time in seconds and e is the base of the natural logarithm. 4. Use of the üPasertuches according to claim 3 as electrical insulating material. 5. Use of the fiber cloth according to claim 3 as an electrical insulating material according to claim 4, characterized characterized in that the cloth is impregnated with a varnish. 509813/0892 Blank page