DE1735027A1 - Process to improve the quality of polyamide yarns - Google Patents

Description

* - '"-ssen, Kettwige.
lAjBHauptbahnhof · Üdj

Patent registration of the company
Nippon Rayon Co. Ltd.

Ho. 5, Uji-tonouchi
Uji-shi, Kyoto-fu / -Japan-

Process for improving the quality of polyamide yarns.

The invention is concerned with improving the quality of polyamide yarns and in particular with one Process for improving the physical properties of polyamide yarns for industrial use such as the dimensional accuracy, tensile strength and the like., These at the same time are to be produced faster than before and at lower costs.

Polyamide yarns have proven themselves over other fibers in the reinforcement of rubber products for industrial purposes Purposes such as automobile tires, V-belts and tubes

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widely enforced. This is due to the fact that polyamide yarns such as those made of poly-C-capramide, polyhexamethylene-adipamide and the like generally have excellent properties, i.e., for example, are very tensile strength and very kink and tear resistant and have high abrasion resistance own. However, polyamide yarns as a starting material for industrial purposes unfortunately have the disadvantage that they have only poor dimensional stability, i.e. that their Dimensions can fluctuate greatly with changes in voltage, temperature or humidity.

For example, rubber parts that are reinforced with polyamide yarns, their dimensions when vulcanized change at high temperatures.

In order to eliminate these disadvantages, it has already been proposed to stretch polyamide yarns at high temperatures (the so-called Hot stretching) to increase the crystallinity respectively Remove distortions in the polyamide yarns. Polyamide yarns, which are made according to the previously customary hot drawing process treated, but still have some of the distortions present in polyamide yarns, since these cannot be completely removed by these previously common methods. This is because Polyamide yarns, which are stretched relatively quickly, do not treat long enough at high temperatures as it would be necessary to completely remove the distortions in the yarn.

For the cord inserts in motor vehicle tires, for example, it has been proposed that polyamide yarns be used for this purpose to be treated according to the so-called immersion process

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which polyamide threads ir. immersed in an adhesive dip bath which contains resorcinol, formaldehyde and rubber latox, whereupon it is then subjected to a heat treatment be subjected. This procedure vermsr however, inadequately eliminating the distortions in the yarn, because the time periods available for the heat treatment are too short.

Polyamide »· for industrial use such as ^bc. Rriulsweise for in cords for tires, belts and the like have especially low shrinkage value b ^ n ^ seat, which, however bahanilungs- by the conventional Wärm- or dipping is not erziolbar.

The invention is therefore already eir.gar ~ s indicated · -.- object to create an ancestor through which the physical properties of polyamide yarn · ~ -π ^f:;. R industrial "purposes can be improved.

In particular, the dimensional accuracy should be important here. Folyami:! - can be improved for industrial purposes.

To solve iieser gave ", the present invention strike a method, which is characterized, Dai: the polyamide ύθ - 300 min in oir ^ r inorten atmosphere at a temperature between 15Q ⁰ C and at most 10 ⁰ C below its melting point under tension. of C, C5-2,? g / denier is heated.

It is more practical to use the polyamide yarn before heating wound under tension and heated in a closed container. The atmosphere in this closed

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The container should consist of at least 80 volumes of an inert gas, suitably nitrogen, carbon dioxide, argon or hydrogen. Synthetic linear polyamides, in particular poly-C-capramide, poly-hexamethylene adipamide, poly-hexamethylene-sebacamide, poly-11-amino-undecanamide, polylaurinamide, copolymerized polyamide or a mixture thereof are provided for treatment by the method according to the invention. PUER the heat treatment of poly-C-capramide a temperature of between l60 and 200 ⁰ C and for the heat treatment of poly-hexamethylene adipamide a temperature of I60 to 220 ⁰ C as has proven particularly suitable.

The inventive method can be how the examples given below for further explanation clearly show the physical properties such as dimensional stability, strength and the like of polyamide yarns for industrial purposes without reducing other special characteristics of these polyamide yarns.

The practical implementation of the method according to the invention works as follows:

Poly-C-capramide yarns of 840 denier and 140 threads for cord inserts of tires are placed in an autoclave under a tension of 0.6 g / denier and the atmosphere in the autoclave is reduced to an absolute pressure of 100 mm Hg, whereupon nitrogen gas is present therein autoclave is introduced to soften an absolute pressure of 76o JNM Hg. Yarns made from Poly-C- Capramld

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were heat-treated under tension at various temperatures of "170 and 19O ⁰ C 1, 10, 30, 60, 300, 900 and 18,000 seconds. As can be seen from the attached diagram, which shows the relationship between the shrinkage values in boiling water and the heat treatment times represents, the shrinkage values decrease approximately in a straight line during the heat treatment times, while they decrease considerably more if the heat treatment is carried out at higher temperatures.

The shrinkage value of a poly-C-Capramidgarnes in hot air at 135 ⁰ C, which was heat treated at 19O ^U C 900 lake, was 2.5%, while the corresponding value of an untreated yarn was 5.5%.

On the basis of numerous tests it has been found that polyamide yarns for core inserts in tires, for example, have shrinkage values of not more than 5 % in boiling water and not more than h% in dry, hot air when untreated yarns, for which the corresponding values 15 % respectively. 12 %, are treated according to the method according to the invention at about 180 to 190 ° C. for a period of 10 seconds or more than 160 minutes.

According to the invention, polyamide yarns are subjected to a heat treatment in an inert atmosphere for a longer period of time at higher temperatures than in the previously customary processes. Such polyamide yarns are treated at a temperature according to the invention which is not to under I50 C to a temperature 10 ⁰ C below the melting point of the polymers.

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Poly-C-Capramidgarne be heat treated, for example, at a temperature between l60 ° C and 22O ⁰ C and poly-Hexamethyien-Adipamidgarne at a temperature between l60 ° C and 220 ° C.

A treatment temperature below 15O ⁰ C may have an adverse effect on the dimensional stability of the treated yarns, while a treatment temperature which is less than 10 ⁰ C lower than the melting point of the polymer, can destroy it.

According to the invention, the heat treatment of polyamide yarns is carried out carried out under a tension of about 0.05 to 2.0 g / denier, since treatment below 0.05 g / denier is a reduction the physical properties of the treated yarn.

It is known that physical properties such as tensile strength, elongation and denier are markedly deteriorated when polyamide yarns are shrunk at a temperature above 165 ° C. without tension. The strength of the heat-treated yarns can generally be improved by increasing the tension , while it has also been found that the shrinkage values of the heat-treated yarns increase with increasing tension.

However, the period of time required to improve the shrinkage value of a polyamide yarn can be considerably longer when polyamide yarns are treated under tension of more than 2.0 g / denier, which is of practical value; of the method according to the invention would be reduced. For this reason, a tension of 0.1 to 1 * 0 g / denier used.

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According to the invention, it is necessary to replace the atmosphere of the treatment room with an inert gas, such as nitrogen, carbon dioxide, argon or hydrogen, the proportion of which in the container atmosphere should not be less than 80 volume- ^. Polyamide yarns which are treated in hot air of over 170 ^° C. under tension can have a lower tensile strength and discoloration due to oxidation, while polyamide yarns which are treated in the same way in an atmosphere which contains at least 80 % of an inert gas can have such do not have disadvantageous properties.

The duration of treatment to improve the physical. Properties of polyamide yarns in the context of dr-r .invention is between 60 and 300 minutes duration than 300 min does not result in any further improvement in the physical properties such as dimensional accuracy. On the other hand, a treatment time of less than 60 minutes can result in inferior quality of the polyamide yarns treated and most importantly, be uneven.

Admittedly, it is well known that the dimensional stability of polyamide yarns through vine heat treatment is essential to improve, such a heat treatment will, however usually carried out when hot stretching polyamide yarns, because of the higher stretching speed and the larger denier of the yarns only insufficient removal of the distortions or kinks can be achieved.

The inventive method can polyamide yarns at a suitable temperature and in sufficient Distortion removal required lengths

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j treat periods of time in an inert atmosphere, thereby ensuring dimensional accuracy without degradation or reduction the other desirable properties of such yarns is imperative to improve. Appropriately is a polyamide yarn following the hitherto customary hot stretching under the tension already mentioned on one Corresponding winding or the like. Wound and in a closed container introduced, so that a very large amount of polyamide yarns at one time in much shorter Time and can be treated at a much lower cost than before.

The polyamide yarns treated in this way have as the table below shows, much cheaper ones Shrinkage values than those according to the previously customary heat treatment processes treated yarns. Measurements on similar polyamide yarns once (A) after method according to the invention and secondly (B) treated according to 'hitherto customary heat treatment methods J resulted in the following approximate shrinkage values:

(A) 5 % (B) Poly-C-capramide under k% 10 Poly-hexamethylene adipamide under 9

The polyamide yarns treated by the process according to the invention have such excellent shrinkage values that the most varied of industrial parts and intermediate products which are produced from polyamide yarns treated in this way have a significantly higher dimensional accuracy than all such parts which are made from polyamide yarns or under

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Turn of such yarns were produced, which were treated according to the usual methods.

For example, cord inserts for tires made from polyamide yarns that have been treated according to the method according to the invention result not only in the cord inserts themselves, but also in the end products, ie in the finished tires, with a significantly higher dimensional accuracy than previously used polyamide yarns. For example, the ratio of the scatter index of the changes in the dimensions of tires made using polyamide yarns treated according to the invention, the shrinkage value of which was at most 3 % in boiling water, to tires made using untreated yarns is about 1/3 - 1/2.

In addition, polyamide yarns which have been treated according to the process according to the invention generally have a 3 to 5 % higher tensile strength and a 20 to 30 % higher fatigue strength (measured according to ASTM-D885 or the tire fatigue test by Goodyear) compared to the polyamide yarns used hitherto, while their elongation and denier are roughly constant when subjected to the heat treatment process of the invention.

Some exemplary embodiments are intended to explain the invention further below, the shrinkage values in boiling Water were determined in the following way:

A polyamide yarn 50 cm long was used for 15 minutes in immersed in boiling water, after the water was completely removed from the yarn through filter paper, the yarn was

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Leave in an atmosphere with a relative humidity of 65 % at 20 ^° C. for 24 hours. The boiling water shrinkage values were obtained by measuring the reduced length ratio of the tested yarn, while the shrinkage values in dry hot air were determined according to the Japanese industry standard measurement (JIS-L IO17-1963), the length of the tested yarn being 50 cm and the shrinkage value was calculated as a percentage of the shrinkage of the original length of the tested yarn.

Example 1:

Untreated nylon. 6 yarns of 840 denier with 140 threads for tire cord were wound onto bobbins after the usual Koi stretching under a tension of about 0.1 g denier and packed into an autoclave whose atmosphere was kept ^{at 150 ° C. at a pressure of 100 mm Hg} . The atmosphere of the autoclave was replaced by nitrogen gas to about 9a volume and the wound yarns were ^{heat-treated for 120 minutes at ITE 0} C under tension of about 0.1 g / denier, resulting in a G & rn (a). Another yarn (b) was made in the same way, with the exception that the atmosphere of the Amtoklitven consisted of only about ten percent of sticket-off gas.

For comparison purposes, two more games (c) respectively. (d) produced in the same way, where, however, the atmosphere of the 'autoclave ssa 7 © Jt respectively. «U O % awe nitrogen off gas existed. All of these yarns as well as one untreated one

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Gam (c) were tested in the aforementioned manner and gave you the results given in Table 1 below:

(a) 90 Tabel 3.9 1: H (g / Donj 16.3 (b) 80 ) P (Ji) 3.8 9.25 16.2 yarn (c) 70 3.0 k, 0 9.20 16.0 yarn (d) 0 3.0 3.5 8.74 15.9 yarn (e) - 3.3 10.5 8.01 16.2 yarn 2.8 8.8o yarn 13.0

Mean therein

Volume fraction of nitrogen gas Shrinkage value in boiling water Shrinkage value in dry hot air of 180 ° C {%) Tear strength (g / denier) Elongation

K F G

K K

There was practically no noticeable difference in color tones between yarns (a), (b) and (e), while yarns (a) and (b) had higher tensile strength and lower shrinkage values in boiling water as well as in dry hot air than that Yarn (s). The yarn (c) had a lower tensile strength than the yarn (e) and had an unsightly appearance. The yarn (d) was found to be the yarn with the lowest tensile strength and was also stained red-brown.

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173S027

""'' f Im jian R ^ Iocfow

Untreated nylon ^ - yarns of 84o'denier and 'Ϊ40 threads were made in the same' manner 'as'■''ih'iBe ^ sViel'i ^ ibTO ^ aiiaelt / ^ wit' ¹

same '

· ■; - ■■ '. . ■;. ^; ά ire Ui lus π: ^ HjJiITU \ »ζϊν emßalojsni.i aes ^ the exception that four threads on bobbins under a tension of 0.05, Ö / 10, £ 1ind ^1; r, $ g / Üeniiir 'aHif ^ elAAlt'WÜtÖet ^ and each sample of 3 kg for 120 min in an atmosphere

at ΐ80 * ο "ΐ> & ^ βΑ '^

at ΐ80 * οΐ> & ^ βΑ ^

..... _v v <■■■■ '. <- \ \ ncv ;) πΐίΠίΐ '.-. ·; ι - :: ^. ι ^ oi ^ ct ¹ ^ fcoi, RBDoa .nyb'itiw gas contained. Table 2 below shows the results

ilte ftsuttate im Verg ^ ei ^ We! ^ uM ^ a ^ e ^ tfek ^{3 £ Loa}

results achieved in

: C. oiJijdJsT LißiifioiieieqoBn T.-jb aüß rfoi.a yarn (f) and a comparison yarn (g), which under a

Tension of 0.02 g / denier was treated.

Table .2:

Γ. (C; ■■) ^ ; i [Γ ', Γ) ί I. ? L - F (J. (U ^ι !

G Ο, * Ό2

H 0 ⁵ O ^

η η ς

κ ο; γ

M 1.5 10.5 9.1 9.53 13.7. "F. '"' -Vrw 5ΠογθΙ? 3 slb cts.il nerioiess ^ uX Teb anuiüebeei üi.G

Significant in this

: j; oas'igw, A Gib CI SIjSd _t neaaeb otnnßnaL'A him b ^ i; dßT uttering

A Tension when winding

B Shrinkage Value In Boiling Water

C shrinkage value in dryer hotter

at 180 ° C *

xjß I Isxqaiea rai eiw

G-M treats under a spa

0.02; 0.05; 0.1; 0.5 and 1.5 g / ^) enler. ₉ O9887 / 10g | _arU8geoe

BATH ORIGINAL

Cords for tires were produced from these yarns, yarns of 840 denier being twisted with 47 turns over 10 cm to form a single yarn and then two more of these individual yarns each with 47 turns over 10 cm to form raw cords. These raw cords were immersed in an adhesive solution containing resorcinol, formaldehyde and rubber latex, after which they were stretched under heat so that each cord had an elongation of 7 % under a load of 4.5 kg. The properties of these cords are shown in Table J below:

A (g / denier) Table J>: C (Ji) D (kg) E (Ji) - B (Ji) 13.8 14.5 20.4 F. 0.02 io, 5 12.6 12.9 20.6 G 0.05 10.1 io, 7 14.0 21.0 Ii 0.1 6.1 8.5 15.0 20.8 K 0.5 4.9 10.1 15.1 20.9 L. 1.5 5.6 12.4 14.8 20.1 M. 9.7

The meaning of the symbols is the same as in Table 2 with the exception that D is the tensile strength represents.

example 3:

Untreated Mylon 6 yarns were placed on bobbins in the same Wound as in Example 1 and heat-treated under the following conditions, whereupon the in the following

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Table 4 given results. The treatment times were 30, 60 and 120 a. The temperature was 180 ° C., the nitrogen gas content in the autoclave was about 87 % and the tension during winding was 0.1 g denier.

Table 4: It means: Shrinkage value in C (g / denier) D (£) 16.2 A (Ji) B (*) A ^f Shrinkage value in 8.80 16.4 E. 13.0 10.5 B. at 180 ° C 9.05 16.4 P. 9.8 7.5 Tear resistance 9.20 16.2 G 6.2, 5.1 C. strain 9.23 H 3.0 3.9 D. untreated water E. boiling hot air P, drier • from 50V 60 G and H duration of treatment respectively 120 min.

From these yarns , dipped cords for tires were produced in the same way as Ii Example 2 , the following results being obtained:

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..! ■ ι; ^ w ¹ S * «*«

A (Ji) Table 5 * C (Ji) , PM 10.5 Β {%) 14.4 20.4 E. 8.0 13.8 14.7 20.5 P. 5.8 11.6 14.8 20.9 α 4.9 10.4 15.0 20.8 H 8.5

Here, the symbols mean the same values as in Table 4, except that C is the tensile strength represents.

From the above Table 5 it can be seen that the treatment at 180 ° C during eil
Results can be obtained.

treatment at 180 ° C for a period of 120 minutes is the best

Example 4;

Winded yarns were made in the same manner as in the egg game 3 deals with the exception that the temperatures at 160, 170, Ι8β and 190 C and the treatment time Was 120 minutes. The results achieved in this way are shown in Table 6 in comparison with a runttenahdelteh yarn.

A (Ji) Table 6i -r, C (g / Dertier) ¹ DW 13.0 B (* y 8.80 ' 16 ^ 2 ε 9.5 10.5 9.02 16.4 F. 5.7 7.7 9.11 16.5 Q 3.0 4.6 9.23 16.2 H 2.2 3.9 9.31 16.5 I. 3.2

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Herein mean:

Λ, B, C, D, Ji have the same properties as

in Table 4 P, G, H, I treated at 160, 170, 18O

respectively 19O ⁰ C.

These yarns became dipped cords in the same Manufactured as in Example 2, with the in The results given in Table 7 below gave:

A (Ji) Table 7: C (kg) D (Ji) 10.5 B (Ji) 14.5 20.4 E. 9.1 15.8 14.6 20.7 F. 6.1 12.1 14.7 20.7 G VJ 10.2 15.0 20.8 H '4.5 8.5 15.2 20.8 I. 3.0

The meaning of the symbols is the same as in Table 6 with the exception that C is the tensile strength represents.

Example 5:

Untreated nylon 6 yarns of 126Ο denier with 210 threads were treated in the same manner as in Example 2, except that the tension was 0.1 g / denier and the treatment time was 60 and 120 minutes. These yarns were made with

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ORIGIMAL BATHROOM

compared to other yarns which were heated for 30 minutes treated as well as with an untreated yarn. the The results of these comparisons are given in the table below.

A (Si) Table 8: C (g / denier) D (Ji) 12.5 B (Ji) 8.83 16.9 Ξ 9.5 io, 7 9.05. 17.1 P. 5.9 7.7 9.10 17.2 G 2.8 5.0 9.07 17.2 H 3.6 It means:

A-E the same as in Table 4 F, G, H treatment duration of 30, 60 and respectively. 120 min.

^{Cords I 1} Ur tires were then twisted from these yarns, a 1260 denier yarn being twisted with 39 turns over 10 cm and then two such individual yarns twisted with 39 turns over 10 cm to form ron cords.

These Ron cords were immersed in an adhesive solution containing resorcinol, formaldehyde and rubber latex and then stretched under the influence of heat, resulting in a cord with an elongation of 7.0 % under a load of 6.8 kg.

The properties of these cords are given in Table 9 below.

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A (Ji) Tabel 9: Mkg) D (Ji) 10.2 B (Ü) 21.3 21.0 E. 8.3 13.4 21.9 21.2 P. 5.5 11.5 21.8 21.2 G 4.8 10.2 22.0 21.3 II 8.7

The abbreviations have the same meaning as in the Table 8 except that C represents tensile strength.

As shown in Tables 8 and 9 above, in one treatment
would be achievable.

a treatment of 120 min at 180 C the best results

Example 6t

Untreated nylon 6,6 yarns with 1,290 deniers and 210 yarns for tire cords were treated in the same manner as in Example 2, except that the voltage was 0.1 g / denier, and the treatment temperature l60, l80 and 200 ⁰ C. The test results of these yarns result in the same way as in Table 8 from Table 10 below.

A (JO Tabel 10 * D (Ji) 7.4 B (ji) C (g / denier) 17.2 E. 3.8 9.6 8.22 1?, 4 P. 2.4 6.0 8.34 17.4 G 1.9 3.5 8.47 17.7 H 2.9 8.46

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ORIGINAL INSPECTED

Herein mean:

A-E the same as in Table 8 F, ß, H treated at l6o, l8o b> betw. 200 * 'c

Test cords were produced from these yarns in the same manner as in Example 5, with those in the following Test results given in Table 11 gave.

Table 11:

7.7 10.4 20th , 47 j 9, 7th P. 5.1 9.3 21 , 08 -ο, 2 G 3.9 7.0 Il , 40 ■ '- °, 1 H 3.3 6.0 ΐ.Ο , 75 .0, 9

The abbreviations have the same meaning as in the table 10 with the exception that C represents tensile strength.

example ¹ y:

Untreated yarns in the same design as in Example 6 were treated in the same way as in Example 2 , except that the tension was 0.1 g / denier and the treatment time όθ, <jK), ICC and 180 min. The treatment results of these yarns are shown in Table 12 below in comparison with an untreated yarn.

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A (SO Tabel 12: D (Ji) 7.4 B (Ji) C (g / denier) 17.2 2.9 9.6 8.22 17.4 F. 2.5 4.7 8.29 17.5 G 2.4 4.1 8.35 17.4 H 2.0 3.5 8.47 17.6 I. 3.0 8.43

Herein mean:

Λ - E the same as in Table 4 F, G, H, I 3 treatment duration of 60, 90, 120 respectively l80 min.

These yarns were made in the same way as in Example 5 Test cords processed and checked. The test results of these cords are given in Table 13 below.

A (Ji) Tabel 1?: D (ji) 7.1 B (j <) C (kg) 20.5 4.5 10.4 20.47 20.3 F. 4.1 8.8 20.71 20.7 G 3.9 7.6 20.63 20.1 Ii 3.7 7.0 21.40 20.3 I. 5.9 21.25

The abbreviations have the same meaning as in the table 12 except that C represents tensile strength.

Expectations:

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Claims (8)

1. A method for improving the physical properties of polyamide yarns by heat treatment, characterized in that the polyamide yarn 60-300 min in an inert atmosphere at a temperature between 150 C and at most 10 ⁰ C below its melting point under a tension of 0.05-2 , 0 g / denier is heated. 2. The method according to claim 1, characterized in that the polyamide yarn is wound under tension and heated in a closed container. 3. Process according to Claim 1 or 2, characterized in that the heat treatment is carried out in an atmosphere "which consists of at least 80% of an inert gas. 4. The method according to claim 3 * characterized in that that nitrogen, carbon dioxide, argon or hydrogen is used as the inert gas. 5. The method according to any one of the preceding claims, characterized in that the polyamide yarn is made from a synthetic linear polyamide yarn. 6. The method according to claim 5 # characterized in that that the polyamide yarn consists essentially of poly-C-capramide or poly-hexamethylene-adipamide or poly-hexamethylene-sebacamide or poly-11-amino-undecanamide or poly-laurinamide or a copolymerized polyamide or one Mixture of these consists. 909887/1028 7 · method according to any one of the preceding claims, characterized in that a polyamide yarn consisting essentially of poly-C-capramide in one Temperature between about 160 and 200 C is treated. 8. The method according to any one of claims 1-6, characterized in that one consists essentially of Poly-hexamethylene-adipamide made of polyamide yarn is treated at a temperature between about 160 and 220 C. Patent attorney Dr. W. Andreevsky 909887/1028 BAO ORIGINAL