DE2064969A1 - Radial tires. Elimination from: 2055320 - Google Patents

Description

Radial tires

Priorities: November 25, 1969, Japan, ITr. 44-94790 April 50, 1970, Japan, ITr. 45-57554

The invention "relates to radial tires used as cords for the belt or breaker have polyvinyl alcohol fibers twisted under specified conditions, the excellent high temperature properties, such as yarn tenacity, Show yarn initial modulus and yarn creep behavior.

In general, polyvinyl alcohol (PVA) fibers are superior to other synthetic fibers in their breaking strength and in their initial modulus. Their application is therefore new in the area of glass fiber reinforced plastics (PRP) are very widespread. It is a known fact that PVA Pasern, which are stretched to their yield point and shortened by subsequent heat shrinkage, over an excellent Breaking strength and an excellent initial or initial modulus. PVA couples tend to

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mm 2.-

However, similar to other synthetic fibers, their properties "at high temperature are proportional to the increase in temperature greatly deteriorate.

The main aim of the invention is therefore to create radial tires in which new PVA Pasern with excellent Properties can be used at high temperature as a cord for the belt or breaker, which the above do not have the disadvantages of synthetic fibers mentioned .. Invention Radial tires according to this, which these PVA fibers as Cord for the belt or breaker included, therefore, as will be shown later, have excellent Properties in the push rod or plunger test, high-speed test, flexed or Corner test, tread wear resistance test and durability test.

The radial tires according to the invention during their manufacture such polyvinyl alcohol fibers having excellent high temperature properties should be described in more detail below.

Because of the need to adapt to the ever increasing speeds of automobiles in recent years Years will find tires with improved properties, such as High speed behavior, wear properties and Processing ability, very quickly widespread. This is understood to be the so-called radial tires.

The radial tires contain a carcass made of cord, which is arranged parallel to the transverse axis of the tires, and a belt or breaker, which is provided with a belt-like or band-like layer,

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in which a tire cord is essentially parallel to the tire circumference and is arranged on the outside of the carcass to reinforce the tread "or the tread. The Radial tires differ greatly in their structure from conventional cross-ply tires, i.e. into a cord fabric woven cord cut diagonally and at an angle of 40 to 60 against the direction of rotation of the carcass respectively of the substructure is arranged. The most prominent feature of the radial tire is the presence of a belt or ribbon-like layer.

The structure with the above-mentioned features brings many advantages in terms of properties and effects in the radial tire with it, if one for the belt tire cord with properties appropriate to the structure or structure used.

A series of experiments with radial tires was therefore carried out hired, in particular a tire cord for the belt, before finally getting a new radial tire came for the PVA synthetic fibers of the invention be used.

In the radial tire according to the invention, a cord is produced from PVA synthetic fibers which contain 0.2 to 0.9% by weight, based on PVA, boric acid or borate, the yarn tenacity being over 7.2 g / d at 120.degree , the yarn initial modulus is over 100 g / d at 120 ° 0 and the yarn creep is below 2 % , namely at a load of 1 g / d over a period of 60 minutes. The twist constant of the thread (ply) of this PVA yarn in the cord is 800 to 1300. The cable twist (turns / 10 cm) is guided in a ratio of 80 to 100 $> the pade twist (turns / 10 cm).

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The maximum dimensional stability is under the yarn tenacity of the material in a tensile test carried out until it ruptures. It is expressed as that of the Breaking load or force, based on the unit of linear density of the unloaded sample, expressed in Grams per denier «," · '·

The yarn initial modulus is the ratio of tension change, expressed in grams per denier (g / d) to the change in elongation expressed as part of the original length. ■ "

The PVA synthetic fibers used to produce the radial tire according to the invention are highly crystalline and oriented and are characterized by favorable properties at high temperatures and a boric acid (EUBO ₀ ,) or borate content.

Suitable pasers are those in the German patent application P 20 55 320.2 described polyvinyl alcohol fibers. Such PVA fibers can be obtained by using a boric acid or borate containing aqueous solution of PVA (spinning solution) produces, spins them into a predominantly water-based coagulating bath that contains certain amounts of Contains sodium or potassium hydroxide and sodium sulfate, the stretches the threads obtained by means of rollers, neutralizes the alkali adhering to the fibers with acid,

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the fibers are hot-drawn while wet, to adjust to a certain amount of boric acid remaining in the PVA fibers rinses with water, drains, dries and finally dry warm stretched.

As for the preparation of a suitable mixture for the coagulating bath, it should be noted that one for conventional Wet spinning process for the production of boric acid or borate-free PVA fibers used coagulating bath with sodium sulfate is almost saturated if you use sodium sulphate, which serves as a dehydrating salt, for the bath. this one makes because the fibers because of the insufficient Coagulation would stick together tightly when concentrating of this bath would be below 300 g / l. According to the invention For this purpose, certain amounts of sodium or potassium hydroxide are added to the coagulating bath used, whereby the solutions containing boric acid or borate can be spun more easily. In addition, the properties depend of the PVA fibers produced in this way depend only very little on the temperature. Is the sodium sulfate content in the coagulating bath high, it can often be observed that the stretchability of the product is lower. Compared with usual However, boric acid-free PVA fibers, the PVA synthetic fibers produced according to the invention are more stretchable and less temperature dependent.

Various considerations and attempts have therefore been made with regard to the coagulating capacity of aqueous solutions of PVA containing boric acid or borate and the properties of them

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products obtained and found here processes and conditions for the production of PVA synthetic fibers, whose yarn tenacity, yarn initial modulus and yarn creep are hardly dependent on temperature. This new procedure exists in that one spins a boric acid or borate-containing aqueous solution of PVA in a coagulating bath that through Addition of 10 - 100 g / l sodium or potassium hydroxide and 100 - 330 g / l sodium sulphate is strongly alkaline, and the fibers obtained in this way are appropriately aftertreated, such as stretching by means of rollers, their alkali neutralized, they to adjust the amount of boric acid remaining in the fibers to 0.2 to 0.9 wt .- ^, based on PVA, with water rinses, drains, dries and finally dry-stretched.

The boric acid or the borate to the spinning solution is preferably based on PVA, is added in amounts between 1 and 5 wt .- ^. ₁ The spinning solution is kept slightly acidic, especially at pH up to pH_. Inorganic acids such as sulfuric acid, nitric acid or hydrochloric acid, organic acids such as acetic acid, tartaric acid, or mixtures of organic acids and their salts such as citric acid and sodium citrate, acetic acid and sodium acetate, tartaric acid and potassium tartrate, tartaric acid and sodium citrate can be added to the solution as acids .

If the pH of the spinning solution is below 3, it is

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The coagulation speed in the coagulation bath is slower, and the system corrodes due to the excessive acidity. On the other hand, if the pH is above 5> so the solution becomes unstable and more viscous, which creates good spinning conditions or the spinning ability is largely lost.

The concentration of PVA in the spinning solution is preferably 10 to 100 % by weight. The degree of polymerization of PVA should preferably be over 500. As already mentioned, the spinning solution is spun into a strongly alkaline coagulating bath, which mainly contains water as well as sodium or potassium hydroxide in amounts between 10 and 100 g / l and sodium sulfate in amounts between 100 and 330 g / l. A sodium or potassium hydroxide content of less than 10 g / l is unfavorable. For example, it lowers the coagulation speed and the stretchability or drawability during spinning. Quantities above 100 g / l, on the other hand, are also undesirable, since the gelling effect of the alkali becomes so strong that the properties of the fibers, such as yarn tenacity, yarn initial modulus and yarn flow, are more dependent on temperature. If the concentration of sodium sulphate is below 100 g / l, the gelling effect of the alkali covers the dehydrating and coagulating effect of sodium sulphate. This causes the fiber to swell during coagulation, which also has a negative impact on the quality of the product. On the other hand, sodium sulphate concentrations of more than 3J0 g / l deform the fiber cross-section like a cocoon because of the dehydrating and coagulating effect

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surpasses other influences. Pasern with deformed Cross-sections are more difficult to stretch or draw.

The PVA fibers spun according to the invention according to the above process are then subjected to post-treatments. They are stretched, for example, by means of rollers, their alkali is neutralized by means of an acid, they are stretched wet and warm and rinsed with water to adjust the amount of boric acid remaining in the fibers to 0.2 to 0.9% by weight, based on PVA . The boric acid after flushing should it about 0.2 wt .- ^, based on PVA, are because the fibers at levels below 0.2 percent -. $> May otherwise swell during rinsing. When the fibers swell, however, slacks or slacks form in the fibers, which result in uncleanliness when they pass through the rollers, which means that the yarn tenacity, yarn initial modulus and yarn creep deteriorate.

The disadvantages just mentioned do not occur according to the invention, since the amount of boric acid present in the fibers is either react with PVA to form inter- or intramolecular cross-links, are attached to the PVA chains or unreacted can remain. This is one of the essential features of the invention. However, if the amount of boric acid is over 0.9 wt .- ^, the drawability becomes worse, which is associated with a decrease in the absolute values of yarn tenacity and yarn initial modulus.

It can therefore be said that by selecting the optimal coagulating conditions, the process for making a

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Stabilize known Paser with high stretchability leaves.

If, in addition, the conditions for the flushing set so that the remaining residual amount of boric acid from 0.2 to 0.9 percent -. $> Is, we arrive at a product with almost temperature independent properties without the Trockenwarraverstreckharkeit is lowered .

According to the invention, it is necessary to carry out the warm dry drawing of the PVA fibers after rinsing with water, dewatering and drying in order to achieve a total draw ratio of over 150%. If the total draw ratio is less than 1300 %, it is difficult to obtain PVA fibers with the above-mentioned properties. The PVA fibers obtained according to the invention, on the other hand, can have a total draw ratio of 100 %. be stretched.

The thus obtained PVA fibers have the following properties sheep: Garnzähfestigkeit at 120 ⁰ C of more than 7.5 g / d ^#, Garninitialmodul at 120 ⁰ C of more than 100 g / d and Garnkriechen at 135 ° C of less than 2% (at a stretching rate Load of lg / d for 60 minutes). They contain 0.2 to 0.9 wt .- # boric acid. The fibers are superior to conventional boric acid or borate-free PVA fibers in terms of their properties at high temperatures.

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The amount of boric acid remaining in the synthetic fibers is determined as follows:

A PVA-related fiber weighing about 2 g is placed in a crucible and covered with 0.1 molar aqueous sodium hydroxide solution. The mixture is allowed the whole to stand overnight in an oven at 105 ⁰ C, and then heated in an electric furnace 60 minutes to 400 - 50O ⁰ C. The fiber in the crucible is then placed in a beaker, and to add lonenaustausehwasser are added and the everything stand for 6ö minutes. A few drops of phenolphthalein are then added as an indicator and 0.1 molar hydrochloric acid is added until the color changes from red to yellow. The mixture is then heated to boiling for 50 minutes, cooled and neutralized to pH 7 with sodium hydroxide or with hydrochloric acid, after which mannitol is added and neutralized again to pH 7 by titration with 0.1 molar sodium hydroxide solution. The volume (cm) required for titration is determined. The amount of boric acid present in the fiber is calculated according to the following equation, where V / (g) is the weight of PVA in the test product, which was determined according to the method given above, and f and ν (cm) are the strength or the titrated volume of a 0.1 molar aqueous sodium hydroxide solution:

0.62. f. ν
W.

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The belt or breaker means short ge ~ says what the hoop or ribbon is for a barrel. The main qualifications of the material used for the tire cord to make the belt are therefore high toughness as well as high modulus, and the PVA synthetic fibers are for these properties are well known. The usual PVA fibers, however, are still imperfect because of their toughness as well as their modulus drop sharply with increasing temperature, which also applies to other thermoplastic Synthetic fibers apply, for example polyesters or polyamides. The inside of a tire is located moreover while driving

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normally in a state of high temperature, about 10O ⁰ C, there is formed during running and heat builds up, the tiber automatically carries over to the radial tire. since the tire cord for the belt is also affected by this temperature rise. A radial tire made using the conventional PVA fibers, the properties of which are highly dependent on temperature, cannot therefore perform its primary function of being a strong or rigid and non-stretchable belt that monitors the deformation of the tire. Of course, this lack of strength and modulus in conventional PVA fibers can be made up for by increasing the amount of fibers used in a tire. However, this results in the problem * that the durability of the tire is greatly reduced because the build-up of heat or the generation of heat becomes greater depending on the increasing amount of fibers, as a result of which adhesion and fatigue strength decrease.

For this reason, a radial tire is proposed according to the invention, for the production of which the PVA fibers according to the invention with excellent properties at high temperature are used. It was found that the radial tires according to the invention only have the advantages mentioned if the PVA fibers used have a boric acid or borate content between 0.2 and 0.9 wt .- ^, a yarn tenacity of over 7.5 g / d at 12O ⁰ C have d _f have a Garninitialmodul of about ICO g / at 120 ⁰ C and the Garnkriechen less than 2% at 135 ⁰ C.

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These facts apply regardless of the conditions of the construction or the structure of the cord, the heat treatment of the cord or structure of the tire.

One of the factors that must be strictly observed is the construction or structure of the cord, there, in particular the twist number has a strong influence on the properties and quality of the end product. There is none all-inclusive number of twists suitable for any material. It is inseparable from the properties linked to the material. One can therefore choose the appropriate number of twists for the conventional PVA fibers or other fibers are impossible to transfer to the PVA fibers according to the invention. It was therefore a series of real driving tests carried out with tires in which the twist numbers of the PVA fibers used according to the invention are very high were different to find the optimal twist for the cord used to make the belt.

Complicating matters further, the properties of a tire are both directly and inversely proportional to the twist number. The fatigue strength therefore improves in direct proportion, for example, with an increasing twist value, while the module properties such as roll strength, flex or corner strength _{ft are} inversely proportional.

Each type of tire, not only of the radial tire,

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must therefore meet the various qualifications required. The above-mentioned tests therefore showed that the PVA synthetic fibers according to the invention are very limited with regard to their suitable number of twists in order to produce the cord for the belt of the radial tire from them, namely the twist constant of the Tadens (ply) must be 800-1300 and the Kaßel twist (Windurigen / 10 cm) at 80-100 % of the thread twist (turns / 10 cm). The term used according to the invention "twisting con-

staute "is represented by the letter K in the following Equation given, where D stands for denier and T the Number of twists (number / 10 cm) is:

K = Vl). T

The. The number of twists increases as the value of K increases. _:

If the twist constant of the thread is below 800, not only does the shape of the cord become very irregular and thus the quality and appearance of the tire deteriorate, but also the fatigue strength of the cord becomes insufficient, so that the cord breaks earlier than the tread or tread wear, which shortens the life of the tire. The number or the value of the Cable twisting (turns / 10 era) has a larger one Influence on the fatigue strength as the thread twist (turns / 10 cm). The durability of the tire is also

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worse if the cable twist (turns / 10 cm) is less than 80 % of the thread twist (turns / 10 cm).

On the other hand, if the twist constant of the thread is greater than 1,500, properties of the PVA fibers, such as high toughness and high modulus, are lost, which means that the advantages of radial tires in terms of rolling resistance, tread or tread strength and YJaIk or corner strength are lost. The Karel twist (turns / 10 cm) should also not go beyond the limit given above, i.e. not more than 100 $ of the thread twist (turns / 10 cm), since this not only reduces the tenacity and the modulus of the cord considerably, but also kinking of the cord under relaxation as well as processing and other difficulties arise.

The tire cord is usually subjected to a dip treatment, to give it such an adhesion to rubber. The adhesive used according to the invention is not limited to certain types, but any adhesive used in the rubber industry can be used is common. RFL, a mixture of an alkaline initial condensate made of resorcinol and formalin with latex, is particularly preferred, or one that instead of latex is polyvinylpyrrolidine contains. The conditions of the immersion treatment may be the same as those of treatment methods for cord

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conventional cross-ply tires can be used. The drying, curing in the heat drawing and heat treatment are carried out at temperatures above 200 ^0C.

To carry out the invention, for the carcass or any material can be used for the substructure, too is used to produce the usual bias tires.

The invention can also be used for the production of diagonal tires provided with a belt or a band, which have a belt-like or band-like layer of tire cord which runs essentially parallel to the tire circumference and outside the carcass to reinforce the tread or tire. of the profile is arranged as

this is the case with radial tires, the carcass however, it has the same structure as the normal cross-ply tire.

Before the invention is explained in more detail using the examples The various methods of investigation that were used to determine the properties of radial tires will now be described.

A. Flung test '

The result is determined from the occluded energy (kg:. em) before the tire by longitudinal penetration of the plunger breaks. The internal pressure of the tire is 1.7 kg / cm. The higher the value, the more solid or

The tire is stronger *

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B. HIGH SPEED TEST

According to MVSS No. 109 (ASTM), ^{tires adjusted to a pressure of 1.7 kg / cm 2 are left} at 80 km / h. start on a test drum. If there is no damage to the tires after a predetermined running time, the speed is increased in stages. The result is determined by the maximum speed (km / h) when the tire breaks and the running time (minutes) at the same speed. The larger this numerical value, the greater the high-speed strength.

C. Flexibility or corner strength

The walk or. Corner force (kg) of a tire adjusted to a pressure of 1 * 7 kg / cm becomes at a speed of 30 km / h, a load of 125 kg and measured at a grinding angle of 10 °. The one obtained by dividing the flexing or corner force by the grinding angle The value gives the flexing or corner strength (kg / degree). The larger this value, the better the fulled or Corner properties. .

D. Abrasion resistance of the tread or profile

You leave an automobile with its tires on a pressure

of 1.7 kg / cm are set, drive on a test track,

After a distance of 20,000 km at a speed

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speed of around 80 to 100 km / h. is the abrasion of the Tread or profile that touch the ground, measured. The abrasion resistance of the tread respectively of the tread is expressed by the distance that the tire covers up to 1 mm of it is. The greater this value, the greater the abrasion resistance of the tread or profile.

E. Durability

A car whose tires are adjusted to an air pressure of 1.7 kg / cm is left on a test course for 20,000 km at a speed of about 80 to 100 km / h. to run. The strength of the cord is determined by examining the tire cord of the belt or breaker before and after the test run. It is expressed in residual strength (%) of the cord of the tested tire versus the original cord. The higher the value, the greater the durability.

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Example 1:

1.7 kg of PVA with a degree of polymerization of 1750 and a saponification number of 99.5 mol- # as well as 34 g of boric acid and a small amount of nitric acid required to adjust the pH to 4.3 are mixed to 10 kg of aqueous PVA solution . This spinning solution is spun through spinnerets with 600 spinning holes 0.08 mm in diameter into a coagulating bath which contains 350 g / l sodium hydroxide and 230 g / l sodium sulfate. The fibers spun in this way are then pulled out of the bath at a speed of 10 m / min, and then subjected to post-treatments, such as whale stretching by 100 #, neutralization in a bath with 70 g / l sulfuric acid and 500 g / l sodium sulfate, hot wet stretching by 150 % _s rinsing with water / water to adjust the boric acid content to 0.45 #, dehydration and drying and finally hot dry stretching to 220 %. The end product thus obtained is stretched to a total stretching ratio of 1500%.

The product then has a Garnzähfestigkeit of 9.3 g / d at 120 ⁰ C, a Garninitialmodul of 135 g / d at 120 ⁰ C and a Garnkriechen 1.4 # at 135 ° C.

PVA fibers according to the invention are used to produce radial tires for passenger cars with the size 165-13 niit 1200 d / 600 f (f is the number of threads) used for the belt or breaker, while high-tenacity rayon Super-2 with

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1650 d / 1100 f is used for the carcass. Both yarns are twisted and processed into cord fabric with the characteristics given in Table 1.

Table 1

Classification material A 1200 d / l / 3 Material B construction 1650 d / 1/2 Twisting resp. Twist number: 30th Thread (ply) (turns / 10cm) 25th 50 Cable ( " " ) 50 Cord twist con 1039 stante of the thread 2031 Cable twisting or twist / Thread twisting or twist 83 χ 100 {%) 100 Twist direction: Thread twisting or PIy- Z twist S. Z . Cable twisting 32 S. Cord density (ends / 5 cm) 49 tissue

Both cord fabrics A and B are in the usual way RFL solution submerged. The cord fabric A is then 3 minutes

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wafmbehandelt dry at 200 ⁰ C, whereby the cord is stretched by 2.5 £. The cord fabric B is dried at 150 ⁰ C, however, and its original length.

Using the above-mentioned cord fabrics to form the belt or breaker and the carcass one arrives at by conventional methods such as rubber dipping, tire molding, vulcanization and post-curing for the invention Tires »However, the present tire was made up of 4 layers or plys in the belt or breaker and 2 layers or plys in the carcass »

The results of various tests on the properties of the tires are shown in Table 2. Radial tires were used as comparison samples, their structure and Big resembled the tire according to the invention, but for that PVA fibers are used to manufacture the belt or breaker which did not satisfy all of the manufacturing conditions and characteristics of the invention. The results of the investigation of the comparative examples are also given in the table.

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Table 2

Material:
Degree of polymerisation des
PVA example
1 1 1750 2 "" 3 7 comparative examples
■ 4. 5 "β. 1000 I75O I75O '' T Saponification number of PVA
(MoI-Jg) 1750 99.5 1750 1750 1750 99.5 99 * 5 1750 - * Spinning solution:
^ Concentration of PVA {%) 99.5 17th 99.5 99.5 99.5 18th 18th 99.5 nong ⁰⁰ amount of boron added
»Acid {%) 17th 2.2 17 17 17th '2.6 2.6 17th ingui ^ pH 2.0 4.1 2.2 2.2 2.2 .4, O ³ 2.0 • σ
(L)
Xi »Ι coagulating bath
»NaOH (g / 1) 4.3 8th 4.1 .4.1 4.1 40 40 • 4, * 3 ² .ungs Na ₂ SO ₄ " 50 260 110 80 15th 220 220 50 r—)
O Neutralizing bath:
H ₂ SO ₄ (g / 1)
Na ₂ SO ₄ 230 70
300 150 90 5βο 80
52Ο 80
520 230 Manuf Stretching:
Total draw ratio (%) 70
300 1100 70 not 70
spinnable
300 300 I5OO 1200 70
300 Roll stretching ($>) 1500 bad
rolling
stretchable 1200 bad 100
roller
stretched
bar 100 1100 100 bad
crazy
able to 100 ·;

Continuation table

C. Q) faO • Η C

example 1 Comparative examples 4 " 5 6th - 7th 1 2 5 150 140 I50 Wet drawing in the
Heat {%) 150 220 192 140 Dry stretching
in the warmth ($) 220 0.51 0.49 0.15 1.00 0.46 Amount of residual boric acid 0.45 6.2 0.52 5.4 7.5 7.0 6.5 Tenacity
(120 ⁰ C) (g / d) 9.5 72 7.0 65 91 82 96 Initial module (120 ⁰ C-) (g / d) 155 2.5 82 5.1 2.5 2.4 2.5 Creep (155 ⁰ C) (#) 1.4 5524 2.2 2645 4652 4298 5485 Plunger test (kg.cm) 5865 184.10 4175 16Ο, 4Ο 208.25 184.24 192.20 High speed test
[(km / h), min.] 217.20 51.9 192.25 50.2 50.7 52.5 55.4 Flexibility or edge strength
(kg / degree) 40.5 7710 52.8 7650 8050 7960 8140 Tread or profile
strength (kg / mm) 8920 75 8290 70. · 86 82 89 Durability (%)
\
1 95 76

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Continuation of table 2 Comments:

* 1 means that the pH with tartaric acid was discontinued

* 2 means that the pH value has been adjusted with acetic acid and sodium acetate.

In Example 1 to Comparative Examples, nitric acid was used to adjust the pH used.

Example 2:.

PVA fibers containing sodium borate are produced according to the procedure described in Example 1, but 1.5 % sodium borate, based on PVA, is used instead of boric acid, and tartaric acid is used instead of nitric acid to adjust the pH. The fibers are drawn to a total draw ratio of 150 #. The product obtained has a Garnzähfestigkeit of 9.1 g / d at 120 ⁰ C, a Garninitialmodul of 127 g / d at 120 ⁰ C and a Garnkriechen 1.5 # at 135 ° C.

In the manufacture of radial tires using the above yarn, the properties of tires become mutually exclusive compared, in which the twisting of the cord for the belt or breaker was changed as indicated in Table 3:

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Table 3

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Example Comparative Examples 2 8 9 10 11

Twist number:

Thread (ply)
(Turns / 10 cm) 30th 30th 23 18th ho ' Cable (turns /
10 centimeters) J® 20th 11.5 18th 40 Twisting resp.
Twist direction: thread Z Z Z Z Z cable S. S. S. S. S. Twisting or.
Twist constant of. ...
Thread 1039 1039 .797 - 624 1386 Cable twisting or
-twist / thread thread- twisting
. 100 {%) . 100 67 50 100 100

no mand the cord ditto ditto no defects "gel after in that after one;

a run belt run of!

from 40000 broke to "
km a run

from 30000 24000 12000

km km km

40,000 km

Durability {% of the remaining strength of the cord after a run of 20,000 km)

Flex or edge strength (kg / degree)

97

40.3

81

73

39.6 43.3 45.6

96

30.6

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Example 3;

An aqueous solution of PVA in a concentration of 15 wt .- #, which contains 150 g of PVA with a degree of polymerisation of 2350 and a saponification number of 99 * 5
Mol- #, is mixed with 30 g of boric acid (2 wt. - $>, based on PVA) and a small amount of acetic acid, so as to
to reach a spinning solution of pH 4.5. The spinning solution is spun into a strongly alkaline coagulating bath, which essentially consists of water containing 40 g / l
Contains sodium hydroxide and 250 g / l sodium sulphate. the
Pasern v / earth at a speed of 10 m / min, pulled out of the bath, stretched to 100% by means of rollers, neutralized, wet hot stretched to 150 %, to adjust the boric acid content to 0.4 wt .- ^, based on PVA, Rinsed with water / water, drained and dried and finally stretched dry to $ 200> dry. The product obtained
(1200 d / 600 f) is then brought to a total draw ratio of 1400 % . The product obtained here has a
Garnzähfestigkeit of 9.2 g / d at 120 ° C, a Garninitialmodul vonl31 g / d at 120 ⁰ C and a Garnkriechen of 1.9% at 135 ° C · It has excellent high temperature properties.

The yarn produced by the above process is used to make the belt or breaker of radial tires by dividing it from those mentioned below
Conditions twisted into a cord (1200 d / l / yy):

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Thread twisting or twisting Cable twisting or twisting

Cable twisting / thread twisting. 100

50 turns / 10 cm 50 turns / 10 era

Direction of Twisting Z of the twist: S. Thread (ply) Cable. 1039 Twisting or twist constant des Thread

100

No errors were observed after running 55,000 km. The fatigue strength was 98 % and the flexing or corner strength was 40.8 kg / degree.

Example 4 :

An aqueous solution with 17 wt .- ^ PVA, the 100 kg PVA with a degree of polymerisation of 1750 and a saponification number of 99.9 mol # is used for production a spinning solution with 2 kg of boric acid (2 wt .- ^, based on PVA) and 0.3 kg of acetic acid (0.005 equivalent, based on 100 g of PVA). The pH is kept at 4.5.

The spinning solution is through nozzles with 1000 holes and

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0.15 mm diameter spun into a coagulating bath containing 50 g / l sodium hydroxide and 200 g / l sodium sulfate. The pasers are at a speed of 10 m / min. pulled out of the bathroom. The spinning behavior is very stable in this case * During the two-week spinning no problems arise, such as clogging of the nozzles, etc. The fibers obtained are then processed further in the same way as in Example 3. They are stretched on rollers, neutralized, wet-heat-stretched, with water rinsed to adjust the amount of boric acid to 0.5% by weight , based on PVA, dehydrated, dried and heat-stretched dry. The product obtained in this way (1800 d / 1000 f) is brought to a total stretching ratio of 1200 % . It has a Garnzähfestigkeit of 9.3 g / d at 120 ⁰ C, a Garninitialmodul of 13 ^ - g / d at 120 ⁰ C and a Garnkriechen of 1.8% in

The yarn obtained in this way is used to manufacture the belt or breaker of a radial tire by placing it under de, n in the following conditions twisted into a cord 6,8OO d / 1/2):

Thread twisting 30 turns / 10 cm

Cable twisting 30 turns / 10 cm

Twist direction:

Thread Z

Cable S

Twist constant of the thread 1272

Cable twisting / thread twisting

twisting. 100 {%) loo

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No errors were found after running 35,000 km. The fatigue strength is 96 % and the flexing or corner strength is 41.2 kg / degree.

10 9 8 8 3/1563

Claims (2)

1.! Radial tire, the belt or breaker of which is made of cord, - ^ characterized in that the cord is polyvinyl alcohol fibers with a yarn tenacity of over 7.5 g / d at 120 ° C, a yarn initial module of over 100 g / d at 120 ° C, a yarn creep of less than 2 % at 135 ° C and a boric acid or borate content of 0.2 to 0.9 wt .- ^, based on polyvinyl alcohol, the twist constant for the thread (ply) 800 1300 and the twist for the cable (turns / 10 cm) is 80 - 100 % of the thread twist (turns / 10 cm). 2. Radial tires after. Claim 1, characterized in that a spinning solution of polyvinyl alcohol containing boric acid or borate at a pH between 3 and 5 is spun into an aqueous solution containing 10-100 g / l alkali hydroxide and 100-330 g / l sodium sulfate for the production of the polyvinyl alcohol fibers contained contains, the filaments obtained are stretched by means of rollers, neutralized, hot-drawn while wet, the amount of boric acid or borate is adjusted to 0.2 to 0.9 wt up to a total draw ratio of over 1300 %. 109883/1663 · / . / ORIGINAL! IMSPEGTH)