JPS5953736A - Polyester tire cord and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester tire cord, particularly a polyester tire cord having high modulus and improved dimensional stability and fatigue resistance, and a method for manufacturing the same.

In recent years, there has been a demand for tire needs suitable for radial tires that have excellent handling stability and ride comfort when running at high speeds. An improved method for producing polyester fibers suitable for the high-performance tires has been proposed. For example, there is a method disclosed in Japanese Unexamined Patent Publication No. 55-58032. The polyester fibers obtained by this method exhibit the above-mentioned performance and are considerably improved when compared with fibers obtained by conventional methods. But this way? When trying to obtain a constant modulus and strength of a tire cord made of polyester fibers thus obtained, the elongation at break decreases and the amount of work during elongation decreases. If such a tire cord is used as a carcass material, the tire cord will not easily break due to the low load charge absorption energy. Therefore, in order to be safe even when applied to large tires, we have developed a polyester plastic tire cord (hereinafter referred to as tire cord) that has a large amount of work during elongation (hereinafter referred to as toughness) and has a large energy absorption capacity. As a result of intensive research into a method for manufacturing tire cords having the above-mentioned useful performance, the present invention was arrived at.

That is, the present invention proposes a high-strength tire cord with high modulus and improved dimensional stability and fatigue resistance, and also a tire cord with greatly improved toughness, and a method for manufacturing the same. i-Toughness refers to the amount of work (Jutsuno, J) determined by drawing a load-elongation rate curve while stretching the tire cord and measuring the area surrounded by the load-elongation rate curve and the elongation skewer axis. .

The above objectives are iJ, TV (intrinsic viscosity) of 08 or more, and birefringence (△n) of 2.
Polyester undrawn yarn with a size of 5 x 111' or more and a density (ρ) of 1.538 or more is 95% of its limit stretching ratio.
To obtain a drawn yarn having the following properties by stretching it at a draw ratio of less than 1.5%, and then subjecting it to relaxation treatment of less than 1.5% or tension treatment of less than 5.0%, and then winding it up. (Il T/I' ) ≧ 7.5 g/d
-) 18≧DK≧16% (c) 150≧Mi≧90 g/d) 15≧Mtg/d W) Twist the above drawn yarn with a twist coefficient of 2000 to 2500 to make a raw cord, Bi) 230 to 260℃ after applying adhesive to the three raw cords above
This is achieved by subjecting the cord to a tension heat treatment for 60 to 240 seconds while applying 1 to 8% stretchin to produce a treated cord having properties of 4.0≧MDE≧30%.

This method yields a polyester tire cord consisting essentially of polyethylene terephthalate fibers, which simultaneously satisfies the following properties.

(a) 452MJ'1E230% (b) 2 5 ≧ M t '4 5
g/a ＼) 35≧W≧2.4J Salary) 8220% to 502 This tire cord uses conventional tire need and MDI @
When a high modulus code is created by setting the recording range e, there is a significant difference particularly with respect to Mt and W.

More specifically, the method of the present invention and the characteristics of the tire cord obtained by the method will be described in detail below. 1st
The figure is a process diagram to which a major embodiment of the method of the present invention is applied.

The tire cord of the present invention is substantially made of polyethylene terephthalate fibers, and is made of polyester JV in which 90 mol% or more of all repeating units in the polymer molecular chain are polyethylene terephthalate units. Such polyesters include terephthalic acid and hyethylene glycol, ethylene oxide components, aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, and diol components such as propylene glycol-JV and butylene glycol. There are copolymerized polymers in which the latter component is copolymerized, or mixed polymers in which a polymer obtained from the former component and the latter component is melt-mixed with polyethylene terephthalate.

The engineering value of polyester fiber is 08 or higher, usually 08 to 1.
2 is preferred. In order to obtain a polyester fiber having the above-mentioned process V after spinning and drawing in the process of the present invention, the process (I) of the polyester (V) polymer to be subjected to melt spinning is 085 to 1.
40 is used. In addition, the value measured by the following method is referred to as the value.

using an Ostwald viscometer. -chlorophenol-w(
The relative viscosity η of a solution in which 2 g of a sample was dissolved in 5 ml of OCP)2 was measured at 25° C. and calculated using the following formula.

Engineering V: o. 0 2 4 2η, + 0. 2
6 3 4ηr=(txa)/(tOXdo)
However, t and 'fio are the sample solution and ocp, respectively.
The falling time, d and do are the sample solution and ocp, respectively.
The density at 25°C.

The undrawn polyester yarn of the present invention having Δn of 2 5 X 1 Q"'-' or more and ρ of 1338 or more can be obtained by the following method.

(1) Melt the polyester polymer and spinneret 0
(2) Directly below the spinneret, 5 to 100 (7), usually 5 to 50
Attach the α heating cylinder (6) and heat the melting point of the polymer to 40
After passing the nff spun yarn through the heating cylinder atmosphere 03 heated to below 0°C, a cold air θ of 10 to 50°C is immediately applied.
(3) After applying an oil agent to the cooled and solidified yarn, the yarn is sprayed at a rate of 1500 m/min or more, usually 1500 to 600 m/min.
It is obtained by taking off the yarn with a take-off roll rotating at a surface speed of 0 00 m/min and taking it off with a pick-up roller. Installing a heating cylinder directly under the nozzle and passing the spun yarn through the atmosphere inside the heating cylinder is remarkable for improving the uniformity of the relatively highly oriented undrawn yarn of the present invention and increasing the drawability. It has a great effect.

The above Δn and ρ are values measured by the following method.

Using a polarizing microscope XTP-11 manufactured by Δnconi Co., Ltd., the measurement was carried out using a sodium lamp D line at 1/1 ratio with the light source and the usual Benz convencator method.

ρ: Measured at 25° C. using a density gradient tube prepared using bromine tetrachloride as a heavy liquid and n-hebutane as a light liquid.

A comparatively highly oriented, high density undrawn polyester yarn obtained by the method described in AiJ was rolled at a drawing speed (IFR: 1
After being taken off in step 8), the material may be wound up on a bobbin and then stretched, or it may be stretched continuously without being wound up. FIG. 1 shows a direct spinning drawing method as an example of a suitable drawing method.

The take-up roll (iFR; 18) is heated to 100° C. or less, or used without heating. Yarn feeding roll (2
FR: 19) is heated from the glass transition temperature of polyester to 150°C, preferably from 80 to 100°C. 0~ No substantial stretching occurs between IFB and 2FB
Apply 5% surucci.

This has the effect of stably supplying the drawn yarn to the subsequent drawing process, but 2FB may be omitted. 2] J and
The first stage of stretching is performed between a first stretching roll (iDR, 20) heated to 80 to 150°C, preferably 80 to 120°C. If 2FR is omitted, iFB and IDR
The first stage of stretching is performed between. The stretching ratio is 1.20-2.
0 0 , preferably 1.60 to 170. Then IDR and 2DR (
21) between 110 and 160, preferably between 1.20 and 1
, 2-stage stretching at 50 times. After the second stage of stretching, a relaxation of less than 1.5% or 5 Apply a tension of less than % and then wind it up with a winding machine. The total stretch ratio (IFR/2DR) is 1
．． Select from the range of 1 to 5.0 times, but the limit stretching ratio is 9.
Do this at less than 5%. The limit stretching ratio is the maximum stretching ratio at which stretching can be performed for 2 minutes or more without yarn breakage.

The selection of the polymer IV, the spinning conditions and the drawing conditions must be determined in relation to each other to produce a drawn yarn having the following properties.

(I T/D C 7.5g/d(B)
1 8-≧ DE213 %tz)li, 50≧
M 1190 g/d H) 15 Mtg/d Note: 1) The definitions and measurement methods of the characteristics are as follows.

(+J T/D, nw, MIBJ engineering 8-L10'17
It was done using the method. The load-elongation rate curve was measured under the following conditions. 20°C, 65% RH & controlled atmosphere
After being left for 24 hours or more, measurement was performed using a 1 Tensilon UTM-4L tensile tester (manufactured by Toyo Baldwin Co., Ltd.) at a test length of 25 cm and a tensile rate of 60 α/min.

From the load-elongation rate curve obtained here, T/D, DE, M
'i was determined according to the definition of JIS-Li017.

) On M, in the same load-elongation curve as mentioned above, on the curve obtained by subtracting 24% from the cutting elongation (this is the solder obtained by multiplying the stress increment by 2.4 x j D '). .

The tire cord of the present invention is disclosed in Japanese Unexamined Patent Publication No. 56-580'
No. 32 (Thus, the toughness is significantly improved compared to the tire cord made of W fibers, but the Bolier stell fiber used as the tire cord yarn has the following characteristics in particular.

(1) The individual filaments of the fiber are uniform, and the strength/elongation product is easy. (2) The DK is relatively low, and the Ml is relatively good. These characteristics are (1) The spun yarn is (2) Stretching at a stretching ratio of less than 95% of the limit stretching ratio; (3) Relaxation treatment of less than 15% or less than 5% after stretching. It is expressed by processing the tension of.

Polyester fibers with the above characteristics have a twist coefficient of 2000~
The yarn is twisted at 2,500 yen to make a raw cord. The main application in which the performance of the tire cord of the present invention can be effectively utilized is as a carcass material for radial tires, and the above-mentioned twist coefficient is determined.

Next, the raw cord is woven as it is or into a sag, and then dipped in a common tire cord adhesive, such as RFL (resorcinol-formalin-latex mixture).The adhesion rate of the adhesive is 1 to 6%, usually 2 to 5%.Next, after drying the adhesive by passing it through a heating oven, it is subjected to tension heat treatment, but these are usually carried out continuously.Since the tire neat of the present invention is designed to have a high moshulasun structure, M DE is set to 30 to 4.0% e.Tension heat treatment is performed at a temperature of 260 to 260°C, preferably 240 to 255°C, for 50 to 300 seconds, preferably 60 to 200 seconds, and the tension rate is 1 to 8%. , preferably 2
This is achieved by processing at ~6%. The tire cord of the present invention, even as a high modulus cord through the above-described treatment, maintains superior dimensional stability than conventional tire cords with low modulus. Tension room 34p is usually 2
A method is adopted in which the tension is applied in the hot zone in the first stage, and the normal tension in the second stage is low or relaxed in the V zone, but the result is that the total tension rate is within the above range. .

The tire cord thus obtained has the following characteristics.

(a) 4.0 ≧ +xnb-=x, o % (b)
2 s2+xt ≧ 5 g/d (c) 3.
5 2 W ≧ 2.4 J (=) 5. Oa
Hes, 4 2. 0% The definitions and measurement methods of the properties (a) to (a) above are as follows.

(a) MICE: T/D of the yarn, ]'lE, Mj,
A tensile test was carried out on the tire cord in the same manner as above, and the load -
Obtain the elongation rate curve. In the load-elongation rate curve, when the fineness of the raw yarn is D and the number of twisted yarns is n, the elongation at the time of +000x2 load is determined and this is defined as MDE.

MJIE is a parameter that indicates the modulus of the tire cord, and the smaller the MDE, the better the modulus.

(b) Mt: Same as Mt of yarn in iiJ. However, the fineness was determined without correcting the weight of the adhesive attached to the tire cord E.

(c) In the load-elongation rate curve of W, (a), a perpendicular line is drawn from the cutting point to the elongation rate lll1lIL parallel to the load axis, and the area surrounded by the load-elongation rate curve and the elongation rate axis. I calculated the work nails and converted them.

) △S: Take a quill cord sample in a shape and heat it at 20°C.
After leaving the sample in a conditioning chamber at 65% RH for more than 24 hours, the sample with the measured length eO was placed in an oven at 177°C under no tension for 30 minutes with a load equivalent to 0.1 g/dt of the sample. After leaving it for 1 minute, it was taken out of the oven, left in the control chamber for 4 hours, and then the above load was applied again and the measured length was 1. It was calculated from the following formula t.

ΔS=(#o jh )/jio Xl 00% The tire cord of the present invention has a low MDE, that is, a low modulus, but a low Mt and a relatively high DE. As a result, a characteristic load-extension curve with a large tW is obtained as shown in FIG. On the other hand, the tire cord obtained by the method described in iii.
\, so MDE can be designed low, but in this case, Mt is high <
, I) E is also low, resulting in curve B with small W. In addition, conventional commercially available tire cords have poor dimensional stability, so
Normally, low MDEf is not designed. The result is a curve like C. If dimensional stability is ignored and the MDE is processed to be equivalent to the tire cord of the present invention, the result will be curve C', which will result in higher strength but higher Mt, lower DE, and, as a result, lower W.

When the tire cord of the present invention having the above-mentioned characteristics is used as a car cane material for a radial tire, it becomes a high-performance tire with excellent dimensional stability, excellent handling stability and ride comfort during high-speed running.

In particular, due to its high toughness, it exhibits even higher performance when used in large tires that undergo large deformations under high loads during driving. On the other hand, by taking advantage of the above-mentioned characteristics, 2 is also useful as a rubber reinforcing cord for applications other than tire cords, such as (2) belts, timing belts, conveyor belts, etc.

The present invention will be explained in detail from Example t below.

Example engineering v 1.28, carboxyl end group concentration 185 (e
q/10 g g) of polyethylene terephthalate chips was spun using a radar-type spinning machine.

The polymer temperature is 295°C, and the cap has a hole diameter of 0 and 6.
m, the number of holes is 288. Also, the discharge amount is 530 g
/ minute. (Table 1 sample 540 conditions) There are 10
Attach the heating cylinder (7) and set the atmospheric temperature inside the heating cylinder to 50.
The temperature was 0°C. The yarn spun from the spinneret passes through the atmosphere inside the heating cylinder, is rapidly cooled and solidified with cold air, and then passes through the oil supply row I.
After being coated with oil, it was taken over by a Nelson Rono V rotating at a surface speed of 2,000 m/min. △ of the drawn thread
n was 55'110'', and ρ was t642.The drawn yarn was drawn and wound continuously using the apparatus shown in Fig. 1 without being wound up once.The drawing ratio and relaxation rate after drawing were changed. When the yarn was wound, yarns with different properties as shown in Table 1 were obtained.The discharge amount was slightly changed in accordance with the changes in the stretching ratio and relaxation rate, and the yarn was adjusted to approximately +000 denier. .Each temperature of the roll is IFR: 80℃, 2F
R: 90°C, IDR: 110°C, 2DR: 245°C,
RR° was not heated, and the number of yarn turns (T) on the roll was 4T, 5T, 5T, and 7T, respectively.

It was set to 4T. Moreover, the limit stretching ratio at this time was 2.49 times.

Next, both the first twist and the first twist of the Hokugi Ikkyo yarn were twisted with 49T/10 flaws (twisting coefficient of about 2500), and the two yarns were twisted together and made into a raw cord. The raw cord is made by Riller Co. (USA), and is made of resorcinol formalin latex and IC1 Co. (UK) "fJJ II p K X I".
It was passed through an adhesive solution containing JL II as a main component. The amount of adhesive purchased was set at 20%, but the amount of adhesive (=1 piece was approximately 6%)
It was adjusted so that 160℃ to dry the adhesive
The process was carried out for 60 seconds at a constant length in a heating furnace at
After treatment for 0 seconds, 250° without giving 1% relaxation.
It was heat-treated for 70 seconds at C ()) V Marzone) to obtain a tire cord.

The characteristics of the obtained tire cord are shown in Table 2. It can be seen that the tire cord of the present invention has specific yarn characteristics and can be obtained only when the cord heat treatment conditions after applying the adhesive are specified.

Comparative Example: When a commercially available polyester tire cord fiber was obtained, T/D = 9.3g/li, DE -132%
, Mi=115g/σ, Mt-24.2g, /6. Also, Example n of JP-A No. 53-58032
When raw yarn was produced according to 1, T/D = 8.0
g/σ, DE=10.2%, M j, =102g/d
, Mt=53.0 g/d yarn was obtained. Each of these fibers was twisted and twisted in the same manner as in Example 1, applied with an adhesive, and heat treated to obtain a tire cord. Although the heat treatment was performed by changing the tension ratio, the tire cord characteristics of the present invention could not be obtained as shown in Table 5.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing one embodiment of the present invention. FIG. 2 shows a load-elongation curve diagram of the tire cord according to the present invention. 10. Spin block 11: Base 12 Heating cylinder 13, Atmosphere inside the heating cylinder 14 Cooling cylinder 15 Cold air 164 Chimney duct 1 17: Oiling roll 18 : Taking-off roll IFR) 19 Supply roll (2FR) 20: First stretching roll IIIR) 21 Second stretching roll IIDR) 22: Tension adjustment roll (RR) 23: Winding machine Y: Itojo book k fraud out work person air 1
ノ I/I: +A Platform construction diagram 1
Figure 2 Procedures Amendment Heart 1, Case Indication Showa 5741 "Patent Application No. 164045 2, Title of Invention Polyester Tire Cord and Method of Manufacturing 6 Person Who Makes Amendment, f+., Patent Applicant Shi-38 29220 (Stuttering 9-5) Number of inventions increased by amendment. Procedural amendment 1. Indication of case Annex I” 1957 Patent Application No. 164045 2, title of invention Polyester tire cord and its manufacturing method 3 Amendment Relationship with the case involving the person who filed the patent application Address of the patent applicant: 2-2 Nihonbashi Muromachi, Chuo-ku, Tokyo
Issue 5 Number of inventions increased by amendment 0 6 Subject of amendment; ze 1, 4.゛, two

Claims (2)

[Claims] (1) A polyester tire cord which is actually made of polyethylene terephthalate fibers and is characterized by simultaneously satisfying the following properties. (a) 4.02+4 D b, 2s, o % (b)
25 ≧ Mt ≧ 5g/d (c) 35≧W
2.4J ((b) 5D≧△S≧2.0% (however, in (a) to above), MDE has intermediate elongation,
Mt represents the terminal modulus, W represents the amount of work, and ΔS represents the dry heat shrinkage rate, and these definitions follow the description in the text. ) (2)i) IV is 08 or more, birefringence (△n) is 25
xiO' or more and a density (ρ) of 1,338 or more, polyester undrawn yarn is stretched at a stretching ratio of 09, which is less than its limit stretching ratio of 0395%, and then subjected to relaxation treatment of less than 15% or tension treatment of less than 50%. Then, by winding it up, obtain a drawn yarn having the following characteristics (I T/D 7.5 g/d (B)
1 8 ≧ DE ≧ 1 6 %\) 150
2M i≧90g/d −) 15≧M t g, / d u) Twisting the above-mentioned drawn yarn with a twist coefficient of 2000 to 2500 to form a raw cord; 250-26 after giving
40≧Mnhq3. A method for producing a polyester tire cord, characterized in that the treated cord has a characteristic of 0%. (However, in (a) to (e) above, T/D is strength, DI
U represents the elongation at break, Ml represents the initial tensile resistance, and Mt represents the terminal modulus, and these definitions follow the description in the text. )