JPS6028937B2 - Polyester sewing thread with excellent heat resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester sewing thread having excellent heat resistance.

Polyester sewing thread manufactured from filament yarn obtained by melt-spinning and drawing polyethylene terephthalate has high strength, good dyeability, high color fastness, excellent dimensional stability, and long-term durability. Because it has excellent properties such as less loss of strength, it has come to be used as a substitute for traditional cotton Katan thread in sewing work in the clothing field.

Since polyester sewing thread is inexpensive, it is also used in large quantities as a sewing thread for industrial products. However, conventional polyester sewing thread still has insufficient heat resistance, and when sewing at high speeds of about 400 pm or sewing thick fabrics, the sewing thread may break due to friction between the sewing thread and the fabric or sewing thread. The temperature may rise to a high temperature close to the melting point, resulting in frequent fusing and breakage of sewing thread, which significantly reduces sewing efficiency.・In addition, in industrial products that are sewn under harsh conditions that are close to the sewing limit, the sewing thread has a history of high temperatures during sewing and has deteriorated due to heat, making it impossible to withstand long-term use and causing the seams to tear prematurely. Sometimes. As mentioned above, conventional polyester sewing threads have insufficient heat resistance, so there has been a demand for improved heat resistance. In addition, as a means to improve the high-speed laminability of the secondary polyester sewing thread, for example, a method of reducing friction by reducing the twist angle between the sewing thread and the constituent single yarn filaments (Tokukan Sho 52-27847 However, methods of improving high-temperature dynamic friction characteristics using a silicone oil (see Tokusekki No. 52-8198) are known.
None of these known methods improves the heat resistance of the sewing thread body to improve high-speed sewing performance.

The inventors of the present invention have obtained a number of new findings as a result of intensive research into a method for reducing fusing thread breakage of sewing thread by increasing the heat resistance of polyester sewing thread bodies. Conventionally, there has been no device that accurately measures the fusing temperature of sewing thread, but the present inventors first created a device that measures the fusing temperature of sewing thread.

The outline of the fusing temperature measuring device will be explained below with reference to FIG. In FIG. 1, 1 is a cylindrical heater with an inner diameter of 8 and a length of 15 mm, and a 0.1 g nod army weight 4 is passed through the cylindrical heater 1 and attached to one end of the sewing thread 2 via a pulley 3. The other end of the sewing thread 2 is connected to the stress detector 5. Then, the temperature inside the cylindrical heater 1 is raised at a rate of 24oC/min using a temperature regulator (not shown), and when the sewing thread 2 is cut and the scale of the stress detector 5 shows 0, The temperature is the melting temperature. Note that 6 is a thermocouple for measuring the temperature inside the cylindrical heater 1, and the thread tension measured by the stress detector 5 and the temperature measured by the thermocouple 6 are plotted on the X-Y axis. When they measured the fusing temperatures of various polyester thin threads with different melting points using the above fusing temperature measurement device, they found that fusing temperatures do not necessarily correspond to melting points, and this finding is completely It was something that could not have been predicted.

Therefore, in order to further investigate the dependence between the fusing temperature and the properties of polyethylene terephthalate that constitutes the sewing thread, we used a computer to analyze the relationship between a large amount of data on various properties and the fusing temperature. Intrinsic viscosity of sewing thread IV and molar percentage of diethylene glycol
They discovered that (DEG) is combined with 3XI).

Fusing temperature = 46.91V - 3.5 leg EG 1216.7...
(1) The intrinsic viscosity (IV) is a value measured using a mixed solvent of phenolnotetrachloroethane=6/4.

In addition, the content mol% (OEG) of diethylene glycol is
This is the mol% content of diethylene glycol based on the ethylene glycol component in polyethylene terephthalate, and is a value measured by the following method. That is, 2 cc of methanol and 9 parts of polyethylene terephthalate (or sewing thread) were sealed in a glass ampoule,
250 qo of this glass ampoule in an autoclave,
After heating for 6 hours and cooling, the sample was taken out, the glass ampoule was opened, and the decomposition liquid was developed using a gas chromatograph.
The temperature was raised between 100 and 210°C at a rate of 6°C/min, the peak areas based on ethylene glycol and ethylene glycol were determined from the obtained chart, and DEG was determined from the ratio of ethylene glycol area/ethylene glycol area. demand. The conditions for the gas chromatography above are:
A commercially available packing material (60-80 mesh Camerite CS as a carrier and PEG2
A flame ionization detector (Em) was used as the detector, and the ejection temperature was set at 22,000. Now, when we measured the fusing temperature of commercially available polyster sewing thread, the highest value was 243°C, so in order to obtain a sewing thread with excellent heat resistance that exceeds the fusing temperature of 243°C, the above yl) The formula can be rewritten as follows. 46
-91V1. 58DEG+216-7>243 Therefore,
The relationship between IV and DEG must satisfy the following formula {1}. 46-91V-3-5
9DEG>263...{11 By the way, the above verse yl
As can be seen from the method, in order to increase the fusing temperature, it is sufficient to select a sewing thread with a large intrinsic viscosity IV and a small DEG, but there is a limit in view of the practical values of the intrinsic viscosity and DEG.

This invention has been achieved based on the above findings.

That is, in this invention, the filament constituting the sewing thread made of polyethylene terephthalate is [1) 46-
91V-3-58DEG>26.3'21 0.5<D
EG<3.0{3'IV<1.0 (where, V is the intrinsic viscosity, and DEG is the molar percentage of the ethylene glycol content relative to the ethylene glycol component in the polyethylene terephthalate constituting the thin thread).
This polyester sewing thread has excellent heat resistance and is characterized by having an IV value and a DEC value that satisfy the formula.

In order to set the intrinsic viscosity IV of sewing thread to 1.0 or more, the degree of vacuum and temperature must be extremely high in the final stage of the polymerization process, and molecular chain scission due to oxidation and decomposition must be avoided in the spinning process. Therefore, it is not realistic to desire a high IV of sewing thread, and the cost increases.

Therefore, a realistic range of IV is 1.0, preferably 0.6 to 1.0. Diethylene glycol is a product produced by the reaction between ethylene glycols during the polymerization process of polyethylene terephthalate, but DE
It is difficult to reduce the q value to 0.5 or less based on current polymerization technology, and in order to improve heat resistance in the region of DEC > 3.0, the IV must be considerably increased, which is economically disadvantageous. becomes.

Therefore, as mentioned above, it is limited to 0.5<DEG<3.0. FIG. 2 is a graph showing the relationship between IV and DEG at each melting temperature calculated using the above formula (1), and the area surrounded by the dotted line shows the range according to the present invention. 46.91V-3 in equation (1) explained above
．． The larger the value of pentapod EG (hereinafter referred to as A value), the better the heat resistance of the sewing thread. However, the combination of the above IV and DEG is suitable for the heat resistance required depending on the purpose of use of the sewing thread, and its heat resistance. The choice should be made in relation to manufacturing costs.

For example, in the case of thick industrial sewn products, IV=0.78
~0.81, DEG = 0.8 ~ 0.9 is suitable from the viewpoint of heat resistance, strength, and manufacturing cost, and in the case of thin sewn clothing products, IV = 0. Iso~0.70, DE
A combination of G=0.9 to 1.2 is suitable. As mentioned above, in order to roughly adjust the intrinsic viscosity IV of polyethylene terephthalate and the content mol% of diethylene glycol (DEC) within the desired range, it can be obtained by appropriately setting the known polymerization conditions in the polymerization process of polyethylene terephthalate. .

The intrinsic viscosity depends on the polymerization time, polymerization temperature, hatching speed, degree of pressure reduction during polymerization, type of catalyst, amount added, etc.
The intrinsic viscosity tends to increase as the polymerization temperature, speed, and amount of catalyst added increase. The intrinsic viscosity can also be increased by phase polymerization. The DEG value depends on the terminal acid value, the proton concentration of the additive, the type of catalyst, etc., and when the terminal acid value and the proton concentration of the additive are lowered, the DEG value increases.
The G value becomes small, and when a compound such as antimony, germanium, titanium, etc. is used as a catalyst, the DEG value becomes small.

As explained above, the present invention improves the heat resistance of the sewing machine thread by appropriately combining the IV value and DEq value of the sewing thread, and satisfies high-speed sewing performance. Heat resistance can be further improved synergistically by improving the oil agent, resin processing, etc.

Examples of the present invention will be described below.

Example '1' Production of polyethylene terephthalate 166 parts (by weight, same below) of terephthalic acid, 124 parts of ethylene glycol, 0.3 mol% triethylamine and 0.03 mol% antimony trioxide based on terephthalic acid. These were charged into an autoclave equipped with a fly mill, a distillation column, and a pressure regulator, and esterification was carried out at 240oo for 95 minutes while maintaining a constant pressure of 3k9/carp, and then 0.1 Yanagi Hg was added. 68 at 280oC under reduced pressure of
The polycondensation reaction was carried out for a minute, and the obtained polymer was placed on the side of the sample. It was set to 1.

In addition, 194 parts of dimethyl terephthalate, 135 parts of ethylene glycol, and 0.03 mol% based on terephthalic acid.
of manganese acetate and 0.05 mol% of antimony trioxide were added, and these were charged into an autoclave equipped with a sardine pestle and a distillation column, and transesterification was carried out at 180 to 190q0 for 2 field hours under normal pressure, and then trimethyl 0.04 mol% of phosphate was added and 2
8000, polycondensation reaction for 50 minutes, IV value 0.62, D
A polymer with an EG value of 0.9 was obtained.

Next, this polymer was subjected to solid phase polymerization at 240°C under a 0.1 side Hg vacuum, and the solid phase polymerization time of 8 hours was designated as sample N.
o. 2. Sample No. 1 from early childhood. It was set as 3. For comparison, the above sample M. A comparison sample was prepared by keeping the polycondensation time to 50 minutes in the production of Example No. 1. ■ Manufacturing of sewing thread The above sample No. Using Samples 1, 2, 3 and comparative samples, spinning and drawing were performed under the conditions shown in the table below to obtain 75 denier, 24 filament sewing thread yarn.

These sewing machine threads were first twisted at 80mm/m, then three threads were combined and twisted at 70mm/m, heat set, and then dyed (13000mm, 40 minutes). After that, it was finished with 3% IJ cone oil and then wound onto a sewing thread bobbin. {3
1 Sewability test of sewing thread A high-speed sewing machine with a lockstitch 77 plate type 1 manufactured by Singer Sewing Machine Co., Ltd. was used, the machine needle was DBI #14, and the sewing machine rotation speed was 400 pm.
, the number of stitches is 15 stitches/3 stitches, the needle thread tension is 10 threads, and the bobbin thread tension is 25 g.
Stack the pieces and sew the length phantom h 3 times in a row.If there is no thread breakage during this time, add 1 more piece of cotton cloth, stack 3 pieces of cotton cloth, sew 3 times in the same way as above, and increase the number of layers in sequence. Then, sewing was continued until thread breakage occurred.

Then, the number of healthy sheets was calculated by adding the converted value of the sewing length of the number of stacks that could be sewn completely with ah and the sewing length of the number of stacks that could be sewn at least once out of 3 times to create a phantom stitch. In this sewability test, three types of commercially available products were also tested as comparative examples. '4' Heat Resistance Test The above sewing thread was placed in a circulating dryer manufactured by Tabai Seisakusho and heated at a constant length of 240°C for 2 minutes. It is shown as heat resistance with a strength retention rate of .

Note that the strength retention rate (%) could not be measured for the comparison sample and the commercially available product because they were fused together.

As seen in the table above, there was no significant difference in the melting points of the sewing threads of the present invention, comparative samples, and commercially available products, but there was a difference in the fusing temperature, and it was found that the higher the fusing temperature, the greater the number of threads that could be sewn. It shows.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of the melting temperature measuring device, and FIG. 2 is a graph showing the relationship between the intrinsic viscosity and DEG mol% at each melting temperature. Figure 1 Figure 2

Claims (1)

[Claims] 1. The filament constituting the sewing thread made of polyethylene terephthalate is (1) 46.9IV-3.58D.
EG>26.3 (2) 0.5<DEG<3.0 (3) IV<1.0 (where IV is the intrinsic viscosity and DEG is the molar content of diethylene glycol relative to the ethylene glycol component in the polyethylene terephthalate that constitutes the sewing thread) A polyester sewing thread with excellent heat resistance, characterized in that it has an IV value and a DEG value that satisfy formula 3 (%).