JPS5840585B2 - Polyamide cage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aromatic polyamide polymer composition with improved equipment corrosion resistance.

Molded articles such as fibers and films made of aromatic polyamide polymers have useful properties such as excellent mechanical properties and thermal properties. It is known that it can be obtained by wet or dry spinning.

The equipment corrosivity during spinning of the concentrated sulfuric acid solution increases as the concentration of sulfuric acid used is lower, or as the polymer concentration is lower and the proportion of sulfuric acid is higher, or as the temperature is higher.

Conventionally, it has been widely practiced to spin low-concentration solutions at relatively low temperatures in order to keep equipment corrosion to a low level. It has been found that there is an improvement in the performance of the spinning process, and there is a need for another method for suppressing equipment corrosion during high temperature spinning.

Therefore, we investigated ways to improve the corrosivity of the equipment and facilitate high-temperature spinning.We found that adding a specific amount of a specific additive to the spinning stock solution could have a negative impact on the properties of the resulting molded product. It was found that the corrosiveness of the device could be improved without adding any additives, leading to the invention of the present application having the following configuration.

LiXNa in concentrated sulfuric acid solution of aromatic polyamide polymer
XKX BeXSnXZnXMgXFezCuXCa One or more metal sulfates selected from the group 0.01 to 0
．． An aromatic polyamide-based polymer composition characterized by containing 4 wt%.

Conventionally, copper sulfate has been known to be used as an anticorrosive agent when cleaning spinnerets with sulfuric acid, but there is no knowledge of adding copper sulfate to polymer solutions, and furthermore, there is no knowledge that copper sulfate can be used to prevent corrosion during spinning. Therefore, no consideration has been given to adding additives to the polymer solution.

On the other hand, it was announced in 1986-258 that sodium sulfate, potassium sulfate, and lithium sulfate may be included in the spinning stock solution.
00 and Japanese Patent Publication No. 50-8474, these publications contain a large amount of sulfate of 1 to 15 wj'% or 2 to 3 wt% of the solvent to improve the mechanical properties of the molded product. It is stated that it may contain.

However, upon investigation by the inventor of the present application, it has been found that when such a large amount is contained, the mechanical properties of the resulting molded article are adversely reduced.

For example, as described in Example 2 below, a yarn obtained from a spinning dope containing 0.5 W t qb gold of sodium sulfate showed a strength decrease of about 20 factors.

In addition, in order to improve the corrosion resistance of the equipment, which is the purpose of the present invention,
It is not necessary to contain as much as in the known example,
Addition of 0.01 to 0.4 wt is sufficient, approximately o,
There is no difference in the effect when the amount is 1 wt % or more, and no advantage can be found in adding a large amount.

The additives used in the present invention are Li and NaXK.

It is a sulfate of a metal selected from the group Be, SnXZnXMgX FeXCuXCa.

Preferably, a water-soluble sulfate salt that is soluble in concentrated sulfuric acid and can be removed from the molded article by washing with water, that is, LiX
Na.

A sulfate of a metal selected from the group of KXBeXSn, Zn, MgXFe, and Cu is preferable.

More preferably, a sulfate of a metal selected from the group of NaX5nXZn and Cu is preferred.

The content of the additive in the present invention is 0.00% of the polymer solution.
01 to 0.4 wt, preferably 0.01 to 0
．． 2 wt%.

As mentioned above, if the amount of the additive is too small, the intended effect of the present invention cannot be obtained, while if it is too large, the mechanical properties of the molded article will deteriorate.

The concentrated sulfuric acid solution of the aromatic polyamide polymer in the present invention is a solution consisting essentially of one or more aromatic polyamide polymers and one or more concentrated sulfuric acid solvents, but may contain other known additives (e.g. , lithium chloride, calcium chloride, etc. (excluding sulfates specified in the present invention).

Aromatic polyamide-based polymers are fully aromatic homopolyamides, copolyamides, or polyamides obtained by copolymerizing non-aromatic groups with the fully aromatic polyamides, and are polymers that are dissolved in a concentrated sulfuric acid solvent and spun out. , for example, poly P-benzamide, poly P-phenylene terephthalamide,
Poly P-phenylene terephthalamide/N -N'-
These include ethylene bis-4-aminobenzterephthalamide copolymer.

The polymer composition according to the present invention can be effectively used as a spinning stock solution that can be spun into molded products such as films, fibers, fibrids, etc. by wet or dry-wet spinning, thereby preventing equipment corrosion during spinning. is greatly improved.

In particular, from high concentration solutions (e.g. 15 wt1 or more) to 65
It is effectively used in cases where large equipment corrosion occurs, such as when spinning is carried out at high temperatures of ℃ or higher.

A further advantage of the present invention is that the properties of the molded article do not deteriorate due to the inclusion of additives in the polymer solution.

Therefore, spinning from a highly concentrated solution becomes easy, and it becomes easy to obtain an aromatic polyamide polymer molded article with even better physical properties.

The sulfate may be removed from the molded article obtained from the composition according to the present invention by washing with water or the like after spinning.

Next, it will be explained in detail using examples.

The intrinsic viscosity (7 inh) was measured at 30° C. by dissolving 0.5 g of polymer in 100 CC of 98 wt'% sulfuric acid.

The strength of the fibers was measured for single yarns using a Tensilon tensile tester (manufactured by Toyo Baldwin).

The sample length was 100 mm, and the tensile speed was 50 threads/min.

Example 1 Add 0 of the sulfates listed in Table 1 to 100 cc of concentrated sulfuric acid of 98.7 wt.
．． 115g was added and heated to 85°C to dissolve.

Next, poly P-phenylene terephthalamide (η
inh 5.3) 46 & was mixed and stirred for 2 hours to form a dope.

After degassing the dope under reduced pressure, a corrosion test on a 5uS316 stainless steel specimen was conducted in the following manner.

The corrosion test consisted of 8 test pieces measuring 25 mm vertically, 20 mm horizontally, and 3 mm thick.
96 hr in doping of 50rILl held at 5°C
The degree of erosion due to corrosion was determined by dividing the weight difference between the test pieces before and after the corrosion test by the surface area of the test piece, and calculated as the erosion length in −years.

The obtained erosion degree is shown in Table 1 in comparison with the dope to which no sulfate was added.

It has been found that the additive-containing dope according to the present invention has a remarkable corrosion resistance effect.

Example 2 9s, 300cc of 7 wt% concentrated sulfuric acid with Na2SO
4 was added in the amount shown in Table 2 (amount relative to the dope), heated to 85° C., stirred, and dissolved.

Next, poly P-phenylene terephthalamide (η1
nh5.3) were mixed and stirred for 2 hours to form a dope.

After degassing the dope under reduced pressure, a corrosion test on 5 us 316 stainless steel was conducted in the same manner as in Example 1.

The above dope, which had not been subjected to the corrosion test, was transferred to a small spinning machine, extruded through a 0.06 mmφ, 60-hole spinneret at about 85°C, passed through an air space of about 5 cm, and then wet-dry spun in water at 10°C.

The thread wound on the bobbin at a winding speed of 100 m/min is
-Night 0. It was immersed in an aqueous solution of IN NaHCO3, then in double water, and then air-dried.

The results of the corrosion test and the strength of the obtained threads were as shown in Table 2.

Note that when the amount of Na2SO4 added was 2.6wt4, the viscosity of the dope was so high that spinning was impossible.

If the amount added is too small (0.005 wt %), the anti-corrosion effect will not be sufficient, while if the amount added is too large (0.5 wt %), the yarn strength will be greatly reduced, both of which are not preferred.

Sufficient anti-corrosion effects were obtained at the added amounts according to the present invention, and the strength of the obtained yarns was also the same or slightly better, with no adverse effects caused by the additives.

Example 3 SnSO4 was added to 100cc of concentrated sulfuric acid of 98.7wt4.
115g was added, heated to 85°C, stirred, and dissolved.

Next, poly P-phenylene terephthalamide (7i
nh5.3) 46 g were mixed and stirred for 2 hours to form a dope.

After degassing the dope under reduced pressure, a corrosion test on 5us316 stainless steel was conducted in the same manner as in Example 1, except that the dope temperature was 100°C.

The obtained erosion degree is shown in Table 3 in comparison with the case where 5nSo was not added.

Even in sulfuric acid dope at 100℃, Provides remarkable corrosion resistance.

5nSo4 is

Claims (1)

[Claims] 1. In a concentrated sulfuric acid solution of an aromatic polyamide polymer, Li
XNalKXBeXSnXZnXMgXFe. An aromatic polyamide polymer composition containing 0.01 to 0.4 wt% of one or more metal sulfates selected from the group CuXCa.