KR100391974B1 - Aromatic polyamide pulp, method of manufacturing the same and refiner disk therefor - Google Patents

Abstract

PURPOSE: Provided is an amide pulp which involves elongated length, and enhanced floatation. CONSTITUTION: A pulp precursor is circularly pulped two or more times using a double disk refiner structure where two refiners are arranged by the distance of 4/1000-6/1000 inch. With the refiner, the width of crest is established to be 3-7.5mm, the depth of trough to be 3-7.5mm, the distance between the crest neighbors to be 0.5-5.8mm, and the curvature of the crest to be 0.2-0.4. The resulting aromatic polyamide pulp has an intrinsic viscosity of 3.0 or more, a crystallization degree of 40% or more, and a floatation of 500ml or more, and 50% or more thereof has a length of 8.6mm or more.

Description

Aromatic Polyamide Pulp, Method for Making the Same, and Refiner Disc for the Production thereof

The present invention relates to refiner discs capable of improving the length and subcentering force of the pulp when used in the pre-pulp pulping process in producing aromatic polyamide pulp. The present invention also relates to a process for producing aromatic polyamide pulp with improved length and floatation using the refiner disk.

Aromatic polyamide pulp is widely used as brake linings and reinforcements. Such aromatic polyamide pulp is produced by various production methods.

Prior arts for preparing aromatic polyamide pulp include US Pat. Nos. 3,767, 756 and 5,028,372.

U.S. Patent No. 3,767,756 describes a polymer by reacting an aromatic diamine and an aromatic dieside chloride in a reaction solvent, melt spinning the same to prepare a thread having an oriented molecular chain, and then mechanically cutting or pulverizing the yarn. To prepare an aromatic polyamide pulp. Such a method has a disadvantage in that the process is complicated and expensive because of pulping after spinning.

In addition, US Pat. No. 5, 028, 372 describes the preparation of polymers by reacting aromatic diamines and aromatic dieside chlorides in a reaction solvent, and cutting, aging, milling and refining the polymer to separate the pulp from the belt solvent in a belt filter. To prepare an aromatic polyamide pulp.

This method simplifies the process by reducing the spinning process in US Pat. No. 3, 767, 756 and reduces the cost, but omitting the spinning process lowers the orientation and strength of the pulp. In addition, since the polymer is pulverized by the milling process immediately after the extraction process without the extraction process, hydrogen bonds between the molecular chains of the polymer are cut, and thus pulp of good physical properties cannot be produced. In addition, the refining process was so rapidly applied that pulp of good fibril development and long length could not be produced.

The present invention uses refiner discs to improve the length and subconcentricity of the pulp by solving conventional problems in producing aromatic polyamide pulp by polymerization, cutting, ripening, milling and refining processes.

The refiner disk of the present invention will be described in more detail.

The refiner disk of the present invention has a peak width (d) of 3 to 7.5 mm, a valley depth (h) of 3 to 7.5 mm, a peak (w) of a peak of 0.5 to 5.8 mm, and a peak curvature ( R) is 0.2-0.4. At this time, the curvature R of the mountain is a value obtained by dividing the curved surface length of the mountain by the width of the mountain (w).

Conventional refiner discs have an acid angle, i.e., no curvature in the acid. Refiner discs with angled acids cannot cut pulp during the refining process to produce long pulp.

The refiner disk of the present invention reduces the cutting of the pulp, and improves the role of rubbing each other between the pulp, it is possible to produce a pulp with a long length and improved buoyancy.

In the present invention, a double disc liner manufactured by arranging two refiner discs having a curvature so as to have a spacing of 4/1000 to 6/1000 inches as described above is used.

When the acid curvature R is 0.4 or more, the frictional force between the pulp and the disk decreases, and the refining effect is lowered. When the acid curvature R is 0.2 or less, the pulp is increased and a long pulp cannot be obtained.

If the disk spacing is less than 4/1000 inches, the length of the pulp is short, and if the thickness is more than 6/1000 inches thick pulp is produced.

The process for producing an aromatic polyamide using the refiner disk of the present invention described above will be described in more detail.

Using an imide solvent or urea solvent to which Lewis acid and / or an inorganic salt was added as a polymerization solvent, the aromatic diamine and the aromatic dieside compound were continuously polymerized in a continuous polymerizer, and the polymer was discharged by a continuous aligner to orient the polymer. The oriented polymer is cut in a cutter to a size of 3 cm wide, 2 cm long and 1 cm thick. After slicing the cut polymer in water at 80 ° C. for at least 8 hours to extract a solvent, the slurry was pre-pulled with a concentration of 4% or less by primary grinding (milling) with a double disk having a disk spacing of about 1 mm. do.

The slurry of the prepared pre-pulp is pulped with the double disk refiner of the present invention. At this time, the rotation speed of the disk is 1200 rpm is suitable.

The refining (pulping) process is repeated and repeated two or more times.

At least 50% of the aromatic polyamide pulp produced by the process of the present invention has a length of at least 8.6 mm. In addition, the intrinsic viscosity is 3.0 or more, the crystallinity is 40% or more, and the buoyancy force is 500 ml or more.

Here, the sub-center force is a value obtained by dissolving 1 g of dried pulp in 1,000 ml of water at 10,000 revolutions, then putting it in a 1,000 ml volume cylinder and measuring the volume of pulp after 2 minutes.

Example 1

When 1000 Kg of N-methyl-2-pyrrolidone reaches 80 ° C., 80 Kg of CaCl ₂ is added to dissolve completely. 48.67 Kg of P-phenylene diamine was added to this polymerization solvent to dissolve to prepare a premixed solvent. This is also called premix. The premix is fed to the mixer at a rate of 1128.67 g / min at 5 ° C using a metering pump. At the same time, molten terephthaloyl chloride is added to the mixer at a rate of 27.41 g / min and mixed. This produces the first polymer. The first polymer prepared was cooled to 5 ° C. and fed to a continuous polymerizer at a rate of 1156.8 g / min. At this time, molten terephthaloyl chloride was simultaneously added at a rate of 63.95 g / min. The residence time in the continuous polymerizer was discharged to the continuous disperser while maintaining the jacket temperature at 35 ° C for 5 seconds. This discharged polymer is also called a prepolymer.

An oriented polymer having an I.V of between 3.5 and 4.5 can be obtained while orienting the discharged prepolymer in a continuous orientation device.

The oriented polymer is cut into 3 cm width, 2 cm length and 1 cm thickness, left for 8 hours in water at 80 ° C to extract the solvent, and then first ground with a double disk mill with a disc spacing of 1 mm to give a concentration. A 2% pre-pulp slurry is prepared. The prepared slurry is agitated by edge data in a reservoir and transferred to a refiner of a double disc by a metering pump.

The width (d) of the refiner disc mount, the gap (w) and the height (h) of the mount are 4.2 mm, respectively. In addition, the spacing between refiner discs is 4/1000 inches and the curvature R of the disc mount is 0.2. The rotation speed of the refiner is 1,200 rpm.

The pre-pulp fed to this double refiner disk is refined twice to produce an aromatic polyamide pulp. The results of measuring the length and the buoyancy force of the prepared pulp are shown in Table 1.

Example 2

It is the same as that of Example 1 except having adjusted the space | interval between refiner discs 5/1000 inch, and the curvature of a disc peak to 0.3.

Example 3

The same procedure as in Example 1 was made except that the spacing between the refiner disks was 6/1000 inches and the curvature of the disk mounts was 0.4.

Comparative Example 1

It is the same as that of Example 1 except having set the spacing between refiner disks to 2/1000 inch, and the curvature of a disk mount to 0.1.

Comparative Example 2

It is the same as that of Example 1 except having set the spacing between refiner disks to 7/1000 inch, and the curvature of a disk mount to 0.5.

<Table 1>

1 is a partial cross-sectional view of a refiner disk

2 is a partial side view of the refiner disc mount

(d is the width of the mountain, r is the length of the mountain, w is the distance between the mountains, and h is the height of the mountains.)

Claims (4)

Aromatic polyamide pulp, characterized in that the intrinsic viscosity is at least 3.0, the crystallinity is at least 40%, the buoyancy force is at least 500 ml, at least 50% of the pulp has a length of at least 8.6 mm. In preparing the aromatic polyamide pulp by the polymerization, cutting, ripening, milling and refining process, the solvent in the polymer cut in the ripening process is extracted and the width of the acid is circulated twice or more by circulating the pre-pulp slurry prepared in the milling process. (d) Refiner disk with 3 to 7.5 mm, bone depth (h) between 3 and 7.5 mm, acid and mountain spacing (w) between 0.5 and 5.8 mm, and mountain flexion (R) between 0.2 and 0.4 A method for producing an aromatic polyamide pulp, characterized in that the two are pulped with a double disk refiner arranged at intervals of 4/1000 to 6/1000 inches. A process for producing aromatic polyamide pulp according to claim 2, wherein the slurry concentration of the pre-pulp is 4% or less. The width (d) of the mountain is 3 to 7.5 mm, the depth of the valley (h) is 3 to 7.5 mm, the distance (w) between the mountain and the mountain is 0.5 to 5.8 mm, and the curvature of the mountain (R) is 0.2 to 0.4 Refiner disc for producing aromatic polyamide pulp, characterized in that.