US 3907743 A
This invention involves the melt spinning of polyamide yarn containing 0.001 to 0.05% by weight of the polyamide of one or more compounds from the following group: magnesium acetate, magnesium chloride, magnesium bromide, magnesium nitride; and 0.05% to 5% by weight of one or more compounds from the following group: dithiocarbamate metallic salts, thioethers of fatty acids, 2-mercaptobenzimidazol, 2-mercaptobenzimidazol metallic salts, and 2,2'dibenzimidazol disulfide. The added compounds reduce the accumulation of carbonized material at the spinneret orifice.
Description (OCR text may contain errors)
United States Patent 11 1 Goto et a1.
1 51 Sept. 23, 1975 MELT SPINNING METHOD or POLYAMIDE YARN  lnventorsz Michio Goto; Shogo Ito; Atuio Tanaka, all of Mihara, Japan  US. Cl. 260/45.75 C; 260/457 R; 260/4575 W; 260/4585 S; 260/458; 260/45.9 R  Int. C1. C08G 85/00  Field of Search 260/4575, 45.85, 45.8, 260/459  References Cited UNITED STATES PATENTS 2,705,227 3/1955 Stamatoff 260/457 FOREIGN PATENTS OR APPLlCATIONS 650,173 1/1965 Belgium 260/4575 842,271 7/1960 United Kingdom 260/4575 969,154 12/1950 France 260/459 1,159,299 6/1958 France 260/4575 Primary Exami/1erV. P. Hoke Attorney, Agent, or FirmRichard A. Anderson  ABSTRACT This invention involves the melt spinning of polyamide yarn containing 0.001 to 0.05% by weight of the polyamide of one or more compounds from the following group: magnesium acetate, magnesium chloride, mag nesium bromide, magnesium nitride; and 0.05% to 5% by weight of one or more compounds from the follow ing group: dithiocarbamate metallic salts, thioethers of fatty acids, Z-mercaptobenzimidazol, 2- mercaptobenzimidazol metallic salts, and 2,2'dibenzimidazol disulfide. The added compounds reduce the accumulation of carbonized material at the spinneret orifice.
4 Claims, N0 Drawings 1 MELT sPINNINo METIIoD or POLYAMIDE YARN BACKGROUND OF TI-IE INVENTION This invention is concerned with the melt spinning method of polyamide. Especially, this invention is the method for preventing a single filament break produced by accumulation of carbonized volatile materials such as 'monomergand oligomer on the spinneret surface during the melt spinning of polyamide.
. During. the-prolonged melt spinning ofpolyamide, volatile materials, such as monomer and oligomer adhere to the spinneret surface; after a time they are oxiclized in high temperature surroundings and accumulate as carbonized material. This carbonized material accumulated on the spinneret surface produces a bend ing phenomena of the molten stream of polyamide during spinning. The end result produces drips or single filament breaks caused by the enlarging, bending and adherence of the melted polyamide on the spinneret.
For this reason, spinning must be regularly stopped for cleaning of the spinneret surface which reduces productivity.
Presently, there are various methods existing for elimination of these defects. For example, there are methods concerned with spinning equipment, such as sealing of the surface below the spinneret with nonreactive gas, changing spinneret capillary shapes, or applying silicone oil on the spinneret surface. But these methods were not giving the desired effect for the prevention of single filament breaks.
SUMMARY OF THE INVENTION This invention is the mixing of a magnesium salt and a sulfur containing organic ionic compound into the polyamide to reducethe accumulation or carbonized materials on the surface of the spinneret being there fore effective in preventionbf a single -filament break.
In other words, this invention" is' the melt spinning method of polyamide characterized by the meltspinning of yarn with polyamide containing 0.00l to 0.05% by weight of the polyamide'of a compound selected from one or moreof the following: magnesium acetate, magnesium chloride, magnesium bromide, magnesium nitride; and 0.05 to 5% by weight of a compound selected from one type or more of the following group: dithiocarbamate metallic salts, thioethers of fatty esters, 2-mercaptobenz'imidazol, 2- mercaptobenzimidazol metallic salts, and 2,2- dibenzimidazol disultide. I
DESCRIPTION or PREFERRED EMBODIMENTS This invention is concerned with a superior effectiveness in preventing a single filament break during the melt spinning of polyamide by using especially magnesium salt and sulfur containing ionic organic compounds as previously described. The other magnesium salts, for example, combination of magnesium oxide,
magnesium sulfide, etc. with the abovedescribed sulfur containing ionic organic compounds will not give effectiveness in preventing a single filament break.
Independently applying the magnesium salts or sulfur containing ionic organic compounds used in this invention will not give full effectiveness.
A remarkable effectiveness is obtained in prevention of single filament breaks when applying the combination of both compounds of this invention.
In this invention method, the magnesium salt addition is 0.001 to 0.05% by weight to polyamide. In case of using less than 0.001% by weightresults in easy oc currence of a single filament break during the spinning. The use of higher than 0.05% by' weight will reduce polymerization rate when added during the polymerization, or lower the viscosity when impregnated onto chips during the spinning.
The dithiocarbamate salts used in this invention method are, for example, the sodium, zinc, copper, selenium, thallium salts of dithiocarbamate, such as dimethyl dithiocarbamate, diethyl dithiocarbamate, di-nbutyl dithiocarbamate, ethyl phenol dithiocarbamate.
The 2-mercaptobenzimidazol metallic salts are, the zinc, copper and magnesium salts of 2- mercaptobenzimidazol. And, for example, the thioethers of fatty esters are dilauryl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, etc. The amount of addition of these organic compounds is 0.05 to 5% by weight to polyamide. Use of less than 0.05% by weight resultsin insufficient effectiveness in prevention of single filament breaks. Use of more than 5% by weight affects physical properties of yarn, i.e. strength is lowered, therefore, such large amounts are not favorable.
In this method, previously described magnesium salts and organic compounds can be incorporated into the raw material of polyamide before polymerization, or added during polymerization, or mixed with polyamide chips. It follows that these additive containing polyamides will be melt spun, but the melt spinning method is not critical. Either a melter type or extruder type can be used. The extruder type is preferred because it will result in uniform yarn quality.
The polyamides used in this invention can be, for example, the polyamide from w-lactam such as poly-e c'aprolactam, poly-w-nonamide, poly-m-lauryl lactam, also the polyamides obtained from diamines and cheerboxylic acids and their copolymers or blends of various polymers of polyhexamethyleneadipamide, polyhexamethylenesebacamide, polyhexamethylene isophthalamide, when these polymers can contain a luster agent, heat stabilizer, ultra violet light stabilizer, antistatic electricity agent, terminator, and optical brightner.
Based on this invention that the bending phenomena of melted polyamide on the spinneret surface is greatly reduced, furthermore remarkable extension of time for a single filament break occurs which results in a remarkable'extension of time for spinneret surface cleaning cycle.
EXAMPLES The actual examples are as follows. ln the inherent viscosity given in the examples were calculated from the viscosity measurement in meta-cresol at 30C., and the parts given in examples are all on the weight basis.
ACTUAL EXAMPLES 1-5, COMPARISON EXAMPLE l-6 After polymerizing parts of the e-caprolactam, and 1 part water for four (4) hours in the autoclave at 265C, various magnesium salts and sulfur containing organic ionic compound were added, then nitrogen blanket pressure was gradually reduced.
Chips of poly-e-caprolactam (inherent viscosity 1.42) using 40 grams per denier ratio extruder chips were spun with the following conditions: 280C. spinning temperature, 600 m/minute spinning speeds, 28C. cooling air temperature and using a spinneret having 0.6 l/d ratio capillaries. The measurement of occurrence time for the bending or a single filament dithiocarbamate metallic salts, thiodialkanoic acid esters, Z-mercaptobenzimidazol, Z-mercaptobenzimidazol metal salts,
break was made on the first occurrence time with using d a prev1ously silicone oil sprayed spinneret during spinzgtdib i i d i lfl nmg. The average values of measurements are shown in Table I. For comparison, poly-e-caproamide is ob- The method of clalm 1 wherein the p y d tained (inherent viscosity, 1.45) without using above P y P described magnesium salts or sulfur containing organic A method to reduce bullddlp of carbonized mateionic compounds. The first occurrence time of the on the Surface ofaspmneret during Spinning of y bending or a single filament break was measured. The thetic lineal Poll/amides having ecurring amide groups average values of measurement are shown in Table l. conslstmg 0f TABLE 1 Occurrence Occurrence Time of Actual Magnesium lon Contained Time of Single Filament Example Salt (Part) Organic Compound (Part) Bending (Hour) Break (Hour) 1 Magnesium Acetate 0.05 Zinc diethyl dithiocarbamate 0.5 32 55 2 Magnesium Nitride 0.03 Z-mercaptobenzimidazol 0.3 33 58 3 Magnesium Chloride 0.05 Diluuryl-3,3-thimlipropionate 0.5 37 63 4 Magnesium Bromide 0.01 copper Z-mercaptohenzimid:ilol 0.4 29 56 5 Magnesium Bromide 0.01 2,2'-diben7.imidazol disulfide 0.2 28 55 Comparison Example 1 None None 7 l3 2 Magnesium Nitride 0.03 None 14 23 3 Magnesium Chloride 0.05 None 28 4 None 2.mcrcaptobenzimidazol .3 16 30 5 None Dilauryl 3,3'-thiodipropionate 0.5 15 29 6 Magnesium Oxide 0.05 Zinc diethyl dithiocarbamate 0.5 15 27 From Table 1, it is shown the remarkable extension of a single filament break occurrence time. Again it is shown that use of other magnesium salt as used in this invention, such as magnesium oxide with sulfur containing ionic organic compound will not give the supe-' rior effectiveness as the result obtained from this invention.
We claim: 1. A method to reduce build-up of carbonized material on the surface of a spinneret during spinning of synthetic linear polyamides having recurring amide groups consisting of spinning a polyamide composition comprising a polyamide containing from about 0.001 to about 0.05% by weight of the polyamide of a compound selected from the group consisting of magnesium acetate, magnesium chloride, magnesium bromide, and magnesium nitride, and
from about 0.05 to about 5% by weight of the polyamide of a compound selected from the group consisting of spinning a polyamide composition comprising a polyamide containing from about 0.001 to about 0.05% by weight of the polyamide of a compound selected from the group consisting of magnesium acetate, magnesium chloride, magnesium bromide, and magnesium nitride, and
from about 0.05 to about 5% by weight of the polyamide of a compound selected from the group consisting of the sodium, zinc, copper, selenium and thallium salts of dithiocarbamate, dilauryl 3,3'-thiodipropionate, distearyl 3,3 '-thiodipropionate, Z-mercaptobenlzimidazol, zinc, copper and magnesium salts of 2-mercaptobenzimidazol, and 2,2-dibenzimidazol disulfide.
4. The method of claim 3 wherein the polyamide is polycaprolactam.