阅读说明：本技术 磷酸化pbi纤维 (Phosphorylated PBI fibers ) 是由 布莱恩·P·希尔斯 格里高利·S·科普兰德 秦烽 于 2016-06-28 设计创作，主要内容包括：一种制备磷酸化聚苯并咪唑纤维的方法,包括以下步骤：将未处理的PBI树脂纺丝成PBI纤维；用磷酸处理PBI纤维,从而获得重量百分比1-25％磷酸APU的PBI纤维。本发明开发了PBI和PBI制品的新应用和新用途。(A method of making a phosphorylated polybenzimidazole fiber comprising the steps of: spinning untreated PBI resin into PBI fibers; the PBI fibers were treated with phosphoric acid to obtain PBI fibers of 1-25% phosphoric acid APU by weight. The invention develops new applications and new uses of PBI and PBI products.)

1. A method of making a phosphorylated polybenzimidazole fiber comprising the steps of:

spinning untreated PBI resin into PBI fibers;

treating PBI fibers with phosphoric acid, and

thus obtaining PBI fibers with 1-25% by weight phosphoric acid.

2. The method of claim 1, wherein the phosphoric acid is 10-85% by weight phosphoric acid (aqueous solution).

3. The method of claim 1, wherein the phosphoric acid is 40-60% by weight phosphoric acid (aqueous solution).

4. The method of claim 1, wherein the phosphoric acid is 50% by weight phosphoric acid (aqueous solution).

5. The method of claim 1, wherein the treatment is performed at a temperature in the range of 15-50 ℃.

6. The method of claim 1, further comprising applying tension to the fiber during the applying the acid.

7. A fiber prepared according to the method of any one of claims 1-6,

the fibers comprise a Polybenzimidazole (PBI) polymer having a phosphoric acid carry in the range of 4 to 20 weight percent, and

the fibers have a denier of no greater than 6 dpf.

8. The fiber according to claim 7, wherein,

the application in textile, machinery and plastic additives;

LOI (limiting oxygen index) is more than or equal to 47 percent;

the initial thermal decomposition temperature in the air is about more than or equal to 555 ℃; and/or

Which are staple or filament fibers.

9. The fiber according to claim 7, wherein,

the phosphoric acid is carried in the range of 12-20 wt%;

preferably, the phosphoric acid carry-over is in the range of 8-24 wt.%;

more preferably, the phosphoric acid carry-over is 17 wt%.

10. A yarn or nonwoven material comprising the fiber of claim 7.

11. A fabric, which is a woven or knitted fabric, comprising the yarn of claim 10.

12. A garment comprising the fabric of claim 11.

Technical Field

The present invention relates to polybenzimidazole fibers.

Background

In the article History and Development of Polybenzimidazole (History and Development of Polybenzimidazole) by E.J.powers and G.A.Serad (proposed and published in High Performance Polymers: the same High Performance Polymers: Their Origin and Development) at 4, 15 and 18 of 1986, pages 19-20 and Table XIII, a Polybenzimidazole (PBI) polymer is disclosed which has 27% by weight of phosphoric acid (H) absorbed (or carried (pick-up)) H.J.powers and G.A.Serad₃PO₄) And can be used as a fiber having excellent thermal oxidation stability. Powers and Serad teach on page 20 that phosphorylated PBI is prepared by soaking PBI membranes in 2% aqueous phosphoric acid.

To date, commercial polybenzimidazole fibers have been sulfonated. Such sulfonated PBI fibers have enjoyed great commercial success, for example, in firefighter turnout gear because they have LOIs (limiting oxygen index, ASTM D2863) of around 41.

In order to explore and develop new applications and uses for PBI and articles made from PBI, the present inventors discovered new, more commercially valuable phosphorylated PBI fibers.

Summary of The Invention

A fiber made from a Polybenzimidazole (PBI) polymer with phosphoric acid pick-up (APU) in the range of 1-25% (PBI-p fiber). The PBI-p fibers have an LOI of greater than or equal to 50% and/or an initial thermal degradation temperature of greater than or equal to 555 ℃ as determined by thermogravimetric analysis (TGA) in air at a heating rate of 20 ℃/minute. A method of making a phosphorylated polybenzimidazole fiber comprising the steps of: spinning untreated PBI resin into PBI fibers; the PBI fibers were treated with phosphoric acid to obtain PBI fibers of 1-25% phosphoric acid APU by weight.

Drawings

For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred; it should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

Fig. 1 is a TGA graph comparing the initial (or onset) thermal degradation temperatures of various PBI fibers at a heating rate of 20 ℃/minute in air.

Description of the invention

Polybenzimidazole (PBI) fibers are phosphorylated in the range of 1-25 percent by weight phosphoric acid (or 1-25 percent by weight phosphoric acid carry over (or APU)), and have thermal oxidative stability equal to or better than commercially available sulfonated PBI fibers (the ranges include all subranges subsumed therein). Hereinafter, the phosphorylated PBI fiber is referred to as PBI-p fiber, and the sulfonated PBI fiber is referred to as PBI-s fiber. In another embodiment, the PBI-p fibers have phosphoric acid APU in the range of 4-20% by weight. In yet another embodiment, the PBI-p fiber has 8-24% by weight phosphoric acid APU. In yet another embodiment, the PBI-p has a phosphoric acid carry-over in the range of 12-20% by weight. In yet another embodiment, the PBI-p fiber has about 17% by weight phosphoric acid APU. In yet another embodiment, the PBI-p fiber can have APUs in the lower-upper range, where the lower end of the weight range can be 1,2, 3,4, 5, 6, 7, 8, 9, 10, and 11, and the upper end of the weight range can be: 25. 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11 and 10.

The PBI-P fibers may have any LOI (limiting oxygen index-ASTM D2863). The PBI-p fiber may have an LOI of about 47 +% (. gtoreq.47%). The PBI-p fiber may have an LOI of 50 +% (. gtoreq.50%). The PBI-p fiber may have an LOI of 55 +% (. gtoreq.55%). In one embodiment, the PBI-p fibers may have an LOI of 60 +% (. gtoreq.60%). The PBI-p fibers can have an LOI of 60% or more at 1% or 4% APU phosphoric acid. PBI-p fibers can have an LOI of about 60-75% at 1% or 4% APU phosphoric acid. PBI-p fibers can have an LOI of 60% or more at about 4-25% APU phosphoric acid. The PBI-p fibers may have an LOI of about 60-75% at 4-25% APU phosphoric acid. The PBI-p fibers can have an LOI of about 60-75% in the lower-upper% APU phosphoric acid, where the lower end of the weight range can be 1,2, 3,4, 5, 6, 7, 8, 9, 10, and 11, and the upper limit is selected from 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, and 10. The PBI-p fiber may have an LOI of about 62.3% at about 7% APU phosphoric acid. The PBI-p fiber may have an LOI of about 65.5% at about 12% APU phosphoric acid. The PBI-p fiber may have an LOI of about 63.5% at about 17% APU phosphoric acid. Thus, less than 27 weight percent phosphoric acid-borne, thermo-oxidatively stable fibers can be obtained. This is important because phosphates have a negative impact on the environment. The LOI of the PBI-s fibers is in the range of 41-44%.

In thermogravimetric analysis (TGA), the change in weight of a sample is measured as a function of the temperature increase. A severe weight loss at high temperature usually indicates sample decomposition. The PBI-p fibers can have any thermal decomposition onset temperature in air as determined by thermogravimetric analysis (TGA). TGA tests were performed in air at a heating rate of 20 ℃/min to reach 1000 ℃ for the PBI-s sample and the PBI-p sample (using TA instruments model TGA Q500). The results are shown in FIG. 1. In the test, the initial thermal decomposition temperature of the PBI-s fiber sample is 551 ℃, and under the same test condition, the initial thermal decomposition temperature of the PBI-p fiber sample is more than or equal to 555 ℃. For a TGA test in air at a heating rate of 20 ℃/minute, the PBI-p fibers can have an initial thermal decomposition temperature of about 555-. The PBI-p fibers may have an initial thermal decomposition temperature of 565 ℃ or higher at about 4-25% APU phosphoric acid. The PBI-p fibers may have an initial thermal decomposition temperature of about 565-. The PBI-p fibers may have an initial thermal decomposition temperature in the range of about 565-. The following are the actual test data: the PBI-p fiber has an initial thermal decomposition temperature of about 567 ℃ at about 7% APU phosphoric acid; the PBI-p fibers had an initial thermal decomposition temperature of about 577 ℃ at about 12% APU phosphoric acid; and the PBI-p fiber has an initial thermal decomposition temperature of about 592 ℃ at about 17% APU phosphoric acid.

The PBI-p fiber can have any denier. The PBI-p fiber has a denier of no greater than 6 filament denier (dpf). The PBI-p fiber may have a denier in the range of 0.1 to 5 dpf. In one embodiment, the denier of the fiber is in the range of 1 to 3 dpf.

Polybenzimidazole (PBI) resins are a known class of compounds. See, e.g., US Re26065, US 3,433,772, US4,717,764, and US 7,696,302, each of which is incorporated herein by reference. The Polybenzimidazole (PBI) resin may be any known PBI resin. PBI resin also refers to blends of PBI resin with other polymers, copolymers of PBI, and combinations thereof. The PBI resin component may be the entire (100%) resin component or the major (i.e., at least 50% by weight) component. Typically, the PBI resin may be the melt polymerization product of a tetraamine (e.g., aromatic and heteroaromatic tetraamino compounds) and a second monomer selected from free dicarboxylic acids, alkyl and/or aryl esters of aromatic or heterocyclic dicarboxylic acids, and/or alkyl and/or aryl anhydrides of aromatic or heterocyclic dicarboxylic acids. More details on PBI polymerization can be obtained from U.S. patent nos. reo26065, 4506068, 4814530 and U.S. publication nos. 2007/0151926 and 2014/0357831 (organic aldehyde adduct routes), each of which is incorporated herein by reference. PBI resins and fibers are commercially available from PBI Performance Products, Charlotte, N.C..

Examples of PBI polymers include, but are not limited to: poly-2, 2' - (m-phenylene) -5,5' -dibenzoimidazole, poly-2, 2' - (biphenylene-2 "2'") -5,5' -dibenzoimidazole, poly-2, 2' - (biphenylene-4 "4 '") -5,5' -dibenzoimidazole, poly-2, 2' - (1",1",3 "-trimethylindene (trimethylindanylene)) -3"5 "-p-phenylene-5, 5' -dibenzoimidazole, 2' - (m-phenylene) -5,5' -dibenzoimidazole/2, 2- (1",1",3" -trimethylindene) -5",3" - (p-phenylene) -5,5' -dibenzoimidazole copolymer, poly-2, 2' - (biphenylene-2 "2'") -dibenzoimidazole, poly-2, 2' - (biphenylene) -5,5' -dibenzoimidazole, poly-2, 2' - (trimethylindene) indene) 5", poly-1, 2' - (phenylene, 2,2' - (m-phenylene) -5, 5-dibenzoimidazole/2, 2' -biphenylene-2 ", 2'" -5,5' -dibenzoimidazole copolymer, poly-2, 2' - (furanylidene-2 ",5") -5,5' -dibenzoimidazole, poly-2, 2' - (naphthalene-1 ",6") -5,5' -dibenzoimidazole, poly-2, 2' - (naphthalene-2 ",6") -5,5' -dibenzoimidazole, poly-2, 2' -pentene-5, 5' -dibenzoimidazole, poly-2, 2' -octylene-5, 5' -dibenzoimidazole, poly-2, 2' - (m-phenylene) -diimidazole, benzene, toluene, xylene, Poly-2, 2 '-cyclohexenyl-5, 5' -bisbenzimidazole, poly-2, 2'- (m-phenylene) -5,5' -bis (benzimidazole) ether, poly-2, 2'- (m-phenylene) -5,5' -bis (benzimidazole) sulfide, poly-2, 2'- (m-phenylene) -5,5' -bis (benzimidazole) sulfone, poly-2, 2'- (m-phenylene) -5,5' -bis (benzimidazole) methane, poly-2, 2"- (m-phenylene) -5,5" -bis (benzimidazole) propane-2, and polyethylene-1, 2-2,2"- (m-phenylene) -5,5" -bisbenzimidazole) ethylene-1, 2 wherein the vinyl double bonds are intact in the final polymer. Poly-2, 2'- (m-phenylene) -5,5' -dibenzoimidazole is preferred.

Generally, PBI-p fibers can be prepared by the following method: spinning PBI resin (without any acid treatment, i.e. untreated), the fibers were treated with phosphoric acid.

Spinning may be carried out using any conventional spinning technique. One such technique is solution spinning, which draws a spinning dope (PBI dissolved in a suitable solvent) through a spinneret into filaments, which are subsequently collected after removal of the solvent.

The processing may include the steps of: phosphoric acid is applied to the untreated fibers and, after a suitable residence time, the treated fibers are removed and/or dried. Application of phosphoric acid may be carried out by any conventional method. Conventional methods include, but are not limited to, dipping (e.g., by bath), spraying, brushing, rolling, and the like. In one embodiment, the treatment may be performed in a phosphoric acid bath. In one embodiment, the residence time (time the fiber is immersed in the acid bath) may be in the range of 15 to 360 seconds. In another embodiment, the dwell time may be in the range of 20-180 seconds. In yet another embodiment, the dwell time may be in the range of 20-70 seconds. The bath may be at any temperature. In one embodiment, the bath temperature is in the range of 15-60 ℃. In another embodiment, the bath temperature is in the range of 20-50 ℃. In yet another embodiment, the temperature may be in the range of 25-40 ℃. In yet another embodiment, the temperature may be in the range of 30-40 ℃. The phosphoric acid used in the treatment step may be any concentration of phosphoric acid. In one embodiment, the concentration of phosphoric acid (aqueous) ranges from 10 to 85 weight percent. In another embodiment, the phosphoric acid (aqueous) has a concentration range of 20-60% by weight. In yet another embodiment, the phosphoric acid (aqueous) has a concentration range of 40-60% by weight. In yet another embodiment, the concentration of phosphoric acid (aqueous) is about 50% by weight. The fibers may be under tension while applying the phosphoric acid. In one embodiment, the tension may be in the range of 1.0 to 25.0dN (as measured on a split bundle by a conventional tensiometer). In another embodiment, the tension may be in the range of 2-12 dN. In yet another embodiment, the tension may be in the range of 2-8 dN. In yet another embodiment, the tension may be in the range of 2.5-7.5 dN. The excess acid may be removed and/or dried in any manner. The removal and/or drying may include an optional rinse to remove residual acid.

The PBI-p fibers may be used in any application. Such applications include, but are not limited to: textile applications, mechanical applications and for plastics additives. In textile applications, the fibers (which may be staple or filament fibers) may be spun in combination with other fibers. The yarns may be woven or knitted into a fabric. The fabric may be cut and sewn into a garment. These textile processes are conventional. The PBI-p fibers may also be converted into nonwoven fabrics by any conventional technique. Applications in machinery include, for example, gaskets and seals.

Examples

The extruded polybenzimidazole fiber is washed in hot water to remove the spinning solvent and then spatially stretched in a heated oven to improve its tensile properties. The fiber is then treated by immersion in a bath of 50% by weight aqueous phosphoric acid for 48-52 seconds from entry to exit the apparatus (about 25 seconds of immersion of the fiber in the liquid). The bath temperature was maintained at 35 ℃. However, the device is not suitable for use in a kitchenThe fibers were then extrusion dried and washed with water at room temperature. The washed fibers were then dried in an air non-contact oven at 350 ℃. The dry fibers were then heat treated in an oven charged with nitrogen at 565 c to fix the acid within the polymer structure. Subsequent textile processing produced the phosphorylated fibers as 2 inch cut staple fibers. A cut staple fiber having a denier per filament (dpf) of 1.5, a tenacity of 2.00g/dN, an elongation at break of 10.88% and an acid carry of 17-20% by weight^*。^*Acid carry values were determined by material balance and verified by elemental analysis. Material balance-acid content the weight gain of the fibers was estimated using the material balance. The sample was dewatered and the remaining material was divided by dry PBI from the creel. The balance is then checked by a second balance of acid concentration, wastewater and consumption in the bath. Elemental analysis-acid content, obtained by elemental analysis using inductively coupled plasma emission spectrometry (ICP-OES). The ICP-OES method determines the percentage of a particular element in a sample. In the case of the exemplary fiber, ICP-OES determined the presence of 5.51% phosphorus. However, phosphorus is present as Phosphate (PO) on the exemplary fibers₄) Exist in the form of (1). Phosphorus is present in the phosphate in an amount of about 32%. Thus, a phosphorus content of 5.51% tells us that the phosphate (acid) carry is about 17%.

The data presented in the table below further illustrates the preliminary laboratory phosphoric acid treatment of extruded PBI fibers.

TABLE 1

The present invention may be embodied in other forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.