Nexam – Quotes from a recent polyamide (Nylon) and polyimide patent application

Posted: 9 August, 2015 in Nexam, Published Investment Calls
Tags: , , , , , , , , , ,

Herein, selected quotes are attached from US20140303328, CROSS-LINKER, Nexam Chemical, Publication Date:09.10.2014

For reasons of clarity, bulletpoints, bold text and blue font has occasionally been added to the original patent quote(s) below by CESI.

“Thermoplastic aliphatic polyamides are often referred to as Nylon. Nylons are typically condensation copolymers formed by reacting a diamine and a dicarboxylic acid or ring-opening polymers formed by polymerization of lactames, such as aminocaproic acid. One of the most common variants is nylon 66, also known as PA 66, which name refers to the fact that the diamine (hexamethylene diamine) and the diacid (adipic acid) each donate 6 carbons to the polymer chain.

Nylon was developed as a synthetic replacement for silk and substituted for it in many different products, such as parachutes, after silk became scarce during World War II. Nylon fibers are today used in many applications, including fabrics, carpets, musical strings, and rope. Solid or reinforced nylon (engineering polymer) is used for mechanical parts such as machine parts, gears, containers, tubes, primary and secondary design elements and other low- to medium-stress components previously cast in metal. Engineering-grade nylon is processed by extrusion, casting, and/or injection molding.

In order to improve the mechanical strength, aromatic polyamides, such as aramid, have been developed. Furthermore, aromatic polyamides are less prone to absorb water than aliphatic polyamides. Absorption of water will affect the mechanical strength negatively. However, the processability of aromatic polyamides is inferior to one of aliphatic polyamides. Further, aromatic polyamides are more brittle and less resistance to chemical solvents compared to aliphatic polyamides. It would thus be desirable to be able to use aliphatic polyamides in applications wherein aromatic polyamides typically are used.

  • There have been attempts in the art to improve the mechanical strength of the polyimides, which are related to aromatic polyamides. U.S. Pat. No. 5,493,002 discloses oligoimides endcapped with PEPA (Phenylethynyl phtalic anhydride). The PEPA endcapped oligoimides are cured, i.e. cross-linked, at about 400° C. Similarly, U.S. Pat. No. 5,066,771 discloses use of EPA (ethynyl phtalic anhydride) as an endcapper for oligoimide. The disclosed EPA endcapped oligoimides was cured, i.e. cross-linked, in a step wise manner including heating at 200° C. for 4 hours, at 250° C. for 2 hours, at 290° C. for 1 hour and lastly at 320° C. for 6 hours.
  • Further, there have been attempts in the art to improve the mechanical strength of the aromatic polyamides. EP 1 988 114 discloses wholly aromatic polyetheramides endcapped with PEPA. Wholly aromatic polyamides are thermo stable and withstands the heat required to cure the cross-linkable end-capper PEPA. However, as well known within the art, aliphatic polyamides, such as various types of nylon, are less thermo stable and would degrade at temperatures typically used to cross-link PEPA. Thus, cross-linking of PEPA in polyamides would require catalysis or long term cross-linking at lower temperatures. Accordingly, PEPA has not find use as cross-linkable end-capper for aliphatic polyamides. As an alternative to PEPA, also ethynyl phtalic anhydride (EPA) has been used as cross-linker in polyimides (cf. Hergenrother, P. M., “Acetylene-terminated Imide Oligomers and Polymers Therefrom”, Polymer Preprints, Am. Chem. Soc., Vol. 21 (1), p. 81-83, 1980).
  • Although polyimides comprising EPA may be cross-linked at a lower temperature, i.e. at about 250° C., it suffers from other drawbacks. The exchange of the phenyl ethynyl group to an ethynyl group implies that other reaction pathways than the desired curing mechanism, such as chain extension, are favored. As a consequence, EPA has not found any wide use as a replacement to PEPA as a low temperature curing end-capper. Further, the manufacture of EPA requires protective group chemistry hampering its commercial potential.
  • Neither EPA is suitable as end-capper for polyamides. In addition to the drawback mentioned above, cross-linking of EPA will be initiated at temperature below the normal processing temperature, typically 290 to 310° C., of nylon 66, thus limiting its possible use as a cross-linker for nylon 66 end-capped with EPA would, at least to certain extent, cross-link during processing.
  • Polyamic acids, and their corresponding polyimides, endcapped with PEPA or EPA have been suggested for use in various applications in the art. As an example, JP 2010186134 discloses a photosensitive resin containing an optical base generator (A) and polyamic acid (B), wherein the polyamic acid (B) may have terminal polymerizable group(s). The terminal polymerizable groups are selected from polymerizable groups known in the art, such as anilines or dianhydrides comprising carbon-carbon double or triple bonds. Specifically disclosed examples of polymerizable end-cappers include maleic anhydride, 4-aminocinnamic acid, 4-ethynylaniline, 3a,4,7,7a-tetrahydroisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-4,7-epoxyisobenzofuran-1,3-dione, EPA and PEPA.
  • According to Wollf et al (cf. Synthesis, 2007 (5), 761-765) N-phenylphthalimides with carbon substituents in the 3-position, such as (4-(1-octyn-1-yl)-2-phenyl-1H-Isoindole-1,3(2H)-dione, 4-(1-hexyn-1-yl)-2-phenyl-1H-Isoindole-1,3(2H)-dione, and 4-(3,3-dimethyl-1-butyn-1-yl)-2-phenyl-1H-Isoindole-1,3(2H)-dione, are accessible by Sonogashira coupling reaction of the corresponding bromo derivatives. 3-alkyl substituted N-phenylphthalimides may be used as synthetic intermediates for the production of pre-organized hydrogen bonding donors for the synthesis of supramolecular affinity molecules.
  • U.S. Pat. No. 6,344,523 addresses the disadvantageous of the too high curing temperature of PEPA discussed above and discloses that use of sulfur or organic sulfur derivatives as curing promoters may lower the curing temperature of phenylethynyl terminated imide oligomers. However, the introduction of such promotors suffers from other disadvantages. In particular the curing results in chain extension rather than cross-linking as two ethynyl groups react along with one sulfur radical ultimately forming a thiophene structure.

Thus, there is need within the art for an alternative cross-linking monomer, overcoming the above-mentioned deficiencies, to be used as cross-linking monomer for aliphatic polyamides, such as PA66. 

CESI: Now, in this patent, Nexam has revealed that polyamides comprising a residue endcapped with two new formulas (I and II, see patent for full structural formula) may be cross-linked at a slightly lower temperature than polyamides comprising a residue of PEPA, i.e. at about 310° C.

“This temperature is high enough to allow normal processing of an aliphatic oligo- or polyamide, such as PA66, comprising a residue of a compound according to formula (I) or (II), without initiating curing, i.e. cross-linking, to any substantial extent. However, an aliphatic oligo- or polyamide comprising a residue of a compound according to formula (I) or (II) may, in contrast to an oligo- or polyamide comprising a residue of PEPA, be cured, i.e. cross-linked, without any significant thermo degradation of the oligo- or polyamide.

Thus, an embodiment of the present invention relates to a compound according to formula (I) or (II) as disclosed herein

Compounds according to formula (I) or (II) are suitable as end-cappers for oligomers and polymers comprising functional group(s) which may react with carboxylic anhydrides, such as compounds according to formula (II), or carboxylic acids or derivatives thereof, such as compounds according to formula (I). Such functional group(s) may be selected from group consisting of primary amino groups, hydroxy groups and epoxy groups.

[…]

Common examples of oligo- and polyamides, which may be end-capped or chain elongated with compounds according to formula (I) or (II), comprises Nylon 6, 66, 46, 69, 610, 612, 11, 12, 6T, 6I, 6DT, or mixtures thereof.

[…]

Further, the oligo- and polyamide, which may be end-capped or chain elongated with compounds according to formula (I) or (II) may be a semiaromatic oligo- or polyamide, such as PA6I.

[…]

As known to the skilled artisan, polyamides are hard to dissolve. Thus, although possible, it may be disadvantageous to introduce a compound according to formula (I) or (II) via a chemical reaction in solution. Further, modification of polymers in solution is general avoided as far as possible as it introduces additional steps into a production process dissolution and evaporation.

One option to introduce a compound according to formula (I) or (II) into oligo- and polyamide is to have them present as an additional constituent during the polymerization. However, although compounds according to formula (I) or (II) may act as chain extenders, the degree of polymerization would anyhow most likely be negatively affected. Further, the very long polymerization reaction times tend to decrease the yield of the cross-linker incorporated due to degradation.

However, it has unexpectedly been found that compounds according to formula (I) or (II), and especially compounds according to formula (II), wherein “X” is “O” (oxygen), may be introduced into polyamides by melt modification, i.e. be mixing compounds according to formula (I) or (II) into melted polyamides. Although, melt modification of polyamide to blend fillers, pigments, external flame retardant, stabilizers, plasticizer into the polyamide is known within the art, it is unexpected that compounds according to formula (I) or (II) may be effectively introduced into polyamides without degrading the polymer or the compound it self.

[…]

Furthermore, not only oligo- or polyamides may be end-capped via melt mixing with a cross-linkable aromatic carboxylic acid anhydride comprising a carbon-carbon triple bond. Also other polymers, comprising functional group(s) which may react with carboxylic anhydrides, which polymers may be melted at a lower temperature than the temperature at which cross-linking is initiated, may be end-capped via melt mixing. Such functional group(s) may be selected from group consisting of primary amino groups, hydroxy groups and epoxy groups. As an example, also epoxides and polyesters may be end-capped via melt mixing.

Common examples of oligo- and polyesters, which may end-capped or chain extended with compounds according to formula (I) or (II), comprises poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), poly(propylene terephthalate) (PPT) and poly(butylene terephthalate) (PBT).

[…]

As well known in the art, asymmetric aromatic diamines and dianhydrides may be used to prepare polyimides with a bent and rotationally hindered structure resulting in high Tg but also in improved processability and high melt fluidity along with and solubility of the resin in organic solvent. Symmetric aromatic dianhydrides as well asymmetric aromatic dianhydrides are equally possible.”

[CESI believes the Jayhawk Dianhydrides (such as a-BTDA) by Evonik could be defined as bent and rotationally hindered structures. These structures was discussed in the joint Nexam Evonik webinar.

More information from Evonik is available here:

http://composites.evonik.com/product/composites/en/products-services/matrix-systems/thermosets/Specialty%20anhydrides/Pages/default.aspx 

Ok, that was just an observation. Now, back to the main Nexam patent quote:]

“Another embodiment relates to an article comprising an oligomer or polymer comprising a residue according to formula (III) or (IV). Optionally, the oligomer or the polymer in the article has been cross-linked by heating it. Typically examples of articles comprising such oligomers or polymers include specialty organic fibers, such as meta- and para-Aramids, Polybenzimidazole (PBI), Polyethylene, Polyimide, Polyamideimide (PAI), Liquid Crystal Polymer Fibers.

Another embodiment relates to an article comprising an oligomer or polymer comprising a residue according to formula (III) or (IV). Optionally, the oligomer or the polymer in the article has been cross-linked by heating it.

Typically examples of articles comprising an oligo- or polyimide comprising a residue according to formula (III) or (IV), include flexible films for electronics, wire isolation, wire coatings, wire enamels, ink, and load-bearing structural components.

Typically examples of articles comprising an oligo- or polyamide comprising a residue according to formula (III) or (IV), include synthetic fibers, automotive parts, industrial machinery, electronics, films, wires, cables, tubing, pipes and stock shapes.

Typically examples of articles comprising a oligo- or polyester comprising a residue according to formula (III) or (IV), include synthetic fibers and containers, such bottles for beverages.

Similar to PEPA and EPA, also compounds according to formula (I) or (II), as well as compounds comprising a residue of such a compound, may cross-linked by heating them. Without being bound to any theory, it is believed that, upon heating of mixtures of compounds comprising ethynyl moieties, these moieties will eventually start to react. Reaction of two ethynyl moieties of separate molecules will provide a chain extended product, while reaction of three ethynyl moieties of separate molecules is thought to provide a benzene moiety with three “arms”. Subsequently, two or three ethynyl moieties present on such “arms” may react to form a cross-linked product. “

[CESI: This was the graphical visualization produced by CESI and subsequently used in the original Nexam blog post, click picture for enlargement and a higher quality visualization:

CYCLOTRIpng240SUN final

In this graphical visualization in total 6 arms of a benzene ring were depicted of which 3 arms corresponded to polymer arms. This should also be correct and CESI believes Nexam´s definition of arms in fact is corresponding to the (two or) three polymer arms, not the total amount of arms (the additional three “passive” arms carrying the small melting point regulator backpack)]

Ok, back to the patent quote:]

“Chain extension, but especially cross-linking, will improve the properties of an oligo- or polymer comprising ethynyl moieties, as has been shown in the art. Heat initiated chain extension, but especially cross-linking, of oligo- or polymers comprising ethynyl moieties is often referred to as curing.

The curing of compounds, such as oligo- or polyamide, comprising a residue according to formula (III) or (IV), and compositions or articles comprising an oligo- or polyamide comprising a residue according to formula (III) or (IV), may be accomplished by heating.

Such heating may be performed in an isothermal staging process. As an example, such an isothermal staging process may start by heating the material to be cured to 250° C. to 350° C., such as at about 280° C., for some time, typically 1 to 2 hours. However, also less time, such as less than 1 hour, or less than 30 minutes, may be used. Further, also longer times, such as up to 10 hours may be used. Subsequently, the temperature may be increased in steps. Each step may correspond to an increase of the temperature of 5° C. to 25° C. Further, each step may have a duration of 30 minutes to 10 hours, such as 1 to 2 hours. The last step may be curing at a temperature of 300 to 350° C., such as at about 350° C.

While temperatures exceeding 350° C. should be avoided for longer periods of time, curing at temperatures may be tolerated for short periods of time, such as less than 1 minute. Especially, polymer films may be cured at temperatures exceeding 350° C. for short periods of time.

[CESI: Finally, below is described the preparation of a selection of important polymers. This final quote was also obtained from the Nexam patent application US20140303328]

“The dissertation thesis “Synthesis and characterization of thermosetting polyimide oligomers for microelectronics packaging” by Debra Lynn Dunson, Virginia Polytechnic Institute and State University, from 2000, provides information relating to the preparation of PEPA end-capped oligo- and polyimides. Similar procedures may be employed to prepare oligo- and polyimides comprising residues of compounds according to formula (I) or (II) as disclosed herein. Thus, the dissertation thesis “Synthesis and characterization of thermosetting polyimide oligomers for microelectronics packaging” by Debra Lynn Dunson, Virginia Polytechnic Institute and State University,from 2000 is incorporated herein by reference. As well known to the skilled artisan, various polyamides and polyesters may be obtained as disclosed herein below.

  • In preparing Nylon 66, Adipic acid (derived from cyclohexane) and hexa-methylene-diamine (most commonly derived from butadiene or acrylonitrile) are prereacted to form nylon salt that is particularly well suited to purification. Subsequently, the purified nylon salt is heated and, as water is removed, the polycondensation proceeds, current production units operate both continuously and by batch procedures.
  • In preparing Nylon 6, Caprolactam (derived from cyclohexane or phenol) is reacted in the molten state with controlled amounts of water to obtain intermediate epsilon-aminocaproic acid, which readily condenses to the corresponding polyamide 6 as water is removed under controlled conditions of temperature and pressure.
  • Nylon 46 resin is produced by reacting 1,4-diaminobutane with adipic acid. 1,4-Diaminobutane is derived by reacting acrylonitrile with hydrogen cyanide and subsequent reduction of the intermediate.
  • Nylon 69 resins are produced (via an intermediate) from hexamethylene diamine and azelaic acid. Azelaic acid is typically derived from tallow (via oleic acid).
  • Nylon 610 resins are produced (via an intermediate) from hexamethylene diamine and sebacic acid. Sebacic acid is usually derived from castor oil.
  • Nylon 612 resins are produced (via an intermediate) from hexa-methylene-diamine and dodecanedioic acid (DDDA), which is most often derived (via cyclododecane) from butadiene.
    Copolymer 6/12 resins are prepared from DDDA, caprolactam, hexa methylene diamine, adipic acid and/or other materials.
  • Nylon 11 resins are obtained from the self-condensation of 11-amino-undecanoic acid, which is typically derived from castor oil.
  • Nylon 12 resins are obtained from laurolactam in much the same manner in which nylon 6 is obtained from caprolactam. Laurolactam is usually derived (via cyclododecane) from butadiene.
  • PPA (polyphthalamide) is a copolymer made from terephthalic, isophthalic, and adipic acids and hexa-methylene-diamine.

[…]

  • Polybutylene terephthalate (PBT) resin is produced by the polycondensation of approximately equal molar proportions of 1,4-butanediol and dimethyl terephthalate (DMT). The first step in the reaction is transesterification, in which 1,4-butanediol replaces the methyl groups in the DMT molecule to form bis-(4-hydroxybutyl)-terephthalate (BHBT) and methyl alcohol, as shown below. The liberated methyl alcohol is removed from the reaction system to drive the exchange to near completion. PBT is produced by polycondensation of BHBT usually in the presence of a catalyst (commonly based on titanium) under reduced pressure at 240-260° C. As polycondensation occurs, 1,4-butanediol is produced and is removed from the polycondensation reaction as a vapor.
  • Virgin Polyethylene terephthalate (PET) polymer is produced by polycondensation of ethylene glycol with either dimethyl terephthalate (DMT) or terephthalic acid (TPA) via intermediate bis-(2-hydroxyethyl)-terephthalate (BHET).

Source link: The full patent is available here

Best regards, C.E.S.I.

The author, Cutting Edge Science Invest, is a Nexam Chemical share holder. Cutting Edge Science Invest can not guarantee, or take into  accountability, the content of truth and accuracy of the information in this article/post.Thus, Cutting Edge Science Invest requires that a possible reader gather complimentary information if any type of investment in the company described above is considered. Cutting Edge Science Invest provides personally biased information and at best also “general information and opinions”. The article/post does not contain professional investment advice. 

Comments
  1. Sten Stjernswärd says:

    Var stod vi utan ditt kemi kunnande! ? Alla vi andra kan tycka en massa saker, men du förefaller på forumet, att vara den enda som har har de rätta kunskaper på detta området.
    Hoppas Nexam nu blir den framgångssaga som vi alla hoppats på. Tiden verkar vara mogen för det. Det blir en spännande höst.

  2. Jens-Olafur Edgren says:

    hehe, utförligt och bra som vanligt! Jensa

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