Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/42—Polyamides containing atoms other than carbon, hydrogen, oxygen, and nitrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
  • C08J2377/06—Polyamides derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids

Definitions

• the invention relates to a flame-retardant polyamide as a condensation product of dicarboxylic acids with diamines and also a flame-retardant phosphorus compound, to a process for producing this flame-retardant polyamide, and to its advantageous use for producing shaped articles, more especially filament yarns.
• Polymers based on commercial polyamides without appropriate modifying additives as needed to achieve nonflammability are assigned to fire protection class “B” (DIN 4102—BS 5852—M1—UL94). Only by means of additional treatment is it possible to attain class “B1” (materials that are not easily flammable).
• This treatment may involve incorporation of a suitable flame retardancy component into the polyamide chain or polymer matrix, or alternatively the treating of polyamide yarns or polyamide textiles with suitable flame retardants.
• the degree to which such materials may be rendered not easily flammable is dependent on the additions and on the method utilized to achieve this condition, and is operated individually according to the applications and the statutory impositions.
• the methods that are nowadays typically utilized in order to render a material flame-retardant may be subdivided into physical and chemical methods.
• physical polymer modification it is usual to produce two-phase systems, in one case by incorporating flame-retardant additives—of either mineral or organic nature—into the polymer.
• flame-retardant additives of either mineral or organic nature—into the polymer.
• the surface of the polymeric material is coated or treated, with flame-retardant additions being applied that are anchored physically, but may also be attached reactively, this amounting in itself to chemical modification.
• modification in the polymer chain the addition of a comonomer in the polymerization step that is active as a flame retardant, modification via polymer-analogous reactions on the main chain in the form of grafting and/or branching by the FR component on the polymer main chain, and also modification by subsequent crosslinking of the polymer chains with one another, to form, for example, a radically initiated polymer network, possibly producing an “unmeltable” polymer.
• halogen-containing compounds suitable for this purpose are multiply substituted unsaturated, cyclic aliphatics and heteroaliphatics, and also fused aromatic systems or those which are bridged via heteroatoms (U.S. Pat. No. 3,810,861 A, DE 2604275 A1, EP 79177 A1). These compounds are frequently also used in combination with metal oxides/hydroxides, carbonates, acetates, phosphates, borates, etc., since these compounds have a synergistic effect on flame retardancy (DE 2114235 A, AT 355307 B, DE 2114235 A, U.S. Pat. No. 3,810,861 A). Examples of this are found in a variety of patents, usually older ones, since in more recent times these systems have come under considerable pressure on account of the toxic and ecotoxic products they generate in service.
• phosphorus-containing prepolymers with addition of resin/curing agent systems. These systems allow reduction to be achieved in the required mass fraction of the phosphorus component in the context of the flame retardancy effect, this being beneficial for the mechanical properties of the material (DE 102006060339 A1, DE 102005015605 A1). Furthermore, various cyclic phosphinic acid derivatives based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) are described which as well as use preferably in thermosets are said to be also used in thermoplastic polyesters and polyamides for fibre manufacture (DE 2646218 A1, EP 1710264 A2, EP 1710264 B1).
• DOPO 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide
• the aim of the invention is that of proposing improved flame-retardant polyamides, an especially suitable process for producing them, and also advantageous uses of these flame-retardant polyamides.
• the invention achieves this object by means of a flame-retardant polyamide FR as condensation product of dicarboxylic acids with diamines and also a flame-retardant phosphorus compound, which is characterized in that the flame-retardant polyamide FR contains in its main chain not only the amide structural units of the formula (I)
• R 1 being hydrogen or an organic group, and in which individual phosphinamide structural units within the main chain may be different, and in that the polyamide FR attains a relative viscosity, measured as a 1% strength solution in 96% strength sulfuric acid at 25° C., of at least 2.0 (according to DIN 51562).
• the aforesaid group R 1 is a linear, cyclic or branched C 1 -C 6 alkyl group, more especially a C 1 -C 3 alkyl group, an aryl group, more especially having up to three fused or unfused rings, more especially in the form of a phenyl, benzyl, naphthyl, phenanthryl, mesityl or tolyl group, an alkylaryl group, more especially a triphenylmethyl group, and/or an arylalkyl group, more especially an i-propylphenyl, t-butylphenyl or nonylphenyl group.
• the C 1 -C 3 alkyl group here is preferably a methyl, ethyl and/or 2-propyl group.
• the desirable improvement in flame retardancy is achieved through the phosphinamide structural units of the formula (II) identified that are introduced into the polyamide in accordance with the process described hereinafter.
• the flame-retardant polyamide FR by virtue of the phosphinamide structural units, based on the pure flame-retardant polyamide FR, contains at least 0.01 and/or not more than 10.0 wt % of phosphorus, it being preferred for the polyamide FR to contain 0.01 to 8 wt %, more especially 0.01 to 4.0 wt %, of phosphorus, an especially preferred range being that from 0.01 to 1.5 wt % of phosphorus.
• the following pairs of values for the phosphorus content may be identified as being advantageous: 0.1 to 10 wt %, preferably 0.5 to 6 wt %, and more especially 0.1 to 1.5 wt % of phosphorus.
• improved flame retardancy in the target polyamide FR is achieved to a particular extent without detrimental effect on the otherwise desirable qualities of the polyamide FR. It has proven advantageous here for the flame-retardant polyamide of the invention to have a nonflammability which conforms to the mandates of the UL94 V.0 protocol.
• the invention opens up further possibilities for modification to the flame-retardant polyamide FR, including, for example, the inclusion of property-improving additives, more especially of UV stabilizers, heat stabilizers and/or matting agents. There is in fact no quantitative restriction on these additives. Nevertheless, it is generally judicious if the flame-retardant polyamide FR contains about 0.01 to 1.0 wt %, more especially 0.5 to 0.7 wt %, of additive.
• the aforementioned relative viscosity is at least 2.4. Particular advantageous results are achieved when the relative viscosity (measured according to DIN 51562) attains at least 2.4 and/or not more than 4.0.
• the aforementioned relative viscosity of the flame-retardant polyamide FR of the invention is a parameter which is important in relation to further processing, especially in the context of an extrusion process, such as a blow-moulding, injection-moulding or melt-spinning process.
• an extrusion process such as a blow-moulding, injection-moulding or melt-spinning process.
• a suitable molecular weight report would refer to the relative viscosity, to be determined initially in a simple way.
• the relative viscosity determined is an especially suitable parameter for the skilled person in order for the invention to be practised in the desirable way with achievement of the stated aim.
• the invention is not confined to specific diamines and dicarboxylic acids as base materials for producing the target flame-retardant polyamide. Nevertheless, the following combinations may be stated as being especially advantageous:
• One especially advantageous development of the technical concept of the invention is a flame-retardant polyamide which is present in a mixture with a further polyamide in the form of a non-flame-retardant polyamide, more especially with polyamide 6 (polycaprolactam), the phosphorus content of the mixture being adjusted by the flame-retardant polyamide FR included to at least 0.01 wt % and/or not more than 10.0 wt %, more especially not more than 8.0 wt %, with the phosphorus content from 0.01 to 4.0 wt %, more especially 0.01 to 1.5 wt %, being especially advantageous.
• the following may also be stated as preferred framework conditions: 0.1 to 10.0 wt %, more especially 0.5 to 6.0 wt %.
• a flame-retardant or incombustible polyamide FR can be obtained by melting the flame-retardant polyamide in the mixture identified and, especially, extruding it to form a multifilament yarn.
• a polyamide 6 polycaprolactam
• the phosphorus content of the multifilament yarn is reduced further and can be taken down to a level where the limit of incombustibility is obtained.
• the preferred phosphorus content of a polymer mixture of this kind, as shown above, is from 0.01 to 1.5 wt %.
• the relative viscosity is especially advantageous for the relative viscosity to be adjusted accordingly. It is judicious for the mixture of flame-retardant polyamide FR and the customary or standard, non flame-retardant polyamide to attain a relative viscosity, measured as a 1% strength solution in 96% strength sulfuric acid at 25° C., of at least 2.0, more especially of at least 2.4 and/or not more than 4.0 (measured according to DIN 51562).
• the phosphorus content of the mixture here is, especially, at least 0.05%.
• the relative viscosity is generally not more than 3.5, more especially not more than 2.9. In general it is less than 2.7.
• the flame-retardant polyamide FR of the invention can be produced especially advantageously by a process in which in a polyamide synthesis one or more diamines are subjected to polycondensation with one or more dicarboxylic acids under a pressure of at least 16 bar, more especially a pressure from 20.0 bar to 25 bar, and at elevated temperature, more especially a temperature of less than 295° C., more especially from 230° C.
• R 2 and R 3 independently of one another, are a linear, cyclic or branched C 1 -C 6 alkyl group, more especially a C 1 -C 3 alkyl group, an aryl group, more especially having up to three fused or unfused rings,
• the pressure is lowered to less than 100 mbar, preferably to 1 to 100 mbar, more especially 1 to 50 mbar. It is especially advantageous if the pressure is lowered to 1 to 10 mbar.
• the proportion of the reactants in the form of the diamines, dicarboxylic acids, diphosphinic acids, and the carboxy-phosphinic acids is adjusted such that the phosphorus content of the flame-retardant polyamide process product obtained, based on the polyamide FR, is at least 0.01 wt % and/or not more than 10.0 wt %; further advantageous framework conditions are referred to above.
• a further advantageous embodiment of the process of the invention is that the flame-retardant polyamides produced from an AH salt of the diphosphinic acid of the formula (III) and/or of the carboxy-phosphinic acid of the formula (IV) are present without blending or in a blend with a further, non-phosphorus-containing, non-flame-retardant polyamide and are passed on for further use.
• the point of departure of the invention is the finding that in order to produce the flame-retardant polyamide FR of the invention, the incorporation of diphosphinic acid and/or of a carboxy-phosphinic acid by condensation in the main chain of the polyamide is employed, especially and by way of example in connection with the synthesis of PA6.6 from adipic acid and hexamethylenediamine, with an AH salt of the phosphorus-containing acids being provided in accordance with the AH salt prepared in the synthesis of PA6.6 from adipic acid and hexamethylenediamine.
• an intrinsically incombustible or flame-retardant copolyamide is produced wherein the respective dicarboxylic acid, more especially adipic acid, is replaced in part by a diphosphinic acid and/or by a mixed carboxy-phosphinic acid.
• these reactants are incorporated statistically into the polyamide chain, without substantial influence on the polymerization reaction or on the physical properties of the polyamide.
• the polycondensation takes place preferably with addition of water at a temperature as specified above, judiciously within from three to four hours, under a pressure as specified above. This is followed by depressurization through a needle valve and by the discharge of the steam, with the torque on the stirrer climbing from 0.5 Nm to 8-9 Nm within 45 minutes.
• the polymer melt is then discharged, pelletized, washed, and dried in a fine vacuum. In this form, processing takes place by a melt spinning process, generating a multifilament yarn which cannot be induced to burn even on permanent exposure to a flame.
• the general rule is that it is advantageous for the proportions of the reactants in the form of the diamines, dicarboxylic acids, diphosphinic acids, and carboxy-phosphinic acids to be adjusted such that the phosphorus content of the resulting polyamide FR complies with the advantageous framework conditions stated above.
• a mixed carboxy-phosphinic acid to make use, for example, of 3-hydroxyphenylphosphinylpropionic acid (3-HPP) in a concentration for which the amount used results in a phosphorus content of the completed copolyamide that, as already identified above, is situated especially in the order of magnitude of around 1 wt %.
• 3-hydroxyphenylphosphinylpropionic acid 3-hydroxyphenylphosphinylpropionic acid
• the flame-retardant polyamides of the invention and the products produced by the process described exhibit advantageous properties when they are further processed to give shaped articles, more especially to give films, components and monofilaments or filament yarns. This takes place judiciously as part of a melting process, more especially with a blow-moulding process and/or an injection-moulding process for the production of films and/or components, and also a filament spinning process for producing monofilament and/or multifilament yarns and also staple fibre yarns.
• the yarns In the case of production by a filament spinning process, it is judicious for the yarns to be produced in a melt spinning/winding unit and to be taken off under a spinneret at a speed from 500 to 5000 m/min, more especially from 1500 to 4500 m/min, and wound to form reels or cut to form stacks and pressed to form bales. It is especially advantageous here if the production of the yarns is controlled, by variation of the polymer throughput in the upstream extruder and of the winding speed, in such a way that the linear filament density of the resulting filament yarns is adjusted to 1 to 20 dtex.
• the linear filament density is to 20 dtex in relation to subsequent use for producing carpets, 1 to 5 dtex for producing apparel items, and less than about 1 dtex for producing textiles based on microfibres. It is therefore found that the filaments or filament yarns produced and also staple fibres obtained from them can be employed advantageously for producing sheetlike textile structures, more especially formed-loop knits, woven fabrics, nonwoven webs, and drawn-loop knits.
• This adjustment to the linear filament density takes place preferably such that in the subsequent application of the filament yarn as technical yarn or as yarn for the home textiles segment, the linear filament density is from about 10 to 20 dtex, or from about 1 to 5 dtex for application in the apparel sector, and less than about 1 dtex, more especially below 0.8 dtex, in the case of textiles based on microfibres; specific reference to this has already been made.
• the implementation of the process of the invention or the actualization of the invention in the form of the flame-retardant polyamide opens up innovative possibilities for producing intrinsically flame-retardant polyamides, starting from phosphorus-containing mixed AH salts of the type designated, without any need for fundamental change in the implementation of the polymer synthesis or polycondensation or in the production of the extruded products, it being necessary nevertheless to take account of the deviations relevant to the invention, as detailed above.
• the invention displays a significant advantage here: with the process of the invention, the required molecular weight of the flame-retardant polyamide FR can be obtained directly at the end of the polymerization reaction, by lowering the pressure within the reactor under atmospheric pressure, it being especially advantageous that the pressure is lowered to 1 to 100 mbar, preferably 1 to 50 mbar, more especially to 1 to 10 mbar. This makes the process of the invention very advantageous relative to the outlined prior art with a downstream solid-phase polycondensation procedure.
• HPP 3-Hydroxyphenylphosphinlypropionic acid
• HDMA 1,6-diaminohexane
• a steel autoclave with a pressure stability rating to 25 bar is charged with the modified AH salt according to Example 1 and with a customary, commercial AH salt formed from 1,6-diaminohexane and adipic acid in a weight ratio of 1:9, and also with the approximately four-times molar amount of water, and this initial charge is placed under nitrogen.
• the reactor is then sealed and its contents are heated to 223° C. over the course of three hours. During this time, the pressure in the reactor rises to 20.5 bar. This is followed by slow depressurization over the course of 45 minutes, with further heating to 276° C. at the same time.
• the water which was liberated during the reaction is removed from the reaction product via an ascending condenser and a descending condenser.
• the torque of the stirrer undergoes a sharp increase and reaches a constant value which signals the time of the discharge of the polymer from the reactor.
• Discharge of the melt from the reactor is accomplished by application of nitrogen pressure in the form of a strand, which solidifies directly beneath the discharge valve in an ice bath and, after removal from the ice bath, is processed directly in a pelletizer to form extruded pellets.
• the pellets thus produced are subsequently boiled with water and dried for further processing to a residual moisture content of 250 ppm at 100° C. under reduced pressure.
• the phosphorus content of the completed polymer attains a maximum level of about 1%.
• the melting point of the polymer is 252° C. and the relative viscosity of the 1% strength polymer solution, measured in 96% strength sulfuric acid at 25.00° C., is 2.48.
• the modified polyamide produced above is mixed in a weight ratio of 1:9 with commercial PA6 pellets (e.g.: Ultramid BS24N03 from BASF) and is processed in the form of a dry blend. This is done using a melt spinning unit which comprises a single-screw extruder, a melt spinning pump and spinneret pack, and also a high-speed winder, with which the filament yarn produced is wound up onto reels at a take-off speed of 4000 m/min.
• the filament yarn consists of 24 individual filaments and possesses a linear density of about 63 dtex.
• the mechanical yarn data determined in the tensile test are 38.4 cN/tex for the tensile strength, 54% for the elongation at break, and 283.4 cN/tex for the initial modulus.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Polyamides (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Artificial Filaments (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Related Parent Applications (2)

Related Child Applications (1)

Publications (1)

Family

ID=50424227

Family Applications (2)

Family Applications After (1)

Country Status (11)

Families Citing this family (7)

Citations (1)

Family Cites Families (28)

• 2014
  • 2014-03-27 CN CN201480024353.3A patent/CN105164181B/zh not_active Expired - Fee Related
  • 2014-03-27 JP JP2016504676A patent/JP6401238B2/ja not_active Expired - Fee Related
  • 2014-03-27 ES ES14714660.9T patent/ES2636801T3/es active Active
  • 2014-03-27 CA CA2908191A patent/CA2908191A1/en not_active Abandoned
  • 2014-03-27 PT PT147146609T patent/PT2978793T/pt unknown
  • 2014-03-27 DK DK14714660.9T patent/DK2978793T3/en active
  • 2014-03-27 US US14/780,897 patent/US20160039975A1/en not_active Abandoned
  • 2014-03-27 DE DE102014004454.8A patent/DE102014004454A1/de not_active Withdrawn
  • 2014-03-27 SI SI201430336T patent/SI2978793T1/sl unknown
  • 2014-03-27 EP EP14714660.9A patent/EP2978793B1/de active Active
  • 2014-03-27 WO PCT/EP2014/056159 patent/WO2014154805A1/de active Application Filing
• 2017
  • 2017-10-23 US US15/790,323 patent/US10118990B2/en not_active Expired - Fee Related

Patent Citations (1)

Also Published As

Similar Documents

Legal Events