Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-11-27
2004-07-27
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S101000, C524S126000, C524S127000, C524S128000, C524S129000, C524S130000, C524S131000, C524S132000, C524S133000, C524S135000, C524S136000, C524S140000, C524S141000, C524S145000, C524S147000, C524S151000, C524S152000, C524S153000, C523S451000, C523S461000
Reexamination Certificate
active
06767941
ABSTRACT:
The invention relates to a halogen-free, flame-retardant composition comprising at least an organic phosphorus compound (A) and melamine or a compound derived from melamine (B), or a melamine-phosphorus compound (AB).
Such a composition is known from WO 99/02606, which describes polybutylene terephthalate (PBT) compositions that contain a halogen-free, flame-retardant composition consisting of resorcinol-bis-(diphenylphosphate) (RDP) or a trimethylolpropanol ester of methylphosphonic acid and melamine cyanurate or melam. Said publication also describes a polyamide-6 composition that contains a halogen-free, flame-retardant composition consisting of the trimethylolpropanol ester of methylphosphonic acid and melamine cyanurate or melam.
The drawback of the composition according to the state of the art is that the polycondensate compositions in which the flame-retardant composition can be used, in particular polyamide and polyester compositions containing glass fibres, have flame-retardant properties that do not yet meet the highest requirements. In particular the after-burning time is generally too long, in many cases even longer than 30 seconds, as a result of which no V-O classification according to the UL-94 test of the Underwriter Laboratories can be obtained. It is hence desirable to shorten the after-burning time, i.e. the time for which a composition burns after the removal of the flame. The polycondensate compositions in which the flame-retardant composition according to the invention is used can consequently for example obtain a better UL-94 classification, or a polycondensate composition with flame-retardant properties, similar to the ones disclosed in WO 99/02606, can be obtained using a smaller amount of flame-retardant composition.
The inventors have now surprisingly found that the after-burning time of a polycondensate composition that contains the flame-retardant components(A)+(B) or (AB) according to the state of the art can be shortened if the flame-retardant composition also contains a polymer (C) comprising at least one type of olefine having 2-12 carbon atoms and 0.1-30 wt. % (relative to the weight of the polymer) of at least one comonomer containing acid, acid anhydride or epoxy groups.
Another part of the invention is a polycondensate composition containing the flame-retardant composition according to the invention. An additional advantage of the polycondensate composition according to the invention is that the mechanical properties of the polycondensate composition according to the invention are not or not significantly lower than those of the polycondensate compositions according to the state of the art that do not contain component (C).
As component (C), the flame-retardant composition according to the invention contains a polymer comprising at least one olefine having 2-12 carbon atoms and 0.1-30 wt. % (relative to the weight of the polymer) of at least one comonomer containing acid, acid hydride or epoxy groups. Suitable polymers are for example ethylene, propylene or ethylene-propylene copolymers containing 0.1-30 wt. % (relative to the weight of the copolymer) of a comonomer containing acid, acid anhydride or epoxy groups. Said polymers may also contain comonomers that do not contain the aforementioned groups, for example acrylic esters or vinyl acetate. Preferably the polymer contains 0.5-12 wt. % (relative to the weight of the polymer) of a comonomer containing acid, acid anhydride or epoxy groups. Examples of such comonomers are acrylic acid, methacrylic acid, maleic anhydride, glycidyl acrylate and glycidyl methacrylate.
In a preferred embodiment the polymer is a polymer having a general chemical composition based on E, X and Y, with E standing for an ethylene radical, X standing for a radical formed from the compound
where R
1
=alkyl radical having 1-8 carbon atoms R
2
=H, CH
3
or C
2
H
5
and Y a radical formed from glycidyl (alkyl)acrylate; for example glycidyl (meth)acrylate. Preferably the polymer based on E, X and Y contains 40-90 wt. % E, 1-40 wt. % X and 0.5-20 wt. % Y, the sum of the amounts being equal to 100 wt. %.
The use of polymer having a chemical composition based on E, X and Y in concentrations of 1-20 wt. % in halogen-containing flame-retardant polyester compositions is known from EP-B1-174,343 (DuPont) for increasing the ductility of said polyester compositions, especially at low temperatures.
The polymer component(C) is commercially available, for example as an ethylene/acrylic ester/glycidyl methacrylate terpolymer (Lotader® AX, Elf Atochem), ethylene/glycidyl methacrylate (Bondfast®, E with a mol. weight M
n
=120,000, Sumitomo), ethylene/methacrylic acid (Nucrel®, Dupont), propylene/maleic anhydride (Himont), propylene/acrylic acid (Polybond®, BP Chemical) and ethylene/alfa-olefine copolymer modified with maleic anhydride (Tafmer®, Mitsui). Preferably, an ethylene/acrylic ester/glycidyl methacrylate terpolymer is chosen, more preferably an ethylene/methylmethacrylic ester/glycidyl methacrylate terpolymer (Lotader® AX 8900, Elf Atochem, with a molar weight (M
n
) of approximately 90,000).
In polyester compositions good results were obtained with an ethylene/methylmethacrylic ester/glycidyl methacrylate terpolymer (Lotader® AX 8900). In polyamide compositions good results were obtained with an ethylene-propylene copolymer, modified with 0.5 wt. % maleic anhydride (Tafmer®, Mitsui).
Suitable organic phosphorus compounds (component A) are for example organic phosphates, phosphites, phosphonates, phosphinates and phosphine oxides. Preferably, phosphates, phosphonates or phosphinates are chosen. Examples of such phosphorus compounds are described in for example the “Encyclopedia of Chemical Technology”, Vol. 10, p. 396 ff. (1980). Many are commercially available, for example resorcinol-bis(diphenylphosphate) oligomer, under the trade name Fyrolflex® RDP from AKZO-Nobel, NL; cresyl-diphenylphosphate (CDP) under the trade name Kronitex® CDP from FMC, UK; trimethylolpropanol ester of methylphosphonic acid, under the trade name Antiblaze® 1045 from Albright & Wilson, USA; polypentaerythritol phosphonate under the trade name Cyagard® RF 1041 from American Cyanamid, USA; Hostaflam® OP 910, a mixture of cyclic di- and triphosphonates from Clariant, Germany.
Preferably, a phosphorus compound with a low volatility is chosen as component (A).
Suitable for use as the compound derived from melamine (component B) are for example melamine derivatives, melamine condensation products or mixtures thereof. In the context of this application a “melamine derivative” is understood to be melamine with one or more amine groups having been substituted with one or more alkyl, aryl, aralkyl or cycloalkyl groups, for example to be chosen from the group comprising methyl, ethyl, ethenyl, phenyl or toluyl. Examples of such melamine derivatives are N,N′,N″-triphenylmelamine. Another example of a melamine derivative is melamine cyanurate. In the context of this application a “melamine condensation product” is understood to be a compound in which two or more melamine compounds are connected to one another, for example melam, melem, melon and higher oligomers and menthone, which can for example be obtained using the process described in WO 96/16948.
Preferably, melamine, melamine cyanurate, melamine phosphate, melam, melem or mixtures thereof are chosen as component(B).
Suitable for use as the melamine-phosphorus compound (AB) are compounds like melamine phosphates, for example melamine pyrophosphate and melamine polyphosphate.
The flame-retardant composition according to the invention is used in polycondensate compositions in concentrations between 1 and 50% (relative to the total weight of the polycondensate composition), preferably between 10 and 40%. The concentration can in principle be determined experimentally by a person skilled in the art. The ratio of components (A), (B), (AB) and (C) may also vary within a wide range. The concentration of organic phosphorus compound (component A) may vary within a wide range, f
Bos Martinus L. M.
Menting Henrica N. A. M.
Roovers William A. C.
Van Der Spek Pieter A.
Van Gurp Marnix
DSM IP Assets B.V.
Pillsbury & Winthrop LLP
Szekely Peter
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