Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-09-21
2004-08-10
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S404000, C524S412000, C524S430000, C525S183000
Reexamination Certificate
active
06774174
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to flame retarded high temperature (>280C.) polyamide compositions. More specifically, the present invention relates to reinforced high temperature polyamides including flame retardant (a copolymer of a halostyrene and glycidyl(meth)acrylate), and which are useful in Surface Mount Technology (SMT) applications among others.
BACKGROUND OF THE INVENTION
Flame retarded high temperature polyamides have been used in SMT applications for several years. However because of the absorption of water associated with these polymers, voids are formed therein when they are heated in ovens during processing. The resulting parts are consequently undesirably deformed.
In response to these concerns, high temperature polyamides incorporating flame-retardants have been used and are generally satisfactory for conventional applications. However, there is increasingly a demand for higher melt temperature solder materials that have more stringent property requirements than those of current polyamides in the industry.
A need exists for a high temperature flame retarded polyamide that can withstand higher oven temperatures without the formation of voids and the deformation of plastic parts molded therefrom.
SUMMARY OF THE INVENTION
There is disclosed and claimed herein flame retarded, reinforced high temperature polyamide compositions comprising:
1) about 30 to about 70 weight percent of polyamide with a melt temperature above 280C.;
2) about 5 to about 50 weight percent of reinforcing agent;
3) about 10 to about 30 weight percent of a copolymer of glycidyl(meth)acrylate and bromostyrene ; and,
4) About 1 to 6 weight percent of flame retardant synergist.
In preferred embodiments of the invention, the glycidyl(meth)acrylate is present in amounts of 0.1-15.0 (most preferably 0.3-5.0) weight percent and the bromostyrene is complementally present in the range of 85.0-99.9 (most preferably 95.0-99.7) weight percent in the copolymer; and further the amount of bromine in the copolymer is in the range of 58-70 (most preferably 59-68) weight percent.
The compositions of the invention may optionally contain up to 2 weight percent of a mold release agent and up to 2 weight percent of a heat stabilizer. Moreover, suitable compositions may also contain up to 5 weight percent of toughener (such as rubber, polyethylene, polypropylene, and Surlyn ® ionomer (available from EI DuPont de Nemours and Co.)).
Without intending to limit the generality of the foregoing, any number of nylons, reinforcing agents, synergists and additives may be selected by those of skill in the art and are considered within the scope of this invention. For example, polyamides according to the invention include 9T, 10T, 12T, 46, 6T/66, and 6T/DT, among others. Suitable reinforcing agents include glass or mineral, and flame retardant synergists may be selected from any of antimony trioxide, antimony pentoxide, sodium antimonate, zinc borate and the like. A variety of mold release agents are useful for purposes of this invention, and include wax OP and PED 521, which are commercially available lubricants from Hoechst Celanese AG. Finally, there is a wide range of useful heat stabilizers as can be selected by those having skill in the art, such as Cul.
DETAILED DESCRIPTION OF THE INVENTION
Conventional high temperature, reinforced, flame retarded polyamides use a high melt temperature (>280 C.) polyamide, reinforcing agent (typically fiber glass or mineral), lubricants/mold release agents, heat stabilizers, flame retardant (brominated polystyrene or poly (bromostyrene)), and a flame retardant synergist (typical antimony pentoxide, antimony trioxide, sodium antimonate or Zinc Borate).
In contrast, in this invention the flame retardant (brominated polystyrene or poly (bromostyrene)) was replaced with a copolymer of a halostyrene and glycidyl(meth)acrylate.
Preferably the glycidyl(meth)acrylate flame retardant additive is a random copolymer of a bromostyrene (mono, di- and tri-bromo) [DBS] and glycidyl(meth)acrylate [GMA]. The material used in the examples herein was available under the trade name CP-44 manufactured by the Great Lakes Chemical Co., West Lafayette, Ind. The additive is also described in U.S. Pat. No. 5,565,538, which is incorporated by reference herein.
The replacement of the poly bromostyrene or brominated polystyrene with the CP-44 (poly bromostyrene/glycidyl(meth)acrylate) copolymer yields a significant 5-25 C. or better improvement in the SMT blistering temperature which makes the flame retardant polyamides much more suitable for SMT applications.
REFERENCES:
patent: 5210134 (1993-05-01), Akkapeddi et al.
patent: 5258439 (1993-11-01), Togashi et al.
patent: 5354802 (1994-10-01), Shiwaku et al.
patent: 5369202 (1994-11-01), Atwell et al.
patent: 5543452 (1996-08-01), Nakahashi et al.
patent: 5565538 (1996-10-01), Zingde et al.
patent: 5814384 (1998-09-01), Akkapeddi et al.
patent: 5990244 (1999-11-01), Warakomski et al.
patent: 6037401 (2000-03-01), Tijssen
patent: 6140459 (2000-10-01), Leboeuf et al.
patent: 6146555 (2000-11-01), Gill et al.
patent: 6288145 (2001-09-01), Miyabo
patent: 6414064 (2002-07-01), Matsuoka
patent: 2002/0086928 (2002-07-01), Ouchi
patent: 288 269 (1992-09-01), None
patent: 0 734 413 (1999-03-01), None
patent: 0 999 235 (2000-05-01), None
patent: 999 235 (2000-05-01), None
patent: WO 96/09329 (1996-03-01), None
patent: WO 98/29512 (1998-07-01), None
patent: WO 01/42364 (2001-06-01), None
I. Park, J. Barlow, D. Paul, “The In Situ Reactive Compatibilization of Nylon-6/Polystyrene Blends Using Anhydride Functionalized Polystyrenes”, Journal of Polymer Sequence Part B: Polymer Physics. vol. 30, pp 1021, Jan., 1992.
Journal of Vinyl & Additive Technology, Sep., 1997, vol. 3, No. 3, Functional Copolymers of Dibromostyrene as Flame Retardants for thermoplastic Polyamides and Ppolyesters, W. Fielding, J. Elliott.
W. Fielding, J. Elliott, “Functional Copolymers of Dibromostyrene as Flame Retardants for Thermoplastic Polyamides and Polyesters”, Journal of vinyl & Additive Technology, Sep. 1997, vol. 3, No. 3.
Bohan Jennifer L.
Fielding William Ray
Koshida Reiko
Martens Marvin Michael
E. I. du Pont de Nemours and Company
LandOfFree
Flame-retardant polyamide compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flame-retardant polyamide compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flame-retardant polyamide compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3346528