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
2000-01-27
2001-03-27
Medley, Margaret (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...
C524S436000
Reexamination Certificate
active
06207741
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a flame resistant thermoplastic acrylic composition comprising an acrylic polymer matrix, filler and a combination of flame retardant materials. The material is in thin solid surface form which when subjected to a flame is self-extinguishing and generates a minimum amount of smoke.
2. Description of the Prior Art
In developing flame retardant polymeric compositions it is known, as disclosed in U.S. Pat. No. 4,243,579, to use combinations of halogen-containing compounds and antimony oxide to impart flame retardant properties. However, there are several disadvantages in the use of such combinations, which include dense smoke production on burning, and the existence of afterglow on burning. ASTM E-84 specifies a standard test method for surface burning characteristics of building materials. The test results cover two parameters; flame spread and smoke developed during a 10-minute fire exposure. Inorganic cement board and red oak flooring are used as comparative standards and their responses are assigned arbitrary values of 0 and 100 respectively. The classifications are as follows for interior wall and ceilings.
ASTME E-84 TEST CLASSIFICATIONS
Class
Flame Spread
Smoke Developed
I
0-25
0-450
II
26-75
0-450
III
76-200
0-450
While thick sheets of known solid surface materials may meet Class I standards, sheets having a thickness of less than about 0.25 inch (0.635 cm) have not met the Class I standard. Accordingly, there is a need to provide new compositions, which meet the ASTM E-84 Class I test.
Summary of the Invention
It has been found that Class I ASTM E-84 test standards are met by providing thin solid surface materials from thermoplastic compositions containing an acrylic polymer matrix having dispersed therein controlled amounts of magnesium hydroxide as the filler, and antimony oxide and a brominated flame retardant.
Description of the Preferred Embodiments
Preferred embodiments of the acrylic resin based compositions contain from about 45% to 65% by weight based on the total weight of the composition of magnesium hydroxide, from 0.15% to 15% by weight of antimony oxide, and 5% to 20% by weight of a halogenated flame retardant.
The antimony hydroxide may be selected from any of tri-, tetra-, penta-antimony oxide or combinations thereof. The halogenated flame retardant is selected from brominated compounds such as tetradecabromophenoxybenzene, pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A and its derivatives, tribromoneopentyl alcohol, hexabromocyclododecane, tribromophenyl allyl ether, tetrabromodipentaerythritol, bis (tribromophenoxy)ethane, ethylene bis(dibromonorbomane) dicarboximide, tetrabromobispenol S, bis(2,3-dibromopropyl)ether, and poly(pentabromobenzyl) acrylate. These flame retardants are commercially available.
The acrylic resins useful in the present invention are commercially available thermoplastic resins that can be formed into high performance decorative solid surface material. A particularly good and especially preferred resin which meets all of the above properties is poly(methyl methacrylate).
As used herein, the term “thermoplastic” refers to polymers that are reversibly deformable (able to be softened) after being heated above their softening or glass transition temperatures and then cooled. These materials are capable of being repeatedly melt processed in plastic manufacturing machinery. As is generally accepted by those skilled in the art, thermplastic polymers include polymethacrylates and methyl methacrylates such as C
2
-C
22
alkyl(meth) acrylate monomers. More particularly, the thermoplastic matrix material may be an impact modified polymethacrylate. Suitable impact modifiers include, for example, elastomeric polymers such as graft polymers of methyl methacrylate and styrene or butadiene, copolymers of butyl acrylate and methyl acrylaste or other well known impact modifiers present in amounts from 0 to 25 weight percent.
The presence of significant amounts of fillers other than magnesium hydroxide detract from the adventitious flame retardant attributes of the products of this invention. Accordingly, the products of this invention should be substantially free of such fillers.
It is permissable to include in the products of this invention controlled amounts of additives such as pigmnents, dyes, parting agents, fluidizing agents, viscosity control agents, curing agents, antioxidants, and the like as are known to those of ordinary skill in the art in amounts that do not detract from the flame retardant attributes of the products of this invention.
The solid surface material maintains its pleasing aesthetics, is easy to maintain and provides excellent flame retardance in a variety of end uses such as bathroom wet walls, wall partitions or wall cladding.
The following examples in which parts and percentages are by weight unless otherwise specified further illustrate products of the present invention. All samples have a thickness of 0.125 in.( 0.3175 cm.)
REFERENCES:
patent: 3361705 (1968-01-01), Kay
patent: 3816367 (1974-06-01), Larkin et al.
patent: 4067847 (1978-01-01), Yui et al.
patent: 4243579 (1981-01-01), Keogh
patent: 4740537 (1988-04-01), Silver
patent: 4764539 (1988-08-01), Ladang
patent: 5036121 (1991-07-01), Coaker et al.
patent: 5670748 (1997-09-01), Singue et al.
patent: 0244866 (1987-11-01), None
patent: 0364717 (1990-04-01), None
patent: 2-32114 (1990-02-01), None
patent: 6-80811 (1994-03-01), None
patent: 7-228775 (1995-08-01), None
patent: 11172101A (1999-06-01), None
patent: 95/18178 (1995-07-01), None
E. I. Du Pont de Nemours and Company
Medley Margaret
LandOfFree
Thin flame resistant solid surface material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thin flame resistant solid surface material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin flame resistant solid surface material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454632