Flame-proof polyester molding compositions comprising ZnS

Details Flame-proof polyester molding compositions comprising ZnS Flame-proof polyester molding compositions comprising ZnS

2002-06-24

2004-08-24

Sanders, Kriellion A. (Department: 1714)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S101000, C524S127000, C524S420000, C524S487000, C524S494000

Reexamination Certificate

active

06780905

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to halogen-free, flame-proof polyester molding compositions. The present invention further relates to the use of said molding compositions for the production of moldings, sheeting or fibers, and to the moldings, sheeting or fibers themselves.
SUMMARY OF THE INVENTION
A thermoplastic molding composition having good flame retarding properties and thermal stability is disclosed. The composition contains A) one or more members selected from the group consisting of polyester, polycarbonate and polyester-carbonate, B) a flame retardant component containing a nitrogen compound and a phosphorus compound C) zinc sulphide and optional functional additives and fillers and/or reinforcing agents. The composition is suitable for the preparation molded articles, sheeting or fibers.
BACKGROUND OF THE INVENTION
Polyester molding compositions which are rendered flame-proof are of considerable importance in the electrical/electronics field and are used for the production of supports for voltage-carrying parts, for example. Apart from good flame-resistance, these components also have to have good mechanical and electrical properties, and the provision of halogen-free molding compositions is increasingly being required.
For electrical and electronic applications in particular, it is important that the plastics molding compositions used have no negative effects on the corrosion behavior of metals or alloys which are in direct contact with them, in order to prevent the malfunction of components.
Since polyester molding compositions are often subjected to elevated temperatures of continuous use in applications such as these, the resistance of the molding composition to ageing caused by hot air is also an important aspect. This includes the discoloration behavior of plastic molding compositions at elevated temperatures of continuous use, wherein a discernible darkening of corresponding plastics moldings is generally undesirable, particularly for electrical and electronic components which are often produced in light colors. In this respect, for example, it has been shown that plastics molding compositions which contain resorcinol diphosphate in particular result in discoloration due to hot air ageing. The migration of constituents of plastics moldings is also undesirable, since this may result in a subsequent change in properties, such as deposits on the contacts of voltage-carrying parts, mechanical losses, or losses in the flame-resistance of the plastics molding composition or of the plastics molding.
Some developments have already been made in the past in this area.
Thus JP-A 3-281 652 discloses polyethylene terephthalate resins which contain a melamine-cyanuric acid addition product and a phosphate or phosphonate as flame retardants, as well as filler materials.
JP-A 6-157 880 discloses reinforced polyethylene terephthalates which contain melamine cyanurate and a phosphorus compound as flame retardants.
JP-A 9-157 503 discloses flame-proof polyester compositions which contain melamine cyanurate, esters of phosphoric acid and special de-molding agents.
Reinforced, flame-proof polyester components are known from EP-A 903 370 which contain a combination of melamine pyrophosphate and a phosphate oligomer.
WO 00/11085 discloses polyester molding compositions which contain melamine cyanurate, a phosphate and special de-molding agents.
WO 00/11 071 discloses polyester compositions which contain nitrogen compounds, phosphorus compounds, metal salts and stabilizers.
However, there is still a need for polyester molding compositions which are distinguished by an improved combination of good mechanical properties and flame retardant properties, good corrosion behavior, good electrical properties and good stability to hot air ageing.
DETAILED DESCRIPTION OF THE INVENTION
Surprisingly, it has now been found that polyester molding compositions which contain a flame retardant combination comprising amounts according to the invention of an organic phosphate, wherein bisphenol A diphosphate is most particularly preferred, and an organic nitrogen compound, wherein melamine cyanurate is most particularly preferred, in combination with zinc sulphide, exhibit the desired range of properties.
The present invention thus relates to flame-resistant molding compositions containing
A) one or more polyesters,
B) 10 to 40% by weight, preferably 17 to 24% by weight, most preferably 19 to 24% by weight, of a flame retardant component containing
B.1) a nitrogen compound, preferably a melamine compound, and
B.2) a phosphorus compound of formula (I)
 wherein
R
1
to R
20
, independently of each other, denote hydrogen or a linear or branched C
1-6
alkyl group,
n denotes an average value of 0.5 to 50, and
B in each case denotes a C
1
-C
12
alkyl, preferably methyl, or a halogen, preferably chlorine and/or bromine,
q denotes numbers which, independently of each other, represent 0, 1 or 2,
X denotes a single bond, C═O, S, O, SO
2
, C(CH
3
)
2
, a C
1
-C
5
alkylene, a C
2
-C
5
alkylidene, a C
5
-C
6
cycloalkylidene or a C
6
-C
12
arylene, on to which further aromatic rings, which optionally contain hetero atoms, may be condensed, or a radical corresponding to formulae (II) or (III)
 wherein
Y denotes carbon and
R
21
and R
22
, independently of each other, denote hydrogen or a C
1
-C
6
alkyl, preferably hydrogen, methyl or ethyl, which may be selected individually for each Y,
m denotes an integer from 4 to 7, preferably 4 or 5, with the proviso that R
21
and R
22
simultaneously denote alkyl on at least one Y atom,
C) 0.01 to 5% by weight, preferably 0.1 to 4% by weight, most preferably 0.4 to 3.5% by weight, of zinc sulphide,
D) 0 to 40%, preferred 0 to 30%, very preferred 0 to 10% relative to weight of the composition of at least one functional additive.
E) 0 to 50% by weight, preferably 10-40% by weight, most preferably 10-35% by weight, of one or more fillers and/or reinforcing agents,
wherein the sum of the proportions of the components adds up to 100% by weight.
Component A
Polyesters in the sense of the present invention are polyalkylene terephthalates, i.e. reaction products of dicarboxylic acids, preferably aromatic dicarboxylic acids, or reactive derivatives thereof (e.g. dimethyl esters or anhydrides) and aliphatic, cycloaliphatic or araliphatic diols, and mixtures of said reaction products, or completely aromatic polyesters which are described in detail below.
Polyalkylene terephthalates may be produced by known methods from terephthalic acid (or reactive derivatives thereof) and aliphatic or cycloaliphatic diols containing 2 to 10 C atoms (Kunststoff-Handbuch, Volume VIII, pages 695 et seq., Karl-Hanser-Verlag, Munich 1973).
The preferred polyalkylene terephthalates contain at least 80, preferably 90 mol % with respect to the dicarboxylic acid, of terephthalic acid radicals, and at least 80, preferably at least 90 mol % with respect to the diol component, of ethylene glycol and/or 1,3-propanediol and/or 1,4-butanediol radicals.
In addition to terephthalic acid radicals, the preferred polyalkylene terephthalates may contain up to 20 mol % of radicals of other aromatic dicarboxylic acids containing 8 to 14 C atoms, or of aliphatic dicarboxylic acids containing 4 to 12 C atoms, such as radicals of phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4′-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid or cyclohexane-diacetic acid.
Apart from ethylene or 1,3-propanediol or 1,4-butanediol radicals, the preferred polyalkylene terephthalates may contain up to 20 mol % of other aliphatic diols comprising 3 to 12 C atoms or cycloaliphatic diols comprising 6 to 21 C atoms, e.g. radicals of 1,3-propanediol, 2-ethylpropanediol-1,3, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, cyclohexane-dimethanol-1,4,3-methylpentanediol-2,4,2-methylpentanediol-2,4, 2,2,4-trimethylpentanediol-1,3 and 1,6,2-ethylhexanediol-1,3, 2,2-diethylpropanediol-1,3, 2,5-hexanediol, 1,4-di-(&bgr;-hydroxyethoxy)-benzene, 2,2-bi

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