Compositions – Fire retarding – For solid synthetic polymer and reactants thereof
Reexamination Certificate
1999-01-29
2002-04-02
Warden, Jill (Department: 1731)
Compositions
Fire retarding
For solid synthetic polymer and reactants thereof
C252S601000, C524S126000
Reexamination Certificate
active
06365071
ABSTRACT:
This Application is a 371 of PCT/EP97/01664 filed Apr. 2, 1997 and claiming priority to German application 19614424 filed Apr. 12, 1996.
BACKGROUND
The invention relates to a synergistic flame retardant combination comprising calcium, aluminum or zinc phosphinates and certain synergistic, nitrogen-containing compounds.
Polymers are frequently made flame-resistant by adding phosphorus-containing or halogen-containing compounds, or mixtures thereof, to these polymers. Mixtures of phosphorus- and nitrogen-containing compounds are often also used as flame retardants.
Alkali metal salts of phosphinic acids have already been proposed as flame-retarding additives for polyesters (DE-A-2 252 258). They must be incorporated in amounts of up to 30% by weight and in some cases have an unfavorable corrosion-promoting effect on the processing equipment.
In addition, the salts of phosphinic acids with an alkali metal or with a metal from the second or third main group or subgroup of the Periodic Table have been used to produce flame-retardant polyamide molding compositions, especially the zinc salts (DE-A-2 447 727).
Calcium phosphinates and aluminum phosphinates have proven particularly effective in polyesters (EP-A-699 708). However, the preparation of these phosphinates on an industrial scale is relatively complex and expensive, thereby limiting very greatly the possibilities of using the products as flame retardants for plastics.
Combinations of the abovementioned phosphinic salts with the nitrogen bases melamine, dicyandiamide and guanidine have also been proposed as flame retardants for various plastics (EP-A-6 568). In this context, mixtures with defined molar proportions of phosphorus and nitrogen have been found to be particularly effective flame retardants.
However, the abovementioned nitrogen compounds have a very disadvantageous effect on the pattern of properties of the plastics, or are difficult or even impossible to process in certain plastics (e.g. polyester and polyamide). Examples of the disadvantages are poor thermal stability, excessive volatility, strong basicity and lack of compatibility with the plastic.
It has now surprisingly been found that certain nitrogen compounds having higher thermal stability and lower volatility, despite in some cases a lower nitrogen content, than those specified in EP-A-6 568 exhibit a particularly good flameproofing action in combination with calcium phosphinates, aluminum phosphinates and zinc phosphinates, and lend themselves very well to processing with thermoplastics. The mixtures of these nitrogen compounds with the Ca, Al and Zn phosphinates give rise, through a synergistic effect, to markedly more cost-effective flameproofing for thermoplastic polymers, especially for polyesters, than the phosphinates on their own.
SUMMARY
The invention thus provides a synergistic flame retardant combination for thermoplastic polymers, especially for polyesters, which comprises as component A a phosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II) and/or polymers thereof,
in which
R
1
, R
2
are C1-C
6
-alkyl, preferably C
1
-C
4
-alkyl, and are linear or branched, examples being methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl; or phenyl;
R
3
is C
1
-C
10
-alkylene and is linear or branched, examples being methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, n-dodecylene; C
6
-C
10
-arylene, examples being phenylene, naphthylene; C
6
-C
10
-alkylarylene, examples being methylphenylene, ethylphenylene, tert-butylphenylene, methyinaphthylene, ethylnaphthylene, tert-butylnaphthylene; C
6
-C
10
-arylalkylene, examples being phenylmethylene, phenylethylene, phenylpropylene, phenylbutylene;
M is calcium ions, aluminum ions, zinc ions, preferably aluminum ions;
m 2 or 3;
n 1 or 3;
x 1 or 2
and comprises as component B a nitrogen compound of the formula (III) to (VIII) or a mixture of the compounds designated by the formulae,
in which R
4
, R
5
and R
6
can be defined as follows: hydrogen, C
1
-C
8
-alkyl, C
5
-C
16
-cycloalkyl or -alkylcycloalkyl, possibly substituted by a hydroxyl or a C
1
-C
4
-hydroxyalkyl function, C
2
-C
8
-alkenyl, C
1
-C
8
-alkoxy, -acyl, -acyloxy, C
6
-C
12
-aryl and also —O—R
4
and —N(R
4
)R
5
(with the exception of melamine, R
4
to R
6
═H) or are N-alicyclic or N-aromatic, where N-alicyclic denotes cyclic N compounds such as pyrrolidine, piperidine, imidazolidine, piperazine, etc., and N-aromatic denotes heteroaromatic ring compounds such as pyrrole, pyridine, imidazole, pyrazine, etc.
R
7
, R
8
, R
9
, R
10
and R
11
are the same groups as R
4
to R
6
, with the exception of the substituents —N(R
4
)R
5
, N-alicyclic and N-aromatic.
DETAILED DESCRIPTION
In the text below the term “phosphinic salt” denotes salts of phosphinic and diphosphinic acids and polymers thereof.
The phosphinic salts, which are prepared in aqueous medium, are essentially monomeric compounds. Depending on the reaction conditions, polymeric phosphinic salts may also be formed.
Examples of suitable phosphinic acids as a constituent of the phosphinic salts are:
dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), benzene-1,4-(dimethylphosphinic acid), methylphenylphosphinic acid and diphenylphosphinic acid.
The salts of the phosphinic acids of the invention can be prepared by known methods that are described in more detail in EP-A-699 708. In such methods, the phosphinic acids are reacted in aqueous solution with metal carbonates, metal hydroxides or metal oxides.
Polymers in the context of the invention are:
1. Polymers of mono- and diolefins, for example polypropylene, polyisobutylene, polybutylene, poly-1-butene, polyisoprene or polybutadiene and also polymers of cycloolefins such as, for example, of cyclopentene or norbornene; and also polyethylene (which may be crosslinked); for example high-density polyethylene (HDPE), polyethylene of high density and high molar mass (HDPE-HMW), polyethylene of high density and ultra high molar mass (HDPE-UHMW), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low density polyethylene (LLDPE), branched low-density polyethylene (BLDPE).
2. Mixtures of the polymers set out under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (e.g. PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (e.g. LDPE/HDPE).
3. Copolymers of monoolefins and diolefins with one another or with other vinyl monomers, for example ethylene-propylene copolymers, linear low-density polyethylene (LLDPE) and mixtures thereof with low-density polyethylene (LDPE), propylene-1-butene copolymers, propyleneisobutylene copolymers, ethylene-1-butene copolymers, etc. Additionally, ethylene-alkyl acrylate copolymers, ethylylene-vinyl acetate copolymers and copolymers thereof with carbon monoxide, or ethylene-acrylic acid copolymers and salts thereof (ionomers), and also terpolymers of ethylene with propylene and a diene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene; and also mixtures of such copolymers with one another and with polymers set out under 1), for example polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers, LDPE/ethylene-acrylic acid copolymers, LLDPE/ethylene-vinyl acetate copolymers, LLDPE/ethylene-acrylic acid copolymers and alternating or random polyalkylene-carbon monoxide copolymers and mixtures thereof with other polymers such as, for example, polyamides.
4. Polystyrene, poly(p-methylstyrene), poly-(&agr;;-methylstyrene).
5. Copolymers of styrene or &agr;-methylstyrene with dienes or acrylic derivatives, for example styrene-butadiene, styrene-acrylonitrile, styrene-alkyl methacrylate, styrene-butadiene alkyl acrylate and methacrylate, styrene-maleic anhydride, styrene-acrylonitrile-methacrylate; mixtures of high impact strength comprising styrene copolymers and another polymer, for example a polyacrylate, a diene polymer
Budzinsky Winfried
Jenewein Elke
Kleiner Hans-Jerg
Wanzke Wolfgang
Clariant GmbH
Cross Latoya
Hanf Scott E.
Jackson Susan S.
Warden Jill
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