Patent Application
20110237715
The present invention relates to flame retardant polymer compositions which comprise phosphinic acid salts in combination with so-called sterically hindered nitroxyl derivatives. The compositions are especially useful for the manufacture of flame retardant compositions based on thermoplastic polymers, especially polyolefin homo- and copolymers and copolymers with vinyl monomers.
Flame retardants are added to polymeric materials (synthetic or natural) to enhance the flame retardant properties of the polymers. Depending on their composition, flame retardants may act in the solid, liquid or gas phase either chemically, e.g. as a spumescent by liberation of nitrogen, and/or physically, e.g. by producing a foam coverage. Flame retardants interfere during a particular stage of the combustion process, e.g. during heating, decomposition, ignition or flame spread.
There is still a need for flame retardant compositions with improved properties that can be used in different polymer substrates. Increased standards with regard to safety and environmental requirements result in stricter regulations. Particularly known halogen containing flame retardants no longer match all necessary requirements. Therefore, halogen free flame retardants are preferred, particularly in view of their better performance in terms of smoke density associated with fire. Improved thermal stability and less corrosive behaviour are further benefits of halogen free flame retardant compositions.
It has surprisingly been found that polymer compositions with excellent flame retardant properties are prepared in the event that phosphinic acid salts in combination with so-called sterically hindered amines are added to the polymer substrate.
Further benefits of the compositions of the present invention are improved electrical properties (CTI=comparative tracking index) and improved light stability compared to the use of halogenated FR system. Additionally, the flame retardant compositions are resistant to so-called leaching. The contact with water does not diminish their flame retardant activity.
It has surprisingly been found that by use of the flame retardant compositions according to the invention halogen containing flame retardants, such as decabromodiphenyl oxide, antimony compounds, and fillers may largely be reduced or replaced.
The invention relates to a composition, particularly a flame retardant composition, which comprises
The composition defined above for use as a flame retardant is another embodiment of the invention.
A preferred embodiment of the invention relates to a composition, particularly a flame retardant composition, which comprises
The compositions according to the invention exhibit excellent flame retardant properties at low concentrations of the components a) and b). Dependent on the concentrations of components a) and b) in the polymer substrate, V-2 ratings according to UL-94 (Underwriter's Laboratories Subject 94) and other excellent ratings in related test methods are attained.
The composition, as defined above, comprises the following components:
The term phosphinic acid comprises within its scope derivatives of phosphinic acid, H2P(═O)OH, wherein one or two hydrogen atoms, which are directly attached to the phosphorus atom, have been substituted by organic substituents, such as C1-C8alkyl.
The term phosphinic acid also comprises within its scope the tautomeric form HP(OH)2, wherein the hydrogen atom which is directly attached to the phosphorus atom is substituted by organic substituents, such as C1-C8alkyl.
The term salt of phosphinic acid comprises within its scope preferably a metal salt, for example an alkali metal or alkaline earth metal salt, e.g. the sodium, potassium, magnesium or calcium salt or the iron(II), iron(III), zinc or boron salt.
R1 and R2 defined as C1-C8alkyl is straight or, where possible branched C1-C8alkyl and is for example methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl or 2-ethylhexyl.
R3 defined as C1-C10alkylene is straight chain or, where possible branched C1-C10alkylene, e.g. methylene, ethylene, 1,2- or 1,3-propylene or 1,2-, 1,3- or 1,4-butylene.
R3 defined as C2-C10alkylene interrupted by phenylene is, for example a bivalent group of the partial formulae
wherein the dotted lines point to the carbon atom of attachment.
R3 defined as phenylene is 1,2-, 1,3- or 1,4-phenylene.
R3 defined as (C1-C4alkyl)1-3phenylene is, for example, 1,2-, 1,3- or 1,4-phenylene substituted by 1-3 methyl or ethyl groups.
R3 defined as phenyl-C1-C4alkylene is, for example, one of the above-mentioned C1-C8alkyl groups substituted by phenyl.
According to a preferred embodiment, the composition comprises the aluminium salt of diethylphosphinic acid.
According to an alternative embodiment, the term salt comprises non-metallic salts, e.g. the acid addition salts obtainable by reaction of phosphinic acid with ammonia, amines or amides, e.g. the (C1-C4alkyl)4N+, (C1-C4alkyl)3NH+, (C2-C4alkylOH)4N+, (C2-C4alkylOH)3NH+, (C2-C4alkylOH)2N(CH3)2+, (C2-C4alkylOH)2NHCH3+, (C6H5)4N+, (C6H5)3NH+, (C6H5CH3)4N+, (C6H5CH3)3NH+, NH4+, melamine or guanidine salt.
Among the acid addition salts the ammonium, (C1-C4alkyl)1-4ammonium or (2-hydroxyethyl)1-4ammonium, e.g. tetramethylammonium, tetraethylammonium, the 2-hydroxyethyl-trimethylammonium, melamine or guanidine salt are particularly preferred.
According to a particularly preferred embodiment, the salt of a phosphinic acid (I) is represented by the formula
In which
one of R1 and R2 represents hydrogen or C1-C8alkyl; or both R1 and R2 represent C1-C8alkyl;
M represents (C1-C4alkyl)4N, (C1-C4alkyl)3NH, (C2-C4alkylOH)4N, (C2-C4alkylOH)3NH, (C2-C4alkylOH)2N(CH3)2, (C2-C4alkylOH)2NHCH3, (C6H5)4N, (C6H5)3NH, (C6H5CH3)4N, (C6H5CH3)3NH, NH4, melamine, guanidine, an alkali metal or earth alkali metal ion, or an aluminium, zinc, iron or boron ion;
m is a numeral from 1-3 and indicates the number of positive charges on M; and
n is a numeral from 1-3 and indicates the number of phosphinic acid anions corresponding to Mm+.
According to a particularly preferred embodiment, the salt of a phosphinic acid (I) of Component a) is represented by the formula
Component a) is preferably contained in the flame retardant compositions according to the invention in an amount from 0.1-45.0 wt. %, preferably 1-30.0 wt. %, based on the weight of the polymer substrate component c), and component b) is preferably contained in an amount from 0.05-5.0 wt. %, preferably 0.1-2.0 wt. %. The preferred ratio of components a):b) is in the range 50:1-1:5, preferably 20:1-1:2.
A further embodiment of the invention relates to a mixture, which comprises
The mixture is useful for imparting flame retardancy to a polymer substrate.
A further embodiment of the invention relates to a process for imparting flame retardancy to a polymer substrate, which process comprises adding to a polymer substrate of component c) the above defined mixture of components a) and b).
A suitable tetraalkylpiperidine or tetralkylpiperazine derivative is selected from the group that consists of 2,2,6,6-tetraalkylpiperidine-1-oxides, 1-hydroxy-2,2,6,6-tetraalkylpiperidines, 1-alkoxy-2,2,6,6-tetraalkylpiperidines, 1-acyloxy-2,2,6,6-piperidines, 1-hydroxy-2,2,6,6-tetraalkylpiperazines, 1-alkoxy-2,2,6,6-tetraalkylpiperazines, and 1-acyloxy-2,2,6,6-piperazines.
Such compounds can be illustrated by the partial formulae
Wherein R1-R4 represent C1-C4alkyl, preferably methyl or ethyl. According to preferred embodiments, one of R1 and R2 and one of R3 of R4 represents ethyl and the other ones represent methyl or all of R1-R4 represent methyl; and
E represents hydrogen, C1-C20alkyl, C5-C6cycloalkyl or C2-C20alkyl, C5-C6cycloalkyl or C2-C20alkenyl with additional substituents; or represents the acyl group of a C1-C20monocarboxylic or C2-C20dicarboxylic acid.
In the compounds that correspond to the partial formula a, one of the dotted lines in 4-position of the piperidine represents a bond to hydrogen or an N-substituent and the other one represents a bond to an O-substituent or a C-substituent.
In the alternative, both dotted lines in 4-position of the piperidine represent bonds to hydrogen, O-substituents or C-substituents or represent a double bond to oxygen.
In the compounds that correspond to the partial formula b, the nitrogen in 4-position of the piperazine is bonded to hydrogen or carbon-substituents.
Representative structural formulae are given below:
In these compounds (A)-(R)
E represents hydrogen, C1-C20alkyl, C5-C6cycloalkyl or C2-C20alkyl, C5-C6cycloalkyl or C2-C20alkenyl with additional substituents; or represents the acyl group of a C1-C20monocarboxylic or C2-C20dicarboxylic acid; or, in the alternative, the group >N—O-E is replaced with the group >N—O.
Alkyl is straight or branched and is for example methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.
Cycloalkyl groups include cyclopentyl and cyclohexyl; typical cycloalkenyl groups include cyclohexenyl; while typical aralkyl groups include benzyl, alpha-methyl-benzyl, alpha,alpha-dimethylbenzyl or phenethyl.
E defined as the acyl group of a C1-C20monocarboxylic acid is preferably an acyl radical selected from the group consisting of —C(═O)—H, —C(═O)—C1-C19alkyl, —C(═O)—C2-C19alkenyl, —C(═O)—C2-C4alkenyl-C6-C10aryl, —C(═O)—C6-C10aryl, —C(═O)—O—C1-C6alkyl, —C(═O)—O—C6-C10aryl, —C(═O)—NH—C1-C6alkyl, —C(═O)—NH—C6-C10aryl and —C(═O)—N(C1-C6alkyl)2.
E defined as the acyl group of a C2-C20dicarboxylic acid is, for example, the diacyl radical derived from a monobasic organic acid having C radicals and two acid functions, e.g. a diacyl radical derived from an aliphatic, aromatic or cycloaliphatic dicarboxylic acid.
Suitable aliphatic dicarboxylic acids have from 2 to 40 C-atoms, e.g. oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, pimelic acid, adipic acid, trimethyladipic acid, sebacic acid, azelaic acid and dimeric acid (dimerization products of unsaturated aliphatic carboxylic acids such as oleic acid), alkylated malonic and succinic acids, e.g. octadecylsuccinic acid.
Suitable cycloaliphatic dicarboxylic acids are, for example, 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,3- and 1,4-(dicarboxymethyl)cyclohexane or 4,4′-dicyclohexyldicarboxylic acid.
Preferred members of this group include the acyl radical of oxalic acid, adipic acid, succinic acid, suberic acid, sebacic acid, phthalic acid dibutylmalonic acid, dibenzylmalonic acid or butyl-(3,5-di-tert-butyl-4-hydroxybenzyl)-malonic acid, or bicycloheptenedicarboxylic acid, with succinates, sebacates, phthalates and isophthalates being specific examples.
If E is a divalent acyl radical of a dicarbamic acid, it is for example an acyl radical of hexamethylenedicarbamic acid or of 2,4-toluoylenedicarbamic acid;
T is a straight or branched chain alkylene of 1 to 18 C-atoms, cycloalkylene of 5 to 18 C-atoms, cycloalkenylene of 5 to 18 C-atoms, a straight or branched chain alkylene of 1 to 4 C-atoms substituted by phenyl or by phenyl substituted by one or two alkyl groups of 1 to 4 C-atoms;
b is 1, 2 or 3 with the proviso that b does not exceed the number of C-atoms in T, and when b is 2 or 3, each hydroxyl group is attached to a different C-atoms of T;
R is hydrogen or methyl; and
m is 1 to 4.
In the compounds mentioned above when the variable m is 1,
R2 is hydrogen, C1-C18alkyl or said alkyl optionally interrupted by one or more oxygen atoms, C2-C12alkenyl, C6-C10aryl, C7-C18aralkyl, glycidyl, the monovalent acyl radical of an aliphatic, cycloaliphatic or aromatic carboxylic acid, or a carbamic acid, for example an acyl radical of an aliphatic carboxylic acid having 2-18 C-atoms, of a cycloaliphatic carboxylic acid having 5-12 C-atoms or of an aromatic carboxylic acid having 7-15 C-atoms, or represents groups of the partial formulae
wherein x is 0 or 1,
wherein y is 2-4;
R2 is C1-C12alkylene, C4-C12alkenylene, xylylene, a divalent acyl radical of an aliphatic, cycloaliphatic, araliphatic or aromatic dicarboxylic acid or of a dicarbamic acid, for example an acyl radical of an aliphatic dicarboxylic acid having 2-18 C-atoms, of a cycloaliphatic or aromatic dicarboxylic acid having 8-14 C-atoms, or of an aliphatic, cycloaliphatic or aromatic dicarbamic acid having 8-14 C-atoms;
Or represents groups of the partial formulae
D1 and D2 are independently hydrogen, C1-C8 alkyl, aryl or aralkyl including the 3,5-di-t-butyl-4-hydroxybenzyl radical;
D3 is hydrogen, C1-C18alkyl or C1-C20alkenyl; and
d is 0-20;
R2 is a trivalent acyl radical of an aliphatic, unsaturated aliphatic, cycloaliphatic, or aromatic tricarboxylic acid;
R2 is a tetravalent acyl radical of a saturated or unsaturated aliphatic or aromatic tetracarboxylic acid including 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-but-2-enetetracarboxylic, and 1,2,3,5- and 1,2,4,5-pentanetetracarboxylic acid;
In the compounds mentioned above when the variable p is 1, 2 or 3,
R3 is hydrogen, C1-C12alkyl, C5-C7cycloalkyl, C7-C9aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl;
R4 is hydrogen, C1-C18alkyl, C5-C7cycloalkyl, C2-C8alkenyl, unsubstituted or substituted by cyano, carbonyl or carbamide, or is aryl, aralkyl, or glycidyl, a group of the partial formula —CH2—CH(OH)—Z or of the partial formulae —CO—Z or —CONH—Z, wherein Z is hydrogen, methyl or phenyl, or represents groups of the partial formulae
where h is 0 or 1;
R3 and R4 together, when p is 1, represents alkylene of 4 to 6 C-atoms, or 2-oxo-polyalkylene, or the cyclic acyl radical of an aliphatic or aromatic 1,2- or 1,3-dicarboxylic acid;
R4 is a direct bond or is C1-C12alkylene, C8-C12arylene, xylylene, a —CH2CH(OH)—CH2 group or a group of the partial formula —CH2—CH(OH)—CH2—O—X—O—CH2—CH(OH)—CH2—, wherein X is C2-C10alkylene, C6-C15arylene or C6-C12cycloalkylene; or, provided that R3 is other than alkanoyl, alkenoyl or benzoyl, R4 additionally represents the divalent acyl radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid or dicarbamic acid, or represents the group —CO—; or
R4 represents a group of the partial formula
where T8 and T9 are independently hydrogen, C1-C18alkyl, or T8 and T9 together represent C4-C8alkylene or 3-oxapentamethylene, for instance T8 and T9 together are 3-oxapentamethylene;
R4 is 2,4,6-triazinyl;
n is 1 or 2;
R5 and R′5 are independently C1-C12alkyl, C2-C12alkenyl, C7-C12aralkyl, or R5 additionally represents hydrogen, or R5 and R′5 together are C2-C8alkylene or hydroxyalkylene or C4-C24acyloxyalkylene;
R5 and R′5 together are a group of the partial formula (—CH2)2C(CH2—)2;
R6 is hydrogen, C1-C12alkyl, allyl, benzyl, glycidyl or C2-C6alkoxyalkyl; or
R7 is hydrogen, C1-C12alkyl, C3-C5alkenyl, C7-C9aralkyl, C5-C7cycloalkyl, C2-C4hydroxyalkyl, C2-C6alkoxyalkyl, C6-C10 aryl, glycidyl, a group of the partial formula —(CH2)t—COO-Q or of the partial formula —(CH2)t—O—CO-Q wherein t is 1 or 2, and Q is C1-C4alkyl or phenyl; or
when n is 2,
R7 is C2-C12alkylene, C6-C12arylene, a group of the partial formula
—CH2CH(OH)—CH2—O—X—O—CH2—CH(OH)—CH2—,
Wherein X is C2-C10alkylene, C6-C15arylene or C6-C12cycloalkylene, or a group of the partial formula
—CH2CH(OZ′)CH2—(OCH2—CH(OZ′)CH2)2—,
Wherein Z′ is hydrogen, C1-C18alkyl, allyl, benzyl, C2-C12alkanoyl or benzoyl;
Q1 is —N(R8)— or —O—; E7 is C1-C3 alkylene, the group —CH2—CH(R9)—O— wherein R9 is hydrogen, methyl or phenyl, the group —(CH2)3—NH— or a direct bond;
R10 is hydrogen or C1-C18 alkyl, R8 is hydrogen, C1-C18alkyl, C5-C7cycloalkyl, C7-C12aralkyl, cyanoethyl, C6-C10aryl, the group —CH2—CH(R9)—OH wherein R9 has the meaning defined above; or represents groups of the partial formulae
Wherein G4 is C2-C12alkylene or C6-C12arylene; or R8 is a group of the partial formula -E7-CO—NH—CH2—OR10;
Formula F denotes a recurring structural unit of a polymer where T3 is ethylene or 1,2-propylene, is the repeating structural unit derived from an alpha-olefin copolymer with an alkyl acrylate or methacrylate; for example a copolymer of ethylene and ethyl acrylate, and where k is 2 to 100;
T4 has the same meaning as R4 when p is 1 or 2;
T5 is methyl;
T6 is methyl or ethyl, or T5 and T6 together are tetramethylene or pentamethylene, for instance T5 and T6 are each methyl;
M and Y are independently methylene or carbonyl, and T4 is ethylene where n is 2;
T7 is as defined as R7, and T7 is for example octamethylene where n is 2;
T10 and T11 are independently alkylene of 2 to 12 C-atoms; or T11 represents a group of the partial formula
T12 is piperazinyl, or represents groups of the partial formulae
where R11 is as defined as R3 or additionally represents a group of the partial formula
a, b and c are independently 2 or 3, and f is 0 or 1, for instance a and c are each 3, b is 2 and f is 1; and
e is 2, 3 or 4, for example 4;
T13 is the same as R2 with the proviso that T13 is other than hydrogen when n is 1;
E1 and E2, being different, each are —CO— or —N(E5)— where E5 is hydrogen, C1-C12alkyl or C4-C24alkoxycarbonylalkyl, for instance E1 is —CO— and E2 is —N(E5)-;
E3 is hydrogen, C1-C30alkyl, phenyl, naphthyl, said phenyl or said naphthyl substituted by chlorine or by C1-C4alkyl, or C7-C12phenylalkyl, or said phenylalkyl substituted by C1-C4alkyl of 1 to 4 C-atoms;
E4 is hydrogen, alkyl of 1 to 30 C-atoms, phenyl, naphthyl or phenylalkyl of 7 to 12 C-atoms, or
E3 and E4 together are polymethylene of 4 to 17 C-atoms, or said polymethylene substituted by up to four C1-C4alkyl groups, for example methyl;
E6 is an aliphatic or aromatic tetravalent radical;
R2 of formula (N) is a previously defined when m is 1;
G1 a direct bond, C1-C12 alkylene, phenylene or —NH-G′-NH wherein G′ is C1-C12 alkylene.
Suitable tetraalkylpiperidine or tetralkylpiperazine derivatives are, for example, compounds of the formulae 1-12:
wherein
E1, E2, E3 and E4 are independently C1-C4alkyl, or E1 and E2 are independently C1-C4alkyl and E3 and E4 taken together are pentamethylene, or E1 and E2; and E3 and E4 each taken together are pentamethylene;
R1 is C1-C18alkyl, C5-C12cycloalkyl, a bicyclic or tricyclic hydrocarbon radical of 7 to 12 carbon atoms, C7-C15-phenylalkyl, C6-C10aryl or said aryl substituted by one to three C1-C8alkyl;
R2 is hydrogen or a linear or branched chain C1-C12 alkyl;
R3 is alkylene of 1 to 8 carbon atoms, or R3 is —CO—, —CO—R4—, —CONR2—, or —CO—NR2—R4;
R4 is C1-C8 alkylene;
R5 is hydrogen, linear or branched chain C1-C12alkyl, or represents a group of the partial formula
Or, when R4 is ethylene, two R5 methyl substituents can be linked by a direct bond with the triazine bridging group —N(R5)—R4—N(R5)— forming a piperazin-1,4-diyl group;
R6 is C2-C8alkylene or represents a group of the partial formula
with the proviso that Y is other than —OH when R6 is the structure depicted above;
A is —O— or —NR7— where R7 is hydrogen, straight or branched chain C1-C12alkyl; or R7 is a group of the partial formula
T is phenoxy, phenoxy substituted by one or two C1-C8alkyl or C1-C8alkoxy or —N(R2)2 with the stipulation that R2 is other than hydrogen; or T is a group of the partial formula
Y is —OH, —NH2, —NHR2 where R2 is other than hydrogen; or Y is —NCO, —COOH, oxiranyl, —O-glycidyl, or —Si(OR2)3;
Or the combination R3—Y— is —CH2CH(OH)R2 where R2 is alkyl or said alkyl interrupted by one to four oxygen atoms, or R3—Y— is —CH2OR2; or
Wherein the hindered amine compound is a mixture of N,N′,N′″-tris{2,4-bis[(1-hydrocarbyloxy-2,2,6,6-tetramethylpiperidin-4-yl)alkylamino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine; N,N′,N″-tris{2,4-bis[(1-hydrocarbyloxy-2,2,6,6-tetramethylpiperidin-4-yl)alkylamino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine, and bridged derivatives as described by formulae
R1NH—CH2CH2CH2NR2CH2CH2NR3CH2CH2CH2NHR4 (13)
T-E1-T1 (14)
T-E1 (15)
G-E1-G1-E1-G2 (16)
Where in the tetraamine (13)
R1 and R2 are the s-triazine moiety E; and one of R3 and R4 is the s-triazine moiety E with the other ones of R3 or R4 being hydrogen;
R is methyl, propyl, cyclohexyl or octyl, for instance cyclohexyl;
R5 is C1-C12alkyl, for example n-butyl;
where in the compound of formula (14) and (15), when R is propyl, cyclohexyl or octyl,
T and T1 are each a tetraamine substituted by R1-R4 as is defined for formula 13, where
In which the index n ranges from 1 to 15;
R12 is C2-C12alkylene, C4-C12alkenylene, C5-C7cycloalkylene, C5-C7cycloalkylene-di(C1-C4alkylene), C1-C4alkylene-di(C5-C7cycloalkylene), phenylene-di(C1-C4alkylene) or
C4-C12alkylene interrupted by 1,4-piperazinediyl, —O— or >N—X1 with X1 being C1-C12acyl or
(C1-C12alkoxy)carbonyl or having one of the definitions of R14 given below other than hydrogen; or R12 is a group of the partial formulae:
With X2 being C1-C18alkyl, C5-C12cycloalkyl which is unsubstituted or substituted by 1, 2 or 3 C1-C4alkyl; phenyl which is unsubstituted or substituted by 1, 2 or 3 C1-C4alkyl or C1-C4alkoxy; C7-C9phenylalkyl which is unsubstituted or substituted on the phenyl by 1, 2 or 3 C1-C4alkyl; and
The radicals X3 being independently of one another C2-C12alkylene;
R13, R14 and R15, which are identical or different, are hydrogen, C1-C18alkyl, C5-C12cycloalkyl which is unsubstituted or substituted by 1, 2 or 3 C1-C4alkyl; C3-C18alkenyl, phenyl which is unsubstituted or substituted by 1, 2 or 3 C1-C4alkyl or C1-C4alkoxy; C7-C9phenylalkyl which is unsubstituted or substituted on the phenyl by 1, 2 or 3 C1-C4alkyl; tetrahydrofurfuryl or
C2-C4alkyl which is substituted in the 2, 3 or 4 position by —OH, C1-C8alkoxy, di(C1-C4alkyl)amino or a group of the partial formula:
with Y being —O—, —CH2—, —CH2CH2— or >N—CH3, or —N(R14)(R15) is additionally the group
The radicals A are independently of one another —OR13, —N(R14)(R15) or a group of the partial formula:
R16 is hydrogen, C1-C18alkyl, C3-C18alkenyl, C5-C12cycloalkyl which is unsubstituted or substituted by 1, 2 or 3 C1-C4alkyl; C7-C9phenylalkyl which is unsubstituted or substituted on the phenyl by 1, 2 or 3 C1-C4alkyl; tetrahydrofurfuryl, a group of the partial formula:
or C2-C4alkyl which is substituted in the 2, 3 or 4 position by —OH, C1-C8alkoxy, di(C1-C4alkyl)amino or the group of the partial formula
R11 has one of the definitions given for R16; and
the radicals B have independently of one another one of the definitions given for A.
The tetraalkylpiperidine and tetraalkylpiperazine compounds are known in the art, also known as N-alkoxy hindered amines and NOR-hindered amines or NOR-hindered amine light stabilizers or NOR-HALS, such as the ones disclosed in U.S. Pat. Nos. 5,004,770, 5,204,473, 5,096,950, 5,300,544, 5,112,890, 5,124,378, 5,145,893, 5,216,156, 5,844,026, 6,117,995 or 6,271,377.
U.S. Pat. No. 6,271,377, and Published U.S. application Ser. No. 09/505,529, filed Feb. 17, 2000, and 09/794,710, filed Feb. 27, 2001 disclose hindered hydroxyalkoxyamine stabilizers. Hindered hydroxyalkoxyamine stabilizers are also known as N-hydroxyalkoxy hindered amines, or NORol-HALS.
Representative structures are the following:
Wherein the definitions of R and R′ include N-, O- or C-substituents.
When the group E is —O—C(O)—C1-C18alkyl, the compounds are hydroxylamine esters.
The hydroxylamines are reacted with an acid derivative to form the final hydroxylamine ester. Such esterification processes are known and described in the literature.
The preparation of particularly suitable compounds is described in the International Patent Application WO 01/90113.
According to a preferred embodiment, the tetraalkylpiperidine derivative is selected from the group of 2,2,6,6-tetraalkylpiperidine-1-oxides of the formula
According to a preferred embodiment, the composition comprises as Component b) at least one tetraalkylpiperidine derivative III a, III b, III c or III d,
According to a particularly preferred embodiment, the composition comprises as Component b) at least one tetraalkylpiperidine derivative III a, III b, III c or III d,
According to a preferred embodiment, Component b) consists of at least one tetraalkylpiperidine derivative III c or III d selected from the group consisting of
The above mentioned compounds are partly items of commerce. Representative compounds are marketed by Ciba under the following trade names Flamestab NOR116®, Tinuvin NOR371® or Irgatec CR 76®.
The term polymer substrate comprises within its scope thermoplastic polymers or thermosets.
A list of suitable thermoplastic polymers is given below:
The polymer substrate mentioned above, which comprises polycarbonates or polycarbonate blends is a polycarbonate-copolymer, wherein isophthalate/terephthalate-resorcinol segments are present. Such polycarbonates are commercially available, e.g. Lexan® SLX (General Electrics Co. USA). Other polymeric substrates of component b) may additionally contain in the form as admixtures or as copolymers a wide variety of synthetic polymers including polyolefins, polystyrenes, polyesters, polyethers, polyamides, poly(meth)acrylates, thermoplastic polyurethanes, polysulphones, polyacetals and PVC, including suitable compatibilizing agents. For example, the polymer substrate may additionally contain thermoplastic polymers selected from the group of resins consisting of polyolefins, thermoplastic polyurethanes, styrene polymers and copolymers thereof. Specific embodiments include polypropylene (PP), polyethylene (PE), polyimide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glycolmodified polycyclohexylenemethylene terephthalate (PCTG), polysulphone (PSU), polymethylmethacrylate (PMMA), thermoplastic polyurethane (TPU), acrylonitrilebutadiene-styrene (ABS), acrylonitrile-styrene-acrylic ester (ASA), acrylonitrileethylene-propylene-styrene (AES), styrene-maleic anhydride (SMA) or high impact polystyrene (HIPS).
A preferred embodiment of the invention relates to compositions which comprise as component c) thermoplastic polymers. Preferred thermoplastic polymers include polyolefin homo- and copolymers, copolymers of olefins vinyl monomers, styrenic homopolymers and copolymers thereof.
Advantageously, the melamine and guanidine salts (I) and (II) are ground to a fine powder with an average particle size below 100 μm prior to their application in polymer substrates as it is observed that the flame retardant properties of the inventive compositions are improved by small particle sizes.
The instant invention further pertains to a composition, which comprises, in addition to the components a), b) and c), as defined above, as optional components, additional flame retardants and further additives selected from the group consisting of so-called anti-dripping agents and polymer stabilizers.
Representative phosphorus containing flame retardants are for example:
Tetraphenyl resorcinol diphosphate (Fyrolflex® RDP, Akzo Nobel), resorcinol diphosphate oligomer (RDP), triphenyl phosphate, tris(2,4-di-tert-butylphenyl)phosphate, ethylenediamine diphosphate (EDAP), ammonium polyphosphate, diethyl-N,N-bis(2-hydroxyethyl)aminomethyl phosphonate, hydroxyalkyl esters of phosphorus acids, salts of hypophosphoric acid (H3PO2), particularly the Ca2+, Zn2+, or Al3+ salts, tetrakis(hydroxymethyl)phosphonium sulphide, triphenylphosphine, derivatives of 9,10-dihydro-9-oxa-10-phosphorylphenanthrene-10-oxide (DOPO), and phosphazene flame-retardants.
Nitrogen containing flame retardants are, for example, isocyanurate flame retardants, such as polyisocyanurate, esters of isocyanuric acid or isocyanurates. Representative examples are hydroxyalkyl isocyanurates, such as tris-(2-hydroxyethyl)isocyanurate, tris(hydroxymethyl)isocyanurate, tris(3-hydroxy-n-proyl)isocyanurate or triglycidyl isocyanurate.
Nitrogen containing flame-retardants include further melamine-based flame-retardants. Representative examples are: melamine cyanurate, melamine borate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine ammonium polyphosphate, melamine ammonium pyrophosphate, dimelamine phosphate and dimelamine pyrophosphate.
Further examples are: benzoguanamine, tris(hydroxyethyl)isocyanurate, allantoin, glycoluril, melamine cyanurate, melamine phosphate, dimelamine phosphate, urea cyanurate, ammonium polyphosphate, a condensation product of melamine from the series melem, melam, melon and/or a higher condensed compound or a reaction product of melamine with phosphoric acid or a mixture thereof.
Representative organohalogen flame retardants are, for example:
Polybrominated diphenyl oxide (DE-60F, Great Lakes Corp.), decabromodiphenyl oxide (DBDPO; Saytex® 102E), tris[3-bromo-2,2-bis(bromomethyl)propyl]phosphate (PB 370®, FMC Corp.), tris(2,3-dibromopropyl)phosphate, tris(2,3-dichloropropyl)phosphate, chlorendic acid, tetrachlorophthalic acid, tetrabromophthalic acid, poly-α-chloroethyl triphosphonate mixture, tetrabromobisphenol A bis(2,3-dibromopropyl ether) (PE68), brominated epoxy resin, ethylene-bis(tetrabromophthalimide) (Saytex® BT-93), bis(hexachlorocyclopentadieno)cyclooctane (Declorane Plus®), chlorinated paraffins, octabromodiphenyl ether, hexachlorocyclopentadiene derivatives, 1,2-bis(tribromophenoxy)ethane (FF680), tetrabromo-bisphenol A (Saytex® RB100), ethylene bis-(dibromo-norbornanedicarboximide) (Saytex® BN-451), bis-(hexachlorocycloentadeno) cyclooctane, PTFE, tris-(2,3-dibromopropyl)-isocyanurate, and ethylene-bis-tetrabromophthalimide.
The organohalogen flame retardants mentioned above are routinely combined with an inorganic oxide synergist. Most common for this use are zinc or antimony oxides, e.g. Sb2O3 or Sb2O5. Boron compounds are suitable, too.
Representative inorganic flame retardants include, for example, aluminum trihydroxide (ATH), boehmite (AlOOH), magnesium dihydroxide (MDH), zinc borates, CaCO3, (organically modified) layered silicates, (organically modified) layered double hydroxides, and mixtures thereof.
The above-mentioned additional flame retardant classes are advantageously contained in the composition of the invention in an amount from about 0.5% to about 60.0% by weight of the organic polymer substrate; for instance about 1.0% to about 40.0%; for example about 5.0% to about 35.0% by weight of the polymer or based on the total weight of the composition.
According to another embodiment, the invention relates to a composition which additionally comprises as additional component so-called anti-dripping agents.
These anti-dripping agents reduce the melt flow of the thermoplastic polymer and inhibit the formation of drops at high temperatures. Various references, such as U.S. Pat. No. 4,263,201, describe the addition of anti-dripping agents to flame retardant compositions.
Suitable additives that inhibit the formation of drops at high temperatures include glass fibers, polytetrafluoroethylene (PTFE), high temperature elastomers, carbon fibers, glass spheres and the like.
The addition of polysiloxanes of different structures has been proposed in various references; cf. U.S. Pat. Nos. 6,660,787, 6,727,302 or 6,730,720.
Stabilizers are preferably halogen-free and selected from the group consisting of nitroxyl stabilizers, nitrone stabilizers, amine oxide stabilizers, benzofuranone stabilizers, phosphite and phosphonite stabilizers, quinone methide stabilizers and monoacrylate esters of 2,2′-alkylidenebisphenol stabilizers.
As mentioned above, the composition according to the invention may additionally contain one or more conventional additives, for example selected from pigments, dyes, plasticizers, antioxidants, thixotropic agents, levelling assistants, basic co-stabilizers, metal passivators, metal oxides, organophosphorus compounds, further light stabilizers and mixtures thereof, especially pigments, phenolic antioxidants, calcium stearate, zinc stearate, UV absorbers of the 2-hydroxy-benzophenone, 2-(2′-hydroxyphenyl)benzotriazole and/or 2-(2-hydroxyphenyl)-1,3,5-triazine groups.
Preferred additional additives for the compositions as defined above are processing stabilizers, such as the above-mentioned phosphites and phenolic antioxidants, and light stabilizers, such as benzotriazoles. Preferred specific antioxidants include octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (IRGANOX 1076), pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (IRGANOX 1010), tris(3,5-di-tert-butyl-4-hydroxyphenyl)isocyanurate (IRGANOX 3114), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (IRGANOX 1330), triethyleneglycol-bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (IRGANOX 245), and N,N′-hexane-1,6-diyl-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] (IRGANOX 1098). Specific processing stabilizers include tris(2,4-di-tert-butylphenyl)phosphite (IRGAFOS 168), 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (IRGAFOS 126), 2,2′,2″-nitrilo[triethyl-tris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)]phosphite (IRGAFOS 12), and tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4′-diylbisphosphonite (IRGAFOS P-EPQ). Specific light stabilizers include 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN 234), 2-(5-chloro(2H)-benzotriazole-2-yl)-4-(methyl)-6-(tert-butyl)phenol (TINUVIN 326), 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN 329), 2-(2H-benzotriazole-2-yl)-4-(tert-butyl)-6-(sec-butyl)phenol (TINUVIN 350), 2,2′-methylenebis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol) (TINUVIN 360), and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (TINUVIN 1577), 2-(2′-hydroxy-5′-methylphenyl)benzotriazole (TINUVIN P), 2-hydroxy-4-(octyloxy)benzophenone (CHIMASSORB 81), 1,3-bis-[(2′-cyano-3′,3′-diphenylacryloyl)oxy]-2,2-bis-{[(2′-cyano-3′,3′-diphenylacryloyl)oxy]methyl}-propane (UVINUL 3030, BASF), ethyl-2-cyano-3,3-diphenylacrylate (UVINUL 3035, BASF), and (2-ethylhexyl)-2-cyano-3,3-diphenylacrylate (UVINUL 3039, BASF).
The additives mentioned above are preferably contained in an amount of 0.01 to 10.0%, especially 0.05 to 5.0%, relative to the weight of the polymer substrate of Component c).
The incorporation of the components defined above into the polymer component is carried out by known methods such as dry blending in the form of a powder, or wet mixing in the form of solutions, dispersions or suspensions for example in an inert solvent, water or oil. The additive components a) and b) and optional further additives may be incorporated, for example, before or after molding or also by applying the dissolved or dispersed additive or additive mixture to the polymer material, with or without subsequent evaporation of the solvent or the suspension/dispersion agent. They may be added directly into the processing apparatus (e.g. extruders, internal mixers, etc.), e.g. as a dry mixture or powder, or as a solution or dispersion or suspension or melt.
The addition of the additive components to the polymer substrate can be carried out in customary mixing machines in which the polymer is melted and mixed with the additives. Suitable machines are known to those skilled in the art. They are predominantly mixers, kneaders and extruders.
The process is preferably carried out in an extruder by introducing the additive during processing.
Particularly preferred processing machines are single-screw extruders, contra-rotating and co-rotating twin-screw extruders, planetary-gear extruders, ring extruders or co-kneaders. Processing machines provided with at least one gas removal compartment can be used to which a vacuum can be applied.
Suitable extruders and kneaders are described, for example, in Handbuch der Kunststoffextrusion, Vol. 1 Grundlagen, Editors F. Hensen, W. Knappe, H. Potente, 1989, pp. 3-7, ISBN:3-446-14339-4 (Vol. 2 Extrusionsanlagen 1986, ISBN 3-446-14329-7).
For example, the screw length is 1-60 screw diameters, preferably 35-48 screw diameters. The rotational speed of the screw is preferably 10-600 rotations per minute (rpm), preferably 25-300 rpm.
The maximum throughput is dependent on the screw diameter, the rotational speed and the driving force. The process of the present invention can also be carried out at a level lower than maximum throughput by varying the parameters mentioned or employing weighing machines delivering dosage amounts.
If a plurality of components is added, these can be premixed or added individually.
The additive components a) and optional further additives can also be sprayed onto the polymer substrate b). The additive mixture dilutes other additives, for example the conventional additives indicated above, or their melts so that they can be sprayed also together with these additives onto the polymer substrate. Addition by spraying during the deactivation of the polymerisation catalysts is particularly advantageous; in this case, the steam evolved may be used for deactivation of the catalyst. In the case of spherically polymerised polyolefins it may, for example, be advantageous to apply the additives of the invention, optionally together with other additives, by spraying.
The additive components a) and b) optional further additives can also be added to the polymer in the form of a master batch (“concentrate”) which contains the components in a concentration of, for example, about 1.0% to about 40.0% and preferably 2.0% to about 20.0% by weight incorporated in a polymer. The polymer is not necessarily of identical structure than the polymer where the additives are added finally. In such operations, the polymer can be used in the form of powder, granules, solutions, and suspensions or in the form of lattices.
Incorporation can take place prior to or during the shaping operation. The materials containing the additives of the invention described herein preferably are used for the production of molded articles, for example roto-molded articles, injection molded articles, profiles and the like, and especially a fibre, spun melt non-woven, film or foam.
The components a) and b) are admixed to the polymer substrate c) in concentrations of 0.1-45.0 wt. %, preferably 0.1-30.0 wt. % for component a) and 0.05-5.0 wt. %, preferably 0.1-2.0 wt. % for component b).
The preferred ratio of components a):b) is in the range 50:1-1:5, preferably 20:1-1:2.
A particularly preferred embodiment of the invention relates to a composition, particularly a flame retardant composition, which comprises
The following examples illustrate the invention, but are not to be construed to limit the scope thereof.
Moplen® HF500 N: Commercial grade polypropylene (Basell, Germany);
Tinuvin® NOR371 (NOR1): Commercial product (Ciba Inc., Switzerland);
Flamestab® NOR116 (NOR2): Commercial product (Ciba Inc., Switzerland);
Exolit OP® 1240: Diethylphosphinic acid aluminium salt (Clariant, Switzerland).
UL 94 test for “Flammability of Plastic Materials for Parts in Devices and Appliances”, 5th edition, Oct. 29, 1996. Ratings according to the UL 94 V test are compiled in the following table (time periods are indicated for one specimen):
Referential Compositions according to Referential Examples 1-4 and Inventive Compositions according to Examples 1-4: Polypropylene homopolymer (MOPLEN HF 500 N) is extruded on a co-rotating twin-screw extruder ZSK25 (Coperion Werner & Pfleiderer) at a temperature of Tmax: 230° C., a throughput rate of 4 kg/h and a rotational speed of 100 rotations per minute (rpm). To MOPLEN HF 500 N are added a basic-level stabilization composition (0.05% Ca-stearate+0.5% IRGANOX® B225; IRGANOX® B225 is a 1:1 mixture of IRGAFOS® 168 and IRGANOX® 1010) and the additives listed in Table 1.
After cooling in a water bath, the polymer strand is granulated. UL94-V test specimen (bars 125×12.5 mm, thickness=1.6 mm) and 1.0 mm plaques according to DIN 4102-B2 are prepared by injection molding on an Arburg 370S injection molding machine at 230° C. Films according to DIN 4102-B2 are obtained by compression molding.
The test samples are investigated for their flame retardant behaviour in accordance with UL94-V standards after conditioning for 48 h at 23° C. and 50% relative humidity.
Additional UL94-V tests are performed after exposure of the test specimen to deionized water at 70° C. for a period of 7 days (leaching test). Subsequently, the test bars are dried in a vacuum oven at 105° C. for 24 h. Results obtained after leaching are presented in Table 2.
a)Number of tests (out of five tests) in which burning drips dripping from the ignited test bar ignite cotton placed underneath the test bar according to the UL94 test norm.
It can be concluded from the results reported above that the polymer compositions according to the present invention show excellent flame retardancy with self-extinguishing properties. While none of the referential compositions comprising a single additive show significant flame retardant behaviour, the inventive combinations of a phosphinate salt and a representative sterically hindered N-alkoxyamine provide efficient flame retardancy.
a)Number of tests (out of five tests) in which burning drips dripping from the ignited test bar ignite cotton placed underneath the test bar according to the UL94 test norm. It can be concluded from the results presented in Table 2 that a representative polymer composition according to the present invention is characterized by excellent leaching resistance against water. Essentially no weight loss and no change of sample thickness is observed after leaching tests. Inventive Example 3 shows that UL94 V-2 rating is retained during a leaching test.
This application claims benefit of U.S. app. No. 61/317,310, filed Mar. 25, 2010, the contents of which are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61317310 | Mar 2010 | US |
