Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phosphorus-containing reactant
Reexamination Certificate
2002-10-15
2004-05-04
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phosphorus-containing reactant
C528S422000, C528S423000
Reexamination Certificate
active
06730773
ABSTRACT:
The invention relates to a salt of a melamine condensation product and a phosphorus-containing acid, a method for the preparation of this salt and the use thereof as a flame retardant in flame-retardant polymer compositions.
The use of the combination of a melamine condensation product and a phosphorus compound in flame-retardant polymer compositions is known from NL-B-1006525. Said patent describes a flame-retardant polyester composition in which a nitrogen-containing compound and a phosphorus-containing compound form the flame-proofing combination. The disadvantage of the polymer composition according to NL-B-1006525 is that the phosphorus-containing compound and the nitrogen-containing compound must be prepared separately. As the nitrogen-containing compound in NL-B-1006525 use is made inter alia of melam. However, the preparation of almost pure melam is a multi-step process that is difficult to carry out and economically little attractive. In a first step melamine and a catalyst are used to form a salt of melam and the relevant catalyst. From this salt almost pure melam is to be obtained in a number of subsequent steps. Known catalysts mentioned in the literature are zinc chloride and sulphonic acids such as paratoluene sulphonic acid.
The object of the invention is to obtain a flame retardant on the basis of a melamine condensation product and a phosphorus-containing compound which can be prepared in an economic way in a single process step. In particular the object of the invention is to obtain a flame retardant on the basis of melam and a phosphorus-containing compound which can be prepared in an economic way in one single process step.
It has been found that this object is attained by preparing a phosphorus-containing salt of a melamine condensation product and a phosphorus-containing acid while using a monobasic phosphorus-containing acid as the phosphorus-containing acid. Melam is preferably used as the melamine condensation product.
Monobasic phosphorus-containing acids that are applicable in the present invention are compounds that contain at least a phosphoric acid, phosphonic acid or phosphinic acid group possessing only one acid equivalent.
Examples of phosphoric acid, phosphonic acid or phosphinic acid groups that possess only one acid equivalent are phosphate ester groups that can be represented by the general formula (I), alkyl phosphonic acid esters that can be represented by the general formula (II) and phosphinic acids that can be represented by the general formula (III):
(R
1
O—)(R
2
O—)—P(═O)—OH (I)
(R
3
O—)R
4
P(═O)—OH, (II)
R
5
R
6
P(═O)—OH, (III)
in which R
1
up to and including R
6
represent substituted or non-substituted alkyl, aryl, cycloalkyl, aralkyl or alkaryl substituents.
Preferably compounds are used that contain groups according to formula (II) and/or formula (III). Examples of suitable phosphinic acids according to formula (III) are ethylmethylphosphinic acid, diethylphosphinic acid, diethylphosphinic acid, a substituted or non-substituted 1-hydroxydihydrophospholoxide, a substituted or non-substituted 1-hydroxyphospholane oxide and diphosphinic acids. Diphosphinic acids are compounds with two phosphinic acid groups. Examples of suitable phosphonic acid esters according to formula (II) are the methyl, ethyl and propyl ester of methylphosphonic acid.
The phosphorus-containing salt of the monobasic phosphorus-containing acid and the nitrogen-containing compound comprises at least 50-95 mol % of a melamine condensation product, in particular melam.
In EP-A-363,321 a melamine phosphonate or dimelamine phosphonate is described and applied as a flame retardant in polymer compositions. The disadvantage of these salts is that it contains melamine, which can sublime during processing into polymer compositions. The method of preparing these salts stated in EP-A-363,321 is not applicable to condensation products of melamine, such as melam, due to the poor solubility of these in water.
Applicant has also found that the preparation of the phosphorus-containing salt of a melamine condensation product, in particular melam, can be carried out simply by heating a triazine compound and the monobasic phosphorus-containing acid together to a temperature between 250 and 400° C., preferably between 280° C. and 350° C. Suitable triazine compounds are melamine, ammeline and ammelide or mixtures of these. Preferably melamine is used. Impurities such as urea, dicyanodiamide, guanidine and ureidomelamine can be present without objection.
The quantity of monobasic phosphorus-containing acid used amounts to 0.05-0.5 mole per mole of triazine compound. Preferably, 0.1-0.5 mole is used. The monobasic phosphorus-containing acid can also be used in the form of its ammonium or melamine salt. When its melamine salt is used, allowance shall be made for the possible participation of the melamine in a condensation reaction, for instance to melam. The quantity of triazine compound metered to the reactor can be reduced accordingly.
The reaction is carried out by heating a mixture comprising a triazine compound and a monobasic phosphorus-containing acid, or the melamine or ammonium salt of it, to around 250-350° C. Preferably the reaction is carried out between 280 and 320° C. Preferably the reaction is carried out in an almost horizontal stirred reactor. During the reaction ammonia is formed, which can be removed by purging the reactor with an inert gas such as for example nitrogen. Besides melam, whether or not in the form of a phosphorus-containing salt, also small quantities of other triazine condensation products, such as for example melem, melon and methon, whether or not in the form of a phosphorus-containing salt can be formed during the reaction. It is also possible for a small part of the monobasic phosphorus-containing acid to be converted to an anhydride compound.
If desired the phosphorus-containing salt of the melamine condensation product, in particular melam, can be treated further. This further treatment is preferably scrubbing with water so that a part of the melamine and/or other water-soluble components dissolve and are removed from the phosphorus-containing salt of the melamine condensation product.
Applicant has also found that the phosphorus-containing salt of melam according to the invention brings about flame retardancy of polymer compositions.
The polymer composition then comprises, besides the phosphorus-containing salt of the melamine condensation product, in particular melam, at least a polymer. In addition it can comprise reinforcing agents and/or fillers and/or compounds having a synergistic effect for the phosphorus-containing salt of melam can contain compounds and/or flame-retardant components other than those according to the invention. Also the usual additives can further be present, such as for example heat and UV stabilizers, release agents, flow-promoting agents, plasticisers, lubricants, dispersing agents, dyestuffs and/or pigments, in quantities that are generally applicable for these additives insofar as the properties are not adversely influenced.
Polymer compositions that can be made flame-retardant with the phosphorus-containing salt of melam, contain polymers that require heat-resistant flame retardants, such as for example polyamides, polyimides, polyesters, polyurethanes and mixtures and blends of these materials.
Examples of polyamides are polyamides and copolyamides which are derived from diamine and dicarboxylic acids and/or of amino carboxylic acids or the corresponding lactams, such as polyamide 4, polyamide 6, polyamide 6/6,4/6, partially aromatic (co)polyamides, for example polyamides based on an aromatic diamine and adipic acid; polyamides prepared from an alkylene diamine and iso-and/or terephthalic acid and copolyamides thereof, etc.
Examples of polyester are polyester, derived from dicarboxylic acids and dialcohols and/or from hydroxycarboxylic acids or the corresponding lactones such as polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane
Acquah Samuel A.
Ciba Specialty Chemicals Corporation
Stevenson Tyler A.
LandOfFree
Salt of a melamine condensation product and a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Salt of a melamine condensation product and a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Salt of a melamine condensation product and a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3206976