A composition comprising a heat transfer portion and a lubricating portion, wherein the lubricating portion comprises one or more compounds according to formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br and I; Y is independently selected from the group consisting of F, Cl, Br and I; Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.PCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, polyalkylene glycol and polyolester; n is an integer from 2 to 250; m is an integer from 0 to 3; and p is an integer from 0 to 9.

The invention relates to mixtures of at least one diphosphinic acid of the formula (I)

##STR00001## in which R.sup.1, R.sup.2 are the same or different and are each independently H, C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene, C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II)

##STR00002## in which R.sup.3, R.sup.4 are the same or different and are each independently C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl and/or C.sub.7-C.sub.18-alkylaryl.

The invention also relates to a process for preparing these mixtures and to the use thereof.

The invention relates to mixtures of at least one diphosphinic acid of the formula (I)

##STR00001## in which R.sup.1, R.sup.2 are the same or different and are each independently H, C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene, C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II)

##STR00002## in which R.sup.3, R.sup.4 are the same or different and are each independently C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl and/or C.sub.7-C.sub.18-alkylaryl.

The invention also relates to a process for preparing these mixtures and to the use thereof.

The present invention refers to a flame retardant comprising a complex formed by phosphine oxide and transition metal salt, wherein has good flame retardant property. The present invention also refers to a composite flame retardant and flame retardant antistatic composition, wherein composite flame retardant comprise the flame retardant and the inorganic flame retardant component as described above, which has an enhanced flame retardant effect; said flame retardant antistatic composition, comprising above described flame retardant or composite flame retardant and carbon nanofiber antistatic agent, wherein carbon nanofiber antistatic agent could have interaction with flame retardant, effectively reducing the amount of flame retardant, and the combination with the flame retardant without the adverse effect of each other which result in negative performance of each other, does not influence the subsequent foaming process and the foam structure and physical properties. The present invention also further refers to a flame resistant method, which adds the abovementioned flame retardant, composite flame retardant or flame retardant antistatic composition into the material, so that said material has flame retardance or flame retardance and antistatic, and has excellent mechanical properties.

The present invention refers to a flame retardant comprising a complex formed by phosphine oxide and transition metal salt, wherein has good flame retardant property. The present invention also refers to a composite flame retardant and flame retardant antistatic composition, wherein composite flame retardant comprise the flame retardant and the inorganic flame retardant component as described above, which has an enhanced flame retardant effect; said flame retardant antistatic composition, comprising above described flame retardant or composite flame retardant and carbon nanofiber antistatic agent, wherein carbon nanofiber antistatic agent could have interaction with flame retardant, effectively reducing the amount of flame retardant, and the combination with the flame retardant without the adverse effect of each other which result in negative performance of each other, does not influence the subsequent foaming process and the foam structure and physical properties. The present invention also further refers to a flame resistant method, which adds the abovementioned flame retardant, composite flame retardant or flame retardant antistatic composition into the material, so that said material has flame retardance or flame retardance and antistatic, and has excellent mechanical properties.

The present provides a process for preparing dialkyl phosphinate, comprising: (1) firstly adding 0-99% of the total weight of phosphinic acids and/or salts thereof and a solvent into a reaction kettle; (2) in the reaction kettle in the presence of alkene and initiator, continuously adding 1-100% of the total weight of the phosphinic acids and/or salts thereof into the reaction system, during the addition process, when the mole contents of monoalkyl phosphinic acids and/or salts thereof account for 10% or less of the total molar contents of phosphorus in the reaction system, stopping adding the phosphinic acids and/or salts thereof. Also providing a dialkyl phosphinate flame retardant prepared by above preparation process.

The present provides a process for preparing dialkyl phosphinate, comprising: (1) firstly adding 0-99% of the total weight of phosphinic acids and/or salts thereof and a solvent into a reaction kettle; (2) in the reaction kettle in the presence of alkene and initiator, continuously adding 1-100% of the total weight of the phosphinic acids and/or salts thereof into the reaction system, during the addition process, when the mole contents of monoalkyl phosphinic acids and/or salts thereof account for 10% or less of the total molar contents of phosphorus in the reaction system, stopping adding the phosphinic acids and/or salts thereof. Also providing a dialkyl phosphinate flame retardant prepared by above preparation process.

A flame retardant composition according to the present invention is a phosphate-based flame retardant including a (poly)phosphate, in which F and N satisfy 8.0×10.sup.−4≤F/N≤20.0 and F≤21.0, assuming that F (ppm) is a content of elemental iron and N (ppm) is a content of elemental sodium in the flame retardant composition as measured in accordance with the following procedure.

A flame retardant composition according to the present invention is a phosphate-based flame retardant including a (poly)phosphate, in which F and N satisfy 8.0×10.sup.−4≤F/N≤20.0 and F≤21.0, assuming that F (ppm) is a content of elemental iron and N (ppm) is a content of elemental sodium in the flame retardant composition as measured in accordance with the following procedure.

The present invention relates to a process for producing flame-retarded polyurethane foams, in particular flexible polyurethane foams, using halogen-free flame retardants, wherein the resulting flame-retarded polyurethane foams exhibit low emission values coupled with good mechanical properties. The present invention further relates to halogen-free flame retardants.