US 9,249,251 B2  3  4  greater than 3.8 to 11, heating the reaction mixture to a tem› perature of about 120°  C. to about 165°  C. and substantially  completing reaction of arylhydroxy monomer in the reaction  mixture.  In yet another aspect of this invention, the triazine-phenol- aldehyde condensate as described herein, either alone or in  admixture with another epoxy curing agent and/or another  fire-retardant, may be used as a fire-retardant curing agent for  epoxy resins.  In another aspect, a prepreg of a porous substrate is pro- vided and includes a curable epoxy resin and a condensate of  a reaction mixture a triazine monomer, an arylhydroxy mono› mer, an aldehyde monomer and an acid catalyst having a pKa  of greater than 3.8 as the curing agent alone or in combination  with another curing agent.  In another aspect, a laminate is provided including one or  more prepregs impregnated with an epoxy resin and a con› densate of a reaction mixture a triazine monomer, a phenol  monomer, an aldehyde monomer and an acid catalyst having  a pKa of greater than 3.8 alone or together with another curing  agent wherein the epoxy resin composition is cured.  In another aspect, a glycidylated triazine-phenol-aldehyde  condensate is provided in a reaction mixture, wherein the  condensate prior to glycidylation is a reaction mixture com› prising a triazine monomer, a phenol monomer, an aldehyde  monomer and an acid catalyst having a pKa value range from  greater than 3.8, and comprises up to about 28 wt. % of  nitrogen, a melt viscosity of less than 3,000 cps at 175°  C.,  and a solubility of up to about 80 wt. % solids dissolved for  120 hours or greater in one or more organic solvents having  one or more functionalities selected from the group consist› ing of an ether functionality, a ketone functionality, an alcohol  functionality, an ester functionality,  and combinations  thereof.  In another aspect, a composition suitable for electronic  applications is provided and includes an epoxy resin wherein  for each 100 parts of epoxy resin the composition contains  about 0-30 parts of a phenolic-formaldehyde novolac, option› ally an epoxy curing accelerator, and about 30 to 60 parts of  a triazine-phenol-aldehyde condensate in a reaction mixture  comprising a triazine monomer, a phenol monomer, an alde› hyde monomer, and an acid catalyst having a pKa value range  from greater than 3.8 to about 11, wherein the triazine-phe› nol-aldehyde condensate and comprises up to about 28 wt.%  of nitrogen, a melt viscosity ofless than 3,000 cps at 175°  C.,  and a solubility of up to at least about 80 wt. % solids dis› solved for 120 hours or greater in one or more organic sol› vents having one or more functionalities selected from the  group consisting of an ether functionality, a ketone function› ality, an alcohol functionality, an ester functionality, and com› binations thereof.  In another aspect, a method for the preparation of a con› densate product is provided and includes charging to a reac› tion vessel to form a reaction mixture of a triazine monomer,  about 3 to about 30 moles of a phenol monomer for each mole  of triazine, an acid catalyst having a pKa from 6 to about 11,  and from about 1 to about 6 moles of an aldehyde monomer  for each mole oftriazine monomer, heating the reaction mix› ture at a temperature from about 165°  C. to about 180°  C.,  removing the phenol monomer and any water from the reac- tion mixture, and steam sparging the reaction mixture.  In another aspect, a method for the preparation of conden› sate product is provided and includes charging to a reaction  vessel to form a reaction mixture of an aldehyde modified  triazine monomer and about 3 to about 30 moles of a phenol  monomer for each mole of aldehyde modified triazine mono› mer and heating the reaction mixture to a temperature of  The processes for forming the condensates as described  herein also allow for the production of the condensates in  large reaction vessels with improved control over melt vis› cosity than the prior methods to produce similar condensates.  In one aspect, the triazine-arylhydroxy-aldehyde conden› sate is formed from a reaction mixture of a triazine monomer,  an arylhydroxy monomer, and an aldehyde monomer, and an  acid catalyst having a pKa of greater than 3.8, which are  described as follows. In one embodiment, the triazine mono› mer may include an aldehyde functional group, such as an  aldehyde modified triazine monomer. The aldehyde modified  In comparison, most of the condensates from prior art  processes typically dissolve only up to 40 wt.% (solids) and  in selected cases roughly about 60 wt. % in common solvents  such as MEK.  In particular, the triazine-arylhydroxy-aldehyde conden› sates described herein were observed to provide an improved  solubility by dissolving completely in one or more organic  solvents having one or more functionalities selected from the  group of an ether functionality, a ketone functionality, an  alcohol functionality, an ester functionality, and combina› tions thereof, of which a ketone functionality solvent, such as  methyl ethyl ketone (MEK) may be used. The condensates  formed as described herein were observed to have a solubility  from less than 10 wt.% solids up to 80 wt.% solids, such as  from about 33 wt.% solids to about 75 wt.% solids, to give a  transparent solution (no turbidity) for 120 hours or greater.  Other condensates formed by the processes described herein  were observed to have a solubility up to 80 wt.% solids (and  sometimes greater) for at least 500 hours.  Additionally, it was surprisingly and unexpectedly discov› ered that the triazine-arylhydroxy-aldehyde condensates  formed by the components and processes described herein  have improved solubility over those in the prior art. The  triazine-arylhydroxy-aldehyde condensates described herein  were observed to stay dissolved in an organic solvent at up to  80 wt. % solids (or higher) for at least 120 hours (5 days)  before cloudiness set in, or precipitation, in the form of a  white circle at the bottom of the vial, began.  Through the choice of acid catalysts with a pKa value of  greater than 3.8, the triazine-arylhydroxy-aldehyde conden› sates exhibit a viscosity range of3000 cps or less at 175°  C.,  such as from about 200 cps to about 2000 cps, and contain  from about 8 wt. % to about 28 wt. % nitrogen content, for  example, from greater than about 10 wt. % to about 24 wt. %  nitrogen content. The triazine-arylhydroxy-aldehyde con› densates described herein may be substantially free of water  as further described herein and may have about 2 wt.% or less  of free arylhydroxy monomer.  In one aspect, the present invention provides for a triazine› ary lhydroxy-aldehyde condensate, such as a triazine-phenol› aldehyde (T-P-A or TPA) condensate and processes for the  preparation of the triazine-arylhydroxy-aldehyde conden- sate. The triazine-arylhydroxy-aldehyde condensate may be  formed from a reaction mixture of a triazine monomer, an  arylhydroxy monomer, and an aldehyde monomer, and an  acid catalyst having a pKa of greater than 3.8.  Embodiments of the invention are directed to condensates,  methods for making the condensates, and application of the  condensates in epoxy resins, prepregs of porous substrates,  and laminates.  about 130°  C. to about 180°  C. and substantially completing  reaction of phenol monomer in the reaction mixture.  DETAILED DESCRIPTION OF THE INVENTION 