Esterified acids for use in polymeric materials

#The present invention relates generally to polymeric materials, particularly to polymeric materials including an acid ester component to impart foam-in-place capability, improved flame retardancy characteristics, and/or curing capability which can be employed in a number of applications, such as in structural reinforcements and/or baffles for use in transportation vehicles.

#In the transportation and construction industries, epoxy-based adhesives and foams are frequently used to provide structural support, sealing, and sound attenuation. For curing and expansion of such adhesives and foams, the addition of separate curing agents and blowing agents are typically required, adding expense and time for manufacture. Fire retardancy is also often desired, requiring additional agents for imparting the same.

#Polymers having at least one epoxide group have been described in U.S. Pat. Nos. 5,115,075; 4,438,254; 6,011,111; and WO 98/14498 (see e.g., pages 3-8) along with illustrative synthesis conditions, all incorporated by reference herein (see also U.S. Pat. Nos. 3,317,471 and 4,647,648, also incorporated by reference herein). Examples of such materials also can be found, without limitation at paragraphs 15-25 of Published U.S. Patent Application No. 20070270515 (Chmielewski et al), incorporated by reference for all purposes.

#This application claims the benefit of the filing date of U.S. Provisional Application Ser. Nos. 62/135,337, filed on Mar. 19, 2015; and 62/208,236, filed on Aug. 21, 2015, the contents of these applications being hereby incorporated by reference for all purposes.

#The present teachings contemplate the use of an acid ester material in combination with epoxy. The method may include a step of providing a first amount of esterified reaction product of a phosphoric acid and an epoxide. The esterified reaction product may be further reacted an epoxy resin to form a foamable, cured and/or flame resistant epoxy, which may be a thermoplastic epoxy. For example, the resulting epoxy may be a polymer that includes an epoxide functionality and includes at least one phosphorus atom. The resulting polymer may have a weight average molecular weight of at least about 10,000 daltons (e.g., as determined by titration). The resulting polymer reaction product of the teachings may thus be capable of exhibiting flame retardancy and/or foamable characteristics. For example, it may meet one or more of the requirements for demonstrating flame retardancy (e.g., to meet vertical burn and/or smoke density requirements (or some other requirement) as set forth in 14 C.F.R. § 25.853 and 14 C.F.R. § 25.856 (the United States Code of Federal Regulations for compartment interiors, including but not limited to 14 C.F.R. § 25.853(a), and the referenced Appendix F and procedures referenced therein), all of which are incorporated by reference for all purposes).

#The present teachings provide for utilizing an acid ester as a replacement for an acid in creating epoxy-based materials capable of foaming-in-place and/or curing. More particularly, the composition of the present invention has two main components: (1) a resin, preferably a liquid resin or epoxy resin; and (2) an acid ester that is capable of initiating polymerization of the resin. The resin component may be further defined as having a core encapsulated by a polymer or other heat fusable substance such as a substrate to create a shell or skin. The core may consist of a salt, which may be a metal salt, and may be a metal carbonate encapsulated by a hydrocarbon, such as a polymer or wax. Although the core within the thermoplastic or the shell itself may further comprise an optional blowing agent formulated with the resin component, it is possible that no additional curing agent or blowing agent is required in the present invention. In this regard, it is contemplated that the acid ester component, when combined with the resin component (having the encapsulated core), initiates the curing process and gas generation. In addition, the acid ester may act as a fast curing agent while also maintaining the ability to fully cure thicker bondline materials. As an example, typical epoxy curing agents such as acrylates are only able to cure relatively thin sections of material (e.g., 3 mm or less), whereas the use of an acid ester curing agent allows for cure of thicker sections (e.g., 5 mm, 6 mm or greater).