US 2011 0129.683A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0129683 A1 Ahn et al. (43) Pub. Date: Jun. 2, 2011 (54) RADICAL POLYMERIZABLE COMPOSITION Publication Classification (51) Int. Cl. (76) Inventors: Dongchan Ahn, Midland, MI (US); f 275" 3883 Gang Lu, Midland, MI (US) C09D 133/14 (2006.015 BOSD 3/02 (2006.01) (21) Appl. No.: 13/056,199 (52) U.S. Cl. ......... 428/522:526/194; 526/198: 524/558: 524/547; 427/385.5 (22) PCT Filed: Jul. 27, 2009 (57) ABSTRACT A radical polymerizable composition includes a radical poly merizable compound and an organoborane-azole complex. (86). PCT No.: PCT/USO9/S1829 The organoborane-azole complex includes anazole having at least two nitrogenatoms wherein at least one nitrogenatom is S371 (c)(1), an spnitrogen atom and is substituted. A method of forming (2), (4) Date: Jan. 27, 2011 the composition includes the step of combining the radical polymerizable compound and the organoborane-azole com O O plex to form the composition. The method also includes the (30) Foreign Application Priority Data step of polymerizing the composition. A composite article which includes a Substrate and a cured composition disposed Jul. 28, 2008 (US) ................................... 61/O84173 on the Substrate is also provided. The cured composition is Jul. 27, 2009 (US) ................. PCT/US2009/051829 formed from polymerization of the composition. US 2011/0129683 A1 Jun. 2, 2011 RADICAL POLYMERIZABLE COMPOSITION complexes typically reacts at room temperature, via Michael addition reactions, with acrylic monomers or with other FIELD OF THE INVENTION impurities to prematurely initiate polymerization. This reduces shelflife and minimizes the efficiency, predictability, 0001. The present invention relates to a radical polymer and reproducibility of polymerization reactions. izable composition. More specifically, the radical polymeriZ 0007. One particular reference that focuses onborontech able composition includes a radical polymerizable compound nology, WO 01/44311 to Sonnenschein, et al., discloses and an organoborane-azole complex including a Substituted borane-imidazoline complexes that include “imine' bonds. azole. The present invention also relates to a method of form As is known in the art, imidazoline complexes that include ing the radical polymerizable composition. “imine' bonds are not aromatic and are quite different than imidazole complexes which have at least two double bonds DESCRIPTION OF THE RELATED ART and are aromatic. In a typographical error that appears at least 0002 Countless radical polymerizable compositions are on page 29 (Table 1. Example 65), Sonnenschein discloses known in the art and have been investigated for use in many “2-methyl-2-imidazole.” This compound cannot exist. industrial processes. Radical polymerization is a widely used Instead, this name is presumably referring to “2-methyl-2- process for production of a range of plastic goods due to its imidazoline' which only has a single carbon-nitrogen double Versatility and robustness. Radical polymerization is typi bond. In a subsequent U.S. Pat. No. 6,706,831, this error is cally used to produce large commodity and specialty plastics corrected to read “2-methyl-2-imidazoline in Table 1, including polystyrene and polymethylmethacrylate and also Example 65. to produce adhesives, sealants, inks, paints, coatings, and 0008. Additionally, the 831 patent discloses a pyrazole composite articles. complex with TBB and an imidazole complex, both of which 0003 Conventional radical polymerization systems are are predicted to be unstable or marginally unstable based typically azo-based or peroxide-based and utilize azobi upon theoretical binding energy calculations of 10.2 and 11.1 sisobutyronitrile and benzoyl peroxide, respectively. These kcal/mol, respectively. Both of these calculations are near the systems can be activated using heat or ultraviolet (UV) radia stability threshold of 11. Further, the 831 patent discloses an tion. In heat activated systems, high temperatures are organoboraneamine complex with an aminofunctional azole employed and reaction times typically average greater than (3-amino pyrazole) which is calculated to have a theoretical 12 hours thereby raising production costs and times and binding energy of 13.2 kcal/mol, Suggesting that its stability increasing energy expenditure. If these high temperatures are is enhanced by a primary amino group. However, when this not used, limited storage stability of the radical polymerizable type of azole is used with certain monomers, such as acrylic compositions at ambient temperatures can result. Also, the monomers, unfavorable Michael additions may occurthereby peroxide-based systems are easily inhibited in the presence of leading to poor results. atmospheric oxygen leading to uncured or poorly cured prod 0009. Further, the 831 patent discloses that, in certain ucts having wet surfaces. Undesirable decomposition by industrial processes. Such as those involving low Surface products may also be generated. Thus, these types of systems energy olefins such as polyethylene, polypropylene, and typically require use of an inert (oxygen-free) atmosphere, polytetrafluoroethylene, it is difficult to develop adhesive thereby further raising production costs and complexities. compositions that exhibit adequate bonding strength. Typical 0004. In UV radiation activated systems, costly photoini commercially available adhesives that are used for these tiators are typically used which also raises production costs materials require time consuming or expensive pre-treatment and times and increases energy expenditure. Additionally, steps such as corona treatment, flame treatment, application UV radiation systems are not preferred for use in bulk poly of primers, and the like. These pre-treatment steps result in merizations where UV transmission is limited. increased production costs, times, and complexity. 0005 One specific means of curing compositions using 0010. Therefore, there remains an opportunity to form a radical polymerization includes use of boron compounds, e.g. polymerizable composition that includes components that are with an organo-functional boron compound. Organoboron chemically stable in monomer Solutions such as acrylate compounds initiate free radical polymerization and promote functional monomer Solutions and that do not readily react adhesion to low Surface energy Substrates due to an ability to with amines or impurities at room temperature, but can be generate radicals to polymerize radical polymerizable com activated rapidly by deblocking to initiate polymerization pounds. However, oxidation of organoboron compounds with when desired. There are also remains an opportunity to form molecular oxygen forms energetic peroxides which are exo a polymerizable composition that can be polymerized effi thermic and can be pyrophoric if not carefully controlled. Due ciently, predictably, and reproducibly. to this reactivity, the organoboron compounds have been sta bilized with blocking agents that dissociate under controlled SUMMARY OF THE INVENTION AND conditions to release the organoboron compounds and initiate ADVANTAGES free radical formation. The blocking agents render the orga 0011. The present invention provides a radical polymeriz noboron compounds less Susceptible to oxygen insertion and able composition that includes a radical polymerizable com radical initiation. pound and an organoborane-azole complex. The organobo 0006. One type of blocking agent includes amines which, rane-azole complex includes an azole having at least two when reacted with the organoboron compounds, form orga nitrogenatoms wherein at least one of the nitrogenatoms is an noborane-amine complexes. Although functional, the orga sp. nitrogen atom and is substituted. The present invention noborane-amine complexes are not stable for extended peri also provides a method of forming the radical polymerizable ods in acrylate functional monomer Solutions, such as those composition. The method includes the step of combining the commonly used in adhesives. Ifused in these types of mono radical polymerizable compound and the organoborane-azole mer Solutions, the amine portion of the organoborane-amine complex to form the radical polymerizable composition. The US 2011/0129683 A1 Jun. 2, 2011 method also includes the step of polymerizing the radical may be used to impart a desired combination of bulk and polymerizable composition. The present invention also pro Surface properties such as cure rate, modulus, and adhesion, vides a composite article including a Substrate and a cured to the composition. In another embodiment, the radical poly composition disposed on the Substrate. The cured composi merizable compound includes a silicon compound and an tion is formed from polymerization of the radical polymeriz organic compound. able composition. 0017. In yet another embodiment, the radical polymeriz 0012. The organoborane-azole complex is chemically able compound is substantially free of silicon atoms (Si). That stable both in air and in monomer Solutions such as acrylate is, in one embodiment, the composition is Substantially free functional monomer Solutions and does not readily react with of radical polymerizable compounds that include one or more acrylic monomers or reaction impurities at room temperature silicon (Si) atoms. It is to be understood that the terminology via Michael additions. This stability reduces a chance that “substantially free” refers to a concentration