Method for Initiating Polymerization of Cyanaocrylate Monomers Blends thereof to give Reproducible and Predetermined Gel/Transition Time Characteristics

United States Patent [191 [11] 3,903,055 Buck [45] Sept. 2, 1975 3,347,798 10/1967 B361‘ Ct al. ........................ .. 252/448 POLYMERIZATION OF CYANOACRYLATE 3,594,358 7/1971 Moberly ........................... .. 260/92.8 MONOMERS AND COMONOMER BLENDS THEREOF TO GIVE REPRODUCIBLE AND PREDETERMINED GEL/TRANSITION TIME P”".'“”-" E*'“'"’f’”‘“~'°S°F?h L S°“°fe' CHARACTERISTICS Assistant Exammer——.Maria S. Tungol [75] Inventor: Carl J. Buck, Berkeley Heights, NJ. [73] Assignee: Johnson & Johnson, New Brunswick, N..l. [57] ABSTRACT [22] Filed: Dec. 5, 1973 [21] Appl No _ 422 047 A method is disclosed for initiating the polymerization of small amounts of relatively sensitive liquid mono- Related US, Application Data mer compositions, comprising esters of cyanoacrylic [63] Cominuation_in_pan of Ser_ No_ 317,497’ Dec 21_ acid, by means of a polymerization catalyzing particle 1972_ abandoned_ adapted to be added to the monomer composition and then separated from the same prior to gelation of the [52] U_s_ C]___ ____ __ 260/73_4 N; 106/35 monomer. The catalyzing particle may be in the form [51] Int. Cl. ................ .. C08f 3/74; CO8g 33/02 of a discrete particle such as beads. chips. or the like, [58] Field of Search .............................. .. 260/78.4 N or in the form of a rod sufficiently long so that the same can be used to simultaneously stir and activate [56] References Cited the monomer- UNITED STATES PATENTS 3,260,637 7/1966 von Bramer et al. ............ .. 260/78.4 9 Claims, N0 Drawings .—.-.H. ._ ._,,, , 5000 sec. Piperidine Instantaneous N-Mcthylpipcridine Instantaneous Pyridine Instantaneous 3.5-Dimethylpyridine Instantaneous n-Propylamine Instantaneous N.N,N'.N'-TetramethyIethylene- diamine Instantaneous 1 .1 ,4,4-Tetramethyl-1 .4- hutancdiamine Instantaneous Instantaneous Triethylamine ,8 EXAMPLE I1 . Loading of Less than Maximum Catalyst Concentrations on Molecular Sieves A weighed quantity of molecular sieve beads is added to reagent grade acetone as the diluent. After the exo- therm has subsided, a weighed quantity of DMPT is added and the beads and solution concentrated slowly on a rotating evaporator to remove the solvent. Evapo- ration in vacuo at the ambient temperature is contin- ued until the beads assume a dry surface appearance and are of constant weight. The percent by weight of DMPT impregnated in the beads can be estimated from the weight increase of the beads or determined more accurately by volumetric titration with standardized hydrochloric acid as in the procedure described in Ex- ample I. 10 15 20 Examples of the results obtained through both these proocedures are set forth in the following Table III. 25 TABLE III Quantity of Material Bead Weight Nominal Pore Charged After DMPT "/z DMPT Type Beads Diameter, °A Beads DMPT Treatment ‘/1 Add—On by Assay 8 X 12 mesh 4 l6.13g 0.33g l6.62g 2.95 1.7-1.9 8 x 12 mesh 4 l9.80g ().2()g 2l.8lg 9.2 8.8 8 X 12 mesh 4 6.62g excess 8.30g 20.7 20.0 8 X 12 mesh 10 6.00g excess 8.92g 32.7 24.6-27.6 4 X 8 mesh 10 l().55g excess l5.2lg 30.6 31.7 Two preferred procedures for impregnation of mo- lecular sieve beads with N,N-dimethyl-p-toluidine (DMPT) are shown in Examples I and II. EXAMPLE 1. Maximum Loadings of Catalyst on Molecular Sieves A weighed quantity of molecular sieve beads is cov- cred with neat N,N-dimethyl-p-toluidine and, after the exotherm has subsided, it is allowed to stand at room temperature for several hours or overnight in a sealed container. The contents are suction-filtered to recover unused DMPT catalyst, and the amine-saturated beads are blotted dry with absorbent paper towels to remove excess surface amine. The amine-uptake of the catalyst beads can be estimated from the percent weight gain of the beads. The actual amine content on the beads is de- termined by titration of a methanol extract of an accu- rately weighed quantity of treated beads with 0.1 N hyrochloric acid, using thymol blue (0.3%w in metha- nol) as indicator. Amine content is calculated from the following formula ml. titrants >< Normality X 13.52 % W DMPT: Sample weight, in grams lar To illustrate the reproducible gel times of this inven- tion, the following examples are set forth in Table IV below. These results are obtained in the following man- ner: Into an aluminum dish are added 5 drops (approx. 0.1 g) of the cyanoacrylate monomer. To this is added one DMPT-impregnated molecular sieve catalyst head. The bead is stirred gently with a glass rod in the pool of monomer for 30 seconds. The bead is then removed. The time, in seconds, is measured from the introduc- tion of the bead to the gelation point. TABLE IV 45 50 Gelation Time (seconds) for 55 "/1 DMPT l00‘7z Isobutyl in Bead 2-Cyanoacrylate (IBC) with ca 30 ppm S02 8.8% 347 4°A. 332 60 8 X 12 mesh 36] 276 372 15% 145 10°A. 134 8 X 12 mesh 145 167 65 24.6—27.6% 69 lO°A. 79 8 x 12 mesh 79 80 72 3,903,055 9 Generally, the individual pellet size of the molecular sieve material, based on the outer dimensions, e.g., di- ameter, suitably falls in the range of from about 56.6 to 0.523 mm3. This is equivalent to molecular sieve beads which have a size of from 4 to 16 mesh. The preferred molecular sieve beads have a size of from 6 to 10 mesh. As set forth above, a single bead having an 8 X 12 mesh size and impregnated with 25-30% by weight of DMPT and having a pore diameter of 10 Angstroms will be sufficient to catalyze 0.1 gram (approximately 5 drops) of monomer. For the most part this monomer to molecular sieve volume ratio will be linearly main- tained for larger quantities of monomer. Therefore, three bands of the same size, bearing the same amount of catalyst, would be used to catalyze 0.3 grams mono- mer. Yet, because monomers differ in quantity of in- hibitor they may contain it is difficult to precisely pre- scribe an exact number of pellets for catalyzing a given quantity of monomer. Therefore, a standardization procedure, as previously described, should preferably be used to determine the number of pellets which should be used to catalyze a given quantity of any par- ticular monomer. To minimize the number of catalyz- ing particles employed per unit volume of monomer, it is convenient to reduce inhibitor concentration to as low a level as possible while still retaining sufficient in- hibitor to impart a reasonable shelf-life to the mono- mer. Although, in the preferred practice, molecular sieves are used in preparing the catalyzing particle, as previ- ously indicated, the same can be in the form of a rod formed of wood. This is illustrated in the following Ex- ample Ill. EXAMPLE III Wood sticks (birch), measuring approximately 0.08 inch diameter X 6 inches length, are immersed in one end only in neat N,N-dimethyl-p-toluidine for 2 to 3 minutes. The sticks are then withdrawn and wiped dry on the surface with absorbent paper wipes. Five (5) drops of isobutyl 2-cyanoacrylate monomer are measured into a small polyethylene or aluminum container. The catalyst treated end of a single applica- tor stick is stirred gently in the pool of monomer for 30 seconds and then withdrawn. The liquid monomer started to gel, followed rapidly by polymerization into a hard transparent mass within 20 seconds after re- moval of the catalyzing particle (stick), or within 50 seconds from the time the monomer was first contacted with the catalyzing particle. , When the catalyzing sticks are impregnated with N,N-dimethyl-m-toluidine and used in the same fash- ion, the isobutyl 2-cyanoacrylate monomer started to gel, followed rapidly by polymerization into a hard mass, within 45 seconds after removal of the catalyst particle (stick). The process of the present invention, in which cata- lyzing particles are used for activating the cyanoac- rylate monomer, is not limited to a liquid system wherein the catalyzing particle is added to fluid mono- mer alone, but the same may be used for activating the cyanoacrylate monomer where the same is heavily filled with small discrete particles so as to have a paste- , like consistency, as where the same is used for highly- filled restoratives which may be used, for example, in the filling of tooth cavities. Where used with such paste-like consistency monomer-filler mixes, the cata- 10 15 20 25 30 35 40 45 50 55 60 65 := "510 lyzirig particle ‘is inserted‘ ‘into the ,‘ paste, the same mixed, the particle is then removed‘, and the activated paste is ready for use. Thisis illustrated in the following Example IV. EXAMPLE IV 1.70 g (85% w) of a silane treated quartz filler ( l5-20 microns, median particle size) are blended with 0.30 g (15% w) isobutyl 2-cyanoacrylate and stirred until a smooth pasty consistency is obtained. To this is added one molecular sieve catalyzing particle (4 X 8 mesh, about 30% w N,N-dimethyl-p-toluidine content). The catalyst particle is stirred in the filled cyanoac- rylate formulation for 60 seconds and then removed. The mass retains its pasty consistency for about 100 seconds after removal of the catalyst particles and then polymerizes rapidly into a hard composite. From the foregoing description, it is apparent that the objects of this invention are achieved in a new and novel manner. From the foregoing description it will be apparent to those skilled in the art that alternatives to the specific embodiments illustrated can be practiced within the spirit and scope of the present invention. The activated monomer, after removal of the catalyz- ing particle, may have numerous practical uses wherein advantage is taken of its ability to adhere to surfaces to which it is applied prior to gelation. For example, it can be used as a pit and fissure sealant wherein it is coated on the teeth to be protected and then strongly adheres to the same. It can also be used as an adhesive to ad- here surfaces together. In such cases, the activated monomer would be used to wet both surfaces to be ad- hered and the surfaces pressed together prior to gela- tion and polymerization. The monomer would then pol- ymerize in Contact with the surfaces to form a strong cyanoacrylate bond between the same. Such bonding may be used by an orthodontist in the application of brackets and the like. What is claimed is: 1. The method for the controlled anionic polymeri- zation of a liquid cyanoacrylate monomer within a pre- dictable time interval following initial contact of the monomer with a polymerization catalyst for the same, comprising admixing a catalyzing particle with said monomer, and then separating said catalyzing particle from said monomer prior to the gelation of said mono-' mer, said catalyzing particle comprising a surface po- rous carrier impregnated with an amine catalyst having a pK,, value of 9.2 to 6.0, of the group consisting of sec- ondary and tertiary aniline derivatives whereby gela- tion of said monomer followed by polymerization of the same to a hard mass occurs within a predicted time per- iod, thus providing a known period during which the catalyzed, but fluid, monomer can be applied to work- ing surfaces prior to polymerization. 2. A method according to claim 1 wherein the amine catalyst is selected from the group consisting of N-alkyl and N,N-dialkyl-substituted anilines and wherein the alkyl group contains 1 to 4 carbons. 3. A method of claim 2 wherein the amine is selected from the group consisting of N,N-dimethylaniline, N,N,2,4-tetramethylaniline, N,N,3,5- tetramethylaniline, N,N-dimethyl—o-toluidine, N,N-dimethyl-m-toluidine, and N,N-dimethyl-p- toluidine, N-methyl-N-phenylbenzylamine, and their corresponding N-ethyl and N,N-diethyl derivatives. rous carrier is in the form of a rod having a diameter of about 0.2 to 0.04 inches. 3,903,055 .11 4. A method of claim. 3. in which the amine is N,N-dimethyl-p-toluidine. 5. A method of claim 1 wherein the mohomer is a 2- cyanoacrylate ester selected from the group consisting of phenyl, cyclohexyl, and C, to C16 alkyl esters. 5 6. A method according to claim 3 in which the po- rous carrier is a molecular sieve bead having a particle sizeof about 4 to 16 mesh. 7. A method according to claim 3 in which the po- 10 8. The method of claim 1 wherein after separation of 15 20 25 30 35 40 45 50 55 60 12 said catalyzing particle and prior to gelation said mono- mer is coated on a surface and polymerizes while in contact with said surface. 9. The method of claim 1 wherein after separation of said catalyzing particle and prior to gelation of said monomer said monomer is placed on two separate sur- faced so as to wet the same with said monomer and said two wetted surfaces are brought and held together while said monomer wetting said surfaces gels and po- lymerizes. Patent No. Inventor (s) UNITED STATES PATENT OFFICE CERTHHCATE OF CORRECTHMN 3,903,055 1975 Datai September 2, Carl J. Buck . It is certified that error appears in the above—identified patent and that sa1d Letters Patent are hereby corrected as shown below: Column Column Column Column Column Column vcolumn 12, line 35, "0" should read -— p --. line 61, ”hyrochloric" should read -- hydrochloric --. at bottom of page, delete ”1ar”; line 21, ”proocedures” should read -— procedures —-{ line 14, “bands” should read -- beads --. line 37; "immersed in" should read -- immersed on --. line 7, “surfaced” should read -- surfaces --. Signed and Sealed this Twenty-fifth Day of January 1977 RUTH C. MASON Arresting Offiter C. MARSHALL DANN (‘ommissimrer nfPaten!: and Trademarks