Patent Application
20070244240
A polyvinyl alcohol-stabilized dichlorobutadiene/α-bromoacrylonitrile copolymer latex is prepared with the following ingredients (PHM=parts per hundred parts monomer):
The polyvinyl alcohol, methanol, Na2S2O5 and 856 grams of water are added to a 3 L flask equipped with stirring, N2, heat and a condenser. The mixture is heated to 50° C., after which the two monomers and the (NH4)2S2O8 dissolved in the remaining water are added over a 1 hour period. The resulting latex is vacuumed-stripped for 1 hour at 80 mmHg and 50° C. to remove the methanol. The latex has a solids content of 35% and a viscosity of 300 centipoise.
A master batch is prepared by milling the following ingredients for 2-3 hours in a ceramic bead mill to achieve desired particle size:
(a)MARASPERSE CBOS4 (American Can Company)
110.0 g of the resulting master batch is then added to 188.6 g of the latex described above having a solids level of 35% in water. To this mixture 2.0 grams of 50% solids DAPRO W-77 is added along with 32.73 g of water. The resulting adhesive comprises 30% solids. Ammonium hydroxide is added to adjust the pH to approximately 7. This would represent process for preparing Sample A identified below.
The following formulations are prepared as outlined above with DAPRO W-77, DNB, and optionally gamma POM added to the adhesive formulation.
A conventional aqueous primer is sprayed onto zinc phosphatized steel coupons at a film thickness of 0.30 mils. The adhesive compositions were then prepared as below and then spray applied to the primed metal coupons at a film thickness of 0.70 mils. The coated coupons were then bonded to a natural rubber substrate by compression molding the rubber on to the coupons at 340° F. Different natural rubber compounds identified as Rubber A, Rubber B and Rubber C were tested.
Bonded parts are pulled to destruction according to ASTM Test D429—Method B. Parts are tested in peel with a peel angle of 45 degrees. The test is conducted at room temperature with a test speed of 2.0 inches per minute. After the bonded part fails, the percent rubber retention on the adhesive coated area of the part is measured.
Bonded parts are pulled to destruction immediately upon removal from the mold as close to 340° F. as possible. After the bonded part fails, the percent rubber retention on the adhesive coated area of the part is measured.
Boiling water tested parts are pulled at a 90 degree angle with a 2 Kg weight applying a constant stress. After 24-hour test is complete pliers are used to tear remaining rubber from tested part. After the bonded part fails, the percent rubber retention on the adhesive coated area of the part is measured.
The results of these tests illustrate that the adhesive composition comprising only zinc oxide performs as well as compounds containing gamma POM (polyoxymethylene) for boiling water resistance.
Although the present invention has been described with reference to particular embodiments, it should be recognized that these embodiments are merely illustrative of the principles of the present invention. Those of ordinary skill in the art will appreciate that the apparatus and methods of the present invention may be constructed and implemented in other ways and embodiments. Accordingly, the description herein should not be read as limiting the present invention, as other embodiments also fall within the scope of the present invention.
This application claims the benefit of, and incorporates by reference, U.S. Provisional Patent Application No. 60/791,825 filed Apr. 13, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60791825 | Apr 2006 | US |
