Patent Application
20080064852
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawing, in which:
The invention is directed to adhesive compositions and methods of making adhesive compositions which can include ingredients set forth below. As will be evident to those of ordinary skill in the art, substitutions, omissions and additions will be possible in order to provide adhesives with customized selected properties.
Recent advances in agro-genetic engineering and natural fiber development offer significant opportunities for new, improved green raw materials from renewable resources that are biocompatible and biodegradable thereby enhancing global sustainability. Examples of such materials include cellophane (cellulose based), cellulose derivatives such as cellulose esters, engineered wood products, biofiber composites, polylactic acid (PLA) Polymer from corn, starch foams, soybean based biodiesel and lubricants.
Utilization of the free energy of sunlight to grow materials by photosynthesis helps remove global warming gases such as CO2 and reduces the dependence and use of depleting fossil fuels.
Preferred ingredients, preferred percentages of components in accordance with preferred embodiments of the invention are set forth in the Table 1 below:
The drying oil component can be included, about 5 to 40%, preferably 10 to 35%, more preferably about 15% to 30%, by weight of the total composition. The drying oil component can help to achieve the desired viscosity. It can also serve as a plasticizer and solvent to incorporate some of the solid ingredients.
Adhesives in accordance with the invention can also include tackifying rosins, particularly rosins having a softening point in the range of 70° C. to 140° C. Wood and gum rosins are examples of such rosins. The rosins are selected to give the cured adhesive the desired amount of cured strength. Appropriate selection of rosins also affects the uncured strength (initial shear strength) of the adhesive, often referred to as green strength. For example, if the adhesive is used as flooring adhesive, it is desirable that the uncured adhesive maintain the applied flooring in place with reasonable security so that tiles, for example, can be aligned properly and so that minor bumps and nudges do not require reseating and realignment of the flooring materials.
It has been determined that the cured strength and green strength of the adhesive can be related to the softening points of the resin material. As used herein, softening point will refer to the temperature at which viscous flow of a material that does not have a definite melting point changes to plastic flow.
Rosins in accordance with preferred embodiments of the invention generally have softening points between 70° C. and 140° C. By mixing rosins with different softening points, advantageous characteristics of each rosin can be realized.
A plasticizer or fluidizing agent from renewable sources, such as hydrogen oxide, can also be included, advantageously in the range of 10 to 45% by weight, advantageously 20 to 35%. The plasticizer provides tack and adhesion properties to help bind the components to each other as well as to the surface of the area under construction.
Surfactants, such as 6 to 10 mole ethoxylates of nonylphenols can be included, advantageously in the range of less than 5% by weight, advantageously 0.5 to 1.5%.
It can also be advantageous to include anti-foaming agents, in particular, non-silicon anti-foaming agents. These are advantageously included at less than about 0.5 weight percent, preferably 0.05 to 0.10 weight percent.
Adhesives in accordance with the invention can also advantageously include polymers derived from plant and animal renewable sources, particularly those having carboxyl, acrylic, methacrylate, epoxide functionality, such as acrylated epoxidized soybean oil polymers (AESO), maleinized soybean oil monoglyceride (SOMG), soy proteins, acrylated oleic methyl ester (AOME), polylactic acid (PLA), to provide enhanced adhesive properties. The polymers can be advantageously included between 1 to 80 weight percent, preferably 10 to 60 weight percent.
Compositions in accordance with the invention can also advantageously include fugitive alkali agents, such as ammonia, monomethanol amine (MEA) and triethanolamine (TEA). This alkali agent can be useful to adjust the pH. The invention can include up to 2%, preferably 0.1 to 1% of fugitive alkali agent.
Adhesive compositions in accordance with the invention can also include up to 2%, preferably 0.1 to 1% dispersing agents, such as salts of polyacrylic acids and dryers, in particular napthanates of metals, such as cobalt, calcium, zirconium and manganese. The dispersing agent can also include phosphates, such as tetrasodium pyrophosphate (TSPP). The dryers should be included in an effective amount to catalyze the drying speed of the drying oil to a desired rate. The precise amount will depend on both the desired speed of cure and the particular composition of the adhesive.
Adhesive compositions in accordance with the invention can also include effective amounts of fillers, such as calcium carbonate, kaolin clay, mica powder, talc and so forth. Fillers should generally represent less than 50% of the composition, preferable in the range of 20-40% of the composition. If too much filler is included the cohesive strength of the product can be reduced. If too little filler is included, the solids content will be too low for many applications.
A non-limiting example composition is below listed in Table 2, including a preferred process of making such example composition.
Using the example adhesive set forth in Table 2, shear strengths of traditional fossil fuel-based adhesives and bio-source based adhesives in accordance with the invention are recorded at various times and temperatures. The results are recorded in
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and, since certain changes may be made in carrying out the above method and in the compositions set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Particularly it is to be understood that in said claims, ingredients or compounds recited in the singular are intended to include compatible mixtures of such ingredients wherever the sense permits.
