Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-09-01
2001-05-08
Szekely, Peter (Department: 1714)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C052S698000, C523S176000, C524S533000, C524S560000
Reexamination Certificate
active
06228207
ABSTRACT:
TECHNICAL FIELD
This invention relates to a composition for anchoring materials in or to concrete or masonry. More particularly, this invention relates to a alkylacrylate ester/methacrylic acid copolymer composition for anchoring materials in or to concrete or masonry.
BACKGROUND OF THE INVENTION
Many applications require that a material be anchored in or to concrete or masonry. For example, anchor bolts are employed in various fields of engineering as strengthening or reinforcing members in rock formations, or concrete or masonry structural bodies. The bolts, which are typically metallic, are inserted into holes in the rock formations, or concrete or masonry structural bodies, and are fixed or anchored therein by means of an anchor composition. Typically, the anchor composition cures or hardens (polymerizes) to form a strong bond between the rock formation, or the concrete or masonry structural body and the bolt. In concrete and masonry, anchor bolts are used for reinforcement. Anchor bolts are also used for attaching objects to concrete or masonry. Objects that have been attached to concrete or masonry using anchor bolts include, but are not limited to, electrical conduits, panels, piping and wall sections. Adhesive anchors are preferred over mechanical anchors for anchoring in soft concrete or masonry because adhesive anchors place less stress on the concrete or masonry. As used herein, the term “masonry” shall include, but is not limited to, stone, brick, ceramic tile, cement tile, hollow concrete block and solid concrete block.
A useful anchor composition should be inexpensive, provide for a strong bond between the concrete or masonry and the material to be anchored to the concrete or masonry, be easy to dispense at the location of use and have a long storage shelf life. Some anchor compositions that have been used include compositions based on aromatic vinyl esters, aromatic polyesters and epoxies. These compositions can be expensive or may not provide the desired bond strength between the concrete or masonry and the material that is anchored in or to the concrete or masonry.
An example of the anchor compositions of the prior art is found in Japanese Patent Application Sho59-122762 (“JP '762”). Generally, JP '762 discloses an anchor composition comprising a monomer, a polymer soluble in the monomer, aggregate and a hardening agent. With respect to the monomer component, JP '762 discloses a broad range of compounds which include methacrylate esters. With respect to the polymer component, JP '762 discloses a similarly broad range of compounds which includes methacrylate esters and acrylic acid, and further discloses the use of copolymers. Moreover, JP '762 discloses a composition comprising 70 to 95% by weight of the monomer and 5 to 30% by weight of the polymer.
Notably, however, JP '762 fails to recognize the unexpected and surprising properties of fast cure time and pull out strength realized by the selection of a methacrylate ester monomer and a copolymer of a methacrylic ester and methacrylic acid in the formation of an anchor composition as shown herein. The unexpected and surprising results achieved by this particular combination is shown in certain of the examples set forth below in which significantly shorter cure times and greater pull out strengths are exhibited by the compositions of the present invention as compared to other compositions which fall within the scope of the broad disclosure of JP '762. As a result, the composition of the present invention represent a novel and unobvious advancement over the prior art.
SUMMARY OF THE INVENTION
The present invention provides a composition for anchoring materials in or to concrete or masonry that comprises from about 20% to about 90% by weight of the entire composition of a alkylacrylate ester monomer and an alkylacrylate ester/methacrylic acid copolymer; a free-radical catalyst; and a filler.
In a preferred embodiment, the present invention provides a composition for anchoring materials in or to concrete or masonry that is made by mixing a first composition and a second composition. The first composition comprises from about 20% to about 90% by weight of the entire composition of a methacrylate ester monomer and methacrylate ester/methacrylic acid copolymer; and a filler. The second composition comprises a free-radical catalyst.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides an anchor composition for anchoring materials in or to concrete or masonry. The materials to be anchored in or to concrete or masonry include, but are not limited to, metallic objects, such as steel bolts, ceramics, other concrete or masonry objects, plastics, glasses and woods.
The composition comprises methacrylate ester monomer, a methacrylate ester/methacrylic acid copolymer, a free-radical catalyst and a filler. It may also be desirable to include in the composition a thixotropic agent, a chain transfer agent, a free-radical inhibitor, a fragrance, an activator, a promoter and/or a pigment. It is also recognized that other components known to those skilled in the art may be included in the composition. Such components may include, but are not limited to, antifoaming agents, wetting agents, fungicides, impact modifiers, crosslinking agents and coupling agents.
The composition may be dispensed using various methods known to those skilled in the art. For example, the composition may be dispensed using a dual cartridge device similar to a caulk gun, or the composition may be dispensed using a glass or film capsule. The composition may also be dispensed in bulk from bulk containers using meter-mix equipment, which is known to those skilled in the art. U.S. Pat. Nos. 4,651,875, 4,706,806 and 4,729,696, the disclosures of which are hereby incorporated by reference, are directed to glass capsules. It is recognized that the amounts of the various components of the anchor composition may vary depending on the type of dispensing system used. In preferred dispensing methods, the anchor composition is formed by the mixing of a first composition and a second composition. Typically, the mixing occurs immediately before the anchor composition is to be used. For example, when the anchor composition is dispensed using a dispensing gun, the first composition and the second composition, which are contained in separate cartridges of the dispensing gun, may be mixed as they are ejected from the cartridges and applied to either the concrete or masonry, the material to be anchored to the concrete or masonry or both. Similarly, when the anchor composition is dispensed using a glass capsule, the capsule is typically comprised of two chambers that contain the first composition and the second composition respectively. When the glass capsule is crushed, the two chambers are crushed and the contents are allowed to mix, forming the anchor composition. Last, when the anchor composition is dispersed in bulk, a first composition and a second composition may be stored in separate bulk containers and combined through pumping with mixing in the appropriate ratio to make the anchor composition.
The anchor composition preferably contains a methacrylate ester monomer and a methacrylate ester/methacrylic acid copolymer. It is preferable if the methacrylate ester/methacrylic acid copolymer has a weight-average molecular weight in the range of about 10,000 to about 60,000. More preferably, the copolymer has weight-average molecular weight in the range of about 20,000 to about 40,000.
In general, the methacrylate ester/methacrylic acid copolymer is soluble in the methacrylate ester monomer to form a solution. The ratio of copolymer to monomer is in the range of about 1 to 9 to about 2.5 to 1 by weight. Preferably, the copolymer to monomer ratio is in the range of about 1 to 4 to about 1 to 1.5 by weight. More preferably, the copolymer to monomer ratio is in the range of about 1 to 4 to about 1 to 2.5 by weight.
As used herein, the phrase “methacrylate ester monomer” shall mean esters of methacrylic acid, including, but not l
Hackl Cyndie S.
Kish Fred A.
Rancich Michael J.
Illinois Tool Works Inc.
Synnestvedt & Lechner LLP
Szekely Peter
LandOfFree
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