Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-01-22
2002-06-04
Henderson, Christopher (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S812000, C524S817000, C526S201000, C526S225000, C526S295000
Reexamination Certificate
active
06399702
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous butadiene latex, particularly an aqueous butadiene latex that is compatible with an aqueous phenolic resin. The butadiene latex is especially useful in aqueous adhesive or primer compositions.
Various techniques are known to emulsion polymerize butadiene polymers to obtain an aqueous latex. For example, according to an English translation, DE-A-33 21 902 relates to an aqueous emulsion polymerization for making chloroprene rubber than involves polymerizing chloroprene, optionally with up to 50 weight percent of a copolymerizable monomer, in the presence of 0.5 to 5 weight percent of a rosin acid derivative and 0.1 to 10 weight percent of a polystyrene sulfonic acid derivative, based on the weight of the total monomers. Copolymers of 95 weight percent chloroprene/5 weight percent 2,3-dichlorobutadiene are exemplified. The addition of the polystyrene sulfonic acid was shown to reduce the adhesion of the chloroprene rubber to a metal mold.
U.S. Pat. No. 4,054,547 relates to a process for copolymerizing chloroprene and 0.5-10 weight percent (based on total monomers) of at least one styrene sulfonic acid or a water soluble derivative thereof in an aqueous medium to form latex particles. The addition of an ethylenically unsaturated co-monomer to the system is mentioned. 2,3-dichlorobutadiene is listed as a possible co-monomer.
U.S. Pat. No. 4,400,229 relates to an aqueous dispersion of a phenolic resole and a thermoplastic polymeric material or a rubber prepared by dissolving a solid thermoplastics material or a rubber into a liquid phenol; adding a nonionic or anionic surface active agent and/or protective colloid; adjusting the pH of the mixture to above 7; adding aqueous formaldehyde solution or a formaldehyde donor and heating the mixture to form a phenolic resole.
U.S. Pat. No. 4,500,692 relates to suspension polymerization of a vinyl aromatic monomer in the presence of an inorganic phosphate suspension system and sodium polystyrenesulfonate. The possibility of copolymerization of the vinyl aromatic monomer with a co-monomer is briefly mentioned. Butadiene is included in a list of possible co-monomers.
U.S. Pat. No. 5,051,461 relates to an emulsion of metal neutralized sulfonated copolymer of a conjugated diene and an ethoxylated alkylamine salt of styrene sulfonate, and a tackifier resin. U.S. Pat. No. 4,530,987 relates to a polymer of at least 80% by weight of a conjugated diene and a minor proportion of a metal or amine neutralized styrene sulfonate monomer.
U.S. Pat. No. 5,162,156 relates to a primer composition that includes (a) novolak phenolic resin and (b) a halogenated polyolefin. Dichlorobutadiene polymers are listed as possible halogenated polyolefins.
Commonly-assigned U.S. patent application Ser. No. 08/889,294, filed Jul. 8, 1997, relates to an aqueous adhesive composition that includes a halobutadiene homopolymer latex, an aqueous soluble or dispersible phenolic resin and a maleimide-based compound 2,3-dichloro-1,3-butadiene is the preferred halobutadiene monomer.
U.S. Pat. Nos. 5,200,459; 5,300,555; and 5,496,884 disclose emulsion polymerization of dichlorobutadiene monomers in the presence of polyvinyl alcohol and a co-solvent such as an organic alcohol or a glycol. Polyvinyl alcohol-stabilized dichlorobutadiene latex has been successfully commercialized, but it has a few drawbacks.
In particular, the use of a volatile organic co-solvent requires its removal from the emulsion latex. If not all the co-solvent is removed, the resulting latex may have an unacceptably high amount of volatile organic compounds (VOC). In addition, a high concentration of surfactants is used in the emulsion polymerization. High concentration of surfactants in adhesive compositions may cause the well-known “surfactant penalty” problem in the performance of the adhesive. The latex also suffers from compatibility problems when mixed with a water soluble phenolic resin or an aqueous dispersion or emulsion of a phenolic resin. A butadiene latex that alleviates these problems would be very desirable.
SUMMARY OF THE INVENTION
According to the present invention there is provided a stable aqueous butadiene polymer latex that utilizes a lower amount of surfactants relative to polyvinyl alcohol-stabilized butadiene latices and exhibits excellent compatibility with other aqueous components such as latices, dispersions or solutions. An important advantage of the butadiene polymer latex is its compatibility with phenolic resins. The butadiene polymer in emulsion polymerized in the presence of a styrene sulfonic acid, styrene sulfonate, poly(styrene sulfonic acid), or poly(styrene sulfonate) stabilizer to form the latex. Poly(styrene sulfonate) is the preferred stabilizer. This stabilization system is particularly effective for a butadiene polymer that is derived from at least 60 weight percent dichlorobutadiene monomer, based on the amount of total monomers used to form the butadiene polymer.
Thus, according to one embodiment there is provided an aqueous butadiene polymer latex that is prepared by emulsion polymerization of at least 60 weight percent dichlorobutadiene monomer (based on the amount of total monomers used to form the butadiene polymer), in the presence of a styrene sulfonic acid, styrene sulfonate, poly(styrene sulfonic acid), or poly(styrene sulfonate) stabilizer. According to a second embodiment there is provided an aqueous composition that includes (A) a butadiene polymer latex that is prepared by an emulsion polymerization in the presence of a styrene sulfonic acid, styrene sulfonate, poly(styrene sulfonic acid), or poly(styrene sulfonate) stabilizer and (B) a phenolic resin.
The butadiene polymer latex of the invention is particularly useful in liquid adhesives or primers, especially adhesives or primers for bonding a polymeric surface to a metallic surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Unless otherwise indicated, description of components in chemical nomenclature refers to the components at the time of addition to any combination specified in the description, but does not necessarily preclude chemical interactions among the components of a mixture once mixed.
Certain terms used in this document are defined below.
“Butadiene polymer” means a polymer prepared from butadiene monomers alone or from a combination of butadiene monomers and other copolymerizable monomers described in more detail below. “Butadiene polymer,” therefore, refers to butadiene homopolymer, butadiene copolymer, butadiene terpolymer, and higher polymers.
“Phenolic compound” means a compound that includes at least one hydroxy functional group attached to a carbon atom of an aromatic ring. Illustrative phenolic compounds include unsubstituted phenol per se, substituted phenols such as alkylated phenols and multi-hydroxy phenols, and hydroxy-substituted multi-ring aromatics. Illustrative alkylated phenols include methylphenol (also known as cresol), dimethylphenol (also known as xylenol), 2-ethylphenol, pentylphenol and tert-butyl phenol. “Multi-hydroxy phenolic compound” means a compound that includes more than one hydroxy group on each aromatic ring. Illustrative multi-hydroxy phenols include 1,3-benzenediol (also known as resorcinol), 1,2-benzenediol (also known as pyrocatechol), 1,4-benzenediol (also known as hydroquinone), 1,2,3-benzenetriol (also known as pyrogallol), 1,3,5-benzenetriol and 4-tert-butyl-1,2-benzenediol (also known as tert-butyl catechol). Illustrative hydroxy-substituted multi-ring aromatics include 4,4′-isopropylidenebisphenol (also known as bisphenol A), 4,4′methylidenebisphenol (also known as bisphenol F) and naphthol.
“Aldehyde compound” means a compound having the generic formula RCHO. Illustrative aldehyde compounds include formaldehyde, acetaldehyde, propionaldehyde, n-butylaldehyde, n-valeraldehyde, caproaldehyde, heptaldehyde and other straight-chain aldehydes having up to 8 carbon atoms, as well as compounds that decompose to formaldehyde such as paraformaldehyde, trioxane, furf
Kucera Helmut W.
Rizzo Thomas
Dearth Miles B.
Henderson Christopher
Lord Corporation
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