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
2000-03-15
2002-05-28
Jagannathan, Vasu (Department: 1714)
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...
C524S803000, C525S059000
Reexamination Certificate
active
06395817
ABSTRACT:
BACKGROUND OF THE INVENTION
Poly(vinyl alcohol) has very low gas permeability making it especially useful as a gas barrier material. However, due in part to its high polarity, its melting point is close to its decomposition temperature which can be problematic in coating applications. In addition, poly(vinyl alcohol) polymers absorb moisture. One approach to alleviate these problems has been to introduce hydrocarbon units into the chain of the poly(vinyl alcohol) polymer to form copolymers.
Graft copolymerization of poly(vinyl alcohol) is a known method of changing the composition of poly(vinyl alcohol) in order to change the properties. For example
Polyvinyl Alcohol
-
Developments
, edited by C. A. Finch, Wiley, 1992, pages 449-453 contains information on the graft polymerization of vinyl acetate with poly(vinyl alcohol).
Polyvinyl Alcohol
, edited by C. A. Finch, Wiley, 1973, pages 438-442, reviews the use of ceric complexes in forming grafted copolymers of poly(vinyl aclohol) and several ethylenically unsaturated monomers, such as, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, and styrene.
Little is known about the polymerization, especially graft polymerization, of alkenes, and specifically ethylene, in a poly(vinyl alcohol) solution.
U.S. Pat. No. 3,926,934 (Lasswell, et al., 1975) discloses the production of polyethylene powders by high pressure polymerization of ethylene employing a water-soluble initiator, a controlled concentration of water, a dispersing agent, such as polyvinyl alcohol, and rapidly venting the polymerization zone or the polymerization effluent mixture withdrawn from the polymerization zone.
JP 51-73033 (1976) discloses wood adhesives which contain ethylenically unsaturated compounds or conjugated dienes graft-polymerized with poly(vinyl alcohol). Examples of ethylenically unsaturated compounds include styrene, acrylic and methacrylic acid and esters, unsaturated amides such as methacrylamide, and olefins, such as isobutylene. Butadiene and isoprene are examples of conjugated dienes. It is reported that a hydrophilic grafted polymer is formed in which the monomers are 0.2 to 5 parts by weight, per part by weight of poly(vinyl alcohol).
JP 64-45876 (1989) discloses the manufacture of a spray sizing agent consisting of a graft copolymer of poly(vinyl aclohol) and &agr;, &bgr;-monoethylenic monomers such that the ratio of poly(vinyl alcohol) to monomer is 100:5-100. Examples of &agr;, &bgr;- monoethylenic monomers include acrylates, methacrylates, vinyl acetate, and vinyl versitate. Other unsaturated monomers which reportedly can be combined with the above &agr;, &bgr;-monoethylenic monomers include styrene, acrylamide, vinyl chloride, and ethylene.
JP11-152316 (1999) discloses alkylated polyvinyl alcohol in which ethylene is added to the polyvinyl alcohol side chain. The addition reaction is carried out in an aqueous solution of poly(vinyl alcohol) at a pressure of 10 to 80 kg/cm
2
(1080 to 7948 kPa) using a radical initiator at levels of 0.1 to 100 wt %, preferably 1 to 50 wt %. In the examples, a 2.35 wt % aqueous solution of poly(vinyl alcohol) (PVA 217 and PVA 117; DPn=1700; hydrolysis of 88 mol % and 98 mol %, respectively; Kuraray Co.) was used to form alkylated polyvinyl alcohol. In the examples, the mean number of carbons in the grafted alkyl group was 12.6 to 13.8.
Poly(vinyl alcohol)-g-polyethylene copolymers have typically been made by grafting polyethylene to poly(vinyl alcohol). Examples of grafting methods are described below:
JP 58040323 (abstract) discloses the graft polymerization of poly(vinyl alcohol) onto HDPE films using &ggr; irradiation.
U.S. Pat. No. 4,575,532 (Schmukler et al., 1986) discloses a polyvinyl alcohol alloy which is prepared by reacting polyvinyl alcohol with a polyolefin which incorporates functional groups reactive with the hydroxyl groups in polyvinyl alcohol. Examples of suitable polyolefins are polyethylene, ethylene copolymers, and polypropylene.
U.S. Pat. No. 4,937,284 (Bergström, 1990) discloses the manufacture of olefin/vinyl alcohol block copolymers by joining polyvinyl alcohol to a polyolefin, such as low density polyethylene, low pressure polyethylene, high density polyethylene, and polypropylene, with the aid of silane.
Watanabe, T., et. al. (
Polym. Prepr.,
34(1), 1993, pp. 912-913) (abstract) discloses the graft modification of poly(vinyl alcohol) with succinic anhydride modified LDPE.
Poly(vinyl alcohol)-g-polyethylene graft emulsion copolymers in which ethylene is graft copolymerized to poly(vinyl alcohol) in an aqueous solution to form graft emulsion copolymers containing 50 wt % or more polyethylene have not been reported.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to aqueous based grafted copolymers comprising a polymer having a plurality of hydroxyl groups, preferably a vinyl alcohol homo- or copolymer, grafted with polyethylene, and optionally another polymerized ethylenically unsaturated monomer. The graft emulsion copolymers can contain 50 to 95 wt % polyethylene, 5 to 50 wt % hydroxyl-containing polymer, and up to 45 wt % of another polymerized ethylenically unsaturated monomer. Some homo- or copolymers of ethylene can also be present in the graft emulsion copolymer product.
The graft emulsion copolymers are prepared by polymerizing ethylene and, optionally another ethylenically unsaturated monomer, in an aqueous solution containing at least 5 wt %, preferably at least 10 wt %, of a polymer having a plurality of pendent hydroxyl groups, preferably poly(vinyl alcohol). The poly(vinyl alcohol) can have a degree of polymerization (DPn) of 50 to 2200, preferably 100 to 1000; and most preferably 100 to 300. A high solids, i.e., 10 to 65 wt %, preferably 30 to 60 wt %, graft emulsion copolymer product is formed.
The graft emulsion copolymer of this invention can be useful for films and provide unique performance features in a variety of applications, such as temperature sensitive adhesives, paper coatings, nonwoven coatings, binders for nonwovens, gas barrier films, and emulsion polymerization applications. The addition of a polyethylene to poly(vinyl alcohol) results in improvement of the hydrophobic properties, enhancement of oxygen barrier properties, improvement of tensile, and improved ease of film formation.
DETAILED DESCRIPTION OF THE INVENTION
The graft emulsion copolymers of this invention can be prepared by free radical initiated polymerization of ethylene, and, optionally, another ethylenically unsaturated monomer, in a solution of at least 5 wt %, preferably at least 10 wt %, of a polymer containing a plurality of pendent hydroxyl groups. The hydroxyl-containing polymer is preferably poly(vinyl alcohol).
Examples of other ethylenically unsaturated monomers are straight chain or branched alkenes, such propylene, butylene, isobutylene, pentene, and the like, wherein the number of carbons in the alkene ranges from 3 to 12, vinyl acetate, vinyl versatate, or other vinyl esters, alkyl acrylates, alkyl methacrylates, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, acrylamides, methacrylamides, N-methylolacrylamide, and combinations thereof; wherein alkyl is C
1
to C
6
alkyl.
Polymers having a plurality of pendent hydroxyl groups can be formed by the polymerization of vinyl or acrylic esters in which the ester unit contains from 1 to 4 carbon atoms. The pendent ester groups, when hydrolyzed, form polymers containing pendent hydroxyl groups. A preferred class of polymers having a plurality of pendent hydroxyl groups are based upon hydrolyzed vinyl acetate polymers wherein vinyl acetate is polymerized as a homopolymer or in conjunction with other monomers to form copolymers and are known as poly(vinyl alcohol) or vinyl alcohol copolymers. The amount of vinyl alcohol should be sufficient to enable free radical graft polymerization in an aqueous solution; i.e., render the polymer at least partially soluble in an aqueous medium. Typically the vinyl ester, specifically vinyl acetate, will comprise from 60 to 100% of the copolymer, preferably at lea
Lenney William Edward
Rabasco John Joseph
Air Products Polymers, L.P.
Bongiorno Mary E.
Jagannathan Vasu
Shasho Callie E.
LandOfFree
Poly(vinyl alcohol)-g-polyethylene graft emulsion copolymers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Poly(vinyl alcohol)-g-polyethylene graft emulsion copolymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Poly(vinyl alcohol)-g-polyethylene graft emulsion copolymers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2912765