US 5,156,718 AGrant
Paper Mats
Issue Date:1992-10-20
•4 Claims
Abstract
A paper mat is made from an aqueous slurry or dispersion of kraft wood pulp, a large amount of finely divided inorganic pigments and as a binder an anionic latex of a copolymer of at least one conjugated diene monomer, at least one vinyl substituted aromatic monomer, at least one acrylic-type monomer and at least one monomer having a vinyl group and an activatable methyl, ethyl, propyl or butyl ester group. The mat of this invention exhibits improved properties over mats made from other latex binders.
Metadata
Assignee
- GenCorp Inc.
Inventor
- Terry C. Neubert
Application Information
Application Number:US 643391&
Filing Date:1991-01-18
Priority Date:1989-11-03
Art Unit:133
Classifications
IPC:
D21H 1314
Field of Search:
162145;146;168.1;168.2;168.3;158;169;160;168.4;168.6;168.7;181.6;181.8
Patent Drawings
This patent does not have any drawings.
Description
The following examples will serve to illustrate the present invention with more particularity to those skilled in the art.
Examples
Aqueous slurries were prepared from, on a dry parts-by-weight basis:
The slurries were flocculated with catiomic flocculation cast onto wire screens to remove the water to form sheets which were compressed, heated and cooled to form mats which were then tested.
The anionic latices used were the following copolymers (parts by weight of monomers):
A. Copolymer of 40 butadiene, 51.5 styrene, 1.5 itaconic acid, 2 acrylamide and 5 methyl acrylamidoglycolate methyl ether ##STR1##
B. Copolymer of 42 butadiene-1,3, 54 styrene, 0.5 itaconic acid, 3 acrylamide and 0.5 methacrylic acid.
C. Copolymer of 45 butadiene, 51 styrene, 0.5 itaconic acid, 3 acrylamide and 0.5 methacrylic acid.
D. Copolymer of 51 butadiene and 49 styrene.
E. Copolymer of 48.75 butadiene-1,3, 44.25 styrene, 1.5 itaconic acid, 2.5 acrylamide, 2.5 N-methylolacrylamide and 0.5 divinylbenzene.
F. Same as E but from a larger batch of latex.
G. Blend of 30% of a copolymer of 30 butadiene-1,3, 65.25 styrene, 0.75 methacrylic acid, 1.75 hydroxyethylacrylate and 2.25 itaconic acid and 70% of a copolymer of 45 butadiene-1,3, 51 styrene, 0.5 itaconic acid, 3 acrylamide and 0.5 methacrylic acid.
H. Commercial latex.
I. Same as copolymer B.
The results show that mats made from copolymer A gave better results than mats from copolymer B and I (the controls). Further runs of mats made from copolymer A exhibited improvement in ambient tensile, hot tensile, ambient plasticizer tensile, hot plasticizer tensile and split strength over mats made from other copolymers.
Claims
What is claimed is:
1. The method which comprises forming an aqueous slurry to make a mat comprising on a dry weight basis from about, in parts by weight: 5.0 to 20.0 kraft wood pulp 0.5 to 3.0 polyethylene particles 60.0 to 85.0 finely divided clay or talc 1.0 to 2.0 chopped glass fibers 0.1 to 0.0015 antioxidant 0.01 to 0.02 water clarifier, and 8.0 to 16.0 copolymer binder (from an anionic latex) ______________________________________ forming a sheet on a screen from the slurry, removing water from the slurry using the screen to form a sheet, compressing the sheet and drying and cooling the sheet to form a paper mat wherein the latex of the copolymer binder has a solids content of from about 40 to 60% and wherein the copolymers of the latex comprises: (a) from about 30 to about 60% by weight of at least one conjugated diene monomer selected from the group consisting of butadiene-1,3, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, pentadiene and hexadiene. (b) from about 36 to 66% by weight of at least one vinyl substituted aromatic monomer selected from the group consisting of styrene, alpha methyl styrene, para methyl styrene, methyl vinyl toluene, p-vinyl toluene and 3-ethylstyrene. (c) from about 1 to 4% by weight of at least one acrylic type monomer selected from the group consisting of acrylamide, methacrylamide, itaconic acid, acrylic acid and methacrylic acid. (d) from about 3 to 6% by weight of at least one monomer having a vinyl group and an activatable methyl, ethyl, propyl or butyl ester group, and selected from the group consisting of methyl acrylamidoglycolate, ethyl acrylamidoglycolate, butyl acrylamidoglycolate, methyl acrylamidoglycolate methyl ether, butyl acrylamidoglycolate butyl ether, methyl methacrylaoxyacetate, ethyl acrylamido-N-oxalate (N-ethyloxalyl acrylamide), N, N'-Bis (ethyloxalyl) acrylamide, N-isopropyl, N-ethyloxalyl-3-propylamino methacrylamide, N-ethyloxalyl-N'-methyleneaminoacrylamide, ethyl N-2-ethyloxamatoacrylate, ethyl 3-pyruvylacrylate, ethyl methylenepyruvate, methyl acrylthiocarbonyl-oxyacetate (methyl thiacryloxyacetate), methyl thiacrylthioglylcolate, methyl acryl-2-thioglycolate, methyl acryl-2-thioglycolate, methyl thiacrylamidoacetate, methyl acrylamidoglycolate thioether, methyl acrylamido-N-methylenethioglycolate and p-ethyl oxalyl styrene.
2. The method according to claim 2, wherein said conjugated diene monomer is butadiene-1,3-where said vinyl substituted aromatic monomer is styrene, where said acrylic-type monomer is a mixture of itaconic acid and acrylamide and where the monomer having a vinyl group and an activatable vinyl, ethyl, propyl or butyl ester group is methylacrylamidoglycolate methyl ether.
3. The product produced by the method of claim 2.
4. A paper mat comprising about, in a dry weight basis, in parts by weight: 5.0 to 20.0 kraft wood pulp 0.5 to 3.0 polyethylene particles 60.0 to 85.0 finely divided clay or talc 1.0 to 2.0 chopped glass fibers 0.0 to 0.0015 antioxidant 0.01 to 0.02 water clarifier, and 8.0 to 16.0 copolymer binder from an anionic latex having a solids content of from about 40 to 60% by weight ______________________________________ wherein the copolymer comprises (a) from about 30 to 60% by weight of at least one conjugated diene selected from group consisting of butadiene-1,3, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, pentadiene and hexadiene, (b) from about 36 to 66% by weight of at least one vinyl substituted aromatic monomer selected from the group consisting of styrene, alpha methyl styrene, para methyl styrene, methyl vinyl toluene, p-vinyl toluene and 3-ethyl stryene, (c) from about 1 to 4% by weight of at least one acrylic type monomer selected from the group consisting of acrylamide, methylacrylamide, itaconic acid, acrylic acid and methacrylic acid, (d) from about 3 to 6% by weight of at least one monomer having a vinyl group and an activatable methyl, ethyl, propyl or butyl group and selected from the group consisting of: methyl acrylamidoglycolate ethyl acrylamidoglycolate butyl acrylamidoglycolate methyl acrylamidoglycolate methyl ether butyl acrylamidoglycolate butyl ether methyl methacrylaxyacetate ethyl acrylamido-N-oxalate (N-ethyloxalyl acrylamide) N-N'-Bis(ethyloxalyl)acrylamide ethyl N-2-ethyloxamatoacrylate ethyl 3-pyruvylacrylate methyl acrylthiocarbonyloxyacetate (Methyl thia-cryloxyacetate) methyl thiacrylthiogylcolate methyl acryl-2-thioglycolate methyl thiacrylamidoacetate methyl acrylamidoglycolate thioether methyl acrylamido-N-methylenethioglycolate, and p-ethyl oxalyl styrene.