Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1998-11-23
2001-07-03
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S296000, C525S328500, C516S135000, C162S164500
Reexamination Certificate
active
06255400
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a polymer, particularly an acrylamide polymer useful for applications such as an additive for paper making.
2. Description of the Related Art
Polymers including acrylamide polymers have been used in a variety of applications; specifically paper strength agents, surface coatings, drainage aids, retention aids, coagulants, water retainers, dispersants, concrete admixtures, enhanced oil recovery agents. In particular, it has been attempted that, for example, when used as a paper strength agent or a surface coating, an acrylamide polymer is combined with a cross-linking agent to have a partially cross-linked and branched structure, by which the polymer has an increased molecular weight while keeping the viscosity of its solution from being increased, for improving the polymer performance.
For example, there has been proposed a technique using a cross-linking compound for increasing molecular weight and lowering viscosity. Specific compounds used include cross-linking vinyl monomers such as difunctional vinyl monomers including methylene bis(meth)acrylamide, ethyleneglycol di(meth)acrylate, diallyl (meth)acrylamide and divinyl adipate; trifunctional monomers including 1,3,5-triacryloylhexahydro-S-triazine; and tetrafunctional monomers including N,N,N′,N′-tetraallyl-1,4-diaminobutane, as well as silicone compounds including vinyltriethoxysilane. A molecular-weight increasing technique based on a cross-linking reaction depending only on such a cross-linking compound, has many problems such as higher nonuniformity of a branched and cross-linked structure; in particular, when using a multifunctional vinyl monomer, the solution may become more viscous with the elapse of time. Thus, such a polymer is not satisfactory as a paper strength agent.
Furthermore, it has been attempted that in addition to these cross-linking compounds, a particular compound is combined for providing an acrylamide polymer with a branched and cross-linked structure. Known combinations include those of a cross-linking compound and a primary or a hydroxylated monomer, a cross-linking compound and a particular hydrophobic monomer, and a cross-linking compound and an itaconic acid derivative. It has been implicated that a polymer from any of these combinations may have an increased molecular weight with a lower viscosity. Such polymers are, however, not satisfactory as a paper strength agent in view of their structures. In fact, they have not provided satisfactory results. Besides the previous improvement, a more improved paper strength agent has been desired.
There have been needs for a paper power agent with a more improved performance because paper-making conditions have been increasingly harsh in a paper making process, such as an increase in a wastepaper rate, an increase of pH value in sheet forming, an increase in a rate of a closed white water due to, e.g., effluent regulation, speedup of a paper machine. Overcoming the problem of reduction in a durability of paper is particularly important. Depending on the application, reduction in a Z-axis directional strength as a component of a durability of a paper may be often a significant problem. Paper power agents for improving a Z-axis directional strength have been disclosed. It is known that a cationic acrylamide polymer obtained by Hofmann degradation of an acrylamide polymer is highly effective. However, higher level of Z-axis directional strength is desired.
Meanwhile, many of surface coatings mainly comprise an anionic polymer. Attempts have been previously made, for example, for increasing a molecular weight by incorporating a cross-linked structure and for saving a transportation cost by concentrating of a coating. However, advanced control techniques of polymer structure have not been introduced.
SUMMARY OF THE INVENTION
This invention relates to a polymer, particularly an acrylamide polymer, prepared by a novel polymerization technique. Specifically, it relates to a polymer, particularly an acrylamide polymer, prepared by polymerization in the presence of a polymer having a particular vinyl monomer unit. An objective of this invention is to provide a polymer, particularly an aqueous solution of an acrylamide polymer, with good drainage and paper strength properties and a higher molecular weight but a lower viscosity, as well as a manufacturing process therefor. Another objective of this invention is to provide an additive for paper making such as a paper strength agent, surface coating or drainage aid comprising the above polymer, particularly the above acrylamide polymer.
We have intensively investigated acrylamide polymers in the light of the above circumstances, and have found that a polymer whose structure is well controlled can be provided by means of a novel polymerization technique.
This invention provides the following (1) to (25).
(1) A polymer (B) prepared by polymerizing one or more vinyl monomers (c) in the presence of a polymer (A) prepared by polymerizing one or more vinyl monomers (a) selected from the group consisting of vinyl monomers represented by the general formula (1):
wherein R
1
represents a hydrogen atom or a lower alkyl with 1 to 3 carbon atoms and n is an integer of 1 to 8 and their salts with one or more vinyl monomers (b) which are co-polymerizable with the vinyl monomer components (a);
(2) A polymer (B) according to (1), wherein the weight average molecular weight of the polymer (A) is 1,000 to 5,000,000;
(3) A polymer (B) according to (1), wherein at least one of the vinyl monomers (b) is (meth)acrylamide;
(4) A polymer (B) according to (1), wherein at least one of the vinyl monomers (c) is (meth)acrylamide;
(5) A polymer (B) according to (1), wherein at least one of the vinyl monomers (b) and at least one of the vinyl monomers (c) are (meth)acrylamide;
(6) A polymer (B) according to (1), wherein the polymer (A) consists of the same vinyl monomer components as those of the polymer (B), and at least one vinyl monomer component has a molar ratio in the polymer (A) substantially different from that in the polymer (B);
(7) A polymer (B) according to (1), wherein the remaining vinyl monomer composition after subtracting the vinyl monomer composition of the polymer (A) from that of the polymer (B), is different from the composition of the polymer (A);
(8) A polymer (B) according to (1), wherein the components or the composition are substantially different between the polymers (A) and (B);
(9) A polymer (B) according to (1), wherein at least one of vinyl monomers (b) is an ionic monomer;
(10) A polymer (B) according to (1), wherein at least one of vinyl monomers (b) is an anionic monomer;
(11) A polymer (B) according to (1) having a weight average molecular weight of 100,000 to 10,000,000;
(12) A polymer (B) according to (1) comprising a cross-linking vinyl monomer as a component monomer;
(13) A paper strength agent comprising the polymer (B) according to (1);
(14) A surface coating comprising the polymer (B) according to (1);
(15) A paper strength agent comprising the polymer (B) according to (10);
(16) A surface coating comprising the polymer (B) according to (10);
(17) A process for manufacturing a polymer (B), comprising the steps of
preparing a polymer (A) by polymerizing one or more vinyl monomers (a) selected from the group consisting of vinyl monomers represented by the general formula (1):
wherein R
1
represents a hydrogen atom or a lower alkyl with 1 to 3 carbon atoms and n is an integer of 1 to 8 and their salts with one or more vinyl monomers (b) which are co-polymerizable with the vinyl monomer components (a); and
polymerizing one or more vinyl monomers (c) in the presence of the polymer (A);
(18) A cationic polymer (C) prepared by Hofmann degradation of the polymer (B) according to (1) wherein one or both of the vinyl monomers (b) and (c) comprise a monomer having an amide group, at an alkaline pH;
(19) A cationic polymer (C) according to (18) wherein the monomer having an amide group is (meth)acrylamide;
(20)
Doki Hirotoshi
Itoh Hiroshi
Matsubara Tsugio
Nakamura Ken'ichi
Oyama Susumu
Burns Doane Swecker & Mathis L.L.P.
Gorr Rachel
Mitsui Chemicals Inc.
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