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
1998-12-08
2001-09-25
Wilson, Donald R. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S329200, C525S378000, C525S382000, C526S258000, C526S260000, C526S264000, C526S265000
Reexamination Certificate
active
06294615
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a copolymer, a cationic high molecular weight flocculating agent comprising the copolymer, and a process for producing the copolymer.
BACKGROUND OF THE INVENTION
Cationic polymers are used as flocculating agents, chemicals for papers, and the like. Of those, a cationic polymer having a high aqueous solution viscosity is used as a flocculating agent, especially as a flocculating agent for organic sludge.
A copolymer having a unit represented by the following formula (5) is obtained by contacting a copolymer having a unit represented by the following formula (6) with an acid as described in, for example, JP-B-42-9653 (The term “JP-B” as used herein means an “examined Japanese patent publication). However, Brookfield viscosity of the aqueous solution thereof is low and, therefore, when the copolymer is used as a cationic high molecular weight flocculating agent, the flocculating performance thereof is not sufficient.
wherein R
1
, R
2
and R
3
each independently represent a hydrogen atom, an aliphatic group, aralkyl group or aromatic group, each group of which may have a functional group; R
4
represents a hydrogen atom or methyl group; and X represents an anion.
It is known that the copolymer having the unit represented by the above-described formula (5) is obtained by a reaction of a copolymer containing (meth)acrylonitrile with a polyamine using sulfur as a catalyst. Such conventional methods include a method using an excess amount of a polyamine (as described in, for example, JP-B-42-6271 and 42-9653); a method wherein a copolymer containing (meth)acrylonitrile is dispersed in a non-solvent therefor to react as described in, for example, JP-B-42-6271, and JP-A-58-96604, 61-83205, 61-83206, 61-83207 and 62-34905 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”); and a method wherein a reaction is conducted in a mixed state of a copolymer containing (meth)acrylonitrile and a polyamine-insoluble solid filler as described in, for example, JP-A-61-285202.
These methods, however, use sulfur as the catalyst, so that extremely toxic hydrogen sulfide is produced as a by-product during reaction. The generated hydrogen sulfide forms a salt with the product. Therefore, it was not easy to eliminate the hydrogen sulfide in the product.
The products obtained according to these methods had the problems that they formed a mass during the reaction or they became partially insoluble in water.
Conventionally, when the copolymer having the unit represented by the above-described formula (5) was used as a flocculating agent, the Brookfield viscosity of the aqueous solution thereof was low and, therefore, it was not sufficient as a flocculating agent. Further, the production method of the copolymer also had the problems that hydrogen sulfide was formed as a by-product, the product became a solid mass during the reaction, and the product became partially insoluble in water. Thus, the above-described copolymer was industrially insufficient.
Accordingly, a copolymer having the unit represented by the above-described formula (5) and also having a high Brookfield viscosity as an aqueous solution thereof as well as a method for producing the same have been desired to be developed. Thus, the object of the present invention is to provide a copolymer having the unit represented by the above-described general formula (5) and also having a high viscosity as an aqueous solution thereof, the cationic high-molecular flocculating agent comprising the same, and the process for producing the same.
SUMMARY OF THE INVENTION
As a result of extensive investigations with respect to the kinds of acid salts in the unit represented by the above-described formula (5) and also units constituting the copolymer other than the unit represented by the above-described formula (5) in order to overcome the above-described problems, a copolymer having a high aqueous solution viscosity and showing excellent flocculating performance as a cationic high molecular weight flocculating agent, and a method for producing the same have been found. The present invention has been completed based on those findings.
Accordingly, one object of the present invention is to provide a copolymer comprising a unit represented by the formula (1) described hereinafter and a unit represented by the formula (2) described hereinafter, and also having high viscosity as an aqueous solution thereof.
Another object of the present invention is to provide a cationic high molecular weight flocculating agent comprising the copolymer. This cationic high molecular weight flocculating agent has excellent filtration property, and excellent aggregation property which can decrease water content in dehydrated cake. Further, use of the agent can form flocks having a large size.
Still another object of the present invention is to provide a process for producing the copolymer. This production process has the advantages that hydrogen sulfide is not by-produced, the reaction product does not form a solid mass during reaction, and the reaction product completely dissolves in water.
According to one embodiment of the present invention, there is provided a copolymer comprising a unit represented by the following formula (1) and a unit represented by the following formula (2):
wherein R
1
, R
2
and R
3
each independently represent a hydrogen atom, an aliphatic group, an aralkyl group or an aromatic group, each group of which may have a functional group; R
4
represents a hydrogen atom or methyl group; and R
5
represents an alkylene group having 2 to 5 carbon atoms; the copolymer having a Brookfield viscosity as a 1 wt % aqueous solution thereof of 10 to 10,000 centipoise at 25° C.
According to another embodiment of the present invention, there is provided a cationic high molecular weight flocculating agent comprising the copolymer.
According to still another embodiment of the present invention, there is provided a process for producing the copolymer comprising a unit represented by the above-described formula (1) and a unit represented by the above-described formula (2), the copolymer having a Brookfield viscosity of 1 wt % aqueous solution thereof of 10 to 10,000 centipoise at 25° C., which comprises reacting a copolymer comprising a unit represented by the above-described formula (2) and a unit represented by the following formula (3):
wherein R
6
represents a hydrogen atom or methyl group, with a polyamine in the presence of at least one of ammonium chloride and a hydrochloride of an amine.
REFERENCES:
patent: 3288707 (1966-11-01), Hurwitz et al.
patent: 4109072 (1978-08-01), Panzer et al.
patent: 4113934 (1978-09-01), Panzer et al.
patent: 4595731 (1986-06-01), Wilkinson
patent: 42-6271 (1942-03-01), None
patent: 42-9653 (1942-05-01), None
patent: 58-96604 (1983-06-01), None
patent: 61-83205 (1986-04-01), None
patent: 61-83206 (1986-04-01), None
patent: 61-83207 (1986-04-01), None
patent: 61-285202 (1986-12-01), None
patent: 62-34905 (1997-02-01), None
Higashino Toshiya
Inoue Hiroshi
Sughrue Mion Zinn Macpeak & Seas, PLLC
Tosch Corporation
Wilson Donald R.
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