Production method and production apparatus of particulate water absorbing agent containing water absorbent resin as main component
First Claim
1. A method for producing a particulate water absorbing agent, said method comprising the steps of:
- (a) circulating, in a neutralization system including a neutralization tank, a mixture solution containing an acid group-containing monomer and salt obtained by a neutralization reaction of the acid-containing monomer with a basic material;
(b) continuously supplying, to a polymerization system, a part of the mixture solution that is being circulated; and
(c) polymerizing a monomer component of the mixture solution in the polymerization system,the method satisfying a requirement that a value X is not more than 200, the value X being found according to the following expression;
X=(V/F)·
A wherein V (kg) is a volume of the mixture solution present in the neutralization system, F (kg/h) is a flow volume of the mixture solution to be supplied to the polymerization system, and A(m2) is a contact area of the mixture solution present in the neutralization system with a device(s) and a pipe(s) constituting the neutralization system.
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Accused Products
Abstract
An apparatus (2) includes a neutralization tank (3), a pump (4), a heat exchanger (6), a line mixer (8), a polymerizer (10), a first pipe (12), a second pipe (14), a third pipe (16), a fourth pipe (18), and a fifth pipe (20). Continuously supplied into the neutralization tank (3) are a monomer aqueous solution and a basic aqueous solution, so as to prepare a mixture solution. The mixture solution is circulated through the first pipe (12), the pump (4), the second pipe (14), the heat exchanger (6), and the third pipe (16). The mixture solution is supplied to the polymerizer through the fourth pipe (18). The apparatus (2) satisfies a requirement that a value X is not more than 200, which value X is found according to the following expression: “X=(V/F)·A”, wherein V is a volume of the mixture solution present in a neutralization system, F is a flow volume of the mixture solution to be supplied to a polymerization system, and A is a contact area of the mixture solution present in the neutralization system with a device(s) and a pipe(s) constituting the neutralization system. With this arrangement, it is possible to provide a water absorbent resin having superior whiteness.
19 Citations
21 Claims
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1. A method for producing a particulate water absorbing agent, said method comprising the steps of:
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(a) circulating, in a neutralization system including a neutralization tank, a mixture solution containing an acid group-containing monomer and salt obtained by a neutralization reaction of the acid-containing monomer with a basic material; (b) continuously supplying, to a polymerization system, a part of the mixture solution that is being circulated; and (c) polymerizing a monomer component of the mixture solution in the polymerization system, the method satisfying a requirement that a value X is not more than 200, the value X being found according to the following expression;
X=(V/F)·
Awherein V (kg) is a volume of the mixture solution present in the neutralization system, F (kg/h) is a flow volume of the mixture solution to be supplied to the polymerization system, and A(m2) is a contact area of the mixture solution present in the neutralization system with a device(s) and a pipe(s) constituting the neutralization system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13)
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9. A method for producing a water absorbent resin, said method comprising the steps of:
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(1) in a neutralization system including a neutralization tank, a first loop, and a second loop, circulating through the first loop a mixture solution which is present in the neutralization tank and which contains an acid group-containing monomer and salt obtained by a neutralization reaction of the acid group-containing monomer with a basic material; (2) causing the mixture solution to be drawn from the neutralization tank or the first loop into the second loop so that the mixture solution is carried through the second loop to a place closer to a polymerization system than to the first loop, and then causing the mixture solution to return back through the second loop to the neutralization tank or the first loop; and (3) continuously supplying the mixture solution from the neutralization system to the polymerization system. - View Dependent Claims (18, 19, 20, 21)
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14. A production apparatus for producing a water absorbent resin, said production apparatus comprising:
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a neutralization system; a polymerization system; and a pipe connecting the neutralization system to the polymerization system, the neutralization system including; a neutralization tank in which to store a mixture solution containing an acid group-containing monomer and salt obtained by a neutralization reaction of the acid group-containing monomer with a basic material; a first loop for drawing the mixture solution from the neutralization tank and for returning the mixture solution back to the neutralization tank; and a second loop for drawing the mixture solution from the neutralization tank or the first loop so that the mixture solution is carries through the second loop to a place closer to the polymerization system than to the first loop, and for retuning the mixture solution back to the neutralization tank or the first loop, the mixture solution being continuously supplied from the neutralization system to the polymerization system via the pipe, said production apparatus satisfying a requirement that a value X is not more than 200, the value X being found according to the following expression;
X=(V/F)·
Awherein V (kg) is a volume of the mixture solution present in the neutralization system, F (kg/h) is a flow volume of the mixture solution to be supplied to the polymerization system, and A(m2) is a contact area of the mixture solution present in the neutralization system with a device(s) and a pipe(s) constituting the neutralization system. - View Dependent Claims (15, 16, 17)
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Specification