Granular fertilizer with a multilayer coating
First Claim
1. A granular fertilizer with a multilayer coating comprising a first layer as an inner layer containing at least one rapidly biodegradable polymer selected from the group consisting of poly-L-lactic acid having a weight-average molecular weight of 70,000 to 500,000, polycaprolactone having a weight-average molecular weight of 10,000 to 70,000, aliphatic polyester having a weight-average molecular weight of 10,000 to 50,000 represented by the following formula (1):
- ##STR3## wherein m is 2 or 4, and x is 50 to 500; and
polyurethane having a weight-average molecular weight of 25,000 to 500,000 represented by the following formula (2);
##STR4## wherein n is 5 or 6 and Y is 70 to 1500; and
a water-insoluble second layer as an outer layer containing at least one slowly biodegradable polymer selected from the group consisting of at least one cellulose derivative having a weight-average molecular weight of 10,000 to 300,000 selected from the group consisting of of nitrocellulose, ethyl cellulose and triacetyl cellulose, low molecular weight polyethylene having a weight-average molecular weight of 500 to 10,000, low molecular weight wax having a weight-average molecular weight of 300 to 800, and a low molecular weight paraffin having a weight-average molecular weight of 300 to 800 or light degradable resin;
wherein the first layer is in an amount sufficient to control the dissolving-out rate of the fertilizer nutrients, and the second layer is in an amount sufficient to control the biodegradability of the first layer.
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Abstract
The present invention provides a granular fertilizer with a multilayer coating comprising a first layer containing at least one rapidly biodegradable polymer selected from the group consisting of a rapidly biodegradable aliphatic polyester and a rapidly biodegradable polyurethane compound, and a water-insoluble second layer containing at least one slowly biodegradable polymer selected from the group consisting of a slowly biodegradable cellulose derivative, low molecular weight polyethylene, low molecular weight wax and low molecular weight paraffin or light-degradable resins. The granular fertilizer with a multilayer coating of the present invention is characterized in that it is coated with coating materials having different dissolving-out rates, that dissolving-out of the fertilizer nutrients is controlled, and that the coating does not persist after the nutrients are dissolved out. Accordingly, the granular fertilizer coated with a multilayer of the present invention has less damaging effects on nature.
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Citations
7 Claims
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1. A granular fertilizer with a multilayer coating comprising a first layer as an inner layer containing at least one rapidly biodegradable polymer selected from the group consisting of poly-L-lactic acid having a weight-average molecular weight of 70,000 to 500,000, polycaprolactone having a weight-average molecular weight of 10,000 to 70,000, aliphatic polyester having a weight-average molecular weight of 10,000 to 50,000 represented by the following formula (1):
- ##STR3## wherein m is 2 or 4, and x is 50 to 500; and
polyurethane having a weight-average molecular weight of 25,000 to 500,000 represented by the following formula (2);
##STR4## wherein n is 5 or 6 and Y is 70 to 1500; and
a water-insoluble second layer as an outer layer containing at least one slowly biodegradable polymer selected from the group consisting of at least one cellulose derivative having a weight-average molecular weight of 10,000 to 300,000 selected from the group consisting of of nitrocellulose, ethyl cellulose and triacetyl cellulose, low molecular weight polyethylene having a weight-average molecular weight of 500 to 10,000, low molecular weight wax having a weight-average molecular weight of 300 to 800, and a low molecular weight paraffin having a weight-average molecular weight of 300 to 800 or light degradable resin;wherein the first layer is in an amount sufficient to control the dissolving-out rate of the fertilizer nutrients, and the second layer is in an amount sufficient to control the biodegradability of the first layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- ##STR3## wherein m is 2 or 4, and x is 50 to 500; and
Specification