Self-rupturing composite sustained-release membrane and sustained-release coating

Abstract

A self-rupturing composite sustained-release membrane comprises a polymer membrane and a self-crystallizing material. The polymer membrane has an inner surface and an outer surface arranged opposite to each other. The self-crystallizing material is distributed in the polymer membrane and comprises a silicate filler and a calcium-containing filler, with the weight ratio of the silicate filler to the calcium-containing filler being between 1:0 and 1:3. The silicate filler and the calcium-containing filler react in an aqueous environment to form a calcium silicate crystal. When the content of the calcium-containing filler in the self-crystallizing material is 0, the polymer membrane contacts a calcium-containing substance, and the silicate filler and the calcium-containing substance react in an aqueous environment to form a calcium silicate crystal. The polymer membrane generates multiple cracks corresponding to the positions of the calcium silicate crystals, and some cracks penetrate the inner and outer surfaces. A sustained-release coating provided in another embodiment is also disclosed herein.

Claims

1. A self-rupturing composite sustained-release membrane, comprising: a polymer membrane body, which is a single-layer structure, the polymer membrane body having an inner surface and an outer surface disposed opposite to each other; and a self-crystallizing material distributed in the polymer membrane body, the self-crystallizing material comprising a silicate filler and a calcium-containing filler, the weight ratio of the silicate filler to the calcium-containing filler being between 1:0 and 1:3, the silicate filler and the calcium-containing filler react in an aqueous environment to form a calcium silicate crystal; when the content of the calcium-containing filler in the self-crystallizing material is 0, the polymer membrane body contacts a calcium-containing substance, the silicate filler and the calcium-containing substance in the polymer membrane body react in the aqueous environment to form the calcium silicate crystal, wherein the polymer membrane body generates a plurality of cracks corresponding to the positions of the calcium silicate crystals, and some cracks penetrate the inner surface and the outer surface.

2. The self-rupturing composite sustained-release membrane as described in claim 1, wherein the content of the polymer membrane accounts for 90-95 wt% of the total weight of the self-rupturing composite sustained-release membrane, and the content of the self-crystallizing agent accounts for 5-10 wt% of the total weight of the self-rupturing composite sustained-release membrane.

3. The self-rupturing composite slow-release membrane as described in claim 1, wherein the silica filler is selected from one or more of the group consisting of sodium silicate, potassium silicate and silicon dioxide; and the calcium-containing filler is selected from one or more of the group consisting of calcium hydroxide, calcium chloride and calcium oxide.

4. The self-rupturing composite slow-release membrane as described in claim 2, wherein the weight ratio of the silica filler to the calcium-containing filler is between 1:1 and 1:

3.

5. The self-rupturing composite sustained-release membrane as described in claim 1, wherein the thickness of the polymer membrane is between 50 and 200 μm; the polymer membrane is selected from one or more of the group consisting of acrylic, polyurethane, vinyl acetate-ethylene copolymer and wax; and the calcium-containing substance is selected from calcium-containing minerals or lime.

6. A sustained-release coating comprising: a coated carrier; and a self-rupturing composite sustained-release membrane, wherein the coated carrier is coated by the self-rupturing composite sustained-release membrane, the self-rupturing composite sustained-release membrane having a polymer membrane and a self-crystallizing material, the polymer membrane being a single-layer structure, the polymer membrane being attached to the periphery of the coated carrier, the polymer membrane having an inner surface and an outer surface disposed opposite to each other, the inner surface contacting the coated carrier, the self-crystallizing material being distributed within the polymer membrane, the self-crystallizing material comprising a silicate filler and a calcium-containing filler, the weight ratio of the silicate filler to the calcium-containing filler being between 1:0 and 1:

3. The silica filler and the calcium-containing filler react in an aqueous environment to form a calcium silicate crystal from the self-crystallized material. When the content of the calcium-containing filler in the self-crystallized material is 0, the coated carrier contains a calcium-containing substance. The silica filler in the polymer membrane and the calcium-containing substance in the coated carrier react in the aqueous environment to form the calcium silicate crystal. The polymer membrane generates multiple cracks corresponding to the positions of the calcium silicate crystals. Some cracks penetrate the inner surface and the outer surface, allowing the coated carrier to be released from the inner surface of the polymer membrane to the outer surface through these cracks.

7. The sustained-release coating as described in claim 6, wherein the content of the polymer membrane accounts for 90 to 95 wt% of the total weight of the self-rupturing composite sustained-release membrane, and the content of the self-crystallizing agent accounts for 5 to 10 wt% of the total weight of the self-rupturing composite sustained-release membrane.

8. The sustained-release coating as described in claim 7, wherein the weight ratio of the silica filler to the calcium-containing filler is between 1:1 and 1:

3.

9. The sustained-release coating as described in claim 7, wherein the content of the coated carrier accounts for 85 to 99 wt% of the total weight of the sustained-release coating, and the content of the self-rupturing composite sustained-release membrane accounts for 1 to 15 wt% of the total weight of the sustained-release coating.

10. The slow-release coating as claimed in claim 9, wherein the coated carrier is selected from one of the groups consisting of fertilizer, a soil conditioner, a water treatment agent, and an antibacterial material; wherein the soil conditioner and the water treatment agent each contain the calcium-containing substance; when the coated carrier is selected from fertilizer, the soil conditioner, or the water treatment agent, the content of the self-rupturing composite slow-release membrane accounts for 7 to 15 wt% of the total weight of the slow-release coating; when the coated carrier is selected from the antibacterial material, the content of the self-rupturing composite slow-release membrane accounts for 1 to 2 wt% of the total weight of the slow-release coating.

11. The slow-release coating as described in claim 10, wherein the particle size of the coated carrier is between 2 and 6 mm, the soil conditioner is selected from one or more of the group consisting of lime, microbial agents, organic matter and calcium-containing soil minerals; the water treatment agent is selected from one or more of the group consisting of lime, algaecides, disinfectants and calcium-containing mineral water conditioners; and the antibacterial material is selected from one or more of the group consisting of tea polyphenols, chlorine dioxide and bactericides.

12. The sustained-release coating as described in claim 6, wherein the thickness of the polymeric membrane is between 50 and 200 μm; the polymeric membrane is selected from one or more of the group consisting of acrylic, polyurethane, vinyl acetate-ethylene copolymer and wax.

13. The sustained-release coating as claimed in claim 6, wherein the silica filler is selected from one or more of the group consisting of sodium silicate, potassium silicate and silicon dioxide; and the calcium-containing filler is selected from one or more of the group consisting of calcium hydroxide, calcium chloride and calcium oxide.

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