Seed paper and preparation method and application thereof

Abstract

The invention belongs to the technical field of degradable materials, and provides seed paper as well as a preparation method and application thereof. The seed paper provided by the invention comprises a paper base and a seed layer, and the seed layer comprises a water-soluble natural polysaccharide cross-linked network and seeds. The natural and degradable water-soluble cross-linked polysaccharide can replace industrial glue, the hardness, supporting force and repeated folding resistance of the seed paper are improved, the binding force of the paper base and the seed layer is good, the seed layer is not prone to falling off and peeling, and seeds are distributed and fixed in a water-soluble natural polysaccharide cross-linked network structure and not prone to falling off. When the seed paper is used, when the seed paper is put into water, the water-soluble cross-linked polysaccharide can be rapidly dissolved in water, nutrients are provided for growth of seeds, and the germination efficiency of the seeds is improved. In addition, the raw materials adopted by the seed paper are degradable, safe and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable materials, and more particularly to seed paper and a preparation method and application thereof. Background Art

[0002] Paper-based packaging is very common in various products. Currently, most product packaging materials (such as e-cigarette packaging) are usually made of biodegradable materials, such as biodegradable plastic bags and pure virgin wood pulp.

[0003] Seed paper is a new type of environmentally friendly paper that contains plant seeds. The seed paper can be buried in the soil and waited for it to germinate and grow into a plant. Seed paper can be widely used in various paper designs, such as: tags, business cards, greeting cards, packaging boxes, etc. It is a new type of paper that is both economical and environmentally friendly. The existing seed paper manufacturing process on the market continues the traditional papermaking process. It has problems such as insufficient hardness and easy deformation when supporting heavy objects, which limits the application of seed paper. Coating industrial glue on the surface of seed paper can increase the hardness and support strength of seed paper, but industrial glue generally contains harmful ingredients and cannot be degraded.

[0004] Therefore, there is an urgent need to develop a seed paper with high hardness, high supporting strength, simple preparation process and wide application range. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the aforementioned prior art. To this end, the present invention provides seed paper, its preparation method, and its application. The seed paper provided by the present invention not only has high hardness and support strength, making it less prone to deformation when carrying heavy objects, but also utilizes biodegradable raw materials, eliminating the need for industrial glue and making it more environmentally friendly.

[0006] A first aspect of the present invention provides a seed paper.

[0007] Specifically, a seed paper includes a paper base and a seed layer, wherein the seed layer covers the surface of the paper base, and the seed layer includes: a water-soluble natural polysaccharide cross-linked network and seeds.

[0008] The seed paper provided by the present invention has a two-layer structure, and a seed layer mainly composed of a water-soluble natural polysaccharide cross-linked network is covered on the paper base. As a water-soluble film, on the one hand, the natural and degradable water-soluble cross-linked polysaccharide can replace industrial glue, and the raw materials are safer and more environmentally friendly. On the other hand, covering the seed layer on the paper base can improve the hardness, support force, and resistance to repeated folding of the seed paper, and the bonding force between the paper base and the seed layer is good, and the seed layer is not easy to fall off or peel. The seeds are distributed in the water-soluble natural polysaccharide cross-linked network structure, which not only fixes the seeds, but also the water-soluble cross-linked polysaccharide can quickly dissolve in water, providing nutrients for the growth of the seeds and improving the efficiency of seed germination.

[0009] Preferably, the water-soluble natural polysaccharide is at least one of alginate, water-soluble chitosan, and dextran, and / or the paper base is at least one of kraft paper, cardboard, coated paper, and virgin pulp paper.

[0010] Further preferably, the water-soluble natural polysaccharide is sodium alginate, and / or the paper base is kraft paper. Sodium alginate fertilizer has a significant effect in promoting crop growth and improving the quality and yield of agricultural products.

[0011] Preferably, the seeds are dispersed in the water-soluble natural polysaccharide cross-linked network.

[0012] Preferably, the seeds are at least one of mint leaf seeds, cosmos seeds, and wild flower seeds.

[0013] A second aspect of the present invention provides a method for preparing seed paper.

[0014] A method for preparing seed paper comprises the following steps:

[0015] The water-soluble natural polysaccharide and seeds are mixed and coated on the surface of a paper base, a cross-linking agent is added to cause a cross-linking reaction to form a seed layer, and the mixture is dried to prepare the seed paper.

[0016] Preferably, the water-soluble natural polysaccharide is first prepared into a water-soluble natural polysaccharide solution, and then mixed with the seeds. The mass concentration of the water-soluble natural polysaccharide solution is 1wt%-5wt%.

[0017] Preferably, the water-soluble natural polysaccharide is dissolved in water and stirred at 45-55° C. to dissolve the water-soluble natural polysaccharide to prepare a water-soluble natural polysaccharide solution.

[0018] Preferably, the cross-linking agent is first prepared into a cross-linking agent solution, and then the cross-linking agent is added to cause a cross-linking reaction, wherein the mass concentration of the cross-linking agent solution is 1 wt%-5 wt%.

[0019] Preferably, the ratio of the mass concentration of the water-soluble natural polysaccharide solution to the mass concentration of the cross-linking agent solution is 1:(1-2).

[0020] Further preferably, the ratio of the mass concentration of the water-soluble natural polysaccharide solution to the mass concentration of the cross-linking agent solution is 1:1.

[0021] Preferably, the cross-linking agent is a divalent metal salt.

[0022] More preferably, the cross-linking agent is a calcium salt.

[0023] More preferably, the cross-linking agent is calcium chloride or calcium lactate.

[0024] Preferably, the thickness of the seed layer is greater than 1 mm.

[0025] Further preferably, the seed layer has a thickness of 1-1.5 mm.

[0026] Preferably, the cross-linking agent is added and allowed to stand for 3-10 minutes to allow a cross-linking reaction to occur.

[0027] Preferably, the drying temperature is 25-35° C., and / or the drying time is 1-3 hours.

[0028] A third aspect of the present invention provides a material.

[0029] A material comprising the seed paper, wherein the material is used for packaging or decoration.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The seed paper provided by the present invention comprises a paper base and a seed layer, wherein the seed layer comprises a water-soluble natural polysaccharide cross-linked network and seeds. The natural and degradable water-soluble cross-linked polysaccharide can replace industrial glue, thereby improving the hardness, supporting force, and resistance to repeated folding of the seed paper. The paper base and the seed layer have good bonding force, the seed layer is not easy to fall off or peel, and the seeds are distributed and fixed in the water-soluble natural polysaccharide cross-linked network structure and are not easy to fall off. During use, when the seed paper is put into water, the water-soluble cross-linked polysaccharide can quickly dissolve in water, provide nutrients for the growth of the seeds, and improve the efficiency of seed germination. In addition, the raw materials used in the seed paper of the present invention are degradable, safe, and environmentally friendly. DETAILED DESCRIPTION

[0032] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0033] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0034] The raw materials used in the present invention are:

[0035] Cosmos seeds: purchased from Ouyuan Gardening flagship store.

[0036] Mint leaf seeds: purchased from Ouyuan Gardening flagship store.

[0037] Wildflower seeds: purchased from Ouyuan Gardening flagship store.

[0038] The seeds purchased by the present invention are all easy to germinate, so their germination time is relatively short.

[0039] Example 1

[0040] A seed paper comprising a kraft paper and a seed layer, wherein the seed layer comprises a sodium alginate cross-linked network and mint leaf seeds dispersed in the cross-linked network. The kraft paper (white kraft paper, thickness 0.17 mm) is A4 in size and has a basis weight of 150 g / m 2 .

[0041] A method for preparing seed paper comprises the following steps:

[0042] Take 5g of sodium alginate powder, put it into 100mL of water, and stir it with a magnetic stirrer at a temperature of 50°C and a speed of 610r / min until the solution becomes a transparent gel. Take 1g of mint leaves and seeds and sprinkle them into the sodium alginate solution and stir to obtain a sodium alginate-seed mixed solution. Take 10g of calcium chloride particles and put them into 200mL of water and stir until the calcium chloride is completely dissolved. Take a piece of kraft paper and use a brush to apply a layer of sodium alginate-seed mixed solution on the kraft paper. Then, add the calcium chloride solution dropwise, let it stand for 5 minutes, and then rinse with clean water. The film thickness is 1mm and dried in a 30°C oven for 2 hours to obtain seed paper.

[0043] Example 2

[0044] A seed paper comprising a kraft paper and a seed layer, wherein the seed layer comprises a sodium alginate cross-linked network and cosmos seeds dispersed in the cross-linked network. The kraft paper (white kraft paper, 0.17 mm thick) is A4 in size and has a basis weight of 150 g / m 2 .

[0045] A method for preparing seed paper comprises the following steps:

[0046] Take 3g of sodium alginate powder and place it in 100mL of water. Stir with a magnetic stirrer at 30°C and 610r / min until the solution becomes a transparent gel. Take 1g of cosmos seeds and sprinkle them into the sodium alginate solution and stir. Take 6g of calcium chloride granules and place them in 200mL of water. Stir manually until the calcium chloride is completely dissolved. Take a piece of kraft paper and brush it with a layer of sodium alginate. Use a dropper to add calcium chloride solution, and then exchange sodium and calcium ions. Rinse with clean water until the film thickness reaches 1mm. Dry in a 30°C oven for 2 hours to produce seed paper.

[0047] Example 3

[0048] A seed paper comprising a kraft paper and a seed layer, wherein the seed layer comprises a sodium alginate cross-linked network and wildflower seeds dispersed in the cross-linked network. The kraft paper (white kraft paper, 0.17 mm thick) is A4 in size and has a basis weight of 150 g / m 2 .

[0049] A method for preparing seed paper comprises the following steps:

[0050] Take 1g of sodium alginate powder and place it in 100mL of water. Stir with a magnetic stirrer at 30°C and 610r / min until the solution becomes a transparent gel. Sprinkle 1g of wildflower seeds into the sodium alginate solution and stir. Take 3g of calcium chloride granules and place them in 200mL of water. Stir manually until the calcium chloride is completely dissolved. Take a piece of kraft paper and apply a layer of sodium alginate with a brush. Use a dropper to add calcium chloride solution and rinse with clean water until the film thickness reaches 1mm. Dry in a 30°C oven for 2 hours to produce seed paper.

[0051] Comparative Example 1

[0052] This comparative example is commercially available seed paper purchased from Youteng Paper Products, which contains mint leaf seeds.

[0053] Comparative Example 2

[0054] This comparative example is commercially available seed paper purchased from Youteng Paper Products, which contains cosmos seeds.

[0055] Comparative Example 3

[0056] This comparative example is commercially available seed paper purchased from Youteng Paper Products, which contains wildflower seeds.

[0057] Comparative Example 4

[0058] This comparative example differs from Example 1 in that sodium alginate is replaced with polyvinyl alcohol (PVA). The preparation method is as follows: 20g of PVA is added to 80g of deionized water and dissolved using a magnetic stirrer until no granular crystals remain in the liquid. Mint seeds are added and mixed thoroughly, and the mixture is then coated on a kraft paper surface to a thickness of approximately 0.3±0.2mm. The mixture is then dried in an oven at 30°C for 2 hours to produce seed paper.

[0059] Product effect testing

[0060] 1. Support strength test: Cut the seed paper into 10×5cm pieces, fold them 2cm away from the two ends, and then stand them on the table to form a platform. Add a 3g weight on the platform, and then increase it to 5g, 8g, 10g... until it collapses.

[0061] Table 1 Supporting force of each embodiment and comparative example

[0062] Bearing weight (g) Test results Example 1 10 No collapse Example 2 10 No collapse Example 3 10 No collapse Comparative Example 1 3 collapse Comparative Example 2 3 collapse Comparative Example 3 3 collapse

[0063] As shown in the table above, the seed paper produced by the present invention can withstand significantly greater weight than the three types of seed paper purchased in Comparative Examples 1-3, demonstrating its greater hardness and superior support. On the one hand, the present invention enhances the load-bearing capacity of the seed paper by coating the kraft paper base with a layer of sodium alginate containing seeds. On the other hand, commercially available seed paper is made from pure cotton or pure wood pulp that is naturally air-dried, resulting in a significantly weaker hardness than the kraft paper base used in the present invention.

[0064] 2. Repeated Folding Test: The seed paper was folded repeatedly, with the same crease repeated 500 times. A 2cm thick aluminum block with a radius of 2cm was used to rub the coated surface of the paper repeatedly for 5 minutes.

[0065] Experimental results showed that the seed paper produced in Examples 1-3 of the present invention showed no signs of shedding, peeling, or breaking after 500 cycles, demonstrating good adhesion between the coating and the kraft paper. In contrast, the seed paper purchased in Comparative Examples 1-3 exhibited fine linting. The seed paper in Comparative Example 4 exhibited cracking in both the paper and the film after a single folding test. This is due to the addition of PVA, which reduced the seed paper's flexibility and made it brittle.

[0066] 3. Seed Germination Time Test: Equal-sized seed papers from each example and comparative example were shredded into similar sizes and placed in paper cups. Water of equal mass was added, with the water level being aligned with the highest point of the paper in the cup. The seeds were placed in the same environment (ambient temperature of 24°C, humidity of 50%-67%, indoor germination), and the germination of the seeds was observed. "Germination" in this context refers to the phenomenon in which the seeds have not fully broken through the shell, but have developed thin, short sprouts.

[0067] Table 2 Seed germination of each embodiment and comparative example

[0068] Paper type Seed types Seed layer dissolution time Germination time Example 1 mint leaves and seeds About 5 minutes 3 days Comparative Example 1 mint leaves and seeds / More than 5 days Example 2 Cosmos seeds About 5 minutes 4 days Comparative Example 2 Cosmos seeds / More than 7 days Example 3 wildflower seeds About 5 minutes 17h Comparative Example 3 wildflower seeds / More than 3 days Comparative Example 4 mint leaves and seeds About 30 minutes No germination for more than 5 days

[0069] As can be seen from the results in the above table, the seed layer dissolution time of the seed paper provided by Examples 1-3 of the present invention is short, and the seed germination time is much shorter than that of the seed paper purchased in Comparative Examples 1-3.

[0070] The seed paper process of Comparative Examples 1-3 is a pulp wrapping or two-paper sandwich process, so there is no film and no film dissolution time.

[0071] In Comparative Example 4, sodium alginate is replaced with polyvinyl alcohol. Not only does the dissolution time of the seed layer take a long time and the dissolution speed is slow, but the germination time is also much longer than that of the seed paper provided in Examples 1-3 of the present invention.

Claims

1. A seed paper, characterized in that: The invention comprises a paper base and a seed layer, wherein the seed layer covers the surface of the paper base and comprises a water-soluble natural polysaccharide cross-linked network and seeds.

2. The seed paper according to claim 1, characterized in that The water-soluble natural polysaccharide is at least one of alginate, water-soluble chitosan, and dextran; and / or the paper base is at least one of kraft paper, cardboard, coated paper, and raw pulp paper.

3. The seed paper according to claim 1, characterized in that The seeds are dispersed in the water-soluble natural polysaccharide cross-linked network.

4. A method for preparing seed paper, characterized in that: The steps include: The water-soluble natural polysaccharide and seeds are mixed and coated on the surface of a paper base, a cross-linking agent is added to cause a cross-linking reaction to form a seed layer, and the mixture is dried to prepare the seed paper.

5. The preparation method according to claim 4, characterized in that The water-soluble natural polysaccharide is first prepared into a water-soluble natural polysaccharide solution, which is then mixed with the seeds. The mass concentration of the water-soluble natural polysaccharide solution is 1wt%-5wt%.

6. The preparation method according to claim 4, characterized in that The cross-linking agent is first prepared into a cross-linking agent solution, and then the cross-linking agent is added to cause a cross-linking reaction. The mass concentration of the cross-linking agent solution is 1wt%-5wt%.

7. The preparation method according to claim 5 or 6, characterized in that: The ratio of the mass concentration of the water-soluble natural polysaccharide solution to the mass concentration of the cross-linking agent solution is 1:(1-2).

8. The preparation method according to claim 4, characterized in that The cross-linking agent is a divalent metal salt.

9. The preparation method according to claim 4, characterized in that The cross-linking agent is added and allowed to stand for 3-10 minutes to allow a cross-linking reaction to occur.

10. A material, characterized in that The seed paper according to any one of claims 1 to 3, wherein the material is used for packaging or decoration.