A high air permeability functional paper-based material and preparation method thereof

Abstract

The present invention relates to a paper-based material and a preparation method thereof, and in particular to a highly air-permeable functional paper-based material and a preparation method thereof. In the present invention, molecular sieves are mixed with polyamide to prepare synthetic fibers, which are then mixed with cellulose fibers for pulping to prepare paper-based materials. The molecular sieves are fixed in the fibers by utilizing the wrapping property of the fibers, thereby avoiding the problem of molecular sieve falling off. Moreover, the presence of the molecular sieves in the synthetic fibers improves the air permeability of the synthetic fibers, thereby avoiding their barrier effect on gas, thereby improving the air permeability of the paper-based materials while ensuring the strength of the paper-based materials.

Description

Technical Field

[0001] The invention relates to a paper-based material and a preparation method thereof, and in particular to a high-air-permeability functional paper-based material and a preparation method thereof. Background Art

[0002] Packaging paper is widely used in many fields, such as cement and fertilizer. These fields have high requirements for the air permeability of packaging paper to improve production efficiency, ensure the balance of air pressure inside and outside the packaging, and prevent problems such as broken and bulging packages. Especially in the field of cement packaging, there are strict requirements on the air permeability and strength of paper bags during the rapid filling process.

[0003] In the prior art, adding synthetic fibers to cellulose fiber pulp is a common technical means to improve the tensile strength and tear strength of paper. However, excessive addition of synthetic fibers will occupy the gaps between cellulose fibers, resulting in a decrease in air permeability. In addition, adding molecular sieves to pulp is also a common means to improve the air permeability of paper, but for high air permeability applications, molecular sieves are easily detached with the flow of air, resulting in a decrease in stability. Therefore, how to achieve the above problems at the same time is a difficult problem. Summary of the invention

[0004] The present invention proposes a new functional paper-based material with high air permeability and a preparation method thereof, wherein the molecular sieve is fixed in the fiber by spinning molecular sieve and fiber polymer simultaneously to prepare synthetic fiber, and then mixed with cellulose fiber for pulping to prepare paper-based material, thereby avoiding the problem of molecular sieve falling off; moreover, the presence of molecular sieve in synthetic fiber improves the air permeability of synthetic fiber, avoids its barrier effect on gas, and thus improves the air permeability of paper-based material.

[0005] Specifically, the present invention provides a highly air-permeable functional paper-based material, which includes cellulose fibers, synthetic fibers and molecular sieves as fillers, wherein the content of the synthetic fibers is 10-20wt%, the content of the molecular sieves is 3-10wt%, the molecular sieves are doped into the synthetic fibers, and the synthetic fibers are formed by doping the molecular sieves into a spinning solution and then spinning.

[0006] Specifically, the cellulose fibers include natural cellulose fibers and regenerated cellulose fibers.

[0007] Specifically, the synthetic fiber is a polyamide fiber with a molecular weight of 5000-50000.

[0008] Specifically, the molecular sieve is a microporous molecular sieve, specifically selected from one or more of 3A, 4A, 5A or Y-type molecular sieves.

[0009] Specifically, the molecular sieve is a molecular sieve modified by a silane coupling agent APTES.

[0010] Specifically, the length of the synthetic fiber is 2 to 8 mm, and the linear density is 0.1 to 1.0 dtex; the length of the cellulose fiber is 3 to 10 mm, and the linear density is 0.2 to 1.1 dtex.

[0011] The present invention also provides a method for preparing a high-air permeability functional paper-based material, which comprises the following steps:

[0012] (1) Dissolving low molecular weight polyamide in an organic solvent, and sequentially adding a surfactant and a molecular sieve into the organic solution, and stirring the solution to form a uniform spinning solution;

[0013] (2) taking the spinning solution in step (1) and spinning it through a spinning head to obtain synthetic fibers;

[0014] (3) The shredded synthetic fibers and cellulose fibers are subjected to paddle mixing, paddle punching, papermaking, pressing and dehydration, sizing, and drying to obtain a highly air-permeable functional paper-based material.

[0015] Specifically, the organic solvent is one of dimethylformamide, dimethylacetyl, acetone and ethanol, the content of polyamide in the spinning solution is 5-15wt%, and the content of molecular sieve is 1-10wt%.

[0016] Specifically, the surfactant is selected from anionic surfactants, and its content is 0.5-2wt%.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] First, the present invention mixes molecular sieve with polyamide to prepare synthetic fibers, which are then mixed with cellulose fibers for pulping to prepare paper-based materials. The molecular sieve is fixed in the fibers by utilizing the wrapping property of the fibers, thereby avoiding the problem of molecular sieve falling off. Moreover, the presence of the molecular sieve in the synthetic fibers improves the air permeability of the synthetic fibers, thereby avoiding its barrier effect on gases, thereby improving the air permeability of the paper-based materials while ensuring the strength of the paper-based materials.

[0019] Secondly, the present invention uses low molecular weight polyamide as the fiber material, which ensures that the polyamide fiber contains abundant terminal carboxyl groups. Combined with the amino-modified molecular sieve, the retention rate of the molecular sieve in the synthetic fiber is further improved, and the bonding strength between the molecular sieve and the fiber is also improved.

[0020] In addition, the present invention uses a microporous molecular sieve, which can adsorb water molecules and other small molecules, and its strong adsorption capacity helps to remove excess water and impurities in the paper-based material, thereby improving the air permeability of the material. Moreover, the high specific surface area of ​​the microporous molecular sieve increases its contact area with the surrounding substances, thereby improving the adsorption and air permeability efficiency. DETAILED DESCRIPTION

[0021] Example 1: This example adopts the following steps to prepare a highly air permeable functional paper-based material:

[0022] (1) Polyamide with a molecular weight of 10,000 (12 wt%) was dissolved in dimethylformamide, and sodium dodecylbenzene sulfonate (0.5 wt%) and Y-type molecular sieve with a particle size of 700 nm (unmodified, 5 wt%) were added to the organic solution in sequence, and stirred to form a uniform spinning solution;

[0023] (2) The spinning solution in step (1) is spun through a spinning head to obtain synthetic fibers, and the fibers are chopped to have an average length of 3 mm and a linear density of 0.5 dtex;

[0024] (3) Take 5mm hardwood fiber with a linear density of 1.7dtex, mix it with synthetic fiber in a mass ratio of 4:1, and then go through paddle preparation, paddle punching, papermaking, pressing and dehydration, sizing, and drying to obtain a highly air-permeable functional paper-based material. According to spectrophotometric testing, the synthetic fiber content in the product paper-based material is 15wt%, and the molecular sieve content is 4.5%.

[0025] Example 2: This example adopts the following steps to prepare a highly air permeable functional paper-based material:

[0026] (1) Polyamide with a molecular weight of 10,000 (12 wt%) was dissolved in dimethylformamide, and sodium dodecylbenzene sulfonate (0.5 wt%) and 3A molecular sieve with a particle size of 450 nm (unmodified, 5 wt%) were added to the organic solution in sequence, and stirred to form a uniform spinning solution;

[0027] (2) The spinning solution in step (1) is spun through a spinning head to obtain synthetic fibers, and the fibers are chopped to have an average length of 3 mm and a linear density of 0.5 dtex;

[0028] (3) Take 5mm hardwood fiber with a linear density of 1.7dtex, mix it with synthetic fiber in a mass ratio of 4:1, and then go through paddle preparation, paddle punching, papermaking, pressing and dehydration, sizing, and drying to obtain a highly air-permeable functional paper-based material. According to spectrophotometric testing, the synthetic fiber content in the product paper-based material is 15wt%, and the molecular sieve content is 4.6%.

[0029] Example 3: This example adopts the following steps to prepare a highly air permeable functional paper-based material:

[0030] (1) Polyamide with a molecular weight of 10,000 (12 wt%) was dissolved in dimethylformamide, and sodium dodecylbenzene sulfonate (0.5 wt%) and Y-type molecular sieve with a particle size of 700 nm (the molecular sieve was modified by silane coupling agent APTES, 5 wt%) were added to the organic solution in sequence, and stirred to form a uniform spinning solution;

[0031] (2) The spinning solution in step (1) is spun through a spinning head to obtain synthetic fibers, and the fibers are chopped to have an average length of 3 mm and a linear density of 0.5 dtex;

[0032] (3) Take 5mm hardwood fiber with a linear density of 1.7dtex, mix it with synthetic fiber in a mass ratio of 4:1, and then go through paddle preparation, paddle punching, papermaking, pressing and dehydration, sizing, and drying to obtain a highly air-permeable functional paper-based material. According to spectrophotometric testing, the synthetic fiber content in the product paper-based material is 14.8wt%, and the molecular sieve content is 5.8%.

[0033] Comparative Example 1: This comparative example adopts the following steps to prepare a highly air permeable functional paper-based material:

[0034] (1) polyamide with a molecular weight of 10,000 (12 wt%) was dissolved in dimethylformamide to form a uniform spinning solution;

[0035] (2) The spinning solution in step (1) is spun through a spinning head to obtain synthetic fibers, and the fibers are chopped to have an average length of 3 mm and a linear density of 0.5 dtex;

[0036] (3) Take 5mm hardwood fiber with a linear density of 1.7dtex, mix it with synthetic fiber at a mass ratio of 4:1, and continue to add Y-type molecular sieve at a mass ratio of 12:5 to polyamide, and then obtain a highly air-permeable functional paper-based material after paddle preparation, paddle punching, papermaking, pressing and dehydration, sizing, and drying. According to spectrophotometry, the synthetic fiber content in the product paper-based material is 15.3wt%, and the molecular sieve content is 4.0%.

[0037] Comparative Example 2: This example adopts the following steps to prepare a highly air-permeable functional paper-based material:

[0038] (1) Polyamide with a molecular weight of 10,000 (12 wt%) was dissolved in dimethylformamide, and sodium dodecylbenzene sulfonate (0.5 wt%) and MCM-41 molecular sieve with a particle size of 800 nm (unmodified, 5 wt%) were added to the organic solution in sequence, and stirred to form a uniform spinning solution;

[0039] (2) The spinning solution in step (1) is spun through a spinning head to obtain synthetic fibers, and the fibers are chopped to have an average length of 3 mm and a linear density of 0.5 dtex;

[0040] Take 5mm hardwood fiber with a linear density of 1.7dtex, mix it with synthetic fiber at a mass ratio of 4:1, and then go through paddle preparation, paddle punching, papermaking, pressing and dehydration, sizing, and drying to obtain a highly air-permeable functional paper-based material. According to spectrophotometry, the synthetic fiber content in the product paper-based material is 15.1wt%, and the molecular sieve content is 4.4%.

[0041] The molecular sieves of the above examples and comparative examples were tested for performance, and the results are shown in the following table:

[0042]

[0043] It can be seen from the above results that the high air permeability functional paper-based material prepared by the present invention can significantly improve the air permeability while ensuring the strength, and has a high application value.

Claims

1. A high air permeability functional paper-based material, characterized in that The paper-based material includes cellulose fiber, synthetic fiber and molecular sieve as filler, wherein the content of the synthetic fiber is 10-20wt%, the content of the molecular sieve is 3-10wt%, the molecular sieve is doped in the synthetic fiber, and the synthetic fiber is formed by doping the molecular sieve in the spinning solution and then spinning; the cellulose fiber includes natural cellulose fiber and regenerated cellulose fiber; the synthetic fiber is polyamide fiber, whose molecular weight is 5000-50000, and the polyamide fiber has terminal carboxyl groups; the molecular sieve is a microporous molecular sieve, specifically selected from one or more of 3A, 4A, 5A or Y-type molecular sieves, and the particle size is 100nm-2μm; the molecular sieve is a molecular sieve modified by a silane coupling agent APTES.

2. The paper-based material according to claim 1, characterized in that The length of the synthetic fiber is 2-8 mm, and the linear density is 0.1-1.0 dtex; the length of the cellulose fiber is 3-10 mm, and the linear density is 0.2-1.1 dtex.

3. A method for preparing a highly air-permeable functional paper-based material according to claim 1, characterized in that The steps include: (1) Dissolving low molecular weight polyamide in an organic solvent, and sequentially adding a surfactant and a molecular sieve into the organic solution, and stirring the solution to form a uniform spinning solution; (2) taking the spinning solution in step (1) and spinning it through a spinning head to obtain synthetic fibers; (3) The shredded synthetic fibers and cellulose fibers are pulped, punched, paper-made, pressed and dehydrated, sizing, and dried to obtain a highly air-permeable functional paper-based material.

4. The preparation method according to claim 3, characterized in that The organic solvent is one of dimethylformamide, acetone and ethanol. The content of polyamide in the spinning solution is 5-15wt%, and the content of molecular sieve is 1-10wt%.

5. The preparation method according to claim 3, characterized in that The surfactant is selected from anionic surfactants, and its content is 0.5-2wt%.

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