Cellulose paper with high air permeability and no wrinkling as well as preparation method and application of cellulose paper

Abstract

The invention relates to high-air-permeability non-wrinkling cellulose paper as well as a preparation method and application thereof. The preparation method of the high-air-permeability non-wrinkling cellulose paper comprises the following steps: S1, preparing pulp from paper pulp dried by a drying cylinder, flash drying pulp, mercerizing pulp, chemical fibers and water; s2, carrying out in-pulp sizing on the pulp obtained in the step S1, and then forming, dehydrating and drying to obtain raw paper; and S3, carrying out surface sizing on the raw paper in the step S2, and drying to obtain the cellulose paper. The cellulose paper prepared by the preparation method can reach high thickness without transverse wrinkling treatment, is good in air permeability, small in suction resistance and good in suction resistance stability, and meets the requirements for preparing groove filter sticks.

Description

Technical Field

[0001] The present invention relates to the technical field of tobacco filter materials, and more specifically to a high-air-permeability wrinkle-free cellulose paper and a preparation method and application thereof. Background Art

[0002] In recent years, the tobacco industry has continuously put forward new requirements for the harm reduction and tar reduction of cigarettes. The grooved filter rod has the characteristics of high tar interception efficiency and novel appearance, so its application in harm reduction and tar reduction has expanded rapidly. Cellulose paper is the key component material of the grooved filter rod, and plant fiber is generally used as the main raw material. Compared with acetate fiber tow, cellulose paper has good air permeability and large specific surface area, and its surface hydrophilicity is high, so it has higher adsorption performance and filtration efficiency.

[0003] After the grooves are pressed, the cellulose paper is rolled together with the forming paper and acetate fiber tow to form a groove filter rod. The grooves of the groove filter rod are formed between the cellulose paper and the forming paper surface. When the cigarette is smoked, the mainstream smoke from the filter rod partially penetrates the cellulose paper and flows out from the groove to the end of the suction. Due to the porous structure of cellulose paper and the excellent adsorption performance of plant fibers, the particulate matter in the mainstream smoke that penetrates the cellulose paper is filtered and adsorbed by the fibers in the cellulose paper, which has a high efficiency in reducing tar.

[0004] The main performance indicators of cellulose paper include basis weight, air permeability, thickness and longitudinal tensile strength. Basis weight will significantly affect the pressure drop of the groove filter rod. Generally speaking, the higher the basis weight, the greater the pressure drop. Air permeability will affect the adsorption and filtration capacity of the groove filter rod for tar, and will also affect the pressure drop of the filter rod. Sufficient thickness ensures that the cellulose paper is not crushed during the groove pressing process, while ensuring the groove depth and shape to ensure that the smoke passing efficiency and appearance meet the design requirements. Good longitudinal tensile strength is mainly to ensure the performance of the cellulose paper on the machine and prevent it from being crushed.

[0005] At present, the cellulose paper used in the industry is cellulose paper with irregular transverse wrinkles after transverse wrinkling treatment. The transverse wrinkling treatment is mainly to increase the thickness of the cellulose paper, and at the same time to assist in improving the transverse interception ability of the grooved filter rod for smoke components. However, the internal structure of the cellulose paper after the transverse wrinkling treatment is dense, and the three-dimensional thickness is uneven; among them, the dense internal structure of the paper leads to a decrease in the amount of mainstream smoke penetrating the cellulose paper and a decrease in the adsorption efficiency, while the uneven three-dimensional thickness leads to uneven air permeability between the forming paper and the cellulose paper of the grooved filter rod, resulting in unstable suction resistance of the grooved filter rod. And when the mainstream smoke passes through the gap between the forming paper and the cellulose paper, the particulate matter in the smoke only undergoes inertial collision and diffusion deposition on the surface of the paper, and the interception and adsorption efficiency is low, and the cigarette smoke release and taste are not ideal. In addition, the cellulose paper used in the industry also has the problem of low air permeability, and its air permeability is usually around 1000cm3 / (min·cm 2 )the following.

[0006] In order to solve the problems existing in the cellulose paper after the above-mentioned transverse corrugation treatment, the industry has tried to develop cellulose paper that does not require transverse corrugation treatment, but this cellulose paper needs to have a high basis weight to meet its thickness requirements, but the high basis weight further reduces the air permeability of the cellulose paper; and the internal structure of this cellulose paper is dense, and the suction resistance is too large after it is made into a grooved filter rod.

[0007] Therefore, it is necessary to solve the problem that the current cellulose paper has a great negative impact on the suction resistance, retention and adsorption of the groove filter rod after the transverse corrugation treatment, or the cellulose paper that does not require transverse corrugation treatment has low air permeability due to high quantitative and high suction resistance due to dense internal structure. Summary of the invention

[0008] The primary purpose of the present invention is to overcome the above-mentioned problems in the prior art and provide a method for preparing cellulose paper with high air permeability and no wrinkles.

[0009] A further object of the present invention is to provide a cellulose paper having high air permeability and which does not wrinkle.

[0010] A further object of the present invention is to provide the use of the above cellulose paper in preparing a grooved filter rod.

[0011] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0012] A method for preparing high-permeability wrinkle-free cellulose paper comprises the following steps:

[0013] S1. The pulp is dried by cylinder, flash dried pulp, mercerized pulp, chemical fiber and water to make pulp;

[0014] S2. performing internal sizing on the slurry in step S1, and then obtaining base paper after forming, dehydrating and drying;

[0015] S3. Surface sizing the base paper in step S2 and drying the base paper to obtain the cellulose paper;

[0016] The mass ratio of the cylinder dried pulp, flash dried pulp, mercerized pulp and chemical fiber in step S1 is (0.2-1): (1-3.2): (1.2-5): (0-0.2).

[0017] The preparation method of the present invention adds a certain amount of mercerized pulp to the cylinder-dried pulp, and the cylinder-dried pulp is the basic component of cellulose paper, which provides basic strength and ensures the normal production of cellulose paper without paper interruption. Mercerized pulp has good air permeability, which can improve the air permeability of cellulose paper, reduce the suction resistance of cellulose paper, and enable cellulose paper to reach a high thickness without transverse wrinkling treatment; however, the dispersibility of mercerized pulp is poor and the paper strength is low, which will cause the cellulose paper to be unable to be rolled into shape and then made into a groove filter rod, or the suction resistance after being made into a groove filter rod is unstable.

[0018] A certain amount of flash dried pulp is further added. The addition of flash dried pulp is conducive to the dispersion of mercerized pulp and cooperates with the sizing in the pulp to improve the strength of cellulose paper, so that the cellulose paper can be rolled into a groove filter rod; in addition, since the addition of flash dried pulp is conducive to the dispersion of mercerized pulp, the stability of the suction resistance of the cellulose paper after being made into a groove filter rod can be guaranteed. Do not add too much flash dried pulp, otherwise the air permeability of the cellulose paper will decrease.

[0019] That is, the preparation method of the present invention uses cylinder drying pulp, flash drying pulp and mercerized pulp and their dosage, as well as sizing in the pulp, so that the prepared cellulose paper can achieve high thickness without transverse wrinkling treatment, and has good air permeability, low suction resistance, and good suction resistance stability, thus meeting the requirements for preparing grooved filter rods.

[0020] It should be understood that the cylinder dried pulp of the present invention refers to the pulp obtained after wet pulp is squeezed and dehydrated and then dried by cylinder drying, which is a conventional drying method for pulp. The flash dried pulp of the present invention refers to the pulp obtained after wet pulp is flash dried.

[0021] In the present invention, the amount of cylinder dried pulp in step S1 can be specifically 0.2, 0.5, 0.8 or 1 weight part, the amount of flash dried pulp can be specifically 1, 1.5, 1.8, 2.0, 2.5, 2.8, 3.0 or 3.2 weight parts, and the amount of mercerized pulp can be specifically 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 or 5 weight parts.

[0022] Preferably, in step S1, the ratio of the sum of the mass of the cylinder-dried pulp, flash-dried pulp, mercerized pulp and chemical fiber to the mass of water is 1:(18-20).

[0023] Preferably, the cylinder dried pulp in step S1 is at least one of hardwood pulp, softwood pulp, bagasse pulp, hemp pulp, straw pulp or bamboo pulp.

[0024] Preferably, the average fiber length of the flash dried pulp in step S1 is 1.0-1.8 mm, the average fiber width is 20.0-27.0 um, the average fiber thickness is 0.10-0.18 mg / m, and the torsion index is 20.0-30.0%.

[0025] More preferably, the average fiber length of the flash dried pulp in step S1 is 1.5-1.7 mm, the average fiber width is 23.5-24.5 μm, the average fiber thickness is 0.14-0.17 mg / m, and the fiber twist index is 20.0-25.0%. When the parameters are controlled within this range, the obtained cellulose paper has better air permeability, lower absorption resistance, and greater thickness at the same weight.

[0026] Preferably, the average length of the mercerized pulp fibers in step S1 is 2.5-2.8 mm, the average width is 27.0-30.0 um, the average thickness is 0.12-0.18 mg / m, and the twist index is 20%-35%.

[0027] Preferably, the chemical fiber in step S1 is at least one of viscose fiber, modal fiber, lyocell fiber, polyvinyl alcohol fiber or polylactic acid fiber.

[0028] Preferably, the average length of the chemical fiber in step S1 is 4-6 mm, and the linear density is 2.0-3.5 dtex.

[0029] Preferably, the process parameters for preparing the slurry in step S1 are: pulping concentration of 4.0-6.0%, and pulping time of 30-60 min.

[0030] Preferably, the beating degree of the slurry in step S1 is 12-40° SR.

[0031] Preferably, the mass ratio of the internal sizing agent used for the internal sizing in step S2 to the fibers in the slurry is (1-8):(92-99).

[0032] More preferably, the sizing agent in the slurry is at least one of polyamide epichlorohydrin resin, polyvinyl alcohol, starch, guar gum, polyethyleneimine or phenolic resin; the starch includes but is not limited to at least one of dialdehyde starch and cationic starch.

[0033] Preferably, the mass ratio of the surface sizing agent used for the surface sizing in step S3 to the base paper is (0.2-4):100.

[0034] More preferably, the surface sizing agent is at least one of starch, polyvinyl alcohol, polyethylene glycol, acrylate, alkyl ketene dimer or carboxymethyl cellulose.

[0035] A high-air-permeability wrinkle-free cellulose paper is prepared by the preparation method.

[0036] Preferably, the basis weight of the cellulose paper is 80 to 90 g / m 2 .

[0037] The use of the above cellulose paper in the preparation of grooved filter rods also falls within the protection scope of the present invention.

[0038] Preferably, the cellulose paper is used as forming paper in the preparation of a grooved filter rod.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The cellulose paper prepared by the preparation method of the present invention can achieve high thickness without transverse wrinkling treatment, and has good air permeability, small suction resistance and good suction resistance stability, thus meeting the requirements for preparing groove filter rods. DETAILED DESCRIPTION

[0041] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0042] Example 1

[0043] This embodiment provides a method for preparing a cellulose paper with high air permeability and no wrinkles, comprising the following steps:

[0044] 1) softwood pulp, flash dried pulp (average fiber length of 1.5 mm, average width of 23.5 μm, average thickness of 0.14 mg / m, twist index of 24.1%), mercerized pulp (average fiber length of 2.6 mm, average width of 29.2 μm, average thickness of 0.17 mg / m, twist index of 32.6%), viscose fiber (linear density of 3.5 dtex, average length of 6 mm) and water were uniformly mixed in a mass ratio of 1:1:5:0.1:134.9 to prepare a pulp; the beating degree of the pulp was 13°SR;

[0045] 2) adding a polyamide epichlorohydrin resin solution having a concentration of 15 wt % to the slurry obtained in step 1), mixing them evenly, and then forming the paper on a paper machine, pressing and dehydrating the paper, and drying the paper to obtain base paper; wherein the mass ratio of the polyamide epichlorohydrin resin in the polyamide epichlorohydrin resin solution to the fiber in the slurry is 4:96;

[0046] 3) The base paper obtained in step 2) is subjected to surface sizing treatment with an acrylic acid ester solution, and then dried to obtain cellulose paper, wherein the acrylic acid ester used for surface sizing treatment accounts for 0.2 wt% of the cellulose paper.

[0047] Example 2

[0048] This embodiment provides a method for preparing cellulose paper with high air permeability and no wrinkles, which is basically the same as that of embodiment 1, except that:

[0049] In the first step, the softwood pulp was replaced by hemp pulp; the viscose fiber was replaced by polyvinyl alcohol fiber (linear density of 3.0 dtex, average length of 5 mm); the mass ratio of softwood pulp, flash dried pulp, mercerized pulp, polyvinyl alcohol fiber and water was 1:3:2:0.1:115.9; the beating degree of the pulp was 15°SR;

[0050] 2) replacing the polyamide epichlorohydrin resin solution with a dialdehyde starch solution; wherein the mass ratio of the dialdehyde starch in the dialdehyde starch solution to the fiber in the dialdehyde starch solution is 8:92;

[0051] 3) The acrylic acid ester solution is replaced by carboxymethyl cellulose solution, and the base paper obtained in step 2) is subjected to surface sizing treatment, and then dried to obtain cellulose paper, wherein the carboxymethyl cellulose subjected to surface sizing treatment accounts for 4 wt % of the cellulose paper.

[0052] Example 3

[0053] This embodiment provides a method for preparing a cellulose paper with high air permeability and no wrinkles, comprising the following steps:

[0054] 1) softwood pulp, flash dried pulp (average fiber length of 1.5 mm, average width of 23.5 μm, average thickness of 0.14 mg / m, twist index of 24.1%), mercerized pulp (average fiber length of 2.6 mm, average width of 29.2 μm, average thickness of 0.17 mg / m, twist index of 32.6%), lyocell fiber (2.0 dtex, 4 mm) and water were uniformly mixed in a mass ratio of 0.2:3.2:1.2:0.2:91.2 to prepare a slurry; the beating degree of the slurry was 12°SR;

[0055] 2) adding a polyamide epichlorohydrin resin solution having a concentration of 15 wt % to the slurry obtained in step 1), mixing them evenly, and then forming the paper on a paper machine, pressing and dehydrating the paper, and drying the paper to obtain base paper; wherein the mass ratio of the polyamide epichlorohydrin resin in the polyamide epichlorohydrin resin solution to the fiber in the slurry is 4:96;

[0056] 3) The base paper obtained in step 2) is subjected to surface sizing treatment with a polyvinyl alcohol solution, and then dried to obtain cellulose paper, wherein the polyvinyl alcohol used for surface sizing treatment accounts for 0.2 wt% of the cellulose paper.

[0057] Example 4

[0058] This embodiment provides a method for preparing highly air-permeable wrinkle-free cellulose paper, which is basically the same as that of Embodiment 3, except that: in step 1), the average fiber length of the flash-dried pulp is 1.2 mm, the average width is 22.5 um, the average thickness is 0.11 mg / m, and the twist index is 28.2%.

[0059] Example 5

[0060] This embodiment provides a method for preparing highly air-permeable wrinkle-free cellulose paper, which is basically the same as that of Embodiment 3, except that: in step 1), the average fiber length of the flash-dried pulp is 1.7 mm, the average width is 24.5 um, the average thickness is 0.17 mg / m, and the twist index is 20.0%.

[0061] Example 6

[0062] This embodiment provides a method for preparing high-permeability wrinkle-free cellulose paper, which is basically the same as Example 3, except that: in step 1), the average fiber length of the mercerized pulp is 2.7 mm, the average width is 27.3 um, the average thickness is 0.13 mg / m, and the twist index is 20.9%.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing high-permeability wrinkle-free cellulose paper, which is basically the same as Example 3, except that: in step 1), no flash-dried pulp is added.

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing cellulose paper, which is basically the same as Example 3, except that: in step 1), softwood pulp, flash dried pulp, mercerized pulp, viscose fiber and water are uniformly mixed in a mass ratio of 0.2:8:1.2:0.2:182.4.

[0067] Comparative Example 3

[0068] This comparative example provides a method for preparing cellulose paper, which is basically the same as Example 3, except that: in step 1), no mercerized pulp is added.

[0069] Comparative Example 4

[0070] This comparative example provides a method for preparing cellulose paper, which is basically the same as Example 3, except that: in step 1), softwood pulp, flash dried pulp, mercerized pulp, viscose fiber and water are uniformly mixed in a mass ratio of 0.2:3.2:8:0.2:220.4.

[0071] Comparative Example 5

[0072] This comparative example provides a method for preparing cellulose paper, which is basically the same as Example 3, except that: in step 2), no polyamide epichlorohydrin resin solution is added, that is, no internal sizing is performed.

[0073] Comparative Example 6

[0074] This comparative example provides a method for preparing cellulose paper, comprising the following steps: conveying the prepared pulp (softwood pulp, flash dried pulp and water mixed in a mass ratio of 2:1:57) to a wire section for dehydration and forming on a forming wire, the formed paper web is subjected to pressing and dehydration, and then enters a scraper corrugation process, and the corrugated paper web is dried to obtain corrugated cellulose paper.

[0075] Performance Testing

[0076] The cellulose paper of each embodiment and comparative example was tested:

[0077] (1) Cellulose paper performance test

[0078] The basis weight of paper is determined according to GB / T 451.2-2023, the air permeability of paper is determined according to GB / T 23227-2018, the tensile strength of paper is determined according to GB / T 12914-2018, and the thickness of paper is determined according to GB / T 451.3-2002.

[0079] (2) Test on suction resistance of filter rod made of cellulose paper

[0080] Each cellulose paper was used in a filter rod forming machine with the same process parameters and the same tow to make a grooved filter rod. The parameter requirements of the grooved filter rod were: length 100 mm, circumference 24.05 mm, groove depth 0.4 mm, and number of grooves 16. The grooved filter rod was tested for draw resistance and draw resistance COV using a filter rod draw resistance tester according to GB / T 2238 Determination of physical properties of cigarettes and filter rods Part 5 Cigarette draw resistance and filter rod pressure drop, and the data obtained are shown in Table 1 below.

[0081] Table 1

[0082]

[0083]

[0084] From Table 1, we can see that:

[0085] Examples 1 to 6 ensure that the cellulose paper has a high thickness (above 160 μm) at a high quantitative condition, and the air permeability of the cellulose paper reaches 1100 cm 3 / (min·cm 2 ), the suction resistance is all below 3000Pa, and the suction resistance COV is all below 3.0%, indicating that the cellulose paper of the present invention can achieve a high thickness without transverse wrinkling treatment, and has good air permeability, small suction resistance and high suction resistance stability.

[0086] In Comparative Example 1, no flash dried pulp is added, and the strength of the obtained cellulose paper is low, and it cannot be rolled into a groove filter rod. In Comparative Example 2, too much flash dried pulp is added, and the air permeability of the obtained cellulose paper is low, the suction resistance is large, and the thickness is low at the same quantitative. In Comparative Example 3, no mercerized pulp is added, and the air permeability of the obtained cellulose paper is low, and the thickness is low at the same quantitative, and the suction resistance is large. In Comparative Example 4, too much mercerized pulp is added, and the suction resistance is unstable. In Comparative Example 5, no in-pulp sizing is performed, and the strength of the obtained cellulose paper is low, and it cannot be rolled into a groove filter rod. Comparative Example 6 is a commonly used cellulose paper that has been corrugated laterally, and it has low air permeability, large suction resistance, and poor suction resistance stability.

[0087] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing high air permeability wrinkle-free cellulose paper, characterized in that: The steps include: S1. The pulp is dried by cylinder, flash dried pulp, mercerized pulp, chemical fiber and water to make pulp; S2. performing internal sizing on the slurry in step S1, and then obtaining base paper after forming, dehydrating and drying; S3. Surface sizing the base paper in step S2 and drying the base paper to obtain the cellulose paper; The mass ratio of the cylinder dried pulp, flash dried pulp, mercerized pulp and chemical fiber in step S1 is (0.2-1): (1-3.2): (1.2-5): (0-0.2).

2. The preparation method according to claim 1, characterized in that: The cylinder dried pulp in step S1 is at least one of hardwood pulp, softwood pulp, bagasse pulp, hemp pulp, straw pulp or bamboo pulp.

3. The preparation method according to claim 1, characterized in that: The average fiber length of the flash dried pulp in step S1 is 1.0-1.8 mm, the average fiber width is 20.0-27.0 um, the average fiber thickness is 0.10-0.18 mg / m, and the torsion index is 20.0-30.0%.

4. The preparation method according to claim 1, characterized in that: The average length of the mercerized pulp fibers in step S1 is 2.5-2.8 mm, the average width is 27.0-30.0 um, the average thickness is 0.12-0.18 mg / m, and the twist index is 20%-35%.

5. The preparation method according to claim 1, characterized in that: The average length of the chemical fiber in step S1 is 4-6 mm, and the linear density is 2.0-3.5 dtex.

6. The preparation method according to claim 1, characterized in that: The beating degree of the slurry in step S1 is 12-40° SR.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the internal sizing agent used for the internal sizing in step S2 to the slurry is (1-8): (92-99).

8. The preparation method according to claim 1, characterized in that: The mass ratio of the surface sizing agent used in the surface sizing in step S3 to the base paper is (0.2-4):

100.

9. A highly air-permeable wrinkle-free cellulose paper, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the cellulose paper according to claim 9 in preparing a grooved filter rod.

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