Preparation method of low-chromium content substrate of papermaking reconstituted tobacco, substrate and use thereof

Abstract

The present invention relates to the technical field of reconstituted tobacco production, and in particular to a method for preparing a low-chromium content substrate of reconstituted tobacco by a papermaking method, comprising the following steps: mixing and soaking reconstituted tobacco raw materials with a solvent to obtain a soaking liquid, and separating the soaking liquid to obtain a pulping material; mixing the pulping material with a diluent to obtain a diluted slurry; using a multi-stage pulping process to pulp the diluted slurry to obtain a tobacco slurry; mixing the tobacco slurry with an added fiber to obtain a reconstituted tobacco mixture; mixing the reconstituted tobacco mixture with a diluent, and papermaking to obtain a reconstituted tobacco substrate. The reconstitution process of the present invention improves the uniformity of the finished product, and in addition, by improving the existing pulping process and equipment in the papermaking industry, the control of the chromium content in the tobacco substrate is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of reconstituted tobacco production, and in particular to a preparation method of a low-chromium content substrate of papermaking reconstituted tobacco leaves, the substrate and use thereof. Background Art

[0002] Chromium in tobacco will be transferred to the smoke or the environment. Chromium is a harmful accumulative heavy metal element. When the human body ingests too much, it will cause harm to the nervous system, digestive system and hematopoietic system. Therefore, it is particularly important to control the content of heavy metals such as chromium in cigarettes and their additives. Papermaking reconstituted tobacco is a cigarette filler made from tobacco stems, tobacco dust and other materials as the main raw materials through pulping and papermaking. It is also called tobacco flakes or reconstituted tobacco. Because it can make full use of the remaining tobacco raw materials in cigarette processing and can also play a role in reducing tar and harm, it is increasingly valued by tobacco manufacturers.

[0003] In the production process of reconstituted tobacco leaves by papermaking, pulping is a key process in the production process. The control of pulping process conditions directly affects the subsequent production process, including important indicators such as production speed, water filtration, tensile strength, absorbency, coating rate, product yield, etc. The purpose of pulping is to use physical methods to treat the extracted solid materials so that they have the characteristics required by the papermaking machine, and the paper-made products can meet the quality requirements.

[0004] However, the current pulping process has the following shortcomings: the pulping process mainly uses the pulping process and equipment of the papermaking industry, and the process technology level and equipment level are relatively poor, resulting in a large amount of chromium content introduced from the pulping section, thereby causing the heavy metal content in the base sheet of the reconstituted tobacco to be too high. Therefore, a method for reducing the chromium content in the base sheet is developed, which can not only meet the pulping quality requirements, but also meet the process requirements for the chromium content limit in the base sheet, and ultimately obtain good economic and social benefits. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for preparing a low-chromium content substrate of reconstituted tobacco leaves by a papermaking process, a substrate and uses. The process method reduces the chromium content in the tobacco leaf substrate and improves the uniformity of the reconstituted tobacco leaf substrate.

[0006] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present invention provides a method for preparing a low-chromium content substrate of reconstituted tobacco leaves by a papermaking process, comprising the following steps: mixing reconstituted tobacco raw materials with a solvent and soaking them to obtain a soaking liquid, and separating the soaking liquid to obtain a pulping material; mixing the pulping material with a diluent to obtain a diluted slurry; using a multi-stage pulping process to pulp the diluted slurry to obtain a tobacco slurry; mixing the tobacco slurry with added fibers to obtain a reconstituted tobacco mixture; mixing the reconstituted tobacco mixture with a diluent, and papermaking to obtain a reconstituted tobacco leaf substrate.

[0007] The second aspect of the present invention provides the use of the method for preparing the aforementioned papermaking process reconstituted tobacco low-chromium content substrate in the field of reconstituted tobacco production.

[0008] The beneficial effects of the present invention are as follows: the papermaking recycling process of the present invention improves the uniformity of the finished product, and in addition, by improving the existing pulping process and equipment in the papermaking industry, the control of the chromium content in the tobacco substrate is achieved. DETAILED DESCRIPTION

[0009] The method for reducing the chromium content in a papermaking process reconstituted tobacco leaf substrate of the present invention comprises the following steps:

[0010] 1) mixing a reconstituted tobacco leaf raw material with a solvent and soaking the mixture to obtain a soaking liquid, and separating the soaking liquid to obtain a pulping material;

[0011] Specifically, the tobacco raw material of reconstituted tobacco is the tobacco raw material left over from cigarette processing, generally with tobacco stems and tobacco dust as the main raw materials, and the particle size is generally 30-80 mesh, and 30-40 mesh, 40-60 mesh, or 60-80 mesh can be selected. The tobacco raw material of reconstituted tobacco is the tobacco raw material left over from cigarette processing, and is generally above 30 mesh. After being collected after the cigarette processing process, a large amount of fine tobacco powder is mixed into the collected tobacco raw material. If too much fine tobacco powder and other raw materials enter the reconstituted tobacco manufacturing enterprise, on the one hand, it will affect the production and feeding process of reconstituted tobacco, and a large amount of dust will be generated during the feeding process. In the process of adding water after feeding, the fine tobacco powder combines with water to form an adhesive attached to the equipment body, causing cleaning problems. On the other hand, in the pulping and papermaking process, a large amount of water participates in the manufacturing process, so too much fine tobacco powder (above 80 mesh) will be taken away by water, thereby affecting the discharged water of the workshop, thereby increasing the pressure of water treatment.

[0012] The solvent can be water and / or alcohol, and the ethanol concentration in the alcohol is generally less than 90%. It has been found that water can be used. The mass ratio of the reconstituted tobacco raw material to the solvent is 1:(8-12), and can be 1:8, 1:9, 1:10, 1:11 or 1:12, which can be further adjusted according to actual needs. More specifically, the reconstituted tobacco leaf tobacco raw material is mixed with water and soaked for 25-35 minutes at 60-70°C. During the soaking process, it is necessary to stir continuously, and the stirring speed is 2-10 turns / min. After sufficient soaking, the pulping material insoluble in water is extracted, filtered, squeezed, and separated.

[0013] 2) mixing the pulping material with a diluent to obtain a diluted pulp;

[0014] Specifically, the diluent is water and / or alcohol, and the ethanol concentration in the alcohol is generally less than 90%. It has been found that water can be used. The mass ratio of the pulping material to the diluent is (2.5-5.5):100, preferably (3-4.5):100. The pulping material and the diluent are fully mixed to obtain a diluted slurry.

[0015] 3) using a multi-stage pulping process to pulp the diluted slurry to obtain tobacco slurry;

[0016] The beating process uses a double-disc refiner, preferably a DD series double-disc refiner, such as DD-500, DD-550 or DD-600, etc. The beating degree of the tobacco slurry obtained after the multi-stage pulping process is 30-75°SR, and the wet weight of the tobacco slurry is 0.1-4.0g, which can be selected from 0.1-0.5, 0.5-1, 1-2, 2-3, or 3-4. The raw materials needed for the preparation of reconstituted tobacco are tobacco stems, tobacco flakes, and tobacco dust. In order to ensure the uniformity of the finished paper after papermaking, the tobacco raw materials need to be pulped, and the very important indicators of the pulping process are the beating degree and wet weight. The multi-stage pulping process of reconstituted tobacco mainly includes two aspects. The first step is to achieve full disintegration of the tobacco raw materials so that there are no large tobacco stem skins and large pieces in the material to prevent them from being presented in the paper sheets. The second step is the pulping process, that is, by selecting a grinding disc with a splitting or cutting function, the wet weight of the pulp is reduced to a reasonable range, and the uniformity is further improved, thereby improving the uniformity of the paper sheets. At the same time, in order to prevent excessive beating, which causes the water and the pulp to be tightly combined, it is also necessary to ensure the dehydration efficiency of the pulp on the Internet. More specifically, pulping is a key process in the production process. The multi-stage pulping process refers to the use of a variety of different pulping process conditions for pulping. By strictly controlling the pulping process conditions and coordinating the pulping processes under different conditions, the product indicators can be improved. The pulping process of the present application adopts a 2-5-stage pulping process, which reduces the chromium content and improves the uniformity of the finished product while meeting other performance requirements.

[0017] More specifically, the diluted slurry is subjected to first-stage beating to obtain a primary slurry, the beating degree of the primary slurry is 30-55°SR, and the wet weight of the primary slurry is 2.0-4.0 g, which can be 2-3 or 3-4. Then, the primary slurry is subjected to second-stage beating to obtain a tobacco slurry, the beating degree of the tobacco slurry is 55-75°SR, and the wet weight of the tobacco slurry is 0.1-2.0 g, which can be 0.1-0.5, 0.5-1, or 1-2.

[0018] More specifically, a DD-500 low-concentration double-disc mill was used for the first-stage beating. The first beating conditions were: an inlet flow rate of 10 to 30 m 3 / h, optional 10~20m 3 / h or 20~30m 3 / h; the mill pulp pressure is 150-220KPa, and the beating power is 90-120Kw. It can be circulated multiple times under the first-stage beating conditions until the beating degree and wet weight requirements of the first-stage pulp are met. The beating degree of the first-stage pulp suitable for this application is 30-55°SR, and 30-35°SR, 35-40°SR, 40-45°SR, 45-50°SR or 50-55°SR can be selected; the wet weight of the first-stage pulp is 2.0-4.0g, and 2.0-2.5g, 2.5-3.0g, 3.0-3.5g or 3.5-4.0g can be selected. The DD-500 low-concentration double-disc mill is used for the second-stage beating. The second-stage beating conditions are: the inlet flow rate is 20-30m 3 / h, optional 20~25m 3 / h or 25~30m 3 / h; mill pulp pressure is 150-220KPa, beating power is 90-120Kw, can be cycled multiple times under the second stage beating conditions until the beating degree and wet weight requirements of tobacco slurry are met, the beating degree of tobacco slurry suitable for this application is 55-75°SR, 55-60°SR, 60-65°SR, 65-70°SR or 70-75°SR can be selected. The wet weight of tobacco slurry is 0.1-2.0g, 0.1-0.5g, 0.5-1.0g, 1.0-1.5g or 1.5-2.0g can be selected.

[0019] The chromium content in the grinding gear material of the double disc refiner is 1-18%, preferably, the chromium content in the grinding gear material of the first stage double disc refiner is 3-18%, preferably 3-7%; the chromium content in the grinding gear material of the second stage double disc refiner is 1-18%, preferably 3-7%. The inventor unexpectedly discovered that the chromium in the grinding gear material of the refiner will introduce chromium into the process during operation, so the chromium content in the grinding gear is regulated under the premise of meeting the use requirements, which greatly reduces the chromium content in the substrate.

[0020] 4) mixing the tobacco slurry with added fibers to obtain a reconstituted tobacco mixture;

[0021] The mass ratio of tobacco pulp to additional fiber is (10-20):1, and can be (10-15):1 or (15-20):1. The additional fiber is selected from bleached conifer pulp, unbleached flax pulp and / or bleached broadleaf pulp, and the amount and type of the additional fiber are selected according to the bursting strength, equilibrium moisture content, filling value or bulk of the reconstituted tobacco leaf base sheet.

[0022] 5) Mixing the reconstituted tobacco mixture with a diluent, and making a reconstituted tobacco base sheet.

[0023] The diluent is water. The mass ratio of the reconstituted tobacco mixture to the diluent is (0.8-1):100, which meets the papermaking requirements.

[0024] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] It should be noted that the process equipment or devices not specifically specified in the following examples are conventional equipment or devices in the art, or simple modifications of conventional equipment or devices, such as custom-made grinding teeth with different chromium contents. All pressure values ​​and ranges refer to absolute pressures.

[0026] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; and, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0027] Example 1

[0028] 1) Select 40 mesh tobacco stems, tobacco flakes and tobacco dust to prepare tobacco flake raw materials, mix them, add water to soak, stir and extract, the weight of reconstituted tobacco raw materials: the weight of water = 1:8, the temperature is 65° C., the extraction time is 25 minutes, the materials are filtered, squeezed and separated, and the obtained insoluble components are used as pulping materials.

[0029] 2-3) The pulping material is diluted with water to a concentration of 3.0 wt% (i.e., the mass ratio of the pulping material to water is 3:100), and the first-stage beating is performed. The process parameters of the first-stage beating are: the beating equipment adopts a DD500 low-concentration double-disc refiner, the chromium content of the grinding teeth material is 3%, and the pulp inlet flow rate is 10m 3 / h, mill pulp pressure is 150KPa, beating power is 90Kw, the beating degree of the obtained pulp is 30°SR, and the wet weight of the pulp is 3.3g. The first-stage pulp obtained is subjected to second-stage beating. The process parameters of the second-stage beating are: the beating equipment adopts DD500 low-concentration double-disc pulping machine, the chromium content of the grinding tooth material is 1%, the pulp inlet flow rate is 10m 3 / h, the mill pulp pressure is 150KPa, the beating power is 90Kw, the beating degree of the obtained slurry is 55°SR, and the wet weight of the slurry is 2.0g.

[0030] 4-5) The tobacco material after pulping is mixed with the external fiber in a mixing ratio of 20:1, and the obtained mixture is diluted to a concentration of 0.8wt%, and then put on the net for papermaking to finally obtain a tobacco sheet substrate, the chromium content in the substrate is 3.982mg / kg, the uniformity coefficient of the substrate is 52, the service life of the first-stage pulping grinding disc is 1 set / 200 tons, and the service life of the second-stage pulping grinding disc is 1 set / 100 tons.

[0031] Example 2

[0032] 1) Select 50 mesh tobacco stems, tobacco flakes and tobacco dust to prepare tobacco flake raw materials, mix them, add water to soak, stir and extract, the weight of reconstituted tobacco raw materials: the weight of water = 1:10, the temperature is 60° C., the extraction time is 30 minutes, the materials are filtered, squeezed and separated, and the obtained insoluble components are used as pulping materials.

[0033] 2-3) The pulping material is diluted with water to a concentration of 3.5wt% (i.e., the mass ratio of the pulping material to water is 3.5:100), and the first-stage beating is performed. The process parameters of the first-stage beating are: the beating equipment adopts a DD500 low-concentration double-disc refiner, the chromium content of the grinding teeth material is 7%, and the pulp inlet flow rate is 20m 3 / h, mill pulp pressure is 200KPa, beating power is 110Kw, the beating degree of the obtained pulp is 45°SR, and the wet weight of the pulp is 2.7g. The first-stage pulp obtained is subjected to second-stage beating. The process parameters of the second-stage beating are: the beating equipment adopts DD500 low-concentration double-disc pulping machine, the chromium content of the grinding tooth material is 7%, the pulp inlet flow rate is 20m 3 / h, the mill pulp pressure is 180KPa, the beating power is 100Kw, the beating degree of the obtained slurry is 60°SR, and the wet weight of the slurry is 1.4g.

[0034] 4-5) The tobacco material after pulping is mixed with the external fiber in a mixing ratio of 15:1, and the obtained mixture is diluted to a concentration of 0.9wt%, and then put on the net for papermaking to finally obtain a tobacco sheet substrate, the chromium content in the substrate is 7.093mg / kg, the substrate uniformity coefficient is 65, the service life of the first-stage pulping grinding disc is 1 set / 1000 tons of products, and the service life of the second-stage pulping grinding disc is 1 set / 1000 tons of products.

[0035] Example 3

[0036] 1) Select 50 mesh tobacco stems, tobacco flakes and tobacco dust to prepare tobacco flake raw materials, mix them, add water to soak, stir and extract, the weight of reconstituted tobacco raw materials: the weight of water = 1:12, the temperature is 70° C., the extraction time is 35 minutes, the materials are filtered, squeezed and separated, and the obtained insoluble components are used as pulping materials.

[0037] 2)-3) The pulping material is diluted with water to a concentration of 3.5wt% (i.e., the mass ratio of the pulping material to water is 3.5:100), and the first stage of pulping is performed. The process parameters of the first stage of pulping are: the pulping equipment adopts a DD500 low-concentration double-disc pulping machine, the chromium content of the grinding teeth material is 18%, and the pulp inlet flow rate is 20m 3 / h, mill pulp pressure is 200KPa, beating power is 120Kw, the beating degree of the obtained pulp is 55°SR, and the wet weight of the pulp is 2.1g. The first-stage pulp obtained is subjected to second-stage beating. The process parameters of the second-stage beating are: the beating equipment adopts DD500 low-concentration double-disc pulping machine, the chromium content of the grinding tooth material is 16%, and the pulp inlet flow rate is 20m 3 / h, the mill pulp pressure is 180KPa, the beating power is 110Kw, the beating degree of the obtained slurry is 75°SR, and the wet weight of the slurry is 0.2g.

[0038] 4)-5) The tobacco material after pulping is mixed with the external fiber in a mixing ratio of 10:1, and the obtained mixture is diluted to a concentration of 1.0%, and then put on the net to make a tobacco sheet substrate, and the chromium content in the substrate is 20.567 mg / kg, the substrate uniformity coefficient is 72, the service life of the first-stage pulping grinding disc is 1 set / 1200 tons of products, and the service life of the second-stage pulping grinding disc is 1 set / 1200 tons of products.

[0039] Comparative Example 1

[0040] Using the original paper industry process:

[0041] 1) Select 40 mesh tobacco stems, tobacco flakes and tobacco dust to prepare tobacco flake raw materials, mix them, add water to soak, stir and extract, the weight of reconstituted tobacco raw materials: the weight of water = 1:8, the temperature is 65° C., the extraction time is 25 minutes, the materials are filtered, squeezed and separated, and the obtained insoluble components are used as pulping materials.

[0042] 2) The pulping material is diluted with water to a concentration of 20 wt% (i.e., the mass ratio of the pulping material to water is 20:100), and the first-stage beating is performed. The process parameters of the first-stage beating are: the beating equipment adopts a high-concentration pulping machine, the chromium content of the grinding tooth material is 18%, and the pulp inlet flow rate is 30m 3 / h, mill pulp pressure is 300KPa, beating power is 170Kw, the beating degree of the obtained pulp is 30°SR, and the wet weight of the pulp is 3.3g. The first-stage pulp obtained is subjected to second-stage beating. The process parameters of the second-stage beating are: the beating equipment adopts DD500 low-concentration pulping machine, the chromium content of the grinding tooth material is 18%, and the pulp inlet flow rate is 40m 3 / h, the mill pulp pressure is 300KPa, the beating power is 100Kw, the beating degree of the obtained slurry is 37°SR, and the wet weight of the slurry is 1.8g.

[0043] 3) The tobacco material after pulping is mixed with the external fiber in a mixing ratio of 20:1, and the obtained mixture is diluted to a concentration of 0.8wt%, and then put on the net for papermaking to finally obtain a tobacco sheet substrate, the chromium content in the substrate is 30.582mg / kg, the uniformity coefficient of the substrate is 25, the service life of the first-stage pulping grinding disc is 1 set / 500 tons, and the service life of the second-stage pulping grinding disc is 1 set / 1000 tons.

[0044] In summary, the preparation method of the present application improves the uniformity coefficient of the tobacco substrate and reduces the chromium content in the substrate.

[0045] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and evolutions of the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a low-chromium content substrate of papermaking reconstituted tobacco, comprising the following steps: 1) Select 50 mesh tobacco stems, tobacco flakes and tobacco dust to prepare reconstituted tobacco raw materials, mix them, add water to soak, stir and extract, the weight of reconstituted tobacco raw materials: the weight of water = 1:12, the temperature is 70°C, the extraction time is 35 minutes, the materials are filtered, squeezed and separated, and the insoluble components obtained are used as pulping materials; 2)-3) The pulping material is diluted and added with water, and the dilution concentration is 3.5wt%, and the first stage beating is carried out. The process parameters of the first stage beating are: the beating equipment adopts DD500 low-concentration double-disc refiner, the chromium content in the material of the grinding teeth is 18%, the pulp inlet flow rate is 20 m³ / h, the mill pulp pressure is 200KPa, the beating power is 120Kw, the beating degree of the obtained pulp is 55°SR, and the wet weight of the pulp is 2.1g; the first-stage pulp obtained is subjected to the second stage beating, and the process parameters of the second stage beating are: the beating equipment adopts DD500 low-concentration double-disc refiner, the chromium content in the material of the grinding teeth is 16%, the pulp inlet flow rate is 20 m³ / h, the mill pulp pressure is 180KPa, the beating power is 110Kw, the beating degree of the obtained pulp is 75°SR, and the wet weight of the pulp is 0.2g; 4)-5) The pulped tobacco material is mixed with the external fiber in a mixing ratio of 10:1, and the obtained mixture is diluted to a concentration of 1.0%, and then the mixture is put on the net for papermaking to finally obtain a tobacco sheet substrate, the chromium content in the substrate is 20.567 mg / kg, and the substrate uniformity coefficient is 72.