A method for preparing thick slurry for preparing reconstituted tobacco leaf coating liquid for papermaking

Abstract

The present application is a kind of preparation method of thick slurry for papermaking process reconstituted tobacco coating liquid, the preparation method comprises the following steps: 1, the material is divided into different material modules, and pre-fabricated;2, according to the material characteristics, different material modules are added step by step and gradient temperature, finally obtain the thick slurry.The above-mentioned thick slurry is treated under negative pressure, then is proportionally prepared into coating liquid with stem leaf paste and spice, and is used for coating papermaking process reconstituted tobacco.The present application solves the problems that ultrafine powder is easy to appear caking, uneven dispersion and cause the quality fluctuation of reconstituted tobacco after coating in the process of preparing thick slurry, and provides support for the large-scale application of thick slurry prepared based on ultrafine powder in papermaking process reconstituted tobacco production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of processing and manufacturing of papermaking process reconstituted tobacco, and particularly relates to a method for preparing a thick slurry of coating liquid for papermaking process reconstituted tobacco. BACKGROUND

[0002] Reconstituted tobacco, also known as recombined tobacco, has the characteristics of strong plasticity, high homogenization and high controllability while maintaining the effective components of natural tobacco, and thus has become an indispensable raw material unit for traditional cigarettes.

[0003] During the extraction and concentration of tobacco raw materials and functional plant materials, some volatile substances are lost or some substances change in chemical properties. Therefore, high-quality tobacco raw materials or functional components of tobacco and exogenous plant materials that have been lost are ultra-finely pulverized to prepare a thick slurry, which is then added to the coating liquid of papermaking process reconstituted tobacco for loading to improve the "perfume loading" and "taste loading" functions of the reconstituted tobacco. For example, CN112853811A discloses "a reconstituted tobacco containing ultra-fine plum powder and a preparation method thereof", which directly or previously disperses the plum powder in a solvent to prepare a thick slurry at a proportion of 0.2% to 50% of the absolute dry mass of the reconstituted tobacco product, and then adds the thick slurry to a concentrated liquid to prepare a coating liquid. Finally, the coating liquid is coated on the base of the reconstituted tobacco sheet, and the reconstituted tobacco is prepared through processes such as drying and cutting. CN112971194A discloses "a process for loading tobacco flavor", which processes refined solid flavors through a colloidal mill to obtain a thick slurry or paste with high homogeneity, and then coats the thick slurry or paste on a sheet base by roller coating to prepare reconstituted tobacco.

[0004] The above patents solve the problems of loss of some volatile substances or changes in chemical properties of some substances during the extraction and concentration of tobacco raw materials and functional plant materials by preparing ultra-fine powders into a thick slurry and then preparing a coating liquid with stem leaf paste and flavors, thereby improving the perfume loading and taste loading functions of papermaking process reconstituted tobacco. However, the ultra-fine powders are prone to caking and uneven dispersion during the preparation of the thick slurry. SUMMARY

[0005] To solve the above technical problems, the present application provides a method for preparing a thick slurry of coating liquid for papermaking process reconstituted tobacco, which comprises the following steps:

[0006] Step 1: divide the materials into the following four material modules and prepare them:

[0007] Ultra-fine powder module preparation: prepare functional plant materials or tobacco raw materials with a mesh size of 300-1000 mesh and a moisture content of 8%±1%, and a particle size distribution of ≥D80; the temperature during the preparation process is ≤45℃;

[0008] Prefabrication of the additive module: The additives include chitosan, guar gum, and carboxymethyl cellulose, wherein the chitosan is added in an amount of 0.1%-0.5%, the guar gum is added in an amount of 0.1%-0.5%, and the sodium carboxymethyl cellulose is added in an amount of 0.1%-0.5%, wherein the percentages are based on the absolute dry weight of the ultrafine powder module. The additives are mixed in proportion to form an additive module, which is then mixed with 20-40 times its weight of water at 65-70° C. for 15-20 minutes at a stirring speed of 300-350 rpm;

[0009] Prefabrication of moisture-proof material module: The moisture-proof material comprises tamarind polysaccharide and beeswax, wherein the tamarind polysaccharide is added in a proportion of 0.1%-0.5%, and the beeswax is added in a proportion of 0.1%-0.5%, and the percentages are based on the absolute dry weight of the ultrafine powder module. The above moisture-proof materials are mixed in proportion to form a moisture-proof material module, and then mixed with 10-30 times the absolute dry weight of water at 70-75° C. for 20-30 minutes, and the stirring speed is 500-550 rpm;

[0010] Prefabrication of the moisturizing material module: The moisturizing material comprises glycerin and propylene glycol, with glycerin added at a ratio of 0.5%-30% and propylene glycol added at a ratio of 0.3%-20%. The percentages are based on the absolute dry weight of the ultrafine powder module. The moisturizing materials are mixed in proportion to form the moisturizing material module, which is then mixed with 5-10 times its absolute dry weight of water at ambient temperature for 5-10 minutes, stirring at 60-70 rpm.

[0011] Step 2: Each material module is added step by step and the temperature is increased gradually as follows:

[0012] (1) Mix and stir the prepared moisturizing material module and the auxiliary agent module in a prefabricated tank at room temperature at a stirring speed of 60-80 rpm for 5-10 min;

[0013] (2) Add a certain amount of production water to the slurry mixing tank and heat it. When the water temperature in the slurry mixing tank rises to 40-45°C, add the moisturizing material module and the auxiliary agent module mixed in the prefabricated tank to the slurry mixing tank and stir at a stirring speed of 50-70 rpm for 5-10 min.

[0014] (3) Continue to heat the material in the slurry mixing tank. When the temperature reaches 55-60°C, add the moisture-proof material module, stir at a speed of 160-200 rpm, and stir for 10-15 minutes;

[0015] (4) Continuously heat the material in the slurry mixing tank until the temperature reaches 68±2°C and stir at a constant temperature at a speed of 160-200 rpm for 10-15 min;

[0016] (5) Using a linear powder-liquid dispersing mixer, the liquid and ultrafine powder are mixed online at a rotation speed of 1500-2000 rpm; then the dynamically blended thick slurry is transported to a buffer tank using a colloid mill for thick slurry balance homogenization, the temperature in the buffer tank is 50-55°C, the stirring speed is 160-200 rpm, the equilibrium homogenization time is 15-30min, the equilibrium concentration is 10%-30%, and the concentration deviation is ±1.0% to obtain the thick slurry.

[0017] In practice, the balanced thick slurry is subjected to negative pressure treatment (negative pressure 0.1-0.3Mpa), and then mixed with stem leaf paste and spices in proportion to form a coating liquid (the added amount accounts for 3%-50% of the mass of the raw materials), and then the reconstituted tobacco leaves are coated and dried. During coating, the amount of coating liquid in the coating tank is strictly controlled, that is, the amount of coating liquid in the coating tank is 5%-7% more than the coating amount (absolutely dry).

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The characteristic of the present invention is that the constituent materials of the thick slurry are grouped into specific modules, and then prefabricated separately under different temperatures and stirring conditions according to the material characteristics of each module, and mixed into a thick slurry according to a specific adding sequence (the stability effect is not as good as the present invention if it is not in this sequence). Compared with other mixing methods and adding sequences in the prior art, the present invention solves the problems of agglomeration and uneven dispersion of ultrafine powders during the preparation of thick slurry, and creates favorable conditions for giving full play to the aroma and flavor carrying functions of reconstituted tobacco leaves by the papermaking method. The thick slurry can improve the quality stability of the reconstituted tobacco leaves after being coated with a coating liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] none. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments.

[0022] The present invention is an improvement on existing technologies. The process equipment used in the present invention is commercially available tobacco equipment, specifically including a pulverizer, a prefabricated tank, a slurry mixing tank, and an inline powder-liquid dispersing mixer. To demonstrate the superior effects of the present invention, comparative tests are conducted below.

[0023] Comparative Example 1

[0024] The thick slurry is prepared by the traditional all-in-one mixing method, and the coating liquid is prepared and then coated on the papermaking method reconstituted tobacco leaves, wherein the ultrafine powder is made of plum raw material.

[0025] Prepare 240 kg of plum raw material (including 150 kg of black plums, 60 kg of green plums, and 30 kg of western plums), and finely grind the plums, control the temperature at ≤45°C, grind the mesh size to 800 mesh, and have a particle size distribution of D85 to obtain ultrafine powder; then take 200 kg from the prefabricated ultrafine powder, and then mix it with auxiliary agents, moisture-proof materials, moisturizing materials and water according to the percentage of the absolute dry weight of the ultrafine powder. The amount of water is such that the total concentration of the remaining non-aqueous materials in the final thick paste is 20%. The specific materials are as follows: the auxiliary material module is added at 0.3%, including 0.2% chitosan and 0.1% guar gum; the moisture-proof material module is added at 0.3%, including 0.2% tamarind polysaccharide and 0.1% beeswax; and the addition is made at 0.3%, including 0.2% glycerol and 0.1% propylene glycol. The thick slurry obtained after mixing the above materials is then mixed with stem leaf paste and spice cases to prepare a coating liquid, which is used to coat papermaking reconstituted tobacco leaves. During the production process, the coating liquid and the finished reconstituted tobacco leaves are sampled, and a sample of the coating liquid and the finished product is taken every 3 minutes, with a total of 20 samples, and then the concentration and main physical indicators are tested.

[0026] Example 1

[0027] After the thick slurry is prepared and the coating liquid is prepared according to the method of the present invention, the coating is applied to the papermaking process reconstituted tobacco leaves.

[0028] Similarly, prepare 240 kg of plum raw material (including 150 kg of black plums, 60 kg of green plums, and 30 kg of western prunes), as well as various additives, moisture-proof materials, moisture-retaining materials, and water. However, according to the method of the present invention, the mixture is prefabricated in four modules, then gradually heated and added stepwise to form a thick slurry. The specific method includes the following steps:

[0029] Step 1: Divide the materials into the following four material modules and prefabricate them:

[0030] (1) Preparation of ultrafine powder module: First, the moisture balance of the ultrafinely pulverized plum module (black plum, green plum, and western plum = 5:2:1) was carried out, and the moisture content was controlled at 10% ± 1%; the pulverization temperature was controlled at ≤45°C, the pulverization mesh size was 800 mesh, the moisture content was 7% ± 1%, and the particle size distribution was D85. The mixture was mixed according to the above ratio to prefabricate a 240 kg ultrafine powder module.

[0031] (2) Preparation of the auxiliary agent module: chitosan 0.2% and guar gum 0.1% are added to the ultrafine powder module at 0.3% of its absolute dry weight, and the above auxiliary agents are mixed in proportion to form an adhesive module, which is then prefabricated with 68°C production water at a ratio of 1:30 of their absolute dry weight. The prefabrication temperature is 68±2°C, the time is 15 minutes, and the stirring speed is 300 rpm.

[0032] (3) Prefabrication of moisture-proof material module: 0.3% of the absolute dry weight of the ultrafine powder module is added, including 0.2% tamarind polysaccharide and 0.1% beeswax. The above moisture-proof material modules are mixed in proportion to form a moisture-proof material module, and then prefabricated with 70°C production water at a ratio of 1:10 of their absolute dry weight. The prefabrication temperature is 70±2°C, the time is 20 minutes, and the stirring speed is 500 rpm.

[0033] (4) Prefabrication of moisturizing material module: Add 0.3% of the absolute dry weight of the ultrafine powder module, of which glycerol is added in a proportion of 0.2% and propylene glycol is added in a proportion of 0.1%. The above moisturizing material modules are mixed in proportion to form a moisturizing material module, and then prefabricated with production water (normal temperature) at a ratio of 1:5 of its absolute dry weight. The prefabrication temperature is normal temperature, the time is 5 minutes, and the stirring speed is 60 rpm.

[0034] Step 2: Each material module is added step by step and the temperature is increased gradually as follows

[0035] (1) At room temperature, the prepared moisturizing material module and the auxiliary agent module are first mixed and stirred in a prefabricated tank at a speed of 60 rpm for 10 min.

[0036] (2) Add 900 kg of production water to the slurry mixing tank and heat it. When the water temperature in the slurry mixing tank rises to 42±2℃, add the moisturizing material module and the auxiliary agent module mixed in the prefabricated tank to the slurry mixing tank and stir at a speed of 60 rpm and a stirring time of 10 min.

[0037] (3) Continue to heat the material in the slurry mixing tank. When the temperature reaches 57±2℃, add the moisture-proof material module, stir at a speed of 180 rpm, and stir for 10 minutes.

[0038] (4) The material in the slurry mixing tank is continuously heated to 68±2°C and stirred at a constant temperature at a speed of 160-200 rpm for 10-15 min.

[0039] (5) Use a linear powder-liquid dispersing mixer to achieve online mixing of liquid and ultrafine powder, with a rotation speed of 1800 rpm and a liquid discharge deviation of ±0.01m 3 , the powder discharge deviation is ±0.01kg / min; then the dynamically blended thick slurry is transported to the buffer tank by using a colloid mill, and according to the thick slurry concentration designed to be 15%, hot water with a temperature of 68±2℃ is used for water replenishment; finally, the thick slurry is homogenized, wherein the thick slurry temperature during the homogenization process is 68±2℃, the stirring speed is 180 rpm, the equilibrium homogenization time is 20min, and the concentration is 15%±1.0%, thereby obtaining the thick slurry.

[0040] Step 3: After the above thick slurry is balanced, it is subjected to negative pressure and degassing treatment (negative pressure is 0.1Mpa), and the temperature is reduced to 55±2°C. It is then mixed with stem leaf paste and spices in proportion to form a coating liquid for coating and drying the reconstituted tobacco leaves (the addition ratio is 7%). During coating, the amount of coating liquid in the coating tank is strictly controlled, that is, the amount of coating liquid in the coating tank is 5% more than the coating amount (absolute dry).

[0041] Step 4: Comparison of finished product samples

[0042] Finished product samples were taken every three minutes, for a total of 20 samples. The samples were then tested for slurry consistency and the finished product basis weight, thickness, fill value, and longitudinal tensile strength. Basis weight was measured according to GB / T 451.2-2002, thickness according to GB / T 451.3-2002, fill value according to YC / T 152-2001, and longitudinal tensile strength according to GB / T 12914-2008. The results are as follows.

[0043] Table 1-1 Thick pulp concentration test results (%)

[0044] Sample name average value(%) Standard deviation Range (%) Coefficient of variation (%) Comparative Example 1 14.15 1.28 3.21 9.05 Example 1 14.91 0.68 1.52 4.56

[0045] It can be seen from Table 1-1 that after adopting the present invention, the coefficient of variation of the thick slurry concentration prepared by the material in Example 1 is reduced, the range is smaller, the concentration deviation is within ±1.0%, and the stability of the thick slurry quality is significantly improved.

[0046] Table 1-2 Test results of main physical indicators of reconstituted tobacco leaves prepared from materials of comparative example 1

[0047]

[0048] Table 1-3 Test results of main physical indicators of reconstituted tobacco leaves prepared from materials of Example 1

[0049]

[0050] It can be seen from Tables 1-2 and 1-3 that after adopting the present invention, the coefficient of variation and range of the main physical indicators of the reconstituted tobacco leaves are reduced, and the stability is significantly improved.

[0051] Comparative Example 2

[0052] A thick slurry was prepared by the traditional all-in-one mixing method, and the coating liquid was prepared with the thick slurry and then coated on papermaking reconstituted tobacco leaves. The ultrafine powder was made from 320 kg of red large tobacco raw material (grades C3F and B2F, with a grade ratio of 6:4).

[0053] Red tobacco leaves are finely ground at a temperature of ≤45°C to a 600 mesh size and a D90 particle size distribution to produce an ultrafine powder. 300 kg of this pre-made ultrafine powder is then added and mixed with additives, moisture-proofing materials, moisturizing materials, and water in proportion to the absolute dry weight of the ultrafine powder. The amount of water ensures a total concentration of 20% of the remaining non-aqueous materials in the final thick paste. The ingredients are as follows: 0.3% of the additives module, including 0.2% chitosan and 0.1% guar gum; 0.3% of the moisture-proofing module, including 0.2% tamarind polysaccharide and 0.1% beeswax; and 0.3% of the moisturizing materials module, including 0.2% glycerin and 0.1% propylene glycol. The thick slurry obtained after mixing the above materials is then mixed with stem leaf paste and spice cases to prepare a coating liquid, which is used to coat papermaking reconstituted tobacco leaves. During the production process, the coating liquid and the finished reconstituted tobacco leaves are sampled, and a sample of the coating liquid and the finished product is taken every 3 minutes, with a total of 20 samples, and then the concentration and main physical indicators are tested.

[0054] Example 2

[0055] According to the method of the present invention, a thick slurry is prepared, and a coating liquid is prepared with the thick slurry to coat the papermaking process reconstituted tobacco leaves.

[0056] Similarly, 320 kg of red large tobacco raw material (grades C3F and B2F, with a grade ratio of 6:4), as well as various additives, moisture-proof materials, moisture-retaining materials, and water are prepared. However, according to the method of the present invention, the raw material is first prefabricated in four modules, and then gradually heated and added in steps to form a thick slurry. The specific method includes the following steps:

[0057] Step 1: Divide the materials into the following four material modules and prefabricate them:

[0058] (1) Preparation of ultrafine powder modules: First, the moisture balance of the ultrafinely crushed red tobacco leaf module is carried out, and the moisture content is controlled at 11% ± 1%; the crushing temperature is controlled at ≤ 45 ° C, the crushing mesh size is 600 mesh, the moisture content is 7% ± 1%, and the particle size distribution is D90. According to the above proportions, the mixture is mixed and prefabricated into a 240 kg ultrafine powder module.

[0059] (2) Prefabrication of auxiliary material module: chitosan 0.2% and guar gum 0.1% are added according to 0.3% of the absolute dry weight of the ultrafine powder module. The above auxiliary materials are mixed in proportion to form an adhesive module, and then prefabricated with 68°C production water at a ratio of 1:30 of their absolute dry weight. The prefabrication temperature is 68±2°C, the time is 15 minutes, and the stirring speed is 300 rpm.

[0060] (3) Prefabrication of moisture-proof material module: 0.3% of the absolute dry weight of the ultrafine powder module is added, including 0.2% tamarind polysaccharide and 0.1% beeswax. The above moisture-proof material modules are mixed in proportion to form a moisture-proof material module, and then prefabricated with 70°C production water at a ratio of 1:10 of their absolute dry weight. The prefabrication temperature is 70±2°C, the time is 20 minutes, and the stirring speed is 500 rpm.

[0061] (4) Prefabrication of moisturizing material module: Add 0.3% of the absolute dry weight of the ultrafine powder module, of which glycerol is added in a proportion of 0.2% and propylene glycol is added in a proportion of 0.1%. The above moisturizing material modules are mixed in proportion and modulated into moisturizing material modules, which are prefabricated with production water (normal temperature) at a ratio of 1:5 of their absolute dry weight. The prefabrication temperature is normal temperature, the time is 5 minutes, and the stirring speed is 60 rpm.

[0062] Step 2: Each material module is added step by step and the temperature is increased gradually as follows

[0063] (1) At room temperature, the prepared moisturizing material module and the auxiliary agent module are first mixed and stirred in a prefabricated tank at a speed of 60 rpm for 10 min.

[0064] (2) Add 900 kg of production water to the slurry mixing tank and heat it. When the water temperature in the slurry mixing tank rises to 42±2℃, add the moisturizing material module and the auxiliary agent module mixed in the prefabricated tank to the slurry mixing tank and stir at a speed of 60 rpm and a stirring time of 10 min.

[0065] (3) Continue to heat the material in the slurry mixing tank. When the temperature reaches 57±2℃, add the moisture-proof material module, stir at a speed of 180 rpm, and stir for 10 minutes.

[0066] (4) The material in the slurry mixing tank is continuously heated to 68±2°C and stirred at a constant temperature at a speed of 160-200 rpm for 10-15 min.

[0067] (5) Use a linear powder-liquid dispersing mixer to achieve online mixing of liquid and ultrafine powder, with a rotation speed of 1600 rpm and a liquid discharge deviation of ±0.01m 3 , the powder discharge deviation is ±0.01kg / min; then the dynamically blended slurry is transported to the buffer tank using a colloid mill, and designed according to a 20% slurry concentration, and water is added using hot water at a temperature of 55±2°C; finally, the slurry is homogenized, wherein the slurry temperature during the homogenization process is 55±2°C, the stirring speed is 180 rpm, the equilibrium homogenization time is 20min, and the concentration is 20%±1.0%.

[0068] Step 3, after the above thick stock is balanced, negative pressure and degassing treatment are performed (wherein the negative pressure is 0.1 Mpa), and then the thick stock is mixed with stem and leaf paste and spices according to a proportion to prepare coating liquid (the addition amount is 15% of the mass of the raw material), and then reconstituted tobacco coating and drying are performed, wherein the amount of the coating liquid in the coating tank is strictly controlled during coating, i.e. the amount of the coating liquid in the coating tank is 5% (dry) more than the coating amount.

[0069] Step 4, comparison of finished product samples

[0070] Finished product sampling is performed every 3 minutes, a total of 20 samples are taken, and then the thick stock concentration and the finished product quantitative, thickness, filling value, and longitudinal tensile strength are detected, wherein the quantitative is detected according to GB / T 451.2-2002, the thickness is measured according to GB / T 451.3-2002, the filling value is detected according to YC / T 152-2001, and the longitudinal tensile strength is detected according to GB / T 12914-2008. The specific results are as follows.

[0071] Table 2-1 thick stock concentration detection results (%)

[0072] Sample name average value(%) Standard deviation Range (%) Coefficient of variation (%) Comparative Example 2 19.11 1.56 3.42 8.16 Example 2 19.92 0.82 1.76 4.12

[0073] As shown in Table 2-1, after the present application is adopted, the variation coefficient of the thick stock concentration of the material conditioning of Example 2 is reduced, the range is smaller, the concentration deviation is within ±1.0%, and the stability of the thick stock quality is significantly improved.

[0074] Table 2-2 main physical index detection results of the reconstituted tobacco prepared by the material of Comparative Example 2

[0075]

[0076] Table 2-3 main physical index detection results of the reconstituted tobacco prepared by the material of Example 2

[0077]

[0078] As shown in Tables 2-2 and 2-3, after the present application is adopted, the variation coefficient and the range of the main physical indexes of the reconstituted tobacco are reduced, and the stability is significantly improved.

[0079] Comparative Example 3

[0080] The thick stock is prepared by the traditional one-mixing method, and the coating liquid is prepared by using the thick stock to coat the papermaking reconstituted tobacco. The superfine powder adopts 320 kg of tobacco leaf raw material (grades C3F and B2F, grade ratio 4:6), and the difference from Comparative Example 2 is that 20% of the tobacco leaf raw material is added to the thick stock as a non-tobacco source smoke agent material for heating special reconstituted tobacco for cigarettes.

[0081] The red tobacco leaf module is finely ground at a temperature of ≤45°C to a 270 mesh size and a D90 particle size distribution to produce an ultrafine powder. 300 kg of this pre-made ultrafine powder is then added and mixed with additives, smoke-generating agents, moisture-proof materials, moisturizing materials, and water in proportion to the absolute dry weight of the ultrafine powder. The amount of water ensures a total concentration of the remaining non-aqueous materials in the final thick slurry of 25%. The specific materials are as follows: the additive module is added at 0.5%, including 0.3% chitosan and 0.2% guar gum; the moisture-proof material module is added at 0.5%, including 0.3% tamarind polysaccharide and 0.2% beeswax; and the moisturizing material module is added at 20%, including 16% glycerin and 4% propylene glycol. The thick slurry obtained after mixing the above materials is then mixed with stem leaf paste and spice cases to prepare a coating liquid, which is used to coat papermaking reconstituted tobacco leaves. During the production process, the coating liquid and finished reconstituted tobacco leaves are sampled, and a sample of the coating liquid and the finished product is taken every 3 minutes, with a total of 20 samples. The thick slurry concentration and main physical indicators are then tested.

[0082] Example 3

[0083] According to the method of the present invention, a thick slurry is prepared, and a coating liquid is prepared with the thick slurry to coat the papermaking process reconstituted tobacco leaves.

[0084] Similarly, 320 kg of tobacco strips (grades C3F and B2F, with a grade ratio of 4:6) were prepared. A 20% by weight moistening material module (also serving as a non-tobacco smoke generator) was added to the strips. Various additives, moisture-proof materials, moistening materials, and water were also prepared. However, according to the present invention, the prefabrication process was divided into four modules, followed by gradual temperature increase and stepwise addition to form a thick slurry. The specific method includes the following steps:

[0085] Step 1: Divide the materials into the following four material modules and prefabricate them:

[0086] (1) Preparation of ultrafine powder modules: First, the moisture balance of the tobacco leaf module to be ultrafinely pulverized is carried out, and the moisture content is controlled at 11% ± 1%; the pulverization temperature is controlled at ≤ 45°C, the pulverization mesh size is 270 mesh, the moisture content is 7% ± 1%, and the particle size distribution is D90. The mixture is mixed according to the above proportions to prefabricate a 240 kg ultrafine powder module.

[0087] (2) Prefabrication of the auxiliary agent module: chitosan 0.3% and guar gum 0.2% are added to the ultrafine powder module at 0.5% of the absolute dry weight, and the above auxiliary agents are mixed in proportion to form an adhesive module, which is then prefabricated with 68°C production water at a ratio of 1:30 of their absolute dry weight. The prefabrication temperature is 68±2°C, the time is 15 minutes, and the stirring speed is 300 rpm.

[0088] (3) Prefabrication of moisture-proof material module: 0.5% of the absolute dry weight of the ultrafine powder module is added, including 0.3% tamarind polysaccharide and 0.2% beeswax. The above moisture-proof material modules are mixed in proportion to form a moisture-proof material module, and then prefabricated with 70°C production water at a ratio of 1:10 by weight. The prefabrication temperature is 70±2°C, the time is 20 minutes, and the stirring speed is 500 rpm.

[0089] (4) Prefabrication of moisturizing material module: Add 20% of the absolute dry weight of the ultrafine powder module, of which the addition ratio of glycerin is 16% and the addition ratio of propylene glycol is 4%. The above material modules are mixed in proportion and modulated into a moisturizing material module to be used as a smoke agent material; then prefabricate with production water (room temperature) at a ratio of 1:5 by weight, the prefabrication temperature is room temperature, the time is 10 minutes, and the stirring speed is 60 rpm.

[0090] Step 2: Each material module is added step by step and the temperature is increased gradually as follows

[0091] (1) At room temperature, the prepared smoke agent material module and the auxiliary agent module are first mixed and stirred in a prefabricated tank at a speed of 75 rpm for 15 min.

[0092] (2) Add 900 kg of production water to the slurry mixing tank and heat it. When the water temperature in the slurry mixing tank rises to 42±2℃, add the moisturizing material module and the auxiliary agent module mixed in the prefabricated tank to the slurry mixing tank and stir at a speed of 60 rpm and a stirring time of 10 min.

[0093] (3) Continue to heat the material in the slurry mixing tank. When the temperature reaches 57±2℃, add the moisture-proof material module, stir at a speed of 180 rpm, and stir for 10 minutes.

[0094] (4) The material in the slurry mixing tank is continuously heated to 68±2°C and stirred at a constant temperature at a speed of 160-200 rpm for 10-15 min.

[0095] (5) Use a linear powder-liquid dispersing mixer to achieve online mixing of liquid and ultrafine powder, with a rotation speed of 1600 rpm and a liquid discharge deviation of ±0.01m 3 , the powder discharge deviation is ±0.01kg / min; then the dynamically blended thick slurry is transported to the buffer tank using a colloid mill, and designed according to a thick slurry concentration of 20%, and water is replenished using hot water at a temperature of 55±2℃; finally, the thick slurry is homogenized, wherein the thick slurry temperature during the homogenization process is 55±2℃, the stirring speed is 180 rpm, the equilibrium homogenization time is 20min, and the concentration is 25%±1.0%.

[0096] Step 3: After the above thick slurry is balanced, it is subjected to negative pressure and degassing treatment (negative pressure is 0.15Mpa), and then it is mixed with stem leaf paste and spices in proportion to form a coating liquid, and the reconstituted tobacco leaves are coated and dried. During the coating, the amount of coating liquid in the coating tank is strictly controlled, that is, the amount of coating liquid in the coating tank is 5% more than the coating amount (absolute dry).

[0097] Step 4: Comparison of finished product samples

[0098] Finished product samples were taken every three minutes, for a total of 20 samples. The samples were then tested for consistency, basis weight, thickness, and longitudinal tensile strength. Basis weight was measured according to GB / T 451.2-2002, thickness according to GB / T 451.3-2002, and longitudinal tensile strength according to GB / T 12914-2008. The results are as follows.

[0099] Table 3-1 Thick pulp concentration test results (%)

[0100]

[0101] It can be seen from Table 3-1 that after adopting the present invention, the coefficient of variation of the thick slurry concentration prepared by the material in Example 3 is reduced, the range is smaller, the concentration deviation is within ±1.0%, and the stability of the thick slurry quality is significantly improved.

[0102] Table 3-2 Test results of main physical indicators of reconstituted tobacco leaves for heating cigarettes prepared from materials of Comparative Example 3

[0103] index <![CDATA[定量(g / m 2 )]]> Thickness (mm) Longitudinal tensile strength (kN / m) average value 111.65 0.182 1.18 Standard deviation 4.25 0.013 0.18 Coefficient of variation (%) 3.81 7.14 15.25 Maximum 119.67 0.195 1.40 Minimum 104.46 0.160 1.00 Extremely poor 15.21 0.038 0.40

[0104] Table 3-3 Test results of main physical indicators of reconstituted tobacco leaves prepared from materials of Example 3

[0105] index <![CDATA[定量(g / m 2 )]]> Thickness (mm) Longitudinal tensile strength (kN / m) average value 111.14 0.179 1.21 Standard deviation 4.62 0.009 0.13 Coefficient of variation (%) 4.15 5.08 10.74 Maximum 118.84 0.193 1.33 Minimum 104.24 0.160 1.01 Extremely poor 14.60 0.032 0.32

[0106] It can be seen from Tables 3-2 and 3-3 that after adopting the present invention, the coefficient of variation and range of the main physical indicators of the reconstituted tobacco leaves are reduced, and the stability is significantly improved.

Claims

1. A method for preparing a thick slurry for preparing a coating liquid for reconstituted tobacco leaves in a papermaking process, the method comprising the following steps: Step 1: Divide the materials into the following four material modules and prefabricate them separately: Ultrafine powder module prefabrication: prefabricate functional plant materials or tobacco raw materials, mesh size 300-1000 mesh, moisture 8%±1%, particle size distribution ≥D80; temperature during prefabrication ≤45℃; Prefabrication of the additive module: The additives are composed of chitosan and guar gum, wherein the chitosan is added in a proportion of 0.1%-0.5%, and the guar gum is added in a proportion of 0.1%-0.5%, wherein the percentages are based on the absolute dry weight of the ultrafine powder module. The above additives are mixed in proportion to form an additive module, which is then mixed with 20-40 times its weight of water at 65-70°C for 15-20 minutes, and the stirring speed is 300-350 rpm; Prefabrication of moisture-proof material module: The moisture-proof material comprises tamarind polysaccharide and beeswax, wherein the tamarind polysaccharide is added in a proportion of 0.1%-0.5%, and the beeswax is added in a proportion of 0.1%-0.5%, and the percentages are based on the absolute dry weight of the ultrafine powder module. The above moisture-proof materials are mixed in proportion to form a moisture-proof material module, and then mixed with 10-30 times the absolute dry weight of water at 70-75° C. for 20-30 minutes, and the stirring speed is 500-550 rpm; Prefabrication of the moisturizing material module: The moisturizing material comprises glycerin and propylene glycol, wherein the glycerin addition ratio is 0.5%-30%, and the propylene glycol addition ratio is 0.3%-20%. The percentages are based on the absolute dry weight of the ultrafine powder module. The above moisturizing materials are mixed in proportion to form a moisturizing material module, which is then mixed with 5-10 times the absolute dry weight of water at ambient temperature for 5-10 minutes at a stirring speed of 60-70 rpm. Step 2: Each material module is added step by step and the temperature is increased gradually as follows: (1) Mix and stir the prepared moisturizing material module and the auxiliary agent module in a prefabricated tank at room temperature at a stirring speed of 60-80 rpm for 5-10 min; (2) Add a certain amount of production water to the slurry mixing tank and heat it. When the water temperature in the slurry mixing tank rises to 40-45°C, add the moisturizing material module and the auxiliary agent module mixed in the prefabricated tank to the slurry mixing tank and stir at a stirring speed of 50-70 rpm for 5-10 min. (3) Continue to heat the material in the slurry mixing tank. When the temperature reaches 55-60°C, add the moisture-proof material module, stir at a speed of 160-200 rpm, and stir for 10-15 minutes; (4) Continuously heat the material in the slurry mixing tank until the temperature reaches 68±2°C and stir at a constant temperature at a speed of 160-200 rpm for 10-15 min; (5) Using a linear powder-liquid dispersing mixer, the liquid and the ultrafine powder are mixed online at a rotation speed of 1500-2000 rpm; then the dynamically blended thick slurry is transported to a buffer tank by a colloid mill for thick slurry balance homogenization, the temperature in the buffer tank is 50-55°C, the stirring speed is 160-200 rpm, the equilibrium homogenization time is 15-30min, the equilibrium concentration is 10%-30%, and the concentration deviation is ±1.0%, thereby obtaining the thick slurry used for preparing the papermaking method reconstituted tobacco leaf coating liquid.

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