Method for improving peculiar smell of liquid packaging paperboard

Abstract

The invention provides a method for improving peculiar smell of a liquid packaging paperboard. The method comprises the following steps: A) respectively preparing surface layer paper pulp, core layer paper pulp and bottom layer paper pulp; b) respectively adding a wet strength agent, an internal sizing agent AKD, cationic starch and a retention aid into the surface layer paper pulp, the core layer paper pulp and the bottom layer paper pulp; c) respectively filtering water and forming, compounding, squeezing and drying to form a paper blank; sizing the surfaces of the surface layer and the bottom layer of the paper blank by using a surface sizing agent, wherein the surface sizing agent is a mixture of gelatinized starch liquid and an odor inhibitor; and D) drying and calendering again to obtain the liquid packaging paperboard. According to the method, the odor inhibitor is added in the process of preparing the surface layer and the bottom layer, so that the influence of the liquid packaging paperboard on the taste of liquid (such as fresh milk) can be improved, and peculiar smell is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of papermaking, and in particular relates to a method for improving the odor of liquid packaging paperboard. Background Art

[0002] Liquid aseptic packaging materials are mainly used in liquid milk and non-carbonated soft drinks, and their packaging forms mainly include pillow bags, brick bags, combibloc, roof box bags, etc. In recent years, with the rapid development of China's economy and the steady increase in per capita disposable income of residents, my country's consumer goods market has developed well, and the consumption of dairy products and juice has increased significantly. Consumers pay more attention to the impact of packaging on the natural nutrition, freshness and taste of beverages. Roof-type carton packaging can meet the requirements of the majority of dairy or juice processors and end consumers in this regard, making this packaging method generally popular. However, after the roof-type carton packaging paperboards of domestic manufacturers are UV printed and dried and filled with fresh milk, fresh milk is easily reported by consumers to have cardboard, plastic, oil and other odors; because the odor problem of fresh milk in paper packaging has always plagued various dairy companies, further improving the odor problem of roof-type carton packaging paperboards has become a necessity for the development of technology in this field. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a method for improving the odor of liquid packaging paperboard, which method can reduce the odor of liquid packaging paperboard.

[0004] The present invention provides a method for improving the odor of liquid packaging paperboard, comprising the following steps:

[0005] A) preparing a surface layer pulp, a core layer pulp and a bottom layer pulp respectively;

[0006] B) adding a wet strength agent, an internal sizing agent AKD, a cationic starch and a retention aid to the surface layer pulp, the core layer pulp and the bottom layer pulp respectively;

[0007] C) After being respectively drained and formed, compounded, pressed and dried to form paper blanks;

[0008] Applying a surface sizing agent to the surface of the top layer and the bottom layer of the paper blank, wherein the surface sizing agent is a mixture of gelatinized starch liquid and an odor inhibitor;

[0009] D) Liquid packaging paperboard is obtained after further drying and calendering.

[0010] Preferably, the odor suppressant is D-tartaric acid.

[0011] Preferably, the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.2 to 1.2‰.

[0012] Preferably, the concentration of the gelatinized starch solution is 5-6 wt%, and the amount of sizing applied is 1.0-3.0 g / m 2 .

[0013] Preferably, the surface layer pulp ratio is: 40-60% bleached kraft softwood pulp + 60-40% bleached kraft hardwood pulp;

[0014] The core pulp formula is: 25-35% bleached kraft softwood pulp + 5-15% bleached kraft hardwood pulp + 50-70% bleached thermomechanical pulp;

[0015] The bottom pulp formula is: 40-60% bleached sulphate coniferous wood pulp + 60-40% bleached sulphate broadleaf wood pulp.

[0016] Preferably, the wet strength agent is Kymene 777LX;

[0017] The addition amount of the wet strength agent is: 10-13 kg / t for the surface paper layer, 11-16 kg / t for the core paper layer, and 10-13 kg / t for the bottom paper layer.

[0018] Preferably, the sizing agent AKD is Hercon TM 195, the addition amount is: surface paper layer 8-10kg / t, core paper layer 40-45kg / t, bottom paper layer 8-10kg / t.

[0019] Preferably, the cationic starch is Geltron 26, and the addition amount thereof is: 2-3 kg / t for the surface paper layer, 3-5 kg / t for the core paper layer, and 2-3 kg / t for the base paper layer.

[0020] Preferably, the retention aid is Percol TM 182AP and PerForm TM The mixture of SP8275 is added in the following amounts: 0.6-0.8kg / t for the surface paper layer, 0.8-1.0kg / t for the core paper layer, and 0.6-0.8kg / t for the bottom paper layer.

[0021] The present invention provides a method for improving the odor of liquid packaging paperboard, comprising the following steps: A) preparing surface layer pulp, core layer pulp and bottom layer pulp respectively; B) adding wet strength agent, internal sizing agent AKD, cationic starch and retention aid to the surface layer pulp, core layer pulp and bottom layer pulp respectively; C) after filtering and forming respectively, compounding, pressing and drying to form paper blanks; applying surface sizing agent on the surface layer and bottom layer of the paper blank, wherein the surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor; D) obtaining liquid packaging paperboard after drying and calendering again. The above method provided by the present invention can improve the influence of liquid packaging paperboard on the taste of liquid (such as fresh milk) and reduce odor by adding odor inhibitor in the process of preparing the surface layer and bottom layer. DETAILED DESCRIPTION

[0022] The present invention provides a method for improving the odor of liquid packaging paperboard, comprising the following steps:

[0023] A) preparing a surface layer pulp, a core layer pulp and a bottom layer pulp respectively;

[0024] B) adding a wet strength agent, an internal sizing agent AKD, a cationic starch and a retention aid to the surface layer pulp, the core layer pulp and the bottom layer pulp respectively;

[0025] C) After being respectively drained and formed, compounded, pressed and dried to form paper blanks;

[0026] Applying a surface sizing agent to the surface of the top layer and the bottom layer of the paper blank, wherein the surface sizing agent is a mixture of gelatinized starch liquid and an odor inhibitor;

[0027] D) Liquid packaging paperboard is obtained after further drying and calendering.

[0028] The invention prepares the surface layer pulp, the core layer pulp and the bottom layer pulp respectively.

[0029] The ratio of the surface pulp in the present invention is: 40-60wt% bleached kraft softwood pulp (NBKP) + 60-40wt% bleached kraft hardwood pulp (LBKP); the absolute dry mass ratio of bleached kraft softwood pulp to bleached kraft hardwood pulp is specifically 2:3, 11:9, 1:1 or 3:2. In a specific embodiment, the formula of the surface pulp is: 40% NBKP + 60% LBKP; or 55% NBKP + 45% LBKP; or 60% NBKP + 40% LBKP or 50% NBKP + 50% LBKP.

[0030] The core layer pulp ratio of the present invention is: 25-35wt% bleached kraft softwood pulp (NBKP) + 5-15wt% bleached kraft hardwood pulp (LBKP) + 50-70wt% bleached thermomechanical pulp (BCTMP). In a specific embodiment, the core layer pulp formula is: 25% NBKP + 15% LBKP + 60% BCTMP; 30% NBKP + 5% LBKP + 65% BCTMP; 25% NBKP + 5% LBKP + 70% BCTMP; 35% NBKP + 15% LBKP + 50% BCTMP; 30% NBKP + 8% LBKP + 62% BCTMP; or 32% NBKP + 10% LBKP + 58% BCTMP.

[0031] The bottom pulp ratio in the present invention is: 40-60wt% white kraft softwood pulp + 60-40wt% bleached kraft hardwood pulp; the absolute dry weight ratio of bleached kraft softwood pulp to bleached kraft hardwood pulp is specifically 2:3, 11:9, 1:1 or 3:2. In a specific embodiment, the bottom pulp ratio is: 40% NBKP + 60% LBKP; or 55% NBKP + 45% LBKP; or 60% NBKP + 40% LBKP or 50% NBKP + 50% LBKP.

[0032] The present invention adds wet strength agent, internal sizing agent AKD, cationic starch and retention aid to the surface layer pulp, core layer pulp and bottom layer pulp respectively. In the present invention, the wet strength agent is Kymene777LX, and the addition amount is: 10-13kg / t for the surface paper layer, specifically 10kg / t, 11kg / t, 12kg / t or 13kg / t; 11-16kg / t for the core paper layer, specifically 11kg / t, 12kg / t, 13kg / t, 14kg / t, 15kg / t or 16kg / t; 10-13kg / t for the bottom paper layer, specifically 10kg / t, 11kg / t, 12kg / t or 13kg / t.

[0033] The sizing agent AKD is Hercon TM 195, the addition amount is: 8-10kg / t for the surface paper layer, specifically 8kg / t, 9kg / t or 10kg / t; 40-45kg / t for the core paper layer, specifically 40kg / t, 41kg / t, 42kg / t, 43kg / t, 44kg / t or 45kg / t; 8-10kg / t for the bottom paper layer, specifically 8kg / t, 9kg / t or 10kg / t.

[0034] The cationic starch is Geltron 26, and its addition amount is: 2-3kg / t for the surface paper layer, specifically 2kg / t or 3kg / t; 3-5kg / t for the core paper layer, specifically 3kg / t, 4kg / t or 5kg / t; 2-3kg / t for the base paper layer, specifically 2kg / t or 3kg / t.

[0035] The retention agent is Percol TM 182AP and PerForm TM SP8275 mixture, Percol TM 182AP and PerForm TM The mass ratio of SP8275 is 1:1; the addition amount of the retention aid is: 0.6-0.8kg / t for the surface paper layer, specifically 0.6kg / t, 0.7kg / t or 0.8kg / t; 0.8-1.0kg / t for the core paper layer, specifically 0.8kg / t, 0.9kg / t or 1.0kg / t; 0.6-0.8kg / t for the bottom paper layer, specifically 0.6kg / t, 0.7kg / t or 0.8kg / t.

[0036] The present invention respectively filters the surface layer pulp, core layer pulp and bottom layer pulp after adding the above materials, forms them, and then compounds, presses and dries them to form paper blanks. The three-layer composite forming method in the present invention is three-layer stacking net forming. Specifically, the present invention respectively screens and removes the residue of the surface layer pulp, core layer pulp and bottom layer pulp after adding the materials, and then feeds them into the surface layer headbox, core layer headbox and bottom layer headbox of the stacking net papermaking machine, and then forms the base paper with the surface layer, core layer and bottom layer after the three-layer stacking net forming of the stacking net papermaking machine.

[0037] In the present invention, the vehicle speed is 420-450 m / min. During compounding, based on the sum of the mass of the surface layer, the core layer and the bottom layer, the surface layer slurry accounts for 18-19.5%, the core layer slurry accounts for 63-64.5%, and the bottom layer slurry accounts for 16.5-17.5%.

[0038] In the present invention, the pressing is divided into three pressures, wherein the first pressure is 696-702 kN / m, the second pressure is 734-741 kN / m, and the third pressure is 37-40 kN / m. The drying pressure after pressing is 2.0-2.8 bar.

[0039] The present invention adopts a surface sizing agent to apply sizing on the surface layer and the bottom layer of the paper blank, wherein the surface sizing agent is a mixture of gelatinized starch liquid and an odor inhibitor, the concentration of the gelatinized starch liquid is 5-6wt%, specifically 5wt%, 5.1wt%, 5.2wt%, 5.3wt%, 5.4wt%, 5.5wt%, 5.6wt%, 5.7wt%, 5.8wt%, 5.9wt% or 6.0wt%; the sizing amount calculated on the basis of dry starch is 1.0-3.0g / m 2 , specifically 1.0g / m 2 , 1.1g / m 2 , 1.2g / m 2 , 1.3g / m 2 , 1.4g / m 2 , 1.5g / m 2 , 1.6g / m 2 , 1.7g / m 2 , 1.8g / m 2 , 1.9g / m 2 , 2.0g / m 2 , 2.1g / m 2 , 2.2g / m 2 , 2.3g / m 2 , 2.4g / m 2 , 2.5g / m 2 , 2.6g / m 2 , 2.7g / m 2 , 2.8g / m 2 , 2.9g / m 2 or 3g / m 2 The odor inhibitor is D-tartaric acid (FCA0516 in the GB9685 catalog). The sizing amount in the present invention is 1.0 to 3.0 g / m 2 The meaning is: the amount of glue used per square meter of paper, including the upper and lower surfaces of the paper blank, also called the surface layer and the bottom layer, and the sum of the amounts of glue applied respectively.

[0040] The mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is preferably 0.2-1.2‰, specifically 0.2‰, 0.3‰, 0.4‰, 0.5‰, 0.6‰, 0.7‰, 0.8‰, 0.9‰, 1.0‰ or 1.2‰.

[0041] The present invention obtains liquid packaging paperboard after re-drying and calendering. The steam pressure used for re-drying in the present invention is 0.6-2.7 bar. The calendering in the present invention includes hard calendering and soft calendering; the pressure of the hard calendering is 38-56 KN / m and the temperature is 230°C; the pressure of the soft calendering is 20 KN / m and the temperature is 50-74°C.

[0042] The present invention performs VOC detection on the above liquid packaging paperboard, including methanol (alcohol smell), ethanol (alcohol smell), n-propanol (alcohol smell), acetone (mint smell), isopropyl ketone (mint smell), cyclohexanone (earth smell) and styrene (plastic oil smell). The test method used for VOC detection in the present invention is YC / T207.

[0043] In order to further illustrate the present invention, a method for improving the odor of liquid packaging paperboard provided by the present invention is described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0044] In the following case, the wet strength agent is Kymene 777LX, the cationic starch is Geltron 26, and the retention aid is Percol TM 182AP and PerForm TM The mixture of SP8275 and the ratio of the two is 1:1.

[0045] Example 1

[0046] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0047] 1. Slurry preparation and wet-end forming

[0048] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0049] ①Surface pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.8kg / t;

[0050] ② Core pulp: 25% NBKP + 15% LBKP + 60% BCTMP; wet strength agent addition: 13.5kg / t, internal sizing agent AKD addition: 43kg / t, cationic starch addition: 4kg / t, retention agent addition: 0.9kg / t;

[0051] ③ Bottom pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.8kg / t;

[0052] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0053] 2. Paper machine section

[0054] ①Speed: 427m / min;

[0055] ②Surface layer slurry ratio: 19.1%, core layer slurry ratio 63.4%, bottom layer slurry ratio 17.5%;

[0056] ③ Pressing: 1st press pressure 699kN / m, 2nd press pressure 741kN / m, 3rd press pressure 37kN / m;

[0057] ④Pre-drying: steam pressure 2.0 bar;

[0058] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.5%, and the surface sizing amount is 1.5g / m based on dry starch. 2 , the glue amount on the lower surface is 1.5g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.2‰;

[0059] ⑥ Post-drying: steam pressure 0.6 bar;

[0060] ⑦Hard calendering: pressure 38kN / m, temperature 230℃;

[0061] ⑧Soft calendering: pressure 20kN / m, temperature 74℃;

[0062] ⑨Coiling, rewinding, packaging and storage.

[0063] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 1:

[0064] Table 1 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 1

[0065]

[0066] Example 2

[0067] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0068] 1. Slurry preparation and wet end forming

[0069] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0070] ①Surface pulp: 50% NBKP + 50% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 8kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.6kg / t;

[0071] ② Core pulp: 30% NBKP + 5% LBKP + 65% BCTMP; wet strength agent addition: 16kg / t, internal sizing agent AKD addition: 45kg / t, cationic starch addition: 5kg / t, retention agent addition: 1.0kg / t;

[0072] ③ Bottom pulp: 50% NBKP + 50% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 8kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.6kg / t;

[0073] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0074] 2. Paper machine section

[0075] ①Speed: 427m / min;

[0076] ②Surface layer slurry ratio: 18.8%, core layer slurry ratio 63.9%, bottom layer slurry ratio 17.3%;

[0077] ③ Pressing: 1st press pressure 702kN / m, 2nd press pressure 741kN / m, 3rd press pressure 37kN / m;

[0078] ④Pre-drying: steam pressure 2.1 bar;

[0079] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 6.0%, and the surface sizing amount is 1.0g / m based on dry starch. 2 , the glue amount on the lower surface is 1.0g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.7‰;

[0080] ⑥ Post-drying: steam pressure 0.6 bar;

[0081] ⑦Hard calendering: pressure 40kN / m, temperature 230℃;

[0082] ⑧Soft calendering: pressure 20kN / m, temperature 60℃;

[0083] ⑨Coiling, rewinding, packaging and storage.

[0084] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 2:

[0085] Table 2 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 2

[0086]

[0087] Example 3

[0088] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0089] 1. Slurry preparation and wet-end forming

[0090] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0091] ①Surface pulp: 60% NBKP + 40% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 10kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.7kg / t;

[0092] ② Core pulp: 25% NBKP+5% LBKP+70% BCTMP; wet strength agent addition: 16kg / t, internal sizing agent AKD addition: 45kg / t, cationic starch addition: 5kg / t, retention agent addition: 1.0kg / t;

[0093] ③ Bottom pulp: 60% NBKP + 40% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 10kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.7kg / t;

[0094] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0095] 2. Paper machine section

[0096] ①Speed: 445m / min;

[0097] ②Surface layer slurry ratio: 18.5%, core layer slurry ratio 64.5%, bottom layer slurry ratio 16.9%;

[0098] ③ Pressing: 1st press pressure 699kN / m, 2nd press pressure 734kN / m, 3rd press pressure 40kN / m;

[0099] ④Pre-drying: steam pressure 2.8 bar;

[0100] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.0%, and the surface sizing amount calculated on dry starch is 0.8g / m 2 , the glue amount on the lower surface is 0.8g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 1.2‰;

[0101] ⑥ Post-drying: steam pressure 2.7 bar;

[0102] ⑦Hard calendering: pressure 56kN / m, temperature 230℃;

[0103] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0104] ⑨Coiling, rewinding, packaging and storage.

[0105] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 3:

[0106] Table 3 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 3

[0107]

[0108] Example 4

[0109] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0110] 1. Slurry preparation and wet-end forming

[0111] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0112] ①Surface pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 13kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.6kg / t;

[0113] ② Core pulp: 35% NBKP + 15% LBKP + 50% BCTMP; wet strength agent addition: 11kg / t, internal sizing agent AKD addition: 40kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.8kg / t;

[0114] ③ Bottom pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 13kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.6kg / t;

[0115] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0116] 2. Paper machine section

[0117] ①Speed: 445m / min;

[0118] ②Surface layer slurry ratio: 18.6%, core layer slurry ratio 64.4%, bottom layer slurry ratio 17.0%;

[0119] ③ Pressing: 1st press pressure 699kN / m, 2nd press pressure 739kN / m, 3rd press pressure 40kN / m;

[0120] ④Pre-drying: steam pressure 2.8 bar;

[0121] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.5%, and the surface sizing amount is 1.2g / m based on dry starch. 2 , the glue amount on the lower surface is 1.2g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.8‰;

[0122] ⑥ Post-drying: steam pressure 2.2 bar;

[0123] ⑦Hard calendering: pressure 40kN / m, temperature 230℃;

[0124] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0125] ⑨Coiling, rewinding, packaging and storage.

[0126] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 4:

[0127] Table 4 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 4

[0128]

[0129] Example 5

[0130] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0131] 1. Slurry preparation and wet end forming

[0132] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0133] ①Surface pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 10kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.6kg / t;

[0134] ② Core pulp: 30% NBKP + 8% LBKP + 62% BCTMP; wet strength agent addition: 15kg / t, internal sizing agent AKD addition: 44kg / t, cationic starch addition: 5kg / t, retention agent addition: 1.0kg / t;

[0135] ③ Bottom pulp: 60% NBKP + 40% LBKP; wet strength agent addition: 10kg / t, internal sizing agent AKD addition: 8kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.8kg / t;

[0136] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0137] 2. Paper machine section

[0138] ①Speed: 445m / min;

[0139] ②Surface layer slurry ratio: 18.7%, core layer slurry ratio 64.1%, bottom layer slurry ratio 17.2%;

[0140] ③ Pressing: 1st press pressure 696kN / m, 2nd press pressure 741kN / m, 3rd press pressure 40kN / m;

[0141] ④Pre-drying: steam pressure 2.7 bar;

[0142] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.0%, and the surface sizing amount is 0.5g / m based on dry starch. 2 , the glue amount on the lower surface is 0.5g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.4‰;

[0143] ⑥ Post-drying: steam pressure 1.7 bar;

[0144] ⑦Hard calendering: pressure 56kN / m, temperature 230℃;

[0145] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0146] ⑨Coiling, rewinding, packaging and storage.

[0147] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 5:

[0148] Table 5 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 5

[0149]

[0150] Example 6

[0151] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0152] 1. Slurry preparation and wet end forming

[0153] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0154] ①Surface pulp: 55% NBKP + 45% LBKP; wet strength agent addition: 11.5kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.7kg / t;

[0155] ② Core pulp: 32% NBKP + 10% LBKP + 58% BCTMP; wet strength agent addition: 14kg / t, internal sizing agent AKD addition: 41kg / t, cationic starch addition: 4kg / t, retention agent addition: 0.9kg / t;

[0156] ③ Bottom pulp: 55% NBKP + 45% LBKP; wet strength agent addition: 11.5kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.7kg / t;

[0157] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0158] 2. Paper machine section

[0159] ①Speed: 445m / min;

[0160] ②Surface layer slurry ratio: 18.5%, core layer slurry ratio 64.5%, bottom layer slurry ratio 17.0%;

[0161] ③ Pressing: 1st press pressure 699kN / m, 2nd press pressure 735kN / m, 3rd press pressure 40kN / m;

[0162] ④Pre-drying: steam pressure 2.9 bar;

[0163] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 6.0%, and the surface sizing amount calculated on dry starch is 1.3g / m 2 , the glue amount on the lower surface is 1.3g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.8‰;

[0164] ⑥ Post-drying: steam pressure 2.2 bar;

[0165] ⑦Hard calendering: pressure 53kN / m, temperature 230℃;

[0166] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0167] ⑨Coiling, rewinding, packaging and storage.

[0168] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 6:

[0169] Table 6 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 6

[0170]

[0171] Example 7

[0172] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0173] 1. Slurry preparation and wet-end forming

[0174] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0175] ①Surface pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.6kg / t;

[0176] ② Core pulp: 30% NBKP + 5% LBKP + 65% BCTMP; wet strength agent addition: 13kg / t, internal sizing agent AKD addition: 42kg / t, cationic starch addition: 5kg / t, retention agent addition: 0.8kg / t;

[0177] ③ Bottom pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.6kg / t;

[0178] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0179] 2. Paper machine section

[0180] ①Speed: 445m / min;

[0181] ②Surface layer slurry ratio: 18.5%, core layer slurry ratio 64.3%, bottom layer slurry ratio 17.2%;

[0182] ③ Pressing: 1st press pressure 698kN / m, 2nd press pressure 740kN / m, 3rd press pressure 40kN / m;

[0183] ④Pre-drying: steam pressure 2.7 bar;

[0184] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.5%, and the surface sizing amount is 1.3g / m based on dry starch. 2 , the glue amount on the lower surface is 1.3g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.1‰;

[0185] ⑥ Post-drying: steam pressure 1.5 bar;

[0186] ⑦Hard calendering: pressure 40kN / m, temperature 230℃;

[0187] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0188] ⑨Coiling, rewinding, packaging and storage.

[0189] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 7:

[0190] Table 7 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 7

[0191]

[0192] Example 8

[0193] A preparation process for improving the odor of liquid packaging paperboard comprises the following steps:

[0194] 1. Slurry preparation and wet-end forming

[0195] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0196] ①Surface pulp: 55% NBKP + 45% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.8kg / t;

[0197] ② Core pulp: 30% NBKP+5% LBKP+65% BCTMP; wet strength agent addition: 15kg / t, internal sizing agent AKD addition: 44kg / t, cationic starch addition: 5kg / t, retention agent addition: 1.0kg / t;

[0198] ③ Bottom pulp: 55% NBKP + 45% LBKP; wet strength agent addition: 12kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 2kg / t, retention agent addition: 0.8kg / t;

[0199] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0200] 2. Paper machine section

[0201] ①Speed: 445m / min;

[0202] ②Surface layer slurry ratio: 18.8%, core layer slurry ratio 64.1%, bottom layer slurry ratio 17.1%;

[0203] ③ Pressing: 1st press pressure 699kN / m, 2nd press pressure 738kN / m, 3rd press pressure 40kN / m;

[0204] ④Pre-drying: steam pressure 2.8 bar;

[0205] ⑤ Surface sizing: The surface sizing agent is a mixture of gelatinized starch liquid and odor inhibitor, the mass percentage concentration of the gelatinized starch liquid is 5.0%, and the surface sizing amount calculated on dry starch is 1.0g / m 2 , the glue amount on the lower surface is 1.0g / m 2 , the mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 1.5‰;

[0206] ⑥ Post-drying: steam pressure 2.2 bar;

[0207] ⑦Hard calendering: pressure 50kN / m, temperature 230℃;

[0208] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0209] ⑨Coiling, rewinding, packaging and storage.

[0210] The low-odor liquid packaging paperboard prepared in this example was tested for odor molecules VOC, and the results are shown in Table 8:

[0211] Table 8 VOC content of odor molecules in low odor liquid packaging paperboard obtained in Example 8

[0212]

[0213] Comparative Example 1

[0214] Preparation process of ordinary liquid packaging paperboard:

[0215] 1. Slurry preparation and wet-end forming

[0216] After the pulp or fresh pulp is pulped by the hydraulic pulper, the surface, core and bottom layers are prepared separately:

[0217] ①Surface pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 11.5kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.7kg / t;

[0218] ② Core pulp: 30% NBKP + 10% LBKP + 60% BCTMP; wet strength agent addition: 13.5kg / t, internal sizing agent AKD addition: 41kg / t, cationic starch addition: 4kg / t, retention agent addition: 0.9kg / t;

[0219] ③ Bottom pulp: 40% NBKP + 60% LBKP; wet strength agent addition: 11.5kg / t, internal sizing agent AKD addition: 9kg / t, cationic starch addition: 3kg / t, retention agent addition: 0.7kg / t;

[0220] The surface layer pulp, core layer pulp and bottom layer pulp are respectively screened and deslagging and sent to the surface layer headbox, core layer headbox and bottom layer headbox of the stacked paper machine. After three-layer stacking forming of the stacked paper machine, base paper with a surface layer, a core layer and a bottom layer is obtained.

[0221] 2. Paper machine section

[0222] ①Speed: 445m / min;

[0223] ②Surface layer slurry ratio: 18.5%, core layer slurry ratio 64.5%, bottom layer slurry ratio 17.0%;

[0224] ③ Pressing: 1st press pressure 698kN / m, 2nd press pressure 735kN / m, 3rd press pressure 40kN / m;

[0225] ④Pre-drying: steam pressure 2.8 bar;

[0226] ⑤ Surface sizing: The surface sizing agent is gelatinized starch liquid, the mass percentage concentration of the gelatinized starch liquid is 5.5%, and the surface sizing amount calculated on dry starch is 1.0g / m 2 , the glue amount on the lower surface is 1.0g / m 2 ;

[0227] ⑥ Post-drying: steam pressure 2.1 bar;

[0228] ⑦Hard calendering: pressure 55kN / m, temperature 230℃;

[0229] ⑧Soft calendering: pressure 20kN / m, temperature 50℃;

[0230] ⑨Coiling, rewinding, packaging and storage.

[0231] The low odor liquid packaging paperboard prepared in the comparative example was subjected to odor molecule VOC detection, and the results are shown in Table 9:

[0232] Table 9 Odor molecule VOC content of low odor liquid packaging paperboard obtained in comparative example

[0233]

[0234] It can be seen from the above embodiments that the present invention significantly reduces the content of easily detectable odor molecules that affect the taste of milk in the gable-top paper box packaging paperboard by adding D-tartaric acid, an odor inhibitor with antioxidant effect, into the surface sizing agent; the odor molecules include: methanol, ethanol, and n-propanol with alcohol flavor, acetone and isopropanol with mint flavor, cyclohexanone with earthy smell, and styrene with plastic engine oil flavor. The test results show that the content of methanol with alcohol flavor in the liquid packaging paperboard prepared by the method provided by the present invention is 1.1223-1.3361 ppm, the content of ethanol is 0.1180-0.1765 ppm, the content of n-propanol is 0.0003-0.0026 ppm; the content of acetone with mint flavor is 0.0599-0.0883 ppm; the content of isopropanol with mint flavor is 0.0009-0.0087 ppm; the content of cyclohexanone with earthy flavor is 0.0008-0.0038 ppm; the content of styrene with plastic engine oil flavor is 0.0054-0.0129 ppm; and the total content is 1.3696-1.5775 ppm.

[0235] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving the odor of liquid packaging paperboard, comprising the following steps: A) preparing a surface layer pulp, a core layer pulp and a bottom layer pulp respectively; B) adding a wet strength agent, an internal sizing agent AKD, a cationic starch and a retention aid to the surface layer pulp, the core layer pulp and the bottom layer pulp respectively; C) After being respectively drained and formed, compounded, pressed and dried to form paper blanks; Applying a surface sizing agent to the surface of the top layer and the bottom layer of the paper blank, wherein the surface sizing agent is a mixture of gelatinized starch liquid and an odor inhibitor; D) Liquid packaging paperboard is obtained after further drying and calendering.

2. The method according to claim 1, characterized in that The odor suppressant is D-tartaric acid.

3. The method according to claim 2, characterized in that The mass percentage of the odor inhibitor relative to the absolute dry starch in the starch gelatinization liquid is 0.2 to 1.2‰.

4. The method according to claim 1, characterized in that: The concentration of the gelatinized starch solution is 5-6 wt%, and the amount of sizing applied is 1.0-3.0 g / m 2 .

5. The method according to claim 1, characterized in that The surface layer pulp formula is: 40-60% bleached sulphate softwood pulp + 60-40% bleached sulphate hardwood pulp; The core pulp formula is: 25-35% bleached kraft softwood pulp + 5-15% bleached kraft hardwood pulp + 50-70% bleached thermomechanical pulp; The bottom pulp formula is: 40-60% bleached sulphate coniferous wood pulp + 60-40% bleached sulphate broadleaf wood pulp.

6. The method according to claim 1, characterized in that The wet strength agent is Kymene777LX; The addition amount of the wet strength agent is: 10-13 kg / t for the surface paper layer, 11-16 kg / t for the core paper layer, and 10-13 kg / t for the bottom paper layer.

7. The method according to claim 1, characterized in that The sizing agent AKD is Hercon TM 195, the addition amount is: surface paper layer 8-10kg / t, core paper layer 40-45kg / t, bottom paper layer 8-10kg / t.

8. The method according to claim 1, characterized in that The cationic starch is Geltron26, and the addition amount thereof is: 2-3 kg / t for the surface paper layer, 3-5 kg / t for the core paper layer, and 2-3 kg / t for the bottom paper layer.

9. The method according to claim 1, characterized in that: The retention agent is Percol TM 182AP and PerForm TM The mixture of SP8275 is added in the following amounts: 0.6-0.8kg / t for the surface paper layer, 0.8-1.0kg / t for the core paper layer, and 0.6-0.8kg / t for the bottom paper layer.

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