Method for preventing yellowing of cigarette white board and detection method

Abstract

The application discloses a method for preventing cigarette white cardboard from yellowing, which prevents the cigarette white cardboard from yellowing by controlling the surface-core layer gram weight ratio of the cigarette white cardboard, and the surface-core layer gram weight ratio ranges from 0.6 to 1.1; and the application also provides a detection method for the surface-core layer gram weight ratio of the cigarette white cardboard. The method for preventing the cigarette white cardboard from yellowing and the detection method are simple and easy to operate, and the cigarette white cardboard can be prevented from yellowing by controlling the surface-core layer gram weight ratio.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cigarette paper, in particular to a method for preventing cigarette white cardboard from yellowing and a detection method. BACKGROUND

[0002] Cigarette cardboard is one of important varieties in cigarette packaging paper, and quality control of the cigarette cardboard is also a problem that is paid close attention to by the tobacco industry. Many quality indexes need to be controlled for the cigarette cardboard, including basis weight, thickness, basis weight difference, thickness difference, stiffness, tightness, whiteness, gloss, smoothness, moisture, interlayer bonding strength, dust degree, color phase, warping and the like. In addition to the physical strength indexes, the apparent properties of the cigarette cardboard are the indexes that are paid close attention to by the tobacco industry, and the whiteness is one of the important apparent properties. However, the cigarette cardboard is prone to yellowing in the use process, thereby causing the decrease of the whiteness of the paper.

[0003] The quality control system of the cigarette white cardboard is relatively complex, and multiple disciplines are involved. The attention of the tobacco industry to the cigarette white cardboard is mainly focused on the use performance. As the packaging paper, the apparent properties of the cigarette cardboard are one of important performance indexes thereof. In the long-term use process, the cigarette cardboard is prone to yellowing, thereby causing the decrease of the whiteness and affecting the apparent properties. Therefore, how to control the decrease of the whiteness and avoid the yellowing is particularly important. SUMMARY

[0004] To solve the above technical problems, the application provides a method for preventing cigarette white cardboard from yellowing and a detection method, which are simple and easy to operate, and the cigarette white cardboard can be prevented from yellowing by controlling the grammage ratio of the surface layer and the core layer of the cigarette white cardboard.

[0005] The technical scheme provided by the application is as follows.

[0006] A method for preventing cigarette white cardboard from yellowing, which prevents the cigarette white cardboard from yellowing by controlling the grammage ratio of the surface layer and the core layer of the cigarette white cardboard, and the grammage ratio of the surface layer and the core layer is 0.6-1.1.

[0007] Preferably, the grammage ratio of the surface layer and the core layer is 0.7-1.

[0008] Preferably, the cigarette white cardboard is cigarette strip and box packaging printing product base paper, the surface layer of the cigarette white cardboard is sulfate wood pulp, and the core layer of the cigarette white cardboard is wood pulp with a lignin content of not less than 80%.

[0009] A detection method for the grammage ratio of the surface layer and the core layer of cigarette white cardboard, comprising the following steps.

[0010] S1, immersing a paper sample of the cigarette white cardboard in a solvent at a certain temperature for a certain time and then taking out;

[0011] S2, separating the paper sample into surface, core and bottom layers;

[0012] S3, drying the separated layers (at room temperature, naturally dried) and placing them together with the intact paper sample in a constant temperature and humidity environment until the mass is constant;

[0013] S4, weighing the mass of each layer of the paper sample and the mass of the intact paper sample, and calculating the gram weight ratio of the surface and core layers.

[0014] Preferably, the solvent used in step S1 is water.

[0015] Preferably, the treatment temperature in step S1 is 20-30°C, and the soaking time is 48-72h.

[0016] Preferably, the separation process in step S2 should be slow and forceful in the same direction to ensure that the fibers of each layer are completely separated as much as possible without sticking to each other.

[0017] Preferably, the temperature of the constant temperature and humidity environment in step S3 is 23±1°C, and the humidity is 50±2%.

[0018] Preferably, the formula for calculating the gram weight ratio of the surface and core layers in step S4 is (surface layer + bottom layer) ÷ core layer × 100%.

[0019] The mechanism of the present application is as follows: the cigarette white card generally has a three-layer structure, namely, a surface layer, a core layer and a bottom layer. Because of the requirement of whiteness index of the white card, the fibers of the surface layer and the bottom layer are generally good, and generally sulfite wood pulp is used, which belongs to chemical pulping, so the lignin content is low; and the core layer is inside the paper, so the manufacturer often chooses general quality fibers for the core layer in order to save cost, which is mainly chemical mechanical groundwood pulp, and the yield of wood of this kind of pulp is high (85%~90%), and the production cost is relatively low, but the lignin content is relatively high. Although lignin exists in the form of colorless alkyl phenol in the paper fibers during the production process of the cigarette white card, after a long time of oxidation, lignin will form quinone structure, thus showing yellow color, which will affect the physical properties of the white card, leading to yellowing of the white card. In order to more effectively control the quality of the white card (a large number of studies have been carried out by the prior art personnel, and the methods mainly adopted are: the first type is to prevent the contact of light wave and photosensitive component-lignin, which can be achieved by adding ultraviolet absorber or coating treatment of the paper; the second type is chemical modification of lignin functional group to prevent the formation of active reaction intermediates; and the last type is to eliminate active free radicals that can lead to the production of chromogenic groups, such as adding inactivators and antioxidants. At present, although there are relatively many studies on yellowing inhibition technology, most of them cannot be applied in practice due to the limitation of cost and other factors. Based on the analysis of the paper fiber composition, the present application can effectively solve the yellowing problem of the cigarette white card by controlling the basis weight ratio of the surface layer and the core layer of the cigarette white card, and it is necessary to develop the detection technology standard of the basis weight ratio of the surface layer and the core layer of the cigarette white card.

[0020] By studying the separation method of the surface layer, the core layer and the bottom layer of the cigarette white card, analyzing the influence of the soaking liquid and the treatment condition on the layering effect, establishing the detection technology standard of the layer separation of the cigarette white card, the understanding and recognition of the layer structure and the interlayer bonding force of the cigarette card can be further deepened. The further establishment of the detection method of the basis weight ratio of the surface layer and the core layer can build the relationship between the basis weight ratio of the surface layer and the core layer and the whiteness, the yellowing value and the related quality indexes of the cigarette white card, find the suitable threshold range of the basis weight ratio of the surface layer and the core layer, so as to control the quality of the cigarette card purchased by the enterprise in advance, and avoid a series of quality problems such as decrease of whiteness and yellowing in the subsequent production process.

[0021] The present application has the following advantages over the prior art:

[0022] The method for preventing yellowing of the cigarette white card of the present application finds the reasonable interval range of the basis weight ratio of the surface layer and the core layer of the cigarette white card by establishing the correlation between the basis weight ratio of the surface layer and the core layer and the yellowing of the cigarette white card, thereby providing certain theoretical support for the quality control of the cigarette white card, which can effectively solve the yellowing problem of the cigarette white card. The establishment of the method for preventing yellowing of the cigarette white card of the present application is beneficial to solving the specific problems in the production of enterprises, and has important theoretical and practical significance. DETAILED DESCRIPTION

[0023] In order for those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0024] The embodiment of the present application provides a method for preventing yellowing of white cardboard for cigarettes. The method controls the surface-core layer grammage ratio of the white cardboard for cigarettes to prevent yellowing of the white cardboard for cigarettes. The surface-core layer grammage ratio ranges from 0.6 to 1.1, and preferably ranges from 0.7 to 1.

[0025] In the embodiment, the white cardboard for cigarettes is a cigarette carton printing paper. The surface layer of the white cardboard for cigarettes is made of sulfate wood pulp, and the core layer of the white cardboard for cigarettes is made of wood pulp with a lignin content of not less than 80%.

[0026] A method for detecting the surface-core layer grammage ratio of white cardboard for cigarettes includes the following steps:

[0027] S1, soaking a paper sample of the white cardboard for cigarettes in a solvent at a certain temperature for a certain time, and then taking out the paper sample;

[0028] S2, separating the paper sample into surface, core and bottom layers;

[0029] S3, drying the separated layers of the paper sample and placing the dried layers and the complete paper sample in a constant temperature and humidity environment until the mass is constant;

[0030] S4, weighing the mass of each layer of the paper sample and the mass of the complete paper sample, and calculating the surface-core layer grammage ratio.

[0031] In the embodiment, the solvent used in step S1 is water, the treatment temperature is 20-30°C, and the soaking time is 48-72h.

[0032] In the embodiment, the separation process of step S2 should be slow and forceful in the same direction to ensure that the fibers of each layer are completely separated without mutual adhesion.

[0033] In the embodiment, the temperature of the constant temperature and humidity environment in step S3 is 23±1°C, and the humidity is 50±2%.

[0034] In the embodiment, the formula for calculating the surface-core layer grammage ratio in step S4 is (surface layer + bottom layer) ÷ core layer × 100%.

[0035] The following are specific embodiments:

[0036] Example 1

[0037] A method for preventing yellowing of cigarette white cardboard, which prevents yellowing of cigarette white cardboard by controlling the basis weight ratio of the surface core layer of cigarette white cardboard, and a method for detecting the basis weight ratio of the surface core layer of cigarette white cardboard, comprising the following steps:

[0038] (1) Soak the paper sample in water for 48 hours or more at a water temperature of 25°C;

[0039] (2) After taking it out, use a water-absorbing paper to absorb the excess water;

[0040] (3) Separate the layers according to the surface, core, and bottom using tweezers, and slowly apply force in the same direction during the separation process to ensure that the fibers of each layer are completely separated and do not adhere to each other;

[0041] (4) Dry the separated layers of the paper sample and place them together with the intact paper sample in a constant temperature and humidity laboratory [(23±1)℃, (50±2)%] for 24 hours or more for standby;

[0042] (5) Measure the mass of each layer using an analytical balance;

[0043] (6) Calculate the basis weight ratio of the surface and core layers according to the formula.

[0044] Repeat the test 5 times and take the average value. Calculation shows that the basis weight ratio of the surface and core layers in this example is 0.8.

[0045] Example 2

[0046] A method for preventing yellowing of cigarette white cardboard, which prevents yellowing of cigarette white cardboard by controlling the basis weight ratio of the surface core layer of cigarette white cardboard, and a method for detecting the basis weight ratio of the surface core layer of cigarette white cardboard, comprising the following steps:

[0047] (1) Soak the paper sample in water for 48 hours or more at a water temperature of 25°C;

[0048] (2) After taking it out, use a water-absorbing paper to absorb the excess water;

[0049] (3) Separate the layers according to the surface, core, and bottom using tweezers, and slowly apply force in the same direction during the separation process to ensure that the fibers of each layer are completely separated and do not adhere to each other;

[0050] (4) Dry the separated layers of the paper sample and place them together with the intact paper sample in a constant temperature and humidity laboratory [(23±1)℃, (50±2)%] for 24 hours or more for standby;

[0051] (5) Measure the mass of each layer using an analytical balance;

[0052] (6) Calculate the basis weight ratio of the surface and core layers according to the formula.

[0053] Repeat the test 5 times, take the average value, calculate that the surface, core layer of this embodiment is 0.9.

[0054] Example 3:

[0055] A method for preventing cigarette white cardboard from yellowing, by controlling the surface, core layer of cigarette white cardboard gram weight ratio to prevent cigarette white cardboard from yellowing, the detection method of the surface, core layer of cigarette white cardboard gram weight ratio, comprising the following steps:

[0056] (1) Put the paper sample in water for more than 48h, water temperature is 25℃;

[0057] (2) After taking out, use water absorption paper to absorb the excess water;

[0058] (3) Use tweezers to separate according to the surface, core and bottom layers, and the separation process should be slow and forceful along the same direction, so as to ensure that the fibers of each layer are completely separated and not adhered to each other;

[0059] (4) After drying the separated layers, put them together with the complete paper sample into a constant temperature and humidity laboratory [(23±1)℃, (50±2)%] for more than 24h for standby;

[0060] (5) Measure the mass of each layer with an analytical balance;

[0061] (6) Calculate the surface, core layer gram weight ratio according to the formula.

[0062] Repeat the test 5 times, take the average value, calculate that the surface, core layer of this embodiment is 1.0.

[0063] Comparative example 1:

[0064] A method for preventing cigarette white cardboard from yellowing, by controlling the surface, core layer of cigarette white cardboard gram weight ratio to prevent cigarette white cardboard from yellowing, the detection method of the surface, core layer of cigarette white cardboard gram weight ratio, comprising the following steps:

[0065] (1) Put the paper sample in water for more than 48h, water temperature is 25℃;

[0066] (2) After taking out, use water absorption paper to absorb the excess water;

[0067] (3) Use tweezers to separate according to the surface, core and bottom layers, and the separation process should be slow and forceful along the same direction, so as to ensure that the fibers of each layer are completely separated and not adhered to each other;

[0068] (4) After drying the separated layers, put them together with the complete paper sample into a constant temperature and humidity laboratory [(23±1)℃, (50±2)%] for more than 24h for standby;

[0069] (5) Measure the mass of each layer with an analytical balance;

[0070] (6) Calculate the surface / core layer weight ratio according to the formula.

[0071] Repeat the test 5 times, take the average value, and calculate the surface / core layer weight ratio in this example to be 0.5.

[0072] Comparative Example 2:

[0073] A method for preventing yellowing of white cardboard for cigarettes by controlling the surface / core layer weight ratio of white cardboard for cigarettes, and a method for detecting the surface / core layer weight ratio of white cardboard for cigarettes, comprising the following steps:

[0074] (1) Soak the paper sample in water for 48 hours or more, with water temperature being 25°C;

[0075] (2) After taking out, use water-absorbing paper to dry the excess water;

[0076] (3) Use tweezers to separate the surface, core and bottom layers, and the separation process should be slow and forceful in the same direction to ensure that the fibers of each layer are completely separated and not adhered to each other;

[0077] (4) Dry the separated layers of paper samples and place them together with the intact paper sample in a constant temperature and humidity laboratory [(23±1)℃, (50±2)%] for 24 hours or more for standby;

[0078] (5) Measure the mass of each layer using an analytical balance;

[0079] (6) Calculate the surface / core layer weight ratio according to the formula.

[0080] Repeat the test 5 times, take the average value, and calculate the surface / core layer weight ratio in this example to be 0.55.

[0081] The paper samples involved in Examples 1-3 and the paper samples involved in Comparative Examples 1 and 2 were subjected to light resistance treatment, and the light resistance treatment experiment was carried out using a SUNTEST XLS+ table type xenon lamp aging tester. The experimental conditions were as follows: the filter (simulated light source) was selected to simulate outdoor light conditions (daylight); the value of irradiation intensity was set to 750 W / m 2 ; the irradiation wavelength range was 300-800 nm; the temperature sensor was BST (black mark thermometer), the BST temperature was 40°C, and the temperature control range was not more than 45°C; the exposure time was 48 hours; the CIEL*a*b values of the paper before and after aging were measured to obtain the light resistance ΔE ab value, and the specific data are shown in Table 1:

[0082] Table 1 Light resistance ΔE ab value obtained by experiment

[0083] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Delta E ab ]] 4 3 2 7 6

[0084] As can be seen from Table 1, there is a clear correlation between the grammage ratio of the surface core layer and the lightfastness value, the greater the grammage ratio of the surface core layer, the lower the lightfastness value of the paper, which means that the paper has a smaller yellowing value and a lower possibility of yellowing. Therefore, the method for preventing the yellowing of the white cigarette card paper in the embodiment is feasible, which can prevent the yellowing of the white cigarette card paper by controlling the grammage ratio of the surface core layer of the white cigarette card paper.

[0085] The above description of disclosed embodiments enables those skilled in the art to carry out or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preventing white cardboard for cigarettes from yellowing, characterized in that, Without relying on the addition of fluorescent whitening agents or yellowing inhibitors, yellowing of cigarette white cardboard is prevented by controlling the basis weight ratio of the surface and core layers; the basis weight ratio of the surface and core layers ranges from 0.9 to 1.1; the surface layer of the cigarette white cardboard is made of sulfate wood pulp, and the core layer of the cigarette white cardboard is made of chemimechanical pulp with a lignin content of not less than 80%.

2. The method for preventing yellowing of cigarette white cardboard according to claim 1, characterized in that, The white cardboard used for cigarettes is the base paper for cigarette packs and box packaging printing.

3. A method for detecting the basis weight ratio of the surface and core layers of cigarette white cardboard, used to implement or verify the method for preventing yellowing of cigarette white cardboard as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. Soak the paper sample of cigarette white cardboard in a solvent at a certain temperature for a certain time, and then take it out. The treatment temperature is 20-30℃ and the soaking time is 48-72h. S2. Separate the paper pattern into three layers: face, core, and bottom. S3. After drying the separated paper samples, place them together with the intact paper sample in a constant temperature and humidity environment until the quality is constant. S4. Weigh the mass of each layer of the paper sample and the mass of the complete paper sample, and calculate the core layer weight ratio.

4. The method for detecting the basis weight ratio of the surface and core layers of cigarette white cardboard according to claim 3, characterized in that, The solvent used in step S1 is water.

5. The method for detecting the basis weight ratio of the surface and core layers of cigarette white cardboard according to claim 3, characterized in that, The separation process in step S2 should be carried out slowly in the same direction to ensure that the fibers of each layer are separated as completely as possible without sticking together.

6. The method for detecting the basis weight ratio of the surface and core layers of cigarette white cardboard according to claim 3, characterized in that, The constant temperature and humidity environment in step S3 is 23±1℃ and 50±2%.

7. The method for detecting the basis weight ratio of the surface and core layers of cigarette white cardboard according to claim 3, characterized in that, In step S4, the formula for calculating the weight ratio of the top and bottom layers is (top layer + bottom layer) ÷ core layer × 100%.