CN116694152A - Humidity-regulating coating, preparation method thereof and application thereof in cigarette case - Google Patents

Abstract

The invention discloses a humidity-regulating coating, a preparation method thereof and an application in cigarette boxes. After mixing diatomite with polyacrylic acid solution and polyvinyl alcohol solution evenly, shear emulsification to obtain an emulsion, add an inorganic acid catalyst to the emulsion to catalyze the esterification reaction, and mix evenly with calcium chloride solution to obtain humidity control coating. The humidity-adjusting coating has the function of adjusting the humidity of the environment. It can absorb moisture in the air in a humid environment, and can release its own moisture in a dry environment, thereby playing a buffer role and keeping the environment in a more suitable and more comfortable environment. Stable humidity, which is applied to the cigarette box, makes the environment inside the cigarette box maintain a relatively stable and suitable humidity for a long time.

Description

A kind of humidity control coating and its preparation method and its application in cigarette case

technical field

The invention relates to a humidity-adjusting coating, in particular to a humidity-adjusting coating which can absorb moisture in the air in a humid environment and release its own moisture in a dry environment, and also relates to a preparation method and a moisture-conditioning coating for the humidity-adjusting coating. The application of the wet paint in the cigarette box belongs to the technical field of cigarettes.

Background technique

After the cigarette box is unsealed, its barrier system is destroyed, and the cigarettes in the box will be affected by the external environment. When the external environment is too humid, the cut tobacco will be damp, the smoke will be dull and opaque, and the aroma will decrease; when the external environment is too dry, the cut tobacco will lose water, the smoke will be dry, strong irritation, and poor comfort. In order to enable consumers to maintain a good taste from the first cigarette to the last cigarette, it is necessary for the cigarette case to still have a certain moisture-proof and moisturizing ability after opening. This requires the addition of materials with a humidity-regulating effect inside the cigarette case. Compared with putting humidity-regulating materials inside the cigarette case, coating the humidity-regulating paint on the inner surface of the cigarette case in advance is more conducive to simplifying the wrapping process.

Contents of the invention

In view of the above-mentioned technical problems existing in the prior art, the first object of the present invention is to provide a kind of humidity-regulating paint, which has the effect of regulating the humidity of the environment, and can absorb moisture in the air in a humid environment, while In a dry environment, it can release its own moisture, thus acting as a buffer, so that the environment is at a more suitable and stable humidity.

The second object of the present invention is to provide a method for preparing a humidity-adjusting paint, which is simple to operate, mild in reaction conditions, low in raw material cost, and conducive to large-scale production.

The third object of the present invention is to provide an application of a humidity-regulating paint, which is coated inside the cigarette case, and when the cigarette case is opened, it can absorb moisture in the air in a humid environment, and can absorb moisture in the air in a dry environment. It releases its own moisture, thereby playing a buffer role, so that the environment inside the cigarette box can maintain a relatively stable and suitable humidity for a long time, which solves the problem that when the external environment is too humid, the shredded tobacco will be damp. The smoke is dull and opaque, the aroma is reduced, and when the external environment is too dry, the shredded tobacco will lose water, the smoke is dry, strong irritation, and poor comfort, which greatly reduces the impact of the environment on the quality of the cigarette after the cigarette pack is opened. Influence.

In order to achieve the above-mentioned technical purpose, the invention provides a kind of preparation method of moisture-conditioning coating, it comprises the following steps:

1) After mixing diatomite with polyacrylic acid solution and polyvinyl alcohol solution evenly, adding an emulsifier for shear emulsification to obtain an emulsion;

2) adding an inorganic acid catalyst into the emulsion to catalyze the esterification reaction to obtain an emulsion containing a reticulated PVA/PAA/diatomaceous earth compound;

3) The calcium chloride solution is uniformly mixed with the emulsion containing the reticular PVA/PAA/diatomaceous earth compound to obtain the product.

The technical solution of the present invention first shears and emulsifies diatomite with polyacrylic acid and polyvinyl alcohol. Polyacrylic acid and polyvinyl alcohol have good hydrophilicity, can fully stretch their polymer chains in aqueous solution, and can play a role in dispersion at the same time. Diatomaceous earth is evenly dispersed in the solution system, so that a uniform emulsion can be obtained through shear emulsification, and then an acid catalyst is added to catalyze the esterification reaction, so that the esterification reaction between the uniformly dispersed polyacrylic acid and polyvinyl alcohol forms an interpenetration The polymer network, while the diatomite is uniformly dispersed in the polymer grid to form a network PVA/PAA/diatomite composite, and finally the calcium chloride is loaded on the polymer network by physical and chemical synergistic adsorption through liquid phase mixing. On the reticular PVA/PAA/diatomite composite, a moisture-regulating coating composed of polyacrylic acid and polyvinyl alcohol crosslinked polymer network, calcium chloride inorganic salt and diatomite mineral compound is formed. In the humidity-adjusting coating of the technical solution of the present invention, diatomite is dispersed in the polymer grid to play a supporting role, and fully utilizes its own rich pore structure to endow the coating layer with a well-developed pore structure. At the same time, in the inorganic mineral The combination with the polymer network can also form some fine pores. These pore structures form a good water vapor channel, increase the effective contact area between the polymer inside the coating layer and the environment, and can better absorb water vapor. Introduced into the material, it is also conducive to the release of internal water vapor. The acrylic acid and polyvinyl alcohol cross-linked polymer network contains a large number of carboxyl and hydroxyl groups, which makes the coating layer exhibit higher moisture absorption capacity and moisturizing properties. , and calcium chloride is easy to deliquescence, which has good water absorption performance, but its moisture absorption is easy to lose, and diatomite and polymer network can store calcium chloride, so that it is not easy to lose after moisture absorption and deliquescence.

As a preferred solution, the mass ratio of the diatomite to the polyacrylic acid solution and the polyvinyl alcohol solution is 5-8:5-8:105-115; the mass percent concentration of the polyacrylic acid solution is 25-35% ; The mass percent concentration of the polyvinyl alcohol solution is 20-40%.

As a preferred solution, the polyvinyl alcohol in the polyvinyl alcohol solution is composed of 1788 type polyvinyl alcohol and 0588 type polyvinyl alcohol in a mass ratio of 10-15:15-20. In the humidity-controlling paint of the present invention, two polyvinyl alcohols with different molecular weights and degrees of alcoholysis are used in combination. If only 0588 type polyvinyl alcohol is used, although the humidity-controlling effect is good, after the calcium chloride absorbs moisture, the composite material The free water in the medium increases, because the molecular weight of the 0588 type polyvinyl alcohol itself is low, the polymer molecular chain is easy to move, resulting in the stickiness of the material, and by introducing an appropriate proportion of the 1788 type polyvinyl alcohol to participate in the reaction, on the one hand it can Increasing the molecular weight of the polymer, on the other hand, can prepare molecular chains of different lengths, so that they can be better entangled and not easy to move.

As a preferred solution, the mass ratio of the emulsifier to diatomaceous earth is 1-2:5-8.

As a preferred solution, the emulsifier is Tween 80.

As a preferred solution, the temperature of the esterification reaction is 85-100° C., and the time is 3-4 hours.

As a preferred solution, the mass percent concentration of the calcium chloride solution is 40%-50%. An appropriate proportion of calcium chloride is introduced into the humidity-adjusting coating of the present invention, and the calcium chloride mainly plays the role of rapid water absorption. After the cigarette case is opened, a faster humidity-conditioning rate is required. Calcium chloride can greatly increase the moisture absorption rate of the material. In a humid environment, it can absorb moisture in the air and reduce the relative humidity of the environment. Part of the absorbed moisture forms crystalline hydrate with itself, and part of it exists in a free state. In the pores of the coating, in a dry environment, the free moisture in the coating can be released into the air, increasing the relative humidity of the environment.

As a preferred solution, the mass ratio of calcium chloride to diatomaceous earth in the calcium chloride solution is 10-15:5-8.

The inorganic acid catalysts involved in the present invention are common inorganic acids such as hydrochloric acid.

The invention provides a humidity-adjusting paint obtained by the preparation method.

The main component of the humidity-controlling coating of the present invention is PVA/PAA/diatomite/calcium chloride compound, wherein, the interpenetrating cross-linked polymer network formed by the chain-like PVA and PAA after the esterification reaction, the interpenetrating cross-linked polymer network The cross-linked polymer network reduces the regularity inside the coating layer, and at the same time, due to the presence of a large number of carboxyl and hydroxyl groups on the cross-linked polymer network, it increases the hygroscopic capacity and has good moisturizing properties. Diatomaceous earth It has a porous structure and has good physical adsorption and loading functions. It makes full use of its own developed pore structure to endow the coating with developed pores. At the same time, the junction between the inorganic mineral and the polymer network is also Some fine pores can be formed. These pores increase the effective contact area between the polymer and the environment, which can better introduce water vapor into the material, and are also conducive to the emission of internally absorbed water vapor, which can achieve better humidity control. As a result, calcium chloride has good hygroscopic performance, can be stored in the polymer network and inorganic mineral pore structure, and is not easy to lose after moisture absorption and deliquescence.

The invention also provides an application of the humidity-regulating paint, which is applied to cigarette boxes.

As a preferred solution, it is coated on the inner side of the cigarette pack.

Humidity-adjusting paint provided by the invention adopts the following specific steps:

1) According to the mass fraction, take 10-15 parts of 1788 type polyvinyl alcohol (PVA), 15-20 parts of 0588 type polyvinyl alcohol, 80 parts of deionized water, heat to 95 ° C, mechanically stir until the polyvinyl alcohol is completely dissolved, Obtain polyvinyl alcohol solution;

2) Take 5-8 parts of 200-mesh diatomite and 5-8 parts of 30% polyacrylic acid (PAA) solution, add them to the dissolved polyvinyl alcohol solution, and stir them evenly to obtain a PVA/PAA/diatomite mixture ;

3) Take 1 to 2 parts of Tween 80, dissolve it in 5 parts of deionized water as emulsification, add the emulsifier to the mixture in the previous step, increase the mechanical stirring speed, and make it emulsify under the action of high shear force for 10 ~20min, PVA/PAA/diatomaceous earth emulsion is obtained after emulsification;

4) Add a small amount of hydrochloric acid, heat to 85-100°C, make the hydroxyl group on PVA and the carboxyl group on PAA carry out esterification reaction, continue mechanical stirring for 3-4 hours, so as to obtain the network structure PVA/PAA/diatomite emulsion;

5) Take 10 to 15 parts of calcium chloride and dissolve in 15 parts of deionized water to obtain a calcium chloride solution, add the calcium chloride solution to the PVA/PAA/diatomite emulsion with a network structure, and continue to stir mechanically for 1 hour , make it fully mixed, and finally get PVA/PAA/diatomaceous earth/calcium chloride coating with humidity control effect.

Compared with the current technology, the beneficial technical effect brought by the technical solution of the present invention:

1) The humidity-adjusting coating of the present invention has the effect of better adjusting the humidity of the environment. It can absorb the moisture in the air in a humid environment, and can release its own moisture in a dry environment, thereby playing a buffering role and making the environment in a dry environment. A more suitable humidity. The moisture-conditioning coating is formed by the cross-linking of PVA and PAA to form an interpenetrating polymer network as a matrix polymer. The interpenetrating polymer network reduces the regularity inside the humidity-conditioning coating. The existence of two kinds of hydrophilic groups of hydroxyl groups improves the moisture absorption capacity and high moisture retention performance of the humidity-conditioning coating. The structure is brought into the interior of the composite material. At the same time, some fine pores can also be formed at the junction between the diatomite and the polymer to increase the contact area between the polymer and the environment, so that these pores can better absorb water vapor. The introduction of the humidity-conditioning coating inside is also conducive to the volatilization of internal moisture and achieves a better humidity-conditioning effect. Calcium chloride is an inorganic salt with good hygroscopicity, which can be stored in the grid of the interpenetrating polymer network and diatomaceous earth In the pore structure, it is not easy to lose after moisture absorption and deliquescence.

2) The moisture-regulating coating of the present invention has a high solid content, and after one coating and drying, more moisture-regulating coating can be kept on the unit area of cigarette packaging cardboard, making the subsequent use process more convenient.

3) The humidity-adjusting coating of the present invention has good stability and ensures no sedimentation for a long time.

4) The preparation method of the humidity-adjusting coating of the present invention has simple operation, mild reaction conditions, low cost of raw materials, and is favorable for large-scale production.

5) The moisture-regulating coating of the present invention is coated inside the cigarette case. After the cigarette case is opened, it can absorb moisture in the air in a humid environment, and can release its own moisture in a dry environment, thereby playing a buffering role and making the cigarette case The internal environment is at a relatively suitable humidity, which solves the problem that when the external environment is too humid, the shredded tobacco will be damp, the smoke will be dull and opaque, and the aroma will decrease, and when the external environment is too dry, the shredded tobacco will lose water. , Dry smoke, strong irritation, poor comfort and other defects, greatly reducing the impact of the environment on the quality of cigarettes after the cigarette pack is opened.

Description of drawings

Fig. 1 is the variation of moisture content of shredded tobacco with time under different humidity environments of the humidity-controlling coating of Example 1.

Figure 2 is a comparison of the hygroscopic performance and moisture releasing performance of different humidity-adjusting coatings in Comparative Example 1.

Detailed ways

The following examples are intended to further illustrate the content of the present invention, but not to limit the protection scope of the claims.

Example 1

A) According to the mass fraction, take 10 parts of 1788 type polyvinyl alcohol (PVA), 20 parts of 0588 type polyvinyl alcohol, and 80 parts of deionized water, heat to 95 ° C, and mechanically stir until the polyvinyl alcohol is completely dissolved to obtain polyvinyl alcohol solution;

B) Take 6 parts of 200-mesh diatomite and 6 parts of 30% polyacrylic acid (PAA) solution, add them to the dissolved polyvinyl alcohol solution, and stir them evenly to obtain a PVA/PAA/diatomite mixture;

C) Take 1 part of Tween 80, dissolve it in 5 parts of deionized water as emulsification, add the emulsifier to the mixture in the previous step, increase the mechanical stirring speed, make it emulsify under the action of high shear force for 15 minutes, emulsify Obtain PVA/PAA/diatomite emulsion after finishing;

D) adding a small amount of hydrochloric acid, heating to 95° C., so that the hydroxyl groups on the PVA and the carboxyl groups on the PAA undergo an esterification reaction, and continue to mechanically stir for 3 hours, thereby obtaining a PVA/PAA/diatomite emulsion with a network structure;

E) Get 15 parts of calcium chloride, be dissolved in 15 parts of deionized water, obtain calcium chloride solution, add calcium chloride solution in the PVA/PAA/diatomite emulsion of network structure, continue mechanical stirring 1h, make It is fully mixed to finally obtain a PVA/PAA/diatomaceous earth/calcium chloride coating with a humidity-regulating effect.

Example 2

A) According to the mass fraction, take 15 parts of 1788 type polyvinyl alcohol (PVA), 15 parts of 0588 type polyvinyl alcohol, and 80 parts of deionized water, heat to 95 ° C, and mechanically stir until the polyvinyl alcohol is completely dissolved to obtain polyvinyl alcohol solution;

B) Take 5 parts of 200-mesh diatomite and 8 parts of 30% polyacrylic acid (PAA) solution, add them to the dissolved polyvinyl alcohol solution, and stir them evenly to obtain a PVA/PAA/diatomite mixture;

C) Take 1 part of Tween 80, dissolve it in 5 parts of deionized water as emulsification, add the emulsifier to the mixture in the previous step, increase the mechanical stirring speed, make it emulsify under the action of high shear force for 10 minutes, and emulsify Obtain PVA/PAA/diatomite emulsion after finishing;

D) adding a small amount of hydrochloric acid, heating to 95° C., so that the hydroxyl groups on the PVA and the carboxyl groups on the PAA undergo an esterification reaction, and continue to mechanically stir for 3.5 hours, thereby obtaining a PVA/PAA/diatomite emulsion with a network structure;

E) Get 10 parts of calcium chloride, be dissolved in 15 parts of deionized water, obtain calcium chloride solution, add calcium chloride solution in the PVA/PAA/diatomite emulsion of network structure, continue mechanical stirring 1h, make It is fully mixed to finally obtain a PVA/PAA/diatomaceous earth/calcium chloride coating with a humidity-regulating effect.

Example 3

A) According to the mass fraction, take 20 parts of 1788 type polyvinyl alcohol (PVA), 10 parts of 0588 type polyvinyl alcohol, and 80 parts of deionized water, heat to 95 ° C, and mechanically stir until the polyvinyl alcohol is completely dissolved to obtain polyvinyl alcohol solution;

B) Take 8 parts of 200-mesh diatomite and 5 parts of 30% polyacrylic acid (PAA) solution, add them to the dissolved polyvinyl alcohol solution, and stir them evenly to obtain a PVA/PAA/diatomite mixture;

C) Take 2 parts of Tween 80, dissolve it in 5 parts of deionized water as emulsification, add the emulsifier to the mixture in the previous step, increase the mechanical stirring speed, make it emulsify under the action of high shear force for 20min, emulsify Obtain PVA/PAA/diatomite emulsion after finishing;

D) adding a small amount of hydrochloric acid, heating to 95° C., so that the hydroxyl groups on the PVA and the carboxyl groups on the PAA undergo an esterification reaction, and continue to mechanically stir for 4 hours, thereby obtaining a PVA/PAA/diatomite emulsion with a network structure;

E) get 12 parts of calcium chloride, be dissolved in 15 parts of deionized water, obtain calcium chloride solution, add calcium chloride solution in the PVA/PAA/diatomite emulsion of network structure, continue mechanical stirring 1h, make It is fully mixed to finally obtain a PVA/PAA/diatomaceous earth/calcium chloride coating with a humidity-regulating effect.

The moisture-regulating coating prepared in Examples 1-3 is coated on the inside of the cigarette box trademark paper, so that the cigarette package has a humidity-regulating effect. After opening the cigarette pack, place it in a constant temperature and humidity box at 22°C, 30% and 22°C, 80%, take a certain number of cigarettes at a certain time interval, take 20 cigarettes within 24 hours, and test the moisture content of the shredded tobacco , while doing a blank control. The humidity-controlling effects of the humidity-controlling coatings in Examples 1-3 are similar, and the humidity-controlling effect in Example 1 is used as an example to illustrate. The specific test results are shown in Figure 1. No matter in a dry or humid environment, there are The changes in moisture content of shredded tobacco in the cigarette packs were smaller than those in the blank control sample, which indicated that the humidity-regulating material played a certain humidity-regulating effect after the cigarette pack was opened.

Comparative Example 1

Adopt the same method as Example 1 to prepare three kinds of humidity-adjusting coatings as contrast: 1) PVA/PAA/calcium chloride coating without diatomite, 2) PVA/PAA/diatomite coating without calcium chloride, 3) Prepare PVA/diatomaceous earth/calcium chloride coatings by physical blending, and place these three coatings and PVA/PAA/diatomite/calcium chloride coatings in a constant temperature and humidity box for moisture absorption and desorption Performance test, the test method is: (a) Moisture absorption performance: place the sample in a constant temperature and humidity box at 22°C, 60% RH, balance to constant weight, and then adjust the constant temperature and humidity box to 22°C, 80% RH, Use the method of "comb in the front and comb in the back" to measure the quality change data with time within 48 hours, and draw the moisture absorption curve. (b) Humidity release performance: place the sample in a constant temperature and humidity box at 22°C and 60% RH, balance it to constant weight, then adjust the constant temperature and humidity box to 22°C and 30% RH, and use "front dense comb "Measure the quality change data with time within 48h, and draw the dehumidification curve. The test results are shown in Figure 2. The addition of PVA improves the moisture absorption capacity of the material, the addition of diatomaceous earth improves the moisture release capacity of the material, and the addition of calcium chloride has a greater effect on the moisture absorption and release performance of the humidity control material. improve.

Claims (11)

1. a preparation method for humidity-adjusting coating, is characterized in that: comprise the following steps: 1) After mixing diatomite with polyacrylic acid solution and polyvinyl alcohol solution evenly, adding an emulsifier for shear emulsification to obtain an emulsion; 2) adding an inorganic acid catalyst into the emulsion to catalyze the esterification reaction to obtain an emulsion containing a reticulated PVA/PAA/diatomaceous earth compound; 3) The calcium chloride solution is uniformly mixed with the emulsion containing the reticular PVA/PAA/diatomaceous earth compound to obtain the product. 2. the preparation method of a kind of humidity-conditioning coating according to claim 1, is characterized in that: The mass ratio of the diatomite to the polyacrylic acid solution and the polyvinyl alcohol solution is 5～8:5～8:105～115; The mass percent concentration of the polyacrylic acid solution is 25% to 35%; The mass percent concentration of the polyvinyl alcohol solution is 20-40%. 3. the preparation method of a kind of humidity-conditioning coating according to claim 2, is characterized in that: The polyvinyl alcohol in the polyvinyl alcohol solution is composed of 1788 type polyvinyl alcohol and 0588 type polyvinyl alcohol according to the mass ratio of 10-15:15-20. 4. The method for preparing a humidity-adjusting paint according to claim 1, characterized in that: the mass ratio of the emulsifier to diatomaceous earth is 1-2:5-8. 5. The preparation method of a humidity-adjusting paint according to claim 1 or 4, characterized in that: the emulsifier is Tween 80. 6 . The method for preparing a humidity-adjusting paint according to claim 1 or 4, characterized in that: the temperature of the esterification reaction is 85-100° C., and the time is 3-4 hours. 7. The method for preparing a humidity-adjusting paint according to claim 1, characterized in that: the mass percent concentration of the calcium chloride solution is 40%-50%. 8 . The method for preparing a humidity-adjusting paint according to claim 1 , wherein the mass ratio of calcium chloride to diatomite in the calcium chloride solution is 10-15:5-8. 9. A humidity-adjusting coating, characterized in that it is obtained by the preparation method described in any one of claims 1-8. 10. The application of a humidity-regulating coating according to claim 9, characterized in that it is applied to cigarette boxes. 11. The application of a humidity-adjusting coating according to claim 10, characterized in that: it is coated on the inner side of the cigarette case.