A water-based glue for cigarettes and its preparation process

Abstract

The present invention discloses a water-based adhesive for cigarettes and its preparation process, belonging to the technical field of the preparation of special adhesives. The water-based adhesive for cigarettes comprises the following components: acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, additives and deionized water; wherein, the starch-based component is prepared by taking starch as a raw material, dehydrating and pre-gelatinizing it through vacuum heat treatment, then mixing it with polyvinyl alcohol, and carrying out an esterification reaction with acrylic acid and rosin acid under the alkaline condition of sodium hydroxide. Through the modification of composite components, the present invention prepares a water-based adhesive for cigarettes with high bonding strength, good initial adhesion performance, fast drying and stable emulsion. On the basis of the existing EVA emulsion, the present invention compositely uses an acrylate emulsion and a modified starch component, which promotes emulsification and improves the cross-linking and curing speed at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of special adhesives, and particularly relates to a water-based cigarette glue and a preparation process thereof. Background Technique

[0002] Water-based cigarette glue is an adhesive used in the tobacco industry and belongs to one of the tobacco materials. It uses water as the dispersion medium and has the characteristics of environmental protection, non-toxicity, and non-flammability. It is mainly used in links such as tobacco leaf processing, cut tobacco finishing, and cigarette production, including the adhesion at the cigarette lap joint, cigarette mouthpiece joint, filter rod center line, and carton and small box packaging, to improve the quality and production efficiency of tobacco products. Tobacco materials are the basis of cigarette manufacturing and to a certain extent determine the quality, grade, and value of cigarette products, and are an important link in the cigarette quality chain. In recent years, with the technological improvement of many domestic cigarette factories and the introduction of high-speed cigarette machine equipment, the cigarette production speed has increased from the original 1000 cigarettes / min to the single machine speed of 10000 cigarettes / min, which has led to an increasing demand for cigarette glue and higher requirements for its quality and performance. Since during the operation of the high-speed cigarette machine, the running speed of the cigarette paper is extremely high (about 600 - 700 m / min), higher requirements are put forward for the performance of water-based cigarette glue.

[0003] Ethylene-vinyl acetate copolymer emulsion (i.e., EVA emulsion) is currently one of the most important raw materials for water-based cigarette glue. Although the existing EVA emulsion-based glue has excellent overall performance, there are still problems such as poor initial tack, low bonding strength, slow drying speed, and the need to improve the emulsion stability. Starch-based glue also has poor bonding force and stability and is difficult to meet the requirements of high-speed machinery and is thus eliminated in the initial stage. Summary of the Invention

[0004] In view of the above problems, the present invention provides a water-based cigarette glue and a preparation process thereof.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A water-based cigarette glue, comprising the following components:

[0007] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, auxiliary agent, and deionized water;

[0008] Among them, the preparation method of the starch-based component comprises the following steps:

[0009] The starch is subjected to vacuum heat treatment at 80 - 100 °C, and then formulated into a dispersion with a mass concentration of 10 - 40%. After adding polyvinyl alcohol, the pH is adjusted to alkaline. At 30 - 60 °C, a mixed solution of sodium acrylate, rosin and sodium hydroxide is slowly added while stirring. After the addition is completed, the mixture is kept warm and stirred for 1 - 3 h. After the reaction is completed, it is cooled, ethanol is added to dilute the reaction system, the precipitate is separated, washed to neutrality, and dried to obtain the starch-based product.

[0010] In some preferred embodiments, the solid content of the water-based adhesive for cigarettes is 45 - 50 wt%.

[0011] In some preferred embodiments, the mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component, and the additive is 10:(8 - 12):(1.4 - 3.0):(0.1 - 0.5).

[0012] In some preferred embodiments, the average molecular weight of the polyvinyl alcohol is 16,000 - 20,000, and the mass ratio of the starch, the polyvinyl alcohol, the sodium acrylate, the rosin and the sodium hydroxide is 10:(1 - 1.8):(8 - 14):(2 - 3.8):(3 - 5).

[0013] In some preferred embodiments, the additive is one or more of a defoaming agent, a thickening agent, and a preservative. Among them, the defoaming agent is polydimethylsiloxane, the thickening agent is carboxymethyl cellulose or methylated composite modified carboxymethyl cellulose, or its sodium salt or potassium salt; the preservative is isothiazolone.

[0014] In some preferred embodiments, the solid content of the acrylic resin emulsion is 45 - 55 wt%, the pH is 7 - 9, the viscosity is 300 - 1000 mPa·s, and the average particle size is 150 - 250 nm.

[0015] In some preferred embodiments, the acrylic resin emulsion is composed of an acrylic resin monomer, an emulsifier, an initiator, a buffer, a stabilizer and deionized water. The emulsifier is 1 - 3 wt% of the total mass of the monomers, the initiator is 0.1 - 1 wt% of the total mass of the monomers, the buffer is 0.1 - 0.5 wt% of the total mass of the monomers, and the stabilizer is 0.1 - 0.5 wt% of the total mass of the monomers.

[0016] In some preferred embodiments, the acrylic resin monomer is composed of methyl methacrylate, butyl acrylate and methacrylic acid, and their mass ratio is 10:(9 - 12):(1 - 3).

[0017] In some preferred embodiments, the emulsifier in the acrylic resin emulsion includes a main emulsifier and a co-emulsifier. The main emulsifier is sodium dodecyl sulfate; the co-emulsifier is nonylphenol polyoxyethylene ether; the mass ratio of the main emulsifier to the co-emulsifier is (4 - 5):1.

[0018] In some preferred embodiments, the initiator in the acrylic resin emulsion is ammonium persulfate, potassium persulfate or sodium persulfate; the buffer is sodium bicarbonate, sodium dihydrogen phosphate or sodium acetate; the stabilizer is sodium carboxymethyl cellulose.

[0019] In some preferred embodiments, the solid content of the ethylene-vinyl acetate copolymer emulsion is 50 - 75 wt%, the viscosity is 500 - 5000 mPa·s, and the average particle size is 100 - 1000 nm.

[0020] In some preferred embodiments, the ethylene-vinyl acetate copolymer emulsion is composed of monomers, an emulsifier, an oxidant, a reductant and deionized water. The emulsifier is 2 - 7 wt% of the total mass of the monomers, the oxidant is 0.5 - 1 wt% of the total mass of the monomers, and the reductant is 0.1 - 0.5 wt% of the total mass of the monomers.

[0021] In some preferred embodiments, the monomers in the ethylene-vinyl acetate copolymer emulsion are composed of vinyl acetate, ethylene and butyl acrylate, and their mass ratio is 100:(10 - 20):(1 - 4).

[0022] In some preferred embodiments, the emulsifier in the ethylene-vinyl acetate copolymer emulsion includes octadecyl trimethyl ammonium bromide and polyvinyl alcohol, and their mass ratio is 1:(1 - 2).

[0023] In some preferred embodiments, the oxidant in the ethylene-vinyl acetate copolymer emulsion is tert-butyl hydroperoxide, and the reductant is sodium metabisulfite.

[0024] Another object of the present invention is to provide a preparation method of the aforementioned water-based cigarette glue, comprising the following steps:

[0025] Under the condition of 50 - 70 °C, mix the acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion, stir well to obtain a mixed emulsion, add the starch-based component, keep warm and stir for 0.5 - 2 h, add the additives and mix, and finally adjust the solid content with deionized water, and then filter and discharge to obtain the product.

[0026] The beneficial effects of the present invention are:

[0027] Aiming at the problems in the prior art that the initial tack of the water-based glue for cigarettes based on EVA is poor, the bonding strength is low, the drying speed is slow, and the emulsion stability is weak, the present invention prepares a water-based glue for cigarettes with high bonding strength, good initial tack performance, fast drying, and stable emulsion through composite component modification. The present invention has good applicability on the machine. Based on the existing EVA emulsion, the present invention compositely adds acrylate emulsion and modified starch components, which improves the cross-linking and curing speed while promoting emulsification. Specifically, the present invention uses starch as a raw material, pre-gelatinizes it by vacuum heat treatment and dehydration, then mixes it with polyvinyl alcohol, and conducts an esterification reaction with acrylic acid and rosin acid under the alkaline condition of sodium hydroxide, grafting active alkenyl groups and hydrophobic diterpene rosin groups on the hydroxyl groups of starch and polyvinyl alcohol. On the one hand, the active alkenyl groups can participate in the curing of the water-based glue, improving the cross-linking and curing speed and strength. The polyvinyl alcohol groups can protect and stabilize polymer particles, preventing them from aggregating and precipitating, and at the same time forming an amphiphilic structure with the hydrophobic diterpene rosin groups, effectively promoting system emulsification and improving stability. Specific Embodiments

[0028] The present invention will be further described in conjunction with the following embodiments. Example 1

[0029] A water-based glue for cigarettes, comprising the following components:

[0030] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, preservative, and deionized water; wherein, the mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component, and the preservative is 10:10.9:2.4:0.15;

[0031] The acrylic resin emulsion is composed of acrylic resin monomers, emulsifiers, initiators, buffers, stabilizers, and deionized water. The acrylic resin monomers are composed of methyl methacrylate, butyl acrylate, and methacrylic acid, and their mass ratio is 10:10:1.8; the emulsifiers include a main emulsifier and a co-emulsifier. The main emulsifier is sodium dodecyl sulfate, and the co-emulsifier is nonylphenol polyoxyethylene ether. The mass ratio of the main emulsifier to the co-emulsifier is 4.5:1, and the emulsifier is 1.9 wt% of the total mass of the monomers; the initiator is ammonium persulfate, and the initiator is 0.4 wt% of the total mass of the monomers; the buffer is sodium dihydrogen phosphate, and the buffer is 0.4 wt% of the total mass of the monomers; the stabilizer is sodium carboxymethyl cellulose, and the stabilizer is 0.3 wt% of the total mass of the monomers; the solid content of the acrylic resin emulsion is 49 wt%, the pH is 8.0, the viscosity is 660 mPa·s, and the average particle size is 215 nm;

[0032] The ethylene-vinyl acetate copolymer emulsion is composed of monomers, emulsifiers, oxidants, reducing agents and deionized water, wherein the monomers are composed of vinyl acetate, ethylene and butyl acrylate, and the mass ratio thereof is 100:17:2.4; the emulsifier is composed of octadecyltrimethylammonium bromide and polyvinyl alcohol, and the mass ratio thereof is 1:1.7, and the emulsifier is 4.5wt% of the total mass of the monomers; the oxidant is tert-butyl hydroperoxide, and the reducing agent is sodium pyrosulfite, and the oxidant is 0.7wt% of the total mass of the monomers, and the reducing agent is 0.4wt% of the total mass of the monomers; the solid content of the ethylene-vinyl acetate copolymer emulsion is 65wt%, the viscosity is 3500mPa·s, and the average particle size is 520nm;

[0033] The preparation method of the starch-based component comprises the following steps:

[0034] The starch is placed at 90°C for vacuum heat treatment to constant weight, and then prepared into a dispersion with a mass concentration of 20%, and the pH is adjusted to 8-10 after adding polyvinyl alcohol, and a mixed solution of sodium acrylate, rosin and sodium hydroxide is slowly added at 50°C while stirring, and the mixture is kept warm and stirred for 2 hours after the addition is completed. After the reaction is completed, the mixture is cooled, ethanol is added to dilute the reaction system, and the precipitate is separated and washed with ethanol solvent and deionized water to neutrality, and dried to obtain the starch-based product; wherein the average molecular weight of the polyvinyl alcohol is 16,000-20,000, and the mass ratio of the starch to the polyvinyl alcohol, the sodium acrylate, the rosin and the sodium hydroxide is 10:1.3:11.8:2.7:4.5;

[0035] The preservative is 1,2-benzisothiazol-3-one;

[0036] The preparation method of the water-based adhesive for cigarettes comprises the following steps:

[0037] At 65° C., the acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are mixed, and the mixed emulsion is fully stirred. The starch-based component is added, and the mixture is stirred for 1.5 hours at the same temperature. The preservative is added and mixed. Finally, the solid content is adjusted to 48wt% with deionized water, and the material is filtered (100 mesh) to obtain the product. Example 2

[0038] A water-based adhesive for cigarettes, comprising the following components:

[0039] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, preservative and deionized water; wherein the mass ratio of the solid content of the acrylic resin emulsion to the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component and the preservative is 10:10.9:2.4:0.15;

[0040] The acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are the same as those in Example 1;

[0041] The preparation method of the starch-based component comprises the following steps:

[0042] The starch is placed at 90°C for vacuum heat treatment until constant weight, and then formulated into a dispersion with a mass concentration of 20%. The pH is adjusted to 8-10. At 50°C, while stirring, a mixed solution of sodium acrylate, rosin, and sodium hydroxide is slowly added. After the addition is completed, the mixture is kept warm and stirred for reaction for 2 h. After the reaction is completed, it is cooled, ethanol is added to dilute the reaction system, the precipitate is separated, and it is washed with ethanol solvent and deionized water in turn until neutral, dried, and then mixed with polyvinyl alcohol to obtain the starch-based product; wherein, the average molecular weight of the polyvinyl alcohol is 16,000-20,000, and the mass ratio of the starch to the polyvinyl alcohol, the sodium acrylate, the rosin, and the sodium hydroxide is 10:1.3:11.8:2.7:4.5;

[0043] The preservative is 1,2-benzisothiazol-3-one;

[0044] The preparation method of the tobacco water-based glue is the same as that in Example 1. Example 3

[0045] A tobacco water-based glue, comprising the following components:

[0046] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, preservative, and deionized water; wherein, the mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component, and the preservative is 10:10.9:2.4:0.15;

[0047] The acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are the same as those in Example 1;

[0048] The preparation method of the starch-based component comprises the following steps:

[0049] The starch is placed at 90°C for vacuum heat treatment until constant weight for standby. Polyvinyl alcohol is added to deionized water, and then the pH is adjusted to 8-10. At 50°C, while stirring, a mixed solution of sodium acrylate, rosin, and sodium hydroxide is slowly added. After the addition is completed, the mixture is kept warm and stirred for reaction for 2 h. After the reaction is completed, it is cooled, ethanol is added to dilute the reaction system, the precipitate is separated, and it is washed with ethanol solvent and deionized water in turn until neutral, dried, and then mixed with the starch to obtain the starch-based product; wherein, the average molecular weight of the polyvinyl alcohol is 16,000-20,000, and the mass ratio of the starch to the polyvinyl alcohol, the sodium acrylate, the rosin, and the sodium hydroxide is 10:1.3:11.8:2.7:4.5;

[0050] The preservative is 1,2-benzisothiazol-3-one;

[0051] The preparation method of the water-based tobacco glue is the same as that in Example 1. Example 4

[0052] A water-based tobacco glue, comprising the following components:

[0053] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, preservative and deionized water; wherein, the mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component, and the preservative is 10:10.9:2.4:0.15;

[0054] The acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are the same as those in Example 1;

[0055] The preparation method of the starch-based component comprises the following steps:

[0056] Placing the starch under vacuum heat treatment at 90 °C until constant weight, then formulating it into a dispersion with a mass concentration of 20%, adding polyvinyl alcohol and then adjusting the pH to 8-10. At 50 °C, while stirring, slowly add the mixed solution of sodium acrylate and sodium hydroxide. After the addition is completed, continue to keep warm and stir for 2 h. After the reaction is completed, cool, add ethanol to dilute the reaction system, separate the precipitate, and wash it with ethanol solvent and deionized water in sequence until neutral, and then dry to obtain the starch-based product; wherein, the average molecular weight of the polyvinyl alcohol is 16,000-20,000, and the mass ratio of the starch, the polyvinyl alcohol, the sodium acrylate, and the sodium hydroxide is 10:1.3:11.8:4.5;

[0057] The preservative is 1,2-benzisothiazol-3-one;

[0058] The preparation method of the water-based tobacco glue is the same as that in Example 1. Example 5

[0059] A water-based tobacco glue, comprising the following components:

[0060] Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, preservative and deionized water; wherein, the mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, and the preservative is 10:10.9:0.15;

[0061] The acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are the same as those in Example 1;

[0062] The preservative is 1,2-benzisothiazol-3-one;

[0063] The preparation method of the water-based glue for cigarettes is the same as that in Example 1.

[0064]

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A water-based glue for cigarettes, characterized in that, Includes the following components: Acrylic resin emulsion, ethylene-vinyl acetate copolymer emulsion, starch-based component, additives and deionized water; Wherein, the preparation method of the starch-based component comprises the following steps: The starch is placed at 80-100° C. for vacuum heat treatment, and then prepared into a dispersion with a mass concentration of 10-40%, and after adding polyvinyl alcohol, the pH is adjusted to alkaline, and a mixed solution of sodium acrylate, rosin and sodium hydroxide is slowly added at 30-60° C. while stirring, and the mixture is kept warm and stirred for 1-3 hours after the addition is completed. After the reaction is completed, the mixture is cooled, ethanol is added to dilute the reaction system, and the precipitate is separated, washed to neutrality, and dried to obtain the starch-based product; The mass ratio of the solid content of the acrylic resin emulsion, the solid content of the ethylene-vinyl acetate copolymer emulsion, the starch-based component, and the auxiliary agent is 10: (8-12): (1.4-3.0): (0.1-0.5); The average molecular weight of the polyvinyl alcohol is between 16,000 and 20,000, and the mass ratio of the starch to the polyvinyl alcohol, the sodium acrylate, the rosin and the sodium hydroxide is 10: (1-1.8): (8-14): (2-3.8): (3-5).

2. The water-based adhesive for cigarettes according to claim 1, characterized in that, The acrylic resin emulsion has a solid content of 45-55wt%, a pH of 7-9, a viscosity of 300-1000mPa·s, and an average particle size of 150-250nm.

3. The water-based glue for cigarettes according to claim 1, wherein The acrylic resin emulsion is composed of acrylic resin monomer, emulsifier, initiator, buffer, stabilizer and deionized water, wherein the emulsifier accounts for 1-3wt% of the total weight of the monomer, the initiator accounts for 0.1-1wt% of the total weight of the monomer, the buffer accounts for 0.1-0.5wt% of the total weight of the monomer, and the stabilizer accounts for 0.1-0.5wt% of the total weight of the monomer.

4. The water-based adhesive for cigarettes according to claim 3, wherein The acrylic resin monomer is composed of methyl methacrylate, butyl acrylate and methacrylic acid, and the mass ratio thereof is 10:(9-12):(1-3).

5. The water-based adhesive for cigarettes according to claim 1, wherein, The ethylene-vinyl acetate copolymer emulsion has a solid content of 50-75wt%, a viscosity of 500-5000mPa·s, and an average particle size of 100-1000nm.

6. The water-based glue for cigarettes according to claim 1, wherein The ethylene-vinyl acetate copolymer emulsion is composed of monomers, emulsifiers, oxidants, reducing agents and deionized water, wherein the emulsifier accounts for 2-7wt% of the total weight of the monomers, the oxidant accounts for 0.5-1wt% of the total weight of the monomers, and the reducing agent accounts for 0.1-0.5wt% of the total weight of the monomers.

7. The water-based glue for cigarettes according to claim 6, characterized in that, The monomers are composed of vinyl acetate, ethylene and butyl acrylate, and the mass ratio thereof is 100:(10-20):(1-4).

8. A preparation method of a water-based glue for cigarettes according to any one of claims 1-7, characterized in that, The following steps are involved: The acrylic resin emulsion and the ethylene-vinyl acetate copolymer emulsion are mixed at 50-70° C., and stirred sufficiently to obtain a mixed emulsion. The starch-based component is added, and the mixture is stirred for 0.5-2 hours at a temperature of 1 000 to 200° C. The auxiliary agent is added and mixed. Finally, the solid content is adjusted with deionized water, and the material is filtered to obtain the product.

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