Hot melt adhesive for cigarettes and preparation method thereof

Abstract

The invention discloses a hot melt adhesive for cigarettes and a preparation method thereof, and belongs to the technical field of preparation of special adhesives, the hot melt adhesive for cigarettes comprises the following components: ethylene-vinyl acetate copolymer resin, ethylene-octene copolymer resin, hydrogenated petroleum resin, polyethylene wax, pentalyn and an antioxidant; wherein the ethylene-octylene copolymer resin is copolymer resin with a random copolymer of ethylene-octylene as a main chain and homo-polyethylene as a branch chain, the viscosity of a hot melt adhesive melt can be remarkably improved, the flowability and curing rate of the hot melt adhesive are improved, and the bonding performance of the hot melt adhesive is improved; and the basic hot melt adhesive condition of high-speed operation of the bag sealing and packaging machine can be well met.

Description

Technical Field

[0001] The invention relates to the technical field of special adhesive preparation, and in particular to a hot melt adhesive for cigarettes and a preparation method thereof. Background Art

[0002] In recent years, with the continuous acceleration of the process of industrial automation in my country, the development of hot melt adhesives has achieved remarkable results due to their environmental protection and fast curing speed. At the same time, it also poses higher challenges to the performance of hot melt adhesives. On the one hand, the application of high-decorative packaging materials continues to expand, and their surfaces are mostly decorated with UV varnish, UV ink, double-sided lamination or low surface energy materials. For example, the "soft pack hardening" packaging material for cigarettes in the cigarette industry belongs to this situation. The intermediate material is white cardboard, the front surface of which is coated with UV ink and then rolled with UV varnish, and the back surface is mixed with butadiene emulsion and calcium carbonate, and then glue is applied and rolled to form a smooth surface on both the front and back surfaces, making bonding difficult. On the other hand, the speed of the carton sealing and packaging line continues to increase, requiring a hot melt adhesive that can match the high-speed operation of the carton sealing and packaging machine. This puts forward new requirements for the bonding performance of hot melt adhesives, including aging resistance and melt viscosity.

[0003] The current hot melt adhesive for cigarettes is mainly EVA or polyolefin. EVA resin and polyolefin resin are safe and environmentally friendly, with low viscosity and softening point, which is conducive to gluing. However, they have poor aging resistance and sealing properties and lack of long-lasting adhesion. Using EVA or polyolefin hot melt adhesive to bond them often results in problems such as debonding and loose bonding. Summary of the invention

[0004] In view of the above problems, the present invention provides a hot melt adhesive for cigarettes and a preparation method thereof.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions: A hot melt adhesive for cigarettes, comprising the following components: Ethylene-vinyl acetate copolymer resin, ethylene-octene copolymer resin, hydrogenated petroleum resin, polyethylene wax, pentaerythritol rosin ester and antioxidant; Wherein, the preparation method of the ethylene octene copolymer resin comprises the following steps: (1) The reactor is evacuated and replaced with nitrogen, and the evacuation and replacement are repeated several times, and then replaced with ethylene several times, and the reactor is evacuated again and set aside for use, and a co-catalyst solution is added to the reactor, and the temperature is raised to above 80° C., and ethylene is introduced by a solenoid valve. The temperature of the reactor is raised to above 100° C., and the main catalyst solution is added. The reaction is stirred and reacted for 1-4 hours while maintaining the temperature and pressure, and the reaction is cooled after the reaction is completed; (2) 1-octene is added to the reaction system of step (1), the temperature is raised to above 100° C. again, ethylene is introduced by a solenoid valve, the temperature and pressure are maintained, and the reaction is stirred for 1-4 hours. After the reaction is completed, the reaction system is cooled and the pressure is released, and an acidic ethanol solution is added to dilute the reaction system. The reaction system is stirred sufficiently until no precipitation is precipitated, the precipitate is separated and washed with an ethanol solution, and the ethylene-octene copolymer resin is obtained after vacuum drying.

[0006] In some preferred embodiments, the content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 19-33%.

[0007] In some preferred embodiments, the co-catalyst is methylaluminoxane, and the main catalyst is dibenzhydryl (cyclopentadiene) (9-fluorenyl) zirconium dichloride.

[0008] In some preferred embodiments, in step (1), the reaction ratio of the co-catalyst to the ethylene is 5 mmol / 1 atm, and the reaction ratio of the main catalyst to the ethylene is 2 µmol / 1 atm.

[0009] In some preferred embodiments, the reaction ratio of the 1-octene to the ethylene in step (2) is 4-5 g / 1 atm.

[0010] In some preferred embodiments, the hydrogenated petroleum resin is C5 hydrogenated petroleum resin and / or C9 hydrogenated petroleum resin.

[0011] In some preferred embodiments, the softening point of the polyethylene wax is not less than 100°C.

[0012] In some preferred embodiments, the antioxidant is 2,6-di-tert-butyl-4-methylphenol or pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0013] In some preferred embodiments, the mass ratio of the ethylene-vinyl acetate copolymer resin to the ethylene octene copolymer resin, the hydrogenated petroleum resin, the polyethylene wax, the rosin pentaerythritol ester, and the antioxidant is 10: (5.6-6.4): (4.2-4.8): (3.6-4): (0.8-1.2): (0.01-0.05).

[0014] Another aspect of the present invention is to provide a method for preparing the aforementioned hot melt adhesive for cigarettes, comprising the following steps: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5-1h, and cooling the discharged material after vacuum degassing to obtain.

[0015] The beneficial effects of the present invention are: In view of the problem that the existing EVA resin and polyolefin resin are not firmly bonded and have low aging resistance, the present invention provides a new hot melt adhesive for cigarettes by combining components. The hot melt adhesive for cigarettes introduces branched ethylene-octene copolymer resin on the basis of the existing ethylene-vinyl acetate copolymer resin to improve the bonding performance of the hot melt adhesive, and at the same time adds hydrogenated petroleum resin and polyethylene wax to reduce the melt viscosity and increase the curing speed, and rosin pentaerythritol ester further improves the bonding performance of the mixed resin. More specifically, the present invention first prepares homopolyethylene with terminal double bonds as an intermediate product, and then ternary copolymerizes the homopolyethylene with 1-octene and ethylene to prepare the ethylene-octene copolymer resin. The ethylene-octene copolymer resin is a copolymer resin with a random copolymer of ethylene-octene as the main chain and homopolyethylene as the side chain, which can significantly improve the viscosity of the resin melt, improve the fluidity and curing rate of the hot melt adhesive, and improve the bonding performance of the hot melt adhesive. DETAILED DESCRIPTION

[0016] The present invention is further described in conjunction with the following examples. Example 1

[0017] A hot melt adhesive for cigarettes, comprising the following components by weight: 10 parts of ethylene-vinyl acetate copolymer resin, 6 parts of ethylene octene copolymer resin, 2 parts of C5 hydrogenated petroleum resin, 2.4 parts of C9 hydrogenated petroleum resin, 3.8 parts of polyethylene wax, 1 part of rosin pentaerythritol ester and 0.03 parts of antioxidant; Wherein, the content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 28%, and the melt index is 150g / 10min; The preparation method of the ethylene-octene copolymer resin comprises the following steps: (1) The reactor was evacuated and replaced with nitrogen, and the evacuation and replacement were repeated 3 times, and then replaced with ethylene 3 times, and the reactor was evacuated again and kept ready for use, a toluene solution of the co-catalyst was added to the reactor, and the temperature was raised to above 80°C, and 0.1MPa of ethylene was introduced by controlling the solenoid valve, and the temperature of the reactor was raised to above 100°C, and a toluene solution of the main catalyst was added, and the reaction was stirred and reacted for 2.5 hours while maintaining the temperature and pressure, and the reaction was cooled after the reaction was completed; the co-catalyst was methylaluminoxane, and the main catalyst was dibenzhydryl (cyclopentadiene) (9-fluorenyl) zirconium dichloride; the reaction ratio of the co-catalyst to the ethylene was 5mmol / 1atm, and the reaction ratio of the main catalyst to the ethylene was 2µmol / 1atm; (2) 1-octene was added to the reaction system of step (1), and the temperature was raised to above 100° C. again. Ethylene at 0.1 MPa was introduced by electromagnetic valve control, and the reaction was stirred for 2 h while maintaining the temperature and pressure. After the reaction was completed, the reaction system was cooled and depressurized. An acidic ethanol solution (hydrochloric acid concentration of 0.4 mol / L, ethanol mass fraction of 80%) was added to dilute the reaction system. The reaction system was stirred sufficiently until no precipitation was precipitated. The precipitate was separated and washed with ethanol solution, and vacuum dried to obtain the ethylene-octene copolymer resin. The reaction ratio of the 1-octene to the ethylene was 4.2 g / 1 atm. The softening point of the polyethylene wax is 105°C; The antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); The preparation method of the hot melt adhesive for cigarettes comprises the following steps: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5h, and cooling the discharged material after vacuum degassing to obtain. Example 2

[0018] A hot melt adhesive for cigarettes, comprising the following components by weight: 10 parts of ethylene-vinyl acetate copolymer resin, 6 parts of ethylene octene copolymer resin, 2 parts of C5 hydrogenated petroleum resin, 2.4 parts of C9 hydrogenated petroleum resin, 3.8 parts of polyethylene wax, 1 part of rosin pentaerythritol ester and 0.03 parts of antioxidant; Wherein, the content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 28%, and the melt index is 150g / 10min; The ethylene-octene copolymer resin is a commercially available POE material (POE8480, Dow), The softening point of the polyethylene wax is 105°C; The antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); The preparation method of the hot melt adhesive for cigarettes comprises the following steps: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5h, and cooling the discharged material after vacuum degassing to obtain. Example 3

[0019] A hot melt adhesive for cigarettes, comprising the following components by weight: 10 parts of ethylene-vinyl acetate copolymer resin, 3 parts of ethylene octene copolymer resin, 2 parts of C5 hydrogenated petroleum resin, 2.4 parts of C9 hydrogenated petroleum resin, 3.8 parts of polyethylene wax, 1 part of rosin pentaerythritol ester and 0.03 parts of antioxidant; Wherein, the content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 28%, and the melt index is 150g / 10min; The preparation method of the ethylene-octene copolymer resin comprises the following steps: (1) The reactor was evacuated and replaced with nitrogen, and the evacuation and replacement were repeated 3 times, and then replaced with ethylene 3 times, and the reactor was evacuated again and kept ready for use, a toluene solution of the co-catalyst was added to the reactor, and the temperature was raised to above 80°C, and 0.1MPa of ethylene was introduced by controlling the solenoid valve, and the temperature of the reactor was raised to above 100°C, and a toluene solution of the main catalyst was added, and the reaction was stirred and reacted for 2.5 hours while maintaining the temperature and pressure, and the reaction was cooled after the reaction was completed; the co-catalyst was methylaluminoxane, and the main catalyst was dibenzhydryl (cyclopentadiene) (9-fluorenyl) zirconium dichloride; the reaction ratio of the co-catalyst to the ethylene was 5mmol / 1atm, and the reaction ratio of the main catalyst to the ethylene was 2µmol / 1atm; (2) 1-octene was added to the reaction system of step (1), and the temperature was raised to above 100° C. again. Ethylene at 0.1 MPa was introduced by electromagnetic valve control, and the reaction was stirred for 2 h while maintaining the temperature and pressure. After the reaction was completed, the reaction system was cooled and depressurized. An acidic ethanol solution (hydrochloric acid concentration of 0.4 mol / L, ethanol mass fraction of 80%) was added to dilute the reaction system. The reaction system was stirred sufficiently until no precipitation was precipitated. The precipitate was separated and washed with ethanol solution, and vacuum dried to obtain the ethylene-octene copolymer resin. The reaction ratio of the 1-octene to the ethylene was 4.2 g / 1 atm. The softening point of the polyethylene wax is 105°C; The antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); The preparation method of the hot melt adhesive for cigarettes comprises the following steps: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5h, and cooling the discharged material after vacuum degassing to obtain. Example 4

[0020] A hot melt adhesive for cigarettes, comprising the following components by weight: 10 parts of ethylene-vinyl acetate copolymer resin, 2 parts of C5 hydrogenated petroleum resin, 2.4 parts of C9 hydrogenated petroleum resin, 3.8 parts of polyethylene wax, 1 part of rosin pentaerythritol ester and 0.03 parts of antioxidant; Wherein, the content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 28%, and the melt index is 150g / 10min; The softening point of the polyethylene wax is 105°C; The antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); The preparation method of the hot melt adhesive for cigarettes comprises the following steps: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5h, and cooling the discharged material after vacuum degassing to obtain.

[0021] The basic properties of the hot melt adhesives for cigarettes prepared in Examples 1-4 were measured, and the results were as follows:

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A hot melt adhesive for cigarettes, characterized in that: Includes the following components: Ethylene-vinyl acetate copolymer resin, ethylene-octene copolymer resin, hydrogenated petroleum resin, polyethylene wax, pentaerythritol rosin ester and antioxidant; Wherein, the preparation method of the ethylene octene copolymer resin comprises the following steps: (1) The reactor is evacuated and replaced with nitrogen, and the evacuation and replacement are repeated several times, and then replaced with ethylene several times, and the reactor is evacuated again and set aside for use, and a co-catalyst solution is added to the reactor, and the temperature is raised to above 80° C., and ethylene is introduced by a solenoid valve. The temperature of the reactor is raised to above 100° C., and the main catalyst solution is added. The reaction is stirred and reacted for 1-4 hours while maintaining the temperature and pressure, and the reaction is cooled after the reaction is completed; (2) 1-octene is added to the reaction system of step (1), the temperature is raised to above 100° C. again, ethylene is introduced by a solenoid valve, the temperature and pressure are maintained, and the reaction is stirred for 1-4 hours. After the reaction is completed, the reaction system is cooled and the pressure is released, and an acidic ethanol solution is added to dilute the reaction system. The reaction system is stirred sufficiently until no precipitation is precipitated, the precipitate is separated and washed with an ethanol solution, and the ethylene-octene copolymer resin is obtained after vacuum drying.

2. A hot melt adhesive for cigarettes according to claim 1, characterized in that: The content of vinyl acetate in the ethylene-vinyl acetate copolymer resin is 19-33%.

3. The hot melt adhesive for cigarettes according to claim 1, characterized in that: The co-catalyst is methylaluminoxane, and the main catalyst is dibenzhydryl (cyclopentadiene) (9-fluorenyl) zirconium dichloride.

4. The hot melt adhesive for cigarettes according to claim 1, characterized in that: In step (1), the reaction ratio of the co-catalyst to the ethylene is 5 mmol / 1 atm, and the reaction ratio of the main catalyst to the ethylene is 2 µmol / 1 atm.

5. The hot melt adhesive for cigarettes according to claim 1, characterized in that: In step (2), the reaction ratio of the 1-octene to the ethylene is 4-5 g / 1 atm.

6. The hot melt adhesive for cigarettes according to claim 1, characterized in that: The hydrogenated petroleum resin is C5 hydrogenated petroleum resin and / or C9 hydrogenated petroleum resin.

7. The hot melt adhesive for cigarettes according to claim 1, characterized in that: The softening point of the polyethylene wax is not less than 100°C.

8. The hot melt adhesive for cigarettes according to claim 1, characterized in that: The antioxidant is 2,6-di-tert-butyl-4-methylphenol or pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

9. The hot melt adhesive for cigarettes according to claim 1, characterized in that: The mass ratio of the ethylene-vinyl acetate copolymer resin to the ethylene octene copolymer resin, the hydrogenated petroleum resin, the polyethylene wax, the rosin pentaerythritol ester, and the antioxidant is 10: (5.6-6.4): (4.2-4.8): (3.6-4): (0.8-1.2): (0.01-0.05).

10. A method for preparing a hot melt adhesive for cigarettes according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Weigh each raw material according to the ratio and set aside; S2, mixing the ethylene-vinyl acetate copolymer resin, the ethylene octene copolymer resin, the hydrogenated petroleum resin and the polyethylene wax, stirring and heating until they are completely melted and uniform; S3, adding the rosin pentaerythritol ester and the antioxidant, continuing to keep warm and stir for 0.5-1h, and cooling the discharged material after vacuum degassing to obtain.

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