SK280235B6 - Process for the preparation of an adhesive for the seams of cigarettes - Google Patents

Abstract

A process for the preparation of cigarette seam adhesives based on chemically modified starch, wherein the solid and liquid components are processed to an aqueous adhesive mass by superposition of mixing and comminution stages, which may take place successively in time. The resulting adhesive can immediately be used without further treatment for industrial manufacture of cigarettes, so that a continuous process from the making-up of the adhesive components up to the application of the adhesive is possible.

Description

The invention relates to a process for the manufacture of an adhesive for the manufacture of cigarettes based on chemically modified starches.

BACKGROUND OF THE INVENTION

Aqueous mixtures based on modified starches (CMS adhesive) are described, for example, in DE 3 914 556.5. This adhesive can be used in the manufacture of cigarettes for bonding cigarette paper at a maximum speed of 550 m / minute.

The advantages of said adhesive over conventional adhesives are the high tack with short drying time, the possibility of treating the solids in cold water and also that the adhesive is harmless.

The production of the CMS adhesive according to the above-mentioned patent consists in that the solid part is mixed intensively with cold water as much as possible and the aqueous adhesive mixture is filled into the machine cartridge (cartridges) so as to be free of air bubbles. However, this type of filling is unsuitable for the industrial manufacture of cigarettes.

The solids content of about 20% by weight, which is required with sufficient tack, results in a viscosity which is above the slip limit at a drop of γ = 1.63 at η < 500 Pa.s under normal shear stress with intensive mixing. Due to this unsuitable ratio, it is not possible to automate the production of this adhesive using conventional technical equipment. During vigorous stirring, dry agglomerates are homogeneously distributed in the aqueous mixture, which in practice require a swelling time of 10 to 54 hours. This time is absolutely necessary to avoid tearing off the adhesive film from the cigarette paper in the manufacture of cigarettes where the glued layers of cigarette paper are folded over each other and form a seam. During a swelling of 54 hours, fluctuations in viscosity η = 7% can be detected.

This again means that the described process can only be used discontinuously for the production of said adhesive.

Both during mixing and after the adhesive has swollen, it is necessary to fill the container or cartridge manually, so that the presence of air, which is unsuitable, can be avoided at the stated viscosity. Thus, it is necessary to extract air from the filled reservoir up to a final pressure of 6.6 kPa, whereby a substantial drop in air bubbles can be achieved, but it is not possible to completely exclude air bubbles due to the stated viscosity and diffusion ratios. However, these bubbles are disturbing when applying glue in a cigarette making machine.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process by which an aqueous glue which is practically free of air bubbles for producing cigarettes based on chemically modified starch can be continuously obtained, so that further downstream measures such as container evacuation and the like are no longer required.

SUMMARY OF THE INVENTION

According to the invention, this problem is solved by mixing the solids and the cold water at a temperature of 10 to 20 ° C, simultaneously or sequentially, in order to break down the larger particles and aggregates, thereby dissolving the agglomerate of the solids at the same time. surrounding the smaller solid particles with a solvent.

In addition, mixing and disintegration of larger particles at the same time prevent the formation of gel structures and the destruction of air bubbles that are enclosed in the material. With a treatment time of up to 3 minutes, a ready-to-use product can be obtained. It has been shown that viscosities only when mixing are 1.5 times higher than the combination of the mixing process with the disruption process using the same material and the same shear.

The creep capability thus ensured allows the material to flow into the cartridge or cartridge of the cigarette machine spontaneously, thereby automating the filling from the mixing device until the finished adhesive is placed in the cartridge.

In this way, it is possible to obtain a product having very good tackiness, the viscosity changes in the individual fractions are less than 1% and the air bubbles present have a diameter of less than 100 µm.

In addition to the advantages mentioned above, the homogeneity of the material, the air bubbles and the uniformly low viscosity of the adhesive allow favorable conditions for applying the adhesive in a cigarette machine, such as homogeneous roll application and transfer to cigarette paper at 550 m / min. production of cigarettes.

The aqueous chemically modified starch adhesive composition is preferably 15 to 30 wt. carboxymethylether of potato or corn starch having a degree of substitution of 0.1 to 0.25, wherein part of the carboxyl groups of the compound are linked by ester bond to the hydroxyl groups of the adjacent molecule and the free carboxyl groups are converted to the sodium salt.

Preferably, the ratio of free and esterified carboxyl groups is selected such that the apparent viscosity in the 2% aqueous solution is 500-4000 mPa · s, as determined by a Koppler viscometer at a shear stress of 4.91 kPa. The total content of inorganic salts is preferably less than 2% and the content of heavy metals and other unsuitable ingredients is less than that which is still acceptable for foodstuffs or foodstuffs.

The following examples illustrate the process according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Example

For the manufacture of cigarette adhesive powdered starch containing carboxymethyl groups and cold water with a total salt content of less than 1%, a total hardness of less than 20 ° dH and a temperature of 20 ° C in a ratio of 1: 5 are placed in a rotating kneading machine. rpm. The rotating annular container for mixing these components is provided with circular arc-shaped knives positioned tangentially to the center of the mixing container at an angle of 120 °. At 1450 rpm, these knives ensure vigorous mixing while breaking larger particles, so that within about 3 minutes it is possible to obtain a homogeneous, gel-like, almost air-free blend, a mixture without any subsequent processing. The finished adhesive has a flowability at 28 to 30 ° C, which allows the adhesive to be automatically moved from said mixing container by means of an endless screw practically without transferring air to the corresponding container of the cigarette making machine (cartridge).

Claims (9)

PATENT CLAIMS CLAIMS 1. A process for the manufacture of a chemically modified starch cigarette adhesive, characterized in that the solid and liquid components are treated simultaneously or sequentially in the first step by mixing and in the second step subjected to a process in which larger particles are broken up into an aqueous adhesive composition. maximum peripheral speed of 24.5 m / s, with a slip surface of 800 to 1000 cm ² , for up to 3 minutes. Method for producing a cigarette adhesive according to claim 1, characterized in that the viscosity of the aqueous adhesive composition under standard conditions is preferably 20% by weight with a solids content. below the slip limit. Method for producing a cigarette adhesive according to claims 1 and 2, characterized in that the aqueous adhesive mixture after mixing time preferably 3 minutes at a maximum peripheral speed at _max 24.5 m / s and preferably at a shear surface of 900 cm ² is suitable for immediate use. the use. Method for producing a cigarette adhesive according to claims 1 to 3, characterized in that the mixing and shearing are performed so intensively that the viscosity fluctuations immediately after filling into the container are less than 1%. A method for manufacturing a cigarette adhesive according to claims 1 to 4, characterized in that the air bubbles in the aqueous adhesive mixture have a diameter of less than 100 µm. Method for manufacturing a cigarette adhesive according to claims 1 to 5, characterized in that the preparation of the adhesive and the filling into the container take place continuously without interrupting the flow of material. A method for producing a cigarette adhesive according to claims 1 to 6, characterized in that the solid component comprises 15 to 30 wt. modified starch, namely carboxymethyl ether of potato or corn starch having a degree of substitution of 0.1 to 0.25, wherein part of the carboxyl groups are ester-linked to the hydroxyl groups of the adjacent molecule and the free carboxyl groups are converted to the sodium salt. A method for producing a cigarette adhesive according to claim 7, characterized in that the ratio of free and esterified carboxyl groups is selected such that a 2% aqueous solution has an apparent viscosity of 500 to 4000 mPa · s as determined by a Hppler viscometer at shear. voltage 4.91 kPa. Method for producing a cigarette adhesive according to claims 7 and 8, characterized in that the total content of inorganic salts is preferably less than 2% and the content of heavy metals and other harmful substances is below the limit permitted for food and foodstuffs.