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INVENTION
Patent of the Russian Federation RU2280060
STEIN HALL ADHESIVES WITH HIGH CONTENT OF DRY SUBSTANCE AND METHOD OF PRODUCING STEIN HALL GLUES WITH HIGH CONTENT OF DRY SUBSTANCE
Applicant's name: Tate and Lille N.Yu.
(BE)
The name of the inventor: VANDEVELDE Daniel (BE)
The name of the patent holder: Tate and Lille. (BE)
Address for correspondence: 103735, Moscow, ul. Ilyinka, 5/2, OOO "Soyuzpatent", Pat. I.S. Salomatina
Date of commencement of the patent: 2002.01.30
The invention relates to a process for the production of a high dry matter Stein Hall using one mixing vessel, comprising the steps of: providing a carrier by gelatinizing a first portion of the starch in a medium containing a portion of the alkali necessary to produce an adhesive; Diluting the carrier with water, followed by the addition of at least a portion of the second portion of the starch; Adding the remainder of the second part of the starch and the remaining portion of the alkali in the diluted form necessary for the preparation of the glue. Addition of the remaining second part of starch and alkali is carried out in stages. The technical result is the production of glue with a high content of dry matter, simplification of the technology for its production.
DESCRIPTION OF THE INVENTION
The invention relates to a method for producing a Stein Hall adhesive comprising the steps of:
- obtaining a portion of the carrier as a result of gelatinization in an alkaline medium, at least a portion of the total amount of starch in the glue;
- dilution of a portion of the carrier with a certain volume of water;
- addition of the remaining secondary starch,
Wherein in the first step, said support portion is produced using a portion of the alkali, and in the second stage, the carrier portion is diluted with a certain volume of water, followed by the addition of at least a portion of the secondary starch.
The invention further relates to a Stein Hall glue with a high dry matter content (and called a high-concentration glue or Stein Hall adhesive) produced according to the above-described process.
Starch-based adhesives are well known in the corrugated cardboard industry. Among the glues used, the most popular are Stein Hall type glues.
Stein Hall glues are generally known as glues containing a portion of an adhesive carrier which is obtained as a result of caustic soda gelatinization of approximately 10-20% of the total amount of starch in the glue. The resulting paste is then cooled and diluted with water, and the remaining starch is thereafter added as a granular native starch. And add and borax (1.5-2.5%).
Under these conditions, the maximum total starch concentration in these Stein Hall-type compositions does not exceed 25%, although they were reported as well up to 30-37% in terms of dry weight. Higher values were obtained when the viscosity of the carrier was reduced as a result of the oxidation reaction and the like.
The disadvantage of these low-concentration glues is that they contain significant amounts of water, which reduces the rate of adhesion and makes it difficult to dry the adhesive layer during the adhesion stage. In addition, adhesives with a higher solids content result in reduced energy consumption, since less water will need to be evaporated.
Therefore, higher concentrations of starch in the glue are desirable. But it is also known that when using starch as a binder, there is a limit to the maximum amount of starch that can be used. With higher amounts of starch, the amount of water becomes insufficient to guarantee the desired adhesion, while the viscosity of the glue becomes too high.
Highly concentrated starch adhesives have been disclosed in the prior art. EP 0038627 describes a starch based adhesive that consists of a fully gelatinized starch fraction and a partially swollen starch fraction with a ratio of 0.2: 100 to 2: 1. The adhesive can contain from 10% to 40% of the solid phase of the starch based on the dry weight. The gelatinized fraction is obtained as a result of heat treatment at 95 ° C. or higher, and not as a result of mixing with concentrated alkali, as in the classical Stein Hall composition. Strictly speaking, it is a glue related to the type of adhesives without a carrier, to which a fraction of gelatinized starch is added in the wet state to improve the tackiness of the glue in the wet state.
EP 0 566 221 describes adhesive compositions containing from 15 to 35% by weight of a solid phase of starch. A significant amount of the starch is in a partially swollen state (preferably 20 to 50%).
EP 0376301 describes an adhesive obtained by treating a starch slurry in a jet cooker at a temperature of 120 to 200 ° C. to produce a gelatinized dispersion. After this, a non-pasteurized fraction is added to this gelatinized dispersion. The total solids content of the starch in this composition, as illustrated in the examples, ranges from 32 to 40%.
In GB 1571336, a process for the preparation of a water glue based on starch is described. In this method, the support portion is prepared from a gelatinized molecularly dispersed starch with a solids content of 3% to 40% by weight by cooking a starch slurry using a jet cooker. The carrier portion is thereafter mixed with a slurry of nonclustered starch. An alkali is added to the resulting mixture.
The adhesives described in these applications are not typical Stein Hall compositions.
EP 1 101 089 describes starch-based adhesives with a high dry matter content containing at least 40%, preferably at least 46% dry matter. This high dry matter content is obtained by adding inorganic salts to the glue based on starch, preferably calcium carbonate. The starch / filler ratio is preferably at least 60:40. The glue can be of the Stein Hall type, without media or Minocar.
EP 0409240 describes a highly concentrated glue in the form of a starch suspension containing 20 to 60% by weight of the solid phase of the starch. The glue is stabilized by the addition of a gum such as xanthan gum or ramzane gum and some sodium hydroxide.
WO 9850478 describes high solids adhesive compositions that contain a significant amount of a water-soluble alkaline silicate together with starch, brown and sodium hydroxide. In the examples, glue compositions containing up to 45% of the solid phase are described.
Some of the documents of the prior art cited above do not apply to Stein Hall type adhesives, such as EP 0038627, EP 0576221, EP 0376301 and EP 0409240.
Two other cited documents, eg EP 1101809 and WO 9850478, may include Stein Hall type glues, but they differ significantly from standard compositions in that they contain an inorganic filler material that contributes to a high dry matter content in the adhesive .
In the current state of the art, other adhesives with a high dry matter content of the Stein Hall type have also been described.
US Pat. No. 3,912,531 describes high-dry adhesives of the Stein Hall type containing up to 40% by weight of the solid phase of the starch.
However, a drawback of this type of Stein Hall adhesive with a high dry matter content is that it is obtained when used as a starch carrier or a portion of the starch carrier of flowable starch whose fluidity is from 25 to 90.
EP 0049009 describes adhesives with a high dry matter content of the Stein Hall type. The problem that led to the development of this patent document is to obtain a final glue with a high dry matter content, in which the viscosity will not be significantly increased, and as a result, the mixture can still be pumped. Strictly speaking, the glue should exhibit a certain stability of properties during storage and be characterized by a suitable viscosity for processing.
The patent document states that adhesives with a high dry matter content can not be obtained from the commonly used technology for the production of Stein Hall type adhesives (which have a low dry matter content). As described above, the method by which these types of Stein Hall type adhesives are obtained includes the preparation of a carrier and thereafter diluting it with a reduction in basicity. If the basicity is not reduced, it will have a negative effect on the addition of secondary starch and, as a result, will result in swelling of the granules and unstable viscosity.
However, if it is necessary to obtain adhesives with a high dry matter content, dilution becomes insufficient to prevent undesirable swelling. In addition, the combination of a less dilute carrier and a high concentration of secondary starch will result in a composition that is no longer suitable for processing.
The solution of this problem, which is proposed in EP 0049009, is to oxidize a portion of the carrier, and then gelatinize the oxidized starch in the presence of the required amount of sodium hydroxide, thereby reducing the carrier viscosity to a value that will make it possible to add the required amount of secondary starch. This secondary starch is thereafter added until an adhesive with a dry matter content of 40% is obtained. It should be emphasized that the portion of the starch-carrier in the glue is more than 14% of the dry substance of starch present in the glue.
A disadvantage of this method is that the adhesives with a high dry matter content are obtained when it is necessary to use starches with reduced viscosity in the carrier fraction.
Low viscosity starches mentioned in patent documents of the current state of the art are typically flowable starches or oxidized starches, where flowable starches are produced by chemical or enzymatic degradation.
No. 6,048,391 describes a process for producing a starch-based adhesive for manufacturing corrugated paperboard. The process is carried out in a system that includes a first and a relatively large mixing vessel equipped with a stirrer. The second and smaller mixing tank is connected to the first mixing tank through the recirculation channel. The second and smaller mixing container is equipped with means for generating a shear force that exceeds the shearing force generated in the first and larger mixing vessel. The process is carried out in two stages. In a first step, water and starch are fed to produce a carrier in the first mixing container, and then the resultant carrier is transported to a second mixing vessel. In the second mixing container, a liquor is firstly controlled in a controlled manner to produce a carrier. In the second stage, additional starch, water, borax and a second dose of liquor are added to the carrier in a small container.
The disadvantage of this system is that an additional mixing tank is used, where a circulation loop is introduced. Thus, a technically more complex and more expensive system is obtained. In addition, Stein Hall adhesives obtained by this method do not have a high dry matter content.
It is an object of the invention to provide a method for producing a Stein Hall glue which overcomes the drawbacks mentioned above.
This goal is achieved by using a method for producing a Stein Hall adhesive comprising the steps of:
- obtaining a portion of the carrier as a result of gelatinization in an alkaline medium, at least a portion of the total amount of starch in the glue;
- dilution of a portion of the carrier with a certain volume of water;
- addition of the remaining secondary starch,
Wherein in the first step, said support portion is produced using a portion of the alkali, and in the second stage, the carrier portion is diluted with a certain volume of water, followed by the addition of at least a portion of the secondary starch, where a Stein Hall adhesive with a high dry matter content is produced using a single mixing vessel , Wherein in the first step, said support portion is produced in one mixing container, and in the third stage, the remaining alkali is added in diluted form together with the secondary starch.
In a preferred embodiment of the process according to the invention, the addition of the remaining secondary starch and alkali is carried out in stages.
The advantage of this variant is that the secondary starch is not directly exposed to excessively high concentrations of alkali, thereby preventing premature swelling of the secondary starch.
In a more preferred embodiment of the process according to the invention, the addition of alkali and starch is carried out in at least two stages.
In one embodiment of the process according to the invention, in a first step, a support portion containing 2 to 9% of the total starch content is obtained by stirring the starch together with water and alkali until all of the starch is gelatinized.
In one embodiment of the process according to the invention, in the first stage, the alkali content of the support portion is usually less than 2/3 of the total amount necessary to prepare the adhesive composition.
In one embodiment of the method of the invention, in a second step, the carrier portion is diluted with a volume of water corresponding to 60-85% of the volume of the carrier.
In one embodiment of the process of the invention, from 50% to 75% of secondary starch is added in the second stage.
In a preferred embodiment of the process of the invention, a borax is added after the third stage.
The advantage of this variant is that the initial tackiness is improved and both the retention of water and the glue's ability to penetrate are regulated.
The purpose of the invention is furthermore achieved by developing a Stein Hall adhesive with a high dry matter content obtained by the method described above, wherein
- the glue contains from 32 to 45% of native or stabilized starch;
The ratio of starch-carrier and secondary starch amounts is from 1:50 to 1:11;
- Bauer adhesive viscosity ranges from 21 seconds to 60 seconds;
- the concentration of alkali in the adhesive is sufficient to provide SGP (gelatinization temperature of starch) in the range from 45 ° C to 53 ° C.
In a preferred Stein Hall adhesive with a high dry matter content according to the invention, native or stabilized starch is obtained from starches of cereals, tubers or root crops.
The process for producing the adhesives of the invention comprises several successive steps:
In the first step, a support portion containing 2 to 9% of the total starch content is obtained by stirring the starch together with water and alkali until all of the starch is gelatinized. The alkali content of the support portion is usually less than 2/3 of the total amount necessary to prepare the adhesive composition;
In the next step, the carrier portion is diluted with a volume of water corresponding to 60-85% of the volume of the carrier, followed by the addition of at least half, and at most 75% of the secondary starch;
Then in a subsequent step, the remaining alkali is added in diluted form together with the remaining secondary starch.
The addition of the remaining starch and alkali can be carried out simultaneously or sequentially (stepwise). If the addition is carried out simultaneously, then care should be taken not to expose the starch directly to alkali.
During the stepwise addition of alkali to the mixture of the first and the next steps, the remaining secondary starch is added. The stepwise addition of alkali and starch is preferably carried out in two or more stages.
In conclusion, add borax, completing the manufacture of glue.
Adhesives with a high dry matter content of the Stein Hall type according to the invention are characterized by the following properties:
Contain from 32 to 45% of native or stabilized starch,
The ratio of starch carrier and secondary starch is from 1:50 to 1:11,
The Bauer viscosity ranges from 21 seconds to 60 seconds,
And the concentration of alkali in the adhesive is sufficient to provide SGP in the range of 45 to 53 ° C.
Native or stabilized starch can be obtained from starches of cereals, tubers or root crops. Typical examples thereof are, for example, starches derived from maize, wheat, barley, potato, tapioca or marantha, including waxy starches and starches of a high amylose type.
The stabilized starches mentioned in the application correspond to starches that have been subjected to physical and / or chemical treatment to obtain starches that are less sensitive to alkali exposure at room or slightly higher temperatures. As a result, they are not subject to uncontrolled premature swelling and / or gelatinization.
The advantage of Stein Hall adhesives with a high dry matter content according to the invention and obtained according to the process of the invention is that the production method avoids the use of starches with reduced viscosity in the carrier fraction, the glues still have excellent storage stability and are characterized by suitable processing values Viscosity. They contain only native or stabilized starches. In addition, a final glue with a high dry matter content is obtained, which can be pumped by a pump.
The present invention will be further illustrated by the following examples which are not to be considered as limiting the scope of the invention as such and as expressed in the following claims.
Example 1
Adhesives with a high dry matter content were prepared as follows.
In a capacity of 2000 liters, a carrier fraction was first obtained. Therefore, 16 L NaOH solution at a concentration of 30% (w / w) was admixed to a dispersion containing 28 kg of stabilized wheat starch and 650 L of water. The mixture was agitated with a high shear mixer at 1500 rpm for 10 minutes, allowing the starch to gelatinize. Starch in the carrier fraction was 3.25% of the total starch content in the glue (ratio 1:30).
In the next step, 550 liters of tap water were added to the carrier along with 500 kg of stabilized wheat starch and 3 kg of borax. The whole was mixed at 1500 rpm for another 5 minutes.
Prior to the addition of the remaining alkali and starch, the remaining 12 L NaOH solution at a concentration of 30% (w / w) was first diluted in 100 L of water.
After that, 37 liters of dilute alkali were added to the vessel, followed by the addition of 200 kg of stabilized wheat starch. This mixture was stirred for 5 minutes before adding a second portion of 37 liters of alkali and 138 kg of starch. Again the mixture was vigorously stirred. Finally, while mixing the adhesive, the remaining 38 L alkali and 6.5 kg of borax were added.
Thus, the resulting adhesive composition contained 40% by weight of the solid phase of the starch and consisted of the following:
The glue thus obtained had the following properties:
SGP 47 ° C.
Example 2
This example describes an adhesive containing 40% by weight of the solid phase of maize starch. In a collection of 1500 liters in 440 liters of water, 24 kg of maize starch was dispersed. To this dispersion was added 12 kg of NaOH solution with a concentration of 33% (w / w) and the mixture was stirred using a high shear mixer for 12 minutes at 1500 rpm. Starch in the carrier fraction was 4.2% of the total starch content in the glue (ratio 1: 24).
In the next step, 320 liters of water were added followed by the addition of 4.5 kg of borax and intensive stirring was carried out for 3 minutes. Thereafter, 300 kg of starch was added to the carrier fraction and homogeneously dispersed therein by stirring at 1500 rpm for a further 3 minutes. Before adding the remaining alkali and starch, this additional alkali fraction (10 kg of 33% NaOH) was diluted in 100 liters of water.
Thus, 37 liters of dilute alkali were added to the receiver, followed by the addition of 151 kg of stabilized maize starch, and stirring was performed at 1500 rpm for 3 minutes. After that, a second portion of alkali was added, followed by the addition of 100 kg of starch and dispersion was carried out. Finally, with stirring, the remaining 35 L of alkali was added along with 4 kg of borax.
Thus, the resulting adhesive composition contained 40% by weight of the solid phase of the starch and consisted of:
The adhesive thus obtained showed the following properties:
SGP 48.5 ° C.
CLAIM
-
A process for producing a high-dry-type Stein-Hall adhesive using a single mixing vessel, comprising the steps of:
Obtaining a carrier by gelatinizing the first part of the starch in a medium containing a portion of the alkali needed to produce the glue;
Diluting the carrier with water, followed by the addition of at least a portion of the second portion of the starch;
Adding the remainder of the second part of the starch and the remaining portion of the alkali in the diluted form necessary for the preparation of the glue.
The method of claim 1, wherein the addition of the remaining second portion of the starch and alkali is carried out in stages.
The process according to claim 2, characterized in that the addition of the remaining second portion of the starch and alkali is carried out in at least two stages.
The process according to any one of claims 1 to 3, characterized in that in the first stage, a carrier comprising 2 to 9% of starch from the total amount of starch is obtained by mixing the starch together with water and alkali until all of the starch is gelatinized .
The process according to any one of claims 1 to 3, characterized in that in the first stage, the amount of alkali in the carrier is usually less than 2/3 of the total amount necessary to produce the glue.
A process according to any one of claims 1 to 3, characterized in that in the second stage, the carrier is diluted with a volume of water corresponding to 60-85% of the volume of the carrier.
A process according to any one of claims 1 to 3, characterized in that in the second stage, from 50 to 75% of the second portion of the starch is added.
A method according to any one of claims 1 to 3, characterized in that at the end of the third stage, a borax is added.
-
Glue Stein-Hall with a high dry matter content, obtained according to the method of any one of claims 1 to 8, characterized in that it contains
- From 32 to 45% of native or stabilized starch;
- The ratio of the first part of the starch and the second part of the starch is from 1:50 to 1:11;
- Has a Bauer viscosity of 21 to 60 s; and
- The concentration of alkali in the glue is sufficient to ensure the gelation temperature of starch from 45 to 53 ° C.
Clay Stein-Hall with a high dry matter content according to claim 9, characterized in that native or stabilized starch is obtained from cereals, tubers or roots.
print version
Date of publication 18.12.2006гг
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