KR102016464B1 - Modified starch, method for manufacturing the same, adhesive composition comprising the same, and mult-ply sheet manufactured by using the adhesive composition - Google Patents

Abstract

The present invention relates to a modified starch in which starch is modified by an esterification reaction with an organic acid, a method of preparing the modified starch, an adhesive composition containing the modified starch, and a multi-layer manufactured using the adhesive.

Description

Modified starch, method for manufacturing the same, adhesive composition comprising the same, and mult-ply sheet manufactured by using the adhesive composition}

The present invention relates to a modified starch, a method for producing the same, an adhesive composition comprising the same, and a multi-layer manufactured using the adhesive composition.

Cardboard can be roughly defined as "stiff and thick paper." White paper, liner paper, corrugated paper, etc. included in the paperboard vary depending on the type of paper, but a considerable amount of waste paper is used. As such, when the paper is manufactured in multiple layers, it is easy to produce a high basis weight and efficiently use low-grade raw materials to reduce the production cost, as well as to improve physical properties and impart new functionality.

In general, a method of spraying interlaminar non-gelatinized starch to produce a multi-ply paper is widely used. When the starch is sprayed between layers and the paper is passed through the dryer, the starch is gelatinized by the high temperature of the dryer and the adhesion between the layers occurs due to the viscosity of the liquid. However, this effect is greatly reduced by the recent changes in the manufacturing technology of the overlapping layer, and the countermeasure is required.

In order to increase the paper production speed in recent years, as the compression and dehydration are more effectively carried out, the drying time of the paper is reduced, and the water required for gelatinization of the starch sprayed between the layers is reduced, thereby reducing the swelling time of the starch particles. Therefore, the bond strength between layers due to unmodified starch was greatly reduced. In addition, with the increase of speed, the closure was promoted, and the amount of starch remaining in the white water was not held by paper. In particular, if starch is unsuspended in papermaking and continuously accumulated in white water, it may cause problems in the wastewater treatment system such as increased wastewater COD or death of activated sludge, and it may cause side effects that neutralize various additives in wet areas. Can be.

Korean Patent Laid-Open Publication No. 10-1998-0039253 discloses an adhesive for manufacturing a multi-ply paper and a method for manufacturing a multi-ply paper using the same. Specifically, in the case of using an adhesive in the form of a slurry solution prepared by adding silica sol and clay, which is an inorganic substance, to the ungelatinized general starch used in the conventional method, it was confirmed that the interlayer adhesion of the layer was remarkably improved. It is described as. However, there is a disadvantage in that there is a difficulty in using a mixture of inorganic and starch, and strength variation occurs due to the mixing ratio.

Japanese Laid-Open Patent Publication No. 1996-120235 discloses a method in which starch derivatives obtained by lowering starch at the same time, acetylating at the same time, and using dicarboxylic acid esterification in combination can be used for sheet interlayers such as multiple layers. Specifically, the effect of increasing the strength can be obtained by lowering the starch and improving the penetration into the paper. The combination of acetylation and dicarboxylic acid esterization lowers the gelatinization temperature of the starch, thereby improving the interlaminar adhesive strength and paper surface printability. It is described as being able to improve. However, when the above three manufacturing methods are applied at the same time in actual production, the manufacturing cost is high, and the paper voids vary depending on the type of raw materials of the overlapping layer, and thus, there are disadvantages of producing various kinds of modified starches.

Republic of Korea Patent Publication No. 10-1998-0039253 Japanese Patent Application Laid-Open No. 1996-120235

The present invention has been made to solve the above problems of the prior art,

An object of the present invention is to provide a modified starch having a low gelatinization start temperature and a high viscosity using an ester modification technique using an organic acid and a method for producing the same.

In addition, an object of the present invention is to provide an adhesive composition having a low gelatinization start temperature by including the modified starch, to increase the interlayer bonding area to provide excellent interlayer bonding strength, and to minimize environmental pollution.

In addition, an object of the present invention is to provide a multi-layer paper having excellent interlayer bond strength, compressive strength and stiffness by using the adhesive composition.

In order to achieve the above technical problem,

The present invention provides modified starch in which starch is modified by esterification with an organic acid.

The modified starch may have a particle size of 10 to 25㎛.

In addition, the modified starch may have a characteristic that the starting temperature of gelatinization of starch is 60 ~ 75 ℃.

In addition, the modified starch may have a characteristic that the maximum viscosity is 500 to 3500cps gelatin at 60 ~ 75 ℃.

The present invention also provides

a) mixing the starch and the organic acid in the form of a slurry and carrying out an esterification reaction; And

b) after the reaction of step a) is completed, removing the solvent and drying; provides a method for producing modified starch comprising the.

In addition, the present invention

It provides an adhesive composition comprising the modified starch.

In addition, the present invention

It provides a multi-layer prepared using the adhesive composition.

The present invention provides a modified starch having a low gelatinization start temperature and a high viscosity by using an ester modification technique using an organic acid, and a method for producing the same.

In addition, the present invention provides an adhesive composition having a low gelatinization onset temperature, providing excellent bond strength and minimizing environmental pollution by including the modified starch.

In addition, by using the adhesive composition, the present invention has a wide interlayer bonding area, thereby providing excellent interlayer bonding strength, and providing a multi-layer paper having excellent compressive strength and stiffness.

Hereinafter, the present invention will be described in more detail.

The present invention relates to modified starch in which starch is modified by esterification with an organic acid.

Recently, high speed paper machine is becoming more common and the drying process is very short time, and the crimping and dehydration condition is worsened. When general starch is used, the yield is lowered and a large amount of starch remaining in the paper is left unsaturated. There is a problem of decreasing the interlayer bonding force. In addition, there is a fear that the unstarched general starch flows into the wastewater, thereby increasing the load of the wastewater treatment.

Modified starch of the present invention was developed to solve this problem.

Therefore, the modified starch of the present invention is characterized by low gelatinization start temperature and high viscosity.

As a starch used in modified starch according to the present invention can be used general starch (ie, unmodified starch), specifically selected from the group consisting of corn starch, waxy corn starch, tapioca starch, potato starch and sweet potato starch 1 or more types can be used.

The organic acid may be one or more selected from the group consisting of maleic acid, succinic acid, fumaric acid, acetic acid, and the like, and more preferably maleic acid.

In the addition reaction with an inorganic acid, an organic acid should be used because the starch is hydrolyzed with acid so that no esterification occurs.

The modified starch of the present invention may have a particle size of 10 to 25㎛, more preferably 10 to 20㎛. If the particle size is smaller than the above range, it may be dehydrated and lost in the paper manufacturing process. If the particle size is larger than the above range, the nozzle may be blocked in the process, which is not preferable.

Gelatinization start temperature of the modified starch of the present invention may be 75 ℃ or less, 60 to 75 ℃. More preferably, it may be 60 to 70 ℃. If the gelatinization start temperature is higher than the above, the interlayer bond strength is reduced by ungelatinized starch due to the rapid production rate of paper, or because the starch is not retained in the paper unfinished state and accumulates continuously in white water, which may cause waste water problems. Gelatinization onset temperature is required.

In addition, the modified starch may be a maximum viscosity of 500 to 3500cps to 60 to 75 ℃, preferably 1000 to 3500cps, more preferably 1500 to 3500cps. If the maximum gelatinization viscosity exceeds the above range, there may be a problem that the process efficiency is lowered due to the high viscosity in the process, so the above range is appropriate.

In the modified starch of the present invention, the esterification reaction may be performed by adding 0.5 to 4 parts by weight of an organic acid based on 100 parts by weight of starch, and more preferably 1 to 3 parts by weight.

When the amount of the organic acid used is less than 0.5 parts by weight, the gelatinization temperature is not lowered, and the interlaminar bond strength effect is lowered. When the amount of the organic acid is more than 4 parts by weight, the gelatinization temperature is much lowered, but due to the rapid expansion of the starch particles. It is not preferable because dehydration is lowered during starch production.

The present invention also provides

a) mixing the starch and the organic acid in the form of a slurry and carrying out an esterification reaction; And

b) after the reaction of step a) is completed, removing the solvent and drying; relates to a modified starch production method comprising a.

The content described above with respect to modified starch may be applied as it is to the production method.

In the step a), the slurry may include 0.5 to 4 parts by weight of an organic acid based on 100 parts by weight of starch.

The slurry may be an organic solvent and water, or a mixture thereof as a solvent, but it is particularly preferable to use water.

In step a), the esterification reaction is preferably performed at a pH of 6-8.

In acidic conditions with a pH of less than 6.0, the gelatinization onset temperature decrease rate is low and not preferable. In alkaline conditions above pH 8.0, the gelatinization onset temperature decrease rate is low and the viscosity is also low. Preferably, the pH is maintained at 7.0 to 8.0. In particular, low pH and low dehydration time at conditions with pH of 7.0 provide desirable results.

The pH can be adjusted by adding one or more selected from sodium hydroxide and potassium hydroxide.

The reaction of step a) may be carried out for 2 to 9 hours, preferably for 3 to 5 hours.

In addition, the reaction of step a) may be carried out at a temperature of 30 ~ 50 ℃.

In step b), the process of filtering and washing the reactant may be further performed.

In addition, the present invention

It provides an adhesive composition comprising the modified starch of the present invention.

The adhesive composition may further include water, wherein the modified starch concentration is preferably 1 to 30% by weight. However, the concentration of modified starch is not limited to the above range.

The adhesive composition can be preferably used for multi-layer interlayer bonding.

When the adhesive composition is used for the multi-layer interlayer bonding, the interlayer bond strength of the multi-layer by the adhesive composition may be 75 to 130 ft.lb/in ² , more preferably 80 to 120 ft.lb/in Can be ² If the interlayer bond strength is lower than the above range, the interlayer bondage of the multi-layer paper may be weak and there may be a problem of layer separation. If the interlayer bond strength is exceeded, the above range may be appropriate since there may be a problem of low process economic efficiency.

In addition, the present invention

It provides a multi-layer produced using the adhesive composition of the present invention.

The manufacturing method of the multi-ply can be carried out by techniques known in the art, except for using the adhesive composition of the present invention.

Specifically, for example, first, water is added to the modified starch of the present invention to prepare an adhesive composition in a slurry state, and the adhesive composition is sprayed so as to be 0.1 to 5 g / m ² between layers, and 0.1 to 20 minutes After lamination at a pressure of 1 ~ 3 kg / cm ² , and dried at a temperature of 100 ~ 130 ℃ can be prepared in multiple layers.

In addition, in order to increase the internal bond strength of the paper itself, positive starch having a positive substitution degree of 0.06 may be added in an amount of 1 to 3 parts by weight based on 100 parts by weight of the pulp.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention.

Example  1-12: Preparation of modified starch

The starch slurry, which is a mixture of general starch and water, is stirred at 40 ° C. with maleic acid (Example 1-3), succinic acid (Example 4-6), fumaric acid (Example 7-9), or acetic acid (Example 10). -12) was added in an amount of 1 part by weight, 2 parts by weight and 3 parts by weight, respectively, based on 100 parts by weight of starch. At this time, in order to maintain the pH of the starch slurry at 7.0 ~ 7.5 was continuously added NaOH aqueous solution and reacted at 40 ℃ for 4 hours.

After completion of the reaction, filtration, washing and dehydration were carried out and dried in a hot air dryer to prepare modified starch.

Test Example  1: Evaluation of Physical Properties of Modified Starch

For the modified starch prepared in the above example, in order to confirm the problem of starch dehydration during mass production of the product, 500 g of the reacted starch slurry was taken, diluted with twice the water, and the time of complete dehydration was measured and compared with the dehydration time of general starch. COD of the dehydration liquid was measured to confirm the wastewater load.

Moisture was adjusted to around 10% and confirmed the gelatinization temperature and viscosity through the Brabender viscosity graph for the modified starch dried, the results are shown in Table 1 below. Comparative Example 1 measures the gelatinization temperature, viscosity, and dehydration time of the general starch.

Reaction chemicals input
(Part by weight) Gelatinization temperature (℃) Viscosity (cps) Dehydration time (seconds) COD
(ppm) Example 1
Maleic acid One 68.4 1709 177 1280 Example 2 2 65.0 1678 202 2360 Example 3 3 62.1 1624 251 3040 Example 4
Succinic acid One 68.4 990 215 1540 Example 5 2 65.2 1092 181 3480 Example 6 3 63.1 964 208 4580 Example 7
Fumaric acid One 74.2 735 185 3860 Example 8 2 73.4 733 206 4440 Example 9 3 72.1 747 195 6060 Example 10
Acetic acid One 72.9 759 278 2960 Example 11 2 72.0 781 284 5280 Example 12 3 71.6 835 335 7240 Comparative Example 1 - - 75.1 1114 200

As confirmed in Table 1, the use of the ester modification method after the addition of organic acid (Organic acid) shows a lower gelatinization temperature than the general starch, the viscosity is increased, the dehydration time was reduced. Wastewater COD was lower than its 15,000 ppm baseline.

Test Example  2: modified starch particle size analysis

The average particle size of the modified starch of Example 1, 2, and 3 and Comparative Example 1 general starch was measured using MASTERSIZER 2000 (MALVERN. Ltd, UK), and the results are shown in Table 2 below.

Reaction chemicals input
(Part by weight) Particle size
(Μm) Example 1 myriad
Maleic acid One 15.4 Example 2 2 15.4 Example 3 3 14.4

Example  13-16: Preparation of modified starch

The modified starch was prepared in the same manner as in Example 2 except that the pH was changed to 5.0, 6.0, 8.0, and 10.0 during the esterification reaction.

Test Example  3: Evaluation of modified starch properties according to pH

The physical properties of the modified starch prepared in Examples 13 to 16 were measured in the same manner as in Test Example 1, and the results are shown in Table 3 below.

Reaction chemicals PH
Gelatinization temperature (℃) Viscosity (cps) Dehydration time (seconds) COD
(ppm) Example 13 Maleic acid 5.0 70.7 1672 295 5600 Example 14 6.0 68.4 2007 400 3840 Example 2 7.0 65.0 1678 202 2360 Example 15 8.0 66.2 1838 582 2440 Example 16 10.0 69.1 1166 504 3790

As confirmed in Table 3 above, it was confirmed that the gelatinization start temperature was the lowest and the dehydration time was the best under the condition of the reaction pH of 7.0. In acidic conditions below 6.0, the gelatinization onset temperature reduction rate was low, and in alkaline conditions above pH 8.0, the gelatinization onset temperature reduction rate was low and the viscosity was low.

Example  17-20: Preparation of modified starch

Modified starch was prepared in the same manner as in Examples 1 to 3, except that 0.5, 1.5, 2.5, and 4.0 parts by weight of the organic acid was added to 100 parts by weight of starch.

Test Example  4: Evaluation of Modified Starch Properties According to Organic Acid Input

The physical properties of the modified starch according to the organic acid input amount of the modified starch of Examples 1 to 3 and 17 to 20 were measured in the same manner as in Test Example 1, and the results are shown in Table 4 below.

Reaction chemicals input
(Part by weight) Gelatinization temperature (℃) Viscosity (cps) Dehydration time (seconds) COD
(ppm) Example 17 Maleic acid 0.5 70.6 1371 170 1130 Example 1 1.0 68.4 1709 177 1280 Example 18 1.5 66.6 1687 182 1930 Example 2 2.0 65.0 1678 202 2360 Example 19 2.5 63.7 1703 238 3010 Example 3 3.0 62.1 1624 251 3040 Example 20 4.0 60.3 1717 341 3150

As can be seen in Table 4, the lower the organic acid input amount is lowered the gelatinization start temperature decrease rate, the higher the input amount was confirmed that the gelatinization start temperature is drastically lowered but dehydration is lowered. In particular, when the amount exceeded 3.0 parts by weight, the modified starch particles swelled rapidly, resulting in a significant decrease in dehydration.

In addition, in order to confirm the modified starch reaction efficiency of the above embodiment, the reaction was confirmed by measuring the amount of unreacted organic acid in the supernatant by centrifugation of the starch solution in which the reaction of the general starch and the organic acid was completed. As a result, the reaction efficiency was 79% (± 1%) at 0.5 to 4 parts by weight of maleic anhydride.

Example  21-26 and Comparative example  2: application of interlayer bonding Multi-layered  Produce

When the modified starch of Examples 1 to 6 and Comparative Example 1 was applied to paper, a sheet of paper was prepared to check the strength of the multi-layer paper. The hardwood bleached kraft pulp (LBKP) freeness (Canadian standard freeness, CSF) positive for the to beating so that 400ml and enhance the internal bond strength of paper with a single ply during manufacturing can propelled were prepared paper having a basis weight 50g / m ² plants of the starch ( Substitution degree 0.06) was added.

Two sheets of resin paper were prepared and each modified starch of Examples 1 to 6 was sprayed to 1 to 3 g / m ² using a spray device therebetween, and laminated at a pressure of 2.0 kg / cm ² for 1 minute and 120 ° C. Pass through the drum dryer to dry completely to prepare a multi-ply paper.

Test Example  5: Multi-layered  Property evaluation

The interlayer bond strength is Scott Bond Tester (Scott Bond Tester, Precision Scientific, USA), and the compressive strength is KS M 7051-1997 (method of compressive strength test of paper) for the multi-layers prepared in Examples 21 to 23 and Comparative Example 2. , stiffness was measured by TAPPI Standard T489 and the measurement results are shown in Table 5 below.

Starch Organic acid input
(Part by weight) Interlayer Bonding Strength
(ft.lb/in ² ) Compressive strength
(kN / m) Stiffness
(kN) Example 21 Example 1 myriad
Maleic acid One 84 1.40 89 Example 22 Example 2 2 99 1.46 92 Example 23 Example 3 3 110 1.52 104 Comparative Example 2 Comparative Example 1 - - 70 1.36 84

As can be seen from the results of Table 5, when the modified starch of Examples 1 to 3 of the present invention is applied to paper, the stack of Examples 21 to 23, the stack of Comparative Example 2 using the general starch of Comparative Example 1 Compared with, the bond strength, compressive strength, and stiffness of paper were greatly improved.

The foregoing detailed description illustrates the present invention. In addition, the above-mentioned content shows and describes preferred embodiment of this invention, and this invention can be used in various other combinations, changes, and environments. That is, changes or modifications may be made within the scope of the concept of the invention disclosed in the present specification, the scope equivalent to the disclosed contents, and / or the scope of the art or knowledge in the art. The above-described embodiments illustrate the best state for implementing the technical idea of the present invention, and various modifications required in the specific application field and use of the present invention are possible. Thus, the detailed description of the invention is not intended to limit the invention to the disclosed embodiments.

Claims (19)

a) mixing the starch and the organic acid in the form of a slurry and carrying out an esterification reaction; And
b) after the reaction of step a) is completed, removing and drying the solvent;
The slurry in step a) comprises 0.5 to 4 parts by weight of an organic acid based on 100 parts by weight of starch,
The organic acid is a method for producing modified starch, characterized in that at least one member selected from the group consisting of maleic acid and succinic acid. delete The method of claim 1,
The slurry is a method for producing modified starch, characterized in that it comprises water as a solvent. delete The method of claim 1,
Method for producing modified starch, characterized in that the particle size of the modified starch prepared by the method is 10 ~ 25㎛. The method of claim 1,
Method for producing modified starch, characterized in that the gelatinization start temperature of the modified starch prepared by the method is 60 ~ 75 ℃. The method of claim 1,
Method for producing modified starch, characterized in that the maximum gelatinization viscosity of modified starch prepared by the method is 500 ~ 3500cps. The method of claim 1,
The esterification reaction in step a) is a method of producing modified starch, characterized in that the pH is carried out at 6-8. The method of claim 8,
The pH is a method for producing modified starch, characterized in that by adjusting the addition of one or more selected from sodium hydroxide and potassium hydroxide. The method of claim 1,
The reaction of step a) is a method for producing modified starch, characterized in that carried out for 2 to 9 hours. The method of claim 1,
The reaction of step a) is a method for producing modified starch, characterized in that carried out at a temperature of 30 ~ 50 ℃. The method of claim 1,
Method for producing modified starch, characterized in that further performing the step of filtering and washing the reactants in step b).
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