Starch-based aqueous adhesive composition

Abstract

The present invention relates to an aqueous adhesive composition comprising: - a) amylomaltase-treated starch or amylomaltase-treated maltodextrin; and - b) ammonium zirconium carbonate.

Description

Technical Field

[0007] ,

[0001] The present invention relates to starch-based aqueous adhesive compositions.

[0002] The present invention also relates to the use of starch-based aqueous compositions for the manufacture of tubes / cores.

Background Art

[0003] Homopolymer polyvinyl acetate (PVAc) dispersions are widely used and well-established in the bonding in the paper, wood, or paperboard industries, for example in the fields of rigid packaging or the production of cores / tubes.

[0004] Paperboard or paper cores are hollow tubes made of one or more layers of paperboard or paper. These cores are formed by winding a material such as paper or paperboard around a cylindrical mandrel at a predetermined winding angle, and the material is wound such that each winding overlaps at least partially with the previous winding and adheres to itself at the seam or overlap to create a cylindrical core. Such cores are generally used for roll products, which are wound around the core. Cores for paper towels, toilet paper, or the protection of alcohol bottles may be mentioned.

[0005] These cores / tubes are typically manufactured using industrial continuous processes, especially the core winding process. To meet the constraints of high-speed continuous processes used in industry, aqueous adhesive compositions are expected to have a fast curing time, that is, to rapidly cure the bond immediately after applying the composition to form an assembly of two substrates and to maintain this bond after applying pressure for a short time.

[0006] PVAc dispersions typically make it possible to reach a fast curing time. However, more environmentally friendly dispersions are needed.

[0007] Alternatives exist, such as aqueous solutions of dextrin or starch. However, these solutions do not allow for fast curing times, and therefore lead to lower productivity in industrial processes.

[0008] Therefore, there is a need for novel, environmentally friendly adhesive compositions that exhibit fast curing times.

[0009] In particular, there is a need for novel, environmentally friendly adhesive compositions that offer a good balance between adhesive properties and fast curing time, especially for assembling paper or cardboard substrates. [Modes for carrying out the invention]

[0010] The present invention - a) Amylomaltase-treated starch or amylomaltase-treated maltodextrin; and - b) Zirconium ammonium carbonate (AZC) This relates to an aqueous adhesive composition containing [a specific component].

[0011] Amylomaltase-treated starch may also be obtained from natural starch containing 15% to 30% by weight of amylose and 70% to 85% by weight of amylopectin, where the weight percentages are based on the total weight of the natural starch.

[0012] The amylose content may also be determined by the "blue value" method described by Batey Ian et al., "Measurement of amylose / amylopectin ratio by high performance liquid chromatography," Vol. 48, No. 9, pp. 338-344, 1996.

[0013] Maltodextrin is known to be an enzymatic derivative of natural starch. The enzymatic process for obtaining maltodextrin from natural starch is well known to those skilled in the art.

[0014] Maltodextrin is typically classified by the "dextrose equivalent" (referred to as DE), which gives an indication of the average degree of polymerization of starch saccharides. Typically, maltodextrin is as follows: 0 < DE (maltodextrin) < 20 has a dextrose equivalent, and native starch has a dextrose equivalent of zero.

[0015] The dextrose equivalent may be measured according to the standard NF EN ISO 5377 (1994).

[0016] The amylomaltase-treated maltodextrin may be obtained from a low DE maltodextrin having a dextrose equivalent (DE) of less than 10 (0 < DE < 10), more preferably a dextrose equivalent (DE) of less than 5 (0 < DE < 5). ...

[0017] The low DE maltodextrin having a dextrose equivalent (DE) of less than 10, more preferably less than 5, may be derived from native starch, preferably waxy native starch containing more than 95% by weight of amylopectin, and the weight percentage is based on the total weight of the native starch.

[0018] Native starch may be selected from the group consisting of potato starch, wheat starch, corn starch, rice starch, pea starch, tapioca starch, wrinkled pea starch, arrowroot starch, and mixtures thereof. Preferably, the native starch is potato starch.

[0019] The low DE maltodextrin having a dextrose equivalent (DE) of less than 10 (0 < DE < 10), more preferably less than 5 (0 < DE < 5), can be obtained after treatment with an amylose-degrading enzyme, such as amylase, after treatment of native starch selected from the group of waxy starch, such as potato starch or waxy corn.

[0020] The aqueous adhesive composition may contain 20% to 60% by weight, preferably 25% to 55% by weight, and more preferably 30% to 50% by weight (expressed as dry content) of amylomaltase-treated starch or amylomaltase-treated maltodextrin, relative to the total weight of the aqueous adhesive composition.

[0021] Amylomaltase-treated starch can be obtained according to the method disclosed in EP0932444. Amylose-containing starch may be converted to chain-extended amylopectin by alpha-1-4,alpha-1-4,glucanotransferase (amylomaltase EC2.4.1.25). A typical and relevant activity of amylomaltase is that the enzyme breaks the alpha-1,4 bond. This amylomaltase does not decompose the starch, but rather recombines amylose with amylopectin. Finally, amylose is recombined with amylopectin to obtain the desired product. The product can form a thermoreversible gel in water at low concentrations.

[0022] For example, amylomaltase-treated starch can be prepared from an aqueous suspension of potato starch (19-20% w / w). This suspension may be jet-cooked at 150-160°C to dissolve the starch. The product may be cooled to 70°C in vacuum and then the pH may be adjusted to 6.2 using, for example, 6N H2SO4. Next, amylomaltase (2 ATU / g starch) may be added. The solution may be stirred at 70°C for 2-20 hours. The solution may then be jet-cooked briefly at 130°C and spray-dried using, for example, a Compact spray dryer (Anhydro, Denmark).

[0023] According to the present invention, amylomaltase-treated starch is starch that has been treated with amylomaltase at least once. Where amylomaltase treatment is not mentioned in relation to starch, the starch may be natural starch that has not been treated with amylomaltase.

[0024] According to the present invention, an amylomaltase-treated maltodextrin is a maltodextrin that has been treated with at least amylomaltase. If amylomaltase treatment is not mentioned in relation to maltodextrin, the maltodextrin has not been treated with amylomaltase.

[0025] Examples of suitable amylomaltase-treated starches are ETENIA™ starches from AVEBE, such as ETENIA™ 271.

[0026] The aqueous adhesive composition may contain more than 40% by weight of water, preferably more than 45% by weight of water, and even more preferably more than 50% by weight of water, compared to the total weight of the aqueous composition.

[0027] The aqueous adhesive composition may contain 0.10% to 1% by weight, preferably 0.20% to 0.80% by weight, of ammonium zirconium carbonate (dry matter), compared to the total weight of the aqueous adhesive composition.

[0028] Ammonium zirconium carbonate may be introduced into the aqueous adhesive composition as an aqueous solution. An aqueous solution of ammonium zirconium carbonate is commercially available, for example, from Polycoating under the trade name Vernetzer AZC or from Brenntag under the trade name Zirlink. The content of ammonium zirconium carbonate in the aqueous solution, expressed as ZrO2, may be in the range of 15% to 25% by weight, preferably 18% to 22% by weight, based on the total weight of the aqueous solution.

[0029] The aqueous adhesive composition may contain at least one additive selected from the group consisting of biocides, defoamers, plasticizers, rheology modifiers, colorants, wetting agents, pH adjusters, inorganic fillers, and mixtures thereof.

[0030] The total content of the additives may be in the range of 0.1% to 1% by weight, compared to the total weight of the aqueous adhesive composition.

[0031] In a preferred embodiment, the aqueous adhesive composition does not contain a boron compound such as, for example, boric acid or borax. Since borax and boric acid are toxic and are known to be not environmentally friendly, it is preferred to avoid using such components in the aqueous adhesive composition.

[0032] The aqueous adhesive composition may have a viscosity in the range of 100 mPa·s to 5000 mPa·s, preferably 300 mPa·s to 1000 mPa·s, at 23°C. The viscosity is measured using a Brookfield RVT viscometer.

[0033] The aqueous adhesive composition may have a pH in the range of 7 to 10, more preferably 8 to 9, at 23°C.

[0034] The present invention also relates to a method for preparing the aqueous adhesive composition disclosed above.

[0035] The aqueous adhesive composition may be prepared by mixing a) amylomaltase-treated starch or amylomaltase-treated maltodextrin, b) ammonium zirconium carbonate and optional additives, and water. The mixing can be carried out at 23°C.

[0036] The present invention also relates to the use of the aqueous adhesive composition disclosed above for the production of rigid packaging or tubes.

[0037] In one embodiment, the aqueous adhesive composition according to the present invention is used in the production of tubes / cores by core winding. These tubes can be used, for example, in the production of protective materials for paper towels, toilet paper, or alcohol bottles. Preferably, the tube / core is made of paper or cardboard.

[0038] According to the present invention, in <<contained in x to y>> or <<range of x to y>>, it means the range including the limit values x and y. For example, the range of "including 1% to 3%" particularly includes 1% and 3%.

Examples

[0039] viscosity The viscosity of the composition was determined using a Brookfield DV-I digital viscometer (mPa·s) with a suitable applicable spindle (e.g., spindle 2) at 20 RPM, 23°C (±1°C) after 15 seconds.

[0040] pH value At 23°C (±1°C), the pH value was determined after calibrating the electrodes at pH 7 and 10 using a pH / temperature meter TESTO 230 with buffer solutions.

[0041] Adhesive curing time The curing time of the aqueous adhesive composition is determined using a FIPAGO adhesion tester (System PKL) in a controlled room (RH=50±5%, T=23℃±2℃).

[0042] Sample preparation: Before testing, the adhesive was left in a controlled room with RH=50±5% and T=23℃±2℃ for at least 24 hours. The following fragments were cut from Fipago2006 paper (Stohlein, 200g / m2, Cobb1800: 86g / m2). - Apply the aqueous adhesive composition to a 30 x 200 mm piece of paper. - Place a 60 x 100 mm paper strip in the FIPAGO adhesion tester.

[0043] Using a roll coating machine, a thin film of aqueous adhesive composition is applied to a 30×200 paper strip at a rate of 55g / sqm (±5g / sqm) = 0.31-0.35g of aqueous adhesive composition per strip. A 60×100mm paper strip is fixed horizontally to the inclined surface of a measuring machine connected to a movable arm capable of pendulum motion around a pivot axis. The edge of the 30×200 paper strip is brought into contact with a fixed support connected to the machine, which is on the same plane as the preceding object and adjacent to it, with the side coated with the aqueous adhesive composition (approximately 2cm in length). The largest portion of the 30×200 paper strip is then coated onto the 60×100 paper strip, and the machine's press device automatically and uniformly presses it down at the end. This pressing is performed 5 seconds after coating the strip (open time). Next, the adhesive assembly is destroyed by activating the pendulum motion of the movable arm to separate the two substrates.

[0044] The curing time is the minimum time at which the energy exceeds 70 mmKp (0.69 J) with an open time of 5 seconds.

[0045] Example 1: Preparation of aqueous adhesive composition C1 The following raw materials were used in the preparation of the aqueous adhesive composition. ETENIA (trademark) 271: Amylomaltase-treated starch, commercially available from AVEBE in the Netherlands. A zirconium ammonium carbonate (AZC) solution containing 20% ​​AZC, represented as ZrO2, commercially available from VERNETZER® AZC:POLYCOATING GmbH; AGITAN® 301 (Antifoaming agent): A blend of vegetable oil, modified fatty acid compound, nonionic emulsifier, and a small amount of silicone, commercially available from MUNZING CHEMIE ABSTATT; ACTICIDE(registered trademark) MBS (biocide): A mixture of 1,2-benzoisothiazolin-3-one (BIT) and 2-methyl-4-isothiazolin-3-one (MIT), commercially available from THOR.

[0046] The following composition was prepared using the raw materials and quantities listed in the table below. 40g of ETENIA® 271 was slowly dispersed in 58.7ml of water and homogenized until a clear appearance was obtained (time: 1 hour). AZC was added and the mixture was mixed at 23°C for 15 minutes. Next, 0.2g of ACTICIDE® MBS (biocide) and 0.1g of AGITAN® 301 (defoamer) were added and the mixture was stirred at 23°C for 1 hour. The viscosity was measured and additional water was added to reach a viscosity of 500 mPa·s at 23°C. TIFF0007854433000001.tif78170

[0047] Table 1 shows that the aqueous adhesive composition (C1) according to the present invention exhibits an advantageous curing time of 29 seconds. This short curing time is advantageous because it improves the speed of the production line and therefore improves productivity.

Claims

1. - a) Amylomaltase-treated starch or amylomaltase-treated maltodextrin; and - b) Zirconium ammonium carbonate A water-based adhesive composition containing the following:

2. The aqueous adhesive composition according to claim 1, wherein the amylomaltase-treated starch is obtained from natural starch containing 15% to 30% by weight of amylose and 70% to 85% by weight of amylopectin, the weight percentage being based on the total weight of the natural starch.

3. The aqueous adhesive composition according to claim 2, wherein the natural starch is selected from the group consisting of potato starch, wheat starch, corn starch, rice starch, pea starch, tapioca starch, wrinkled pea starch, mung bean starch, and mixtures thereof.

4. The aqueous adhesive composition according to claim 2 or 3, wherein the natural starch is potato starch.

5. The aqueous adhesive composition according to claim 1, wherein the amylomaltase-treated maltodextrin is obtained from low-DE maltodextrin having a dextrose equivalent (DE) of less than 10 (0 < DE < 10).

6. The aqueous adhesive composition according to claim 5, wherein the low DE maltodextrin has a dextrose equivalent of less than 5 (0 < DE < 5).

7. The aqueous adhesive composition according to any one of claims 1 to 6, comprising 20% ​​to 60% by weight of amylomaltase-treated starch or amylomaltase-treated maltodextrin, relative to the total weight of the aqueous adhesive composition.

8. The aqueous adhesive composition according to any one of claims 1 to 7, comprising more than 40% by weight of water compared to the total weight of the aqueous adhesive composition.

9. The aqueous adhesive composition according to any one of claims 1 to 8, comprising 0.10% to 1.0% by weight of ammonium zirconium carbonate (dry substance) compared to the total weight of the aqueous adhesive composition.

10. An aqueous adhesive composition according to any one of claims 1 to 7, comprising at least one additive selected from the group consisting of biocides, defoamers, plasticizers, rheological modifiers, colorants, wetting agents, pH adjusters, inorganic fillers, and mixtures thereof.

11. An aqueous adhesive composition according to any one of claims 1 to 8, characterized in that it does not contain boron compounds such as borax or boric acid.

12. An aqueous adhesive composition according to any one of claims 1 to 9, having a viscosity in the range of 100 mPa·s to 5000 mPa·s at 23°C.

13. An aqueous adhesive composition according to any one of claims 1 to 10, having a pH in the range of 7 to 10.

14. Use of the aqueous adhesive composition according to any one of claims 1 to 11 for the manufacture of rigid packaging or tubes.

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