FI117718B - Adhesive dispersion for improving water repellency - Google Patents

Description

I · 117718

Adhesive dispersion for improved water repellency

The invention relates to improving the water repellency, or hydrophobicity, of paper or paperboard by means of an adhesive dispersion containing china α and an agent which improves the adhesion of the adhesive to the fiber surface.

Cellulose-reactive adhesives, such as alkenyl succinic anhydride (ASA) or alkyl ketene dimer (AKD), are known to be used as adhesives in paper production under neutral conditions. The gluing chemical is usually added in the form of a dispersion consisting of very small 10 particles in the manufacture of paper and board. The hydrophobicity of the paper produced is essentially dependent on the retention of the fiber surface, the distribution or distribution of the adhesives on the fiber surface, and the adhesives adhering to the active sites on the surface.

One problem is the poor adhesion of the adhesive to the fiber surface. Surface reactions occur only partially and the surface becomes poorly hydrophobic. Often, it is also necessary to age 15 of the bonded surface for effective bonding. This prevents on-machine gluing.

The alkyl ketene dimer (AKD) or alkenyl ketene dimer is preferably of formula (I) wherein R 1 and R 2 are straight or branched hydrocarbon groups having from 8 to 36 carbon atoms and which may be saturated or unsaturated. Ta-20 commonly used hydrocarbon groups are molecules containing 14 to 18 carbon atoms.

(f I • * • V: R 1 - CH = C - CH - R 2: Y: Il (I) • * »«

. · * ·. O - c = O

* · «* · · · * * ·, ···. The AKD dispersions generally have a particle size of less than 1 µm average particle size, which is why they are generally made by high pressure homogenization. and factories specializing in the manufacture of products. Although AKD is reactive and degrades to ketone in aqueous solution, the reaction is slow, especially at low pH, · ♦ · * such as below 4.5, and therefore AKD dispersions can be delivered to the customer as a ready-to-disperse.

The reason for the formation of small particles is not only that the resulting dispersion ί / .ϊ is as stable, indistinguishable as possible, but also that the small particles can promote the spread of the active substance on the pulp and on the surface of the fibrous material. I, e-2 117718, is an essential part of the mechanism by which AKD can forge good water repellency of paper. It has been shown that when AKD covers about 15% of the fiber surface, the amount is sufficient to achieve near perfect bonding. The degree of sizing, hydrophobicity, may be expressed, for example, as Cobb values, which may be determined according to SCAN-P 12:76.

The spread of the alkyl ketene dimer in the paper can be observed by various methods such as atomic force microscopy (AFM), ESCA (Electron Spectroscopy for Chemical Analysis), ellipsometry, and breath pattern technics.

Currently, in the preparation of AKD dispersions, emulsifiability can be improved by using various anionic and / or cationic surfactants, such as ligno-sulfonates and sodium salts of naphthalenesulfonates and fatty amine chloride, which are physically stable and useful for several weeks. The AKD dispersion can be further stabilized using, for example, starch and / or derivatives thereof, and optionally with or without starch, polymers such as polyethylenimine, polyepamine, polydimethyldiallyl or dicyandiamide compounds, polyacrylamide or acid. It is generally known that the amount of stabilizing chemicals is between 1 and 200% by weight of the amount of AKD. The use of polymers can not only improve the stability of the adhesive dispersion but also affect its performance in paper or board.

Surfactants are known to be used to reduce surface tension », v between oil and water. The properties of nonionic surfactants are often described by: V: their ratio of water to fat solubility, HLB (hydrophile-lipo;: 1; phile balance). Surfactants with low HLB values are * * »1 .1 ··. 25 and those with high HLB values are water-seeking. Based on this value, different surfactants can be grouped for different purposes. Surfactants having an HLB of between 4 and 6 are suitable for emulsifying water in oils.

• · * “Those with HLB between 7 and 9 are suitable as wetting agents, ie they help to spread water on surfaces. Those with HLB values between 8 and 18 are generally suitable for emulsifying oily substances in water. For example, surfactants with an HLB of between 13 and 15 are suitable as detergents.

* e · 1 ·. ·· · · ·

It is known that the spread of adhesives on the fiber surfaces is accelerated by the low melting point of the adhesive and the high storage temperature of the bonded paper.

«1 'i · t • 1 · * · · • · · • • • ♦ 3 117718

Hercules EP 580 405 seeks to improve the hot hydrogen peroxide resistance of liquid packaging cartons, and in particular the permeability of cutting surfaces, by using a sizing composition consisting of a cellulose-reactive adhesive such as AKD, a non-cellulose-reactive adhesive such as bistear, ° C, and a thermosetting resin such as the reaction products of epichlorohydrin and polyaminoamide or polyalkylamine. Preferably, the triglyceryl ester is used as the fatty acid ester, which is a highly hydrophobic, waxy compound naturally occurring in fats.

It has now surprisingly been found that the use of an adhesive in combination with glycerol and a mono or diester of ras-10 wax acid or mixtures thereof, in particular, improves the adhesion of the adhesive to the fiber surfaces and acts as enhancers of the adhesive effect of the adhesive.

Thus, according to the invention, there is provided an adhesive dispersion comprising an adhesive and a non-ionic, surfactant, glycerol and fatty acid mono- or di-ester or a mixture thereof.

The monoesters of glycerol and fatty acid with one fatty acid molecule and one glycerol molecule esterified have an HLB of less than 6. The lauric or 1-lauroylglycerol or glyceryl monolaurate (GML) has an HLB of 4.9 and a glyceryl 3 , 3 and glyceryl monostearate have an HLB of 20 3.4.

Glycerol and fatty acid diesters with two fatty acids and one glycerol esterified · · · II are classified as having a HLB value of less than 5. Such are, for example, gly-. ΪSilyl dilaurate with HLB value of 2.0 and glyceryl distearate with HLB value of * * · 3.4. These compounds are known to be suitable for the preparation of water-in-oil emulsions.

* ♦. ** ·. ; The single fatty acid moiety of the glycerol and the mono or diester of the fatty acid used in accordance with the invention may be saturated or unsaturated and preferably contain 10-20 sleeve atoms.

♦ ·.

Examples of preferred mono- and diesters of glycerol and fatty acid with HLB values less than 6 are glyceryl monolaurate, glyceryl dilaurate, glyceryl * ···. monopalmitate, glyceryl dipalmitate, glyceryl monostearate, glyceryl distearate, glyceryl monooleate and glyceryl dioleate. These mixtures may also be used.

* * * • · * * *! '' 4 117718

The amount of said glycerol and fatty acid mono- or diesterm, or a mixture thereof, in the glue dispersion may range from 0.1 to 25% by weight, preferably from 1 to 5% by weight, based on the amount of adhesive.

The adhesive used in the adhesive dispersion of the invention may be any of the cellulose-reactive adhesives mentioned at the beginning of this specification. Alkyl ketene dimers (AKD) are preferred. The total number of carbon atoms of AKD is preferably 20-44. A particularly preferred AKD is one in which the alkyl groups are derived from palmitic acid or stearic acid or a mixture thereof.

The adhesive dispersion according to the invention preferably contains from 0.1 to 20% by weight and particularly preferably from 1 to 5% by weight of an adhesive which, as mentioned above, is preferably AKD.

The adhesive dispersion of the invention may further comprise one or more of the following components: starch-based substances, synthetic polymers, anionic surfactants such as alkylsulfonates, naphthalene sulfonates or their formaldehyde condensation products or lignosulfonates, be primary, secondary, tertiary or quaternary. The cationic surfactants may be mono-, di- or triamines, or various combinations thereof.

According to the invention there is also provided a process for the preparation of a glue dispersion as described above, wherein a mono- or diester of glycerol and a fatty acid or a

»T I

the mixture is mixed with the other components of the adhesive dispersion. Preferably, the process is carried out by first mixing said mono- or diester or a mixture thereof with an oily adhesive, followed by the addition of other components of the dispersion. Said mono- or diester, or a mixture thereof, may also be admixed with the aqueous portion, L, *, followed by addition of other components of the dispersion. It is also possible to mix; said mono or diester or a mixture thereof in a ready adhesive dispersion.

♦ · * ··

The preparation of the adhesive dispersion involves dispersing and stabilizing the adhesive in water using the appropriate components mentioned above. The dispersion can be made by: * · *: a high pressure homogenizer such as Rannie or a rotor-stator disperser such as Ultraturrax. Dispersion technology is generally known per se. Vai- • I ». the method and technique of rendering do not substantially affect the function of the adhesive dispersion shown; *; dence.

• · · # · * * * 5 117718

According to the invention there is further provided a process for the production of glued paper or cardboard, which method comprises adding the dispersion of glue described above to the paper or board pulp, preferably to the stock, during the manufacture of the paper or board.

5 On a paper machine or board machine, the adhesive dispersion can be dispensed either directly or pre-diluted into the water cycle.

According to the invention, the amount of glue dispersion is preferably added to the pulp so that the pulp contains from 0.01 to 0.4% by weight based on the dry matter of the pulp.

In accordance with the invention, one or more tackifying agents, such as highly cationic starch having a charge of 1-2 meq / g and a viscosity of 2500 to 5000 mPas in 30% aqueous solution, chitosan, cationic polymers such as polyethyleneimine, may also be used. polyepiamine, polyvinylamine, polydimethyldiallyl or dicyandiamide compounds or polyacrylamide or anionic polyacrylic acid or their salts or aluminum compounds, for example polyaluminium chloride, sulphate or nitrate or alum.

These compounds may be included in the adhesive dispersion or separately administered to the sapwood.

With the dispersion of the invention, chemicals conventionally added to the pulp, such as retention agents, can be used in the manufacture of paper or board. ^ optical brighteners, dyes and antifoams.

The retention agent can be, for example, cationic polymers and starch and bentonite and silica and aluminum based sols used in combination therewith.

• * * • * • ·

Other Kemi-25 cabbages used in papermaking, such as starch or calcium carbonate, or pulp grade, do not affect the performance of the invention. Also, the order in which chemicals are added to the paper machine or other running parameters of the paper machine does not affect the operation of the invention.

• «. * ·. As stated above, the adhesive dispersion of the invention is used in the manufacture of paper or board to improve the hydrophobicity of the paper or board.

• · · • · * *. A further object of the invention is the use of the aforesaid glycerol and fatty acid mono- or di-esters or a mixture thereof in the manufacture of paper or board for promoting the spreading of adhesives on fiber surfaces. Herein said glycerol and fatty acid mono- or diester or a mixture thereof may be included in the glue dispersion described above.

An advantage of the invention is the improved adhesion of the adhesive to a hydrophilic surface, such as a fiber or silica surface, which can be used as a modeling material. As a result of wider spreading, the water resistance of paper or board made from fibrous pulp is improved.

The invention is illustrated by the following examples.

Example 1 The spread of alkyl ketene dimer (AKD) adhesive was monitored by a steam technique, which has proved to be a useful method. The AKD used was prepared from a mixture of palmitic and stearic acids in a ratio of 1: 1.

In the method used, an AKD droplet with a radius of about 1 mm was applied to a sample surface to be examined, such as a silica surface. The sample was placed in a chamber where the humidity of the air was adjusted to 50% relative humidity. The temperature was raised to 50 ° C for 48 hours. The limits of distribution are indicated by moistening the surface to be examined with water vapor and measuring the non-wetted area. By subtracting it from the area of the original particle, the area of distribution is obtained. To the molten AKD was added the glycerides shown in Table 1 in an amount of 20% of the mixture.

, 1 · 1; 20 Table 1 Used Adhesive Mixtures * 1 • · -. . ...

* · 1 ** '·' Experiment Spread • 1 ···: Diameter O AKD (C16 / C18 50/50) 2.1 AKD + Glyceryl Monolaurate__8J_! ... · 1 AKD + Glyceryl Dilaurate __ ^ 2_ AKD + Glyceryl Monopalmitate__315_ *: ··· AKD + glyceryl dipalmitate__2 ^ 8_ · · • · »· ·

From Table 1, it can be seen that the addition of glycerol mono- or # · ·: 2 diester to the adhesive results in enhanced spreading.

Ml • · • · * · · · · · ...

• 1 · • · * a · ...

2 • a 7 117718

Example 2

The alkyl ketene dimer having a melting range of 45-50 ° C was thawed at 60 ° C and glyceryl monolaurate (Grindtek ML90, Grindsted Products) was added. AKD without glyceryl ester was used for comparison.

The AKD mixtures were dispersed in boiled starch cationized with quaternary nitrogen and having a nitrogen content of 0.35% by weight, using a high pressure homogenizer (Rannie). The dispersion had an AKD content of 1% and a starch content of 1.5%.

The average particle size was measured using a laser diffraction apparatus, Coulter LS 120.

The composition of the pulp used was 40% birch pulp, 40% pine pulp and filler 20% calcium carbonate and pulp starch 5 kg / t. A dose of 1 kg / t AKD was used. 80 g / m 2 test sheets were prepared from the pulp according to Scan-C 26:76. The sheets were assayed for Cobb 60 after ripening for 10 min at 105 ° C. The Cobb values obtained are shown in Table 2.

15 Table 2

Experiment Average par- Cobb 60 (g / m2) __article size (pm) __O-experiment__ri6__31.0 AKD + 1% glyceryl monolaurate__ri6__28,3_ .V: AKD + 5% glyceryl monolaurate__ril__24,3_ • # * · ♦ 1 1 • 1 • · ·

As shown in Table 2, increasing the addition of glyceryl monolaurate • 1 * ·· 'improved the Cobb 60 while decreasing the particle size.

• ·

Example 3 Glyceryl monolaurate (Grindtek ML90) was added to the cooked starch solution.

* 1 AKD having a melting range of 45-50 ° C was dispersed therein according to Example 2.

· 1 »

The sheets were assayed for Cobb 60 after ripening for 10 min at 105 ° C. Table 3 shows the results thus obtained.

4 · 4 · · · · · · «« • · ··· • 44 »·. '···· · ·« · ♦ · ♦ t ·. '8 117718

Table 3

Experiment Average Cobb 60 (g / m2) ________particle size (nm) __ O-test__y> __ 3U) _ 1% GML added before emulsification__115__24.2 5% GML added before emulsification__2j9__24,1_

Although the particle size increases with the high amount of glyceryl limonolaurate imitated in the experiment, the bonding ability nonetheless improves with reference sample 5.

Example 4

Glyceryl monooleate (Capmul GMO-K, Karlshamn) was mixed with molten AKD, which was dispersed in starch solution as in Example 2. The results obtained are shown in Table 4.

Table 4

Glyceryl monooleate from AKD (%) Mean Cobb 60 (g / m 2) _ __ particle size (pm) __ _0__Ml__27A_ 1 1.25 25.1 • ·> • · * · 1 · 1 According to the results, glycerol also produced from 18 carbon atoms the monoester impairs the bonding ability of AKD.

• • • • ♦ · 1 • · 1 · • · • • • 1 • 1 4 * · 1 »» · '• 1 * · • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •.

* ·· • · • · »· 1 ♦ · 1 ··· ...

• · * 1 «· · • • • • J. · • 1 ·· «· · • · • 1 · ♦ ·· * 1

Claims (16)

Adhesive dispersion, characterized in that it contains an adhesive and a non-ionic, surfactant, glycerol and monoester of a fatty acid, wherein the amount of said monoester relative to the amount of adhesive is between 0.1 and 25% by weight. Adhesive dispersion according to claim 1, characterized in that said glycerol and a monoester of a fatty acid have an HLB of less than 6. Adhesive dispersion according to claim 1 or 2, characterized in that the amount of said glycerol and the monoester of the fatty acid relative to the amount of adhesive is between 1 and 5% by weight. Adhesive dispersion according to any one of the preceding claims, characterized in that the single fatty acid moiety of said monoester is saturated or unsaturated and contains from 10 to 20 carbon atoms. Adhesive dispersion according to any one of the preceding claims, characterized in that said monoester is glyceryl monolaurate, glyceryl monopalmitate, 15: glyceryl monostearate or glyceryl monooleate. Adhesive dispersion according to any one of the preceding claims, characterized in that said adhesive is an alkyl ketene dimer. A glue dispersion according to claim 6, characterized in that alkyl; 1; in the ketene dimer, the alkyl groups are derived from palmitic acid or stearic acid, or a mixture thereof. Adhesive dispersion according to any one of the preceding claims, characterized in that it contains 0.1 to 20% by weight, preferably 1 to 5% by weight of an adhesive. · Adhesive dispersion according to any one of the preceding claims, characterized in that it additionally contains a starch-based substance and / or a synthetic polymer. * * * t • · «. 25 A process for preparing an adhesive dispersion according to any one of claims 1 to 9, characterized in that the monoester of glycerol and fatty acid is mixed with other components of an adhesive dispersion, such as an oily adhesive component or an aqueous component. 117718 A process according to claim 10, characterized in that said monoester is first mixed with an adhesive followed by addition of other components of the dispersion. A process for the production of glued paper or paperboard, characterized in that during the production of paper or paperboard, an adhesive dispersion according to any one of claims 1 to 9 is added to the paper or board pulp, preferably pulp. The process according to claim 12, characterized in that an amount of adhesive dispersion is added such that the paper or board pulp, preferably pulp, contains from 0.01 to 0.4% by weight of glue based on the dry matter of the pulp. Use of an adhesive dispersion according to any one of claims 1 to 9 in the manufacture of paper or paperboard to improve the hydrophobicity of paper or paperboard. Use of glycerol and a monoester of fatty acids in the manufacture of paper or board to promote the spread of adhesive on fiber surfaces. Use according to claim 15, characterized in that said monoester of glycerol and fatty acid is included in an adhesive dispersion as defined in any one of claims 1-9. • * • • • • • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · ♦ «» * · · «« «« ««. 11 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 117718