FI61912C - ANVAENDNING AV LIMKOMPOSITION FOER TILLVERKNING AV WELLPAPP - Google Patents

Description

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Patent and Register Board («44) Date of issue of the Act of Accession. - 30.06 82

Patent and ocean registration AmMcm utiagd oeh utl.skrfftun publicurud (32) (33) (31) Pyydaccr utudkeus — Bugird prlorltac 10.09.71 3I.OI.72 France-France (FR) 7132670, 7203118 (71) Rhone-Progil, 6 , rue Piccini, 75116 Paris, France-France (FR) (72) Rene Arpin, Lyon, Bernard Laisney, Lyon, France-France (FR) (7 * 0 Berggren Oy Ab (5 ^) Use of an adhesive mixture for the production of corrugated board - Användning av The present invention relates to an adhesive mixture consisting essentially of an aqueous dispersion of a vinyl polymer having a particle size of 0.05 to 10 μm and an inorganic filler having a particle size of 1 to 25 μm, the dry matter content of which is 40 μm. -85% and optionally containing a water-soluble dispersant, and wherein the vinyl polymer is a copolymer of styrene and butadiene and optionally another monomer containing an ethylene double bond, the proportion of styrene being 50-70% by weight of the total reactants. o-%, with a copolymer content of 10-50% by weight and a filler content of 90-50% by weight of the total composition, use in particular for the production of corrugated board.

The manufacture of corrugated board usually comprises the following steps: first, a paper web, which is usually moistened, is guided between heated corrugated rollers. A fast-adhesive is then applied to one side of the thus corrugated and still hot paper, and immediately thereafter a paper web, commonly referred to as a coating, is placed on the corrugated waves. This operation is usually performed in heat and under pressure. This results in a combination product which comprises a smooth side and the corrugated side, which are coated with glue at glue waves.

This product is commonly referred to as single-sided corrugated board.

If the glue is applied to the free waves of one-sided corrugated board and these waves are covered with another coating, a corrugated board called double-sided is obtained. It is also possible to produce so-called 2-corrugated corrugated cardboard by attaching single-sided cardboard (to the corrugated part of the latter) and 3-corrugated corrugated cardboard to double-sided cardboard.

Given the high production capacity of machines currently used in industry (over 200 m / min), the most important properties of the adhesive used are satisfactory adhesion and rapid curing. The term "tack" commonly used in this industry can be defined as a property of an adhesive that allows it to form an acceptable joint immediately after the adhesive and substrate have come into contact with each other at low pressure. Bonding should usually occur in 0.1 second. Curing can be defined as the property of an adhesive to form a joint between a "cover" and a "corrugation" that is not damaged by stresses on the board. Curing is rapid when it occurs 1-5 seconds after applying the adhesive.

In general, the adhesives used so far, although of varying degrees, have this rapid curing property. These adhesives are usually made of substances based on soluble silicates, such as sodium silicate (SKEIST - HANDBOOK OF ADHESIVES - 1962 p. 92), gelled starch or ungelled starch (6). patent 2,102,937); In addition, it has been proposed to use a mixture of amylases (starch) and a thermosetting resin such as urea formaldehyde resin or melamine-formaldehyde resin (Canadian Patent No. 846,239) to improve certain properties of the cartons to be made.

Most of the compounds listed above have in common the presence of starch, either as the sole ingredient or as the predominant ingredient. This is the case, for example, with German Patent Publication No. 1,179,100, as well as Swedish Patent Publication No. 226,654. However, the downside of these adhesives is that they are made at a relatively high temperature (to break down some or all of the starch). In the manufacture of single-sided corrugated board, the use of a high-temperature adhesive does not present a serious disadvantage, since the formation of corrugations can only take place by means of heated rollers and the application of the adhesive is carried out immediately after the formation of corrugations. In contrast, in the manufacture of double-sided corrugated board, 2-corrugated or 3-corrugated corrugated board, the use of starch-based adhesives requires the cardboard to be transported on heating tables in order to apply the adhesive, break down the starch and dry the cardboard. In addition, for technical reasons, it is difficult to use compounds with a dry extract of more than 20-30%, because then there is a problem of removing a large amount of water.

Swedish Offenlegungsschrift No. 315,402 relates to the addition of hydroxylamine hydrochloride to a terpolymer latex of butadiene, styrene and carboxylic acid. Coatings containing hydroxylamine hydrochloride are reported to be highly resistant to boiling water. Said coatings are useful in backing fabrics such as upholstery fabrics, fabric mats, etc.

The presence of hydroxylamine hydrochloride in the composition of our invention would compromise the stability of the latex, 4 6191 2 so that the latex would tend to flocculate or precipitate, especially when the paper or board is introduced into a coating machine. Therefore, a terpolymer latex containing hydroxylamine hydrochloride is not useful in the paper coating industry.

In other words, the use of "cold glues" adhesives produced at temperatures below 50-60 ° C avoids the "thermal" disadvantage of starch-based adhesives. An adhesive compound suitable for these temperature limits is disclosed in French Patent No. 1,488,773. This compound comprises a clay charge suspended with an aqueous solution containing polyvinyl alcohol and a mixture of titanium oxalate and ammonium bicarbonate.

When this compound is used at a temperature of 25-30 ° C, it provides only poor adhesion between the coating and the waves.

In addition, due to their acidity, these compounds tend to oxidize the sizing device. In addition, the sensitivity of polyvinyl alcohols to water results in them having joints with poor wet strength.

On the other hand, it has been proposed to solve the dewatering problem by using hot-melt adhesives. But in addition to the problem of heating again, i.e. the problem of high energy consumption, this technique can only be used with the special devices described, for example, in French Patent No. 1,532,690.

With the present invention, these difficulties can be avoided.

It relates to the use of an adhesive which can be used in current corrugated board making machines and which can be manufactured and used at low temperatures, but which nevertheless provides a durable adhesive and also has a very high dry matter content.

Other advantages of use will become apparent from the following explanation.

The adhesive mixture is used in particular for the preparation of corrugated board based on an aqueous dispersion comprising a vinyl polymer in the form of particles having a size of 0.05 to 10 .mu.m and a mineral filler having a particle size of 1 to 25 .mu.m in the dry dispersion. 40-85% and optionally containing a dispersant and a plasticizer, and the invention is characterized in that the vinyl polymer is a copolymer of styrene and butadiene and possibly another monomer containing an ethylene double bond, wherein the proportion of styrene is 50% of the total reactants. % by weight, the proportion of copolymer being 10-50% by weight and the proportion of filler being 90-50% by weight of the total amount of copolymer and filler.

Dry matter content means the percentage by weight of products obtained after heating the dispersion for 1 hour at 105 ° C in a drying oven (cf. ISO standard ISO / R 1625-1970 F).

These copolymers are prepared by conventional methods.

The above copolymers, and in particular copolymers containing a copolymerized plasticizer such as butyl maleate, can be used as such.

It is also possible to use an external plasticizer. These plasticizers can be of a commonly used type (phthalates, adipates, azelates, sebacates). Dibutyl or 3-diethylhexyl phthalate is generally used. The amount of plasticizer is usually 5 to 50 percent by weight of the polymer.

Since the compounds of the invention are in the form of aqueous dispersions, it is preferable to use one or more dispersing or stabilizing agents. This substance, which must be water-soluble, is generally an anionic dispersant or a nonionic dispersant.

Examples of anionic dispersants are the salts of sodium or potassium, the salts of phosphoric acids (hexamethasone) and saturated fatty acids containing from 5 to 18 carbon atoms, esters of sulfonic fatty acids with sodium alkoyl sulfenes, sodium alkoyl sulfates, and sodium sulfonates (alkoyl groups). sodium alkoyl sulfosuccinates, potassium alkoyl malonates, condensates of ethylene oxide and alkoylphenol sulfate.

Examples of non-ionic dispersants are polyvinyl alcohols, hydroxyethylcellulose, condensates of alkoylphenols or fatty alcohols and ethylene oxide, vegetable oils containing polyoxyethylene.

Numerous other dispersing or stabilizing agents may also be used, such as those mentioned in "Detergents and Emulsifiers" published in 1964 by John W. McCutscheon, Inc.

Generally, the amount of dispersant is 0.5-10% by weight of the filler.

The filler particles used in the invention are calcium, magnesium, aluminum and barium carbonates, sulphates and silicates.

The particles may be of different shapes or structures. Examples of these fillers are, in particular, calcium carbonate (limestone) in the form of oolite particles or rhombohedral crystals, calcium carbonate or magnesium carbonate (dolomite) (rhomboedric monoxide), aluminosilicate (kaolin) (magnesium) (magnesium) (magnesium) ) (structure orthorhombic), calcium sulphate (gypsum) (monoclinic).

In general, 50% by weight of the fillers used have a diameter of 0.5 to 20.

It is clear that within the scope of the invention, a small amount (for example less than 15% by weight of the weight of said fillers) of other powdered fillers, such as flint, can be used in parallel with the above-mentioned fillers.

The adhesive compounds according to the invention are prepared simply by mixing together the water and the various ingredients mentioned above. This can also be done in several steps; thus, it is possible in the first step to prepare an aqueous dispersion of the softened or non-softened polymer, optionally in the presence of a dispersant, and then to add minerals; can also be started by dispersing the latter substances.

This step can be performed - and this is one of the advantages of the compound of the invention - at room temperature. The invention is, of course, not limited to these conditions. Thus, without departing from the scope of the invention, the compound can also be prepared at a higher temperature, for example 60-80 ° C.

In a variation of these compounds, the water resistance of the adhesives is improved by adding a thermosetting resin to the compound.

It is clear from the above that the adhesive compounds according to the invention are primarily used in the production of corrugated board. In addition to the previously mentioned advantages, the compounds according to the invention do not wear the rollers of the machines, glue rapidly and provide very durable glues. These compounds can, of course, also be used for other purposes, such as gluing paper, wood or leather; however, the invention is not limited to these applications.

The compounds of this second variant have the same advantageous properties as the compounds of the first embodiment. In addition, they are particularly wet-strength, which makes their use in adhesives exposed to water or steam 8 61912 very advantageous. This property is particularly required in the manufacture of corrugated board which is to be stored in a refrigerator, but it is clear that the invention also includes the use of these compounds for gluing all kinds of other materials, such as wood, leather and paper.

The following examples, to which the invention is not limited, however, illustrate the invention and show how it can be applied.

Example 1 The machinery used is a simple corrugated board machine built according to the general principles of machines used in the manufacture of corrugated board on an industrial scale.

The test conditions are as follows: production speed: 100 or 150 m / min paper width: 130 mm theoretical linear compression in corrugated rolls (corrugation): 50 kg / cm.

linear compression in the ironing press (application of the coating on the corrugation): 45 kg / cm.

the gluing system comprises a glue stick, a gluing roller and a roller which adjusts the thickness of the glue layer to 0.20-0.25 mm.

the wavelength is 8.6 mm, height 4.5 mm. There are 116 waves of finished cardboard per meter.

Corrugated paper is paper with a large amount of semi-cellulosic pulp, weighing 112 g / m 2; the wrapping paper is kraft paper with a weight of 150 g / m 2.

The adhesive compound used in this example is an aqueous dispersion containing 30 parts of a copolymer of styrene and butadiene containing 60% by weight of styrene, in the form of particles having an average size of 0.1-2 .mu.m, 0.7 parts of sodium hexametaphosphate, 70 parts by weight. calcium carbonate of Compound A and water to a dry matter content of 75%.

The above dispersion is used at a temperature of about 26 ° C.

The resulting cardboard has the following characteristics: 100 m / min 150 m / min 2

Adhesive layer g / m 16.4 20

The dry strength of the adhesive joint per mz of cardboard (kg / cin) 0.77 0.86

Example 2

Operate with the same machinery as in Example 1.

The adhesive compound used is an aqueous dispersion containing 30% by dry weight of an aqueous dispersion with a dry matter content of 50% and consisting of 37% by weight of butadiene, 59% by weight of styrene and 4% by weight of unsaturated dibasic acid and unsaturated monobasic acid, and 70% dry carbonate with an average diameter of 2.5 microns, 0.7% hexametaphosphate, and 0.1% tributyl phosphate.

This adhesive compound has a dry matter content of 75%, a pH of 7,

The viscosity measured with a Brookfield at 50 rpm is 880 cP and measured with AFNOR cup Nr. 4 58 seconds.

Such an adhesive makes it possible to produce corrugated board at a speed of 150 m / min, with a curing time of 2 seconds. The wet strength of the gluing is 5 hours immersed in water under tension.

The adhesive enables industrial use in good conditions.