FI63081B - PAPPERSPRODUKT MED STOR FYLLAEMNESHALT - Google Patents

Description

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France-France (FR) 7825886 Proven-Styrkt (71) Papeteries Dalle Et Lecomte, Bousbecque (Nord), France-France (FR) (72) Albert Francois Arbon, Lamain Tournai, Belgium-Belgium (BE) (7 ^) Oy Kolster Ab (5U) Paper product with a high filler content - Pappersprodukt med stor fyllämneshalt

The present invention relates to a paper product having a high filler content to give it special properties.

For the purposes of this specification, a paper product is to be understood as meaning a product obtained by a papermaking process, but which may in fact be closely related to both paper, board, etc. and nonwovens ("nonwovens"), blankets, nonwovens, sandwich fabrics, etc.

Attempts have already been made in the past to incorporate fillers into the paper during this manufacture. However, the results obtained have been mediocre because these fillers penetrate the wire and only a small fraction of them remain in the product. Even when retention aids are used and the conditions of use are the best, no more than about 15% by weight of filler can be retained in the product.

In addition, there are already known products consisting of complex sheets, for example for insulating or decorating walls or floors, with a base layer of asbestos cardboard, glass fiber, ceramic fiber or rock wool carpets 2 63081 or blankets. Asbestos is known to be dangerous to health and has more to replace fiberglass or mineral wool based rugs or blankets. But it is even more difficult to attach fillers to these carpets or blankets than to paper, and also because asbestos provides dense, flexible products with a pleasing surface appearance, while requiring little binder, fiberglass and rock wool mats or blankets become very porous, brittle products, with a poor-looking surface.

The object of the present invention is to eliminate these drawbacks and to obtain products with a high filler content by papermaking technology.

The object of the present invention is: 1. to replace expensive materials in the manufacture of a paper product, such as cellulose fibers, asbestos, glass fibers, rock wool, synthetic fibers, etc., with cheap mineral or organic fillers, which may further give the product special properties: 2. obtain dimensionally stable (dimensionally stable) products even when exposed to water and heat: 3. to obtain products with excellent mechanical properties even when exposed to water and heat: 4. to obtain products with permanent fire resistance even when no asbestos is used: 5. to obtain truly rotten & undamaged products: 6. to obtain products with a basis weight (surface weight) of less than 2 out of 20 and more than 500 g / m.

These goals are not limiting and others will appear during the following description.

To achieve these objects, the process according to the invention for obtaining a product using a papermaking technique is significant in that at least one finely divided mineral or organic filler, then at least one first ionogenic agent, is added to the pulp in an aqueous medium to form first groups containing said filler particles and said polarized molecules of the first substance, then at least one second ionogenic substance having the opposite polarity to the first substance, to form second groups containing the first groups and polarized molecules of the second substance, wherein the alternating addition of ionogenic opposite polar substances is stopped when the resulting groups form structures, which can be processed by papermaking processes to obtain said product.

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The pulp is preferably formed from wood pulp. However, this pulp can consist of suspensions of all types of mineral or organic fibers, such as rock wool, ceramic fibers, glass fibers, polyamide, polyester, etc.

The process of the present invention creates molecular structures containing filler particles so as to provide a very strong suspension that withstands shear forces and behaves in papermaking equipment, and in particular on wire, in the same way as pulp, which continues to the presses and dryers of the equipment.

To achieve such a result, the mineral or organic filler must be in a divided form, e.g. in powder or colloidal form, and must have little or no water solubility. The size of the filler particles is preferably mostly 100 microns, although this size is not limiting.

All kinds of mineral or organic fillers can be used to carry out the invention, depending on the desired properties of the finished product.

Chalk, kaolin, talc, dolomite, mica, clay, asbestos, aluminum hydroxide, etc. have been successfully used as mineral fillers. Chalk is often used because of its low price; on the other hand, expensive fillers such as mica are used due to their electrical or electronic properties. Fillers formed from metal powders such as aluminum, lead, etc. powders have also been used successfully.

Powders or emulsions of all kinds of resins can be used as organic fillers; phenolic plastics, amino plastics, epoxy, poly-carbonate *, polyurethane, polyacetate, polyacrylic. powders of polyolefin, polystyrene resins or emulsions of acetate, acrylate, styrene-butadiene, acrylonitrile and the like. Such an organic filler is generally selected on the basis of the specific properties it gives, in particular its binding power.

4 63081 This bonding force can occur either during the drying of the mat with the wire or later during the production of the laminates, as is the case with phenolic resin, which is then exposed to heat and pressure.

The organic filler can consist of ground waste of all types of resins (plastics).

The fillers formed by the resins are therefore added in the preparation of the molecular structures according to the invention in the same way as the rock fillers, but in addition they result in the binder mass to which they are added.

Molecular structures or groups thus obtained by mixing a filler and ionogenic substances together can give plastic paper products which have a very high breaking strength but generally do not have a high enough tear strength. Thus, in order to improve the tear strength of the finished product, it is often advantageous to add these reinforcing fibers such as glass fibers, synthetic fibers, etc. at the same time as the fillers. It is advantageous to add these reinforcing fibers to the wood pulp at the same time as the fillers before adding the ionic substances in order to obtain the good dispersion and good homogeneity necessary to obtain a good quality end product.

In the process of the invention, the molecules of ionogenic substances join together the elementary particles of fillers to form separate molecular structures that can be kept in suspension by stirring and that are capable of withstanding shear. This result is achieved by sequentially treating the filler particles with ionogenic agents having alternately opposite porosity to form ever longer and longer chains.

The choice of these ionic substances (molecular weight and ionogenicity), their order of addition, their dosage and their molecular structure is of great importance for binding the filler particles with sufficient coupling force to make the pulp resistant to shear.

Such ionogenic agents are generally selected from a range of polymers and excipients, with experiments showing that it is sufficient to use 3-5 different polymers and often 4 to achieve the desired results. These polymers are preferably added in ascending order of 5,63081 molecular weight, although this is not mandatory, as will be seen later in Example IV.

It is known that the largest macromolecules currently known have molecular weights that can reach 15,000,000 and are of the anionic type. Their ionogenicity is of the order of 70%. On the other hand, cationic polymers have lower molecular weights, e.g. of the order of 5,000,000, but their ionogenicity can reach 100%.

The action can be as follows:

At least an equally fine filler, e.g. chalk, is dispersed in the aqueous pulp into the pulp while stirring constantly to achieve good homogeneity. A first ionogenic polymer, e.g., a cationic polymer such as a polyamide epoxy resin, a polyester epoxy resin, etc., is then added.

One or more molecules of this first ionogenic polymer are then agglutinated to form separate first groups on the different particles of the filler, which in the selected example have a positive electric charge.

If a second ionogenic, opposite polar (anionic type in the present example) and higher molecular weight polymer is also added, which additionally takes into account the binding force (such as latex, cellulose ester, etc.), then the negative molecules of the second polymer collect numerous first groups to form second, more complex groups.

The present addition of a third ionogenic polymer having the opposite polarity to the second (i.e., cationic type in the present example) and which is even more molecular and is e.g. polyacrylamide or a linear polyamidoester resin allows the formation of third groups which must be obtained by the molecular weight of the third polymer.

By adding a fourth ionogenic polymer having the opposite polarity to the third, i. unique type in the selected example (e.g., a very long and straight chain carboxyvinyl polymer), even more complex fourth groups can be obtained by linking said third groups with fourth polymer molecules, etc. until

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The amounts of polymers added in each step, as well as the reaction times present in each step, are relevant to the quality of the final product because there is an interaction between all the polymers. However, it is difficult to define precise boundaries for these specific cases in each case. In each particular case, the nature of the ionogenic substances, the order of their addition, the amounts of addition and the reaction times are selected to obtain groups of filler particles which give the pulp the required strength in the paper machine used, e.g., a flat wire machine or a hydroformer type with inclined wire.

The process according to the invention can, of course, be carried out batchwise or continuously. In the first case, the production of the stock is carried out intermittently (very much), whereby the batches are stored in vats with a very long mixing time, which forces the shear effects to be taken into account during this mixing time and the addition of ionogenic substances in large quantities.

In continuous operation, the stock is used immediately after its formation and its shear strength may be lower, which makes it possible to reduce the quantities of ionogenic substances and possibly the amounts of these substances used.

Examples of amounts and reaction times in specific cases of preparation of the determined products are given in the following examples.

Example I

Manufacture of dimensionally stable (dimensionally resistant) refractory wall paper, 2 basis weight 100 g / m, according to a discontinuous method following conventional papermaking techniques.

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The following substances are fed successively into a 10 m hydropulper: 8,000 liters of water 70 kg of lightly ground chemically bleached pulp 120 kg of standard grade powder chalk 120 kg of standard grade aluminum hydroxide 30 kg of glass fibers and 2.4 kg of pre-diluted 5% polyamide resin.

The mixture is allowed to react for 1 minute, after which the following is added to the suspension: 7,63081 48 kg of a copolymer resin of vinylidene and acrylic, the mixture is reacted again for 1 minute before 1.6 kg of cationic polyacrylamide resin having a molecular weight of 1 million are added and the mixture is reacted for 2 minutes , then 0.18 kg of carboxyvinyl polymer is added and the mixture is allowed to react for 1 minute.

A 5% suspension of the material thus obtained is diluted to 2.5%, then stored in a vat for feeding to a flat wire paper machine. The paper machine produces a final product with the following characteristics: 2 - basis weight: 100 g / m - thickness: 200 micrometers - cutting force in the dry state: - machine direction 150 N / 5 cm - cross direction 110 N / 5 cm - cutting force in the wet state: - machine direction 60 N / 5 cm - transverse direction 48 N / 5 cm - dimensional stability (dimensional stability) after 8 d immersion in water: change below 0.01 mm / m - elongation at high temperature (10 min at 200 ° C) less than 0.2% - elongation i.e. deformation in fire: non-combustible - approximate calorific value: 5000 J / g.

Example II

Manufacture of asbestos - replacement cardboard. As 3 above, the following was fed successively to a 10 m hydraulic pulper: 8000 liters of water 30 kg of unground pulp 400 kg of chalk from normal quality powders 72 kg of glass fiber 0.5 kg of polyamide epoxy resin (reaction time 1 minute) 45 kg of styrene vutadiene resin (reaction time 1 min) 1.3 kg of polyamine 2 min) and 0.07 kg of carboxyvinyl polymer (reaction time 1 min) 8 63081

According to the layout of the paper machine, cardboard (cardboard) with a basis weight of 250 ... 500 g / m and a thickness of 400 ... 600 micrometers is obtained, the other properties are as follows: - cutting force in dry condition: - machine direction 120 ... 180 N / 5 cm - transverse direction 110 ... 160 N / 5 cm - cutting force in wet condition: - machine direction 40 ... 55 N / 5 cm - transverse direction 35 ... 50 N / 5 cm - elongation or deformation: - at high temperature Qo min 200 ° C) below 0.2 ° / oo - in case of fire: non - combustible - approximate calorific value: 3550 J / g.

Example III

The process of Example II is repeated, but half of the chalk powder, i.e. 200 kg, is replaced by an equal amount of talc.

The final product obtained has the same properties but a smoother surface.

Example IV

Continuous manufacture of cardboard for impregnation.

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The following is fed successively to said 10 m hydrapulper: 8000 liters of water 40 kg of unground pulp 440 kg of standard quality chalk powder and 20 kg of glass fibers

The resulting suspension is continuously stirred and fed continuously to a multi-stage reactor consisting of chambers equipped with stirrers, into each of which an ionogenic polymer is injected by a metering pump. To prepare a dry product, the 50 kg / min feed operation is as follows: - 0.25 l / min epoxy polyamide in the first chamber - 0.08 kg / min carboxylic resin in the second chamber - 0.25 lg / min polyacrylamide resin in the third chamber.

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The reaction time in each chamber is 1 min for polyamide epoxy and carboxyvinyl resin and 2 min for polyacrylamide. Example V

Manufacture of paper products without cellulose fibers. The following is fed successively to the hydraulic pulper: 2000 liters of water 5 kg of ceramic fibers 75 kg of normal quality chalk powder 5 kg of vinylidene-acrylic copolymer resin 5 kg of acrylic resin 10 kg of glass fibers 0.2 kg of polyamide epoxy.

The mixture is allowed to react for 1 minute, then 0.012 kg of carboxyl vinyl polymer is added to the suspension and the mixture is again reacted for 1 minute, after which 0.048 kg of polyacrylamide resin is added, and the mixture is allowed to react for 1 minute.

The suspension thus obtained, i.e. the pulp, is fed into a paper machine to obtain a cellulose-free planar product with a basis weight of 2 250 g / m 2 and having the following characteristics: - cutting force in the dry state: - machine direction 70 N / 5 cm - cross direction 60 N / 5 cm in condition: - machine direction 25 N / 5 cm - transverse direction 20 N / 5 cm - dimensional stability after 8 d immersion in water: change less than 0,01 mm / m - elongation or deformation at high temperature (10 minutes at 200 ° C) less than 0, 2 ° / oo.

The invention thus makes it possible to obtain paper products which, due to their composition, water resistance, porosity, dimensional stability and fire resistance and the uniformity of the surface provided by the technology used, can be used for many purposes, e.g. insulation (coating, insulation boards, composite structures, etc.). in coating (coating substrate, spacer, wall papers or wallpaper, etc.), filtration (painting cabins, dust removal, high temperature filtration, etc.), production of laminates, etc.

The advantages of the present invention include the following: 1. The possibility of producing paper products with a very high proportion of filler.

2. Possibility to use cheap fillers provided they are in a divided form.

3. The possibility of obtaining paper products which have special properties as a result of the use of fillers.

4. Possibility to obtain paper products with the desired density and / or porosity by arranging filler particle sizes.

5. The possibility of obtaining asbestos-free paper products with similar characteristics to asbestos-based products.

Claims (13)

A process for making a disc-shaped product by means of paper-making technique, wherein at least one finely divided inorganic or organic filler is added to a fibrous pulp in an aqueous medium, characterized in that it comprises the following steps: a) adding the fibrous pulp containing the added filler is a first ionogenic substance having a polarity opposite to the polarity of the fiber mass; b) adding a second ionogenic substance having a polarity opposite to the polarity of the first ionogenic substance; c) continuing the addition of ionogenic substances whose polarity alternates successively until stability of the fiber pulp containing the added filler and ionic substances is high enough for processing by paper making technique. 2. A process according to claim 1, characterized in that the number of ionic substances added is at least three. 3. A process as claimed in claim 1, characterized in that the number of ionogenic substances added is at least four. Method according to claim 1, characterized in that the fiber mass containing the added filler is added successively: a) a first high ionic cationic resin having a relatively low molecular weight, b) a first anionic resin having binding properties, c) second high ionic cationic resin having a molecular weight higher than the molecular weight of the first cationic resin; d) a second anionic resin having the highest possible molecular weight and being highly reactive with respect to the second cationic resin. 5. A process according to claim 1, characterized in that the inorganic fillers are chalk, kaolin, talc, magnesium oxide, dolomite, mica, clay, asbestos, aluminum hydroxide, aluminum, lead or the like. 6. A process according to claim 1, characterized in that the organic fillers are phenoplast.