DE845311C - Process for applying or introducing water-insoluble coating or impregnating agents onto or in cellulose fiber materials - Google Patents

Description

(WiGBl. P. 175)

ISSUED JULY 31, 1952

.- / 4447 ir b 155 f

The main methods of incorporating resins, waxes, water and grease repellants, binders or similar impregnating agents into pulp or paper sheets have been that the molded sheets or articles are impregnated with aqueous or organic solutions or dispersions of the material to be incorporated, or that the impregnating agent is in shape an essentially water-insoluble, dry, pulverulent material was added to aqueous fiber suspensions or precipitated from its aqueous or organic solution or dispersion or emulsion in the fiber suspension. For example, it is common practice to add fillers, such as clay, and finishing agents, such as resin soap, resin or wax emulsions or dispersions, rubber milk or asphalt emulsions, to the paper pulp in the Hollander or at any other stage before sheet formation, with alum before or after is added. In this process, the finishing agent is precipitated and the precipitated flakes are enclosed in the paper stock or mixed with it and thus transferred into the finished paper. This mode of operation is satisfactory wherever only small amounts of certain materials are to be introduced into the paper, for example in amounts of 0.5 to 5.0% of the fiber weight. On the other hand, serious operational difficulties often arise when attempts are made to incorporate large amounts of impregnant by these methods. You will often encounter some or all of the following difficulties: i. The resinous product clumps together rather than flakes of small particle size. As a result, when the impregnated pulp runs up on a paper machine, the sheet will stick to presses, dryers, felts and

Calendering causes; 2. The coverage of the individual fibers can be poor; 3. the distribution of the resin in the sheet can be uneven, causing a mottled appearance and uneven absorbency for ink; 4. The foliage is often poor; 5. the precipitation of the Resin is often incomplete, and $ 8 is a big one Share of the resinous impregnating agent in the white water (waste water) lost; 6. the resin agglomerates and the unprecipitated resin will tend to settle in pipes, containers or other parts of the l'apaper manufacturing plant in the form of adhesive aggregates to discontinue.

Some of these difficulties, such as the formation of ilarz stains and agglomerated lumps' Materials, occur frequently in paper mills, even if as little as 0.25 to 3% certain Types of resin and wax emulsions can be added.

The present invention now relates to a method for applying or introducing coating or impregnating agents onto or in cellulose laser materials before their matting and deformation, which is the major part of the difficulties mentioned avoids and which allows not only a more even and more complete coating or impregnating the cellulose fibers, but also a variety of impregnating agents in such a way to bring on or into the interior of the fiber material that the added substances the usual procedure for the production of sheets or preforming from pulp in the common papermaking plants do not bother, even if large amounts of the impregnating agent are used will. The method also eliminates many of the difficulties commonly associated with coagulation Resin-containing dispersions occur by means of inorganic precipitants such as alum, including those difficulties caused by uneven covering of the fibers of the paper stock, through formation of aggregates of the precipitated material and by 'the extraordinarily slow withdrawal of the Water is created from the agglomerated fiber-resin masses lying on the paper machine screen.

The invention also makes it possible to use the apparatus commonly used for the preforming and final shaping of paper stock easily manageable sheets, cardboard boxes and preformed products to manufacture which new Combinations of fibers or of fibers and fillers with certain specific resinous ones Contain impregnating agents, which the latter has so far not been successful by treating the fiber suspensions were incorporated. For example, certain special thermosetting resins or condensates, such as urea-formaldehyde resins, phenol-formaldehyde resins or alkyd resins to the paper stock be incorporated in amounts necessary for the processes of preforming or molding are. A wide variety of thermoplastic resins or elastomers can also be used in a similar manner in the lamination and shaping processes necessary, large amounts are introduced. Furthermore, a large number of organic binders, finishing agents, oils, Waxes, pitch, gums and natural resins, and various combinations as appropriate of two or more resins incorporated into cellulosic fiber materials. ■

By using the method according to the invention, paper or paper impregnated with resin Cardboard of higher quality as well as by processing the treated paper or pulp common methods, such as lamination, molding, pressing, calendering or pressing, new types from. Products are manufactured. Instead of deforming the treated fibers or pulp, you can they are also torn, cut up or ground to produce new types of [insulating materials, pressed powders or to obtain fillers for molding or casting resins.

The present invention now relates to a method for applying or introducing water-insoluble Coating or impregnating agents, such as waxes, bitumen, rubber, resins, elastomers or thermoplastic or thermosetting synthetic resins, on or in cellulosic fiber materials, and it consists in suspending said fibers in water, the aqueous fiber suspension an aqueous dispersion which contains the coating or impregnating agent in a flake-free state, adds and the coating or impregnating agent by means of a colloidal, aqueous dispersion of positively charged partially polymerized «! Melamine-aldehyde condensation products, preferably Melamine-formaldehyde condensation products, flocculates in the presence of the suspended fibers.

It has been found that in such a system the positively charged melamine-aldehyde condensation product a flocculation regulated in this way causes the particles of the coating or impregnating agent be evenly distributed on the cellulose fibers. When dispersed or flake-free Coating or impregnating agents are applied or incorporated in this way, retain the cellulose fibers their property of matting or turning into leaves or other shaped objects molded, despite the presence of large amounts of these agents, which in some cases even can be greater than the weight of the cellulose fibers themselves. In addition, if appropriate Amounts of positively charged melamine-aldehyde condensation product are applied in the manner described above, the flocculated material retained by the cellulose fibers to a high degree. This prevents losses and deposits of organic material in the white water (wastewater) largely avoided.

The special type of flocculation that can be achieved by adding an aqueous, colloidal dispersion of melamine-aldehyde condensation product to an aqueous dispersion, e.g. B. to a through Polystyrene dispersion obtained by emulsion polymerization will be described in more detail later and explained.

It was also considered a significant advantage of the present Invention found that the special Ausfloekvirküng of the colloidal, positively charged Melamine - aldehyde condensation product persists and in many cases is increased after the condensation product has been adsorbed by the fibers of the cellulosic material. The meaning This fact lies in the fact that it was evenly distributed over and in the fiber material Melamine - aldehyde - condensation product uniform deposition and adsorption of the coating or impregnating agents on the fibers after flocculation. It can therefore be great Amounts of any desirable coating or impregnating agent on cellulosic fibrous material such as Paper stock, are deposited, the fibers retain their felting properties, so that they can after the Covering or impregnating still matted together and after the usual wet deformation or

ao papermaking process into sheets or shaped Products can be molded.

The flocculants useful in practicing the present invention are disclosed herein as positively charged melamine-aldehyde condensate

A $ sation products are referred to are resinous melamine-containing substances which have a positive electrical charge in aqueous dispersions. These colloidal resin dispersions can be prepared by dissolving common melamine-aldehyde condensation products, such as methylolmelamines, in acids, e.g. B. hydrochloric acid, acidified or acidic resin solutions are formed, which have a glass electroderi-pn- \ Vert between about 0.5 and about 3.5, measured with a dry content of the solution of 15%, or pn values up to 4, 5, measured on more dilute solutions, and can be produced by aging these solutions to the colloidal state.

Another class of positively charged mel-amine-aldehyde condensation products, which can be used in practicing the present invention are the resinous melamines - Urea - aldehyde - condensation products, such as formaldehyde condensation products, which 0.7 mol of melamine per 4 mol of urea and about ι to 4 mol of bound formaldehyde for every 1 mol Contain melamine urea. These positively charged koudensationsprodukte are obtained by first an acidified solution of a melamine Ilanistoff - aldehyde - condensation product, the ι to 70 mol percent urea and 99 to 30 mol percent Melamine and, depending on the strength of the acid, about 0.2 to 1.5 mol of acid for every 1 mol of melamine contains, produces and lets the solution age until the colloidal, positively charged state is reached. Essential requirement for those usable as flocculants in the present process Aminotriazine-aldehyde condensation products is that they are dispersible in a water or hydrophilic, partially polymerized state and that they have a positive electrical charge own. Any aminotriazine-aldehyde condensation products, which have these characteristic properties can be used.

Any water-insoluble coating or impregnating agent can be used by means of the present process can be used in amounts from a few percent to more than the weight of the fiber. Under coating or impregnating agents are of course to be understood as products that are capable of improving cellulose fibers of use value to coat or impregnate. Most of the coating or impregnating agents used for the implementation of the present process come into consideration are, organic, amorphous or microcrystalline Substances such as waxes, rubber, elastomers or resins, paraffin, waxes obtained from petroleum, Carnauba wax, montan wax, chlorinated waxes, natural and synthetic gums, natural, where appropriate modified resins, natural or synthetic latices, polymers of isoprene, iveoprene, Butadiene or copolymers of these with acrylonitrile, thermosetting resins of the phenol-formaldehyde, Alkylphenol-formaldehyde, urea-formaldehyde and alkyd resins, not positively charged Melamine formal deliyd resins, alkylated or urea form reacted with alcohol

; aldehyde or melamine-formaldehyde resins, furthermore

j thermoplastic resins of the type of polymers or copolymers of styrene, acrylates, Methacrylates, vinyl esters, vinyl chloride. Vinyl acetals, vinyl alcohol, acrylonitrile, as well as thermoplastics Phenol-aldehyde resins, oil-modified phenol-formaldehyde resins, resin esters of more

! valuable alcohols, resins made from melamine and

j higher aldehydes, indene, coumarone, vinyl acetylene resins, halogenated vinyl acetylene resins, acetyl rubber and others more.

All of the above substances can be used alone or in a mixture with one another, by means of positively charged Melamine-formaldehyde condensation products by the process according to the invention in Cellulose fiber materials are applied or introduced. The impregnant is used as a dispersion

: added in water or in an aqueous liquid to the aqueous fiber suspension. At different Types of impregnating agent, an addition of emulsifying or dispersing agents is not necessary, no such as B. with natural rubber milk. In many cases, however, dispersants are used Dispersions of finer particle sizes and

! get better impregnation properties. There can be several types of dispersants be used. In general, any anionic or non-ionic dispersant can be used into consideration. In some cases, cationogenic emulsifiers can also be used. Typical anionogenic emulsifiers which have been used with no success are aliphatic soaps or cycloaliphatic sulfonated compounds such as sodium lauryl sulfate, sulfonates higher secondary alcohols and sulfonated castor oil, sulfonated products such as sodium isopro-1 * 5 pylnaphtlialiusulfonat, ester of sulfocarbon-

acids such as esters of sodium sulfoacetate, dialkylsu 1 fos ucc inate, D inat r ium monoalky 1 su 1 fosucci na t, also amides of sulfocarboxylic acids, such as sodium sulfosuccinamide and the like or sulfonated Lignin.

Non-ionic emulsifiers, such as esters or ethers of polyhydric alcohols, can also be used. Typical representatives of this class are malic acid of the formula HO- (CH ₂ OVCH ₂ -O-CH (COOR) -Ch ₂ -COOR, monoesters of higher fatty acids, such as palladium, stearic or oleic acid monoesters of mannitol or sorbitol, acidified by polyethyleneglycol as well as their ethylene oxide condensation products and arylalkyl polyether alcohols.

Another class of compounds used as emulsifiers or emulsion stabilizers are gum and proteins such as gum arabic, soybean protein, sodium alginate. Ammonium caseinate has also been used as an emulsifier with success.

Ammonium salts or other water-soluble or water-dispersible salts can also be used Salts of alkyd resins with a high acid number can be used, such as those available for example are by adding sodium hydroxide to condensation products of maleic acid and glycerine, modified phthalic anhydride-glycerol-fatty acid condensation products with high acid number, esters of polyhydric alcohols of terpene-maleic acid condensation products, thus, in general, any suitable wetting or emulsifying agent can be used.

Any cellulose fiber material, the positively charged melamine-aldehyde condensation products can absorb from their aqueous dispersions, can be coated by the present process or impregnate. One can use a large number of the cellulosic fiber materials used in the manufacture of Paper, cardboard or as fillers for molding compounds are used, such as kraft pulp, rag pulp, Use soda, sulfate, sulfite, and alpha cellulose pulp. Other forms of cellulosic fiber materials as well come into consideration, such as hydrated cotton winters. These materials can be used alone or in a mixture with fibers of other origins, such as jute, hemp, sisal, asbestos fibers, glass fibers and other cellulosic cells or not Cellulose-containing materials are used, which reduces the notch toughness and the mechanical Strength or other properties of the molded or pressed impregnated materials can be improved. Typical products made according to the present process What can be improved are water- and steam-resistant papers, paper or cardboard containers or cartons for milk, butter or food, resin-impregnated laminated paper, Abrasives consisting of resin-impregnated paper coated with abrasive particles, Pressed articles, pre-pressed articles, electrical insulators, filter paper, heat insulating Paper or loose masses of unfelted and unpressed paper stock, such as those used for air filters, Dust filters or thermal insulation can be used.

When carrying out the method according to the invention, the cellulose fiber material is preferably used first suspended in water, where it can be whipped for a shorter or longer period of time, to hydrate the cellulose and then into a Jordan device or similar machine brought in. Any ratio of cellulosic material to water can be maintained will; however, a paper stock concentration of about 0.5 to 6% was preferably used. The positively charged melamine-aldehyde condensation product is then added, preferably in the form of an aqueous dispersion of about 5 to 15% dry matter, whereupon the Fiber suspension is left to stand for 15 minutes to 3 to 4 hours and longer. This letting go is not an essential stage as the adsorption of positively charged melamine resin by the Paper pulp takes place very quickly, but the behavior in the subsequent treatment of the impregnated This greatly improves the fiber mass on the paper machine.

After pre-treating the cellulose fiber !! with the positively charged melamine resin becomes the impregnating agent in the form of an aqueous suspension, preferably one with relatively less Particle size, introduced. The flocculation effect of the positively charged melamine-aldehyde condensate does not depend on the particle size of the impregnating agent added; but it will be one more uniform covering of the fibers and better behavior of the impregnated fiber materials Achieved on the paper machine when a small particle size dispersion is used will. Aqueous dispersions with an average particle size of 1 to 2 microns or fewer have shown excellent results in practice, and therefore the addition of the impregnating agent is necessary recommended in the form of an aqueous dispersion with this particle size. The flocculation of the impregnating agent and its adsorption by the positively charged resin treated cellulose fiber goes on fairly quickly, and the rest time of the mixture after addition of the impregnating agent produces only very small differences in the result. The substance can therefore Formed immediately after the addition of the impregnating agent or possibly significantly later will.-

The optimal amounts of colloidal melamine resin necessary for the best adsorption of a dispersed or emulsified impregnating agent will change with nature and particle size the dispersion, the nature of the positively charged resin, the duration of contact between the Fibers and the colloidal melamine resin, with the Pn value of the paper stock and other factors. Because of the properties of the dispersed material added and because of the requirements that to be placed on the finished sheet or on the object, it may also be desirable to increase the amount of

Modify melamine resin to improve properties of the finished products. The required amount of melamine resin can generally between small amounts, approximately on the order of 0.1% of the weight of the paper stock, up to several times the weight of the impregnating agent vary. If you use relatively large amounts of impregnating agent of about 50 to 100% or more, calculated on the weight of the cellulose fibers, the optimal amount of positively charged resin is between about 2 to 15%. When using smaller amounts of impregnating agent, e.g. 5 to 50% of the cellulose weight need larger amounts of positively charged resin, ζ. B. 5 to 30% for use come. Larger amounts of colloidal melamine resin, up to ioo%> or more, based on the weight of the impregnating agent, can be added to optionally improve the properties of the modify finished product; but in such cases there is a marked decline in the Adsorption of the impregnation agent and an increase in the drainage time of the fabric watch. As a rule, it is advisable to disperse the impregnating agents to be added Carry out samples under the desired operating conditions before finally deciding on the ones to be used precise amounts of positively charged melamine resin is decided. Still with relatives of positively charged melamiti-aldehyde condensation products only a high degree of flocculation and adsorption of the added coating or impregnating agent is achieved, it is Occasionally it is advantageous to add an additional detergent during the preparation of the paper. For example, "often gets better Water drainage from the fabric on the papermaker's screen achieved when small amounts Alum on the order of 0.5 to 3% based on the weight of the cellulosic material is added will. The alum or other precipitant is almost always added after the other ingredients have been mixed, otherwise there is a risk that the colloidal, positively charged melamine resin is coagulated or precipitated. However, in particular Cases where prior coagulation of excess melamine resin may be desirable, ' the alum or some other electrolyte self- |

be understandable introduced before the addition of the impregnating \.

The invention can be applied in a wide variety of fields: in papermaking,

• when pre-pressing, laminating, pressing, pre-forming and are generally used wherever cellulose fiber material with thermoplastic, thermosetting, waxy, bituminous or other binding, impregnating or coating agents is intimately combined. Subsequent Examples should explain the possible uses:

Paper and cardboard production: As mentioned above, the method can \ serve to achieve more uniform deposition of large amounts waxes, bituminöseroder similar substances than usual before sheet formation in paper stock. If ink resistance, water resistance or similar effects are to be achieved, these binders are used in relatively small amounts of about 1 to 5% or, if necessary, of use

! of asphalt, up to 10%, based on the dry

: weight of the paper stock, applied. The dispersion of the positively charged melamine-aldehyde condensate is first in the Hollander with the aqueous suspension of any desired concentration, z. B. mixed with a 0.5 to 5% pulp suspension and allowed to stand for V2 to 3 hours, whereupon the binder is added in the form of an aqueous dispersion. Flocculation of the dispersed binder by the positively charged melamine resin occurs quickly, and the particles of the same, intimately mixed with the particles of the colloidal melamine resin, are evenly retained by the paper stock. The treated fabric is then allowed to run onto the wire or cylinder of the paper machine and the paper obtained is passed through heated rollers in the usual manner. In this way, wallcoverings, insulating cardboard and heavy pulp for paper containers can be made.

Lightweight papers with improved tear strength, water resistance and other desired Properties can be achieved by incorporating dispersions of rubber, polyacrylates and elastomers and various copolymers can be obtained by the process described. the Properties of the sheets can be determined by heating, wet or dry pressing, calendering, hot calendering, Friction calenders, lamination with metal foils or similar processes modified will. The paper can also be dried on polished metal cylinders. For the present Processes can use more expensive or cheaper pulps, such as wood pulp, waste fibers, and products with short Fibers, can be used, always obtaining good properties for sheet making. Manufacture of high resin paper: paper made with large quantities of thermoplastic or thermosetting resins such as polystyrene, polyethyl acrylate, modified or unmodified Phenol-formaldehyde resins or similar resins can be used for a wide variety of applications Purposes such as lamination by means of heat and pressure, for the production of electrical insulators and capacitors', for pressing cardboard, etc. quantities of binders from 5% to considerably more than the weight of the cellulosic fiber material, according to be incorporated in the following procedure:

A cellulosic fiber material such as kraft pulp is preferably hydrated by conventional heating to a slightly lower temperature than in the ordinary papermaking process. Of the Paper stock is then diluted with water to a dry matter content of about 1 to 6%, whereupon a colloidal solution of positively charged metal

amine-aldehyde condensate in an amount of about 2 to 15Ύ0 of the amount to be introduced into the paper stock resinous binder is added. After mixing, the suspension becomes preferably left to stand for a short time, followed by an emulsion or dispersion of the desired Resins is added with stirring. The fabric is then formed into paper or paperboard, or he can be made by any suitable pulp deforming process are processed.

In some cases it may be desirable to remove the fiber suspension after adding the solution positively charged melamine resin, but before the introduction of the resin emulsion an alkali such as sodium or add ammonium hydroxide. Alum can also be added to regulate the pH value, Elimination of foam and stickiness and modification of the water removal properties of the substance.

Paper or cardboard with a content of resins, pitches or waxes of 5 to 75%, based on the weight of the finished sheet, can be considered for different purposes, for which paper is commonly used. s5 But they show increased strength against tearing, Water, steam, fat, expansion and shrinking under the influence of varying humidity conditions. In some cases it will be full Development of these properties through mechanical treatments such as drying at high temperatures Temperatures, cold or hot calendering reached. Paperboard produced according to the invention result Paper cardboard and containers that provide improved protection and their production costs by using dispersions or emulsions of cheap, resinous materials inside manageable limits can be kept. Wall coverings and papers for building purposes, insulating cardboard, Floor or roof coverings can also be made by the same process.

Wax or oil papers can be made into large amounts of amorphous or crystalline Waxes or mineral or vegetable oils in the form of their emulsions or dispersions to win. Heating or hot calendering is generally required to achieve the maximum To achieve transparency and water resistance. Strong and flexible papers with single> or fabric-like properties can be created by incorporating synthetic or natural latex, elastomers and resins in suitable amounts. Heating, calendering and others mechanical processes are able to improve the desired properties. It can also by introducing substances such as chlorinated waxes or polymers of chlorinated styrene or various thermosetting resins, fire and flame retardant papers and cardboards will. Mineral fibers and fillers can also be incorporated at the same time in order to achieve a To achieve maximum fire resistance.

Preforming and pressing: cellulose fiber materials, such as paper pulp, which according to the invention are impregnated with resin binders, are important Commercial products because they are dehydrated and pressed in this or easily into compact masses State can be sold. These masses can be preformed by suitable pressing processes and the resulting preforms are then used, or they can, for hot pressing processes chopped, shredded or ground (in a dry or moist state) and then alone or mixed with other molding powders, molded by compression molding or injection molding will. When rubber latex or other forms of natural or synthetic rubber are in are applied to the fibers in the manner described above, the products obtained can be on hot rollers are processed, with other fillers, such as finely divided carbon black or zinc oxide, along with cure accelerators such as mercaptobenzothiazole and antioxidants, and the product optionally can be hardened as usual by heating in molds.

In the manufacture of large objects of irregular shape from molding compounds containing a resin binder and contain a cellulosic filler, it has proven very difficult in all Divide the mold to get even distribution and even flow. To this difficulty to bridge, a process for preforming or prepressing was developed, with a Uniform mixture of resin binder and filler approximately that required for the end product Shape is given without curing the resin. The present process is for preforming processes this type is particularly suitable as the fiber character of the filler is retained and therefore the preforming can be done by wet pressing methods. Moreover, the loss is on Resin in the flue water is much less when working according to the present invention.

By preforms, which with the help of dispersions of positively charged melamine-aldehyde condensates many pressing problems have been greatly simplified, and they have increased the number of kinds of fillers and resins that can be molded. Wood flour, cotton flakes, kraft pulp and other cellulosic materials can be used come, as well as schnitzels of cellulose tissue, canvas, string and other fillers, whereby increased toughness and notch toughness are imparted to the pressed pieces. Any fillers or Mixtures of these can be suspended in water with the solution of the positively charged melamine-aldehyde condensate and then treated with thermosetting or thermoplastic resin binders in the be impregnated evenly as described above, after which they are placed on a sieve or another permeable surface, which have the desired shape, can be preformed. The losses the resin dissolved or suspended in the sewage is usually less than 25%, and also these small amounts can even be

use of water can easily be used. In this process are advantageous phenolic and Cresol-formaldehyde condensates in amounts of ίο to ιoo%, calculated on the dry weight of the Cellulose fibers. However, other resins, such as those in the examples below, can also be used are described. Laniinieren and pressing: According to the invention with large quantities of thermoplastic or thermosetting resin impregnated sheets and cardboard are suitable is particularly suitable for laminating and pressing processes because of the even distribution of the resin material. The lamination of paper is preferably carried out on an ordinary Fourdrinier machine or done on a roller machine. Heavier cardboard for pressing purposes is often used on a so-called Xass machine, d. H. made on a papermaker's cylinder that comes with a drum is connected, on which the wet sheet can be wound up until a cardboard of the desired Thickness is obtained. When thermosetting resins are used, a curing catalyst, how phthalic acid or oxalic acid are sprinkled on the wet paper before it is dried, or in the case of using phenol-formaldehyde resins, hexamethylenetetramine can be added the dried paper or paperboard are applied. Laminating will be like this carried out that a stack of the impregnated sheets is pressed between hot plates. The pressing takes place either directly from the paper or the cardboard, which is as preforms or only after the matted fiber material has been shredded or chopped up is to achieve better flow in shape. In this process, moldings of high mechanical strength and high notch toughness.

These processes mentioned for the further processing of the cellulose fiber materials impregnated according to the process are not claimed as such here.

The invention is to be explained in more detail by the following examples.

H e i s ρ i e 1 ι

100% suspensions are made from dry, bleached kraft pulp. The following additions are made to samples of 100 cm ³ each of the suspensions: A. none; B. 10% colloidal melamine-formaldehyde resin calculated on the dry weight of the paper stock; C. 100% polystyrene obtained by emulsion polymerization, calculated on the dry weight of the paper stock; D. 100% colloidal melamine-formaldehyde resin with stirring and then 100% of the polystyrene dispersion.

From 1000 cm ³ of each of the samples treated in this way, sheets were produced by hand by filtering through a 150-mesh copper sieve on a Buchner funnel. The filtrate was passed through the residue twice. The volume of the filtrate was then measured and the dry content determined. The leaves were dried, weighed and the total nitrogen content determined therein.

The results are compiled in the table below, with the numbers indicating the weight specify in grams:

Fibers') Added Fabrics Total Dry
content of
Sewage Found Fabrics Melamine-
resin
in sheet ² ) sample 6th Melamine-
resin Polystyrene
1 6th 0.08 Dry
sheet Total _ Λ 6th _ 6.6 0.33 6.19 6.27 0.25 B. 6th 0.6 - 12.0 6.08 6.82 7.15 - C. 6th - 6th 12.6 0.25 6.70 12.78 o, 53 I) 0.6 6th 13.52 13.77

') about

² ) Determined according to Kjeldahl's nitrogen analysis

The results clearly show the increased adsorption of polystyrene and positively charged melamine-formaldehyde resin, which is achieved when both resins are used together. The paper stock that was not treated with melamine resin lasted only negligibly Amount of styrene back, despite filtering the waste water twice. It just lasted about 40% of the added colloidal melamine resin back, if polystyrene was not used. In contrast, almost all of the polystyrene (at least 95%) and almost 90% of the melamine resin in the Prol> e D paper.

The polystyrene used here and in other examples was made as follows:

ICs were 1.2 parts by weight of sodium laurel sulfide

fonat dissolved in 58.8 parts by weight of water at 94 ° and 0.05 part by weight of 40 volumes of hydrogen peroxide was added to the solution. 40 parts by weight of styrene were uniformly introduced into the solution over the course of 1 ½ _{9 hours.} The exothermic polymerization reaction developed slowly and was over after three and a half hours. Steam was then passed through the alasse to remove unpolymerized product and the dispersion adjusted to a dry content of 25%.

B e i s ρ i e 1 2

This created a colloidal dispersion of positively charged melamine-formaldehyde condensate produced that a dried by atomization

Nice condensation product from about 3 moles of aqueous Formaldehyde solution and 1 mol of melamine in warm water, the 0.8 mol of HCl for each one mol Alelamin contained, dissolved to a 12% solution and allowed to age for about 16 hours.

Bleached Kraft pulp was soaked in water for half an hour, ^{kept in circulation for about 1} hour in a laboratory dutchman with a content of 2,500 kg, beaten for half an hour with a full load (14 kg), refined for 2 minutes in a Jordan apparatus and then on one Concentration set at 1.2%.

In addition, emulsion polymerization as described in Example 1 produced a dispersion of polyethyl acrylate with a resin content of 25% and an average particle size made of less than a micron.

The paper stock suspension was first mixed with 3% colloidal melamine-formaldehyde resin, calculated on the dry fiber weight, and stirred for 30 minutes. The ρκ value was then adjusted to about 6 to 7 by adding sodium or ammonium hydroxide, and the polyethyl acrylate emulsion was added. The mixture was then stirred for 30 minutes and formed into sheets on a Valley handsheet machine having a 60 mesh screen. The leaves were then dried with absorbent felts from the wire removed and without pressure on a drying drum for about 10 minutes at 100 to 120 ^0th

The adsorption of the acrylate emulsion was determined by examining the waste water, and it it has been found that the melamine resin is very good at uniform deposition and adsorption of the polyethyl acrylate emulsion causes. Indeed, in all cases the adsorption was practically complete. In In the table below, the numbers in the column headed by% acrylate mean the Percentage of dry polyethyl acrylate that was added to the fiber suspension and that affects the Relate dry weight of paper fibers:

Trains sheet sewage Weight in Attempt no. put it
Acrylate
in% education
(relative) clear kg per 500
sheet of paper
62.5 X 100 ι (blind) ') Well cloudy 66,490 2 (control) ² ) 5 - very cloudy 66,490 3 IO - clear 66,490 4th O - - - · 5 5 - - 72,930 6th IO - - 75,650 7th 20th - slightly cloudy 8l, 995 8th SO - 89.240

¹ ) Without the addition of melamine or acrylate resin

² ) Without the addition of melamine resin

The results show that a good adsorption of polyethyl acrylate is achieved by the paper pulp becomes even when using large amounts.

Example 3

Bleached kraft pulp was soaked a ⁱ lt hour in water, held for ¹ Ii hour in a laboratory Dutch in circulation, beaten ¹ It hour at full charge, refined then 2 minutes and o brought with water to a concentration of 1.2 ° /. Colloidal melamine-formaldehyde resin was then added in an amount which was equal to the dry weight of the fiber, in the form of a 12% solution containing 0.8 mol of HCl per 1 mol of melamine. The mixture was stirred for 30 minutes. The pulp was then filtered and washed with large amounts of water to remove any melamine resin that had not been adsorbed by the fibers.

The impregnated pulp was resuspended in water at a concentration of 1%, whereby the pH was 6.3. A portion of the suspension was formed into a sheet which, as per Analysis found to contain 1.1% melamine resin. Another part was with 100% polystyrene dispersion, calculated on the dry weight of the paper pulp. Leaves were then formed. The same amount of polystyrene emulsion was added to another i% slurry of given the same paper pulp which had not been pretreated with melamine resin, and it was leaves are also formed from this mass.

More than 80% polystyrene was retained by the melamine resin pretreated pulp and was evenly distributed in the finished sheet. The untreated pulp sheet contained little or less no polystyrene.

This example shows that the precipitation effect of the colloidal melamine-aldehyde resin even remains after the resin has been adsorbed by the fiber material. Cellulose pulp and other fiber materials that have been pretreated with melamine resin can thus act as flocculants for emulsions or dispersions of waxes, rubber, resins and other similar Substances are used.

Example 4

A 12% solution of colloidal methylamine-formaldehyde condensate, which contained 5 g, was diluted with water to 2 l and added to the solution with stirring 200 g of an aqueous emulsion, which contained 50 g of polystyrene. The polystyrene was immediately flocculated and the resulting precipitate separated from the liquid by filtration. The filtrate was clear which shows that precipitation was complete was achieved.

The precipitated resin was dried, ground, and a part thereof was pressed at 155 ⁰ and at a pressure of 260 kg per cm ^2, wherein a clear compact was obtained.

The nitrogen content was determined in a sample of the resins and, from this, the content of melamine resin of 6.75 per cent.

The procedure described above was carried out using 25 g of melamine resin and 25 g of poly

styrene and neutralization with ammonia repeated before filtration. It became clear again Get the filtrate. The precipitate contained 46% melamine-formaldehyde resin.

This example shows the undocking effect of the colloidal solution of positively charged Melamine-aldehyde condensate in the absence of cellulosic fiber material and the importance of its presence an excess of colloidal melamine resin in the system over that produced by the Cellulose fibers adsorbed amount of the resin.

Example 5

80 parts by weight of dry bleached kraft pulp were mixed with water to form a 100% suspension mixed, and there were 168 parts by weight of a 12% colloidal, positively charged suspension Solution of melamine-formaldehyde resin (20% calculated on the dry weight of the paper stock) added and stirred for 10 minutes. The pH of the slurry was adjusted to 4.0, and it became 160 parts by weight of a polystyrene emulsion with a particle size of about 5 microns added and the mixture stirred for 10 minutes, whereupon it is diluted to a 0.6% strength paper pulp and formed into leaves. The waste water was clear indicating that all of the polystyrene was from the stock was withheld.

The leaves were shredded mechanically, filled at 155 ⁰ in a mold and pressed for 5 minutes at this temperature. A well-shaped piece of good mechanical strength and appearance was obtained.

A second sample of kraft pulp was impregnated with 20% λlelamiπ-formaldehyde resin and 200% polystyrene resin by the method described above, with the exception that the pn value of the pulp containing the melamine resin was adjusted to 7 prior to the addition of the polystyrene dispersion , 0 was increased. The impregnated pulp was formed into a sheet 0.625 cm thick on a Buchner funnel and dried ^{for 93 seconds.} From the middle

A disk was cut out of this sheet and placed in a disk mold at 155 °. After the few minutes of heating required for preforming, the mold was closed and a pressure of 260 kg / cm ^{2 was applied} for 5 minutes. The preform took the shape of the mold and a well-shaped piece of good appearance resulted.

Example 6

A solution of 200 g of a condensation product from tert. Butylphenol and formaldehyde in 300 g of methylcyclohexanone was at 93 ° with 400 g of water, the 2.5 g of sodium dioctyl sulfosuccinate and 10 g of a sorbitol monopalmitate-ethylene oxide condensation product contained, mixed. The mixture became an emulsion with an average particle size of 1 to 2 microns homogenized. The dry content, which was determined by heating a sample to 105 ° to constant weight, was 23.8%.

Bleached kraft pulp was impregnated with the phenol-formaldehyde resin solution according to the following process: The paper stock was diluted with water to a fiber content of 1%, mixed with colloidal melamine-aldehyde resin solution and stirred for 5 minutes. The pH was adjusted to the desired value by adding sodium hydroxide or hydrochloric acid. The phenol-formaldehyde resin emulsion was then added and stirring was continued for 5 minutes, after which the impregnated fibers were formed into sheets. These sheets were pressed between absorbent felt and dried on a drying drum and then heated at 100 to 120 ° it, for 1 hour at 260 ^0th

Different amounts of phenol-formaldehyde resin and melamine-formaldehyde resin were used brought into the paper stock in this way and then determined the resin uptake. The amounts used and the results obtained are summarized in the following table:

■ * Fiber ¹ J resin in ° / " melamine Ph
the pulp rilattaicke
in mm Middle resin No. of dry fibers 5 Sheet weight recording o, 5 phenol 5 7th 0.25 in g in% ² ) A ι 1.0 50 5 7th O, ₄ 25 0.60 Φ
31 A 2 2.0 50 5 7th 0.775 1.29 53 A3 3, o 50 10 7th 1.150 2.70 64 A ₄ 0.5 50 IO 7th 0.250 4.34 8i B ι 1.0 100 IO 7th o, ₄ 5o 0.75 45 B 2 2.0 100 IO 7th 0.800 I, 6l 56 B3 3, o 100 15th 7th 1.225 3.36 62 B ₄ 0.5 100 15th 7th 0.300 5.38 72 C ι 1.0 150 15th 7th o, 55o 0.94 53 C 2 2.0 150 15th 7th 1.050 2.00 61 C ₃ 3, o 150 20th 7th 1,575 4.30 70 C ₄ 0.5 150 20th 7th 0.300 6.91 79 D ι 1.0 200 20th 7th 0.625 1.01 46 D ₂ 2.0 200 20th 7th 1.225 2.38 63 D ₃ 3, o 200 7th !, 75O ' 5.22 73 D ₄ 200 . 6.92 90

'), ² ) see notes at the end of the table.

Claims (5)

No. ί Fiber ¹ ) Resin in%
of dry fibers 15th O Ph
the pulp Sheet thickness
in mm Middle
Sheet weight resin
recording Blind I Phenol melamine 15th in g in ¹ Vo ² > egg try | 0.5 150 15th 4th 0.225 0.62 14th E2 ι 1.0 150 15th 4th 0.425 1.37 22nd E3 2.0 150 15th 4th 0.800 2.89 27 E ₄ 3.0 150 15th 4th 1.225 4.63 33 F ι 0.5 150 15th 5 0.250 0.82 39 F 2 I, O 150 15th 5 0.550 1.86 52 F3 2.0 150 15th 5 1.025 3.99 60 F ₄ 3.0 150 150 15 5 1.525 6.55 72 Gi 0.5 150 150 15 6th 0.275 0.88 46 G2 1.0 150 15 6th 0.55 ° 1.97 59 G3 2.0 O O 6th 1.075 4.27 69 G ₄ 3.0 O O 6th 1,500 6.76 76 0.5. O O 7th 0.225 o, 53 - 1.0 O 7th 0.400 1.05 - 2.0 7th 0.650 2.06 - 3.0 7th 0.875 3.16 - ^! ) Number of grams of dry fibers in suspension that are used to hold the sheet. ² ) Sheet Weight - Fiber Ξ. loo Weight of the added resin These results show that there is a high degree of adsorption of thermosetting resins of the type Phenol-formaldehyde condensate is achieved when using colloidal melamine-aldehyde resin solutions. Other phenol-formaldehyde condensation products, such as those from phenol itself, mixtures of phenol and cresols, and mixtures of phenol, cresol and xylenols, can also be used. Modified phenolic resins can also be applied to cellulose fibers in this way, so ■ / .. B. Condensation products from mixtures of phenols and aminotriazines. like melamine, with formaldehyde or other reactive aldehydes. Any of these resins can be emulsified and incorporated in an aqueous suspension of a filler such as paper stock by the method described above. The impregnated filler obtained is well suited for pulp-press processes. Example 7 Following the procedure described in the previous example with phenol-formaldehyde resin impregnated sheets were pressed into laminated paperboard. A 100% aqueous suspension of bleached kraft pulp was made with 20% colloidal melamine-formaldehyde resin and then impregnated with 200% phenolic resin, based on the dry weight of the paper fibers. The received The impregnated fabric was processed into sheets of 15 x 15 cm on a hand sheet machine. The wet sheets were pressed between absorbent felts on a drying drum dried at 100 to 120 ° and then in one Oven heated to 160 ° for ι hour. The dry leaves contained about 60 to 70% by volume of resin. The lamination was carried out by laying three to six sheets on top of one another and pressing between 15 cm thick plates of non-oxidizing steel under a pressure of 210 kg / cm ² at 160 ° for 10 minutes and letting them cool under pressure. The laminates obtained had considerable rigidity and uniform transparency, indicating an even distribution of the tar. P A T E N T A .N S i> R C C H E: i. Process for applying or introducing water-insoluble coating or impregnating agents on or in cellulose fiber materials, characterized in that the fibers suspended in water, the aqueous fiber suspension an aqueous dispersion of the coating or adding impregnating agent in a flake-free state and said agent in the presence of the suspended fibers by means of a colloidal dispersion of positively charged Melamine-aldehyde condensate flocculates and that you then optionally the so coated or impregnated cellulose fiber material with removal of the suspension water into a matted Product transferred, with flocculated, but not adsorbed, suspended in water Coating or impregnating agent is deposited in the matted product. 2. The method according to claim 1, characterized in that that the aqueous fiber suspension is first a colloidal dispersion of the positively charged melamine-aldehyde condensate and then adding an aqueous dispersion of the coating or impregnating agent. 3. The method according to claim 1 and 2, characterized in that the aqueous Fiber suspension after the addition of the colloidal len dispersion of positively charged melamine-aldehyde candensate preferably at least 30 minutes under non-alkaline conditions before the addition of the dispersion of the Coating or impregnating agent takes place. 4. The method according to claim 1 and 3, characterized characterized in that the aqueous fiber suspension at a pn value of about 3 to 6 lets stand before the addition of the impregnating agent takes place. 5. The method according to claim 1 to 4, characterized in that the dispersion of the Coating or impregnating agent adds an anionic or nonionic emulsifier. 6. The method according to claim 1 to 5, characterized in that one aqueous fiber suspensions used at a concentration of 0.5 to 6%. 7. The method according to claim 1 to 6, characterized in that one aqueous fiber suspensions with 2 to 30%, preferably 2 to 15% of the positively charged melamine-aldehyde condensate, calculated on the weight of the coating or impregnating agent. 8. The method according to claim 1 to 7, characterized in that the aqueous fiber suspension with at least 5%, optionally 50 to 100% coating or impregnating agent, based on the dry weight of the fibers. 9. The method according to claim 1 to 8, characterized in that as a coating or Impregnating agent polystyrene used. 5267 7.