CS273137B1 - Method of paper sizing agents production - Google Patents

Abstract

This method of production of paper sizing agents is based on the dissolving of resin in 2 to 30 mass parts of organic solvents from the group of methylene chloride, 1,2-dichlorpropane, ethanol, propanol and isopropanol at 15 to 80 degrees C and the solution disperses at 20 to 95 degrees C and pressure of 100 to 300 kPa with 60 to 20 mass parts water containing 1 to 10 mass parts of tensides and/or protective colloids, whereupon the organic solvent is removed by distillation at 30 to 90 degrees C and pressure of 6 to 50 kPa and the occurring dispersion is cooled under 25 degrees C, which is possible supplemented with water to produce a dispersion with a dry matter content of 30 to 50 % by weight.

Description

SUMMARY OF THE INVENTION The present invention provides a process for preparing paper sizing based on aqueous dispersions of a mixture of polymeric carboxylic acids with resin acids. They can be applied especially when sizing paper in the mass, but also for surface sizing.

In the paper industry, sizing agents based on natural and synthetic substances are used (V. Hněvkovský et al.: Papermill Handbook. Prague, SNTL 1983). Natural sizing agents are traditionally represented by waxes, starches, proteins, especially rosin and its derivatives (German Patent No. '1 467 545, US Patent Nos. 3,400,117, 3,565,755, 3,817,768, British Patent Nos. 1,026,945 ). More recently, synthetic sizing agents include, in particular, aldoketene dimers (U.S. Patent No. 2,848,194, U.S. Patent No. 4,243,481, 4,382,129), hydrocarbon resins (U.S. Patent No. 226,224, Japanese Patent No. 8,100,399, NSR). U.S. Patent No. 2,434,216, U.S. Patent No. 3,953,407) and other high molecular weight compounds. Said sizing agents come in the form of aqueous solutions or pastes of their soaps and mainly as aqueous dispersions, optionally also as dry products. They are used for sizing paper cells in matter (internal sizing) or its surface (surface sizing). Sizing the paper achieves its resistance to the penetration of liquids, especially water and ink. However, the most commonly used rosin is not available worldwide in sufficient quantities, and its composition and purity vary considerably by provenance. Synthetic sizing agents do not have these advantages and can be used to prepare precisely defined products. They are often applicable only to a particular sizing method of some special paper types. Their synthesis, e.g. dimers is very difficult and expensive. Many high molecular weight substances have only a low sizing effect and are more suitable as binders for papermaking coatings.

In known procedures, such as those disclosed in U.S. Pat. No. 1,131,348, U.S. Pat

6, 3,966,654, 4,199,396 and 4,203,776, the rosin melts at 200 ° C or higher and disperses at temperatures above 100-180 ° C and thus at high pressures. Even higher temperatures are required when using synthetic resins with higher softening points. Furthermore, you can mention several MS. author's certificates that deal with sizing, eg MS. No. 242,203 protects a process for the preparation of an older type of sizing wherein the principle is to convert hydrophilic carboxylic acids into the form of water-soluble salts of alkali or nitrogen bases using homogenization in the presence of hydrocarbons or a mixture of hydrocarbons remaining in the sizing and paper cause unpleasant odor, which is a certain disadvantage of MS. author's certificate No. 242 203. According to MS. No. 256,868, the melt-resin mixture is also converted by alkali into water-soluble salts, which are then converted by intensive dispersion and high-pressure homogenization to the final sizing form. Cited dispersion and high-pressure homogenization is also the subject of another MS. No. 256,867, wherein the resin mixture is then converted into a fine dispersion having a higher sizing efficiency with the addition of surfactants and protective colloids. The disadvantages of these processes are primarily the use of high temperatures and pressures.

The aforementioned disadvantages are overcome by the present invention, which relates to a process for the manufacture of paper sizing based on aqueous dispersions of natural and synthetic resins and additives of 20 to 40% by weight. parts of a mixture of polymeric carboxylic acids having an average molecular weight Mn of 500 to 20,000 and a content of 45 to 125 g of C00H / 1000 g with resin acids and / or derivatives thereof, in particular with adducts of? 6? -unsaturated carboxylic acids having 3 to 6 carboxylic acids atoms or their anhydrides having a softening point of 50 to 120 ° C and a content of 40 to 180 g of CO 3 H / 1000 g, in a weight ratio of 0.95: 0.05 to 0.05: 0.95. The process according to the invention consists in dissolving the resin mixture in 2 to 30 wt. parts of organic solvents from the group of methylene chloride, 1,2-dichloropropane, ethanol, propanol and isopropanol at a temperature of 15 to 80 ° C and the solution is dispersed at temperatures of 20 to 95 ° C and pressures of 100 to 300 kPa with 60 to 20 wt. parts of water containing 1 to 10 wt. parts of surfactants and / or protective colloids, whereupon the organic solvent is removed by distillation at a temperature of 30 to 90 ° C and a pressure of 6 to 50 kPa and the resulting dispersion is cooled below 25 ° C and optionally topped up with water to form a solids dispersion 30 % to 50 wt.

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CS 273137 Bl

The preparation of sizing agents according to the present invention has some advantages over the known production processes, first of all the work at substantially lower temperatures and almost without pressure. This simplifies the demands on production equipment and energy requirements. They can be produced over a very wide range of polymeric carboxylic acid compositions, resin acids and / or derivatives thereof. The process involves reducing the thermal stress of the resins and facilitating handling. Aqueous dispersions of mixtures of these sizing agents are very stable chemically and mechanically. They do not tend to coagulate when diluted with hard water. The average particle size of the dispersion is below 1 µm and exhibits a high sizing effect. Sizing particles occupy a larger surface area of the papermaking fibers in a thin layer, thereby achieving considerable savings in sizing, suitable for surface and interior sizing of almost all paper, cardboard and paperboard.

The new invention describes the preparation of modern types of high performance sizing agents in the form of fine dispersions of the active resin component in water having a particle size of up to 1 µm. The advantage of this new type of sizing is mainly that for the same degree of sizing, several times lower amount of sizing is sufficient, moreover new types of sizing do not have a strongly alkaline reaction and therefore the paper is sizing in a much more gentle way than mentioned in Czech. Author's certificate No. 242 203. Another significant difference against MS. No. 242,203 is that solvents are removed from the sizing agent by distillation and do not remain therein until further processing. This is of undeniable ecological importance precisely during glueing, when the working environment is not contaminated and the produced glue paper does not smell of hydrocarbons. This is because volatile solvents are easily removed.

According to the invention, the main constituent of the paper sizing comprises mixtures of polymeric carboxylic acids, resin acids and / or derivatives thereof. Polymeric carboxylic acids include, in particular, copolymers of> 4,? - unsaturated carboxylic acids having 3 to 6 carbon atoms or their anhydrides or their adducts with unsaturated polymers. Unsaturated acids are represented by acrylic, methacrylic, maleic, fumaric, citraconic, pyrocinchonic, mesaconic and itaconic acids. Of the anhydrides, maleic anhydride is the most important. their comonomers are predominantly monoolefins (eg ethylene, propylene, butenes, ptentenes, hexenes, heptenes, styrene, vinyl spheres, vinyl ethers, vinyl halides, cyclopentenes, cyclohexenes, indenes, coumarone) and diolefins (butadiene, isoprone, piperylene, dimethylbutadiene) chloroprene, pentadiene, hexadiene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, etc.). For copolymerization with saturated acids or their anhydrides, either individual monomers with one or two double bonds or different mixtures thereof can be used. Instead of the comonomers mentioned, liquid oligomers, co-oligomers or low-molecular homopolymers and copolymers containing double bonds may be used for copolymerization or addition. Suitably the polymeric carboxylic acids have an average molecular weight of 500 to 20,000 and a content of 45 to 125 g COOH (1000 g)

The resin acids used are mainly rosin obtained from wood, balsamic resin and crude tall oil. Their essence is mainly unsaturated abietic and levopimaric acid, then neoabietic, dehydroabietic, hydroabietic, palustric, dextropimaric and isodextropimaric. Technically important resin acid derivatives include, in particular, their adducts with the abovementioned 1H-unsaturated carboxylic acids or their anhydrides, in particular with maleic anhydride. Further suitable are reaction products with formaldehyde, hydrogenated and polymerized resin acids. Products having a softening point of 50 to 120 ° C and a content of 40 to 180 g COOH / l · 000 g are used. They are combined with polymeric carboxylic acids in a weight ratio of 0.05 with 0.95 to 0.95: 0.05.

As solvents for the preparation of solutions of mixtures of polymeric carboxylic acids, resin acids and / or derivatives thereof, chlorinated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloropropane, but also polar solvents such as ethanol, butanol, propanol, isopropanol can be used. Preferably, more volatile methylene chloride is used to facilitate removal from the finished dispersion. Mixtures of the above solvent groups are also preferred.

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The solutions of the described mixtures of polymeric carboxylic acids, resin acids and / or derivatives thereof are dispersed in water in the presence of surfactants and / or protective colloids · Usually water softened, demineralized or deionized is used. Its content in the sizing dispersion ranges from 500 to 1000% by weight. Suitable are ionic and non-ionic surfactants or mixtures thereof. Suitable ionic surfactants are, in particular, the alkali salts of higher acyclic, resinous and polymeric carboxylic acids, alkylsulfonates, alkylpolyethylene glycol ether sulfates, alkylarenesulfonates, alkylphosphates, alkylpolyethylene glycol ether phosphates, alkali metal salts of fluorinated alkylcarboxylic and alkylsulfonic acids, and ammonium salts. sulfonium, phosphonium and other compounds. Non-ionic types include polyethoxylated higher acyclic carboxylic acids, their amides and esters, higher acyclic alcohols, especially alkylphenols. Protective colloids are represented by water-soluble compounds such as cellulose ethers (methylcellulose, hydroxyethylcellulose, carboxyethylcellulose), alkali salts of polymers of acrylic or methacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone, as well as alginates, gelatin, starch and proteins. Surfactants and protective colloids may be added to the sizing dispersions individually or together in an amount of 0.1 to 10% by weight.

Up to 25 wt. parts of other various ingredients. These are, in particular, below average wax sizes (beeswax, carnanbine, montan, ozokerite, ceresin, paraffin), proteinaceous (casein, gelatin, soy protein), starch (starch, dextrin, oxidized, hydroxyethylated and cationic starch) and cellulosic (the above mentioned) derivatives and cellulose). Synthetic sizing agents are represented by aldoketene dimers (mainly tetradecylketene and hexadecylketene) and some synthetic polymers. Other additives include antifoams (silicones, higher acyclic monoalcohols), biocides (copper, tin, zinc, lead, mercury), conventional dyes, pigments, fillers, optical brighteners, and wet strength additives.

The preparation of the papermaking sizing according to the invention comprises generally known technological processes. Advantageously, solutions of polymeric carboxylic acids, resin acids and / or derivatives thereof are dispersed together and homogenized in water containing surfactants and / or protective colloids. The process is carried out at a pressure of 100 to 300 kPa and at a temperature of 20 to 95 ° C. If necessary, the necessary additives are added. Stable aqueous 20 to 50 wt. a sizing agent dispersion having a pH of 6-11 and an average particle size below 1 µm. They are used for both surface and internal sizing of all types of paper, cardboard and paperboard.

The invention is further illustrated by the following examples. Softening temperatures of resin acids and their derivatives were determined according to ČSN 65 7060.

In the examples, the ingredients used and the sizing agents prepared therefrom are characterized as follows:

Polymeric carboxylic acid

It was prepared by the Friedl-Craft reaction from pentene-hexene-cyclopentadiene-piperylene-indene-maleic anhydride. It has a number molecular weight Rn of 4000 and contains 125 g of COOH / 1000 g of polymeric acid.

Polymeric carboxylic acid II

It was prepared by the Friedl-Craft reaction from pentene-hexene-butadiene-indene-cyclopentadiene-maleic anhydride. It has a number molecular weight Rn of 500 and contains 50 g COOH / 1000 g polymeric acid.

Polymeric acid III

It was prepared by anionic polymerization of 1,4-butadiene and acrylic acid. It has a number molecular weight Rn of 20,000 and contains 110 g of COOH / 1000 g of polymeric acid.

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Polymeric carboxylic acid IV

It was prepared by the free-radical polymerization of styrene, methyl methacrylate and acrylic acid up to a molecular weight of 15,000 and a content of 80 g of C00H / 1000 g of polymeric acid,

Resin Acid

Partially hydrogenated rosin with a softening point of 85 ° C and a content of 120 g COOH / 1000 g resin.

Resin acid B

It was obtained by fractional distillation of crude talo oil having a softening temperature of 55 ° C and a content of 40 g COOH / 1000 g resin.

Resin acid C

Reaction product 87 wt. parts by weight of resin acid A, 10 wt. parts by weight of maleic anhydride and 3 wt. parts of paraformaldehyde having a softening temperature of 95 ° C and a content of 160 g COOH / 1000 g resin.

Resin acid D

Reaction product 85 wt. parts of resin acid A and 15 wt. parts of maleic anhydride having a softening point of 110 ° C and a content of 180 g of COOH / 1000 g of resin.

Example 1

The prepared paper sizing consists of 95 wt. parts by weight of polymeric carboxylic acid I and 5 wt. In the preparation, a mixture of 950 wt. parts of polymeric carboxylic acid I and 50 wt. parts of resin acid A are dissolved in dispersants at 25 [deg.] C. in 60 parts by weight, parts of the solvent system methylene chloride-isopropanol 1: 1, 66 parts by weight are added. parts by weight of the tetrasodium salt of N- (1,2-dicarboxyethyl) -N-octadecylsulfosuccinate and then successively 550 wt. parts of a protective colloid solution containing 75 wt. parts of casein and 5 wt. parts of ammonia water 24%. In dispersants, the temperature is raised to 35 ° C and stirred for 5 minutes at 150 rpm. min ^-1 , then vigorously disperse at 6000 rpm while adding 650 wt. parts of demineralized water preheated to 85 ° C. The prepared dispersion is pumped through a high-pressure homogenizer, where it is homogenized at 40 MPa to a boiler, in which the solvents are removed by distillation at 90 DEG C. and 6 kPa, and further through a condenser ¹ , where it is cooled to 20 ° C. The sizing agent obtained has a dry matter content of 45%, an average dispersion particle size of 0.5 to 0.6 µm, and a Hercules Sizing Tester sizing at an absolutely dry sizing rate of 1% when the ash in the paper is 11.2%. 420 s.

Example 2

In the preparation of the paper size, a mixture of 50 wt. parts by weight of polymeric carboxylic acid II, 150 wt. parts of resin acid a and 800 wt. parts of resin acid C dissolved in dispersants at 25 ° C in 800 wt. parts by weight of methylene chloride, 91 wt. parts by weight of the sodium salt of sulfated pentaethoxylated nonylphenol and then successively 200 wt. parts of gelatin solution 50%. Stir for 5 minutes at 150 rpm. min < -1 >, then vigorously dispersed at 6000 rpm while adding 1,826 wt. The dispersion obtained is pumped through a high-pressure homogenizer set at a pressure of 50 MPa into a boiler, in which methylene chloride is removed by distillation at 30 ° C and 40 kPa. The obtained sizing agent has a dry matter content of 35%, an average dispersion particle size of 0.7 µm, and an absolutely dry sizing charge of absolutely dry fiber of 0.8% (ash in paper is 11.2%) exhibits a Hercules Sizing Tester sizing ratio of 550 sec.

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Example 3

In the preparation of the paper size, a mixture of 100 wt. parts of polymeric carboxylic acid III, 809 wt. parts by weight of resin acid B, 81 wt. parts by weight of acrylic acid and 10 wt. parts of 24% ammonia water dissolved in 400.wt. 150 parts by weight of 1,2-dichloropropane in a dispersant at 20 DEG C. are added. parts by weight of the ammonium salt of sulfated alkylphenocypols / (ethyleneoxy) ethanol and then successively 100 wt. parts of a 3% carboxymethylcellulose solution. In the dispersant, the temperature is raised to 95 ° C with the addition of 800 wt. parts of demineralized water preheated to 90 ° C and mixed first at 150 rpm for 5 minutes. min ^-1 , later it dispersed intensively at 6000 rpm. min ^-1 , at a temperature of 95 ° C and a pressure of 250 kPa. The prepared dispersion is pumped through a high-pressure homogenizer, which is homogenized at 40 MPa to a boiler, in which 1,2-dichloropropane is removed by distillation at 90 ° C and 6 kPa. The dispersion obtained is passed through a high-performance condenser and rapidly cooled to 20 ° C. The sizing agent has a dry matter content of 48%, an average dispersion particle size of 0.4-0.8 µm, and an absolutely dry sizing charge of absolutely dry fiber of 1% (ash in paper is 11.2%) exhibits a Hercules Sizing Tester sizing ratio of 380 sec.

Example 4

In the preparation of the paper size, the mixture is proceeded such that a mixture of 200 wt. parts of polymeric carboxylic acid IV and 800 wt. parts of resin acid D are dissolved in a dispersant at 60 ° C in 300 wt. parts by weight of the solvent system methylene chloride-ethanol 2: 1, 125 wt. parts by weight of the ethoxylated fatty alcohol disodium salt of semisulfosuccinate and then successively 600 wt. parts of a colloid solution containing 50 wt. parts of casein, 5 wt. parts of ammonia water and 25 wt. parts of carnauba wax. In the dispersant, the temperature is adjusted to 50 ° C, 800 wt. parts of demineralized water and mix first for 5 minutes at 150 rpm. min ^-1 then disperse intensively at 6000 rpm. min ^-1 at 50 ° C and 150 kPa. The prepared dispersion is pumped through a high-pressure homogenizer, where it is homogenized at a pressure of 50 MPa into a boiler to remove solvents. The distillation is carried out at a temperature of 50 ° C and a pressure of 20 kPa. The dispersion cooled to 20 ° C has a dry matter content of 40%, an average dispersion particle size of 0.5 µm and a Hercules Sizing sizing ratio of 0.8% (an ash in paper is 11.2%) at an absolutely dry sizing dose of 0.8%. Tester 460 s.

Claims (1)

Process for the production of paper sizing based on aqueous dispersions of natural and synthetic resins and additives of 20 to 40 wt. parts of a blend of polymeric carboxylic acids having an average molecular weight of ffin of 500 to 20,000 and a content of 45 to 125 g of COOH / / 1000 g with resin acids and / or derivatives thereof, in particular with adducts, β-unsaturated carboxylic acids having 3 to 6 carbon atoms or their anhydrides with a softening point of 50 to 120 ° C and a content of 40 to 180 g COOH / 1000 g, in a weight ratio of 0.95: 0.05 to 0.05: 0.95, characterized in that the mixture of said resins is dissolved in 2 to 30 wt. parts of organic solvents from the group of methylene chloride, 1,2-dichloropropane, ethanol, propanol and isopropanol at a temperature of 15 to 80 ° C and the solution is dispersed at temperatures of 20 to 95 ° C and pressures of 100 to 300 kPa with 60 to 20 wt. containing 1 to 10 wt. parts of surfactants and / or protective colloids, after which the organic solvent is removed by distillation at a temperature of 30 to 90 ° C and a pressure of 6 to 50 kPa and the resulting dispersion is cooled below 25 ° C, optionally topped up with water to form a dispersion of dry matter content. % to 50 wt.