FI64661C - FOERFARANDE FOER FRAMSTAELLNING AV HYDROFILA POLYOLEFINFIBRER ANVAENDNING AV NAEMNDA FIBRER I EN PAPERPRODUKT SAMT EN POYMERBLANDNING FOER ANVAENDNING I NAEMNDA FOERFARANDE - Google Patents

Abstract

Hydrophilic polyolefin fibres are mfd. by mixing a fibrous polyolefin compsn. obtd. by projection by discharge, and contg. a carboxylic function, with an aq. dil. mixt. of water sol. anionic and cationic polymers contg. N. - The cationic polymer is the reaction prod. of epichlorohydrin and (a) an amino-polyamide derived from a dicarboxylic acid and a polyalkylene-polyamide contg. two primary amino gps. and >=1 sec. or tert. amino gp. or (b) a polyalkylene-polyamine of formula H2N(CnH2nNH)xH (I) (where n is a whole no. 2-8; x is a whole no. >=2, or (c) a poly(dialkylamine) or (d) a poly-amino-urylene derived from urea and a polyamine contg. >=3 amino gps. >=1 of which is tert. - The anionic polymer is the reaction prod. of glyoxal and (a) a polyacrylamide contg. 2-15% acrylic acid units, or (b) a branched, partially hydrolysed poly(beta-alanine) contg. 1-10 mol. % carboxyl gps. w.r.t. recurring amide units. The wt. ratio between the cationic polymer and the anionic polymer is 1:3-7. - The fibres are readily dispersible in water and can be admixed with wood pulp fibres to form a pulp which can be conferted into high quality paper with increased tensile strength as compared with a paper prepared without the polymer component.

Description

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Patent · och registerstyrelsen '' Ansökan utiajd och utUknften publicsrad 31.08.83 (32) (33) (31) Claim claimed - Begird prlorltet 07.09.76 USA (US) 721133 (71) Hercules Incorporated, 910 Market Street, Wilmington, Delaware 19899 »USA (US) (72) Terence William Rave, Wilmington, Delaware, USA (US) (71) Oy Heinänen At (5 ^) Method for the preparation of hydrophilic polyolefin fibers, the use of said fibers in a paper product, and the polymer used for the said team n> i link - Förfarande för framstäl) Ning av liydrofila poiyolefinfi i> r «r, envändrii.ng av näimuia fjb.rrr i en j>: φ | κ * rup roduk t ,, asuni on p.-lymorUlau.lning Pör tu 1 vän The present invention relates to a process for the preparation of hydrophilic polyolefin fibers, in which the polyolefin fibers are treated with an aqueous mixture of cationic and anionic polymers. The fibers produced by the process are readily dispersible in water and can be blended with wood pulp fibers to produce a pulp that can be made into high quality paper using standard papermaking techniques. The invention furthermore relates to a certain mixture of cationic and anionic polymers to be used in the process and to the use of the fibers prepared according to the process in a paper product.

In recent years, considerable work has been done to develop polyolefin fiber-containing pulps with hydrophilic properties. One method developed for this purpose to provide hydrophilic properties is described in U.S. Patent 3,743,570. According to this publication, high specific surface area polyolefin fibers are treated with a hydrophilic colloidal polymeric additive containing a cationic polymer such as gelamine. formaldehyde, and an anionic polymer such as carboxymethylcellulose. Another method developed for making hydrophilic polyolefin pulps is one in which a mixture of polyolefin and an additive such as a hydrophilic polymer, for example polyvinyl alcohol, is extruded. In this extrusion process, the polyolefin and the hydrophilic additive are dispersed in a liquid which is not a solvent of either component at its normal boiling point, after which the resulting mixture is heated at atmospheric pressure to dissolve the polymer and all solvent-soluble additives. so as to form a fibrous product.

A significant disadvantage associated with these pulps containing hydrophilic polyolefin fibers has been that when blended with wood pulp, the resulting paper products have significantly lower strength than papers made from wood pulp alone. However, certain improvements in the strength of paper made from blends of polyolefin pulps and wood pulps have been achieved by giving the polyolefin pulp anionic character. For example, DE-A-2 413 922 proposes the preparation of anionic pulps by extruding mixtures of copolymers of polyolefins and olefinic compounds into maleic anhydride or acrylic or methacrylic acids. Mixtures of these pulps and wood pulp have been used to produce papers with better tensile strengths than paper without a copolymer component.

It is an object of the present invention to provide a paper with blends of polyolefin fiber-containing pulps and wood pulp with very good strength properties. The process for producing polyolefin fibers according to the invention is characterized in that the blown-out fibrous polyolefin mixture having carboxylic functionality is brought into effective contact with a dilute aqueous mixture of a water-soluble nitrogen-containing cationic and anionic polymer in which the cationic anionic polymer is and (a) an aminopolyamide derived from dicarbonate-Posta and a dust alkylene polyamine having two primary amine groups and at least one secondary or tertiary amine group, or (b) a polyalkylene polyamine having the formula H2N ^ CnH2nNH_xH sa n is an integer from 2 to 8 and x is an integer of 2 or more, or (c) a reaction product of poly- (diallylamine) or (d) a polyaminourulene derived from urea and a polyamine having at least three amine groups, at least one of which is tertiary. and which anionic polymer is glyoxal and (a) a polyacrylamide containing about 2-15% acrylic acid groups, or (b) a reaction product of a partially hydrolyzed branched poly- (β-alanine) containing about 1-10 mole% carboxyl groups based on repeating amide units, wherein the weight ratio of cationic polymer to anionic polymer is in the range of about 1: 3-1 7.

v.

According to one embodiment of the present invention, the copolymer of polypropylene and ethylene acrylic acid is dispersed in a solvent such as methylene chloride, and the dispersion is heated in a closed system to about 190 ° C to dissolve the polymer components in the solvent. Under these conditions, the vapor pressure of methylene chloride is of the order of 42 bar. Nitrogen is then added to the mixture to increase its vapor pressure to about 70 bar, after which the resulting mixture is blown to atmospheric pressure through a nozzle, resulting in evaporation of the methylene chloride solvent and formation of a fibrous product. The fibrous product is then suspended in an aqueous medium prepared by mixing, for example, a dilute aqueous solution of poly (diethylenetriamine-adipic acid) modified with epichlorohydrin with a dilute aqueous solution of refining in a plate refiner. The treated fibers are then recovered and stored as a wet cake or, alternatively, the fibrous suspension can be used directly in the papermaking process.

Some embodiments of the present invention have been generally described above. In the following examples, they are described in more detail. All amounts are by weight.

Esimerkki_A

4,646,661

A cationic, water-soluble, nitrogen-containing polymer was prepared from diethylenetriamine, adipic acid, and epichlorohydrin. 0 to 97 moles of diethylenetriamine were added to a reaction vessel equipped with a mechanical stirrer, thermometer and condenser. Then, one mole of adipic acid was gradually added to the reaction vessel by stirring the reaction mixture. After the acid was dissolved in the amine, the reaction mixture was heated to 170-175 ° C and maintained at this temperature for one or 1-5 hours, during which time the reaction mixture became very fluid. The reaction mixture was then cooled to 140 ° C, after which enough water was added that the resulting polyamide solution had a solids content of about 50%. A sample of polyamide was isolated from this solution, which was found to have a reduced intrinsic viscosity of 0.155 deciliters per gram as measured from 2% ammonium chloride in 1 M aqueous solution. The polyamide solution was diluted to 13.5% solids and heated to 40 ° C, and epichlorohydrin was slowly added in an amount corresponding to 1.32 moles per mole of secondary amine in the polyamide. The reaction mixture was then heated to 70-75 ° C and maintained at that temperature until its Gardner viscosity had reached E-F. Water was then added to a solids content of about 13.5% and the solution was cooled to 25 ° C. The pH of the solution was then adjusted to 4.7 with concentrated sulfuric acid. The final product contained 12.5% solids and had a Gardner viscosity of B-C.

E si ^ merk k i _B

Another typical cationic, water-soluble, nitrogen-containing polymer was prepared using epichlorohydrin and a commercially available fluid mixture of polyamines as reaction components. This mixture contained at least 75% bis- (hexamethylene) triamine and higher homologues, with the remainder containing lower molecular weight amines, nitriles and lactans. The reaction was carried out in a boiler equipped with a blast-based vacuum system used to remove vapors through a condenser instead of allowing these vapors to escape through an open opening in the boiler.

ti 5 64661

704 parts of water and 476 parts of epichlorohydrin were placed in the kettle, after which 420 parts of the commercially available mixture of polyamines were added to the kettle over 35 minutes while cooling the reaction mixture so that its temperature did not exceed 70 ° C. After the addition of the amine, 6 parts of 20% aqueous sodium hydroxide solution was added to increase the reaction rate over a total of 160 minutes at about 70 ° C, after which the reaction mixture was diluted with 640 parts of water to reduce the viscosity to about Gardner C. About 44 parts of 20% aqueous sodium hydroxide solution was added over 105 minutes. The Gardner viscosity value S was reached in 215 minutes, at which time the reaction was stopped by adding 26 parts of concentrated sulfuric acid dissolved in 1345 parts of water to the reaction mixture. The resulting solution had a Gardner viscosity of D, after which sulfuric acid and water were added so that the pH of the solution was 4 and the solids content of the solution was 22.5%.

Esimerkki_C

A cationic, water-soluble, nitrogen-containing polymer was prepared whose main reaction components were methyldiallylamine and epichlorohydrin. To 333 parts of methyldiallylamine was slowly added 290-295 concentrated hydrochloric acid, the pH of the solution being 3-4. Nitrogen was then passed through the solution and the temperature was raised to 50-60 ° C. Simultaneously, 10.7% aqueous sodium bisulfite solution and 10.1% aqueous t-butyl hydroperoxide solution were added simultaneously to the reaction mixture over 4 to 5 hours until the reduced specific viscosity of the resulting polymer, poly (methyldiallylaminediamine hydrochloride), was 0.2 measured % as a solution of an aqueous solution of 1 molar sodium chloride at 25 ° C. The amounts of both sodium bisulfite and t-butyl hydroperoxide were 2 mol% based on the repeating polymer groups.

To the above polymer solution was then added 600 parts of a 4% aqueous sodium hydroxide solution, and the temperature of the resulting solution was adjusted to 35 ° C. After an amount of water having a solids content of 22% was added to the polymer solution, 416.3 parts of epichlorohydrin were added thereto. The temperature of the reaction mixture was maintained at 45 ° C, increasing the Gardner viscosity of the mixture from below A to B +. After adding about 304 parts of 36% hydrochloric acid to the reaction mixture, it was heated to 80 ° C and 64661 was maintained at this temperature by the continuous addition of hydrochloric acid until the pH of the reaction mixture had stabilized at 2 within one hour.

The reaction mixture was then cooled to 40 ° C, adjusted to pH 3.5-4 by the addition of 4% sodium hydroxide, and then diluted to 20% solids.

The plastic product obtained by the above-mentioned method was activated by basifying it before using it according to the present invention. This was done by adding 18 parts of water and 12 parts of 1 molar sodium hydroxide solution per 10 parts of a solution containing 20% solids of plastic. The resulting solution containing 5% solids was allowed to stand for 15 minutes, after which its pH was above 10. Had this pH not been reached, sodium hydroxide could have been added.

E s i ^ merkk

A different, usable, cationic, water-soluble, nitrogen-containing polymer was prepared from bis- (3-aminopropyl) -methylamine, urea, and epichlorohydrin. 210 parts of amide and 87 parts of urea were placed in a reaction vessel, heated to 175 ° C, kept at this temperature for one hour, after which the mixture was cooled to 155 ° C. 375 parts of water were added to the reaction product, after which the resulting solution was cooled to room temperature.

To 217 parts of the above solution were added 321 parts of water, 29 parts of concentrated hydrochloric acid and 89.6 parts of epichlorohydrin. The temperature of the reaction mixture was maintained in the range of 39-42 ° C for about 85 minutes, during which time the Gardner viscosity of the mixture increased from A-B to L +. Then, 60 parts of concentrated hydrochloric acid was added to the mixture, and the resulting mixture was heated at 60-75 ° C for 4 hours, after which more than 9 parts of hydrochloric acid were added over about 1-1.5 hours to bring the pH of the mixture below 2. The mixture was cooled. then to room temperature. The resulting epichlorohydrin-modified polyaminourulene product contained 27% solids.

li 7 64661

Prior to using the product described above in accordance with this invention, it also had to be activated by basification. Activation was accomplished by adding 10 parts of the above product to 10 parts of 1 M sodium hydroxide solution, standing the resulting product for 15 minutes, and then diluting the solution (13.5% solids) to 5% solids or less for its intended use.

Pre character ^ ^ E

An anionic, water-soluble nitrogen-containing polymer was prepared from acrylamide, acrylic acid and glyoxal. To the reaction mixture equipped with a mechanical stirrer. with a thermometer, a condenser, and a nitrogen gas nozzle, 890 parts of water were placed. 98 parts of acrylamide, 2 parts of acrylic acid and 1-1.5 parts of a 10% aqueous solution of copper sulfate were then dissolved in water. Nitrogen was bubbled through the resulting solution and heated to 76 ° C, at which point 2 parts of ammonium persulfate dissolved in 6.5 parts of water were added. The temperature of the reaction mixture then rose to 21.5 ° C over 3 minutes after the addition of persulfate. After the temperature was lowered to 76 ° C, the reaction mixture was kept at this temperature for 2 hours, after which the reaction mixture was cooled to room temperature. The resulting solution had a Brookfield viscosity of 54 centipoise at 21 ° C and less than 0.2% acrylamide based on the total amount of polymer.

To 766.9 parts of the above solution (76.7 parts of a polymer having 75.2 parts or 1.06 moles of repeating amide groups) was added 39.1 parts of a 40% aqueous solution of glyoxal (15.64 parts or 0.255 equivalents calculated from the repeating amide groups of glyoxal) . The pH of the resulting solution was adjusted to 9.25 by adding 111.3 parts of a 2% aqueous solution of sodium hydroxide. In about 20 minutes after the addition of sodium hydroxide, the Gardner viscosity of the solution had increased from A to E. The reaction was then stopped by adding 2777 parts of water and about 2.6 parts of a 40% aqueous solution of sulfuric acid to the reaction mixture. The resulting solution had a pH of 4.4 and contained 2.2% solids.

8

Example F

6 4 6 61

Another type of typical water-soluble nitrogen-containing polymer was prepared using only acrylamide and Gly-oxal as reaction components. In a reaction vessel equipped with a stirrer, a thermometer and a vertical condenser, 350 parts of acrylamide, 1 part of phenyl-beta-naphthylamine and 3870 parts of chlorobenzene were placed. This mixture was maintained at 80-90 ° C with vigorous stirring to partially melt and partially dissolve the acrylamide. Then, 1 part of sodium hydroxide flakes was added to the reaction mixture, followed by the so-called after the induction step, an exothermic reaction took place, after which the polymer was deposited on the stirrer and on the wall of the reaction vessel. Then, 1 part or more of sodium hydroxide flakes was added to the reaction mixture at 30 minute intervals, after which the reaction mixture was kept at a temperature of about 90 ° C for one hour. The hot chlorobenzene was then removed by decantation and the remaining solid product, branched water-soluble poly (β-alanine), was washed three times with acetone and then dissolved in 1000 parts of water at room temperature. This gave a cloudy solution with a pH of about 10.5, which was maintained at about 75 ° C for about 30 minutes to effect partial hydrolysis of the amide groups in the poly- (β-alanine) and through which a strong stream of steam was passed until the remaining chlorobenzene in the solution was removed and the polymer was completely dissolved. After cooling, the pH of the solution was adjusted to 5.5 using sulfuric acid. The dissolved polymer contained about 2 mole% carboxyl groups, as determined by potentiometric titration.

To a 15% aqueous solution of the above polymer was added a 40% aqueous solution of glyoxal in an amount such that the mixture contained 25 mole% Gly oxalate based on the repeating amide groups in the polymer. The pH of the resulting solution was slowly raised to about 9.0-9.5 at room temperature by the addition of dilute aqueous sodium hydroxide, and the pH of the mixture was maintained at this value until the Gardner viscosity had risen by 5-6 units. The solution was then rapidly diluted with water to 10% solids and the pH was adjusted to 5.0 with sulfuric acid.

li 9

Example 1 64661 90 parts of isotactic popypropylene having an intrinsic viscosity of 2.1 in decahydronaphthalene at 135 ° C and 10 parts of ethylene-acrylic acid copolymer (Dow. 92: 8 ethylene: acrylic acid, melt index 5.3) were placed in a closed autoclave 400 lene chloride as a solvent. The contents of the autoclave were stirred and heated to 220 ° C, at which temperature the vapor pressure of the autoclave was raised to 70 bar by the addition of nitrogen. The resulting solution was blown from the autoclave to atmospheric pressure through a nozzle 1 mm in diameter and 1 mm in length, resulting in the evaporation of methylene chloride used as a solvent and the formation of the desired fibrous product. This fibrous product was then plate refined for 6 minutes in a Sprout Waldron plate refiner in a 0.25% consistency aqueous medium containing 0.1% of a mixture of the cationic polymer of Example A and the anionic polymer of Example E to give the cationic polymer. and the weight ratio of anionic polymer in the plastic mixture was 1: 5. The refined fibrous product was washed with water, after which it contained 8.5% of the plastic adhering thereto as determined by nitrogen analysis.

Example 2

The fibrous product prepared by blowing out according to Example 1 was plate refined in the same manner as in this example except that the aqueous medium contained 0.05% of a mixture of cationic and anionic polymer. The refined fibrous product, washed with water, contained 5.2% of the adhering plastic as determined by nitrogen analysis.

Example 3

The process of Example 1 was repeated using the following conditions to obtain a blown fibrous product: 95 parts polypropylene, 5 parts ethylene-acrylic acid copolymer (Dow 88:12 ethylene: acrylic acid, melt index 7), a mixture of 360 parts methylene chloride and 40 parts of acetone, as solvent, at a temperature of 220 ° C and a pressure of 84 bar. The fibrous product thus obtained, after the plate refining according to Example 1, contained 9.0% of the plastic adhering thereto, determined by nitrogen analysis.

Example 4

The process of Example 1 was repeated except that the following conditions were used to prepare the blown fibrous product: 90 parts of isotactic polypropylene having an intrinsic viscosity of .d., 1.3 in decahydronaphthalene at 135 ° C, 10 parts of ethylene-acrylic acid copolymer (Union Carbide, 9 ^ 6 ethylene: acrylic acid), 900 parts of methylene chloride as solvent at a temperature of 200 ° C and a pressure of 70 bar. The fibrous product prepared by this blow-out method was then refined according to Example 1, whereby the fibers obtained contained 7.2% of the plastic adhering thereto, as determined by <nitrogen analysis.

Example 5

The blown-out fibrous product was made by the method of Example 1, but using 80 parts of polypropylene, 20 parts of the ethylene-acrylic acid copolymer of Example 4, 400 parts of methylene chloride at a temperature of 210 ° C and a pressure of 70 bar. The product was plate refined according to Example 1 to give a fibrous slurry having 6.7% of adhering plastic as determined by nitrogen analysis.

Examples 6 and 7

Example 5 was repeated under otherwise identical conditions except that the cationic polymer of Example A and the anionic polymer of Example E were used in a weight ratio of 1: 7 to the plastic mixture of Example 6 and in a weight ratio of 1: 3 to the mixture of Example 7. The adhesion of the plastic to the fibrous product of Example 6 was 6.5% and to the fibrous product of Example 7 was 5.1%.

Example 8 11 64661

All synthetic pulps of Examples 1-7 were blended with bleach kraft pulp (50:50 RBK: WBK, pH 6.5, 500 Canadian

Standard Freeness) with a ratio of 30% synthetic pulp to 70% wood pulp. Handmade sheets of paper were made from the blends and dried and calendered using a compression force of 90 bar / cm at 60 ° C. The brightness, opacity, tensile strength and Mullen tear strength of the product were then determined and the results obtained are shown in Table 1. The values shown in this table are the tensile strength and Mullen tear strength as a percentage of tensile strength and Mullen tear strength in the reference 100% wood pulp. to a basic weight of 18 kg / rice.

table 1

Eg Brightness Opacity Tensile strength Mullen tear ___________ {%) _____________ (%) ___________ (%) _______ strength___________ 1 87.3 85.8 90 86 2 87.9 87.2 82 84 3 87.6 87.7 78 78 4 84.4 81.5 71 68 5 87.2 82.5 78 72 6 87.4 81.8 76 76 7 87.5 82.8 79 63

From the above values, it will be seen that the present invention provides a paper having a tensile strength of about 70-90% and a Mullen tear strength of about 60-85% of the corresponding values of a paper made from 100% wood pulp.

Esimerkki_9

The process of Example 1 was repeated using 200 parts of crystalline polypropylene containing 3% by weight of maleic anhydride, 2672 parts of methylene chloride at a temperature of 200 ° C and a pressure of 70 bar. The fibrous product prepared by blowing was refined into a plate according to Example 1 to obtain fibers with 2.7% of the plastic adhering thereto. The refined pulp was mixed into the wood pulp and then 64661 sheets made by hand from the mixture were made. which were examined according to Example 8. The sheets obtained had a brightness of 82%, an opacity of 80%, a tensile strength of 67% and a Mullen tear strength of 71.

Esimerkki_10

The process of Example 1 was used to prepare a blown fibrous product from crystalline polypropylene containing 6% by weight of acrylic acid. Water and hexane in a weight ratio of 3: 2 were used as dispersant. The fibrous product 1 was refined according to Example 1 except that a 0.5% aqueous solution of a mixture of the cationic polymer of Example A and the anionic polymer of Example F was used, the weight ratio of cationic polymer to anionic polymer being 1: 3. The amount of plastic adhering to the fibers was 7.2. %. The refined pulp was mixed into the wood pulp and the mixture was made into handmade sheets which were examined according to Example 8. The sheets obtained had a brightness of 87%, an opacity of 79.3% and a tensile strength of 77%.

Example _11 ^

The polypropylene of Example 1 was replaced with 90 parts of high density polyethylene (DuFont, melt index 5.5-6.5 at 190 ° C) and the mixture with ethylene-acrylic acid copolymer was blown out of solution in ethylene chloride at 200 ° C and 70 bar. A fibrous product for sheet refining according to Example 1, and the refined pulp was mixed with wood pulp, after which the mixture was made into handmade sheets, which were examined in the same manner as in Example 8. The sheets obtained had a brightness of 84%, an opacity of 80%, a tensile strength of 68% and a Mullen tear strength of 69%.

12 parts of polypropylene having an intrinsic viscosity of 2.2 deca-hydrone at 135 ° C and 870 parts of diethylene chloride at 222 ° C and 70 bar were used as the fibrous product. by the process of Example 1. 60 parts of the fibrous product were suspended in 6000 parts of water, the resulting suspension was stirred, and air containing 0.02 g / l of ozone was passed through the suspension to room temperature at a flow rate of 0.002 liters per minute for 15 minutes. Under these conditions, ozone 64661 adhered to the fibers at 0.53% by weight of the fibers and the acid number of the fibers corresponded to 0.033 milliequivalents per gram of carboxyl groups of fibers. Wet ozonated fibers were plate refined as in Example 1 and the refined product was found to contain 5.4% of the plastic adhering thereto, calculated by nitrogen analysis. The Raf-finished pulp was then blended into wood pulp (50:50 RBK: WBK, 750 Canadian Standard Freeness), and sheets were made from the blend by hand, which were examined as in Example 8. The sheets obtained had a brightness of 27.3 56, an opacity of 87.6% and a tensile strength of 84%.

Prefix ^ 13

The process of Example 12 was repeated except that the ozonation reaction took place in one hour. The adhesion of ozone to the fibers was 1.9% and the acid number of the fibers corresponded to 0.129 milliequivalents of carboxyl groups per gram of fibers. After sheet refining, the fibers contained 5.1% of the plastic adhering thereto, and the handmade sheets prepared according to Example 8 had a brightness of 87.2%, an opacity of 87.76, and a tensile strength of 89%.

E s i_merkk i_l 4

The process of Example 13 was repeated except that high density polyethylene was used instead of polypropylene and pentane was used as the solvent instead of methylene chloride. The amount of ozone adhered was 1.8%, the acid number was 0.115 milliequivalents per gram, the amount of adhered plastic was 8.8% and the brightness of the hand-made sheets was 85%, the opacity was 87% and the tensile strength was 100 56,

Example 15 Using the general technique set forth in Example 2, a fibrous product of high density polyethylene with 5% maleic anhydride was prepared by blowing to give a product with a 1% suspension per 60 parts of fibers in water, and ozone was passed through the fiber suspension at 25 ° C for one hour. at a flow rate of 0.039 g / min. The ozonated fibers were plate refined in 0.125% consistent aqueous medium containing the plastic mixture of Example 1 0.05 56. The plastic adhesion in the refining process was 5.4% and after mixing with 14,646,661 wood pulp and forming the handmade sheets of Example 8, the resulting sheet brightness 87.5%, opacity 85% and tensile strength 85%.

Example 16

The polypropylene fiber product was prepared using conditions similar to Example 12. A portion of this product was mixed with 5% by weight, based on the weight of the polypropylene fibers, of wood pulp (50:50 RBK: WBK) and the fiber mixture was refined until it became water permeable. The 1% aqueous mixture was then ozonated by passing ozone through a fiber dispersion at room temperature until the acid number of the ozonated fibers corresponded to 0.07 milliequivalents of carboxyl groups per gram of fibers. 30 parts of ozonated pulp were mixed with 70 parts of wood pulp, and to the samples taken from the resulting mixture was added in a papermaking machine 5% of the total weight of fibers (a) a plastic mixture of Example 1, (b) a mixture of a cationic polymer of Example B and an anionic polymer of Example E the mixture ratio was 1: 5 parts by weight, (c) a mixture of the cationic polymer of Example C and the anionic polymer of Example E, wherein the mixture ratio of the cationic substance to the anionic substance was 1: 5 parts by weight, and (d) a mixture of was the cationic polymer of Example D and the anionic polymer of Example E, wherein the mixture ratio of the cationic agent to the anionic agent was 1: 5 by weight. After the additives were thoroughly mixed into the pulp, sheets were made by hand, the properties of which were examined in the same manner as in Example 3. The results are shown in Table 2.

Taulukko_2

Additive _______ Brightness__________ (¾) (%) (%) (a) 87.8 84.5 67 (b) 87.1 84.3 68 (c) 87.6 84.4 74 (d) 87.8 84.2 69 64661

Comparative research results obtained from hitherto known methods and polymeric additives are shown in the following examples. All amounts are parts by weight again.

Comparative Example 17

By the method of Example 1, a fibrous product was prepared from 95 parts of polypropylene and 5 parts of an ethylene-acrylic acid copolymer according to said example, and various samples of the fibrous product were plate-refined in an aqueous medium containing 0-1% (a) of the plastic mixture of Example 1, (b ) a mixture of 1: 1 melamine formaldehyde polymer (Paramel HE, American Cyanamid) and carboxymethylcellulose (CNC, DS 0.4, Hercules), and (c) a mixture of 2: 1 Paramel and CMC polymers. Each of the prepared pulps was mixed into the wood pulp and made into sheets by hand, which were examined in the same manner as in Example 8. The results obtained are shown in Table 3.

T e u K o 3

Additive__Brightness__2.E®®i £ ®® £ iii .____ Mullen strength (%) (%> (¾) (%) (a) 82.5 87.0 73.5 56.0 (b) 81.8 86 , 7 38.2 24.9 (c) 84.3 88.2 44.1 26.0 These figures show that replacing the plastic mixture (a) with known mixtures (b) and (c) in the process of the present invention does not provide paper, which would have the desired strength.

Z® £ i®.iiH®®i! ®, £ iilsi_i®

The blown fibrous product, substantially identical to Example 1, was plate refined for 6 minutes in water on a Sprout Waldron plate refiner at 0.25% consistency. The refined product was mixed with bleached kraft paper pulp (50:50, RBK: WBK, 500 Canadian Standard Freeness) according to Example 8, after which 5%, based on the total fiber weight of the fibers, of the plastic of Example 7 was added to samples of the resulting mixture. , (b) a mixture of the cationic polymer of Example B and the anionic polymer of Example E, wherein the weight ratio of cationic polymer to anionic polymer was 1: 3, (c) a mixture of the cationic polymer of Example C and the anionic polymer of Example E a polymer having a weight ratio of cationic polymer to anionic polymer of 1: 3, and (d) a mixture of Example 17 with Paramel and CMC in a ratio of 2: 1. Other samples taken from the pulp blend were similarly treated with 1.5% blends (a), (b), (c) and (d) based on the total weight of the fibers.

Sheets were hand-made from the mixture and examined according to Example 8. The results are shown in Table 4.

Additive ___ Brightness ___ Opacity ______ ^ ul tear strength (%) (%) (%) (%) 5.0% (a) 82.5 82.4 87 102 5.0% (b) 81.0 83.8 75 103 5.0% (c) 81.3 80.3 92 86 5.0% (d) 85.6 82.0 50 52 1.5% (a) 85.1 83.6 67 69 1.5 % (b) 84.6 82.9 70 68 1.5% (c) 84.0 81.6 70 95 1.5% (d) 86.5 83.1 55 40

From the above figures, it is clear that the additives (a), (b) and (c) of the present invention provide better paper strengths than using the known additive (d).

The blow-off fibrous product was made according to Example 1 except that the ethylene-acrylic acid copolymer was omitted and 100 parts of polypropylene were used. Samples of the fibrous product were triturated in a Varing mixer in an aqueous medium containing 1.0% (a) the plastic of Example 1, (b) a 1: 1 mixture of Paramel and CMC according to Example 17, and (c) a mixture of Paramel CMC products in a 2: 1 ratio according to Example 17. The obtained pulps 17 64661 were mixed into the wood pulp and the mixture was made into sheets by hand, the properties of which were examined according to Example 8. Table 5 shows the results obtained.

T a u l ^ u k 1 <o_5

Additive ___ Brightness ___ Op®®ϋ ££ Ϊϊΐ__Tensile new ___ Mullen tear strength (%) (%) (%) (%) (a) 87.6 87.5 47.7 37.1 (b) 89.6 87.8 36.2 22.9 (c) 89.2 88.2 36.9 26.3

The above values again show the superiority of the additive (a) according to the present invention compared to the known additives (b) and (c). In addition, the values obtained by comparing Example 17 using additive (a) show the important importance of the carboxyl functionality of the anionic polyolefin composition in the application of the process of this invention.

80 parts of polypropylene according to Example 1 and 20 parts of styrene maleic anhydride copolymer (Arco, 75:25, styrene: maleic anhydride, molecular weight 19000) were placed in a sealed autoclave to which 250 parts of water were added and 250 parts of hexane were added. The contents of the autoclave were stirred and heated to 220 ° C, at which temperature the vapor pressure of the autoclave was raised to 70 bar using nitrogen. The resulting emulsion was blown out of the autoclave into the open air through a nozzle having a diameter of 1 mm and a length of 1 mm to give a fibrous substance.

Samples of the fibrous product were plate refined for 6 minutes in a Sprout Waldron plate refiner at 0.25% consistency (a) in water (b) in an aqueous 0.5% solution of the cationic polymer of Example A, (c) in an aqueous 0.5% solution, with glyoxal-modified poly- (acrylamide-co-diallyldimethylammonium chloride) (Parez 631 BC, American Cyanamide), in an aqueous 0.5% solution of melamine-form-aldehyde polymer (Paramel HE, American Cyanamid), (e) in an aqueous 0.5% solution of cationic starch, and (f) an aqueous 0.566 solution in a 0.5% solution of a 1: 3 mixture of a cationic polymer according to Example A and an anionic polymer according to Example F. All the obtained pulps were mixed into the wood pulp, and the mixture was hand-made into sheets, the properties of which were studied as described in Example 8. The numerical values obtained are shown in Table 6.

T 1.] J le 1 <o_0

Refiner Brightness Opacity Tensile strength Mullen tear ___ _ ___ _ _____________ strength_________ (%) (%) (%) (*> (a) 84.2 81.3 41 30 (b) 85.2 79.8 51 48 (c) 85.5 81.4 39 32 (d) 81.6 82.5 48 38 (e) 84.8 79.2 54 48 (f) 82.1 79.4 72 71 These figures show that the various additives used in this in the process according to the invention are not nearly as effective in producing paper of sufficient strength as a specific mixture of cationic and anionic polymers according to the invention, such as mixture (f).

The method of the present invention is very simple and useful because it can produce synthetic pulps which, by mixing with wood pulp, can be used to produce paper products having very good brightness, opacity and softness and good suitability for printing purposes, and low basis weight compared to conventional fillers. paperless. It is also highly advantageous that the synthetic pulps of this invention do not require the presence of separate water-soluble additives, such as starch, in the papermaking process. Additives become unnecessary due to the presence of a cationic polymer component incorporated into the modified fibers prepared by the process of this invention.

The anionic polyolefin blend used in the process of this invention having carboxylic functionality may be a polyolefin having carboxyl groups incorporated into the polymer molecule by treating the polyolefin with a monomer having a carboxylic functionality or oxidizing the polyolefin with a fatty acid. the mixture may be a polyolefin mixed with an anionic polymer having carboxyl functionality. In all cases, the polyolefin may be polyethylene, polypropylene, an ethylene-propylene copolymer, or a mixture of these polyolefins.

If the anionic polyolefin mixture is a mixture of a polyolefin and an anionic polymer having carboxylic functionality, the latter component may be a polyolefin having carboxyl groups directly attached to the polymer chain, a polyolefin having an acrylic acid or their acid, methacrylic acid, methacrylic. formed from ethylene, propylene, styrene, οί, -methylstyrene or mixtures thereof with acrylic acid, methacrylic acid, maleic anhydride or mixtures thereof, in addition to mixtures of all these anionic polymeric components. In certain cases, the polyolefin may also be polyethylene, polypropylene, ethylene-propylene copolymer, or a mixture thereof.

The above blends of polyolefin and anionic polymers having carboxylic functionality preferably have a ratio of the above to the latter of about 95: 5 to about 80-20% by weight, and the amount of carboxyl of the available anionic polymer is preferably about 3 to 30% by weight. In general, the anionic polyolefin blend used in the process of this invention preferably contains a sufficient amount of carboxylic functionality to provide at least 0.01 and most preferably at least about 0.05 ml of carboxyl groups per gram of polyolefin mass. In addition, the amount of carboxyl functionality may be such as to provide one milliequivalent of carboxyl groups per gram of polyolefin mass. The most preferred range of Er-it-t-sin is from about 0.04 to about 0.2 milliequivalents per gram.

In the fiber formation step a, · ...

The dispersant used in the process of the present invention contains an organic solvent which is not a polyolefin blend used to form fibers at a normal boiling point. It may be the methylene chloride shown in most examples, or another halogenated hydrocarbon such as chloroform, carbon tetrachloride, methyl chloride, ethyl chloride, trichlorofluoromethane or 1,1,2-trichloro-1,2,2-trifluoroethane. Also useful are aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane and their isomers, and alicyclic hydrocarbons such as cyclohexane. Mixtures of these solvents may also be used, and water may be present if it is desired to form an emulsion of the polyolefin-containing mixture. In addition, the pressure exerted by the solvent vapors can and is usually increased by using a pressurized inert gas such as nitrogen or carbon dioxide.

In carrying out the fiber production process, the content of the polyolefin mixture in the solution and solvent is usually about 5 to 40% by weight, and most preferably about 10 to 20% by weight. The temperature at which the dispersion of the polyolefin mixture in the solvent is heated to obtain a solution of the mixture depends mainly on the solvent used and must be high enough to cause the mixture to dissolve. Fiber-. % formation temperature is generally in the range of about 100 ° C to 225 ° C. The pressure of the solution containing the polyolefin mixture may be about 40 to 100 bar, but most preferably it is about 60 to 85 bar. The nozzle through which the solution is allowed to discharge is preferably about 0.5 to 15 m in diameter, most preferably about 1 to 5 mm, and the ratio of the length of the nozzle to its diameter is preferably about 0.2 to 10.

In the fiber modification step of the process of this invention, fibers of a fibrous anionic polyolefin blend having carboxyl functionality are effectively contacted with a blend in dilute aqueous solution or dispersion of certain cationic and anionic nitrogen-containing polymers. The weight ratio of cationic to anionic polymer in the mixture is preferably in the range of about 1: 3 to 1: 7. Kationiner. the polymer component in the above mixture can be generally classified as a reaction product of epichlorohydrin and a polymer containing secondary or tertiary amine groups or both. As a typical polymer belonging to this class, there can be mentioned the cationic polymer component used in many examples, namely the reaction product of epichlorohydrin and aminopolyamine derived from di-glycylenetriamine and adipic acid. The preparation of this product is shown in Example A. In general, however, these cationic polymers are reaction products obtained from epichlorohydrin and aminopolyamide, which in turn is obtained from a dicarboxylic acid and a polyalkylene polyamine having two primary amine groups, and at least one secondary or tertiary amine group, as described in U.S. Patent Nos. 2,926,116 and 2,926,154.

Another typical group of polymers belonging to this generally described group of cationic polymers is that in which the polymers are water-soluble reaction products of epichlorohydrin and polyalkylene polyamine. The preparation of such a typical product is described in Example B.

These polyalkylene polyamines which can be reacted with epichlorohydrin have the formula H.N (C H. NH) H, where n is an integer from 2 to 8 and x is an integer from 2 or more, preferably from 2 to 6. Examples of such polyamines are polyethylene polyamines, polypropylene polyamines and polybutylene polyamines. Typical examples of these polyalkylene polyamines are diethylenetetramine, triethylenetetramine, tetraethylenepentamine, bis- (hexamethylene) triamine and dipropylene triamine. Other polyalkyl-1-polyamines suitable for use include methylbis- (3-aminopropyl) amine, methyl-bis (2-aminoethyl) amine, and 4,7-dimethyltriethylenetetramine. Mixtures of polyalkylene polyamines can also be used if desired.

The relative amounts of polyalkylene polyamine and epichlorohydrin used can vary depending on the particular polyalkylene polyamine used. In general, it is preferred that the molar ratio of epichlorohydrin to polyalkylene polyamine be greater than 1: 1 and less than 4.5: 1. In the preparation of a water-soluble plastic from epichlorohydrin and tetraethylenepentamine, good results are obtained when molar ratios of about 1.4: 1 to 1.94: 1 are used. The reaction temperature is preferably in the range of about 40-60 ° C.

One group of cationic polymers suitable for the process of this invention are those in which the polymers are derivatives of epichlorohydrin and poly (diallylamine). The preparation of such products is described in Example C. Other products and methods for their preparation are disclosed in U.S. Patent 3,700,623.

22 64661

The last group of cationic polymers used in accordance with this invention is that in which the polymers are reaction products of epichlorohydrin and polyaminourulene. The preparation of such products is described in Example D. Similar products and their preparation are described in U.S. Patent 3,240,664.

The anionic polymer component of the aqueous solution or dispersion in which the fibers of the anionic polyolefin mixture containing carboxyl functionality is modified is described in the Examples. One such is the reaction product of glyoxal and polyacrylamide obtained by copolymerizing acrylamide with acrylic acid. The preparation of a typical such product is shown in Example E. The amount of acrylic acid gaps in the copolymer can be about 2-15%. Similar products can be prepared by partial hydrolysis of polyacrylamide or poly (acrylamide---alkyl_acrylate), such as a copolymer of acrylamide and ethyl acrylate. All of these polyacrylamides can be prepared by conventional methods to polymerize water-soluble monomers, and most preferably have molecular weights of less than about 25,000, for example in the range of about 10,000 to 20,000.

3 »

Another anionic nitrogen-containing polymer shown in the examples is a reaction product obtained from glyoxal and a polymer prepared by hydrolyzing partially branched, water-soluble poly- (β-alanine). The preparation of such a typical product is shown in Example F. Poly (β-alanine) is prepared by anionic polymerization of acrylamide in the presence of a basic catalyst such as sodium hydroxide, and also in the presence of a vinyl or radical polymerization inhibitor such as phenyl-β-naphthylamine. -almost 500-10,000 and most preferably about 2000 -6,000. Due to the very strong exothermic nature of the anionic polymer reaction, it is advantageous to carry out the reaction in a suitable organic reaction medium such as toluene or chlorobenzene which is inert to the reaction S 3 i and which either dissolves or emulsifies the acrylamide.

O xo => w gdell® is a branched poly- (B-alanine) neutral polymer prepared as described and does not need to be anionically modified for the purposes of the invention. carried out by carrying out a partial modi * hydrolysis of the polymer so that some of the primary amide groups therein are converted to anionic carboxyl groups, for example hydrolysis of poly (β-alanine) can be carried out by heating a slightly basic aqueous polymer solution having a pH in the range of 9-10 , at temperatures of 50 to 100 [deg.] C. The amount of anionic groups attached to the molecular chain must then be about 1 to 10 mol% and most preferably 2 to 5 mol%, based on the repeating amide groups. is modified glyoxal 11a to provide the desired anionic, water-soluble nitrogen-containing polymers used in the present invention. discriminatory basis. The reaction with glyoxal is carried out in a dilute, neutral or slightly alkaline aqueous solution of the polymer at temperatures of about 10 to 50 ° C, preferably 20 to 30 ° C. The amount of glyoxal used in the reaction mixture may be about 10 to 100 mol% and preferably about 20 to 30 mol% based on the repeating amide groups in the polymer. The stability of the obtained solutions is good.

The process according to the present invention makes it possible to produce better paper products from mixtures of wood pulp and polyolefin-containing pulps. The process depends on the nature of the mixture of cationic and anionic nitrogen-containing polymers used in the fiber modification step in each case, and the modification preferably involves the use of a refining process such as a sheet refining process. In addition, various critical factors are involved in the process. These include, for example, that at least 80% of the polyolefin must be present in the anionic polymer blend containing the polyolefin and carboxyl, when this blend forms an anionic polyolefin blend with carboxyl functionality used to form the fibers, that the intrinsic viscosity of the polyolefin must be at least 1.0 that the anionic polyolefin composition having carboxylic functionality must have sufficient carboxyl groups and that the aqueous solution or dispersion in which the anionic fibers are modified must have sufficient plastic. However, treatment within the limits set by these conditions makes it possible to produce a synthetic pulp which, when mixed with wood pulp, allows the production of a paper product with a tensile strength of at least 70% compared to 100% pulp, and the invention provides better brightness, opacity and softness.

Claims (12)

A process for producing hydrophilic polyolefin fibers, which process comprises treating the polyolefin fibers with an aqueous mixture of cationic and anionic polymers, characterized in that a blown-out fibrous polyolefin mixture having carboxyl functionality is subjected to effective contact the cationic polymer is an epichlorohydrin and (a) an aminopolyamide derived from a dicarboxylic acid and a polyalkylene polyamine having two primary amine groups and at least one secondary or tertiary amine group, or (b) a polyalkylene polyamine of the formula H_N (C H) NH n is. an integer of 2 to 8 and x is an integer of 2 or more, or (c) a reaction product of poly- (diallylamine) or (d) polyaminourl-derived derived from urea and polyamine having at least three amine groups, at least one of which is tertiary and which anionic polymer is glyoxal and (a) a polyacrylamide containing about 2-15% acrylic acid groups, or (b) a partially hydrolyzed branched poly- (β-alanine) containing about 1-10 mole% carboxyl groups based on repeating amide units, a reaction product wherein the weight ratio of cationic polymer to anionic polymer is in the range of about 1: 3 to 1: 7. Process according to Claim 1, characterized in that the blown-out fibrous polyolefin mixture with carboxyl functionality is based on polyethylene. Process according to Claim 1, characterized in that the blown-out fibrous polyolefin mixture with carboxyl functionality is based on polypropylene. Process according to Claim 3, characterized in that the blown-out fibrous polyolefin mixture with carboxylic functionality is obtained by using a mixture of polypropylene and an anionic polymer having carboxylic functionality. Process according to Claim 4, characterized in that the anionic polymer having carboxylic functionality is a copolymer of ethylene and acrylic acid. il. 64661 Process according to Claim 3, characterized in that the blown-out fibrous polyolefin mixture having carboxylic functionality is obtained by blowing out polypropylene and oxidizing the fibers obtained to form carboxyl groups in the polypropylene molecule. Process according to Claim 1, characterized in that the cationic, water-soluble nitrogen-containing polymer is a reaction product of epichlorohydrin and an aminopolyamide derived from a dicarboxylic acid and a polyalkylene polyamine having two primary amine groups and at least one secondary or tertiary amine group. Process according to Claim 7, characterized in that the aminopolyamide is derived from adipic acid and diethylenetriamine. Process according to Claim 8, characterized in that the anionic, water-soluble, nitrogen-containing polymer is a reaction product obtained from glyoxal and polyacrylamide obtained by copolymerizing acrylamide with acrylic acid. Process according to Claim 8, characterized in that the water-soluble nitrogen-containing polymer is a reaction product obtained from glyoxal and a polymer obtained by partial hydrolysis of branched, water-soluble poly (β-alanine). Use of hydrophilic polyolefin fibers prepared by the method of claim 1 in a paper product. A mixture of cationic and anionic water-soluble nitrogen-containing polymers for use in the process of claim 1, characterized in that the cationic polymer is a reaction product of epichlorohydrin and an aminopolyamide derived from adipic acid and diethylenetriamine with acrylamide acrylamide and anionic polymer is glyoxal reaction product of polyacrylamide. 26 PATENTKRAV 6 4 661