JPS6335753B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a process for producing hydrophilic polyolefin fibers that are easily dispersible in water and can be blended with wood pulp fibers to provide a pulp that produces high quality paper using conventional papermaking techniques. More particularly, the present invention relates to the production of polyolefin-based fibers and the treatment of these fibers by precipitating submicron-sized hydrated material onto their surfaces. The presence of hydrated material on the surface of the fiber makes the fiber homogeneously hydrophilic and ionic. In recent years, much effort has been devoted to the development of fibrous polyolefin pulps that are hydrophilic and dispersible in water. One method developed to obtain these properties is described in US Pat. No. 3,743,570 to Yang et al., assigned to Crown Zellerbach. According to this patent, polyolefin fibers with high surface area are treated with a hydrophilic colloidal polymer additive containing a cationic polymer such as melamine-formaldehyde and an anionic polymer such as carboxymethyl cellulose. be done. Another method developed for the production of water-dispersible hydrophilic polyolefin pulps involves extruding a mixture of polyolefins with hydrophilic viscosities or additives such as hydrophilic polymers, such as polyvinyl alcohol. It was included. The jetting method used in their production involves dispersing the polyolefin and hydrophilic additives in a liquid that does not act as a solvent for either component at the liquid's normal boiling point, and then pumping the resulting dispersion above atmospheric pressure. to dissolve the polymer and solvent-soluble additives, and then discharge the resulting composition into a region of low temperature and low pressure, usually atmospheric pressure, to form a fibrous product. is generated. A disadvantage of these polyolefin pulps was that when they were blended with wood pulp, the resulting paper product exhibited significantly lower strength than paper made from wood pulp alone. However, some improvement in the strength of papers made by blending polyolefin pulp and wood pulp has been achieved by imparting anionic properties to the polyolefin pulp. For example, in German patent application no. 413922 filed on March 22, 1974, on October 17, 1974,
Among the patents published as No. 2413922, Toray
Industries demonstrated the production of anionic pulp by extruding polyolefins mixed with copolymers of olefin compounds and maleic anhydride or acrylic acid or methacrylic acid. Blends of these pulps and wood pulp provided papers with better tensile strength than papers made without admixture of copolymer components. Additionally, Hercules Incorporated's Belgian Patent No. 850,721 discloses that papers with even improved strength can be prepared from jetted fibrous anionic polyolefin compositions containing carboxyl functionality, such as one polyolefin and one carboxyl. a jetted fibrous composition comprising a mixture of a water-soluble, nitrogen-containing cationic polymer and a water-soluble, nitrogen-containing cationic polymer; It is disclosed that the fibrous product is prepared by modification of the fibrous product by extensive contact with a dilute aqueous solution or dispersion of the formulation with an anionic polymer containing it. This fiber modification process results in the deposition of a nitrogen-containing mixture of cationic and anionic polymers onto the ejected fibers, allowing the initially anionic fibers to bind to the cellulose fibers of the wood pulp. Converts into modified fibers. Nevertheless, although the paper prepared by blending the above-mentioned modified fibers and wood pulp exhibits satisfactory strength, there have been some difficulties associated with the practical use of the paper in some cases. For example, fresh paper from a paper machine is a roll of paper of such size that it typically must be cut to a defined width and rerolled to form a usable form. During the rewinding operation the paper is usually held stationary by a metal guide (guiding device)
The resulting heat and friction weaken some modified polyolefin fibers and cause them to flake off in the form of dust. Much of this dust is carried along with the paper, and when the paper is used for offset printing, for example, it accumulates on the ink rolls, making sure that the ink is properly transported to the printing rolls. This requires frequent cleaning. Now, in accordance with the present invention, a suspension of extruded polyolefin fibers in water is formed, and this suspension contains a water-soluble ionized material that can be converted into submicron-sized hydrated solid particles. adding an aqueous solution of a chemical agent and then adding an ionic precipitant for the chemical agent to the resulting dispersion, thereby uniformly causing precipitation of the hydrated solid particles on the surface of the polyolefin fibers; It has thus been found that it is possible to produce paper with sufficient strength and improved rewinding and printing capabilities. This renders the surface of the fiber essentially uniformly hydrophilic and ionic. As a result, the treated fibers are hydrophilic and water dispersible and are highly sensitive to hydrophilic additives such as starch that are commonly added in the papermaking process. Preferred water-soluble ionized chemical agents of the present invention are rosins and alkali metal salts of modified rosins. In one example of the method of the invention, extruded polypropylene fibers are stirred into suspension in water, and a dilute aqueous solution of a sodium salt of rosin is added to the stirred suspension. After continued stirring, a dilute alum aqueous solution is added to the fiber dispersion, depositing submicron sized hydrated rosin-containing particles on the surface of the polypropylene fibers. The treated fibers can then be separated and stored as a wet cake, or the suspension containing the fibers can be used directly in the papermaking process. Having provided a general overview of embodiments of the invention, the following examples illustrate various embodiments of the invention. All amounts and percentages are by weight unless otherwise specified. Example A A water-soluble nitrogen-containing cationic polymer was prepared from diethylenetriamine, adipic acid and epichlorohydrin. A 0.97 molar amount of diethylenetriamine was placed in a reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. then 1
A molar amount of adipic acid was slowly added to the reaction vessel with stirring. After the acid dissolves in the amine,
The reaction mixture was heated to 170-175°C and held at that temperature for 1.5 hours. The reaction mixture had then become very viscous. The reaction mixture was then cooled to 140° C. and sufficient water was added to obtain a polyamide solution with a solids content of approximately 50%. A polyamide sample isolated from this solution had a concentration of 0.155
It was found to have a reduced specific viscosity of dl/g. Dilute the polyamide solution to 13.5% solids.
It was 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 at a temperature between 70° and 75°C until the Gardner viscosity was between E and F. Enough water was then added to give a solids content of approximately 12.5%, and the solution was cooled to 25°C. Thereafter, the pH of the solution was adjusted to 4.7 with concentrated sulfuric acid. The final product contained 12.5% solids and had a Gardner viscosity of B-C. Example B A water-soluble nitrogen-containing anionic polymer was prepared from acrylamide, acrylic acid, and glyoxal. 890 parts of water were placed in a reaction vessel equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen adapter. Then, 98 parts of acrylamide, 2 parts of acrylic acid, and 1.5 parts of a 10% aqueous solution of cupric sulfate were dissolved in this water. The resulting solution was purged with nitrogen and heated to 70°C, at which temperature a solution of 2 parts of ammonium persulfate in 6.5 parts of water was added. The temperature of the reaction mixture rose 21.5°C during the 3 minutes following the addition of persulfate. When the temperature returns to 76℃, hold it at that temperature for 2 hours,
The reaction mixture was then cooled to room temperature. The resulting solution had a Brookfield viscosity of 54 centipoise at 21°C and contained less than 0.2% acrylamide based on the polymer content. 766.9 parts of the above solution (75.2 parts of amide repeat unit)
39.1 parts of a 40% aqueous solution of glyoxal (15.64 parts as glyoxal, or 0.255 equivalents based on the amide repeat unit) was added to the 40% aqueous solution of glyoxal. PH of the resulting solution
was adjusted to 9.25 by adding 111.3 parts of a 2% aqueous solution of sodium hydroxide. Approximately 20 minutes after adding sodium hydroxide
The Gardner viscosity of the solution increased from A to E within minutes. The reaction was then terminated by adding 2777 parts of water and about 2.6 parts of 40% aqueous sulfuric acid. The resulting solution had a pH of 4.4 and contained 2.2% solids. Example 1 15 grams of air-dried squirted polypropylene was placed in a 1 gallon Waring blender with 1.3 grams of demineralized water and the mixture was agitated moderately. Add 3% (based on the weight of dry fibers) of fully hydrogenated rosin to the resulting suspension with continued stirring.
The size (fully saponified) was added as an aqueous solution and then enough papermaker's grade 10% alum solution was added to lower the pH of the system to about 4.1. The resulting dispersion was then stirred at full speed in a blender for 1 minute and then diluted to 1.5. Another 15 ways to do this
Two preparations were made each time with g fiber samples. In the production of handsheets using treated polypropylene fibers, the combined slurry 1.26 described above is partially dewatered by filtration and then passed through the Noble and Wood cycle.
using neutral tap water as the aqueous phase in a beater.
1.18 g of a 2.5% wood pulp slurry (29.4 g dry fiber consisting of 50% softwood bleached kraft and 50% hardwood bleached kraft), beaten to 750 ml Schopper-Riegler freeness, was added. 40 lb/3000 square feet (0.00649 g/cm ² ) (standard weight) handsheet is made from this 30% polypropylene/70% wood pulp fiber blend using Noble and Wood handsheet equipment. Ivy. After the formed sheet is wet pressed, it is 240~250〓
(115.5-121.1°C) by passing it twice over a drum dryer. Example 2 Polypropylene fibers were made as in Example 1 except that 1% (based on dry fiber weight) of hydrogenated rosin size containing excess alkali was used instead of the hydrogenated rosin size of Example 1. Processed. In the production of handsheets using this fiber, a 1.26 slurry is first added to a binder, which is a 1:5 by weight formulation of the cationic polymer of Example A and the anionic polymer of Example B. Stirred in the presence of 0.63 g. The resulting slurry was then partially dewatered as in Example 1 before being mixed with a standard wood pulp slurry. A handmade sheet was made in the same manner as in Example 1. Example 3 The procedure of Example 2 was repeated except that 3% Utdrozine size was added in place of the 1% Utdrozine size from Example 2. Example 4 3% hydrogenated rosin size of the type used in Example 1 was substituted for the 3% rosin size.
The procedure of Example 3 was repeated except that the size was used. The properties of the handmade sheets of Examples 1 to 4 are shown in Table 1. The data for Example 1 indicate that reasonable values of sheet dry strength were obtained. The data for Examples 2-4 show that the addition of the binder of Example 2 increased the strength values;
The treated fibers therefore appear to be highly sensitive to binders.

[Table] *% binder in the sheet is based on the amount of polypropylene fiber component.

Claims (1)

Claims: 1. Forming a suspension of ejected polyolefin fibers in water and adding to the suspension a water-soluble ionized chemical agent capable of being converted into submicron-sized hydrated solid particles. Add the aqueous solution while stirring,
The ionized chemical agent is selected from the group consisting of rosin, modified rosin, alkali metal and ammonium salts of ethylene-acrylic acid and ethylene-methacrylic acid copolymers and mixtures thereof; adding an ionic precipitant for the ionized chemical agent to the fiber dispersion formed by the process, thereby causing precipitation of the hydrated solid particles on the surface of the polyolefin fibers. A method for producing a polyolefin fiber that is hydrophilic. 2. The method according to claim 1, comprising:
The water-soluble ionized chemical agent is an alkali metal or ammonium salt of rosin or modified rosin. 3. The method according to claim 1, comprising:
The water-soluble ionized chemical agent is an alkali metal salt or ammonium salt of ethylene-acrylic acid or ethylene-methacrylic acid copolymer. 4. The method according to claim 1 or 2, wherein the ionic precipitant is alum. 5. The method according to claim 1 or 2, wherein the ion precipitant is a water-soluble calcium or magnesium salt. 6. The method according to claim 1, comprising:
The ejected polyolefin fibers are polypropylene fibers.