JPH0380166B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a wet paper strength enhancing resin for paper manufacturing that does not hinder repulping of waste paper as much as possible. Paper waste is a waste product in the paper industry that is essentially a loss if it is not collected, repulped, and reused in the paper manufacturing process. It is well known that repulping of broken paper containing agents to enhance wet strength is difficult. Regarding the repulping of broken paper containing such wet paper strength agents, see TAPPI, Vol. 44, pp. 275-280 (1961, 4).
It has been discussed by Schmalz. As a drug for increasing wet strength, there is a cationic water-soluble thermosetting resin obtained by the reaction of polyaminourelene and epichloropidrine. Typical of such resins is the resin shown in U.S. Pat. No. 3,240,664 to Earle, Jr., which is made from a polyalkylene polyamine with tertiary amine groups (e.g., methylbisaminopropylamine) and urea. It is a resin derived from the reaction of polyaminourelene and epichlorohydrin. A cationic water-soluble thermoplastic produced by the reaction of an aminopolyamide (sometimes called polyaminoamide or polyaminopolyamide) made from a _C3 to _C10 saturated dicarboxylic acid and methylbisaminopropylamine with epichlorohydrin. Curable resins are also known, eg Earle,
No. 3,311,594, issued to Jr. U.S. Patent No. 3793279 to Lipowski
No. 3,887,510 to Chan et al.
See also US Pat. No. 3,891,589 to Ray-Chavdhuri. These patents cover the production of aminopolyamides reacted with epichlorohydrin.
The use of diesters derived from _C2 - _C20 saturated dicarboxylic acids is indicated. In U.S. Pat. No. 3,793,279, Lipowski taught the production of cationic wet strength resins by reacting certain chain-extended amine-terminated base polyamides with epichlorohydrin, and treated with this resin. The waste paper from the paper that was
It is stated that waste paper can be more easily recovered than paper treated with other wet strength resins, such as those shown in US Pat. No. 2,926,154 to Keim. Lipowski also notes that acids that decarboxylate, such as oxalic acid, are not suitable for making wet strength resins, and that products made from diethylenetriamine and oxalic acid (subsequently amine-terminated) are not suitable for making wet strength resins. and with or without chain extension) do not produce cationic resins with properties that enhance wet paper strength upon reaction with epichlorohydrin. It is an object of the present invention to provide a method for producing a cationic water-soluble thermosetting resin that provides excellent wet strength to paper, but does not interfere with the ability of the waste paper to be repulped under relatively mild repulping conditions. desired. The present invention provides a cationic water-soluble thermosetting resin consisting of reacting an epihalohydrin, such as epichlorohydrin, in an aqueous solution with an intermediate obtained by the reaction of urea with an amine (e.g. methylbisaminopropylamine). In the manufacturing method of
Methylbisaminopropylamine is mixed with (a) oxalic acid or oxalic acid diester and (b) urea (provided that (a) and (b)
The molar ratio between the two is about 0.1:1 to about 10:1)
This method is characterized by reacting methylbisaminopropylamine and [(a)+(b)] in a molar ratio of about 0.9:1 to about 1.2:1. In the production of the resin of the present invention, which is characterized in that oxalic acid or an oxalic acid diester and urea are brought into contact with methylbisaminopropylamine, the oxalic acid diester preferred for producing an intermediate containing an amide and urelene bond is a lower alkyl ester. Particularly preferred are dimethyl oxalate, diethyl oxalate and dipropyl oxalate. The methylbisaminopropylamine reactive agent - also referred to in the prior art as N-bis(aminopropyl)methylamine - has the formula It has The reaction of oxalic acid or oxalic acid diesters and urea with amines is preferably carried out without a medium, but water,
It is also possible to carry out the reaction by dissolving or dispersing the reactant in a suitable solvent such as alcohol. In a conventional process, the oxalic acid or oxalic acid diester is gradually added to the oxalic acid or oxalic acid diester over a sufficient period of time such that the temperature can be maintained at about 100-125°C to prevent the oxalic acid or oxalic acid diester from decomposing prior to reaction with the amine. added to the amine. The temperature is then raised to about 150 DEG C. to about 200 DEG C. and maintained there for a sufficient time to remove the water produced by the polycondensation and to produce oxalic acid diamide. Sufficient urea is then added to react essentially all of the unreacted methylbisaminopropylamine remaining in the reaction mixture, and the temperature is increased to about 120-240°C, preferably about 150-200°C. The reaction is maintained for about 1/2 to 2 hours in between to complete the reaction. Reaction time varies with temperature and varies inversely with temperature. Usually about 3 to about 7 hours is the time required to complete the reaction of the oxalic acid or oxalic acid diester and urea with the amine. In the aforementioned reaction, the molar ratio of oxalic acid or oxalic acid diester to urea is about 0.1:1 to about 10:1;
Preferably from about 0.2:1 to about 4:1, more preferably from about 0.25:1 to about 4:1. Furthermore, the total amount of methylbisaminopropylamine and acid components (i.e.
The preferred molar ratio (oxalic acid or oxalic acid diester + urea) is from about 0.9:1 to about 1.2:1, more preferably about 1:1. To convert the polyamide-polyurelene intermediate into a cationic water-soluble thermosetting resin, the polyamide-polyurelene is reacted with an epihalohydrin, preferably epichlorohydrin, in an aqueous solution. If the free amine form of the polyamide-polyurelene intermediate has low solubility in water, the reaction is carried out in solution with the intermediate in the form of a water-soluble acid addition salt. Generally, the pH of the intermediate aqueous solution is about 8.5 to about 9.6 before or immediately after the addition of epihalohydrin.
to be attended to. The temperature of the reaction system is such that at 25°C, a solution with a solid content of 25% has a Gardner-Holdt viscosity of approximately E-
F or higher, or a Spence-Spurlin viscosity of at least about 20 seconds or more, preferably about 22 to about 30
The temperature is maintained at about 40°C to about 100°C, preferably about 45°C to 85°C, until the temperature is within seconds. The acid addition salt of the aminopolyamide-polyurelene intermediate is prepared by adding essentially the same stoichiometric equivalent of the tertiary amine of the aminopolyamide-polyurelene intermediate to the aqueous dispersion of the intermediate, e.g. hydrochloric acid), thereby converting essentially all of the tertiary amine to the ammonium salt. Suitable acids for the formation of salts are water-soluble and conventionally known, such as inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and organic acids such as acetic acid. In the reaction of the aminopolyamide-polyurelene with the epihalohydrin, it is preferred to use a sufficient amount of epihalohydrin to convert all tertiary amine groups to quaternary ammonium groups.
from about 1 to about 1.5 per mole of intermediate tertiary amine.
Satisfactory resins can be prepared using moles of epihalohydrin, preferably from about 1.2 to about 1.4 moles. Once the desired viscosity is reached, an additional amount of water is added sufficient to bring the solids content of the resin solution below about 15%, and the product is cooled to a nitrogen temperature of about 25°C. Resin is a reactive group It will include many. The resin contains essentially all reactive groups. an inert group Preferably, it is stabilized against premature gelation by changing to , where X is the halogen of the epihalohydrin and is chlorine when the epihalohydrin is epichlorohydrin. Said stabilization is accomplished by adding a water-soluble acid, preferably a hydrohalic acid such as hydrochloric acid, to the resin solution until essentially all reactive groups have converted to inactive form. This is a pH of about 1-3
This is achieved by adding a sufficient amount of water-soluble acid to maintain the pH. This will convert the reactive groups to an inactive form and stabilize the resin against gelation. If the PH stays at the desired value for about 30 minutes at room temperature (about 25°C), the PH
no longer changes and we can be fairly confident that the resin solution has been stabilized against gelation. In this way, a stable solution having a resin solids content of about 10% to about 50% can be obtained. Hydrohalic acids that can be used in the stabilization method are hydrochloric acid, hydrobromic acid, hydrofluoric acid and hydroiodic acid. When the halide ion concentration in the reaction mixture is sufficiently high (e.g. 0.1N or higher) and the reactivity or nucleophilicity of the acid anion is sufficiently low that the epoxy group is essentially completely converted to halohydrin. A water-soluble acid other than hydrohalic acid can be used. Examples of other water-soluble acids used in this manner include sulfuric acid, nitric acid, phosphoric acid and acetic acid. If necessary, it is also possible to use a mixture of two or more water-soluble acids. Before mixing with paper, this stabilized resin is
The resin solution is reactivated by adjusting the pH of the resin solution to 8 or higher, preferably 10.5 or higher and maintaining the pH at that pH. The preferred PH range is 10.5-12.0. This essentially removes all inert groups. , a crosslinking reactive group It is something that will change again. This PH adjustment is carried out by adding suitable bases, organic or inorganic, such as alkali metal hydroxides and carbonates, calcium hydroxide, benzyltrimethylammonium hydroxide and tetramethylammonium hydroxide. Alkali metals include sodium, potassium, cesium and lithium. The base is preferably added as an aqueous solution. Resins made in the manner described above can be added to the pulp slurry at any point in the wet end of the paper machine. However, prior to use, the stabilized resin must be reactivated as described above to convert the halohydrin groups to epoxy groups. The resins of the present invention have high off-the-
machine) exhibits wet strength and reduces high dry strength. Adequate wet strength for most purposes is
Approximately 0.2 for paper, based on pulp dry weight
% to about 3% resin. The invention is further illustrated by the following examples which illustrate the best mode of the invention. In these examples, unless otherwise noted, measurements of intrinsic viscosity (IV) were made on 2% solutions in 1M ammonium chloride at 25°C; Bruckfield viscosity measurements were
It was run at 25° C. and 60 rpm using a #1 spindle. Example 1 Part A Methylbisaminopropylamine (145.3 g, 1 mole) and urea (48.0 g, 0.8 mole) were added to a reaction vessel equipped with a stirrer, thermometer, heating mantle, nitrogen sparge, and water trap with condenser. and dimethyl oxalate (23.6 g, 0.2 mole).
The contents were gradually heated to 125°C, held at 125°C for 20 minutes, and then heated to 240°C for about 2 hours, collecting methanol and urea byproducts throughout the reaction. After maintaining the reaction mixture at 240°C for about 25 minutes, the temperature was lowered to 130°C, and 97.8 g of 37% HCl aqueous solution and 116 g of water were added.
ml was added and the mixture was thoroughly stirred at 100° C. for about 1 hour to obtain an aqueous solution of the salt formed. If necessary, an aqueous HCl solution was further added to keep the pH below 5.6. A clear yellow viscous solution with a pH of 4.55 and a solids content of 54.5% was obtained. Examination of the solid product by nuclear magnetic resonance ( _C13 NMR) revealed that the product was an aminopolyamide-polyurelene containing 20 mole percent oxamide component. The product is 0.163
He had an IV. Part B Put 52.5 g of the solution from Part A, 160.2 ml of water, and 17.4 g (0.188 mol) of epichlorohydrin into a reaction vessel, and adjust the pH of the solution with 21.1 g of 20% NaOH aqueous solution.
Adjusted to 9.6. The temperature of the resulting solution is 65-70℃.
The viscosity of the solution was monitored. Spence−
When the Spurlin viscosity reached 10 seconds, more 20% NaOH aqueous solution was added to adjust the PH to 8.2. Spence−
When Spurlin viscosity reached 23 seconds, add 40ml of water,
The pH was adjusted to 2 with 37% aqueous HCl. PH2 is about 30
The pH was adjusted periodically until it stopped changing for minutes. The resulting solution had a solids content of 18.7% by weight and a Gardner-Holdt viscosity C at 25°C. Example 2 Part A Methylbisaminopropylamine (1.0 mol) and dimethyl oxalate (0.4 mol) were placed in a reaction vessel equipped with a stirrer, thermometer, heating mantle, nitrogen sparge, and water trap with condenser. The object was gradually heated to 150°C for an hour or so. Maintain the contents at 150°C until most of the methanol byproduct has been collected, then increase the temperature to 90°C.
lowered to ℃. Urea (0.6 mol) was then added to the reaction vessel and the temperature was gradually increased for about 2 hours.
The temperature was raised to 225℃. At this point, the liberation of ammonia had ceased and the reaction appeared to be complete (as a result of titration of the collected ammonia). The temperature of the reaction product was lowered to 130℃, and the product was dissolved in 37.3% HCl aqueous solution.
101.2 g and 120 ml of water were thoroughly mixed to obtain an aqueous solution containing 55.0% of the formed salt with a pH of 3.90. The solid product was tested by _C13 NMR and was an aminopolyamide-polyurelene containing 40 mole percent oxamide component. This product is I.
It was V.0.168. Part B Add 59.7 g of the solution from Part A, 176 ml of water, and 18.8 g (0.203 mol) of epichlorohydrin to a reaction vessel, and adjust the pH of the solution to 9.20 with 21.1 g of 20% NaOH aqueous solution.
tailored to. The temperature of the resulting solution was raised to 65-67°C and the viscosity of the solution was monitored. When the Spence-Spurlin viscosity reached 2.5 seconds, more 20% NaOH aqueous solution was added to adjust the PH to 8.00. Spence−Spurlin
When the viscosity reached 25.0 seconds, add 100ml of water to 37%
The pH was adjusted to 2 with aqueous HCl. PH adjustments were made periodically until PH2 remained constant for approximately 30 minutes.
The resulting solution had a solids content of 13.6% by weight and a Gardner-Holdt viscosity of B at 25°C. Examples 3 and 4 Rayonier bleached kraft pulp and Weyerhaeuser
A 50:50 (by weight) mixture with bleached hardwood kraft pulp was prepared in a Noble and Wood cycle beater to a Canadian Standard freeness of 500 c.c. This pulp was mixed with 10% NaOH.
Aminopolyamide in various amounts (based on the dry weight of the pulp) shown in the table, in accordance with pH 7.5.
Polyurelene-epichlorohydrin resin (made in Examples 1 and 2) was added. The solutions of Examples 1 and 2 were prepared by diluting 20 g of each solution with water to approximately 3% solids prior to use;
Add 1N NaOH and water and mix to reduce the solid resin content to about 2.
% and pH of approximately 11. This pulp was sheeted using a Noble and Wood hand sheet machine to obtain hand sheets having a basis weight of approximately 18.1 kg (40 lbs) per 278.7 m ² (3000 ft ² ) series. The resulting handsheet was wet pressed to a solids content of 33% and then dried in a drum dryer heated with steam at 105° C. for 45 seconds to a moisture content of 3 to 4%. The dry strength of this material was tested, both uncured (after 7 days of natural aging) and cured (30 minutes at 80° C.). The sheets to be tested for wet strength were soaked in distilled water for 2 hours. The results are summarized in a table.

[Table] Example 5 Part A Methylbisaminopropylamine (145.3 g, 1.0 mol) was placed in a reaction vessel equipped with a stirrer, a thermometer, a heating mantle, nitrogen for sparging, and a water trap with a condenser. Heated to 130°C. 70-75 oxalic anhydride (43.2g, 0.48mol)
The resulting oxalic acid solution dissolved in 70 ml of water at 0.degree. C. was added dropwise into the reaction vessel over a period of about 40 minutes while maintaining the contents at 115-130.degree. After the addition was complete, the temperature was raised to 180-184°C for approximately 3 hours or more and maintained there until the water was removed. Then, the temperature of the reaction system was set to 90
℃ and added 31.3 g (0.52 mol) of urea.
The temperature of the mixture was slowly increased to 180-183°C and maintained at this temperature for 1.25 hours, during which time the ammonia was removed. The temperature is then lowered to approximately 150°C and the product is reduced to 37%
It was thoroughly mixed with 98.6 g of aqueous HCl solution and 160 ml of water to obtain an aqueous solution of the salt formed (PH 2.0). The resulting solution had a total solids content of 48.6% by weight.
The product was an aminopolyamide-polyurelene as tested by _C13 NMR. The IV of the product was 0.183. Part B Put 66.0 g of the solution from Part A and 169 ml of water into a reaction vessel, and adjust the pH of the contents with 24.4 g of 20% NaOH aqueous solution.
Adjusted to 8.65. Epichlorohydrin (18.7g,
0.203 mol) was added to make the reaction solid content 20%. The temperature of the resulting solution was raised to 50-52°C and the viscosity of the solution was monitored. When the Spence-Spurlin viscosity reached 25 seconds, 50 ml of water was added and the pH was adjusted to 2 with 37% HCl aqueous solution. The temperature was raised to 65°C and the pH was adjusted periodically until the pH was maintained at 2 for approximately 1 hour. The resulting solution had a total solids content of 15.1% by weight and exhibited a Gardner-Holdt viscosity of C at 25°C. Example 6 Part A A reaction vessel equipped with a stirrer, thermometer, heating mantle, nitrogen sparge, and water trap with condenser was charged with oxalic anhydride (63.0 g, 0.70 mol) and 100 ml of water, and the contents were brought to 110°C. Heated. After adding methylbisaminopropylamine (145.3 g, 1.0 mol) dropwise over 50 minutes, the temperature of the reaction system was raised to 180°C for 2.83 hours or longer and maintained at 180°C until water from polycondensation was removed. did. Next, the temperature of the reaction system was lowered to 50℃, and urea (18.0g,
0.30 mol) was added. Then lower the temperature for 40 minutes
The temperature was increased to 180°C and maintained at 180°C while the by-product ammonia was collected (approximately 35 minutes). Then change the temperature
Lower the temperature to 150℃ and add 102g of 37% HCl aqueous solution and 165.2g of water.
ml and the mixture was stirred well at 90° C. to obtain an aqueous solution of the salt formed. PH2.8, solid content
A clear yellow viscous solution of 45.0%, IV 0.127 was obtained. Part B Put 74.6 g of the solution from Part A and 114 ml of water into a reaction vessel, and pH the contents with 20.5 g of 20% NaOH aqueous solution.
Adjusted to 9.0. Epichlorohydrin (18.0g,
0.195 mol) was added dropwise to reduce the reaction solid content to 25%.
And so. The temperature was increased to 50°C and the viscosity of the solution was followed. When Spence−Spurlin viscosity reaches 30 seconds, water
Add 50ml and adjust the pH to 0.5 with 10g of 37% HCl aqueous solution.
Matched to. Raise the temperature to 65℃, PH for about 30 minutes,
The PH was adjusted periodically until it remained at 2. The resulting solution had a total solids content of 19.0% by weight and exhibited a Gardner-Holdt viscosity of D ⁺ at 25°C. Examples 7, 8 The resin solutions of Examples 5 and 6 were activated using the method set forth in Examples 3 and 4 prior to use. Using the resulting solution, paper sheets were made and tested according to the methods set forth in Examples 3 and 4. The strength properties of the sheet are shown in the table below.

[Table] Examples 9 to 11 Handsheets were prepared according to the method of Examples 3 and 4 using 0.25% of the resins of Examples 2, 5, and 6 based on the pulp dry weight. Uncured handsheet samples were repulped in aqueous NaOH at PH12 at 85°C. Paper sheet repulping
TAPPI method 205m-58 was followed with a mixing speed of 2800 rpm, a pulp consistency of 1.3% and a PH of 12.
Measure the degree of repulping (separation of fibers) and
It is shown as an integer of 6. An integer of 6 indicates essentially complete repulping. The test results are shown in the table below.

[Table] Example 12 Part A A resin polymerization equipped with a stirrer, a thermometer, a heating mantle, nitrogen for purging, and a water trap with a condenser was also used to prepare methylbisaminopropylamine (889.3 g, 6.12 moles) and 50 ml of water. and heated the contents to 135°C. Oxalic anhydride (324.1 g, 3.6 mol) was dissolved in 446 ml of water at 75-80°C, and the resulting oxalic acid solution was added dropwise into the polymerization kettle for 1.5 hours, during which time the contents were heated at 122-136°C. maintained.
After the addition was complete, the temperature was raised to 175° C. for 1.8 hours or more and held there until the water was removed. Next, lower the temperature of the reaction system to 90℃ and add urea (144.1g, 2.4mol)
added. Gradually increase the temperature of the mixture to 190℃,
This temperature was maintained until ammonia evolution ceased. A very viscous yellow transparent aminopolyamide-polyurelene with an IV of 0.206 was obtained, which was poured into an aluminum pan. This process was repeated three times and the resulting products were mixed. Part B Mixed product obtained in Part A (3313
g), 45.2 of the salt formed by mixing well 3806 ml of water and 1780.4 g of 37% HCl aqueous solution with pH 2.8.
% aqueous solution was obtained. Examination by _C13 NMR showed that the product contained 63.7 mol% oxyamide component. The resulting salt had an IV of 0.171. A portion of this salt solution (1366.5 g) and 2096 ml of water were placed in a reaction vessel, and the pH of the solution was adjusted to 9.0 with 366.0 g of a 20% NaOH aqueous solution. Epichlorohydrin (343.4 g, 3.71 mol) was added and the temperature of the resulting solution was raised to 50° C. and the viscosity of the solution was monitored.
Spence−Spurlin viscosity reaches 30 seconds, 37%
The pH was adjusted to 0.4 with an aqueous HCl solution. PH is 2 for 1 hour
The pH was adjusted periodically until the pH remained at . Further, the above step of reacting a portion of the above salt solution with epichlorohydrin in the same manner was repeated 5 times, and the resulting solutions were mixed to give a total solids content of 17.4% by weight, a Gardner-Holdt viscosity of B, and a Bruck field viscosity
A mixed solution with 31.3 cps was formed. C ₁₃ NMR testing of this mixed product showed that 95.8 mol% of the tertiary amine groups were quaternized. Examples 13-15 The mixed resin solution of Example 12 was added to Examples 3 and 4.
Activated before use using the method described in . Paper sheets were made using the resulting solution and the bleached kraft pulp mixture of Examples 3 and 4 (Example 13), Chesapeake unbleached kraft pulp (Example 14), or Manitoba unbleached kraft pulp (Example 15). Manufactured. The strength properties of the sheet are shown in the table below.

【table】

[Table] Amount of resin added

Claims (1)

[Scope of Claims] 1. In the production of a cationic water-soluble thermosetting resin comprising reacting epihalohydrin in an aqueous solution with an intermediate obtained by the reaction of urea and methylbisaminopropylamine, (a) oxalic acid; Or molar ratio of oxalic acid diester and (b) urea 0.1:1 ~
A 10:1 mixture of methylbisaminopropylamine and methylbisaminopropylamine [(a)
+(b)] in a molar ratio of 0.9:1 to 1.2:1. 2. The method according to claim 1, wherein the epihalohydrin is epichlorohydrin. 3. The method according to claim 1 or 2, in which methylbisaminopropylamine is reacted with oxalic acid or oxalic acid diester before reacting with urea. 4. The method according to claim 3, wherein the molar ratio of (a) and (b) is 0.25:1 to 4:1. 5. The method according to claim 3, wherein methylbisaminopropylamine and [(a)+
(b)] in a molar ratio of about 1:1. 6. The method according to any one of claims 1 to 5, wherein (a) is dimethyl oxalate or diethyl oxalate. 7. The method according to any one of claims 1 to 6, wherein after the reaction of the aminopolyamide-polyurelene intermediate and epihalohydrin, the pH of the aqueous solution is adjusted to 3 or less. the
How to maintain PH.