POLYACRYLAMIDE RESIN, PAPERMAKING ADDITIVE, AND PAPER

Abstract

A polyacrylamide resin has at least one kind of a first unit represented by the following formulas (1) to (4) and a second unit represented by the following formula (5).

##STR00001##

(In the above-described formulas (1) to (4), R1 represents a hydrogen atom, a methyl group, an ethyl group, or a benzyl group; R2 and R3 are independent and represent a hydrogen atom, a methyl group, an ethyl group, or a benzyl group; and X represents an anion.)

##STR00002##

(In the above-described formula (5), R4 represents a hydrogen atom or a methyl group and R5 represents a hydrogen atom, an alkali metal ion, or an ammonium ion.)

Claims

1. A polyacrylamide resin having at least one kind of a first unit represented by the following formulas (1) to (4) and a second unit represented by the following formula (5). ##STR00007## (In the above-described formulas (1) to (4), R1 represents a hydrogen atom, a methyl group, an ethyl group, or a benzyl group. R2 and R3 are independent and represent a hydrogen atom, a methyl group, an ethyl group, or a benzyl group; and X represents an anion.) ##STR00008## (In the above-described formula (5), R4 represents a hydrogen atom or a methyl group and R5 represents a hydrogen atom, an alkali metal ion, or an ammonium ion.)

2. The polyacrylamide resin according to claim 1 having the first unit represented by the above-described formula (3) or the above-described formula (4) and having X representing Cl.sup.−.

3. A papermaking additive containing; the polyacrylamide resin according to claim 1.

4. Paper containing: the polyacrylamide resin according to claim 1.

Description

EXAMPLES

[0148] The present invention will hereinafter be described based on Examples and Comparative Examples. The present invention is however not limited by the following Examples. All designations of “part” or “parts” and “%” mean part or parts by mass and % by mass, respectively, unless otherwise particularly specified. The specific numerical values in mixing ratio (content ratio), property value, and parameter used in the following description will be replaced with upper limits (numerical values defined as “or less” or “below”) or lower limits (numerical values defined as “or more” or “above”) of corresponding numerical values in mixing ratio (content ratio), property value, and parameter described in the above-described

DESCRIPTION OF EMBODIMENTS

Example 1

[0149] As a part of a polymerization component, 15 mol % of the total charged amount of the polymerization component described in Table 1 was prepared and diluted with tap water so that the concentration thereof was 10 mass %.

[0150] Next, the obtained solution was charged in a 500 -mL separable flask.

[0151] Next, sulfuric acid was added to the solution and the pH thereof was adjusted to about 2.5.

[0152] Thereafter, while nitrogen was continued being blown into the solution, ammonium persulphate (APS), as a polymerization initiator, was added dropwise at 90° C. to initiate polymerization and next, the remaining portion (85 mol %) of the polymerization component was added dropwise.

[0153] After the completion of the dropping of the remaining portion of the above-described polymerization component, the ammonium persulphate (APS), as a polymerization initiator, was added until the appropriate viscosity (about 5000 to 10000 mpa.Math.s) and the reaction was continued around 90° C.

[0154] Thereafter, sodium sulfite (Na.sub.2SO.sub.3), as a polymerization terminator, and dilution water were added to be cooled, thereby obtaining an aqueous solution of a polyacrylamide resin.

[0155] The aqueous solution had the solid content concentration of 20.1 mass %.

[0156] Also, the viscosity at 25° C. of the aqueous solution and the weight average molecular weight (Mw) of the polyacrylamide resin were measured by the following method. The results are shown in Table 1.

[0157] <Measurement of Viscosity at 25° C.>

[0158] The viscosity at 25° C. was measured in accordance with JIS K 7117-1 (in 1999) using a B-type viscometer (rotor No. 3, 12 rpm) (TVB-10 viscometer, manufactured by TOKI SANGYO CO., LTD.).

[0159] <Measurement of Weight Average Molecular Weight (Mw) with Gel Permeation Chromatography>

[0160] A sample was dissolved in a phosphate buffer having a pH of 7 and the concentration of the sample was adjusted to 1.0 g/L to be measured with gel permeation chromatography (GPC). The weight average molecular weight (Mw) of the sample was calculated from the obtained chromatogram (chart). The measurement device and the measurement conditions are shown below.

[0161] Device: part number TDA-302 (manufactured by Viscotek)

[0162] Column: part number TSKgel GMPW.sub.XL (manufactured by Tosoh Corporation)

[0163] Moving Phase: phosphate buffer

[0164] Column Flow Rate: 0.8 mL/min

[0165] Concentration of Sample: 1.0 g/L

[0166] Injection Rate: 500 !IL

Examples 2 to 8 and Comparative Examples 1 to 6

[0167] Each of the aqueous solutions of the polyacrylamide resin was obtained in the same manner as that in Example 1 except that the mixing formulation shown in Tables 1 to 2 was used. Also, the viscosity at 25° C. of each of the aqueous solutions and the weight average molecular weight (Mw) of each of the polyacrylamide resins were measured in the same manner as that in Example 1. The results are shown in Tables 1 to 2.

Examples 9 to 10

[0168] As a part of the polymerization component, 15 mol % of the total charged amount of the polymerization component described in Table 1 was prepared and diluted with tap water so that the concentration thereof was 10 mass %.

[0169] Next, the obtained solution was charged in a 500 -mL separable flask.

[0170] Next, the sulfuric acid was added to the solution and the pH thereof was adjusted to about 2.5.

[0171] Thereafter, while the nitrogen was continued being blown into the solution, the ammonium persulphate (APS), as the polymerization initiator, was added dropwise at 90° C. to initiate the polymerization and next, a mixed solution of the remaining portion (85 mol %) of the polymerization component and glyoxylic acid that was 3.6 mol % with respect to the polymerization component was added dropwise.

[0172] After the completion of the dropping of the remaining portion of the above-described polymerization component, the ammonium persulphate (APS), as the polymerization initiator, was added until the appropriate viscosity (about 5000 to 10000 mPa.Math.s) and the reaction was continued around 90° C.

[0173] Thereafter, the sodium sulfite (Na.sub.2SO.sub.3), as the polymerization terminator, and the dilution water were added to be cooled, thereby obtaining the aqueous solution of the polyacrylamide resin.

[0174] Each of the aqueous solutions had the solid content concentration of 20.5 mass %. Also, the viscosity at 25° C. of each of the aqueous solutions and the weight average molecular weight (Mw) of each of the polyacrylamide resins were measured in the same manner as that in Example 1. The results are shown in Table 1.

Example 11

[0175] As a part of the polymerization component, 15 mol % of the total charged amount of the polymerization component described in Table 1 was prepared and diluted with tap water so that the concentration thereof was 10 mass %.

[0176] Next, the obtained solution was charged in a 500 -mL separable flask.

[0177] Next, the sulfuric acid was added to the solution and the pH thereof was adjusted to about 2.5.

[0178] Thereafter, while the nitrogen was continued being blown into the solution, the ammonium persulphate (APS), as the polymerization initiator, was added dropwise at 90° C. to initiate polymerization and next, the remaining portion (85 mol %) of the polymerization component was added dropwise.

[0179] After the completion of the dropping of the remaining portion of the above-described polymerization component, the ammonium persulphate (APS), as the polymerization initiator, was added until the appropriate viscosity (about 5000 to 10000 mpa.Math.s) and the reaction was continued around 90° C.

[0180] Thereafter, the sodium sulfite (Na.sub.2SO.sub.3), as the polymerization terminator, and the dilution water were added and next, glyoxylic acid that was 1.8 mol % with respect to the polymerization component was added to continue the reaction at 90° C. for one hour.

[0181] Thereafter, the obtained solution was cooled, thereby obtaining an aqueous solution of the polyacrylamide resin.

[0182] The aqueous solution had the solid content concentration of 20.9 mass %. Also, the viscosity at 25° C. of the aqueous solution and the weight average molecular weight (Mw) of the polyacrylamide resin were measured in the same manner as that in Example 1. The results are shown in Table 1.

TABLE-US-00001 TABLE 1 No. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Mixing Polymerization AM 90.4 90.2 89.9 89.7 89.4 89.9 Formulation Component Acrylic Acid — — — — — — [mol %] Itaconic Acid — — — — — — AmGlyA 3.6 3.6 3.6 3.6 3.6 3.6 DM — — — — — — N-methyldiallylamine — — — — — 5.5 DADMAC 5.5 5.5 5.5 5.5 5.5 — Sodium Methallylsulfonate 0.5 0.7 1.0 1.2 1.5 1.0 Addition Amount of Glyoxylic Acid [mol %] — — — — — — Property Weight Average Molecular 1500000 4000000 4500000 6000000 7500000 4500000 Weight Solid Content 20.1 20.3 20.3 20.2 20.6 20.8 Concentration (%) Viscosity (mPa .Math. s) 6800 7200 5800 6500 7300 6400 Evaluation Internal Bond [mJ] 169 171 186 193 184 179 Water Filtering Property 530 540 555 560 555 520 No. Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Mixing Polymerization AM 90.2 90.2 93.5 91.7 91.7 Formulation Component Acrylic Acid 1.8 — — — — [mol %] Itaconic Acid — 1.8 — 1.8 1.8 AmGlyA 1.8 1.8 — — — DM — — — — — N-methyldiallylamine — — — — — DADMAC 5.5 5.5 5.5 5.5 5.5 Sodium Methallylsulfonate 0.7 0.7 1.0 1.0 1.0 Addition Amount of Glyoxylic Acid [mol %] — — 3.6 1.8 1.8 Property Weight Average Molecular 4500000 4500000 4500000 4500000 4500000 Weight Solid Content 20.4 20.5 20.5 20.7 20.9 Concentration (%) Viscosity (mPa .Math. s) 6000 6900 6300 5600 7100 Evaluation Internal Bond [mJ] 198 209 195 212 207 Water Filtering Property 540 550 560 555 555

TABLE-US-00002 TABLE 2 No. Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 Comp. Ex. 4 Comp. Ex. 5 Comp. Ex. 6 Mixing Polymerization AM 90.6 90.4 90.5 90.3 90.2 89.9 Formulation Component Acrylic Acid 3.6 3.6 3.6 3.6 — — [mol %] Itaconic Acid — — — — — — AmGlyA — — — — 3.6 3.6 DM 5.5 5.5 — — 5.5 5.5 N-methyldiallylamine — — 5.5 5.5 — — DADMAC — — — — — — Sodium 0.3 0.5 0.4 0.6 0.7 1.0 Methallylsulfonate Addition Amount of Glyoxylic — — — — — — Acid [mol %] Property Weight Average 2000000 4500000 2000000 4500000 2000000 4500000 Molecular Weight Solid Content 20.4 20.7 20.9 20.5 20.8 20.9 Concentration (%) Viscosity (mPa .Math. s) 5200 5900 6800 6200 6300 7000 Evaluation Internal Bond [mJ] 139 141 144 146 150 150 Water Filtering Property 485 490 480 480 485 495

[0183] The abbreviations in the Tables are shown below.

[0184] AM: acrylamide

[0185] DM: dimethylaminoethyl methacrylate

[0186] DADMAC: diallyldimethylammonium chloride

[0187] AmGlyA: acrylamide-N-glycolic acid

[0188] <Evaluation>

[0189] (1) Internal Bond

[0190] By using each of the aqueous solution of the polyacrylamide resin obtained in Examples and Comparative Examples, paper was produced by the following method.

[0191] That is, first, a pulp material (bleached kraft pulp (BKP) (hardwood pulp (LBKP)/softwood pulp (NBKP)=50/50, Canadian Standard Freeness (CSF: water filtering property)=380 mL) wad added to a 1 L-stainless tube so as to obtain 6.25 g in an absolute dry condition and diluted with tap water so that the concentration of the pulp slurry was 3.0 mass %.

[0192] Next, the obtained pulp slurry was stirred at 400 rpm and an aqueous solution of the polyacrylamide resin that was diluted to 1.2 mass % was added thereto one minute after the start of the stirring. The addition amount of the aqueous solution was adjusted so that the solid content thereof was 1.5 mass % with respect to the absolute dry pulp mass.

[0193] Two minutes later, the obtained solution was diluted with tap water (pH of 6.5, total hardness of 135 ppm) so that the concentration of the pulp slurry was 1.0 mass %, and three minutes later, the stirring was terminated and papermaking was performed, thereby obtaining wet paper (100 g/m.sup.2).

[0194] Thereafter, the obtained wet paper was pressed at room temperature and then, dried at 110° C. for three minutes with a drum dryer. In this manner, handmade paper (100 g/m.sup.2) was obtained.

[0195] By using the obtained paper, the paper strength (internal bond [mJ]) was evaluated by the following method.

[0196] That is, in accordance with the standard No. 18-2 “Paper and paperboard-internal bond strength test method-Part 2: Internal Bond Tester method” described in the 2000 edition of JAPAN TAPPI paper pulp test method, the internal bond (IB) of the paper was measured.

[0197] The results are shown in Table 1.

[0198] (2) Water Filtering Property

[0199] The water filtering property in the production step of the paper was evaluated in the following steps.

[0200] That is, the pulp slurry to which the above-described aqueous solution of the polyacrylamide resin was added was diluted with tap water in which the pH thereof was adjusted to 7 so that the concentration of the pulp slurry was 0.3%. By using 1000 mL thereof, CSF (ml) was measured in accordance with JIS P 8121-2 (in 2012).

[0201] The results are shown in Table 1.

[0202] <Consideration>

[0203] A presence or absence of the first polymerizable compound and the second polymerizable compound in each of the polymerization components in Comparative Examples 2, 4, and 6 and Example 6 in which the polyacrylamide resin having a weight average molecular weight of 4500000 was produced, and the evaluation results thereof are shown in Table 3.

TABLE-US-00003 TABLE 3 Second Water First Polymerizable Compound Polymerizable Filtering No. (N-methyldiallylamine) Compound (AmGlyA) IB [mJ] Property Comp. Ex. 2 Absence Absence 141 490 Comp. Ex. 4 Presence Absence 146 480 Comp. Ex. 6 Absence Presence 150 495 Ex. 6 Presence Presence 179 520 Comp. Ex. 4-Comp. Ex. 2 Presence-Absence Absence-Absence 5 −10 Comp. Ex. 6-Comp. Ex. 2 Absence-Absence Presence-Absence 9 5 Ex. 6-Comp. Ex. 4 Presence-Absence Presence-Absence 33 40 Ex. 6-Comp. Ex. 6 Presence-Absence Presence-Absence 29 25

[0204] As is clear from Table 3, in contrast to Comparative Example 2 in which the polymerization component did not contain both of the first polymerizable compound and the second polymerizable compound, in Comparative Example 4 in which the first polymerizable compound was added to the polymerization component, the value of the internal bond was increased by 5 and the value of the water filtering property was decreased by 10.

[0205] Meanwhile, in contrast to Comparative Example 2 in which the polymerization component did not contain both of the first polymerizable compound and the second polymerizable compound, in Comparative Example 6 in which the second polymerizable compound was added to the polymerization component, the value of the internal bond was increased by 9 and the value of the water filtering property was increased by 5.

[0206] On the other hand, in contrast to Comparative Example 4 in which the polymerization component contained the first polymerizable compound and did not contain the second polymerizable compound, in Example 6 in which the second polymerizable compound was added to the polymerization component, the value of the internal bond was increased by 33 and the value of the water filtering property was increased by 40.

[0207] In contrast to Comparative Example 6 in which the polymerization component contained the second polymerizable compound and did not contain the first polymerizable compound, in Example 6 in which the first polymerizable compound was added to the polymerization component, the value of the internal bond was increased by 29 and the value of the water filtering property was increased by 25.

[0208] In this way, a difference between Comparative Example 4 and Example 6 (internal bond of +33, water filtering property of +40) and a difference between Comparative Example 6 and Example 6 (internal bond of +29, water filtering property of +25) are larger than the total value of a difference between Comparative Example 2 and Comparative Example 4 (internal bond of +5, water filtering property of −10) and a difference between Comparative Example 2 and Comparative Example 6 (internal bond of +9, water filtering property of +5).

[0209] That is, from the above-described results, the synergistic effect was confirmed in the first polymerizable compound and the second polymerizable compound.

[0210] While the illustrative embodiments of the present invention are provided in the above description, such is for illustrative purpose only and it is not to be construed as limiting the scope of the present invention. Modification and variation of the present invention that will be obvious to those skilled in the art is to be covered by the following claims.

INDUSTRIAL APPLICABILITY

[0211] The polyacrylamide resin, the papermaking additive, and the paper of the present invention are preferably used in news print paper, ink jet paper, thermal recording body paper, pressure-sensitive recording body paper, wood free paper, paperboard, coated paper, household paper, and the like.