JP2761891B2 - Papermaking sizing composition and sizing method - Google Patents

Description

The present invention relates to a sizing composition for papermaking and a sizing method, and more particularly, to a substituted cyclic dicarboxylic acid having excellent dispersion stability and excellent sizing effect. The present invention relates to an anhydrous paper sizing composition and a sizing method using the same.

[Conventional technology]

2. Description of the Related Art Conventionally, sizing has been performed in ordinary paper and paperboard papermaking methods in order to provide these papers with functions such as size, waterproofness, and water resistance. As this sizing method, acidic sizing has been performed in which the sizing is performed in an acidic range of pH 4.5 to 6.5 using a rosin sizing agent having a carboxyl group and a sulfate band. On the other hand, in recent years, a neutral sizing agent has been used for the purpose of using inexpensive calcium carbonate as a filler, using waste paper or waste paper containing calcium carbonate, closing papermaking water, and imparting permanent storage properties of paper. A so-called neutral sizing method for sizing in a neutral to weakly alkaline region having a pH of 6.5 to 9 has attracted attention.

It is known to use an aqueous emulsion of a substituted succinic anhydride as a neutral sizing agent, and emulsify the substituted succinic anhydride using a cationized starch, a certain polymer and / or an emulsifier to form an aqueous emulsion. The methods used are known. (Special Publication 39-2305, Special Publication Akira
53-36044, JP-A-58-45731).

Aqueous emulsions of substituted succinic anhydrides prepared by these methods have poor dispersion stability, such as causing two-phase separation over time, or form aggregates, have poor resistance to hydrolysis, and precipitate hydrolysates. Or These are adhered to a press roll or the like in a white water circulation system in a paper making process, and cause operational trouble. Furthermore, the size effect is reduced due to poor emulsifiability during short-term storage.

The present inventors have proposed in JP-A-61-34298 a sizing dispersion for papermaking comprising an aqueous emulsion of a substituted cyclic dicarboxylic anhydride having improved dispersion stability.

[Problems to be solved by the invention]

However, the performance of the paper sizing agent dispersion according to this proposal cannot be said to be sufficient, and it has been desired to further improve the quality, performance and effect.

That is, in order to effectively function as a sizing agent for papermaking, it is necessary for the sizing agent to yield on the paper during papermaking. The yield of the sizing agent is affected by the ionicity and the amount of other concomitant chemicals used in papermaking, such as paper strength agents and retention aids. It is necessary to select the ionicity of the protective colloid used when preparing the sizing agent dispersion. JP-A-61-34298 proposes the use of an oil-in-water surfactant and a cationic or amphoteric poly (meth) acrylamide during emulsification as a papermaking sizing agent with improved stability. However, there is a limit in the range of choice of ionicity of cationic or amphoteric poly (meth) acrylamide used as protective colloid. The oil-in-water surfactant used in combination with emulsification is essentially a size inhibitor, and it is desirable to minimize the addition of these surfactants.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve the above problems, and as a result, have reached the present invention.

The present invention relates to (a) a substituted cyclic dicarboxylic anhydride represented by the following general formula (I): (Wherein, R is an alkyl group, alkenyl group, aralkyl group, or aralkyl group having 5 or more carbon atoms, and n is 2 to 3
Represents an integer. (B) a water-soluble polymer obtained by polymerizing or copolymerizing a vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms, and (b) based on 100 parts by weight of the compound (a)
A water-soluble polymer of 1 to 100 parts by weight. In this case, the alkyl mercaptan having 6 to 22 carbon atoms in the above (b) is preferably present in an amount of 0.01 to 10 mol% based on the vinyl monomer, and the vinyl monomer is acrylamide, or acrylamide and a cationic vinyl monomer. Or acrylamide and an anionic vinyl monomer, or acrylamide, an anionic vinyl monomer and a cationic vinyl monomer.

The papermaking sizing composition of the present invention has excellent dispersion stability and excellent sizing effect without using an emulsifier such as another surfactant. This is presumably because the water-soluble polymer obtained by polymerizing the vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms acts as an emulsifier and a protective colloid.

The substituted cyclic dicarboxylic anhydride used in the present invention is a substituted cyclic dicarboxylic acid having an alkyl group, an alkenyl group, an aralkyl group or an aralkenyl group represented by the general formula (I) and having 5 or more carbon atoms, preferably 5 to 24 carbon atoms. Is anhydrous,
Specifically, hexadecyl succinic anhydride, octadecyl succinic anhydride, hexadecenyl succinic anhydride, heptadecenyl succinic anhydride, octadecenyl succinic anhydride, tetrapropenyl succinic anhydride And triisobutenyl succinic anhydride, 1-methyl-2-pentadecenyl succinic anhydride, and the like, and substituted glutaric anhydride can be used in place of substituted succinic anhydride.

The alkyl mercaptan having 6 to 22 carbon atoms used in the present invention may be linear or branched, and the raw material of the alkyl group may be a natural one or an artificially produced one such as cracking of low-polymerized paraffin of ethylene or propylene. May be used. For example, normal octyl mercaptan, normal dodecyl mercaptan, tertiary decyl mercaptan, normal hexadecyl mercaptan, normal octadecyl mercaptan and the like can be mentioned.
Of these, normal octyl mercaptan and normal dodecyl mercaptan are particularly preferred.

In the presence of an alkyl mercaptan having 6 to 22 carbon atoms, as a vinyl monomer for a polymerization or copolymer used as a raw material, the following various monomers can be used.

For example, cationic vinyl monomers include (mono- or di-alkyl) amino (hydroxy) alkyl (meth) acrylate, mono- or di-alkylaminoalkyl (meth) acrylamide, vinylpyridine, vinylimidazole, diallylamine and the like. And salts of these inorganic or organic acids, or quaternary ammonium salts thereof.

Further, (meth) acrylamide, N, N-dimethylacrylamide, hydroxypropyl (meth) acrylate, and the like can be used as the nonionic vinyl monomer.

Examples of the anionic vinyl monomer include monomers having a carboxylic acid group such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, vinyl sulfonic acid, (meth) allyl sulfonic acid,
-Acrylamide-2-methylpropanesulfonic acid, a monomer having a sulfonic acid group such as sulfonated styrene,
Alternatively, a monomer having a phosphate group such as a hydroxyalkyl (meth) acrylate phosphate can be used. Further, as a hydrophobic vinyl monomer, styrene or a derivative thereof, an alkyl (meth) acrylate,
Vinyl esters such as (meth) acrylonitrile, vinyl acetate or vinyl propionate, and methyl vinyl ether can be used, but the hydrophobic monomer is preferably 25% by weight or less of the monomer units constituting the polymer.

Among these vinyl monomers, preferably a combination of acrylamide or acrylamide and a cationic vinyl monomer, or a combination of acrylamide and an anionic vinyl monomer, and more preferably acrylamide, a cationic vinyl monomer and an anionic vinyl monomer It is a combination.

The amount of the alkyl mercaptan having 6 to 22 carbon atoms used in the present invention is 0.01 to 10 mol% based on the vinyl monomer involved in polymerization or copolymer, and is preferably
0.05 to 2 mol%.

When the amount is less than the above range, a stable emulsion cannot be obtained, and when the amount exceeds the above range, it remains without being consumed at the time of polymerization or copolymerization reaction, and may cause stains on a paper making apparatus. In addition, the cost increases, and the dispersion stability and the size effect are adversely affected.

The polymerization or copolymerization reaction of the vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms can be performed according to a conventionally known method.

For example, it can be obtained by performing a polymerization reaction in a lower alcohol solvent such as methanol, ethanol, isopropyl alcohol or the like or a mixed solvent of lower alcohol and water in the presence of a radical polymerization catalyst and, after completion of the polymerization reaction, distilling off alcohol. Examples of the radical polymerization catalyst include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, a redox polymerization catalyst obtained by combining these persulfates and a reducing agent, or 2,2′-azobis- (2-amidinopropane). And azo catalysts such as dihydrochloride and 2,2'-azobisisobutyronitrile. If necessary, a known chain transfer agent may be appropriately used in combination.

The viscosity of the resulting polymer or copolymer is 20% by weight
An aqueous solution having a viscosity of 10 to 5,000 centipoise (however, measured at 25 ° C., Brookfield viscometer at 60 revolutions per minute) can be used, and one having the above viscosity of 50 to 1,000 centipoise is particularly preferable. When a polymer or copolymer having a viscosity outside this range is used, the dispersion stability of the papermaking sizing composition of the present invention tends to be poor.

A water-soluble polymer obtained by polymerizing a vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms is 1 to 100 parts by weight of the substituted cyclic dicarboxylic acid anhydride represented by the general formula (I). 100 parts by weight, preferably 5
It is good to use in a proportion of ~ 50 parts by weight. If the amount is less than 1 part by weight, the emulsifiability is poor, and the dispersion stability of the sizing composition for papermaking is lost. If the amount exceeds 100 parts by weight, the sizing effect is adversely affected.

In addition, the sizing composition for papermaking of the present invention may be, if necessary, a cationic, anionic or amphoteric acrylamide polymer obtained by polymerizing in the absence of a cationized starch or an alkyl mercaptan having 6 to 22 carbon atoms. Dispersing agents such as polymeric protective colloids, anionic dispersants such as lignin sulfonate, naphthalene sulfonate-formaldehyde condensate, nonionic dispersants such as sorbitan ester, and other surfactants. It can be used to the extent that stability is not impaired.

The sizing composition for papermaking of the present invention is obtained by polymerizing a vinyl monomer in the presence of a substituted cyclic dicarboxylic anhydride represented by the general formula (I) according to the present invention and an alkyl mercaptan having 6 to 22 carbon atoms. After mixing with the water-soluble polymer obtained in the laboratory, the mixture is emulsified using a universal homogenizer (manufactured by Nippon Seiki Seisakusho), a homomixer, an ultrasonic emulsifier or a household mixer. Alternatively, it can be obtained by emulsifying using a certain type of emulsifying apparatus.

The papermaking sizing composition of the present invention thus obtained has a particle size of the dispersed phase of 0.3 to 5.0 μm, and can exhibit excellent dispersion stability and excellent sizing effect.

The sizing composition for papermaking of the present invention has the advantage that the dispersion stability is excellent even if the ionicity of the water-soluble polymer (b) is nonionic, cationic, anionic or amphoteric. This enables the ionicity to be appropriately selected and adjusted according to the type and amount of the ionicity of the other additives to be used when used as a sizing composition for papermaking.

The sizing composition for papermaking of the present invention can be used for both an internal sizing composition and a surface sizing composition.

In using the sizing composition for papermaking of the present invention, the aqueous dispersion of pulp, 0.01 wt.
-4% by weight, preferably 0.05-2% by weight.

Pulp raw materials include bleached or unbleached chemical pulp such as kraft pulp or sulfite pulp, groundwood pulp,
Either bleached or unbleached high-yield pulp such as mechanical pulp or thermomechanical pulp, or used paper pulp such as used newspaper, magazine used paper, corrugated cardboard, or deinked used paper can be used.

Fillers, dyes, dry paper strength improvers, wet paper strength improvers, additives such as retention aids may also be used if necessary,
In addition, starch, polyvinyl alcohol, a dye, a coating color, a surface sizing agent, an anti-slip agent and the like may be applied as needed using a size press, a gate roll coater, a bill blade coater, a calender or the like.

The papermaking sizing agent of the present invention exhibits excellent dispersion stability,
Since the size effect is also excellent, paper having excellent paper quality can be made.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to only these examples. In the following Examples and Comparative Examples, “%” means “% by weight of solid content” unless otherwise specified, and “parts” means “parts by weight”. The amounts of fillers and chemicals are expressed in terms of solid weight% based on the dry pulp weight.

Example 1 In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, 7.78 g of dimethylaminoethyl methacrylate, 225.2 g of a 50% acrylamide aqueous solution, 2.15 g of itaconic acid, and 1.00 g of normal dodecyl mercaptan , 163.1 g of ion-exchanged water and 214.4 g of isopropyl alcohol, and adjusted to pH 4.0 with a 20% aqueous sulfuric acid solution.

Subsequently, nitrogen gas was introduced while stirring to remove oxygen, and the temperature was raised to 60 ° C. At 60 ° C., 3.77 g of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Then 78
After raising the temperature to 78 ° C. and maintaining at 78 ° C. for 1.5 hours, 1.13 g of a 5% ammonium persulfate aqueous solution was added. After maintaining the same temperature for another hour, 200 g of ion-exchanged water was added, and distillation of isopropyl alcohol was started. Two hours after the start of the distillation, 278.5 g of a mixed distillate of isopropyl alcohol and water was obtained, and the distillation was completed. 78.5 g of ion-exchanged water was added to the obtained polymerization product, and the Brookfield viscosity (hereinafter referred to as viscosity) measured at a non-volatile content of 20.3% and a rotation of 60 rpm at 25 ° C./min.
An aqueous copolymer solution P-1 having a viscosity of 320 centipoise (hereinafter referred to as cps) and a pH of 4.3 was obtained.

Next, 123 parts of the obtained aqueous copolymer solution P-1 and water 27
After sufficiently mixing the parts, 100 parts by weight of hexadecenyl succinic anhydride was added, and the mixture was emulsified using a universal homogenizer (manufactured by Nippon Seiki Seisakusho) at 10,000 rpm for 30 seconds, and then averaged. An aqueous emulsion having a particle size of 0.58 μm was obtained. This was used as paper sizing composition E-1, diluted with water so that the concentration of hexadecenyl succinic anhydride became 1%, and used for the subsequent tests.

Examples 2 to 5 Polymerization was carried out in the same manner as in Example 1 except that the type of mercaptan and the composition of the vinyl monomer were changed to those shown in Table 1, and copolymer aqueous solutions P-2 to P-5 were obtained. The amount of isopropyl alcohol for adjusting the viscosity was appropriately changed each time.

Next, the same operation as in Example 1 was performed at a mixing ratio of hexadecenyl succinic anhydride / copolymer aqueous solution as shown in Table 2 to obtain paper sizing compositions E-2 to E-5. Obtained. The obtained sizing composition for papermaking was diluted with water so that the concentration of hexadecenyl succinic anhydride became 1%, and subjected to the subsequent tests.

Comparative Examples 1-3 Copolymer aqueous solutions RP-1 to RP in the same manner as in Examples 2 to 5.
-3, and then sizing compositions RE-1 to RE-3 for papermaking.
The sizing composition for papermaking was further diluted with water so that the concentration of hexadecenyl succinic anhydride became 1%, and subjected to the subsequent tests.

Comparative Example 4 After cooking, 150 parts of a 10% by weight cationized starch (Kate 15 manufactured by Oji National Co., Ltd.) and 10 parts of hexadecenylsuccinic anhydride were subjected to 15,000 rpm using a universal homogenizer. An emulsifying operation was performed for 3 minutes to obtain an aqueous emulsion having an average particle size of 0.98 μm.
This was designated as paper sizing composition RE-4, to which water was added and diluted with water so that the concentration of hexadecenyl succinic anhydride became 1%, and used for the subsequent experiments.

The composition and physical properties of the aqueous copolymer solutions P-1 to P-5 and RP-1 to RP-3 used in Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 1, and the obtained sizing agent for papermaking. Compositions E-1 to E-
Table 2 shows the blending and physical properties of No. 5 and RE-1 to RP-4.

The abbreviations of mercaptans and vinyl monomers used in Table 1 are as follows.

M-1 n-dodecyl mercaptan M-2 n-octyl mercaptan M-3 tert-dodecyl mercaptan M-4 n-hexadecyl mercaptan M-5 n-octadecyl mercaptan M-6 n-butyl mercaptan M-7 thiophenol C- Reference Signs List 1 dimethylaminoethyl methacrylate C-2 quaternized product of the above methyl chloride C-3 dimethylaminopropyl acrylamide C-4 dimethylaminopropyl methacrylamide A-1 itaconic acid A-2 maleic acid A-3 acrylic acid Next, sizing was performed using the sizing composition for papermaking obtained above, and the effect was tested.

That is, a pulp slurry having a concentration of 2.4% [BKPL / N = 8 /
2, Canadian Standard Freeness 365ml] and Light Calcium Carbonate (Tamapearl 121 Okutama Kogyo) 3
After adding 0% and stirring for 2 minutes, 0.9% of cationized starch (Kate F, manufactured by Oji National Co., Ltd.) was sequentially added, and the mixture was further stirred for 2 minutes.

Then, after diluting the pulp slurry concentration to 0.24%, the sizing compositions for papermaking obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were used for E-1 to E-5 and the sizing composition for papermaking RE-1. ~
After adding 0.1% of RE-4 and 0.02% of a retention aid (High Reten 104, manufactured by Dick Hercules), stirring for 1 minute, weighing 80 g / m ² with a hand-making device manufactured by Noble & Wood. Wet paper was obtained. The papermaking pH was 8.0.

The wet paper was pressed until the moisture content became 59.0%, and then dried at 80 ° C. for 70 seconds with a drum dryer. Immediately after drying, paper having a water content of 4.0% was obtained. Using the paper immediately after drying, the degree of Stekigt sizing was measured according to JIS P-8122. Table 3 shows the results.

Paper sizing compositions E-1 to E-5 and RE-1 to RE-4 obtained in Examples 1 to 5 and Comparative Examples 1 to 4 for the purpose of examining the dispersion stability of the paper sizing composition. Was kept at 32 ° C. for 4 hours, and then the average particle size was measured. The results are shown in Table 4.

As described above, Examples 1 to 5 and Comparative Examples 1 to 4 show that the sizing composition for papermaking of the present invention has excellent dispersion stability and shows an excellent sizing effect.

Effects of the Invention According to the present invention, a substituted cyclic dicarboxylic acid anhydride represented by the general formula (I) is obtained by polymerizing or copolymerizing a vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms. The sizing composition for papermaking is excellent in dispersion stability and sizing effect, and a sizing method using the same can also exhibit an excellent sizing effect.

Further, the sizing composition for papermaking of the present invention has the advantage that, even if the ionicity of the water-soluble polymer is nonionic, cationic, anionic or amphoteric, the dispersion stability is excellent, Is appropriately selected according to the type and amount of the ionicity of the additive used in combination with the other,
Allows you to adjust.

Further, the sizing composition for papermaking of the present invention has excellent dispersion stability and excellent sizing effect without using an emulsifier such as another surfactant.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masatomi Ogawa 17-2 Yawata Kaigandori, Ichihara City, Chiba Prefecture Inside Dick Hercules Co., Ltd. (56) References JP-A-58-45731 (JP, A) JP-A-61-34298 (JP, A) JP-A-53-58006 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) D21H 11/00-27/42

Claims (4)

(57) [Claims] (1) a substituted cyclic dicarboxylic anhydride represented by the following general formula (I): (Wherein, R is an alkyl group, alkenyl group, aralkyl group, or aralkyl group having 5 or more carbon atoms, and n is 2 to 3
Represents an integer. (B) a water-soluble polymer obtained by polymerizing or copolymerizing a vinyl monomer in the presence of an alkyl mercaptan having 6 to 22 carbon atoms; A sizing composition for papermaking, comprising 1 to 100 parts by weight of a polymer. 2. The method according to claim 1, wherein the alkyl mercaptan having 6 to 22 carbon atoms is used in an amount of 0.01 to 10 based on the vinyl monomer.
The papermaking sizing composition according to claim 1, wherein the composition is used in an amount of mol%. 3. The vinyl monomer of (b) is acrylamide, acrylamide and a cationic vinyl monomer, or acrylamide and an anionic vinyl monomer.
2. The sizing composition for papermaking according to claim 1, wherein the composition is acrylamide, a cationic vinyl monomer and an anionic vinyl monomer. 4. A sizing method comprising using the papermaking sizing composition according to any one of claims 1 to 3.