JPH0723595B2 - Sizing composition for papermaking - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sizing composition for papermaking. More specifically, it relates to a novel papermaking sizing composition which can be used in the neutral or alkaline range of the pH of papermaking water and has stable dispersion of ketene dimer fine particles.

[Conventional technology]

Conventionally, rosin or reinforced rosin (maleated rosin) has been widely used as a sizing agent for papermaking. However, this rosin-based sizing agent has many problems because it requires fixing with aluminum sulfate. That is, fixing with aluminum sulfate is performed by using the papermaking water during papermaking.
It has been pointed out that the low pH (acidicity) greatly damages the papermaking opportunity, impairs the printability of the paper, and also causes the risk of discoloration due to long-term storage of the paper and the heavy load of wastewater treatment. or,
When calcium carbonate is used as a filler, rosin-based sizing agents cannot be used because calcium carbonate decomposes in an acidic solution. Calcium carbonate is cheaper than talc, and is also one of the most abundant resources in Japan. It is easily available and has high whiteness, so if used as a paper filler,
Although it is known to be effective, its use is extremely limited for the above reasons. Therefore, it has been desired to develop a neutral papermaking sizing agent that overcomes the above-mentioned drawbacks and can reduce wastewater treatment without deteriorating the paper quality and can use calcium carbonate.

In order to achieve this purpose in recent years, various neutral sizing agents have been proposed, but among them, sizing agents in which a ketene dimer is dispersed colloidally in water are considered to be the most promising.
Many patents have been filed.

[Problems to be solved by the invention]

However, despite these many research efforts,
The ketene dimer sizing agent has drawbacks that it takes time to develop the size effect and it is difficult to keep the ketene dimer fine particles as a stable dispersion liquid.

Generally, when a ketene dimer type sizing agent is used, the sizing performance immediately after papermaking is poor, and it is said that time is required to obtain sufficient sizing performance compared to the amount of the sizing agent used. This problem is generally pointed out as having a poor rise in the size effect, but it is easily conceivable that this poor rise will lead to the following drawbacks. That is, it is difficult to control the quality of a paper such as a writing paper or a milk carton which has a high size effect on the final product. Further, in order to obtain a high size effect, it has to be shipped in several days, but it goes without saying that the storage until the shipment results in high paper cost. On the other hand, in the case of coated paper, an internal sizing agent is used to control the amount of liquid absorbed in the coating process.

Currently, coating is often performed continuously from paper making,
In this case, if the size effect is not exhibited immediately after the wet paper is dried (immediately after papermaking), it is completely useless. Ketene dimer size can be used in the neutral range. Despite the excellent performances such as the effect of sizing with a small amount of addition and the obtaining of high-sized paper, the present situation is that the use thereof is extremely limited due to the above reasons.

In addition, it is of course necessary to give due consideration to the dispersion stability and storage stability of the sizing composition, especially the mechanical stability. The mechanical stability refers to stability against mechanical share from the outside during transportation of the sizing agent or use of the sizing agent, which is particularly important among dispersion stability. However, such dispersion stability is improved by lowering the concentration of active ingredient in the sizing composition. However, a product having a low concentration of active ingredients is expensive in terms of transportation, filling, etc., and requires a large-capacity container for storage, which is extremely uneconomical. Therefore, in the paper manufacturing industry, there is a demand for the development of a sizing agent having a high effective concentration, good dispersion stability, good rise of size performance, and excellent size performance effect.

[Means for solving problems]

In view of the above situation, the present inventors have a high concentration of the active ingredient, dispersion stability, storage stability good aqueous dispersion,
Particularly good rise of size performance, having excellent size performance effect, as a result of intensive research to find a ketene dimer size sizing composition for papermaking, by mixing a specific ester compound with a ketene dimer, The present invention has been completed by finding that a sizing composition having good dispersion stability, good rise of size performance, and excellent size performance effect can be obtained even in a region where the concentration of the active ingredient is high.

That is, the present invention has a compound represented by the following general formula (1) and a solubility parameter in the range of 8.0 to 11.0,
Monocyclic carboxylic acid component and saturated alcohol, consisting of an alcohol component selected from cyclic alcohols and unsaturated polyhydric alcohols, the ester compound having no hydrophilic group other than the ester bond 99.8 / 0.2 ~ 80 by weight ratio A sizing composition for papermaking which is dispersed in water at a ratio of / 20.

(In the formula, R ₁ and R ₂ are an alkyl group, an alkenyl group or an aryl group having 8 to 24 carbon atoms.) The ketene dimer constituting the present invention is disclosed in JP-A-48-48.
702, JP-A-52-110906, JP-A-52-11801
Any of the known ketene dimers disclosed in JP-A No. 0, JP-A-55-98997, JP-A-55-116898, JP-A-60-99097 and the like can be used.

In the ketene dimer represented by the general formula (1), R ₁ and R ₂ each represent a hydrocarbon group having 8 to 24 carbon atoms, preferably 12 to 22 carbon atoms. Examples of this hydrocarbon group include octyl,
Alkyl groups such as decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl groups, octenyl,
Examples thereof include alkenyl groups such as decenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl and eicosenyl groups, and aryl groups such as octylphenyl, nonylphenyl and dodecylphenyl groups. Of these, an alkyl group is most preferable, but the ketene dimer is not limited to one kind alone, and may be a mixture of two or more kinds.

In order to obtain the ketene dimer (1) according to the present invention, for example, a known method of reacting a raw material fatty acid mixture with phosphorus trichloride to obtain a fatty acid chloride, and then performing a dehydrochlorination reaction in the presence of a tertiary amine catalyst. Should be applied.

The ester compound which is another component constituting the present invention is required to have a solubility parameter in the range of 8.0 to 11.0 and to have no hydrophilic group other than the ester bond. Specific examples of the carboxylic acid forming the ester include monocyclic carboxylic acids (phenylacetic acid, benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc.). Further, as the other component alcohol constituting the ester, n-first saturated alcohol (methanol,
Ethanol, 1-propanol, 1-butanol, n-
Amyl alcohol, n-hexyl alcohol, n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-lauryl alcohol, n-cetyl alcohol, n-octadecyl alcohol, etc., iso-primary saturated alcohol (isobutyl alcohol, Isoamyl alcohol, 2-methyl-1-pentanol, 6-methyl-
1-heptanol, dihydrocitronellol, secondary and trisaturated alcohols (2-propanol, 2-butanol,
tert-butyl alcohol, 2-hexanol, 3-methyl-2-pentanol, 2-octanol, 3-octanol, 2-methyl-3-heptanol, 6-methyl-
4-heptanol, 2-undecanol, etc.), cyclic alcohol (furfuryl alcohol, cyclohexanol,
Benzyl alcohol, 2-phenyl-2-propanol, cinnamyl alcohol, 1-methyl-4-isopropenyl-2-cyclohexanol, etc.), unsaturated polyhydric alcohols (6-methyl-3-hepten-2-ol, nerol) , Geraniol, citronellol, etc.) and the like, and the ester size compound composed of these components can provide the sizing composition for papermaking of the present invention. Even if the solubility parameter is in the range of 8.0 to 11.0, the effect of the present invention cannot be obtained unless it is an ester compound.

Further, the mixing ratio of the ketene dimer represented by the general formula (1) and the ester compound having a solubility parameter within the range of 8.0 to 11.0 is also important, and when the ratio is higher than 99.8 / 0.2, the dispersion stability is significantly deteriorated. However, when the ratio becomes smaller than 80/20, the phenomenon that the rising becomes defective can be seen. That is, the blending ratio must be within the range of 99.8 / 0.2 to 80/20.

To obtain the sizing composition of the present invention, first, the ketene dimer is melted at a temperature equal to or higher than its melting point, and the ester compound of the present invention is dissolved therein. Next, while maintaining the molten state of this mixture, it is mixed and dispersed in water which has been heated in advance. The temperature at the time of dispersion is desirably 100 ° C or lower, preferably 80 ° C or lower. At too high a temperature, the ketene dimer can react with water to give a reaction product that does not have a size effect. In addition, an appropriate emulsifier or dispersant is required for this mixing and dispersion, and as this dispersant, known ketene dimer emulsifiers and dispersants can be used. That is, there are various nonionic, cationic and anionic surfactants and dispersants, and preferred examples thereof include the following compounds. Examples of nonionic surfactants and dispersants include polyethylene oxide adducts of higher alcohols or fatty acids having 8 to 18 carbon atoms and polyethylene oxide adducts of alkylphenols such as octylphenol and nonylphenol (Oil Chemistry, Volume 10, Vol. No. 5, p. 282), and block or random adducts of these higher alcohols, fatty acids, and alkylphenols with polypropylene oxide and polyethylene oxide (JP-A-50-53608, JP-B-55).
-37639), non-ionic polymers such as polyvinyl alcohol and oxidized starch (JP-A-55-132799), and the like. Examples of cationic dispersants include:
Epihalohydrin modified products of cationized starch and polyalkylene polyamide (JP-A-48-48702), polyethyleneimine, polyvinyl pyridine, cationic polyurethane resin, etc. (JP-A-55-132799), cationic vinyl copolymer (JP-A-60-99097, JP-A-60-104
599, JP 60-219245, JP 60-22013
No. 7, etc.) and the like. Further, as anionic dispersants, sodium naphthalene sulfonate formaldehyde condensate and sodium lignin sulfonate (JP-A-55)
-116898) and the like. Of these, cationic dispersants are most preferred. The amount of these emulsifiers and dispersants added is preferably 5 to 100% by weight, more preferably 1 to 100% by weight, based on the mixture of the ketene dimer and the ester compound.
It is 0 to 50% by weight. If the amount of the dispersant is less than this range, the stability of the sizing agent dispersion will be poor, and if too much is added, the sizing effect will be reduced, such being undesirable.

In order to use the sizing agent of the present invention with good yield, it is effective to use a fixing agent, and a cationic polymer is preferable as the fixing agent. Preferred examples of the cationic polymer used as the fixing agent include cationized starch, cationized cellulose, polyamide-based polymer, polyethyleneimine, polyvinyl pyridine and its quaternized product, polydimethylaminoethyl methacrylate and its quaternized product, poly Examples thereof include dimethylaminoethyl methacrylate and its quaternary products, and copolymers of these cationic monomers and acrylamide.

In carrying out the present invention, the sizing composition of the present invention is added in an amount of 0.01 to 2% by weight, preferably 0.05 to 1% by weight, based on the solid weight of the pulp. It goes without saying that the addition level of these sizing agents is adjusted according to the sizing degree required by the target paper.

As described above, the sizing composition according to the present invention is used in the form of being dispersed in water, and the particle size of the sizing particles dispersed in water is 5 μm or less, preferably 1 μm or less. Is desirable. If the particle size is larger than 5 microns, the stability of the dispersion liquid may be impaired or the size effect may be deteriorated. A homomixer, an ultrasonic emulsifier, a high-pressure discharge homogenizer, or the like can be used to disperse the sizing particles.

〔The invention's effect〕

The aqueous dispersion according to the present invention has good dispersion stability, good rise of size performance, and excellent size performance effect.

〔Example〕

The present invention will be described in detail below with reference to production examples and examples, but the present invention is not limited to these examples and the like.

The parts in the examples are based on weight.

(Preparation of sizing agent dispersion liquid) Various ketene dimers and ester compounds are melt-mixed at 70 to 80 ° C, hot water (70 to 80 ° C) containing various dispersants is added, and a pressure of 200 kg / is obtained with a high-pressure discharge homogenizer. emulsify in cm ² ,
Further cooling was performed to obtain a size composition. The composition of the obtained sizing composition and the dispersant used are shown in Tables 1 and 2.

(Papermaking conditions) The paper used in this test was manufactured under the following conditions.

Pulp: LBKP (Canadian Standard Freeness 400
ml) Amount of sizing agent: 0.1% solid content based on pulp weight Fixing agent: cationized starch (commercial product) Solid content 0.2 to 0.85% based on pulp weight Retention aid: Cationic polyacrylamide polymer (commercial product) ) Solid content 0.02% relative to pulp weight Filler: heavy calcium carbonate (commercial product) Add by adjusting calcium carbonate in the paper to 12% Fixing pH: 8.2 Order of addition: Pulp-filler-fixing agent- Sizing agent-Yield improver Papermaking: Tappy square hand machine Press: 3.5kg w / cm ² x 2 minutes Drying: Rotary dryer, 100 ° C x 40 seconds Weighing: 70g / m ² (size degree Test) The sizing test was performed by the following method.

Sizing test: Stickhit method (JIS P-8122) Bend the four sides of the test paper upward to make a boat shape, 2% NH ₄ SCN
Float on the aqueous solution. At the same time as floating
A drop of the FeCl ₃ aqueous solution was dropped on a test paper, and the time (seconds) until both of the aqueous solutions permeated the paper and contacted and three red spots of iron thiocyanate appeared were measured.

Table 3 shows the test results obtained by measuring the sizing degree of the paper made under the above conditions immediately after the paper making and after one day of temperature control (20 ° C. × 60%). The sizing degree immediately after the papermaking shows whether the sizing effect is raised or not, and the higher the value, the better.

(Stability Test of Sizing Composition) The dispersion stability test of the sizing composition was conducted after leaving the sizing composition shown in Table 1 at 5 ° C., 20 ° C. and 40 ° C. for 1 month each. The state of dispersion was observed with the naked eye. The mechanical stability of the sizing composition was performed by the Marlon test. The condition of the Marlon test was that the sizing agent was treated with 20 kgw for 10 minutes, filtered through a 200-mesh wire net, and the filtration residue was measured.

The evaluation of dispersion stability at 5 ° C., 20 ° C., and 40 ° C. is indicated by ◯, Δ, and x, and the meanings are as follows.

◯: The emulsified state is almost the same as that at the beginning.

Δ: The viscosity is slightly increased, but it can be used.

X: The emulsion is thickened or gelled and cannot be used. Or it cannot be used due to creaming.

The results of the Marlon test show the amount of agglomerates left on the 200 mesh gauze as a percentage by weight of effective solids. Therefore, the smaller the value, the better the mechanical stability. The results are shown in Table 3.

Continuation of front page (56) References JP-A-58-91894 (JP, A) JP-A-58-91895 (JP, A) JP-B-59-47760 (JP, B2)

Claims (1)

[Claims] 1. A general formula (1) (In the formula, R ₁ and R ₂ are an alkyl group, an alkenyl group or an aryl group having 8 to 24 carbon atoms.) And a solubility parameter in the range of 8.0 to 11.0 and a monocyclic ring. Formula carboxylic acid component and saturated alcohol, consisting of an alcohol component selected from cyclic alcohols and unsaturated polyhydric alcohols, an ester compound having no hydrophilic group other than the ester bond, the weight ratio 99.8 / 0.2 ~ 80 / A papermaking sizing composition comprising an aqueous dispersion containing 20 parts by weight.