JPH0765279B2 - Sizing composition for papermaking - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sizing composition for papermaking. More specifically, using a specific polyether compound as a dispersant,
The present invention relates to a neutral papermaking sizing agent in which a ketene dimer is stably dispersed.

[Conventional technology]

Conventionally, rosin or reinforced rosin (maleinated rosin) has been widely used as a sizing agent for papermaking, but this rosin-based sizing agent has many problems because it requires fixing with aluminum sulfate. That is, the fixing of the rosin-based sizing agent (acidic papermaking) with aluminum sulfate is
Since the pH of papermaking water is low (acidic), damage to the papermaking machine is large and the wastewater treatment load is heavy. Further, it has been pointed out that defects such as discoloration due to long-term storage of paper and poor printability are caused.

Further, when calcium carbonate is used as a filler, it cannot be used in an acidic papermaking system because calcium carbonate decomposes in an acidic solution. Calcium carbonate is one of the few domestically produced resources, it is inexpensive and has a high whiteness, so it is known to be effective when used as a filler for paper, but its use is extremely limited for the above reasons. Is the current situation. Therefore, overcoming the above drawbacks, without degrading the paper quality,
It has been desired to develop a neutral sizing agent that can use calcium carbonate.

In recent years, various neutral papermaking sizing agents have been proposed in order to achieve this object, and typical examples thereof include ketene dimers, alkenyl succinic anhydrides, isocyanate aziridine derivatives, succinimide derivatives, and rosins. Examples include anhydrides, other compounds having a carbonyl group, fatty acid anhydrides, etc. Among them, a sizing agent in which a ketene dimer is dispersed in water in a colloidal form is considered to be most promising, and numerous patents have been filed. Has been done.

As a dispersant (protective colloid agent) for ketene dimer,
It is known that nonionic, cationic, and anionic surfactants and polymer compounds are used.

The nonionic surfactant or dispersant has 8 to 8 carbon atoms.
Polyethylene oxide adducts of 18 higher alcohols or fatty acids, polyethylene oxide adducts of alkylphenols such as octylphenol and nonylphenol (Oil Chemistry, Volume 10, No. 5, p. 282), and polypropylenes of these higher alcohols, fatty acids, alkylphenols Block or random adducts of oxides and polyethylene oxides (Japanese Patent Laid-Open No. 50-53608, Japanese Patent Publication No. 55-37639), non-ionic polymers such as polyvinyl alcohol and oxidized starch (Japanese Patent Laid-Open No. 55-132799). Gazette) and the like.

Examples of cationic dispersants include cationic starch and epihalohydrin-modified polyalkylene polyamides (JP-A-48-48702), polyethyleneimine, polyvinylpyridine, cationic polyurethane resins and the like (JP-A-55).
-132799), a cationic vinyl copolymer (Japanese Patent Laid-Open No.
60-99097, JP-A-60-104599, JP-A-60
-219245, JP-A-60-220137) and the like.

Examples of the anionic dispersant include sodium naphthalene sulfonate formaldehyde condensate and sodium lignin sulfonate (JP-A-55-116898).

In fact, many cationic dispersants are used, and among them, cationic starch is the most.

[Problems to be solved by the invention]

The ketene dimer sizing agents currently on the market have a cationic surface potential (approx. Ζ-potential), and use a high cationic charge density polymer (+1 meq / g <) as a paper-strengthening agent and fixing agent. In the system, the sufficient sizing effect is not expressed, and therefore the amount of the sizing agent is unavoidably increased. In addition, the ketene dimer sizing agent dispersed with conventional nonionic and anionic surfactants and dispersants causes problems such as clogging of the pump during pumping and deposits of dust in the piping. Was not suitable for.

[Means for solving problems]

In view of the above situation, the inventors of the present invention develop a size performance with a low addition amount even when used with a paper-strengthening agent having a high cationic charge density (+1 meq / g <) or a fixing agent, and are mechanically stable. As a result of diligent studies to find a papermaking sizing composition effective as a ketene dimer sizing agent having sufficient properties, a ketene dimer is dispersed using a specific nonionic polyether compound as a dispersant. It was found that a sizing agent composition exhibiting sizing performance and excellent mechanical stability can be obtained with a low addition amount, and thus completed the present invention.

That is, the present invention is a polyether compound obtained by adding an alkylene oxide essentially containing ethylene oxide to a polyalkylene polyamine or polyethylene imine, wherein the total weight of the polyoxyethylene chain portion is 35 to 99 wt% of the total molecular weight. , And the average molecular weight is 300 to 10
It is intended to provide a sizing composition for papermaking, which comprises a polyether compound having a content of 0.00000 and a ketene dimer.

The polyether compound of the present invention is preferably an adduct of ethylene oxide alone or a block-shaped or partially block-shaped adduct of ethylene oxide and an alkylene oxide other than ethylene oxide. Propylene oxide is preferable as the alkylene oxide other than ethylene oxide, and the ratio of ethylene oxide / propylene oxide is
100/0 to 30/70 (wt%) is preferable.

Although the function of the present invention is not clear yet, it is presumed as follows. That is, the sizing effect is closely related to the charge density of the papermaking chemicals (here, the paper strength agent and the fixing agent), and particularly when the paper strength agent and the fixing agent having a high cationic charge density are added before the sizing agent. In, it is considered that adsorption is inhibited by the cationic sizing agent, and the effect is difficult to be expressed, but since the sizing agent of the present invention is nonionic,
Adsorption will not be hindered and the excellent size effect will be exhibited.

The ketene dimer according to the present invention is disclosed in JP-A-48-4870.
2, JP-A-52-110906, JP-A-52-118010
Any of the known ketene dimers disclosed in JP-A No. 55-98997, JP-A No. 55-116898 and the like can be used.

The ketene dimer is represented by the following general formula.

In the above formula, R and R'each have 8 to 24 carbon atoms, preferably 12 carbon atoms.
~ 22 hydrocarbon groups. Examples of these hydrocarbon groups include octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, alkyl groups such as eicosyl groups, octenyl, decenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl, eicosenyl groups, and other alkenyl groups, octaphenyl, Examples thereof include alkaryl groups such as nonylphenyl and dodecylphenyl groups, and among these, an alkyl group is particularly preferable. The ketene dimer may be used alone or in combination of two or more.

The polyether compound according to the present invention is obtained by adding alkylene oxide containing ethylene oxide to polyalkylene polyamine or polyethylene imine. Examples of the polyalkylene polyamine include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and the like,
Polyethylene polyamine is preferred. Examples of polyethyleneimine include those having a molecular weight of 200 to 70,000.

In the polyether compound according to the present invention, the total weight of the polyoxyethylene chain portion is 35 to 99% by weight, preferably 40 to 90% by weight, based on the total molecular weight. If it is less than 35% by weight of the total molecular weight, it becomes difficult to stably disperse the ketene dimer for a long period, and if it exceeds 99% by weight of the total molecular weight, the thermal stability of the polyether compound is deteriorated, which is not preferable.

The polyether compound can be easily obtained by adding an alkylene oxide to a polyamine compound by a usual method. Among them, a block or partial block adduct of ethylene oxide and propylene oxide is particularly preferable, and the order of addition may be any first.
The weight ratio of ethylene oxide and propylene oxide is preferably ethylene oxide / propylene oxide = 100/0 to 30/70, more preferably 100/0 to 50/50. When the ethylene oxide content is less than 30% by weight, the long-term dispersion stability of the papermaking size composition cannot be maintained, which is not preferable.

The molecular weight of the polyether compound is 300 to 100,000, preferably 400 to 60,000. When the molecular weight is less than 300, it becomes difficult to disperse the ketene dimer, and when the molecular weight exceeds 100,000, the thermal stability of the polyether compound is deteriorated, which is not preferable.

In order to obtain the papermaking sizing composition of the present invention, first, the above polyether compound is contained in an amount of 1 to 30% by weight, preferably 2 to 10%.
Dissolve in wt% water and raise the temperature. The ketene dimer dissolved in the heated aqueous solution is mixed and dispersed in an amount of 5 to 35% by weight, preferably 10 to 30% by weight. 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 has no size effect. Further, addition of other dispersants or emulsifiers may be carried out within a range that does not impair the storage stability effect, long-term dispersion stability effect and size performance of the sizing composition of the present invention.

The particle size of the ketene dimer dispersed in the present invention and the sizing composition dispersion is generally desired to be 5 microns or less. For example, the sizing composition according to the present invention is used in a state of being dispersed in water, and the particle size of the sizing particles dispersed in water is 5
It is desirable that the size is less than or equal to micron, preferably less than or equal to 1 micron. 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 size particles.

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-epihalohydrin-based polymer, polyethyleneimine, polyvinylpyridine and quaternary products thereof, polydimethylaminoethyl methacrylate and quaternary products thereof. , Polydiethylaminoethyl methacrylate and its quaternary products, and copolymers of these cationic monomers with 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 0.03 to 1% by weight, based on the weight of pulp as a solid content. It goes without saying that the addition level of these sizing agents is adjusted according to the sizing degree required for the target paper.

〔The invention's effect〕

The sizing composition for papermaking according to the present invention exhibits a sizing performance with a low addition amount even when used with a paper-strengthening agent having a high cationic charge density (+1 meq / g <), or a fixing agent, and exhibits mechanical stability. Is also excellent.

〔Example〕

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

[Preparation of sizing agent]

Examples 1-10 3 parts by weight of each polyether compound obtained by adding alkylene oxide to various starting materials shown in Table 1 was dissolved in water, and after heating, 17 parts by weight of stearyl ketene dimer was added thereto. In addition, water at 70 ° C. was further added to prepare a total of 100 parts by weight. Press this with a high pressure discharge type homogenizer
It was emulsified at 200 kg / cm ² and further cooled to obtain a size composition.

Comparative Examples 1 to 3 A sizing agent was prepared in the same manner as in the above Examples except that cationized starch (Comparative Examples 1 and 2) and a nonionic surfactant (Comparative Example 3) were used instead of the polyether compound of Examples. A composition was obtained.

The average particle size of the obtained sizing composition was all about 1 μm.
It was m. Table 1 shows the ζ-potential of the size particles.

[Comparison of Size Performance] Papermaking Conditions Papermaking used in this test was manufactured under the following conditions.

(Papermaking method) Pulp: NUKP (Canadian Standard Freeness 400
ml) Sizing agent: 0.03% (solid content based on pulp weight) Paper strength agent: 0.1% (solid content based on pulp weight) Cationic polyamide polymer (commercially available product, cationic colloid equivalent value +2.76 meq / g) Drainage improver: 0.03% (solid content relative to pulp weight) Cationic polyacrylamide polymer (commercially available product) Fixing pH: 6.5 Order of addition: pulp-paper strength enhancer-size- drainage improver-pH Adjustment (Ban sulphate soil) Papermaking: Tappy square handmade machine Press: 3.5kgw / cm ² × 2 minutes Drying: Rotary drum dryer, 100 ° C × 2 minutes Weighing: 100g / m ² Size performance test Size performance test The following method was used.

Size performance test: Complies with the Stick-Hit method (JIS P-8122).

Bend the four sides of the test paper upwards to form a boat shape, 2% NH ₄ SCN
Float on the aqueous solution. 1% Fe from above as soon as it floats
A drop of Cl ₃ aqueous solution was dropped on a test paper, and the time (seconds) until both the aqueous solutions permeated the paper and contacted and three red spots of iron thiocyanate appeared were measured.

Table 2 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 humidity control (20 ° C., 60% RH).

The sizing degree immediately after the papermaking shows the quality of the rising of the size effect, and the higher the value, the better.

[Comparison of Mechanical Stability] The mechanical stability was compared by the following test method.

Marlon test: Based on measurement of coagulant generation amount (JIS K-6387).

50 parts by weight of the sizing composition was accurately sampled, placed in a stainless steel sample container, and attached to a test device. And pressure
10 kg / cm ² for 5 minutes, the aggregates generated by treatment with rpm 1028r.pm filtered through a 200 mesh wire, after turning off sufficient water, were weighed aggregates and vacuum dried. In addition,
The mechanical stability is represented by the solidification rate based on the total solid content in the sample. This is calculated by the following formula.

C _R : Coagulation rate (wt%) W _c : Mass of dry coagulation (part by weight) W: Mass of sample (part by weight) TSC: Solid content (wt%) Table 3 shows the coagulation rate of each sizing composition. Shown in. The smaller the solidification rate, the better the mechanical stability.

Claims (4)

[Claims] 1. A polyether compound obtained by adding an alkylene oxide essentially containing ethylene oxide to a polyalkylene polyamine or polyethylene imine,
The total weight of the part of the polyoxyethylene chain is
35-99% by weight, with an average molecular weight of 300-100,000
And a ketene dimer. 2. A papermaking sizing composition according to claim 1, wherein the polyether compound is an adduct of ethylene oxide or a block-shaped or partially block-shaped adduct of ethylene oxide and an alkylene oxide other than ethylene oxide. object. 3. A polyether compound is ethylene oxide /
The sizing composition for papermaking according to claim 1 or 2, which is an adduct of propylene oxide = 100/0 to 30/70 (% by weight). 4. The papermaking sizing composition according to claim 1, 2 or 3, wherein the polyalkylene polyamine is polyethylene polyamine.