JPS58104299A - Amphoteric paper strength enhancer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a paper strength enhancer, specifically, a paper strength enhancer using a water-soluble polymer obtained by quaternizing an amphoteric polymer mainly composed of acrylamide (mannilla modified product) as an active ingredient. Regarding drugs.

Conventionally, it has been known to use an amphoteric copolymer obtained by reacting an acryl-trido-acrylic acid copolymer as a paper strength enhancer, but this polymer generally has a poor paper strength effect. , especially when the papermaking system is neutral or alkaline, has almost no effect. Furthermore, an amphoteric copolymer obtained by copolymerizing acrylamide, acrylic acid, and methacrylic acid sialic aminoethyl ester or its salt has been proposed as a paper strength enhancer that can be used in a wide pH range. However, amino groups introduced via ester bonds are easily eliminated from the polymer by hydrolysis reactions, and therefore, K-ampholytic copolymers are still suitable for paper making, especially when the papermaking system is neutral or alkaline. It is difficult to provide the desired and consistent paper strength. Furthermore, as a paper strength agent, an amphoteric polymer obtained by reacting polyacrylamide with hypochlorous acid sorter in an alkaline region
It is also known as the Hofmann decomposition reaction, in which a carbo+syl group is introduced by hydrolysis of acrylamide along with the introduction of a primary amino group, but when this reaction is stored as an aqueous solution, the generated amino groups are Because it is unstable, most of it disappears within a few days at room temperature, halving the paper strength effect.

The present inventor has discovered that it can be used in a wide pH range regardless of the presence or absence of a fixing agent such as sulfuric acid, and that it can always stably exhibit an excellent paper strength enhancement effect in this pH range, and that We have conducted extensive research with the aim of obtaining a paper strength enhancer that can provide superior compressive strength, bursting strength, internal strength, tensile strength, etc. that are not found in strength enhancers. As a result, a quaternized product of an amphoteric polymer obtained by reacting a water-soluble copolymer of acrylamide and an α,β-unsaturated monocarboxylic acid is a normal mannilla-modified amphoteric polymer (mannilla-modified product).
We have discovered that the cationicity is significantly improved without the disadvantage of decreased cationicity in the neutral to alkaline range, and that it can be used as a brown paper strength enhancer that meets the above objectives. The present invention was finally completed.

That is, the present invention provides α) α,β-unsaturated heptadcarboxylic acid or) its salts (hereinafter referred to as α component) 1 to 15 mol 1G
, A) Acrylamide (hereinafter referred to as component) 55-99
'eti and C) other noniosic t-mers (hereinafter referred to as component C) that can be copolymerized with the above α) and h) 0 to 3011L
Formaldehyde and a secondary amine are reacted with a water-soluble copolymer consisting of t and t. ~40Yff,
An amphoteric paper strength enhancer containing as an active ingredient a polymer obtained by introducing an aminomethyl group of ruti and further reacting with a quaternizing agent to introduce at least a quaternary a,:/l nium group of ItL-. Pertains to.

The paper strength enhancing agent of the present invention exhibits an excellent paper strength enhancing effect that does not substantially change in a wide range of pH ranges from acidic to alkaline, for example, pH 4 to 9, especially when no sulfuric acid is used, Even when the amount used is small, it has the characteristic of imparting good paper strength, ie, compressive strength, bursting strength, internal strength, tensile strength, etc., to paper. In addition, the paper strength enhancer of the present invention also promotes the sizing effect of soap-type or emulsion-type Ojishi-based sizing agents, Arshi Luke Teshi Timer sizing agents, etc., which are commonly used in paper manufacturing, and the sizing effect of 2-Go sizing agents. It has the ability to reduce

The water-soluble copolymer which is the base of the active ingredient of the paper strength enhancer of the present invention can be obtained by copolymerizing a predetermined amount of the above C component to C component. Specific examples of the C component used include acrylic acid, methacrylic acid, etc., and alkali salts thereof such as alkali metal salts and ammonium salts obtained using caustic sorter, caustic potash, etc.
Component C is a component that can be incorporated into the copolymer of the present invention as required, and specifically includes vinyl esters such as vinyl acetate, piosic acid, etc.
Vinyl aromatic hydrocarbons such as styrene, α-methylstyrene, vinyltoluene, α,β-unsaturated t-nocarboxylic acid nitriles such as acrylonitrile and methacrylonitrile, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate,
In addition to C1-8 alkyl esters of acrylic acid or methacrylic acid such as 2-ethylhexyl acrylate, methacrylamide, lysidyl methacrylate, N-methyl 0-lylacrylamide, diacetone acrylamide, etc. An example of this is a nonionic columnar pick.

The blending ratio of the above C component to C component is Kg acid component in the obtained copolymer -15v:lti Good 1 L<ti2~1
2'eL-1b component 55-99r: L% preferably 60
-98 tjll, and C component 0-30 t. When the α component is less than 17%, the resulting modified copolymer becomes close to a cationic polymer, and when it exceeds 157%, the resulting copolymer is modified and used as a paper strength agent. However, it becomes difficult to impart excellent paper strength to paper, which is still undesirable. Furthermore, the above component C, which is used as necessary, is used in an amount of 30'tL or less on the premise that the modified copolymer obtained is water-soluble. The amount of hydrogen and alkyl esters of acrylic acid or methacrylic acid is preferably in the range of up to 20 tons.

The copolymerization reaction of the α component to C component can be carried out by various conventionally known methods. For example, preferably hydrogen peroxide,
A water-soluble radical generating catalyst such as potassium persulfate, □an'f::, t, etc. is added to the comonomer mixture in an amount of about 0.0%.
05 to 5% by weight, the concentration of 7mer is set to about 5 to 50% by weight in an aqueous medium, and the mixture is stirred for about 1 to 10 hours at a temperature of about 50 to 95°C. At this time, various water-soluble chemicals such as buffering agents such as sodium bicarbonate, primary or dibasic sodium phosphate, reducing agents such as dimethylamine and sodium thiosulfate, and chain transfer agents such as isozypyl alcohol and allyl alcohol are used. It is possible to use scales as appropriate in the same manner as in the present conventional method.

The polymer used as the active ingredient of the paper strength enhancer of the present invention can be obtained by reacting the water-soluble copolymer base obtained above with formaldide and a secondary amine, and then reacting with a quaternizing agent. It will be done. The reaction of the above base with formaldehyde and secondary amine is called Mannirashi reaction, and is carried out by a normal method, for example, by adding formaldehyde and secondary amine to an aqueous solution of the base resin,
It takes about 0.5 to 5 hours at 0°C. Here, formaldehyde may be an aqueous solution thereof (formali:,/) or formaldehyde.

Further, as secondary amines, dimethylamine, dimethylamine, methylethylamine, dimethylamine, methylethanolamic acid, jetanolamine, t-sulfoline,
Piverizhi and the like can be mentioned. There is no particular restriction on the order of addition of these, and either one may be added first or they may be added at the same time. may be reacted with the base resin.

Theoretically, the ratio of formaldehyde and secondary amine to be used may be equimolar, but it is preferable to use secondary amine in excess of 1,000 to formaldehyde (for example, 1.05 to 1.2 times the mole). is preferred. The amount of formaldehyde used is based on the base resin and the constituent parts! The range is such that ~40%, preferably 2 to 3% of aminomethyl groups (mannilla bases) are introduced.

The quaternization reaction that follows the above-mentioned mannilla reaction is carried out using the known 4
Approximately 0.0.
The reaction takes 5 to 10 hours to convert the aminomethyl group introduced by the Simannich reaction into a quaternary ammonium group.

The amount of the quaternizing agent used in the quaternization reaction can be determined as appropriate, but it should be an amount that will introduce at least IE groups, preferably about 2 to 30 mol, of quaternary ammonium groups into the resulting polymer. It is better. It is not necessary to convert all the ammonium groups into quaternary ammonium groups by this reaction, and it is preferable that some aminomethyl groups (tertiary amino groups) remain in the resulting polymer.

The quaternizing agents used in the above are ordinary ones,
For example, ethyl bromide, butyl bromide, benzyl bromide, methyl chloride, ethyl chloride, benzyl chloride, methyl iodide and other alkyl halides or aral halides; dimethyl sulfate, diethyl sulfate, dimethyl sulfite. , inorganic esters such as dimethyl ricinate; alcoholic esters such as dimethyl silicate, epipropylene hydroxide;

In this way, a polymer to be used as an active ingredient in the paper strength enhancer of the present invention can be obtained. The polymer has a cationic group, ie, a quaternary am7nium group, or a tertiary amino group in combination with the anionic group derived from the above-mentioned component α) by a mannilla reaction and a quaternization reaction. The cationic group is 1 to 40r in the polymer.
-Lu is introduced, and unless this is more or less than 1'F:ruti, the polymer becomes close to an anionic polymer. Conversely, if the cationic group exceeds 40EL'4, there is no particular advantage, and if the pH of the papermaking system is low and the amount of paper strength agent used is large, it tends to be difficult to fix the paper strength agent. Among the above cationic groups, it is necessary to introduce at least 1 mole of the quaternary atom group, otherwise the resulting polymer will be a normal mannilla and will change from a modified polymer. It has the disadvantage that it is not smooth and the effect of imparting paper strength is insufficient.

In this way, a polymer to be used as an active ingredient of the amphoteric paper strength enhancer of the present invention can be obtained. Among these polymers, the viscosity of an aqueous solution with a concentration of 10% by weight at pH 4 is 100-1000.
0006p! (25° C.) is preferred, and those having a viscosity of 500 to 200,000 cPs are most suitable as paper strength enhancers. The above-mentioned viscosity affects the properties as a paper strength enhancer, and as the viscosity decreases, the paper strength increasing effect gradually decreases, and as the viscosity increases, the structure of the paper tends to deteriorate.

When using the paper strength enhancer of the present invention, conventionally known methods may be followed. That is, the paper strength enhancer of the present invention is added to an aqueous dispersion of pulp in an amount of 0.05 to 3 weight based on the drying duty of the pulp, and papermaking is carried out with or without using sulfate bacide. The type of pulp is not particularly limited, and includes taracito pulp,
Any of sulfide pulp, semi-chemical pulp, kraft pulp, and disintegrated waste paper can be used, and these are usually used in the form of an aqueous dispersion of 1 to 5% by weight. Before papermaking, sizing agents are added in the same manner as in the past, such as reinforced zero gin soap, reinforced zero disier emulsion, alkyu Luketeshi timer emulsion, wax emulsion, alkenyl succinic acid soap, alkenyl succinic anhydride emul;
It is also possible to add fillers such as clay, talc, titanium oxide, calcium carbonate, etc. The amount of these additives to be used may be determined as appropriate depending on the type of the additive and the purpose of the paper, but it is usually 0.05 to 3% by weight of the sizing agent and/or the dry weight of the pulp. 5
~50 wt. of filler can be used. 'Paper in the present invention broadly includes both ordinary Western paper and paperboard.

Examples of production and use (Examples) of the paper strength enhancer of the present invention are given below.

Production Example 1 397 tons of soft water and 94.9 f of acrylamide were added to a Yotsurokolben equipped with a stirrer, a thermometer, and a nitrogen inlet tube.

9. Charge 5.1 tons of acrylic acid and 2.9 tons of 4896 caustic sorter, and heat to 40° C. while stirring while passing nitrogen gas. Then, 0.18 F of am7nium persulfate and 40.08 tons of anhydrous sodium bisulfite were added, and the polymerization reaction immediately started, and the internal temperature reached 90°C.

After keeping the temperature for 3 hours, it was diluted with 500 tons of deionized water to form an aqueous polymer solution with a non-volatile content of 10 cm (viscosity 60,000 PI).
) was obtained.

To this, 1.3f of caustic sorter, 12.6f of 50-dimethylamici aqueous solution and U37'lA forma v, 7x, +t were added, reacted at 45°C for 1 hour, and then cooled to 10°C.
Dimethyl sulfate 17.7F was added and the reaction was further carried out for 2 hours to quaternize the tertiary amine with 10C, and then diluted with deionized water to give a nonvolatile content IQs, pH 5, and viscosity 2000 c.
An aqueous polymer solution of ps was obtained.

This is referred to as paper strength enhancer A.

Production Examples 2 to 6 In the same manner as in Production Example 1 above, the amounts of each component were changed so that the α component to C component, the mannilla modification rate, and the quaternization rate of tertiary amine were as shown in Table 1. An aqueous polymer solution (paper strength enhancer B-F) having the physical properties shown in Table 2 was obtained. In addition, the results of paper strength enhancer A obtained in Production Example 1 are also listed in each table.

Comparative Examples 1 to 5 Consisting of the compositions shown in Table 1 in the same manner as in Production Example 1 above,
An aqueous polymer solution (comparative paper strength enhancer α to -) having the physical properties shown in Table 2 was obtained.

Table 1 The abbreviations in each component 4 in Table 1 indicate the following: O AA... Acrylic acid a- Acrylamide MAA... Methacrylic acid AN - Acrylic acid Nitrile No. 2 Table Example 1 of Pal "5cL-UKP, 500yd C3F).
A paper strength enhancer was added to the 5% aqueous dispersion.
(on a dry weight basis, the same applies hereinafter), and then add sulfuric acid at 1.0% and 3.0% (based on the pulp), respectively, or without adding it, using a Tatsupi Standart sheet machine. Basis weight 160±3f, /
The paper was made to look like W'. The pH during paper making was 7.5 without the addition of sulfate, 6.1 with the addition of 1.0%, and 4.5 with the addition of 3.0%.

Next, the wet paper was compressed and dehydrated at 7 Ktr/cd for 5 minutes, and then contact-dried for 3 minutes in a rotary dryer (surface temperature 120°C). The resulting paper stock was conditioned for 24 hours at 20° C. and 65 SRH.

The specific bursting strength of these paper stocks is JIS P811.
2) and specific compressive strength (JIS P 8126) were measured. The results are shown in Table 3 below for each paper strength enhancer used.

Table 3 also shows the results when no paper strength enhancer and sulfate were added (blank).

Table 3 Example 2 Palzu (L-BKP, 500t/C5F) 1.
5. To the aqueous dispersion, 10% calcium carbonate to the pulp,
Next, 0.5% paper strength enhancer was added to the pulp, and the basis weight was adjusted to 50±1 using a Tatsupi Stacytard sheet machine.
The paper was made so that the paper had a pH of 8.
It was 5.

Next, the wet paper was compressed and dehydrated at 7 edges/- for 5 minutes, and then contact-dried for 1 minute in a rotary dryer (surface temperature 110°C).

The resulting paper stock was conditioned for 24 hours at 20° C. and 65° RH.

The internal strength, tear length, and ash content of these paper stocks were measured according to the following methods.

Internal strength: Tappt RC308 (In
internal bond tatter) Breaking length: J
IS P 8113 Ash content: Electric furnace at 500°C for 3 hours The results obtained using a paper strength enhancer and the results obtained without the addition of a paper strength enhancer (': 5 rank) are shown in Table 4 below.

Table 4 Example 3 Palzu (L-BKP, 500d C5F) 1.5
To the aqueous dispersion, clay of 10% to pulp and paper strength enhancer to 0.5% of pulp were added, and then sulfuric acid was added to tS.
Add or do not add so that the thickness is 2%, and use Tatsupi Stantat Sheet Machishishi to make the basis weight 50±
The paper was made to have IP/m'.

The pH during paper making was 7.2 without the addition of sulfuric acid, 5.8 with the addition of 1 ts of sulfuric acid, and 5.0 with the addition of sulfuric acid 296.

Thereafter, each paper strength agent was evaluated in the same manner as in Example 2. The results are shown in Table 5 below.

Table 5

Claims (1)

[Scope of Claims] ■ α) α, β-Unsaturated t-nocarboxylic acid and/or its salts 1-15'e-1, h) Acrylamide 55-99v-1 and C) The above α), h) A water-soluble copolymer having a constituent unit of other nonionic copolymerizable nonionic t-mer-O to 30r- is reacted with formaldehyde and secondary amici to introduce an aminomethyl group of 1 to 40t, An amphoteric paper strength enhancer comprising, as an active ingredient, a polymer obtained by further reacting with a quaternizing agent to introduce at least a le syl-quaternary am7nium group.