JPS6350597A - Paper strength enhancer - Google Patents

Abstract

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

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a paper strength agent comprising a polyacrylamide-based amphoteric water-soluble copolymer. In recent years, it has been known to use polymers as paper strength enhancers.
Is glue used in the paper manufacturing process as part of energy saving and environmental measures? With the progress of sulfuric acid, the addition rate of sulfuric acid, which has been conventionally used, has naturally become limited. Therefore, it is desired to develop a drug that can produce sufficient paper strength even when sulfuric acid bend is not added or is not added. For example, acrylamide, α,
Amphoteric, water-soluble copolymers of β-unsaturated monocarboxylic or dicarboxylic acids and dimethylaminoethyl methacrylate, such as basic heptamers, have been proposed (e.g.
JP-A-54-80918, JP-A-60-94697, etc.)
0 <Problem that the invention is trying to solve> However,
These conventional amphoteric copolymers still have insufficient paper strength enhancing effects, and it has been desired to develop a drug that has the effect of increasing the strength of the paper.

As a result of intensive studies in response to such demands, the present inventors found that a copolymer containing a bifunctional vinyl heptamer as a copolymer component in a (meth)acrylamide-based amphoteric copolymer has the following properties: The present invention was completed by the discovery of a superior paper strength-enhancing effect compared to copolymers that do not contain copolymers. meth)acrylamide (wherein R1 is hydrogen or a methyl group s R1e R1 is the same or different alkyl group having 1 to 4 carbon atoms, X is oxygen or -NH- group, and A is an alkylene group having 1 to 8 carbon atoms At least one (@) α, β-unsaturated mono- and/or cicatric acid, and/or its salts and (d) a difunctional vinyl monomer, the above (1)/
The scolding ratio of (b) / (e) is 60-98/20-1/
20 to 1, and (d) is (a), (b),
A paper strength agent is provided which comprises a copolymer in an amount of 0.01 to 0.6% by weight based on the total weight of the copolymer.

The (meth)acrylamide component (1) may be acrylamide or methacrylamide, each of which may be used alone or in combination @acrylamide is preferred industrially. The basic monomer (b) component is, for example, dimethic Aminoethi fi/(meth)acrylate, diethyl
Examples include chemical compounds having an 8th-class amino group such as aminoethyl/L/(meth)acrylate, diflv aminopropy/I/(meth)acrylamide, and diethylaminopropy/L/(meth)acrylamide. Examples of acid addition salts of Kabetsumar include salts obtained by adding inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, or organic acids such as formic acid, acetic acid, and globionic acid to the above-mentioned compounds having an 8th-class amino group. Examples of the basic monomers mentioned above include the basic monomers having an 8th-class amino group and agglomerated methyl, benzyl chloride, and dimethylene.
Mention may be made of chemical compounds containing quaternary ammonium salts obtained by reaction with quaternizing agents such as sulfuric acid, ethyl/L' sulfuric acid, or epichlorohydrin.

(e) To illustrate the above anionic senomer, acrylic
acids, monocarboxylic acids such as methacrylic acid, cicarboxylic acids such as maleic acid, tumalic acid, and itaconic acid, or alkali metal salts or ammonium salts thereof such as sodium salts and potassium salts (d) Difunctional Examples of vinyl hexamers include ethylene glycol di(meth)acrylate, diethylene glycol ~
di(methane acrylate, triethylene glycol di(
Di(meth)acrylates such as meth)acrylate, bis(meth)acrylamides such as methylenebis(meth)acrylamide, ethylenebis(meth)acrylamide, hexamethylenebis(meth)acrylamide, diviny adipate, diviny sebacate p Examples include divinylμ esters, epoxy acrylates, urethane acrylates, divinylbenzene, etc.

The present invention is characterized in that, in an amphoteric water-soluble copolymer useful as a paper strength agent, (d
A difunctional vinyl hexamer is essential. The paper strength enhancing effect brought about by an amphoteric copolymer containing a difunctional vinyl monomer as a copolymer component is superior to that of an amphoteric copolymer that does not copolymerize the difunctional vinyl monomer. Although the reason for this is currently unclear, it is believed that when difunctional vinyl monomers are copolymerized, the molecular structure of the resulting copolymer has a branched structure. It is presumed that this works favorably for cross-linking between the seven loin fibers after paper making, and as a result contributes to improving paper strength.

The amount of the difunctional vinylic acid added is 0.01 to 0.6% by weight, preferably 0.01 to 0.6% by weight, based on the total weight of the difunctional polymers (a), (b), and (c) used. .02~0
．． 8% by weight @ If the amount added is small, sufficient paper strength enhancement effect cannot be obtained, and if the amount added is too large, the copolymer becomes water-insoluble, which is disadvantageous for the cinema.Also, (a) above , (b
), (e) Appropriate ranges are naturally set for the eight components, ◇ that is, (a) and (b).

(@) Among the 8 components, component (A) is 98 to 60 mo/%/
%, component (b) is 1-20 mol%, component (e) is 1-2
It is necessary that 0 mo/L'*, preferably (a
) component 96 to 70 moA/*, (b) component 2 to 16
7% to 115%, ((1) component 2 to 15M/115M. Outside this range, a sufficient paper strength enhancement effect cannot be obtained.

In addition to the above-mentioned essential constituent monomers (a) * (b) -((13-(d)), the copolymer used in the button of the present invention also contains nonionic heptamer-1 which can be copolymerized with these For example, it is possible to introduce acrylonitrium μ, methi μ acrylate, hydroxyethyl fi/(meth)acrylate, styrene, or vinyl acetate to an extent that does not impair the paper strength enhancing effect and the water solubility of the copolymer. The copolymer used in the invention can be synthesized by various conventionally known methods.For example, in a predetermined reaction vessel,
Ordinary Fujika/L, such as redocnu-based polymerization initiators, prepared by preparing the above monomers and water, and combining them with a persulfate such as potassium persulfate or ammonium persulfate, or a reducing agent such as hydrogen sulfite or IJium. 'Add a polymerization initiator, and if necessary, use a chain transfer agent such as isopropyl alcohol or allyl alcohol, and stir while stirring.
The desired copolymer can be obtained without heating.◎A preferred copolymer has a viscosity of an aqueous solution of 15 to 15% by weight at a pH of 4.5 to 5.0.
,000 voices (25℃), special [80~8
A copolymer with 00 voids is preferable @The viscosity of the copolymer is
The viscosity range of 10 to 1000 voids is 10 to 1000 voids. Anything that deviates from this is not desirable.

When using the paper strength enhancer of the present invention, conventionally known methods may be followed. In other words, in the aqueous dispersion of Bade,
0.05 to 8% by weight of the paper strength enhancer of the present invention is added to the pulp drying chamber fkK, and paper is made in the presence or absence of sulfuric acid. Fillers such as clay, resin, titanium oxide, etc. can be added.

The present invention will be explained below with reference to Examples.◎Example 1-
10 and Comparative Examples 1 to 4 A 50*acrylamide aqueous solution 1 was placed in a Yotsuro flask equipped with a stirrer, a thermometer, a reflux condenser, and a gas inlet tube.
25F, 80% acrylic/L/acid water ga 5.4v% dimethylaminoethyl methacrylate 9.4r, methylene bisacrylamide 0.076F and ion exchange water 376
The pH was adjusted to 4.7 with a 2ON-sulfuric acid aqueous solution, and oxygen in the reaction system was removed by passing nitrogen gas.

Then, with stirring, 0.859 ammonium persulfate and 0.14 sodium bisulfite were added as initiators.
After adding t, the temperature was raised to 90°C i″t′ and kept at 90°C for 2 hours. After cooling, at pH 4.6 and concentration 15.8m,
An aqueous copolymer solution with a viscosity (25° C.) of 95.4 Bo and f was obtained. This is referred to as paper strength enhancer A.

The above is referred to as Example 1, and the remaining 54MA Examples 2 to 10 and Comparative Examples 1 and -4 were carried out except that the monomer composition was changed and the amount of 2ON-sulfuric acid aqueous solution and the amount of polymerization initiator were changed accordingly. The same operation as in Example 1 was carried out to obtain an aqueous copolymer solution.

The properties of the copolymer aqueous solutions obtained in each Example and Comparative Example are shown in Table 1 along with the composition of the copolymer.

Application Examples 1 to 10 and Comparative Application Examples 1 to 4 Canadian
Standard freeness 400rnj pulp (cardboard waste paper) 3-strength souffle with 0.5% sulfuric acid band
(on a pulp dry weight basis, the same applies hereafter), and then 0.8% each of the paper strength enhancers A-J and 1 to d were added and mixed. After stirring for 1 minute, reduce the concentration of Bulbswory to 1.
Diluted to 96% and made into paper using a Tappl standard hand paper machine,
After dehydration pressing, dry at 110℃ for 4 minutes,
A handmade paper of ±2 ri/ze was produced.

For each stock, the specific burst strength is determined according to JIS P-81121, and the compressive strength is determined according to JISP-8126K.
jjl was established. The results are shown in Table 2. As is clear from the table, the paper strength enhancer of the present invention has an excellent paper strength enhancement effect.Table 2

Claims (1)

[Claims] Constituent monomers are (a) (meth)acrylamide (b) Formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 is hydrogen or a methyl group, R_2, R_3
are the same or different alkyl groups having 1 to 4 carbon atoms, X is oxygen or an -NH- group, and A is an alkylene group having 1 to 3 carbon atoms. ) at least one selected from the basic monomers represented by (c) α,β-unsaturated mono- and/or dicarboxylic acids and/or salts thereof; and (d) Consisting of a difunctional vinyl monomer, the above (a)/
The molar ratio of (b)/(c) is 60-98/20-1/20
1 and in which (d) is 0.01 to 0.5% by weight based on the total weight of (a), (b), and (c).