JPH02139494A - Additive for paper making - Google Patents

Abstract

PURPOSE:To obtain an additive for paper making, containing a copolymer prepared by polymerizing specific components, such as (meth)acrylamide, a water-soluble cationic monomer (salt), primary amine or hydroxyl group- containing monomer, in a specified proportion and improved in enhancing effects on paper strength. CONSTITUTION:An additive for paper making obtained by containing a polymer prepared by blending (A) acrylamide and/or methacrylamide with (B) a water-soluble cationic monomer and/or salts thereof, (C) an alpha,beta-unsaturated mono- and/or dicarboxylic acids and/or salts thereof, (D) a divinyl monomer and (E) a primary amine or hydroxyl group-containing monomer, stirring and heating the resultant blend in the presence of a radical polymerization initiator and a chain extender. The amounts of the components based on the total number of mol of the components (A), (B) and (C) are 0.01-0.2mol% component (D) and 0.1-5mol% component (E).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a polyacrylamide (hereinafter referred to as PAM) used as a papermaking additive.

(Prior Art) It has been known in the paper industry to use acrylamide polymers as paper strength enhancers. recent years,
As part of energy saving and environmental measures, the paper manufacturing process has become more closed, and as a result, the addition rate of sulfuric acid, which has traditionally been used, has naturally been restricted.

Therefore, it is desired to develop a drug that can produce sufficient paper strength even when a small amount of sulfuric acid is added, or even when no sulfuric acid is added. Examples of paper strength enhancers that can be used in the H region include (a) acrylamide and Φ) basic monomers such as dimethylaminoethyl methacrylate;
(c) Amphoteric water-soluble copolymers consisting of α, β unsaturated monocarboxylic acids or dicarboxylic acids have been proposed (for example, JP-A-54'-30913, JP-A-60-946).
97 etc.).

The paper strength enhancing effect of this type of polyacrylamide-based paper strength enhancer is mainly due to hydrogen bonding between the amide groups in the polymer and the hydroxyl groups of cellulose fibers, but the paper strength enhancer effectively exerts paper strength. Naturally, in order to do this, it must be adsorbed or fixed on the cellulose fibers or fine fibers that make up the paper. Therefore, in order to increase the adhesion rate to the cellulose fibers or fine fibers that make up paper, both cationic and anionic functional groups are introduced. Since this will reduce the amide moiety that is effective for developing paper strength, an optimal range will naturally be set for the amount of both of these functional groups introduced. There is a limit to the effectiveness of paper strength enhancers.

(Five Problems of the Invention) Therefore, an object of the present invention is to increase the paper strength enhancing effect of the above-mentioned amphoteric polyacrylamide copolymer.

(Means for Solving the Problems) The present invention provides (a) acrylamide and/or methacrylamide, (b) water-soluble cationic monomers and/or salts thereof, (c) α, β-unsaturated monomers and/or or (d) 0.01 to 0.2 mol% of a divinyl monomer, and (e) a monomer having a primary amine or hydroxyl group, based on the total molar sum of the polyacrylamide polymer constituent components consisting of dicarboxylic acid and/or its salts. The paper-making additive contains a copolymer obtained by polymerizing 0.0.1 to 5 mol%.

In the present invention, acrylamide or methacrylamide, which is the component (a), may be used alone or in combination, but acrylamide is preferred from an economic standpoint.

Typical examples of the water-soluble cationic monomer (b) component include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, or diethylaminepropyl (meth)acrylamide. Vinyl monomers having a tertiary amino group or their salts with inorganic or organic acids such as hydrochloric acid, sulfuric acid or acetic acid; Examples include salt containing a quaternary ammonium salt obtained by reaction with a grading agent.

Examples of the α,β-unsaturated mono- and/or dicarboxylic acid monomers include monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, or sodium thereof. salts, alkali metal salts such as potassium salts, ammonium salts, and the like.

Further, as the divinyl monomer (d), di(meth)acrylates such as ethylene glycol (meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, methylene bis(meth)acrylamide, ethylene bis(meth)acrylate, etc. (meth)acrylamide, hexamethylene bis(meth)
Examples include bis(meth)acrylamides such as acrylamide, divinyl esters such as divinyl adipate and divinyl sebacate, epoxy acrylates, urethane acrylates, and divinyl monomers.

Monomer (e) having the above primary amine or hydroxyl group
Typical examples include monoallylamine, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate.

When used alone, the above components (d) and (e) cannot form a copolymer sufficient to exhibit the desired paper strength enhancement effect, but when used in combination, the desired paper strength enhancement effect is increased. It is found that copolymers are obtained. The amount added is
The above component (d) is 0.01 to 0.2 mol% of the total molar sum of monomers (a), (b) and (c) used.
It is preferable to use the component (e) in an amount of 0.1 to 5 mol%. If the amount of the copolymer added is small, a sufficient paper strength enhancing effect cannot be obtained, and if the amount added is too large, the copolymer becomes water-insoluble, which is disadvantageous.
Regarding the three components (c), appropriate ranges are naturally set based on the above-mentioned performance as an amphoteric copolymer. That is, among the three components (a), (b), and (c), (a) component 19
8 to 60 mol%, rb) component is 1 to 20 mol%, (c)
The components need to be 1 to 20 mol%, preferably (a) component 96 to 70 mol%, and (b) component 2 to 15 mol%.
mol%, component (c) 2 to 15 mol%. Outside this range, a sufficient paper strength enhancement effect cannot be obtained.

Furthermore, if desired, in addition to the above-mentioned components and additives, it is also possible to introduce any additives that can be copolymerized with these components. Typical examples include esters of acrylic acid or methacrylic acid with anionic monomers such as vinyl sulfonic acid and styrene sulfonic acid or alcohols having 1 to 8 carbon atoms, methacrylamide, acrylonitrile, styrene, and vinyl acetate. , nonionic monomers such as methyl vinyl ether, and the like.

The copolymer used in the present invention can be synthesized by various conventionally known methods. For example, the above monomers and water are charged into a predetermined reaction vessel, and a normal redox polymerization initiator, such as a persulfate such as potassium persulfate or ammonium persulfate, or a combination of these and a reducing agent such as sodium bisulfite, is used. Add a radical polymerization initiator,
Further, if necessary, the desired copolymer can be obtained by appropriately using a chain transfer agent such as isopropyl alcohol or allyl alcohol and heating while stirring.

(Function) By using the amphoteric copolymer containing components (d) and (e) as monomer components of the present invention as an additive for paper manufacturing, the use of components (d) and (e) alone Although the reason for the superior effect obtained from partially cross-linked polymers is currently unclear,
When component (e) is used in combination with the crosslinking reaction of divinyl monomer, the crosslinking of component (e) occurs at a different position and time, resulting in changes in the structure of the polymer.
It is believed that it is effective in synthesizing high molecular weight polymers and exhibits excellent effects in terms of paper strength.

Furthermore, although the mechanism of the crosslinking effect of the el component is not entirely clear, it is presumed that it is due to the occurrence of hydrogen abstraction from the carbon atom that is connected to the primary amine or hydroxyl group.

The present invention will be explained below with reference to Examples.

(Examples 1 to 8 and Comparative Examples 1 to 7) Into a four-eye flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 158 g of 40% acrylamide [aqueous solution] and 80% acrylic acid aqueous solution were added. 3.6g, dimethylaminoethyl methacrylate 6.3g, methylenebisacrylamide 0.049g, monoallylamine 0.23
g and 255 g of ion-exchanged water were charged, the pH was adjusted to 4.1 with a 15% sulfuric acid aqueous solution, and oxygen in the reaction system was removed by passing nitrogen gas.

Then, while stirring, 0.38 g of ammonium persulfate and O.16 sodium bisulfite were added as polymerization initiators.
After adding 50 g, the temperature was raised to 85°C and kept at 85°C for 2 hours. After cooling, at pH 4.6 and concentration 15.6%,
An aqueous copolymer solution having a viscosity (25°C) of 9800 centivoids was obtained. This is referred to as paper strength enhancer A.

This is referred to as Example 1, and for the remaining Examples 2 to 8 and Comparative Examples 1 to 7, the monomer composition was changed, and the amount of 15% sulfuric acid aqueous solution and the star of the polymerization initiator were changed accordingly. The same operation as in Example 1 was performed to obtain an aqueous copolymer solution. These were designated as paper strength enhancers B to H and a to g.

In addition, in the examples, the (d) component and (e) component were used together, but in the comparative example, the above (d) component and (
e) None or only one of the components was used.

Table 1 (Test Example) Canadian Standard Freeness (c, S, F) obtained from recycled cardboard 420mj! sulfuric acid was added to the solution to give a concentration of 0% at pH 116.8 and 1.6χ at pH 5.5, and then each copolymer aqueous solution obtained in the above Examples and Comparative Examples was used as a paper strength agent to give a concentration of 0% to pulp. 6%
After adding and stirring, the pulp slurry concentration was reduced to 0.1%.
After making paper using a hand paper machine, it was pressed for 5 kg for 2 minutes, and then dried for 3 minutes at 105°C in a drum dryer for 24 hours at 2o'C and 65% RH. The specific bursting strength was measured in accordance with JIS P-8112.

The results are shown in Table 2 below.

AM: acrylamide, DM dimethylaminoethyl methacrylate AA niacrylic acid, ■A: itaconic acid, MA: maleic acid DMC: methacryloyloxyethyl trimethylammonium chloride MBAM: methylene bisacrylamide, MAAm: mo, noarylamine HEA: 2-hydroxy Molecular Weight of Ethyl Acrylate Table 2 The molecular weight of each prototype was determined using a Toyo Soda TSK-GEL PW column and a GPC method using an Eve column with respect to polyethylene oxide 1 standard material.

Patent applicant Harima Kasei Kogyo Co., Ltd. Agent: Patent Attorney Hisao Ishii

Claims (1)

[Claims] (a) acrylamide and/or methacrylamide, (b) water-soluble cationic monomers and/or their salts, (c) α,β-unsaturated mono- and/or dicarboxylic acids, and/or (d) 0.01 to 0.2 mol% of the divinyl monomer and (e) 0.1 to 5 mol% of the monomer having a primary amine or hydroxyl group, based on the total molar sum of the polyacrylamide polymer constituents consisting of the salts thereof. A papermaking additive characterized by containing a copolymer polymerized in combination with the following.