JPH05195485A - Additive for paper making and its production - Google Patents

Abstract

PURPOSE:To obtain the subject additive having low viscosity, excellent increasing effect on paper burst index and good operability by copolymerization of a (meth)acrylamide, ionic vinyl monomer and vinyl monomer bearing chain- transferring groups on its side chain followed by graft polymerization of a (meth)acrylamide, etc., thereto. CONSTITUTION:(A) (i) (Meth)acrylamide, preferably of 70 to 90mol% (based on the total moles of the monomer components constituting the major chain A), (ii) preferably 5 to 20mol% at least one of ionic vinyl monomers, and (iii) preferably 0.1 to 10mol% at least one of vinyl monomer bearing chain- transferring substituent on its side chain are copolymerized to form the major chain A. (B) Then, component (i) in (A) in an amount of 70 to 96mol% (based on the total moles of the monomers constituting the side chain B) and component (ii), preferably 4 to 30mol% are grafted to the major chain A, preferably to give the objective additive. The molar ratio of the constituent monomer for major chain A to that for the side chain B is preferably 1/5 to 5/1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a papermaking additive and a method for producing the same. For details, of the graft structure (meta)
The present invention relates to a papermaking additive containing an acrylamide copolymer and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, papermaking additives, especially paper strength enhancers, have been regarded as important in the production of paper and paperboard. The reasons for this are that the use of good quality pulp was restricted due to the deterioration of the situation of supply of raw wood, and the need to reuse used paper was further strengthened for the purpose of energy saving and resource saving. However, papermaking additives as paperboard modifiers have become even more indispensable.

On the other hand, for the purpose of improving the productivity with the speeding up of paper machines, or improving the quality according to the diversification of paper, the dependence on the drainage improver and the paper strength enhancer and the range of use thereof are further increased. It is widespread. Under these circumstances, polyacrylamide-based additives have become the mainstream as additives for papermaking.

Polyacrylamide-based papermaking additives are anionic type and cation (including amphoteric) depending on ionicity.
It can be classified into types. For example, as the anion type, a copolymer of acrylamide and an anionic vinyl monomer, α, β-unsaturated monocarboxylic acid or α, β-unsaturated dicarboxylic acid, or partial hydrolysis of an acrylamide copolymer Things are known. On the other hand, as the cation (amphoteric) type, there are a modified type and a copolymerized type based on the difference in the method of introducing the ionic functional group. For example, modified types include Hoffmann rearranged products of Mannich, mannich modified products, and the like, while copolymerized types include cationic vinyl monomers and (meth) acrylamides, and if necessary anionic vinyl monomers. Alternatively, various copolymers prepared by copolymerizing other non-polymerizable vinyl monomers are known (JP-A-60-94697).

However, in recent years, the use conditions of the papermaking additives have become more and more severe, so that in the conventionally known relatively low molecular weight polyacrylamide-based papermaking additives,
It has reached the limit in terms of its effect as an additive. for that reason,
A means of increasing the molecular weight is adopted to improve performance,
If the polymer is simply made to have a high molecular weight, the resulting copolymer has an excessively high viscosity, which results in poor dispersibility during papermaking. As a result, when such a copolymer is used as a papermaking additive, excessive cohesion occurs, and the texture of the papermaking is apt to be disturbed.

In order to solve this problem, attempts have been made to give a branched structure by using a cross-linking agent to increase the molecular weight of the resulting copolymer while suppressing the increase in viscosity thereof. The effect as a papermaking additive was not yet sufficient because the reactivity of the crosslinking agent was insufficient or it was difficult to introduce a uniform branched structure.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a papermaking additive containing a high-molecular weight (meth) acrylamide copolymer, having a relatively low viscosity, and excellent in fixability to pulp. The purpose is to provide.

[0008]

As a result of intensive studies to solve the above-mentioned problems of the prior art, the inventors of the present invention have found that a (meth) acrylamide copolymer having a graft structure has a high molecular weight (meta). ) Not only can an acrylamide copolymer be obtained without increasing the viscosity, but the copolymer is excellent in various effects as a papermaking additive, and further, the main chain and side chains of the graft structure can be obtained. It has been found that particularly when the ionic components are biased, the effect of increasing the paper strength is excellent, and the present invention has been completed.

That is, the present invention provides a graft copolymer containing (a) acrylamide and / or methacrylamide, and (b) at least one ionic vinyl monomer selected from anionic vinyl monomers and cationic vinyl monomers as a main component. A papermaking additive containing a coalescence, and further (1) (a) acrylamide and / or
Alternatively, methacrylamide, (b) at least one ionic vinyl monomer selected from anionic vinyl monomers and cationic vinyl monomers, and (c) at least one vinyl monomer having a chain transfer substituent in the side chain as a main component. After copolymerizing the main chain (A), the main chain (A) is graft-polymerized with the component (a) and the side chain (B) containing (b) as a main component. Method for producing additive for papermaking, (2) (a) acrylamide and / or methacrylamide, (b) at least one ionic vinyl monomer selected from anionic vinyl monomer and cationic vinyl monomer, and (c) chain transfer After copolymerizing the main chain (A) containing at least one vinyl monomer having a functional substituent as a main component, the main chain (A) (3) (a) Acrylamide and / or methacrylamide, and (c), wherein the side chain (B) containing the component (a) as a main component is graft-polymerized. After copolymerizing the main chain (A) containing at least one kind of vinyl monomer having a chain transfer substituent as a main component, the main chain (A) has the above-mentioned component (a), and (b) an anionic vinyl monomer and Side chain (B) containing at least one ionic vinyl monomer selected from cationic vinyl monomers as a main component
And a method for producing the papermaking additive.

In the present invention, the component (a), acrylamide or methacrylamide, can be used alone or in combination, but from the economical aspect, it is preferable to use acrylamide alone.

Among the ionic vinyl monomers as the component (b), examples of the anionic vinyl monomer (b-1) include monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; maleic acid, fumaric acid, Dicarboxylic acids such as itaconic acid, muconic acid and citraconic acid; organic sulfonic acids such as vinyl sulfonic acid, styrene sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid; or sodium salts and potassium salts of these various organic acids. can give. Examples of the cationic vinyl monomer (b-2) include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate,
Vinyl monomers having a tertiary amino group such as dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, allylamine, diallylamine, and triallylamine, or their salts of inorganic or organic acids such as hydrochloric acid, sulfuric acid, and acetic acid. Or a vinyl monomer containing a quaternary ammonium salt obtained by the reaction of the tertiary amino group-containing vinyl monomer with a quaternizing agent such as methyl chloride, benzyl chloride, dimethylsulfate and epichlorohydrin. These ionic vinyl monomers may be used alone or in combination of two or more.

As the vinyl monomer having a chain transfer substituent as the component (c), any vinyl monomer having a chain transfer functional group can be used without particular limitation. For example, allyl group, polyalkylene glycol group, N-substituted group. Examples thereof include vinyl monomers having an amide group and the like. Examples of the vinyl monomer having an allyl group include allyl (meth) acrylate, N-allyl (meth) acrylamide, and N, N-diallyl (meth) acrylamide. Also,
Any polyalkylene glycol group may be used as long as it has at least two oxyalkylene repeating units, and usually up to about 10 repeating units can be used. Specific examples include polyethylene glycol mono (meth) acrylates such as diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, and tetraethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylates similar to the above, Methoxy polyethylene glycol mono (meth) acrylate, polytrimethylene glycol mono (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, polyethylene glycol propylene glycol mono (meth) acrylate and the like can be mentioned. Further, as the vinyl monomer having an N-substituted amide group or the like, dimethylacrylamide, diacetoneacrylamide, isopropylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanecarboxylic acid and carbons thereof Examples thereof include alkyl esters of 1 to 4 and the like.

The additive for papermaking containing the (meth) acrylamide copolymer having a graft structure of the present invention is produced, for example, by the following graft polymerization method.

(1) After copolymerizing the main chain (A) containing the components (a), (b), and (c) as main components,
A method in which the main chain (A) is graft-polymerized with a side chain (B) containing the component (a) and the component (b) as main components.

(2) After copolymerizing the main chain (A) containing the components (a), (b), and (c) as main components,
A method of graft-polymerizing a side chain (B) containing the component (a) as a main component on the main chain (A).

(3) After copolymerizing the main chain (A) containing the components (a) and (c) as main components, the main chain (A) is charged with the components (a) and (b). Side chain as main component (B)
A method of graft polymerizing.

First, the amounts of various components used in the graft polymerization method (1) will be described. The component (a) used for the polymerization of the main chain (A) is usually about 60 to 98 mol%, preferably 70 to 96 mol%, based on the total molar sum of the monomer components constituting the main chain (A). Similarly, the component b) is usually about 1 to 40 mol%, preferably 5 to 20 mol%,
Similarly, the components (c) and (c) are usually 0.01 to 20 mol%, preferably 0.1 to 10 mol%. On the other hand, the component (a) used for the polymerization of the side chain (B) is usually about 60 to 99 mol%, preferably the component (a) with respect to the total molar sum of the monomer components constituting the side chain (B). 70 to 96 mol%, and the component (b) is also usually about 1 to 40 mol%, preferably 4 to 30 mol%.

In particular, the above-mentioned (b) ionic vinyl monomer is (b-1) anionic vinyl monomer and (b-2)
Use molar ratio of cationic vinyl monomer (b-1) /
(B-2) has a main chain (A) of 2 or more, preferably 4 or more, and a side chain (B) of 0.5 or less, preferably 0.3.
Or less in the main chain (A)
Or less, preferably 0.3 or less, and 2 or more in the side chain (B),
By imparting a bias to the ionicity so that it is preferably 4 or more, the paper strength increasing effect can be further improved.

The amounts of the various components used in the graft polymerization method of (2) are also the same as those of the component (a) used for the polymerization of the main chain (A) of the monomer components constituting the main chain (A). It is usually about 60 to 98 mol%, preferably 7 based on the total molar sum.
0 to 96 mol%, the component (b) is also usually about 1 to 40 mol%, preferably 5 to 20 mol%, and the component (c) is also usually about 0.01 to 20 mol%, preferably 0. 0.1 to 10 mol%. On the other hand, the side chain (B) contains the component (a) as a main component and is usually about 70 to 100 mol%, preferably 80 to 100 mol%.

The amounts of the various components used in the graft polymerization method of (3) are also the same as those of the component (a) used for the polymerization of the main chain (A) of the monomer components constituting the main chain (A). It is usually about 60 to 99.99 mol%, preferably about 70 to 99.9 mol%, and the component (c) is also usually about 0.01 to 40 mol%, preferably about 0.1 to 10 mol% based on the total molar sum. Three
It is set to 0 mol%. On the other hand, the component (a) used for the polymerization of the side chain (B) is usually about 60 to 99 mol%, preferably 70 to 96 mol% with respect to the total molar sum of the monomer components constituting the side chain (B). , And (b) components are also usually 1 to
It is about 40 mol%, preferably 4 to 30 mol%.

The papermaking additive of the present invention may further contain (d) a nonionic vinyl monomer or (e) a crosslinkable vinyl monomer in addition to the above-mentioned main component.
In the polymerization of the main chain (A), the amount of these optional components used is usually about 20 mol% or less, preferably 15 mol% or less of the component (d) based on the total molar sum of the monomer components constituting the main chain (A). Similarly, the mol% or less and the component (e) can be used usually in an amount of about 1 mol% or less, preferably 0.5 mol or less. Further, in the polymerization of the side chain (B), with respect to the total molar sum of the monomer components constituting the side chain (B),
The component (c) is usually about 5 mol% or less, preferably about 2 mol% or less, and the component (d) is similarly about 20 mol% or less,
It is preferably 15 mol% or less, and the component (e) is usually 1
It can be used in an amount of about mol% or less, preferably 0.5 mol or less. Further, in the polymerization of the side chain (B) of (2) or the linear chain (A) of (3), the component (b) is usually used in an amount of less than 5 mol%, preferably 2 mol% or less. You can

Examples of the nonionic vinyl monomer (d) include alkyl esters of the anionic vinyl monomer (B), acrylonitrile, styrene, vinyl acetate and methyl vinyl ether.

Typical examples of the (e) crosslinkable vinyl monomer include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth).
Di (meth) acrylates such as acrylates, bis (meth) acrylamides such as methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, hexamethylenebis (meth) acrylamide, divinyl adipate, divinyl sebacate, etc. Kind,
Allyl methacrylate, epoxy acrylates, urethane acrylates, N-methylol acrylamide,
Bifunctional vinyl monomers such as diallylamine, diallyldimethylammonium, diallylphthalate, diallylchlorendate and divinylbenzene, 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanurate, triallylamine, triallyltriallyl 3 such as melitate and N, N-diallyl acrylamide
Functional monomer, tetramethylolmethane tetraacrylate, tetraallylpyromellitate, N, N, N ',
Examples thereof include tetrafunctional vinyl monomers such as N′-tetraallyl-1,4-diaminobutane, tetraallylamine salt, and tetraallyloxyethane. Among these,
Since it is easy to control the reaction at the time of production, it is preferable to use a vinyl type double bond for all the functional groups.

In the graft polymerization method (2), the molar ratio of the component (b) of the main chain (A) and the component (b) of the side chain (B), that is, (A)-(b) :( B)-(b)
To be 1: 0 to 0.8, preferably 1: 0 to 0.5, and (A) in the graft polymerization method of (3).
-(B) :( B)-(b) is set to 0 to 0.8: 1, preferably 0 to 0.5: 1, and ions of the main chain (A) and the side chain (B). By imparting a bias to the properties, the paper strength increasing effect can be further improved.

In any of the above graft polymerization methods, the molar ratio (A) / (B) of the vinyl monomer constituting the main chain (A) and the side chain (B) is 1/5 to 5/1. Range, preferably 1/3 to 3/1, and the constituent monomers may be adjusted so that the amount used is within the range. If the molar ratio used is less than 1/5, the side chains cannot be sufficiently graft-polymerized, and if it is greater than 5/1, the proportion of side chains is small. Is insufficient to improve the paper strength increasing effect.

The production of such a graft copolymer can be carried out by various conventionally known methods, but in order to make the resulting copolymer sufficiently exhibit its performance as an additive for papermaking, the main chain (A) is required. It is preferable to select a formulation in which chain transfer is suppressed as much as possible during the polymerization of 1, and the graft efficiency is increased as much as possible during the polymerization of the side chain (B). For example, first, a predetermined reaction container is charged with the vinyl monomer constituting the main chain (A) and water, and a persulfate-based initiator such as potassium persulfate or ammonium persulfate, or these persulfates and sodium bisulfite are added. A desired water-soluble acrylamide-based copolymer by adding a redox-based polymerization initiator in the form of a combination with a reducing agent, or an ordinary radical polymerization initiator such as an azo-based initiator, and heating under stirring. To manufacture. Subsequently, the vinyl monomer constituting the side chain (B) is dropped into the system containing the water-soluble acrylamide copolymer, which is the main chain (A), to carry out graft polymerization to obtain a desired graft copolymer. Obtainable. The polymerization temperature is usually about 70 to 100 ° C., and preferably the polymerization temperature of the side chain (B) is higher than the polymerization temperature of the main chain (A) within the above range.

The molecular weight of the graft copolymer thus obtained is usually about 500,000 to 10,000,000. Especially 150
It is preferably 10,000 or more.

Further, the papermaking additive of the present invention containing the above graft copolymer can be used with a relatively low viscosity similar to the conventionally known cross-linking type (meth) acrylamide copolymer. When used as a paper strengthening agent, usually
15,000c at a solid content concentration of about 5 to 20% by weight
When used as a filler retention agent at about ps or less, 15,000 cp at a solid content concentration of about 1 to 10% by weight.
It is preferable to use it with properties of about s or less.

[0029]

Industrial Applicability The papermaking additive of the present invention containing a (meth) acrylamide copolymer having a graft structure has a high ionicity at the contact point between pulp fibers and has a paper-strengthening effect. It exhibits various characteristic performances as an additive for use. In particular, when the ionicity of the main chain and the graft chain is biased, the paper strength enhancing effect can be further improved. As a result, it exhibits various excellent effects as a papermaking additive even under recent severe papermaking conditions. In addition, it has a relatively low viscosity despite its high molecular weight copolymer and is excellent in workability.

[0030]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples. All parts and% are based on weight.

Example 1 A six-necked flask equipped with a stirrer, a thermometer, a reflux condenser, two dropping funnels and a nitrogen gas inlet tube was charged with 16 parts of acrylamide, 3.5 parts of 80% acrylic acid aqueous solution, and dimethyl. Aminoethyl methacrylate 1.5 parts, PE-350
(Nippon Oil and Fats Co., Ltd., polyethylene glycol methacrylate) 21.2 parts and ion-exchanged water 350 parts were charged, and oxygen in the reaction system was removed through nitrogen gas. Next, the inside of the system was heated to 40 ° C., and 0.25 part of ammonium persulfate and 0.15 part of sodium hydrogen sulfite were added as a polymerization initiator with stirring. After the temperature was raised to 85 ° C., the temperature was kept for 2 hours to obtain a copolymer serving as a main chain. After completion of the heat retention, 43 parts of acrylamide, 0.9 parts of 80% acrylic acid aqueous solution, and dimethylaminoethyl methacrylate were added to the copolymer.
6 parts and 310 parts of ion-exchanged water, 0.5 parts of potassium persulfate and 15 parts of ion-exchanged water were simultaneously added dropwise from separate dropping funnels over 1 hour, and after keeping the temperature for 1 hour,
Cool, pH 4.5, solids 15.6%, viscosity (25
A graft copolymer aqueous solution having a temperature of 8400 cps was obtained. Table 2 shows the property values of the resulting branched copolymer aqueous solution.

Examples 2 to 12 Examples 1 to 12 were the same as Example 1 except that at least one of the types of components (a) to (e) or the amount thereof was changed as shown in Table 1. The same operation was performed to obtain an aqueous graft copolymer solution. Table 2 shows the property values of the obtained copolymer aqueous solutions.

Comparative Example 1 Example 1 was repeated except that a copolymer was prepared by using the components (a) to (c) shown in Table 1 and the monomer was not added dropwise to cause reaction. The same operation was performed. Table 2 shows the property values of the obtained copolymer aqueous solution.

Comparative Example 2 In Example 1, the components (a) and (b) shown in Table 1 were used.
The same operation as in Example 1 was carried out except that PE-350 was used without using the components. Table 2 shows the property values of the obtained copolymer aqueous solution.

Comparative Example 3 The same operation as in Comparative Example 2 was carried out except that the components (a), (b) and (e) shown in Table 1 were used in Comparative Example 2. Table 2 shows the property values of the obtained copolymer aqueous solution.

Comparative Examples 4 to 6 The same operation as in Comparative Example 1 was carried out except that the components (a), (b), (d) and (e) shown in Table 1 were used in Comparative Example 1. went. Table 2 shows the property values of the obtained copolymer aqueous solution.

[0037]

[Table 1]

[0038]

[Table 2]

(Performance Evaluation Method 1) Waste corrugated paper was beaten with a Niagara type beater, and a pulp adjusted to 420 ml Canadian Standard Freeness (C.S.F.) with a sulfuric acid band was added to pulp 1.6%. Add pH 5.
5. Then, each copolymer aqueous solution obtained in each of the above Examples and Comparative Examples was added with 0.6% of pulp as a paper strengthening agent, and after stirring, the pulp slurry concentration became 0.1%. And diluted with a tapping sheet machine to obtain a basis weight of 1
Paper was made to have a weight of 50 g / m ^2, and press dehydration was performed at 5 Kg / cm ² for 2 minutes. Then, it was dried in a rotary dryer at 105 ° C. for 3 minutes and then dried at 20 ° C. and 65% R.A. H. 2 under the condition
After conditioned for 4 hours, the specific burst strength was measured according to JIS P 8112. The results are shown in Table 3.

(Performance Evaluation Method 2) BKP was beaten with a Niagara type beater, and pulp (pH 6.8) adjusted to (CSF) 550 ml was obtained in each of the above Examples and Comparative Examples. Add an aqueous copolymer solution as above,
The same operation as above was performed to measure the specific burst strength. The results are shown in Table 3.

[0041]

[Table 3]

From the results shown in Tables 2 and 3, the (meth) acrylamide-based copolymer obtained by the present invention is a high molecular weight polymer as compared with the conventional product, but has almost the same viscosity and excellent paper. It is recognized that the strength-enhancing effect is exhibited.

Claims (6)

[Claims] 1. A graft copolymer containing (a) acrylamide and / or methacrylamide, and (b) at least one ionic vinyl monomer selected from anionic vinyl monomers and cationic vinyl monomers as a main component. An additive for papermaking. 2. A side chain containing at least one ionic vinyl monomer selected from (a) acrylamide and / or methacrylamide, (b) an anionic vinyl monomer and a cationic vinyl monomer, and (c) a chain transfer substituent. After copolymerizing the main chain (A) containing at least one of the vinyl monomers described in 1. as the main component, the main chain (A) has the component (a) and the side chain (B) containing (b) as the main component. 2.) The method for producing an additive for papermaking according to claim 1, characterized in that 3. The ionic vinyl monomer (b-
1) Use molar ratio of anionic vinyl monomer and (b-2) cationic vinyl monomer (b-1) / (b-2)
The main chain (A) is 2 or more, the side chain (B) is 0.5 or less, or the main chain (A) is 0.5 or less, and the side chain (B) is 2 or more. Additives for papermaking. 4. A vinyl having (a) acrylamide and / or methacrylamide, at least one ionic vinyl monomer selected from (b) anionic vinyl monomer and cationic vinyl monomer, and (c) a chain transfer substituent. Copolymerizing a main chain (A) containing at least one kind of monomer as a main component, and then graft-polymerizing a side chain (B) containing the above-mentioned component (a) as a main component onto the main chain (A). The method for producing the papermaking additive according to claim 1. 5. A main chain (A) containing at least one of (a) acrylamide and / or methacrylamide, and (c) a vinyl monomer having a chain transfer substituent as a main component, and then the main chain is copolymerized. The above (a) component and (b) a side chain (B) containing at least one ionic vinyl monomer selected from anionic vinyl monomer and cationic vinyl monomer as a main component are graft-polymerized to (A). The method for producing an additive for papermaking according to claim 1. 6. The molar ratio of the vinyl monomer constituting the main chain (A) and the vinyl monomer constituting the side chain (B) used is (A) / (B) = 1/5 to 5/1. Items 1-5
The papermaking additive described.