JPH0647798B2 - Surface sizing agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface sizing agent.

[Conventional technology]

BACKGROUND ART Conventionally, surface sizing agents composed of a maleic acid-styrene-based polymer and an acrylic polymer have been the mainstream of surface sizing agents because they can be manufactured industrially at low cost.

[Problems to be solved by the invention]

However, they have a weak sizing effect, especially on neutral or alkaline papers.

[Means for solving problems]

The present inventors have arrived at the present invention as a result of earnest research to obtain a surface sizing agent having a strong sizing effect even in a neutral or alkaline papermaking base paper.

That is, the present invention is (a) the general formula (In the formula, R ₁ is hydrogen or a methyl group, and R ₂ is a hydrocarbon group having 4 or less carbon atoms.) A unit of a (meth) acrylic acid short chain ester represented by the formula (b). (In the formula, R ₃ is hydrogen or a methyl group, and R ₄ is a hydrocarbon group having 8 or more carbon atoms.) A unit of a (meth) acrylic acid long chain ester represented by the formula (c). Or (In the formula, R ₅ is hydrogen or a methyl group, and R ₆ has 1 to 2 carbon atoms.
4 hydrocarbon group or a hydrocarbon group containing an oxyalkylene group, A is an alkylene group having 2 to 4 carbon atoms, and n is 0 to 1
0, M ₁ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an amine cation. ), A unit of an unsaturated sulfonic acid (salt) monomer containing a (meth) allyl sulfosuccinate ester (salt), (d) a general formula (Wherein R ₇ is hydrogen or a methyl group, M ₂ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an amine cation), and an unsaturated carboxylic acid containing a (meth) acrylic acid (salt) ( (Salt) A surface sizing agent characterized by comprising a water-soluble or water-dispersible polymer comprising a monomer unit and optionally (e) another nonionic vinyl monomer unit.

In the general formula (1) of (a), the hydrocarbon group having 4 or less carbon atoms for R ₂ includes an alkyl group (such as methyl, ethyl, propyl, isopropyl, butyl group) and a cycloalkyl group (such as cyclopropyl group). And so on.

Of these, preferred is an alkyl group having 1 to 4 carbon atoms.

Specific examples of the (meth) acrylic acid short-chain ester represented by the general formula (1) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and a mixture of two or more thereof. To be

In the general formula (2) of (b), the alkyl, aralkyl or cycloalkyl group having 8 to 24 carbon atoms of R ₄ is an alkyl group (octyl, 2-ethylhexyl, decyl, undecyl, dodecyl, hexadecyl, octadecyl, eicosyl). Group), an aralkyl group (such as a butylphenyl group), and a cycloalkyl group (such as a butylcyclohexyl group).

Of these, preferred is an alkyl group having 8 to 24 carbon atoms.

Specific examples of the (meth) acrylic acid long chain ester represented by the general formula (2) include 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, and heptadecyl (meth). ) Acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) acrylate and the like, and mixtures of two or more thereof.

In the general formulas (3) and (4) of (c), the carbon number of R ₆ is 1 to
24 hydrocarbon groups include alkyl groups (methyl, ethyl, butyl, octyl, decyl, undecyl, dodecyl, hexadecyl, octadecyl, eicosyl groups, etc.), aralkyl groups (benzyl group, etc.), cycloalkyl groups (cyclohexyl group, etc.), etc. Can be given.

Of these, preferred is an alkyl group having 8 to 20 carbon atoms.

The hydrocarbon containing an oxyalkylene group is R'O
A group represented by A'm (wherein R'is a hydrocarbon, A'is an alkylene group having 2 to 4 carbon atoms, and m is an integer of 1 or more).

In the above, the hydrocarbon group of R'has 1 to 22 carbon atoms.
Alkyl groups (methyl, ethyl, butyl, octyl, decyl, undecyl, dodecyl, hexadecyl, octadecyl, eicosyl groups, etc.), (alkyl) aryl groups (butylphenyl, nonylphenyl groups, etc.), cycloalkyl groups (cyclohexyl group, etc.) can give.
Examples of the alkylene group having 2 to 4 carbon atoms of A'include ethylene group, propylene group, butylene group and the like. A '
Of these, an ethylene group is preferred. m is preferably 1
~ 4. n is preferably 0-4. When n is larger than 10, the polymerizability becomes poor.

As the alkali metal of M ₁ , sodium, potassium,
Examples of alkaline earth metals such as lithium include calcium, magnesium and aluminum, and examples of amine cations include alkanolamine (triethanolamine and the like) cations and alkylamine (dimethylamine and trimethylamine and the like) cations. M ₁
Of these, preferred are sodium, potassium and ammonium.

Examples of (meth) allyl sulfosuccinic acid ester (salt) represented by the general formula (3) or (4) include allyl lauryl sulfosuccinic acid or its sodium salt, allyl stearyl sulfosuccinic acid or its sodium salt, and nonylphenoxytetra. Examples thereof include oxyethylene-allyl sulfosuccinic acid or its ammonium salt, and mixtures of two or more thereof.

The (meth) allyl sulfosuccinic acid ester (salt) represented by the general formula (3) or (4) may optionally contain other unsaturated sulfonic acid (salt) monomer. Examples of the unsaturated sulfonic acid (salt) monomer include those disclosed in Japanese Patent Application No. 59-247529.

The amount of the (meth) allylsulfosuccinic acid ester (salt) unit is usually 10% or more, preferably 20% or more, particularly preferably 50%, based on the weight of the unit of all unsaturated sulfonic acid (salt) monomer. % Or more.

If the amount of the (meth) allyl sulfosuccinate (salt) unit is less than 10%, a satisfactory size effect cannot be obtained.

In the general formula (5) of (d), examples of M ₂ include the same as M ₁ in the general formulas (3) and (4). M ₂
Preferred among them are sodium, potassium and ammonium.

Specific examples of the (meth) acrylic acid (salt) represented by the general formula (5) include (meth) acrylic acid, its sodium salt, its ammonium salt, its potassium salt, and the like, and mixtures of two or more thereof. Can be given.

The (meth) acrylic acid (salt) represented by the general formula (5) may optionally contain another unsaturated carboxylic acid (salt) monomer. Examples of the unsaturated carboxylic acid (salt) monomer include those described in Japanese Patent Application No. 59-247529.

The amount of (meth) acrylic acid (salt) units is usually 10% based on the weight of all unsaturated carboxylic acid (salt) monomer units.
Or more, preferably 20% or more, particularly preferably 50% or more. The amount of units of (meth) acrylic acid (salt) is 10
If it is less than%, a satisfactory size effect cannot be obtained.

Examples of the nonionic vinyl monomer in the nonionic vinyl monomer unit (e) include the following monomers and mixtures of two or more thereof.

(e-1) Water-soluble nonionic vinyl monomer (e-1-1) Amide group-containing vinyl monomer (meth) acrylamide, N-alkyl (meth) acrylamide [N-methylacrylamide, N-hexylacrylamide Etc.], N, N-dialkyl (meth) acrylamide [N, N-dimethylacrylamide, N, N
-Di-n-propylacrylamide etc.], N-hydroxyalkyl (meth) acrylamide [N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide etc.], N, N-dihydroxyalkyl (meth) acrylamide [N, N-di-2-hydroxyethyl (meth) acrylamide, etc.], vinyl lactam (N-vinylpyrrolidone, etc.), etc. (e-1-2) hydroxyl group-containing vinyl monomer hydroxy lower alkyl (meth) acrylate [hydroxyethyl (meth ) Acrylate, hydroxypropyl (meth) acrylate, etc.], polyethylene glycol (meth) acrylate [triethylene glycol (meth) acrylate, etc.) (e-2) Oil-soluble nonionic vinyl monomer (e-2-1) Aromatic hydrocarbon vinyl monomer Styrene, α (E-2-2) unsaturated dicarboxylic acid ester such as alkyl styrene (α-methyl styrene), etc. Maleic acid diester having 1 to 12 (preferably 1 to 8) carbon atoms (diethyl maleate, dibutyl maleate, etc.), etc. e-2-3) Vinyl ester, vinyl acetate, etc. (e-2-4) Unsaturated nitrile, (meth) acrylonitrile, etc. Of these, preferred are amide group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, Aromatic hydrocarbon vinyl monomers, unsaturated dicarboxylic acid esters and unsaturated nitriles.

Constituting the water-soluble or water-dispersible polymer in the present invention
The amount of (a) is usually 1 to 80%, preferably 5 to 70%, particularly preferably 10 to 60%, based on the weight of the polymer. When the amount of (a) is less than 1%, a satisfactory size effect cannot be obtained, and when it exceeds 80%, the size effect tends to be deteriorated.

The amount of (b) is usually 1 to 70% based on the weight of the polymer,
It is preferably 5 to 60%, particularly preferably 10 to 50%. When the amount of (b) is less than 1%, a satisfactory size effect cannot be obtained, and when it exceeds 70%, the size effect tends to decrease.

The amount of (c) is usually 0.1 to 50, based on the weight of the polymer.
%, Preferably 1-40%, particularly preferably 1-30%
Is. When the amount of (c) is less than 0.1%, a satisfactory size effect cannot be obtained, and when it exceeds 50%, the size effect tends to decrease.

The amount of (d) is usually 1 to 70% based on the weight of the polymer,
It is preferably 5 to 60%, particularly preferably 10 to 50%. If the amount of (d) is less than 1%, a satisfactory size effect cannot be obtained, and if it exceeds 70%, the size effect tends to decrease.

The amount of (e) is usually 0 to 50%, based on the weight of the polymer,
It is preferably 0 to 40%, particularly preferably 0 to 30%. When (e) is water-soluble, the amount of (e) is usually 0-4.
0%, preferably 0 to 30%, particularly preferably 0 to 20
%, And when it is oil-soluble, it is usually 0 to 50%, preferably 0 to 40%, and particularly preferably 0 to 30%.

The [total of (a) and (b)] is usually 2 to 5 based on the weight of the polymer.
It is 98.9%, preferably 10-94%, particularly preferably 20-89%.

[The sum of (c) and (d)] is usually 1.
1 to 98%, preferably 6 to 90%, particularly preferably 1
1 to 80%.

Of [the sum of (c) and (d)], usually 1 to 100%, preferably 2 to 100%, particularly preferably 5 to 100% is in a salt form. If the salt form is less than 1%, it is difficult to obtain sufficient water solubility or water dispersibility of the polymer.

The water-soluble or water-dispersible polymer in the present invention can be produced by a usual solution polymerization method. Examples of the solvent for carrying out the solution polymerization include water; lower alcohols such as methyl alcohol and isopropyl alcohol; cellosolves such as methyl cellosolve and ethyl cellosolve; and mixed solvents of two or more thereof. As the polymerization initiator, peroxides (benzoyl peroxide, dicumyl peroxide, potassium persulfate, etc.), azo compounds (azobisisobutyronitrile, dimethyl-2,2′-)
Azobisisobutyrate, etc.), redox catalyst systems (ammonium persulfate and triethanolamine, potassium persulfate and sodium bisulfite, etc.) and the like.
Further, a polymerization regulator such as mercaptans (butyl mercaptan, dodecyl mercaptan, etc.) can be used. The polymerization temperature is usually from 20 ° C to the reflux temperature of the solvent.

It can also be produced by a conventional emulsion polymerization method, precipitation polymerization method, or the like.

The molecular weight of the water-soluble or water-dispersible polymer in the present invention is usually 2,000 to 2,000,000, preferably 5,
It is 000 to 1,000,000. Molecular weight 2,000
If it is less than 0, a sufficient size effect cannot be obtained, and
If it exceeds, 000,000, the viscosity of the aqueous solution or dispersion of the polymer becomes large and the workability is deteriorated.

Sulfonic acid groups (-SO in water-soluble or water-dispersible polymers)
The content of ₃ H) (calculated in the form of sulfonic acid when it is in the form of sulfonic acid salt) is usually 0.01 to 25%, preferably 0.1 to 20%, based on the weight of the polymer. , Particularly preferably 0.1 to 15%.

Carboxylic acid group (-CO in a water-soluble or water-dispersible polymer)
The content of OH) (calculated in the form of carboxylic acid when it is a salt of carboxylic acid) is usually 0.6 to 40%, preferably 3 to 35%, and particularly preferably, based on the weight of the polymer. Is 6 to 30%.

In the water-soluble or water-dispersible polymer [sulfonic acid group (-S
O ₃ H) and total content of carboxylic acid group (-COOH)]
(If it is an acid salt, calculate it in the acid form)
It is usually 1 to 55%, preferably 3 based on the weight of the polymer.
-50%, particularly preferably 6-45%.

The base paper which is surface-sized by the surface sizing agent of the present invention is not particularly limited, and is not limited by pulp, filler, internally added sizing agent, pH at the time of papermaking, paper strengthening agent, retention aid, and the like. For example, high-quality paper base paper and coated paper base paper made under acidic conditions; medium-quality paper base paper mixed with waste paper pulp and mechanical pulp; neutral or alkaline papermaking with internal size of alkyl ketene dimer or alkenyl succinic anhydride High quality paper base paper and coated paper base paper; base papers such as liners are included.

When using the surface sizing agent of the present invention, a sizing solution or coating color (hereinafter represented by a sizing solution) is prepared from other compounding agents, if necessary. As the above-mentioned compounding agent, a binder (raw starch (corn starch,
Tapioca starch, etc.), modified starch (oxidized starch, enzyme-modified starch, etc.), polyvinyl alcohol,
Polyacrylamide, vegetable gums, SBR latex,
Casein, etc.] Dyes, preservatives (preservatives such as starch)
And so on.

The concentration of the surface sizing agent of the present invention in the sizing liquid is determined by the amount of paper absorbed at the time of application, the amount of application to the paper and the size required for the paper, but usually 0.01 to 5 weight. %
Is.

Since the surface sizing agent of the present invention has a stronger size than the conventional surface sizing agent, the amount applied to paper is sufficient even at a low level and is usually 0.001 to ² g / m ² (solid content). ), Preferably 0.005 to 1 g / m ² (solid content),
It is particularly preferably 0.005 to 0.5 / m ² (solid content). If the coating amount is too large, a good pen writing size cannot be obtained and the object of the present invention cannot be achieved.

The sizing liquid containing the surface sizing agent of the present invention can be applied to the papermaking process by a usual method. That is, the size liquid is applied to the paper surface using a coating device such as a size press, a gate roll, a calender, an air knife, or a coater, or sprayed on the wet paper of the wet part, and then dried to perform surface sizing of the paper. be able to.

〔Example〕

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

Example 1 120 g of water and 180 g of isopropyl alcohol were charged into a 1,000 cc Kolben equipped with a stirring blade, a cooling tube, a dropping funnel, a nitrogen blowing tube and a thermometer, and the temperature was raised to the reflux temperature under stirring with a nitrogen stream.

50 g of isopropyl alcohol and 50 water in a dropping funnel
g, 60 g of methylmethacrylate, 60 g of hexadecylmethacrylate, 20 g of sodium allyllaurylsulfosuccinate, 60 g of methacrylic acid and 2 g of dimethyl-2,2'-azobisisobutyrate were added to Kolben in about 2 hours. Dropped. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours. After the aging reaction, it was partially neutralized with an aqueous solution containing 9 g of sodium hydroxide, and then isopropyl alcohol was distilled off to obtain 2 of a water-dispersible polymer.
A 5% by weight aqueous dispersion was used as the surface sizing agent of the present invention.

Example 2 The same Kolven as in Example 1 was charged with 150 g of water and 150 g of methyl alcohol, and the temperature was raised to the reflux temperature while stirring with a nitrogen stream.

A dropping funnel was charged with 50 g of methyl alcohol, 40 g of butyl methacrylate, 70 g of dodecyl methacrylate, 10 g of allyl stearyl sulfosuccinate, 80 g of methacrylic acid, and 2 g of dimethyl-2,2'-azobisisobutyrate, and about 2 hours. In short, it was dripped into Kolben. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours. After the aging reaction, methyl alcohol and water were distilled off to obtain 200 g of a polymer. A 20% by weight aqueous solution of a water-soluble polymer obtained by neutralizing this polymer with an aqueous solution containing 63 g of ammonia water (25%) was used as the surface sizing agent of the present invention.

Example 3 90 g of water, 210 g of isopropyl alcohol and 20 g of nonylphenoxytetraoxyethylene / ammonium allylsulfosuccinate were charged into the same Kolben as in Example 1, and the temperature was raised to the reflux temperature under stirring with a nitrogen stream.

To the dropping funnel, 40 g of butyl acrylate, 50 g of butyl methacrylate, 40 g of octadecyl methacrylate
g, and 50 g of methacrylic acid were charged, and it took about 2 hours to add dropwise to Kolben. 10 g of an aqueous solution containing 1 g of potassium persulfate was charged in a Kolben immediately before and just after the dropping. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours.
After completion of the aging, isopropyl alcohol and water were distilled off to obtain 200 g of a polymer. A 20% by weight aqueous solution of a water-soluble polymer obtained by neutralizing this polymer with an aqueous solution containing 23 g of sodium hydroxide was used as the surface sizing agent of the present invention.

Comparative Example 1 120 g of water and 180 g of isopropyl alcohol were charged in the same Kolben as in Example 1, and the mixture was stirred under a nitrogen stream.
The temperature was raised to the reflux temperature.

60 g of isopropyl alcohol and 40 water in a dropping funnel
g, butyl methacrylate 89 g, methacrylic acid 11
1 g and 2 g of dicumyl peroxide were charged to about 2
It took time to drop it into Kolben. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours. After the aging reaction, isopropyl alcohol and water were distilled off to obtain 200 g of a polymer. 2 of a water-soluble polymer obtained by neutralizing this polymer with an aqueous solution containing 88 g of ammonia water (25%)
A 0% by weight aqueous solution was used as a comparative surface sizing agent.

Comparative Example 2 A 20% by weight aqueous solution of a maleic acid-styrene polymer obtained by the method of Example 1 described in JP-B-53-25049 was used as a surface sizing agent for comparison.

Reference Example 1 150 g of water and 150 g of methyl alcohol were charged in the same Kolben as in Example 1, and the temperature was raised to the reflux temperature while stirring with a nitrogen stream.

A dropping funnel was charged with 50 g of methyl alcohol, 110 g of butyl methacrylate, 10 g of sodium allyl stearyl sulfosuccinate, 80 g of methacrylic acid and 2 g of dimethyl-2,2'-azobisisobutyrate, and dripped into Kolben in about 2 hours. did. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours. After the aging reaction, methyl alcohol and water were distilled off to obtain 200 g of a polymer. A 20 wt% aqueous solution of a water-soluble polymer obtained by neutralizing this polymer with an aqueous solution containing 63 g of ammonia water (25%) was used as a reference surface sizing agent.

Reference Example 2 150 g of water and 150 g of methyl alcohol were charged into the same Kolben as in Example 1, and the temperature was raised to the reflux temperature while stirring with a nitrogen stream.

A dropping funnel was charged with 50 g of methyl alcohol, 110 g of dodecyl methacrylate, 10 g of sodium allyl stearyl sulfosuccinate, 80 g of methacrylic acid and 2 g of dimethyl-2,2'-azobisisobutyrate,
It took about 2 hours to add dropwise to Kolben. After the dropping, an aging reaction was performed at a reflux temperature for about 2 hours. After the aging reaction, methyl alcohol and water were distilled off to obtain 200 g of a polymer.
A 20 wt% aqueous solution of a water-soluble polymer obtained by neutralizing this polymer with an aqueous solution containing 63 g of ammonia water (25%) was used as a reference surface sizing agent.

Use Example 1 Table 1 shows the test results of the size effect of the surface sizing agents obtained in Examples 1 to 3, Comparative Examples 1 and 2 and Reference Examples 1 and 2 on the neutral paper base paper.

<Size effect test conditions> Base paper pulp: L-BKP 100% Filler: Heavy calcium carbonate (ash content in paper 20%) pH: 9.5 (hot water extraction method) Basis weight: 64 g / m ² Stext size: 3 seconds (size internally added with alkenyl succinic anhydride) Surface sizing device: Lab size press Concomitant drug: Oxidized starch (applied amount 2.0 g / m ² , solid content) Drying: rotary auto dryer 105 ° C., 60 seconds As shown in Table 1, the surface sizing agent of the present invention exhibits a good sizing effect at a low application amount and a strong sizing effect at a large coating amount.

On the other hand, each of the comparative surface sizing agents of Comparative Examples 1 and 2 has a weak sizing effect and cannot obtain a strong sizing effect.

Further, the reference surface sizing agents of Reference Examples 1 and 2 all have little improvement in the size effect.

〔The invention's effect〕

The surface sizing agent of the present invention has an excellent sizing effect as compared with the conventional surface sizing agent. In particular, it is excellent in the effect on base paper which is neutral or alkaline. Not only the pen writing size but also the size effect in the Z direction of the paper, that is, the Steckigt sizing degree and the Cobb size are remarkably excellent. Furthermore, a satisfactory size effect can be obtained with a low coating amount, and the size cost can be significantly reduced. It can also be used in the field of paper that requires strong size.

As indicated above, the surface sizing agent of the present invention has (a)
It is a surface sizing agent composed of a water-soluble or water-dispersible polymer containing (b) together with other monomer units, and by using this, the size effect can be greatly improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display area C08F 220/12 MMA D 7242-4J MMB C 7242-4J

Claims (3)

[Claims] 1. (a) General formula (In the formula, R ₁ is hydrogen or a methyl group, and R ₂ is a hydrocarbon group having 4 or more carbon atoms.) A unit of a short chain ester of (meth) acrylic acid represented by the formula (b). (In the formula, R ₃ is hydrogen or a methyl group, and R ₄ has 8 to 2 carbon atoms.
4 is a unit of a long-chain ester of (meth) acrylic acid represented by an alkyl, aralkyl, or cycloalkyl group of 4), (c) the general formula Or (In the formula, R ₅ is hydrogen or a methyl group, and R ₆ has 1 to 2 carbon atoms.
4 hydrocarbon group or a hydrocarbon group containing an oxyalkylene group, A is an alkylene group having 2 to 4 carbon atoms, and n is 0 to 1
0, M ₁ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an amine cation. ), A unit of an unsaturated sulfonic acid (salt) monomer containing a (meth) allyl sulfosuccinate ester (salt), (d) a general formula (Wherein R ₇ is hydrogen or a methyl group, M ₂ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an amine cation), and a unit of an unsaturated carboxylic acid (salt) monomer and optionally ( e) A surface sizing agent characterized by comprising a water-soluble or water-dispersible polymer comprising units of another nonionic vinyl monomer. 2. The amount of (a) is from 1 to 8 based on the weight of the polymer.
Claim 1 wherein 0%, (b) is 1 to 70%, (c) is 0.1 to 50%, (d) is 1 to 70%, and (e) is 0 to 50%. Surface sizing agent. 3. The polymer has a molecular weight of 2,000 to 2,000.
The surface sizing agent according to claim 1 or 2, which is 50,000.