JP2541324C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]   The present invention relates to a gravure printing paper coating composition, and more particularly to a calendering process.
It is excellent in calender roll stain resistance during
The present invention relates to a gravure printing paper coating composition capable of obtaining a coated paper having a small amount of gravure printing paper. [Conventional technology]   Gravure printing is increasingly used in recent years because it provides vivid colors and deep images.
Has become widely used. In addition, the rotogravure printing method has spread,
Demand for coated paper for gravure printing has increased sharply in recent years as a result
You.   By the way, in gravure printing, ink is transferred from a concave hole in a printing plate to printing paper.
Gravure stamps represented by so-called misdots and poor dot reproducibility
Transfer defects unique to printing are likely to occur.   These transfer defects significantly impair the aesthetics of the printed matter and, consequently, the coating for gravure printing.
It significantly reduces the commercial value of the paper itself. Therefore, paper coating compositions have never been used before.
Improve gravure printing suitability of coated paper (misdot resistance and halftone dot reproducibility
Efforts have been made to improve).   Among them, the study of the binder is one of them, and many findings have already been obtained.
For example, reducing the amount of binder in the paper coating composition may make the coated paper less suitable for gravure printing.
Improves surface properties, but lowers surface strength,
The use of paper improves the gravure printability of coated paper, but in this case also
Insufficient surface strength [Paper Technical Journal, Vol. 38, No. 12, pages 18-23 (1
984)], the use of vinyl acetate / acrylate synthetic emulsions
It is known that the surface strength is weak regardless of the gravure printing suitability of the paper
. All of these improve the gravure printability and surface strength of the coated paper simultaneously.
Indicates that it is difficult to   Insufficient surface strength of the coated paper indicates that
Under-roll contamination, and removal of coated paper significantly reduces productivity.
This is a big problem because it becomes poor.   As described above, the binder used for conventional coated paper for gravure printing is
The balance of calender roll stain resistance and gravure printing characteristics in the finishing process during paper manufacturing
Lance was not enough at present. [Problems to be solved by the invention]   The present invention has been made in the background of the above-mentioned conventional technical problems, and has been developed for calendar processing. Gravure printing paper coated assembly with both excellent resistance to calendar stains and suitability for gravure printing
The purpose is to provide a product. [Means to solve the problem]   The first invention of the present invention provides a copolymer latex as a pigment and a binder.
In the gravure printing paper coating composition containing, the copolymer latex,   (A) 30 to 70% by weight of an aliphatic conjugated diene monomer,   (B) Ethylenically unsaturated monomers (however, ethylenically unsaturated carboxylic acid monomers
20-69.5% by weight,   (C) 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer,   Is obtained by emulsion polymerization in the presence of α-methylstyrene dimer.
Gravure printing paper coating composition characterized in that it is a copolymer latex.
I do.   The second invention of the present invention provides a copolymer latex as a pigment and a binder.
In the gravure printing paper coating composition containing, the copolymer latex,   (A) 30 to 70% by weight of an aliphatic conjugated diene monomer   (B) Ethylenically unsaturated monomers (however, ethylenically unsaturated carboxylic acid monomers
20-69.5% by weight   (C) 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer,   A monomer containing(A)Terpinolene, α-terpinene, γ-terpinene
At least one compound selected from dipentene and dipentene5 to 95% by weight, (B)
Alkyl mercaptans, carbon tetrachloride, xanthogen disulfides and thiu
From 95 to 5% by weight of at least one compound selected from lambdisulfides
Polymerization chain transfer agentIs a copolymer latex obtained by emulsion polymerization in the presence of
And a gravure printing paper coating composition.   Hereinafter, the present invention will be described in detail.   (A) The aliphatic conjugated diene-based monomer used for producing the copolymer latex of the present invention
Examples of the monomer include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene
Ene, 2-methyl-1,3-butadiene and the like, and preferably 1,3
-Butadiene. These monomers (a) may be used alone or in combination of two or more. Can be used in combination.   The monomer (a) imparts appropriate elasticity and film hardness to the obtained copolymer latex.
Component is indispensable for its content, and its proportion is 30 to 70% by weight, preferably 40 to 6% by weight.
5% by weight. If the proportion of the monomer (a) is less than 30% by weight, the flexibility of the copolymer and the
Insufficient adhesiveness, resulting in insufficient gravure printability and surface strength of the coated paper
On the other hand, if it exceeds 70% by weight, the tackiness of the copolymer increases,
Is unfavorable because the stain resistance is lowered.   Further, (b) the ethylenically unsaturated monomer includes an aromatic vinyl compound,
(Meth) acrylate, vinyl cyanide compound, ethylenically unsaturated acid amide,
Ethylenically unsaturated glycidyl ester, ethylenically unsaturated acid alcohol having a hydroxyl group
Ethylene-based compounds other than the monomer (C) component such as
And saturated monomers.   Among them, examples of the aromatic vinyl compound include styrene and α-methylstyrene.
, P-methylstyrene, vinyltoluene, chlorostyrene, etc.
Styrene is preferred.   As the alkyl (meth) acrylate, methyl (meth) acrylate
, Ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl
Sil (meth) acrylate, glycidyl (meth) acrylate, propyl (meth)
) Acrylate, octyl (meth) acrylate, benzyl (meth) acrylate
, Lauryl (meth) acrylate, stearyl (meth) acrylate, etc.
Of which methyl methacrylate, butyl acrylate, 2-ethyl
Hexyl acrylate is preferred.   Further, as the vinyl cyanide compound, acrylonitrile, methacrylonitrile
And acrylonitrile.
Are preferred.   As the ethylenically unsaturated acid amide, acrylamide, methacrylamide, N
-Methylol acrylamide, N-methylol methacrylamide, N-butoxy
Methyl acrylamide and the like, as ethylenically unsaturated glycidyl ester,
Glycidyl acrylate, glycidyl methacrylate, etc. Examples of the alkylene ester of a titren-based unsaturated acid include 2-hydroxyethyl acrylate
G, 2-hydroxypropyl acrylate 2-hydroxyethyl methacrylate
And the like.   In addition, if necessary, methacrylamidopropyltrimethylammonium chloride
Ride, hydroxypropyltrimethylammonium methacrylate chloride,
Quaternary ammonium such as acrylamidopropyl dimethyl ammonia acetate
Salt monomers can be used.   The monomer (b) preferably contains an aromatic vinyl compound as an essential component.
If necessary, one or more other monomers (b) are used. More preferred
Represents an aromatic vinyl compound and an alkyl (meth) acrylate and / or cyanide
A vinyl chloride compound as an essential component, and if necessary, another monomer (b).
Use one or more species.   The content of the aromatic vinyl compound in the monomer (b) is preferably at least 20% by weight.
And more preferably 30 to 90% by weight.   Further, as the monomer (b), an ethylenically unsaturated acid amide, an ethylenically unsaturated
Lysidyl ester and alkyl ester of ethylenically unsaturated acid having hydroxyl group
When the monomer selected from the above is used in an amount of 0.1 to 15% by weight based on all the monomers, the adhesive strength is reduced.
Improves calender roll stain resistance as it improves and further reduces tackiness.
It has the effect of improving.   These monomers (b) impart appropriate hardness, elasticity and water resistance to the copolymer.
And the amount of use is preferably 20 to 69.5% by weight based on the total monomers.
Or 30 to 45% by weight. If the amount of the monomer (b) is less than 20% by weight,
When the polymer becomes too soft, on the other hand, when it exceeds 69.5% by weight, on the contrary, it becomes too hard and adheres
Poor strength.   Further, (c) the ethylenically unsaturated carboxylic acid monomer includes, for example, itacone
Acids, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like can be mentioned.   These monomers (c) may be used alone or in combination of two or more.
It is preferable to combine appropriate amounts of acrylic acid and methacrylic acid
.   The amount of the monomer (c) used is 0.5 to 10% by weight based on all monomers, preferably 1 to 7% by weight. When the amount of the monomer (c) is less than 0.5% by weight,
Poor stability of the resin and easy formation of coagulated material.
When the strength is low, on the other hand, when it exceeds 10% by weight, the viscosity of the obtained latex increases,
Its handling (handling) becomes difficult, workability decreases, and lacks practicality
It will be.   The copolymer latex in the present invention comprises the above monomers (a) to (c) in an aqueous medium.
It can be obtained by emulsion polymerization in water.
In the presence of a polymerization chain transfer agent. That is, in the first invention of the present invention,
In the presence of α-methylstyrene dimer, preferably α-methylstyrene
Polymerization comprising 2 to 100% by weight of dimer and 0 to 98% by weight of another polymerization chain transfer agent
In the presence of a chain transfer agent, and in the second invention of the present invention, terpinolene,
at least one selected from α-terpinene, γ-terpinene and dipentene;
In the presence of the compound, preferably, (A) terpinolene, α-terpinene, γ-te
2 to 100% by weight of at least one compound selected from lupinene and dipentene
%, (B) alkyl mercaptans, carbon tetrachloride, xanthogen disulfide
At least one compound selected from the group consisting of benzenes and thiuram disulfides
The emulsion polymerization is carried out in the presence of a polymerization chain transfer agent consisting of% by weight.   The first and second inventions will be described in detail below.   The polymerization chain transfer agent (hereinafter referred to as polymerization chain transfer agent (I)) used in the first invention
) Is α-methylstyrene dimer and other polymer chains optionally used.
And a transfer agent.   As an α-methylstyrene dimer, (A) 2-4-diphenyl-4-methyl-1-pentene, (B) 2-4-diphenyl-4-methyl-2-pentene, and (C) 1-1-3-trimethyl-3-phenylindane There is. A preferred composition for the α-methylstyrene dimer is that the component (A) is 40
% Or more, and the component (b) and / or (c) component is 60% by weight or less, more preferably
More preferably, the component (a) is at least 50% by weight, the component (b) and / or the component (c)
50% by weight or less, particularly preferably 70% by weight or more of the component (A) and the component (B) And / or component (c) is 30% by weight or less. (A) The composition ratio of the components is high
The better the chain transfer effect, the better.   α-Methylstyrene dimer is an impurity, for example, as long as the object of the present invention is not impaired.
For example, unreacted α-methylstyrene, α-methyl styrene other than the components (a), (b) and (c)
Even if it contains a methylstyrene oligomer or an α-methylstyrene polymer
Good.   If α-methylstyrene dimer is used, it does not impair its purpose.
If the α-methylstyrene dimer is synthesized, use it in a partially purified state.
Can also.   Other polymerization chain transfer agents used in combination with α-methylstyrene dimer include general
Known polymerization chain transfer agents used in emulsion polymerization can be used. Concrete
Specifically, for example, octyl mercaptan, n-dodecyl mercaptan, t-dode
Silmercaptan, n-hexadecylmercaptan, n-tetradecylmercaptan
Mercaptans such as tan and t-tetradecyl mercaptan; dimethylxanthate
Gendisulfide, diethylxanthogendisulfide, diisopropylxan
Xanthogen disulfides such as togen disulfide; tetramethylthiuram
Disulfide, Tetraethylthiuram disulfide, Tetrabutylthiuramdis
Thiuram disulfides such as sulfide; halo such as carbon tetrachloride and ethylene bromide
Genated hydrocarbons; hydrocarbons such as pentaphenylethane; and acrolein
, Methacrolein, allyl alcohol, 2-ethylhexyl thioglycolate
, Terpinolene, α-terpinene, γ-terpinene, dipentene, etc.
be able to. These may be used alone or in combination of two or more.
it can. Of these, mercaptans, xanthogen disulfides, thiura
Mudisulfides, carbon tetrachloride and the like are preferably used.   The proportion of the α-methylstyrene dimer in the polymerization chain transfer agent (I) is preferably 2
To 100% by weight, more preferably 3 to 100% by weight, particularly preferably 5 to 95% by weight.
%.   When the proportion of the α-methylstyrene dimer is less than 2% by weight, the object of the present invention is considered.
Coalex latex with excellent calender roll stain resistance and excellent gravure printability I can't get it. Also, α-methylstyrene dimer and another polymerization chain transfer agent
The reactivity at the time of polymerization can be enhanced by the combined use of the above.   The amount of the polymerization chain transfer agent (I) to be used is usually 0.05 to 100 parts by weight of all monomers.
20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.3 to 7 parts by weight.
You. If the amount of the polymerization chain transfer agent (I) used is less than 0.05 parts by weight, it is suitable for gravure printing.
On the other hand, if it exceeds 20 parts by weight, the adhesive strength and the calender roll stain resistance will be poor.
Inferior.   In addition, about the usage-amount of (alpha) -methylstyrene dimer, the total monomer 100 weight
It is preferably used in the range of 0.1 to 5 parts by weight per part.   Next, the polymerization chain transfer agent used in the second invention (hereinafter referred to as the polymerization chain transfer agent (
II)) are (A) terpinolene, α-terpinene, γ-terpinene and
At least one compound selected from dipentene and dipentene (hereinafter referred to as “component (A)”
) And (B) other polymerization chain transfer agents, if necessary,
Rumercaptans, carbon tetrachloride, xanthogen disulfides and thiuramdi
At least one compound selected from sulfides (hereinafter referred to as “component (B)”
U).   Specific examples of the alkyl mercaptans of the component (B) include the mercapta described above.
And the same compounds as the compounds. Of these, t-dodecyl mercap
Tan is preferably used.   Specific examples of xanthogen disulfides and thiuram disulfides include
Similar to the previously described xanthogen disulfides and thiuram disulfides
Compounds can be mentioned.   The proportion of the component (A) in the polymerization chain transfer agent (II) is preferably 2 to 100% by weight,
It is more preferably 3 to 100% by weight, particularly preferably 5 to 95% by weight. component
When the component (B) is used in combination with the component (A), the calender roll stains aimed at by the present invention are obtained.
A paper coating composition excellent in both resistance and gravure printing suitability can be obtained.   The amount of the polymerization chain transfer agent (II) to be used is usually 0.05 to 2 per 100 parts by weight of all monomers.
0 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.3 to 7 parts by weight.
. If the amount of the polymerization chain transfer agent (II) is less than 0.05 part by weight, the suitability for gravure printing is poor.
, If the amount exceeds 20 parts by weight, the adhesive strength and the calender roll stain resistance are inferior.
It becomes   The amount of component (A) used is 0.1 to 5 parts per 100 parts by weight of all monomers.
It is preferably used in the range of parts by weight.   The copolymer latex in the present invention comprises the above monomer and polymerization chain transfer agent.
Except for use, it can be produced by a conventionally known emulsion polymerization method.
That is, a monomer mixture and a polymerization initiator, an emulsifier,
It can be obtained by adding a polymerization chain transfer agent or the like and conducting emulsion polymerization.   There is no particular limitation on the polymerization initiator used for the emulsion polymerization in the present invention.
For example, cumene hydroperoxide, diisopropylbenzene hydroperoxy
Hydroperoxides such as side and paramenthane hydroperoxide
, Peroxides such as benzoyl peroxide and lauroyl peroxide
Polymerization of azo compounds and azo compounds such as azobisisobutyronitrile
Agents such as potassium persulfate, sodium persulfate and ammonium persulfate
An inorganic polymerization initiator such as a sulfate can be used.   In the present invention, a copolymer obtained by using an organic polymerization initiator alone is used.
The mechanical stability of TEX is poor, and a large amount of coagulated material is generated during polymerization.
, An inorganic polymerization initiator alone or in combination with an organic polymerization initiator.
Preferably.   The above polymerization initiator was used in combination with a reducing agent such as sodium bisulfite.
It can also be used as a so-called redox polymerization initiator.   Among these polymerization initiators, persulfates such as potassium persulfate and ammonium persulfate
Salt or azobisisobutyronitrile or benzoyl peroxide
And combinations of these with reducing agents are preferably used.
It is.   The amount of the polymerization initiator used in the present invention is usually 0.1 parts per 100 parts by weight of the gold monomer.
To 5 parts by weight, preferably 0.5 to 2 parts by weight. Inorganic polymerization initiator and organic
When used together with a system polymerization initiator, the ratio of the organic polymerization initiator is preferably
It is at most 70% by weight, more preferably at most 50% by weight of the polymerization initiator. Organic When the ratio of the polymerization initiator exceeded 70% by weight, the organic polymerization initiator was used alone.
Problems such as the case occur, which is not preferable.   There is no particular limitation on the emulsifier used for the emulsion polymerization in the present invention.
Any of nonionic, nonionic and amphoteric surfactants can be used. This
These can be used alone or in combination of two or more. For example,
Sulfuric acid ester salts of higher alcohols such as sodium lauryl sulfate, dodecylben
Alkylbenzene sulfonates such as sodium benzene sulfonate, dioctyls
Sulfonates of aliphatic carboxylic esters such as sodium rusuccinate
Anionic surfactant, alkyl ester type of polyethylene glycol, alkyl
Nonphenyl surfactants such as phenyl ether type and alkyl ether type
Can be used. In addition, as an amphoteric surfactant, cation is used as an anion part.
Rubonates, sulfates, sulfonates, phosphates, phosphates,
Further, those having an amine salt or a quaternary ammonium salt as the cation portion may be mentioned.
Can be. Specifically, as the salt of alkyl betaine, lauryl betaine,
Allyl betaine, cocoamidopropyl betaine, 2-undecylhydroxyethyl
Louisimidazolium betaine salt, and lauryl as an amino acid type
-Β-alanine, stearyl-β-alanine, lauryldi (aminoethyl) glycol
Syn, octyldi (aminoethyl) glycine, dioctyldi (aminoethyl) glycine
Lysine salts can be mentioned.   Of these emulsifiers, alkyl benzene sulfonate is particularly preferably used.
You. More specifically, sodium dodecylbenzenesulfonate is particularly preferred.
Used properly. This alkyl benzene sulfonate can be used with other surfactants, such as
Sulfates of higher alcohols, sulfonates of aliphatic carboxylic esters
Anionic surfactants such as polyethylene glycol alkyl esters
Nonionic interface such as alkyl type, alkyl ether type and alkyl phenyl ether type
You may use together with an activator etc.   The amount of the emulsifier used is usually 0.05 to 2 parts by weight per 100 parts by weight of all monomers,
Preferably it is 0.05 to 1 part by weight. If the amount of the emulsifier exceeds 2 parts by weight,
Poor properties, and foaming of the paper coating composition becomes remarkable, which causes a problem during coating. In addition, Alkylbenzenesulfonate with other anionic or nonionic surfactants
When used together, the proportion of alkylbenzene sulfonate used is 50% by weight of the total emulsifier
% Or more is preferable.   In the emulsion polymerization, in addition to the polymerization chain transfer agent, polymerization initiator, emulsifier, etc.,
A seed electrolyte, a pH adjuster, etc. are used in combination, and 100 parts by weight of the monomers (a) to (c) are added.
On the other hand, 100 to 300 parts by weight of water and the polymerization chain transfer agent, emulsifier, polymerization initiator, etc.
When used in an amount within the above range, the polymerization temperature is 5 to 90 ° C, preferably 30 to 70 ° C,
Emulsion polymerization is performed under polymerization conditions for a total time of 15 to 30 hours.   The method of adding each of the monomers (a) to (c) is not particularly limited.
Any method such as a batch addition method, a continuous addition method, or a split addition method is employed, but it is preferable.
More preferably, the semi-batch method described below is preferred.   That is, (a) (c) part or all of the ethylenically unsaturated carboxylic acid monomer
5 to 45% by weight, preferably 10 to 35% by weight of all monomers including
And emulsion polymerization up to a polymerization conversion rate of 20 to 90% by weight, preferably 30 to 70% by weight.
(First stage), (b) then 55 to 95% by weight of all monomers, preferably 65 to 9%
Emulsion polymerization by adding the remaining monomer equivalent to 0% by weight continuously or intermittently.
And the instantaneous polymerization conversion rate until the addition of the gold monomer is completed.
Is always 20 to 90% by weight per monomer added by the corresponding time,
30 to 85% by weight, and the polymerization conversion at the end of the addition of all the monomers is 50 to 9
Emulsion polymerization so as to be 0% by weight, preferably 60 to 85% by weight (second stage)
.   In the first step, (c) part or all of the ethylenically unsaturated carboxylic acid monomer
It is preferred to use a part of this monomer (c) when it is used only in the second stage.
The adhesiveness and water resistance of the obtained latex are not improved.   In addition, the amount of the monomer (c) to be charged in the first stage is 5% by weight of all the monomers.
%, A stable latex cannot be obtained.
There is a tendency for coagulated material to be generated therein and industrial productivity to be significantly deteriorated.   Further, if the polymerization conversion of the monomer polymerized in the first stage is less than 20% by weight,
When a stable latex is not obtained, and when it exceeds 90% by weight, the viscosity of the obtained latex
Wear And water resistance are inferior.   In the second step, the monomers (a) to (c) are added all at once during the emulsion polymerization.
In this case, the generation of coagulated material in the obtained latex becomes remarkable. Also, the addition of this monomer
During the addition, the instantaneous polymerization conversion is temporarily less than 20% by weight or 90% by weight.
%, The adhesive strength and water resistance of the obtained latex decrease, which is preferable.
Absent.   Further, in this second stage, the polymerization conversion after the completion of the monomer addition is 50% by weight.
If the amount is less than the above, the amount of the monomer remaining after the addition of the monomer becomes large,
In the same state as the case, the occurrence of coagulated material in the obtained latex is remarkable,
On the other hand, if the productivity is extremely deteriorated, on the other hand, if it exceeds 90% by weight, the desired effect of the present invention is obtained.
Can not be obtained.   In the most preferred embodiment of the second stage emulsion polymerization method, the remaining monomers are instantaneously used.
The polymerization conversion at the time is maintained in the range of 30 to 85% by weight, and after completion of the monomer addition.
Divide continuously or into three or more parts so that the polymerization conversion rate is 60 to 85% by weight.
Can be added.   The gel content of the copolymer latex used in the present invention is determined by the copolymer latex.
Excellent adhesive strength and tackiness of the box, and excellent resistance to stains on calendar rolls
Therefore, it is preferably in the range of 85 to 98% by weight.   Further, the particle size of the copolymer latex used in the present invention is usually 700 to 2300
Angstroms, preferably 1200-1800 Angstroms.   Examples of the pigment used in the present invention include clay, talc, calcium carbonate, oxidized
Titanium, mineral pigments commonly used for paper coating such as satin white and
And organic pigments such as polymer particles and hollow polymer particles.
Or two or more are used.   The gravure printing paper coating composition of the present invention contains the pigment as a pigment binder as a pigment binder.
Polymer latex and, if necessary, casein, starch, cellulose, polyvinyl
Natural or synthetic binders such as alcohol, alkali thickening emulsions
And a thickener.   In addition, the compounding amount of the copolymer latex is usually based on 100 parts by weight of the pigment. It is 3 to 12 parts by weight, preferably 4 to 8 parts by weight in terms of solid content.   The gravure printing paper coating composition of the present invention generally has a solid content of 50 to 7%.
0% by weight, preferably about 55 to 65% by weight, and the viscosity is usually 1500 to 3000 c.
ps, preferably 1500 to 2500 cps.   The gravure printing paper coating composition of the present invention further includes various commonly used gravure printing paper coating compositions.
Compounding agents, for example, a water resistance improver, a water resistance reaction accelerator, a pigment dispersant, a viscosity modifier,
A coloring pigment, a fluorescent dye, a pH adjuster, and the like can be arbitrarily added. [Example]   Hereinafter, the present invention will be described in more detail with reference to Examples.   In the examples, “parts” and “%” are based on weight unless otherwise specified.
is there.   Further, various test methods in the examples are as follows.   Misdot ratio (index of gravure printing suitability)   Using the Ministry of Finance Printing Bureau-type gravure printing tester (manufactured by Kumagai Riki Co., Ltd.)
The test pieces were printed using dot gravure. The number of missed dots is the total number of halftone dots
Defined as a percentage of and expressed as a percentage. The smaller the numerical value, the better.   Dry strength (index of adhesive strength)   The degree of picking when printing with an RI printing machine is judged with the naked eye, and evaluated in five steps
did. The higher the score, the better the dry strength. With the average value of 6 measurements
Show.   Calendar roll dirt resistance   Laminate the aluminum sheet on the coated surface of the coated paper before super calendar
After passing through 0 ° C, 250kg / cm output render, coated paper and aluminum sheet
The aluminum sheet was peeled off, and the degree of contamination of the aluminum sheet was indicated by gloss reduction (%). Small number
It shows that there is very little dirt.Examples 1 to 10 (Production of copolymer latex)   In a 100-liter pressure-resistant reaction vessel, the monomer, water, and polymer
After charging the chain transfer agent, the emulsifier, and the polymerization initiator in this order, the mixture is heated to a temperature of 70 in a nitrogen atmosphere. Polymerization was carried out at 2 ° C. for 2 hours. Next, the second stage water, emulsifier, and polymerization initiator are charged in this order.
After that, the second stage monomer and polymerization chain transfer agent are added continuously over 8 hours
To carry out polymerization. Thereafter, the reaction was continued for another 3 hours to complete the polymerization.
The polymerization was completed at a polymerization conversion of 98%.   After adjusting the obtained copolymer latex to pH 7.5 using sodium hydroxide,
, Steam is blown to remove unreacted monomers, and solid
Ten kinds of copolymer latexes having a concentration of 50% were obtained. These are described in Examples 1 to 10
I do.   The α-methylstyrene dimer used here and the following comparative examples
The α-methylstyrene dimer is as follows. Product name: NOFMER MSD (manufactured by NOF Corporation)composition         Composition name Composition (% by weight)   2-4-diphenyl-4-methyl-1-pentene 92.0% or more   2-4-diphenyl-4-methyl-2-pentene 5.0% or less   1-1-3-trimethyl-3-phenylindane 1.5% or less   α-methylstyrene 1.0% or less   The gel content of the copolymer latex was adjusted to pH 8.5 for each copolymer latex.
After coagulation, coagulation with methanol, washing and drying, a predetermined amount (about 0.3 g)
It was immersed in 100 ml of toluene for 20 hours, and the toluene insoluble content was measured.
It is a value expressed in% by weight. Table 1 shows the measurement results. (Preparation of paper coating composition)   Using each copolymer latex thus obtained, the following formulation (A)
Alternatively, a cord coating composition was prepared according to (B).Formulation (A)                                                     (Part) Kaolinite Clay (Hydro Sparse, manufactured by J.M. Huber) 100 Dispersant (Alon T-40, manufactured by Toa Gosei Co., Ltd.) 0.2 Sodium hydroxide 0.1 Carboxymethyl cellulose (Daiichi Kogyo Seiyaku Co., Ltd., Cellogen PR) 0.3 Copolymer latex 8 Water (adding appropriate amount so that total solid content is 60%)Formulation (B)                                                     (Part) Kaolinite Clay (Hydro Sparse, manufactured by J.M. Huber) 100 Dispersant (Alon T-40, manufactured by Toa Gosei Co., Ltd.) 0.2 Sodium hydroxide 0.1 Synthetic water retention agent * 1 0.5 Copolymer latex 7.5 Water (adding appropriate amount so that total solid content is 60%) * 1 The one obtained in Example 1 of JP-A-59-154133 was used.   To these compositions, an appropriate amount of aqueous sodium hydroxide solution is further added, and each composition is added.
The pH of the product was adjusted to 9.0. (Production of coated paper)   Each of the obtained compositions was subjected to 54 kg / m^TwoElectric blade coater (bear
Tani Riki Co., Ltd.) and the coating amount is 13 ± 0.5 g / m on one side^TwoCoating so that
Dried for 15 seconds in a gear open at 20 ° C. The coated paper obtained is kept at 20 ° C. and relative humidity.
Leave it in the room condition of 65% of the temperature all day and night, and then apply a linear pressure of 250 kg / m.^Two, Roll temperature 5
The super calender treatment was performed four times at 0 ° C., and the above-described tests were performed. Conclusion
The results are shown in Table 3.   Examples 1 to 5 correspond to the first embodiment, and Examples 6 to 10 correspond to the second invention.
Gravure printing, which is a corresponding example, and all have the effects intended by the present invention
A paper coating composition has been obtained.Comparative Examples 1 to 6   The polymerization was carried out in the same manner as in Example 1 except that the polymerization recipe shown in Table 2 was used.
Six types of copolymer latex which do not belong to the present invention were obtained. These are referred to as Comparative Examples 1 to 6.   Next, using the above copolymer latex, the gel content was obtained in the same manner as in Example 1.
And the physical properties of the coated paper were evaluated. The results are shown in Table 2 and Table 4.
Show.   Comparative Examples 1 and 2 are comparative examples corresponding to the first invention, and Comparative Examples 3 and 4 are second comparative examples.
Comparative Examples 5 and 6 correspond to the first and second inventions. This is a comparative example.   Comparative Example 1 is an example in which the butadiene content of the copolymer latex exceeds the range of the present invention.
Yes, poor in calender roll stain resistance.   Comparative Example 2 is an example in which the butadiene content of the copolymer latex is less than the range of the present invention.
And the suitability for gravure printing is poor.   Comparative Example 3 is an example in which the butadiene content of the copolymer latex is less than the range of the present invention.
And the suitability for gravure printing is poor.   Comparative Example 4 is an example in which the butadiene content of the copolymer latex exceeds the range of the present invention.
Yes, poor in calender roll stain resistance.   Comparative Example 5 is an example in which only carbon tetrachloride was used as a chain transfer agent.
-Poor roll stain resistance.   Comparative Example 6 is an example using only t-dodecyl mercaptan as a chain transfer agent.
Yes, poor gravure printing suitability. [The invention's effect]   The present invention relates to a specific polymerization as a pigment binder of a gravure printing paper coating composition.
By using a copolymer latex obtained by polymerization in the presence of a chain transfer agent,
Render roll stain resistance, gravure printability, and dry strength are well-balanced and excellent
A gravure printing paper coating composition is obtained, which is suitable for the production of gravure printing coated paper.
Can be used.

Claims (1)

Claims: (1) In a gravure printing paper coating composition containing a pigment and a copolymer latex as a binder, the copolymer latex comprises: (a) an aliphatic conjugated diene monomer 30 to 70% by weight, (b) ethylenically unsaturated monomer (excluding ethylenically unsaturated carboxylic acid monomer) 20 to 69.5% by weight, (c) ethylenically unsaturated carboxylic acid monomer 0 A gravure printing paper coating composition, which is a copolymer latex obtained by emulsion polymerization of a monomer containing 0.5 to 10% by weight in the presence of α-methylstyrene dimer. (2) In a gravure printing paper coating composition containing a pigment and a copolymer latex as a binder, the copolymer latex contains: (a) an aliphatic conjugated diene-based monomer 30 to 70% by weight (b) 20 to 69.5% by weight of an ethylenically unsaturated monomer (excluding an ethylenically unsaturated carboxylic acid monomer), and (c) 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer. (A) 5-95 % by weight of at least one compound selected from terpinolene, α-terpinene, γ-terpinene and dipentene;
Alkyl mercaptans, carbon tetrachloride, xanthogen disulfides and thiu
From 95 to 5% by weight of at least one compound selected from lambdisulfides
A gravure printing paper coating composition, which is a copolymer latex obtained by emulsion polymerization in the presence of a polymerization chain transfer agent .