JPH02140271A - Hollow polymer pigment and coating composition using the pigment - Google Patents

Abstract

PURPOSE:To provide the subject pigment composed of a hollow polymer particle having outer and inner layers respectively consisting of a specified polymer, suitable for a coating material for paper, woodworking products, metal goods, building materials, etc., and capable of providing a coating film excellent in opacifying properties, gloss, water resistance, etc. CONSTITUTION:The subject hollow polymer particles pigment consisting of a hollow polymer particle composed of two or more polymer layers and having (A) 0.15-20mum average particle diameter, (B) 0.2-0.8 average ratio of equivalent hollow diameter to equivalent particle diameter of respective particles, (C) 20-90wt.% ratio of toluene-insoluble portion and (D) 0.1-1g/10min. melt flow rate at 180 deg.C and 10kgf/cm<2> where (E) the inner layer of the above-mentioned two polymer layers is consisting of a crosslinked polymer composed of (i) a polymerization unit of formula I (n is 2 or 3), (ii) another polymerization unit of formula II (Y is phenyl, etc.) and (iii) the other polymerization unit of formula III. And the outer layer of the above-mentioned particle is consisting of a non- crosslinked polymer composed of the components (ii) and (iii).

Description

Detailed Description of the Invention "Field of Application in Industry-1-" (a) The first invention relates to a hollow polymer pigment.More specifically, it relates to a hollow polymer pigment.
This invention relates to a new pigment suitable for general paints used for building materials, structures, walls, floor coverings, etc.

(b) The second invention relates to a novel paper coating composition that provides offset printing coated paper or gravure printing coated paper with excellent properties. More specifically, the present invention includes:
To obtain a coated paper with excellent whiteness, opacity, and printability, and an excellent balance of white paper gloss and print gloss required for offset printing, and halftone reproducibility and print gloss required for gravure printing. The present invention relates to a paper coating composition that can be used.

(c) The third invention relates to a lightweight coating composition that provides a coating film with excellent hiding properties, gloss, water resistance, alkali resistance, heat resistance, etc., and is also excellent in handling and stability.

[Prior art] (a) Pigments made of fine polymer particles are known;
It has not yet reached widespread use. In recent years, it has become possible to produce hollow polymer particles, and their use as microcapsules and paint pigments is being considered.

Conventionally, as a method for producing polymer particles having inner pores,
The following methods are known.

(I) A method in which a foaming agent is contained in polymer particles and the foaming agent is then foamed.

(II) encapsulating a volatile substance such as butane in the polymer,
A method to later gasify and swell this volatile substance.

(m) A method in which a polymer is melted and a jet of gas such as air is blown onto it to seal in air bubbles.

(IV) A method of infiltrating an alkali-swellable substance into the interior of polymer particles to swell the alkali-swellable substance.

(V) A method of preparing a w10/w type monomer emulsion and conducting polymerization.

(VI) A method in which monomers are polymerized in a suspension solution in which a pigment is suspended in an unsaturated polyester solution.

(■) A two-step crosslinking method in which crosslinked polymer particles are used as seeds and polymers with different compatibility are polymerized and crosslinked onto the seeds.

(■) A method of manufacturing by polymerization shrinkage of a polymer.

(b) In recent years, along with the rapid increase in the number of printed materials, the demand for offset printing paper and gravure printing paper has also increased significantly. Coated paper used in offset printing is required to have excellent white paper gloss and printing gloss. Coated paper used for gravure printing is also required to have good halftone dot reproducibility and excellent printing gloss. Improving the physical properties listed above required for coated paper for printing will improve the finish of printing and significantly increase the commercial value of coated paper.

Traditionally, kaolin and clay have been widely used as pigments in paper coating compositions because of their superior gloss and printability of coated paper. The use of titanium oxide as a white pigment has been introduced to increase the whiteness and opacity of However, coated paper containing titanium oxide in a paper coating composition has the disadvantage that it is inferior to coated paper without titanium oxide in terms of gloss, printability, strength, etc. In addition, the special public
In Publication No. 6524, a paper coating liquid formulation containing 0.
It has been reported that improvement in white paper gloss and print gloss can be achieved by mixing organic pigments with a particle size of 3 to 0.8 microns, but this method has the disadvantage of poor whiteness and opacity. be. As mentioned above, there is no paper coating liquid composition that can produce coated paper with excellent gloss, strength, and printability, as well as excellent whiteness and opacity using conventional methods. Ta.

In addition, in recent years, it has become necessary to improve the solidity of coating liquid compositions, so that the effect of improving the fluidity of coating liquids is significant. It is used mixed with heavy calcium carbonate, kaolin, clay, etc. Furthermore, as there is a trend toward neutralizing paper in the future, it is expected that heavy calcium carbonate will be increasingly used. However, when heavy calcium carbonate is used as a pigment, there is a problem that halftone reproducibility and print gloss, which are important characteristics of gravure printing and offset printing, are impaired. Various attempts have been made to solve this problem. JP-A-57-167490 and JP-A-57-7739
In Publication No. 4, when heavy calcium carbonate is used as a pigment, when an alkali-sensitive copolymer latex is used in combination as a pigment binder (adhesive),
- It has been reported that printing problems can be alleviated and coated paper can be given high stiffness, good halftone dot reproducibility, and print gloss. However, by simply improving the pigment binder in this way, there is a limit to increasing the ratio of heavy calcium carbonate to the total pigment, and it is not possible to achieve the objectives of improving coating workability and achieving high solid content. It is enough.

(c) It has been suggested in the past that microvoid-containing polymer particles can act as a masking agent or opacifying agent in paints and molding compositions.

Although U.S. Pat. No. 3,819,542 does not disclose anything about the production of microvoided polymer particles that function as opacifiers in coating compositions, it does disclose the use of organic solvents in latex coating compositions. There is some empirical interest in showing that, upon drying, the molecule produces a cellular film. More specifically, the U.S. patent discloses a primary organic solvent (e.g., xylene) that is immiscible with the aqueous phase of the latex coating composition, and a secondary organic solvent (e.g., propylene glycol). At least in part, admixtures are used with polymers that are immiscible in water and have a lower volatility and solvation ability than the primary solvent for the polymer in the latex. Evaporation of the primary solvent results in a cellular film, the secondary solvent increasing its opacity.

In U.S. Pat. No. 3,819,577, vesicular polymers are prepared by converting a solid polymer into a liquid medium containing therein dispersed granules of other polymers swollen with a liquid swelling agent. Application of the composition to the substrate then simultaneously forms a paint film and removal of the swelling agent from the swollen dispersed polymer forms vesicles within the granules.

However, although these paint compositions have good hiding properties, they have poor gloss and film strength, and are associated with health and fire hazards and the need to provide expensive solvent drainage and/or recovery equipment. Canadian Patent No. 888.129 discloses a two-stage latex dispersion process of granules having a core containing a blowing agent and a sheathing layer. The granules are continuously heated to generate gas and foam the granules.

However, with this method, it is difficult to form uniform, minute pores, and a strong coating cannot be obtained.

U.S. Pat. No. 3,914,338 describes infant polymer granules consisting of a cross-linked styrene emulsion polymer of particle size greater than 0.8 microns and having a sheath of methyl methacrylate polymer thereon by a subsequent emulsion polymerization step. A manufacturing method is disclosed. Infantility is due to the different refractive indices of the core and sheath.

However, the hiding power of the baby polymer particles obtained by this method is not as good as the hiding power due to micro voids.

Australian Patent No. 455,277 discloses that an aqueous dispersion of a pigment is suspended by droplets in a solution of an unsaturated polyester containing an unsaturated monomer such as styrene, and the resulting suspension is placed in the form of beads in water. dispersed in and then polymerized,
In addition, water-based coating compositions based on water-soluble polymers, such as those containing bead-shaped resin particles stabilized by the addition of partially hydrolyzed polyvinyl acetate, or unsaturated polyester resins with polyethylene oxide chains. An improved composition (Japanese Patent Application Laid-open No. 129485/1983) has been provided which uses the above composition without adding a water-soluble polymer.

However, although these coating compositions have hiding properties, they have the disadvantage of producing coatings with poor gloss.

JP-A-56-32513 discloses an aqueous dispersion of core/shell polymer particles containing 5% by weight or more of an unsaturated carboxylic acid monomer in the core and 0% by weight or less in the shell, and the sheath component is ammonia or 1%. Alternatively, coating compositions have been provided that utilize core/shell polymer particles that are permeable to volatile bases such as organic amines and that upon neutralization cause swelling of the core. In water-based coating compositions, the particles function as a binder or part thereof and, upon use, are at least partially neutralized (minimum pH
6), the polymer particles provide rheological control of the coating composition and form voids within the core of the swollen particles in the coating during drying of the coating composition, acting as an opacifying agent. There is.

However, in order to form microvoids using this method, the glass transition temperature (Tg) of the shell must be set above room temperature, preferably above 50°C, and must function as a binder or a part of it within the coating film. However, if the Tg of the shell layer is set below room temperature in order to impart a binder function, the shell loses its external shape during the process in which volatile bases and endocellular water are removed from the core of the swollen particles when the coating composition dries. It cannot be maintained and collapses, forming micro voids.
＜It is difficult to make it function as an opacifying agent.

For the above reasons, it has the disadvantage that it is difficult to simultaneously function as an opacifying agent and as part of a binder.

JP-A No. 60-223873 proposes a method in which a core/shell resin emulsion having internal voids formed by crosslinking both the core and shell components is utilized as an opacifying agent in a water-based paint.

However, since the core/shell polymer particles obtained by this method have very small internal voids and are non-film forming at room temperature, when such particles are used in aqueous paint compositions, gloss However, since it does not have a binder function, it has drawbacks such as low paint film strength.

[Problems to be Solved by the Invention] (a) In conventionally known methods for producing hollow polymer particles, it is difficult to control production conditions or to stably produce polymer particles having desired internal pores. In addition, when conventional hollow polymer particles are added as pigments to coating film-forming substances, they have the required physical properties of hiding properties, but they also have poor gloss, coating strength, elasticity, adhesion, water resistance, and alkali resistance. , the balance of physical properties such as weather resistance was poor. In particular, in the conventional manufacturing method of hollow polymer particles,
In order to develop internal pores in polymer particles, it is necessary to use a shell polymer with a high glass transition temperature, but this has the fatal effect of not being able to obtain hollow polymer pigments with good adhesion. It had some problems.

The present invention provides a hollow polymer pigment that solves the problems of the prior art.

(b) The present invention solves the problems of the prior art described above, and provides coated paper with excellent whiteness and opacity, as well as white paper gloss, printing gloss, coated paper strength, and printability. The purpose of the present invention is to provide a coating liquid composition for paper that can be used. In addition, a paper coating liquid composition with a high content of heavy calcium carbonate for high solids content takes advantage of the characteristics of heavy calcium carbonate, which has excellent flow properties, while also improving glossiness, printing performance in offset printing and gravure printing. An object of the present invention is to provide a paper coating composition that provides coated paper with excellent properties.

(c) The present invention solves the problems of the prior art as mentioned above, and when used in a coating composition, it has excellent hiding properties and gloss, and the strength of the coating film, water resistance, alkali resistance, The purpose of the present invention is to provide a general-use coating composition using a hollow polymer pigment that is excellent in handling and coating properties.

[Means for Solving the Problems] (b) The object and advantage of the present invention in item 1 is to provide a hollow polymer pigment comprising hollow polymer particles having at least two polymer layers, the hollow polymer pigment comprising hollow polymer particles having at least two polymer layers. The particles (1) have an average particle size in the range of 0.15 to 20 μm, (2) have an average ratio of equivalent hollow diameter to equivalent particle size for each particle in the range of 0.2 to 0.8, (3) The proportion of the toluene-insoluble portion is 20 to 90% by weight, (4) The melt flow rate under the condition of 180° C11C11O/cm2 is 0.1 to 1 g/10 min,
(5) The inner layer of the two-layer polymer layer in 1- is represented by the following formula (a) (where R1 is a hydrogen atom r or methyl 1.5,
X is an n-functional organic group or a bond, and n is a number of 2 or 3, provided that n R1s may be the same or different, and X is a bond In the case of hands, n is 2. ) Polymerized monomer (\°L, the following formula (b) (where R2 is a hydrogen atom or a methyl group, and Y is a phenyl group, or substituted with a halogen atom, an alkyl group, or a vinyl group) or a halogen atom, an ano group, an alkanoyloxy group having 1 to 18 carbon atoms, an alkoxy group, pyridyl, pyridylalkyl, aminoalkoxy, or an amide j1 (is). , the following formula (c) 3 R5 --[C----C1-... (c) R' C0
OR' (where R3 and R5 are the same or different and are a hydrogen atom or a methyl group, R4 is a hydrogen atom, a carboxyl group or a carboxylate group, R6 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, It is a hydroquine alkyl group having 2 to 10 carbon atoms, a white group having at least each member selected from glycidyl, amino, cyano and carbon-carbon double bonds, or one equivalent of a base. ) and, depending on the case, the following formula (d) p? (Here, R7 is a hydrogen atom or a methyl group.) It consists of a crosslinked polymer consisting of a polymer unit represented by the following, and (6) the outer layer of the above two-layer polymer has the above formula (b), (c
The present invention provides a hollow polymer pigment characterized by comprising a non-crosslinked polymer comprising at least one polymer unit selected from the group consisting of (a) and (d).

(b) The present invention provides 100 parts by weight of a pigment consisting of 1 to 50% by weight of the hollow polymer pigment, 50 to 99% by weight of a mineral inorganic pigment, and 0 to 25% by weight of a non-hollow polymer pigment, and 3 to 30% by weight of a pigment binder. Parts by weight of a paper coating composition are provided.

That is, in the present invention, pre-hollow polymer particles have a hard structure in which the inner pores are not easily deformed during pressurization and heating during calendering in the coated paper manufacturing process, and inorganic pigments and pigment binders are blended on the surface of the pre-hollow polymer particles. By using hollow polymer particles, which are composed of a polymer layer with excellent dispersion stability and excellent bonding properties, as a new synthetic organic pigment in combination with mineral inorganic pigments and pigment binders, coatings can be improved. It is possible to simultaneously improve the whiteness, opacity, white paper gloss, printing gloss, coated paper strength, printability, etc. of paper. Furthermore, when the composition has a high content of heavy calcium carbonate, glossiness and printing characteristics in gravure printing and offset printing can be significantly improved.

(c) The present invention includes 3 to 95 parts by weight of a hollow polymer pigment and 5 to 97 parts by weight of a pigment binder (100 parts by weight in total).
and 700 parts by weight or less of an inorganic filler.

That is, in the present invention, a viaduct, a high T.
The inner layer is made of polymer particles having pores of 1.5 g, and the outer layer has a copolymer coating formed from a monomer mixture appropriately selected according to the light intensity required for the light source, the binder function, etc. By blending a new hollow polymeric resin, which has internal voids large enough to exhibit high opacity, as a pigment into a paint composition,
It has good coating properties and formulation stability, and can significantly improve hiding properties, gloss, film strength, and resistance such as water and alkali resistance.

The present invention will be explained in detail below.

(a) The hollow polymer particles (Q) of the present invention are (m-1
) Consists of a crosslinked polymer consisting of polymerized units of the above formulas (a), (b), and (c) and optionally further polymerized units of (d), and has an average t+'x J'-diameter of 0.05 to 15
Hollow polymer particles in the range of l1m (hereinafter sometimes referred to as pre-hollow polymer particles (P)), and (n]-2) of the following formula (bl) C1(□-c (bl) (where R2 and The definition of Y is the same as in the above formula (b).

) and the following formula (cl) 3 R1 (here, R3, R4, R5, RG are defined as 1-formula (c
) is the same as ) and the following formula (dl) CH2=CR7-CH=C1t-I2 (di)
(Here, the definition of R7 is the same as in the above formula (d).) At least one monomer selected from the group consisting of monomers represented by the above pre-hollow polymer particles (P) and the monomer It can be produced by subjecting it to polymerization in an aqueous medium at a pH of less than 7 in the presence of 5 parts by weight or less of an emulsifier and/or a dispersant per 100 parts by weight of the body (m2).

” Pre-hollow polymer particles (P
), as mentioned above, the above formulas (a), (b), (c)
It consists of the polymerized unit of (d) and optionally the polymerized unit of (d), and has an average particle diameter in the range of 0.05 to 15 μm.

Pre-hollow polymer particles (P) are, for example, disclosed in JP-A-61-62
510 and JP-A No. 61-66710, and the method (■) shown in the conventional technical section, as well as JP-A No. 61-87734, JP-A No. 61-8694), JP-A-62 It can be suitably manufactured by the method (■) shown in the prior art section proposed in Japanese Patent Laid-open No. 127336, Japanese Patent Laid-Open No. 62-15637, etc. By using pre-hollow polymer particles obtained by such a method, hollow polymer particles (Q) of the present invention having particularly excellent hiding properties can be obtained.
can be manufactured. In particular, according to the method (■), it is easy to control the inner diameter and outer diameter of the obtained pre-hollow polymer particles (P), and by using it, it is possible to improve not only the hiding property but also the solvent resistance and heat resistance. It is also possible to produce the hollow polymer pigment of the present invention which is also excellent in terms of . (■
) is particularly preferred. Of the methods (■), the method disclosed in Japanese Patent Application Laid-open No. 127336/1988 is most preferred.

According to this method, further excellent polymerization stability and productivity can be achieved in the polymerization of pre-hollow polymer particles (P).

Thus, according to the invention, the pre-hollow polymer particles (
P) has the following formula (al) p+ (where R1 is a hydrogen atom or a methyl group, X is an n-functional organic group or a bond, and n is a number of 2 or 3) , However, n R1s may be the same or different, and if X is a bond, n is 2
It is. ) A monomer represented by the following formula (bl) CI+. -C . monomer represented by the following formula (c1) R' GOOR (Here, R3 and R5 are the same or 5'4, and are a hydrogen atom or a methyl group, R4 is a hydrogen atom, a carboxyl group, or a carboxylate group, and R6 is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. , a hydroxyalkyl group having 2 to 10 carbon atoms, or an organic group having at least one member selected from glycidyl, amino, cyano, and a carbon-carbon double bond, or one equivalent of a base), and optionally Accordingly, the following formula (dl) CH2=C-CH=CH2...(di) (where R
7 is a hydrogen atom or a methyl group. ) A monomer mixture (m-1) of the monomers represented by is combined with another polymer (hereinafter sometimes referred to as a heterogeneous polymer (S)) having a composition different from that of the polymer from this monomer mixture. ) particles, 1 of the other polymer particles per 100 parts by weight of the monomer mixture (m-1)
It can be produced by polymerization in an aqueous medium using a proportion of ~100 parts by weight.

Examples of the monomer represented by the above formula (al) include divinyl monomers or trivinyl monomers such as divinylbenzene, ethylene glycol dimethacrylate, 1,3 butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate. can do. Particularly preferred are divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate.

Examples of the monomer represented by the above formula (bl) include styrene, α-methylstyrene, p-methylstyrene, ethylstyrene, vinyltoluene, halogenated styrene,
Aromatic vinyl monomers such as vinylnaphthalene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 2-methyl-1-pentene, 4-methyl-1-pentene; vinyl fluoride, Vinyl halides such as vinyl bromide; vinyl cyanide compounds such as acrylonitrile and methacrylate; vinyl acetate; vinyl organic acids such as vinyl propionate and vinyl stearate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Amide monomers such as acrylamide, methacrylamide, and N-methylolmethacrylamide; alkenylpyridines such as vinylpyridine and propenylpyridine; aminoalkyl vinyl ethers such as aminoethyl vinyl ether, dimethylaminoethyl vinyl ether, and dimethylaminoethyl vinyl ether. I can give an example.

Examples of the monomer represented by the above formula (cl) include unsaturated mono- or dicarboxylic acid monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid; Acid anhydrides; (meth)acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, butyl methacrylate, and lauryl methacrylate; crotonate efsters, itacon Dicarboxylic acid monoesters or diesters such as monomethyl acid and dimethyl maleate;
2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, β-hydroxyethyl (
Hydroxy alkyl esters of ethylenically unsaturated carboxylic acids such as meth)acrylate; amino group-containing alkyl esters of ethylenically unsaturated carboxylic acids such as methylaminoethyl (meth)acrylate and dimethylaminopropyl (meth)acrylate; cyanomethyl Cyano group-containing alkyl esters of tonoethylenically unsaturated carboxylic acids such as acrylate and 2-cyanoethyl acrylate;
Aminoalkylamides of ethylenically unsaturated carboxylic acids, such as methylaminoethyl (meth)acrylamide and dimethylaminoethyl (meth)acrylamide, (meth)
Examples include glycidyl esters of ethylenically unsaturated carboxylic acids such as glycidyl acrylate.

As the monomer represented by the above formula (dl), for example, 1
, 3-butadiene, 2-methyl-1,3-butadiene, 2
-Aliphatic conjugated diene monomers such as -chloro-1,3-butadiene can be exemplified.

In addition, the above-mentioned polymer (heterogeneous polymer (S)) used when producing pre-hollow polymer particles (P) from these monomers includes monomers (m A polymer that is different from the polymer in -1) and that is easily dissolved or swelled in the above monomer is preferably used.

Specific examples of such different polymers include polystyrene, carboxy-modified polystyrene, carboxy-modified styrene-butadiene copolymer, styrene-butadiene copolymer, styrene-acrylic ester copolymer,
Examples include styrene methacrylic ester copolymer, acrylic ester copolymer, methacrylic ester copolymer, carboxy-modified styrene acrylic ester copolymer, carboxy-modified styrene methacrylic ester copolymer, carboxy-modified acrylic ester copolymer and carboxy-modified methacrylic ester copolymer.

Of these, polystyrene or styrene components are particularly
Styrene copolymers containing 0% by weight or more are preferred.

The pre-hollow polymer particles (P) are the above (al) and (bl)
The above heterogeneous polymer (S) is added to 100 parts by weight of a monomer mixture (m-1) consisting of a monomer represented by (c1) and, optionally, a monomer represented by (dl).
It is produced by using 1 to 100 parts by weight, preferably 2 to 50 parts by weight, more preferably 5 to 20 parts by weight, and subjecting them to polymerization in an aqueous medium.

If the amount of the different polymer used is less than 1 part by weight, the effect of forming inner pores will be small, and if the amount of the different polymer used exceeds 100 parts by weight, the formation of inner pores will tend to be suppressed, which is not preferable.

Therefore, a particularly preferable method for producing pre-hollow polymer particles (P) is to use monomers ( Based on the sum of al), (bl), (cl) and (dl), monomer (al) 1-80% by weight, monomer (b
Hydrophilic monomers selected from l) and (c1) 20~
99% by weight and monomers (bl), (cl) and (d
This method uses a monomer mixture consisting of 0 to 70% by weight of other copolymerizable monomers selected from 1).

Examples of the hydrophilic monomer selected from monomers (bl) and (c1) include vinylpyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, methacrylamide,
N-methylol acrylamide, N-methylol methacrylamide, acrylic acid, methacrylic acid, itaconic acid,
Examples include fumaric acid, sodium styrene sulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypyl methacrylate.

Among these, those preferably used include unsaturated carboxylic acids such as methacrylic acid, methyl methacrylate, vinylpyridine, and 2-hydroxyethyl methacrylate. The solubility of these hydrophilic monomers in water is preferably 0.5% by weight or more, particularly 1% by weight or more.

Further, the other copolymerizable monomers selected from the monomers (bl), (cl), and (dl) can be used without particular limitation, but aromatic vinyl compounds such as those exemplified above, Ethylenically unsaturated carboxylic acid alkyl esters, vinyl cyanates, and aliphatic conjugated dienes are preferred, particularly styrene, methacrylic acid alkyl esters having an alkyl group having 3 or more carbon atoms, and methacrylic acid having an alkyl group having 2 or more carbon atoms. Alkyl esters are preferred.

A more preferable composition of the monomer mixture (m-1) is:
2 to 60% by weight of monomer (al) (crosslinking monomer), 40 to 98% by weight of a hydrophilic monomer selected from monomers (bl) and (c1), and monomers (bl), (cl) and ( dl) Other copolymerizable monomers selected from 0-
It is 70% by weight.

If the amount of hydrophilic monomer used is too small, the phase separation of the different polymers (S) may be insufficient, or the different polymers may be exposed on the surface of the polymer particles, resulting in uncertain formation of inner pores. This is not preferable because it shows a tendency to Additionally, if the amount of crosslinking monomer used is too small, the strength of the particles during polymerization will be insufficient and the entire particle will shrink.
Problems such as insufficient strain due to polymerization shrinkage inside the particles, resulting in no internal pores being formed, or even if polymer particles having internal pores are formed, the strength of the shell is reduced, tend to occur.

On the other hand, if the amount of crosslinking monomer used is too large, different types of polymers tend to be excluded to the outside of the polymer particles formed during polymerization, and as a result, the resulting polymer particles are not perfectly spherical and have irregularities. This results in some lumpy particle problems.

A preferred embodiment of the method for producing pre-hollow polymer particles (P) is as follows. This preferred embodiment is based on the polymerization technique of JP-A-62-127336, in which (A) a monomer mixture and optionally an oily substance is absorbed into fine particles of a different type of polymer (seed polymer). Then, the monomer mixture is polymerized, or (B) a different polymer is dissolved in the monomer mixture and, if necessary, an oily substance to form an oily solution, and this oily solution is finely dispersed in water to form an oil-in-water solution. Produce a droplet emulsion,
This is a method in which the above monomer components are then polymerized. As mentioned above, the presence of an oily substance together with a different type of polymer makes it easier to control the diameter of the inner pores of the polymer particles.

When the foreign polymer (S) is used in the form of particles by the method (A) above, the foreign polymer (S) functions as a seed polymer particle and the monomer mixture and oily substance are absorbed therein. Preferably, the polymer has good absorption of monomer mixtures and oily substances. For this reason, it is preferable to use a heteropolymer having a small molecular weight; for example, the number average molecular weight is 20,000 or less, preferably 10,000 or less, and more preferably 700 to 7,000. Note that the number average molecular weight here refers to dissolving a different type of polymer in its good solvent and using the resulting solution using a conventional method such as gel permeation chromatography (GPC), an osmotic pressure molecular weight measuring device, or a vapor pressure lowering molecular weight measuring device. It can be obtained by measuring using the method described below.

If the number average molecular weight of the different polymer is greater than 20,000, there will be a large amount of monomer that will not be absorbed by the seed polymer particles, and this will polymerize separately with the seed polymer particles in the aqueous dispersion, resulting in fine particles that will not form polymer particles with internal pores. This not only tends to be produced in large amounts, but also causes the problem that the polymerization system becomes unstable.

Further, the particle diameter of the different polymer used as the seed polymer particles is preferably 0.3 to 0.8 times the outer diameter of the intended pre-hollow polymer particles (P).

There are no particular restrictions on the method for producing the dissimilar polymer used as such seed polymer particles, but for example, it can be produced using a production method such as emulsion polymerization or suspension polymerization using a relatively large amount of a chain transfer agent. .

In addition, when using a different type of polymer as the seed polymer particles, by pre-absorbing a highly lipophilic substance having a solubility in water of 10-3% by weight or less into the seed polymer particles, the monomer for the seed polymer particles can be absorbed. The absorption capacity of mixtures and oily substances can be increased.

When using a method of absorbing a highly lipophilic substance into the seed polymer particles as described above, favorable results can be obtained even when the number average molecular weight of the different polymer exceeds 20,000.

Examples of the highly lipophilic substance include 1-chlordodecane, octanoyl peroxide, and 3,5°5-trimethylhexanoyl peroxide.

In order to absorb these highly lipophilic substances into the seed polymer particles, for example, an aqueous dispersion in which the highly lipophilic substance is finely dispersed is prepared, and this dispersion is mixed with an aqueous dispersion of the seed polymer particles. It is preferable to bring the highly lipophilic substance and the seed polymer particles into contact with each other.

The particle diameter of the pre-hollow polymer particles (P) with inner pores obtained when seed polymer particles are used is approximately the particle diameter of particles enlarged by the seed polymer particles absorbing polymerizable monomers and oily substances. Match. Therefore, it is possible to control the particle size of the pre-hollow particles with internal pores by adjusting the particle size of the seed polymer particles and the relative amount of the seed polymer particles used relative to the monomer mixture and oily substance. can.

Specifically, in the production of pre-hollow polymer particles (P) having inner pores, 0, 1 to
In order to obtain pre-hollow polymer particles with a particle size of 0.6 μm, seed polymer particles with a particle size of 0.06 to 0.40 μm may be used.

Another advantage of using seed polymer particles is that the particle size is 1
Another advantage of this method is that when producing polymer particles having internal pores with a small particle size of .mu.m or less, monomer droplets with a small particle size can be easily and stably formed.

When using a different type of polymer in the method (B) above,
The molecular weight of the different polymer is not particularly limited, and those having a number average molecular weight of 20,000-L or more can be preferably used.

In this manufacturing method (B), an oily substance can be used if necessary. Such oily substances are not particularly limited as long as they are lipophilic and have a solubility in water of 0.2% by weight or less, and any of vegetable oils, animal oils, mineral oils, and synthetic oils can be used.

In this production method (B), pre-hollow polymer particles having inner pores can be obtained without using an oily substance, but by using an oily substance and adjusting the amount used, the diameter of the inner pores can be increased. can be reliably controlled.

Examples of the oily substance include lard oil, olive oil,
Examples include coconut oil, castor oil, cottonseed oil, kerosene, benzene, toluene, xylene, butane, pentane, hexane, cyclohexane, carbon disulfide, and carbon tetrachloride.

Further, as the oily substance, high boiling point oils such as eugenol, geraniol, cyclamenaldehyde, citronellal, dioctyl phthalate, and dibutyl phthalate can also be used. When these high boiling point oils are used, capsule-like polymer particles containing perfume, plasticizer, etc. in the core can be obtained.

The amount of oily substance used is usually 0 to 1,000 parts by weight, preferably 0 to 300 parts by weight per 100 parts by weight of the monomer mixture.
Parts by weight. Incidentally, inert solvents normally contained in those supplied as crosslinkable monomer materials can also be included as oily substances here. If the amount of the oily substance used is too large, the monomer component will be relatively insufficient and the thickness of the outer shell of the polymer will become thin, causing the problem that the strength of the capsule will be insufficient and it will be easily crushed.

In addition, the concept of the oily substance includes the already mentioned monomer (a
l), (bl), (cl) and (dl). In this case, in the polymerization step, by stopping the polymerization with the monomer remaining inside the produced polymer particles, the remaining monomer can be used as an oily substance. In this case, the polymerization yield must be kept at 97% or less, preferably 95% or less. For this purpose, methods such as adding a small amount of polymerization inhibitor to polymerize, lowering the temperature of the reaction system during polymerization, or adding a polymerization terminator during polymerization to stop polymerization can be adopted. .

In addition, in this production method (B), capsule-shaped polymer particles containing an oily substance or water-containing hollow polymer particles obtained by replacing the oily substance with water as described above are separated from the aqueous dispersion and subjected to drying treatment. By doing so, pre-hollow polymer particles having spaces inside are obtained.

The pre-hollow polymer particles (P) obtained using the polymerization technique described in 1. have the following advantages.

(1) The manufacturing process is simple and has excellent productivity.

(ii) Production control is easy, and pre-hollow polymer particles having the desired outer and inner diameters can be obtained.

(iii) Since the pH of the aqueous dispersion of pre-hollow polymer particles can be freely selected, it can be used without restriction as a monomer for the polymer formed on the surface of the pre-hollow polymer particles.

(iv) By using these pre-hollow polymer particles as the pre-hollow polymer particles (P) in the method of the present invention, the hollow polymer pigment of the present invention obtained has - far superior hiding properties;
Indicates gloss, adhesion, and film strength.

According to the present invention, the average particle diameter is 0.05 to 15 μm, preferably 0°15 to 10 μm, by the method described in “-”.
m pre-hollow polymer particles (P) can advantageously be produced.

Particles having an average particle diameter of less than 0.05 μm are difficult to produce, and even if they can be produced, they are not preferred because they contain at least a portion of polymer particles that do not have hollow spaces. on the other hand,
If the outer diameter exceeds 15 μm, the particle size distribution becomes broad, and the hollow polymer pigment of the present invention obtained by using these as pre-hollow polymer particles (P) cannot be obtained with uniform particle sizes, which is not preferable.

The ratio of the inner diameter to the outer diameter of the pre-hollow polymer particles (P) is preferably 0.25 to 0.9 times. If it is 0.25 times or more, hollow polymer particles with even better physical properties, which are the object of the present invention, can be obtained, so it is preferable. On the other hand, if it exceeds 0.9 times, the production of pre-hollow polymer particles (P) becomes difficult. becomes difficult,
This is not preferable for industrial production.

Further, the pre-hollow polymer particles (P) preferably have a room temperature toluene insoluble content of 80% by weight or more, and the glass transition temperature Tg is 150° C. or more or cannot be measured.

As described above, the pre-hollow polymer particles (P) in the present invention have a composition of a crosslinked polymer consisting of polymerized units (a), (b), (c) and optionally (d).

Preferable pre-hollow polymer particles (P) in the present invention are:
According to the preferred manufacturing method described above, (i) polymerized units (
Based on the total of a), (b), (c) and (d), 20 to 99% by weight of the hydrophilic polymerized unit selected from the polymerized units (b) and (c), and 1% of the polymerized unit (a) -80% by weight and a crosslinked polymer consisting of 0 to 70% by weight of other copolymerizable units selected from polymerized units (b), (c), and (d), and (ii) the above copolymer. is a polymer of different composition (S
), (iii) ``100 parts by weight of polymer (i),
1. The polymer (if) has a composition of 1 to 100 parts by weight. More preferably, component (i) is 40 to 98% by weight of hydrophilic polymerized units, 2 to 60% by weight of polymerized units (a), and 0 to 70% by weight of other copolymerizable polymerized units.
It consists of

The type of hydrophilic polymerized units in component (1) is not particularly limited, but preferably consists of polymerized units derived from unsaturated carboxylic acids and/or other hydrophilic monomers.

(1) The hydrophilic polymerized units in the component are more preferably composed of unsaturated carboxylic acids and/or other hydrophilic monomers, and the composition ratio thereof is 1 to 70 polymerized units derived from unsaturated carboxylic acids. % by weight and 30 to 99% by weight of polymerized units derived from other hydrophilic monomers.

By using pre-hollow polymer particles (P) having these preferred or more preferred component (f), according to the present invention, hollow polymer pigments with even more excellent physical properties as the object of the present invention can be produced. Can be done.

As described above, the hollow polymer particles (Q) of the present invention are made by combining the pre-hollow polymer particles (P) with a monomer (m2), that is, a group consisting of monomers (bl), (cl) and (dl). As a mixture with at least one selected from It can be produced by subjecting it to polymerization in a medium under conditions where the pH is less than 7.

Monomer (bl) used as monomer (m-2), (
c1) and (dl) are pre-hollow polymer particles (
The same as described above for P) can be used. Among the monomers (bl), those preferable as component (m-2) include aromatic vinyl monomers such as styrene and p-methylstyrene; vinyl cyanide compounds such as acrylonitrile; and halogens such as vinyl fluoride. organic acid vinyl such as vinyl acetate; and amide monomers such as acrylamide. Particularly preferred is styrene.

The amount of monomer (bl) used is based on the total of component (m-2), preferably 7 to 99.5% by weight, more preferably 10 to 99.5% by weight, particularly preferably 20 to 99.5% by weight. 99.5
Weight%. This is preferable from the viewpoint of light scattering properties and gloss imparted to the hollow polymer pigment of the present invention.

Among monomers (c1), preferred as component (m-2) are unsaturated mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid; methyl (meth)acrylate, (meth)acrylic acid (Meth)acrylic acid ester monomers such as ethyl, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; dicarboxylic acid mono- or diesters such as monomethyl itaconate and dimethyl maleate; 2-hydroxyethyl These include hydroxyalkyl esters of ethylenically unsaturated carboxylic acids such as (meth)acrylate; glycidyl esters of ethylenically unsaturated carboxylic acids such as glycidyl (meth)acrylate;

Particularly preferred are (meth)acrylic acid, itaconic acid, (
Methyl acrylate, ethyl (meth)acrylate,
These are butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate.

The amount of monomer (c1) used is based on the total of components (m-2), and is preferably 0. 5 to 100% by weight, more preferably 0.5 to 90% by weight, particularly preferably 0.5 to 80% by weight
iT'+, 'IA%.

Further, as the monomer (c]), preferably 0.5 to 50% by weight, more preferably 1 to 50% by weight of unsaturated carboxylic acids such as (meth)acrylic acid and itaconic acid, based on the total of the ('m2) components. It is preferable to use 40% by weight, particularly preferably 2 to 30% by weight, since polymerization stability can be obtained.

In addition, in place of a part of the monomer (c1), a carboxyl group
The molecular weight of each unsaturated carboxylic acid monomer is 10
0 or more-1-unsaturated carboxylic acids can also be used. Examples of these are shown below in the form of general formulas. Use of this unsaturated carboxylic acid further improves the strength and adhesive properties of the hollow polymer pigment of the present invention.

■ R,,, -C-C-C00H R,21-3 (Here, Rh, R12, RI3 are H or have 1 to 2 carbon atoms
0 alkyl group. ) is a propylene oxide group. ) 0OH (wherein, ) Among these higher carbonic acid monomers, the following formula (in the above two formulas, RI4, RSS, and R16 are H
or an alkyl group having 1 to 12 carbon atoms, EO is an ethylene oxide group, and PO is particularly preferred.

Among the monomers (dl), 1,3-butadiene is particularly preferred as the (m-2) component.

The amount of monomer (dl) used is based on the total of components (m-2), preferably 0 to 80% by weight, more preferably 0 to 6% by weight.
0% by weight, particularly preferably 0 to 50% by weight. The hollow polymer pigment of the present invention is preferred from the viewpoint of strength, adhesiveness, and balance of weather resistance, light resistance, and heat resistance.

The calculated Tg of the copolymer of the monomer mixture (m-2) used for producing the hollow polymer particles of the present invention is preferably 40 to 150°C. The temperature is particularly preferably 40 to 100°C when the particles are strongly required to have strength, adhesiveness, pigment bonding properties, etc., and 70 to 150°C is particularly preferable when the particles are strongly required to have gloss and light scattering properties.

The polymerization step is carried out in the presence of 5 parts by weight or less of an emulsifier and/or dispersant per 100 parts by weight of the total weight of the pre-hollow polymer particles (P) and the monomer mixture (m-2), under conditions where the pH is less than 7, and water. carried out in the medium. A monomer or a monomer mixture (
m-2) with an average particle diameter of 0.
Hollow polymer particles (Q) of the present invention are formed in the range of 15 to 20/Jm.

In the polymerization process, monomers or monomer mixtures (m
-2) As for the addition method, pre-hollow polymer particles (P)
and a monomer or monomer mixture (m-2) are stirred and mixed for polymerization, and the monomer mixture (m-2) is continuously or dividedly supplied to a polymerization system in which pre-hollow polymer particles (P) are present and polymerized. There is an incremental polymerization method that performs the following steps. Increment polymerization is preferred in order to efficiently and stably copolymerize the polymerizable monomer onto the surface of the pre-hollow polymer particles.

As emulsifiers and/or dispersants (suspending agents),
Any of anionic, nonionic, cationic, and amphoteric types can be used.

These can be used alone or in combination of two or more.

Emulsifiers include, for example, rosinate salts such as potassium rosinate and sodium stearate; aliphatic sodium and potassium salts and lauryl sulfate such as potassium oleate, potassium laurate, sodium laurate, sodium stearate, and potassium stearate. Sulfate ester salts of aliphatic alcohols such as sodium; anionic emulsifiers such as alkylaryl sulfonates such as sodium dodecylbenzenesulfonate, sodium dialkyl sulfosuccinates, and formalin condensate salts of naphthalene sulfonic acid; alkyl esters of polyethylene glycol;
Nonionic emulsifiers such as alkyl ether type and alkylphenyl ether type are preferred. Among them, sodium lauryl sulfate, sodium dodecylbenzenesulfonate,
Preferred are sodium dioctyl sulfosuccinate, formalin condensate salt of naphthalene sulfonic acid, and alkylphenyl ether type of polyethylene glycol.

Examples of cationic emulsifiers include quaternary ammonium salt type emulsifiers, and when the aqueous dispersion is made into a cationic emulsifier, they are used alone or in combination with nonions.

Examples of dispersants include hydrophilic synthetic polymer substances such as polyacrylic acid, polymethacrylic acid, polyvinyl sulfonic acid, polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol; natural hydrophilic polymer substances such as gelatin and water-soluble starch; Examples include hydrophilic semi-synthetic polymeric substances such as carboxymethylcellulose.

The amount of emulsifier and/or dispersant used is 5 parts by weight or less,
The amount is preferably 2 parts by weight or less, more preferably 1 part by weight or less. If the amount exceeds 5 parts by weight, the production efficiency of the hollow polymer particles of the present invention decreases due to the generation of new particles during polymerization, and furthermore, the hiding power and gloss decrease, which is not preferable.

Examples of polymerization initiators include organic hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, sugar-containing pyrophosphate formulations, sulfoxylate formulations, and sugar-containing pyrophosphate formulations. A redox initiator in combination with a reducing agent, typified by mixed formulations of sulfoxylate formulations; persulfates such as potassium persulfate and ammonium persulfate; azobisisobutyronitrile, benzoyl peroxide,
Lauroyl peroxide or the like can be used.

Preferably, a persulfate such as potassium persulfate or ammonium persulfate, azobisisobutyronitrile, or benzoyl peroxide is combined with a reducing agent if necessary. Particularly preferred are persulfates such as potassium persulfate and ammonium persulfate. Since radicals of these polymerization initiators tend to concentrate on the surface of the pre-hollow polymer particles, the formation of a film by the (m2) component is carried out efficiently. The amount of polymerization initiator is preferably 0.05 to 2 parts by weight, more preferably 0.0 parts by weight, based on the total amount of pre-hollow polymer particles (P) and monomer or monomer mixture (m-2).
It is 5 to 0.8 parts by weight.

When used within this range, hollow polymer particles of the present invention having excellent water resistance and alkali resistance can be obtained.

The polymerization temperature is usually 5 to 95°C, particularly preferably 50 to 90°C.

Other chain transfer agents may be used in combination if necessary.

Examples of chain transfer agents include mercaptans such as t-dodecylmercaptan, octylmercaptan, n-tetradecylmercaptan, and t-hexylmercaptan;
Examples include halogen compounds such as carbon tetrachloride and ethylene bromide.

In the emulsion polymerization of the present invention, depending on the pH of the polymerization system, the polymerization stability and the particle system distribution of the hollow polymer particles of the present invention,
It depends to a large extent on the inner diameter/outer diameter ratio. When the pH is lower than 7, the above items are satisfactory and the desired hollow particles of the present invention can be obtained. When the pH exceeds 7, if the monomer or monomer mixture (m-2) does not contain a polymerizable unsaturated carboxylic acid, the item 1. is undesirable because it tends to reduce polymerization stability.

As the pre-hollow polymer particles (P), the above-mentioned JP-A-62-1
When using the aqueous dispersion of hollow fine particles obtained by the method disclosed in Publication No. 27336, since its pH is 7 or less, the monomer of the polymer to be formed on the surface of the hollow fine particles can be used without restriction, and is extremely effective. preferable.

Thus, according to the present invention, as described in 1., hollow polymer particles having at least two polymer layers, (1) have an average particle diameter in the range of 0.15 to 20 μm, and (2) ) the average ratio of equivalent hollow diameter to equivalent particle diameter for each particle is in the range of 0.2 to 0.8; (3) the proportion of toluene-insoluble portion is 20 to 90% by weight; (4) 180 The melt flow rate under the condition of °C 110 kg f/c♂ is 0.1 to Ig/min,
(5) The inner layer of the above two polymer layers has the following formulas (a) and (b)
), (c) and optionally (d), and (6) the outer layer of the two-layered polymer has the formulas (b), (c)
There is provided a hollow polymer pigment of the present invention, characterized in that it is made of a non-crosslinked polymer comprising at least one polymer unit selected from the group consisting of () and (d).

The average particle diameter of the hollow polymer pigment of the present invention is in the range of 0.15 to 20 μm, as described above.

Those with an average particle diameter of less than 0.15 μm have poor hiding properties when used as a light scattering aid, and those with an average particle diameter of more than 20 μm have poor polymerization stability (and also have poor monomer (m-2
) are generated, making it impossible to achieve the desired balance between various physical properties, including concealment and gloss.

The average particle size of the hollow polymer pigment of the present invention is preferably in the range of 0.2 to 2 μm.

Further, the average value of the ratio of equivalent hollow diameter to equivalent particle diameter for each particle is in the range of 0.2 to 0.8.

If this ratio is less than 0.2, the hiding power will be considerably poor, which is undesirable, and if it exceeds 0.8, the balance between hiding power, adhesiveness, gloss, and strength will be poor, which is not preferred.

Preferably, this ratio is between 0.4 and 0.75.

The equivalent hollow diameter means the diameter of a hollow portion when converted into a sphere, and similarly, the equivalent particle diameter means the diameter of a particle when the particle is converted into a sphere. The average value of these ratios is determined, for example, for 50 randomly selected particles.

The hollow polymer pigment of the present invention has a toluene-insoluble portion of 20 to 90% by weight, preferably 20 to 80% by weight. In addition, the melt flow rate is 0.1 to Ig/
10min (180°C11C11O/cIll)
and preferably 0.1 to 0.8 g/10 min.

Further, the compositions of the inner layer and outer layer of the polymer are as described above, and the ratio thereof is preferably 5 to 2,000 parts by weight of the inner layer per 100 parts by weight of the outer layer, and more preferably 5 to 2,000 parts by weight of the inner layer per 100 parts by weight of the outer layer. The amount is 10 to 1,000 parts by weight.

The outer layer preferably has a Tg of 40 to 150°C,
The Tg of the inner layer does not exist below 150°C.

Furthermore, the hollow polymer pigment of the present invention has a portion soluble in tetrahydrofuran, and the number average molecular weight of the portion is 700 in the molecular weight distribution measured by high performance liquid chromatography as a tetrahydrofuran solution.
-20,000 in an amount of 1 to 80% by weight, based on the sum of the parts dissolved in tetrahydrofuran.

The hollow polymer pigment of the present invention is produced as an aqueous dispersion according to the production method described in 1.

There is no limit to the solids content of the aqueous dispersion of hollow polymer pigments of the present invention, but it is usually preferably 10 to 65% based on the solids content of the formulation for each application.

The presence of pores in the polymer particles of the aqueous dispersion of hollow polymer pigment of the present invention can be confirmed, for example, by using a transmission electron microscope or by measuring specific gravity.

The aqueous dispersion of hollow polymer pigment obtained in the present invention can be powdered by drying. Powderization is
It can be powdered by a commonly used method for powdering an aqueous dispersion. For example, spray drying at 1309C to 180C,
For example, tray drying at 50 to 70°C in a hot air atmosphere, or fluidized bed drying at room temperature to 70°C. The solid content of the aqueous dispersion before drying is preferably 20% or more. The particle size of the obtained powder of the aqueous dispersion of the present invention is approximately the same as the particle size of the aqueous dispersion used.

The powder thus obtained can also be used in organic solvent-based paints if it is insoluble in organic solvents.

(b) The components used in the paper coating composition of the present invention will be explained below.

(1) Mineral inorganic pigments include clay, talc, satin white, heavy calcium carbonate, precipitated calcium carbonate, titanium dioxide, zinc oxide, aluminum hydroxide, barium sulfate, and the like. The amount of mineral inorganic pigment used in the present invention is 50 to 99 parts by weight, preferably 70 to 97 parts by weight, based on 100 parts by weight of the total pigment. In addition, in order to improve opacity and whiteness, it is preferable to use 1 to 10 parts by weight of titanium dioxide. There are no particular restrictions on the type or proportion of these mineral inorganic pigments, but for the purpose of improving fluidity when increasing the solids content of a paper coating composition, heavy calcium carbonate may be added to the entire pigment. The content is preferably 15% by weight or more.

(ij) Solid Polymer Pigment At the same time as the hollow polymer pigment, the solid polymer pigment
-40% by weight (based on the total pigment) can be used in combination. This polymer pigment is polystyrene, polymethyl methacrylate, a carboxy modified product thereof, a copolymer thereof, a crosslinked polymer thereof, or a polymer fine particle having a glass transition temperature of 60° C. or higher. These manufacturing methods are described in Japanese Patent Publication No. 47-25862 (US 4075134).
, Special Publication No. 51-125147 (US 396831
), Special Publication No. 5:3-7964 (US 38733)
45) etc. are known. The amount of hollow and non-hollow polymer pigments used in the total pigment ranges from 1 to 50% by weight, preferably from 3 to 30% by weight. If the amount used is less than 1% by weight,
No effect as a white pigment can be obtained, and if the amount exceeds 50% by weight, printability and coated paper strength will be poor. Polymer pigments 1-5
0 parts by weight, solid polymer pigments are 0 to 25 parts by weight,
Preferably, the weight is equal to or less than that of the hollow polymer pigment.

(iii) Pigment binder The pigment binder used in the present invention is not particularly limited and can be used as long as it is a binder used in ordinary paper coating solutions. Examples of the pigment binder include starch, modified starch, natural binders such as casein, styrene-butadiene copolymer latex, and carboxy-modified styrene-based binders.
Synthetic binders include butadiene copolymer latex, polyvinyl acetate emulsion, acrylic resin emulsion, polychloroprene latex, and polyvinyl alcohol, and these can be used alone or in combination of two or more. Among these pigment binders, styrene-butadiene copolymer latex and carboxy-modified styrene-butadiene copolymer latex are preferably used alone or in combination with a natural binder such as starch or casein.

The amount of pigment binder used is 3 to 100 parts by weight of pigment.
30 parts by weight are used. If the amount used is less than 3 parts by weight, the effect as a binder will not be obtained, while if the amount used exceeds 30 parts by weight, the viscosity of the coating composition will increase by -1- and the coating workability will be impaired. is inferior.

(iv) Coating method The above-mentioned components of the present invention are mixed and prepared by a conventional method, and applied to a paper substrate by a conventional coating method, such as an air knife coater, a blade coater, or a roll coater.

(c) The components used in the general-use coating composition of the present invention will be explained below.

(i) Pigment binder Any material that can be used as a binder for a water-based paint composition can be used without particular limitation, such as vinyl resin emulsion, vinyl water-soluble resin, vinyl resin dispersion, hydroxyethyl cellulose, Celluloses such as carboxymethyl cellulose, starch, casein, etc. are used.

Among these, it is preferable to use acrylic and acrylic-styrene resin emulsions from the viewpoint of weather resistance and coating strength, and their toluene insolubility is 30% or more and Tg is 150°C or higher and 40°C or higher. It is preferable that it is less than If toluene insoluble powder is less than 30%, solvent resistance and durability will be poor, if Tg is less than 50°C, stain adhesion and coating film strength will be poor, and if Tg is less than 40°C, film forming property and low-temperature properties of the coating film will be deteriorated. , the temperature dependence becomes inferior, which is not preferable.

The amount of these film-forming binders used is 5 to 97 parts by weight, preferably 10 to 95 parts by weight, more preferably 30 to 95 parts by weight.
It is 90 parts by weight. If it is less than 5 parts by weight, the binder strength will be insufficient and film formation will be difficult, and if it exceeds 97 parts by weight, the coating film will have poor hiding properties.

(11) Inorganic filler Inorganic fillers used in the present invention include heavy calcium carbonate, precipitated calcium carbonate, cold water clay, chalk,
Kaolinic clay, sericite, bentonite, acid clay, precipitated barium sulfate, lithopone, talc, basic magnesium carbonate, barium carbonate, calcium silicate, gypsum, slaked lime, carbon black, diatomaceous earth, colloidal silica, asbestos, graphite , glass fiber, fiber powder, dolomite, zeolite, zinc white, titanium oxide, etc. The amount of these inorganic fillers used is 0 to 7
00 parts by weight, preferably 0 to 600 parts by weight, more preferably 0 to 500 parts by weight. These usage amount is 700
If the amount exceeds 1 part by weight, the film formation as a paint will be insufficient and the physical properties of the paint film will be poor.

Further, in the aqueous coating composition of the present invention, it is preferable to use a hollow polymer pigment having internal pores and titanium oxide together as a masking agent in order to improve the masking property. The preferable ratio is hollow polymer pigment/titanium oxide=1/100~
10010. More preferably hollow polymer pigment/titanium oxide-3/100 to 10015, particularly preferably 5/
It is 100 to 100/10. This allows concealment,
A favorable balance of coating film properties such as weather resistance, water resistance, and alkali resistance can be obtained.

(iii) Others Furthermore, other paint additives can be blended into the composition of the present invention. Other paint additives include:
Calpitol, cellosolve, butyl cellosolve, butyl calpitol, carpitol acetate, cellosolve acetate, butyl cellosolve acetate, butyl carpitol acetate, Texanol C8-12 (Chisso ■
), hexylene glycol, dibutyl glycol phthalate, phthalate esters such as diisopropyl succinate, dibutyl phthalate, and dioctyl phthalate, phthalate esters such as decyl succinate, and aliphatic dibasic acid esters such as decyl succinate. , glycol esters such as ethylene glycol benzoate,
Various plasticizers and film forming aids such as chlorinated paraffins and polyoxyethylene alkyl phenyl ethers; Various surfactants; Inorganic materials such as salts of condensed phosphoric acids such as hexametaphosphoric acid and tripolyphosphoric acid, and salts of polycarboxylic acids. Dispersants for fillers; drying regulators such as mineral turpentine; freeze stabilizers such as glycerin, ethylene glycol, propylene glycol; higher alcohols, polyethers,
Examples include antifoaming agents such as silicone; various thickeners; various preservatives.

This can be added as needed.

In the present invention, a water-based paint composition is prepared by appropriately adding the above-mentioned hollow polymer pigment, pigment binder, inorganic filler, and other additives as necessary.
It is preferred to use a pH adjuster such as sodium hydroxide or ammonia to bring the pH of the formulation to 7 or higher. pH
If it is less than 7, the dispersion stability of the blend will be poor, which is not preferable.

The physical properties of the (hollow) polymer particles described below were measured by the methods shown below.

[(Method for Measuring Physical Properties of Polymer Particles)] (1) Measurement of Particle Size and Internal Pore Size: Measured from electron micrographs using a transmission electron microscope (JEM6'8 100SX manufactured by JEOL Ltd.).

(2) MFT (minimum film forming temperature): Measured using a thermal gradient type film forming temperature measuring device (manufactured by Rigaku Kogyo ■).

(3) Number average molecular weight: (Sample preparation) ■ Treat polymer particles in the form of an aqueous dispersion with an ion exchange resin (Amberlite 1R120 manufactured by Organo ■), and
Adjust to approximately 2.

■ Add 30ml of tetrahydrofuran to 100mg of polymer solid content, leave it at room temperature for 24 hours,
Dissolve the polymer.

■ Pre-filter (AP25- manufactured by Nippon Millipore Industries ■)
1000) and a microfilter (Microfilter FR-100 manufactured by Fuji Film ■) to remove insoluble matter, and the sample was diluted 3 times with tetrahydrofuran and used as a sample.

(Measurement conditions) ■ Measuring equipment: High performance liquid chromatograph HLC-802A manufactured by Toyo Soda ■.

■ Column: Toyo Soda ■ TSK gel G6000S-
G6000S-G5000H8-G4000H8-G4
000H8 (*in no particular order), ■ Fluid solvent: Tetrahydrofuran, ■ Flow rate: 1. The number average molecular weight in terms of polystyrene was measured under the above conditions: 0 ml/min, pressure: 84 kg/cJ.

(4) Measurement of toluene insoluble powder: (procedure) ■ Dry the latex on a glass plate.

■ Pour the dried polymer into a 100m Erlenmeyer flask.
．． Take 15g and weigh it accurately. (Ag)■ Add 50 ml of solvent (toluene) using an autovillet and shake at 60°C for 30 minutes.

■ Toyo Roshi No. 2 (JIS P-38012 type)
The filtrate was filtered using an ultracentrifuge (Hitachi 55P
-2) at 23,000 rpm for 1 hour (*
At this time, the polymer not dissolved in toluene precipitates,
The polymer dissolved in toluene is present in a clear Nanasumi liquid. ).

- Collect 10 ml of IJ using a Holvipet and place it in an aluminum dish (Bg) that has been accurately weighed in advance.

■Hot plate After cooling, accurately weigh the polymer content together with the aluminum plate. (cg) ■ Calculate the solvent-insoluble method from the following formula.

(c-13)
: (Sample Preparation) Polymer particles in the form of an aqueous dispersion were dried and powdered on a glass plate to prepare a sample.

(Measurement condition) It was conducted in accordance with JIS K-721.0.

■ Measuring equipment: Melt Index 1 manufactured by Heavy Industries ■ Temperature: 180°C ■ Load size: 10 kgf [Example] Next, the present invention will be explained in more detail with reference to Examples.
This does not limit the invention. In the following description, "1%" and "part j" represent % by weight and parts by weight.

(1) Production of heterogeneous polymer (S): 80 parts of styrene, 17 parts of methyl methacrylate, 3 parts of methacrylic acid and 7 parts of t-dodecyl mercaptan, 0.5 parts of sodium lauryl sulfate and 1 part of potassium persulfate in 200 parts of water. .0
Pour the solution into an aqueous solution containing 40% of the
Polymer particles were obtained by polymerization for a period of time. This polymer particle has an average particle diameter of 0.2 μm, a number-average molecule calculated by SGPC in terms of polystyrene! It was 6,000. This is designated as S-1.

Production of heterogeneous polymers (S-2 to 7): Polymerization was carried out under the same conditions as S-1 except that the monomer compositions shown in Table 1 were used to obtain heterogeneous polymers S-2 to 7.

Production of heterogeneous polymer (S-8): 2 parts of solid content of heterogeneous polymer S-5 was added to an aqueous solution prepared by dissolving 0.2 parts of sodium lauryl sulfate and 0.7 parts of potassium persulfate in 200 parts of water, and the mixture was stirred while stirring. The temperature was raised to 75°C, and 85 parts of styrene, 7 parts of methyl methacrylate, 8 parts of acrylic acid, and 7 parts of t-dodecyl mercaptan were continuously added for 5 hours to carry out polymerization.
The temperature was raised to °C and aging was carried out for 2 hours. The obtained polymer particles had an average particle diameter of 2 μm and a number average molecular weight of 6,500 in terms of polystyrene by GPC.

This will be referred to as S-8.

In the margin below, the meanings of the abbreviations in Table 1 above and the following tables are as follows.

DVB Divinylbenzene EDMA Edil Non-Glycol Dimethacrylate-1.
ST Styrene AN Acrylonitrile BD Butadiene AA Acrylic acid MAA Methacrylic acid EA Ethyl acrylate BA Butyl acrylate 2EHA 2-ethylhexyl acrylate MMA
Methyl methacrylate 2HEMA 2-hydroxyethyl acrylate methacrylate HH DBS Dodecylbenzenesulfonic acid sthorium PO
ENPE polyethylene nonylphinyl ether (2) Production of pre-hollow polymer particles (P): Using an aqueous dispersion of a different polymer (S-1) as a seed polymer particle,
The solid content of the polymer particles was 1.0 part, 0.1 part of polyoxyethylene nonylphenyl ether, 0.3 part of sodium lauryl sulfate, and 0.3 part of potassium persulfate. 5 parts and 390 parts of water were charged into a reaction vessel. Add to this 75 parts of methyl methacrylate, divinylbenzene (same as pure product equivalent)
Add a mixture of 11.6 parts, 8.4 parts of ethylvinylbenzene, and 5 parts of acrylic acid, and stir at 30°C for 1 hour.17
However, the substance was almost completely absorbed into the seed polymer particles. When this was polymerized at 70° C. for 5 hours with stirring, a dispersion of capsule particles containing water inside the particles was obtained with a polymerization ratio of 99%. When this dispersion was dried and observed under a transmission electron microscope, the polymer particles were completely spherical hollow polymer particles with a transparent center.

This hollow particle has an outer diameter of 0.40 μm and an inner diameter of 0°30 μm.
It was In. This was designated as P-1.

The pre-hollow polymer particles (P) obtained as in 7. were used as seeds in the production of hollow polymer particles (Q) of the present invention described below.

Pre-hollow polymer particles (P-2~6.8.9.1l-11
Production of 3): Using the sample number and usage amount listed in Table 2 as the heterogeneous polymer (S), and using 100 parts by weight of a monomer mixture consisting of the monomer composition (m-1) listed in Table 2. , P2-6.8.9.11.13 was obtained by polymerizing in the same manner as P-1, except that the amount of emulsifier was adjusted. However, P-5 and 6 are different polymers S-
The former was made to absorb 10 parts of toluene and the latter was made to absorb 15 parts of dibutyl phthalate into 12 and 13 parts of No. 2, and then polymerized. The polymerization results are shown in Table 2.

Production of pre-hollow polymer particles (1-7): heterogeneous polymer (
S-8) 2 parts as a solid content, polyvinyl alcohol (Gohsenol GH20, Nippon Gohsei ■
A reaction vessel was charged with 5 parts of 3,5.5-h-lymethylhexanoyl peroxide (Perloil 355, manufactured by NOF Corporation) as a polymerization initiator, and 500 parts of water. To this, 50 parts of 4-vinylpyridine, 1.1 parts of divinylbenzene
parts, 0.8 parts of ethylvinylbenzene, 28 parts of styrene,
A mixture of 20 parts of butyl acrylate and 100 parts of toluene was added and stirred at 40°C for 2 hours to absorb the monomer and solvent into the seed polymer particles, and then heated to 70°C for 1 hour.
Polymerization was performed while stirring for 5 hours, and the polymerization yield was 98%.
A dispersion of capsule particles containing toluene was obtained.

The polymerization results are shown in Table 2.

Production of pre-hollow polymer particles PIO112: Polymerization was carried out in the same manner as P-7 except that the monomer composition and the amount of oily substance toluene used in the production method of P-7 were changed to those shown in Table 1. Plo, 12 was obtained.

Production of blank hollow polymer particles (Q) as follows: Q-1 20 parts solid content of hollow particle aqueous dispersion P-1 prepared by the above method was used as seed particles, 127 parts water, 0 potassium persulfate. .7 parts were placed in a 22-unit reaction vessel, the temperature was raised to 85°C by 1'' under a nitrogen atmosphere, and the following monomer emulsion was continuously added dropwise over 3 hours.

Monomer emulsion: Water 40
1 part Butyl acrylate 5 parts Methyl methacrylate 89 parts Methacrylic acid
After the completion of the dropwise addition of 5 parts, 1 part of N-methylolmethacrylamide, and 0.3 part of sodium dodecylbenzenesulfonate, the temperature was kept at that temperature for 2 hours, and then cooled. There was no coagulum in the resulting dispersion. The particle size of the dispersion was measured with a nanosizer (N-4 model, Coulter Inc.) and was found to be 0.63 μm. This was designated as Q-1. When the obtained dispersion was dried and observed under a transmission electron microscope, it was found that the surface of the pre-hollow polymer particles was coated with a polymer layer. The hollow particles had an outer diameter of 0.63 μm and an inner diameter of 0.30 μm. Further, no new particles were generated, and all particles had hollow spaces. Manufacturing requirements and results are shown in Table 3.

Q-2, 3, 6, Q'-1 to 5 In the production of Q-1, some conditions were changed to Q-2 and Q-2 in Table 3.
Polymerization was carried out in exactly the same manner as Q-1 except that the conditions described in columns 3, 6 and Q'-1 to Q'-5 were changed.

Note that Q' is a manufacturing example outside the scope of the present invention.

In a stainless steel pressure-resistant container at 100°C, 150 parts of water, 1.0 part of potassium persulfate, 0.4 part of sodium hydrogen sulfite, 0.5 part of sodium dodecylbenzenesulfonate, polyoxyethylene nonylphenyl ether (EO = 30 mol) ), and 40 parts of the P-3 as a seed particle in terms of solid content, and while stirring, under a nitrogen atmosphere,
The temperature was raised to 70°C, and the following monomer mixture was continuously added dropwise over 12 hours.

Monomer mixture: 75 parts styrene 1.3-
Butadiene 15 parts methacrylic acid
After addition of 5 parts of Acryester HH and 5 parts of acryester HH, the mixture was aged at 80°C for 5 hours, and then cooled. There was no coagulum in the resulting dispersion. The particle diameter of the dispersion is 0°55 μm, the outer diameter of the polymer particles after drying is 0.54 μm, and the inner diameter is 0.30 μm.
m hollow particles, and no new particles were generated. This was designated as Q-4.

Q-5, 7 and 8 In the production of Q-4, some conditions were changed to Q-5 and Q-5 in Table 3.
Polymerization was carried out in exactly the same manner as Q-4 except that the conditions described in columns 7 and 8 were changed.

Hollow particle aqueous dispersion P-9 was used as seed particles, and the solid content was 500 parts, water 1400 parts, sodium dodecylbenzenesulfonate 0.7 part, polyoxyethylene nonylphenyl ether (EO = 30 mol) 0. One portion was placed in a 2C reaction vessel. To this, 5 parts of n-butyl acrylate,
A mixture of 89 parts of methyl methacrylate and 6 parts of methacrylic acid was added and stirred at 40° C. for 1 hour, so that the monomer mixture described in “1” was almost completely absorbed into the seed hollow polymer particles.

To this were added 1.0 part of benzoyl peroxide and 0.5 part of sodium bisulfite, the temperature was raised to 70°C, polymerization was carried out for 5 hours, and then cooled. There was no coagulum in the obtained dispersion, and the outer diameter of the polymer particles after drying was 0.4 μm.
The particles were hollow particles with an inner diameter of 0.30 μm, and no new particles were generated. This was designated as Q-9.

Q'-6 and 7 The following ordinary polymer particle dispersion was used instead of the pre-hollow polymer particle (P) dispersion of Q-1, and the particle size of the obtained polymer particles was 0. The diameter was 64 μm and there were no inner holes. Let this be Q'6.

Seed polymer particle dispersion P'-1° Aqueous dispersion produced by conventional emulsion polymerization. Particle size 0.40 μm 5 pH 7
, 2, solid content 40%, composition is butyl acrylate/methyl methacrylate/styrene/acrylic acid = 45/10/
42/3 and no internal holes.

Q'7 was obtained by changing the type and amount of the seed polymer particles used in the above method to those shown in Table 3 and below.

Seed polymer particle dispersion P'-2° Aqueous dispersion produced by conventional suspension polymerization. Particle size 4 μm, pH 7.8,
Solid content 45%. The composition is ethyl acrylate/styrene/
Acrylic acid = 20/79/1, no internal pores.

Commercially available polymer fine particles (manufactured by Rohm & Hass)
p84) was designated as P'-3, and plastic pigment AK8801 manufactured by Asahi Kasei Corporation was designated as P'-4.

Q'-8 Hollow particle aqueous dispersion P'-3 is used as seed particles,
200 parts solids, 460 parts water, 0.5 potassium persulfate
A total of
The temperature was raised to 1'' and the following monomer emulsion was continuously added dropwise over 3 hours to polymerize.

Monomer emulsion; water 40
95 parts styrene 5 parts methyl methacrylate 0.3 parts sodium dodecylbenzenesulfonate 0.1 part polyoxyethylene nonylphenyl ether After the dropwise addition was completed, the temperature was maintained for 2 hours and then cooled. The outer diameter of the polymer particles after drying is 0.62 μm and the inner diameter is 0.3
The particles were hollow particles with a diameter of 0 μm, and no new particles were generated.

The monomer composition of the different polymer (S), the monomer composition (m-1) of the pre-hollow polymer particles (P), the monomer composition (m-2) of the hollow polymer particles (Q), and (m-2) 10
From the amount of pre-hollow polymer particles (P) and heterogeneous polymer (S) used relative to 0 parts, the polymerized units (a), (b), (c), (d) defined in the claims % was calculated and listed in Table 3. Further, the physical properties of each particle are listed in Table 4.

Margin Examples 1 to 9 and Comparative Examples 1 to 13 As shown in Table 5, a white pigment was used to obtain a coating liquid for gravure printing (solid content: 62%) having a composition shown in Table 6.

Table 5 Table 6 Using 100 parts of clay The coating liquids obtained in Examples 1 to 9 and Comparative Examples 1 to 13 of 2 are applied to one side of medium-quality base paper, immediately placed in a hot air dryer, and heated to 150° Dry for 30 seconds at 50°C, then dry at 50°C.
After supercalendering twice under the condition of 100 kg/cd, it was left in a constant temperature room (20°C, 165% RH). Table 7 shows the physical properties of the coated paper thus obtained.

The following methods were used to measure each physical property of the coated paper.

(1) Dry pick: Using R■ and a printing machine, overprint several times with ink of tack No. 8, and visually judge the picking condition of the printed surface and evaluate it using a 5-point method.

The larger the number, the better.

(2) Wet pick: Using a Morton roll with an RI printing machine, the picking state of the printed surface when printing is applied with dampening water is visually judged and evaluated using a 5-point method. The larger the number, the better.

(3) White paper gloss: Measured using a Murakami gloss meter (75°-75°). The larger the number, the better.

(4) Printing gloss: Use an RI printing machine to print the web offset ink, and use the Murakami gloss meter (75°-75
Measured using °).

(5) Whiteness: Measured using a Hunter colorimeter (using a blue filter).

(6) Opacity: Measured by Hunter colorimeter (using green filter).

(7) Gravure printing aptitude: Using a gravure printing aptitude tester (Ministry of Finance Printing Bureau type), the appearance of speckles on the printed test piece is visually judged and graded. The evaluation is shown in the following four stages.

◎: Best, ○: Good, △: Fair, ×: Bad Table 7 (Physical properties of coated paper) Table 7 (Continued) Examples 10 to 15, Comparative Examples 14 to 18 Offset of the composition shown in Table 8 Printing coating liquid (solid content 6
4%).

Comparative Examples 19 and 20 Comparative Examples 1 and 20 were prepared in exactly the same manner as in Example 11, except that 12 parts of the pigment binder (latex) in Example 11 was changed to 2 parts and 40 parts, respectively.

These coating solutions were applied to one side of base paper, immediately dried at 150℃ for 30 seconds, and then heated at 50℃ for 100k.
After supercalendering twice under g/c♂ conditions, it was left in a constant temperature room (20° C., 65% RH). Table 9 shows the physical properties of the coated paper thus obtained. Note that the methods for measuring each physical property are the same as those in (1) to (6) above. Moreover, the trapping property was measured by the method shown below.

(7) Trapping property: Using an R1 printing machine manufactured by Mei Seisakusho, the printed surface was visually judged and graded.

The evaluation is shown in the following four stages.

◎: Best, ○: Good, △: Fair, ×: Poor or below Margin pigment binder, carboquine-modified styrene-butanene copolymer latex (manufactured by Japan Synthetic Rubber Co., Ltd. #0619) No. 9
Table (Physical properties of coated paper) From the above test results, the following was found.

In Comparative Example 1, the inner diameter/outer diameter ratio of the hollow polymer particles was smaller than 0.2, and the whiteness and opacity were significantly inferior.
Undesirable.

Comparative Example 2.5 is a case where the particle diameter of the hollow polymer particles exceeds 20 μm, which is not preferable because the polymerization stability is poor, new particles are generated, and the gloss and strength (dry pick, wet pick) are poor.

Comparative Example 3 has a particle diameter of less than 0.15 μm, poor polymerization stability, and generation of new particles, resulting in significantly poor opacity, whiteness, and gloss.

Comparative Example 4 has over 90% of toluene insolubility and MFR
is less than 0.1, and the inner diameter/outer diameter ratio exceeds 0.8, resulting in significantly inferior gloss and strength of the coated paper.

Comparative Example 11 uses hollow polymer particles as a white pigment, but the surface is not modified with another preferable polymer layer, and although the whiteness and opacity are satisfactory in this example, the coating is Poor paper strength (dry pick, wet pick), gloss and printability.

Comparative Examples 8 to 10 and Comparative Example 16 use solid polymer particles as white pigments, and although these examples have some gloss, coated paper strength, whiteness, opacity, and printability are inferior. .

Comparative Examples 12 and 17 use titanium oxide as a white pigment, and these examples have excellent whiteness and opacity, but are inferior in coated paper strength, gloss, and printability.

Comparative Example 13 does not use a white pigment, and although the coated paper strength is satisfactory, the gloss, whiteness, opacity, and printability are poor.

Comparative Example 14 used hollow polymer particles for white pigment in an amount of less than 1 part by weight, and although the coated paper strength was satisfactory, the gloss, whiteness, opacity, and printability were poor.

In Comparative Example 15, the amount of hollow polymer particles for white pigment used exceeds 50 parts by weight, and although the whiteness and opacity are excellent, the coated paper strength, gloss, and printability are poor.

Comparative Example 19 is an example in which the amount of pigment binder used is less than 3 parts by weight based on 100 parts by weight of pigment, and although whiteness and opacity are satisfactory, coated paper strength, gloss, and printability are poor.

Comparative Example 20 is an example in which the amount of pigment binder used exceeds 30 parts by weight per 100 parts by weight of pigment, and it is difficult to uniformly apply it to coated paper because of the high viscosity of the coating liquid. Therefore, it was not possible to create coated paper.

Comparative Example 6.7 and Comparative Example 18 are (rV
) Manufactured by the alkali swelling method, the particle surface is designed to have good binding properties with pigments and pigment binders and dispersion stability during compounding, making it difficult to modify and maintaining internal pores. polymer layer (styrene-acrylic)
Because of its low Tg, it has the disadvantage of low resistance to heat and pressure treatments such as calendering,
Although the whiteness and opacity are somewhat low, the coated paper strength (
dry pick, wet pick) and gravure printing suitability,
This results in a coated paper with poor trapping properties.

Example 16 A water-based coating composition was obtained using the hollow polymer particles (pigment) Q-1 as a white pigment and having the formulation shown in Table 10.

Table 10 Table 10 (continued) *1 Japanese synthetic rubber; AE316, toluene insoluble 5
0%, Tg5°cSMFT1.5°C*2 Amount at which the concentration of components other than water in the entire composition is 55% by weight*3 (NV) v%...Non-volatile volume fraction white LJJi? 4 volume + voluminous resin volume (dry) (NV
) v -Kari00 Total volume of coating El (wet) *4 PvC... Pigment volume fraction white N
1 [Volume (dry) Examples 17 to 22 The white pigments in Table 10 were Q-2, Q-3, Q-6,
A coating composition with a nonvolatile volume fraction (NV) v = 4)% and a pigment volume fraction PVC = 20%, with the same formulation as in Example 16 except that Q-7, Q-8, and Q-9 were changed. I got it.

Comparative Example 21 The white pigment in Table 10 was added to pre-hollow polymer particles P-1.
, the amount used was changed to 23.4 parts (solid content), and the amount of water added was adjusted in the same manner as in Example 16 (
A coating composition with NV)v = 4)% and PVC-20% was obtained.

Comparative Example 22.23 Each of the white pigments in Table 10 was mixed with polymer particles Q'
-6 and commercially available polystyrene latex L-8801 (
(manufactured by Asahi Kasei Industries ■), the amount used was changed to 32 parts (solid content), and the amount of water added was adjusted in the same manner as in Example 16 (NV)v = 4)%, PVC = 20
% of the paint composition was obtained.

Comparative Example 24 The white pigment in Table 10 was changed to titanium oxide (R, -930 manufactured by Ishikata Sangyo), the amount used was changed to 124°7 parts (solid content), and the amount of water added was adjusted. With the same formulation as Example 16, (NV)v = 4)%, PVC = 20%
A coating composition was obtained.

Comparative Examples 25 to 29 The white pigments in Table 10 were used as Q'-1, Q'2, Q'-
3, non-volatile volume fraction (NV) v = 4)%, using the same formulation as in Example 16 except that Q'-4 and Q'-8 were changed.
A coating composition having a pigment volume fraction of PVC=20% was obtained.

Each of the aqueous coating compositions of Examples 16 to 22 and Comparative Examples 21 to 29 described above was applied to a substrate so that the film thickness was constant, and was dried to form a film. Table 11 shows the physicochemical properties of each coating film.

Note that the following methods were used to measure each physical property of the coating film.

$3) 60° mirror gloss (glass plate): Paint is applied to a glass plate using a 3 mil applicator, and the temperature is 25°C%.
652° drying in RH for 10 minutes.Noshinimura'1 gloss; measured at 1.

*4) 45% gloss (hiding rate test paper): Apply the paint to the hiding rate test paper using a 6 mil applicator, and
After drying in C165%RH for 10 minutes, the angle of incidence was 45°.
, was measured using a Murakami gloss meter with a reflection angle of 0°.

*5) Light transmittance of coating film: Using the coating film of *3), the incident r(
It was measured with a Murakami gloss meter at +90° and a reflection angle of 0°.

*6) Hiding rate: Using the coating film of *4), the gloss of the white background area and the black background area at 45° and 10° was measured, and the ratio thereof was calculated using the following formula.

Black ground 1- rI + crotch 45° / (1" expansion 1'dl
Hf*7) Water Resistance 2*3) Glass plate coating film was immersed in distilled water at 25°C for 7 days and judged visually.

(judgement) ◎: No blistering or blistering of the coating film.

○: No blistering of the coating film, some blistering.

△: There is some blistering and blistering in the coating film.

×: Large blistering of the coating film and excessive blistering.

*8) After water resistance and light transmittance 2 *7) After the test, the gloss of the coating film was measured using a Murakami gloss meter (60°/60°), and calculated as the ratio to the gloss of *3).

*9) Light transmittance after water resistance: After the test in *7), the gloss of the coating film was measured using a Murakami gloss meter (90° 10°), and calculated as the ratio to the light transmittance in *5).

*10) Alkali resistance 2*3) glass plate coating with 2%N
aOH, immersed in saturated Ca(OH)2 solution for 7 days,
Judging visually.

(judgement) O: Blistering of coating film, no blistering.

△: There is some blistering and blistering in the coating film.

×: Large blistering of the coating film and a lot of blistering.

*11) Gloss retention after alkali resistance: After the *lO) test, the coating was dried for one day at 25°C and 65% RH, and the gloss was measured using a Murakami gloss meter (60°/60°). , *3) Calculated as a ratio to gloss.

*12) Alkali resistance after light transmittance: After the $10) test, the coating film was dried for one day at 25°C and 65% RH, and the gloss was measured using a Murakami gloss meter (90° 10°). *5) Calculated as a ratio to light transmittance.

*13) Heat resistance 2 *10
Place it in a thermostat kept at 0°C and leave it for a day, then put it indoors.
Wait a while and visually judge.

(judgement) ○: No blistering or blistering of the coating film.

△: No blistering of the coating film, with blistering.

×: There is blistering and blistering in the coating film.

*14) Hiding rate after heat resistance 2 The coating on the hiding rate test paper prepared in *4) was placed in a thermostat kept at 100℃ for 1 day, then placed indoors for 3 hours, and the 45° and 10° gloss was determined by Murakami gloss. It was calculated using the formula *6).

*15) Washing resistance: Paint was applied to a PVC sheet using a 6 mil applicator, dried for 3 days at 25°, 0165% RH, washed with a Gardner wash resistance tester, and judged visually.

(judgement) ○: No peeling of the coating after 2000 times or more.

△: The coating film peeled off after 1000 to 2000 cycles.

X: The coating film peeled off after being used less than 1000 times.

*16) Impact resistance: 5S4) The coating film was applied to a steel plate using a 100 μm applicator and dried at 25°C and 65% RH for 48 hours, and then fixed on a steel column stand, with a diameter of 25.
After a 4 mm steel ball is dropped from a height of 1 m, the state of the coating film is visually determined.

(judgement) ○: The coating film does not crack or peel off.

Δ: There is some cracking or peeling of the coating film.

×: Significant cracking and peeling of the coating film.

*17) Weather resistance: After coating the paint on a slate board and drying it for 10 days, the condition of the paint film was visually judged after being exposed for 6 months.

(Judgment) ○: Good △: Average Visually judge the condition of the paint film after irradiation for one day.

(Judgment) 0: Good △: Average ×: Poor *19) Solvent resistance; After drying the glass plate coating film prepared in *3) for 1 day, it was immersed in toluene at room temperature for 24 hours, and visually judged.

(judgement) ○: No blistering or blistering of the coating film.

△: There is some blistering and blistering in the coating film.

×: Large blistering of the coating film and a lot of blistering.

*20) Adhesion (adhesion): Apply the prepared paint to the flexible board twice with a brush (200g/at),
After drying for 5 days, use a razor to make 2mm square squares.
Perform a peel test with cellophane tape and visually judge (
JIS A, -6910).

(Judgment) ○: Good △: Average ×: Poor *21) Film strength: A 0.5 mm coating film dried for 5 days was punched out with a No. 2 dumbbell and evaluated using an autograph (20° C., 60% RH).

Examples 23 to 29 The amount of white pigment polymer particles used in the formulation in Table 10 of Example 16 was changed, and Q-3 was used as the polymer particles.
PVC-30%, (
A coating composition with NV)v =37% was obtained.

Comparative Examples 30 to 32 OP-62 (Rohm
& llaas styrene-acrylic hollow resin latex particle size 0.4 μm 1 inner pore size 0.27 μm) and 5
pindrift (IcI DULUX polyester (Ti02, containing micropores) polymer dispersion,
A coating composition with PVC = 30% and (NV)v = 37% was created by using a particle size of 5 μm), changing the usage amount from Table 10, and using titanium oxide R, -930 in some cases. Obtained.

Comparative Example 33 A coating composition with pvc=o% and (NV)v-37% was obtained by not using a white pigment and by changing the amount of water used in Table 10.

Comparative Example 34 Using the same formulation as in Table 10 except using only titanium oxide as a white pigment and changing the amount of water used, (NV)v
A coating formulation with PVC=37% and PVC=15% was obtained.

The coating compositions obtained in Examples 23 to 29 and Comparative Examples 30 to 34 above were applied to a substrate so that the film thickness was constant,
A film was formed by drying. Table 12 shows the physicochemical properties of each coating film.

*22) (PVC) pp・・・・・・PVC of polymer particles for white pigment Volume (dry) of polymer particles for white pigment 00*23
) (PV C) T102... PVC of titanium oxide Volume of titanium oxide (drill r) 0 cut or less, margin or more Test results revealed the following.

Comparative Example 21 is an example in which the surface of the pre-hollow polymer particles (P) having small pores according to the present invention was used as a white pigment without coating the surface with a polymerizable monomer. As a result, although it has hiding properties, it has poor adhesion to the binder resin in the coating composition, and has poor water resistance, alkali resistance, weather resistance, wash resistance, impact resistance, adhesion, and film strength.

Comparative Example 22 is an example in which polymer particles without internal pores are used as a white pigment, and has no hiding properties and low adhesion to the binder resin, and all physical property values in Table 11 are It was inferior.

Comparative Example 23 uses commercially available polystyrene particles L-8801 (
This is an example using Asahi Kasei Kogyo Co., Ltd.), and although it had gloss, the coating film had poor hiding properties and other resistance.

In Comparative Example 25, the inner diameter/outer diameter ratio of the hollow polymer particles was 0.2.
It is smaller and less concealable, making it undesirable.

Comparative Example 26 is a case where the particle size of the hollow polymer particles exceeds 20 μm, and the polymerization stability is poor, new particles are generated,
The coating film had some hiding power, but had low gloss and was otherwise poor in resistance.

In Comparative Example 27, the particle diameter was less than 0.15 μm, the polymerization stability was poor, the generation of new particles was observed, and the resistance of the coating film was extremely poor.

In Comparative Example 28, the toluene insoluble portion of the hollow polymer particles was 9.
0%, MFR is less than 0.1, inner diameter/outer diameter ratio is more than 0.8, and the gloss, resistance, and strength of the coating film are poor.

Comparative Example 29 is a hollow polymer particle consisting of two non-crosslinked layers, both the inner layer and the outer layer, and although it has hiding properties and gloss, it is inferior in other durability.

Comparative Example 24.34 uses titanium oxide (R-
This is an example using only 930), and although it has excellent hiding properties, it is inferior in gloss, alkali resistance, heat resistance, and film strength.

Comparative Example 30 is 0 P manufactured using conventional technology (rV).
-62 (Rohm & Haas) was used as a white pigment, and in Comparative Example 31, titanium oxide was also used. The polymer particles having small pores inside produced by this production method (IV) had hiding properties and gloss, but were poor in other properties such as resistance.

Comparative Example 32 is a polyester polymer particle having an outer diameter of 5 to 10 μm and containing a large number of micropores and titanium oxide particles inside, manufactured by the conventional technique (VI). When these particles were used, the coating film had excellent hiding properties, but had extremely low gloss and poor other resistance.

Comparative Example 33 is an example in which no white pigment was used, and the coating film was nearly transparent and had no hiding properties.

Comparative Example 35 is an example in which hollow polymer particles were used in an amount of 3 parts by weight or less out of a total of 100 parts by weight of hollow polymer particles and film-forming binder, and a sufficient hiding rate could not be obtained.

Comparative Example 36 is an example in which 95 parts by weight or more of hollow polymer particles are used out of a total of 100 parts by weight of hollow polymer particles and film-forming binder, and Comparative Example 37 is an example in which hollow polymer particles and film-forming binder are used in an amount of 95 parts by weight or more. This is an example in which 700 parts or more of the inorganic filler (Ti02) was used for a total of 100 parts by weight of the binder, and in both cases, the film forming properties were very poor, and although it had hiding properties, other physical properties of the coating film were poor. became inferior.

[Effects of the Invention] (a) The hollow polymer pigment of the present invention is a novel, industrially useful material that has highly crosslinked strong inner pores and a polymer composition with a favorable particle surface. whiteness, light weight, adhesion, concealability, moderate heat resistance,
It has excellent safety and solvent resistance, and can be handled as dried hollow particles or as an aqueous dispersion stably dispersed in water. It can be used as a pigment for various paints and cosmetics, and by sealing drugs into the inner pores, it can be used as a drug-releasing material, anti-mold paint, anti-corrosion paint, as well as heat insulating materials and anti-condensation paints using the air in the inner pores. It can also be used for

(b) The paper coating composition containing the hollow polymer pigment of the present invention has excellent whiteness, opacity, coated paper strength, gloss, and printability that were not possible with conventional paper coating compositions. It became possible to achieve a well-balanced improvement without compromising the quality of the product.

The paper coating composition of the present invention can produce coated paper that has good coating workability and drying properties, is lightweight, and has gloss; excellent whiteness, opacity, and printability such as gravure and offset. .

(c) A general-purpose coating composition containing the hollow polymer pigment of the present invention provides a coating film with excellent hiding properties, gloss, water resistance, alkali resistance, heat resistance, etc., and is also excellent in handling and stability. Provided is a general-purpose coating composition that also functions as a lightweight coating film.

In particular, when used as a pigment in a water-based paint, the resulting water-based paint composition has excellent miscibility and adhesion with other formulations.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Scope of Claims] 1. A hollow polymer pigment consisting of hollow polymer particles having at least two polymer layers, wherein the hollow polymer particles (1) have an average particle diameter of 0.15 to 20 μm; (2) the average ratio of equivalent hollow diameter to equivalent particle size for each particle is in the range of 0.2 to 0.8, and (3) the proportion of toluene-insoluble portion is in the range of 20 to 90% by weight. (4) The melt flow rate under the conditions of 180°C and 10 kgf/cm^2 is 0.1 to 1 g/10 min, (5) The inner layer of the above two polymer layers has the following formula (a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(a) (Here, R^1 is a hydrogen atom or a methyl group, and
is an n-functional organic group or a bond, and n is a number of 2 or 3, provided that n R^1s may be the same or different, and when X is a bond is n
is 2. ) The polymerized unit represented by the following formula (b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(b) (Here, R^2 is a hydrogen atom or a methyl group, and Y is a phenyl group. or a phenyl group substituted with a halogen atom, an alkyl group or a vinyl group, a halogen atom, a cyano group, an alkanoyloxy group having 1 to 18 carbon atoms, an alkoxy group, pyridyl, pyridylalkyl, aminoalkoxy or amide The polymerized unit represented by the following formula (c) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(c) (Here, R^3 and R^5 are the same or different,
A hydrogen atom or a methyl group, R^4 is a hydrogen atom, a carboxyl group or a carboxylate group, and R^6
is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, and a hydrogen atom having 2 to 18 carbon atoms.
10 hydroxyalkyl groups or an organic group having at least one member selected from glycidyl, amino, cyano and carbon-carbon double bonds, or one equivalent of a base. ), and in some cases, the following formula (d
) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(d) A polymerized unit represented by (where R^7 is a hydrogen atom or a methyl group), consisting of a crosslinked polymer consisting of, and (6) The outer layer of the two-layer polymer has the above formulas (b) and (c
A hollow polymer pigment comprising a non-crosslinked polymer comprising at least one polymer unit selected from the group consisting of (a) and (d). 2. 100 parts by weight of a pigment consisting of 1 to 50% by weight of the hollow polymer pigment according to claim 1, 50 to 99% by weight of a mineral inorganic pigment, and 0 to 25% by weight of a non-hollow polymer pigment, and 3 to 3 parts by weight of a pigment binder. A paper coating composition containing 30 parts by weight. 3. A general-purpose coating composition comprising 3 to 95 parts by weight of the hollow polymer pigment according to claim 1 and 5 to 97 parts by weight of a pigment binder, a total of 100 parts by weight, and 700 parts by weight or less of an inorganic filler.