JP2001151806A - Acrylic emulsion for sliding prevention, method for producing the acrylic emulsion and coating composition for sliding prevention - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic emulsion for sliding prevention having excellent anti-slip properties and blocking resistance, not requiring the use of an organic solvent. SOLUTION: This acrylic emulsion for sliding prevention is an emulsion of an acrylic (co)polymer of double structure composed of a nuclear part having 670 nm average particle diameter and a shell part, dispersed and stabilized with an alkali-soluble copolymer neutralized substance in which the glass transition temperature (Tg) of the (co)polymer of the nuclear part is 67 deg.C, the (co)polymer of the shell part has 12 wt.% of an acrylonitrile monomer unit and 88 wt.% of ethyl acrylate and has -12 deg.C Tg, the weight ratio of the (co)polymer of the nuclear part to the alkali-soluble copolymer is 77/23 and the ratio of the total weight of the (co)polymer of the nuclear part and the copolymer constituting a polymer protective colloid to the weight of the (co)polymer of the shell part is 40/60. This coating composition comprises the acrylic emulsion and a filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-slip acrylic emulsion, and more particularly, to a non-slip acrylic emulsion having excellent anti-slip properties and anti-blocking properties which is applied to the surface of cardboard, paperboard and the like to give them anti-slip effects. The present invention also relates to a method for producing the composition and a non-slip coating composition comprising the anti-slip acrylic emulsion and a filler.

[0002]

2. Description of the Related Art Many products, such as agricultural products, marine products, processed foods, and various industrial products, are packed in paper containers such as cardboard boxes and cartons and various paper bags, stacked on pallets, and transported. If these packaged products slip during loading or transportation, they collapse, causing not only a reduction in transportation efficiency, but also a problem of damaging the products and putting the human body at risk.

[0003] In order to prevent this collapse, these paper containers,
BACKGROUND ART In order to impart anti-slip properties to the surface of a paper bag, application of an anti-slip agent has been conventionally performed. Such anti-slip agents include a non-adhesive anti-slip agent and an adhesive anti-slip agent.

[0004] As a non-stick type anti-slip agent, a coating composition combining an inorganic filler and a binder (copolymer emulsion) is applied to form an uneven film on the surface of a paper container or the like. There is a method of preventing slippage by engaging a target (for example, Japanese Patent Application Laid-Open No. 55-10759).
7, JP-A-61-186597), when the amount of the inorganic filler is small, the paper coated with the coating composition adheres to another paper (hereinafter referred to as blocking), and when peeled, the paper breaks, However, there is a problem that when the amount is too large, the transparency of the coating layer is impaired. As a method for improving transparency, it has been proposed to use a composite particle emulsion composed of colorless and transparent colloidal silica and an acrylic copolymer (JP-A-1-308748). However, there is a problem that the emulsion is agglomerated at the time of coating because of lack of water.

As an adhesive type anti-slip agent, a double-structured acrylic emulsion in which the core has a glass transition temperature (hereinafter referred to as Tg) of 20 to 90 ° C. and the shell has a Tg of -20 to 10 ° C. (Japanese Patent Laid-Open No. 4-30)
6273) has been proposed, but there is a problem that blocking occurs when the temperature rises. Also, a method of preventing slippage by a composition containing a terpene (co) polymer in a vinyl polymer emulsion (Japanese Patent Laid-Open No. 6-80)
953) has been proposed, but there is a problem in that an organic solvent is contained in dissolving the terpene (co) polymer, so that it is necessary to consider the effects on fire and the human body.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an acrylic emulsion for anti-skid which has excellent anti-slip properties and anti-blocking properties and does not require the use of an organic solvent.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that a specific range of average particles dispersed and stabilized with a neutralized alkali-soluble copolymer is obtained. It has been found that the above object can be achieved by using an acrylic emulsion having a double structure having a diameter, and the present invention has been completed based on this finding.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Thus, according to the present invention, a dispersion-stabilized 300% neutralized alkali-soluble copolymer is obtained.
An emulsion of a double-structured acrylic (co) polymer having a core part and a shell part, having an average particle diameter of ~ 1000 nm, wherein the core part (co) polymer has a glass transition temperature (Tg) of 30 to 110 [deg.] C., and the (co) polymer of the shell portion contains 2 to 15% by weight of ethylenically unsaturated nitrile monomer units and 85 to 98% by weight of other ethylenically unsaturated monomer units copolymerizable therewith. Having a Tg of -5
0 to + 20 ° C., and the weight ratio between the core (co) polymer and the alkali-soluble copolymer is 40/60 to 85 /
15, and the ratio of the total weight of the core (co) polymer and the alkali-soluble copolymer to the weight of the shell (co) polymer is 20/80 to 50/50. An acrylic emulsion is provided.

Further, according to the present invention, a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and other ethylenically unsaturated monomers copolymerizable therewith in the presence of a (co) polymer emulsion of a core portion. An emulsion obtained by polymerizing a monomer composed of a monomer. A method for producing an acrylic emulsion for anti-slip is provided, which comprises adjusting the pH to 7 or more, and then further adding and polymerizing a monomer for constituting a (co) polymer of a shell portion.

Further, according to the present invention, in polymerizing a monomer for constituting the (co) polymer of the shell portion, a monomer for constituting the (co) polymer of the shell portion is prepared. , A polymerizable emulsifier, a neutralized product of a copolymer obtained by polymerizing a monomer comprising an ethylenically unsaturated carboxylic acid monomer and other ethylenically unsaturated monomers copolymerizable therewith. Emulsifying in the presence of the core (co) polymer emulsion,
A method for producing an acrylic emulsion for anti-slip which is characterized by being polymerized is provided.

Further, according to the present invention, there is provided an anti-slip coating composition comprising the anti-slip acrylic emulsion and a filler.

Hereinafter, the present invention will be described in detail. In the present invention, the acrylic emulsion is defined as an ethylenically unsaturated carboxylic acid ester monomer unit and an ethylenically unsaturated carboxylic acid monomer unit among all (co) polymer monomer units constituting the emulsion. Is 50% by weight
The above is an emulsion.

The acrylic emulsion for anti-slip of the present invention comprises:
Acrylic with double structure consisting of core and shell (co)
It is an emulsion of a polymer. In the present invention, an emulsion having a double structure is one in which particles have a different layer structure.
An emulsion in which the particle surface of the (co) polymer having a high g portion in the core is completely or partially covered with the (co) polymer having a shell portion having a low Tg.

(Core (co) polymer) Core (co) polymer
The polymer has a Tg of 30 to 110 ° C, preferably 50 to 110 ° C.
It needs to be 100 ° C. If the temperature is lower than 30 ° C., the blocking resistance of the coating layer deteriorates,
If it is higher, the slip resistance becomes poor.

The monomer for producing the core (co) polymer is not particularly restricted but includes, for example, aromatic vinyl monomers, ethylenically unsaturated carboxylic acid ester monomers, ethylenically unsaturated monomers. Carboxylic acid monomers, ethylenically unsaturated carboxylic acid amide monomers, ethylenically unsaturated nitrile monomers, crosslinkable monomers and the like can be used. These monomers may be used alone or in combination of two or more.

The aromatic vinyl monomer is not particularly restricted but includes, for example, styrene, methylstyrene, vinyltoluene, chlorostyrene, hydroxymethylstyrene and the like. Of these aromatic vinyl monomers, styrene is preferred.

The ethylenically unsaturated carboxylic acid ester monomer is an ester of ethylenically unsaturated monocarboxylic acid or ethylenically unsaturated polycarboxylic acid with various alcohols which may have a substituent such as halogen. It is. Examples of the ethylenically unsaturated monocarboxylic acid ester monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid- 2-ethylhexyl, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate,
(Meth) acrylates such as cyanomethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and glycidyl (meth) acrylate; ethylenically unsaturated polycarboxylic acid esters Examples thereof include dibutyl maleate, dibutyl fumarate, diethyl maleate and the like.

Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; and ethylene such as fumaric acid, maleic acid, itaconic acid and butenetricarboxylic acid. Unsaturated polycarboxylic acids; monoethyl maleate;
Examples include partial esters of ethylenically unsaturated polycarboxylic acids such as monomethyl itaconate.

Examples of the ethylenically unsaturated carboxylic acid amide monomer include (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, and N-methoxymethyl (meth).
(Meth) acrylamide monomers such as acrylamide.

Examples of the ethylenically unsaturated nitrile monomer include (meth) acrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile and the like.

Examples of the crosslinkable monomer include conjugated divinyl compounds such as divinylbenzene; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) A) acrylate and other poly (meth) acrylate compounds.

(Copolymer of shell part) (Co) of shell part
The polymer has a Tg of -50 to + 20C, preferably -2.
It is necessary to be 5 to + 5 ° C. If the temperature is lower than -50 ° C, the blocking resistance decreases, and if it is higher than + 20 ° C, the slip resistance decreases.

The composition of the (co) polymer of the shell part is 2 to 15% by weight of ethylenically unsaturated nitrile monomer units and 9% of other ethylenically unsaturated monomer units copolymerizable therewith.
8 to 85% by weight.

Examples of the ethylenically unsaturated nitrile monomer include (meth) acrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile and the like which can be used in the core (co) polymer. These can be used alone or in combination of two or more. Of these, acrylonitrile is preferred. If the amount of the ethylenically unsaturated nitrile monomer unit is less than 2% by weight, the blocking resistance is deteriorated. If the amount is more than 15% by weight, the coating layer is colored by heating.

The other ethylenically unsaturated monomers copolymerizable with the ethylenically unsaturated nitrile monomer are not particularly limited, and include aromatic vinyl monomers and ethylenically unsaturated monomers that can be used in the nucleus. Saturated carboxylic acid ester monomers, ethylenically unsaturated carboxylic acid monomers, ethylenically unsaturated carboxylic acid amide monomers and the like can be used. Of these, ethylenically unsaturated carboxylic acid ester monomers are preferred,
Among them, ethyl acrylate is preferred.

(Neutralized Alkali-Soluble Copolymer) It is essential that the acrylic emulsion for anti-slip of the present invention is dispersion-stabilized with a specific neutralized alkali-soluble copolymer. The alkali-soluble copolymer neutralized product used in the present invention is obtained by copolymerizing a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and another ethylenically unsaturated monomer copolymerizable therewith. Is a neutralized product of an alkali-soluble copolymer. As a method of dispersion stabilization, the monomers constituting the alkali-soluble copolymer and the polymerizable emulsifier are polymerized and neutralized in the presence of the (co) polymer emulsion of the core portion, and the shell portion is neutralized. A method for polymerizing the constituting monomers, a monomer for constituting the (co) polymer of the shell portion is emulsified by using a neutralized product of an alkali-soluble copolymer, and the emulsified product is subjected to In the presence of a (co) polymer emulsion,
The method of adding and polymerizing is mentioned.

The alkali-soluble copolymer is prepared by using a polymerizable emulsifier to form an ethylenically unsaturated carboxylic acid monomer 15 to 5;
It is obtained by copolymerizing 5% by weight, preferably 20 to 40% by weight, and 45 to 85% by weight, preferably 60 to 80% by weight of another ethylenically unsaturated monomer copolymerizable therewith.

The alkali-soluble copolymer has a molecular weight of 500 to 20,000, preferably 1,000 to 15,
000. If the molecular weight is smaller than 500, the alkali-soluble copolymer is less likely to be adsorbed on the particle surface, so that the dispersion stabilizing effect is reduced. If the molecular weight is larger than 20,000, the viscosity becomes high and handling becomes difficult.

The polymerizable emulsifier which can be used for the alkali-soluble copolymer is a surfactant having at least one polymerizable carbon-carbon unsaturated bond in the molecule. Anionic polymerizable emulsifiers such as sodium ethylhexylbenzenesulfosuccinate, sulfate of polyoxyethylene (meth) acrylate, ammonium sulfate of polyoxyethylene alkylpropenyl ether sulfate, and phosphate of polyoxyethylene (meth) acrylate; polyoxyethylene Nonionic polymerizable emulsifiers such as alkyl benzene ether (meth) acrylate and polyoxyethylene alkyl ether (meth) acrylate are exemplified. The amount of the polymerizable emulsifier used is usually based on 100 parts by weight of the monomer for constituting the alkali-soluble copolymer.
It is 0.1 to 2.0% by weight, preferably 0.2 to 1.0% by weight.

The ethylenically unsaturated carboxylic acid monomer for constituting the alkali-soluble copolymer is not particularly limited, and those similar to the (co) polymer in the core or shell can be used. . When the amount of the ethylenically unsaturated carboxylic acid monomer is less than 15% by weight, the obtained coated paper has poor blocking resistance, and when the amount is more than 55% by weight, the viscosity of the emulsion becomes high and handling becomes difficult.

The polymerizable emulsifier and other ethylenically unsaturated monomers copolymerizable with the ethylenically unsaturated carboxylic acid monomer are not particularly limited, and may be used in the (co) polymer of the core or shell. Aromatic vinyl monomers, ethylenically unsaturated carboxylic acid ester monomers, ethylenically unsaturated carboxylic acid amide monomers, ethylenically unsaturated nitrile monomers and the like can be used.

The neutralized alkali-soluble copolymer is obtained by neutralizing the alkali-soluble copolymer with a base. In this case, usable bases include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; hydroxides of alkaline earth metals such as calcium hydroxide and magnesium hydroxide; ammonia; triethylamine, triethanolamine Amines; and the like. Among them, ammonia is preferable.

In the acrylic (co) polymer constituting the acrylic emulsion for anti-slip of the present invention, the core (co)
The weight ratio of the polymer to the alkali-soluble copolymer is 4
0 / 60-85 / 15, preferably 60 / 40-80
/ 20. When the ratio of the shell portion is low outside the above range, the resulting coated paper has poor slip resistance, and when it is high, the blocking resistance is poor.

In the acrylic (co) polymer constituting the acrylic emulsion for anti-slip of the present invention, the (co)
The ratio of the total weight of the polymer and the alkali-soluble copolymer to the weight of the (co) polymer of the shell part is 20/80 to 50/5.
0, preferably 25/75 to 45/55. When the ratio of the shell portion is low outside the above range, the coated paper obtained has poor slip resistance, and when it is high, the blocking resistance is poor.

The anti-slip acrylic emulsion of the present invention has an average particle size of 300 to 1,000 nm, preferably 4 to 1,000 nm.
It is 00 to 800 nm. If the average particle size is smaller than 300 nm, the anti-slip property is reduced, and if it is larger than 1,000 nm, the transparency of the coating layer is reduced.

The acrylic emulsion for anti-slip of the present invention comprises:
Copolymerization of a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and a monomer comprising another ethylenically unsaturated monomer copolymerizable therewith in the presence of a core (co) polymer emulsion The emulsion thus obtained can be manufactured by adjusting the pH to 7 or more, and then further adding and polymerizing a monomer for constituting the (co) polymer of the shell portion. Hereinafter, this method is referred to as a first manufacturing method.

As a method for producing the (co) polymer emulsion of the core portion, from the viewpoint of controlling the particle size, a seed polymerization method is usually employed. In the presence of seed particles, usually, an emulsifier is not used and the core portion is prepared. Are added all at once before the start of the polymerization or dividedly or continuously added after the start of the polymerization to carry out the polymerization. In the case of divided addition or continuous addition, the addition amount can be made uniform or can be changed according to the progress of polymerization. At this time, the composition of the seed particles is not particularly limited, and may be the same as or different from the composition of the monomer. Further, the particle diameter and the amount of the seed particles may be appropriately selected according to the purpose.

In producing the (co) polymer emulsion having a core portion, a monomer having a high hydrophilicity such as 2-hydroxyethyl (meth) acrylate and an ethylenically unsaturated carboxylic acid monomer is contained in the monomer. The emulsion can be produced with high stability by containing the. Among these highly hydrophilic monomers, 2-hydroxyethyl (meth) acrylate is preferred. These highly hydrophilic monomers are usually used in an amount of 0.1 to 5% by weight in the composition of the core (co) polymer. When the amount is less than 0.1% by weight, the polymerization stability is not sufficiently imparted. When the amount is more than 5% by weight, the viscosity of the emulsion becomes high, so that handling becomes difficult.

In the first production method, the alkali-soluble copolymer is a monomer comprising a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and another ethylenically unsaturated monomer copolymerizable therewith. In the presence of the (co) polymer emulsion of the core portion, the body is added at a time at the start of polymerization, or a part is added at the start of polymerization, and then the remaining portion is added continuously or intermittently. It is added continuously from the start of the polymerization and copolymerized.

In the first production method, the alkali-soluble copolymer may be polymerized in the same reaction vessel subsequent to the polymerization of the nucleus, or the (co) polymerization of the nucleus previously polymerized in another reaction vessel. The combined emulsion may be transferred and polymerized.

The alkali-soluble copolymer is neutralized by adjusting the pH of the obtained emulsion to 7 or more with a base.

Next, a monomer for constituting the (co) polymer of the shell portion is continuously added to the dispersion-stabilized emulsion and polymerized.

After removing the unreacted monomer from the emulsion, the pH and the concentration are adjusted to obtain the acrylic emulsion for anti-slip of the present invention.

In the first manufacturing method, the (co)
The polymerization initiator that can be used for the polymerization of the polymer, the alkali-soluble copolymer and the (co) polymer of the shell portion is not particularly limited. Specific examples include sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate,
Inorganic peroxides such as hydrogen peroxide; diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1,3,3
3-tetramethylbutyl hydroperoxide, 2,
Organic peroxides such as 5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, di-α-cumyl peroxide, acetyl peroxide, isobutyryl peroxide, benzoyl peroxide; azo Bisisobutyronitrile, azobis-
Examples include azo compounds such as 2,4-dimethylvaleronitrile and methyl azobisisobutyrate. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used depends on the type thereof, but is based on the total amount of the monomers used in the polymerization of the core (co) polymer, the alkali-soluble copolymer and the shell (co) polymer. , 0.1-2.0
% By weight, preferably 0.2 to 1.0% by weight.

These polymerization initiators can be used as a redox polymerization initiator in combination with a reducing agent. The reducing agent of the redox polymerization initiator is not particularly limited, and specific examples thereof include compounds containing metal ions in a reduced state such as ferrous sulfate and cuprous naphthenate; sulfones such as sodium methanesulfonate; Acid compounds; amine compounds such as dimethylaniline; and the like. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent varies depending on the reducing agent, but is preferably 0.03 to 1 with respect to 1 part by weight of the polymerization initiator.
It is preferably 0 parts by weight.

In the first production method, as the emulsifier, generally, only a polymerizable emulsifier which can be used for producing an alkali-soluble copolymer may be used. Other emulsifiers may be used as long as the object of the present invention is not impaired. Examples thereof include commonly used nonionic, anionic, cationic or amphoteric surfactants.

In the first production method, the polymerization temperature for producing the core (co) polymer, the alkali-soluble copolymer and the shell (co) polymer is usually from 0 to 100 ° C. Preferably it is 30-90 degreeC.

Further, the acrylic emulsion for anti-slip of the present invention, when polymerizing a monomer for constituting the (co) polymer of the shell portion, comprises a simple monomer for constituting the (co) polymer of the shell portion. Is obtained by polymerizing a monomer comprising a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and other ethylenically unsaturated monomers copolymerizable therewith. It can also be prepared by emulsifying with a hydrate and polymerizing in the presence of a core (co) polymer emulsion. Hereinafter, this method is referred to as a second manufacturing method.

The (co) polymer emulsion of the core portion is produced in the same manner as in the method of producing the first (co) polymer of the core portion.

Next, the monomer constituting the (co) polymer of the shell portion is emulsified using an alkali-soluble copolymer neutralized product, and the emulsion is prepared in the presence of the (co) polymer emulsion of the core portion. The emulsion is added continuously to polymerize. At this time, the core (co) polymer emulsion is adjusted to pH 7 or more with a base. This stabilizes the dispersion of the alkali-soluble copolymer neutralized product emulsifying the monomer for constituting the (co) polymer of the shell portion. The amount of the neutralized alkali-soluble copolymer used is 20 to 100% by weight, preferably 20 to 50% by weight, based on 100 parts by weight of the monomer constituting the shell.
% By weight. If this amount is less than 20% by weight,
Emulsification stability deteriorates, and if it exceeds 100% by weight, the viscosity becomes high and handling becomes difficult.

In the second production method, the (co)
The method for producing the neutralized alkali-soluble copolymer emulsifying the monomers constituting the polymer is not particularly limited, and the alkali-soluble copolymer produced by emulsion polymerization or solution polymerization is adjusted to pH 7 or more with a base. To produce and neutralize. For example, in the case of emulsion polymerization, a copolymer obtained by polymerizing a monomer composed of a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer, and other ethylenically unsaturated monomers copolymerizable therewith. The combined emulsion is p
Neutralize and produce by adjusting to H7 or higher.

In the second production method, the monomers constituting the (co) polymer of the shell portion are polymerized following the polymerization of the core portion.
The polymerization may be carried out in the same reaction vessel, or the (co) polymer emulsion of the core portion previously polymerized in another reaction vessel may be transferred to carry out the polymerization.

After removing the unreacted monomer from the emulsion, the pH and the concentration are adjusted to obtain the acrylic emulsion for anti-slip of the present invention.

In the second manufacturing method, the (co)
As the polymerization initiator that can be used for the polymerization of the polymer, the alkali-soluble copolymer, and the (co) polymer of the shell portion, those that can be used in the first production method can be used.

In the second production method, when the alkali-soluble copolymer is produced by emulsion polymerization, only the above-mentioned polymerizable emulsifier may be used. Other emulsifiers may be used as long as the object of the present invention is not impaired. Examples thereof include commonly used nonionic, anionic, cationic or amphoteric surfactants.

In the second production method, the polymerization temperature for producing the (co) polymer of the core portion, the alkali-soluble copolymer and the (co) polymer of the shell portion is the same as in the first production method. The temperature is usually 0 to 100 ° C, preferably 30 to 90 ° C.

The acrylic emulsion for anti-slip of the present invention has anti-slip performance even when the emulsion is used alone, but can be used as a coating composition for anti-slip by mixing with a filler.

The filler used in the anti-slip coating composition of the present invention is not particularly limited, and may be an inorganic filler or an organic filler. Examples of the inorganic filler include titanium oxide, aluminum oxide, silicon dioxide, calcium carbonate, barium sulfate, and the like.As the organic filler, cellulose beads,
Examples thereof include crosslinked polystyrene particles, powdered resin such as acryl and vinyl chloride, and the like.

The filler usually has a volume average particle size of 2 to 30.
Those having 0 μm and a ratio of weight average particle diameter / number average particle diameter of 3.0 or less are used. The volume average particle size of the filler is 2μ
If it is less than m, the unevenness of the coated surface is insufficient, so that the slip resistance is reduced. If it is more than 300 μm, the transparency is undesirably reduced. When the ratio of the weight average particle diameter / the number average particle diameter is more than 3.0, the slip resistance deteriorates, which is not desirable.

The content of these fillers is usually 30 parts by weight or less, preferably 20 parts by weight or less, more preferably 1 part by weight, based on 100 parts by weight of the solid content of the acrylic emulsion.
0 parts by weight or less. If the amount is more than 30 parts by weight, not only is the slip resistance reduced, but also the blending stability when preparing the anti-slip coating composition and the transparency of the layer coated with the coating are undesirably reduced.

The anti-slip coating composition of the present invention can be prepared by a conventional method. At this time, additives such as an antifoaming agent, a thickening agent, a preservative, and a film-forming auxiliary which are usually used in this field can be mixed with the composition.

The acrylic emulsion for anti-slip and the coating composition for anti-slip of the present invention can be applied to a coating machine such as a roll coater, a blade coater, a bar coater and the like on a paper container such as a cardboard box and a carton, and various paper bags. They can be used and coated to give them excellent anti-slip properties.

[0063]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Unless otherwise specified, “parts” and “%” represent “parts by weight” and “% by weight”, respectively. The weight of the emulsion is in terms of solid content.

Example 1 In a polymerization vessel equipped with a stirrer and purged with nitrogen, 0.05 parts of seed emulsion particles (particle diameter: 50 nm) composed of polymethyl methacrylate, 87.1% of styrene, 2-ethylhexyl acrylate 9%
Then, 30.8 parts of a monomer mixture comprising 1.0% of 2-hydroxyethyl methacrylate and 65% of deionized water and 65 parts of ion-exchanged water were charged, and the mixture was heated to 70 ° C. while stirring, and potassium persulfate was added to 2 parts of deionized water. An initiator aqueous solution in which 0.1 part was dissolved was added and reacted for 4 hours to obtain a copolymer emulsion of a core portion. At this time, the polymerization conversion was 98%, and the volume average particle size was 430 nm.

Next, 9.2 parts of a monomer mixture composed of 28.6% of ethyl acrylate, 43.9% of styrene and 27.5% of methacrylic acid, ammonium salt of polyoxyethylene nonylpropenyl phenyl ether sulfate 0.
09 parts, 0.74 parts of octyl thioglycolate and 6.8 parts of ion-exchanged water were added all at once, and an aqueous initiator solution in which 0.05 part of potassium persulfate was dissolved in 1 part of ion-exchanged water was added. The reaction was performed for 1 hour. At this time, the polymerization conversion of all the monomers was 99%, and the volume average particle diameter was 490 nm. 1.8 parts of 28% ammonia water was added as a neutralizing agent, the pH was adjusted to 7.5, and the temperature was raised to 80 ° C.

Further, after adding an aqueous initiator solution in which 0.3 part of potassium persulfate was dissolved in 6 parts of ion-exchanged water, 88.0% of ethyl acrylate and 12.0% of acrylonitrile were added.
% Of the monomer mixture over 3 hours,
Thereafter, the mixture was aged for 2 hours to coat the shell portion of the copolymer. The polymerization conversion of all the monomers after the completion of the polymerization by cooling with water was 99%. After removing the unreacted monomer from the emulsion, the pH and concentration were adjusted to obtain an emulsion having a solid content of 50% and a pH of 7.0. The volume average particle diameter of the obtained emulsion was 670 nm.

Example 2 13.8 parts of a monomer mixture composed of 28.6% of ethyl acrylate, 43.9% of methyl methacrylate and 27.5% of methacrylic acid was placed in a polymerization vessel equipped with a stirrer and purged with nitrogen. , 0.25 part of polyoxyethylene nonylpropenyl phenyl ether sulfate ammonium salt, 0.49 part of t-dodecyl mercaptan and 25.7 parts of ion-exchanged water, and stirred to emulsify;
After the temperature was raised to 70 ° C., an aqueous initiator solution in which 0.2 part of potassium persulfate was dissolved in 4 parts of ion-exchanged water was added and reacted for 1 hour. After cooling the reaction solution, 2.8 parts of 28% aqueous ammonia was added as a neutralizing agent, the pH was adjusted to 7.5, and a neutralized alkali-soluble copolymer was obtained. After adding 27 parts of ion-exchanged water thereto, 88.0% of ethyl acrylate was added.
Then, 55 parts of a monomer mixture consisting of acrylonitrile and 12.0% of acrylonitrile were added to obtain an emulsion of monomers constituting the (co) polymer of the shell portion.

On the other hand, in another polymerization vessel equipped with a stirrer purged with nitrogen, 0.08 parts of seed emulsion particles (particle diameter: 50 nm) composed of polymethyl methacrylate, styrene 9
9.0% and 2-hydroxyethyl methacrylate
After charging 31.2 parts of a monomer mixture consisting of 0% and 38 parts of ion-exchanged water, heating the mixture to 70 ° C. with stirring, 0.1 parts of potassium persulfate was dissolved in 2 parts of ion-exchanged water. An aqueous solution of the agent was added and reacted for 4 hours to obtain a copolymer emulsion of a core portion. At this time, the polymerization conversion rate was 98.
%, And the volume average particle diameter was 370 nm. Then 2
0.2 parts of 8% aqueous ammonia was added to adjust the pH of the polymerization system to 7.5. Further, the temperature was raised to 80 ° C., and an aqueous solution of an initiator in which 0.5 part of potassium persulfate was dissolved in 10 parts of ion-exchanged water was added. The emulsion was added over 3 hours and then aged for 2 hours to cover the shell copolymer. The polymerization conversion rate of all the monomers after the polymerization was terminated by water cooling was 9
9%. After removing the unreacted monomer from the emulsion, the pH and concentration were adjusted so that the solid concentration was 50%.
%, PH 7.0 was obtained. The volume average particle diameter of the obtained emulsion was 540 nm.

(Examples 3-6, Comparative Examples 1-2) As shown in Table 1, the same procedures as in Example 1 were carried out except that the monomer composition, the amount of seed particles, the amount of the polymerizable emulsifier and the chain transfer agent were changed. I got an emulsion. Table 1 shows the average particle size of the obtained emulsion.

Comparative Example 3 In a polymerization vessel equipped with a stirrer and purged with nitrogen, 0.05 parts of seed emulsion particles (particle diameter: 50 nm) composed of polymethyl methacrylate, 87.1% of styrene, 2-ethylhexyl acrylate 9%
And 40 parts of a monomer mixture consisting of 1.0% of 2-hydroxyethyl methacrylate and 65% of ion-exchanged water, and the mixture was heated to 70 ° C. with stirring.
An aqueous solution of an initiator in which 0.1 part of potassium persulfate was dissolved was added thereto, and the mixture was reacted for 4 hours to obtain a copolymer emulsion having a core portion. At this time, the polymerization conversion was 98%, and the volume average particle size was 470 nm.

Next, separately, in a vessel equipped with a stirrer purged with nitrogen, 60 parts of a monomer mixture composed of 95.0% of ethyl acrylate and 5.0% of acrylonitrile, 60 parts of ion-exchanged water, and polyoxyethylene nonylpropenyl 0.5 part of phenyl ether sulfate ammonium salt was charged, stirred and emulsified to obtain an emulsion of a monomer constituting the (co) polymer of the shell portion. The emulsion was added over 3 hours and then aged for 2 hours to cover the shell copolymer. The polymerization conversion of all the monomers after the completion of the polymerization by cooling with water was 99%. From the emulsion,
After removing unreacted monomers, adjust the pH and concentration,
An emulsion having a solid content of 50% and a pH of 7.0 was obtained. The volume average particle diameter of the obtained emulsion is 670 n.
m.

[0072]

[Table 1]

(Example 7) The solid content of the emulsion obtained in Example 1 was diluted to 37%, and the liner paper for cardboard was prepared using a high-speed sheet-fed coater. 3. At a speed of 999 mm / sec, the coating amount is 2.5 to
After coating to 3.5 g / m ² , it was dried in an oven at 110 ° C. for 1 minute. The coated paper was heated at a temperature of 23 ° C.
The humidity was controlled for 24 hours under the condition of a humidity of 65%. The physical properties of the obtained coated paper were evaluated. Table 2 shows the results.

[0074]

[Table 2]

(Examples 8 to 12, Comparative Examples 4 to 6) As shown in Table 2, using the emulsions of Examples 2 to 6 and Comparative Examples 1 to 3, in the same manner as in Example 7, the coated paper Was prepared and its physical properties were evaluated. Table 2 shows the results.

(Example 13) 100 parts of the solid content of the emulsion obtained in Example 1 was mixed with 9 parts of vinyl chloride polymer particles (PB-52, manufactured by Shin-Daiichi PVC Co., Ltd .; particle size: 20 μm). Using the obtained composition, a coated paper was produced in the same manner as in Example 7, and the physical properties were evaluated. Table 2 shows the results.

[Evaluation Method of Emulsion] The method of measuring the anti-slip property and anti-blocking property of the emulsion is as follows. (Slip resistance) Slip resistance is determined by sliding angle test TAPPI standard method T
23 ° C., according to the gradient test specified in 503,
The slip angle of the coated paper was measured and evaluated using a level protractor (manufactured by Toei Kogyo Co., Ltd.) under the condition of a humidity of 65%. That is, first, the obtained coated paper is cut to produce test pieces of 2.5 cm × 17 cm and 7.5 cm × 20 cm. A test piece of 7.5 cm × 20 cm is attached to the main body of the machine such that the coated surface is facing up. next,
A test piece of 2.5 cm × 17 cm is attached to a metal plate having a test surface of 2.5 cm × 15 cm and a weight of 375 g so that the coated surface is turned upside down. The metal plate was placed on the center of the machine so that the test pieces were in contact with each other, the metal plate was gradually inclined, and the angle at which the metal plate began to slide was measured. The larger the angle, the higher the slip resistance.

(Blocking resistance) The coated paper was cut,
Two test pieces of 6.7 cm × 10 cm are prepared. The coated surfaces were put together and 29.4 under conditions of 40 ° C. and 90% humidity.
A load of KPa was applied, left for 18 hours, taken out and allowed to cool to room temperature, and then the test piece was peeled off with both hands. The test piece was evaluated according to the following criteria based on the degree of peeling state. Evaluation criteria ○: Difficult to peel, but no adhesion of the other paper to one paper △: Hard to peel, little adhesion of the other paper to one paper ×: Not peeled

From the evaluation results of the coated paper in Table 2, the following can be understood. The coated paper of Comparative Example 4 obtained using an emulsion in which the amount of the ethylenically unsaturated nitrile monomer in the shell portion is smaller than the range specified in the present invention has poor slip resistance. The coated paper of Comparative Example 5 obtained by using an emulsion having a volume average particle size smaller than the range specified in the present invention has poor slip resistance. The coated paper of Comparative Example 6 obtained using an emulsion which was not stabilized by the alkali-soluble copolymer had poor blocking resistance.

On the other hand, it is understood that the coated papers of Examples 7 to 13 using the emulsion and the coating composition of the present invention are excellent in the slip resistance and the blocking resistance.

[0081]

According to the present invention, an emulsion of a double-structured acrylic (co) polymer composed of a core portion and a shell portion having a specific particle size and stabilized by dispersion with a neutralized alkali-soluble copolymer. The core (co) polymer glass transition temperature, the shell (co) polymer composition, the glass transition temperature, and the core (co) polymer, alkali-soluble copolymer and core When an acrylic emulsion having a weight ratio with the (co) polymer in a specific range is used, a coated paper excellent in anti-slip properties and blocking resistance can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C09D 5/02 C09D 5/02 133/00 133/00 151/06 151/06 // C08L 51:06 C08L 51:06 F-term (reference) 4F070 AA17 AA18 AA32 AA33 AA34 AA35 AA36 AB08 CA01 CB12 4J011 KA06 KA09 KA10 KA15 KA21 KB08 KB14 KB19 KB29 4J026 AA16 AA17 AA43 AA44 AA45 AABA BA03 BA09 BA25BA03 DB08 FA07 GA01 GA02 GA09 4J038 CG031 CG141 CG161 CP071 MA08 MA10 MA13

Claims (4)

[Claims] 1. An emulsion of a double-structured acrylic (co) polymer composed of a core portion and a shell portion and having an average particle diameter of 300 to 1000 nm, which is dispersion-stabilized with a neutralized alkali-soluble copolymer. So, the core
The glass transition temperature (Tg) of the polymer is 30 to 110 ° C., and the (co) polymer of the shell portion is 2 to 15% by weight of an ethylenically unsaturated nitrile monomer unit and other ethylene copolymerizable therewith. Having a Tg of −50 to + 20 ° C. and a weight ratio of the (co) polymer of the core portion to the alkali-soluble copolymer of 40/60. And the ratio of the total weight of the core (co) polymer and the alkali-soluble copolymer to the weight of the shell (co) polymer is 20/80 to
An acrylic emulsion for anti-slip which is 50/50. 2. A monomer comprising a polymerizable emulsifier, an ethylenically unsaturated carboxylic acid monomer and another ethylenically unsaturated monomer copolymerizable therewith in the presence of a (co) polymer emulsion of a core portion. The emulsion obtained by copolymerizing the monomer is adjusted to a pH of 7 or more, and thereafter, a monomer for constituting the (co) polymer of the shell portion is added and polymerized. Item 4. The method for producing an acrylic emulsion for anti-slip according to Item 1. 3. In polymerizing a monomer for forming the (co) polymer of the shell portion, a monomer for forming the (co) polymer of the shell portion is converted into a polymerizable emulsifier, ethylene The polymer is obtained by polymerizing a monomer comprising an unsaturated unsaturated carboxylic acid monomer and another ethylenically unsaturated monomer copolymerizable therewith, and emulsifying with a neutralized product of a copolymer to form a core portion. (Co)
A method for producing an acrylic emulsion for anti-slip which comprises polymerizing in the presence of a polymer emulsion. 4. An anti-slip coating composition comprising the anti-slip acrylic emulsion according to claim 1 and a filler.