JP2003192866A - Acrylic resin organosol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-viscosity acrylic resin organosol capable of giving semi-rigid thin films which are suitable as marking films, have high weatherability and scarcely cause bleeding, and generate no toxic gas even if burnt after discarded. <P>SOLUTION: This acrylic resin organosol is obtained by compounding (A) 100 pts.wt. of an alkyl (meth)acrylate-based polymer, (B) 20-60 pts.wt. of a plasticizer and (C) 10-50 pts.wt. of a diluent which is prepared by mixing a cellosolve-based diluent or a trialkylpentanediol carboxylic ester with another diluent in the weight ratio of (10:90) to (90:10). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an acrylic resin organosol, and more particularly to an acrylic resin organosol suitable for obtaining a semi-hard thin film with less bleed.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resin organosols have good workability and have been used for marking films, strippable coatings, brittle films, coated steel sheets and the like. However, vinyl chloride resin products have a problem that weather resistance deterioration such as browning and generation of black spots occurs when they are used in applications where they are exposed to ultraviolet rays for a long period of time. In addition, with respect to the problem that hydrochloric acid gas is generated when incinerating waste products, in recent years, a film product that does not emit hydrochloric acid gas even when incinerated has been demanded from the viewpoint of environmental protection.

In order to solve these problems, it has been attempted to use a methyl methacrylate polymer (acrylic resin), which is a polymer containing no chlorine in the molecule, in place of the vinyl chloride resin. Molded products made of acrylic resin have excellent transparency and weather resistance, and have the advantage that they do not generate hydrochloric acid gas when burned. However, since the acrylic resin is less compatible with the diluent than the vinyl chloride resin and the specific gravity is 1.2 relative to 1.4 of the vinyl chloride resin, the dispersion medium is 15 to obtain the same sol viscosity. Since a large amount is required in the order of about% by weight, there is a problem that bleeding is more likely to occur in the molded product. Therefore, the appearance of an acrylic resin organosol in which bleeding is less likely to occur in a molded product is desired.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a semi-hard thin film suitable for a marking film, which has good weather resistance and is less likely to cause bleeding, and which does not generate a harmful gas even when a waste product is burned. It was made for the purpose of providing a low-viscosity organosol that can be obtained.

[0005]

Means for Solving the Problems As a result of intensive studies in view of the above situation, the present inventors have found that by combining a plasticizer and a diluent with an alkyl (meth) acrylate polymer, It was found that the desired organosol can be obtained, and the present invention has been completed based on this finding. Thus, according to the present invention, the following (1) to (5)
Will be provided. (1) 100 parts by weight of (A) alkyl (meth) acrylate-based polymer and (B) plasticizer 20-60
An acrylic resin organosol obtained by mixing 10 parts by weight of (C) diluent with 10 parts by weight of (C) diluent. (2) The (A) alkyl (meth) acrylate-based polymer has a tetrahydrofuran insoluble content of 10 to 90% by weight.
The acrylic resin organosol according to (1) above, which is an alkyl (meth) acrylate-based polymer containing (3) The acrylic according to (1) above, wherein the (A) alkyl (meth) acrylate polymer is an alkyl (meth) acrylate polymer in which 0.2 to 5% by weight of a carboxyl group is bonded in the molecule. Resin organosol. (4) The (C) diluent is a cellosolve-based diluent or a trialkylpentanediol carboxylic acid ester,
The acrylic resin organosol according to (1) above, which is mixed with another diluent at a weight ratio of 10/90 to 90/10. (5) An acrylic resin marking film formed by molding the acrylic resin organosol according to any one of (1) to (4) above. Further, the following (6) is provided as a preferred embodiment of the present invention. (6) The (C) diluent has an average particle size of 0.05 to 5 μm.
In the above (1), the viscosity of the suspension in which the (A) alkyl (meth) acrylate polymer of m is dispersed in a concentration of 50% by weight is 100 Pa · s or less after standing at 23 ° C. for 24 hours. The acrylic resin organosol described.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) used in the present invention is an alkyl (meth) acrylate polymer (hereinafter sometimes referred to as an "acrylic resin").
The repeating unit derived from an acrylate monomer is 50% by weight or more, preferably 50 to 99.8% by weight, and the repeating unit derived from a monomer copolymerizable with an alkyl (meth) acrylate monomer is 50% by weight or less. , Preferably 50-0.2
It is a polymer containing wt%. Where alkyl (meta)
The acrylate monomer is a (meth) acrylate (meaning acrylate or / and methacrylate) having an alkyl group having 1 to 8 carbon atoms. The alkyl (meth) acrylate monomer is preferably a monomer having a homopolymer glass transition temperature of 60 ° C. or higher. Examples of such a monomer include methyl methacrylate, whose homopolymer has a glass transition temperature of 105 ° C, and 65 ° C.
Examples include ethyl methacrylate, 81 ° C., isopropyl methacrylate, 107 ° C., t-butyl methacrylate, and the like.

As the monomer copolymerizable with the alkyl (meth) acrylate monomer, aromatic vinyl compounds such as styrene, vinyltoluene and α-methylstyrene;
Vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as ethyl vinyl ether, cetyl vinyl ether and hydroxybutyl vinyl ether; α-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
Examples thereof include a hydroxyl group- or alkoxy group-containing unsaturated carboxylic acid ester compound such as hydroxybutyl (meth) acrylate and butoxyethyl (meth) acrylate.

The weight average molecular weight of the component (A) alkyl (meth) acrylate polymer is usually 100,000.
~ 4,000,000, preferably 200,000 ~
It is 3,000,000. If the weight average molecular weight is too low, a uniform molded product may not be obtained, while if it is too high, the plasticizer may bleed from the molded product.
The single average particle diameter of the alkyl (meth) acrylate polymer as the component (A) is preferably 0.05 to 5.0 μm, more preferably 0.3 to 3.0 μm. If it is less than 0.05 μm, the viscosity of the organosol formed from it will be high, and if it is more than 5.0 μm, sedimentation may occur easily during storage of the organosol. Here, the single average particle size means that the polymer powder is dispersed in water, the mixture is placed in an ultrasonic shaker with an oscillating frequency of 50 kHz for 1 minute, and then left standing for 3 minutes. A cumulative particle size distribution is obtained by a formula particle size distribution measuring device, and the cumulative value is expressed by a particle size (also referred to as "median size") having a cumulative value of 50% by weight.

A polymer consisting only of repeating units derived from an alkyl (meth) acrylate monomer, and a copolymer which is copolymerizable with a repeating unit derived from an alkyl (meth) acrylate monomer and an alkyl (meth) acrylate monomer A copolymer consisting of a repeating unit derived from the monomer of
Generally, the polymer particles are likely to be swollen by the plasticizer, so that the viscosity tends to increase remarkably when stored for a long time, particularly when stored at a high temperature of 30 ° C. or higher in summer.
Therefore, the alkyl (meth) acrylate polymer as the component (A) is preferably one of the following two types capable of improving this problem. That is, the alkyl (meth) acrylate polymer is (A1) an alkyl (meth) acrylate polymer containing 10 to 90% by weight of tetrahydrofuran-insoluble matter, and / or (A2) has 0 carboxyl groups in the molecule. It is preferable to use an alkyl (meth) acrylate-based polymer having 2 to 5% by weight bonded thereto, since it gives a plastisol having good storage stability of viscosity.

Tetrahydrofuran component (A1) (hereinafter sometimes referred to as "THF") insoluble matter 10
The alkyl (meth) acrylate-based polymer containing 90 to 90% by weight is a cross-linked polymer, and for example, 60 to 99.5% by weight of alkyl (meth) acrylate monomer and 0.5% of polyfunctional monomer. It can be produced by copolymerizing ˜15% by weight and 0 to 40% by weight of another copolymerizable monomer. The (A1) component alkyl (meth) acrylate-based polymer is a THF-insoluble cross-linked polymer in an amount of 10 to 90.
By containing the composition in an amount of 30% by weight, preferably 30 to 70% by weight, swelling due to a plasticizer is unlikely to occur, and therefore the viscosity of plastisol is unlikely to increase even under a summer temperature of 30 to 40 ° C. That is, the viscosity stability over time is good. THF
If the insoluble content is too large, the plasticizer may bleed from the molded product. When the (A) alkyl (meth) acrylate polymer is the component (A1), the average molecular weight is exceptionally infinite because it is a cross-linked polymer insoluble in THF. However, the weight average molecular weight of the THF-soluble component is usually 5,000.
It is 0 to 7,000,000.

Examples of the polyfunctional monomer include epoxy group-containing monomers such as glycidyl (meth) acrylate, glycidyl-p-vinylbenzoate, methylglycidyl itaconate, allyl glycidyl ether and methallyl glycidyl ether; diallyl phthalate. , Polyallyl allyl compounds such as diallyl maleate, diallyl adipate and triallyl cyanurate; ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, trimethylolpropane di (meth ) Polyfunctional (meth) s such as acrylate, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, oligoethylene di (meth) acrylate
Acrylate; ethylene glycol divinyl ether,
Divinylbenzene etc. can be mentioned.

The method of incorporating a carboxyl group into the alkyl (meth) acrylate polymer of the component (A2) is not particularly limited. For example, the content of the carboxyl group in the alkyl (meth) acrylate monomer and the copolymer is A method of copolymerizing the carboxyl group-containing monomer in an amount of 0.2 to 5% by weight and, if necessary, another monomer copolymerizable therewith. As the alkyl (meth) acrylate monomer and the other copolymerizable monomer, the same monomer as the monomer that can be used for producing the component (A1) can be used. The alkyl (meth) acrylate-based polymer as the component (A2) contains a carboxyl group in an amount of 0.2 to 5% by weight, preferably 0.5 to 4% by weight, more preferably 1 to 3% by weight. Swelling due to is less likely to occur. If the carboxyl group content is too high, the plasticizer may bleed from the molded product. The content of the repeating unit derived from the alkyl (meth) acrylate monomer in the component (A2) is 50 to
It is 99.8% by weight, preferably 55 to 95% by weight.
If the content of the repeating unit is too small, the component (A2) may not have properties as an acrylic resin, and conversely, if the content is too large, the stability of the sol viscosity with time may decrease.

Examples of the carboxyl group-containing monomer include
It is not particularly limited as long as it can be copolymerized with an alkyl (meth) acrylate, and examples thereof include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethylacrylic acid, crotonic acid and cinnamic acid; maleic acid and itaconic acid. Unsaturated dicarboxylic acids such as fumaric acid, citraconic acid and chloromaleic acid; monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monofumarate-
Examples thereof include monoesters of unsaturated dicarboxylic acids such as 2-hydroxyethyl, monomethyl itaconate, monoethyl itaconate and monobutyl itaconate, and their derivatives. Further, the above-mentioned unsaturated dicarboxylic acid anhydride can also be used as a monomer for imparting a carboxyl group to the produced polymer.

The method for producing the alkyl (meth) acrylate polymer as the component (A) is not particularly limited, and for example, it can be produced by emulsion polymerization, seed emulsion polymerization, fine suspension polymerization, seed fine suspension polymerization and the like. it can. The polymerization temperature is not particularly limited, but is preferably 30 to 80 ° C.

The latex containing the alkyl (meth) acrylate polymer particles obtained by the polymerization reaction is dried by spray drying using an inert gas such as nitrogen, and then pulverized if necessary to obtain copolymer particles. Can be obtained. In the present invention, the weight average molecular weight of the alkyl (meth) acrylate-based polymer as the component (A) is obtained by dissolving 0.5 g of the polymer in 100 ml of THF (if the insoluble content is 2% by weight or less, remove it). , Ignore and measure)
By gel permeation chromatography (GPC) using THF as a solvent using a mixed gel column,
It is measured in terms of standard polystyrene.

The organosol of the present invention contains a plasticizer as the component (B). As the plasticizer, any of those usually used for softening acrylic resins can be used. Examples of such a plasticizer include phthalic acid ester, isophthalic acid ester, tetrahydrophthalic acid ester, benzoic acid ester, adipic acid ester, azelaic acid ester, sebacic acid ester, maleic acid ester, fumaric acid ester, trimellitic acid. Examples thereof include esters, pyromellitic acid esters, citric acid esters, itaconic acid esters, oleic acid esters, ricinoleic acid derivatives, stearic acid esters, other fatty acid esters, phosphoric acid esters, and alkyl sulphonic acid phenol esters.

Specifically, as the phthalate ester,
Dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, dicyclohexyl phthalate, diphenyl phthalate, butyl benzyl phthalate, octyl Benzyl phthalate, dibenzyl phthalate, etc .; as isophthalic acid ester, di- (2-ethylhexyl) isophthalate, diisooctyl isophthalate, etc .; as tetrahydrophthalic acid ester, di-2-ethylhexyl tetrahydrophthalate, etc .; benzoic acid ester As diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol Such Lumpur dibenzoate;

As the adipic acid ester, di- (2-
Ethylhexyl) adipate, dibutoxyethyl adipate, diisononyl adipate, polyethylene glycol adipate, etc .; as sebacate ester, di-
n-hexyl azelate, di- (2-ethylhexyl)
Azelaic acid esters such as azelate; di-n-butyl sebacate and the like; maleic acid esters include di-
n-Butyl maleate, di- (2-ethylhexyl) maleate, etc .; as fumaric acid ester, di-n-butyl fumarate, di- (2-ethylhexyl) fumarate, etc .; as trimellitic acid ester, tri- ( Two
-Ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, etc .; as pyromellitic acid ester, tetra- (2-
Ethylhexyl) pyromellitate, tetra-n-octylpyromellitate, etc .; as citric acid ester, tri-n-butyl citrate, acetyltri- (2-ethylhexyl) citrate, propenyl tributyl citrate, etc .; as itaconic acid ester, Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- (2-ethylhexyl) itaconate, etc .; As oleic acid ester, glyceryl monooleate, diethylene glycol monooleate, etc .;

Examples of the ricinoleic acid derivative include glyceryl monoricinolate and diethylene glycol monoricinolate; stearic acid esters include glycerin monostearate and diethylene glycol distearate; and other fatty acid esters including diethylene glycol dipelargonate and penta Erythritol fatty acid ester and the like; as phosphoric acid ester, tributoxyethyl phosphate, triphenyl phosphate,
Examples thereof include tricresyl phosphate, decyl diphenyl phosphate, octyl diphenyl phosphate, and alkyl sulfonic acid phenol ester. Among them, phthalic acid ester, phosphoric acid ester, benzoic acid ester, citric acid ester and alkylsulfonic acid phenol ester are preferable. These plasticizers may be used alone or in combination of two or more.

In the present invention, the compounding amount of the component (B) plasticizer is 20 to 60 parts by weight, preferably 30 to 5 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate polymer.
0 parts by weight. If the blending amount of the plasticizer is too small, the film may be too hard and brittle, and may be easily cut. On the contrary, if the blending amount is too large, the film may easily bleed and may be easily scratched.

The diluent used as the component (C) in the organosol of the present invention is an organic solvent which is insoluble in the acrylic resin, can be uniformly mixed with the plasticizer, and reduces the viscosity of the organosol with a small amount of addition. In addition, it has the property of volatilizing when heated to gel the organosol. The diluent usually has a boiling point of 1
It is preferably about 00 to 200 ° C. The diluent is
It is mixed with the acrylic resin of component (A) together with the plasticizer of component (B), and volatilizes in the process of heating and gelation. Almost all of the plasticizer remains in the molded product, while almost no diluent remains. Any diluent conventionally used in vinyl chloride resin organosols can be used as the diluent in the present invention. In the present invention, among such diluents, as a measure of insolubility in an acrylic resin, an (A) alkyl (meth) acrylate polymer having an average particle diameter of 0.05 to 5 μm is used as a diluent in a concentration of 50. The viscosity of the suspension prepared by dispersing it by weight is 2 at 23 ° C.
It is preferable to use a diluent having a viscosity of 100 Pa · s or less after being left for 4 hours.

Examples of such diluents include methyl cellosolve and dibutyl cellosolve (both manufactured by UCC, USA).
Naphthesol H-diluents such as Naphthesol H (manufactured by Nippon Petrochemical Co., Ltd.) and Shelsol H-naphthenic diluents;
Paraffin diluents such as normal paraffin M (manufactured by Nippon Petrochemical Co., Ltd.), Shellsol 71 (manufactured by Shell Chemical Co., Ltd.) and Supersol FP20 (manufactured by Idemitsu Kosan Co., Ltd.); carbitol diluents; kerosene; Chisso CS-12, Chisso CS-
Examples thereof include trialkylpentanediol carboxylic acid ester diluents such as 16; ketone diluents such as methyl ethyl ketone and methyl isobutyl ketone; alcohol diluents such as hexanol and octanol. Among these, especially cellosolve-based diluents and trialkylpentanediol carboxylic acid ester-based diluents,
Since the acrylic resin has good dispersibility and hardly swells the acrylic resin, the viscosity of the organosol is lowered and it is difficult to increase the viscosity during storage, which is preferable. Also,
These two diluents are unlikely to bleed even if they remain even after heating and gelling the acrylic resin. Therefore, in the present invention, at least 40% by weight of these two diluents is used.
When the diluent contained is used, the acrylic resin organosol has good castability, and thus a thin film can be stably produced.

The cellosolve-type diluent is an ether compound of alkylene glycol, and is typically a compound having a chemical structure represented by the following general formula (I). ^{R 1 -O-R 2 -O-} R 3 (I) provided that, ^{R 1} represents an alkyl group having 1 to 8 carbon atoms, ^{R 2}
Represents a divalent hydrocarbon group having 1 to 6 carbon atoms, and R ³ represents hydrogen or an alkyl group having 1 to 8 carbon atoms. As an example of a cellosolve-based diluent, R ² is preferably a hydrocarbon group having 2 carbon atoms, and when R ³ is hydrogen, methyl-2-oxyethyl ether (methyl cellosolve), ethyl-2
-Oxyethyl ether (ethyl cellosolve), propyl-2-oxyethyl ether (propyl cellosolve), butyl-2-oxyethyl ether (butyl cellosolve), isoamyl-2-oxyethyl ether (isoamyl cellosolve), octyl-2-oxyethyl Ether (octyl cellosolve) and the like can be mentioned. When R ³ is an alkyl group, ethyl-2-ethoxyethyl ether (diethyl cellosolve), ethyl-2-
Propoxy ethyl ether, butyl-2-butoxy ethyl ether (dibutyl cellosolve), octyl-2-butoxy ethyl ether and the like can be mentioned.

The alkyl groups in the trialkylpentanediol carboxylic acid ester do not necessarily have to have the same three groups as long as they have 1 to 8 carbon atoms. The carboxylic acid is preferably a carboxylic acid having 1 to 8 carbon atoms and may be a diester or a monoester. Typical examples of trialkylpentanediol carboxylic acid esters include 2,
2,4-trimethyl-1,3-pentanediol diisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diacetate, 2,2,4-trimethyl-
1,3-pentanediol monoisobutyrate, 2,
2,4-trimethyl-1,3-pentanediol diisobutyrate and the like can be mentioned.

In the present invention, the compounding amount of the diluent as the component (C) is 100% by weight of the alkyl (meth) acrylate polymer.
10 to 50 parts by weight, preferably 15 to 10 parts by weight
40 parts by weight. If the compounding amount of the diluent is too small, the viscosity of the organosol may be high, and the processability may deteriorate.On the contrary, if it is too large, foaming may occur in the heating process or bleeding may occur in the product without sufficient volatilization. There is a possibility that it is not preferable. In particular, a cellosolve-based diluent or trialkylpentanediol carboxylic acid ester and another diluent are used at a weight ratio of 10/90 to 90/10, preferably 2
It is preferable to use it in a mixture of 0/80 to 80/20 because the viscosity stability of the acrylic resin organosol with time is improved.

To the organosol of the present invention, a pigment, a filler, an antistatic agent, an antiblocking agent, a surfactant and the like can be optionally added as long as the object of the present invention is not impaired.

As the pigment, titanium oxide is often used in order to improve weather resistance, and phthalocyanine blue, yellow lead, carbon black, red iron oxide, etc. are used.

The method for preparing the organosol of the present invention is not particularly limited and, for example, using a grinder, a kneader, a planetary mixer, a horizontal paddle mixer, a butterfly mixer, a dissolver, an intensive mixer, etc., the above component (A), ( The component B) and the component (C) can be prepared by further thoroughly mixing the above optional components depending on the circumstances.

Since the organosol of the present invention has a good sol casting property, it can be used for producing marking films, strippable coatings, brittle films, coated steel sheets and the like. Marking films that are widely used for various stickers, especially for advertisements and signs, have weather resistance, transparency, dry touch (non-bleeding), semi-hardness (not too soft and not too hard), Since the organosol of the present invention is required to have excellent adhesiveness and the like, the organosol of the present invention can be applied very suitably.

There is no limitation on the method for producing the marking film. For example, the organosol of the present invention is spread on a metal sheet, a plastic sheet, a paper, a PET film or the like by a spread coating method, a calendar method, a T-die method or the like to have a thickness of 30. ~ 200μm coating, 1 in the oven
It can be obtained by heating at 50 to 300 ° C. to gel. The organosol of the present invention has a viscosity of 200 to 5000 mPas.
・ Low viscosity at s, good castability, and shear rate of 1,000
Even if it is applied at a high speed of ˜10,000 cm ⁻¹ , it can be applied thinly without leaving an uncoated portion. The marking film obtained by gelling is excellent in the above-mentioned various properties such as weather resistance required for the marking film, and does not generate toxic gas such as hydrochloric acid gas when incinerating a waste product.

[0031]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, "part" and "%" are based on weight unless otherwise specified. Various operations and tests are based on the following methods. Characteristics of (A) alkyl (meth) acrylate polymer (1) Weight average molecular weight of 40 ° C, 500 mg of a resin sample subjected to vacuum drying treatment at a vacuum degree of -755 mmHg for 3 hours was added to 100 ml of tetrahydrofuran as a reagent, and at room temperature. Dissolved for 24 hours (disregarding the insoluble matter when it is present in an amount of 2% by weight or less is ignored), and then subjected to GPC using a mixed gel column with THF as an eluent, which is measured by referring to the retention time of standard polystyrene. To do. The THF-insoluble matter is removed before measurement. (2) THF insoluble matter 40 ° C, 500 mg of a resin sample subjected to vacuum drying treatment at a vacuum degree of -755 mmHg for 3 hours was added to 50 ml of tetrahydrofuran as a reagent, dissolved in room temperature for 24 hours, and then centrifuged at 8000 rpm. It is taken for 10 minutes, then filtered off, dried at 60 ° C. for 24 hours, and then weighed.

(3) Carboxyl Group Content Using the latex after polymerization, the content of the acid monomer component is measured by conductivity titration using a standard titration solution of potassium hydroxide and hydrochloric acid. Acrylic acid monomer is (a) particle layer,
(B) It is present in the serum layer. First, the number of moles of the carboxyl group present in the serum layer is determined by conductivity titration, and then the amount of the serum layer present is subtracted from the total amount of the acid monomers used in the reaction to obtain the particle layer present, which is converted to the weight% of the amount of the carboxyl group. . (4) Single average particle size Using the latex after polymerization, the median diameter of the single particle size distribution measured using a laser diffraction scattering particle size distribution measuring device (LA-300 manufactured by Horiba Ltd.) The average particle size is used.

(B) Characteristics of diluent (1) Poor solvent property of diluent (A) Alkyl (meth) acrylate polymer 1 described later
A suspension in which 50 parts of the diluent was dispersed in 50 parts of the diluent was allowed to stand at 23 ° C. for 24 hours, the viscosity was measured, and evaluated according to the following criteria. ◯: 50 Pa · s or less Δ: 50 Pa · s or more, 100 Pa · s or less ×: 100 Pa · s or more (C) Organosol characteristics (1) Initial viscosity Viscous components of the types and amounts shown in Table 1 are collectively crushed The mixture is mixed at room temperature for 10 minutes by a machine, and then defoamed for 15 minutes by a vacuum stirring defoaming machine having a vacuum degree of −755 mmHg to prepare an organosol for viscosity measurement. After the defoaming treatment, the sample was collected in a closed container, left at 23 ° C. for 1 hour, and then measured at 23 ° C. in an environment with a humidity of 60% to be the initial viscosity. The Brookfield viscometer L type was used as the viscosity meter, and the rotor No. 4 was measured at 60 rpm. Unit Pa ・
s. (2) Viscosity aging index Plastisol whose initial viscosity was measured was placed in a glass container, tightly sealed, and stored at 23 ° C for 1 hour, and then the viscosity was measured at 23 ° C in a room with a humidity of 60% in the same manner as the initial viscosity. To do.
The value of the ratio of the viscosity after 1 day to the initial viscosity is taken as the viscosity aging index. For practical use, 5 or less is necessary, and 2 or less is preferable.

(D) Molding characteristics and molded article characteristics (1) Transparency The organosol prepared in the same manner as in (iii) (1) above was applied onto a glass plate having a thickness of 2 mm to a thickness of 100 μm using a doctor blade. Then, the film was placed in an oven at a temperature of 180 ° C. for 10 minutes and then taken out, and the obtained film was measured with a light transmittance tester and evaluated according to the following criteria. ◯: Total light transmittance of 97% or more Δ: Total light transmittance of 92% or more ×: Total light transmittance of less than 92%

(2) Non-bleeding The film prepared by loading the same as (iv) (1) above
After left in a room at 3 ° C. and a humidity of 60% for 2 weeks, the plasticizer oozing on the film surface was visually inspected and evaluated according to the following criteria. ○: No bleeding is observed. Δ: A slight bleed is seen. X: Remarkable bleeding is observed.

[Production Example of Alkyl (meth) acrylate Polymer 1] In a stainless steel container, 97 parts by weight of methyl methacrylate and 3 parts of methacrylic acid as methacrylate monomers.
Parts by weight, 1.0 part by weight of sodium dodecylbenzenesulfonate as an emulsifier, 1.5 parts by weight of a higher alcohol having 18 carbon atoms as a dispersant, 0.3 part by weight of benzoyl peroxide as a polymerization initiator, and 150 parts by weight of deionized water. Was added, and the mixture was stirred and mixed at room temperature for 30 minutes, homogenized under high shear with a homomixer, transferred to a stainless steel polymerization vessel, and then polymerized under stirring at a polymerization temperature of 65 ° C. for 5 hours. After confirming a polymerization rate of 95% or more based on the solid concentration of the reaction solution sampled in a small amount, terminate the reaction,
A neutralization treatment was performed to obtain an acrylic resin latex. The latex was dried by a spray dryer with a nitrogen stream at 170 ° C., and further passed through a pulverizer sealed with nitrogen to obtain fine powder. The single average particle diameter of the particles of the alkyl (meth) acrylate polymer 1 thus obtained was 1.4 μm. The carboxyl group content is 1.3%, the methyl methacrylate monomer unit is 97.6%, and the weight average molecular weight is 1,80.
The amount of 50,000 and THF-insoluble matter was 0.9%.

"Production Example of Alkyl (meth) acrylate Polymer 2" Methyl methacrylate 95 as a monomer component
Parts and 5 parts of glycidyl methacrylate were used to obtain an acrylic resin latex in the same manner as in Production Example of alkyl (meth) acrylate polymer 1. 1 of the latex
The powder was dried by a spray dryer with a nitrogen stream at 70 ° C., and further passed through a pulverizer sealed with nitrogen to obtain fine powder. The single average particle diameter of the particles of the alkyl (meth) acrylate polymer 2 thus obtained was 1.5 μm. The THF-insoluble content was 53.3%.

Examples 1 to 10 and Comparative Examples 1 to 2 Organosols were prepared by mixing the components in the types and amounts shown in Table 1, films were formed, and the initial viscosity and viscosity aging index were measured by the above-mentioned test methods. The transparency and non-bleeding property were evaluated. The results are shown in Table 1. The following is a note on the ingredients in the table. (A) Plasticizer 1: benzoflex 2088 (dipropylene glycol dibenzoate, manufactured by Versicol) (b) Plasticizer 2: tricresyl phosphate (manufactured by Daihachi Chemical Co., Ltd.) (c) Diluent 1: butyl cellosolve (UCC) (D) Diluent 2: Dibutyl cellosolve (UCC) (e) Diluent 3: Chisso CS-16 (2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) ( Chisso Co., Ltd. (f) Diluent 4: Mineral Spirit A (paraffin hydrocarbons about 55%, naphthene hydrocarbons about 30%, aromatic hydrocarbons about 15%, initial distillation 152 ° C., end point 196 ° C.,
Nippon Oil Co., Ltd. (G) Diluent 5: Methyl isobutyl ketone (H) Diluent 6: Shellsol D40 (Naphthene hydrocarbon, Shell Chemical Co.) (Re) Diluent 7: Naphthesol H (Naphthene hydrocarbon) (Nippon Petrochemical Co., Ltd.) (nu) Diluent 8: Normal Paraffin M (Normal Paraffin, Nippon Petrochemical Co., Ltd.)

[0039]

[Table 1]

As shown in Table 1, the organosol of the present invention had a low viscosity, good castability, and high stability with time of viscosity. The films obtained using the organosol of the present invention had good transparency, moderate hardness and no bleeding (Examples 1 to 10). In particular, when a cellosolve-based diluent or a combination diluent of a trialkylpentanediol carboxylic acid ester and another diluent was used, the stability of viscosity with time was excellent (Examples 5 to 10). On the other hand, in Comparative Example 1 containing 10 parts of the plasticizer, a hard film was obtained and the transparency was lowered. In Comparative Example 2 containing 5 parts of the diluent, the organosol had a high viscosity, and it was difficult to form a film.

[0041]

Industrial Applicability According to the present invention, a low-viscosity film which is suitable as a marking film, has a good weather resistance, is a semi-hard thin film with little bleeding, and produces no harmful gas even when a waste product is burned. An organosol is provided.

Claims (5)

[Claims] 1. 100 parts by weight of an (A) alkyl (meth) acrylate polymer, and (B) a plasticizer 20 relative thereto.
-60 parts by weight and 10 to 50 parts by weight of the (C) diluent, an acrylic resin organosol. 2. The (A) alkyl (meth) acrylate-based polymer has a tetrahydrofuran insoluble content of 10 to 90.
The acrylic resin organosol according to claim 1, which is an alkyl (meth) acrylate-based polymer containing 10% by weight. 3. The (A) alkyl (meth) acrylate-based polymer is an alkyl (meth) acrylate-based polymer having a carboxyl group bonded in the molecule in an amount of 0.2 to 5% by weight. Acrylic resin organosol. 4. The (C) diluent is a cellosolve-based diluent or a trialkylpentanediol carboxylic acid ester and another diluent in a weight ratio of 10/90 to 90/10.
The acrylic resin organosol according to claim 1, which is a mixture of 5. An acrylic resin marking film obtained by molding the acrylic resin organosol according to claim 1.