JPH08231887A - Anti-fogging agent composition - Google Patents

Abstract

PURPOSE: To obtain an anti-fogging agent composition capable of giving, even to the surface of a resin molded product containing a plasticizer, anti-fog properties that last for a long period of time. CONSTITUTION: An anti-fogging agent composition comprises (A) an emulsion of a copolymer having a glass transition temperature of 30 deg.C or lower obtained by subjecting a monomer mixture made up of (a) 60 to 99wt.%, one or more compounds selected from (meth)acrylic acid alkyl esters whose alkyl group has 1 to 18 carbon atoms and monoalkenylbenzenes, (b) 1 to 20wt.% one or more monomers selected from ethylenically unsaturated monomers having a functional group, and (c) the balance of one or more of ethylenically unsaturated monomers other than the above ones to emulsion polymerization in the presence of a free-radical polymerization initiator using a reactive surface-active agent and (B) an inorganic colloid sol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifogging composition, and in particular, it has excellent durability because it solves poor adhesion due to migration of plasticizer when applied to a soft vinyl chloride resin film or the like. The present invention relates to a clouding agent composition.

[0002]

2. Description of the Related Art Generally, molded articles and the like manufactured from a thermoplastic resin have fine water droplets formed on the surface thereof due to the condensation of water vapor in the atmosphere, depending on changes in conditions such as temperature and humidity used. Adhesion and fogging occur. For example, in food packaging films, the contents are difficult to see due to cloudiness, and in agricultural films used for greenhouses, cloudiness impairs the transmission of sunlight and hinders the growth of plants, and water droplets on cultivated plants. The buds fall and cause damage and disease. In order to solve these problems, a method of kneading a hydrophilic substance such as a surfactant into a thermoplastic resin to prepare a molded article, or a method of coating the surface with a hydrophilic substance after molding, is used to prevent various problems. A clouding agent composition is provided. However, none of these methods has been found to satisfy both antifogging performance and durability at the same time, and particularly in molded articles containing a plasticizer, poor adhesion caused by migration of the plasticizer to the surface over time. The drawbacks of have not been solved.

[0003]

In view of the above situation, it goes without saying that the present invention, when applied to the surface of a thermoplastic resin molded article, imparts excellent water resistance and long-lasting antifogging property. The present invention has been made in order to provide a composition capable of exhibiting excellent anti-fogging property without lowering the adhesiveness after aging even in a resin molded product containing a plasticizer.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a monomer is used in a specific range and a reactive surfactant is used as a surfactant to initiate radical polymerization. It was found that the problem could be solved by combining an emulsion of a specific range of (meth) acrylic or monoalkenylbenzene-based copolymer emulsion-polymerized in the presence of an agent with an inorganic colloid sol,
Further, the present invention was accomplished by conducting tests on the types and amounts of the monomer and the reactive surfactant.

That is, the present invention has solved the above-mentioned problems. It is (A) (a) an alkyl ester of (meth) acrylate having an alkyl group having 1 to 18 carbon atoms and a monoalkenylbenzene. 60% to 99% by weight of one or more types of monomers selected from the group (b) One or more types of monomers selected from ethylenically unsaturated monomers having a functional group 1- 20% by weight (c) A monomer mixture consisting of the balance of one or more ethylenically unsaturated monomers other than the above (a) and (b) [(a)-(c) total 100% by weight] ], Obtained by emulsion polymerization in the presence of a radical polymerization initiator using a reactive surfactant as a surfactant,
The gist is an antifogging agent composition comprising a copolymer emulsion having a glass transition temperature of 30 ° C. or lower and (B) an inorganic colloid sol.

The present invention will be described in detail below. In the emulsion of the copolymer which is the constituent (A) in the composition of the present invention, the monomers of the components (a) to (c) are used as raw materials as described above. The monomer of component (a) has an alkyl group with 1 carbon atom.
~ 18 (meth) acrylic acid alkyl ester, that is, acrylic acid ester with alcohol having C1-18 alkyl group, methacrylic acid ester with alcohol having C1-18 alkyl group, and monoalkenylbenzenes The one selected from is used. (Meta)
Specific examples of the alkyl group having 1 to 18 carbon atoms in the acrylic acid alkyl ester include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group and a capryl group. Base,
Examples thereof include nonyl group, decyl group, lauryl group, myristyl group, cetyl group and stearyl group, and examples of monoalkenylbenzenes include styrene, α-methylstyrene and vinyltoluene. The acrylic acid ester, methacrylic acid ester, styrene and the like are used alone or as a mixture of two or more kinds, and the amount of the acrylic acid ester, the methacrylic acid ester and the styrene is used in order to obtain appropriate film-forming property, coating strength, durability and the like. Of these, usually 60 to 99% by weight, but preferably 80 to 99
% By weight.

Examples of the ethylenically unsaturated monomer having a functional group (b) include a carboxyl group or its anhydride, a hydroxyl group, an amide group, an amino group, in addition to the ethylenically unsaturated group in one molecule, Examples thereof include those having a functional group such as an alkoxyl group and a glycidyl group, and those having two or more ethylenically unsaturated groups in one molecule. Examples of such a monomer include a carboxyl group such as acrylic acid, methacrylic acid and maleic anhydride, or an anhydride-containing monomer thereof, 2-hydroxyethyl (meth) acrylate, 2-
Hydroxyl group-containing monomer such as hydroxypropyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth)
Amide group-containing monomers such as acrylamide and diacetone (meth) acrylamide, amino group-containing monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl ( Alkoxyl group-containing monomers such as (meth) acrylate, glycidyl (meth)
Acrylate, glycidyl group-containing monomer such as glycidyl allyl ether, divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc.
Examples thereof include monomers having two or more ethylenically unsaturated groups in the molecule. The ethylenically unsaturated monomer having a functional group may be used alone or in combination of two or more. The amount of this monomer used is 1 to 20% by weight, preferably 2 to 16% by weight, based on the total amount of the monomers in order to improve the water resistance and plasticizer resistance of the coating film. If it is less than 1% by weight, the water resistance and plasticizer resistance of the coating film are inferior, and good antifogging property cannot be maintained for a long time. If it exceeds 20% by weight, agglomerates are not formed during polymerization. It will occur more often, and no further improvement in performance can be obtained.

The component (c) is an ethylenically unsaturated monomer other than the components (a) and (b), and imparts physical properties and coating film characteristics that cannot be exhibited by the components (a) and (b) alone. In addition, acrylonitrile, vinyl acetate, vinyl propionate, etc. can be used, but these are used in an amount of 20% by weight or less based on the total amount of the monomers so as not to impair the object of the present invention.

The reactive surfactant for producing the emulsion used in the present invention has a hydrophobic group and a hydrophilic group having a sufficient number of carbon atoms to exert the surface-active ability and has a micelle forming ability. , And having a radically polymerizable group, examples of which include:

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[0010]

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Examples thereof include nonionic reactive surfactants such as the above, or cationic reactive surfactants having a radical polymerizable group and a group in the form of a quaternary ammonium salt or a tertiary amine salt. This reactive surfactant is effective in improving the water resistance and plasticizer resistance of the coating film, and one kind thereof may be used or two or more kinds thereof may be used in combination, but if the amount is too small, A lot of agglomerates are generated in the produced emulsion, and the obtained coating film does not show good water resistance and plasticizer resistance. If the amount is too large, the particle size of the emulsion particles becomes fine, the viscosity of the emulsion rises too much, and the polymerization rate decreases, and the water resistance of the coating film also deteriorates. Therefore, the amount of the reactive surfactant used is preferably 0.5 to 15% by weight, more preferably 1 to 7% by weight, based on the total monomers.

Further, as long as the object of the present invention is not impaired, it is possible to use a non-reactive surfactant used in ordinary emulsion polymerization in combination with this reactive surfactant, and the total amount of the surfactant. Of these, 20% by weight or less may be used alone or in combination of two or more. These non-reactive surfactants include anionic surfactants such as alkyl or alkylallyl sulphates, alkyl or alkylallyl sulfonates and dialkyl sulfosuccinates, and cationic such as alkyl trimethyl ammonium chloride and alkyl benzyl ammonium chloride. Examples include surfactants, nonionic surfactants such as polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, and polyoxyethylene carboxylic acid ester.

As the radical polymerization initiator for producing the emulsion used in the present invention, potassium persulfate,
Persulfate such as ammonium persulfate, hydrogen peroxide solution, t-
Water-soluble types such as butyl hydroperoxide, azobisamidinopropane hydrochloride, benzoyl peroxide, cumene hydroperoxide, dibutyl peroxide, diisopropyl peroxydicarbonate, cumyl peroxyneodecanoate, cumyl peroxy octoate Oil-soluble types such as azobisisobutyronitrile and the like. Further, if necessary, N, N-dimethylaniline, acidic sodium sulfite, Rongalit,
A redox system in which a reducing agent such as ascorbic acid is also used can be used. The amount of the polymerization initiator used is usually 0.01 to 5% by weight based on all the monomers, but more preferably 0.05 to 2% by weight.

In order to produce the emulsion used in the present invention, first, various monomers described above are mixed, a surfactant is added thereto, and a polymerization initiator and the like are further combined to polymerize in an aqueous system. In this case, methods such as batch charge polymerization and polymerization while continuously supplying each component can be applied. The polymerization is usually carried out at a temperature of 10 to 90 ° C with stirring.

The glass transition temperature of the copolymer obtained by polymerization is required to be 30 ° C. or lower, and when it is higher than 30 ° C., good adhesion with a soft vinyl chloride film and the formation of an antifogging agent are required. Good bonding strength with particles of silica, alumina, etc. after the film cannot be obtained. The glass transition temperature is determined by the following formula. 1 / Tg = Σ (wi / Tgi) Tg: Glass transition temperature of copolymer (absolute temperature display) Tgi: Glass transition temperature of homopolymer of monomer component (i) (absolute temperature display) wi: Copolymer weight Weight fraction of component (i) in coalescence

The inorganic colloidal sol used as the constituent (B) in the composition of the present invention includes inorganic aqueous colloidal particles such as silica, alumina, water-insoluble lithium silicate, iron hydroxide, tin hydroxide, titanium oxide and barium sulfate. Examples thereof include an aqueous sol in which water is dispersed in water or a hydrophilic medium by various methods, and from these, only one kind or a combination of two or more kinds can be used. The average particle size of the inorganic colloid sol used is preferably in the range of 5 to 100 nm, and if it is in this range, two or more kinds having different average particle sizes may be combined. If the average particle size is less than 5 nm, the stability of the inorganic colloid sol may be insufficient, and if it exceeds 100 nm, the coating film tends to be white and devitrified. The inorganic colloid sol imparts an antifogging effect, but the amount thereof is preferably 1 to 50 times the solid content of the copolymer emulsion of the constituent (A) in terms of solid content weight ratio. If the weight ratio is less than 1 time, not only the sufficient anti-fogging effect cannot be exhibited, but also the adhesiveness of the coating film becomes stronger, which may cause contamination such as dust. If the weight ratio exceeds 50 times, Not only is the antifogging effect not improved in proportion to the blended amount, but also the coating film formed after coating becomes cloudy, which is not preferable.

The composition of the present invention may optionally contain water, methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, diethylene glycol,
A liquid dispersion medium such as glycerin, benzyl alcohol, cellosolve acetate, etc. is further added, if necessary, as an antifoaming agent, a wetting agent, a surfactant, a plasticizer, a film-forming aid, a thickener,
Conventional additives such as pigments and pigment dispersants can be mixed.

[0018]

EXAMPLES The present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the examples. In the examples, parts and% are parts by weight and% by weight, respectively.
Indicates. Synthesis Example 1 A polymerization vessel equipped with a stirrer, a condenser, a thermometer, a nitrogen gas inlet and a raw material inlet was added with 81.5 parts of deionized water and reactive surfactant Eleminor JS-2 [manufactured by Sanyo Chemical Industry Co., Ltd. ] 2.6 parts and 2 parts of reactive surfactant ADEKA REASOAP NE-10 [trade name of Asahi Denka Kogyo Co., Ltd.] were charged, the temperature was raised to 70 ° C. with stirring to dissolve, and the atmosphere was replaced with nitrogen. To this, 3 parts of a 1% aqueous solution of ferrous sulfate and 10 parts of a 1% aqueous solution of ascorbic acid were added, and at the same time, 36 parts of methyl methacrylate and ethyl acrylate were added.
A mixture of 60 parts, acrylic acid 3 parts, N-methylol acrylamide 1 part and 0.25% hydrogen peroxide solution 10 parts was added, and the solution was uniformly added over 3 hours.
Hold at 70 ℃ for 2 hours and cool.
Neutralized in parts. The solid concentration of the obtained emulsion is 4
The viscosity was 9.8% and the viscosity was 530 cP. The glass transition temperature of the copolymer was 16.3 ° C.

The structural formula of the reactive surfactant used is as follows.

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Synthesis Examples 2 to 10 Polymerization was carried out in the same manner as in Synthesis Example 1 with the types and amounts of the monomers and surfactants shown in Table 1. The solid content concentration and viscosity of the obtained emulsion were as shown in Table 1. In addition,
Methyl methacrylate 37 parts, butyl acrylate 40 parts, acrylic acid 6 parts, glycidyl methacrylate 7 as monomers
When 10 parts of 2-hydroxyethyl methacrylate were used to carry out polymerization in the same manner as in Synthesis Example 1, coagulation was generated and a normal emulsion could not be obtained.

[Table 1]

The structural formulas of the reactive surfactants other than those mentioned above in Table 1 are as follows. Further, Emal O is sodium lauryl sulfate, Neoperex No. 6 is sodium dodecylbenzene sulfonate, Emulgen 950 is polyoxyethylene nonyl phenyl ether, and Emulgen 810 is polyoxyethylene octyl phenyl ether.

[Chemical 4]

Example 1 (Preparation of antifogging agent composition) 20 parts of the emulsion obtained in Synthesis Example 1 was placed in a stainless steel container and stirred with a stirrer equipped with a propeller, Snowtex OL [colloidal silica, particle size 45 nm]. , Solid content 20%, Nissan Chemical Co., Ltd. product name] 4
0.5 parts of SURFINOL 440 [defoaming agent, trade name of Air Products and Chemicals] and 30 parts of deionized water were added, and stirring was continued for 1 hour to obtain an antifog composition. This solid content is 20% (silica / copolymer weight ratio =
It was 8/1).

(Evaluation of Properties) The obtained anti-fogging composition was applied onto an agricultural soft vinyl chloride film so as to have a thickness of about 3 μm, and dried for 1 minute in a hot air dryer at 90 ° C. for testing. It was a piece. With respect to the obtained test piece, the adhesion of the coating film, the plasticizer resistance, the antifogging property and the water resistance were measured. The results are shown in Table 2. In addition, the measurement of each characteristic was performed as follows. a. Adhesion of coating film A commercially available adhesive tape (Nichiban, cellophane tape) is applied to the surface of the test piece on which the antifogging agent composition is applied, and the adhesive tape is peeled off after being strongly rubbed with the nail 5 times. The adhesiveness between the coating film on the surface from which the adhesive tape was peeled off and the vinyl chloride film was observed. The evaluation results are indicated by ◯: good, Δ: somewhat bad, and x: bad. b. Plasticizer resistance After the test piece was left in an atmosphere of 50 ° C for 30 days, the influence of the plasticizer transfer on the adhesion was evaluated by the same method as the measurement of the adhesion of the coating film, and the results are shown in Table 2. It was c. Anti-fogging property Place the test piece on the top of the water tank with the coated surface facing the inside of the water tank, keep the outside air temperature at 20 ° C and the inside air temperature at 55 ° C for 1 hour after placing the sample on the water tank. The state of water droplets on the subsequent coated surface was visually observed. Evaluation results ◯: No water droplets are observed, Δ: Large water droplets are partially observed, ×: Fine water droplets are partially observed d. The water resistant test piece was immersed in deionized water for 24 hours and then taken out, and the whitening state of the coating film was visually observed. Evaluation results ◯: No whitening, △: Little whitening, ×: Significant whitening

Examples 2 to 6 and Comparative Examples 1 to 5 Example 1 except that the type and amount of copolymer emulsion and the type and amount of inorganic colloid sol shown in Table 2 were blended.
An antifogging agent composition was prepared in the same manner as above, evaluated by the same method, and the results are shown in Table 2.

[0025]

[Table 2]

[0026]

EFFECT OF THE INVENTION The antifogging composition of the present invention has good antifogging property, excellent adhesion and water resistance of the obtained coating film, and further when applied to a soft vinyl chloride resin film. It has excellent durability and does not cause changes in adhesion due to migration of plasticizer. Due to this characteristic, the antifogging composition of the present invention is extremely advantageous practically.

Claims (1)

[Claims] 1. A monomer of (A) (a) alkyl group having 1 to 18 carbon atoms, selected from alkyl (meth) acrylates and monoalkenylbenzenes. To 99% by weight (b) One or more monomers selected from ethylenically unsaturated monomers having a functional group 1 to 20% by weight (c) Other than (a) and (b) A monomer mixture consisting of the balance of one or more ethylenically unsaturated monomers and the rest (total of 100% by weight of (a) to (c)) is radical-treated by using a reactive surfactant as a surfactant. Obtained by emulsion polymerization in the presence of a polymerization initiator,
An antifogging agent composition comprising a copolymer emulsion having a glass transition temperature of 30 ° C. or lower and (B) an inorganic colloid sol.