JP3241797B2 - Surface treatment agent, coated polymer film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treating agent capable of imparting high antifogging property and anti-blocking property, a coated polymer film treated with the surface treating agent, and a method for producing the same.

[0002]

2. Description of the Related Art Generally, water vapor in the air is condensed on the surface of a hydrophobic synthetic resin film, sheet, plate, or the like as a result of changes in temperature and humidity to form fine water droplets. For this reason, the transparency is reduced, and a so-called fogging phenomenon often occurs.

For example, general-purpose (GP) polystyrene sheets have been used as various food packaging materials because of their excellent transparency, water resistance and moldability.

However, a container formed from this sheet contains
When vegetables are stored and packed and stored, 9
Since 0% is water, the water vapor evaporates from the surface and saturates the inside of the container, and the saturated water vapor condenses on the inner surface of the container and adheres as minute water droplets. As a result, it becomes difficult to identify the stored items due to the fogging. And the commercial value of the polystyrene sheet characterized by transparency is remarkably reduced. Further, the condensed and adhered water affects the fruits and vegetables stored in the container. In other words, when water drops and fruits and vegetables come into contact, rot of the fruits and vegetables starts at the contact site,
The quality of fruits and vegetables may be reduced early.

In the case of molding a container from a styrene-based polymer sheet or the like, a method of forming a large number of containers, stacking the molded containers, and punching the containers at once has been used.

However, in a molded article using a polymer sheet, the molded articles adhere to each other. Therefore, after the punching process, it is not only necessary to peel off the containers one by one,
Due to poor removability, the work efficiency for storing the contents is reduced. Furthermore, if the product is forcibly peeled off, the molded product may be damaged.

JP-A-53-115781 discloses that a surface of a thermoplastic resin film is subjected to a corona discharge treatment to a surface tension of 40 to 55 dyn / cm, and then a surfactant, an antifogging agent such as polyvinyl alcohol, and a silicone. It has been proposed to deposit oil. in this way,
The two types of incompatible properties can be uniformly attached to the sheet without agglomeration, and the surface appearance is good,
A film having both antifogging property and blocking resistance can be produced.

However, when moisture continuously contacts the film surface, the antifogging agent dissolves in water and flows out. Therefore, the anti-fogging function and the anti-blocking function cannot be maintained.
When the film or sheet is subjected to deep drawing,
The coating film is broken and broken. Therefore, the characteristics required for a styrene-based polymer sheet often used for food packaging cannot be satisfied.

Japanese Patent Publication No. 63-62538 discloses an aqueous solution containing a sucrose fatty acid ester, an unmodified polyvinyl alcohol having a degree of polymerization of 800 or less, and a silicone emulsion having an average particle size of less than 1 μm at a specific ratio. A method of applying to the surface is disclosed. According to this method, a styrene-based resin film having higher anti-fogging property than the above film can be obtained.

However, this film has a large degree of whitening before and after the molding of the container, and its commercial value is reduced. In addition, in order to maintain the anti-fogging property, the coating amount after drying needs to be 0.1 g / m ² or more. That is, if the coating amount is less than 0.1 g / m ² , not only the anti-fogging durability is small, but also the anti-fogging property of the molded container is greatly reduced.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high antifogging property and a high antiblocking property not only at the initial stage but also for a long period of time, even if the coating amount is small, and to divide the coating film by molding. It is to provide a surface treatment agent capable of suppressing the occurrence of the surface treatment.

Another object of the present invention is to provide a coated polymer film capable of maintaining high antifogging property and blocking resistance for a long period of time.

Still another object of the present invention is to provide a coated polymer film capable of maintaining high antifogging property and blocking resistance for a long period even when subjected to molding.

Another object of the present invention is to provide a method for producing a coated polymer film having the above-mentioned excellent properties by a simple operation.

[0015]

The present inventors have conducted intensive studies to achieve the above object, and have found that sucrose fatty acid esters, silicone emulsions, polysaccharides and / or hydrophilic polymers (excluding polyvinyl alcohol). When a polymer film or sheet is treated with a surface treatment agent containing, the coating by the surface treatment agent adheres uniformly and firmly, and the elution due to moisture is remarkably suppressed. The present inventors have found that high antifogging properties and anti-blocking properties can be maintained for a long period of time, and the present invention has been completed.

That is, the present invention provides a surface treating agent containing a sucrose fatty acid ester, a silicone emulsion, and a polysaccharide and / or a hydrophilic polymer (excluding polyvinyl alcohol).

Further, the present invention provides a coating layer comprising a sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer (excluding polyvinyl alcohol) on at least one surface of the polymer film. To provide a coated polymer film.

Further, the present invention provides a surface treatment comprising a sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer (excluding polyvinyl alcohol) on at least one surface of the polymer film. Provided is a method for producing a coated polymer film to which an agent is applied.

In this specification, the term "film" is used to mean not only a film but also a two-dimensional structure such as a sheet or a plate.

The surface treating agent of the present invention contains at least three components, namely, a sucrose fatty acid ester, a silicone emulsion, and a polysaccharide and / or a hydrophilic polymer. It is difficult to obtain a uniform coating film with a treating agent containing two components of a sucrose fatty acid ester and a silicone emulsion, and whitening, unevenness and stickiness of the coating film occur. In addition, the sucrose fatty acid ester flows out due to water wetting on the film surface, and the coating film is cut off by deep drawing, thereby lowering the commercial value.

On the other hand, in addition to the above two components, a polysaccharide and / or
Alternatively, with a surface treatment agent containing a hydrophilic polymer, the silicone emulsion is more stabilized, and the emulsion particles are uniformly dispersed and adhered uniformly. Therefore, there is no whitening of the coating film. The polysaccharide and / or hydrophilic polymer also functions as a binder to increase the adhesion strength of the coating film and to prevent the coating film from breaking even when the film is stretched by deep drawing. Further, despite the hydrophilicity of the polysaccharide and / or the hydrophilic polymer, the outflow of the antifogging agent due to water wetting on the film surface is remarkably suppressed, and the antifogging durability and the antifogging after forming the deep drawn container Excellent not only properties but also anti-blocking properties,
A film suitable for food packaging and the like can be obtained. In particular, even if the thickness of the coating film is small, the above-described excellent properties are imparted.

Examples of sucrose fatty acid esters include, for example,
Caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, saturated fatty acids having about 6 to 30 carbon atoms such as montanic acid, lindelic acid, palmitooleic acid, oleic acid, elaidin Acid, isooleic acid, erucic acid, linoleic acid,
And sucrose esters such as unsaturated fatty acids having about 10 to 24 carbon atoms such as linolenic acid. These sucrose fatty acid esters can be used alone or in combination of two or more. These sucrose fatty acid esters have high antifogging properties.

Among these sucrose fatty acid esters, saturated or unsaturated fatty acid esters having 8 to 20 carbon atoms, particularly saturated fatty acid esters, are preferred. Particularly preferred sucrose fatty acid esters include fatty acid esters having 10 to 18 carbon atoms,
Above all, fatty acid esters containing lauric acid as a main component are included. The fatty acid residue of the sucrose fatty acid ester is preferably composed mainly of lauric acid, particularly at least 50% or more of lauric acid.

As the silicone emulsion, various emulsions in which silicone oil is emulsified and dispersed can be used. The type of the silicone oil is not particularly limited, and examples thereof include an alkylpolysiloxane such as dimethylpolysiloxane, diethylpolysiloxane, and trifluoropropylpolysiloxane; an arylpolysiloxane such as diphenylpolysiloxane; and an alkylarylpolysiloxane such as methylphenylpolysiloxane. And the like. The silicone oil may be a linear polysiloxane or a cyclic polysiloxane. These silicone oils can be used alone or in combination of two or more. Among these silicone oils, dimethylpolysiloxane having no problem in safety and health is preferable.

The silicone emulsion has a high function as an antiblocking agent.

The viscosity of the silicone oil is not particularly limited, but is usually 50 to 1500 Ostwald viscosity at room temperature.
0 centistokes, preferably about 100 to 10000 centistokes.

The polysaccharides include, for example, single polysaccharides, complex polysaccharides and derivatives thereof. The polysaccharides include, for example, polysaccharides in plants and animals, starch derivatives, cellulose derivatives, and the like.

Examples of polysaccharides in animals and plants include starch, phytoglycogen, fructan, galactomannan, glucomannan, mannan, barley and oat glucan, cellulose, hemicellulose, β-1,3-glucan, galactan, araban, xylan , Arabogalactan, araboxylan, araboglucan, pectin, acacia, tragacanth, locust bean gum,
Guar gum, female kit rubber, carrageenin, glucuronoxylan, laminaran, inulin, lichenin, fructosan, chitin, chitosan, alginic acid, sodium alginate, hyaluronic acid, chondroitin sulfate, caronine sulfate, gelatin, agar, fucoidin, troloioi,
Curdlan, xanthan gum, pullulan, dextran,
Examples include cyclodextrin, nigeran, levan and the like.

Examples of the starch derivatives include white dextrin, yellow dextrin, British gum, oxidized starch, acid-treated starch, α-starch, high amylose starch, dialdehyde starch, acetate starch, sodium starch glycolate, and hydroxyethyl starch. , Starch phosphate, cationic starch,
Cross-linked starch, starch organic acid ester, starch inorganic acid ester,
Examples thereof include alkyl and substituted alkyl starch ethers, graft-polymerized starch, and derivatives thereof.

Examples of the cellulose derivative include methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, soluble cellulose acetate, cellulose sulfate, cellulose phosphate and the like.

Since these polysaccharides are used as foods and food additives, there is no problem in safety and hygiene even if they are used in polymer films often used for food packaging, for example, styrene-based polymer films. . These polysaccharides have a high function as a binder.

The hydrophilic polymer includes a water-soluble polymer other than polyvinyl alcohol, a water-dispersible polymer, and a water-swellable polymer. As the hydrophilic polymer, for example, a monomer having a hydroxyl group, a monomer having a carboxyl group, a monomer having an amide group, a monomer having a basic nitrogen atom alone or as a component Copolymers and polyvinyl ethers are included.

Examples of the monomer having a hydroxyl group include:
Examples thereof include hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate, and corresponding hydroxyalkyl methacrylates and polyethylene glycol mono (meth) acrylates.

As the monomer having a carboxyl group,
For example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like can be mentioned.

Examples of the monomer having an amide group include acrylamide and methacrylamide. Examples of the monomer having a basic nitrogen atom include, for example,
Examples include N-dimethylaminoethyl acrylate, N-diethylaminoethyl acrylate, methacrylate and vinylpyrrolidone corresponding thereto.

The hydrophilic polymer containing the monomer as a constituent may be a copolymer with a monomer such as an acrylate, a methacrylate or styrene.

The monomers constituting polyvinyl ether include, for example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isopropyl ether, vinyl butyl ether and vinyl isobutyl ether.

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

Preferred hydrophilic polymers include water-soluble polymers or water-dispersible polymers, especially water-soluble polymers. Particularly preferred hydrophilic polymers are those whose main chain does not have a hydrophilic group such as an ether group, is hydrophobic such as an alkylene group, and has a hydrophilic group such as an ester group, an ether group or a basic nitrogen atom in a side chain. Polymer.

[0040] Such hydrophilic polymers include acrylic polymers and vinyl polymers. Among them, a polymer having a carboxyl group or a salt thereof (for example, a (meth) acrylic acid-based polymer and a salt thereof) in a side chain, and a vinyl polymer having an ether group or a basic nitrogen atom (for example, polyvinyl ether, polyvinyl pyrrolidone) Such)
Is preferred. Examples of the salt of the (meth) acrylic acid-based polymer include an alkali metal salt such as a sodium salt and a potassium salt, an ammonium salt, and an organic amine salt.

Among the salts of the (meth) acrylic acid-based polymer,
Salts of acrylic acid polymers, particularly sodium polyacrylate, are preferred. Since sodium polyacrylate is approved as a food additive, there is no problem in terms of safety and health when used for a polymer film often used for food packaging, for example, a styrene-based polymer film.

The polysaccharide and the hydrophilic polymer may be used alone or in combination.

The proportion of the above components in the surface treatment agent can be appropriately selected within a range where the antifogging property and the antiblocking property are not impaired. For example, the proportion of the silicone emulsion is 20 to 1000 parts by weight, preferably 50 to 50 parts by weight, as a solid content based on 100 parts by weight of the sucrose fatty acid ester.
0 parts by weight, more preferably about 100 to 300 parts by weight.

The proportion of the polysaccharide is 10 to 1000 parts by weight, preferably 15 to 500 parts by weight, more preferably 30 to 500 parts by weight, based on 100 parts by weight of the sucrose fatty acid ester.
It is about 250 parts by weight.

Further, the ratio of the hydrophilic polymer is 10 to 100 parts by weight, preferably 15 to 75 parts by weight, more preferably 2 to 100 parts by weight based on 100 parts by weight of the sucrose fatty acid ester.
It is about 0 to 50 parts by weight.

When the polysaccharide and the hydrophilic polymer are used in combination, the amount of both used is based on 100 parts by weight of the sucrose fatty acid ester according to the ratio of the polysaccharide and the hydrophilic polymer. It can be selected within the range of 10 to 1000 parts by weight.

The surface treating agent may be, if necessary, various additives, for example, stabilizers such as antioxidants and ultraviolet absorbers;
An antifoaming agent; a filler; an antistatic agent; a plasticizer; a wax;

The surface treating agent is usually aqueous containing water. Aqueous surface treatment agents include, in addition to water, hydrophilic solvents such as alcohols such as methanol, ethanol and isopropanol; methyl cellosolve, ethyl cellosolve,
It may contain butyl cellosolve and the like.

The surface treating agent can be prepared using a conventional mixing stirrer or mixing and dispersing machine, and the silicone oil may be dispersed at the time of preparation.

The viscosity of the surface treating agent can be appropriately selected within a range that does not impair coatability. When the antifogging property and the anti-blocking property are enhanced by one application of the surface treatment agent, the viscosity of the surface treatment agent is, for example, 5000 cps or less, preferably about 10 to 2500 cps.

The coated polymer film of the present invention has a coating layer formed by the above-mentioned surface treating agent on one or both sides of the polymer film.

Examples of the polymer of the polymer film include olefin polymers such as polyethylene, ethylene-ethyl acrylate copolymer, ionomer, polypropylene, ethylene-propylene copolymer, poly-4-methylpentene-1, and polyvinyl alcohol. Vinyl chloride polymers such as ethylene-vinyl alcohol copolymers; polyvinyl chloride; vinylidene chloride polymers; styrene polymers; polyesters such as polyethylene terephthalate and polybutylene terephthalate;
Nylon or polyamide; polyacrylonitrile; polycarbonate; polyimide; polyphenylene oxide;
Polysulfone; polyparaxylene; polyamideimide;
Polyesterimides; cellulose derivatives and the like.

Preferred polymer films include films having processability. The polymer film is
It is preferable that the film is made of a hydrophobic synthetic resin film, for example, an olefin-based polymer (particularly, a polypropylene-based polymer), a polyester (particularly, polyethylene terephthalate), or a styrene-based polymer.

The styrene-based polymer includes a styrene homopolymer, styrene-based copolymer containing styrene as a constituent component, and a mixture containing these. More specifically, examples of the styrene-based polymer include general-purpose polystyrene (GPPS), rubber-reinforced polystyrene (high-impact polystyrene HIPS), polystyrene-polybutadiene-polystyrene block copolymer, and acrylonitrile-styrene copolymer (AS resin). ), ABS resin, styrene-butadiene block copolymer, AAS resin obtained by graft polymerization of acrylonitrile and styrene on acrylic rubber, ACS resin obtained by graft polymerization of acrylonitrile and styrene on chlorinated polyethylene, acrylonitrile on ethylene-propylene rubber (EPDM) Acrylonitrile-EPDM-styrene terpolymer obtained by graft polymerization of styrene, acrylonitrile- (ethylene-
A such as vinyl acetate copolymer) -styrene terpolymer
Examples thereof include an XS resin, a styrene-methyl methacrylate copolymer, and an acrylonitrile-styrene-methyl methacrylate copolymer. These styrenic polymers can be used alone or in combination of two or more.

Such a styrenic polymer film is excellent in water resistance and moldability. Therefore, it is suitable as a film for molding containers and the like. In addition, the polystyrene film has high transparency.

The polymer film may be made of various additives, for example, stabilizers such as antioxidants, ultraviolet absorbers, heat stabilizers, antistatic agents, crystal nucleus growth agents, hydrocarbon polymers, plasticizers, and fillers. , Dyes and pigments.

The polymer film may be a single-layer film or a laminated film in which two or more polymer layers are laminated. The thickness of the polymer film can be appropriately selected according to the application, and is, for example, about 10 μm to 5 mm, and preferably about 25 μm to 1 mm.

The polymer film can be obtained by a conventional film forming method such as a T-die method or an inflation method.

The polymer film may be unstretched, but is preferably stretched. The stretched film is
The film may be a uniaxially stretched film, but is preferably a biaxially stretched film, particularly a biaxially stretched styrene-based polymer film. Moreover, the stretched film may be heat-treated as necessary.

Examples of the stretching method include conventional stretching methods such as roll stretching, rolling stretching, belt stretching, tenter stretching, tube stretching, and a combination of these. The stretching ratio can be appropriately set according to the desired film properties, for example, 1.5 to 20 times, preferably 2 to 15 times.
It is about twice.

The surface of the polymer film may be subjected to a conventional surface treatment, for example, a corona discharge treatment, a high-frequency treatment and the like. The surface treatment of the polymer film is preferably performed by corona discharge. The surface tension of the polymer film varies depending on the type of the film, and cannot be unconditionally determined. However, the surface tension is about 35 to 65 dyn / cm when measured according to JIS K-6768 "Wetting test method for polyethylene and polypropylene films". In the case of a styrene-based polymer film, the surface tension is 40 to 60 dyn.
/ Cm, preferably about 45 to 58 dyn / cm.

When the surface of the polymer film having such a surface tension is treated with the above-mentioned surface treating agent, the coating film adheres firmly, and the durability of the coating film against water wetting on the film surface is improved. The surface tension of the film surface was 65 dyn /
If it exceeds cm, the film surface is likely to be activated too much or blocking is likely to occur. For this reason, it becomes difficult to rewind a film wound in a roll shape, or when a plurality of formed containers are stacked and punched out, the containers come into close contact with each other, and the work efficiency of separating the containers and storing the contents decreases. easy.

The surface treatment of the polymer film can be performed by a conventional method. The degree of the corona discharge treatment can be adjusted by the frequency, voltage, film passing speed, distance between the film and the electrode, ambient temperature and humidity, etc. of the corona discharge treatment machine.

The coated polymer film of the present invention having the coating layer formed thereon is free from whitening and stickiness, has an excellent surface appearance, does not leak out components of the coating layer against water wetting on the film surface, and is coated by deep drawing. The feature is that the layers are not divided. Further, even when the thickness of the coating layer is small or the coating layer is subjected to a molding process, there is a feature that high antifogging property is maintained.

The content of the sucrose fatty acid ester, silicone, polysaccharide and / or hydrophilic polymer in the coating layer is determined according to the composition ratio of the surface treatment agent in terms of anti-fogging property, anti-blocking property and coating resistance. It can be appropriately selected in consideration of the strength of the film. The coating layer containing the sucrose fatty acid ester, the silicone emulsion and the polysaccharide is, for example, a sucrose fatty acid ester of 10 to 50 mg / m ² (preferably 1
0 to 40 mg / m ² , more preferably 15 to 30 mg
/ M ² ), the silicone emulsion having a solid content of 10
１００100 mg / m ² (preferably 15-75 mg / m ²
m ^2, and more preferably 20~50mg / m ^2), a polysaccharide 5 to 100 mg / m ² (preferably 5 to 50 mg /
m ² , more preferably 5 to 30 mg / m ² ).

If the sucrose fatty acid ester is less than 10 mg / m ² , the antifogging property of the film surface is not improved, and
When the amount exceeds mg / m ² , the antifogging property is improved, but stickiness, whitening and unevenness are liable to occur, and the surface state is liable to decrease.
When the amount of the silicone emulsion is less than 10 mg / m ² , blocking of the film is liable to occur.
When the amount exceeds g / m ² , the blocking resistance is improved, but stickiness and whitening occur to impair the appearance. 5m polysaccharide
When it is less than g / m ² , the effect as a binder and the antifogging durability are reduced, the coating film is easily cut by deep drawing, and the antifogging property in a deep drawing container is easily reduced. On the other hand, when the amount of the polysaccharide exceeds 100 mg / m ² , the coating film tends to be whitened.

The coating layer containing the sucrose fatty acid ester, the silicone emulsion and the hydrophilic polymer contains 10-50 mg / m ^{2 of} sucrose fatty acid ester (preferably 10 to 50 mg / m ² ).
40 mg / m ² , more preferably 15 to 30 mg / m
² ), a silicone emulsion having a solid content of 10 to 1
00mg / m ² (preferably 15~75mg / m ^2, more preferably 20~50mg / m ^2), a hydrophilic polymer 1 to 50 mg / m ² (preferably 1.5～25Mg /
m ² , more preferably 2 to 20 mg / m ² ). When the component is out of the above range, the same tendency as that of the polymer film on which the coating layer containing the polysaccharide is formed is exhibited.

As is clear from the above, the coating amount of the surface treatment agent is, for example, about 20 to 250 mg / m ² , preferably about 25 to 150 mg / m ² .

The coated polymer film of the present invention has a feature that it has high antifogging durability even when the coating amount is small. For example, the coating amount after drying is 0.02 to 0.15 g /
Even if m ² , preferably about 0.05 to 0.1 g / m ² , the antifogging durability is high.

In the coated polymer film of the present invention, at least one surface of the polymer film may be treated with a surface treating agent. One surface is treated with a surface treating agent, and the other surface is treated with a surface treating agent.
It may be treated with various treating agents, for example, a silicone emulsion for further improving the anti-blocking property, and a coating agent containing an anti-static agent or a lubricant for improving the anti-static property or the slip property.

In the method for producing a coated polymer film of the present invention, a surface treatment agent containing a sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer is applied to at least one surface of the polymer film. I do.

The application of the surface treatment agent can be carried out using a conventional coating means, for example, a spray, a brush, a roll coater, a gravure roll coater, a knife coater, a dip coater and the like.

The surface treatment agent may be applied to the polymer film a plurality of times, but it is preferable to form the coating layer by a single application operation.

After applying the surface treating agent, the coating layer is usually dried to obtain the coated polymer film.

According to the method of the present invention, a polymer film having excellent antifogging properties and blocking resistance can be obtained by a simple operation of coating. Therefore, it is not necessary to knead an anti-fogging agent, an anti-blocking agent, and the like into a polymer to form a film, so that a blending step is not necessary, and a coated polymer film can be continuously and efficiently produced. Further, by continuously providing the coated polymer film to a molding step of a container or the like, productivity of a molded article can be increased.

The present specification discloses not only films but also molded articles such as containers coated with the surface treatment agent. This molded article also shows high antifogging property and antiblocking property. The molded article has at least a container body for storing articles. The opening of the container body may be covered with a wrapping film. Further, the molded article may include a container body and a lid that covers an opening of the container body via a hinge.

Such a molded article can be produced by applying the surface treating agent of the present invention to at least the inner surface of the container body by spraying or the like. In the case of a molded article having a lid, the inner surface of the lid may be treated with the surface treatment agent.

Preferred embodiments of the present invention are as follows.

(A) The silicone emulsion is an emulsion containing dimethylpolysiloxane having high safety and health.

(B) A surface treatment agent wherein the hydrophilic polymer is a polymer having a hydrophobic main chain and a side chain having a hydrophilic group.

(C) Surface treatment agent in which the hydrophilic polymer is an acrylic polymer (for example, poly (meth) acrylic acid polymer and its salt) or a vinyl polymer (for example, polyvinyl ether, polyvinylpyrrolidone, etc.) .

(D) A surface treating agent in which the hydrophilic polymer is a salt of an acrylic acid polymer.

(E) A coated polymer film wherein the polymer film is a film having moldability.

(F) The polymer film has a surface tension of 40
A coated polymer film that is a styrene-based polymer film of ６０60 dyn / cm.

(G) The coated amount of the surface treating agent after drying is 0.
Coated polymer film is 02~0.15g / m ^2.

[0086]

When the surface treating agent of the present invention is used, the following effects are produced.

(1) High antifogging property and blocking resistance can be imparted not only in the initial stage but also for a long period.

(2) It is possible to form a coating film which is not destroyed by heat and draw forming at the time of forming the container and does not flow out of the antifogging agent due to moisture.

(3) Stickiness and whitening can be suppressed, and the properties of the polymer film, such as transparency and gloss, are not impaired.

(4) The dispersion stability of the silicone emulsion can be enhanced by the polysaccharide and / or hydrophilic polymer.

(5) Since sucrose fatty acid esters, silicone emulsions and polysaccharides and / or hydrophilic polymers, which are approved as foods or food additives, can be used, there is no problem in terms of safety and health, Suitable as a treating agent.

The following effects are produced by the coated polymer film of the present invention.

(6) The coating layer is not destroyed by heat and drawing at the time of forming the container, and the antifogging agent in the coating layer does not flow out due to moisture. Can be maintained throughout.

(7) No stickiness or whitening, and excellent transparency and gloss.

(8) As described in the above (5), a surface treating agent having no problem in safety and health can be used, so that it is suitable as a food packaging material.

Further, according to the method of the present invention, a coated polymer film having the above-mentioned excellent properties can be efficiently produced by a simple operation of coating, in particular, a single coating operation.

[0097]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In Examples and Comparative Examples, the properties of the films were evaluated by the following methods.

(1) Surface Condition After applying and drying the surface treating agent, the sheet was left overnight in an atmosphere of 20 ° C. and 65% RH, and the stickiness and whitening state of the sheet surface were evaluated according to the following criteria.

：: No whitening, no stickiness X: Sticky or whitening (2) Initial anti-fogging property and anti-fogging continuity Put water at 20 ° C. in a cup, put the treated surface inside,
The top of the cup was covered and sealed, placed in a refrigerator kept at a temperature of 5 ° C., and the degree of cloudiness was visually evaluated with time. The initial antifogging property indicates the degree of fogging after 5 minutes, and the antifogging durability indicates the degree of fogging after 48 hours.

：: No fogging is observed at all. Δ: Fine water droplets are observed on a part of the treated surface, and the part is opaque.

×: Most of the treated surface is covered with minute water droplets and becomes opaque. (3) Appearance quality of molded article The sheet is 100 mm in diameter, 10 mm in depth (0.1 in deep drawing ratio), and 20 mm (0 in deep drawing ratio 0). .2), molded into three types of cylindrical containers of 30 mm (0.3% deep drawing ratio),
The bottom and corners of the container were evaluated for whitening.

：: No whitening X: At least a part of whitening is recognized (4) Antifogging sheet after forming the container is 100 mm in diameter, 10 mm in depth (deep drawing ratio 0.1), 20 mm (deep drawing) Molded into three types of cylindrical containers, each having a ratio of 0.2) and 30 mm (a deep drawing ratio of 0.3),
Water vapor generated from hot water at 80 ° C. was applied to determine the antifogging property at the bottom and corners of the container.

：: The bottom and corners of the container are not fogged. Δ: The bottom of the container is not fogged, but a part of the corner is fogged. ×: The bottom and the corner of the container are fogged. After immersion in water for 30 seconds and drying, 8
Water vapor generated from hot water of 0 ° C. was applied to determine the antifogging property.

：: No fogging X: At least a part of fogging (6) Anti-blocking property Diameter: 1 so that the surface-treated film face is inside
Molded into cylindrical containers of three sizes of 00 mm, depths of 10 mm, 20 mm and 30 mm, the obtained 20 molded products were overlapped and pressed by hand from above and below to bring the molded products into close contact with each other. The peelability when taking out the stacked molded products one by one by hand was examined.

：: Smooth peeling possible Δ: Slightly poor peelability ×: Difficult to peel off The corona discharge treatment of the sheets used in Examples and Comparative Examples was performed as follows. That is, JIS K-
Surface tension measured according to 6768 is 33 dyn / c
m biaxially oriented polystyrene sheet (250 μm thick)
To a corona discharge treatment machine (AB708-1 manufactured by PILLAR)
8, a capacity of 1.5 KW) between the electrodes to obtain a biaxially stretched polystyrene sheet having a surface tension of 58 dyn / cm.

Examples 1 to 4 Sucrose fatty acid esters in which the main component of the fatty acid is lauric acid (Rikemar A, manufactured by Riken Vitamin Co., Ltd.)
And dimethylpolysiloxane silicone emulsion (Shin-Etsu Silicone KM89, manufactured by Shin-Etsu Chemical Co., Ltd.)
3 ") and a polysaccharide were combined to prepare an aqueous surface treating agent in the ratio (parts by weight) shown in Table 1.

[0107] It should be noted that, as a polysaccharide, white color dextrin (product of Sigma Chemical Co., Ltd., trade name "TypeIIwhite po
wder ") (Example 1 ), gum arabic (Wako Pure Chemical Industries, Ltd.) (Examples 2 and 4 ), and soluble starch (Wako Pure Chemical Industries, Ltd.) (Example 3 ). Further, only water was used as a solvent for the surface treatment agent.

These surface treating agents were applied to a biaxially stretched polystyrene sheet having a surface tension of 58 dyn / cm by corona discharge treatment to form coating films having the coating amounts shown in Table 1 (after drying).

Comparative Examples 1 to 5 The sucrose fatty acid ester used in the examples, the silicone emulsion of dimethylpolysiloxane, and the soluble starch were combined to prepare an aqueous surface treating agent in the ratio (parts by weight) shown in Table 2. .

The obtained surface treating agent was applied to a biaxially stretched polystyrene sheet subjected to corona discharge treatment in the same manner as in Example 1 to form a coating film having the coating amount (after drying) shown in Table 2.

Comparative Example 6 An aqueous surface treating agent containing an ethylene oxide adduct of sorbitan monooleate and a methylpolysiloxane elastomer in the proportions (parts by weight) shown in Table 2 (JP-A-53-1)
15781).

The obtained surface treating agent was applied to a biaxially stretched polystyrene sheet subjected to corona discharge treatment in the same manner as in Example 1 to form a coating film having the coating amount (after drying) shown in Table 1.

Then, the above Examples 1 to 4 and Comparative Examples 1 to
The properties of the coated film obtained in No. 6 were evaluated according to the above evaluation method. Table 2 shows the results.

[0114]

[Table 1]

[0115]

[Table 2] From Tables 1 and 2, the styrene-based polymer film treated with the surface treatment agent containing sucrose fatty acid ester, silicone emulsion and polysaccharide was subjected to deep drawing.
High appearance, anti-fogging property and anti-blocking property.

On the other hand, the polymer films treated with the surface treatment agents of Comparative Examples 1 to 5 which did not contain any of the components of sucrose fatty acid ester, silicone emulsion and polysaccharide had appearance, anti-fogging properties and anti-blocking properties. Not only is the property poor, but the coating film is cut off by the molding process, and the antifogging property is reduced. In addition, in the surface treatment agent of Comparative Example 6 containing no polysaccharide and using a surfactant instead of the sucrose fatty acid ester, the surfactant was leaked out by water, the antifogging property was not maintained, and the coating film was formed by molding. Are separated, and the antifogging property is further reduced.

Examples 5 to 9 Sucrose fatty acid esters in which the main component of the fatty acid is lauric acid (Rikemar A, manufactured by Riken Vitamin Co., Ltd.)
And dimethylpolysiloxane silicone emulsion (Shin-Etsu Silicone KM89, manufactured by Shin-Etsu Chemical Co., Ltd.)
3 ") and a hydrophilic polymer were combined to prepare an aqueous surface treating agent in the ratio (parts by weight) shown in Table 3.

As the hydrophilic polymer, sodium polyacrylate having a different degree of polymerization (manufactured by Wako Pure Chemical Industries, Ltd.)
(Examples 5 to 8 ) and polyvinylpyrrolidone (manufactured by Aldrich) (Example 9 ) were used. Further, only water was used as a solvent for the surface treatment agent.

These surface treating agents were applied to the same biaxially oriented polystyrene sheet as in Example 1 to form coating films having the coating amounts (after drying) shown in Table 3.

Comparative Example 7 An aqueous surface treating agent having the ratio (parts by weight) shown in Table 3 was prepared by combining the sucrose fatty acid ester used in Example 1 and the sodium polyacrylate used in Example 5. In the same manner as in Example 1, it was applied to a biaxially stretched polystyrene sheet subjected to a corona discharge treatment to form a coating film having the coating amount (after drying) shown in Table 3.

Comparative Example 8 Using sucrose fatty acid ester and silicone emulsion used in Example 1 and polyvinyl alcohol, Table 3
The aqueous surface treating agent in the ratio (parts by weight) shown in Table 3 was prepared and applied to the biaxially stretched polystyrene sheet subjected to the corona discharge treatment in the same manner as in Example 1. The coating amount (after drying) shown in Table 3 was applied. Was formed.

Then, Examples 5 to 9 and Comparative Examples 7,
The characteristics of the coated film obtained in No. 8 were evaluated according to the evaluation method described above. Table 3 shows the results.

[0123]

[Table 3] From Table 3, as compared with the coated films of Comparative Examples 7 and 8, the styrene-based polymer film treated with the surface treatment agent containing sucrose fatty acid ester, silicone emulsion and hydrophilic polymer was subjected to deep drawing. Well, appearance,
High antifogging and anti-blocking properties.

Claims (9)

(57) [Claims] 1. A sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer (however,
(Excluding polyvinyl alcohol). 2. A silicone emulsion having a solid content of 20 to 1 based on 100 parts by weight of sucrose fatty acid ester.
2. The surface treating agent according to claim 1, comprising 000 parts by weight and 10 to 1000 parts by weight of a polysaccharide. 3. A silicone emulsion having a solid content of 20 to 1 based on 100 parts by weight of sucrose fatty acid ester.
The surface treatment agent according to claim 1, wherein the surface treatment agent comprises 000 parts by weight and 10 to 100 parts by weight of a hydrophilic polymer. 4. The surface treating agent according to claim 1, wherein the main component of the fatty acid in the sucrose fatty acid ester is lauric acid. 5. A coating layer comprising a sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer (excluding polyvinyl alcohol) is formed on at least one surface of the polymer film. Coated polymer film. 6. At least one surface of the polymer film has a sucrose fatty acid ester content of 10 to 50 mg / m ² , and a solid content of 10 to 100 mg of a silicone emulsion.
/ M ^2, coated polymeric film according to claim 5, wherein the coating layer containing the polysaccharide in an amount of 5 to 100 mg / m ² is formed. 7. On at least one surface of the polymer film, 10 to 50 mg / m ² of a sucrose fatty acid ester and 10 to 100 mg of a silicone emulsion as a solid content.
/ M ^2, coated polymeric film according to claim 5, wherein the coating layer containing a hydrophilic polymer in a ratio of 1 to 50 mg / m ² is formed. 8. The coated polymer film according to claim 5, wherein the polymer film is a styrene-based polymer film. 9. A surface treatment agent containing a sucrose fatty acid ester, a silicone emulsion, a polysaccharide and / or a hydrophilic polymer (excluding polyvinyl alcohol) is applied to at least one surface of the polymer film. A method for producing a coated polymer film.