JP2018012795A - Nonaqueous oligomer bleeding-preventing agent for polyester film, method for producing laminated polyester film, and method for preventing oligomer bleeding of polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oligomer bleeding-preventing agent capable of suppressing deposition of a polyester oligomer on a film surface during high-temperature and long-time heating.SOLUTION: The present invention relates to the nonaqueous oligomer bleeding-preventing agent for a polyester film, which contains: an acrylic copolymer (A) comprising a reaction component containing a hydroxyl group-containing (meth)acrylate (a1) and an alkyl (meth)acrylate (a2); a polyisocyanate (B) having at least three isocyanate groups; and an organic solvent (C). The molar ratio [NCO/OH] of isocyanate groups contained in the component (B) to hydroxyl groups contained in the component (A) is 0.2-5.SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous oligomer bleed inhibitor for polyester film, a method for producing a laminated polyester film, and a method for preventing oligomer bleed of a polyester film.

  Polyester films are widely used in magnetic tapes, capacitors, packaging, plate making and electrical insulation applications because they are excellent in transparency, dimensional stability, mechanical properties, chemical resistance, and the like. Recently, it has been widely used as a base material for transparent conductive laminates used for optical film applications requiring high transparency, particularly touch panels.

  The transparent conductive laminate is laminated with an ITO (indium tin oxide) film by sputtering directly on the polyester film surface or via an anchor layer. Thereafter, heat treatment is performed at a high temperature of about 150 ° C. for crystallization of ITO.

  By the way, when a polyester film is heated at a high temperature for a long time, oligomers contained in the film (low molecular weight components of polyester, particularly ester cyclic trimers) precipitate on the film surface (hereinafter also referred to as “bleed”). In addition, a decrease in visibility due to whitening of the film appearance, defects in post-processing, contamination of the process and members, and the like occur.

  As a technique for preventing bleeding of a polyester oligomer, a technique in which an oligomer sealing layer made of a two-component reaction resin of a polyester resin and a polyisocyanate is laminated on the surface of a polyester film is known (Patent Document 1). This film exhibits a certain bleed prevention effect, but when heated for a long time, the effect was insufficient.

JP-A-6-328646

  The main object of the present invention is to provide an oligomer bleed inhibitor capable of suppressing the precipitation of the polyester oligomer on the film surface during heating at a high temperature for a long time.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by a bleed inhibitor containing a predetermined acrylic copolymer and polyisocyanate. That is, the present invention relates to the following non-aqueous oligomer bleed inhibitor, a method for producing a laminated polyester film, and a method for preventing oligomer bleed of a polyester film.

1. An acrylic copolymer (A) comprising a reaction component containing a hydroxyl group-containing (meth) acrylate (a1) and an alkyl (meth) acrylate (a2), a polyisocyanate (B) having at least three isocyanate groups, and an organic solvent (C) Furthermore, the non-aqueous oligomer bleed inhibitor for polyester films in which the molar ratio [NCO / OH] of the hydroxyl group contained in the component (A) and the isocyanate group contained in the component (B) is 0.2 to 5.

2. (A) The non-aqueous oligomer bleed inhibitor according to item 1 above, wherein the component has a glass transition temperature of 50 ° C to 120 ° C.

3. (A) The non-aqueous oligomer bleed inhibitor according to Item 1 or 2, wherein the hydroxyl group content of the component is 0.6 to 6 mmol / g.

4). (A) The non-aqueous oligomer bleed inhibitor according to any one of Items 1 to 3, wherein the component has a weight average molecular weight of 5,000 to 100,000.

5. The non-aqueous oligomer bleed inhibitor according to any one of Items 1 to 4, wherein the component (B) comprises an aromatic polyisocyanate (b1).

6). (B) The non-aqueous oligomer bleeding agent according to any one of Items 1 to 5, wherein the isocyanate group content of the component is 1 to 8 mmol / g.

7). (C) The non-aqueous oligomer bleed inhibitor according to 1 to 6, wherein the component includes at least one selected from the group consisting of ketone-based, ester-based and aromatic solvents.

8). A method for producing a laminated polyester film, wherein the non-aqueous oligomer bleed inhibitor according to any one of Items 1 to 7 is applied to at least one surface of a polyester film and heated.

9. Item 9. The method for producing a laminated polyester film according to Item 8, wherein the polyester film is a polyethylene terephthalate film or polyethylene-2,6-naphthalate.

10. A method for preventing oligomer bleeding of a polyester film, comprising applying the non-aqueous oligomer bleeding inhibitor according to any one of Items 1 to 7 to at least one surface of a polyester film.

  Since the non-aqueous oligomer bleed inhibitor of the present invention can suppress the precipitation of the polyester oligomer on the film surface during heating at a high temperature for a long time, it can maintain high transparency even after heating.

  The non-aqueous oligomer bleed inhibitor for polyester film of the present invention (hereinafter referred to as non-aqueous oligomer bleed inhibitor) is a hydroxyl group-containing (meth) acrylate (a1) (hereinafter also referred to as component (a1)) and an alkyl (meth) acrylate. Acrylic copolymer (A) (hereinafter also referred to as (A) component) which is a reaction product of (a2) (hereinafter also referred to as (a2) component), and (B) polyfunctional isocyanate compound (B) (hereinafter referred to as ( B) component) and organic solvent (C) (hereinafter also referred to as component (C)).

  As the component (a1), various known compounds can be used without particular limitation as long as they are compounds having a (meth) acryloyl group and at least one hydroxyalkyl group in the molecule. Specifically, for example, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-methacrylic acid 3- Hydroxybutyl, 4-hydroxybutyl (meth) acrylate, hydroxycyclohexyl (meth) acrylate, 4- (hydroxymethyl) cyclohexylmethyl (meth) acrylate, hydroxyphenyl (meth) acrylate, N- (2-hydroxyethyl) ) Hydroxy (meth) acrylates such as acrylamide and N- (1-methyl-2-hydroxyethyl) acrylamide, and the like, and two or more of these may be combined.

  As the component (a2), various known compounds can be used without particular limitation as long as they have a (meth) acryloyl group and an alkyl ester group in the molecule. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, (meth) acrylic Tert-butyl acid, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexadecyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, icosyl (meth) acrylate, ( Examples include docosyl acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, and the like, which can be used in combination of two or more. .

  The reaction component of the component (A) further includes at least one monomer (a3) selected from the group consisting of an aromatic vinyl monomer, (meth) acrylonitrile, and (meth) acrylamide (hereinafter referred to as the component (a3). May also be included).

  As the aromatic vinyl monomer, various known monomers can be used without particular limitation as long as they are compounds having a vinyl group and an aromatic ring in the molecule. Specifically, for example, styrenes such as styrene, α-methylstyrene, t-butylstyrene, aryl such as phenyl (meth) acrylate, benzyl (meth) acrylate, 4-methylbenzyl (meth) acrylate (Meth) acrylates and the like can be mentioned, and two or more of these can be combined.

  The amount of each component used (% by weight) is not particularly limited, but is usually as follows from the viewpoint of preventing bleeding of the oligomer.

<Aspect not using (a3) component>
(A1) component: about 5 to 80% by weight, preferably about 10 to 60% by weight (a2) component: about 20 to 95% by weight, preferably about 40 to 90% by weight

<Aspect using (a3) component>
(A1) component: about 5 to 80% by weight, preferably about 10 to 60% by weight (a2) component: about 5 to 90% by weight, preferably about 25 to 80% by weight (a3) component: 5 to 15% by weight Degree, preferably about 10 to 15% by weight

  Examples of the reaction component (A) include vinyl monomers other than the components (a1) to (a3) (hereinafter referred to as component (a4)) such as 2,4,4-trimethyl-1-pentene, 3- Α-olefins such as methyl-1-butene, 3-methyl-1-pentene, 1-hexene, vinylcyclohexane, 2-methylvinylcyclohexane, (meth) allyl alcohol, 4-penten-1-ol, 1-methyl Unsaturated alcohols such as -3-buten-1-ol and 5-hexen-1-ol, (meth) acrylic acid, 3-butenoic acid, 4-pentenoic acid, 5-hexenoic acid, fumaric acid, (anhydrous ) Unsaturated carboxylic acids such as maleic acid and itaconic acid may be included. Moreover, these can combine 2 or more types. Moreover, the usage-amount of (a4) component is although it does not specifically limit, Usually, it is less than 20 weight% with respect to the sum total of (a1) component, (a2) component, and (a3) component.

  The component (A) can be produced by various known methods. Specifically, for example, by subjecting each of the above components to a copolymerization reaction in the absence of a solvent or in an appropriate organic solvent, usually in the presence of a radical polymerization initiator at about 80 to 180 ° C. for about 1 to 10 hours. Can be obtained. Examples of the radical polymerization initiator include hydrogen peroxide, ammonium persulfate, potassium persulfate, t-butyl peroxybenzoate, dicumyl peroxide, lauryl peroxide, 2,2′-azobisisobutyronitrile, dimethyl-2 , 2′-azobisisobutyrate and the like. In addition, although the usage-amount is not specifically limited, Usually, it is the range used as about 0.1 to 2 weight% with respect to the total weight of the reaction component of (A) component. Examples of the organic solvent include those described below.

  The physical properties of the component (A) are not particularly limited, but from the viewpoint of preventing oligomer bleed, the hydroxyl group content is usually about 0.6 to 6 mmol / g, preferably about 0.7 to 4 mmol / g in terms of solid content. More preferably, it is about 0.8-3 mmol / g. The hydroxyl group content is a value obtained by dividing the hydroxyl value (mg KOH / g) measured according to JIS K-0070 by the molecular weight of potassium hydroxide (Mw. 56.1). From the same point as described above, the glass transition temperature is about 50 to 120 ° C, preferably about 60 to 100 ° C, more preferably about 70 to 90 ° C. Although the weight average molecular weight (polystyrene conversion value in the gel permeation chromatography method) is not particularly limited, it is usually about 5000 to 100,000, preferably about 10,000 to 75000, more preferably about 20000 to 60000 from the same point as described above.

  The component (B) is not particularly limited as long as it is a polyisocyanate having at least three isocyanate groups in the molecule, and various known ones can be used. (B) A component gives a crosslinked structure to an oligomer bleed prevention layer by urethanation with (A) component.

  Specific examples of the component (B) include aromatic polyisocyanate (b1) (hereinafter referred to as component (b1)), aliphatic polyisocyanate (b2) (hereinafter referred to as component (b2)), and alicyclic system. And polyisocyanate (b3) (hereinafter referred to as component (b3)). Two or more of these can be combined.

  Specific examples of the component (b1) include biuret, isocyanurate and adduct derivatives (b1-1) of aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate (hereinafter referred to as (b1-1). ) Component), (b1-1) reaction product of component and diol compound (b1-2) (hereinafter referred to as (b1-2) component), toluene-2,4,6-triisocyanate, triphenylmethanetri Examples thereof include aromatic triisocyanate compounds (b1-3) (hereinafter referred to as (b1-3) component) such as isocyanate and tris (isocyanatephenyl) thiophosphate. Two or more of these can be combined.

  The diol compound is not particularly limited. Specific examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, neopentyl glycol, 1,6-hexanediol, and octane. Examples thereof include diol, dipropylene glycol, polyethylene glycol, and polypropylene glycol. Two or more of these can be combined (hereinafter, the same applies when referred to as a diol compound).

  Specific examples of the component (b2) include biuret, isocyanurate and adduct derivative (b2-1) of aliphatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate (hereinafter referred to as (b2) -1) component), (b2-1) reaction product of component and diol compound (b2-2) (hereinafter referred to as (b2-2) component), 1,6,11-undecane triisocyanate and 1,3 Aliphatic triisocyanate compounds (b2-3) (hereinafter referred to as (b2-3) component) such as 1,6-hexamethylene triisocyanate. Two or more of these can be combined.

  Specific examples of the component (b3) include biuret, isocyanurate and adduct of alicyclic diisocyanate compounds such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylene diisocyanate and hydrogenated tolylene diisocyanate. Body derivative (b3-1) (hereinafter referred to as (b3-1) component), reaction product of (b3-1) component and diol compound (b3-2) (hereinafter referred to as (b3-2) component), And alicyclic triisocyanate compounds (b3-3) (hereinafter referred to as (b3-3) component) such as bicycloheptane triisocyanate. Two or more of these can be combined.

  Here, each biuret body of the component (b1-1), the component (b2-1) and the component (b3-1) is represented by the following structural formula.

(In the formula, R ¹ represents a residue of a diisocyanate compound.)

  Moreover, each isocyanurate body of the said (b1-1) component, (b2-1) component, and (b3-1) component is represented by the following structural formula.

(In the formula, R ² represents a residue of a diisocyanate compound.)

  Moreover, each adduct body of the said (b1-1) component, (b2-1) component, and (b3-1) component is represented by the following structural formula.

(In the formula, R ³ represents an alkyl group having 1 to ³ carbon atoms or a functional group represented by OCN—R ⁴ —HN—C (═O) —O—CH ₂ —, and R ⁴ represents a residue of a diisocyanate compound. Represents.)

  The components (b1-2), (b2-2), and (b3-2) can all be produced by various known methods. Specifically, the molar ratio [NCO ′ / OH ′] of the isocyanate group (NCO ′) and the latter hydroxyl group (OH ′) of the isocyanate component and the diol compound is usually about 5 to 20, preferably In the range which becomes about 10-20, it can obtain by making urethanation reaction normally under 40-80 degreeC for about 1 to 5 hours.

  Among these, from the viewpoint of preventing bleeding of the oligomer, the component (b1) is preferable, the component (b1-1) and the component (b1-2) are more preferable, and isocyanurate body, adduct body or aromatic diisocyanate compound. A reaction product with the diol compound is particularly preferred.

  (B) Although the physical property of a component is not specifically limited, From the point of prevention of bleeding of an oligomer, isocyanate group content is about 1-8 mmol / g normally by solid content, Preferably it is about 2-7 mmol / g, More preferably It is about 3-6 mmol / g. The isocyanate group content is a value measured according to JIS K-7301.

  The content ratio of the component (A) and the component (B) is not particularly limited, but is usually a molar ratio [NCO / OH] of the hydroxyl group contained in the component (A) and the isocyanate group contained in the component (B). It is about 0.2-5, preferably about 0.3-3, more preferably about 0.5-2. When the molar ratio is less than 0.2, it is difficult to suppress oligomer bleed, and when it exceeds 5, the adhesion to the film tends to decrease.

  Specific examples of the component (C) include, for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, and acetyl acetone; ester solvents such as ethyl acetate and butyl acetate; aromatic hydrocarbon solvents such as toluene and xylene; Examples thereof include alcohol solvents such as ethanol and isopropanol, and two or more kinds can be used in combination. Among these, at least one selected from the group consisting of a ketone solvent, an ester solvent and an aromatic solvent is preferable from the viewpoint of the pot life of the non-aqueous oligomer bleed inhibitor, and a ketone solvent is more preferable from the same point. In addition, when water is used in combination with the component (C), water easily reacts with the component (B), and when formed into a coating film, the adhesiveness to the film tends to decrease, which is not preferable.

  Although the usage-amount of (C) component is not specifically limited, From the point of coating property, the solid content concentration of the non-aqueous oligomer bleed inhibitor of this invention is about 1 to 50 weight% normally, Preferably it is 5 to 30 weight. It is the range which becomes about%.

  The non-aqueous oligomer bleed inhibitor of the present invention may contain various known curing catalysts (D) (hereinafter referred to as “component (D)”) as necessary. Specific examples of the component (D) include, for example, tertiary amine compounds such as triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU); dibutyltin dichloride, dibutyltin Oxide, Dibutyltin dibromide, Dibutyltin dimaleate, Dibutyltin dilaurate, Dibutyltin diacetate, Dibutyltin sulfide, Tributyltin sulfide, Tributyltin oxide, Tributyltin acetate, Triethyltin ethoxide, Tributyltin ethoxide, Dioctyltin oxide, Dioctyltin Tin compounds such as dilaurate, dioctyltin diversate, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate; dibutyltitanium dichloride, tetra Titanium compounds such as til titanate and butoxy titanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate and lead naphthenate; iron 2-ethylhexanoate, iron acetylacetonate, etc. Iron-based compounds; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; bismuth-based compounds such as bismuth 2-ethylhexanoate and bismuth naphthenate, and the like.

  Although the usage-amount of (D) component is not specifically limited, Usually, 0.01-5 mass% (solid content conversion) with respect to a total of 100 mass parts (solid content conversion) of (A) component and (B) component. ) As long as it is within a range.

  Although it does not specifically limit as a preparation method of the non-aqueous oligomer bleed inhibitor of this invention, For example, (A) component, (B) component and (C) component, (D) component is known variously as needed. It can be mixed by means. The mixing order is not particularly limited.

  In the non-aqueous oligomer bleed inhibitor of the present invention, if necessary, a binder resin other than the component (A) (urethane resin, polyester resin, epoxy resin, alkyd resin, etc.), anti-slip agent, antiseptic agent, rust inhibitor, A pH adjuster, antioxidant, pigment, dye, lubricant, leveling agent, anti-blocking agent, antifoaming agent and the like may be included.

  The method for producing a laminated polyester film according to the present invention is characterized in that the non-aqueous oligomer bleed inhibitor of the present invention is applied to at least one surface of a polyester film and heated.

  The polyester film of the substrate is not particularly limited, and various known materials can be used. Specific examples include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polypropylene-2,6-naphthalate, and the like. Among these, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferable because the base film has high transparency. Also, the thickness of the polyester film is not particularly limited, and is usually about 10 to 188 μm, preferably about 25 to 100 μm.

  If necessary, the polyester film may be subjected to easy adhesion treatment, corona treatment, plasma treatment or the like on the film surface in order to improve the adhesion between the film and the non-aqueous oligomer bleed inhibitor.

It does not specifically limit as a coating means in the manufacturing method of the laminated polyester film of this invention, Various well-known things are applicable. Examples thereof include a roll coater, a reverse roll coater, a gravure coater, a knife coater, and a bar coater. Also, the coating amount is not particularly limited, and it may be usually in the range where the mass after drying is about 0.05 to ² g / m ² , preferably 0.1 to 1 g / m ² .

  The heating conditions in the production method are also not particularly limited, and are usually about 90 seconds to 130 ° C. and about 30 seconds to 2 minutes.

  The obtained laminated polyester film may be subjected to curing treatment or may be turned down as necessary. The treatment conditions are not particularly limited, but are about 20 to 50 ° C. for about 1 to 24 hours. The treatment improves the solvent resistance of the cured film.

  The polyester film oligomer bleed prevention method of the present invention is characterized in that the non-aqueous oligomer bleed inhibitor is applied to at least one surface of a polyester film.

  The polyester film of the substrate, the coating means and the heating conditions are as described above.

  Hereinafter, although the present invention will be described in detail through examples and comparative examples, the scope of the present invention is not limited thereby. Moreover, in each Example and a comparative example, a part or% is a mass reference | standard.

<Glass transition temperature>
The glass transition temperature was measured using a commercially available measuring instrument (product name “DSC8230B”, manufactured by Rigaku Corporation).
<Weight average molecular weight>
The weight average molecular weight was measured using a commercially available gel permeation chromatography instrument (product name “HLC-8220GPC”, manufactured by Tosoh Corporation). In addition, a measured value is shown by a polystyrene conversion value.
<Hydroxyl content>
The hydroxyl group content is a value obtained by dividing the hydroxyl value (mg KOH / g) measured according to JIS K-0070 by the molecular weight of potassium hydroxide (Mw. 56.1).
(Formula 1) Hydroxyl content (mmol / g) = (Hydroxyl value) / (Molecular weight of potassium hydroxide)
<Isocyanate group content>
The isocyanate group content was measured according to JIS K-7301.

Production Example 1 <Synthesis of Acrylic Copolymer (A-1)>
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen introduction tube, 192.0 parts of methyl methacrylate, 7.2 parts of normal butyl acrylate, and 2-hydroxyethyl acrylate 40.8 And 360 parts of methyl ethyl ketone were charged, and the reaction system was set to 80 ° C. Next, 1.2 parts of azobisisobutyronitrile was charged and kept at 80 ° C. for 5 hours. Next, 2.4 parts of azobisisobutyronitrile was charged, and the reaction system was further kept at the same temperature for 4 hours. Thereafter, the reaction system was cooled to room temperature, whereby a solution of acrylic copolymer (A-1) having a glass transition temperature of 70 ° C., a hydroxyl group content of 1.43 mmol / g (solid content), and a weight average molecular weight of 50000 (solid content concentration of 30 %).

Production Example 2 <Synthesis of Acrylic Copolymer (A-2)>
In the same reaction vessel as in Production Example 1, 177.6 parts of methyl methacrylate, 20.9 parts of normal butyl acrylate, 17.5 parts of 2-hydroxyethyl acrylate, 24.0 parts of styrene, and 360.0 methyl ethyl ketone The reaction system was set to 80 ° C. Next, 1.2 parts of azobisisobutyronitrile was charged and kept at 80 ° C. for 5 hours. Next, 2.4 parts of azobisisobutyronitrile was charged, and the reaction system was further kept at the same temperature for 4 hours. Thereafter, the reaction system was cooled to room temperature, whereby a solution of acrylic copolymer (A-2) having a glass transition temperature of 70 ° C., a hydroxyl group content of 0.62 mmol / g (solid content), and a weight average molecular weight of 45000 (solid content concentration of 30 %).

Production Example 3 (Synthesis of polyisocyanate (B-3))
In a reaction vessel similar to Production Example 1, 445.5 parts of isocyanurate of tolylene diisocyanate (product name “Coronate 2037”, manufactured by Tosoh Corporation, solid content concentration 50%), 1,6-hexanediol 5. 0 part and 308.6 parts of methyl ethyl ketone were charged, and urethanization reaction was carried out at 60 ° C. for 3 hours. Thereafter, by cooling to room temperature, a solution (solid content concentration 30%) of polyisocyanate (B-3) having an isocyanate group content of 3.3 mmol / g (solid content) was obtained.

<Preparation of non-aqueous oligomer bleed inhibitor>
Example 1
(A) 333.3 parts (A-1) as a component (solid content conversion: 100 parts by weight), and 74.9 parts of Coronate 2037 (manufactured by Tosoh Corporation, solid content concentration 50%) as the component (B) ( 37.5 parts in terms of solid content) and 346.3 parts of methyl ethyl ketone were mixed well to prepare a non-aqueous oligomer bleed inhibitor having a solid content concentration of 8.8%.

Examples 2-8, Comparative Examples 1-3
A non-aqueous oligomer bleed inhibitor was prepared in the same manner as in Example 1, except that the type or amount used was as shown in Table 1.

[Preparation of test film]
Using a bar coater, nonaqueous oligomeric bleeding inhibitor PET film of Example 1 as film thickness when dry is 0.3 g / ^{m 2} (Cosmoshine A 4300 50 [mu] m thick haze: 0.9 Toyobo (strain ) Made) and was blown with a dryer for 10 seconds. Next, the non-aqueous oligomer bleed inhibitor of Example 1 was applied to the opposite surface and dried in a forward air drier (120 ° C., 1 minute) to prepare a test film. Test films were prepared in the same manner for the non-aqueous oligomer bleed inhibitors of Examples 2 to 8 and Comparative Examples 1 to 3.

[Transparency before heating]
The haze value of the test film was measured according to JIS K-7136 using a haze meter “HM-150” (Murakami Color Research Laboratory). An uncoated PET film was also evaluated as Comparative Example 4.

[Transparency after heating]
After the test film was heated at a temperature of 150 ° C. for 3 hours, haze was measured by the same method as described above. An uncoated PET film was also evaluated as Comparative Example 4.

* The amount of each component used is indicated as a solid content conversion value.

(B-1) Coronate 2037: (isocyanurate of tolylene diisocyanate, isocyanate group content 3.8 mmol / g (solid content), manufactured by Tosoh Corporation, solid content concentration 50%)
(B-2) Coronate HX: (isocyanurate of hexamethylene diisocyanate, isocyanate group content 5.1 mmol / g (solid content), manufactured by Tosoh Corporation, solid content concentration 100%)
(B-3) Polyisocyanate of Production Example 3 (isocyanate group content 3.3 mmol / g (solid content), solid content concentration 30%)
(F-1) Kuraray polyol P-1010 (polyester polyol, hydroxyl group content 2.0 mmol / g (solid content), manufactured by Kuraray Co., Ltd.)

Claims (10)

An acrylic copolymer (A) comprising a reaction component containing a hydroxyl group-containing (meth) acrylate (a1) and an alkyl (meth) acrylate (a2), a polyisocyanate (B) having at least three isocyanate groups, and an organic solvent (C) Furthermore, the non-aqueous oligomer bleed inhibitor for polyester films in which the molar ratio [NCO / OH] of the hydroxyl group contained in the component (A) and the isocyanate group contained in the component (B) is 0.2 to 5. The non-aqueous oligomer bleed inhibitor according to claim 1, wherein the glass transition temperature of component (A) is from 50C to 120C. (A) Hydroxyl content of a component is 0.6-6 mmol / g, The non-aqueous oligomer bleed inhibitor of Claim 1 or 2. The weight average molecular weight of (A) component is 5000-100000, The non-aqueous oligomer bleed inhibitor in any one of Claims 1-3. The non-aqueous oligomer bleed inhibitor according to claim 1, wherein the component (B) contains an aromatic polyisocyanate (b1). (B) The isocyanate group content of a component is 1-8 mmol / g, The nonaqueous oligomer bleeding agent in any one of Claims 1-5. The non-aqueous oligomer bleed inhibitor according to any one of claims 1 to 6, wherein the component (C) contains at least one selected from the group consisting of ketone-based, ester-based and aromatic solvents. A method for producing a laminated polyester film, wherein the non-aqueous oligomer bleed inhibitor according to claim 1 is applied to at least one surface of a polyester film and heated. The method for producing a laminated polyester film according to claim 8, wherein the polyester film is polyethylene terephthalate or polyethylene-2,6-naphthalate.   A method for preventing oligomer bleeding of a polyester film, comprising applying the non-aqueous oligomer bleeding inhibitor according to any one of claims 1 to 7 to at least one surface of a polyester film.