JP4613486B2 - Polyester resin composition for coating - Google Patents

Description

  The present invention relates to a coating composition comprising a polyester resin as a main component, and more specifically, has excellent adhesion to plastic film substrates such as polyethylene terephthalate (hereinafter referred to as PET) and metals, and has heat resistance and processability. The present invention relates to a good polyester resin composition for coating.

  Recently, PET has been widely used in the molding direction of sheets and bottles, and accordingly, there has been an increasing demand for surface modification of molded products, lamination between PET or other resins, printing on the molded products, and the like. Usually, in applications such as printing on PET composite films and PET containers, adhesion to PET surface adhesives, adhesion to ink, and deposition on metals such as aluminum to improve gas barrier properties Surface treatment is performed because it is necessary to improve adhesion (hereinafter collectively referred to as adhesion). For example, (1) a method of activating the PET surface by corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, etc., (2) a method of treating the PET surface with various chemicals, (3) a primer layer on the PET surface, There is a method of providing a coating layer. However, the method (1) improves the initial adhesion, but decreases with time. In the method (2), handling of chemical treatment procedures and the like is complicated. In the method (3), water-based or solvent-based methods are conventionally used, the former being non-polluting, and the latter having the advantage of good drying properties after coating. However, there is still a need for improvement in terms of heat resistance. That is, when the coated PET substrate or the like is stored in the summer, heat resistance (blocking resistance) of at least 60 to 80 ° C. is necessary so that the coating surface does not cause blocking.

  In addition, when plastic films such as PET are used as the packaging material constituting the packaging bag, a plastic film provided with a metal vapor deposition film such as aluminum is laminated in order to provide gas barrier properties, light shielding properties, etc. Laminated bodies are widely used. However, when such a laminate is made into a bag shape and heat-sealed, there is a problem that cracks or the like occur in a metal vapor deposition film such as aluminum in the heat-sealed portion and the vicinity thereof, and the gas barrier property is lowered. (For example, refer to Patent Document 1).

  Therefore, a primer coat that increases the tight adhesion with the metal thin film layer, strengthens the tight adhesion strength, prevents the delamination, etc., and improves the gas barrier property, moisture proof property, light shielding property, etc. by the metal thin film layer. It is necessary to develop a new layer.

JP2003-251734 (Claims)

  The present invention relates to a coating composition comprising a polyester resin as a main component. More specifically, the present invention has excellent adhesion to a plastic film substrate such as polyethylene terephthalate (PET) or metal, and has good heat resistance and workability. The present invention relates to a polyester resin composition for coating.

  As a result of intensive studies to achieve the above problems, the present inventors have invented the following polyester resin compositions for coating.

(1) For coating containing a polyester resin (A) and an acrylic resin-based reactive compound (B) containing two or more glycidyl groups and / or isocyanate groups per molecule and having a weight average molecular weight of 200 to 500,000 Polyester resin composition.

(2) The reactive compound (B) is (X) 20 to 99% by weight of vinyl aromatic monomer and (Y) 1.0 to 80% by weight of hydroxyalkyl (meth) acrylate or glycidylalkyl (meth) acrylate, And (Z) the polyester resin composition for coating according to (1), comprising 1.0 to 70% by weight of alkyl (meth) acrylate.

(3) The polyester resin composition for coating according to (1) or (2), wherein the polyester resin (A) is amorphous.

(4) The polyester resin (A) has a polyfunctional compound unit having three or more carboxyl groups, hydroxyl groups or ester-forming groups thereof in the molecule as the acid component and / or the glycol component of 0.001 to 5 in the polyester. The polyester resin composition for coating according to any one of (1) to (3), which is contained in mol%.

(5) The polyester resin (A) contains an aromatic dicarboxylic acid having 8 to 14 carbon atoms and an aliphatic or alicyclic glycol having 2 to 10 carbon atoms in an amount of 50 mol% or more of each of the acid component and the glycol component. The polyester resin composition for coating according to any one of (1) to (4).

(6) The polyester resin composition for coating according to (5), wherein the aromatic dicarboxylic acid having 8 to 14 carbon atoms is terephthalic acid and / or isophthalic acid.

(7) The aliphatic or alicyclic glycol having 2 to 10 carbon atoms is ethylene glycol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, 1,2-propanediol, 1,3-propanediol and 2-methyl-1, The polyester-based resin composition for coating according to (5), which is at least one selected from the group consisting of 3-propanediol.

(8) The polyester resin composition for coating according to any one of (1) to (7), wherein the glass transition temperature of the polyester resin (A) is 40 ° C. or higher and lower than 120 ° C.

(9) The polyester resin composition for coating according to any one of (1) to (8), wherein the reduced viscosity of the polyester resin (A) is 0.4 dl / g or more.

(10) In the polyester resin composition for coating according to any one of (1) to (9), the blending ratio of the solid matter and the mixed solvent is 5/95 to 50/50 (weight ratio). A polyester resin composition for coating.

  The coating composition comprising the polyester resin of the present invention as a main component is excellent in adhesiveness to plastic film substrates such as polyethylene terephthalate (PET) and metals, and has good heat resistance and workability. It is useful as a coating agent for paints, anchor coating materials and various binders.

  Any polyester resin (A) can be used as long as it is composed of a dicarboxylic acid component and a glycol component.

  The polyester resin used in the present invention is preferably amorphous. If the polyester resin is amorphous, the product can be made transparent because there is no whitening derived from crystals. Note that the term “amorphous” as used herein means that the temperature was raised from −100 ° C. to 300 ° C. at 20 ° C./min using a differential scanning calorimeter (DSC), and then was lowered to −100 ° C. at 50 ° C./min. Subsequently, in the two temperature rising processes in which the temperature is raised from −100 ° C. to 300 ° C. at 20 ° C./min, neither indicates a melting peak. On the other hand, crystallinity refers to those showing a clear melting peak in either temperature rising process.

  The polyester resin used in the present invention is preferably composed mainly of an aromatic dicarboxylic acid having 8 to 14 carbon atoms and an aliphatic or alicyclic glycol having 2 to 10 carbon atoms. As used herein, the main component refers to 50 mol% or more, preferably 60 mol%, more preferably 65 mol% or more of each component when the total acid component and glycol component are each 100 mol%. When both components are less than 50 mol%, the elongation and mechanical properties of the coating film may be lowered.

  Furthermore, among the polyester resins, the aromatic dicarboxylic acid having 8 to 14 carbon atoms is preferably terephthalic acid and / or isophthalic acid. When these dicarboxylic acids are used, the elongation and mechanical properties of the coating film are further improved. Preferably, the terephthalic acid is contained in an amount of 50 mol% or more, more preferably 60 mol% or more, and one containing both terephthalic acid and isophthalic acid is also preferred.

  The polyester resin (A) may be copolymerized with other polycarboxylic acids other than the above-mentioned terephthalic acid and isophthalic acid. For example, orthophthalic acid, naphthalenedicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, Known materials such as decanoic acid, dimer acid, cyclohexanedicarboxylic acid, trimellitic acid can be used.

  The polyester resin used in the present invention is mainly composed of an aliphatic or alicyclic glycol having 2 to 10 carbon atoms, and further, the aliphatic or alicyclic glycol having 2 to 10 carbon atoms is ethylene glycol or diethylene glycol. , Neopentyl glycol, cyclohexanedimethanol, 1,2-propanediol, 1,3-propanediol, and at least one selected from 2-methyl-1,3-propanediol It is preferable in terms of cost.

  The polyester resin (A) is composed of other than the above-mentioned ethylene glycol, diethylene glycol, neopentyl glycol, cyclohexane dimethanol, 1,2-propanediol, 1,3-propanediol, and 2-methyl-1,3-propanediol. A polyhydric alcohol component may be copolymerized, for example, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5- Pentanediol, hexanediol, nonanediol, dimer diol, ethylene oxide adduct or propylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 2-butyl-2-ethyl-1,3-propanediol The Tricyclodecane, neopentyl hydroxypivalic acid ester, 2,2,4-trimethyl-1,5-pentanediol, trimethylolpropane and the like can be used.

  The polyester resin (A) used in the present invention has a polyfunctional compound having 3 or more carboxyl groups, hydroxyl groups or ester-forming groups thereof in the molecule (for example, trimellitic acid, pyromellitic acid, glycerin, trimethylolpropane). Etc.) is preferably added in an amount of 0.001 to 5 mol% of each of the acid component and glycol component of the polyester in order to improve the blocking resistance.

  The reduced viscosity of the polyester resin used in the present invention is preferably 0.40 to 1.50 dl / g, more preferably 0.50 to 1.20 dl / g, still more preferably 0.60 to 1.00 dl / g. is there. When the number average molecular weight is less than 0.40 dl / g, the coating film is insufficiently stretched due to insufficient resin cohesive strength, and may become brittle and cannot be used. On the other hand, if it exceeds 1.50 dl / g, the melt viscosity is excessively increased, so that the optimum temperature for coating is also increased, and the coating workability may be deteriorated.

The acid value of the polyester resin used in the present invention is preferably 100 equivalents / 10 ⁶ g or less, more preferably 50 equivalents / 10 ⁶ g or less, and still more preferably 40 equivalents / 10 ⁶ g or less. On the other hand, the lower limit is preferably as low as possible, and the lower limit is preferably as close to 0 equivalent / 10 ⁶ g. If the acid value exceeds 100 equivalents / 10 ⁶ g, hydrolysis of the resin may be further accelerated when the resin is heated during kneading with the reactive compound, and the resultant molecular weight may be reduced. Moreover, there is a possibility that varnishing at the time of coating is also deteriorated as the decomposition of the resin proceeds.

  The glass transition temperature of the polyester resin used in the present invention is preferably 40 ° C. or higher and lower than 120 ° C. A preferred lower limit is 50 ° C, more preferably 60 ° C. On the other hand, the upper limit is preferably 110 ° C, more preferably 100 ° C. This is because if the glass transition temperature is less than 40 ° C., the blocking property may decrease, and if it exceeds 120 ° C., the solution viscosity of the coating solution increases, which may adversely affect coating suitability.

  The acrylic resin-based reactive compound (B) used in the present invention introduces a partial cross-link to the entire resin that the hydroxyl group or carboxyl group of the polyester has at least two functional groups per molecule. This is preferable. Due to the effect of the reactive compound, when a reaction product of the hydroxyl group or carboxyl group of the polyester and the reactive compound is produced during melt extrusion, a part of the reaction product becomes a cross-linked product, thereby obtaining an effect of improving the coating film physical properties. It can be done.

  The weight average molecular weight of the reactive compound used in the present invention is 200 in order to satisfy the bending whitening resistance of the coating film depending on the molecular weight increase due to the reaction with the polyester resin and the suppression of bleed out of the unreacted product to the product surface layer. The preferred lower limit is 500 or more, more preferably 700 or more, and most preferably 1000 or more. On the other hand, the preferable upper limit is 300,000 or less, more preferably 100,000 or less, and most preferably 50,000 or less. If the weight average molecular weight of the reactive compound is less than 200, the unreacted reactive compound bleeds out to the surface of the coating film, which can cause a decrease in adhesion to the coating film and plastic substrate, metal, etc., and surface contamination. There is sex. On the other hand, if it exceeds 500,000, voids may occur due to poor compatibility between the reactive compound and the amorphous polyester, and the coating film is likely to be bent and whitened.

  As a specific example of the functional group possessed by the acrylic resin-based reactive compound, a glycidyl group or an isocyanate group is preferable from the speed of reaction.

  Any mode of bonding of the functional groups in the acrylic resin-based reactive compound is possible. For example, those having a functional group in the main chain of the polymer, those existing in the side chain, and those existing in the terminal are all possible.

  In particular, the acrylic resin-based reactive compound includes (X) 20 to 99% by weight of vinyl aromatic monomer, (Y) 1.0 to 80% by weight of hydroxyalkyl (meth) acrylate and / or glycidylalkyl ( A copolymer comprising (meth) acrylate and (Z) 0 to 40% by weight of alkyl (meth) acrylate is preferred. More preferably, the resin comprises (X) of 25 to 90% by weight, (Y) of 10 to 75% by weight, and (Z) of 1.0 to 70% by weight, most preferably (X) of 30 to It is a resin comprising 85% by weight, (Y) 15 to 70% by weight, and (Z) 0 to 30% by weight. Since these compositions affect the functional group concentration contributing to the reaction with the polyester resin system, it is necessary to appropriately control them as described above. When it deviates from the above-mentioned composition, the reactivity with the polyester resin is lowered, and there is a risk of causing varnishing at the time of coating and a decrease in film properties.

  The addition amount of the reactive compound can be individually selected depending on the molecular weight and the number of introduced functional groups, but is preferably 0.1% by weight or more and 20% by weight or less with respect to 100% by weight of the polyester resin, and the lower limit is 0.5% by weight. The upper limit is more preferably 15% by weight or less. If the content is less than 0.1% by weight, the targeted resin sag suppressing effect may not be exhibited, and if it exceeds 20% by weight, the mechanical properties of the product may be affected.

  Regarding the method of adding reactive compounds, a method of press-fitting into a polyester resin at the time of coating, a method of adding and blending the polyester resin pellets before coating, once adding and kneading the polyester resin, dissolving in a solvent and coating A method or the like is conceivable, but any method can be used.

In the polyester resin composition for coating, the blending ratio of the solvent mixed with the solid matter is preferably 5/95 to 50/50 (weight ratio), more preferably 10/90 to 30/70. If the polyester resin composition increases, the solution stability of the coating agent becomes poor. Conversely, if the polyester resin composition decreases, the number of times the coating agent is applied increases, resulting in poor efficiency. In addition, the mixed solvent includes toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, xylene, ethyl acetate, butyl acetate, ethyl cellosolve, methyl cellosolve, butyl cellosolve, ethylene glycol monoacetate, as long as the effects of the present invention are not impaired. A small amount of a polyester resin solvent such as cellosolve acetate may be added.

The melt viscosity of the polyester resin composition of the present invention at 220 ° C. and a shear rate of 100 sec ⁻¹ is preferably 6,000 to 600,000 dPa · sec, more preferably 7,000 to 100,000 dPa · sec, and further preferably 8,000 to 50,000 dPa · sec. is there. If the melt viscosity is less than 6000 dPa · sec, the varnish during processing may be deteriorated. On the other hand, if it exceeds 600,000 dPa · sec, the solution viscosity is too high and the productivity is lowered, which may be impractical.

  A small amount of inorganic components, organic components, other resins, and the like can be added to the polyester resin composition of the present invention. Specific examples thereof include inorganic fine particles such as talc, silica, graphite, carbon powder, pyroferrite, gypsum, and neutral clay, metal oxides such as magnesium oxide, aluminum oxide, and titanium dioxide, sulfates, phosphates, Silicate, oxalate, stearate, benzoate, salicylate, tartrate, sulfonate, montanic acid wax salt, montanic acid wax ester salt, terephthalate, carboxylate, α-olefin and α An ionic copolymer composed of β-unsaturated carboxylic acid.

  The polyester resin composition used in the present invention is used as a composition containing an antioxidant in order to suppress thermal degradation of the polyester resin during processing (to prevent coloring and thermal decomposition of the resin due to thermal degradation). Is desirable. As the antioxidant, for example, a phenol-based antioxidant, an organic phosphite-based compound and the like are suitable.

  Specific examples of the phenolic antioxidant used in the present invention include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, and 2,6-di-tert. -Butyl 4-ethylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,4,6-tri-tert-butylphenol, 2-tert-butyl-4-methoxyphenol, 3-methyl-4-isopropyl Phenol, 2,6-di-tert-butyl-4-hydroxymethylphenol, 2,2-bis (4-hydroxydiphenyl) propane, bis (5-tert-butyl-4-hydroxy-2-methylphenyl) sulfide, 2,5-di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, 1,1- (3-tert-butyl-4-hydroxy-5-methylphenyl) butane, bis (3-tert-butyl-2-hydroxy-5-methylphenyl) methane, 2,6-bis (2-hydroxy-3- tert-butyl-5-methylbenzyl) -4-methylphenol, bis (3-tert-butyl-4-hydroxy-5-methylbenzyl) sulfide, bis (3-tert-butyl-5-ethyl-2-hydroxydiphenyl) Methane, bis (3,5-di-tert-butyl 4-hydroxydiphenyl) methane, bis (3-tert-butyl-2-hydroxy-5-methylphenyl) sulfide, 1,1-bis (4-hydroxyphenyl) Cyclohexane, ethylenebis [3,3-bis (3-tert-butyl-4-hydroxyphenyl) butyrate Bis [2- (2-hydroxy-3-tert-butyl5-methylbenzyl) -4-methyl-6-tert-butylphenyl] terephthalate, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) ) -2-Methylpropane, 4-methoxyphenol, cyclohexylphenol, p-phenylphenol, catechol, hydroquinone, 4-tert-butylpyrocatechol, ethyl gallate, propyl gallate, octyl gallate, lauryl gallate, cetyl gallate, β-naphthol 2,4,5-trihydroxybutyrophenone, tris (3,5-di-tert-butyl-4-hydroxyphenyl) isocyanate, 1,3,5-trimethyl-2,4,6-tris (3,5- Di-tert-butyl-4-hydroxydibenzyl) , 1,6-bis [2- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] hexane, tetrakis [3- (3,5-di-tert-butyl-4-hydroxydiphenyl) ) Propionyloxymethyl] methane, bis (3-cyclohexyl-2-hydroxy-5-methylphenyl) methane, bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] sulfide, n-otatadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, bis [3- (3,5-di-tert-butyl 4-hydroxydiphenyl) propionylamino] hexane, 2, 6-bis (3-tert-butyl-2-hydroxy-5-methylphenyl) -4-methyl Enol, bis [S- (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)] thioterephthalate, tris [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy Ethyl] isocyanurate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,1,3-tris (3-tert-butyl-4-hydroxy-6-methylphenyl) butane, etc. Is mentioned. These compounds may be used alone or in combination of two or more.

  The upper limit of the amount of the phenolic antioxidant is preferably 1.0 part by weight or less, particularly preferably 0.8 part by weight or less, while the preferable lower limit is 0.01 part by weight or more, particularly preferably 0.02 part by weight. That's it. If the blending amount is less than 0.01 parts by weight, it is difficult to obtain the effect of suppressing heat deterioration during processing, and if it exceeds 1.0 part by weight, the effect of suppressing heat deterioration is saturated and not economical.

  Specific examples of the organic phosphite compound used in the present invention include, for example, triphenyl phosphite, tris (methylphenyl) phosphite, triisooctyl phosphite, tridecyl phosphite, tris (2-ethylhexyl). Phosphite, Tris (nonylphenyl) phosphite, Tris (octylphenyl) phosphite, Tris [decylpoly (oxyethylene) phosphite, Tris (cyclohexylphenyl) phosphite, Tricyclohexylphosphite, Tri (decyl) thiophosphite , Triisodecyl thiophosphite, phenyl bis (2-ethylhexyl) phosphite, phenyl diisodecyl phosphite, tetradecyl poly (oxyethylene) bis (ethylphenyl) phosphato, phenyl Dicyclohexyl phosphite, phenyl diisooctyl phosphite, phenyl di (tridecyl) phosphite, diphenyl cyclohexyl phosphite, diphenyl isooctyl phosphite, diphenyl 2-ethylhexyl phosphite, diphenyl isodecyl phosphite, diphenyl・ Cyclohexylphenyl phosphite, diphenyl (tridecyl) thiophosphite, nonylphenyl ditridecyl phosphite, phenyl p-tert-butylphenyl dodecyl phosphite, diisopropyl phosphite, bis [otadecyl poly (oxyethylene)] phosphite , Octyl poly (oxypropylene) tridecyl poly (oxypropylene) phosphite, monoisopropyl phosphite, diisode Ruphosphite, diisooctyl phosphite, monoisooctyl phosphite, didodecyl phosphite, monododecyl phosphite, dicyclohexyl phosphite, monocyclohexyl phosphite, monododecyl poly (oxyethylene) phosphite, bis (cyclohexylphenyl) phosphite Monocyclohexyl phenyl phosphite, bis (p-tert-butylphenyl) phosphite, tetratridecyl 4,4′-isopropylidene diphenyl diphosphite, tetratridecyl 4,4′-butylidene bis (2-tert -Butyl-5-methylphenyl) diphosphite, tetraisooctyl-4,4′-thiobis (2-tert-butyl-5-methylphenyl) diphosphite, tetrakis (nonylphenyl) Poly (propyleneoxy) isopropyl diphosphite, tetratridecyl propyleneoxypropyl diphosphite, tetratridecyl 4,4'-isopropylidene dicyclohexyl diphosphite, pentakis (nonylphenyl) bis [poly (propylene Oxy) isopropyl] triphosphite, heptakis (nonylphenyl) tetrakis [poly (propyleneoxy) isopropyl] pentaphosphite, heptakis (nonylphenyl) tetrakis (4,4′-isopropylidenediphenyl) pentaphosphite, decachys (nonyl) Phenyl) ・ heptakis (propyleneoxyisopropyl) octaphosphite, decaphenyl heptakis (propyleneoxyisopropyl) octaphosphite, bis (butoxycal) Ethyl) · 2,2-dimethylene-trimethylenedithiophosphite, bis (isooctoxycarbomethyl) · 2,2-dimethylenetrimethylenedithiophosphite, tetradodecyl · ethylenedithiophosphite, tetradodecyl · hexamethylenedithio Phosphite, tetradodecyl 2,2'-oxydiethylenedithiophosphite, pentadodecyl di (hexamethylene) trithiophosphite, diphenyl phosphite, 4,4'-isopropylidene-dicyclohexyl phosphite, 4,4'- Isopropylidene diphenyl alkyl (C12-C15) phosphite, 2-tert-butyl-4- [1- (3-tert-butyl-4-hydroxydiphenyl) isopropyl] phenyldi (p-nonylphenyl) phosphite, di Ridecyl 4,4'-butylidenebis (3-methyl-6-tert-butylphenyl) phosphite, dioctadecyl 2,2-dimethylene trimethylene diphosphite, tris (cyclohexylphenyl) phosphite, hexatridecyl 4,4 ′, 4 ″ -1,1,3-butanetriyl-tris (2-tert-butyl-5-methylphenyl) triphosphite, tridodecylthiophosphite, decaphenyl heptakis (propyleneoxyisopropyl) octabosphite Dibutyl pentakis (2,2-dimethylenetrimethylene) diphosphite, dioctylpentakis (2,2-dimethylenetrimethylene) diphosphite, didecyl-2,2-dimethylenetrimethylenediphosphite and their lithium and sodium , Potassium, magnesium, caldium, barium, zinc and aluminum metal salts. These compounds may be used alone or in combination of two or more.

  The compounding amount of the organic phosphite compound is preferably 3.0 parts by weight or less, particularly preferably 2.0 parts by weight or less, and the preferred lower limit is 0.01 parts by weight or more, particularly preferably 0.02. It is more than part by weight. If the blending amount is less than 0.01 parts by weight, it is difficult to obtain the effect of suppressing thermal deterioration during processing, and if it exceeds 3.0 parts by weight, the effect of suppressing thermal deterioration is saturated and not economical.

  Note that it is preferable to use a phenolic antioxidant and an organic phosphite ester compound in combination because the effect of suppressing thermal deterioration is further improved.

  The polyester resin composition of the present invention can further contain a curing agent. As the curing agent, those generally used can be used, and examples thereof include amino resins, isocyanates, epoxy compounds, aziridine compounds, carbodiimide compounds, oxazoline compounds, metal ions, and the like.

  Other components can be appropriately added to the polyester resin composition of the present invention depending on the application. For example, known inorganic pigments such as titanium oxide and silica, surface smoothing agents, antifoaming agents, dispersants, impact resistance improvers, fillers, ultraviolet absorbers, surface treatment agents, lubricants, light stabilizers, pigments, antistatic agents Agents, antibacterial agents, crosslinking agents, sulfur-based antioxidants, flame retardants, plasticizers, processing aids, foaming agents and the like.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. The measurement value described in the synthesis example is measured by the following method.

  Reduced viscosity: 0.1 g of a sample for measurement was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) and measured at 30 ° C. using an Ubbelohde viscosity tube. The unit is indicated by dl / g.

Resin composition: The composition of the amorphous copolyester resin is determined from its integral ratio by performing ¹ H-NMR analysis using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian in a deuterated chloroform solvent. did.

  Glass transition temperature: It was determined by measuring at a temperature elevation rate of 20 ° C./min using a differential scanning calorimeter (DSC) DSC-220 manufactured by Seiko Instruments Inc. It was determined at the temperature of the intersection of the extended line of the base line below the glass transition temperature and the tangent showing the maximum slope at the transition.

  Acid value: Obtained by dissolving 1 g of resin in 30 ml of chloroform and titrating with 0.1N potassium hydroxide ethanol solution. Phenolphthalein was used as the indicator.

<Synthesis example of polyester resin (I)>
187 parts by weight of terephthalic acid, 167 parts by weight of isophthalic acid, 53 parts by weight of sebacic acid, 193 parts by weight of ethylene glycol, 175 parts by weight of neopentyl glycol, zinc acetate in a reaction vessel equipped with a stirrer, a thermometer and a condenser for outflow 0.16 parts by weight of dihydrate, 0.12 parts by weight of antimony trioxide, and 0.12 parts by weight of triethylamine were added, and the esterification reaction was performed at 180 to 220 ° C. under a pressure of 2.0 kgf / cm ² for 2 hours. . After completion of the esterification reaction, the reaction system was heated from 220 ° C. to 240 ° C., while the pressure inside the system was slowly reduced to 500 Pa over 60 minutes. Further, a polycondensation reaction was performed at 130 Pa or lower for 55 minutes to obtain a polyester resin (I).

As a result of NMR analysis of the polyester resin (I), the dicarboxylic acid component is 47 mol% terephthalic acid, isophthalic acid 42 mol%, sebacic acid 11 mol%, the diol component is ethylene glycol 55 mol%, neopentyl glycol 45 mol%. Had. The glass transition temperature was 49 ° C., the reduced viscosity was 0.74 dl / g, and the acid value was 38 equivalents / 10 ⁶ g.

  Polyester resins (II) and (III) were produced in the same manner as polyester resin (I). The composition and measurement results are shown in Table 1. (Figures are mol% in resin)

<Synthesis Example of Reactive Compound (L)>
In a reactor equipped with a stirrer, thermometer, reflux apparatus and quantitative dropping apparatus, 50 parts of methyl ethyl ketone was added and heated to 70 ° C., then 36.4 parts by weight of styrene, 37.3 parts by weight of glycidyl methacrylate, 26. A solution prepared by dissolving 3 parts by weight of the mixture and 2 parts of azobisdimethylvaleronitrile in 50 parts of methyl ethyl ketone was added dropwise to the methyl ethyl ketone in the reactor at 1.2 ml / min, and stirring was further continued for 2 hours. Thereafter, by reducing the pressure, methyl ethyl ketone was removed from the reactor to obtain a reactive compound (L).

  As a result of NMR analysis, this reactive compound (L) had a composition of 40 mol% styrene, 30 mol% glycidyl methacrylate, and 30 mol% methyl methacrylate. The glass transition temperature was 50 ° C. and the weight average molecular weight was 25,000.

<Synthesis Example of Reactive Compound (M)>
Prepared by emulsion polymerization in a 3 liter round bottom flask equipped with stirrer, cooler and heating mantle. The flask was initially charged with a solution consisting of 1800 parts deionized water, 0.4 part acetic acid, 40.01 parts FeSO4, and 0.12 part sodium ethylenediaminetetraacetate dihydrate. The solution was sparged with nitrogen gas and heated to 75 ° C. At 75 ° C, 366.1 parts of styrene, 14.4 parts of hydroxyethyl methacrylate, and 95.5 parts of butyl methacrylate monomer emulsified with 5.4 parts of sodium dodecylbenzenesulfonate in 150 parts of water are added to the flask. Then, 0.45 parts of sodium persulfate was added as an initiator. The reaction was then allowed to proceed for about 2 hours or until more than 99.9% of the monomer was replaced by investigation of solids content. After completion of the reaction, the emulsion was cooled to room temperature and then spray dried to obtain a white powder.

  As a result of NMR analysis, this reactive compound (M) had a composition of monomer components of 77 mol% styrene, 3 mol% hydroxyethyl methacrylate, and 20 mol% butyl methacrylate. The glass transition temperature was 50 ° C., and the weight average molecular weight was 200,000.

<Synthesis Example of Reactive Compound (N)>
The monomer component was synthesized by the same method as the reactive compound (L), and as a result of NMR analysis, the monomer component had a composition of styrene 75 mol%, glycidyl methacrylate 4 mol%, and butyl methacrylate 21 mol%. The weight average molecular weight was 300,000.

<Example 1>
100 parts by weight of polyester (I), 2 parts by weight of reactive compound (L), bis [S- (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)] thioterephthalate 0.2 as a stabilizer The parts by weight were mixed, and the mixture was kneaded with an extruder (L / D = 30, screw diameter = 20 mm, full flight, compression ratio 2.0) set at a rotation speed of 30 rpm and a total barrel temperature of 180 ° C. The reduced viscosity of this resin composition was 0.82 dl / g. Further, 100 parts by weight of the resin composition was dissolved in a resin varnish dissolved in 120 parts by weight of cyclohexanone and 120 parts by weight of Solvesso-150 to obtain a coating composition.

Adhesion After coating the coating composition on the substrate (PET) surface and drying at 120 ° C. for 30 minutes to form a coating film (10 μm), the coating film was applied at room temperature according to the cross-cut test of JISK5400 The cellophane tape was applied to the 100 cell / cm ² and the cellophane tape was applied and rolled down sufficiently, and then the cellophane tape was peeled off at once and the adhesion was examined by the number of cells remaining on the substrate. The evaluation criteria are as follows.
○: More than 80 per 100 squares remained.
X: Less than 80 squares remained.

Heat resistance (blocking resistance)
Put the coated PET substrate in the dryer at 40 ° C in the same way as the above adhesion evaluation, take it out to room temperature after 4 hours, and immediately paste the PET film (100μ) that had been cured at room temperature on the coated surface. (0.1 kg / cm ² × 10 sec) The blocking property was examined.
The evaluation criteria are as follows.
○: PET film does not adhere.
X: PET film adheres.

Bending workability After coating the coating composition on the surface of the base material (chin-free steel) and drying at 120 ° C. for 30 minutes to form a coating film (10 μm), the test piece has the same thickness as chin-free After sandwiching two steel substrates and bending them in the direction of 180 degrees, the bent processed parts were observed with a magnifying glass to determine the presence or absence of cracks in the film.
○: Good ×: Cracked

<Examples 2 and 3 and Comparative Examples 1 to 4>
Using the raw materials described in Tables 2 and 3, molding was performed in the same manner as in Example 1 under the conditions described in the respective tables.

  In Tables 2 and 3, the amount of polyester is 100 parts by weight, and the other reactive compound amounts, stabilizer amounts and additive amounts are parts by weight with respect to 100 parts by weight of polyester.

As can be seen from Tables 2 and 3, Examples 1 to 3 improve the adhesion of the polyester resin composition for coating to the PET substrate, the blocking resistance, the adhesion to metal and the bending workability of the test piece. Is able to.
On the other hand, Comparative Example 1 contains two or more glycidyl groups and / or isocyanate groups per molecule and does not contain an acrylic resin-based reactive compound having a weight average molecular weight of 200 to 500,000. Outside. Since Comparative Example 2 is not an acrylic resin-based reaction compound, it is outside the scope of the present invention, and the bending workability is inferior. In Comparative Example 3, the molecular weight of the acrylic resin-based reactive compound exceeds 500,000, which is outside the scope of the present invention. Further, the reaction with the polyester resin proceeded excessively, a large amount of gel was generated, the smoothness of the coating film was lowered, and the bending workability was deteriorated.

  The coating composition comprising the polyester resin of the present invention as a main component is excellent in adhesiveness to plastic film substrates such as polyethylene terephthalate (PET) and metals, and has good heat resistance and workability. It is useful as a coating agent for paints, anchor coating materials and various binders.

Claims (8)

A polyester resin (A) having an acid value of 100 equivalents / 10 ⁶ g or less;
It contains two or more glycidyl groups per molecule, has a weight average molecular weight of 200 to 500,000, (X) 20 to 98% by weight of vinyl aromatic monomer and (Y) 1.0 to 79% by weight of glycidyl alkyl. An acrylic resin-based reactive compound (B) comprising (meth) acrylate and (Z) 1.0 to 70% by weight of alkyl (meth) acrylate;
A solvent,
The acrylic resin-based reactive compound (B) is contained in an amount of 0.1% by weight to 20% by weight with respect to 100% by weight of the polyester resin (A), and the blending ratio of the solid matter and the solvent to be mixed is 5/95. A polyester resin composition for coating, which is -50/50 (weight ratio , solid content / solvent ).   The polyester resin composition for coating according to claim 1, wherein the polyester resin (A) is amorphous.   The polyester resin (A) contains 0.001 to 5 mol% of a polyfunctional compound unit having three or more carboxyl groups, hydroxyl groups or ester-forming groups thereof in the molecule of the acid component and / or glycol component of the polyester. The polyester resin composition for coating according to any one of claims 1 and 2.   The polyester resin (A) contains an aromatic dicarboxylic acid having 8 to 14 carbon atoms and an aliphatic or alicyclic glycol having 2 to 10 carbon atoms in an amount of 50 mol% or more of each of the acid component and the glycol component. Item 4. The polyester resin composition for coating according to any one of Items 1 to 3.   The polyester resin composition for coating according to claim 4, wherein the aromatic dicarboxylic acid having 8 to 14 carbon atoms is terephthalic acid and / or isophthalic acid.   Aliphatic or alicyclic glycols having 2 to 10 carbon atoms are ethylene glycol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, 1,2-propanediol, 1,3-propanediol and 2-methyl-1,3-propane. The polyester-based resin composition for coating according to claim 4 or 5, wherein the composition is at least one selected from the group consisting of diols.   The polyester resin composition for coating according to any one of claims 1 to 6, wherein the glass transition temperature of the polyester resin (A) is 40 ° C or higher and lower than 120 ° C.   0.1 g of the polyester resin (A) was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4), and the reduced viscosity measured at 30 ° C. using an Ubbelohde viscosity tube was 0.4 dl / g or more. The polyester resin composition for coating according to any one of claims 1 to 7.