JP2013181080A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which can be easily made into a coating because a polyester copolymer contained has excellent solubility and which provides excellent heat resistance and flexibility when made into the coating even when the molecular weight of the polyester copolymer is low.SOLUTION: A resin composition includes a polyester copolymer and a curing agent, wherein the polyester copolymer has a polyester polymer including a polycarboxylic acid component and a glycol component as the main chain, one carboxyl group and one acid anhydride group are introduced into the terminal of the polyester polymer by blocking the terminal with a tetracarboxylic dianhydride having a specific structure, and a number average molecular weight is 1,000-50,000.

Description

  The present invention relates to a resin composition containing a polyester copolymer whose end is sealed with a tetracarboxylic dianhydride having a specific structure and a curing agent.

  Polyester resins such as polyethylene terephthalate and polybutylene terephthalate are excellent in mechanical strength, thermal stability, hydrophobicity, chemical resistance, etc., and are therefore widely used in various fields as molding materials such as fibers, films, and sheets. ing.

  In the polyester resin, various structures and characteristics can be obtained by appropriately selecting the combination of the types of polyvalent carboxylic acid and glycol as constituent components. And polyester resin is excellent in adhesiveness with this base material when various base materials are coated. Furthermore, the coating film obtained by coating the base material with a polyester resin is excellent in adhesiveness to other base materials. Taking advantage of such excellent adhesion and adhesiveness, polyester resins are widely used in applications such as adhesives, coating agents, ink binders and paints.

  The polyester resin can be improved in rigidity and heat resistance by introducing a rigid skeleton such as an aromatic ring structure or an alicyclic structure. For example, Patent Document 1 describes a polyester resin containing a diol unit having a cyclic acetal skeleton. Patent Document 2 describes using a compound having a tricyclodecane skeleton.

  Although the heat resistance of the polyester resins described in Patent Document 1 and Patent Document 2 is improved to some extent, a general-purpose organic solvent such as toluene is derived from the fact that the constituent component includes a compound having a rigid skeleton. The solubility in water will be extremely low. Usually, when a resin is formed into a coating film, it is described in Patent Document 1 and Patent Document 2 because the substrate is coated with a solution obtained by dissolving the resin in an organic solvent and then dried. There has been a problem that it is impossible to form a polyester resin having low solubility as described above.

  Furthermore, in order to improve the heat resistance of the coating film obtained from the polyester resin, it has been studied to improve the glass transition temperature while maintaining the solubility of the polyester resin in an organic solvent. For example, Patent Document 3 and Patent Document 4 describe that the copolymer polyester resin obtained has a specific composition, thereby improving the glass transition temperature and thus improving the heat resistance. . However, the thermal properties of the copolyester resins described in Patent Documents 3 and 4 are not yet sufficient, and in addition, there is a problem in that the flexibility when used as a coating film is inferior.

  Patent Document 5 describes that a polyester resin with improved heat resistance is obtained by reducing the molecular weight of the polyester resin and increasing the number of terminal groups. However, in the case of Patent Document 5, due to the low molecular weight, the crosslink density of the resulting polyester resin becomes too high, so there is a problem that the flexibility when it is made a coating film is not sufficient. .

  Further, the present inventors have studied to make a polyester copolymer into which an acid anhydride group having one carboxyl group is introduced with respect to the terminal of the polyester resin (unpublished in application). However, when such a polyester copolymer is formed into a coating film, there is a problem that flexibility is still insufficient when the molecular weight is low. Moreover, when the molecular weight of the obtained polyester copolymer is high, although heat resistance and flexibility are improved to some extent, there is a problem that it is difficult to form a coating film because of poor solubility in an organic solvent.

  The problems in the prior art are summarized below. That is, in the method of improving the heat resistance by improving the glass transition temperature by introducing a compound having a rigid skeleton into the composition, the solubility of the resulting polyester copolymer in an organic solvent is reduced. As a result, it is difficult to form a coating film on the polyester copolymer. Further, in the method for improving the heat resistance of the polyester copolymer by increasing the number of terminal groups to increase the crosslinking density, there is a problem that flexibility is sacrificed. Moreover, in the method of increasing the molecular weight of the polyester copolymer to improve the heat resistance, there is a problem that the solubility in an organic solvent is not sufficient and it is difficult to form a coating film. Furthermore, in any of the above methods, the heat resistance of the resulting polyester copolymer is not sufficient. In other words, in the prior art, it is difficult to obtain a polyester copolymer that is excellent in solubility and can be easily formed into a film, and that is remarkably excellent in both heat resistance and flexibility when formed into a coating film. It is.

JP 2003-292593 A JP 2003-119259 A JP 2011-190348 A JP 2011-190349 A JP 2006-182983 A

  The present invention is intended to solve the above-mentioned problems, and since the polyester copolymer contained is excellent in solubility, it is easy to form a coating film, and the polyester copolymer has a low molecular weight. However, it is a technical problem to obtain a resin composition having excellent heat resistance and flexibility in the case of a coating film.

なお、上記式（Ｉ）において、Ｘは、直接結合であるか、あるいはカルボニル基、オキソ基、スルホニル基、および−Ｃ（ＣＦ_３）_２−で表される基から選ばれた１種以上の基を示す。

（２）ポリエステル共重合体のガラス転移点が−２０〜７５℃であることを特徴とする（１）の樹脂組成物。
（３）ポリエステル共重合体が、該ポリエステル共重合体に含まれる多価カルボン酸成分の全量に対し１〜１８ｍｏｌ％であるテトラカルボン酸二無水物を用いて封止されたものであることを特徴とする（１）または（２）の樹脂組成物。
（４）硬化剤が、４，４’−ジフェニルメタンジイソシアネートであることを特徴とする（１）〜（３）のいずれかの樹脂組成物。
（５）（１）〜（４）のいずれかの樹脂組成物を製造する方法であって、下記（ｉ）および（ｉｉ）の工程をこの順に有することを特徴とする樹脂組成物の製造方法。
（ｉ）多価カルボン酸およびグリコールを重合して主鎖となるポリエステル樹脂を得た後、該ポリエステル樹脂の末端水酸基量を基準として、上記式（Ｉ）、式（ＩＩ）および式（ＩＩＩ）のいずれかで表されるテトラカルボン酸二無水物を１．０〜３．０当量の割合で添加し、末端に１個のカルボキシル基と１個の酸無水物基とが導入されたポリエステル共重合体を得る工程。
（ｉｉ）（ｉ）で得られたポリエステル共重合体を溶剤に溶解した後、次いで硬化剤を添加し、樹脂組成物を得る工程。
（６）（１）〜（４）のいずれかの樹脂組成物から形成された塗膜。 As a result of intensive studies to solve the above problems, the present inventors have found that a polyester copolymer and a curing agent in which a terminal of a polyester polymer as a main chain is sealed with a tetracarboxylic dianhydride having a specific structure As a result, the present inventors have found that the above-mentioned problems can be solved.
That is, the gist of the present invention is as follows.
(1) A resin composition comprising a polyester copolymer and a curing agent, wherein the polyester copolymer has a polyester polymer containing a polyvalent carboxylic acid component and a glycol component as a main chain, and the terminal of the polyester polymer. Is sealed with a tetracarboxylic dianhydride represented by any one of the following formulas (I), (II) and (III), whereby one carboxyl group and one acid are present at the terminal. A resin composition having an anhydride group introduced therein and a number average molecular weight of 1,000 to 50,000.

In the above formula (I), X is a direct bond, or one or more selected from a group represented by a carbonyl group, an oxo group, a sulfonyl group, and —C (CF ₃ ) ₂ —. Indicates a group.

(2) The resin composition according to (1), wherein the glass transition point of the polyester copolymer is -20 to 75 ° C.
(3) The polyester copolymer is sealed with a tetracarboxylic dianhydride that is 1 to 18 mol% with respect to the total amount of the polyvalent carboxylic acid component contained in the polyester copolymer. (1) or (2) resin composition characterized by the above-mentioned.
(4) The resin composition according to any one of (1) to (3), wherein the curing agent is 4,4′-diphenylmethane diisocyanate.
(5) A method for producing a resin composition according to any one of (1) to (4), comprising the following steps (i) and (ii) in this order: .
(I) After obtaining a polyester resin as a main chain by polymerizing polyvalent carboxylic acid and glycol, the above formula (I), formula (II) and formula (III) based on the amount of terminal hydroxyl groups of the polyester resin A tetracarboxylic dianhydride represented by any of the above is added at a ratio of 1.0 to 3.0 equivalents, and a polyester copolymer in which one carboxyl group and one acid anhydride group are introduced at the terminal is provided. A step of obtaining a polymer.
(Ii) A step of dissolving the polyester copolymer obtained in (i) in a solvent and then adding a curing agent to obtain a resin composition.
(6) The coating film formed from the resin composition in any one of (1)-(4).

  In the resin composition of the present invention, the polyester copolymer contained is sealed with a tetracarboxylic dianhydride having a specific structure at the end of the polyester polymer as the main chain. Even when the molecular weight of the copolymer is not increased, the effect of excellent heat resistance and flexibility in the case of a coating film can be obtained. Moreover, since the molecular weight of the polyester copolymer contained can be lowered, the copolymer is excellent in solubility in a general-purpose organic solvent. As a result, a resin composition that can be easily formed into a coating film is obtained. Can be obtained. Furthermore, since the resin composition of the present invention is excellent in rigidity, it is suitably used in applications where it is used as a coating film.

Hereinafter, the present invention will be described in detail.
The resin composition of this invention contains the polyester copolymer by which the terminal of the polyester polymer which is a principal chain was sealed with the tetracarboxylic dianhydride which has a specific structure, and a hardening | curing agent.

First, the polyester copolymer will be described.
The polyester copolymer contained in the resin composition of the present invention is a tetracarboxylic dianhydride having a polyester polymer containing a polyvalent carboxylic acid component and a glycol component as a main chain, and the terminal of the polyester polymer having a specific structure. (Hereinafter sometimes referred to simply as “tetracarboxylic dianhydride”), one carboxyl group and one acid anhydride group are introduced at the terminal. is there.

  The polyvalent carboxylic acid component contained in the polyester polymer that is the main chain is not particularly limited. Sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosanedioic acid, docosanedioic acid, phthalic acid, Naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, 5-sodium sulfoisophthalic acid, 5-hydroxy-isophthalic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,3,4-benzenetricarboxylic acid Acid, 1,2,4,5-benzenetetracarboxylic acid, Mellitic acid, trimellitic acid, oxalic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid, dimer acid, hydrogenated dimer acid, etc. Or an anhydride thereof. Among these, terephthalic acid and isophthalic acid are preferably included from the viewpoint of durability and the like.

  The glycol component contained in the polyester polymer is not particularly limited. For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, 1, Examples include 3-cyclohexanedimethanol, tricyclodecane dimethanol, spiroglycol, dimer diol, neopentyl glycol, 2,2-butylethylpropanediol, 1,2-propanediol, and the like. Of these, ethylene glycol, neopentyl glycol, and 1,2-propanediol are preferable from the viewpoint of solubility.

  The polyester polymer as the main chain may contain a monomer component (other monomer component) other than the polyvalent carboxylic acid component and the glycol component, if necessary, as long as the effects of the present invention are not impaired. In addition, it is preferable that the copolymerization ratio of the other monomer component in the polyester polymer which is a main chain is less than 50 mol% with respect to all the monomer components contained in the polyester polymer.

  Examples of other monomer components include tetrahydrophthalic acid, lactic acid, oxirane, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, Hydroxycarboxylic such as 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid Acid; aliphatic lactones such as β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

  Moreover, monocarboxylic acid, monoalcohol, etc. may be used as another monomer component. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. It is done. Examples of monoalcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, 2-phenoxyethanol and the like.

  A tetracarboxylic dianhydride for sealing a polyester polymer is a compound having two acid anhydride groups. In the present invention, the tetracarboxylic dianhydride needs to be represented by any of the following formulas (I), (II) and (III), that is, the aromatic ring It is necessary to have.

なお、上記式（Ｉ）において、Ｘは、直接結合であるか、あるいはカルボニル基（−ＣＯ−）、オキソ基（−Ｏ−）、スルホニル基（−ＳＯ_２−）、および−Ｃ（ＣＦ_３）_２−で表される基から選ばれた１種以上の基を示す。

In the above formula (I), X is a direct bond, or a carbonyl group (—CO—), an oxo group (—O—), a sulfonyl group (—SO ₂ —), and —C (CF ₃ 1) One or more groups selected from the group represented by _2- .

  The following effects are produced by using the tetracarboxylic dianhydride as described above. That is, even when tetracarboxylic dianhydride having a rigid skeleton is used to seal the end of the main chain, flexibility and heat resistance are improved when a coating film is formed without increasing the molecular weight. A resin composition containing an excellent polyester copolymer can be obtained. And since such a polyester copolymer can be adjusted to a low molecular weight, it is excellent in solubility in an organic solvent. That is, a resin composition containing such a polyester copolymer is There is an advantage that coating is easy.

  In addition, the tetracarboxylic dianhydride represented by the said formula (I) is specifically represented by following formula (IV)-(VIII).

上記式（ＩＶ）においては、上記式（Ｉ）中のＸがカルボニル基を示すものであり、このテトラカルボン酸二無水物は、３，３’，４，４’−ベンゾフェノンテトラカルボン酸二無水物である。

In the formula (IV), X in the formula (I) represents a carbonyl group, and this tetracarboxylic dianhydride is 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride. It is a thing.

上記式（Ｖ）においては、上記式（Ｉ）中のＸが直接結合を示すものであり、このテトラカルボン酸二無水物は、４，４’−ビフタル酸無水物である。

In the above formula (V), X in the above formula (I) represents a direct bond, and this tetracarboxylic dianhydride is 4,4′-biphthalic anhydride.

上記式（ＶＩ）においては、上記式（Ｉ）中のＸがスルホニル基を示すものであり、このテトラカルボン酸二無水物は、３，３’，４，４’−ジフェニルスルホンテトラカルボン酸二無水物である。

In the above formula (VI), X in the above formula (I) represents a sulfonyl group, and this tetracarboxylic dianhydride is a 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid dicarboxylic acid. Anhydrous.

上記式（ＶＩＩ）においては、上記式（Ｉ）中のＸが、−Ｃ（ＣＦ_３）_２−で表される基を示すものであり、このテトラカルボン酸二無水物は、４，４’−（ヘキサフルオロイソプロピリデン）ジフタル酸無水物である。

In the above formula (VII), X in the above formula (I) represents a group represented by —C (CF ₃ ) ₂ —, and this tetracarboxylic dianhydride is 4,4 ′. -(Hexafluoroisopropylidene) diphthalic anhydride.

上記式（ＶＩＩＩ）においては、上記式（Ｉ）中のＸが、オキソ基を示すものであり、このテトラカルボン酸二無水物は、４，４’−オキシジフタル酸無水物である。

In the above formula (VIII), X in the above formula (I) represents an oxo group, and this tetracarboxylic dianhydride is 4,4′-oxydiphthalic anhydride.

  The compound represented by the above formula (II) is 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride. The compound represented by the above formula (III) is 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride.

  Among these, 4,4'-biphthalic anhydride represented by the formula (V) having a high melting point is preferable from the viewpoint of improving the heat resistance when a coating film is formed because the melting point is high.

  In addition, when the terminal is blocked using a compound having two acid anhydride groups other than those represented by the above formulas (I) to (III), while maintaining the molecular weight in a low range, A polyester copolymer having excellent flexibility and heat resistance when formed into a coating film cannot be obtained. In addition, in a polyester copolymer using a compound having two acid anhydride groups other than those represented by the above formulas (I) to (III), if the molecular weight is increased in order to improve heat resistance, It becomes inferior in solubility in a solvent, and cannot be a resin composition that can be easily formed into a coating film. That is, in the present invention, by sealing the end with a tetracarboxylic dianhydride having the specific structure as described above, even when the molecular weight is low, the flexibility of the coating film and It has been found for the first time that a resin composition containing a polyester copolymer having excellent heat resistance is obtained.

  Commercially available products can be suitably used for the tetracarboxylic dianhydrides represented by the above formulas (II) to (VIII). For example, these are available from Tokyo Chemical Industry.

  In the polyester copolymer, in order to introduce one carboxyl group and one acid anhydride group at the terminal of the polyester polymer as the main chain, the above formula ( It is preferable to add tetracarboxylic dianhydrides represented by I) to (III). By doing in this way, it can be set as the polyester copolymer by which this terminal was sealed with specific tetracarboxylic dianhydride. More specifically, the -O- moiety of the acid anhydride group in the tetracarboxylic dianhydride is ring-opened by causing an addition reaction by attacking the OH group that is the terminal group of the polyester resin. As a result, a polyester copolymer in which an acid anhydride group having one carboxyl group is introduced at the terminal of the polyester polymer can be obtained.

  More specifically, the -O- moiety of the tetracarboxylic dianhydride represented by the above formulas (I) to (III) is opened, and the following formulas (i) to (iii) The group represented. This group seals the terminal of the polyester resin, whereby the polyester copolymer of the present invention in which one carboxyl group and one acid anhydride group are introduced into the terminal of the polyester polymer is obtained.

  Specifically, the molecular weight of the polyester copolymer contained in the resin composition of the present invention is indicated by a number average molecular weight. The number average molecular weight of the polyester copolymer needs to be 1000 to 50000, preferably 5000 to 40000, more preferably 7500 to 35000, and still more preferably 10,000 to 30000. . If the number average molecular weight is less than 1000, the cross-linking density of the polyester copolymer contained is increased, so that there is a problem that only a resin composition having poor flexibility can be obtained.

  On the other hand, when the number average molecular weight of the polyester copolymer exceeds 50,000, the density of the tetracarboxylic dianhydride having a specific structure is lowered, the heat resistance is inferior, and the gelation occurs. It becomes inferior. Furthermore, when the resin composition containing the polyester copolymer is used as a coating film, the surface smoothness of the coating film is inferior. In addition, since the solubility of the polyester copolymer in an organic solvent is inferior, it may be difficult to form a resin composition containing the polyester copolymer. In the present invention, as described above, by using a tetracarboxylic dianhydride having a specific structure, even if the polyester copolymer contained therein has a low number average molecular weight, When it is made, it can be set as the resin composition which is excellent in flexibility and heat resistance.

  In the polyester copolymer contained in the resin composition of the present invention, the sealing amount of tetracarboxylic dianhydride is 1 to 18 mol% with respect to the total amount of polyvalent carboxylic acid components contained in the polyester copolymer. It is preferable that it is 1-15 mol%, it is more preferable that it is 1-12 mol%, and it is most preferable that it is 1-9 mol%.

  If it is less than 1 mol%, gelation may proceed when a compound having one carboxyl group and one acid anhydride group is added to the polyester polymer, which is not preferable. On the other hand, when the sealing amount exceeds 18 mol%, when the film is obtained from the resin composition of the present invention containing such a polyester copolymer, the acid anhydride group becomes excessive, and the excess acid anhydride The polyester copolymer itself is plasticized. As a result, such a coating film is not preferred because durability may be inferior.

  The glass transition point of the polyester copolymer contained in the resin composition of the present invention is preferably -20 to 75 ° C, more preferably -10 to 70 ° C, and 0 to 65 ° C. Is more preferable. If the glass transition temperature is less than −20 ° C., a polyester copolymer having inferior heat resistance is obtained even when cured, and as a result, only a resin composition having inferior heat resistance may be obtained. On the other hand, if the glass transition temperature exceeds 75 ° C., the melt viscosity of the polyester copolymer becomes too high, so the polymerization temperature needs to be high. As a result, since the polyester copolymer is thermally decomposed and deteriorated, a polyester copolymer having a required number average molecular weight may not be obtained or the resulting resin composition may be inferior in adhesiveness. This is not preferable.

  Moreover, the polyester copolymer of the present invention may be crystalline or amorphous.

  The resin composition of the present invention contains the above polyester copolymer and a curing agent. In the present invention, by using a polyester copolymer having a specific configuration and a curing agent in combination, for the first time, not only the solubility, heat resistance, and flexibility are excellent, but also rigidity is not impaired. A resin composition with improved properties could be obtained.

  Examples of the curing agent contained in the resin composition include the functional group of the polyester copolymer as described above, or a functional group formed by the reaction of the polyester copolymer (for example, a carboxyl group, an anhydride thereof, a hydroxyl group). , Epoxy group, isocyanate group, and the like) as long as the compound has reactivity.

  Specific examples of curing agents include phenolic resins, urea, melamine, benzoguanamine, acetoguanamine and other formaldehyde adducts; urea, acrylamide and other glyoxal adducts; alkyl compounds of these adducts with alcohols having 1 to 6 carbon atoms An amino resin; an epoxy resin; an isocyanate compound and various blocked isocyanate compounds thereof; an aziridine compound; a carbodiimide group-containing compound; an oxazoline group-containing compound.

  Among these, an isocyanate compound and its various blocked isocyanate compounds, an epoxy resin, and an oxazoline group compound are preferable in terms of excellent curing reactivity. From the viewpoint of excellent curing reactivity at a relatively low temperature of 150 ° C. or lower, an isocyanate compound and various blocked isocyanate compounds thereof are preferable.

Isocyanate compounds include aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), aliphatic diisocyanate monomers such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and the like. Is a trimer. Of these, aromatic diisocyanates are particularly preferable because of their high curing reaction rate. On the other hand, an amino resin can also be preferably used as a curing agent because a coating film having excellent solvent resistance and processability can be formed.

  The resin composition of the present invention may contain a curing catalyst, if necessary, as long as the effects of the present invention are not impaired. The curing catalyst is not particularly limited, and examples thereof include metal salts such as octyl tin, amine-based curing catalysts, and the like.

  The content ratio of the polyester copolymer and the curing agent in the resin composition of the present invention differs depending on whether an isocyanate monomer is used as the curing agent or an isocyanate trimer. In the case of using an isocyanate monomer, it is usually preferable that the isocyanate group of the curing agent is 0.5 to 35 times the mole of the terminal carboxyl group of the polyester copolymer, and 0.8 to 10 times. More preferably, it is 0.9-7 times mole, and most preferably 1.0-5 times mole. When the amount is less than 0.5 times mol, curing of the polyester copolymer may be insufficient. On the other hand, when the amount exceeds 35 times mol, the curing agent may be excessive and cause gelation.

  When an isocyanate trimer is used as the curing agent, it is usually preferable that the isocyanate group of the curing agent is 0.9 to 45 times the mole of the terminal carboxyl group of the polyester copolymer, and 1.2 to It is more preferably 15 times the mole, more preferably 1.4 to 9 times the mole, and most preferably 1.6 to 6 times the mole. If it is less than 0.9-fold mol, the polyester copolymer may be insufficiently cured. On the other hand, when it exceeds 45 times mole, it may no longer be excessive and may cause gelation.

Next, the manufacturing method of the resin composition of this invention is demonstrated.
The method for producing a resin composition of the present invention is characterized by having the following steps (i) and (ii) in this order.
(I) After obtaining a polyester resin as a main chain by polymerizing polyvalent carboxylic acid and glycol, the above formula (I), formula (II) and formula (III) based on the amount of terminal hydroxyl groups of the polyester resin A tetracarboxylic dianhydride represented by any of the above is added at a ratio of 1.0 to 3.0 equivalents, and a polyester copolymer in which one carboxyl group and one acid anhydride group are introduced at the terminal is provided. A step of obtaining a polymer.
(Ii) A step of dissolving the polyester copolymer obtained in (i) in a solvent and then adding a curing agent to obtain a resin composition.

Step (i) will be described below.
First, a polyester resin to be a main chain polyester polymer is produced, for example, by the following method. That is, an esterification reaction is carried out after introducing raw material monomers such as polycarboxylic acid and glycol into the reaction vessel. Next, a polyester resin can be produced by polycondensation until a desired molecular weight is reached by a known method. The esterification reaction is performed, for example, at a temperature of 180 ° C. or higher for 4 hours or longer.

The polycondensation reaction is generally performed using a polymerization catalyst under a reduced pressure of 130 Pa or less and a temperature of 220 to 280 ° C. Examples of the polymerization catalyst include titanium compounds such as tetrabutyl titanate, metal acetates such as zinc acetate, magnesium acetate, and zinc acetate, and organic tin compounds such as antimony trioxide, hydroxybutyltin oxide, and tin octylate. It is done. If the amount of the polymerization catalyst used is too small, the polymerization reaction may be slow. On the other hand, if the amount is too large, the color tone of the resulting polyester copolymer may be lowered. 0.1 to 20 × 10 ⁻⁴ mol is preferable.

  The polyester resin thus obtained is represented by any one of the above formulas (I), (II) and (III) in an amount of 1.0 to 3.0 equivalents based on the amount of terminal hydroxyl groups. A polyester copolymer in which one carboxyl group and one acid anhydride group are introduced at the terminal can be produced by addition reaction of tetracarboxylic dianhydride. In addition, what is necessary is just to make both contact, for example, by adding tetracarboxylic dianhydride to a polyester resin in order to carry out addition reaction.

  Tetracarboxylic dianhydride is preferably used in an amount of 1.0 to 3.0 equivalents, more preferably 1.0 to 2.0 equivalents, based on the amount of terminal hydroxyl groups of the polyester resin. More preferably, it is used at 1.5 equivalents. By adding tetracarboxylic dianhydride in excess of the amount of terminal hydroxyl groups, the addition reaction of acid anhydride groups to the polyester resin proceeds sufficiently without excess and deficiency so that no hydroxyl groups remain in the polyester polymer. be able to. Therefore, it is possible to obtain a rigid polyester copolymer in which the ends of the polyester polymer are sealed while suppressing the occurrence of a gelation reaction that causes an additional reaction one after another.

  On the other hand, when the amount of tetracarboxylic dianhydride used exceeds 3.0 equivalents, excessive acid anhydride groups (that is, unreacted acid anhydride groups) that are not used in the addition reaction to the polyester resin are excessive. Remains. For this reason, in the resin composition containing the polyester copolymer of the present invention and a curing agent, the reaction between the unreacted acid anhydride group and the curing agent causes less curing agent to act on the polyester copolymer. In other words, the polyester copolymer is not sufficiently cured, and the effect of improving the rigidity exhibited when used in combination with the curing agent described below may not be sufficiently exhibited. The unreacted tetracarboxylic dianhydride may be removed by washing using an appropriate solvent or the like.

Next, step (ii) will be described.
In order to obtain the resin composition of the present invention, the following method can be employed. That is, the polyester copolymer of the present invention obtained as described above is dissolved in a general-purpose organic solvent to obtain a solution. And what is necessary is just to mix | blend a hardening | curing agent and a hardening catalyst as needed with this solution.

  In the resin composition of the present invention, the blending ratio of the polyester copolymer and the curing agent is usually such that the isocyanate groups of the curing agent are approximately equal to the terminal carboxyl group amount of the polyester copolymer. It is preferably carried out, more preferably 0.7 to 2.0 times mol, further preferably 0.8 to 1.5 times mol, and 0.9 to 1.3 times mol. Particularly preferred. If the amount is less than 0.7 times mole, it may be difficult to perform sufficient curing, and if it exceeds 2.0 times mole, the curing agent may be excessively excessive and cause gelation.

  In addition, although it does not specifically limit as a general purpose organic solvent, Toluene, methyl ethyl ketone, alcohol, or these aqueous solution etc. are mentioned.

  The coating composition of the present invention can be obtained by coating (applying) the resin composition of the present invention on various substrates and then drying to remove the organic solvent.

  Here, although a coating film is formed by a curing reaction between the polyester copolymer and the curing agent, the curing reaction can be promoted by further aging after the application of the resin composition. The aging conditions vary depending on the type of polyester copolymer and curing agent used, their composition, and the like, but can be adjusted as appropriate. For example, the aging temperature is preferably 40 to 60 ° C., and the aging time is preferably 72 to 120 hours. The aging time can be shortened by setting the aging temperature higher.

  The substrate on which the resin composition of the present invention is coated is not particularly limited, but is a film or sheet made of a resin such as a polyester resin, a polycarbonate resin or a polyvinyl chloride resin, or a metal foil such as aluminum or copper. Etc. Moreover, it does not specifically limit about the method and conditions which perform coating and drying, It can carry out by a well-known method.

  The coating film containing the resin composition of the present invention is not only excellent in flexibility, heat resistance and rigidity, but also excellent in adhesion to a substrate and adhesion to other substrates. Therefore, it is particularly suitably used in applications such as adhesives and coating agents.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to these examples.

Evaluation methods and measurement methods are as follows.
(1) Acid value of polyester copolymer The acid value of the polyester copolymer in a state where the acid anhydride group at the terminal is ring-opened was measured.
The obtained polyester copolymer was washed with a solvent (dimethyl sulfoxide) and weighed 0.5 g precisely. Subsequently, it melt | dissolved for 40 minutes at 150 degreeC with respect to 50 ml dioxane aqueous solution [(dioxane) / (water) = 9/1, volume ratio]. At this time, it is presumed that the terminal acid anhydride group of the polyester copolymer is ring-opened. Then, after cooling to room temperature, titration was performed with 0.1 mol / L potassium hydroxide methanol solution using cresol red as an indicator, and the number of mg of KOH consumed for neutralization was divided by the number of grams of polyester resin. The value was determined as the acid value.

(2) Number average molecular weight of polyester copolymer Using a liquid feeding unit (manufactured by Shimadzu Corporation, “LC-10ADvp type”) and an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, “SPD-6AV type”) The number average molecular weight of the polyester copolymer was determined by GPC analysis. In addition, as analysis conditions, the detection wavelength was 254 nm, tetrahydrofuran was used as a solvent, and it was determined by polystyrene conversion.

(3) Composition of polyester copolymer Using an NMR measuring apparatus (manufactured by JEOL Ltd., “JNM-LA400 type”), ¹ H-NMR measurement was performed, and the composition was determined from the peak intensity of each copolymer component. . Note that deuterated trifluoroacetic acid was used as a measurement solvent.

(4) Glass transition point (Tg) of polyester copolymer
According to JIS-K 7121, from a chart heated at 10 ° C./min from 20 ° C. to 120 ° C. using an input-compensated differential scanning calorimeter (“Diamond DSC”, manufactured by Perkin Elmer) (Tg) was read.

(5) Solubility of polyester copolymer The obtained polyester copolymer was mixed with toluene and methyl ethyl ketone so that the solid content concentration was 30% by mass [(toluene) / (methyl ethyl ketone) = 8/2. , Mass ratio] was observed visually and evaluated according to the following criteria.
○: Most of the polyester copolymer was dissolved.
Δ: Part of the polyester copolymer was dissolved.
X: The polyester copolymer was hardly dissolved.
Those with ○ or Δ were judged to have practical solubility. Those with x were inferior in solubility and difficult to form into a coating film, and therefore judged not to have practicality.

(6) Flexibility when formed into a coating (bending test)
The polyester copolymer is dissolved in a mixed solvent of toluene and methyl ethyl ketone [(toluene) / (methyl ethyl ketone) = 8/2, mass ratio] so that the solid content concentration is 30% by mass to obtain a solution. It was. 11.0 g of a curing agent was added to the solution to obtain a resin composition. The resin composition was applied to a polyethylene terephthalate (PET) film having a thickness of 38 μm using a desktop coating apparatus (Yasuda Seiki Co., Ltd., film applicator No. 542-AB type, bar coater apparatus). Then, the coating film whose thickness at the time of drying is 25 micrometers was formed by heat-processing at 100 degreeC for 30 second (s). This coating film was aged at 50 ° C. for 96 hours and then bent in the 180 ° direction. And the state of the coating film at the time of opening was observed visually. Evaluation was made according to the following criteria.
(Double-circle): The coating film was not cracked and the trace which bent was not left.
○: The coating film was not cracked, but a few traces were left.
(Triangle | delta): Although the coating film was not cracked, the folded mark remained strongly.
X: The coating film was cracked.

(7) Heat resistance when formed into a coating (hot pressure test)
The polyester copolymer is dissolved in a mixed solvent of toluene and methyl ethyl ketone [(toluene) / (methyl ethyl ketone) = 8/2, mass ratio] so that the solid content concentration is 30% by mass to obtain a solution. It was. 11.0 g of a curing agent was added to the solution to obtain a resin composition. The resin composition was applied to a copper plate using a desktop coating device (manufactured by Yasuda Seiki Co., Ltd., film applicator No. 542-AB type, bar coater device). Thereafter, a heat treatment was performed at 100 ° C. for 30 seconds to form a coating film having a dry thickness of 25 μm and a coating area of 10000 mm ² . After this coating film was aged at 50 ° C. × 96 hours or 50 ° C. × 144 hours, a copper plate was further placed on the coating film, and hot pressed at a temperature of 120 ° C. and a pressure of 0.1 MPa with a heat press machine. The amount of the coating film flowing out during hot pressing (that is, the amount of protrusion from the copper plate) was visually observed. Evaluation was made according to the following criteria.
A: Almost no coating flowed out and 95% or more of the coated area remained.
○: The coating film flowed out, and 85 to less than 95% of the coated area remained.
(Triangle | delta): The coating film flowed out and 50-85% of the application area remained.
X: Most of the coating film flowed out and remained less than 50% of the coated area.

(8) Comprehensive evaluation (circle): There is no evaluation of x in the evaluation result of said (5)-(7).
X: Among the evaluation results (5) to (7), there is one or more evaluations of x.

(Preparation of polyester resin)
Preparation Example 1
57 g (31 mol%) of terephthalic acid, 64 g (35 mol%) of isophthalic acid, 76 g (34 mol%) of sebacic acid, 46 g (67 mol%) of ethylene glycol, 78 g (68 mol%) of neopentyl glycol, and 0.4% of tetrabutyl titanate as a polymerization catalyst. 1 g was charged into the reactor, and the inside of the system was replaced with nitrogen. And while stirring these raw materials at 1000 rpm, the reactor was heated at 245 ° C. and melted. After the temperature in the reactor reached 245 ° C., the esterification reaction was allowed to proceed for 3 hours. After 3 hours, the temperature in the system was 240 ° C., and the system was depressurized. After the inside of the system reached a high vacuum (pressure: 0.1 to 10 ⁻⁵ Pa), a polymerization reaction was further performed for 3.0 hours to obtain a polyester resin A.

Preparation Examples 2-15
Polyester resins B to O were obtained in the same manner as in Preparation Example 1 except that the polymerization reaction time was changed as shown in Table 1. Table 1 shows the monomer charge composition and the polymerization reaction time in the polyester resins obtained in Preparation Examples 1 to 15. In addition, adjustment examples 2 and 15 indicate that the polymerization reaction time is 0 hour and the polymerization reaction after the esterification reaction is not performed.

In addition, the abbreviation in Table 1 and Table 2 mentioned later shows the following, respectively.
TPA: terephthalic acid IPA: isophthalic acid SEA: sebacic acid ADA: adipic acid EG: ethylene glycol PG: propylene glycol NPG: neopentyl glycol BAEO: bisphenol A ethylene oxide adduct PTMG1000: polytetramethylene glycol

II: 4- (2,5-Dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride III represented by the above formula (II): III) 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride IV: 3,3 ′, 4 represented by the above formula (IV) 4,4′-benzophenonetetracarboxylic dianhydride V: 4,4′-biphthalic anhydride VI represented by the above formula (V) VI: 3,3 ′, 4,4′-formula represented by the above formula (VI) Diphenylsulfonetetracarboxylic dianhydride VII: 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride VIII represented by the above formula (VII): 4,4′-oxydiphthalic acid represented by the above formula (VIII) Anhydride IX: 1,2,4,5-cyclohexanetetracarboxylic Dianhydride X: pyromellitic anhydride MDI: 4,4'- diphenylmethane diisocyanate (Tokyo Chemical Industry Co., Ltd., reagent, molecular weight 250.27)
HDI: Hexamethylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd., reagent, molecular weight 168.20)
IPDI: Isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd., reagent, molecular weight 222.29)
HDI3: trimer of hexamethylene diisocyanate (Asahi Kasei Chemicals, "Duranate TPA100", molecular weight 504)
EP: Epoxy resin (manufactured by Adeka, “EP-4100”, epoxy equivalent 190 g / eq)
OX: 2,2 ′-(1,3-phenylene) bis-2-oxazoline (manufactured by Tokyo Chemical Industry Co., Ltd., reagent, molecular weight 216.24)

In addition, 1,2,4,5-cyclohexanetetracarboxylic dianhydride is an aliphatic tetracarboxylic anhydride and does not have an aromatic ring. This is shown by the following formula (iv).

Example 1
Nitrogen was sealed in the reaction system to normal pressure, and polyester resin A and 5 g (2.4 mol%) of 4,4′-biphthalic anhydride were added. Subsequently, the temperature in the system was set to 240 ° C., and the reaction was further performed for 1 hour to obtain the polyester copolymer of the present invention. The obtained polyester copolymer is dissolved in a mixed solvent of toluene and methyl ethyl ketone [(toluene) / (methyl ethyl ketone) = 8/2, mass ratio] so that the solid content concentration thereof is 30% by mass, and a curing agent. As a result, 11.0 g (equal to the amount of terminal carboxyl groups) of 4,4′-diphenylmethane diisocyanate was added to obtain a resin composition of the present invention. From the obtained resin composition, coating films were formed on the PET film and the copper plate, respectively, by the methods (6) and (7) in the above evaluation method.
The evaluation results of Example 1 are shown in Table 2.

Examples 2-30 and Comparative Examples 1-4
The same operation as Example 1 except having changed the kind of polyester resin to be used, the kind and addition amount of the compound which has two acid anhydride groups, and the kind of hardening | curing agent as shown in Tables 2-4. To obtain a resin composition. About the obtained resin composition, the resin characteristic and the coating-film performance were evaluated. The results are shown in Tables 2-4.

  As is clear from Tables 2 to 4, the resin compositions obtained in Examples 1 to 30 were excellent in flexibility and heat resistance when used as coating films.

  The resin composition obtained in Example 2 had room for improvement in flexibility due to the slightly low molecular weight of the polyester copolymer contained therein, but was sufficiently durable for practical use. It was.

  The resin composition obtained in Example 6 was slightly inferior in solubility because the molecular weight of the polyester copolymer contained was somewhat high, and left room for improvement in ease of coating, but sufficient Can withstand practical use.

  The resin composition obtained in Example 7 has a slightly high molecular weight of the polyester copolymer contained, and the amount of tetracarboxylic dianhydride necessary for sealing the end of the polyester copolymer is small. For this reason, the crosslink density was reduced and there was room for improvement in heat resistance, but it was sufficiently able to withstand actual use.

  The resin compositions obtained in Examples 8 and 9 left room for improvement in heat resistance due to the skeleton of tetracarboxylic dianhydride introduced into the contained polyester copolymer. However, it was sufficiently practical.

  In the resin composition obtained in Example 14, the amount of tetracarboxylic dianhydride used in the polyester copolymer contained was less than 1 mol%. Although there was room for improvement in flexibility, it was sufficiently practical.

  The resin composition obtained in Example 17 was presumed that the polyester resin was plasticized because of the large amount of tetracarboxylic dianhydride introduced in the polyester copolymer contained, and there was room for improvement in heat resistance. Although it was left, it was enough to withstand practical use.

  The resin composition obtained in Comparative Example 1 was inferior in heat resistance because the number average molecular weight of the polyester copolymer contained was more than 50000.

  The resin compositions obtained in Comparative Examples 2 and 3 were flexible because a compound having two acid anhydride groups other than those defined in the present invention was introduced in the contained polyester copolymer. And it was inferior to heat resistance.

  The resin composition obtained in Comparative Example 4 was inferior in flexibility because the number average molecular weight of the polyester copolymer contained was too small.

Claims (6)

A resin composition comprising a polyester copolymer and a curing agent, wherein the polyester copolymer has a polyester polymer containing a polyvalent carboxylic acid component and a glycol component as a main chain, and the end of the polyester polymer is represented by the following formula: One carboxyl group and one acid anhydride group at the end are sealed with a tetracarboxylic dianhydride represented by any one of (I), formula (II), and formula (III) And a number average molecular weight of 1,000 to 50,000.

In the above formula (I), X is a direct bond, or one or more selected from a group represented by a carbonyl group, an oxo group, a sulfonyl group, and —C (CF ₃ ) ₂ —. Indicates a group.

  The resin composition according to claim 1, wherein the polyester copolymer has a glass transition point of -20 to 75 ° C.   The polyester copolymer is sealed with tetracarboxylic dianhydride in an amount of 1 to 18 mol% based on the total amount of the polyvalent carboxylic acid component contained in the polyester copolymer. The resin composition according to claim 1 or 2.   The resin composition according to any one of claims 1 to 3, wherein the curing agent is 4,4'-diphenylmethane diisocyanate. It is a method of manufacturing the resin composition of any one of Claims 1-4, Comprising: The manufacturing method of the resin composition characterized by having the process of following (i) and (ii) in this order.
(I) After obtaining a polyester resin as a main chain by polymerizing polyvalent carboxylic acid and glycol, the above formula (I), formula (II) and formula (III) based on the amount of terminal hydroxyl groups of the polyester resin A tetracarboxylic dianhydride represented by any of the above is added at a ratio of 1.0 to 3.0 equivalents, and a polyester copolymer in which one carboxyl group and one acid anhydride group are introduced at the terminal is provided. A step of obtaining a polymer.
(Ii) A step of dissolving the polyester copolymer obtained in (i) in a solvent and then adding a curing agent to obtain a resin composition.   The coating film formed from the resin composition of any one of Claims 1-4.