JP2016138057A - Acid alkylating agent, method for generating acid alkylation product, resin composition and polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an acid alkylating agent which causes less generation of irritant gas and suppresses generation of a gel component; a method for generating an acid alkylation product; a resin composition; and a polyester film.SOLUTION: There are provided: an acid alkylation agent represented by the following general formula (1) obtained by subjecting a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphate group and a phenolic hydroxyl group to acid alkylation; a method for generating an acid alkylation product; a resin composition; and a polyester film. Q represents a group for bonding with a -C=N- site to form a 5 to 12- membered nitrogen-containing heterocycle; Rto Reach independently represents a hydrogen atom, an alkyl group or an aryl group; and Rto Rmay be bonded each other to form a ring.SELECTED DRAWING: None

Description

  The present invention relates to an acid alkylating agent, a method for producing an acid alkylated product, a resin composition, and a polyester film.

  Polymers are widely used in various fields, both indoors and outdoors. For example, when a polymer is heated to a high temperature during molding or used exclusively for products installed outdoors, the polymer should be exposed to a harsh environment such as a high temperature environment or a high humidity environment for a long period of time. There is.

  On the other hand, a trace amount of acid may be present in the polymer. When a trace amount of acid is present in the polymer, deterioration of the polymer may be promoted when the polymer is exposed to high-temperature or high-humidity environmental conditions as described above. Specifically, it may cause thermal degradation of the polymer at the time of molding, and even after molding, depending on the usage environment, it may be deteriorated by promoting hydrolysis of the polymer by being exposed to a humid heat environment for a long time. . The presence of a small amount of acid similarly causes deterioration of the polymer regardless of whether the acid itself is bonded to the polymer chain or the acid is mixed.

  In recent years, for example, a polymer film typified by a polyester film such as polyethylene terephthalate has been used as a back sheet disposed for protecting the back surface of a solar cell. For example, polyester is known to have poor hydrolysis resistance and easily become brittle because a carboxylic acid group present at the end of a polymer chain promotes hydrolysis. In order to suppress this hydrolysis, a method of sealing a carboxylic acid group remaining at the end of a polymer chain of polyester is known, and a carbodiimide compound and a cyclic imino ether compound are known as sealing agents.

  Specifically, a polyester film containing an oxazoline compound and an oxazine compound which are carbodiimide compounds or cyclic imino ether compounds is disclosed (for example, see Patent Document 1). In this document, it is said that the dimensional stability and hydrolysis resistance of polyester are improved by reacting a carbodiimide compound and a cyclic imino ether compound with a carboxylic acid group present at the end of the polyester.

JP 2010-031174 A

  However, the carbodiimide compound has a problem that free isocyanate is volatilized as an irritating gas after reacting with a carboxylic acid group.

Cyclic imino ether compounds are known to self-polymerize. When the cyclic imino ether compound is examined, the self-polymerized cyclic imino ether compound is likely to exist as a gel component in the resin, and the gel component increases the viscosity of the resin. The presence of the gel component also generates gel-like defects when the film is formed, and is a factor that impairs the surface state of the formed film (hereinafter also simply referred to as “plane shape”). .
Here, the gel-like irregularity refers to a convex abnormal part visually recognized as a bright spot on a smooth and uniform film surface, and the major axis when observed from the film surface is about several tens of μm to several mm. In many cases.

  The present invention has been made in view of the above, and includes an acid alkylating agent and an acid alkylated product that suppress generation of irritating gas and suppress generation of a gel component (for example, a gel component in a resin). An object is to provide a production method, a resin composition in which deterioration due to acidic groups and an increase in viscosity are suppressed, and a polyester film having a small number of granular materials and an excellent surface shape.

Specific means for achieving the object includes the following embodiments.
<1> Acid alkylating agent represented by the following general formula (1), which acid-alkylates a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group It is.

In the general formula (1), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring.
<2> Q is the acid alkylating agent according to <1>, which represents a group that combines with the —C═N— moiety to form a nitrogen-containing 6-membered ring.
<3> Q represents a group that forms a condensed ring of a triazine ring or a nitrogen-containing 6-membered ring and a benzene ring by bonding to the —C═N— moiety, R ¹¹ represents a hydrogen atom, R ¹² and R ¹³ are acid alkylating agents according to <1> or <2>, each independently representing a hydrogen atom or an alkyl group.
<4> Any one of <1> to <3>, wherein the nitrogen-containing heterocycle containing Q and a —C═N— moiety is a quinazoline ring which is a 10-membered ring in which a benzene ring and a pyrimidine ring are condensed. The acid alkylating agent described in 1.
<5> Acid alkylating agent represented by the following general formula (2), which acid-alkylates a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group It is.

In General Formula (2), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. L ¹ represents a p-valent group whose bond terminal to Q is an alkylene moiety, an arylene moiety, or an alkyleneoxy moiety. p represents an integer of 2 to 4. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring.

<6> The acid alkylating agent according to any one of <1> to <5>, and at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. This is a method for producing an acid alkylated product, in which an acid alkylated product is produced by reacting a compound with a compound in a temperature range of 100 ° C to 350 ° C.
<7> The acid alkylating agent according to any one of <1> to <5>, and at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. And a resin composition.
<8> The resin composition according to <7>, wherein the resin is polyester.
<9> The resin composition according to <8>, obtained by mixing an acid alkylating agent and polyester in a molten state.
<10> A polyester film formed using the resin composition according to <8> or <9>.

ADVANTAGE OF THE INVENTION According to this invention, the production | generation method of the acid alkylating agent which suppresses generation | occurrence | production of an irritating gas and suppresses the production | generation of a gel component (for example, gel component in resin) and an acid alkylation thing is provided.
Moreover, according to this invention, the resin composition in which deterioration derived from an acidic group and a viscosity increase were suppressed is provided.
Furthermore, according to the present invention, there is provided a polyester film having a small number of granular materials and an excellent surface shape.

Hereinafter, the acid alkylating agent of the present invention and the method for producing the acid alkylated product of the present invention, the resin composition, and the polyester film using the acid alkylating agent will be described in detail.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

<Acid alkylating agent>
The acid alkylating agent of the present invention is represented by the following general formula (1), and is a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group (hereinafter referred to as “acidic alkylating agent”). , Simply referred to as “compound having an acidic group”).

The polymer may be exposed to harsh environmental conditions, such as high temperature environments or high humidity environments, for example, during molding or use, for an extended period of time. Such a situation tends to cause deterioration of the polymer. In particular, when an acidic group is present in the polymer, deterioration of the polymer may be promoted due to the acidic group. For example, polyester often contains a carboxylic acid group, and embrittlement associated with hydrolysis may be promoted due to the carboxylic acid group. In order to prevent embrittlement of a polymer derived from a carboxylic acid group, conventionally, a carbodiimide compound or a cyclic imino ether compound as described in Patent Document 1 is used, and the terminal carboxylic acid group is sealed to prevent hydrolysis. Techniques for improving the quality have been proposed. However, the carbodiimide compound described in Patent Document 1 generates an irritating gas with the sealing of the carboxylic acid group, and the cyclic imino ether compound described in Patent Document 1 increases the viscosity of the polymer due to self-polymerization. There is a concern that the film surface condition is likely to deteriorate.
On the other hand, the deterioration of the polymer is not limited to the case where the acidic group is bonded to the polymer chain, but may be caused by mixing the acid component into the polymer for various reasons in the raw material and the production process. In this case, there is a concern about deterioration due to the inclusion of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, or a phenolic hydroxyl group as an acidic group, and in particular in applications where high durability is required, a carboxylic acid group, a sulfonic acid group , Phosphoric acid groups, or phenolic hydroxyl groups are major factors that promote polymer degradation.
From such a situation, as an alkylating agent different from the carbodiimide compound and the cyclic iminoether compound, a ring structure containing an —N═C—O— moiety such as an oxazoline ring is not formed in the structure, and —N An iminoether compound in which an alkyl is bonded to an oxygen atom of a C—O— moiety and a ring structure including a —N═C— moiety among —N═C—O— moieties is not self-polymerized. They obtained knowledge that they are effective in preventing the deterioration of the polymer. The iminoether compound having a structural part in which an alkoxy moiety is bonded to a ring structure containing a —N═C— moiety alkylates a compound having an acidic group, which deteriorates the compound while maintaining the working environment and resin performance. As a reaction to prevent, it is considered that there is an action not seen in the conventional sealing reaction.
Based on such knowledge, in the present invention, an acid alkylating agent represented by the general formula (1) which is an imino ether compound is used to alkylate and seal an acidic group. Thereby, it becomes difficult to volatilize the irritating gas and the generation of the gel component, and the deterioration of the compound having an acidic group can be suppressed. In particular, embrittlement and thickening of a resin having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group can be effectively suppressed. In addition, when the film is formed, a film excellent in the film surface can be obtained with few granular materials present on the film surface.

Acid alkylation refers to a reaction in which a hydrogen atom of an acidic group in a compound having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group is substituted with an alkyl group. The component used is called an acid alkylating agent. Specifically, for example, as shown in Scheme 1 or Scheme 2 below, between the “N═C-alkoxy” moiety and the terminal carboxylic acid group (—COOH) or terminal sulfonic acid group (—SO ₃ H). Then, the alkylation reaction proceeds to produce an acid alkylated product.
In Scheme 1, an ester compound which is an example of an acid alkylated product is produced by reacting with a carboxylic acid group, and the acid alkylating agent (iminoether compound) represented by the general formula (1) is an amide compound. It will be contained in the resin composition. Further, in Scheme 2, an acid alkylated product is generated by reacting with a sulfonic acid group, and the acid alkylating agent (iminoether compound) represented by the general formula (1) is an amide compound and is contained in the resin composition. Will be.

The imino ether compound which is an acid alkylating agent of the present invention is represented by the following general formula (1).

In general formula (1), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring.

  As group which couple | bonds with Q of General formula (1), ie, -C = N- site | part, and forms a 5-12 membered nitrogen-containing heterocyclic ring, C1-C1 which may have a substituent, for example 10 alkylene group, C1-C10 alkenylene group which may have a substituent, C1-C10 alkyleneoxy group which may have a substituent, These are mentioned. Examples of the substituent when the group represented by Q is substituted include an alkyl group, an aryl group, an alkoxy group, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group. An alkyl group or an aryl group is preferable, and an aryl group (particularly a phenyl group) is more preferable.

Q is a group consisting of the above-mentioned alkylene group, alkenylene group, alkyleneoxy group and the like, and —N═CH—, —O—, —SO ₂ —, —S—, and —SO— as a partial structure. And at least one selected from divalent groups.

Preferred Q is, for example, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted n-butylene, substituted or unsubstituted —C ₆ H ₄ —N═CH— and the like.

In the general formula (1), as a nitrogen-containing heterocyclic group bonded to the oxygen atom of “OCR ¹¹ R ¹² R ¹³ ” (that is, a group derived from a nitrogen-containing heterocyclic ring containing Q and a —C═N— moiety) Includes a residue in which one hydrogen atom bonded to the carbon atom of the —C═N— site in a nitrogen-containing compound containing a —C═N— site is removed.

  A 5-membered to 12-membered nitrogen-containing heterocyclic ring formed by combining Q and —C═N— moiety (hereinafter, also referred to as “nitrogen-containing heterocyclic ring containing Q and —C═N— moiety”). Any of monocyclic and condensed rings may be used, and a 6-membered to 10-membered monocyclic or condensed nitrogen-containing heterocyclic ring is preferable. Among them, the nitrogen-containing heterocyclic ring containing Q and the —C═N— moiety is preferably a 6-membered nitrogen-containing heterocyclic ring in the case of a single ring, and a 10-membered nitrogen-containing heterocyclic ring in the case of a condensed ring. .

  Among them, the nitrogen-containing heterocyclic ring containing Q and the —C═N— moiety is preferably a triazine ring or a condensed ring of a nitrogen-containing 6-membered ring and a benzene ring, and the triazine ring or the pyrimidine ring and the benzene ring are condensed. A quinazoline ring that is a 10-membered ring is more preferred.

In General Formula (1), R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent.

The alkyl group of R ¹¹ , R ¹² , and R ¹³ is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms. The alkyl groups of R ¹¹ , R ¹² , and R ¹³ may be linear or branched. Moreover, the alkyl group of R ¹¹ , R ¹² , and R ¹³ may be a cycloalkyl group.

Examples of alkyl groups for R ¹¹ , R ¹² , and R ¹³ include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, iso- Examples thereof include a butyl group, an n-pentyl group, a sec-pentyl group, an iso-pentyl group, an n-hexyl group, a sec-hexyl group, an iso-hexyl group, and a cyclohexyl group. Among these, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an iso-butyl group, and a cyclohexyl group are more preferable.
The alkyl groups of R ¹¹ , R ¹² , and R ¹³ may further have a substituent. In addition, carbon number of the alkyl group of R < ¹¹ >, R < ¹² > and R < ¹³ > shows carbon number which does not contain a substituent. Examples of the substituent of the alkyl group include an aryl group, an alkoxy group, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

The aryl group of R ¹¹ , R ¹² , and R ¹³ is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms. Examples of the aryl group of R ¹¹ , R ¹² and R ¹³ include a phenyl group and a naphthyl group, and among them, a phenyl group is preferable.
The aryl groups of R ¹¹ , R ¹² , and R ¹³ may further have a substituent. In addition, carbon number of the aryl group of R < ¹¹ >, R < ¹² > and R < ¹³ > shows carbon number which does not contain a substituent. The substituent of the aryl group is not particularly limited as long as the reaction between the N═C—O site and the acidic group can proceed, and is an alkyl group, aryl group, alkoxy group, halogen atom, nitro group, amide group, hydroxyl group. Examples include groups, ester groups, ether groups, aldehyde groups and the like.

R ¹¹ , R ¹² , and R ¹³ are preferably a hydrogen atom or an alkyl group that may have a substituent in terms of reaction efficiency. Among them, R ¹¹ is preferably a hydrogen atom, and R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group that may have a substituent. In this case, the nitrogen-containing heterocycle further containing Q and the —C═N— moiety is preferably a triazine ring or a condensed ring of a nitrogen-containing 6-membered ring and a benzene ring, more preferably a triazine ring or a pyrimidine ring. It is a quinazoline ring which is a 10-membered ring in which a benzene ring is condensed.

The acid alkylating agent of the present invention is more preferably an imino ether compound having a multimeric structure among the imino ether compounds represented by the general formula (1) in view of the reaction efficiency of acid alkylation. Specifically, an acid alkylating agent which is an imino ether compound multimer represented by the following general formula (2) is preferable. In this case, in the general formula (2), the substituent bonded to any one carbon atom (specific carbon atom) in Q of the general formula (1) is connected by detaching one hydrogen atom in the substituent. This represents a compound in which p is a group L, and p residues each including Q containing a specific carbon atom and “OCR ¹¹ R ¹² R ¹³ ” are linked via L.
L is an alkylene group or an arylene group when the substituent bonded to the specific carbon atom is, for example, an alkyl group or an aryl group.

  The imino ether compound multimer is preferably an imino ether compound represented by the following general formula (2).

In General Formula (2), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring. L ¹ is a p-valent group which is an alkylene moiety that may have a substituent, an arylene moiety that may have a substituent, or an alkyleneoxy moiety that may have a substituent, at the bonding end to Q. Represents. p represents an integer of 2 to 4. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring.

^{R 11, R 12, R 13} , and Q, ^R 11 in the general formula ^{(1), R 12, R} 13, and Q and have the same meanings, preferable embodiments thereof are also the same.
L ¹ is preferably an arylene moiety which may have a substituent, and more preferably a phenylene group, from the viewpoint of suppressing the volatilization of the molecule.

  In addition, the imino ether compound multimer is also preferably an imino ether compound represented by the following general formula (3).

In General Formula (3), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. L ² represents a p-valent group that is an alkylene moiety that may have a substituent at the terminal of the N═C—O moiety bonded to the oxygen atom. p represents an integer of 2 to 4.

Q is synonymous with Q in General formula (1), and its preferable aspect is also the same.
L ² represents a p-valent group that is an alkylene moiety that may have a substituent at the terminal of the N═C—O moiety bonded to the oxygen atom. That is, the p-valent group has an alkylene moiety at the terminal of the bond with the oxygen atom of the N═C—O moiety. The alkylene moiety of L ² may be a substituted alkylene moiety in which some or all of the hydrogen atoms are substituted with an alkyl group that may have a substituent or an aryl group that may have a substituent.
p is preferably 2 or 3 in that it is excellent in an acid alkylation reaction of an acidic group-containing compound with an acidic group iminoether compound.

Specific examples of L ² include an alkylene group.
L ² has an alkylene moiety at the bond terminal with the oxygen atom of the N═C—O moiety as described above, and has a partial structure of —SO ₂ —, —CO—, an alkylene group, an alkenylene group, an alkynylene. And a group having at least one linking group selected from the group consisting of a group, a phenylene group, a biphenylene group, a naphthylene group, -O-, -S-, and -SO-. The alkylene moiety, alkenylene moiety, alkynylene moiety, phenylene moiety, biphenylene moiety, and naphthylene moiety as the partial structure may be unsubstituted or may have a substituent.
Preferred L ² is, for example, substituted or unsubstituted ethylene, substituted or unsubstituted n-butylene, substituted or unsubstituted —CH ₂ —C (CH ₃ ) ₂ —CH ₂ —, substituted or unsubstituted —CH _{2 -C 6 H 4 -CH 2 -} , -C substituted or unsubstituted _{2 H 4 -CO-C 6 H} 4 -COO-C 2 H 4 -, and the like.

The molecular weight per iminoether (N═C—O) structure of the acid alkylating agent represented by the general formula (1) is preferably 1000 or less, more preferably 750 or less, and 500 or less. A range is further preferred. The lower limit of the molecular weight per iminoether structure is preferably 200. When the molecular weight per imino ether structure is within the above range, acid alkylation (acid sealing) of an acidic group can be effectively performed even with a small addition amount.
The molecular weight per iminoether structure represents the molecular weight obtained by dividing the molecular weight of the compound by the number of iminoether (N═C—O) structures in the compound.

  Specific examples of the acid alkylating agent (imino ether compound) represented by the general formula (1) are shown below. However, the present invention is not limited to these specific examples. “Me” represents a methyl group.

  An acid alkylating agent (imino ether compound) represented by the general formula (1), a compound having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group (for example, a resin); When the acidic group is acid-alkylated by reacting, the reaction temperature is preferably selected based on the melting point (Tm) of the compound having an acidic group. As reaction temperature, it can be set as the range of (Tm + 5) degreeC-(Tm + 100) degreeC, for example, The range of (Tm + 10) degreeC-(Tm + 80) degreeC is suitable. When the reaction temperature is (Tm + 5) ° C. or higher, the acid alkylation reaction proceeds well and gelation is effectively suppressed. Further, when the reaction temperature is (Tm + 100) ° C. or lower, the thermal decomposition of the compound having an acidic group is suppressed, and the hydrolysis resistance is excellent.

~ Synthesis of iminoether compounds ~
As a method for synthesizing an iminoether compound which is an acid alkylating agent represented by the general formula (1), there are a method in which an amide compound is converted to imidoyl chloride and reacted with an alkoxide, and a method in which an aniline compound and an orthoester compound are reacted. Are known. As a synthesis method, any method may be used, but a method of reacting an aniline compound and an ortho ester compound is preferable. An imino ether compound synthesized by a method of reacting an aniline compound and an ortho ester compound is preferable in that the hydrolysis resistance of the compound having a color and an acidic group is further improved. In the case of the method of reacting an aniline compound and an ortho ester compound, it is considered that this contributes to the absence of a colored product or a reagent that deteriorates hydrolysis resistance and the absence of a reaction product. Moreover, the method of reacting an aniline compound and an ortho ester compound is preferable also from the point which can synthesize | combine an imino ether compound in a short process.
For example, a resin composition comprising an acid alkylating agent represented by the general formula (1) and a resin having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group is prepared. In this case, the resin composition to which the imino ether compound synthesized by the method of reacting the aniline compound and the ortho ester compound is added has excellent hydrolysis resistance and color, so that it can be applied to various applications. For example, it is suitably used for a solar cell backsheet. When a back sheet for a solar cell is produced using a resin composition with little coloring, the power generation efficiency of the solar cell can be improved without reducing the reflectance of sunlight.

<Method for producing acid alkylated product>
The method for producing an acid alkylated product of the present invention comprises a compound having the acid alkylating agent of the present invention described above and at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. It is a method of producing an acid alkylated product by reacting (a compound having an acidic group) in a temperature range of 100 ° C to 350 ° C. Since acid alkylation of acidic groups is performed using the acid alkylating agent of the present invention, generation of irritating odor accompanying acid alkylation, and thickening or gelation when acid alkylated products are produced can be suppressed. .

  In the method for producing an acid alkylated product of the present invention, the acid alkylation (acid sealing) of an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group is carried out by a carboxylic acid group, a sulfonic acid group. , A compound having at least one acidic group selected from a phosphoric acid group and a phenolic hydroxyl group (for example, a resin) and an acid alkylating agent represented by the general formula (1) are mixed and reacted in a molten state. Is done.

The reaction temperature during the reaction is set to a temperature range of 100 ° C to 350 ° C. When the reaction temperature is in the range of 100 ° C. to 350 ° C., the acid alkylation reaction of the acidic group-containing compound with the acidic group imino ether compound proceeds efficiently. That is, when the reaction temperature is 100 ° C. or higher, the acid alkylation reaction proceeds more favorably and becomes difficult to accompany gelation. Therefore, when a resin is used as the compound having an acidic group, a good planar film can be obtained. In addition, when the reaction temperature is 350 ° C. or lower, thermal decomposition of the compound having an acidic group is suppressed, and the hydrolysis resistance is excellent. This is particularly effective when the compound having an acidic group is a resin.
Specifically, when a resin having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group is used as the compound having an acidic group, the following temperature range can be set, for example. .
In the case of polyethylene terephthalate, the reaction temperature is preferably 265 ° C to 350 ° C, and more preferably 270 ° C to 340 ° C. In the case of polybutylene terephthalate, it is preferably 230 ° C to 325 ° C, more preferably 235 ° C to 305 ° C. In the case of polyethylene-2,6-naphthalate, 270 ° C to 350 ° C is preferable, and 275 ° C to 345 ° C is more preferable.
Moreover, since it is preferable to react at the time of resin mixing as reaction time, 1 minute-20 minutes are preferable, 1 minute-10 minutes are more preferable, and 1 minute-5 minutes are still more preferable.

  As shown in the reaction scheme described in the description of the acid alkylating agent of the present invention, when the imino ether compound and the compound having an acidic group are reacted in a temperature range of 100 ° C. to 350 ° C., the imino ether group and An acid alkylated product is produced by reacting with an acidic group and alkylating the acidic group. The acid alkylating agent represented by the general formula (1) reacts with an acidic group to become an amide compound.

  The reaction rate between the acid alkylating agent represented by the general formula (1) and the compound having an acidic group can be in the range of 0.1% to 99%, and more preferably 1% to 90%. Preferably, 2% to 80% is more preferable. When the reaction rate is within the above range, the hydrolysis resistance of the compound having an acidic group (particularly a resin) can be further improved. Further, when a resin is used as the compound having an acidic group, in the resin composition containing the acid alkylating agent represented by the general formula (1) and the resin, the generated amide compound bleeds out from the resin composition. The phenomenon is suppressed, and the generation of particulates on the film surface when the film is formed using the resin composition is suppressed, and as a result, the film surface is excellent.

Conventionally, for example, it is known to carry out acid alkylation by reacting a carboxylic acid group which is an acidic group with a cyclic imino ether such as oxazoline or oxazine. When a cyclic imino ether having a ring structure including an N═C—O moiety is used, a self-condensation proceeds as a side reaction simultaneously with a ring-opening reaction as shown in the following scheme. The self-condensation accompanying the ring opening is considered to occur due to the high nucleophilicity of the amide group of the alkylamide generated by the ring opening reaction.
In contrast, in the present invention, acid alkylation is performed using an acid alkylating agent represented by the general formula (1). It does not have a ring structure such as oxazoline or the like, that is, a ring structure containing an N═C—O moiety, has an “N═C-alkoxy” moiety, and —N═C—O— moiety among —N— It is considered that an imino ether compound having a ring structure containing a ═C— moiety does not cause self-condensation because the nucleophilicity of the aromatic amide obtained by the acid alkylation reaction is not high. Thereby, the phenomenon that an imino ether compound gels is suppressed.

<Resin composition>
The resin composition of the present invention comprises the acid alkylating agent of the present invention described above and a resin having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. It may contain and may contain other ingredients as needed.

Details of the acid alkylating agent of the present invention are as described above, and the same applies to preferred embodiments.
As content of the acid alkylating agent in a resin composition, 0.05 mass%-5 mass% are preferable with respect to the total solid of a resin composition, and 0.1 mass%-4 mass% are more preferable. 0.1% by mass to 2% by mass is more preferable, and 0.4% by mass to 2% by mass is particularly preferable. When the content of the acid alkylating agent is 0.05% by mass or more, the acid alkylating reaction of the acidic group proceeds well. When the content of the acid alkylating agent is 5% by mass or less, it is advantageous in terms of resin production cost.

  The resin composition of the present invention may contain a compound capable of acid alkylation other than the acid alkylating agent of the present invention, depending on the purpose and case. Specifically, the acid alkylating agent of the present invention may be used in combination with, for example, a carbodiimide compound, a ketenimine compound, an epoxy compound, or an oxazoline compound as long as the effects of the present invention are not hindered. In this case, the content of the acid alkylating agent of the present invention relative to the total mass of the organic compound other than the resin contained in the resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, and 90% by mass. The above is more preferable.

The resin is not particularly limited as long as it has an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. In the present invention, a resin having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group includes a carboxylic acid group in a chain structure (so-called polymer chain) in the molecule, Resin having an acidic group selected from a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group, and a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and phenolic as a polymerization catalyst or an additive in the resin, for example. A resin having an acidic group selected from a hydroxyl group and a resin having an acidic group in the resin is included.
Therefore, the resin in the present invention includes polyester, polyolefin, polyamide, polyurethane, (meth) acrylic resin, fluororesin, etc., and mixed resins thereof. Preferably, polyester and polyester and other resins are used. It is a mixed resin. For example, a mixed resin obtained by blending a small amount of other types of resin such as polyimide with polyester may be used.
Polyester is used for a solar cell backsheet, for example. Resins used for solar cell backsheets are required to have excellent wet heat resistance (particularly hydrolysis resistance) over a long period of time. In addition to carboxylic acid groups, polyesters may have sulfonic acid groups, phosphoric acid groups, and phenolic hydroxyl groups due to contamination from raw materials used, polymerization catalysts, and the like. By acid alkylating these acidic groups using the acid alkylating agent of the present invention, a polyester having a high wet heat resistance (ie, hydrolysis resistance) can be obtained.
The resin composition of the present invention is obtained by mixing the acid alkylating agent of the present invention and a resin having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group in a molten state. It is preferable that the acid group is acid alkylated (acid-sealed) by the reaction between them.

Although there is no restriction | limiting in particular about said polyester, A saturated polyester is preferable. Saturated polyester provides a polyester film having superior mechanical strength compared to unsaturated polyester.
The polyester has an ester (—COO—) bond or an oxycarbonyl (—OCO—) bond in one molecular chain, and may be either a homopolymer or a copolymer. The polyester is a hydroxyl group (—OH), a carboxyl group (—COOH), or a group in which these are protected (—ORX group, —COORX group; RX = any substituent such as an alkyl group), A linear saturated polyester synthesized from a group dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof is preferred.
The linear saturated polyester is described in, for example, JP2009-155479A and JP2010-235824A. Examples of linear saturated polyesters include polyethylene terephthalate (PET), polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene-2,6-naphthalate, and mechanical properties. From the viewpoint of balance of cost and polyethylene, polyethylene terephthalate is preferable. Moreover, as polyester, you may use crystalline polyester which can form anisotropy at the time of melt film forming.

  The molecular weight of the polyester is preferably 5,000 to 100,000, more preferably 8,000 to 80,000 in terms of weight average molecular weight (Mw), from the viewpoint of heat resistance and viscosity, and 12,000. It is particularly preferred that it is ˜60,000.

The weight average molecular weight of the polyester is a value measured as a converted value of polymethyl methacrylate (PMMA) using gel permeation chromatography (GPC). The calibration curves are “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, “A-2500”, “A-1000”, “n-fluoropropyl”. It was prepared from 8 samples of “Bensen”. The measurement conditions are as follows.
<Condition>
・ GPC: HLC-8220 GPC [manufactured by Tosoh Corporation]
Column: TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, TSKgeL SuperHZ2000 (all manufactured by Tosoh Corporation)
・ Mobile phase solvent: Hexafluoroisopropanol ・ Standard sample: Polymethyl methacrylate (PMMA)
Sample concentration: 0.45% by mass
・ Flow rate: 0.35 ml / min
-Column temperature: 40 ° C
Sample injection volume: 10 μl
・ Uses differential refractometer (RI) detector

Polyester which is a preferable resin can be synthesized by a known polycondensation method or ring-opening polymerization method, and may be either a transesterification reaction or a reaction by direct polymerization.
When the polyester is a polymer obtained by a condensation reaction mainly comprising an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, an aromatic dibasic acid or an ester thereof is formed It can synthesize | combine by carrying out a polycondensation reaction, after making an esterification reaction and a diol or its ester-forming derivative react with esterification or transesterification. It is preferable that the component derived from the carboxylic acid of the polyester is a component derived from an aromatic dibasic acid or an ester-forming derivative thereof. Moreover, the carboxylic acid value and intrinsic viscosity of the polyester can be controlled by selecting the raw material and reaction conditions.

From the viewpoint of effectively advancing esterification reaction or transesterification reaction and polycondensation reaction, it is preferable to add a polymerization catalyst during the reaction.
The polymerization catalyst is preferably selected from aluminum-based compounds, antimony-based compounds, germanium-based compounds, and titanium-based compounds from the viewpoint of keeping the carboxylic acid group in a small range of a predetermined amount or less, particularly titanium-based compounds. Is preferred. In the case of using a titanium-based compound, a mode in which the titanium-based compound is added as a polymerization catalyst in a range of 1 ppm to 30 ppm, more preferably 3 ppm to 15 ppm, and polymerization is preferable. When the amount of the titanium compound used is within the above range, the carboxylic acid group of the polyester is small, and the hydrolysis resistance can be kept low.
The synthesis of polyester using a titanium compound is, for example, Japanese Patent Publication No. 8-301198, Japanese Patent No. 2543624, Japanese Patent No. 3335683, Japanese Patent No. 3717380, Japanese Patent No. 397756, and Japanese Patent No. 396226. , Japanese Patent No. 3997866, Japanese Patent No. 3996871, Japanese Patent No. 40000867, Japanese Patent No. 4053837, Japanese Patent No. 4127119, Japanese Patent No. 4134710, Japanese Patent No. 4159154, Japanese Patent No. 4269704, Patent The method described in Japanese Patent No. 4313538 can be applied.

The polyester is preferably solid-phase polymerized after polymerization. The solid-phase polymerization may be a continuous method (a method in which a tower is filled with a resin, and after slowly flowing for a predetermined time while heating, and then sent out), or a batch method (a resin is put into a container, A method of heating for a predetermined time) may be used. The solid phase polymerization temperature is preferably 170 ° C to 240 ° C, more preferably 180 ° C to 230 ° C. The solid phase polymerization time is preferably 5 hours to 100 hours, more preferably 10 hours to 75 hours. The solid phase polymerization is preferably performed in a vacuum or in a nitrogen atmosphere.
For solid phase polymerization, Japanese Patent No. 2621563, Japanese Patent No. 3121876, Japanese Patent No. 3136774, Japanese Patent No. 3603585, Japanese Patent No. 3616522, Japanese Patent No. 3617340, Japanese Patent No. 3680523, Japanese Patent No. 3680523 are disclosed. The methods described in Japanese Patent No. 3717392 and Japanese Patent No. 4167159 can be applied.

Further, the content ratio of the acid alkylating agent to the resin having an acidic group in the resin composition (acid alkylating agent / resin; mass%) is preferably 0.05% by mass to 5% by mass, 0.1% More preferably, 4% by mass to 4% by mass is more preferable, 0.1% by mass to 2% by mass is further preferable, and 0.4% by mass to 2% by mass is particularly preferable. The case where the content rate of the acid alkylating agent with respect to resin which has an acidic group is 1 mass% is mentioned, for example.
When the content ratio of the acid alkylating agent is 0.05% by mass or more, the acid alkylating agent is not decreased too much, so that the hydrolysis resistance of the resin composition and the film thereof is improved. When the content ratio of the acid alkylating agent is 5% by mass or less, the amount of the acid alkylating agent is not excessive, so that the gelation of the resin composition is suppressed and the film thickness uniformity when the film is formed is improved. be able to. Moreover, the hydrolysis resistance of a resin composition and its film can be effectively improved because the content rate of an acid alkylating agent shall be in the said range.

  In the resin composition of the present invention, for example, a compatibilizer, plasticizer, weathering agent, antioxidant, thermal stabilizer, lubricant, antistatic agent, brightener, Various additives such as a colorant, a conductive agent, an ultraviolet absorber, a flame retardant, a flame retardant aid, a pigment, and a dye can be contained.

<Polyester film>
The polyester film of the present invention is formed using the above-described resin composition of the present invention. Since the resin composition of the present invention is used, the polyester film has a planar shape with less adhesion of particulate matter.

  Although the thickness of a polyester film changes with uses, when using as a member of a solar cell backsheet, it is preferable that they are 25 micrometers-300 micrometers, and it is more preferable that they are 120 micrometers-300 micrometers. When the thickness is 25 μm or more, sufficient mechanical strength is obtained, and when the thickness is 300 μm or less, there is an advantage in cost.

The polyester film is preferably stretched, more preferably biaxially stretched, more preferably planar biaxially stretched as compared to stretching such as tubular, and biaxially stretched sequentially. It is particularly preferable.
The biaxially stretched polyester film is stretched in the longitudinal direction (MD: Machine Direction) (hereinafter also referred to as “longitudinal stretching” or “MD stretching”) and in the width direction (TD: Transverse Direction) (hereinafter, “ It is also referred to as “lateral stretching” or “TD stretching”. The longitudinal stretching and the lateral stretching may each be performed once or may be performed a plurality of times. Moreover, you may extend | stretch to MD and TD simultaneously longitudinally and laterally stretching.

The MD orientation degree and the TD orientation degree of the polyester film are each preferably 0.14 or more, more preferably 0.155 or more, and particularly preferably 0.16 or more. When the degree of orientation is 0.14 or more, the restraint property of the amorphous chain is improved (the mobility is lowered), and the hydrolysis resistance is improved.
The MD orientation degree and the TD orientation degree were measured using an Abbe refractometer, a monochromatic light sodium D-line as a light source, methylene iodide as a mounting solution, and an x of the biaxially oriented film in an atmosphere at 25 ° C. The refractive index in the y, z and z directions is measured, the MD orientation degree can be calculated from Δn (x−z), and the TD orientation degree can be calculated from Δn (yz).

The terminal carboxyl group content in the polyester film (the carboxylic acid value of the polyester, hereinafter also referred to as AV) is preferably 25 eq / ton (equivalent / ton; the same shall apply hereinafter) or less, more preferably 20 eq / ton or less. Particularly preferably, it is 16 eq / ton or less, and particularly preferably 15 eq / ton or less. When the terminal carboxyl group content is 25 eq / ton or less, the hydrolysis resistance of the polyester film is more easily maintained, and the deterioration of the resin by the acid alkylating agent of the present invention, in particular, the strength decrease at the time of wet heat aging is effectively suppressed. It is done.
The polyester film preferably has a carboxylic acid value of 200 eq / ton or less, more preferably 100 eq / ton or less, and more preferably 50 eq / ton or less after storage treatment at 120 ° C. and relative humidity of 100% for 105 hours. More preferably.
The carboxylic acid value in the polyester can be adjusted by polymerization catalyst species, polymerization time, and film forming conditions (film forming temperature and time).
The carboxylic acid value is H.264. A. Pohl, Anal. Chem. 26 (1954) 2145, and can be measured by a titration method. Specifically, the carboxylic acid value (eq / ton) is determined appropriately by dissolving polyester in benzyl alcohol at 205 ° C., adding phenol red indicator, and titrating with sodium hydroxide in water / methanol / benzyl alcohol. Is calculated from

The terminal hydroxyl group content in the polyester film is preferably 120 eq / ton or less, more preferably 90 eq / ton or less, based on the polyester. When the hydroxyl group content is 120 eq / ton or less, it reacts preferentially with a carboxyl group, and the carboxylic acid value is further reduced. The lower limit of the hydroxyl group content is preferably 20 eq / ton or more from the viewpoint of adhesion to the adjacent layer. The hydroxyl group content in the polyester can be adjusted by polymerization catalyst species, polymerization time, and film forming conditions (film forming temperature and time).
Terminal hydroxyl group content in the polyester is, using deuterated hexafluoroisopropanol solvent is a value measured by proton nuclear magnetic resonance ^{(1 H-Nuclear Magnetic Resonance,} 1 H-NMR).

The intrinsic viscosity (IV) of the polyester film is preferably 0.55 dl / g to 0.94 dl / g, more preferably 0.60 dl / g to 0.84 dl / g, and 0.70 dl / g to 0. 84 dl / g is more preferable. When the intrinsic viscosity is 0.55 dl / g or more, the film-forming property is improved, and the film thickness is excellent. When the polyester used at the time of film formation is 2 or more kinds (when using the recovered polyester of JP2011-256337 A), the intrinsic viscosity (IV) of the mixed polyester obtained by mixing two or more kinds of polyesters is: It is preferable to satisfy the above range.
Intrinsic viscosity (IV) is calculated | required from the following Formula from the solution viscosity obtained by measuring the solution which melt | dissolved polyester in orthochlorophenol at 25 degreeC.
ηsp / C = [η] + K [η] 2 · C
[Ηsp represents (solution viscosity / solvent viscosity) -1. C represents the mass of the polyester dissolved per 100 ml of the solvent (in this measurement, 1 g / 100 ml), K represents the Huggins constant (0.343), and the solution viscosity and the solvent viscosity are measured using an Ostwald viscometer. It is a value measured using. ]

~ Production method of polyester film ~
-Film formation process-
A resin composition for forming a polyester film, specifically, polyester and imino ether compound, etc. are put into an extruder and melt-kneaded, and the extruded melt is passed through a gear pump and a filter. Extrude to a cooling roll in the form of a film through a die. The extruded melt is brought into close contact with the cooling roll using an electrostatic application method. And an unstretched film can be formed by cooling and solidifying a melt. Under the present circumstances, the surface temperature of a cooling roll can be 10-40 degreeC.

-Stretching process-
The film formed in the film forming step can be subjected to a stretching treatment in the next stretching step to obtain a stretched film. The film cooled and solidified by the cooling roll is preferably stretched in one direction or two directions as desired and stretched in two directions. When extending | stretching to 2 directions, each extending | stretching to each direction (the longitudinal direction of a film, the width direction) may each be performed once, and may be performed in multiple times. Moreover, you may extend | stretch simultaneously to two directions.
The stretching treatment is preferably performed in the range of the glass transition temperature [Tg [° C.]] to (Tg + 60) ° C. of the film, more preferably in the range of (Tg + 3) ° C. to (Tg + 40) ° C., More preferably, it is performed in the range of (Tg + 5) ° C. or higher and (Tg + 30) ° C. or lower.

In the case of stretching, the stretching ratio in at least one direction is preferably 280% to 500%, more preferably 300% to 480%, and further preferably 320% to 460%. When stretching in two directions (biaxial stretching), it may be stretched evenly in two directions, but the stretching ratio in one direction may be larger than the stretching ratio in the other direction, and the stretching may be uneven. More preferred. In this case, you may enlarge any draw ratio of the longitudinal direction (MD) or the width direction (TD) of a film. A draw ratio is calculated | required by the following formula | equation.
Stretch ratio (%) = 100 × (length after stretching) / (length before stretching)

  In biaxial stretching, for example, in the longitudinal direction (MD), the film is stretched once or twice at Tg ° C. or more (Tg + 60) ° C. so that the total stretching ratio is 3 to 6 times, and then the width direction ( TD) may be stretched at Tg ° C. or higher and (Tg + 60) ° C. or lower so that the stretch ratio is 3 to 5 times.

  In biaxial stretching, two or more pairs of nip rolls with increased downstream rotational speed (peripheral speed) are used to stretch in the longitudinal direction (MD) (longitudinal stretching) and then to both ends in the width direction of the film stretched in MD. Is held by a chuck and stretched (laterally stretched) in a direction perpendicular to MD.

  In the stretching step, the film can be heat-treated before or after the stretching process (preferably after the stretching process). By performing heat treatment, microcrystals can be generated, and mechanical properties and durability can be improved. For example, the film may be heat-treated at about 180 ° C. to 210 ° C. (preferably 185 ° C. to 220 ° C.) for 1 second to 60 seconds (preferably 2 seconds to 30 seconds).

In the stretching step, a thermal relaxation treatment can be performed after the heat treatment. The thermal relaxation treatment is a treatment for shrinking the film by applying heat to the film for stress relaxation. The thermal relaxation treatment is preferably performed in both the MD and TD directions of the film. The various conditions in the thermal relaxation treatment are preferably a treatment at a temperature lower than the heat treatment temperature, and preferably 130 to 220 ° C. In the thermal relaxation treatment, the thermal shrinkage of the film at 150 ° C. is preferably 1% to 12% for MD and TD, more preferably 1% to 10%.
The heat shrinkage rate at 150 ° C. can be obtained as follows by cutting out a sample having a length direction of 350 mm and a width direction of 50 mm as the measurement direction. That is, marks are attached at 300 mm intervals in the longitudinal direction near both ends in the width direction of the sample, and one end is fixed to the oven adjusted to a temperature of 150 ° C., and the other end is fixed. Leave it for 30 minutes. After leaving, the distance between the gauge points is measured at room temperature, this distance is taken as L (mm), and the thermal contraction rate is calculated by the following formula.
Thermal shrinkage at 150 ° C. (%) = 100 × (300−L) / 300
When the heat shrinkage rate is positive, it represents shrinkage, and when the heat shrinkage rate is negative, it represents elongation.

~ Use ~
As described above, by using the resin composition of the present invention, a film (for example, a polyester film) excellent in hydrolysis resistance and film surface shape can be produced by the above-described method.
As will be described later, the polyester film of the present invention can be suitably used as a protective sheet for a solar cell module (so-called solar cell backsheet), and can also be used for other applications.
Further, on the polyester film of the present invention, at least one functional group selected from a carboxyl group (COOH), a hydroxyl group (OH), a sulfonic acid group (SO ₃ H), an amino group (NH ₂ ), and a salt thereof is provided. A layer including the coating layer (for example, a coating layer) may be provided and used as a laminated film. The laminated film may be, for example, a laminated film in which a coating layer such as an easy adhesion layer is provided on the polyester film of the present invention.
The polyester film and laminated film of the present invention are used for various applications. As a specific example, a solar cell backsheet (a back surface protection sheet of a solar cell module) is preferably exemplified. The polyester film of the present invention has an excellent film surface shape, and has good adhesion and heat-and-moisture resistance. Therefore, when used for a solar cell backsheet, the power generation efficiency of the solar cell module can be maintained over a long period of time.

  The back sheet for a solar cell can be formed, for example, by providing a desired functional layer on the polyester film of the present invention. As the functional layer, for example, a reflection layer (colored layer) that reflects light reaching the back sheet out of sunlight incident on the solar cell module and returns it to the solar cell, and contributes to adhesion to the sealing material. Examples include an overcoat layer, a back surface layer for protecting the back surface, and a back surface protective layer. Moreover, when providing a functional layer, it is preferable to form an easy-adhesion layer beforehand on a polyester film, and to provide via an easy-adhesion layer. In addition, before providing a functional layer, it is preferable to surface-treat with respect to a polyester film beforehand, and a flame treatment, a corona treatment, a plasma treatment, an ultraviolet treatment etc. can be given as surface treatment, for example.

-Reflective layer (colored layer)-
The solar cell backsheet is preferably provided with a reflective layer that reflects light on the side of the polyester film that contacts the sealing material that seals the solar cells. By providing the reflective layer, the light that has passed through the solar cell and reaches the back sheet among the sunlight incident on the solar cell module can be returned to the solar cell. Thereby, power generation efficiency can be improved. The reflective layer preferably contains a polymer and a colorant (preferably a white pigment).
Preferred examples of the white pigment include titanium oxide, barium sulfate, silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, and talc. Of these, titanium oxide is preferred from the viewpoints of whiteness, reflectance, and durability.
The thickness of the reflective layer is preferably 3 μm to 10 μm, more preferably 4 μm to 8 μm. When the thickness is within the above range, both necessary reflectance and adhesiveness can be achieved.
The reflective layer can be formed using a known coating method such as a roll coat method, a bar coater method, a slide die method, or a gravure coater method.

-Overcoat layer-
The solar cell backsheet may have an overcoat layer on the reflective layer. By having an overcoat layer, adhesiveness with the sealing material which seals a photovoltaic cell can be improved.
The overcoat layer preferably contains a polymer.
The thickness of the overcoat layer is preferably 0.1 μm to 1.0 μm, more preferably 0.2 to 0.8 μm. When the thickness is within the above range, strong adhesiveness with the sealing material for sealing the solar battery cells can be obtained.
The overcoat layer can be formed using a known coating method such as a roll coat method, a bar coater method, a slide die method, or a gravure coater method.

-Back layer-
It is preferable that the solar cell backsheet has the back surface layer which protects a polyester film on the opposite side to the side which contact | connects the sealing material which seals a photovoltaic cell of a polyester film. The back layer preferably contains a polymer, and as an example of the polymer, a silicone-based composite polymer is preferable in terms of durability and adhesion to a polyester film. The silicone-based composite polymer is a polymer including a — (Si (R ¹ ) (R ² ) —O) _n — moiety in the molecule and a polymer structure portion copolymerized with this moiety. By using the silicone-based composite polymer as the polymer, the adhesion between the back layer and the polyester film becomes better, and the adhesion can be kept good for a long period of time.
The back surface layer may contain an ultraviolet absorber, a white pigment, and the like as necessary.
The thickness of the back layer is preferably 3 μm to 12 μm, more preferably 4 μm to 8 μm. When the thickness is within the above range, both durability and adhesiveness can be achieved.
The back layer can be formed using a known coating method such as a roll coating method, a bar coater method, a slide die method, or a gravure coater method.

-Back side protective layer-
The back sheet for solar cell may further include a back surface protective layer on the back surface layer. By having the back surface protective layer, the durability can be further improved.
The back surface protective layer preferably contains a polymer, and from the viewpoint of durability, the polymer is preferably a fluoropolymer. The fluorine-based polymer is a polymer having a structural unit derived from a fluorine-containing monomer in the main chain or side chain. The fluorine-containing monomer may be contained in either the main chain or the side chain, but is preferably contained in the main chain from the viewpoint of durability.
The back surface layer may contain a slip agent, colloidal silica, or the like, if necessary.
The thickness of the back surface protective layer is preferably 0.5 μm to 6 μm, more preferably 1 μm to 5 μm. When the thickness is within the above range, the durability is excellent.
The back surface protective layer can be formed using a known coating method such as a roll coating method, a bar coater method, a slide die method, or a gravure coater method.

~ Solar cell module ~
A solar cell module can be produced using the polyester film of the present invention or the above solar cell backsheet. The solar cell module includes a solar cell (solar cell element) that converts light energy of sunlight into electric energy, a transparent substrate on which sunlight is incident, and the polyester film of the present invention described above (back sheet for solar cell). ). Between the substrate and the polyester film, for example, the solar battery cells can be sealed with a resin (so-called sealing material) such as an ethylene-vinyl acetate copolymer.

  The members other than the solar cell module, the solar cell, and the back sheet are described in detail in, for example, “Photovoltaic power generation system constituent material” (supervised by Eiichi Sugimoto, Kogyo Kenkyukai, published in 2008).

  The transparent substrate only needs to have a light-transmitting property through which sunlight can pass, and can be appropriately selected from base materials that transmit light. From the viewpoint of power generation efficiency, the higher the light transmittance, the better. For such a substrate, for example, a glass substrate, a transparent resin such as an acrylic resin, or the like can be suitably used.

  Solar cells include silicon-based materials such as single crystal silicon, polycrystalline silicon, and amorphous silicon, III-V groups such as copper-indium-gallium-selenium, copper-indium-selenium, cadmium-tellurium, gallium-arsenide, and II Various known solar cell elements such as a group VI compound semiconductor can be applied.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “part” is based on mass.

(Synthesis of imino ether compounds)
[Synthesis Example 1]: Synthesis of Exemplary Compound (1)

  To a solution of 5.0 g (20.7 mmol) of 2-phenyl-4-chloroquinazoline in 50 ml of tetrahydrofuran, 4.8 g of a sodium methoxide methanol solution (28% by mass) was slowly added dropwise at room temperature. After stirring at room temperature for 2 hours, ethyl acetate / water was added for liquid separation. The organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained solid was added to an ethyl acetate hexane mixed solvent and boiled, and a trace amount of solid was removed by filtration. The filtrate was distilled off under reduced pressure to obtain 4.5 g (yield 92%) of Exemplary Compound (1).

[Synthesis Example 2]: Synthesis of Exemplified Compound (3)

  To 500 ml of a tetrahydrofuran solution of 31 g (0.5 mol) of ethylene glycol, 20 g (0.5 mol) of sodium hydride (60% by mass) was added in portions at 5 ° C. After generation of gas stopped, the temperature was raised to room temperature and stirred for 30 minutes. Thereafter, the mixture was cooled to 5 ° C., and 50 g (207 mmol) of 2-phenyl-4-chloroquinazoline was added in portions. After stirring at room temperature for 2 hours, ethyl acetate / water was added for liquid separation. The organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained solid was added to an ethyl acetate hexane mixed solvent and boiled, and a trace amount of solid was removed by filtration. Purification by silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent) gave 34.7 g (yield 63%) of Exemplary Compound (3).

[Synthesis Example 3]: Synthesis of Exemplary Compound (6)

  To 100 ml of a pyridine solution of 31 g (500 mmol) of ethylene glycol, 50 ml of a toluene solution of 14.8 g (50 mmol) of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid chloride (6-1) was adjusted to the temperature of the reaction solution. The solution was added dropwise while maintaining at 15 ° C. After completion of dropping, the temperature was raised to room temperature and stirred for 2 hours. Ethyl acetate and water were added for liquid separation, and the organic layer was washed with 2N aqueous hydrochloric acid. The obtained organic layer was washed with water and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. Purification by silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent) gave 17.1 g (yield 65%) of compound (6-2).

  1.7 g (42 mmol) of sodium hydride (60 mass%) was added in portions to 100 ml of a tetrahydrofuran solution of 10 g (19 mmol) of the compound (6-2) at 5 ° C. After generation of gas stopped, the temperature was raised to room temperature and stirred for 30 minutes. Thereafter, the mixture was cooled to 5 ° C., and 5.0 g (20.7 mmol) of 2-phenyl-4-chloroquinazoline was added in portions. After stirring at room temperature for 2 hours, ethyl acetate / water was added for liquid separation. The organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. By purifying with silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent), 9.0 g (yield 82%) of the exemplified compound (6) was obtained.

[Synthesis Example 4]: Synthesis of Exemplified Compound (11)

  To 100 ml of an ethyl acetate solution of 4.9 g (16.6 mmol) of triphosgene, 100 ml of a tetrahydrofuran solution of 13.3 g (50 mmol) of Exemplified Compound (3) and 7.5 g (50 mmol) of N, N-diethylaniline was added dropwise at 15 ° C. did. After dripping, the temperature was raised to room temperature, and the mixture was further stirred for 1 hour. Water was added for liquid separation, and the organic layer was washed with water three times. After drying the organic layer with magnesium sulfate, the solvent was distilled off under reduced pressure. To the mixture, 30 ml of tetrahydrofuran was added dropwise to 8.5 g (50 mmol) of 4-hydroxy-1,2,2,6,6-pentamethylpiperidine and 50 ml of N, N-dimethylformamide containing 10 ml of pyridine. After completion of the dropwise addition, a catalytic amount of N, N-dimethylaminopyridine was added and stirred overnight at room temperature. Ethyl acetate / water was added for liquid separation. The organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. By purification with silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent), 10.9 g (43% yield) of Exemplified Compound (11) was obtained.

[Synthesis Example 5]: Synthesis of Exemplified Compound (19)

  To a 500 ml tetrahydrofuran solution of 1.36 g (10 mmol) of pentaerythritol, 2.00 g (50 mmol) of sodium hydride (60 mass%) was added in portions. After generation of gas stopped, the temperature was raised to room temperature and stirred for 30 minutes. Thereafter, the mixture was cooled to 5 ° C., and 12.0 g (50 mmol) of 2-phenyl-4-chloroquinazoline was added in portions. After stirring for 2 hours at room temperature, the mixture was stirred overnight at 50 ° C. Ethyl acetate / water was added for liquid separation, and the organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. Purification by silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent) gave 6.8 g (yield 71%) of the exemplified compound (19).

[Synthesis Example 6]: Synthesis of Exemplified Compound (13)

  To a tetrahydrofuran solution of 13.0 g (0.1 mol) of 2-ethylhexanol, 4.0 g (0.1 mol) of sodium hydride (60% by mass) was added in portions. After generation of gas stopped, the temperature was raised to room temperature and stirred for 30 minutes. Thereafter, the mixture was cooled to 5 ° C., and 5.5 g (30 mmol) of cyanuric chloride was added in portions. After stirring at room temperature for 5 hours, ethyl acetate / water was added for liquid separation. The organic layer was washed with water and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. By purification with silica gel chromatography (eluent: ethyl acetate / hexane mixed solvent), 11.6 g (yield 83%) of Exemplary Compound (13) was obtained.

Example 1
<1. Preparation of saturated polyester resin>
-Process (A)-
4.7 tons of high-purity terephthalic acid and 1.8 tons of ethylene glycol were mixed for 90 minutes to form a slurry, which was continuously supplied to the first esterification reactor at a flow rate of 3800 kg / h. Next, an ethylene glycol solution of a citric acid chelate titanium complex (“VERTEC AC-420”, manufactured by Johnson Matthey) in which citric acid is coordinated to titanium (Ti) metal was continuously supplied to the first esterification reaction tank. The reaction was carried out with an average residence time of about 4.4 hours while stirring at an internal temperature of 250 ° C. to obtain an oligomer. At this time, the citric acid chelate titanium complex was continuously added so that the amount of Ti added was 9 ppm in terms of element. The oligomer obtained had a carboxylic acid value of 500 eq / ton.

The obtained oligomer was transferred to the second esterification reaction tank and reacted under the conditions of a reaction tank temperature of 250 ° C. and an average residence time of 1.2 hours to obtain an oligomer having a carboxylic acid value of 180 eq / ton. . The inside of the second esterification reaction tank is partitioned into three zones, the first zone to the third zone. In the second zone, the ethylene glycol solution of magnesium acetate is added in terms of elemental conversion value of magnesium (Mg). In the third zone, an ethylene glycol solution of trimethyl phosphate was continuously supplied so that the addition amount of phosphorus (P) was 65 ppm in terms of element.
The ethylene glycol solution of trimethyl phosphate was prepared by adding a 25 ° C. trimethyl phosphate solution to a 25 ° C. ethylene glycol solution and stirring at 25 ° C. for 2 hours (phosphorus compound content in the solution: 3 .8% by mass).
As described above, an esterification reaction product was obtained.

-Process (B)-
Next, the esterification reaction product obtained in the step (A) is continuously supplied to the first polycondensation reaction tank, and the reaction temperature is 270 ° C. and the reaction tank pressure is 20 torr (2.67 × 10 ⁻³ MPa). While the esterification reaction product was stirred under the conditions, polycondensation (transesterification reaction) was performed under the condition of an average residence time of about 1.8 hours.

The obtained reaction product was transferred from the first polycondensation reaction tank to the second double condensation reaction tank. Thereafter, in the second double condensation reaction tank, the reaction product was stirred under conditions of a reaction tank temperature of 276 ° C. and a reaction tank pressure of 5 torr (6.67 × 10 ⁻⁴ MPa), and a residence time of about 1.2 hours. (Transesterification reaction).

Subsequently, the reaction product obtained by the transesterification reaction was transferred from the second double condensation reaction tank to the third triple condensation reaction tank. In the third triple condensation reaction tank, the reaction was carried out under the conditions of a residence time of 1.5 hours while stirring under the conditions of a reaction tank temperature of 276 ° C. and a reaction tank pressure of 1.5 torr (2.0 × 10 ⁻⁴ MPa). Transesterification reaction) was performed to obtain polyethylene terephthalate (PET) as a reaction product. The obtained PET had a carboxylic acid value (Acid Value, AV) of 22 eq / ton and an IV (inherent viscosity) of 0.65 dl / g.

AV is calculated from an appropriate amount obtained by dissolving polyester in benzyl alcohol at 205 ° C., adding a phenol red indicator, and titrating with a water / methanol / benzyl alcohol solution of sodium hydroxide.
IV is obtained from the following equation from the solution viscosity obtained by measuring a solution of polyester in orthochlorophenol at 25 ° C.
ηsp / C = [η] + K [η] 2 · C
In the formula, ηsp represents (solution viscosity / solvent viscosity) -1. C represents the mass of the polyester dissolved per 100 ml of the solvent (in this measurement, 1 g / 100 ml), K represents the Huggins constant (0.343), and the solution viscosity and the solvent viscosity are measured using an Ostwald viscometer. It is a value measured using.

<2. Preparation of polyester film>
-Extrusion molding-
The PET obtained above is introduced into the hopper of a twin-screw kneader / extruder in which a screw having a diameter of 50 mm is disposed in the cylinder by a main feeder, and an iminoether compound (an acid alkyl represented by the general formula (1)) is added. 5 parts of Exemplified Compound (6)) and 0.1 part of 4-tert-butylbenzoic acid (a-1) are charged in a sub-feeder and melt-kneaded for 2 minutes at 280 ° C. The composition was extruded to obtain a resin composition. In this resin composition, the content ratio (Exemplary Compound (6) / PET; mass basis) of Exemplified Compound (1) to PET was 0.05 (5% by mass).
After passing the extruded melt (melt) through a gear pump and a filter (pore size 20 μm), it is extruded from a die to a cooling roll at 20 ° C., and solidified by adhering to the cooling roll using an electrostatic application method. A characteristic film was obtained.

<Evaluation>
The following evaluation was performed. The evaluation results are shown in Table 1 below.
-1. Moisture and heat resistance (PCT test)-
The hydrolysis resistance was evaluated based on the half life of elongation at break. The breaking elongation retention half-life is that the obtained polyester film is subjected to a storage treatment (heat treatment) under conditions of 120 ° C. and a relative humidity of 100%, and the elongation at break (%) exhibited by the polyester film after storage. However, it evaluated by measuring the storage time which becomes 50% with respect to the breaking elongation (%) which the polyester film before storage shows. The obtained results are shown in Table 1 below.
Here, a polyester film was prepared in the same manner as in Example 1 except that the acid alkylating agent and the organic acid were not added in Example 1, and used as a reference film.
<Evaluation criteria>
A: The above-mentioned storage time is long with respect to the reference film.
B: The above-mentioned storage time is the same as that of the reference film.
C: The above-mentioned storage time is short with respect to the reference film.

-2. Gas volatilization during production
Sensory evaluation was performed on smoke and odor generated from the die of the twin-screw kneading extruder, and volatility was evaluated according to the following criteria.
<Evaluation criteria>
A: Smoke and odor were not generated.
B: Smoke was not generated, but generation of odor was observed.
C: Generation of smoke and odor was observed.

-3. Film surface-
The obtained polyester film was visually observed, and the surface condition of the film was evaluated according to the following criteria. In addition, the absence of gel-like irregularity indicates that gelation in the resin composition used for producing the film is suppressed.
Here, the gel-like irregularity refers to a convex abnormal part visually recognized as a bright spot on a smooth and uniform film surface.
<Evaluation criteria>
A: There were no gel-like spots on the film surface.
B: Gel-like irregularities were found on the film surface.

(Examples 2-18, Comparative Examples 1-13)
In Example 1, <2. Preparation of polyester film> The same procedure as in Example 1 except that the acid alkylating agent, the amount of acid alkylating agent added, and the type of organic acid used in the extrusion were changed as shown in Table 1 below. A polyester film was prepared and evaluated. The evaluation results are shown in Table 1 below.
In addition, the exemplified compound (9) of the acid alkylating agent in Table 1 can also be synthesized by a method similar to the acid alkylating agent such as the exemplified compound (6).

  As shown in Table 1, in the examples using the acid alkylating agent represented by the general formula (1), the moisture and heat resistance is improved as compared with the comparative examples using other acid alkylating agents. This indicates that the acidic component, which is a factor that deteriorates the wet heat of the polyester film, is efficiently inactivated by reaction. Moreover, since generation | occurrence | production of irritating gas was prevented and generation | occurrence | production of the gel-like spot on the film surface was suppressed, it turns out that the production | generation of the gel component in resin was also suppressed. Thereby, provision of the polyester film excellent in surface shape was possible.

  The present invention includes a compound having an acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group, and is suitable for a field where excellent durability performance is required. For example, it is suitably used as an acid sealant for a resin film (eg, polyester film) used for a solar cell backsheet, which requires hydrolysis resistance over a long period of time.

Claims (10)

An acid alkylating agent represented by the following general formula (1), which acid-alkylates a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group.


In the general formula (1), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring.   The acid alkylating agent according to claim 1, wherein Q represents a group which forms a nitrogen-containing 6-membered ring by binding to a -C = N- site. Q represents a group that forms a condensed ring of a triazine ring or a nitrogen-containing 6-membered ring and a benzene ring by bonding to the —C═N— moiety, R ¹¹ represents a hydrogen atom, R ¹² and R ¹² The acid alkylating agent according to claim 1 or 2, wherein each ¹³ independently represents a hydrogen atom or an alkyl group.   4. The nitrogen-containing heterocycle containing Q and a —C═N— moiety is a quinazoline ring which is a 10-membered ring in which a benzene ring and a pyrimidine ring are condensed. 5. Acid alkylating agent. An acid alkylating agent represented by the following general formula (2), which acid-alkylates a compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group.


In General Formula (2), Q represents a group that forms a 5- to 12-membered nitrogen-containing heterocycle by binding to the —C═N— moiety. R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. L ¹ represents a p-valent group whose bond terminal to Q is an alkylene moiety, an arylene moiety, or an alkyleneoxy moiety. p represents an integer of 2 to 4. R ¹¹ , R ¹² and R ¹³ may combine with each other to form a ring. The acid alkylating agent according to any one of claims 1 to 5,
A compound having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group;
The method of producing | generating the acid alkylation thing which produces | generates an acid alkylation thing by making it react in the temperature range of 100 to 350 degreeC.   The acid alkylating agent according to any one of claims 1 to 5, a resin having at least one acidic group selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group, A resin composition comprising:   The resin composition according to claim 7, wherein the resin is polyester.   The resin composition according to claim 8, obtained by mixing the acid alkylating agent and the polyester in a molten state.   The polyester film shape | molded using the resin composition of Claim 8 or Claim 9.