CN113728040A

CN113728040A - Polyester resin composition

Info

Publication number: CN113728040A
Application number: CN202080027894.7A
Authority: CN
Inventors: 佐佐木雄大; 谷口彰; 小谷沙织
Original assignee: Nisshinbo Chemical Inc
Current assignee: Nisshinbo Chemical Inc
Priority date: 2019-04-15
Filing date: 2020-03-16
Publication date: 2021-11-30
Anticipated expiration: 2040-03-16
Also published as: WO2020213326A1; CN113728040B; JP2020176168A; JP7312005B2

Abstract

The invention provides a polyester resin composition which can obtain polyester resin with excellent hydrolysis resistance and inhibit generation of isocyanate gas due to heating in melt kneading or molding processing. The polyester resin composition comprises a polyester resin (A), a predetermined carbodiimide compound (B), and an organic compound (C) having at least one of an epoxy group and a hydroxyl group, wherein the content of the carbodiimide compound (B) is 0.1 to 10.0 parts by mass, and the mass ratio of the organic compound (C) to the carbodiimide compound (B) is 0.1 to 10.0 parts by mass, based on 100 parts by mass of the total of the polyester resin (A), the carbodiimide compound (B), and the organic compound (C).

Description

Polyester resin composition

Technical Field

The present invention relates to a polyester resin composition having excellent hydrolysis resistance.

Background

Polyester resins are generally used in fibers, films, sheets and the like because of their excellent transparency, mechanical strength, processability, solvent resistance, recyclability and the like, and are also used in housings of home electric appliances and OA devices.

However, since polyester resins are easily degraded by hydrolysis with the passage of time, carbodiimide compounds may be added to suppress the degradation and improve hydrolysis resistance.

It is also known that when a carbodiimide compound is added, hydrolysis resistance can be further improved by using an epoxy compound in combination.

For example, patent document 1 describes that an epoxy compound and a carbodiimide compound are added to an aromatic polyester to improve hydrolysis resistance.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. Hei 1-174557

Disclosure of Invention

Patent document 1 specifically discloses a monocarbodiimide compound in which hydrocarbon groups are bonded to both ends of a carbodiimide group, or a polycarbodiimide compound having hydrocarbon groups directly bonded to carbodiimide groups at both ends. Such a carbodiimide compound is not preferable in terms of the working environment in the production of the polyester-based resin because the carbodiimide compound is easily decomposed to generate isocyanate gas by melting and kneading of the polyester-based resin composition or heating in the molding process.

Further, the aliphatic carbodiimide is likely to generate isocyanate gas as described above, and even when used in combination with an epoxy compound, the effect of improving the hydrolysis resistance of the polyester-based resin cannot be sufficiently obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a polyester resin composition which can obtain a polyester resin having excellent hydrolysis resistance and in which generation of isocyanate gas due to heating during melt kneading or molding is suppressed.

The present invention has been accomplished based on the finding that a polyester-based resin composition which can impart a higher hydrolysis resistance to a polyester-based resin than conventional polyester-based resins and can suppress generation of isocyanate gas by heating during melt kneading or molding can be obtained by using a predetermined carbodiimide compound and a compound having an epoxy group and/or a hydroxyl group in combination.

Namely, the present invention provides the following [1] to [7 ].

[1] A polyester resin composition comprising a polyester resin (A), a carbodiimide compound (B) represented by the following formula (1), and an organic compound (C) having at least one of an epoxy group and a hydroxyl group, wherein the content of the carbodiimide compound (B) is 0.1 to 10.0 parts by mass, and the mass ratio of the organic compound (C) to the carbodiimide compound (B) is 0.1 to 10.0 parts by mass, based on 100 parts by mass of the total of the polyester resin (A), the carbodiimide compound (B), and the organic compound (C).

[ chemical formula 1]

(in the formula, R¹And R²Each independently is a residue obtained by removing 1 functional group reactive with an isocyanate group from an organic compound (Y) having the functional group.

R³A 2-valent residue obtained by removing 2 isocyanate groups from a diisocyanate compound. The diisocyanate compound has a structure directly contacting the isocyanate groupA bonded benzene-based aromatic ring, and the benzene-based aromatic ring does not have a substituent at both ortho-positions of the isocyanate group. Plural R³The same or different from each other.

R⁴A 2-valent residue obtained by removing 2 hydroxyl groups from a diol compound. R⁴When there are plural, each R⁴The same or different from each other.

The organic compound (Y) is at least one selected from the group consisting of monoalcohols, monoamines, monocarboxylic acids, and acid anhydrides.

X¹And X²Each independently is a bond formed by a reaction of the functional group of the organic compound (Y) with the isocyanate group of the diisocyanate compound.

m is a number of 0 to 50, and n is a number of 1 to 50. )

[2] The polyester resin composition according to the above [1], wherein the organic compound (C) is at least one selected from the group consisting of an epoxy compound having an epoxy equivalent of 170 to 750 and a hydroxyl compound having a hydroxyl equivalent of 170 to 750.

[3] The polyester resin composition according to the above [1] or [2], wherein the organic compound (C) is a solid at 25 ℃ under 1 atm.

[4] The polyester-based resin composition according to any one of the above [1] to [3], wherein the diisocyanate compound is at least one selected from the group consisting of p-phenylene diisocyanate, toluene diisocyanate, tolidine diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate.

[5] The polyester resin composition according to any one of the above [1] to [4], wherein the organic compound (Y) is a monohydric alcohol.

[6] The polyester resin composition according to any one of the above [1] to [5], wherein the diol compound is at least one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols and polyurethane polyols.

[7] The polyester resin composition according to any one of the above [1] to [6], wherein the polyester resin (A) is at least one selected from the group consisting of polyethylene terephthalate, polybutylene succinate, polylactic acid and polyhydroxyalkanoic acid.

According to the present invention, there is provided a polyester resin composition in which generation of isocyanate gas due to heating during melt kneading or molding is suppressed, and a polyester resin having more excellent hydrolysis resistance than the conventional polyester resin can be obtained.

Detailed Description

The polyester resin composition of the present invention comprises a polyester resin (A), a carbodiimide compound (B) represented by the following formula (1), and an organic compound (C) having at least one of an epoxy group and a hydroxyl group. The content of the carbodiimide compound (B) is 0.1 to 10 parts by mass and the mass ratio of the organic compound (C) to the carbodiimide compound (B) is 0.1 to 10.0, based on 100 parts by mass of the total of the polyester resin (A), the carbodiimide compound (B) and the organic compound (C).

[ chemical formula 2]

In the formula (1), R¹And R²Each independently is a residue obtained by removing 1 functional group reactive with an isocyanate group from an organic compound (Y) having the functional group.

R³A 2-valent residue obtained by removing 2 isocyanate groups from a diisocyanate compound. The diisocyanate compound has a benzene-based aromatic ring directly bonded to the isocyanate group, and has no substituent at both ortho-positions of the isocyanate group of the benzene-based aromatic ring. Plural R³The same or different from each other.

m is a number of 0 to 50, and n is a number of 1 to 50.

The polyester resin composition described above can produce a polyester resin having less isocyanate gas generated by heating during melt kneading or molding and having more excellent hydrolysis resistance than the conventional polyester resin.

[ polyester resin (A) ]

The polyester-based resin (a) in the polyester-based resin composition of the present invention is not particularly limited as long as it is a resin having an ester group. The polyester resin (A) may be used alone or in combination of two or more.

The polyester-based resin (a) is obtained as a resin having an ester bond in the main chain, for example, by a polycondensation reaction between a dibasic acid or an acid anhydride thereof or a dibasic acid ester and a dihydric alcohol, or a polycondensation reaction or a ring-opening polymerization of a hydroxycarboxylic acid or a cyclic derivative thereof.

Examples of the dibasic acid or anhydride thereof include: phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, chlorendic anhydride, endomethylenetetrahydrophthalic anhydride, maleic anhydride, fumaric acid, itaconic acid, and the like.

Examples of the dibasic acid ester include dimethyl terephthalate and dimethyl naphthalenedicarboxylate.

Examples of the diol include: ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A, bisphenol A-2-hydroxypropyl ether, cyclohexanedimethanol, and the like. In addition, there can be mentioned: polyether glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

Examples of the hydroxycarboxylic acid or the cyclic derivative thereof include: lactic acid, hydroxybutyric acid, lactide, beta-propiolactone or delta-valerolactone, and the like.

Specific examples of the polyester-based resin (a) include: polyethylene terephthalate (hereinafter, abbreviated as "PET"), polybutylene terephthalate (hereinafter, abbreviated as "PBT"), polybutylene succinate adipate, polybutylene adipate-terephthalate, polyethylene naphthalate, polyarylate, an ethylene terephthalate-isophthalate copolymer, and a polyalkanoic acid such as polylactic acid and polyhydroxybutyric acid. Among them, from the viewpoints of processability, cost, and the like, PET, PBT, polybutylene succinate, polylactic acid, and polyhydroxyalkanoic acid are preferably used, more preferably PET and PBT, and particularly preferably PBT.

The content of the polyester resin (A) in the polyester resin composition is preferably 80.0 to 99.8 parts by mass, more preferably 85.0 to 99.5 parts by mass, and still more preferably 90.0 to 99.0 parts by mass, based on 100 parts by mass of the total of the polyester resin (A), the carbodiimide compound (B), and the organic compound (C).

[ carbodiimide Compound (B) ]

The carbodiimide compound (B) in the polyester resin composition of the present invention is a compound represented by the following formula (1).

By adding and mixing such a carbodiimide compound to the polyester-based resin (a), generation of isocyanate gas due to heating during melt kneading or molding of the polyester-based resin composition can be suppressed. Further, by adding and mixing the carbodiimide compound (B) and the organic compound (C) to the polyester-based resin (a), the polyester-based resin (a) can be provided with more excellent hydrolysis resistance than ever before.

[ chemical formula 3]

＜R¹And R²＞

Said formula(1) R in (1)¹And R²Is a residue obtained by removing 1 functional group reactive with an isocyanate group from an organic compound (Y) having the functional group. The organic compound (Y) is a blocking agent for blocking a terminal isocyanate group in the compound represented by the formula (1). The R is¹And said R²May be the same as or different from each other.

The organic compound (Y) is at least one selected from the group consisting of monoalcohols, monoamines, monocarboxylic acids, and acid anhydrides. The organic compound (Y) may be one of these compounds alone, or two or more of them may be used.

In the case of a monohydric alcohol, the functional group is a hydroxyl group, and a urethane bond is formed by the reaction of the functional group with an isocyanate group. In the case of monoamines, the functional group is an amino group, and a urea bond is formed by the reaction of this functional group with an isocyanate group. In the case of monocarboxylic acids, the functional group is a carboxyl group, and an amide bond is formed by the reaction of the functional group with an isocyanate group. In the case of an acid anhydride, the functional group is an acid anhydride, and an imide bond is formed by a reaction of the functional group with an isocyanate group. The bond formed by the reaction of each of these functional groups with an isocyanate group corresponds to X in the above formula (1)¹And X²。

Examples of the monohydric alcohol include: aliphatic alcohols such as methanol, ethanol, isopropanol, octanol, and dodecanol; alicyclic alcohols such as cyclohexanol; and (poly) ether monools such as (poly) ethylene glycol monomethyl ether and (poly) propylene glycol monomethyl ether.

Examples of the monoamine include: primary amines such as butylamine and cyclohexylamine; secondary amines such as diethylamine, dibutylamine, dicyclohexylamine and the like.

Examples of the monocarboxylic acid include: formic acid, acetic acid, propionic acid, isovaleric acid, caproic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, and the like.

Examples of the acid anhydride include: phthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, benzoic anhydride, and the like.

Among the organic compounds (Y), monohydric alcohols are preferred from the viewpoints of high reactivity with isocyanate groups, ease of handling as the blocking agent in the synthesis of the carbodiimide compound (B), and effective suppression of generation of isocyanate gas by decomposition of the carbodiimide compound (B). Among them, isopropyl alcohol, octanol, and cyclohexanol are preferable from the viewpoint of easy handling. In addition, from the viewpoint of suppressing volatilization of organic substances, dodecanol is preferable.

＜X¹And X²＞

X in the formula (1)¹And X²Each independently represents the functional group represented by the organic compound (Y) and R³A bond formed by reaction of an isocyanate group of a diisocyanate compound of the source compound (1). As described above, the X¹And X²Are bonds corresponding to the organic compound (Y) and may be the same as or different from each other.

＜R³＞

R in the formula (1)³A 2-valent residue obtained by removing 2 isocyanate groups from a diisocyanate compound. The diisocyanate compound is an aromatic diisocyanate having a benzene-based aromatic ring directly bonded to the isocyanate group. The diisocyanate compound has one or more than two benzene aromatic rings, and the two isocyanate groups are respectively and directly bonded with the same or different benzene aromatic rings. The benzene-based aromatic ring to which each isocyanate group is bonded does not have a substituent at both ortho-positions relative to the bonding position of the isocyanate group. That is, the benzene-based aromatic ring to which each isocyanate group is bonded has a substituent at only one ortho position relative to the bonding position of the isocyanate group, or has no substituent at both ortho positions.

A plurality of R in the formula (1)³May be the same as or different from each other.

It is considered that R³The compound (B) is derived from an aromatic diisocyanate as described above, and the carbodiimide compound (B) has high reactivity with a carboxyl group because a carbodiimide group is directly bonded to a benzene-based aromatic ring, and is therefore highly reactive with a conventional aliphatic carbonThe carbodiimide can impart good hydrolysis resistance to the polyester resin even when the carbodiimide equivalent is large as compared with the polyester resin.

As an aromatic carbodiimide compound which has been frequently used conventionally, Stabaxol (registered trademark) P100 (manufactured by rhine chemical corporation), which is a polymer of 2,4, 6-triisopropylbenzene-1, 3-diyl diisocyanate (poly (1,3, 5-triisopropylphenylene-2, 4-carbodiimide)), is known, for example. The compound has isopropyl groups at both ortho positions relative to a carbodiimide group of a benzene aromatic ring directly bonded to the carbodiimide group. The free isocyanate group generated by decomposing the compound by heating when added to a polyester-based resin for melt kneading or molding is affected by steric hindrance of the isopropyl group and the like, and therefore, the isocyanate group is liable to volatilize as an isocyanate gas because of its low reactivity.

In contrast, the carbodiimide compound (B) of the present invention has the following structure: the benzene-based aromatic ring directly bonded to the carbodiimide group has no substituent at both ortho-positions relative to the carbodiimide group, or has a substituent at only one of the ortho-positions. Therefore, even when the carbodiimide compound (B) is decomposed by heating during melt kneading or molding to generate free isocyanate groups, the polyester-based resin composition of the present invention is highly reactive and therefore easily reacts with the organic compound (C) in the polyester-based resin composition, and can suppress generation of isocyanate gas.

As R³Examples of the diisocyanate compound of the source compound of (3) include: p-phenylene diisocyanate, toluene diisocyanate (hereinafter abbreviated as "TDI"), tolidine diisocyanate, diphenylmethane diisocyanate (hereinafter abbreviated as "MDI"), naphthalene diisocyanate, and the like. One of the diisocyanate compounds may be used alone, or two or more of them may be used in combination. Among them, MDI is preferable from the viewpoint of suppressing generation of isocyanate gas by heating in melt kneading or molding of the polyester-based resin composition.

Two isomers of 2,4-TDI and 2,6-TDI exist in TDI. The kind of these isomers is not particularly limited, and from the viewpoint of availability and the like, a mixture of 2,4-TDI and 2,6-TDI is usually used, and it is preferable to use a mixture containing 75 to 85 mol% of 2,4-TDI in 100 mol% of the mixture.

Three isomers of 2,2 ' -MDI, 2,4 ' -MDI and 4,4 ' -MDI exist in MDI. The kind of these isomers is not particularly limited, and from the viewpoint of availability and the like, a mixture of 2,4 ' -MDI and 4,4 ' -MDI, or a monomer of 4,4 ' -MDI is generally preferable. From the viewpoint of suppressing an increase in melt viscosity of the carbodiimide compound (B), a mixture of 2,4 '-MDI and 4, 4' -MDI is more preferable.

In the mixture of 2,4 ' -MDI and 4,4 ' -MDI, the molar content of 2,4 ' -MDI in 100 mol% of the mixture is preferably 30 to 70 mol%, more preferably 40 to 65 mol%, and still more preferably 50 to 60 mol%.

＜R⁴＞

R in the formula (1)⁴A 2-valent residue obtained by removing 2 hydroxyl groups from a diol compound. A plurality of R in the formula (1)⁴May be the same as or different from each other.

The diol compound is a compound having two hydroxyl groups, and urethane bonds are formed by reaction with the isocyanate groups of the diisocyanate compound in the two hydroxyl groups, respectively. Thus, the carbodiimide compound (B) has a structure in which a urethane bond is introduced into a carbodiimide segment.

By introducing such a urethane bond, the carbodiimide compound (B) has improved compatibility with the polyester-based resin (a) as compared with the case where no urethane bond is introduced, and it is estimated that the polyester-based resin (a) is less likely to undergo a partial crosslinking reaction during heating in melt kneading or molding of the polyester-based resin composition, and an increase in melt viscosity is suppressed.

The diol compound may be a low molecular compound or a high molecular compound. However, in order to impart good hydrolysis resistance to the polyester resin (a) by the carbodiimide compound (B), it is preferable that the carbodiimide equivalent of the carbodiimide compound (B) is not excessively large, and from the viewpoint of appropriate solution viscosity and melt viscosity of the polyester resin composition, the molecular weight of the diol compound is preferably 100 to 40000, more preferably 150 to 10000, and still more preferably 200 to 2000.

The molecular weight of the diol compound in the case of a polymer compound can be measured as a number average molecular weight Mn (in terms of polystyrene as a standard substance) by gel permeation chromatography.

Examples of the diol compound include: aliphatic diols such as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, 1, 2-butanediol, 2-methyl-1, 3-propanediol, neopentyl glycol, 1, 5-pentanediol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, and 1, 4-dihydroxy-2-butene; alicyclic diols such as cyclohexanediol, cyclohexanedimethanol and hydrogenated bisphenol a; aromatic diols such as bishydroxyethoxybenzene, xylene glycol and bis (2-hydroxyethyl) terephthalic acid. In addition, there can be mentioned: polyether polyols such as polyalkylene glycols, polyester polyols, polycarbonate polyols, polyurethane polyols, and glycol-modified silicones. Among these, from the viewpoints of compatibility with the polyester resin (a), imparting good hydrolysis resistance to the polyester resin (a), and the like, polyether polyols, polyester polyols, polycarbonate polyols, and polyurethane polyols are preferable, and polyester polyols are more preferable.

＜m＞

M in the formula (1) is a number of 0 to 50, preferably a number of more than 0 and 20 or less, and more preferably a number of 1 to 10.

When M is 0, the carbodiimide compound (B) does not contain the unit (M) [ NH-CO-O-R⁴-O-CO-NH-R³]Said unit (M) containing R as a source compound from said diol compound⁴And R³With urethane linkages therebetween. The carbodiimide compound (B) can impart good hydrolysis resistance to the polyester-based resin (a) by using it in combination with the organic compound (C) even when the unit (M) is not contained.

When M is more than 0, the carbodiimide compound (B) improves the compatibility with the polyester-based resin (A) by the unit (M).

When m is more than 50, the solution viscosity and melt viscosity of the polyester resin composition become too high, which is not preferable.

＜n＞

N in the formula (1) is a number of 1 to 50, preferably a number of 2 to 40, and more preferably a number of 3 to 30.

Said n is a group containing a group represented by the formula R³A carbodiimide group unit (N) [ N ═ C ═ N-R ] formed by polymerization (decarboxylation condensation reaction) of a diisocyanate compound derived from the compound (a)³]The number of (b) represents the number of carbodiimide groups, and is also referred to as the average degree of polymerization of carbodiimide groups.

When the n is less than 1, the effect of imparting hydrolysis resistance to the polyester resin (A) by the carbodiimide compound (B) cannot be obtained.

When n is more than 50, it is difficult for the carbodiimide compound (B) to obtain good compatibility with the polyester-based resin (A), and the solution viscosity and melt viscosity of the polyester-based resin composition become too high due to the increase in molecular weight, which is not preferable.

When the unit (M) and the unit (N) in the formula (1) are each a plurality of units, the copolymer of each unit may be a block copolymer or a random copolymer. That is, the m and the n are not limited to the number of units of only the block portion in the block copolymer.

The carbodiimide compound (B) preferably has a carbodiimide equivalent (formula weight per 1 mole of carbodiimide group) of 200 to 1500, more preferably 220 to 1000, and even more preferably 250 to 700, from the viewpoints of imparting good hydrolysis resistance to the polyester resin (a) and suppressing generation of isocyanate gas by heating in melt kneading and molding of the polyester resin composition.

The content of the carbodiimide compound (B) in the polyester resin composition is 0.1 to 10.0 parts by mass, preferably 0.2 to 7.0 parts by mass, and more preferably 0.3 to 5.0 parts by mass, relative to 100 parts by mass of the total amount of the polyester resin (A), the carbodiimide compound (B), and the organic compound (C).

When the content is less than 0.1 part by mass, sufficient hydrolysis resistance cannot be imparted to the polyester resin (a). On the other hand, when the content exceeds 10.0 parts by mass, it is difficult to suppress generation of isocyanate gas by heating in melt kneading and molding of the polyester-based resin composition, and the solution viscosity and melt viscosity are liable to increase by the heating, resulting in poor handling properties.

< preparation of carbodiimide Compound (B) >

The method for producing the carbodiimide compound (B) is not particularly limited, and a known method can be used.

The carbodiimide compound (B) is represented by the formula (1) wherein M is 0, i.e., the unit (M) [ NH-CO-O-R ] is not contained⁴-O-CO-NH-R³]In the case of the structure (2), for example, the following synthesis methods (1) to (3) can be mentioned. Among these synthesis methods, the method (2) is preferred from the viewpoint of production efficiency of the carbodiimide compound (B).

(1) A method in which the diisocyanate compound is subjected to a carbodiimidization reaction in the presence of a catalyst to obtain an isocyanate-terminated polycarbodiimide, and then an organic compound (Y) (blocking agent) is added to carry out a blocking reaction

(2) A method of mixing the diisocyanate compound and the organic compound (Y) (blocking agent) and conducting carbodiimidization and blocking in the presence of a catalyst

(3) A method in which the diisocyanate compound is reacted with an organic compound (Y) (blocking agent) to effect a blocking reaction of the isocyanate group, and then carbodiimidization is carried out in the presence of a catalyst

The carbodiimide compound (B) is represented by the formula (1) wherein M is greater than 0, i.e., has the unit (M) [ NH-CO-O-R ]⁴-O-CO-NH-R³]In the case of the structure (2), for example, the following synthesis methods (4) to (6) can be mentioned. Among these synthesis methods, the method (5) is preferred from the viewpoint of production efficiency and the like.

(4) A method comprising subjecting the diisocyanate compound to a carbodiimidization reaction in the presence of a catalyst to obtain an isocyanate-terminated polycarbodiimide, and then adding an organic compound (Y) (a blocking agent) and the diol compound to carry out a urethanation reaction and a blocking reaction

(5) A method of mixing the diisocyanate compound, the diol compound and the organic compound (Y) (blocking agent) and carrying out a urethanation reaction, a carbodiimidization reaction and a blocking reaction in the presence of a catalyst

(6) A method comprising subjecting a part of the diisocyanate compound and the diol compound to a urethanation reaction to obtain an isocyanate-terminated polycarbodiimide into which a urethane bond is introduced, mixing the isocyanate-terminated polycarbodiimide into which a urethane bond is introduced, the remaining part of the diisocyanate compound and an organic compound (Y) (blocking agent), and carrying out a carbodiimidization reaction and a blocking reaction in the presence of a catalyst

The carbodiimidization reaction is preferably a decarboxylation condensation reaction of the diisocyanate compound in the presence of a carbodiimidization catalyst, for example.

Examples of the carbodiimidization catalyst include: phospholene oxides such as 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, and 3-phospholene isomers thereof. Among them, 3-methyl-1-phenyl-2-phosphole-1-oxide is preferable from the viewpoints of reactivity, availability, and the like.

The amount of the carbodiimidization catalyst used is usually preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 0.2 to 1 part by mass, based on 100 parts by mass of the diisocyanate compound.

The decarboxylation condensation reaction of the diisocyanate compound may be carried out in a solvent or without a solvent. Examples of the solvent used include: alicyclic ethers such as tetrahydrofuran, 1, 3-dioxane and dioxolane; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, perchloroethylene, trichloroethane, dichloroethane and the like; cyclohexanone, and the like. These solvents may be used alone, or 2 or more of them may be used in combination.

When the reaction is carried out in a solvent, the concentration of the diisocyanate compound is preferably 5 to 55% by mass, more preferably 5 to 20% by mass.

The reaction temperature of the decarboxylation condensation reaction may be appropriately set according to an appropriate reaction acceleration, a polymerization degree of a carbodiimide group, or the like. The temperature is preferably 20 to 200 ℃, more preferably 30 to 170 ℃, and still more preferably 40 to 150 ℃. When the reaction is carried out in a solvent, the temperature is preferably in the range of 40 ℃ to the boiling point of the solvent.

The reaction time is appropriately set depending on the reaction temperature, the degree of polymerization of the carbodiimide group, and the like. The time is preferably 0.5 to 100 hours, more preferably 1 to 70 hours, and further preferably 2 to 30 hours.

The reaction is preferably carried out in an inert gas atmosphere such as nitrogen or a rare gas.

The reaction temperature of the urethanization reaction and the end-capping reaction is appropriately set within a range in which side reactions can be suppressed and the reaction can be promoted. The temperature is preferably 20 to 200 ℃, more preferably 30 to 170 ℃, and still more preferably 40 to 150 ℃.

The reaction time is appropriately set within a range in which the reaction temperature and side reactions can be suppressed. The time is preferably 0.1 to 20 hours, more preferably 0.5 to 10 hours, and further preferably 1 to 3 hours.

[ organic Compound (C) ]

The organic compound (C) in the polyester resin composition of the present invention is a compound having at least one of an epoxy group and a hydroxyl group.

By adding and mixing such a compound to the polyester resin (a) together with the carbodiimide compound (B), the polyester resin (a) can be provided with more excellent hydrolysis resistance than ever before.

The organic compound (C) is a compound having an epoxy group and/or a hydroxyl group, and among them, an epoxy compound having an epoxy equivalent (formula weight per 1 mole of epoxy group) of 170 to 750 and a hydroxyl compound having a hydroxyl equivalent (formula weight per 1 mole of hydroxyl group) of 170 to 750 are preferable. Of these compounds, 1 kind may be used alone, or 2 or more kinds may be used in combination.

When the epoxy equivalent is 170 or more, the polyester resin composition can be inhibited from increasing in solution viscosity and melt viscosity by heating at the time of melt kneading and molding. When the epoxy equivalent is 750 or less, it is preferable from the viewpoint of imparting good hydrolysis resistance to the polyester-based resin (a).

The epoxy equivalent is more preferably 170 to 500, and still more preferably 180 to 300.

The hydroxyl equivalent can be similarly explained as the epoxy equivalent.

Further, the epoxy equivalent may be determined by a method in accordance with JIS K7236: 2001 by the method described in the above. In addition, the hydroxyl equivalent may be determined by a method according to JIS K1557-1: the hydroxyl value was determined by the method described in 2007.

Examples of the epoxy compound include: bisphenol type epoxy resins such as bisphenol a type, bisphenol F type, bisphenol S type, bisphenol AD type, and tetrabromobisphenol a type; novolac-type epoxy resins such as cresol novolac-type, phenol novolac-type, naphthol novolac-type, bisphenol a novolac-type, bromophenol novolac-type, alkylphenol novolac-type, bisphenol S novolac-type, alkoxy-containing novolac-type, and bromophenol novolac-type. In addition, there may be mentioned: a bifunctional epoxy resin such as a phenol aralkyl type epoxy resin (an epoxide of a Xylok resin), a biphenyl type epoxy resin, a tetramethylbiphenyl type epoxy resin, and a stilbene type epoxy resin, an alicyclic epoxy resin such as a hydrogenated bisphenol a type epoxy resin, a triphenylmethane type epoxy resin, a tetraphenylethane type epoxy resin, a dicyclopentadiene-phenol addition reaction type epoxy resin, a biphenyl-modified novolac type epoxy resin (an epoxide of a polyhydric phenol resin in which phenol nuclei are linked by a dimethylene), a sulfur-containing epoxy resin, a resorcinol diglycidyl ether, a hydroquinone diglycidyl ether, a catechol diglycidyl ether, and a triglycidyl isocyanate.

Examples of the hydroxyl compound include: long chain alkyl alcohols having 12 or more carbon atoms such as lauryl alcohol, cetyl alcohol, and stearyl alcohol. Examples of the compound having an epoxy group and a hydroxyl group include: phenoxy resins such as bisphenol A type phenoxy resins, bisphenol A/bisphenol F type copolymerized phenoxy resins, phosphorus-modified phenoxy resins, and the like.

Among them, from the viewpoint of ease of handling when adding and mixing to the polyester resin composition, the organic compound (C) is preferably a compound which is solid at 25 ℃ and 1 atm, i.e., at normal temperature and pressure.

The content of the organic compound (C) in the polyester resin composition is 0.1 to 10.0, preferably 0.2 to 9.0, and more preferably 0.3 to 8.0, in terms of the mass ratio of the organic compound (C) to the carbodiimide compound (B).

When the mass ratio is less than 0.1, the hydrolysis resistance of the resulting polyester resin tends to decrease with time. On the other hand, when the mass ratio exceeds 10.0, the physical properties of the polyester-based resin (a) are impaired, and hydrolysis resistance cannot be sufficiently imparted.

[ Process for producing polyester resin composition ]

The polyester resin composition can be obtained by melt-kneading a polyester resin (A), a carbodiimide compound (B) and an organic compound (C). In this case, a mixture in which the polyester resin (a) and the carbodiimide compound (B) are mixed in advance may be melt-kneaded, or the carbodiimide compound (B) may be added to the molten polyester resin (a) and melt-kneaded. Further, the polyester resin (a) may be melt-kneaded with a resin compound such as a temporarily prepared master batch by any of these methods.

The polyester-based resin composition of the present invention, by adding the carbodiimide compound (B) and the organic compound (C), is less likely to generate isocyanate gas even when melt-kneaded as described above, and is capable of preventing deterioration of the working environment. In addition, since the increase in melt viscosity is suppressed, the operation efficiency of melt kneading can be improved, and the production efficiency is also excellent.

In addition, in the polyester-based resin (a), in addition to the carbodiimide compound (B) and the organic compound (C), known additives suitable for polyester-based resins, such as an antioxidant, a flame retardant, an ultraviolet absorber, and a colorant, may be added within a range not to impair the effects of the present invention. That is, the polyester resin composition may contain the above-mentioned additives as required from the viewpoint of performance required for its use.

In this case, the total content of the polyester-based resin (a), the carbodiimide compound (B), and the organic compound (C) in the polyester-based resin composition is preferably 90% by mass or more, more preferably 92% by mass or more, and still more preferably 95% by mass or more.

The melt kneading method is not particularly limited, and may be carried out using a known kneader. Examples of the kneading machine include a single-screw extruder, a twin-screw extruder, a roll mixer, and the like.

The temperature during melt kneading is appropriately adjusted depending on the kind of the polyester resin (A), and is usually about 150 to 350 ℃.

The polyester resin product using the polyester resin composition can be produced by a known molding method such as an injection molding method, a film molding method, a blow molding method, or a foam molding method. The polyester resin (A) may be molded into various forms such as a film, a sheet, and a block at a temperature not lower than the melting temperature thereof.

The polyester resin product molded in this manner using the polyester resin composition of the present invention is excellent in hydrolysis resistance.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

[ Synthesis of carbodiimide Compound (B) ]

Details of each raw material used in the following synthesis examples are shown below.

< diisocyanate Compound >

A mixture of 2,4 '-MDI (54 mol%) and 4, 4' -MDI (46 mol%): millionate NM, manufactured by Tosoh corporation

Mixture of 2,4-TDI (80 mol%) and 2,6-TDI (20 mol%): "Cosmonate (registered trademark) T-80", manufactured by Mitsui chemical SKC polyurethane Co., Ltd

4, 4' -MDI: "Millionate MT", manufactured by Tosoh corporation

HMDI: dicyclohexylmethane-4, 4' -diisocyanate, "Desmodur (registered trademark) W", product of Sunghua Corsia polyurethane Co., Ltd

< organic Compound (Y) (end-capping agent) >)

IPA: isopropyl alcohol, manufactured by Kanto chemical Co., Ltd

OA: 2-Ethyl hexanol (octanol), manufactured by Mitsubishi chemical corporation

< diol Compound >

Polyester polyols: "Maximol (registered trademark) RFK-505", manufactured by Kawasaki Kazaki Kaisha

(Synthesis example 1)

100 parts by mass of a mixture of 2,4 '-MDI (54 mol%) and 4, 4' -MDI (46 mol%), 6.9 parts by mass of IPA and 0.5 part by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst were charged into a reaction vessel equipped with a reflux tube and a stirrer, and mixed under stirring at 110 ℃ for 2 hours under a nitrogen stream.

The wavelength of 2270cm was confirmed by infrared absorption (IR) spectrometry (measuring apparatus: Fourier transform infrared spectrophotometer "FTIR-8200 PC", manufactured by Shimadzu corporation, the same shall apply hereinafter)^-1Absorption peaks of the isocyanate groups before and after the disappearance, and a carbodiimide compound (B1) (m is 0, and n is 6) was obtained.

(Synthesis example 2)

100 parts by mass of a mixture of 2,4 '-MDI (54 mol%) and 4, 4' -MDI (46 mol%), 6.9 parts by mass of IPA and 25.3 parts by mass of polyester polyol were charged into a reaction vessel equipped with a reflux tube and a stirrer, and mixed under stirring at 60 ℃ for 1 hour under a nitrogen stream.

Subsequently, 0.5 part by mass of 3-methyl-1-phenyl-2-phosphole-1-oxide was added as a carbodiimidization catalyst, and the mixture was stirred and mixed at 100 ℃ for 3 hours.

The wavelength of 2270cm was confirmed by IR spectroscopy^-1Absorption peaks of the isocyanate groups before and after the disappearance, and a carbodiimide compound (B2) (m is 1, and n is 5) was obtained.

(Synthesis examples 3 and 4)

Carbodiimide compounds (B3) and (B4) were obtained in the same manner as in synthesis example 2, except that the raw material compositions in synthesis example 2 were changed as shown in table 1 below.

(Synthesis example 5)

A carbodiimide compound (B5) (aliphatic carbodiimide) was obtained in the same manner as in synthesis example 1, except that the diisocyanate compound was replaced with HMDI in synthesis example 1 and the raw material composition shown in table 1 below was used.

[ Table 1]

[ preparation of polyester resin composition ]

Details of the raw materials used in the following examples and comparative examples are shown below. Further, the epoxy equivalent and the hydroxyl equivalent of the organic compound (C) described below are calculated values or catalog values.

< polyester resin (A) >)

(A1) PBT resin: NOVADURAN (registered trademark) 5010L, manufactured by Mitsubishi engineering plastics corporation

(A2) PET resin: TRN-8550FF, manufactured by Dijinghua Kabushiki Kaisha

< carbodiimide Compound (B) >

(B1) (B5): carbodiimides prepared in Synthesis examples 1 to 5

(B6) Poly (1,3, 5-triisopropylphenylene-2, 4-carbodiimide): "Stabaxol (registered trademark) P100", manufactured by Rhine chemical Co., Ltd

< organic Compound (C) >)

(C1) Cresol novolac type epoxy resin: "EPICLON (registered trademark) N-695", available from DIC corporation, epoxy equivalent 215

(C2) Bisphenol a type epoxy resin: "EPICLON (registered trademark) 860" manufactured by DIC corporation, epoxy equivalent 240

(C3) Stearyl alcohol: "KALCOL (registered trademark) 8098", Kao corporation, hydroxyl equivalent 270

(C4) Phenoxy resin: "YP-50S", Nichika chemical & materials, hydroxyl equivalent 284

(example 1-1)

After 98.5 parts by mass of a PBT resin was melted at 250 ℃ using a laboratory mixer ("segment mixer KF 70V", manufactured by Toyo Seiki Seisaku-Sho K.K., Laboplast Mill (registered trademark), the same shall apply hereinafter), 1.0 part by mass of a carbodiimide compound (B1) and 0.5 part by mass of an organic compound (C1) were added and kneaded for 3 minutes to prepare a polyester-based resin composition (PBT resin composition).

(examples 1-2 to 1-26 and comparative examples 1-2 to 1-13)

Polyester resin compositions (PBT resin compositions) were prepared in the same manner as in example 1-1, except that the carbodiimide compound (B) and the organic compound (C) described in Table 2 below were each changed in example 1-1.

Comparative example 1-1

A blank of a PBT-only resin to which the carbodiimide compound (B) and the organic compound (C) were not added was defined as comparative example 1-1.

(example 2-1)

After 98.5 parts by mass of a PET resin was melted at 280 ℃ using a laboratory mixer, 1.0 part by mass of a carbodiimide compound (B1) and 0.5 part by mass of an organic compound (C1) were added and kneaded for 3 minutes to prepare a polyester resin composition (PET resin composition).

(examples 2-2 to 2-26 and comparative examples 2-2 to 2-13)

Polyester resin compositions (PET resin compositions) were prepared in the same manner as in example 2-1, except that the carbodiimide compound (B) and the organic compound (C) described in table 3 below were changed in example 2-1.

Comparative example 2-1

A blank of only a PET resin to which the carbodiimide compound (B) and the organic compound (C) were not added was defined as comparative example 2-1.

[ measurement evaluation ]

The polyester resin compositions obtained in the examples and comparative examples were subjected to the evaluation of the following items. The results of these measurements are summarized in tables 2 and 3 below.

< production of isocyanate gas >

The melt-kneaded polyester-based resin composition was heated at 300 ℃ for 20 minutes, and quantitative analysis of the produced isocyanate gas was carried out by a gas chromatography mass spectrometer (GC-MS) ("6890 GC system", manufactured by Agilent technologies Co., Ltd.).

The smaller the amount of the isocyanate gas detected (generated amount) is, the more preferable. The evaluation results shown in tables 2 and 3 below are based on the following evaluation criteria.

[ evaluation criteria ]

A: the detected amount of isocyanate gas is less than 500ppm

B: the detected amount of isocyanate gas is 500ppm or more and less than 1000ppm

C: the detected amount of isocyanate gas is 1000ppm or more

< hydrolysis resistance >

(1) PBT resin composition

The melt-kneaded PBT resin composition was subjected to plate pressing at 250 ℃ to form a sheet having a thickness of about 300 μm, and then a rectangular sheet having a width of 10mm and a length of 70mm was produced.

The tensile strength of the rectangular sheet was measured by a tensile tester ("3365", manufactured by instron, 20. + -. 5 ℃ C. (room temperature), the same shall apply hereinafter).

The rectangular sheets were subjected to a wet heat treatment in a highly accelerated life tester ("EHS-210M", manufactured by ESPEC Co., Ltd.; constant temperature and humidity apparatus: temperature 121 ℃ and relative humidity 100% ") and the tensile strength of each rectangular sheet was measured by a tensile tester 72 hours after the start of the wet heat treatment, 120 hours after the end of the wet heat treatment and 168 hours after the end of the wet heat treatment.

The average value of the measured values of the tensile strength of each 5 rectangular sheets was calculated before, after 72 hours, after 120 hours and after 168 hours of the wet heat treatment.

The ratio of the average value of the tensile strength after the lapse of 72 hours to the average value (reference value) of the tensile strength before the wet heat treatment was calculated as the strength retention rate after the lapse of 72 hours. The respective strength retention rates were determined in the same manner for the test pieces after 120 hours and 168 hours.

The strength retention ratio is a value which becomes an evaluation index of hydrolysis resistance of the polyester-based resin, and a larger value means that the tensile strength is maintained even after the wet heat treatment, and if a value after a longer period of time is large, it can be said that the hydrolysis resistance of the polyester-based resin is more excellent.

(2) PET resin composition

The melt-kneaded PET resin composition was subjected to plate pressing at 280 ℃ to form a sheet having a thickness of about 300 μm, and then a rectangular sheet having a width of 10mm and a length of 70mm was prepared.

In the evaluation of the hydrolysis resistance of the PBT resin composition of the above (1), each strength retention ratio was determined in the same manner except that the time for measuring the tensile strength of each rectangular sheet was changed to 40 hours, 72 hours, and 96 hours from the start of the moist heat treatment.

[ Table 2]

[ Table 3]

As is apparent from the measurement and evaluation results shown in tables 2 and 3, in the polyester resin composition of the present invention, by adding the carbodiimide compound (B) and the organic compound (C) in combination, it is possible to suppress generation of isocyanate gas due to heating at the time of melt kneading and molding processing, and to obtain a polyester-based resin excellent in hydrolysis resistance. Particularly, the PBT resin is excellent in the effect of improving the hydrolysis resistance.

Claims

1. A polyester resin composition comprising a polyester resin (A), a carbodiimide compound (B) represented by the following formula (1), and an organic compound (C) having at least one of an epoxy group and a hydroxyl group,

the content of the carbodiimide compound (B) is 0.1 to 10.0 parts by mass relative to 100 parts by mass of the total of the polyester resin (A), the carbodiimide compound (B) and the organic compound (C);

the mass ratio of the organic compound (C) to the carbodiimide compound (B) is 0.1 to 10.0;

[ chemical formula 1]

In the formula, R¹And R²Each independently is a residue obtained by removing 1 functional group reactive with an isocyanate group from an organic compound (Y) having the functional group;

R³a 2-valent residue obtained by removing 2 isocyanate groups from a diisocyanate compound; the diisocyanate compound has a benzene-based aromatic ring directly bonded to the isocyanate group, and has no substituent at both ortho-positions of the isocyanate group of the benzene-based aromatic ring; plural R³Are the same or different from each other;

R⁴a 2-valent residue obtained by removing 2 hydroxyl groups from a diol compound; r⁴When there are plural, each R⁴Are the same or different from each other;

the organic compound (Y) is one or more selected from monohydric alcohol, monoamine, monocarboxylic acid and acid anhydride;

X¹and X²Each independently is a bond formed by a reaction of the functional group of the organic compound (Y) with the isocyanate group of the diisocyanate compound;

m is a number of 0 to 50, and n is a number of 1 to 50.

2. The polyester resin composition according to claim 1, wherein the organic compound (C) is at least one selected from the group consisting of an epoxy compound having an epoxy equivalent of 170 to 750 and a hydroxyl compound having a hydroxyl equivalent of 170 to 750.

3. The polyester resin composition according to claim 1 or 2, wherein the organic compound (C) is a solid at 25 ℃ under 1 atmosphere.

4. The polyester-based resin composition according to any one of claims 1 to 3, wherein the diisocyanate compound is at least one selected from the group consisting of p-phenylene diisocyanate, toluene diisocyanate, tolidine diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate.

5. The polyester resin composition according to any one of claims 1 to 4, wherein the organic compound (Y) is a monohydric alcohol.

6. The polyester-based resin composition according to any one of claims 1 to 5, wherein the diol compound is one or more selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols and polyurethane polyols.

7. The polyester-based resin composition according to any one of claims 1 to 6, wherein the polyester-based resin (A) is one or more selected from the group consisting of polyethylene terephthalate, polybutylene succinate, polylactic acid and polyhydroxyalkanoic acid.