JP2008163311A - Thermosetting oxetane composition - Google Patents

Abstract

The present invention provides a thermosetting oxetane composition excellent in rapid curability and a cured product having excellent mechanical properties.
The present invention relates to a curing agent selected from the group consisting of (A) an oxetane compound, (B) an organic carboxylic acid, an organic carboxylic acid anhydride, and an organic carboxylic acid ester, and (C) a curing that is a rare earth Lewis acid. A thermosetting oxetane composition comprising a catalyst is provided. Furthermore, this invention provides the hardened | cured material obtained by heat-hardening the said thermosetting oxetane composition. The composition of the present invention is sufficiently cured at a low temperature and in a short time and has a high curing rate. The obtained cured product is excellent in mechanical properties (for example, tensile strength, elasticity, surface hardness, bending strength) and durability (for example, solvent resistance, weather resistance).
[Selection figure] None

Description

  The present invention relates to a thermosetting oxetane composition and a cured product thereof.

  The light / thermosetting oxetane resin using a cationic curing agent has been actively studied in the fields of a hard coating agent on the surface of an article, a photocurable adhesive, a casting resin, and the like.

  Japanese Patent Application Laid-Open No. 11-209599 (Patent Document 1) describes a casting resin useful for sealing an optical element or the like, which comprises a compound having an oxetane ring and a photocationic polymerization initiator. JP-A-8-85775 (Patent Document 2) describes a resin composition suitable for the surface coating of a steel sheet, comprising a compound having 1 to 4 oxetane rings and a photocationic polymerization initiator. ing. However, such a cationically curable resin is a resin obtained by homopolymerizing an oxetane compound or copolymerizing with an epoxy resin, and like a normal epoxy resin composition, a curing agent is added to impart characteristics. It has the disadvantage that it cannot be used together. In addition, the high price of oxetane compounds prevents the generalization of thermosetting resins by cationic curing of oxetane.

  On the other hand, oxetane is known to react with various protic compounds, and Nishikubo et al. (Journal of Polymer Science, Part A; Polymer Chemistry, vol. 37) , 2781-2790 (1999) (Non-Patent Document 1)). According to this document, it is disclosed that a bifunctional phenol and a bifunctional oxetane compound cause gelation under a specific catalyst.

  Further, it is known that an oxetane compound is polyadded with a carboxylic acid and then causes a polycondensation reaction. In JP-A-11-43540 (Patent Document 3), 1 to 4 oxetane rings are contained in a molecule. The technique which makes a thermosetting resin by adding a quaternary onium salt as a hardening accelerator to the compound which has and the compound which has a carboxyl group is disclosed. However, the oxetane resin composition using these quaternary onium salts has a very slow curing rate, requires a high temperature for curing, or requires a long time for curing, and is practical as a thermosetting resin. It was scarce.

JP 2003-012794 (Patent Document 4) proposes a curable resin obtained by adding a Lewis acid or an organic boron compound as a curing catalyst to an oxetane compound and a carboxylic acid anhydride. The metal used is a base metal such as zinc, and sufficient curability is not obtained.
Japanese Patent Laid-Open No. 11-209599 JP-A-8-85775 Japanese Patent Laid-Open No. 11-43540 JP 2003-012794 A Journal of Polymer Science, Part A; Polymer Chemistry, vol. 37, 2781-2790 (1999)

  An object of the present invention is to provide a thermosetting oxetane composition excellent in curability, particularly fast curability, and a cured product having excellent mechanical properties and durability.

  In view of the current situation of thermosetting oxetane resins, the present inventors have intensively studied, and as a result of using oxetane compounds, carboxylic acids, and specific curing catalysts, exhibit various characteristics depending on the type of curing agent. The present invention succeeded in obtaining a resin composition having sufficient curability that can be used and can be practically used, for example, at a temperature of 150 ° C. or lower and capable of being sufficiently cured within 30 minutes.

The present invention
(A) an oxetane compound,
Provided is a thermosetting oxetane composition comprising (B) a curing agent selected from the group consisting of organic carboxylic acids, organic carboxylic acid anhydrides and organic carboxylic acid esters, and (C) a curing catalyst which is a rare earth Lewis acid. .
Furthermore, this invention provides the hardened | cured material obtained by heat-hardening the said thermosetting oxetane composition.

  The composition of the present invention is sufficiently cured at a low temperature and in a short time and has a high curing rate. The obtained cured product is excellent in mechanical properties (for example, tensile strength, elasticity, surface hardness, bending strength) and durability (for example, solvent resistance, weather resistance).

［式中、Ｒはｎ価の有機基を表し、
Ｒ₁は水素原子または１価の脂肪族基であり、１分子中のｎ個のＲ₁は同一であっても異なっていてもよく、
ｎは１以上の整数である。］
で示される化合物である。
Ｒの例は、酸素原子を有していてもよい脂肪族基（例えば炭素数１〜２０）、芳香族基（例えば炭素数６〜２０）または芳香脂肪族基（例えば炭素数７〜３０）、ヒドロキシアルキル（例えば炭素数１〜２０）基である。Ｒ₁である脂肪族基は、例えば、炭素数１〜３０であってよく、アルキル基であることが好ましい。ｎは１または２であることが好ましい。 Various oxetane derivatives can be used as the oxetane compound (A). Examples of oxetane compounds (A) have the formula:

[Wherein R represents an n-valent organic group,
R ₁ is a hydrogen atom or a monovalent aliphatic group, and n R _{1 in} one molecule may be the same or different,
n is an integer of 1 or more. ]
It is a compound shown by these.
Examples of R include an aliphatic group (for example, having 1 to 20 carbon atoms), an aromatic group (for example, 6 to 20 carbon atoms) or an araliphatic group (for example, 7 to 30 carbon atoms) which may have an oxygen atom. , A hydroxyalkyl (for example, C1-20) group. The aliphatic group that is R ₁ may have, for example, 1 to 30 carbon atoms, and is preferably an alkyl group. n is preferably 1 or 2.

Specific examples of the oxetane compound (A) include
4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP), 3-ethyl-3-hydroxymethyloxetane (EHO), 1,4-bis [{(3-ethyl-3- Oxetanyl) methoxy} methyl] benzene (XDO), di [1-ethyl (3-oxetanyl)] methyl ether (DOX), di [1-ethyl (3-oxetanyl)] methyl ether (DOE), 1,6-bis [(3-Ethyl-3-oxetanyl) methoxy] hexane (HDB), 9,9-bis [2-methyl-4- {2- (3-oxetanyl)} butoxyphenyl] fluorene, 9,9-bis [4 -Bifunctional oxetane compounds such as bifunctional oxetane compounds such as [2- {2- (3-oxetanyl)} butoxy] ethoxyphenyl] fluorene and oxetaneated novolak resins Thing, and the like. These compounds are readily available on the market.

及び3-エチル-3-ヒドロキシメチルオキセタン（ＥＨＯ）：

が特に好ましい。
オキセタン化合物（Ａ）は、１種単独または２種以上の混合物であってよい。 4,4 '-(3-Ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP):

And 3-ethyl-3-hydroxymethyloxetane (EHO):

Is particularly preferred.
The oxetane compound (A) may be a single type or a mixture of two or more types.

  The curing agent (B) is an organic carboxylic acid, an organic carboxylic acid anhydride or an organic carboxylic acid ester. The curing agent (B) is preferably a compound having two or more carboxyl groups or ester groups in the molecule, or a compound having one or more acid anhydride groups in the molecule.

In the organic carboxylic acid, the number of carbon atoms is preferably 1-30. The organic carboxylic acid is an aliphatic carboxylic acid (for example, having 1 to 10 carbon atoms), an alicyclic carboxylic acid (for example, having 4 to 10 carbon atoms), an aromatic carboxylic acid (for example having 6 to 18 carbon atoms) or an araliphatic carboxylic acid. It is preferable that it is (for example, C7-20).
Specific examples of the organic carboxylic acid include carbonic acid, maleic acid, fumaric acid, succinic acid, hexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, adipic acid, oxalic acid, terephthalic acid and other dibasic acids, trimellit Examples thereof include polybasic acids having 5 or more carboxylic acid groups in one molecule, such as tribasic acids such as acids, tetrabasic acids such as pyromellitic acid, and polyacrylic acid derivatives. Specific examples of organic carboxylic acid anhydrides and organic carboxylic acid esters are anhydrides and esters of specific examples of these organic carboxylic acids.

  The organic carboxylic acid ester is an ester of an organic carboxylic acid and an alcohol. The alcohol may have 1 to 20 carbon atoms, for example 1 to 10, and is a monovalent to pentavalent alcohol, particularly a monovalent alcohol. Examples of the alcohol include saturated or unsaturated aliphatic alcohols, alicyclic alcohols, aromatic alcohols, and araliphatic alcohols. Specific examples of alcohols are methanol, ethanol, propanol, butanol, hexanol, octanol, nonanol, decanol, dodecanol, tridecanol, hexadecanol, octadecanol, icosanol, allyl alcohol, phenol, naphthol, benzyl alcohol, octylphenol, nonylphenol. is there.

  The curing agent is not limited to these specific examples, and there is no limitation on the type of the curing agent as long as it is a compound having a carboxyl group, a carboxylic acid anhydride group or a carboxylic acid ester group having reactivity with the oxetane compound.

As the curing agent, acid anhydrides, particularly dibasic acid anhydrides are particularly preferred. Specific examples of acid anhydrides include maleic anhydride, phthalic anhydride, and cyclohexanedicarboxylic anhydride (eg, 1,2-cyclohexanedicarboxylic acid). Anhydride).
When a carboxylic acid anhydride is used, the blending amount is determined under the condition that one acid anhydride group (1 equivalent) corresponds to two carboxyl groups (2 equivalents).

The curing agent (B) has 1.2 to 2.5 carboxyl groups (or ester groups) of the curing agent (B) per oxetane ring (1 equivalent) of the oxetane compound (A) (1.2 to 1.2). It is preferable to mix | blend so that it may become 2.5 equivalent), and it is more preferable to mix | blend so that it may be 1.5-2 pieces (1.5-2.0 equivalent). When the amount of the curing agent is within this range, unreacted groups are not generated, the crosslinked structure becomes dense, and the properties such as the water absorption rate of the resin are further improved.
The curing agent (B) may be a single type or a mixture of two or more types.

  In order for the resin composition of the present invention to exhibit excellent rapid curability, it is essential to use a curing catalyst (C). The curing catalyst is a compound that accelerates the reaction between the oxetane compound (A) and the curing agent (B), and is a rare earth Lewis acid. “Lewis acid” means a substance capable of accepting an electron pair, as defined by GN Lewis. The rare earth Lewis acid is a Lewis acid containing a rare earth metal element.

  The rare earth metal element is generally a lanthanoid element or an actinoid element, particularly a lanthanoid element. Specific examples of rare earth metal elements that are lanthanoid elements include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium ( Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). The rare earth metal element is particularly preferably lanthanum (La), samarium (Sm), europium (Eu) or ytterbium (Yb).

  Examples of rare earth Lewis acids include organic acid ester salts of rare earth metal elements, organometallic compounds in which rare earth metal elements and carbon atoms are bonded, metal alcoholates, metal phenolates, metal carboxylates, and metal complexes.

Examples of rare earth Lewis acids have the general formula:
MX _m · L _n
[Wherein M is a metal ion of a rare earth metal element,
X is an anion,
L is a neutral molecule with coordinating power to M,
m is the valence number of the metal M,
n is an integer of 0-10. ]
It may be a Lewis acid represented by

M is a metal ion and is composed of a rare earth metal element.
As the anion X, a halogen anion, a triflate (that is, trifluoromethanesulfonate) [(OTf) ₃ ] anion, an alkanedionate anion (carbon number of alkane) which may be substituted with a fluorine atom such as an acetylacetonate anion Examples thereof include 1-30), perfluoroalkylsulfonate anion, bis (perfluoroalkylsulfonyl) amide anion, tris (perfluoroalkylsulfonyl) methide anion and the like.
The neutral molecule L may be coordinated. The neutral molecule L is a molecule that coordinates to M and includes, for example, ethers such as water and diethyl ether. The number n is 0-10, for example 1-6.
The rare earth Lewis acid has the formula:
MX _m
[Wherein, M, X and m are as defined above. ]
It is preferable that it is a compound shown by these.

Preferred examples of rare earth Lewis acids include lanthanum triflate, lanthanum acetylacetonate, lanthanum tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedio Natto), europium triflate, europium acetylacetonate, europium tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate), ytterbium triflate Ytterbium acetylacetonate, ytterbium tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate), samarium triflate, samarium acetylacetonate, Samarium tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) and the like.
Particularly preferred are lanthanum (La), samarium (Sm), europium (Eu) or ytterbium (Yb) triflate or acetylacetonate.
The curing catalyst (C) may be a single type or a mixture of two or more types.

  The amount of the curing catalyst (C) is 0.001 to 5 parts by weight, particularly 0.01 to 1 part by weight, with respect to a total of 100 parts by weight of the oxetane compound (A) and the curing agent (B). Although it is preferable, it may be outside this range as long as the properties of the resin composition of the present invention are not impaired.

  The thermosetting oxetane composition of this invention may contain additives, such as a coupling agent, a mold release agent, a lubricant, a filler, and antioxidant, as needed. The amount of the additive may be 100 parts by weight or less, for example, 70 to 10 parts by weight with respect to a total of 100 parts by weight of the oxetane compound (A) and the curing agent (B).

The composition of the present invention can be produced by mixing the components (A), (B) and (C). The composition can be cured by heating. The curing temperature is 170 ° C. or lower, preferably 150 ° C. or lower, particularly 140 ° C. or lower. Generally, the lower limit of the curing temperature is 90 ° C. The curing time is generally 10 minutes to 5 hours, in particular 30 minutes to 4 hours. A general method of kneading by heating with equipment such as a heating kneader or a hot roll can be applied.
By curing the composition, a polymer having a repeating unit derived from the oxetane compound (A) and a repeating unit derived from the curing agent (B) is obtained. The cured product is solid at room temperature (25 ° C.) to 100 ° C., particularly 30 ° C.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by an Example.
In the following, “%” and “parts” represent “% by weight” and “parts by weight” unless otherwise specified.

In the following, the physical properties were measured as follows.
The appearance of the curable cured product (polymer) was judged visually.
Good: Solidified sufficiently.
Bad: Insufficient solidification.
Hardness Hardness cured (surface hardness) was measured according to JIS K7215 using a durometer.

Tensile test A cured product having a thickness of 1 mm was cut into a width of 10 mm and a length of 100 mm, and evaluated using a universal testing machine (Tensilon) at a distance between chucks of 40 mm and a tensile speed of 1 mm / min.
Solvent resistance is evaluated by immersing the solvent-resistant cured product in each of five solvents of acetone, methanol, toluene, ethyl acetate, and water at room temperature (25 ° C) for 70 hours and measuring the change in weight. did.
Good: Almost no change in weight in all solvents (weight change less than 0.5%)
Bad: There is a weight change with any solvent (weight change 3% or more)

Examples 1-4
The oxetane compound (A), curing agent (B) and curing catalyst (C) shown in Table 1 were mixed to obtain a resin composition. If necessary, it was cooled to room temperature (25 ° C.) during mixing.
The resin composition (about 25 g) was charged into an aluminum container (a cylindrical container having a circular bottom surface with a diameter of 13.4 cm). The aluminum container was placed in an oven set at a temperature of 140 ° C. and heated for 30 minutes. The physical properties (hardness, tensile strength, etc.) of the obtained cured product were measured. The results are shown in Table 1.

各成分の量の単位は重量部である。

The unit of the amount of each component is parts by weight.

In Table 1, the meanings of the abbreviations are as follows.
OXBP: 4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl EHO: 3-ethyl-3-hydroxymethyloxetane MA: maleic anhydride CHA: 1,2-cyclohexanedicarboxylic anhydride
Sm (OTf) ₃ : Samarium triflate

Example 5
4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP) 41 parts, 3-ethyl-3-hydroxymethyloxetane (EHO) 11.6 parts, maleic anhydride (MA) 23.4 parts and Sm (OTf) ₃ (Curing catalyst) 0.07 part was mixed to obtain a resin composition.
The resin composition (about 25 g) was charged into an aluminum container (a cylindrical container having a circular bottom surface with a diameter of 13.4 cm). The aluminum container was placed in an oven set at a temperature of 140 ° C. and heated for 30 minutes. The obtained cured product was subjected to a three-point bending test. The results are shown in Table 2.
The measuring method of the three-point bending test was as follows.
A cured product having a thickness of 1 mm was cut into a sample having a width of 20 mm and a length of 40 mm to obtain a test piece. Using a universal testing machine (Tensilon), the three-point bending strength was evaluated at an edge span of 32 mm and a speed of 2 mm / min. In the three-point bending test, the elastic modulus, maximum point stress, breaking strain, maximum strain, and breaking stress were measured.

Examples 6-17 and Comparative Examples 1-6
In the same manner as in Example 1, compositions were prepared using the components shown in Tables 3 to 5, and then cured. The curability was evaluated visually. The results are shown in Tables 3-5.

各成分の量の単位はミリモルである。

The unit of the amount of each component is millimolar.

各成分の量の単位はミリモルである。

The unit of the amount of each component is millimolar.

各成分の量の単位はミリモルである。

The unit of the amount of each component is millimolar.

In Tables 3 to 5, the meanings of the abbreviations are as follows.
OXBP: 4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl EHO: 3-ethyl-3-hydroxymethyloxetane DOE: di [1-ethyl (3-oxetanyl)] methyl ether XDO: 1 , 4-bis [{(3-ethyl-3-oxetanyl) methoxy} methyl] benzene HDB: 1,6-bis [(3-ethyl-3-oxetanyl) methoxy] hexane MA: maleic anhydride CHA: 1,2 -Cyclohexanedicarboxylic anhydride PA: phthalic anhydride
Sm (OTf) ₃ : Samarium triflate
Yb (OTf) ₃ : Ytterbium triflate
La (OTf) ₃ lantern triflate
La (acac) ₃ : Lanthanum acetylacetonate
Eu (FOD) ₃ : Europium tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)
ZnI ₂ : Zinc iodide
ZnCl ₂ : Zinc chloride
Cu (OTf) ₂ : Copper triflate

Example 18
Curing of OXBP / EHO / SA Composition and Evaluation of Cured Product 4,4 ′-(3-Ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP) 35.4 mmol, 3-ethyl-3-hydroxymethyloxetane (EHO 37.8 mmol, 62.7 mmol of succinic anhydride (SA), and samarium trifluoromethanesulfonate (0.050 mmol) were charged in an aluminum container and heated at 145 ° C. for 3 hours. The same reaction was performed 6 times, and the mechanical properties of the obtained cured products were evaluated by a plastic tensile test method based on JIS 7113. The results are shown in Table 6.

Example 19
Yield and evaluation of cured product in oxetane / curing agent / curing catalyst After the oxetane compound (A) and curing agent (B) shown in Table 7 were charged into an aluminum container and slowly dissolved at low temperature on a hot plate, A curing catalyst (C) dissolved in methanol was added. After heating for several seconds on a hot plate, the plate was placed in an oven set at a predetermined temperature in Table 8 and heated for 4 hours. The physical properties (hardness) of the obtained cured product were measured. The results are shown in Table 8.

（各成分の量の単位はミリモルである。）

(The unit of the amount of each component is millimole.)

In Table 7, the meanings of the abbreviations are as follows.
OXBP: 4,4 ′-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl HDB: 1,6-bis [(3-ethyl-3-oxetanyl) methoxy] hexane MT: dimethyl terephthalate MS: succinic acid Dimethyl DPC: Diphenyl carbonate DMO: Dimethyl oxalate

  As can be seen from Tables 1 to 7, the thermosetting oxetane composition of the present invention exhibits extremely excellent curing characteristics in practical use. Further, as can be seen from Tables 1 and 6, the cured product obtained by the present invention has excellent mechanical properties and solvent resistance.

Claims (8)

(A) an oxetane compound,
(B) A thermosetting oxetane composition comprising a curing agent selected from the group consisting of organic carboxylic acids, organic carboxylic acid anhydrides and organic carboxylic acid esters, and (C) a curing catalyst which is a rare earth Lewis acid. The oxetane compound (A) has the formula:

[Wherein R represents an n-valent organic group,
R ₁ is a hydrogen atom or a monovalent aliphatic group, and n R _{1 in} one molecule may be the same or different,
n is an integer of 1 or more. ]
The thermosetting oxetane composition of Claim 1 which is a compound shown by these.   The oxetane compound (A) is at least one selected from the group consisting of 4,4 '-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl and 3-ethyl-3-hydroxymethyloxetane. The thermosetting oxetane composition described in 1.   The thermosetting oxetane composition according to claim 1, wherein the curing agent (B) is an anhydride of a dibasic acid. The curing catalyst (C) has the general formula:
MX _m · L _n
[Wherein M is a metal ion of a rare earth metal element,
X is an anion,
L is a neutral molecule with coordinating power to M,
m is the valence number of the metal M,
n is an integer of 0-10. ]
The thermosetting oxetane composition according to claim 1, which is a Lewis acid represented by the formula:   The thermosetting oxetane composition according to claim 1, wherein the curing catalyst (C) contains at least one rare earth metal element selected from the group consisting of lanthanum, samarium, europium and ytterbium.   The thermosetting oxetane composition according to claim 1, wherein the curing catalyst (C) is lanthanum (La), samarium (Sm), europium (Eu) or ytterbium (Yb) triflate or acetylacetonate.   A cured product obtained by curing the thermosetting oxetane composition according to claim 1 by heating.