JPH08225648A - Curable composition and production of thick-wall molding therefrom - Google Patents

Abstract

PURPOSE: To obtain a curable composition which can give a thick-wall molding which retains the properties of a ladder polysiloxane by incorporating a specific ladder silsesquioxane polymer and a titanium-based catalyst. CONSTITUTION: A mixture of 100 pts.wt. ladder silsesquioxane polymer (A) represented by formula I [wherein R<1> is a monovalent hydrocarbon group; R<2> is a monovalent aromatic hydrocarbon group; R<3> is H or a monovalent hydrocarbon group; and l, m, and n each is 0 or a positive integer, provided that 2<=(1+m+n)] and having a number-average mol.wt. of 500 or higher, 0.1-20 pts.wt. titanium-based catalyst (B), 5-50 pts.wt. polyfunctional crosslinking agent (C) represented by formula II (wherein R<4> is a monovalent hydrocarbon group and k is an integer of 1-7), 5-30 pts.wt. silica crosslinking agent (D), and water (E) in an amount of 10-60mol% based on the alkoxy groups of the component (C) is dissolved in an organic solvent to obtain the curable composition, the amount of the solvent being 20-200ml per 100g of the component (A). This composition is cured by heating at a controlled rate to obtain the molding having a thickness of 0.5mm or larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition containing a silsesquioxane ladder polymer as a main component, which can be cured by heating, and a method for producing a thick molded product using the curable composition.

[0002]

2. Description of the Related Art Organopolysilsesquioxane is a ladder-type polysiloxane having a ladder-like structure. Since it exhibits excellent properties such as heat resistance, hardness, and wear resistance, it is used as a coating material and electrical insulation film. Has been done. However, in spite of having such characteristics, it is not only brittle, but since the curing of such ladder-type polysiloxane is due to a condensation reaction that produces water, alcohol, etc., it forms a film thickness above a certain level. It is extremely difficult to do so, and it is used only as a thin film or a coating film.

Various compounds such as acids, alkalis and amines are known as condensation catalysts for general polysiloxanes, and titanate is one of them. For example, there is a technique using titanium chelate as a curing catalyst for polysiloxane (Japanese Patent Laid-Open No. 4-293962), which aims at an effect on room temperature curing property and interfacial peeling property from an adhesive surface. However, no technique has so far been found to dramatically improve the mechanical properties of polysiloxane by selecting a curing catalyst.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a curable composition capable of producing a thick molded product while utilizing the characteristics of ladder-type polysiloxane, and heat resistance and high elastic modulus using the curable composition. Another object of the present invention is to provide a method for producing a thick molded article.

[0005]

The object of the present invention is to take a titanium-based catalyst among curing catalysts and to combine this titanium-based catalyst with a silsesquioxane ladder polymer. It was achieved by constructing a curable composition in which a hydrophilic crosslinking agent and water or a silica-based crosslinking agent are combined.

That is, the present invention has the following configuration. Formula (1)

[0007]

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(In the formula, R ¹ represents a monovalent hydrocarbon group,
R ² may be the same as or different from each other, R ² represents a monovalent aromatic hydrocarbon group, and may be the same or different from each other, R ³
Represents a hydrogen atom or a monovalent hydrocarbon group, and l, m and n represent 0 or a positive integer satisfying 2 ≦ l + m + n. ) A curable composition comprising a silsesquioxane ladder polymer having a number average molecular weight of 500 or more and a titanium catalyst. Silsesquioxane ladder polymer represented by formula (1), titanium-based catalyst, formula (2)

[0009]

[Chemical 4]

(In the formula, R ⁴ represents a monovalent hydrocarbon group,
k is a positive integer that satisfies 1 ≦ k ≦ 7. C.) A curable composition containing a polyfunctional crosslinking agent represented by the formula (4) and water. A curable composition comprising a silsesquioxane ladder polymer represented by the formula (1), a titanium-based catalyst, and a silica-based crosslinking agent. Curable composition containing the silsesquioxane ladder polymer represented by the above formula (1), a titanium-based catalyst, a polyfunctional crosslinking agent represented by the above formula (2), and a silica-based crosslinking agent . 20 to 200 relative to 100 parts by weight of the silsesquioxane ladder polymer represented by the above formula (1)
The curable composition according to any one of the above 1 to 3 which is uniformly dissolved or dispersed in a volume part of an organic solvent, is kept at a temperature lower than the boiling point of the organic solvent used for 8 hours or more, and then 20 to 400 ° C. Preferably, the method for producing a thick-walled molded product having a thickness of 0.5 mm or more is characterized in that the temperature is raised stepwise or continuously in the range of 20 to 250 ° C.

The present invention will be described in detail below. The silsesquioxane ladder polymer has a structure represented by the formula (1), and its number average molecular weight is 500 or more, preferably 500 to 5000, more preferably 500 to 1500.
Is. In the formula, R ¹ is a monovalent hydrocarbon group, which may be the same or different from each other, and preferably a methyl group.
R ² is a monovalent aromatic hydrocarbon group, which may be the same or different from each other, and is preferably a phenyl group. R ³ is a hydrogen atom or a monovalent hydrocarbon group, preferably a methyl group or an ethyl group. l, m and n are 2 ≦ l + m +
n, preferably 0 or a positive integer satisfying 2 ≦ l + m + n ≦ 12.

In the formula (1), R ¹ and R ² in ¹ repeating unit (hereinafter, this unit is referred to as 1 unit)
May be the same or different for every n units. This means m repeating units (hereinafter this unit is called m unit).
The same applies to R ¹ of R, and the same applies to R ² of n repeating units (hereinafter, this unit is referred to as n unit). Further, the n unit, the m unit, and the l unit may be blocks or may be a random mixture of these.

Next, the titanium-based catalyst used in the present invention is
It is necessary to accelerate the hydrolysis / condensation reaction of the terminal functional group SiOR ³ of the silsesquioxane ladder polymer represented by the formula (1). When a polyfunctional crosslinking agent represented by the formula (2) and water or a silica-based crosslinking agent are used in combination, an alkoxyl group, a silanol group or a silanol group generated by hydrolysis contained in them is used. Condensation reaction, or the terminal functional group SiO of the silsesquioxane ladder polymer represented by the functional group and the formula (1)
It is necessary to accelerate the condensation reaction with R ³ . Titanium-based catalysts that can be used in the present invention include tetraalkyl orthotitanate and titanium chelate. The tetraalkyl ortho titanate is represented by the formula: Ti (OR) ₄ . In the formula, R is a monovalent hydrocarbon group, preferably 1 carbon atom
To 4 monovalent hydrocarbon groups. Examples of such a monovalent hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, and an n-butyl group. Titanium chelate has formula (3)

[0014]

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(Wherein R ⁵ , R ⁷ and R ⁸ represent a monovalent hydrocarbon group, and R ⁶ represents hydrogen or a monovalent hydrocarbon group). Examples of such titanium chelates include diisopropoxybis (ethyl acetoacetate).
Examples thereof include titanium, diisopropoxybis (methylacetoacetate) titanium, diisopropoxybis (acetylacetone) titanium, and dibutoxybis (ethylacetoacetate) titanium, but diisopropoxybis (acetylacetone) titanium is preferably used. The amount of the titanium-based catalyst used is 0.1 to 20 parts by weight, preferably 0.3 to 1 part by weight, relative to 100 parts by weight of the silsesquioxane ladder polymer.
It is 0 part by weight, most preferably 0.5 to 6 parts by weight.
This is because if the amount is less than 0.1 parts by weight, the curing speed is slow, and if the amount exceeds 20 parts by weight, not only the gelation is not carried out uniformly but also the air bubbles remain in the cured product.

The polyfunctional crosslinking agent that can be used in the present invention is represented by the formula (2). In the formula, R ⁴ is a monovalent hydrocarbon group, preferably a methyl group, and k is a positive integer satisfying 1 ≦ k ≦ 7, preferably 4 on average. The amount of the polyfunctional crosslinking agent used is 5 to 50 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the silsesquioxane ladder polymer. This is because if it is less than 5 parts by weight, almost no effect is obtained, and if it exceeds 50 parts by weight, the cured product becomes brittle.

Further, in the present invention, water can be added in order to make the above-mentioned polyfunctional crosslinking agent work sufficiently. The amount of water added is 10 to 60 mol% based on all the alkoxy groups of the polyfunctional crosslinking agent. This is because if it exceeds 60 mol%, a uniform cured product cannot be obtained.

The silica-based cross-linking agent which can be used in the present invention is finely powdered hydrous silica or anhydrous silica. These silanol groups or adsorbed water participate in the condensation reaction of the terminal functional group SiOR ³ of the silsesquioxane ladder polymer represented by the formula (1), and the physical properties of the resulting cured product can be improved. The amount of the silica-based crosslinking agent used is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the silsesquioxane ladder polymer. These silica-based cross-linking agents may be used in combination with the above polyfunctional cross-linking agents.

Furthermore, in the curable composition of the present invention, an organic solvent can be used in order to uniformly mix the above-mentioned respective components. This organic solvent needs to be able to sufficiently dissolve the silsesquioxane ladder polymer and to dissolve water to some extent. As such an organic solvent,
Tetrahydrofuran, 1,4-dioxane, toluene,
Examples include chloroform. The amount of organic solvent used is
2 per 100 g of silsesquioxane ladder polymer
It is 0 to 200 ml, preferably 60 to 120 ml. This is because it is difficult to dissolve the silsesquioxane ladder polymer when the amount is less than 20 ml, and it is difficult to produce a cured product having no bubbles or cracks when the amount exceeds 200 ml.

As described above, the curable composition of the present invention comprises the silsesquioxane ladder polymer, the titanium-based catalyst, the organic solvent, and, if necessary, the polyfunctional crosslinking agent, water, and the silica-based crosslinking agent. It is obtained by mixing at a ratio of.

The method for producing a molded product having a thickness of 0.5 mm or more according to the present invention is as follows:
By controlling the rate of temperature rise, the curing rate due to condensation, the volatilization rate of volatiles from the system, the diffusion rate of volatiles remaining in the system, etc. can be well balanced, and significant cracks are generated in the formed cured product. Without, 0.5m
It was made by discovering that a molded product having a thickness of m or more can be produced. The method for raising the temperature of the curable composition is as follows. First, the temperature is maintained at 20 to 50 ° C., which is lower than the boiling point of the organic solvent used, for 8 hours or more, and then gradually or in the range of 20 to 400 ° C. The temperature is raised continuously. A thick molded body is prepared, for example, by pouring the curable composition into a mold in which a polyimide film is attached with a double-sided tape, placing the lid and allowing it to stand horizontally in a hot-air dryer, and heat curing while gradually raising the temperature. It can be produced by The reason why the polyimide film is stuck is that the cured product has good mold releasability, and even if the cured product contracts during curing, it is easily released from the mold and cracks are less likely to occur. It is preferable that the temperature of the heat curing be raised stepwise or continuously in the range of 20 to 400 ° C. Further, when the temperature is continuously raised, it is preferable to gradually raise the temperature at a rate of 5 ° C./hr or less. Examples of preferable stepwise temperature rising conditions include 50 ° C. for 8 to 24 hours, 80 ° C. for 8 to 24 hours, 100 ° C. for 8 to 24 hours, and 150 ° C. for 12 to 12 hours.
The conditions for heat curing in the order of 70 hours can be mentioned.
In this way, a thick molded body having a high elastic modulus can be manufactured.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples. As the silsesquioxane ladder polymer, a glass resin (trade name) manufactured by Showa Denko KK and having a ratio of substituents on silicon of Me / Ph = 2/1 GR-100 (GP) is used.
The polystyrene standard conversion weight average molecular weight (Mw) and number average molecular weight (Mn) measured by C are Mw / Mn.
= 7210/1260 (same below), Me / Ph = 1
/ 4 GR-908 (Mw / Mn = 1270/680)
Was used. As the polyfunctional crosslinking agent, methyl silicate-51 manufactured by Colcoat Co., Ltd. in which R ⁴ = Me and k = 4 (average) (Me; methyl group) in the formula (2) was used. As the silica-based cross-linking agent, hydrous silica NIPSIL-LP manufactured by Nippon Silica Industry Co., Ltd. was used. The bending test of the obtained cured product was performed according to the method described in JIS K7203 (bending test method using small test pieces). The measurement conditions are: span: 15 mm, indenter: 5R, fulcrum: 2R, test speed: 0.5 mm / min.

(Example 1) Glass resin GR-100 and GR-908 were mixed and the ratio of the substituents on silicon was Me /.
It was prepared so that Ph = 1/1. To 5.0 g of this glass resin mixture was added 5 ml of tetrahydrofuran,
It was completely dissolved using an ultrasonic cleaner. Where Ti
0.15 g of (OBu) ₄ was added and mixed uniformly. Φ 25 μm thick polyimide film attached with double-sided tape
The solution prepared by the above procedure was gently poured into a 6.7 cm ointment can, covered with the lid, and allowed to stand horizontally in a hot air dryer. This is 50 ℃ / 14 hours, 80 ℃ / 22 hours, 1
It was heated and cured in the order of 00 ° C./20 hours and 150 ° C./22 hours. After heat-curing, the side surface of the ointment can was cut open with gold scissors to obtain a light yellow transparent cured product (thickness 0.5 mm). The gel fraction of the cured product was 97%. As a result of the bending test, the bending elastic modulus was 1.91 GPa.

(Example 2) GR-100 was used as the silsesquioxane ladder polymer and a light yellow transparent cured product (thickness 0.5 mm) was obtained by the same procedure as in Example 1. The cured product has a gel fraction of 97% and a flexural modulus of 1.94 GPa.
Met.

Example 3 To 5.0 g of the glass resin mixture used in Example 1, 5 ml of tetrahydrofuran was added and completely dissolved, and further (iso-PrO) ₂ Ti (a) was added.
0.15 g of cac) ₂ (i-Pr; isopropyl, acac; acetylacetonato) was added and mixed uniformly.
The solution prepared by the above procedure was gently poured into a φ6.7 cm ointment can in which a polyimide film having a thickness of 25 μm was adhered with a double-sided tape, and the lid was covered and left still in a hot air dryer so as to be horizontal. This was heated in the order of 50 ° C./24 hours, 80 ° C./24 hours, 100 ° C./24 hours, and 150 ° C./69 hours to be cured. After heat-curing, the side of the ointment can is cut open with gold scissors, and a brown transparent cured product (thickness 0.7 m
m) was obtained. The gel fraction of the cured product was 99%. As a result of the bending test, the bending elastic modulus was 2.11 GPa.

(Example 4) GR-100 was used as the silsesquioxane ladder polymer in the same manner as in Example 3,
50 ° C / 16 hours, 80 ° C / 10 hours, 100 ° C / 13
The coating was heated and cured in the order of 150 ° C./23 hours for 20 hours to obtain a brown transparent cured product (thickness 1.2 mm). The gel fraction of the cured product was 98%, and the flexural modulus was 2.26 GPa.

Example 5 To 5.0 g of the glass resin mixture used in Example 1 was added 5 ml of tetrahydrofuran,
It was completely dissolved using an ultrasonic cleaner. 0.5 g of methyl silicate 51 and (iso-PrO) ₂ T
0.15 g of i (acac) ₂ was added and mixed uniformly. Heat curing was performed in the same procedure as in Example 3 to obtain a brown transparent cured product (thickness 0.9 mm). The gel fraction of the cured product is 9
It was 9%. As a result of a bending test, the bending elastic modulus is 1.94.
It was GPa.

Example 6 Glass Resin GR-100
(5.0 g) and methyl silicate 51 (1.5 g), water (0.10 g), (iso-PrO) ₂ Ti (aca
c) ₂ (0.15 g) in tetrahydrofuran (5 ml)
Was uniformly dissolved in the mixture and heat-cured in the same procedure as in Example 4 to obtain a brown transparent cured product (thickness: 1.4 mm). The gel fraction of the cured product is 98%, and the flexural modulus is 2.19 GPa.
Met.

Example 7 To 5.0 g of the glass resin mixture used in Example 1 was added 5 ml of tetrahydrofuran,
It was completely dissolved using an ultrasonic cleaner. NI
0.5 g of PSIL-LP and (iso-PrO) ₂ Ti
0.15 g of (acac) ₂ was added and mixed uniformly. It was heat-cured by the same procedure as in Example 3 to obtain a brown transparent cured product (thickness 0.5 mm). The gel fraction of the cured product is 99%
Met. As a result of the bending test, the bending elastic modulus is 2.59 GP.
It was a.

Example 8 Glass Resin GR-100
(5.0 g) and NIPSIL-LP (1.0 g), Ti
(OBu) ₄ (Bu; butyl group) (0.15 g) was uniformly dissolved in tetrahydrofuran (5 ml). Pour this into an ointment can with a PI film attached, cover with a lid, and leave at 50 ° C /
14 hours, 80 ° C / 22 hours, 100 ° C / 20 hours, 1
It was heated and cured in the order of 50 ° C./22 hours to obtain a brown translucent cured product (thickness 0.5 mm). The gel fraction of the cured product was 97% and the flexural modulus was 2.28 GPa.

Example 9 Glass Resin GR-100
(5.0 g) was uniformly dissolved in tetrahydrofuran (5 ml), and methyl silicate 51 (1.5 g) was added.
Water (0.10 g), NIPSIL-LP (1.0 g),
Ti (OBu) ₄ (0.15 g) was added and mixed uniformly. Pour this into an ointment can with a PI film attached, cover with a lid, 50 ° C / 14 hours, 80 ° C / 10 hours, 100 ° C / 2
2 hours, heating in order of 150 ℃ / 24 hours to cure,
A brown translucent cured product (thickness 1.5 mm) was obtained. The gel fraction of the cured product was 99%, and the flexural modulus was 2.08 GPa.

Comparative Example 1 Glass Resin GR-100
(5.0 g) was uniformly dissolved in tetrahydrofuran (5 ml), poured into an ointment can similar to that in Example 1, covered with a lid, and mixed with 5
Heat curing was performed in the order of 0 ° C./14 hours, 80 ° C./6 hours, 100 ° C./15 hours, and 150 ° C./12 hours to obtain a cured product (thickness 0.9 mm). Flexural modulus is 1.54 GP
It was a.

(Comparative Example 2) 0.05 g of ammonia water was added as a curing catalyst, and the mixture was heated and cured in the same procedure as in Comparative Example 1 to obtain a cured product (thickness 1.0 mm). The flexural modulus was 1.54 GPa.

[0034]

As described above, the curable composition of the present invention cures the silsesquioxane ladder polymer with a titanium-based curing catalyst, and may contain a polyfunctional crosslinking agent or a silica-based crosslinking agent in some cases. The curable composition is used in combination, and while controlling the temperature and time during heat curing, a thick molded article containing a silsesquioxane ladder polymer as a main component is prepared. As a result, it is possible to obtain a heat-resistant and high-modulus wall-thickness product of a silsesquioxane ladder polymer cured product that can only be used as a coating agent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshifumi Hirose 7-2-3 Kaminomiya, Suma-ku, Hyogo Prefecture

Claims (5)

[Claims] 1. A formula (1): (In the formula, R ¹ represents a monovalent hydrocarbon group, which may be the same or different from each other, R ² represents a monovalent aromatic hydrocarbon group, which may be the same or different from each other, R ³ is hydrogen Represents an atom or a monovalent hydrocarbon group, and l, m, and n are 2 ≦ l + m +
Represents 0 or a positive integer that satisfies n. ) A curable composition comprising a silsesquioxane ladder polymer having a number average molecular weight of 500 or more and a titanium catalyst. 2. A silsesquioxane ladder polymer represented by formula (1), a titanium-based catalyst, and formula (2): (In the formula, R ⁴ represents a monovalent hydrocarbon group, and k is 1 ≦ k ≦
It is a positive integer that satisfies 7. C.) A curable composition containing a polyfunctional crosslinking agent represented by the formula (4) and water. 3. A curable composition containing a silsesquioxane ladder polymer represented by the formula (1), a titanium catalyst, and a silica crosslinking agent. 4. A silsesquioxane ladder polymer represented by the formula (1) according to claim 1, a titanium-based catalyst, and claim 2.
A curable composition comprising a polyfunctional crosslinking agent represented by the formula (2) described above and a silica-based crosslinking agent. 5. 2 parts by weight relative to 100 parts by weight of the silsesquioxane ladder polymer represented by the formula (1) according to claim 1.
The curable composition according to any one of claims 1 to 4, which is uniformly dissolved or dispersed in 0 to 200 parts by volume of an organic solvent, is held at a temperature lower than the boiling point of the organic solvent used for 8 hours or more, Then, a method for producing a thick-walled molded product having a thickness of 0.5 mm or more, which is characterized by heating stepwise or continuously in the range of 20 to 400 ° C.