JP2016014094A - Polybenzoxazine-silica composite and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polybenzoxazine-silica composite which further improves heat resistance of a polybenzoxazine resin and further has excellent transparency.SOLUTION: There is provided a polybenzoxazine-silica composite having excellent heat resistance and transparency which is obtained by polymerizing a benzoxazine compound by subjecting a resin composition comprising a benzoxazine compound (A), perhydropolysilazane (B) and a solvent (C) for dissolving perhydropolysilazane to heat treatment and converting perhydropolysilazane to silica.

Description

  The present invention relates to a resin composition containing a benzoxazine compound, a perhydropolysilazane and a solvent for dissolving perhydropolysilazane, a polybenzoxazine-silica composite obtained by heat-treating the resin composition, and a polybenzoxazine- The present invention relates to a method for producing a silica composite.

Polyoxazine resins obtained by ring-opening polymerization of benzoxazine compounds with heat are excellent in flame retardancy, dimensional stability, low water absorption, low dielectric constant, and heat resistance, and generate by-products during the polymerization process and molding process. Therefore, it is a resin capable of various molecular designs that can obtain a void-free resin with good dimensional stability. Among them, high heat resistance is particularly noted, but the glass transition temperature is not so high as about 160 ° C., and higher heat resistance is required. In recent years, there is an increasing need for high heat-resistant resins in the fields of electronics such as semiconductors and liquid crystals, as well as structural materials in the fields of space, aviation, and automobiles. Especially for semiconductor encapsulants and laminated substrates, heat resistance is required, and for SiC power semiconductors, etc., the glass transition temperature is 250 ° C or higher. Sexuality has been demanded. In the electronics field, there is a demand for low water absorption as well as high heat resistance of 300 ° C. or higher that can withstand lead-free flow soldering. Patent Document 1 reports that inclusion of a silane compound having a siloxane skeleton and an imide bond improves the glass transition temperature (Tg) and increases the thermal decomposition temperature. However, a silane compound having a siloxane skeleton and an imide bond described in Patent Document 1 is not easy to synthesize, which causes an increase in cost.
It has also been reported that heat resistance is improved by mixing fine particles with polybenzoxazine resin (Patent Document 2). However, it is not known to function as nanoparticles by chemical bonding.

JP 2013-185056 A JP 2013-166853 A

  An object of the present invention is to provide a polybenzoxazine-silica composite that further enhances the heat resistance of the polybenzoxazine resin and is excellent in transparency.

  The inventors have excellent heat resistance by heat-treating and curing a resin composition containing a benzoxazine compound (A), perhydropolysilazane (B), and a solvent (C) that dissolves perhydropolysilazane. The present inventors have found that a polybenzoxazine-silica composite can be obtained and have completed the present invention.

  That is, this invention relates to the resin composition containing the solvent (C) which melt | dissolves a benzoxazine compound (A), perhydropolysilazane (B), and perhydropolysilazane (B).

  The present invention also relates to the above resin composition, wherein the content of perhydropolysilazane (B) is 0.5 to 50 parts by weight with respect to 100 parts by weight of the benzoxazine compound (A).

  Moreover, this invention relates to the polybenzoxazine-silica composite obtained by heat-processing the said resin composition.

  Furthermore, the present invention includes a step of preparing a resin composition by mixing a benzoxazine compound (A), perhydropolysilazane (B), and a solvent (C) that dissolves perhydropolysilazane under an inert atmosphere; The present invention relates to a method for producing a polybenzoxazine-silica composite, which comprises a step of polymerizing a benzoxazine compound and converting perhydropolysilazane to silica by heat-treating a resin composition.

The polybenzoxazine-silica composite of the present invention is more excellent in heat resistance than the polybenzoxazine resin alone, and further excellent in transparency.
That is, it can be seen from TG-DTA that when the polybenzoxazine resin alone is heated, the mass is suddenly reduced from a temperature exceeding about 400 ° C. (see FIG. 5). On the other hand, since the polybenzoxazine-silica composite of the present invention, which is a nanocomposite of a polybenzoxazine resin and silica, can suppress weight loss, it is excellent in performance as a high heat resistant resin.
Further, according to observation with a TEM, silica is dispersed on a nanoscale, and therefore, there is little influence on resin physical properties such as strength reduction of the composite itself. Furthermore, since polybenzoxazine and silica are chemically bonded, they also function as an impact fracture progress suppressing material.

It is a FT-IR spectrum figure of PBz-PHPS3. It is a FT-IR spectrum figure of PBz-PHPS4. It is a FT-IR spectrum figure of PBz-PHPS5. It is a FT-IR spectrum figure of PBz and PBz-PHPS1-5. It is a figure which shows the measurement result by TGA of PBz and PBz-PHPS1-5. It is a figure which shows the measurement result by TGA of PBz-PHPS5 and PBz-PHPS5a. 6 is a NMR spectrum diagram of B-hda obtained in Example 6. FIG. 6 is a view showing the appearance of a composite obtained in Example 6. FIG. FIG. 6 is a view showing the transparency of the composite obtained in Example 6.

  Hereinafter, the present invention will be described in detail.

  The resin composition of the present invention contains a benzoxazine compound (A), perhydropolysilazane (B), and a solvent (C) that dissolves perhydropolysilazane (B).

  The benzoxazine compound used in the present invention is preferably a compound represented by the following general formula (1) or an oxazine oligomer represented by the following general formula (2).

  In the formulas (1) and (2), X is a divalent group selected from (a) to (f) shown in the following general formula (3), and the formula (c) is particularly preferable. R independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group, and is preferably a phenyl group. Moreover, in Formula (2), m is 1-10, Preferably it is 2-8, n is 2-30.

  Compared with the benzoxazine compound of the general formula (1), the oxazine oligomer of the general formula (2) can form a film having excellent film forming properties.

The perhydropolysilazane used in the present invention is an inorganic polymer soluble in an organic solvent having —SiH ₂ —NH— as a basic unit. In the following specification, perhydropolysilazane is described as polysilazane or PHPS.
The polysilazane used in the present invention preferably has a molecular weight of 400 to 2000, more preferably 600 to 1000. Two or more types may be mixed and used.

  The blending ratio of the benzoxazine compound (A) and the polysilazane (B) is preferably 0.5 parts by weight or more of polysilazane (B) with respect to 100 parts by weight of the benzoxazine compound (A). More preferred is 3 parts by weight or more. Further, it is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, further preferably 30 parts by weight or less, and most preferably 20 parts by weight or less. If the amount is less than 0.5 parts by weight, the effect of improving heat resistance is small, and if it exceeds 50 parts by weight, the transparency of the composite is lost.

The resin composition of the present invention contains a solvent (C) that dissolves polysilazane (B).
The solvent (C) is not particularly limited as long as it does not have a hydroxyl group, but is aromatic such as benzene, toluene, xylene, mesitylene, methoxybenzene, tetrahydrfuran (THF), dioxane, diethyl ether, Ethers such as dibutyl ether, dimethoxyethane, diethoxyethane, glycol ethers, glycol esters, esters, ketones, halogens, dimethylformamide (DMF), dimethylacetamide (DMA), dimethylsulfoxide (DMSO), etc. Among these, THF is particularly preferable.
The solvent (C) is preferably a solvent that also dissolves the benzoxazine compound (A).

The resin composition of the present invention is prepared by mixing the benzoxazine compound (A), the polysilazane (B), and the solvent (C) under an inert atmosphere.
The mixing method is not particularly limited, but a solution in which polysilazane (B) is dissolved in a solvent (C) is prepared in an inert atmosphere, and this solution and the benzoxazine compound (A) are placed in an inert atmosphere. The method of mixing is mentioned.
As a preferred method for preparing the resin composition, a benzoxazine compound solution and a polysilazane solution are respectively prepared using a solvent that dissolves both the benzoxazine compound (A) and the polysilazane (B), and the solutions are mixed. Is mentioned. At this time, the solvent used for the benzoxazine compound (A) and the solvent used for the polysilazane (B) may be the same or different, but are preferably the same solvent. When different solvents are used, it is preferable that these solvents are mixed well.
The concentration of the solution is not particularly limited, but it is not preferable if it is too dilute or too thick, and is usually adjusted within a range where the amount of the solvent in the resin composition is 2 to 1000 times.
Moreover, as a mixing method of the solution, a method of dropping one solution into the other solution while stirring can be mentioned, for example, a method of dropping a polysilazane solution into a benzoxazine compound solution, or a benzoxazine compound solution into a polysilazane solution. The method of dripping may be used. Although there is no restriction | limiting in particular about dropping speed, 0.1-10 mL / min is preferable.

In the present invention, a polybenzoxazine-silica composite is formed by curing the above resin composition by heat treatment.
That is, by heat-treating the resin composition under predetermined conditions, the benzoxazine compound is subjected to ring-opening polymerization, and polysilazane is converted to silica, so that a polybenzoxazine-silica composite in which polybenzoxazine and silica are chemically bonded. You can get a body.

The heat treatment is finally performed at a temperature of 180 ° C. to 350 ° C., preferably 240 ° C. to 300 ° C. Examples of the heat treatment operation include a method in which the temperature is raised from room temperature to about 70 ° C. to the target temperature continuously or stepwise. The heat treatment time is not particularly limited as long as it is a time sufficient to obtain the target polybenzoxazine-silica composite. Usually 0.5 to 100 hours, preferably 1 to 24 hours.
The rate of temperature increase in the case of continuous temperature increase is usually 0.01 to 10 ° C./min, preferably 0.1 to 3 ° C./min.
When the temperature is raised stepwise, for example, at room temperature to 70 ° C. for several hours (for example, 0.5 to 10 hours, preferably 1 to 5 hours, the same shall apply hereinafter), and thereafter, for example, within a range of 100 ° C. to 300 ° C. A mode in which heat treatment is performed by holding at several appropriate temperatures for several hours, respectively.
Note that it is not preferable for a thin film of 50 μm or less to suddenly start the reaction from a high temperature such as 180 ° C. to 200 ° C. because it reacts rapidly and foaming occurs due to desorption of ammonia or the like.
The heat treatment is not particularly limited in an air atmosphere or an inert atmosphere, but is preferably performed in an inert atmosphere from the viewpoint of avoiding the influence of moisture in the air.

  As an aspect of forming a polybenzoxazine-silica composite by heat treatment, for example, a solution of a resin composition containing a benzoxazine compound (A) and a polysilazane (B) was subjected to surface hydrophobization treatment in a glove box. There is a method in which the glass plate is cast on a glass plate, left standing and dried to prevent generation of bubbles due to ammonia gas, and then heated using a hot plate.

The benzoxazine compound undergoes ring-opening polymerization by heat treatment as follows. Note that R in formula formula (2) in the - _{(CH 2) m} - is that of.

Then, the OH group formed by ring-opening polymerization and polysilazane react and chemically bond with each other through a C—O—Si bond. In addition, polysilazane is converted to silica by heating to form the polybenzoxazine-silica composite of the present invention.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
In the following, PBz represents polybenzoxazine, and PBz-PHPS represents a polybenzoxazine-silica composite.

(Examples 1-5, Comparative Example 1)
A predetermined amount of N, N-120 (manufactured by AZ electronic materials, PHPS 20 wt% dibutyl ether solution) was dried at room temperature under reduced pressure. A THF solution (solution A) of benzoxazine monomer (abbreviated as Ba monomer) and a solution B in which dried PHPS was dissolved in THF were prepared. Solution B was prepared under a nitrogen atmosphere.
In a nitrogen atmosphere, the solution B was added dropwise to the solution A while stirring (dropping rate 0.05 mL / 3 seconds), and then stirred for 1 hour to obtain a coating solution. The coating solution was cast on a glass plate that had been surface-hydrophobized in the glove box, left in the glove box for 1 hour, and dried (to prevent the generation of bubbles due to ammonia gas). Next, the coated glass plate is heated in an air atmosphere at 70 ° C. for 5 hours, 100 ° C. for 5 hours, 150 ° C. for 2 hours, 200 ° C. for 2 hours, and 240 ° C. for 2 hours. It was. The amount charged is shown in Table 1.

The analysis was based on the following.
(1) FT-IR (Jasco FT-IR4100ST)
Sampling was performed at each reaction time, and ATR method (ZnSe prism) was used to perform ATR correction. Resolution: 2.0 cm ⁻¹ , totaling 80 times.
(2) TGA
Using a thermogravimetric measuring device (Shimatsu, TGA-50), measurement was performed at 25 to 900 ° C. under a nitrogen atmosphere at a heating rate of 10 ° C./min.
(3) DSC
Using a differential scanning calorimeter (Shimazu, DSC-60), the temperature was measured up to 350 ° C. at a heating rate of 5 ° C./min in a nitrogen atmosphere.

(4) Progress of reaction The progress of the reaction was measured by FT-IR. The measurement results of PBz-PHPS3, PBz-PHPS4, and PBz-PHPS5 are shown in FIG. 1, FIG. 2, and FIG. 3, respectively.
The attribution of peaks in the figure is as follows.
Si-H: 2100 cm < ^-1 >, Si-O: 1080 cm < ^-1 >, Si-N: 840 cm < ^-1 >
· 930 cm ^-1 and 1505cm ^-1 peak reduction of: increasing the opening · 1080 cm ^-1 peak of benzoxazine ring: Si-O-Si confirmation bonds · 1480 cm ^-1 peak increases of: Checking ring-opening polymerization · 1635 cm ^{- 1} peak increase: confirmation of OH group of phenol bonded with hydrogen ・ 3400 cm ⁻¹ increase of peak: confirmation of OH group formation

It can be seen from FIGS. 1 to 3 that the ring opening of the polymer, the conversion of PHPS, and the reaction between the polymer and PHPS occur competitively. Since no Si—H or Si—O peaks are observed, it is considered that PHPS was converted to silica in the early stage of heating. In PBz-PHPS4, the silica peak becomes clear from 150 ° C., and increases as the reaction temperature increases. On the other hand, it is considered that the monomer is ring-opened at 150 ° C. to generate OH groups, completely ring-opened at 240 ° C., and some OH groups that have not reacted with SiO ₂ remain.

Next, FIG. 4 shows the composite (PBz-PHPS 1 to 5) at 240 ° C. and the FT-IR of the PBz polymer.
In FIG. 4, a to f are PBz, PBz-PHPS5, PBz-PHPS4, PBz-PHPS3, PBz-PHPS2 and PBz-PHPS1, respectively.
According to FIG. 4, since the peak of the OH group at 3400 cm ⁻¹ is not as large as that of the polymer, it is considered that OH of the phenyl group and silazane are chemically bonded to form C—O—Si bonds. In the case of the PBz-PHPS1 composite, the amount of silica is large and the particles tend to aggregate, so it is considered that the OH group peak is larger than that of the polymer.

The measurement result by TGA is shown in FIG.
From the results shown in FIG. 5, it can be seen that PBz rapidly loses weight when it exceeds 400 ° C., but the composite of the present invention has less weight loss than PBz, and in particular, PBz-PHPS1 has a smaller weight reduction degree. .

About PBz-PHPS5, when reaction start temperature was 200 degreeC and it was made to react to 240 degreeC, it foamed rapidly immediately after putting on a hotplate. Let the obtained composite be PBz-PHPS5a.
The measurement result by TGA of PBz-PHPS5 and PBz-PHPS5a is shown in FIG. FIG. 6 shows that the heat resistance of PBz-PHPS5a is lower than that of PBz-PHPS5. Therefore, from the viewpoint of heat resistance, stepwise heating is preferable for the synthesis in this system.

(Example 6)
High molecular weight benzoxazine (B-hda) was synthesized as follows.
Hexamethylenediamine (0.01 mol, 1.16 g), bisphenol A (0.01 mol, 2.28 g), and paraformaldehyde (0.04 mol, 1.20 g) were added to 50 mL of chloroform, and refluxed for 5 hours. . The colorless and transparent reaction solution was dissolved in 450 mL of chloroform, washed twice with 0.5 N NaHCO ₃ aqueous solution and 3 times with distilled water using a 1000 mL separatory funnel, and dehydrated with anhydrous sodium sulfate for 1 day. The solution was concentrated with an evaporator and dried under reduced pressure for 1 day to obtain 3.43 g (yield: 88%) of light yellow high molecular weight benzoxazine (B-hda).

The NMR spectrum of the obtained B-hda is shown in FIG.
The structure determined from NMR is as follows.
That is, B-had is a mixture of a polymer having NH ₂ groups at both ends and a polymer having one OH group and one NH ₂ group bonded to both ends, and x = 11.15 and y = 11.15. X + y = 22.3 and Mw = 8029.

A complex was synthesized using the B-hda obtained above.
The amounts of B-had and PHPS charged are shown in Table 2. The solvent amount of the resin composition is 10 ml of THF.
The heat treatment was performed in an air atmosphere at 50 ° C. for 5 hours, 100 ° C. for 1 hour, 120 ° C. for 1 hour, 160 ° C. for 1 hour, 200 ° C. for 1 hour, and 240 ° C. for 1 hour.
The film forming property was improved by using the oligomer.
The appearance (effect of heating temperature) of the composite is shown in FIG. 8, and the transparency (UV-Vis measurement) is shown in FIG. 8 and 9, a is a composite when held at 50 ° C for 5 hours, b is a composite when further held at 100 ° C for 1 hour, and c is further held at 120 ° C for 1 hour. And d is a composite when further maintained at 160 ° C. for 1 hour, e is a composite when further maintained at 200 ° C. for 1 hour, and f is a composite when further maintained at 240 ° C. for 1 hour. Is the body.

Claims (4)

  A resin composition comprising a benzoxazine compound (A), perhydropolysilazane (B), and a solvent (C) that dissolves perhydropolysilazane.   The resin composition according to claim 1, wherein the content ratio of perhydropolysilazane (B) to 100 parts by weight of the benzoxazine compound (A) is 0.5 to 50 parts by weight.   A polybenzoxazine-silica composite obtained by heat-treating the resin composition according to claim 1.   A step of preparing a resin composition by mixing a benzoxazine compound (A), perhydropolysilazane (B), and a solvent (C) for dissolving perhydropolysilazane under an inert atmosphere, and heat-treating the resin composition And a step of polymerizing a benzoxazine compound and converting perhydropolysilazane to silica. A method for producing a polybenzoxazine-silica composite, comprising: