JPS62148511A - Crosslinking of polyphenylene oxide - Google Patents

Abstract

PURPOSE:To obtain a crosslinked material having improved heat and solvent resistance and physical strength, by subjecting a polyphenylene oxide and a specific silane compound to graft reaction and bringing the resultant polymer into contact with water while in the action of a silanol condensation catalyst. CONSTITUTION:(B) A radical generating agent and (C) a silane compound expressed by the formula RR'SiY2 (R is monofunctional olefinically unsaturated hydrocarbon or monofunctional hydrocarbonoxy containing olefinically unsaturated bond; R' is monofunctional hydrocarbon containing no aliphatic unsaturated bond, H, etc.; Y is hydrolyzable organic group), preferably vinyltrimethoxysilane are added to (A) a polyphenylene oxide and the components (A) and (B) are subjected to grafting reaction in a noncontact state with oxygen. The resultant graft copolymer is then brought into contact and crosslinked with water while in the action of (D) a silanol condensation catalyst, e.g. lead naphthenate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] This invention relates to a method for crosslinking polyphenylene oxide.

[Background technology]

Conventionally, polyester films, polyimide films, etc. have been widely used as film materials for electronic materials.However, polyester films have the disadvantage of not having soldering heat resistance, and polyimide films, although showing good performance, It has the disadvantage of being very expensive.For this reason, it is considered to use crosslinked polyphenylene oxide, which has a relatively high melting point and is relatively inexpensive.

By the way, heretofore, as a reaction of a polymer containing polyphenylene oxide as a main component, for example, JP-A-50-5
As in the method described in Publication No. 1197, a graft copolymer containing no homopolymer of polyphenylene oxide is obtained by reacting a monomer or polymer to be reacted with a radical generator at a temperature higher than the decomposition temperature of the radical generator. There is a way. However, in this method, the branched polymer chains of the graft copolymer have no reactivity, and the crosslinking reaction is not taken into account.

On the other hand, as a crosslinking method using a silane compound, for example, Japanese Patent Publication No. 48-1711, Japanese Patent Application Laid-Open No. 50-2434
2, JP-A No. 51-117549, etc., a method in which a relatively low melting point polymer (for example, an olefin polymer) and a silane compound are kneaded and reacted with an extruder or a hot roll, etc. There is. This method can be easily carried out in the case of relatively low melting point polymers such as olefinic polymers by selecting a radical generator well suited to the kneading temperature. However, in order to apply this method to a polymer with a relatively high melting point such as polyphenylene oxide, there is no radical generator that matches the kneading temperature well, so polyphenylene oxide must be crosslinked using the same crosslinking method as for olefin polymers. It is not possible.

[Purpose of the invention]

This invention was made in view of the above circumstances, and an object of the present invention is to provide a crosslinking method for improving the physical properties such as heat resistance, solvent resistance, and physical strength of relatively inexpensive polyphenylene oxide. .

[Disclosure of the invention]

In order to achieve the above object, the present invention provides polyphenylene oxide with a radical generator and the general formula RR'.
5iYz (R is a monovalent olefinically unsaturated hydrocarbon group or a monovalent hydrocarbonoxy group containing an olefinically unsaturated bond, and R' is a monovalent hydrocarbon group containing no aliphatic unsaturated bond) group, group Y, and hydrogen, and Y is an organic group that can be hydrolyzed), and at a temperature equal to or higher than the decomposition temperature of the radical generator in a state where oxygen does not come into contact with it. The gist of this article is a method for crosslinking polyphenylene oxide, in which the polyphenylene oxide and the silane compound are grafted and the resulting graft polymer is brought into contact with water under the action of a silanol condensation catalyst to effect crosslinking.

The present invention will be explained in detail below.

Here, polyphenylene oxide (also referred to as polyphenylene ether, hereinafter referred to as rPPOJ) is represented by the following general formula, for example, poly(2.
6-dimethyl-1,4-phenylene oxide).

PPOs such as Kono, e.g.
It can be synthesized by the method described in specification 4 of No. 568. For example, 2,6-xylenol is subjected to an oxidative camping reaction with an oxygen-containing gas and methanol in the presence of a catalyst to produce poly(2,6-dimethyl-1,4
-phenylene oxide), but is not limited to this method. Here, the catalyst includes a copper(1) compound, N-N'-di-tert-butylethylenediamine, butyldimethylamine, and hydrogen bromide. Methanol is 2 to 15% by weight based on this
of water is added to the reaction mixture system, and the total of methanol and water is 5
It is used in such a manner that the amount of polymerization solvent becomes ~25% by weight. Although the polyphenylene oxide is not particularly limited, for example, the weight average molecule 1 (Mw) is 50,000,
A polymer with a molecular weight distribution Mw/Mn = 4.2 (Mn is the number average molecular weight) is preferably used. Although PPO may be used alone, it can be used in combination with polystyrene, styrene-butadiene block copolymer, 2-polybutadiene, filling material,
Pigments, etc. are mixed in as a modifier in any proportion to produce PPO.
It may be a resin composition. Polystyrene, styrene-butadiene block copolymer, 1,2-polybutadiene, and the like have the effect of improving the film-forming properties of the resin when formed into a sheet by the casting method described below. Inorganic fillers, for example, improve the dimensional stability of the cured product after crosslinking,
Improve heat resistance, chemical resistance, physical strength, etc.
This has the effect of adjusting the dielectric constant to an appropriate value.

The silane compound has the general formula %formula%() The one expressed as is used.

(A) In the formula, R is a monovalent olefinically unsaturated hydrocarbon group or a monovalent hydrocarbonoxy group containing an olefinically unsaturated bond, such as vinyl, allyl, butenyl, cyclohexenyl, cyclopenta Jenyl, CHz=C(C1h)Coo(CHz) y-5CHz
=C(C113)COOCII□CtlzO(CHz)
:l-3C)Iz=cHcOo (CI□)3-1
Examples include, but are not limited to, the following.

(A) In the formula, R' is either a monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, a group Y, or hydrogen; Examples thereof include, but are not limited to, alkyl such as methyl, ethyl, propyl, tetradecyl, and octadecyl, tolyl such as phenyl and tolyl, and aralkyl such as benzyl.

(A) In formula (A), Y is a hydrolyzable organic group, for example, alkoxy such as methoxy, ethoxy, butoxy, alkoxyalkoxy such as methoxyethoxy, formyloxy, acetoxy.

Acyloxy such as probionoxy, -0N=C(C11□)2. -0N=C(CH3)C2
Oxime groups such as 11S, -0N=C(C611s)z, substituted amino groups [e.g., -NIICIli,
An algylamino group such as -NHCzl15, -Nl! (
arylamino groups such as C611s)], but are not limited to these. Examples of the silane compound include vinyltrimethoxysilane.

Vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriacetylsilane, T-
Methacryloxypropyltrimethoxysilane and the like are preferred, but these are not acceptable.

As the radical generator (initiator), dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne- 3,2,5-dimethyl-2,5-di(tert
-butylperoxy)hexane, α・α′-bis(te
r Peroxide such as t-butylperoxy-m-isopropyl)benzene [also referred to as 1,4 (or 1,3)-bis(tert-butylperoxyisopropyl)benzene] 1 NOF 0 Chrysanthemum bistamyl, etc. was given,
Each can be used alone or in combination of two or more,
Not limited to these.

Silanol condensation catalysts include carboxylic acid salts such as dibutyltin dilaurate, Schif'til diacetate, Schif'til dioctate, stannous acetate, lead naphthenate, zinc caprylate, cobalt naphthenate, titanate esters and Examples include, but are not limited to, organometallic compounds such as chelates. The silanol condensation catalyst is mixed into the reaction system before, during, or after the reaction of PPO and the silane compound. The catalyst is added either as a catalyst or as a precursor to form the catalyst in a subsequent operation.

The raw materials as described above may be mixed in any manner. For example, mixing using a solvent eliminates the need to melt PPO, so it can be easily performed at a relatively low temperature. It is also easy to mix uniformly.

Examples of the solvent include halogenated hydrocarbons such as trichloroethylene, trichloroethane, chloroform, methylene chloride, and carbon tetrachloride, and aromatic hydrocarbons such as chlorobenzene, benzene, toluene, xylene, and ethylbenzene, each used singly or in combination. Although the above-mentioned mixtures can be used, the present invention is not limited thereto.

The blending ratio is not particularly limited, but ppoi.

0 parts by weight, 0.1 to 10 parts by weight of the silane compound, 0.05 to 5 parts by weight of the radical generator, and 0.02 to 0.5 parts by weight (more preferably 0.0 parts by weight) of the silanol condensation catalyst.
0.05 to 0.5 parts by weight).

Although not particularly limited, the concentration of the solution when dissolved in a solvent is 20 to 30% when the solvent is a halogenated hydrocarbon;
When the solvent is an aromatic hydrocarbon, it is preferably 40 to 50%.

This is due to the solubility of PPO in the solvent, and as a guide, the solution viscosity near the boiling point of the solvent used is 50.
It is desirable that it be about 00 cP or less.

Specific operations are performed, for example, by the following procedure, but are not limited thereto. First, a certain amount of solvent and PPO are placed in a container equipped with a device capable of uniform stirring, and the mixture is thoroughly heated and stirred until uniform. After that, release the oxygen inside the container. For example, there are methods such as reducing the pressure, evacuation, and replacing with an inert gas such as nitrogen gas, and although nitrogen replacement is preferable, the method is not limited to these methods. If the method of this invention is carried out under an inert gas atmosphere from the beginning, there is no particular need to expel oxygen. If oxygen exists in the reaction system between PPO and the silane compound, the grafting reaction will be inhibited, and the crosslinking reaction will be inhibited, so oxygen is removed to prevent oxygen from coming into contact with each other. Note that the state where oxygen does not come into contact with oxygen means not only the case where there is no contact at all in a strict sense (but also includes the case where there is some contact with oxygen).

After the oxygen in the container is sufficiently exhausted, add the silane compound and radical generator without stirring. In this case, it is preferable to add it gradually, such as by dropping it. At this time, the silane compound and the radical generator may be mixed immediately before addition, or may be added separately by dropping them separately. When dropping, the dropping speed is not particularly limited. As the radical generator, it is preferable to use one whose decomposition temperature is near the boiling point of the solvent used, and it is not so preferable to use one whose boiling point and decomposition temperature are significantly different.

In this way, the graft reaction is carried out at a temperature higher than the decomposition temperature of the radical generator and with stirring near the boiling point of the solvent. The reaction time is preferably about twice the decomposition time of the radical generator at that temperature, and is generally 2 to 3 hours. After sufficient reaction, stop heating by removing the heating device, lower the temperature of the liquid to around room temperature without stirring, add the silanol condensation catalyst, and stir until the mixture becomes uniform. After stirring until the solution is homogeneous (this solution is
(referred to as solution B), the solvent is removed by an appropriate method.

In this case, it is preferable to use solution B to produce the sheet, since this graft polymer has improved film-forming properties compared to the case of PPO alone. That is, a graft polymer sheet can be obtained by a method (casting method) in which Solution B is cast or coated onto an appropriate material to form a thin layer and then dried to remove the solvent. When formed into a sheet in this manner, the solvent can be easily removed and subsequent processing is also easy.

To describe the casting method in detail, the solution B is made into a thin layer on a mirror-treated iron plate or a carrier film for casting, and then
Casting to a thickness of 700 (preferably 5 to 500) μm (
Alternatively, a sheet is obtained by coating (or coating) and thoroughly drying to remove the solvent. Note that the term "sheet" here includes what is called a film, membrane, tape, etc., and there are no particular limitations on the extent of the surface orthogonal to the thickness direction or the length, and the thickness can also be set in various ways depending on the application. It is possible to do so. The carrier film for casting is not particularly limited, but may include polyethylene terephthalate (hereinafter referred to as rPF).
(abbreviated as TJ) film, polyethylene film, polypropylene film, polyester film, polyimide film, etc. are preferably insoluble in the above solvents, and
Those that have been subjected to mold release treatment are preferable. The solvent is removed from the solution B cast (or applied) onto the carrier film for casting by air drying and/or drying with hot air. The upper limit of the set temperature during drying is preferably lower than the boiling point of the solvent or lower than the heat-resistant temperature of the carrier film for casting (when drying is performed on a gear carrier film for casting),
The lower limit is determined by drying time, processability, etc. For example, when trichlorethylene is used as a solvent and PET film is used as a carrier film for casting, a range from room temperature to 80°C is preferable, and the temperature should be kept within this range. If the temperature is increased, the drying time can be shortened.

In addition, the solution B may be impregnated into a base material and then the solvent may be removed. Such a material is hereinafter referred to as prepreg. This prepreg may be made by any method, but generally it can be made by the following method.

That is, by dipping the base material in solution B, the graft polymer is impregnated and adhered to the base material. After this, the solvent is removed by drying or the like. Base materials include glass cloth, aramid cloth, polyester cloth,
Examples of materials that can be used include, but are not limited to, resin-impregnated materials such as nylon cloth, mat-like materials and/or fibrous materials such as non-woven fabric made of these materials, kraft paper, linter paper, and the like.

The graft polymer in any shape such as a sheet or prepreg produced as described above is brought into contact with water in boiling water, cold water, steam, etc. under the action of the silanol condensation catalyst to cause a crosslinking reaction. Although this crosslinking reaction proceeds in the presence of water, it is preferably carried out in boiling water in order to shorten the reaction time.

The polyphenylene oxide crosslinked by the method of the present invention, such as sheets and prepregs produced in this way, has good heat resistance, chemical resistance, and physical strength. It is also inexpensive. Therefore, according to the method of the present invention, a crosslinked PPO sheet or prepreg having heat resistance, solvent resistance, and physical strength optimal for electronic material applications can be obtained.

It should be noted that the grafted polymer can be stored in a substantially unchanged form for a considerable period of time if kept out of contact with water.

Examples and comparative examples are shown below.

(Example 1) 2 with connected cooling pipe, nitrogen blowing pipe and dropping funnel
600 g of xylene in a 000 ml three-bottle flask,
400 g of polyphenylene oxide was added, heated to 150° C. with an oil path, and stirred for about 1 hour to completely dissolve. Next, add vinyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd. (horizontal KBM-1003 > 8 g, Jeter) to the dropping funnel.
After adding 8 g of t-butyl peroxide and completely purging the inside of the flask with nitrogen, the entire flask was added dropwise over about 10 minutes.

Thereafter, the mixture was stirred for an additional 2 hours while keeping the temperature and stirring conditions constant. After 2 hours, the oil bath was removed and cooled with water instead to lower the liquid temperature to 30°C or less. However, stirring was continued even during cooling. While further stirring, 0.08 g of dibutyltin dilaurate was added dropwise, and the mixture was stirred for about 30 minutes. This solution was spread onto a 75 μm PET film with a thickness of 250 μm.
It was applied thickly and dried at 70°C for 10 minutes. The sheet (film) thus made is peeled off from the PET film,
Further, the sheet was dried at 155° C. for 30 minutes to obtain a sheet having a thickness of about 100 μm. This sheet was immersed in boiling water for about 8 hours to cause a crosslinking reaction, thereby obtaining a crosslinked sheet.

The physical properties of this crosslinked sheet are shown in Table 1.

(Example 2) A crosslinked sheet was obtained in exactly the same manner as in Example 1, except that vinyltriethoxysilane was used instead of vinyltrimethoxysilane. The physical properties of this crosslinked sheet are shown in Table 1.

(Example 3) A crosslinked sheet was obtained in exactly the same manner as in Example 1, except that dicumyl peroxide was used instead of di-tert-butyl peroxide. The physical properties of this crosslinked sheet are
Shown in the table.

(Example 4) Except that vinyltriethoxysilane was used instead of vinyltrimethoxysilane and dicumyl peroxide was used instead of di-tert-butyl peroxide.
A crosslinked sheet was obtained in exactly the same manner as in Example 1. The physical properties of this crosslinked sheet are shown in Table 1.

(Example 5) A crosslinked sheet was obtained in exactly the same manner as in Example 1, except that ethylhenzene was used instead of xylene. The physical properties of this crosslinked sheet are shown in Table 1.

(Comparative Example) 600 g of xylene and 400 g of polyphenylene oxide were placed in a 2,000-meter/3-hole flask connected to a cooling tube, heated to 150° C. in an oil bath, and stirred for about 1 hour to completely dissolve them. After cooling this solution to 30°C or lower without adding a radical generator or a silane compound, the solution was heated to 75°C.
Coated to a thickness of 250 μm on a PET film of 7 μm.
After drying at 0°C for 10 minutes, the resulting sheet was peeled from the PET film and dried at 155°C for an additional 30 minutes.

The physical properties of this sheet are shown in Table 1.

Among the physical properties of each sheet, the gel fraction was determined by immersing each sheet in trichloroethylene resin (Toa Gosei Kagaku Kogyo Co., Ltd.'s Trichlene) for 24 hours and observing the weight change. The higher the gel fraction, the better. Table 1 also shows the raw material composition of each sheet and the solvent used.

As shown in Table 1, each sheet obtained in Examples 1 to 5 had a better film shape, better physical strength, and higher gel fraction than the uncrosslinked sheet obtained in the comparative example. , soldering heat resistance is also good. The film formability of the graft polymers in Examples 1 to 5 was also better than that of the comparative example.

It can be seen that PPO crosslinked by the method according to the present invention exhibits good heat resistance, chemical resistance, and physical strength.

〔Effect of the invention〕

As described above, the method for crosslinking polyphenylene oxide according to the present invention involves grafting polyphenylene oxide and the above-mentioned silane compound, and contacting the resulting graft polymer with water under the action of a silanol condensation catalyst to crosslink the polyphenylene oxide. The resulting crosslinked polyphenylene oxide has good heat resistance, chemical resistance, and mechanical strength.

Claims (5)

[Claims] (1) Polyphenylene oxide, a radical generator and the general formula RR'SiY_2 (R is a monovalent olefinically unsaturated hydrocarbon group or a monovalent hydrocarbonoxy group containing an olefinically unsaturated bond, R' is either a monovalent hydrocarbon group containing no aliphatic unsaturated bond, a group Y, or hydrogen, and Y is a hydrolyzable organic group), and a silane compound represented by A polyphenylene in which the polyphenylene oxide and the silane compound are subjected to a graft reaction at a temperature higher than the decomposition temperature of the radical generator in a non-contact state, and the resulting graft polymer is brought into contact with water under the action of a silanol condensation catalyst to effect crosslinking. Oxide crosslinking method. (2) The method for crosslinking polyphenylene oxide according to claim 1, wherein a radical generator and a silane compound are added after the polyphenylene oxide is dissolved in a solvent. (3) The method for crosslinking polyphenylene oxide according to claim 2, wherein the grafting reaction is carried out in a solvent. (4) The method for crosslinking polyphenylene oxide according to claim 3, wherein the graft polymer is formed into a sheet by a casting method. (5) The silane compound is vinyltrimethoxylane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriacetylsilane, and
The method for crosslinking polyphenylene oxide according to any one of claims 1 to 4, wherein the polyphenylene oxide is at least one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane.