JPS5843411B2 - Seizouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thermosetting resin that exhibits no tackiness at room temperature and is suitable for producing prepregs free of flowaking.

Recently, attempts have been made to apply polybutadiene to various uses because it has excellent heat resistance and electrical properties and is relatively inexpensive.

For example, attempts have been made to subject a terminal glycol 2 polybutadiene having pendant double bonds to a chain extension reaction using a diisocyanate, and to cure it using a radical polymerization initiator.

The cured product of this product has excellent chemical stability, electrical insulation, water resistance, and processability, and is also recognized to have excellent mechanical and thermal properties. The former has a good affinity for hydrocarbon solvents, but has the disadvantage that it remains sticky even when impregnated into various base materials and dried, making it extremely difficult and impractical to form into laminated or molded materials. .

In other words, the prepreg impregnated into a glass fiber base material and heated to a B-stage (semi-cured) state is sticky and not tack-free, so if stored in layers in that state, each of the above prepregs will adhere, so
In order to store them in an overlapping manner, it is necessary to use spacers, which is currently extremely difficult in terms of workability.

As a result of intensive research to solve the above drawbacks, the present inventors reacted 1,2 polybutadiene glycol with diisocyanate to obtain a prepolymer having an incyanato group at the end, and then added the incyanato group to the prepolymer. In tetracarboxylic acid, Ar represents an aromatic nucleus or a derivative thereof), which is reacted with an acid anhydride, and then a radical polymerization initiator is added. The present inventors have completed the present invention by discovering that the cured product thereof has particularly excellent heat resistance, as well as mechanical, electrical, and chemical properties.

Each component used in the present invention will be explained below.

The 1,2 polybutadiene glycol used in the present invention is represented by the following structural formula.

(In the formula, n is 5≦n≦100.

) Also, the diisocyanates used in the present invention are aliphatic, aromatic and heterocyclic diisocyanates, such as ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, Cyclohexylene 4-isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, diphenylmethane-4,4'-diisocyanate, diphenyl ether-4,4/-diisocyanate , 1-chlorobenzene-2.4' diisocyanate.

It is also possible to use diisocyanates whose inocyanate groups are masked with a compound having active hydrogen such as phenol.

When carrying out the present invention, first, the 1,2-polybutadiene glycol is placed in a reaction vessel, dissolved in an organic solvent, and then diisocyanates are gradually added to perform a polyaddition reaction to form terminal isocyanate precipitates. We obtain polymers.

In this case, a suitable catalyst (triethylenediamine,
tertiary amines or organometallic compounds such as triethylamine, N-ethylmorpholine, tin oleate, dibutyltin laurate, stannous octylate, and lead naphthenate).

The catalyst is suitably added in an amount of 0.01 to 0.5% by weight based on the resin content of the reaction system.

Of course, these catalysts can be used alone, but there is no problem in using two or more of them in combination.

Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, and methyl-n-propyl ketone;
Polar solvents such as N-dimethylformamide, N-methylpyrrolidone, and hexamethylphosphoramide are used, but in consideration of the workability of the resulting thermosetting resin, low-boiling point ketone solvents or ketone solvents and benzene are used. A mixed solvent with a hydrocarbon solvent such as toluene or xylene is preferably used.

In obtaining the above-mentioned terminal isocyanate prepolymer, the molar ratio of 1.2 polybutadiene glycol and diisocyanate is used in the range of 1:1.2 to 2.2,
Preferably, the ratio is 1:1.8 to 2.

The above molar ratio is determined because the object of the present invention is to obtain a thermosetting resin that is solid at room temperature and has no tackiness.

Further, the reaction temperature is suitably 60 to 80°C, and the reaction time is suitably about 3 to 5 hours.

However, it is clear that the above conditions vary depending on the type of diisocyanate and are not strictly limited.

Then, in the solution of the terminal isocyanate prepolymer obtained as described above, an equivalent amount or a nearby amount of tetracarboxylic dianhydride aromatic core or a derivative thereof is added.)
A thermosetting resin can be obtained by adding an acid anhydride and carrying out a polycondensation reaction.

Here, as the tetracarboxylic dianhydride, 2, 3, 6
・7 Naphthalenetetracarboxylic dianhydride, 3.3′・
4,4' diphenyltetracarboxylic dianhydride, benzene 2,4,5 tetracarboxylic dianhydride, butane-1
・2,3,4-tetracarboxylic dianhydride, etc.
can be given.

The above polycondensation reaction conditions are 60 to 110° in the above solvent.
A range of C110 to 20 hours is suitable.

Further, in this polycondensation reaction, the above catalyst can be used as it is.

Since these reaction conditions vary depending on the composition of the reaction system, the type of catalyst, etc., it is desirable to determine them accordingly.

The thermosetting resin solution obtained in the above manner is a yellowish brown, transparent and viscous solution, and by adding a radical polymerization initiator to this, a varnish with freely adjustable pot life can be obtained. .

Examples of the radical polymerization initiator to be added to the thermosetting resin solution include organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, t-
Examples include butyl perbenzoate, di-t-butyl-benzoate, cumene hydroperoxide, dicumyl peroxide, and examples of azo compounds include azobisisobutyronitrile.

Further, the blending amount thereof is used in the range of 1 to 5% by weight based on the amount of resin.

In addition, calcium carbonate, clay, talc,
Fillers such as silica, aluminum oxide, antimony dioxide, reinforcing agents such as glass, mica, etc. can be added.

By impregnating a base material with the thermosetting resin solution obtained as described above and then removing the solvent by heating, a dry prepreg with no tackiness can be obtained.

As the base material, for example, base materials such as glass fiber, glass mat, asbestos paper, synthetic fiber cloth, synthetic fiber mat, inorganic or organic paper can be used.

A laminate is obtained by stacking the prepregs thus obtained and press-molding them.

When molding, the temperature is 150°C to 180°C and the molding pressure is 5.
Molding conditions of 0 to 200 kg/cni and a molding time of 30 to 90 minutes are used.

As is clear from the above, the thermosetting resin obtained by the present invention shows no tackiness at room temperature, can form a prepreg without blocking, and has good storage and workability. It will be done.

Furthermore, the laminate obtained by pressure molding the prepreg has excellent mechanical, electrical, and chemical properties, and particularly has excellent heat resistance.

Examples will be described below.

Example 1 1.2-Polybutadiene glycol (N15so-PBG-1 manufactured by Nippon Soda, Ltd.) was placed in a four-loaf flask equipped with a reflux condenser, a stirrer, a thermometer, a nitrogen gas introduction tube, and a dropping funnel.
000) 300P and methyl ethyl ketone 900F were taken and heated and stirred at 80° C. while introducing nitrogen gas.

On the other hand, 69.6 P of 2,4-tolylene diisocyanate was placed in a dropping funnel and added dropwise to the reaction system over 60 minutes.

After the dropwise addition was completed, 1.17 f of stannous octylate was added, and the mixture was further heated and stirred at 80° C. for 2 hours, and the incyanate equivalent was measured from a small amount of the reaction product.

The incyanate equivalent of this product was 1,695.

Then, 20.8 g of trimellitic anhydride was added to the reaction product.
After adding S' and heating and stirring at 80° C. for 12 hours, the reaction was terminated.

During this time, the generation of carbon dioxide gas was confirmed from the cloudiness of the barium hydroxide aqueous solution.

The resulting reaction product is a yellowish brown viscous solution.

This solution was applied onto a germanium plate and the infrared absorption spectrum was measured.

The presence of an imide structure was confirmed by absorption of 1770crrL-1 and 720cIrL-1, and 2240c
The absorption of incyanate near rrL-1 almost disappeared, and 1720crtt” ~ 169 Qc
There was absorption due to urethane bonds near m'.

This confirmed that the product had amide-imide and urethane bonds.

A portion of the reaction product was poured into methanol to form a precipitate.

This precipitate was collected and dried under reduced pressure at 60° C. for 4 hours to obtain a pale yellow resin powder.

The softening temperature of this powder was around 70°C.

Next, add dicumyl peroxide 13 to the reaction product solution.
．． Add 67S' and stir until completely dissolved, then pour this solution into a glass cloth (Arisawa Seisakusho L92B silane treatment).
was impregnated with water and dried at 120°C for 5 minutes to obtain a pale yellow prepreg.

Layer 14 sheets of this prepreg at 170℃ and 150k.
When pressure molded at g/crA for 50 minutes, it becomes yellowish brown and has a thickness of 2.
A 5-piece laminate was obtained.

The general properties of this laminate were measured and are shown in Table B below.

Example 2 In a device similar to Example 1, 1,2 polybutadiene glycol (manufactured by Nippon Soda, N15so P BGlooo) was added.
)31', take 50 g of methyl ethyl ketone,
The mixture was heated and stirred to 80°C.

Next, 6.91' of 2,4-tolylene diisocyanate and 5 g of methyl ethyl ketone were placed in the dropping funnel and added dropwise to the reaction system over 30 minutes.

Thereafter, heating and stirring were continued at 80° C. for 1 hour, and 3.279 g of pyromellitic anhydride was added to the reaction system.

After the addition, the mixture was heated and stirred at 80'C for 8 hours to complete the reaction.

The reaction solution was a clear, yellow-brown viscous solution, and a portion of this solution was poured into methanol to form a precipitate.

This precipitate was collected and dried under reduced pressure at 60° C. for 5 hours to obtain a pale yellow resin powder.

The infrared absorption spectrum of this powder is 177ocrfL-1
, and 720CrIL' absorption reveals the presence of an imide structure.

The softening temperature of the powder was 82°C.

After adding 1.41 P of dicumyl peroxide to the remaining resin solution and stirring until it was completely dissolved, the solution was placed in an aluminum petri dish and cured at 180° C. for 2 hours.

The obtained cured resin had good curability and excellent heat resistance, and the thermal decomposition onset temperature (TGA) was 480°C.

Example 3 Into the same apparatus as in Example 1, 1,2 polybutadiene glycol (N15so P B G-1 manufactured by Nippon Soda) was added.
000) 60? , 12 og of methyl ethyl ketone were each weighed out and heated and stirred to 80°C.

Toluylene (2,6) diisocyanate in the dropping funnel,
(20%), toluylene (2,4) diisocyanate,
(80%) mixture 13. c+3? was measured and added dropwise over 60 minutes.

After heating and stirring at 80° C. for 90 minutes, 0.3 ml of triethylamine was added as a catalyst, and after 30 minutes, 3.849 g of trimellitic anhydride was added.

The reaction temperature was maintained at 80° C. and the mixture was heated and stirred for 8 hours to complete the reaction.

The reaction product obtained is a yellow-brown viscous solution.

Add 2.72f of dicumyl peroxide to this solution, dissolve it, and place a portion of this solution in an aluminum petri dish at 180 g.
Curing was carried out at ℃ for 30 minutes.

The thermal decomposition start temperature of this cured resin by TGA is 470°C.
It has excellent heat resistance.

The infrared absorption spectrum of the reaction product was similar to that of Example 1.

Example 4 In a reactor similar to Example 1, 1,2 polybutadiene glycol (Nippon Soda, KN15so P BGloo
o) 60 f was weighed out, 701 g of methyl ethyl ketone and 50 g of dimethyl formamide were added, and the mixture was heated and stirred to 80°C.

Next, 20.022 g of diphenylmethane diincyanate was weighed into the dropping funnel and added dropwise to the reaction system over 60 minutes.

After the dropwise addition was completed, heating and stirring were continued at 90° C. for 90 minutes, and 3.84 f of trimellitic anhydride was added.

The reaction was further heated and stirred at 90° C. for 10 hours to complete the reaction.

As in Example 1, the infrared absorption spectrum of the reaction product confirmed absorption by amide and imide groups and absorption by urethane bonds.

A portion of the resulting reaction solution was precipitated in methanol, and the precipitate was collected and dried at 60'C under reduced pressure.

The softening temperature of the dried resin powder was 110°C.

In addition, 2.93 ml of dicumyl peroxide was added to the remaining reaction solution.
S' was added and dissolved, and two portions of this solution were placed in an aluminum chalet and heated at 180'C for 30 minutes to obtain a yellowish brown transparent completely cured product.

Example 5 Using the resin solution obtained in Example 1, a molding material was obtained with the following formulation.

Resin solution (solvent, methyl ethyl 100 parts by weight ketone, solid content 31%) Calcium carbonate 110 Zinc stearate 2. o t-Butyl-benzoate 2. o〃Glass (1/4 inch, chopped) 2o〃After kneading these with a mixing roll for 1 hour, spread on aluminum and heat at 60° under reduced pressure.
Solvent removal was carried out at C for 2 hours.

This is crushed and pressure molded using a 30P circular mold for 170'c150 kg/cm for 5 minutes to form a molded product with a thickness of 2.4 to 2.67n7n with an excellent appearance. Goods were obtained.

The bending strength of this molded product after heating at 200° C. for 100 hours was 8.7 kg/vuA, which was no change from the initial value.

Example 6 Even after the resin solutions obtained in Examples 1 to 4 were left in a sealed container at room temperature for 2 months, no significant change in the viscosity of the solutions was observed and they were not usable in any way.

Claims (1)

[Claims] 11.2 Polybutadiene glycol and an organic diisocyanate are reacted to obtain a prepolymer having an isocyanate group at the end, and then the inocyanate group of the prepolymer is added to a tetracarboxylic acid (Ar represents an aromatic nucleus or a derivative thereof). A method for producing a thermosetting resin, which comprises reacting an acid anhydride and then blending a radical polymerization agent.