JPH11106466A - Production of phenolic resin-based flame-retardant self hardening resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce the subject flame-retardant resin containing no halogen element by reacting a phenolic compound with an aldehyde and an aromatic amine in a solvent, and subsequently reacting the reaction product with an phosphoric acid ester. SOLUTION: This resin is obtained by reacting (A) a phenolic compound (e.g. phenol) with (B) an aldehyde (e.g. paraformaldehyde) and (C) an aromatic amine (e.g. 4,4'-diaminodiphenylmethane) preferably in (D) an alcoholic solvent (e.g. methanol), and subsequently adding (E) a phosphoric acid ester (e.g. triphenyl phosphate) to the reaction mixture and reacting them with each other. Concretely, into the D component are added the component B and the component A, and a part or the whole of the components A and B is dissolved. Subsequently, the reaction mixture is cooled to <=70 deg.C, then the component C is added, and the reaction is continued at the refluxing temperature. When it reaches a specific getting time, the reaction mixture is concentrated under reduced pressure to remove the component D, water, etc. During this process, the component E is added, and it is made to react with the reaction mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant and heat-resistant material which does not contain a halogen element and which is most suitable for electronic materials such as laminates used for printed circuit boards and multilayer printed circuit boards and semiconductor encapsulants. The present invention relates to a method for producing a phenol resin-based flame-retardant self-curing resin which is a thermosetting resin having the same.

[0002]

2. Description of the Related Art A phenol resin is a resin synthesized by reacting a phenol with formaldehyde in the presence of a basic or acidic catalyst. Generally, a self-curing resol type phenol resin is used under a basic catalyst. In the presence of an acidic catalyst, a thermoplastic novolak-type phenol resin is obtained. The novolak-type phenol resin does not cure by itself, but requires a curing agent such as hexamethylenetetramine. These phenolic resins have the disadvantage of generating low molecular weight gases such as water, formaldehyde, and ammonia during curing.

[0003]

Japanese Patent Application Laid-Open No. 49-47378 discloses a phenol resin which is polymerizable and does not produce by-products of a low-molecular compound with respect to a phenol resin which generates a low-molecular gas at the time of curing. And resins having an oxazine ring synthesized from formaldehyde, primary diamine and phenol. Although this resin has good performance without the above-mentioned disadvantages, it is difficult to isolate the synthesized resin by the method disclosed in this patent. That is, the reaction system contains water produced by a polycondensation reaction from formaldehyde, phenols, aromatic amines and formaldehyde generated from a formalin source, and it is necessary to remove water and unreacted components from the reaction system. Usually, a method is employed in which the unreacted components and moisture are distilled out together with the system by heating under reduced pressure.

However, since these vacuum distillations are carried out while heating the reaction system, the polycondensation reaction proceeds to increase the molecular weight. In this case, the melt viscosity of the resin in the system increases, and in some cases, stirring becomes impossible, it is difficult to take out the formed resin out of the system and proceed to the next step, or the yield decreases. Or For this reason, when distilling under reduced pressure, it is necessary to prevent this from happening, which requires careful attention such as temperature and viscosity control, complicates the process, and increases the cost of the obtained resin. I was In recent years, regulations on halides used in materials have been increasing from the viewpoint of environmental pollution and toxicity. Above all, toxicity of organic halogen substances such as dioxin has become a problem, and reduction and elimination of halogen-containing substances have been strongly demanded. However, in order to ensure safety during use, materials used are required to have flame retardancy. A phenol resin is a resin that is relatively inflammable, but it is difficult to satisfy the UL standard flame retardancy V-0 with a phenol resin alone. In order to satisfy the flame retardancy without containing any halogen element, Required the addition of a non-halogen flame retardant. However, these additions deteriorate properties such as solvent resistance and heat resistance. An object of the present invention is to provide a method for producing a flame-retardant resin which is a flame-retardant resin containing no halogen element and which can be easily synthesized.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for producing a phenolic resin-based self-curable resin containing an oxazine ring obtained by reacting phenols, aldehydes and primary amines. This is a method for producing a phenolic resin-based flame-retardant self-curing resin in which a phenol resin-based flame-retardant resin is prepared by reacting a phenol, an aldehyde and an aromatic amine to obtain a reaction solution, and then mixing and reacting a phosphoric ester. And when to mix phosphates, phenols,
A phenolic resin-based flame-retardant resin is preferably used when the aldehydes and aromatic amines are reacted, the reaction solution is concentrated under reduced pressure, and the solvent, unreacted components and water generated by the condensation reaction are added to the system when it is removed from the system. This is a method for producing a curable resin. In the present invention, the solvent used in the production of the resin is an alcohol solvent, and the alcohol solvent is methanol, ethanol, n-, i-propanol, n-, i
It is preferable that at least one selected from-and t-butanol is used. Further, in the present invention,
The aldehydes are paraforms having a formaldehyde content of 92% by weight or more, and the aromatic amines are
4,4'-diaminodiphenylmethane is a method for producing a phenol resin-based flame-retardant self-curable resin which is preferable.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have investigated the viscosity of the reaction product of a modified phenolic resin-based self-curable resin having an oxazine ring obtained by reacting the above-mentioned phenols, aldehydes and primary amines. A modified phenol resin having an oxazine ring in a concentration step under reduced pressure in which a phosphate ester is blended, and dehydration, desolvation, etc. is performed as a means for improving the flame retardancy by lowering the production process. It has been found that the above object can be achieved by reacting the compound with a phosphoric acid ester.

According to the present invention, an oxazine ring is provided which comprises reacting an aromatic monoamine or aromatic diamine in a reaction system with as little water as possible other than water produced by dehydration condensation from a phenol and an aldehyde. It is more preferable to use paraform than formalin as a formaldehyde source in order to reduce the water content in the system, which is convenient for the synthesis of a polymer having The water generated by the dehydration condensation reaction and the water contained in the formaldehyde source are usually removed by heating under reduced pressure as described above. However, the polycondensation reaction proceeds during the heating dehydration and solvent removal steps, and the viscosity increases simultaneously with the polymerization. When the viscosity increases, stirring becomes difficult, sometimes the stirring ability is insufficient, and the resin sticks to the stirring blade, and stirring becomes impossible. In addition, it becomes difficult to take out the resin from the synthesis kettle, it takes time, and the performance may be different between the resin at the initial stage and the resin at the last stage taken out from the reaction kettle, which may cause variations in products. Become. The present inventors, while adding a phosphate ester, in order to increase viscosity under reduced pressure, flame retardancy and product stability,
It was found that the above-mentioned disadvantages were eliminated by concentration, and the present invention was reached.

In the present invention, a part or all of aldehydes and phenols are dissolved using a solvent, and then the temperature of the reaction system is reduced to 70 ° C. or lower, and an aromatic monoamine or aromatic diamine is exothermically reacted. While increasing the temperature rise due to the above. After completion of the addition, the reaction is continued at the reflux temperature. Then, the reaction end point is reached when a predetermined gel time has elapsed. When the resin and the solvent are separated into two layers, in order to facilitate concentration, it is more efficient to decant and concentrate the solvent layer under reduced pressure after pumping out the solvent layer by decantation or a pump. Then, a phosphate ester is added and the mixture is concentrated under reduced pressure.

The phenols used in the present invention include monophenols such as phenol, o-, m-, p-cresol, xylenol, nonylphenol, p-, t-butylphenol and octylphenol, and bisphenol-A and bisphenol-F. And polyhydric phenols such as novolak type phenol resin.

The aldehydes include formalin and paraform, with paraform being preferred. Paraholm is 8
With a formaldehyde concentration of 0% by weight or more, especially 92%
Those having a concentration of not less than% by weight are preferred.

The aromatic monoamines include aniline and toluidine, and the aromatic diamines include m-phenylenediamine, p-phenylenediamine, 4,4'-
Examples thereof include diaminodiphenylmethane, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylsulfone, and 2,2-bis [(4-aminophenoxy) phenyl] propane. Among them, 4,4'-diaminodiphenylmethane is preferable because of its excellent balance of reactivity, heat resistance and the like.

As the solvent used in the reaction, there can be used an aromatic hydrocarbon solvent, a ketone solvent, an alcohol solvent, an ether solvent, a chlorinated solvent, and the like. The use of a system solvent is preferred because it has a good affinity for aldehydes. Examples of the alcohol solvent include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol and the like. Particularly, methanol is preferable from the viewpoint of price and affinity with paraform.

Examples of the phosphoric ester include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, xylerdiphenyl phosphate, CR-757, CR-733S, CR-741, C-741
R-747, PX-200 (all trade names, manufactured by Daihachi Chemical Industry Co., Ltd.) and the like. Low molecular triphenyl phosphate and cresyl diphenyl phosphate are preferred because of their good viscosity and solubility.

The reaction conditions are as follows: aldehydes and phenols are dissolved or suspended in a solvent, and then aromatic monoamines or aromatic diamines are added. The addition of aromatic amines is preferably performed at a reaction system temperature of 20 ° C to 90 ° C. If the temperature is lower than 20 ° C., the reaction proceeds without dissolving the aromatic amines and aldehydes, and unreacted aldehydes and aromatic amines remain in the reaction system, which is not preferable as a resin. On the other hand, when the temperature exceeds 90 ° C., the reaction partially proceeds, and a uniform resin may not be obtained. The amount of the solvent used is 0.5 to 2.0 times the amount of the aldehyde,
In particular, it is preferably 1.0 to 1.5 times. If less than 0.5 times,
The unreacted raw materials remain in the resin because the undissolved portions of the aldehydes increase to make it difficult to react uniformly. Also, 2.0
If it exceeds twice, it takes a lot of time to remove the solvent at the time of concentration under reduced pressure, the amount of waste increases, and the cost increases, which is not preferable.

The amount of the phosphoric acid ester used is not particularly limited, but the total amount of phenols and aromatic amines is 100%.
5 to 50 parts by weight are appropriate as parts by weight. If the amount is less than 5 parts by weight, the effect of lowering the viscosity is small, and if it exceeds 50 parts by weight, the polycondensation reaction hardly proceeds and the reaction time becomes long. The reaction system is separated into a resin layer and a solvent layer depending on the amount of the solvent used. If separated, removal of water by-products from the reaction with phenols, aldehydes and aromatic amines,
In order to simplify the concentration process under reduced pressure, it is efficient to pump up the solvent layer with a decanter or a pump to make only the resin layer and to add phosphate esters. If separation does not occur, phosphoric acid esters are added to the reaction solution after completion of the reaction, concentrated under reduced pressure, and concentrated under reduced pressure.

When concentrated in the presence of phosphates,
High molecular weight of the resin having an oxazine ring is suppressed,
The increase in viscosity is small, and it is easy to remove the reactants from the kettle. In addition, the flame retardancy of phosphoric acid esters has improved the flame retardancy of the phenolic resin-based flame-retardant self-curing resin of the oxazine ring-containing resin synthesized, and the resin shows sufficient flame retardancy without halogen atoms. Can be provided.

The phenolic resin flame-retardant self-curing resin according to the present invention is different from the conventional phenolic resin in that water is not produced as a by-product during curing. Can be applied to the field. For example, the present invention can be applied to the field of electronics such as glass cloth laminates and sealing materials, and the field of binders such as molding materials and friction materials. Hereinafter, the present invention will be described more specifically with reference to Examples.

[0018]

【Example】

Example 1 Paraform 652 containing 940 g (10 mol) of phenol, 900 ml of methanol and 92% by weight was placed in a 5-liter flask equipped with a thermometer, a stirrer and a condenser.
g (20 mol) was added and heated under reflux to suspend paraform in phenol. When the suspension reaches 50 ° C,
990 g (5 mol) of 4'-diaminodiphenylmethane were added in portions. After the addition is completed, raise the reaction temperature,
Refluxed. The reaction liquid showed emulsification, and the reaction was continued for 2 hours after emulsification. After the completion of the reaction, triphenyl phosphate 1
After adding 50 g, the solvent and by-product water were distilled off under reduced pressure. The end point of the reaction was the time when the gel time on a hot plate at 160 ° C. became 5 minutes. After completion of the reaction, the reaction product was poured from the flask into a metal vat coated with Teflon, allowed to cool, and then crushed to obtain a resin powder. 50 g of the resin powder obtained above was added to methyl ethyl ketone (MEK) 25
g to prepare a varnish. The varnish was applied to a polyethylene terephthalate (PET) film treated with a release agent, and heated with a drier to evaporate the solvent to prepare a resin in a B-stage state. This resin was peeled off from the PET film, and a predetermined amount was put into a cavity made of a Teflon mold frame cut into a 50 mm × 50 mm placed on a stainless steel end plate.
The resin was heated and pressed under the conditions of 40 kg / cm ² for 0 minute to produce a resin plate having a thickness of 1.5 mm. The glass transition temperature of the resin plate was 148 ° C. as measured by a viscoelasticity method. The flame retardancy was V-0 according to the UL-94 test method.

(Example 2) In the same manner as in Example 1, 1080 g (10 mol) of m-, p-cresol, 500 ml of isopropanol, 631.6 g (20 mol) of paraform containing 95% by weight were charged into a flask. After heating under reflux, paraform was suspended in m-, p-cresol.
When the suspension reached 50 ° C., 990 g (5 mol) of 4,4′-diaminodiphenylmethane were added in portions. After the addition was completed, the reaction temperature was raised to reflux. The reaction liquid showed emulsification, and the reaction was continued for 2 hours after emulsification. After the reaction is completed, cresyl diphenyl phosphate 10
0 g was added. Thereafter, the solvent and by-product water were distilled off under reduced pressure. The end point of the reaction was the point in time when the gel time on a hot plate at 160 ° C. became 6 minutes. After the reaction,
The reaction product was poured from the flask into a metal vat coated with Teflon, allowed to cool, and then crushed to obtain a resin powder. 50 g of the resin powder obtained above was added to methyl ethyl ketone (ME
K) Dissolved in 25 g to produce a varnish. The varnish was applied to a PET film treated with a release agent, and heated with a drier to produce a B-stage resin in which the solvent was evaporated. This resin was peeled off from the PET film, and a predetermined amount was put into a cavity made of a Teflon mold that was cut into a 50 mm × 50 mm placed on a stainless steel end plate.
The resin plate having a thickness of 1.5 mm was produced by heating and pressing under the condition of cm ² . The glass transition temperature of the resin plate was 144 ° C. as measured by a viscoelasticity method. The flame retardancy was V-0 according to the UL-94 test method.

Example 3 In the same manner as in Example 1, m-, p-cresol (1080 g, 10 mol), isopropanol (500 ml), and paraform containing 631.6 g (20 mol) containing 95% by weight were charged into the flask. After heating under reflux, paraform was suspended in m-, p-cresol.
When the temperature of the suspension reached 50 ° C., 1,000 g (5 mol) of 4,4′-diaminodiphenyl ether was added in portions. After the addition was completed, the reaction temperature was raised to reflux. The reaction liquid showed emulsification, and the reaction was continued for 2 hours after emulsification. After completion of the reaction, 200 g of CR-757 (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.) was added to the reaction solution in the flask. Thereafter, the solvent and by-product water were distilled off under reduced pressure. The end point of the reaction was the time when the gel time on a hot plate at 160 ° C. became 4 minutes. After completion of the reaction, the reaction product was poured from the flask into a metal vat coated with Teflon, allowed to cool, and then crushed to obtain a resin powder. 50 g of the resin powder obtained above was dissolved in 25 g of methyl ethyl ketone (MEK) to prepare a varnish. PET with the varnish treated with a release agent
The resin was applied to a film and heated by a dryer to produce a resin in a B-stage state in which the solvent was volatilized. This resin is PET
50mm peeled from the film and placed on a stainless steel head
A predetermined amount is put into a cavity made of a Teflon mold that has been cut out to × 50 mm, and a stainless steel head plate is further stacked.
It was heated and pressed at 40 ° C./cm ² at 170 ° C. for 90 minutes to produce a resin plate having a thickness of 1.5 mm. The glass transition temperature of the resin plate was 215 ° C. as measured by a viscoelasticity method. The flame retardancy was V-0 according to the UL-94 test method.

Example 4 In the same manner as in Example 1, 1140 g (5 mol) of bisphenol-A was placed in a flask,
500 ml of isopropanol, 631.6 g (20 mol) of paraform containing 95% by weight were added, and the mixture was heated under reflux,
Paraform and bisphenol-A were suspended in isopropanol. When the suspension reaches 50 ° C., aniline 93
0 g (10 mol) were added in portions. After the addition was completed, the reaction temperature was raised to reflux. The reaction liquid showed emulsification, and the reaction was continued for 2 hours after emulsification. After the reaction, CR-733S (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.) is added to the flask.
300 g were added. Thereafter, the solvent and by-product water were distilled off under reduced pressure. The end point of the reaction was a point in time when the gel time on a hot plate at 160 ° C. reached 4 minutes and 30 seconds. After the reaction was completed, the mixture was poured from the flask into a metal vat coated with Teflon, allowed to cool, and then crushed to obtain a resin powder. 50 g of the resin powder obtained above was added to methyl ethyl ketone (ME
K) Dissolved in 25 g to produce a varnish. The varnish was applied to a PET film treated with a release agent, and heated with a drier to produce a B-stage resin in which the solvent was evaporated. This resin was peeled off from the PET film, and a predetermined amount was put into a cavity made of a Teflon mold that was cut into a 50 mm × 50 mm placed on a stainless steel end plate.
The resin plate having a thickness of 1.5 mm was produced by heating and pressing under the condition of cm ² . The glass transition temperature of the resin plate was 186 ° C. as measured by a viscoelasticity method. The flame retardancy was V-0 according to the UL-94 test method.

Comparative Example 1 940 g (1) of phenol was placed in a 5-liter flask equipped with a thermometer, a stirrer, and a cooler.
0 mol), methanol (900 ml), and 652 g (20 mol) of paraform containing 92% by weight, and heated under reflux to suspend paraform in phenol. When the suspension reaches 50 ° C., 990 g of 4,4′-diaminodiphenylmethane
(5 mol) were added in portions. After the addition was completed, the reaction temperature was raised to reflux. The reaction liquid showed emulsification, and the reaction was continued for 2 hours after emulsification. After completion of the reaction, the solvent and by-product water were distilled off under reduced pressure. The end point of the reaction is 160
The time when the gel time on the hot plate at 5 ° C. became 5 minutes was set.
After completion of the reaction, the reaction product was poured from the flask into a metal vat coated with Teflon, allowed to cool, and then crushed to obtain a resin powder. However, an attempt was made to inject the resin from the flask into a metal vat coated with Teflon, but the viscosity of the resin was so high that the resin adhered to the wall of the flask and could not be completely removed from the flask. 50 g of the resin powder obtained above was dissolved in 25 g of methyl ethyl ketone (MEK) to prepare a varnish. The varnish was applied to a polyethylene terephthalate (PET) film treated with a release agent, and heated with a drier to evaporate the solvent to prepare a resin in a B-stage state. This resin was peeled off from the PET film, and a predetermined amount was put into a cavity made of a Teflon mold that was cut into a 50 mm × 50 mm placed on a stainless steel end plate.
The resin plate having a thickness of 1.5 mm was produced by heating and pressing under the condition of cm ² . The glass transition temperature of the resin plate was 215 ° C. as measured by a viscoelasticity method. The flame retardancy was V-1 in the UL-94 test method. In the comparative example, when the end point of the reaction was a point in time when the gel time on the hot plate at 160 ° C. became 15 minutes, the resin could be taken out without fixing to the vessel wall to the flask. However, a large amount of unreacted phenol was mixed in and phenol was generated during curing.

[0023]

According to the method for producing a phenolic resin flame-retardant self-curing resin of the present invention, as shown in the examples, phosphoric esters are added to a resin having an oxazine ring synthesized by reacting in a solvent. This makes it easier to take out the reaction product from the reaction vessel to the outside of the system, and also has excellent heat resistance, flame retardancy, and handleability that is excellent in flame retardancy because it contains phosphorus element. Can be provided.

Claims (6)

[Claims] 1. A method for producing a phenolic resin-based self-curable resin containing an oxazine ring obtained by reacting a phenol, an aldehyde and a primary amine, wherein the phenol, the aldehyde and the aromatic amine are dissolved in a solvent. A phenolic resin-based flame-retardant self-curing resin, wherein a phosphoric acid ester is blended and further reacted after obtaining a reaction solution. 2. A phenol, an aldehyde and an aromatic amine are reacted in a solvent, the reaction solution is concentrated under reduced pressure, and a phosphate ester is used when removing the solvent and water generated by the condensation reaction out of the system. The method for producing a phenolic flame-retardant self-curable resin according to claim 1, wherein the phenolic resin is blended and concentrated under reduced pressure. 3. The solvent according to claim 1, wherein the solvent is an alcohol solvent.
Alternatively, the method for producing a phenolic resin-based flame-retardant self-curable resin according to claim 2. 4. The phenolic resin according to claim 3, wherein the alcohol solvent is at least one selected from methanol, ethanol, n-, i-propanol, n-, i-, and t-butanol. A method for producing a flame-retardant self-curing resin. 5. The method for producing a phenolic resin-based flame-retardant self-curable resin according to claim 1, wherein the aldehyde is paraform having a formaldehyde content of 92% by weight or more. 6. The method for producing a phenolic resin flame-retardant self-curing resin according to claim 1, wherein the aromatic amine is 4,4′-diaminodiphenylmethane.