JP2002161188A - Thermosetting resin composition and its hardened matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition having dihydrobenzoxazine ring in which moldability and setting property are improved without lowering various properties such as mechanical property, and its hardened matter. SOLUTION: The thermosetting resin composition which consists of (A) a thermosetting resin having dihydrobenzoxazine ring, (B) a phenol resin and (C) a phosphorus accelerator, and the hardened matter are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to high-performance molding materials, paints, coatings, adhesives, sealing materials, sealing materials, prepregs for printed wiring boards, metal-clad laminates,
The present invention relates to a thermosetting resin composition used as a raw material for FRP and carbon products, and a cured product thereof.

[0002]

2. Description of the Related Art Thermosetting resins such as phenolic resins, melamine resins, epoxy resins, unsaturated polyester resins, and bismaleimide resins are used in many industrial fields due to their heat resistance and reliability based on their thermosetting properties. Used. However, phenolic resins and melamine resins generate volatile by-products during curing, epoxy resins and unsaturated polyester resins have poor heat resistance, and bismaleimide resins are very expensive. However, in reality, it is necessary to appropriately compromise on the problems depending on the application. Therefore, development of a novel thermosetting resin that does not have these problems has been promoted.

[0003] One of them is a dihydrobenzoxazine compound. (JP-A-49-47387, U.S. Pat. No. 5,152,939). Since the curing of this compound utilizes the ring-opening polymerization reaction of the dihydrobenzoxazine ring, it is thermally cured with almost no generation of volatile components.

Further, studies on curability and reactivity of these resins are described in J. A. Am. Chem. Soc. 3424
(1965), Burke et al., Polym. Sc
i. Technol. 27 (1985). Also, JP-A-7-188364 discloses that when a phenolic hydroxyl group in a molecule is converted into a dihydrobenzoxazine, the phenolic hydroxyl group is left at a specific ratio without being cyclized, thereby improving curability. Dihydrobenzoxazine compounds are described.

Further, Japanese Patent Application Laid-Open No. 9-272786 describes a thermosetting resin composition containing a dihydrobenzoxazine compound and a novolak-type phenol resin which has improved curability without deteriorating mechanical properties. I have.

[0006]

Problems to be Solved by the Invention
The cured product of the dihydrobenzoxazine compound utilizing the ring-opening polymerization reaction described in Japanese Patent Publication No. 7 has better heat resistance and higher strength than conventionally known thermosetting resins. However, curing by ring-opening polymerization has a disadvantage that it has a longer time than curing by ordinary curing reaction of a phenol resin, and there is also a problem that industrial applications are limited in terms of productivity. .

As described in JP-A-7-188364, when a certain ratio of phenolic hydroxyl groups is left in the molecule during dihydrobenzoxazine conversion, the resulting benzoxazine compound is cured. Although it has been confirmed that the ring opening reaction can be improved by heating during the synthesis of this compound,
There is a problem that it is difficult to perform stable synthesis.

Further, a report by Burke and Riess et al. Describes an example of studying curability when a monofunctional phenol compound is used, but the curability is not sufficiently improved, and the heat resistance due to a decrease in crosslink density is reduced. , A decrease in mechanical strength is observed.

Japanese Patent Application Laid-Open No. 9-272786 attempts to improve the curability of a dihydrobenzoxazine compound by using a novolak type phenol resin in combination.
Curability was still insufficient for application to molding materials and the like.

[0010] The present invention provides a thermosetting resin composition having a dihydrobenzoxazine ring, which has improved moldability and curability without deteriorating mechanical properties and other properties, and a cured product thereof. With the goal.

[0011]

That is, the present invention relates to (1) a thermosetting resin comprising (A) a thermosetting resin having a dihydrobenzoxazine ring, (B) a phenolic resin, and (C) a phosphorus-based curing accelerator. Curable resin composition. (2) The heat according to (1), wherein the phenol resin (B) is at least one of a phenol novolak resin, a phenol / aralkyl resin, a biphenyl-modified phenol resin, a xylene-modified phenol resin, a melamine-modified phenol resin, and a guanamine-modified phenol resin. Curable resin composition. (3) The thermosetting resin (A) having a dihydrobenzoxazine ring is a thermosetting resin synthesized from phenols, formaldehydes, and aromatic amines (1).
Or the thermosetting resin composition as described in (2). (4) The aromatic amines used in the thermosetting resin (A) having a dihydrobenzoxazine ring include anilines,
At least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, 1,3-bis (4-aminophenoxy) benzene and α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene The thermosetting resin composition according to any one of (3). (5) A cured product obtained by curing the thermosetting resin composition according to any one of (1) to (4).

[0012] The present invention also provides a cured product obtained by curing the thermosetting resin composition of the present invention.

As a result of extensive studies, the present inventors have found that a novolak-type phenol resin is blended as a curing agent with a thermosetting resin having a dihydrobenzoxazine ring, and a phosphorus-based curing accelerator is further blended. The present inventors have found that a thermosetting resin composition which hardens almost without generation of volatile components and has good properties such as mechanical properties can be obtained, and based on these findings, the present invention has been completed.

[0014]

DETAILED DESCRIPTION OF THE INVENTION (A) used in the present invention
The thermosetting resin having a dihydrobenzoxazine ring as a component is not particularly limited, but is preferably synthesized from phenols, aldehydes, and aromatic amines.

The phenol used in the synthesis of the thermosetting resin having a dihydrobenzoxazine ring as the component (A) is not particularly limited as long as it is a compound having a phenolic hydroxyl group. Examples thereof include phenol and o-cresol. , M-cresol, p-cresol, xylenol,
Monovalent alkylphenols such as ethylphenol, pt-butylphenol, nonylphenol, octylphenol, resorcinol, catechol, biphenol,
Polyphenols such as bisphenol A, bisphenol F, bisphenol S, and tetrafluorobisphenol A; naphthols such as α-naphthol, β-naphthol and dihydroxynaphthalene; or phenol derivatives such as phenylphenol, aminophenol and halogenated phenol These may be used alone or in combination of two or more.

The aldehyde used for synthesizing the thermosetting resin having a dihydrobenzoxazine ring as the component (A) is not particularly limited as long as it is a compound having an aldehyde group or an aldehyde source. For example, formaldehyde, formalin , Paraformaldehyde and the like. The paraformaldehyde having a formaldehyde concentration of 80% by weight or more, particularly a formaldehyde concentration of 92% by weight or more is preferable.

The aromatic amine used in the synthesis of the thermosetting resin having a dihydrobenzoxazine ring as the component (A) is not particularly limited as long as it is an amine derivative of an aromatic hydrocarbon. Toluidine, anisidine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4 '
-Diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 2,2-bis [(4-aminophenoxy) phenyl] propane, 1,3-bis (4-aminophenoxy) benzene, α, α'-bis (4 Aromatic diamines such as -aminophenyl) -1,4-diisopropylbenzene (commonly known as bisaniline-M); one of these may be used alone, or two or more may be used in combination. Above all, from the viewpoint of workability and property improvement,
4,4′-diaminodiphenylmethane and 4,4′-diaminodiphenyl ether are preferred, and from the viewpoint of flame retardancy, 1,3-bis (4-aminophenoxy) benzene and α, α′-bis (4-aminophenyl) ) -1,4-
Diisopropylbenzene is preferred.

When a diamine is used, a monohydric phenol is used. When a monoamine is used, bisphenol A is used.
The thermosetting resin (A) having two or more dihydrobenzoxazine rings can be produced by using F and a novolak type phenol resin.

The method for synthesizing the thermosetting resin (A) having a dihydrobenzoxazine ring is not particularly limited, and examples thereof include a method of reacting phenols with aldehydes and aromatic amines in a solvent. Above all, after suspending phenols and aldehydes in a solvent, 50
７０70 ° C., the aromatic amines are added over 15-30 minutes, then the reaction temperature is raised to the reflux temperature (about 80 ° C.), 1-4 hours after emulsification, more preferably about 2 hours. It is preferable to carry out the reaction for a period of time and, after completion of the reaction, remove the solvent and water under reduced pressure. If the temperature at the time of adding the aromatic amines is less than 50 ° C., the reaction proceeds without dissolving the aromatic amines and aldehydes, and unreacted aromatic amines and aldehydes tend to remain in the reaction system, If the temperature exceeds 70 ° C., the reaction partially proceeds, and it tends to be difficult to obtain a uniform resin.

The solvent used in the reaction is not particularly restricted but includes lower alcohols such as methanol, ethanol, propanol and butanol. Of these, methanol is preferred from the viewpoints of cost and affinity with aldehydes.

The thermosetting resin having a dihydrobenzoxazine ring as the component (A) has a temperature of 150 ° C. or higher, preferably 1 ° C.
By heating to 70 to 220 ° C., curing can be performed without generating by-products without using a catalyst or a curing agent.

As the thermosetting resin (A) having a dihydrobenzoxazine ring, one type may be used alone, or two or more types may be used in combination.

The phenolic resin of the component (B) used in the present invention is not particularly limited, and for example, phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol and / or the like. Or a phenol novolak resin, a naphthol novolak resin, a phenol and / or a naphthol such as α-naphthol, β-naphthol, dihydroxynaphthalene and a compound having an aldehyde group such as formaldehyde obtained by condensation or co-condensation thereof under an acidic catalyst. Or a phenol-aralkyl resin synthesized from naphthols and dimethoxyparaxylene or bis (methoxymethyl) biphenyl;
Aralkyl resins, xylene-modified phenolic resins, naphthol-modified phenolic resins, naphthalene-modified phenolic resins, biphenyl-modified phenolic resins, melamine-modified phenolic resins, guanamine-modified phenolic resins, and the like. These may be used alone or in combination of two or more. May be used. Among them, phenol-aralkyl resins, xylene-modified phenol resins, and biphenyl-modified phenol resins are preferred from the viewpoint of lowering the viscosity and increasing the filling.
From the viewpoint of flame retardancy, melamine-modified phenol resins and guanamine-modified phenol resins are preferred. When using at least one of a phenol-aralkyl resin, a xylene-modified phenol resin, a biphenyl-modified phenol resin, a melamine-modified phenol resin, and a guanamine-modified phenol resin, the compounding amount is based on the total amount of the phenol resin in order to exhibit its performance. It is preferable that the total amount is 60% by weight or more.

As the phosphorus-based curing accelerator used in the present invention, tributylphosphine, dibutylphenylphosphine, butyldiphenylphosphine, ethyldiphenylphosphine, methyldiphenylphosphine, triphenylphosphine, tri-p-tolylphosphine, tris (4- Organic phosphines such as methylphenyl) phosphine, tris (4-methoxyphenyl) phosphine, tris (2,6-dimethoxyphenyl) phosphine, diphenylphosphine and phenylphosphine, and maleic anhydride, 1,4- Benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,
Quinones such as 3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone and phenyl-1,4-benzoquinone Compounds, diazophenylmethane, phosphorus compounds having an intramolecular polarization obtained by adding a compound having a π bond such as a phenol resin, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, and the like. From the viewpoint of properties, organic phosphines or those obtained by adding a quinone compound to organic phosphines are preferable, and triphenylphosphine, tri-p-
An adduct of a tertiary phosphine such as tolylphosphine, tris (4-methylphenyl) phosphine or tris (4-methoxyphenyl) phosphine with a quinone compound such as 1,4-benzoquinone or 1,4-naphthoquinone is more preferable. These curing accelerators may be used alone or in combination of two or more.

The amount of the phosphorus-based curing accelerator is not particularly limited as long as the curing acceleration effect is achieved, but is preferably 0.005 to 5% by weight based on the resin composition. Preferably it is 0.01 to 2% by weight. 0.0
If it is less than 05% by weight, the curability tends to be poor, and 5% by weight
If it exceeds 300, the curing rate tends to be too high and it is difficult to obtain a good molded product.

The thermosetting resin having a dihydrobenzoxazine ring, the phenol resin, and the curing accelerator may be finely pulverized by a mixer or the like and then mixed with a powder. May be dissolved and mixed therein.

Further, a filler, a reinforcing fiber, a release agent, a coloring agent, an adhesive, and the like can be added to the composition as required.

The resin composition of the present invention is kneaded with a heating roll or the like, and thereafter, at a temperature of 180 to 220 ° C. and a molding thickness of 2 to 7 MP.
a, which is cured by compression molding or transfer molding for 5 to 30 minutes to obtain a cured product which is more excellent in curability than the thermosetting resin having a dihydrobenzoxazine ring alone, and has good mechanical properties and flame retardancy. it can.

The cured product is further heated at 180 to 220 ° C.
By post-curing for 5 to 120 minutes, a cured product having better properties can be obtained.

The thermosetting resin composition of the present invention can be used, for example, in accordance with its use, for example, metal-clad laminate, molding material, sealing material,
For applications such as RP resin materials, an epoxy resin and its curing agent may be added.

The epoxy resin used as an additive component is not particularly limited, and may be a polyphenolic acid such as a phenol novolak type epoxy resin, an orthocresol novolak type epoxy resin, a biphenyl type epoxy resin, bisphenol A, bisphenol F or bisphenol S. Glycidyl ester type epoxy resin obtained by reaction of epichlorohydrin, glycidylamine type epoxy resin obtained by reaction of polyamine such as diaminodiphenylmethane and epichlorohydrin, linear aliphatic epoxy obtained by oxidizing olefin bond with peracid such as peracetic acid There are a resin, an alicyclic epoxy resin, a brominated epoxy resin and the like, and these may be used alone or in combination of two or more. The curing agent for the epoxy resin is not particularly limited, but is preferably one that does not generate volatile components during curing, particularly, a novolak-type phenol resin, dicyandiamide,
Polyaddition curing agents such as imidazoles and triphenylphosphine are preferred. When a novolak-type phenol resin is used as a curing agent for the epoxy resin, in addition to the amount of the novolak-type phenol resin described for the thermosetting resin composition, 1 mole of epoxy groups of the epoxy resin is added. It is preferable to add an amount of the novolak phenol resin in which the hydroxyl group of the novolak phenol resin is usually 0.5 to 1.5 mol.

The thermosetting resin composition of the present invention has heat resistance,
High-performance molding materials, paints,
It is suitably used as a resin material for coating materials, adhesives, sealing materials, prepregs for printed wiring boards, metal-clad laminates, FRP, carbon products and the like.

For example, the thermosetting resin composition of the present invention may be used as it is, or as necessary, a filler, a reinforcing fiber, a release agent,
By adding a coloring agent or the like, it can be used as a sealing material for sealing various molding materials, semiconductor elements and the like. Further, by impregnating a substrate such as a glass cloth with a varnish containing the thermosetting resin composition of the present invention and, if necessary, a filler and the like, and drying by heating, a prepreg used for manufacturing a printed wiring board is obtained. Obtainable. A metal-clad laminate can be obtained by stacking a plurality of the prepregs, further arranging a metal foil such as a copper foil on one or both sides thereof, and applying heat and pressure. Printed wiring boards produced using the prepregs and metal-clad laminates thus obtained are excellent in heat resistance and flame retardancy, and thus are suitably used in various electric and electronic fields.

[0034]

EXAMPLES Next, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

Synthesis Example 1 (Synthesis of thermosetting resin (I) having dihydrobenzoxazine ring) Bisphenol F (1.00 kg, 5 mol), 95% paraformaldehyde 0.63 kg (20
Mol) and 900 ml of methanol, and paraformaldehyde was suspended in phenol while heating under reflux. When the suspension reaches 50 ° C., 0.93 kg of aniline
(10 mol) was added in portions, and after the addition was completed, the reaction temperature was increased to carry out a reflux reaction. After the reaction liquid was emulsified, the reaction was continued for 2 hours. After the reaction was completed, the solvent and by-produced water were distilled off under reduced pressure to obtain a thermosetting resin having a dihydrobenzoxazine ring. 1 of the obtained thermosetting resin
The melt viscosity at 50 ° C. was 0.8P.

Synthesis Example 2 (Synthesis of thermosetting resin (II) having dihydrobenzoxazine ring) 1.08 kg (10 mol) of o-cresol, 0.63 kg (20%) of 95% paraformaldehyde
Mol) and 900 ml of methanol, and paraformaldehyde was suspended in phenol while heating under reflux. When the temperature of the suspension reached 50 ° C., 0.99 kg (5 mol) of 4,4′-diaminodiphenylmethane was added in portions, and after the addition was completed, the reaction temperature was increased to perform a reflux reaction. After the reaction liquid was emulsified, the reaction was continued for 2 hours. After the reaction was completed, the solvent and by-produced water were distilled off under reduced pressure to obtain a thermosetting resin having a dihydrobenzoxazine ring.
The melt viscosity at 150 ° C. of the obtained thermosetting resin was 1.1P.

Synthesis Example 3 (Synthesis of novolak type phenol resin) Phenol
4 kg, 0.13 kg of 37% formalin aqueous solution, 0.5 kg of paraformaldehyde, and 3 g of oxalic acid were charged into a 5-liter flask and reacted at reflux temperature for 4 hours. And water were removed to obtain a novolak type phenol resin. The melt viscosity at 150 ° C. of the obtained novolak type phenol resin was 2P.

[Curing] The resin composition obtained above was pulverized, filled into a mold having an inner diameter of 120 mm × 80 mm × 4 mm, and heated and pressed at 180 ° C. and 1.96 MPa for 15 minutes to produce a cured product. .

Examples 1 to 6 and Comparative Examples 1 to 8 As the thermosetting resin having a dihydrobenzoxazine ring, the thermosetting resin obtained in Synthesis Examples 1 and 2 and the novolak obtained in Synthesis Example 3 above were used. Table 1 and Table 2 show a phosphorus-based curing accelerator (an adduct of triphenylphosphine and 1,4-benzoquinone), imidazole and hexamethylenetetramine as the type phenol resin and the curing accelerator, respectively.
And the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were prepared, and the characteristics were evaluated.

[0040]

[Table 1] The prepared resin compositions of Examples and Comparative Examples and cured products thereof were evaluated by the following tests. Table 2 shows the evaluation results. (1) Gelation time 0.3 g of the resin composition was stirred on a gel timer heated to 180 ° C. once a second for one second to determine the time until stringing disappeared. (2) Bending test Using a test piece molded under the conditions of 180 ° C., 90 minutes and 7 MPa, JIS-K- was used with Tensilon manufactured by Shimadzu Corporation.
A bending test of a three-point support type in accordance with 6911 was performed, and bending strength (MPa), flexural modulus (GPa), and elongation at break (%) were determined. The measurement was performed using a test piece of 80 mm × 10 mm × 3 mm at room temperature or 215 ° C. under the condition of a head speed of 1.5 mm / min. (3) Glass transition temperature, coefficient of linear expansion Thermomechanical analyzer (TMA-814, manufactured by Rigaku Corporation)
5mm × 3mm × 3 by 1BS, TAS-100)
Using a test piece having a shape of mm, the measurement was performed at a temperature rising rate of 5 ° C./min. The glass transition temperature (Tg, unit: ° C.) was determined from the inflection point of the linear expansion curve, and the linear expansion coefficient (E ⁻⁵ / ° C.) was determined from the slope below Tg. (4) Water absorption 50 mm x 50 mm x 3 mm thick resin plate
CT (Pressure Cooker Tester) (121
(2 ° C., 2 ° C.) for 20 hours, and was determined from the weight change before and after humidification.

[0041]

[Table 2] Comparative Examples 1 to 3 containing no component (B) in the present invention are:
The gelation time was long and the curability was poor. In Comparative Examples 4 and 5 using a curing accelerator other than the component (C), the curability was good, but the water absorption was high. Comparative Example 6 containing no component (A) also had good curability, but had a very high water absorption. Comparative Examples 7 and 8, which did not contain the component (C), had a long gelation time and were inferior in curability.

On the other hand, Examples 1 to 6 containing all the components (A) to (C) of the present invention show a short gelation time, a low water absorption, and excellent moldability and curability. Was done.

[0043]

The thermosetting resin composition and the cured product according to the present invention have good moldability and low hygroscopicity as shown in the examples, and have excellent curability and mechanical properties. Therefore, its industrial value is great.

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Claims (5)

[Claims] 1. A thermosetting resin having (A) a dihydrobenzoxazine ring, (B) a phenol resin, and (C)
A thermosetting resin composition comprising a phosphorus-based curing accelerator. 2. The method according to claim 1, wherein the phenol resin (B) is at least one of a phenol novolak resin, a phenol / aralkyl resin, a biphenyl-modified phenol resin, a xylene-modified phenol resin, a melamine-modified phenol resin, and a guanamine-modified phenol resin. The thermosetting resin composition according to the above. 3. The thermosetting resin according to claim 1, wherein the thermosetting resin (A) having a dihydrobenzoxazine ring is a thermosetting resin synthesized from phenols, formaldehydes, and aromatic amines. Resin composition. 4. An aromatic amine used in the thermosetting resin (A) having a dihydrobenzoxazine ring is aniline, 4,4′-diaminodiphenylmethane, 4,4 ′.
The thermosetting composition according to claim 3, which is at least one of -diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, and α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene. Resin composition. 5. A cured product obtained by curing the thermosetting resin composition according to claim 1.