JPH09278985A - Thermosetting resin composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermosetting resin composition capable of giving cured products with high toughness and excellent mechanical properties and flame retardancy, and useful as a raw material for highly functional molding materials, coating materials, sealants, laminates, etc., comprising a specific thermosetting resin and a liquid elastomer. SOLUTION: This composition comprises (A) a dihydrobenzoxazine ring- bearing thermosetting resin for example, having in one molecule structural unit X1 of formula I[the H atoms on the aromatic ring may be replaced with 1-3C alkyl (Z) except for one on the ortho site relative to the OH group] and structural unit X2 of formula II (R<1> is methyl, etc.; the H atoms on the aromatic ring may be replaced with Z, etc.); X1 and X2 are bound either directly or via an organic group to each other, the molar ratio X1 /X2 being (1:0.25) to (1:9); and (m)>=1, (n)>=1 and (m+n)>=2 ((m) and (n) are the numbers of X1 and X2 in the molecule, respectively} and (B) a liquid elastomer bearing functional group reactive with the phenolic OH group formed by ring opening for the component A and the dihydrobenzoxazine ring.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to heat which is preferably used as a raw material for high-performance molding materials, paints, coating materials, adhesives, encapsulating materials, laminates, FRP, etc., which are excellent in heat resistance and flame retardancy. A curable resin composition 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 because of their heat resistance and reliability due to their thermosetting properties. It is 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. Actually, it was necessary to appropriately compromise the problems depending on the application. Therefore, development of a novel thermosetting resin that does not have these problems has been promoted.

One of them is a dihydrobenzoxazine compound (JP-A-49-47387, US Pat. No. 5,152,939). The cure of this compound is
Since it utilizes the ring-opening polymerization reaction of the dihydrobenzoxazine ring, it is heat-cured with almost no generation of volatile components.

[0004]

A cured product obtained by curing a dihydrobenzoxazine compound utilizing this ring-opening polymerization reaction has good heat resistance as compared with conventionally known thermosetting resins, and High strength and excellent flexibility. However, compared with the thermoplastic resin, the toughness is relatively weak, such as the strength being high but the bending rate being small.

It is an object of the present invention to provide a thermosetting resin composition having a dihydrobenzoxazine ring, which has high strength and excellent toughness.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies to achieve the above object, the inventors of the present invention have found that dihydrobenzoxene can be prepared by blending a specific elastomer with a thermosetting resin having a dihydrobenzoxazine ring. It was found that the toughness can be improved more than the thermosetting resin having an oxazine ring alone, and other properties are not deteriorated,
Based on this finding, the present invention has been completed.

That is, the present invention relates to a thermosetting resin having a dihydrobenzoxazine ring, a thermosetting resin having a dihydrobenzoxazine ring, and a functional group capable of reacting with a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. The present invention provides a thermosetting resin composition characterized by containing a liquid elastomer having:

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A thermosetting resin having a dihydrobenzoxazine ring, a thermosetting resin having a dihydrobenzoxazine ring, and a functional group capable of reacting with a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring are formed. The blending ratio with the elastomer has 70 to 99% by weight of a thermosetting resin having a dihydrobenzoxazine ring, a thermosetting resin having a dihydrobenzoxazine ring, and a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. Elastomer having functional groups capable of
Preferably, it is 30% by weight.

When the proportion of the elastomer is less than 1% by weight, it becomes difficult to improve the toughness, so that 30% by weight is obtained.
If it exceeds, mechanical properties may be significantly reduced. That is, by setting the blending ratio of the elastomer to 1 to 30% by weight, more preferably 2 to 25% by weight, the toughness can be improved without deteriorating various characteristics such as mechanical characteristics.

As the dispersed state of the elastomer, a sea-island structure finely dispersed in a thermosetting resin having a dihydrobenzoxazine ring and an interpenetrating polymer network structure (IPN structure) with the thermosetting resin are preferable.

The thermosetting resin having a dihydrobenzoxazine ring is not particularly limited as long as it has a dihydrobenzoxazine ring and is cured by a ring-opening polymerization reaction of the dihydrobenzoxazine ring. Specifically, a polyhydric phenol, a compound having two or more hydroxyphenyl groups or hydroxyphenylene groups in which at least one ortho-position of a hydroxyl group is hydrogen in one molecule (hereinafter referred to as a polyfunctional phenol compound), The mixture with the primary amine is added to formaldehyde such as formalin heated to 70 ° C. or higher to 70 to 110 ° C.,
Preferably, it is obtained by reacting at 90 to 100 ° C. for 20 minutes to 2 hours and then drying under reduced pressure at a temperature of 120 ° C. or less.

Examples of polyfunctional phenol compounds include catechol, hydroquinone, resorcinol, bis (2-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, 4,4'-dihydroxydiphenylsulfone, 1,1-bis (4 -Hydroxyphenyl) ethane,
p, p'-isopropylidenebiphenol, 2,2-bis [4- (4'-hydroxyphenoxy) phenyl] propane, tris (4-hydroxyphenyl) methane,
Examples thereof include 1,1,1-tris (4-hydroxyphenyl) ethane, phenol novolak resin, resol resin, phenol-modified xylene resin, alkylphenol resin, melamine phenol resin, and phenol-modified polybutadiene. These are not particularly limited, but those in which the ortho position of the hydroxyl group serving as a crosslinking point is unsubstituted are desirable in terms of curing properties.For example, in the case of a phenol novolak resin, the ortho ratio is small and the molecular weight is relatively small. It is preferred to use small so-called random novolaks.

Specific examples of primary amines include substituted anilines such as methylamine, aniline, toluidine and anisidine. When it is an aliphatic amine, the obtained thermosetting resin cures quickly but has poor heat resistance. When an aromatic amine such as aniline is used, the cured product obtained by curing the obtained thermosetting resin has good heat resistance, but cures slowly.

Among the thermosetting resins having a dihydrobenzoxazine ring, preferably, the structural unit (A) represented by the following formula (A) and the structural unit represented by the following formula (B) in one molecule (B), wherein each structural unit is bonded directly or via an organic group, the molar ratio of (A) / (B) is 1 / 0.25 to 1/9, and 1 molecule When the number of structural units (A) is m and the number of structural units (B) is n,
A thermosetting resin having m ≧ 1, n ≧ 1 and 10 ≧ m + n ≧ 2 is used.

[0015]

Embedded image (Wherein R ¹ is a methyl group, a cyclohexyl group, a phenyl group, or a phenyl group substituted with at least one alkyl group or alkoxyl group having 1 to 3 carbon atoms,
Hydrogen in the aromatic ring of (A) and (B), except for one of the ortho positions of the hydroxyl group of (A), may be substituted with an alkyl group or alkoxyl group having 1 to 3 carbon atoms or a halogen atom. M and n are within the above ranges, and the structural units (A) and (B)
If the spaces are previously bound by a stable bond via a group having an appropriate chain length, the properties of the cured product will be good.

The structural unit (A) and the structural unit (B) are bonded directly or via an organic group. Examples of the organic group include an alkylene group and a divalent aromatic group. Examples of the alkylene group include a long-chain alkylene group having 5 or more carbon atoms, -CR ² H- (wherein R ² is a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a phenyl group or a substituted phenyl group. An alkylidene group represented by the formula: Examples of the substituent of the substituted phenyl group include a methyl group, a methoxy group, and a carboxyl group. Also,
As the divalent aromatic group, a phenylene group, a xylylene group,
And a tolylene group. Two or more of the above organic groups may be inserted between each structural unit.

The thermosetting resin of the present invention comprises (A) / (B)
Is preferably 1 / 0.25 to 1/9, more preferably 1 / 0.67 to 1/9. Outside this range, curability, mechanical strength, and heat resistance may decrease.

The above-mentioned thermosetting resin having a dihydrobenzoxazine ring is a compound having two or more hydroxyphenylene groups in which at least one ortho-position of a hydroxyl group is hydrogen in one molecule (hereinafter referred to as reactable hydroxyphenylene group). A compound having a group) and a primary amine are added to formaldehyde such as formalin heated to 70 ° C. or higher, and the mixture is heated at 70 to 110 ° C., preferably 90 to 100 ° C. for 20 minutes. It is obtained by reacting for ˜2 hours and then drying under reduced pressure at a temperature of 120 ° C. or lower. In this reaction, the primary amine is used in an amount of 0.2 to 0.9 mol and the formaldehydes are used in a ratio of at least twice the molar amount of the primary amine with respect to 1 mol of the hydroxyl group of the compound having a reactive hydroxyphenylene group. It is essential.

As the compound having a reactive hydroxyphenylene group, various compounds partially having a phenol nucleus can be used. Specific examples thereof include phenol novolac resin, resol resin, phenol-modified xylene resin, alkylphenol resin, melamine phenol resin, and phenol-modified polybutadiene.

The thermosetting resin having this dihydrobenzoxazine ring has a temperature of 150 ° C. or higher, preferably 170-2.
By heating to 20 ° C., curing is performed without using a catalyst or a curing agent and without generating by-products.

The thermosetting resin having a dihydrobenzoxazine ring used in the present invention can be used in combination of two or more kinds. In addition, by preliminarily treating these thermosetting resins at 80 to 180 ° C., preferably 120 to 160 ° C., a part of them can be pre-polymerized to control the curing rate and melt viscosity during molding.

In the present invention, the liquid elastomer blended with the thermosetting resin having a dihydrobenzoxazine ring includes a thermosetting resin having a dihydrobenzoxazine ring and a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. A liquid elastomer having a functional group capable of reacting with is used.

The type of elastomer is not particularly limited as long as it is a thermosetting resin having a dihydrobenzoxazine ring and a liquid elastomer having a functional group capable of reacting with a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. , Acrylic and butadiene elastomers are preferably used. These elastomers include homopolymers composed of one type of monomer, 2
Examples thereof include block copolymers, graft copolymers, random copolymers, and mixtures thereof, which are composed of at least one kind of monomer. Particularly preferably, liquid acrylonitrile-butadiene copolymer elastomer and liquid polybutadiene are used.

The thermosetting resin having a dihydrobenzoxazine ring and the functional group capable of reacting with the phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring include an amino group, an epoxy group, a carboxyl group and a phenolic hydroxyl group. Is mentioned.

The above-mentioned elastomer is preliminarily prepared before the thermosetting resin having a dihydrobenzoxazine ring is cured.
A part thereof may be prepolymerized at ˜180 ° C., preferably 80 to 160 ° C.

Further, if necessary, a compound having a phenolic hydroxyl group in a structural unit such as phenol novolac resin and a curing agent for phenol resin such as hexamethylenetetramine or calcium hydroxide may be added as a curing agent. it can. The preferable mixing ratio of these is 1 to 35 parts by weight with respect to 100 parts by weight of the thermosetting resin.

The thermosetting resin having a dihydrobenzoxazine ring and the elastomer may be dissolved in a solvent and mixed, but it is preferable that the thermosetting resin and the elastomer are melt-mixed with a heating roll or the like.

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

The thermosetting resin composition of the present invention is kneaded by a heating roll or the like, and thereafter, the temperature is 180 to 220 ° C. and the molding pressure is 2
By performing compression molding or transfer molding at 0 to 70 kgf / cm ² for 3 to 10 minutes and curing, the toughness is improved as compared with a thermosetting resin having a dihydrobenzoxazine ring alone,
Further, a cured product having good mechanical properties and flame retardancy can be obtained.

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.

[0031]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples of the present invention and Comparative Examples thereof, but the present invention is not limited to these Examples.

Examples 1 to 8 and Comparative Examples 1 to 5 Synthesis of thermosetting resin having dihydrobenzoxazine ring (I) (1) Synthesis of phenol novolac resin 1.9 kg of phenol, formalin (37% aqueous solution)
1.15 kg and 4 g of oxalic acid were charged in a 5 liter flask and reacted at reflux temperature for 6 hours. Subsequently, the internal pressure was reduced to 6666.1 Pa or less to remove unreacted phenol and water. The obtained resin had a softening point of 89 ° C. (ring and ball method) and a 3 to polynuclear / binuclear ratio of 89/11 (peak area ratio by gel permeation chromatography).

(2) Introduction of dihydrobenzoxazine ring 1.7 k of phenol novolac resin synthesized as described above
g (equivalent to 16 mol of hydroxyl groups) to aniline 0.9
The mixture was mixed with 8 kg (corresponding to 11 mol) and stirred at 80 ° C. for 5 hours to prepare a uniform mixed solution. In a 5 liter flask, 1.62 kg of formalin was charged and heated to 90 ° C.
The novolak / aniline mixed solution was gradually added thereto over 30 minutes. After the addition was completed, the temperature was maintained at reflux temperature for 30 minutes, and after that, the condensation water was removed by reducing the pressure to 6666.1 Pa or less at 100 ° C. for 2 hours to remove the heat by which 75% of the reactive hydroxyl groups were dihydrobenzoxazinated. A curable resin was obtained (m = 1, n = 2.2).

Synthesis of thermosetting resin having dihydrobenzoxazine ring (II) (1) Synthesis of phenol novolac resin Phenol 1.9 kg, formalin (37% aqueous solution)
1.0 kg and 4 g of oxalic acid were charged into a 5 liter flask, and a phenol novolac resin was synthesized in the same manner as in the synthesis (I) of thermosetting resin having a dihydrobenzoxazine ring. The obtained resin has a softening point of 84 ° C. (ring and ball method), 3
The polynuclear body / binuclear body ratio was 82/18 (peak area ratio by gel permeation chromatography).

(2) Introduction of dihydrobenzoxazine ring Hereinafter, the dihydrobenzoxazine ring was introduced in the same manner as in the synthesis (I) of the thermosetting resin having a dihydrobenzoxazine ring. The resulting thermosetting resin was a phenol novolac resin in which a dihydrobenzoxazine ring was introduced into 71% of the reactive hydroxyl groups (m = 3, n = 5).

Synthesis of Thermosetting Resin Having Dihydrobenzoxazine Ring (III) 1.70 kg of xylylene-modified phenol resin (trade name Milex XL-225-3L manufactured by Mitsui Toatsu Chemicals, Inc.)
(Corresponding to 10 mol of hydroxyl group), aniline 0.52
kg (5.6 mol), formalin (37% aqueous solution)
A thermosetting resin in which a dihydrobenzoxazine ring was introduced into 71% of hydroxyl groups capable of reacting in the same manner as in the above synthetic method was synthesized with the addition of 0.91 kg (m = 2.2, n =
2.8).

Synthesis of dimethylene ether type resole resin 2 kg phenol resin, formalin (37% aqueous solution)
0.35 kg, 0.78 kg of paraformaldehyde and 9.3 g of zinc acetate were charged in a 5 liter flask and reacted at a reflux temperature for 6 hours. 6666.1P inside
The pressure was reduced to a or less, and unreacted phenol and water were removed by steam distillation. The obtained resin had a softening point of 77 ° C.

As the elastomer, liquid acrylonitrile-polybutadiene copolymer (1) (trade name: CTBN1300X31 manufactured by Ube Industries, Ltd., AN amount 27.0% by weight, carboxyl group amount 2.47% by weight), liquid acrylonitrile-polybutadiene copolymer Polymer (2) (trade name: ATBN1300X16, manufactured by Ube Industries, Ltd., AN amount: 1)
6.5 wt%, amino group-containing, amine equivalent 900), liquid polybutadiene (trade name Denarex R-45 EPI, manufactured by Idemitsu Atchem Co., Ltd., epoxy equivalent 200, epoxy group-containing) was used.

The thermosetting resin and the elastomer are 80 to 10
Using a biaxial kneading roll heated to 0 ° C., kneading was continued for 3 minutes until uniform.

The resin composition mixed as described above is crushed,
180 in the mold with an inner diameter of 120 x 80 x 15 mm
A cured product was produced by heating and pressurizing at 1.96 MPa for 10 minutes.

The characteristics of the cured product are Charpy impact strength, flexural strength and flexural modulus according to JIS K6911.
Evaluation was made at a temperature of 2 ° C. and a bending speed of 2 mm / min.

Regarding flame retardancy, according to UL-94, 3.
Evaluation was made with a thickness of 6 mm.

The blending composition (parts by weight) and the measurement results are shown in Tables 1 to 5 below.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

The thermosetting resin composition of the present invention has high toughness, and the cured product has good mechanical properties and flame retardancy. Therefore, the thermosetting resin composition of the present invention is a highly functional molding material, paint, coating agent, adhesive, sealant,
It is useful as a raw material for laminated plates and FRP.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI technical display location C08L 21:00) (72) Inventor Hideo Nagase 1500 Ogawa, Shimodate-shi, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Factory (72) Inventor Shunichi Numata 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd.Shimodate Factory (72) Inventor Yukio Yoshimura 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Factory

Claims (4)

[Claims] 1. A thermosetting resin having a dihydrobenzoxazine ring, a thermosetting resin having a dihydrobenzoxazine ring, and a liquid having a functional group capable of reacting with a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. A thermosetting resin composition comprising an elastomer. 2. A thermosetting resin having a dihydrobenzoxazine ring reacts with 70 to 99% by weight and a thermosetting resin having a dihydrobenzoxazine ring and a phenolic hydroxyl group formed by ring opening of the dihydrobenzoxazine ring. 1 to 30% by weight of an elastomer having a functional group to be obtained
The thermosetting resin composition according to claim 1, which is 3. A thermosetting resin having a dihydrobenzoxazine ring contains a structural unit (A) represented by the following formula (A) and a structural unit (B) represented by the following formula (B) in one molecule. And each structural unit is bonded directly or via an organic group, and the molar ratio of (A) / (B) is 1 / 0.25 to 1 /
9 and m is the number of structural units (A) and n is the number of structural units (B) in one molecule, m ≧ 1, n ≧ 1 and 10
A thermosetting resin satisfying ≧ m + n ≧ 2.
The thermosetting resin composition according to the above. Embedded image (Wherein R ¹ is a methyl group, a cyclohexyl group, a phenyl group, or a phenyl group substituted with at least one alkyl group or alkoxyl group having 1 to 3 carbon atoms,
Hydrogen in the aromatic ring of (A) and (B), except for one of the ortho positions of the hydroxyl group of (A), may be substituted with an alkyl group or alkoxyl group having 1 to 3 carbon atoms or a halogen atom. ) 4. A cured product obtained by curing the thermosetting resin composition according to claim 1.