JPH1017636A - Flame-retardant thermosetting resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition giving less load on the environment and having high flame retardancy. SOLUTION: This composition essentially consists of a compound represented by formula 1: X-R1 -X (wherein X is a functional group reactive with functional group Y of a compound represented by formula 2, and R1 is a crystalline functional group containing a phenyl) and a novolak compound represented by formula 2 (wherein Y is a functional group reactive with functional group X of a compound represented by formula 1; R2 is a functional group reactive with functional group X, hydrogen or a 1-5 C hydrocarbon group; and n is an integer of 0-20). The mixing ratio of the compounds represented by formulas 1 and 2 is desirably such that the total amount of functional groups Y and functional groups R2 reactive with functional groups X in the compound represented by formula 2 is excess over the number of chemical equivalents of functional groups X and is in the range in which a curing reaction can take place.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosetting resin composition having a low environmental load and a high flame retardancy.

[0002]

2. Description of the Related Art Thermosetting resins are widely used as electric insulating materials and building materials because of their good insulating properties, heat resistance and strength. In many applications, a flame retardant is added.

As the flame retardant, compounds containing halogen such as bromine and chlorine and compounds containing phosphorus are widely used. However, in the former case, highly toxic halogen-based gases are generated when resin products containing these are fired or incinerated after disposal, and in the latter case, toxic gases are generated when resin products containing these are burned. Although difficult to do, harmful phosphorus compounds tend to elute when discarded and landfilled, and all have the problem of having a large environmental load.

On the other hand, hydrates of inorganic substances having a low environmental load such as hydrates of aluminum hydroxide are known to have a flame-retardant effect.
Not universal because of adverse effects on moldability and other properties.

[0005] In view of the above, it is conceivable to improve the flame retardancy of the resin itself by examining the crosslinked structure of the thermosetting resin composition as flame retardant with low environmental load. It is considered that normal plastics combustion proceeds when the plastics is thermally decomposed to generate flammable decomposed products, which are ignited (Ichita Eita, plastics flame retardant, June 1978). Month 26
Nikkan Kogyo Shimbun, p. 39-41). In the case of thermosetting resins, those containing aromatics in the structure and those having a higher crosslink density have higher residual ratios (residual carbon ratio) during heating and higher thermal decomposition resistance, that is, higher heat resistance. (Masaki Shinbo, Handbook of Epoxy Resins, 198
(December 25, 2007, P368-369, Nikkan Kogyo Shimbun).

Therefore, in the past, in order to improve the flame retardancy, it has been the main means to improve such heat resistance, and the combination of the main resin to be thermally cured and the curing agent is aromatic. Select the one that contains the tribe,
By blending the reactive functional groups of the main resin and the curing agent in chemical equivalents, that is, in a ratio of 1: 1 so that a 1: 1 reaction occurs, crosslinking is performed using the glass transition temperature of the cured product as an index. It was customary to maximize the density.

[0007] However, even when aromatics are used, and the resin and the curing agent are mixed in equivalent amounts to increase the crosslink density and improve the heat resistance, the flame retardancy is often insufficient. For example, among the thermosetting resins, the flame retardancy is a combination of a cresol novolak type epoxy resin and a phenol novolak curing agent, which are aromatic, and have one of the highest heat resistance and a high glass transition temperature. Insufficient, usually containing a bromine compound as a flame retardant (Hiroshi Miyasaka, Encyclopedia of Plastics, March 1, 1992
Sun, page 273, described in Asakura Shoten).

[0008] The flame retardancy of the resin is, according to the prescribed evaluation method, self-extinguishing property after ignition (combustion test method according to UL94) or the amount of oxygen necessary for burning (JIS-K-
It is considered that the evaluation by the oxygen index method according to 7201) greatly affects not only the heat resistance of the resin but also other factors such as the formability of a noncombustible structure represented by graphite.

On the other hand, a combination of an epoxy resin containing a crystalline biphenyl group or a naphthalene group in the structure of a thermosetting resin composition and a phenol novolak resin as a curing agent has already been studied. The only effect of the combination is known to improve the crack resistance of a molded article such as an IC package (Japanese Patent Application Laid-Open Nos. 61-47725 and 3-112417). In particular, the relationship between the crosslinked structure and the flame retardancy was not known.

[0010]

As described above, halogen and phosphorus-based flame retardants conventionally used for improving the flame retardancy of a thermosetting resin have a problem that the environmental load is large as described above.

In the case where the flame retardancy of the resin itself is to be improved without adding a flame retardant, improvement of heat resistance (thermal decomposition resistance) has conventionally been the solution to this problem. Effects have not been obtained.

Accordingly, an object of the present invention is to provide a thermosetting resin having a structure that improves the flame retardancy itself.

[0013]

In order to solve the above-mentioned problems, the present invention is a thermosetting resin composition comprising a compound represented by the formula 1 and a novolak compound represented by the formula 2 as essential components. .

[0014]

Embedded image

Here, the phenyl group-containing crystalline functional group R _{1 of the} compound represented by the formula 1 contains a phenyl group, and is characterized in that it is arranged with regularity and easily oriented. That is, a highly crystalline functional group,
Specifically, biphenyl, 3,3 ', 5,5'-tetramethylbiphenyl, naphthalene, 2,2-diphenylpropane, biphenyl ether, diphenylmethane, diphenylsulfone, diaminodiphenylmethane and analogs thereof are particularly preferable. Is that biphenyl, naphthalene, 2,2-diphenylpropane, diphenylmethane and their analogs are effective for improving flame retardancy.

A polymer obtained by addition polymerization or polycondensation of R ₁ may be mixed with a part of the compound of the formula 1. In this case, the degree of polymerization of these polymers is preferably 5 or less. The proportion of the polymer is 60% by weight of the whole compound of the formula 1.
The following values are preferable, and when these values are exceeded, the improvement in flame retardancy may decrease. Specific examples of the polymerization mode include those obtained by polymerizing a compound 1 in which X is an epoxy group and a compound in which X is a hydroxyl group.

Further, the functional group X of the compound represented by the formula (1)
And a functional group R ₂ capable of reacting with the functional groups Y and X of the compound represented by the formula 2 can be reacted at a temperature under normal molding conditions or a post-curing temperature, that is, from room temperature to about 200 ° C. In particular, when one of X and Y is a functional group containing an epoxy group, the crosslinking reaction rate is appropriate, so that a highly flame-retardant crosslinked structure can be easily formed under ordinary molding conditions. .

Examples of the functional group containing an epoxy group include glycidyl, glycidoxy, glycidylamine, and alicyclic epoxy. Examples of a functional group to be combined with a functional group containing an epoxy group include a hydroxyl group, an amino group, and a carboxyl group. Among them, the combination of X is a glycidoxy group and Y and R ₂ are hydroxyl groups is not only in view of flame retardancy, but also from the viewpoint of easiness of kneading and molding, moisture resistance and electric properties of the cured product after the crosslinking reaction. preferable.

The functional group R ₂ in the novolaks represented by the formula 2 is a functional group capable of reacting with X, a hydrocarbon having 1 to 5 carbon atoms, or hydrogen. In the structure of the novolaks of the formula 2, phenyl groups to which Y is not added may be mixed. In this case, the proportion of phenyl groups without Y is 50% by weight or less of the whole phenyl groups. It is preferable from the viewpoint of properties. In addition, n in the formula 2 is suitably from 1 to 20, and if it is more than this, the viscosity at the time of kneading is too high, and uniform mixing with other materials or moldability may be impaired. Further, novolaks having n in this range may be mixed.

As a preferred specific example of the compounds of the formulas 1 and 2, the compound of the formula 1 is 3,3 ', 5,5'-tetramethylbiphenyl-4,4'-diglycidyl ether, biphenyl-4, 4'-diglycidyl ether, naphthalene-1,6-diglycidyl ether, bisphenol A
And the diglycidyl ether of bisphenol F. These can be mixed and used. In the compound of formula 2, Y is a hydroxyl group, and R ₂ is a phenol novolak of a hydroxyl group, hydrogen, or hydrocarbon. Specifically, a phenol novolak resin, a cresol novolak resin, a catechol novolak resin, a naphthol novolak Resins, phenol-xylene diol novolak, catechol-xylene diol novolak, and the like. Among them, particularly when catechol novolak resin is used, or when used in combination with another, the glass transition temperature of the cured product of the resin composition is improved as compared with other novolaks. Is preferred.

Furthermore, in the present composition, the total amount of the functional group Y and the functional group R ₂ capable of reacting with the functional group X of the compound of the formula 1 in the novolaks of the compound of the formula 2 is The flame retardancy is greatly improved when the compound is blended in excess of the chemical equivalent to the functional group X. Specifically, the functional group Y and the functional group R of the compound of the formula 2
₂ is based on the amount of the functional group X of the compound of the formula 1,
When it is 1.1 times or more the chemical equivalent, it is particularly effective for flame retardancy.

However, if the total amount of Y and R ₂ is excessively large and the curing reaction becomes insufficient, the adverse effect on the flame retardancy is small, but the moldability such as mold release and curability, heat resistance and strength. Since other physical properties such as properties are adversely affected and hinder the use as the original thermosetting resin, Y and R ₂
Is within a range where a curing reaction can occur. For example, for the compound of formula 2, the upper limit of the excess is, in the case of phenol novolak, the hydroxyl group of phenol novolak is preferably not more than 3.0 times the chemical equivalent to X of compound 1, and in the case of catechol novolak, the hydroxyl group is preferably not more than 3.0 times. 3.
5 times or less is preferable. If the ratio exceeds these, it is difficult to cure during molding, and as a result, there are adverse effects on the moldability and the physical properties such as heat resistance and strength of the cured product.

The total amount of the compound of the formula 1 and the compound of the formula 2 is preferably at least 60% by weight of the resin component in the resin composition in order to improve the flame retardancy.

In the present composition, components added as needed include inorganic fillers such as silica powder, alumina powder and glass fiber; curing accelerators such as phosphorus compounds such as triphenylphosphine and various amine compounds; Release agents such as carnauba wax and stearates; surface treatment agents for inorganic fillers such as silane coupling agents; and coloring agents such as carbon.

These compositions can be produced by, if necessary, preliminarily mixing the constituent materials with a ribbon blender or a Henschel mixer, and then mixing them with a heating roll, kneader, batch mixer or the like. Then, by heating under a predetermined molding condition by a transfer molding machine or a hot press molding machine to cause a crosslinking reaction and to cure, a cured molded article having high flame retardancy can be obtained.

As described above, in the present composition, by blending the compound of the formula 2 in excess of the chemical equivalent of the compound of the formula 1, the crosslink density of the cured product is lowered, and the flame retardancy is lower when the heat resistance is lowered. Since the flame retardancy is improved, the flame retardancy is significantly affected by a factor different from the heat resistance, which is considered to be due to the formation of a highly flame-retardant crosslinked structure specific to the cured product of the present composition.

[0027]

Embodiments of the present invention will be described below with reference to examples.

(Examples 1 to 9) In this example, as a compound represented by formula 1, R ₁ is 3,3 ', 5,5'-tetramethylbiphenyl and X is glycidoxy.
3,3 ', 5,5'-tetramethylbiphenyl-4,
4'-Diglycidyl ether and a compound represented by the formula 1 as a mixture of 50% by weight of a biphenyl-4,4'-diglycidyl ether of the following formula 4 wherein R ₁ is biphenyl and X is glycidoxy ( Epoxy equivalent 17
0, 104 ° C. softening point, hereinafter referred to as epoxy resin A).

[0029]

Embedded image

In this example, as the compound represented by the formula 2, a phenol novolak resin represented by the following formula 5 wherein R ₂ is hydrogen and Y is a hydroxyl group (hydroxyl equivalent 106, softening point 80 ° C., Weight average molecular weight of 1200, hereinafter referred to as phenolic resin A).

[0031]

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The total of the epoxy resin A and the phenol resin A is 31.0% by weight, and other additives are 0.5% by weight of triphenylphosphine and 0.5% of carnauba wax.
% By weight and silica powder (fused silica having an average particle diameter of 25 microns) in a mixing ratio of 68.0% by weight, and then mixed with a Henschel mixer.
After kneading at ~ 110 ° C for 5 minutes and cooling with a cooling press,
The mixture was crushed in a mortar and passed through a 6-mesh sieve to prepare a molding material.

Here, epoxy resin A and phenol resin A
Of the glycidoxy group (functional group X) of the epoxy resin A and the hydroxyl group (functional group Y) of the phenol resin A in equivalent ratio (functional group This is the equivalent ratio of the functional group Y to X, and is assumed to be y / x).

Using this molding material, molding was performed at 175 ° C. for 6 minutes using a transfer molding machine. Table 1 shows the results of the mold releasability from the mold and the curability (hardness) of the molded body as an index of the moldability at this time.

The molded body was further heated at 175 ° C. for 6 hours for post-curing, and then cut into a predetermined size to prepare a test piece. The flame retardancy of this test piece was evaluated by the oxygen index method (JIS-K-7201), and the glass transition temperature was measured by thermomechanical analysis (TMA) (sample length: 10 to 11 mm, atmosphere: air). Medium, heating rate; 5 ° C
/ Min, load; 2 g, temperature range; room temperature to 300 ° C). These results are also shown in Table 1.

FIG. 1 particularly shows the results of the oxygen index. Here, the higher the oxygen index, the better the flame retardancy. As can be seen from the results, the flame retardancy is particularly improved in a range where the resin can be cured when y / x is 1.1 or more.

[0037]

[Table 1]

(Examples 10 to 19) As the compound represented by the formula 1, the same epoxy resin A as that used in Examples 1 to 9, and as the compound represented by the formula 2, Y is a hydroxyl group,
R ₂ is a catechol novolak resin of the following formula 6 having a hydroxyl group (hydroxyl equivalent: 61, softening point: 107 ° C., weight average molecular weight: 9)
90, hereinafter referred to as phenolic resin B), in the proportions shown in Table 2, together with the same additives as in Examples 1 to 9, in the same manner as in Examples 1 to 9, and kneaded. Was evaluated. At this time, the total content of these resins in the composition,
The contents of other additives are the same as in Examples 1 to 9.

Here, the equivalent ratio of the total amount of the hydroxyl groups of the functional groups Y and R _{2 to} the amount of the glycidoxy groups of the functional group X is represented by y.
/ X.

[0040]

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Table 2 shows the results of these oxygen indices and glass transition temperatures. FIG. 2 particularly shows the results of the oxygen index.
As can be seen from the results, the flame retardancy is particularly improved in the range where the curing is possible when y / x is 1.1 or more.

[0042]

[Table 2]

(Examples 20 to 28) As a compound represented by the formula 1, R ₁ is 2,2-diphenylpropane;
It consists of a diglycidyl ether of bisphenol A represented by the following formula 7, wherein X is glycidoxy, and a dimer polymer represented by the above formula 7 represented by the formula 8, and their ratio by weight is 87:13. Such a mixture (epoxy equivalent 189, viscosity 140 poise (room temperature), hereinafter referred to as epoxy resin B) and the phenol resin A as a compound represented by the formula 2 were further added in the proportions shown in Table 3 to Examples 1 to 9.
100 to 11 on a heated roll, with additives similar to
After kneading at 0 ° C. for 5 minutes, molding and evaluation were performed in the same manner as in Examples 1 to 9. At this time, the total content of these resins in the composition and the content of other additives are the same as in Examples 1 to 9.

[0044]

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The results of the oxygen index and the glass transition temperature are shown in Table 3. FIG. 3 particularly shows the results of the oxygen index.
As can be seen from these results, the equivalent ratio (y / x) of the amount of the hydroxyl group of the phenolic resin A to the amount of the glycidoxy group of the epoxy resin B is 1.1 or more. improves.

[0046]

[Table 3]

(Examples 29 to 37) As a compound represented by the formula 1, naphthalene-1,6-diglycidyl ether represented by the following formula 9 wherein R ₁ is naphthalene and X is glycidoxy (epoxy equivalent: 152) , Hereinafter referred to as epoxy resin C) and phenolic resin A as a compound represented by formula 2 in the proportions shown in Table 4 in Examples 1-9.
100 to 11 on a heated roll, with additives similar to
After kneading at 0 ° C. for 5 minutes, molding and evaluation were performed in the same manner as in Examples 1 to 9. At this time, the total content of these resins in the composition and the content of other additives are the same as in Examples 1 to 9.

[0048]

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The results of the oxygen index and the glass transition temperature are shown in Table 4. FIG. 4 particularly shows the results of the oxygen index.
As can be seen from the results, the equivalent ratio (y / x) of the amount of the hydroxyl group of the phenolic resin A to the amount of the glycidoxy group of the epoxy resin C is 1.1 or more, and as long as the resin can be cured,
In particular, the flame retardancy is improved.

[0050]

[Table 4]

(Comparative Examples 1 to 9) As comparative examples of the present invention,
As a comparison of the compound of the formula 1, an ortho-cresol represented by the following formula 10 having a structure in which a non-crystalline cresol novolak is used in place of the crystalline R ₁ of the formula 1 and further a glycidoxy is attached as a functional group X thereto. A novolak type epoxy resin (epoxy equivalent: 194, softening point: 80 ° C., weight average molecular weight: 2900, hereinafter referred to as epoxy resin D);
Formula 5 used in the examples as the described novolak compound
Was mixed and kneaded with the same additives as in Examples 1 to 9 at the ratios shown in Table 5, and molded and evaluated. At this time, the total content of these resins in the composition and the content of other additives are the same as in Examples 1 to 9.

[0052]

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Table 5 shows the results of the oxygen index and the glass transition temperature. In particular, the results of these oxygen indexes are shown in FIG.
Shown in As can be seen from these results, as compared with the resin compositions of the examples, the glass transition temperature is generally higher, but the flame retardancy is significantly inferior, and the hydroxyl groups of the phenol resin A relative to the glycidoxy groups of the epoxy resin D are further reduced. No effect on the flame retardancy of the equivalent ratio (y / x) of the amounts is observed.

[0054]

[Table 5]

As described above, as shown in Examples 1 to 37, the combination system of the crystalline epoxy resin of the compound of the formula 1 of the present invention and the phenolic resin of the novolak of the formula 2 is the same as the glass shown in the comparative example. It can be seen that it exhibits higher flame retardancy than a combination system of a non-crystalline ortho-cresol novolac epoxy resin and a phenol resin, which has a high transition temperature and good heat resistance.

Further, the phenolic resin of the formula 2 is
It can be seen that when the epoxy resin is blended in excess of the chemical equivalent, that is, when the equivalent ratio (y / x) of the amount of hydroxyl group to the amount of glycidoxy is 1.1 or more, particularly good flame retardancy is exhibited. However, in the case of an excessive excess, for example, in the case of phenol novolak, if the chemical equivalent is 3.0 times, and in the case of catechol novolak, more than 3.5 times, it does not affect the flame retardancy, but it does not affect the releasability or curing. In addition, the moldability typified by the moldability is reduced, and the glass transition temperature is extremely lowered, so that the heat resistance is lowered.

[0057]

The effect of the present invention is to provide a thermosetting resin composition having high flame retardancy itself without adding a conventional flame retardant having a large environmental load.

[Brief description of the drawings]

FIG. 1 is a view showing the results of oxygen index analysis of molded articles according to the present invention (Examples 1 to 9).

FIG. 2 is a view showing the results of oxygen index analysis of molded articles according to the present invention (Examples 10 to 19).

FIG. 3 is a view showing the results of oxygen index analysis of molded articles according to the present invention (Examples 20 to 28).

FIG. 4 is a view showing the results of oxygen index analysis of molded articles according to the present invention (Examples 29 to 37).

FIG. 5 is a view showing the results of oxygen index analysis of the molded products described in Comparative Examples 1 to 9.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08K 3/22 C08K 3/22

Claims (4)

[Claims] 1. A compound of the general formula XR ₁ -X (formula 1) wherein X is a functional group capable of reacting with the functional group Y of the compound of formula 2, and R ₁ is a crystalline functional group containing a phenyl group. A thermosetting resin composition comprising, as essential components, a compound represented by formula (I) and a novolak compound represented by formula (2). Embedded image (Y is a functional group capable of reacting with the functional group X of the compound of Formula 1; R ₂ is a functional group capable of reacting with the functional group X of the compound of Formula 1, or a hydrocarbon having 1 to 3 carbon atoms, or hydrogen. And n is an integer from 1 to 20). 2. The compound according to claim 1, wherein R ₁ containing the phenyl group is any _one of biphenyl, naphthalene, biphenyl ether, 2,2-diphenylpropane, diphenylmethane and analogs thereof. The thermosetting resin composition according to claim 1, wherein: 3. The compound according to claim 1, wherein at least one of the functional group X of the compound represented by the formula 1 and the functional group Y of the compound represented by the formula 2 is a functional group containing an epoxy group. Or the thermosetting resin composition according to claim 2. 4. The compound according to claim 2, wherein the functional group R is capable of reacting with the functional group Y and the functional group X of the formula 1.
The total amount of _2, relative to the amount of the functional group X of the aforementioned compound 1, excess than the chemical equivalent of Y and R ₂ is reacted with X, to be the range up may occur curing reaction The thermosetting resin composition according to claim 1, wherein the compound is a compounding ratio of the compounds of the formulas 1 and 2.