JPS6234917A - Hardener for epoxy resin - Google Patents

Abstract

PURPOSE:To provide the titled hardener giving a cured material having excellent heat-resistance and high glass-transition point and suitable as an adhesive and sealing material, by hydrogenating a polymerization product of a cyclopentadiene monomer and an unsaturated dicarboxylic acid (anhydride). CONSTITUTION:The objective hardener can be produced by polymerizing (A) 90-30wt% cyclopentadiene monomer and (B) 10-70wt% unsaturated dicarboxylic acid (anhydride) (e.g. maleic acid) to obtain a polymerization product preferably having a softening point of 60-200 deg.C and a bromine value of 10-200g/100g, and hydrogenating the polymer in the presence of a hydrogenation catalyst (e.g. nickel catalyst) in a solvent (e.g. tetrahydrofuran). A cured material having excellent thermal characteristics can be produced by adding 50-200pts. wt. of the hardener to 100pts.wt. of uncured epoxy resin and curing the mixture at 100-200 deg.C.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a curing agent for epoxy resin, and more specifically, it provides a cured epoxy resin having improved heat resistance and a high glass transition point. This invention relates to a curing agent for epoxy resin.

[Prior art and its problems] Various compounds have been known as curing agents for epoxy resins, but maleic anhydride has been widely used as a curing agent because relatively mild conditions can be adopted. Acids and phthalic anhydride are known.

However, since the epoxy resin cured products obtained using these curing agents have a glass transition point as low as 120 to 170°C, the uses of the epoxy resin are often limited.

Furthermore, pyromellitic anhydride is known as a curing agent used for the purpose of obtaining a cured epoxy resin having a high glass transition point.

However, this pyromellitic anhydride has a melting point of 28
It is as high as 6℃, which is higher than the normal curing temperature of epoxy resin (170℃
The compatibility between unmelted pyromellitic anhydride and uncured epoxy resin is extremely poor, and the current situation is that it is hardly used in practice. For this reason, attempts have been made to mix maleic anhydride or phthalic anhydride with this pyromellitic anhydride to form a curing agent.

However, in order to harmonize the melting point of the curing agent and the curing temperature of the epoxy resin, a complicated mixing operation of the pyromellitic anhydride and the maleic anhydride or phthalic anhydride is required, and the mixture is not necessarily uniform. is not necessarily obtained. Furthermore, since pyromellitic anhydride has extremely high hygroscopicity, more care than expected must be taken in the production and handling of a curing agent containing pyromellitic anhydride.

In order to solve the above problems, the applicant has already developed a curing agent for epoxy resins having a reaction product obtained by the polymerization reaction of dicyclopentadiene and maleic anhydride as having a high glass transition point. is suggesting.

However, the applicant has discovered a new problem in that the proposed curing agent for epoxy resins does not yet have sufficient heat resistance.

This invention was made based on the above circumstances,
A cured epoxy resin having a glass transition point exceeding 200° C. and improved heat resistance can be obtained and easily manufactured. The purpose of the present invention is to provide a curing agent for epoxy resin that is easy to handle.

[Means for solving the above problems] In order to solve the above problems, the present inventors conducted intensive research and surprisingly found that hydrogenated compounds of known polymers can be used as curing agents for epoxy resins. suitable, and
The present invention was achieved by discovering that the polymer compound is easy to manufacture and handle.

The outline of this invention is hydrogenation of a polymerization product (hereinafter sometimes referred to as component (A)) obtained by a polymerization reaction of a cyclopentadiene monomer and an unsaturated dicarboxylic acid and/or its anhydride. (hereinafter sometimes referred to as component (B)).

The cyclopentadiene monomer and unsaturated dicarboxylic acid or anhydride thereof are known compounds,
Regarding this invention, there are no particular limitations on the two types of compounds. However, it is preferable that both dicyclopentadiene and maleic anhydride be sufficiently purified prior to the polymerization reaction.

If an unpurified cyclopentadiene monomer is subjected to a polymerization reaction with an unsaturated dicarboxylic acid or its anhydride, side reactions may occur and a suitable polymerization product may not be obtained.

Examples of the cyclopentadiene monomer include:
Cyclopentadiene, methylcyclopentadiene,
ethylcyclopentadiene or dimers thereof,
Examples include dimers, co-dimers, and petroleum cracking fractions containing these.

Examples of the unsaturated dicarboxylic acids include maleic acid, citraconic acid, and itaconic acid, and examples of the unsaturated dicarboxylic anhydrides include anhydrides of the various unsaturated dicarboxylic acids described above.

The component (A) is obtained by a known copolymerization reaction of the cyclopentadiene monomer and an unsaturated dicarboxylic acid and/or an anhydride thereof. This (A)
Although the component is obtained by a known polymerization reaction, there is still no established theory about its structure.
Although it is presumed to be a copolymer with carbonic acid and/or its anhydride, this component (A) contains cyclopentane. It is also possible that it contains homopolymers of gene monomers.

However, component (A) suitable as a raw material for the curing agent for epoxy resin of the present invention has a content of 1,000 units derived from a cyclopentadiene monomer of 90 to 30% by weight, preferably 80 to 40% by weight. % by weight, and the content of seven units derived from unsaturated dicarboxylic acid or its anhydride is 1
0 to 70% by weight, preferably 20 to 60% by weight,
It has a softening point of 60-200°C, preferably 90-180°C, a bromine number of io-200 g/100 g, preferably 50-130 g/100 g, and an acid value of 100
~500mgKOH/g, preferably 200-450
mgKOH/g.

In addition, a preferred component (A) from the viewpoint of raw material components is a polymerization product obtained by copolymerizing cyclopentadiene and maleic anhydride.

The polymerization reaction conditions for obtaining component (A) suitable as described above as a raw material for this curing agent for epoxy resin include, for example, a combination of a cyclopentadiene monomer and an unsaturated dicarboxylic acid and/or its anhydride. The heating temperature is 200~
320°C, preferably 250 to 300°C, and
The polymerization reaction time is 0.5 to 10 hours, preferably 1.5 hours.
~5 hours.

Note that a solvent is not necessarily required for the polymerization reaction;
When a solvent is required for controlling the reaction temperature, dispersing monomers, etc., benzene, toluene, xylene, etc. can be used, for example.

Moreover, this polymerization reaction does not particularly require a catalyst.

The curing agent for epoxy resins according to the present invention contains a hydrogenated product (component (B)) obtained by hydrogenating the component (A).

The above (B) component is usually added to the above (B) in the presence of a hydrogenation catalyst.
A) It can be produced by bringing component A) into contact with hydrogen while heating.

As the hydrogenation catalyst, for example, a nickel catalyst,
Examples include palladium catalysts, cobalt catalysts, platinum catalysts, and rhodium catalysts.

In addition, the heating temperature range during hydrogenation is usually 1
The temperature is 30-300°C, preferably 150-250°C.

The hydrogenation time is usually 1 to 7 hours, preferably 2 to 5 hours.
It takes about an hour.

In order to facilitate hydrogenation, a polar solvent such as tetrahydrofuran may be used.

The product obtained by the hydrogenation reaction can be used as it is as a curing agent for epoxy resins, or can be used with the addition of an appropriate solvent to adjust the viscosity.

This (B) component, as in the case of the polymerization component, consists of a cyclopentadiene monomer, an unsaturated dicarboxylic acid and/or
Alternatively, in addition to the hydrogenated copolymer with the anhydride thereof, there is a possibility that it contains a hydrogenated product of the homopolymer of the cyclopentadiene monomer.

In any case, in the present invention, preferred component (B) has a monomer unit content derived from a cyclopentadiene monomer of 90 to 30% by weight, preferably 80 to 40% by weight.
, the content of seven units derived from unsaturated dicarboxylic acid or its anhydride is 10 to 70% by weight, preferably 20 to 60% by weight, and the softening point is 60 to 200°C,
Preferably the temperature is 100 to 190°C, and the bromine number is lθ to 1
00 g/100 g, preferably 15-50 g/10
0 g, and the acid value is 100 to 500 gKOH/g, preferably 150 to 400 mgKOH/g.

In addition, from the viewpoint of raw material components, a preferable component (B) is a hydrogenated product obtained by hydrogenating a polymerization product obtained by copolymerizing cyclopentadiene and maleic anhydride.

This component (B) can be mixed with an uncured epoxy resin and the epoxy resin can be cured by setting predetermined curing conditions.

The uncured epoxy resin can be arbitrarily selected from known ones, and has at least two epoxy groups per molecule, such as brominated epoxy resin, epoxy novolak resin, bisphenol A-epichlorohydrin resin, Polyfunctional epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, etc. can be used. A typical example of these epoxy resins is a resin obtained by the reaction of bisphenol and epichlorohydrin, and is represented by the following general formula, where n is O or an integer of several tens or less. As the epoxy resin represented by the above general formula, n is 2
Or 3 or less, preferably those having an epoxy equivalent of 170 to 300. Furthermore, these epoxy resins have 3 carbon atoms.
It is also possible to add diluents such as -lO glycidyl ethers of aliphatic alcohols, such as butyl glycidyl ether, allyl glycidyl ether, and other commercially available epoxy diluents.

The epoxy diluent can be used in an amount of 20 parts by weight or less of the epoxy resin.

During curing, the blending ratio of the uncured epoxy resin and the curing agent for epoxy resin is usually 50 to 200 parts by weight, preferably 80 to 200 parts by weight, per 100 parts by weight of the epoxy resin. It is 130 parts by weight.

The curing conditions include, for example, a temperature of 100 to 200°C.
An example of this is heating for 1 to 3 hours.

Further, during curing, a curing accelerator such as tris(dimethylaminomethyl)phenol, triethylamine, diethylamine, ethanolamine, etc. may be added.

The cured epoxy resin obtained by the curing reaction has a glass transition point of 200°C or higher and has improved heat resistance. It is suitably used as a material for paints, adhesives, sealing members for various parts in electronic devices, printed wiring boards, etc.

[Effect] This invention is the first to use a hydrogenated product of a polymerization product obtained by a copolymerization reaction of a cyclopentadiene monomer and an unsaturated dicarboxylic acid or its anhydride as a curing agent for epoxy resin. It is easy to manufacture and handle, and when uncured epoxy resin is cured with this curing agent for epoxy resin, the glass transition point is 200°C.
As described above, a cured product for epoxy resin having excellent thermal shock resistance and heat resistance can be obtained. The curing agent for epoxy resins of the present invention makes it possible to provide epoxy resins suitable for electronic parts, paints, and adhesives that require heat resistance and thermal shock resistance.

[Example] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

(Examples 1 to 3) 40 g of xylene as a solvent, 100 g of cyclopentadiene, and 35 g of maleic anhydride were charged into a polymerization reaction vessel equipped with a stirrer and purged with nitrogen, and heated to 260° C. while stirring. The polymerization reaction was carried out for 3 hours.

After the reaction was completed, xylene was removed to obtain 127 g of a polymerization product resulting from a copolymerization reaction of cyclopentadiene and maleic anhydride.

The softening point of this polymerization product is 142°C, and the content of cyclopentadiene as one unit is 75% by weight.
, the bromine number is 64g/100g, and the acid number is 23
It was 3 mgKOH/g, and the Gardner hue was 18 or more.

Next, 100 g of the polymerization product and the solvent Tetra 1-19-12++188+I+R:+s Fun^, & Ja bu C- were placed in a reaction vessel equipped with a stirrer and purged with nitrogen.
cr (0.5% by weight of palladium metal supported) was charged, and hydrogen was press-injected to give a pressure of 30 kg/crn'G.
The mixture was heated to 0° C. and a hydrogenation reaction was carried out for 3.5 hours while stirring.

After the reaction was completed, the solvent, catalyst, etc. were removed to obtain 101 g of a hydrogenated product of the polymerization product.

This hydrogenated product has a softening point of 158°C, a bromine number of I B g/100 g, and an acid value of 230 mg K.
OH/g was present, and Gardner hue was 16.

This hydrogenated substance itself was used as a curing agent for epoxy resin.

Next, bisphenol type liquid epoxy resin [trade name;
1,100 parts by weight of Epicoat 828, manufactured by Shell Kagaku Co., Ltd., the hydrogen additive in the proportions shown in Table 1, and tris(dimethylaminomethyl)phenol as a curing accelerator were mixed and cured at 170°C for 2 hours. The reaction was carried out to obtain a cured epoxy resin.

For this epoxy resin cured product, JIS K6911
The bending strength and bending elastic modulus were measured according to the following, and the glass transition point was measured by dynamic viscoelasticity measurement method. In addition, this epoxy resin curing agent was placed in an oven heated to 230°C for 24W! The weight loss rate was measured after 24 hours, and the weight loss rate (weight %) was defined as heat resistance.

The results are shown in Table 1.

(Comparative Example 1.2) The same epoxy resin as used in Examples 1 to 3 and the hardening agent of the type shown in Table 1 were mixed in the proportions shown in Table 1. I did the same.

The results are shown in Table 1. Incidentally, even if the amount of curing agent added was greater than the amount shown in Table 1, no effect was obtained.

(Comparative Example 3) The same epoxy resin as used in Examples 1 to 3 and the polymerization product obtained in the above Example were mixed in the proportions shown in Table 1, but in the same manner as in the Example above. did.

The results are shown in Table 1.

As is clear from Table 1, the curing agent for epoxy resin according to the present invention provides a cured epoxy resin having a high glass transition point and improved heat resistance.

Claims (1)

[Claims] (1) A curing agent for epoxy resins, which comprises a hydrogenated product of a polymerization product obtained by a polymerization reaction of a cyclopentadiene monomer and an unsaturated dicarboxylic acid and/or its anhydride.