JPH075706B2 - Solid epoxy resin, method for producing the same, and composition thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing a solid epoxy resin, a solid epoxy resin having novel physical properties and a composition thereof, and more specifically, to an epoxy equivalent of the solid epoxy resin ( EEW)
And a method for producing a solid epoxy resin capable of arbitrarily controlling the softening point (X) within a specific range, having unique physical properties in the relationship between the epoxy equivalent (EEW) and the softening point (X), and having a number average molecular weight (Mn) The present invention relates to a solid epoxy resin having a novel range in terms of the component ratio (Y) having a molecular weight of 5000 or more, and a curable composition obtained by blending the solid epoxy resin and a curing agent.

[Prior Art] Epoxy resin has excellent properties such as electric insulation, heat resistance, corrosion resistance, and adhesion, has a large degree of freedom in compounding, and can change the characteristics of a cured product depending on the purpose of use. Further, since it is used in various forms such as powder, paste and liquid, it is widely used in various fields. However, in the case of producing a solid epoxy resin, according to the conventional method of charging raw materials before the start of the reaction, the softening point (X) and the number average molecular weight (Mn) have a certain correlation (H. Lee: Handbook of Epoxy Resing,
1967). For example, a bifunctional epoxy resin generally has two epoxy groups at the ends of its molecule, and therefore the value obtained by doubling EEW is the number average molecular weight (Mn). Therefore, a resin with a high EEW, that is, a high Mn, has a high softening point (X),
The resin having a low Mn, that is, a low Mn has a low softening point (X).

However, there are applications where low EEW and high softening point (X) are required at the same time, including coating applications, and epoxy resins and curable compositions containing such epoxy resins have been required for many years.

[Problems to be Solved by the Invention] As a measure against this, by copolymerizing an epoxy resin or phenol having a functionality of more than 2, a resin having a high softening point and a low EEW as compared with a conventional resin is produced. Has been tried.

However, in this reaction as well, the polymerization monomer is charged before the start of the reaction in the same manner as in the conventional method, and therefore there is a limit to the amount of the epoxy resin or phenols having a functionality of more than 2 to prevent gelation of the resin. The resin that has achieved the task sufficiently has not been obtained yet.

[Means and Actions for Solving the Problems] The inventors of the present invention have conducted intensive studies on a method of producing a resin having a high softening point and a low EEW after solving the danger of gelation. Reached

The present invention provides a solid epoxy resin having a low EEW and a high softening point, which cannot be achieved by conventional manufacturing methods, and a method for manufacturing the same, and a cured product composition containing the obtained solid epoxy resin. It is to provide things.

That is, the present invention has a reaction rate of a phenolic hydroxyl group of 50 in the polymerization of an epoxy resin and a phenol in which the molar ratio of the epoxy group and the phenolic hydroxyl group in the raw material is 0.4 to 0.99 (phenolic hydroxyl group / epoxy group). %, The polymerization system should be added by adding the epoxy resin and phenol, and adding the polymerization system so that the molar ratio of epoxy group and phenolic hydroxyl group is 0.0368-0.6 (phenolic hydroxyl group / epoxy group). The method for producing a solid epoxy resin characterized in that the relationship between the epoxy equivalent (EEW) and the softening point (X) is 300 ≦ EEW ≦ 1500, 1 / 20EEW + 45 ≦ X ≦ 140, and the molecular weight in GPC measurement is 5000 or more. A solid epoxy resin composed of an epoxy resin and a phenol, in which the relationship between the component ratio (Y) and the number average molecular weight (Mn) is 600 ≦ Mn ≦ 3000 1 / 48Mn-12.5 ≦ Y ≦ 90, and at least A curable composition containing the solid epoxy resin and a cured product.

The present invention will be described in detail below.

The method for producing a solid epoxy resin in the present invention can be roughly divided into two steps. The first step is a step of polymerizing epoxy resins and phenols. Here, the polymerization is a polyaddition reaction between an epoxy group of an epoxy resin and a phenolic hydroxyl group of a phenol. Since the first step is a step of producing a high molecular component by polymerization, the molar ratio of the epoxy group and the phenolic hydroxyl group in the raw material charged is 0.
4 to 0.99 (phenolic hydroxyl group / epoxy group). Furthermore, the reaction rate of phenolic hydroxyl groups is 50% or more, and it is desirable that the reaction rate is as high as possible. The reaction in the first step is 120
It is carried out at a temperature of from ℃ to 240 ℃, preferably from 150 ℃ to 190 ℃. The reaction time is usually in the range of 30 minutes to 9 hours, but what is important here is to employ the time necessary and sufficient for producing the polymer component to secure the softening point. The first step is a step of producing a polymer component to secure the softening point, but in the first step alone, the relationship between the EEW of the solid epoxy resin and the softening point (X) can be arbitrarily controlled within a specific range. is not.

Therefore, the second step is required. EE of resin in the second step
To reduce W, epoxy resins and a small amount of phenols are added to the reaction system of the first step and the polymerization is continued. Second
The molar ratio of the epoxy group and the phenolic hydroxyl group in the raw material charged in the step is 0.0368 to 0.6 (phenolic hydroxyl group / epoxy group) or less, and it is desirable to be as low as possible.

The reaction in the second step is 120 ° C to 240 ° C, preferably 150 ° C
To a temperature of 190 ° C. The reaction time is 10 minutes to 12 hours, preferably 30 minutes to 9 hours.

The ratio of the raw materials used in the first step and the second step, that is, the ratio of the weight sum of the epoxy resins used in the first step and the phenols and the weight sum of the epoxy compounds used in the second step and the phenols is , It depends on the concentration of epoxy groups and phenolic hydroxyl groups of the epoxy resins and phenols used, and it should be changed depending on the physical properties of the solid epoxy resin at the end of the reaction in the second step. A range of about 30 is preferable.

The epoxy resins and phenols used in the first step and the epoxy resins and phenols used in the second step may be the same or different. Further, in the first step or the second step, it is also possible to mix and use two or more kinds of different epoxy resins and phenols.

Epoxy resins are epoxy resins and alicyclic epoxy resins obtained from monohydric or polyhydric phenols and epihalohydrin, and are represented by general formula (1), general formula (2) or general formula (3). It is a resin or an alicyclic epoxy resin.

General formula (1) In the formula, n is an integer of 0 to 5. R is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an allyl group, a hydroxyl group and a halogen atom.

General formula (2) In the formula, n is an integer of 0 to 4. R ₁ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an allyl group and a halogen atom. R ₂ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, and an allyl group.

General formula (3) In the formula, the range of l is 2 <l ≦ 50. n is an integer from 0 to 4. m is an integer from 0 to 3. R ₁ is a hydrogen atom,
It is the same or different group selected from an alkyl group having 1 to 8 carbon atoms, an allyl group and a halogen atom. R ₂ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms and an allyl group.

To be specific, glycidyl ethers of monophenols such as phenol, cresol, and butylphenol, or diglycidyl ethers of bisphenols such as bisphenol-A, bisphenol-F, bisphenol-AD, hydroquinone, and catechol, or glycidyl ethers of novolac-type phenolic resins Typical examples thereof include polyfunctional epoxy resins and alicyclic epoxy resins, but the invention is not limited thereto.

Phenols are monohydric or polyhydric phenols, and are phenols represented by the general formula (4), the general formula (5) or the general formula (6).

General formula (4) In the formula, n is an integer of 0 to 5. R is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an allyl group, a hydroxyl group and a halogen atom.

General formula (5) In the formula, n is an integer of 0 to 4. R ₁ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an allyl group and a halogen atom. R ₂ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms and an allyl group.

General formula (6) In the formula, the range of l is 2 <l ≦ 50. n is an integer of 0-4. m is an integer of 0-3. R ₁ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an allyl group and a halogen atom. R ₂ is the same or different group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms and an allyl group.

Specifically, monophenols such as phenol, cresol and butylphenol, or bisphenol-A,
Examples thereof include bisphenols such as bisphenol-F, bisphenol-AD, hydroquinone, and catechol, and polyphenol resins typified by novolac-type phenol resins, but are not limited thereto.

A catalyst can be used as necessary in the above-mentioned invention. The catalyst to be used is a hydroxide of an alkali metal, a hydroxylated compound of an alkaline earth metal and a ring-opening of an epoxy group with a hydroxyl group such as an organic acid salt or an imidazole, an amine, a quaternary ammonium salt or a quaternary phosphonium salt thereof. Known catalysts that catalyze the reaction can be used.

Addition of an inert solvent such as toluene or xylene methyl isobutyl ketone in the production process of the present invention at the beginning, the middle or after the reaction lowers the viscosity of the reaction product and improves the handling quality. In a sense
This is one of the effective means.

The solid epoxy resin of the present invention has a great difference from the conventional epoxy resin in the relationship between EEW and the softening point (X).
That is, when the EEW of the conventional epoxy resin is, for example, 300, the softening point (X) is around 58 ° C.
Of 1,500, the softening point (X) was around 118 ° C. However, the solid epoxy resin of the present invention is not such that the relationship between the EEW and the softening point (X) is fixed in this way,
It is characterized by showing physical properties within a range surrounded by points A, B, C and D in FIG. For example, when the EEW is 300, the softening point (X) has an arbitrary softening point in a wide range of 60 to 140 ° C. Similarly, when the EEW is 1500, the softening point (X) can be any softening point (X) within a wide range of 120 to 140 ° C.
Have. This is a great feature that conventional epoxy resins cannot have. This feature is due to the fact that the component ratio (Y) of Mn to a molecular weight of 5000 or more is unique compared to conventional epoxy resins. That is, when Mn of the conventional epoxy resin is about 600, the component ratio (Y) of molecular weight 5000 or more
Is 0 (wt%), and when Mn is about 3000, the molecular weight is 5000
The above component ratio (Y) is about 50%. However, the solid epoxy resin of the present invention exhibits physical properties within the range surrounded by points E, F, G and H in FIG. For example, when Mn is about 600, the component ratio (Y) with a molecular weight of 5000 or more is 0 to 90 (wt
%) In a wide range. Also, Mn is 30
When it is around 00, the component ratio (Y) with a molecular weight of 5000 or more is 50 to 90.
(Wt%) It has an arbitrary component ratio in a wide range.

That is, the epoxy resin of the present invention has a peculiar limited range in the relationship between EEW and the softening point (X), and at the same time, a peculiar limited range in the relationship between Mn and the component ratio (Y) having a molecular weight of 5000 or more. It has a high softening point (X) and a low EEW as compared with the conventional epoxy resin.

The curable composition of the present invention contains at least the solid epoxy resin and a curing agent.

Epoxy resin has a heat resistance in a composition with a curing agent,
It has excellent hardness, elastic modulus and chemical resistance, and is widely used in civil engineering and construction materials, paints, lining materials, electrical equipment molding materials, machine parts, electronic parts, matrix resins for fiber reinforced composite materials, etc. There is. The curable composition of the present invention is suitable for any of these conventional uses.

As the curing agent, any one or a plurality of commercially available curing agents may be selected and used. Examples of such a curing agent include aliphatic primary amines, aromatic primary amines, secondary and tertiary amines, amines such as polyamide resin, aromatic acid anhydrides, cyclic fatty acid anhydrides, and aliphatic acids. Acid anhydrides such as anhydrides, polycarboxylic acid anhydrides, halogenated anhydrides, chloresic acid anhydrides, imidazoles,
Quaternary salts, boron trifluoride-amine complex, dicyandiamide and its derivatives, organic acid hydrazides, diaminomaleonitrile and its derivatives, melamine and its derivatives, amine imides, polyamine salts, novolac phenol resins, mevolac cresol resins, etc. Examples thereof include oligomers, isocyanates and blocks thereof.

Such a curing agent is added to the solid epoxy resin of the present invention in an amount of 1 to 50 wt.
% Is added. The amount to be added should be determined according to the application required physical properties of the curable composition.

Further, one or a plurality of ordinary epoxy resins can be selected and added to the present curable composition, if necessary. Usually as an epoxy resin, for example, bisphenol
A, bisphenol F, bisphenol S, novolac type epoxy resin, brominated bisphenol type epoxy resin, glycidyl ether epoxy resin, cycloaliphatic epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, heterocyclic epoxy Resin can be mentioned.

A filler, a diluent, and a curing accelerator can be added to the curable composition, if necessary.

The curable composition of the present invention is suitable for coatings such as powder coatings and baking coatings, medium to high temperature curing adhesives, sealing and impregnation of electric and electronic parts, casting agents and the like.

[Example] A more specific description will be given below with reference to an example.

The method of analyzing the resins obtained in the examples will be described below.

(1) The softening point (X) was measured by JIS standard analysis method K2207. As the apparatus, a ring-and-ball type automatic softening point tester model ASP-M4P manufactured by Meihosha Co., Ltd. was used.

(2) EEW was measured by JIS standard analysis method K7236.

(3) The GPC measurement was carried out by equipping a Toyo Soda Co., Ltd. 802 type GPC device with a Toyo Soda Co., Ltd. RI-8 type detector. Tetrahydrofuran is used as the mobile phase and the flow rate is 1.5 ml / min.
Was measured at. As the GPC column, one Showdex A804 manufactured by Showa Denko KK, one A803, and two A-802 were used. For the measurement of the molecular weight, a calibration curve (shown in FIG. 4) was prepared using the elution time and molecular weight of the GPC chromatogram, and calculation was performed using a Waters Model 730 data module. The component ratio (Y) having a molecular weight of 5000 or more was determined by cutting out the GPC chromatogram and measuring the weight.

(4) Flowability was measured by using a 13 mmφ mold and
Compress it at 0kg / cm ² to get a tablet.
In an electric heating furnace at ℃, it was placed on an iron plate with a smooth surface and inclined by 10 degrees and melted, and the flow length after 30 minutes was measured.

(5) Adhesion is measured according to JIS K6850 “Tensile-shear adhesive strength test method” by sandwiching 0.3 g of the composition on the iron-iron bonded part and firing at 200 ° C. for 30 minutes in an electric heating furnace. The test pieces were then tested for tensile shear bond strength within 120 ° C. heat.

(6) Regarding blocking resistance, the presence or absence of blocking was confirmed by storing the ground composition in an electric heating furnace at 35 ° C. for 24 hours.

(7) The bendability was evaluated according to JIS5400-6-16, which is the number of coated plates corresponding to the gap between the bends.

Example 1 350 parts by weight of bisphenol A type liquid epoxy resin AER-331 (Asahi Kasei Corporation) (hereinafter abbreviated as DGEBA) having EEW = 190 in a separable flask equipped with a thermometer, a stirrer, and a mantle heater, bisphenol A (Hereinafter abbreviated as BPA)
160 parts by weight and 0.01 part by weight of 2-phenylimidazole (hereinafter abbreviated as 2PZ) as a polymerization catalyst were charged, and the temperature was raised from room temperature to 180 ° C with stirring. After that, at 180 ℃ for 4 hours,
Kept warm. The EEW of the polymer was 1,100. 650 parts by weight of DGEBA and 120 parts by weight of BPA were added to the polymer kept at 180 ° C., and polymerization was carried out at 180 ° C. for another 5 hours while keeping the temperature unchanged. The produced resin had an EEW of 470 and a softening point (X) of 80 ° C. Moreover, the result of having measured the molecular weight distribution of this resin by GPC is shown in FIG. Number average molecular weight calculated from GPC (M
n) was 900, and the component ratio (Y) having a molecular weight of 5000 or more was 12%.

Comparative Example 1 A separable flask equipped with a thermometer, a stirrer, and a mantle heater was charged with 1000 parts by weight of DGEBA, 320 parts by weight of BPA, and 0.01 parts by weight of 2PZ as a polymerization catalyst, and stirred from room temperature. The temperature was raised to 180 ° C. Then, the temperature was kept at 180 ° C. for 5 hours. The softening point (X) of the polymer was 77 ° C. and the epoxy equivalent was 550. In addition, the molecular weight distribution of this resin
The result of measurement in Table 3 is shown in FIG. The number average molecular weight (Mn) calculated from GPC was 1050, and the component ratio (Y) having a molecular weight of 5000 or more was 6%.

Examples 2 to 4 Solid epoxy resins were obtained by the same method as in Example 1 except that the amounts of the epoxy resins and phenols in the first step and the second step as shown in Table 1 were used. Table 1 shows the softening point (X) of the obtained solid epoxy resin, the EEW, the number average molecular weight (Mn) obtained from GPC measurement, and the component ratio (Y) of the molecular weight of 5000 or more.

Example 5 A separable flask equipped with a thermometer, a stirrer, and a mantle heater was charged with 500 parts by weight of DGEBA, 250 parts by weight of BPA, and 0.01 parts by weight of 2PZ as a polymerization catalyst, and the temperature was raised from room temperature to 180 ° C. with stirring. Warmed. Then, the temperature was kept at 180 ° C. for 4 hours. The EEW of the polymer was 2,100. 500 parts by weight of cresol novolac type epoxy resin AER-ECN273 (hereinafter abbreviated as ECN) having EEW = 210 to the polymer kept at 180 ° C.,
10 parts by weight of BPA was added and polymerization was carried out at 180 ° C. for 5 hours while keeping the temperature. The produced resin had an EEW of 410 and a softening point (X) of 115 ° C.

Comparative Examples 2 to 3 Solid epoxy resins were obtained in the same manner as in Comparative Example 1 except that the amounts of epoxy resins and phenols shown in Table 1 were used. Softening point (X), EE of the obtained solid epoxy resin
Table 1 shows the average molecular weight (Mn) and the like obtained from W and GPC measurements.

Comparative Example 4 In a separable flask equipped with a thermometer, a stirrer, and a mantle heater, 500 parts by weight of DGEBA and 500 parts by weight of ECN,
250 parts by weight of BPA and 0.01 parts by weight of 2PZ as a polymerization catalyst were charged, and the temperature was raised from room temperature to 180 ° C. with stirring. Then, when the polymerization was carried out while keeping the temperature at 180 ° C., the resin gelled.

Comparative Example 5 1000 parts by weight of DGEBA having an EEW of 190 was added to a separable flask equipped with a thermometer, a stirrer, and a mantle heater, and BPA.
280 parts by weight, 0.01 parts by weight of 2PZ as a polymerization catalyst,
The temperature was raised from room temperature to 180 ° C with stirring. Then 180 ° C
It was kept warm for 9 hours. The EEW of the polymer is 500 and the softening point (X) is
It was 68 ° C. Further, the number average molecular weight (Mn) calculated from GPC of this resin was 940, and the component ratio (Y) having a molecular weight of 5000 or more was 4%.

Example 6 Table 2 shows the results of evaluation of the curable composition of the present invention.
The composition was obtained by melting and kneading the epoxy resin, the curing agent and the filler obtained in Example 1 and then cooling and crushing the resulting curable composition to obtain flowability, adhesion, blocking resistance and bending property. Was measured.

Comparative Example 6 The composition of the comparative example is AER661R (EEW =
460, softening point 67 ° C., n = 910) except that the same compounding, kneading, and pulverization as in Example 7 was performed.

Example 7 100 parts of a solid epoxy resin having an EEW of 550, a softening point (X) of 90 ° C., an Mn of 1100 and a component ratio (Y) of 5,000 or more in molecular weight of 35%, and Hitanol 401 (manufactured by Hitachi Chemical: Resol type phenol resin, solid content concentration 50%) 50 parts, toluene 10
0 parts, 100 parts of n-butanol and 100 parts of methyl isobutyl keto were blended, applied on a TFS plate, and baked at 200 ° C. for 6 minutes. A transparent, hard coating film was obtained.

[Effects of the Invention] When the production method of the present invention is used, the EEW of a solid epoxy resin is
The softening point (X) can be arbitrarily controlled within a specific range. Further, the solid epoxy resin of the present invention is characterized in that it has a high softening point (X) and a low EEW as compared with conventional epoxy resins. Further, the curable composition of the present invention is suitable for various paints, sealing agents, impregnating agents, and casting agents.

[Brief description of drawings]

1 and 2 are graphs showing the relationship between the softening point (X) and EEW of the solid epoxy resin of the present invention, the relationship between the number average molecular weight (Mn) and the component ratio (Y) of 5,000 or more, respectively. FIG. 3 is a graph showing the molecular weight distribution of the solid epoxy resin of the example measured by GPC, and FIG. 4 is a calibration curve in GPC measurement.

Continuation of front page (56) Reference JP-A-63-48324 (JP, A) JP-A-63-48323 (JP, A) JP-A-59-96178 (JP, A) JP-A-58-19322 (JP , A) Japanese Patent Laid-Open No. 50-156600 (JP, A) Special Table 62-502621 (JP, A)

Claims (3)

[Claims] 1. A reaction rate of a phenolic hydroxyl group is 50% in the polymerization of an epoxy resin and a phenol in which a molar ratio of an epoxy group and a phenolic hydroxyl group in a raw material is 0.4 to 0.99 (phenolic hydroxyl group / epoxy group). At the above stage, the epoxy resin and the phenol are added to the polymerization system so that the molar ratio of the epoxy group and the phenolic hydroxyl group is 0.0368 to 0.6 (phenolic hydroxyl group / epoxy group), and the polymerization is continued. A method for producing a characteristic solid epoxy resin. 2. The relationship between the epoxy equivalent (EEW) and the softening point (X) is 300 ≦ EEW ≦ 1500, 1 / 20EEW + 45 ≦ X ≦ 140, and the component ratio (Y) is 5,000 or more in GPC measurement. A solid epoxy resin composed of an epoxy resin and a phenol having a relationship with the number average molecular weight (Mn) of 600≤Mn≤3000 1 / 48Mn-12.5≤Y≤90. 3. A curable composition containing at least the solid epoxy resin according to claim 2 and a curing agent.