JPH07122054B2 - Method for producing epoxy resin adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is excellent for oil surface steel sheets by uniformly dispersing a reactive solid rubber such as a carboxyl group-containing acrylonitrile rubber in a liquid epoxy resin. The present invention relates to a method for producing an epoxy resin adhesive which is a structural adhesive having adhesive strength.

[Prior Art] Known adhesives for structural use include various adhesives such as epoxy resin-based, phenolic-based, polyurethane-based, and acrylic-based adhesives, but they can be bonded while oil is still attached to the metal surface. , For improving the so-called oil absorption performance and for obtaining high peel strength by imparting appropriate flexibility after curing, acrylonitrile-butadiene copolymer, acrylonitrile-butadiene copolymer having a carboxyl group, acrylic rubber and urethane rubber, etc. Contains the soft ingredient.

These soft ingredients are, for example, Hycar CTBN1300 ×
In the case of a liquid rubber such as 8 (trade name, manufactured by BF Goodrich), a liquid epoxy resin such as Epicoat 828
(Commercial name, manufactured by Yuka Shell Co., Ltd.) can be easily mixed to obtain a uniform composition. However, hiker 1072
In the case of a solid rubber such as (commercial name, manufactured by BF Goodrich Co., Ltd.), the compatibility with the epoxy resin is poor, and it is difficult to form a uniform composition. Therefore, various means are provided. Came.

That is, even if it is limited to the kneading method of the reactive solid rubber, for example, Hiker 1072 and the liquid epoxy resin, the Hiker 10
A method in which 72 is dissolved in an organic solvent such as methyl ethyl ketone and then mixed with a liquid epoxy resin (JP-A-51-2019).
998, 51-135936, 52-30837, 57-49646
No. 58-8773, etc.) and kneading Hiker 1072 and liquid epoxy resin while heating with a rubber roll or pressure kneader, then cooling to 30-40 ° C. and kneading a curing agent or curing aid. Method (JP-A-48-5834, JP-A-56-135579)
No. 57-70167, No. 59-78282, etc.) are known.

[Problems to be Solved by the Invention] However, in the method using a low boiling point organic solvent such as methyl ethyl ketone, if the solvent is not removed beforehand, volatilization occurs during heat curing and foaming occurs. Cannot be used. Moreover, even though it is an organic solvent having a low boiling point, it is very difficult to completely remove the solvent because the mixture of the rubber and the epoxy resin has a high viscosity. Method is used. However, in such a case, since the rubber reacts and the viscosity increases, it is necessary to adjust the viscosity, and it is necessary to take measures to prevent environmental pollution due to volatilization of the solvent, and the manufacturing facility becomes complicated, The expense for that will also increase.

On the other hand, even in the method of kneading with a rubber roll or a pressure kneader, it is not possible to uniformly disperse the liquid epoxy resin while adding the epoxy resin little by little while masticating the rubber. 107
When 2 is softened and kneaded, there is a drawback in that gelation proceeds unless the temperature is lowered to around room temperature when kneading a curing agent or a curing aid thereafter, and the intended adhesive cannot be obtained. Also, in actual production, raising and lowering the temperature with one roll (or kneader) is extremely disadvantageous in terms of heat management, so prepare two heating rolls (or kneaders) and cooling rolls (or kneaders). However, the equipment cost and the operating cost for that are increased.
Further, when the rubber and the epoxy resin are kneaded by heating at about 100 ° C., the rubber reacts and the viscosity increases, so that the viscosity must be adjusted and strict process control is required.

[Means for Solving Problems] The present invention is an improvement over these conventional drawbacks. According to the present invention, a reactive solid rubber is uniformly dispersed in a liquid reactive diluent at room temperature. Then, when producing an epoxy resin adhesive by mixing with an epoxy resin, with respect to 100 parts by weight of the reactive solid rubber, the reactive diluent is used in an amount of 10 parts by weight or more and less than 1000 parts by weight, and A mixture of the reactive solid rubber and the reactive diluent is mixed with an epoxy resin.
Provided is a method for producing an epoxy resin-based adhesive, which is used in the range of 5 to 200 parts by weight with respect to 100 parts by weight.

That is, for example, a reactive solid rubber such as Hiker 1072, which is an acrylonitrile-based rubber having a carboxyl group, and a reactive diluent that is compatible at both room temperature with a liquid epoxy resin and is reactive at room temperature. The solid rubber and the diluent are first kneaded by a kneader to be uniformly dispersed, and then a liquid epoxy resin is added and kneaded to obtain a uniform composition.

If the production method of the present invention is used, it is not necessary to remove the solvent after kneading, and it is not necessary to adjust the temperature of the roll or the kneader variously, the operation is extremely simple, and other kneading methods according to conventional techniques have a problem. This is a very simple and effective kneading method that eliminates all the above drawbacks.

The epoxy resin used in the present invention is a prepolymer having two or more highly reactive epoxy groups in the molecule, that is, bisphenol A type, bisphenol F type, novolac type, cycloaliphatic type, polyfunctional phenol type, Among the polyfunctional glycidyl amine type epoxy compounds, those that are liquid at room temperature. As a specific example, Epicoat
828 is mentioned.

As the reactive solid rubber, an acrylonitrile rubber containing a carboxyl group, for example, an acrylonitrile-butadiene copolymer is preferably used. It is used for the purpose of improving the adhesive strength by imparting flexibility and flexibility to the adhesive, as well as improving the so-called oil absorption performance in which oil can be adhered to the adherend surface while adhering.
Specific examples include Hiker 1072 and Hiker 1472 (manufactured by BF Goodrich).

The reactive diluent is a compound that is liquid at room temperature, such as glycidyl ether type, glycidyl ester type or glycidyl amine type, and has one or more glycidyl groups and / or ester groups, ether groups or amino groups in the molecule. It is a general term for compounds having groups and the like, and specific examples thereof include phenyl glycidyl ether and glycidyl methacrylate.

In the present invention, it is preferable to use the reactive diluent in an amount of 10 parts by weight or more and less than 1000 parts by weight, particularly 20 parts by weight or more and 500 parts by weight or less, based on 100 parts by weight of the reactive solid rubber. These reactive diluents not only have compatibility with both the reactive solid rubber and the liquid epoxy resin, but also increase the affinity for the oil surface and impart flexibility after curing,
It has the effect of giving high peel strength. However, when the amount of the reactive diluent used is less than 10 parts by weight, the compatibility with the liquid epoxy resin becomes insufficient and it is difficult to obtain a uniform composition, while when it exceeds 1000 parts by weight, the degree of curing decreases, In either case, it becomes difficult to obtain high adhesive strength.

Further, the mixture of the reactive solid rubber and the reactive diluent is 5 to 200 parts by weight, especially 10 to 15 parts by weight with respect to 100 parts by weight of the epoxy resin.
It is preferably used in the range of 0 parts by weight. In the range of 10 to 50 parts by weight, a paste-like adhesive composition is obtained,
In the case of the range of 150 parts by weight, the adhesive shape of the obtained adhesive composition maintains a sheet-like viscosity, and after being formed into a sheet, the adhesive workability is improved and the oil absorption on the oil surface is improved. It exhibits excellent adhesive strength not only at high temperatures but also at low temperatures.

In the present invention, when a mixture obtained from a reactive solid rubber and a reactive diluent is kneaded with a liquid epoxy resin, or after kneading, a curing agent or a curing aid, and optionally aluminum, silicon dioxide, Fine powder of an inorganic substance such as carbon black and / or an organic substance can be appropriately kneaded.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.
It will be clear that the invention is not limited to these examples.

Example 1 To 50 g of a carboxyl group-containing acrylonitrile-butadiene copolymer (Hiker 1072) as a reactive solid rubber, 150 g of alkylphenol monoglycidyl ether was added and kneaded at room temperature for 2 hours to obtain a uniform mixture. 40g of this mixture and 160g of liquid epoxy resin (Epicoat 828)
Was kneaded at room temperature for 2 hours, then 4 g of dicyandiamide and 6 g of amorphous silica were added and kneaded for 1 hour to obtain an adhesive composition. Next, the adhesive strength of the obtained adhesive composition was measured.

First, the tensile shear strength was measured according to JIS K6850. That is, the test piece for measuring the tensile shear strength is a 25 mm x 200 mm x 1.6 mm mild steel plate (SPCC-SD) that has been degreased with trichlene in advance and then thinly coated with rust preventive oil [Metal Guard # 831 (manufactured by Mobil Oil Co., Ltd.)]. To one of the two, attach a rectangular Teflon spacer with a thickness of 0.15mm so as to have an area of 12.5mm x 25mm, apply an adhesive to the surface, and overlay the other one to prevent misalignment. After clip-fastening 2 places,
It was heat-cured in a gear oven at 0 ° C for 20 minutes. The test piece thus obtained was pulled at 5 mm / min using a Tensilon tensile tester manufactured by Toyo Baldwin Co., Ltd., and the tensile shear strength was measured. The results obtained are shown in Table 1.

On the other hand, the T-type peel strength was measured according to JIS K6854. For the T-type peel strength measurement test piece, one of two 25 mm × 200 mm × 0.8 mm mild steel plates that had been surface-treated in the same manner as described above was coated with an adhesive to have an area of 100 mm × 25 mm. Then, several glass beads having a diameter of 0.15 mm were sprinkled thereon, and then another glass sheet was superposed on the glass beads, and several portions were clipped so as not to be displaced, and then heat-cured under the same conditions as above. The test piece prepared in this manner was measured at 200 mm / min using a Tensilon tensile tester manufactured by Toyo Baldwin.
And the T-type peel strength was measured. The results obtained are shown in Table 1.

Example 2 41 g of Hiker 1072 and 20 g of a reactive diluent (glycidyl methacrylate) were kneaded for 2 hours at room temperature with a kneader to obtain a uniform mixture. Next, 100 g of a mixture obtained by mixing Epicoat 828 and Epicoat 604 in a ratio of 6 to 4 in advance, 72 g of aluminum, 4.5 g of amorphous silica, and 3 g of KBM-403 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent are added for 2 hours. Kneaded After that, 7.5 g of dioltotolyl guanidine, 4.5 g of dicyandiamide and 3 g of dimethylbenzylamine were added as a curing agent component and kneaded for 1 hour to obtain an adhesive composition, which was sandwiched between two release papers and 100 kg /
A sheet having a thickness of 0.25 mm was prepared under a pressure of cm ² .

The adhesive strength of the adhesive thus obtained was measured by the same method as in Example 1, and the results are shown in Table 1.

(Comparative Example 1) 1 g of Hiker 1072 was dissolved in 10 ml of acetone in a mortar, and 9 g of epoxy resin [EP-4000 (trade name, manufactured by Asahi Denka Co., Ltd.)] and 10 g of Epicoat 828 were added and mixed well to obtain a uniform mixture. A mixture was obtained. Next, acetone was completely volatilized while kneading on a hot plate at 100 ° C., and after returning to room temperature, 1.6 g of dicyandiamide and 0.4 g of dimethylbenzylamine were added and mixed well to obtain an adhesive composition. The adhesive strength of this product was measured by the same method as in Example 1, and the results are shown in Table 1.
Shown in.

(Comparative Example 2) Epicoat 604 while masticating 50g of hiker 1072 at room temperature
100 g was added little by little and kneaded for 2 hours. After kneading, small granules still existed and it was not a uniform mixture, but while mixing 30g of the mixture, Epicoat 828 170g
Add little by little and knead for 2 hours, then aluminum 96
g, amorphous silica 6 g, dicyandiamide 16 g, and dimethylbenzylamine 4 g were added and kneaded for 1 hour to obtain an adhesive composition. A small amount of small particles were also present in this adhesive composition, and the composition was not uniform. The adhesive strength of this product is shown in Table 1.

(Comparative Example 3) Hiker 1072 10 g, alkylphenol monoglycidyl ether 30 g, Epicoat 828 160 g and amorphous silica 6 g were kneaded at room temperature with a kneader, but many particles were present even after 2 hours. To this was added 16 g of dicyandiamide, 4 g of dimethylbenzylamine and 6 g of amorphous silica, and the mixture was kneaded for 1 hour to obtain an adhesive composition. The adhesive strength of this product is shown in Table 1.

(Comparative Example 4) 50 g of Hiker 1072 and 3 g of alkylphenol monoglycidyl ether were kneaded with a kneader for 2 hours at room temperature. When 10.6 g of this mixture was kneaded with 189.4 g of Epikote 828 for 2 hours with a kneader, a large number of particles were present and a uniform composition could not be obtained. 16 g of dicyandiamide, 4 g of dimethylbenzylamine and 6 g of amorphous silica were added to this mixture and kneaded for 1 hour to obtain an adhesive composition. The adhesive strength of this product is shown in Table 1.

(Comparative Example 5) Hiker 1072 40 g and alkylphenol monoglycidyl ether 160 g were added and kneaded at room temperature with a kneader for 2 hours, then 100 g of this mixture was further added with alkylphenol monoglycidyl ether 120 g and kneaded for 2 hours to obtain a uniform mixture. Got Epicoat on 110 g of the resulting mixture
Add 828 90g and knead for 2 hours, then dicyandiamide
16 g, dimethylbenzylamine 4 g and amorphous silica 6 g were added and kneaded for 1 hour to obtain an adhesive composition. The adhesive strength of this product was measured by the same method as in Example 1, and the results are shown in Table 1.

(Comparative Example 6) Hiker 1072 (100 g) and alkylphenol monoglycidyl ether (100 g) were kneaded with a kneader for 2 hours at room temperature.
8g of this mixture and 192g of Epikote 828 are kneaded in 2
After kneading for a long time, many particles were present and a uniform composition could not be obtained. To this mixture, 16 g of dicyandiamide, 4 g of dimethylbenzylamine and 6 g of amorphous silica were added and kneaded for 1 hour to obtain an adhesive composition. The adhesive strength of this product is shown in Table 1.

(Comparative Example 7) Hiker 1072 (40 g) and alkylphenol monoglycidyl ether (100 g) were kneaded at room temperature in a kneader for 2 hours, and 140 g of this mixture and Epicoat 828 (60 g) were further kneaded for 2 hours to obtain a uniform composition. Hereinafter, an adhesive composition was prepared in exactly the same manner as Comparative Example 6, and the adhesive strength of this is shown in Table 1.

(Comparative Example 8) 50 g of natural rubber RSS1 (International Rubber International Product Specification) and 150 g of alkylphenol monoglycidyl ether were kneaded for 2 hours at room temperature with a kneader, and 40 g of this mixture and Epicoat 8
28 160 g was added and kneaded with a kneader for 2 hours to obtain a uniform composition. Hereinafter, an adhesive composition was prepared in exactly the same manner as Comparative Example 6, and the adhesive strength of this is shown in Table 1.

[Effects of the Invention] As described above, the production method according to the present invention is simpler in operation than the conventional production method, and the adhesive composition obtained has high adhesive strength and excellent performance. This is a very effective method that can produce an excellent structural adhesive particularly for oil-faced steel sheets.

Front page continuation (72) Kenji Kawanishi 3-10 Nakamiyakitamachi, Hirakata-shi, Osaka Ube Industries, Ltd. Hirakata Laboratory (56) References JP-A-54-159450 (JP, A) JP-A-59-221372 (JP, A) JP-A-61-271363 (JP, A)

Claims (3)

[Claims] 1. A reactive solid rubber is uniformly dispersed in a liquid reactive diluent at room temperature, and then mixed with an epoxy resin to produce an epoxy resin adhesive. 10 parts by weight or more and less than 1000 parts by weight of the reactive diluent and 5 to 200 parts by weight of the mixture of the reactive solid rubber and the reactive diluent with respect to 100 parts by weight of the epoxy resin. A method for producing an epoxy resin-based adhesive, which is used within the range of parts. 2. The method according to claim 1, wherein the reactive solid rubber is a carboxyl group-containing acrylonitrile rubber. 3. The method according to claim 1, wherein the reactive diluent is a glycidyl ether type compound, a glycidyl ester type compound or a glycidyl amine type compound.