JP5457658B2 - Main agent-primer type thermosetting epoxy resin and curing method thereof - Google Patents

Description

  The present invention relates to a thermosetting epoxy resin, and more particularly to a main agent-primer type thermosetting epoxy resin and a curing method thereof.

  In order to cure an epoxy resin with a thiol curing agent, a curing temperature of 150 ° C. or higher is usually required. However, it is not preferable to expose the substrate to a high temperature such as 150 ° C. or higher for curing. When an amine curing accelerator is used, the epoxy resin can be cured at a low temperature. However, there is a problem that the pot life is shortened as the curing temperature is lowered. For example, when a cyclic amine curing accelerator is added to a mixture of an epoxy resin and a thiol compound, a curing reaction occurs instantaneously.

  As a method for improving the pot life, there is a method in which an epoxy resin and a curing agent are divided into a two-component type. However, this two-component type epoxy resin has a drawback that the physical properties of the cured product are easily affected by the variation in the mixing ratio of the solutions, that is, it is difficult to manage for stable performance. There was a drawback that a hardened portion was likely to occur.

As another method for improving the pot life, there is a method of forming a one-component type containing a latent curing accelerator that functions as an accelerator that is insoluble in an epoxy resin at room temperature and solubilized by heating. (Patent Document 1). However, this one-pack type epoxy resin has drawbacks such as that a sufficient pot life cannot always be obtained, that the curing rate at low temperature is not always sufficient, and that a special latent curing accelerator is required. It was.
JP-A-6-211969

  An object of the present invention is to provide an epoxy resin which can be cured at a low temperature and can be cured for a short time, has an improved pot life, and provides a stable physical property of a cured product.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have made the epoxy resin and the curing agent into one component (main agent composition) and the curing accelerator as a treatment agent (primer composition). In addition, the pot life of the epoxy resin itself is improved, low-temperature curing and short-time curing are possible, and since it is not necessary to mix two liquids, the present inventors have found that the physical properties of the cured product can be stabilized.

  The present invention includes (A) a primer composition containing one or more curing accelerating compounds selected from amine compounds and imidazole compounds, (B) (1) an epoxy resin having two or more epoxy groups in the molecule, and (2) A main agent-primer-type thermosetting epoxy resin comprising a polythiol compound having two or more thiol groups in the molecule or a main agent composition containing an acid anhydride.

  In the present invention, a primer composition containing one or more curing accelerating compounds selected from (A) an amine compound and an imidazole compound is applied to a substrate to obtain a primer coating layer, and (B) (1 After applying a main agent composition containing an epoxy resin having two or more epoxy groups in the molecule and (2) a polythiol compound or acid anhydride having two or more thiol groups in the molecule to obtain a main agent coating layer, This is a curing method for a main agent-primer type thermosetting epoxy resin, which includes heat curing both coating layers.

  In the present invention, (A) a primer composition containing one or more curing accelerating compounds selected from an amine compound and an imidazole compound is applied to a substrate to obtain a primer coating layer, and (B) (1) an epoxy group in the molecule (2) A main agent composition containing a polythiol compound or acid anhydride having two or more thiol groups in the molecule is applied to another substrate to obtain a main agent coating layer, and then both coatings This is a curing method for a main agent-primer type thermosetting epoxy resin, which includes curing a layer by thermocompression bonding.

  According to the present invention, it is possible to provide an epoxy resin which can be cured at a low temperature and can be cured for a short time, has an improved pot life, and provides a stable physical property of a cured product.

  Since the present invention cures quickly at low temperatures, it is suitable for applications such as adhesives and paints, and is suitable for mass production due to its short curing time.

  In addition, since the pot life of the present invention is long, it is not easily influenced by the environmental temperature, is easy to use, and unlike the two-pack type epoxy resin, a stable cured product can be obtained.

  The main agent-primer type thermosetting epoxy resin of the present invention comprises (A) a primer composition and (B) a main agent composition.

  The (A) primer composition in the present invention contains one or more curing accelerating compounds selected from amine compounds and imidazole compounds. An amine compound and an imidazole compound are not limited as long as they can be used as curing accelerators for epoxy resins.

  Examples of the curing accelerating compound include lauryldimethylamine, dimethylcyclohexylamine, dimethylbenzylamine, dimethylaminomethylphenol, 2,4,6-tris (N, N-dimethylaminomethyl) phenol, 1,4-diazabicyclo [2.2. .2] Octane, 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU), 1,5-diazabicyclo [4,3,0] non-5-ene (DBN), 2-methyl Imidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2- Phenylimidazole, 1-benzyl-2-methylimidazole, 1-silane Noethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2,4-diamino-6- (2- Methylimidazolylethyl) -1,3,5-triazine, 2,4-diamino-6- (2-undecylimidazolylethyl) -1,3,5-triazine, 2,4-diamino-6- (2-ethyl) Examples include -4-methylimidazolylethyl) -1,3,5-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like. Preferred curing accelerators are 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU), 1,5-diazabicyclo [4,3 , 0] Non-5-ene (DBN). The curing accelerators may be used alone or in combination.

  In addition to the curing accelerating compound, the (A) primer composition in the present invention preferably contains a solvent capable of dissolving or dispersing the curing accelerator for the convenience of coating. The solvent is not limited as long as the curing accelerator is dissolved or dispersed, and examples thereof include acetone, alcohol, toluene, trichloroethane, methyl ethyl ketone, ethyl acetate, and normal hexane. Acetone is particularly preferable when the curing accelerator is a cyclic amine. . When the primer composition contains a solvent, a thin curing accelerator layer can be formed by evaporating the solvent.

  (A) In the primer composition, the ratio of curing accelerator: solvent can be appropriately selected so as to have a viscosity suitable for coating, but is preferably 0.1: 99.9 to 90:10 by weight ratio. Is 0.5: 99.5 to 50:50, particularly preferably 1:99 to 20:80.

  (A) The primer composition can be produced by mixing a curing accelerator and, if necessary, a solvent.

  The (B) main agent composition in the present invention includes (1) an epoxy resin having two or more epoxy groups in the molecule, and (2) a polythiol compound or acid anhydride having two or more thiol groups in the molecule.

  (1) The epoxy resin having two or more epoxy groups in the molecule only needs to have an average of two or more epoxy groups per molecule. For example, bisphenol A type epoxy resin, alkyl-substituted bisphenol A type Epoxy resin, bisphenol F type epoxy resin, alkyl-substituted bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, glycidyl ester type epoxy resin, urethane Examples thereof include, but are not limited to, modified epoxy resins, polysulfide-modified epoxy resins, rubber-modified epoxy resins, polyalkylene glycol type epoxy resins, and alicyclic epoxy compounds having a cyclic aliphatic group. These epoxy resins may be solid or liquid. Examples of the solid epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, and phenol novolac type epoxy resin. It is not necessarily limited to these. Epoxy resins may be used alone or in combination.

  (2) Polythiol compounds having two or more thiol groups in the molecule include, for example, 3,3′-dithiodipropionic acid, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene glycol Dithioglycolate, 1,4-bis (3-mercaptobutyryloxy) butane (trade name: Karenz MT (registered trademark) BD1 available from Showa Denko KK), tris [(3-mercaptopropionyloxy) -ethyl] -Isocyanurate (TEMPIC), 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (Showa Denko KK) Trade name: Karenz MT (registered trademark) NR1), Trimethylo Propane tris (3-mercaptopropionate) (TMMP), pentaerythritol tetrakis (3-mercaptopropionate) (PEMP), pentaerythritol tetrakis (3-mercaptobutyrate) (trade name: Karenz MT from Showa Denko KK) (Commercially available as (registered trademark) PE1), dipentaerythritol hexakis (3-mercaptopropionate) (DPMP), thiol compound obtained by esterification reaction of polyol and mercapto organic acid, 1,4-butanedithiol, 1 Alkyl polythiol compounds such as 1,6-hexanedithiol and 1,10-decanedithiol; terminal thiol group-containing polyether; terminal thiol group-containing polythioether; thiol obtained by reaction of epoxy compound with hydrogen sulfide A thiol compound having two or more thiol groups in the molecule such as a thiol compound having a terminal thiol group obtained by a reaction between a polythiol compound and an epoxy compound can be used. Preferred polythiol compounds are 1,4-bis (3-mercaptobutyryloxy) butane, tris [(3-mercaptopropionyloxy) -ethyl] -isocyanurate (TEMPIC), 1,3,5-tris (3-mercapto Butyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, trimethylolpropane tris (3-mercaptopropionate) (TMMP), pentaerythritol tetrakis (3- Mercaptopropionate (PEMP), pentaerythritol tetrakis (3-mercaptobutyrate), dipentaerythritol hexakis (3-mercaptopropionate) (DPMP). Polythiol compounds may be used alone or in combination.

  (2) Examples of acid anhydrides include hexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, 1-methylnorbornane-2,3-dicarboxylic anhydride 5-methylnorbornane-2,3-dicarboxylic acid anhydride, norbornane-2,3-dicarboxylic acid anhydride, 1-methylnadic acid anhydride, 5-methylnadic acid anhydride, nadic acid anhydride, phthalic acid anhydride Products, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, and terpene diene or triene compounds such as α-terpinene and alloocimene Diels-Alder reaction product with maleic anhydride, and unsaturated bond of these acid anhydrides Hydrogenated product of shall, including structural isomers or geometric isomers of these acid anhydrides, mixtures or modified products thereof are exemplified. Among them, acid anhydride curing agents that are liquid at room temperature by methods such as structural isomerization, geometric isomerization, and mixing of two or more of these acid anhydrides are exemplified. The acid anhydride may be a compound having two or more acid anhydride groups in the molecule, and examples of the compound include tetracarboxylic dianhydride, hexacarboxylic dianhydride, hexacarboxylic dianhydride, Polycarboxylic acid anhydrides such as maleic anhydride copolymer resin can be used. Specifically, as tetracarboxylic dianhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, Biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride, diphenyl sulfone tetracarboxylic dianhydride, diphenyl sulfide tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, perylene tetracarboxylic dianhydride, naphthalene tetra There are carboxylic dianhydrides. The acid anhydrides may be used alone or in combination.

  (B) In the main agent composition, the compounding ratio (molar ratio) of epoxy resin: polythiol compound is 70:30 to 30:70, preferably 60:40 to 40:60.

  (B) In the main agent composition, the compounding ratio (molar ratio) of epoxy resin: acid anhydride is 70:30 to 30:70, preferably 60:40 to 40:60.

  (B) When the main agent composition contains (1) an epoxy resin having two or more epoxy groups in the molecule and (2) a polythiol compound having two or more thiol groups in the molecule, the curing speed is high (B ) When the main agent composition contains (1) an epoxy resin having two or more epoxy groups in the molecule and an acid anhydride compound having two or more acid anhydrides in the molecule, the curing speed is slightly slow.

  Conventional components such as fillers, pigments and antioxidants can be added to the main agent-primer type thermosetting epoxy resin of the present invention within a range not impairing the effects of the present invention.

  (B) The main agent composition can be produced by mixing an epoxy resin, a polythiol compound or an acid anhydride, and, if necessary, conventional components.

  The main agent-primer type thermosetting epoxy resin of the present invention is in the form of a so-called kit in which the main agent composition and the primer composition are present respectively.

  The main agent-primer type thermosetting epoxy resin of the present invention may be a paint or an adhesive.

In the present invention, a primer composition containing one or more curing accelerating compounds selected from (A) an amine compound and an imidazole compound is applied to a substrate to obtain a primer coating layer, and (B) (1 After applying a main agent composition containing an epoxy resin having two or more epoxy groups in the molecule and (2) a polythiol compound or acid anhydride having two or more thiol groups in the molecule to obtain a main agent coating layer, The present invention also relates to a method for curing the main agent-primer type thermosetting epoxy resin, which includes heat-curing both coating layers.
Examples of the substrate include plastic, metal, glass, and ceramics.

Examples of the method for applying the primer composition to the substrate include application by dipping, application by brush or brush, application by dispenser or spray, and the like.
Examples of the method for applying the main agent composition include application by a dispenser, screen printing, and ink jet printing.

The amount of the primer composition applied to the main agent composition is not limited as long as both coating layers can be heat-cured, and can be easily set by those skilled in the art.
The heat curing of the coating layer can be performed by a conventional method using a thermostatic bath or a hot plate.

  The present invention applies (A) a primer composition containing one or more curing accelerating compounds selected from amine compounds and imidazole compounds to obtain a primer coating layer, and (B) (1) two epoxy groups in the molecule. The base resin composition containing the epoxy resin having the above and (2) a polythiol compound having two or more thiol groups in the molecule or an acid anhydride is applied to another substrate to obtain a base material coating layer, and then both coating layers are thermocompression bonded And curing the main agent-primer type thermosetting epoxy resin.

  Examples of the substrate include those described above, and one substrate and another substrate may be the same type of substrate or different substrates.

  The method of applying the primer composition to the substrate, the method of applying the main agent composition to the substrate, the application amount of the primer composition and the application amount of the main agent composition are the same as described above.

  The thermocompression bonding of the coating layer can be performed by a hot plate, a bonder, a hot press machine or the like.

  According to this method, curing in seconds can be performed by thermocompression bonding. Moreover, thick film hardening is also possible if the primer application layer and the main agent application layer are bonded together and sufficient time is allowed for the curing accelerator to penetrate into the main agent application layer before thermocompression bonding.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to an Example.

Example 1
50 parts by weight of bisphenol A type epoxy resin (YL7175-850S manufactured by Japan Epoxy Resin; epoxy equivalent of 184 to 194) and 35 parts by weight of trimethylolpropane tris (3-mercaptopropionate) (TMMP) are mixed to form a main composition. The product was manufactured (molar ratio epoxy resin: polythiol = 50: 50). Immediately after the production of the main agent composition, the viscosity was measured after standing at room temperature for 1 month and after standing at 40 ° C. for 1 month. The viscosities were immediately after production: 1013 mPa · s, after standing at room temperature for 1 month: 1033 mPa · s, and after standing at 40 ° C. for 1 month: 1317 mPa · s.

(Example 2)
50 parts by weight of a bisphenol A type epoxy resin (YL7175-860 manufactured by Japan Epoxy Resin; epoxy equivalent 235-255), tris [(3-mercaptopropionyloxy) -ethyl] -isocyanurate (TEMPIC), trimethylolpropane tris (3-mercaptopropionate) (TMMP), pentaerythritol tetrakis (3-mercaptopropionate) (PEMP), pentaerythritol tetrakis (3-mercaptobutyrate) or dipentaerythritol hexakis (3-mercaptopropionate) (DPMP) 35 parts by weight was mixed to produce a base composition. 96 parts of acetone and 4 parts by weight of 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU) or 1,5-diazabicyclo [4,3,0] non-5-ene (DBN) The primer composition was prepared by mixing.
As shown in FIG. 1, after applying a primer composition to an iron plate (25 × 70 × 0.5 mm) to a film thickness of 5 μm and applying an appropriate amount of the main agent composition to another iron plate (25 × 70 × 0.5 mm) The coated surfaces of the two iron plates were bonded together. Thereafter, the laminated iron plate was pressed against a hot plate (80 ° C.) to evaluate curability. The results are shown in Table 1.

(Example 3)
A main ingredient composition was produced in the same manner as in Example 1. A primer composition was prepared by mixing 4 parts by weight of 1,5-diazabicyclo [4,3,0] non-5-ene (DBN) and 96 parts by weight of acetone.
The primer composition is applied to an iron plate (25 × 70 × 0.5 mm) to a thickness of 5 μm, and an appropriate amount of the main agent composition is applied to another iron plate (25 × 70 × 0.5 mm), and then the two iron plates are coated. Were laminated with or without a spacer (thickness: 50, 100 or 300 μm). Thereafter, the bonded iron plate was pressed against a hot plate (60, 80 or 100 ° C.), and the time until curing was confirmed. The criterion for curing was the time when the iron plate stopped moving even when touched by hand. The results are shown in Table 2.

The uncured portion in Table 2 could be cured by leaving it at room temperature for a long time.

Example 4
The main agent composition and the primer composition were produced in the same manner as in Example 3. The primer composition was applied to the surface of the first nickel-plated steel plate (10 × 10 × 1 mm) to a thickness of 5 μm, and an appropriate amount of the main composition was applied to the surface of the second nickel-plated steel plate (15 × 15 × 3 mm). . After bonding the two coated surfaces, the first nickel-plated steel plate side was pressed against a hot plate at 100 ° C. for 10 seconds and cured to obtain a test piece. When the shear strength in the normal state of the test piece and the shear strength after heat shock (−40 ° C. × 30 minutes / 85 ° C. × 30 minutes) were measured, they were both 700 N or more (broken material).

  The present invention provides an epoxy resin that can be cured at a low temperature and can be cured for a short time, has an improved pot life, and provides a stable physical property of a cured product, and is therefore suitable for applications such as adhesives and paints. In addition, since the curing time is short, it can be applied to mass production.

A plan view (A), a side view 1 (B) and a side view 2 (C) of a test piece for measuring curability are shown.

Explanation of symbols

1: Iron plate 2: Spacer 3: Main agent composition + Primer composition

Claims (4)

(A) a primer composition for coating containing one or more curing accelerating compounds selected from amine compounds and imidazole compounds and having a viscosity suitable for coating ; and (B) (1) having two or more epoxy groups in the molecule. A main agent-primer type thermosetting epoxy resin adhesive comprising an epoxy resin and (2) a main agent composition containing a polythiol compound having two or more thiol groups in the molecule. The main agent-primer type thermosetting epoxy resin adhesive according to claim 1, wherein the curing accelerator is selected from cyclic amines. The polythiol compound is 1,4-bis (3-mercaptobutyryloxy) butane, tris [(3-mercaptopropionyloxy) -ethyl] -isocyanurate, 1,3,5-tris (3-mercaptobutyloxyethyl)- 1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol The main agent-primer type thermosetting epoxy resin adhesive according to claim 1 or 2, which is tetrakis (3-mercaptobutyrate) or dipentaerythritol hexakis (3-mercaptopropionate). (A) A primer composition containing one or more curing accelerating compounds selected from amine compounds and imidazole compounds is applied to a substrate to obtain a primer coating layer. (B) (1) Two or more epoxy groups in the molecule epoxy resin and (2) a main agent composition comprising a polythiol compound having two or more thiol groups in the molecule is coated on other substrate to obtain a base resin coating layer, and then both the coating layer and cured by thermocompression bonding with The adhesion | attachment method of the base material using the main ingredient-primer type thermosetting epoxy resin adhesive of any one of Claims 1-3 including adhere | attaching both base materials .