JP3786482B2 - Curing agent and curing method for 2-cyanoacrylate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inner-contained curing agent for mixing therewith prior to use of the 2-cyanoacrylate. The present invention also relates to a curing method using the internally added curing agent .
[0002]
[Prior art]
Instant adhesives based on 2-cyanoacrylate have a fast curing property and are widely used as industrial and household adhesives. 2-Cyanoacrylate may be used as a coating agent or filler (in the form of a thin film) in addition to being used as an adhesive.
[0003]
When 2-cyanoacrylate is applied to an object, if the object is a nonpolar material such as polyethylene, polypropylene, polyacetal, or ethylene-propylene-diene terpolymer, the desired adhesion tends not to be obtained. is there. In such a case, the surface of the object is previously treated with a primer in which an inorganic basic substance, an organic basic substance, an organometallic compound, a phosphite, a diazabicyclo compound, etc. are dissolved in a readily volatile solvent, After the primer is dry, 2-cyanoacrylate is applied to the treated surface.
[0004]
A few applications for 2-cyanoacrylate primers are described in Japanese Patent Application Laid-Open No. 62-18485, which is filed by the present applicant, with 2,4-lutidine, 3,4-lutidine, and 6-amino-2. A primer for 2-cyanoacrylate-based instant adhesives comprising a compound selected from the group consisting of picoline, 4-dimethylaminopyridine, 2-aminopyridine, 3-aminopyridine and 1-vinylimidazole or a solvent solution thereof is shown. ing. Similarly, Japanese Patent Application Laid-Open No. 62-18486, filed by the present applicant, discloses a compound containing 4-vinylpyridine as an essential component and β-picoline or / and 3,4-lutidine as an optional component or a solvent solution thereof. A primer for a 2-cyanoacrylate instant adhesive is shown. In these publications, various introductions are also made on the primers proposed prior to the application.
[0005]
Japanese Patent Application Laid-Open No. 6-57218 relating to the applicant's application discloses a primer for a 2-cyanoacrylate-based instantaneous adhesive containing a trialkylamine, particularly trilaurylamine as an active ingredient. This publication also introduces various types of primers that have been proposed prior to the application.
[0006]
[Problems to be solved by the invention]
Since 2-cyanoacrylate is primarily one that begins anionic polymerization due to moisture in the air and begins to cure, when it is used as an adhesive or as a coating agent or filler, it becomes a thin film. If it is not applied to the object, the surface will not harden even if the surface is hardened, or the strength will not be obtained even if it is finally hardened over a long time. In addition, a thick and slow-curing portion such as a portion that protrudes during bonding tends to cause a whitening phenomenon. This whitening phenomenon is because 2-cyanoacrylate as a monomer volatilizes in the air around the application site, is cured by moisture in the air, and accumulates at the application site.
[0007]
Therefore, 2-cyanoacrylate has a thick adhesion layer, manufacture of a molded product having a certain thickness or more, filling in a portion having a wide gap, application of a thick film in a putty shape, coating of a thick film of a target article. It was difficult to use it. Such usage is originally not suitable for 2-cyanoacrylate.
[0008]
However, the quick curing property of 2-cyanoacrylate and the transparency and hardness of cured 2-cyanoacrylate are attractive. If 2-cyanoacrylate can be cured quickly even if it is thick or thick, It is possible to expand to applications that could not be applied.
[0009]
Therefore, the present inventors considered adopting a conventional primer method when obtaining a thick film or a thick 2-cyanoacrylate cured product, and the object surface was treated with a primer, and after the primer was dried, Although examination was conducted on the application of 2-cyanoacrylate to the treated surface, only the interface contacting with the primer treated surface and the surface contacting with air are rapidly cured, and the interior is not easily cured. Faced a problem.
[0010]
In addition, the present inventors also examined the application of a conventional primer from the uncured 2-cyanoacrylate applied to the thick film, but only the surface of the thick film was cured rapidly, The inside of the thick film did not harden easily.
[0011]
Furthermore, the present inventors also examined adding a small amount of an anionic polymerization accelerator such as an amine compound to 2-cyanoacrylate as it is or dissolved in a solvent. It was difficult to obtain a product having
[0012]
Under such a background, the present invention provides a curing agent that can be cured quickly even when 2-cyanoacrylate is applied thick or thick, and can effectively suppress whitening. It is an object of the present invention to provide a method for curing 2-cyanoacrylate using the curing agent.
[0013]
[Means for Solving the Problems]
<Curing agent of the present invention / internally added curing agent>
The curing agent for 2-cyanoacrylate according to the present invention is an internal curing agent for mixing with 2-cyanoacrylate prior to the use of 2-cyanoacrylate, and the internal curing agent is
Comprising a composition in which an anionic polymerization accelerator (B) is mixed in a medium (A) comprising a plasticizer (a1) compatible with 2-cyanoacrylate or a solvent (a2) , and
The proportion of the anionic polymerization accelerator (B) in the composition is 0.001 to 10% by weight,
It is characterized by.
[0014]
<Curing method of the present invention >
The curing method of the present invention is characterized in that prior to the use of 2-cyanoacrylate, the above-mentioned internal additive-type curing agent is mixed with it, and then 2-cyanoacrylate mixed with the internal-addition-type curing agent is used. To do.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
[0016]
<2-cyanoacrylate>
Examples of 2-cyanoacrylate include alkyl 2-cyanoacrylate, cycloalkyl 2-cyanoacrylate, alkoxyalkyl 2-cyanoacrylate, alkenyl 2-cyanoacrylate, alkynyl 2-cyanoacrylate, and the like. Of these, examples of alkyl 2-cyanoacrylate include methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, various propyl 2-cyanoacrylates, various butyl 2-cyanoacrylates, various pentyl 2-cyanoacrylates, and various hexyl 2-cyano. Examples of alkoxyalkyl 2-cyanoacrylates include ethoxyethyl 2-cyanoacrylate, methoxyethyl 2-cyanoacrylate, methoxyisopropyl 2-cyanoacrylate, and the like.
[0017]
2-Cyanoacrylate is a polymerization inhibitor, a stabilizer, a thickener, a heat resistance imparting agent, a plasticizer, a colorant, a thixotropy improver, a pH adjuster, ethylene carbonate, an organic solvent, a filler, a polymer, if necessary. Etc. may be included.
[0018]
<Internal addition type curing agent>
The internally added curing agent of the present invention has a composition in which an anionic polymerization accelerator (B) is mixed in a plasticizer (a1) compatible with 2-cyanoacrylate or a medium (A) comprising this and a solvent (a2). It consists of things.
[0019]
Here, as the plasticizer (a1), phthalic acid esters such as dibutyl phthalate, dioctyl phthalate, diallyl phthalate, butyl benzoyl phthalate; butyl benzyl phosphate, dibutyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, Phosphate esters such as xylenyl diphenyl phosphate; halogen-containing phosphate esters such as tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (β-chloropropyl) phosphate; adipate esters such as dibutyl adipate and dioctyl adipate Sebacic acid esters such as dimethyl sebacate, dibutyl sebacate, dioctyl sebacate; dipropylene glycol dibenzoate, neopentyl Recall dibenzoate, glycerin tribenzoate, benzoic acid esters such as pentaerythritol benzoate; including, plasticizer having a 2-cyanoacrylate compatible is used.
[0020]
Examples of the solvent (a2) include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), aliphatic, alicyclic or aromatic hydrocarbons (n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene, etc.), Esters (methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, isoamyl acetate, etc.), ethers (dioxane, diethyl ether, diisopropyl ether, di-n-propyl ether, etc.), halogen-containing solvents (methylene chloride, perchlorethylene) 1,1,1-trichloroethane, trichloroethylene, chloroform, methyl chloroform, carbon tetrachloride, etc.), cellosolve (methyl cellosolve, cellosolve acetate, etc.), nitrogen-containing solvents (nitromethane, nitroethane, etc.), nitrogen-containing solvents, 2- Cyanoa A solvent that does not react with acrylate and is compatible with 2-cyanoacrylate is used.
[0021]
The medium (A) uses only the plasticizer (a1) or the plasticizer (a1) and the solvent in order to prevent the pot life from being shortened beyond the allowable limit and to reduce the volume shrinkage after curing. Use in combination with (a2).
[0022]
Examples of the anionic polymerization accelerator (B) include inorganic basic substances such as sodium hydroxide and potassium hydroxide; organic basic substances (N, N-dimethylaniline, N, N-dimethyl-p-toluidine, N, N-dimethyl-m-toluidine, N, N-dimethyl-o-toluidine, N, N-diethyl-m-toluidine, N, N-diethyl-p-toluidine, N, N, N ′, N′-tetraethylethylenediamine , O-phenylenediamine, trichloroacetamide, succinimide, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, ethylamine, diethylamine, triethylamine, trilaurylamine, isopropylamine, butylamine, tributylamine, monoethanolamine , Diethanolamine, triethanol Min, pyrroline, dimethylbenzylamine, ethylenediamine, hexamethylenediamine, lutidine, picoline, 6-amino-2-picoline, pyridine, 2-vinylpyridine, 2,6-dichloropyridine, 4-dimethylaminopyridine, 2-amino Organic basic substances such as pyridine, 3-aminopyridine, 1-vinylimidazole, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, diaminophenylmethane; organometallic compounds such as aluminum sec-butoxydiisopropylate Phosphite compounds such as bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite; phosphites; organic phosphine compounds; diazabicyclo compounds; aldehyde aniline compounds; phosphate or phosphite-containing organic titanium compounds ; And the like.
[0023]
The proportion of medium anionic polymerization accelerator occupied in composition mixed anionic polymerization accelerator (B) in (A) (B) is set to 0.001 to 10 wt%. A preferred range is about 0.01 to 5% by weight . When the proportion is too small, the physical properties of the 2-cyanoacrylate cured product change, while the proportion is too large, because a large amount must be mixed with 2-cyanoacrylate to obtain the required curing acceleration. Is difficult to control the amount of internal addition when mixed with 2-cyanoacrylate.
[0024]
< Curing method>
The internal addition type curing agent is mixed with the 2-cyanoacrylate prior to the use of 2-cyanoacrylate, and then 2-cyanoacrylate mixed with the internal addition type curing agent is used. The pot life from mixing to use varies depending on the type of 2-cyanoacrylate and the type and amount of the anionic polymerization accelerator (B), but is adjusted, for example, from several tens of seconds to about 2 hours.
[0025]
The mixing ratio of the internal curing agent with respect to 100 parts by weight of 2-cyanoacrylate is 0.01 to 20 parts by weight, especially 0.1 to 5 parts by weight, based on the composition (medium (A) + anionic polymerization accelerator (B)). In terms of the anionic polymerization accelerator (B), 0.0001 to 3 parts by weight, particularly 0.001 to 1 part by weight is appropriate. When the ratio of the composition or the anionic polymerization accelerator (B) is too small, the action of promoting the curing of 2-cyanoacrylate is insufficient, while when the ratio is too large, it can be used when mixed with 2-cyanoacrylate. Time becomes extremely short and lacks practicality.
[0026]
<Action>
In the curing agent of the present invention, not only the anionic polymerization accelerator (B) but also the plasticizer (a1) in the medium (A) plays an important role. That is, since the anionic polymerization accelerator (B) is mixed with 2-cyanoacrylate in a state protected with the medium (A) (plasticizer (a1) or this and the solvent (a2)), the pot life after mixing is increased. Secured .
[0027]
If the curing method according to the above method is carried out using the curing agent of the present invention, even if 2-cyanoacrylate is applied thick or thick, it can be cured quickly and the whitening phenomenon is effectively suppressed. can do. The whole is cured even under low temperature conditions. Therefore, it becomes possible to use 2-cyanoacrylate as exemplified below, which could not be conventionally expected.
[0028]
(I) Thick or three-dimensional molded product utilizing the characteristics of 2-cyanoacrylate, such as high hardness, transparency, and chemical resistance. 2-Cyanoacrylate has a low viscosity and is difficult to contain bubbles. Thus, a molded product having an arbitrary shape can be obtained. Expensive order parts and emergency repair parts can be manufactured using high hardness. A decorative article making use of transparency is also preferable, and the refractive index of the cured product is close to the refractive index of glass, so that it can be suitably used for parts for which glass is conventionally used.
[0029]
(B) Repairing agent, reinforcing agent, injecting agent By making it a type that can be colored and cut, various fillings such as flooring can be repaired. Even a large hole that does not harden with normal 2-cyanoacrylate, or a hole that does not harden and enter with 2-cyanoacrylate by a conventional primer method, can be applied. It is also possible to fill a crack or the like having a large gap.
[0030]
(C) Adhesive A thick adhesive layer that was impossible in the past is also possible.
[0031]
(D) Putty It is possible to apply a thick film with a putty shape.
[0032]
(E) Coating agent, painting agent, sealing agent, sealing agent Thick film can be applied. Moreover, it can be used to cover and seal the entire material. For example, when at least one of the adherends is made of metal, the strength may deteriorate due to oxidation of the metal. However, if the adhesion is performed by covering and sealing the entire metal, the strength will be prevented from deteriorating. can do. It is also recommended to use methyl 2-cyanoacrylate, which has good chemical resistance and is particularly resistant to acidic solvents. It is also advantageous when painting on a glass with a close refractive index.
[0033]
【Example】
Next, the present invention will be described in more detail with reference to examples. Hereinafter, “%” refers to weight%.
[0034]
Example <Preparation of materials>
As 2-cyanoacrylate (abbreviated as 2-CA), methyl 2-cyanoacrylate (abbreviated as M-CA), ethyl 2-cyanoacrylate (abbreviated as E-CA), isobutyl 2-cyanoacrylate (abbreviated as IB-CA) ), Ethoxyethyl 2-cyanoacrylate (abbreviated as EE-CA).
[0035]
Among the media (A), as a plasticizer (a1), tris (chloroethyl) phosphate (abbreviated as CLP), dibutyl phthalate (abbreviated as DBP), dioctyl phthalate represented by the formula (O) P (OCH ₂ CH ₂ Cl) ₃ (Abbreviated as DOP) and, as the solvent (a2 ) in the medium (A) , readily volatile acetone (Ace) and slow volatile methyl isobutyl ketone (MIBK) were prepared.
[0036]
As an anionic polymerization accelerator (B), N, N-dimethylaniline (abbreviated as DMA), N, N-dimethyl-p-toluidine (abbreviated as DMpT), N, N-diethyl-m-toluidine (abbreviated as DEmT) Ethylenediamine (abbreviated as EDA) was prepared.
[0037]
<Preparation of internal curing agent >
A small amount of the anionic polymerization accelerator (B) was dissolved in the above-mentioned medium (A) to prepare an internally added curing agent comprising a 0.2%, 0.5% or 1.0% concentration solution.
[0038]
< Curing method>
To the polyethylene container containing 10 g of the above-mentioned 2-cyanoacrylate, 0.6 g of the above-mentioned internal curing agent was added, and the container was shaken well and mixed. Next, 2-cyanoacrylate mixed with this internally added curing agent was poured into a polyethylene mold at a depth of 4 mm from a nozzle attached to the container and allowed to stand until cured. For comparison, an experiment was also conducted for the case where no internal curing agent was mixed. The conditions and results are shown in Table 1. In Table 1, “DBP + Ace” of 1d is a 4: 1 mixture of DBP and Ace, and “CLP + MIBK” of 2d is a 1: 1 mixture of CLP and MIBK.
[0039]
[Table 1]

Appearance of inner-contained curing agent composition 2-CA curing time cured product of
No. (A) (B) and concentration type surface inside (transparency, unevenness, whitening)
1a CLP DMA 0.2% E-CA 4.5min 4.5min Transparent, smooth, no whitening
1b DBP DEmT 1.0% E-CA 12 min 12 min Transparent, smooth, no whitening
1c DOP DMpT 0.2% E-CA 2.5min 2.5min Transparent, smooth, no whitening
1d DBP + DMpT 0.5% E-CA 20 min 20 min Transparent, smooth, no whitening
Ace
1 ' - - - E-CA (it will not harden indefinitely)
2a CLP DMA 0.2% M-CA 2 min 2 min Transparent, smooth, no whitening
2b DBP DEmT 1.0% M-CA 1 min 1 min Transparent, smooth, no whitening
2c DOP DMpT 0.2% M-CA 2.5min 2.5min Transparent, smooth, no whitening
2d CLP + EDA 0.5% M-CA 10 min 10 min Transparent, smooth, no whitening
MIBK
2 ' - - - M-CA (Don't set any time)
3a CLP DMA 0.2% IB-CA 5 min 5 min Transparent, smooth, no whitening
3b DBP DEmT 1.0% IB-CA 15 min 15 min Transparent, smooth, no whitening
3c DOP DMpT 0.2% IB-CA 3 min 3 min Transparent, smooth, no whitening
3 ' - - - IB-CA (it will not harden forever)
4a CLP DMA 0.2% EE-CA 60 min 60 min Transparent, smooth, no whitening
4b DBP DEmT 1.0% EE-CA 20 min 20 min Transparent, smooth, no whitening
4c DOP DMpT 0.2% EE-CA 10 min 10 min Transparent, smooth, no whitening
Four - - - EE-CA (it will not harden indefinitely)
[0040]
When a 0.2% or 1.0% concentration solution in which triethanolamine, DMA, or DMpT is dissolved in ECA is used as an internal curing agent that does not contain a plasticizer, the pot life is extremely short and practical. Did not have.
[0041]
< Curing method / Example of injection into hole >
A hole with a diameter of 1 mm and a depth of 10 mm was drilled in the oak, and into the hole, an internally added curing agent mixed ethyl 2-cyanoacrylate having the same formulation as No. 1a in Table 1 was injected from the nozzle of the container. The injection was completely cured after about 5 minutes. Incidentally, when only ethyl 2-cyanoacrylate was injected, it was not completely cured even after 10 hours. In addition, a commercially available primer (N, N-dimethylaniline in 1% acetone) was sprayed into the hole in advance, and then only ethyl 2-cyanoacrylate was tried to be injected. Hardened and could not be injected deep into the hole.
[0042]
【The invention's effect】
If the above curing method is carried out using the curing agent of the present invention, even if 2-cyanoacrylate is applied thick or thick, the inside can be cured quickly and the whitening phenomenon can be effectively suppressed. Can do. The whole is cured even under low temperature conditions. Therefore, 2-cyanoacrylate can be used in the production of molded products, injection and curing to areas with wide gaps, thick adhesion of adhesive layers, and thick films as putty / coating / painting / sealing / sealing agents. It is possible to use various methods such as the application of which has not been expected in the past.

Claims (2)

An internal addition type curing agent for mixing with 2-cyanoacrylate prior to use, the internal addition type curing agent,
Comprising a composition in which an anionic polymerization accelerator (B) is mixed in a medium (A) comprising a plasticizer (a1) compatible with 2-cyanoacrylate or a solvent (a2) , and
The proportion of the anionic polymerization accelerator (B) in the composition is 0.001 to 10% by weight,
A curing agent for 2-cyanoacrylate.   A curing method comprising mixing the internal addition type curing agent of claim 1 prior to the use of 2-cyanoacrylate, and then using the mixed 2-cyanoacrylate with the internal addition type curing agent.