JPH0455468B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an instant adhesive composition that is used for bonding various materials in the fields of automobiles, machinery, electrical equipment, electronics, plastics, rubber, furniture, musical instruments, etc. [Prior art] Instant adhesives used for the above purposes are generally 2
- a cyanoacrylic acid ester with a polymer as a thickener and an anionic polymerization inhibitor as a polymerization inhibitor;
It is formulated with a radical polymerization inhibitor, and can obtain strong adhesive strength when bonding plastics, rubber, wood, etc., but it is not suitable for bonding metals or ceramics, or when stress is applied such as peeling or impact. Adhesive force was insufficient for adhering the parts. As a method to improve the drawbacks of instant adhesives that are weak against peeling and impact forces, for example,
As seen in Publication No. 47471 and US Patent No. 4425471, 2-cyanoacrylic acid ester,
Attempts to incorporate 2-cyano-2,4-pentadienoic acid ester are known. In addition, as a method for improving the adhesion speed and storage stability of 2-cyanoacrylate-based instant adhesives, for example, as shown in JP-A-48-630, the water content in the adhesive is reduced to 50 to 200 ppm. It has been known that the lower the moisture content of this type of instant adhesive, the better the storage stability and the better the adhesive performance. [Problems to be solved by the invention] However, 2-cyano-acrylic acid ester is added to 2-cyano-acrylic acid ester for the purpose of improving peeling and impact strength.
The above-mentioned adhesive composition containing 2,4-pentadienoic acid ester has a slower adhesion speed than conventional adhesives and has extremely poor storage stability; it can only be stored stably for about one month at room temperature. Can not do it. In view of the current situation, the inventors have made efforts to improve the adhesion speed and storage stability of an impact-resistant adhesive composition containing 2-cyanoacrylic acid ester and 2-cyano-2,4-pentadienoic acid ester. As a result of our research, we found that it is extremely effective to select a specific 2-cyanoacrylic acid ester and to control the amount of water in the adhesive composition in order to solve the problems of adhesion speed and storage stability. We have developed a practical impact-resistant instant adhesive of the present invention which has an adhesion speed that sets within several tens of seconds and has a storage stability of at least half a year. [Means for Solving the Problems] The adhesive composition of the present invention has an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group.
- 1 to 100 parts by weight of 2-cyanoacrylate () mainly composed of alkyl cyanoacrylate or cycloalkyl ester, and 2-cyano-2,4-pentadienoate ()
It is characterized by containing 200 parts by weight of a polymerization inhibitor () consisting of an anionic polymerization inhibitor and a radical polymerization inhibitor (200 to 10,000 ppm each) and 200 to 10,000 ppm of water (200 to 10,000 ppm), and in particular contains water (200 to 10,000 ppm). The amount ranges from 200 to 10000ppm (more preferably
The adhesive controlled at a concentration of 300 to 5000 ppm has extremely good adhesive performance and exhibits excellent storage stability. [Function] In general, 2-cyanoacrylate-based instant adhesives do not pose any practical problems when stabilized with a polymerization inhibitor. Then, the moisture content in the adhesive composition is adjusted to 50~
As mentioned above, it is known that the performance of the adhesive can be further improved by controlling the content within the range of 200 ppm. However, instant adhesives containing a mixture of 2-cyanoacrylic acid ester and 2-cyano-2,4-pentadienoic acid ester have poor storage stability and poor adhesion speed even when stabilized with a polymerization inhibitor. Become slow. Since 2-cyano-2,4-pentadienoic acid ester is an extremely unstable monomer, it is presumed that this phenomenon occurs due to some kind of interaction between it and 2-cyanoacrylic acid ester. This phenomenon can be solved by using an alkyl 2-cyanoacrylate or cycloalkyl ester having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group as an impact-resistant instant adhesive composition, and adding a polymerization inhibitor thereto. This problem could be solved by containing a certain range of moisture, and the reason for this is 2-
It is presumed that this is because the hydrate of the polymerization inhibitor has a specific stabilizing effect on cyano-2,4-pentadienoic acid ester, and this certain range of moisture is extremely effective as a curing reaction initiator during adhesion. acts on,
It is thought that this increases the adhesion speed. The components constituting the adhesive composition of the present invention will be explained below. [2-cyanoacrylic ester] The 2-cyanoacrylic ester used in this invention has an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group, and
This range includes all those commonly used in instant adhesives. 2- having the above-mentioned alkyl group having 1 to 6 carbon atoms
Cyanoacrylic acid alkyl esters include methyl, ethyl, n-propyl, isopropyl, n
Examples include alkyl esters such as -butyl, i-butyl, s-butyl, n-pentyl, and n-hexyl, and particularly preferred are methyl, ethyl, butyl, and propyl in which the alkyl group has 1 to 4 carbon atoms. Furthermore, as for 2-cyanoacrylic acid cycloalkyl ester having a cycloalkyl group, when the number of carbon atoms in the cycloalkyl group exceeds 13, the storage stability and adhesion speed of the adhesive composition tend to decrease. Therefore, those having 12 or less carbon atoms are preferable, and specific examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl, cyclododecyl, and methylcyclohexyl. 2-cyanoacrylic acid alkyl ester is poor in the effect of improving storage stability when used in combination with 2-cyano-2,4-pentadienoic acid ester, and cannot be used as a substantially practical instant adhesive. However, the above-mentioned 2-cyanoacrylic acid alkyl ester having 1 to 6 carbon atoms and 2-cyanoacrylic acid cycloalkyl ester having a cycloalkyl group are the main components of the 2-cyanoacrylic acid ester in this invention. , if these are substantially the majority, 2-cyanoacrylic acid alkyl esters having a small amount of alkyl groups having 7 or more carbon atoms and other 2-cyanoacrylic acid esters, such as allyl, heptyl, n-octyl , 2-ethylhexyl, nonyl, decyl, n-
dodecyl, 2-chloroethyl, propargyl, 2-
There is no problem in using methoxyethyl, 2-ethoxyethyl, 3-methoxybutyl, 2-methoxypropyl, trifluoroethyl, etc. in combination. [2-Cyano-2,4-pentadienoic acid ester] The 2-cyano-2,4-pentadienoic acid ester used in this invention is an ester of monohydric alcohol, and the group constituting the ester is specifically , methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, i-butyl, s-butyl, n-pentyl, n-hexyl, cyclohexyl, heptyl, n-octyl, 2-ethylhexyl, nonyl, decyl, n -dodecyl, 2-chloroethyl, 2-methoxyethyl, 2-ethoxyethyl, 3-methoxybutyl, 2-methoxypropyl, trifluoroethyl, etc. Among the esters of the monohydric alcohols, especially methyl and ethyl , propyl, hexyl and the like are preferred. [Polymerization inhibitor] The polymerization inhibitor used in this invention includes all the polymerization inhibitors used in conventional instant adhesives, and the anionic polymerization inhibitors include:
Specifically, sulfur dioxide gas (SO ₂ ), sulfuric anhydride (SO ₃ ), chlorosulfonic acid, methanesulfonic acid,
benzenesulfonic acid, p-toluenesulfonic acid,
Examples include trifluoromethanesulfonic acid, trifluoroacetic acid, propane sultone, hexafluoroacetone, trifluoroacetaldehyde, pentafluorophenol, and among these, acidic compounds are particularly effective and preferred. Examples of the radical polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol, t-butylhydroquinone, 2,6-di-t-butyl-1-hydroxytoluene, and bisphenol-A. Next, the manufacturing conditions for the adhesive composition of the present invention will be explained. For 100 parts (parts by weight; the same applies hereinafter) of a 2-cyanoacrylate () mainly consisting of an alkyl or cycloalkyl 2-cyanoacrylate having an alkyl group or a cycloalkyl group having 1 to 6 carbon atoms, 2- 1 to 200 parts, preferably 5 to 100 parts, more preferably 10 to 50 parts of cyano-2,4-pentadienoic acid ester () are blended. Specifically, for example, 2 parts per 100 parts of ester such as methyl, ethyl, propyl, butyl, or cyclohexyl ester of 2-cyanoacrylic acid.
- 1 to 200 parts of cyano-2,4-pentadienoic acid ester such as methyl, ethyl, butyl, propyl, hexyl, etc. are blended. In this case, when the amount of 2-cyano-2,4-pentadienoic acid ester () is less than 1 part, no improvement in peeling or impact strength is observed, and when it exceeds 200 parts, there is a tendency for the adhesion speed to slow down. . On the other hand, the polymerization inhibitor () is an anionic polymerization inhibitor and a radical polymerization inhibitor, respectively.
Add 10,000 ppm, preferably 5 to 2,000 ppm. If each of these polymerization inhibitors is less than 1 ppm, the desired polymerization prevention effect cannot be achieved,
When added in a large amount exceeding 10,000 ppm, the polymerization prevention effect becomes excessive and inhibits the adhesive effect during use. Moisture content is 200 to 10,000 ppm, preferably 300 to 10,000 ppm
Mix to make it 5000ppm. This may be added as water or may be simultaneously added as a solvent for the anionic polymerization inhibitor and mixed by stirring. In this case, if the water content is less than 200 ppm, the storage stability of the adhesive will be extremely low, and it will easily thicken or gel.
If the water content exceeds 10,000 ppm, storage stability will be poor, and viscosity increase, gelation, or deterioration of adhesion speed over time will become significant. However, usually the 2-
Cyanoacrylic acid ester (), 2-cyano-
Charge 2,4-pentadienoic acid ester (), polymerization inhibitor () and water into a mixer and mix from 0 to 60
It is made into an adhesive by stirring until it becomes uniform under temperature conditions in the range of °C. In this invention, conventional instant adhesive manufacturing technology is applied. For example, in order to impart viscosity to the adhesive, polymers such as acrylic esters, methacrylic esters, acrylonitrile/butadiene, and cellulose-based adhesives are used. A few percent of the derivative may be added as a thickener. In addition, plasticizers are added to give flexibility to the cured product produced by adhesion, and reinforcing agents such as polycarboxylic acid and polycarboxylic acid anhydride are added to improve adhesive strength. A latent curing accelerator such as a polyethylene glycol compound may also be added to increase the adhesion speed. In addition, dyes and pigments for coloring, organic or inorganic fillers for imparting thixotropy, such as gelol (trade name of Shin Nihon Rika Co., Ltd.), finely powdered silica, alumina, titanium oxide, etc., and hardening A few percent of fibers, powder, whiskers, etc. may be added to strengthen the material. [Examples] Examples of the adhesive composition of the present invention are shown below. Example 1 2-cyanoacrylic acid ester (), 2-cyano-2,4-pentadienoic acid ester (),
An adhesive composition (viscosity 5 cp) was prepared by mixing a polymerization inhibitor () and water () in the proportions shown below at a temperature of 20°C for 1 hour until uniform.
I got it. (1) Ethyl 2-cyanoacrylate 80 parts (2) Ethyl 2-cyano-2,4-pentadienoate
20 parts (3) SO ₂ 50ppm (4) Hydroquinone 1000ppm (5) Water 1000ppm Next, the adhesive obtained by the above method was
The results of evaluating adhesive performance according to K6861 were as follows. Set time (Hard PVC) 5 seconds Same (Iron) 10 seconds Tensile shear adhesive strength (Iron) 230Kgf/cm ² Impact peeling adhesive strength (Iron) 18Kgf・cm/cm ² Peeling adhesive strength (Iron) 7Kgf/25mm (The thickness of the iron in each case above is 300 μt) Heat stability test: No change (Polyethylene container, 60°C x 10 days) From the above results, it can be seen that this adhesive has storage stability for more than 6 months at room temperature. Examples 2 to 11 In the same manner as in Example 1, 2-cyanoacrylic acid ester (), ethyl 2-cyano-2,4-pentadienoate (), polymerization inhibitor (), etc. were blended to prepare an adhesive. did. Table 1 shows these compositions and the results of performance evaluation.

【table】

[Table] Comparative Examples 1 to 4 Comparison of various combinations of 2-cyanoacrylic acid ester (2), ethyl 2-cyano-2,4-pentadienoate (2), polymerization inhibitor (2), etc. outside the scope of this invention The adhesives of Examples 1-4 were prepared. The compositions and performance evaluation results are shown in Table 2.

【table】

〔Effect of the invention〕

The adhesive composition of the present invention can significantly improve the drawbacks of conventional instant adhesives, namely poor impact and peel strength.
-cyanoacrylic acid ester and 2-cyano-
The problem of slow adhesion speed and poor storage stability of mixed adhesives with 2,4-pentadienoic acid esters has also been solved. It is possible to provide a practical instant adhesive that has both the above properties and storage stability.

Claims (1)

[Claims] 1 Mainly composed of alkyl 2-cyanoacrylate or cycloalkyl ester having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group
-1 to 200 parts by weight of 2-cyano-2,4-pentadienoic acid ester () to 100 parts by weight of cyanoacrylic ester (2), respectively 1 to 200 parts by weight of 2-cyano-2,4-pentadienoic acid ester (2)
Polymerization inhibitor () consisting of 10000ppm anionic polymerization inhibitor and radical polymerization inhibitor and 200~
An adhesive composition characterized by being blended with 10,000 ppm of water ().