JP2017039832A - 2-cyanoacrylate-based adhesive composition containing tocopherol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 2-cyanoacrylate-based adhesive composition containing a polymerization inhibitor good in storage stability and high in safety under circumstance that hydroquinone mainly used as a radical polymerization inhibitor of a 2-cyanoacrylate-based adhesive composition currently is classified as a material with concern about carcinogenicity by FDA (Food and Drug Administration), there is possibility to have use limit due to recent environmental emission risk or the like and products with high safety are expected to be required in the future.SOLUTION: There is provided a 2-cyanoacrylate-based adhesive composition containing tocopherol of 1 to 1000 ppm, more preferably 5 to 100 ppm used together with an anionic polymerization inhibitor.SELECTED DRAWING: None

Description

The present invention relates to a 2-cyanoacrylate adhesive composition mainly composed of 2-cyanoacrylate.

A 2-cyanoacrylate adhesive composition containing 2-cyanoacrylic acid ester as a main component is widely used as an instantaneous adhesive in various industries such as electronics, electricity, automobiles, leisure field and general household.

The 2-cyanoacrylate adhesive composition has the advantage that it is a single solution and has a fast curing speed at room temperature, but during storage, it thickens even with weak anion species such as a small amount of moisture in the container. In addition to the problem of solidifying by radicals generated by light and heat from the outside.

Therefore, as an anionic polymerization inhibitor, for example, an inorganic acid, an organic acid, an acidic gas, borohydrofluoric acid or the like as described in Patent Document 1, Patent Document 2, and Patent Document 3 is added, and radical polymerization is performed. As the inhibitor, known substances such as hydroquinone, hydroquinone monomethyl ether, butylhydroxyanisole, and pyrogallol are used.

JP 49 94631 A Japanese Patent Laid-Open No. Sho 62100348 Japanese Patent Laid-Open No. 03 7786

However, the addition of certain radical polymerization inhibitors can result in a substantial delay in the cure rate. Furthermore, some general purpose stabilizers are already known to be toxic, mutagenic and carcinogenic.

Currently, hydroquinone, which is mainly used as a radical polymerization inhibitor for 2-cyanoacrylate adhesive compositions, is considered to be a carcinogenic substance by the FDA (Food and Drug Administration), and the environment in recent years. Since there is a possibility of usage restrictions due to emission risks, etc., highly safe items will be required in the future.

Therefore, the inventors of the present application have excellent storage stability by adding a highly safe tocopherol in combination with an anionic polymerization inhibitor in order to improve the storage stability of the 2-cyanoacrylate adhesive composition. It was found to obtain a 2-cyanoacrylate adhesive composition having

According to the 2-cyanoacrylate adhesive composition of the present invention, it is excellent in storage stability and high safety by adding tocopherol in an amount of 1 to 1000 ppm, more preferably 5 to 100 ppm in combination with an anionic polymerization inhibitor. An adhesive can be provided.

The 2-cyanoacrylate adhesive composition containing the tocopherol of the present invention will be described in detail below.

The 2-cyanoacrylate adhesive composition of the present invention has a tocopherol content of 1 to 1000 ppm, more preferably 5 with respect to the 2-cyanoacrylate adhesive composition containing an anionic polymerization inhibitor in 2-cyanoacrylate. It is a thing containing -100 ppm.

The 2-cyanoacrylate ester is methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, chloroethyl 2-cyanoacrylate, 2-cyanoacrylate n-propyl, 2-cyanoacrylate i-propyl, 2- Allyl cyanoacrylate, propargyl 2-cyanoacrylate, n-butyl 2-cyanoacrylate, i-butyl 2-cyanoacrylate, n-pentyl 2-cyanoacrylate, n-hexyl 2-cyanoacrylate, 2- Cyclohexyl cyanoacrylate, phenyl 2-cyanoacrylate, tetrahydrofurfuryl 2-cyanoacrylate, heptyl 2-cyanoacrylate, 2-ethylhexyl 2-cyanoacrylate, n-octyl 2-cyanoacrylate, 2-cyanoacryl 2-octyl acid, n-nonyl 2-cyanoacrylate, 2 Oxononyl cyanoacrylate, n-decyl 2-cyanoacrylate, n-dodecyl 2-cyanoacrylate, methoxyethyl 2-cyanoacrylate, methoxypropyl 2-cyanoacrylate, methoxyisopropyl 2-cyanoacrylate, 2-cyano Methoxybutyl acrylate, ethoxyethyl 2-cyanoacrylate, ethoxypropyl 2-cyanoacrylate, ethoxyisopropyl 2-cyanoacrylate, propoxymethyl 2-cyanoacrylate, propoxyethyl 2-cyanoacrylate, 2-cyanoacrylic acid Isopropoxyethyl, propoxypropyl 2-cyanoacrylate, butoxymethyl 2-cyanoacrylate, butoxyethyl 2-cyanoacrylate, butoxypropyl 2-cyanoacrylate, butoxyiso 2-cyanoacrylate Propyl, 2-cyanoacrylic acid butoxybutyl, 2-cyanoacrylic acid 2,2,2-trifluoroethyl and 2-cyanoacrylic acid hexafluoroisopropyl ester of isopropyl and the like. These 2-cyanoacrylic acid esters may be used alone or in combination of two or more.

Examples of anionic polymerization inhibitors include aliphatic sulfonic acids such as sulfur dioxide and methanesulfonic acid, aromatic sulfonic acids such as p-toluenesulfonic acid, trifluoride such as boron trifluoride methanol and boron trifluoride diethyl ether. Boron complexes, HBF4, trialkylborate, trifluoromethanesulfonic acid and the like can be mentioned. These can be used alone or in combination of two or more. A preferable addition amount is in the range of 1 to 10,000 ppm with respect to 2-cyanoacrylate.

The tocopherol used in the present invention specifically includes α-tocopherol (5,7,8-trimethyltocol), β-tocopherol (5,8-dimethyltocol), γ-tocopherol (7,8-dimethyltocol). ), Δ-tocopherol (8-methyltocol), and one or two of these may be used. As content, it is 1-1000 ppm, More preferably, it is 5-100 ppm. If it is less than 1 ppm, the storage stability will be poor, and if it exceeds 1000 ppm, it will be colored and not commercialized.

The tocopherol used in the present invention is a radical polymerization inhibitor conventionally used in combination with an anionic polymerization inhibitor, such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, catechol, pyrogallol, butylhydroxyanisole, gallic acid. Even when used in combination with propyl acid or the like, excellent effects can be obtained.

In the 2-cyanoacrylate adhesive composition of the present invention, a curing accelerator, a plasticizer, a colorant, a fragrance, a solvent, an adhesive strength improver, a thickener, an inorganic filler, etc. As long as the storage stability of the acrylate monomer is not impaired, it can be appropriately added and used.

Here, the curing accelerator refers to polyethylene glycol derivatives, calixarenes, crown ethers and the like.

Examples of the plasticizer here include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, 2-ethylhexyl phthalate, diisodecyl phthalate, trimethyl acetyl citrate, triethyl acetyl citrate, and tributyl acetyl citrate.

Examples of the thickener include polymethyl methacrylate (PMMA), acrylic rubber, polyester, polyvinyl chloride, polystyrene, cellulose ester, polyalkyl-α-cyanoacrylate, and ethylene-vinyl acetate copolymer.

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Evaluation method The adhesive composition after adjusting the storage stability test was filled in a 2 g polyethylene container, placed in a thermostat at 70 ± 2 ° C., and the state after 30 days was observed. The fluidity that was the same as the initial state was accepted, and the thickened, gelled, or cured product was rejected.

Appearance Test Similarly for the appearance test, a 2 g polyethylene container was filled with the adjusted adhesive composition, placed in a 70 ± 2 ° C. air circulation thermostat, and the state after 30 days was observed. Those without coloring were accepted, and those colored yellow to brown were rejected.

Synthesis example 1
88 g of paraformaldehyde, 170 g of toluene and 1.2 ml of piperidine are charged into a 1 L glass four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, and the temperature is raised while stirring. 300 g of ethyl cyanoacetate is added dropwise and dehydrated. After dehydration, 30 g of cresyl diphenyl phosphate and 10 g of phosphoric acid are added, and toluene is removed by distillation. 5 g of phosphoric anhydride is added and depolymerization is carried out at 200 ° C. at 10 mmHg. The depolymerized product was purified by vacuum distillation to obtain 250 g of ethyl 2-cyanoacrylate. 10 ppm of boron trifluoride etherate was added to ethyl 2-cyanoacrylate obtained here to prepare a 2-cyanoacrylate adhesive composition.

Example 1
1 ppm of α-tocopherol was added to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1 and mixed well. Table 1 shows the results of determination regarding the storage stability and appearance.

Examples 2-4
Α-tocopherol was added to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1 in the proportions shown in Table 1 and mixed well, and the results of determination of the storage stability and appearance were determined. Are shown in Table 1.

Examples 5-8 With respect to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, β-tocopherol was added at a ratio shown in Table 1 and mixed well, and these storage stability and Table 1 shows the results of the determination on the appearance.

Examples 9-12 With respect to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, γ-tocopherol was added at a ratio shown in Table 1 and mixed well, and these storage stability and Table 1 shows the results of the determination on the appearance.

Examples 13-16
With respect to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, α-tocopherol and β-tocopherol were mixed at a ratio of 1: 1 (weight ratio) at the ratio shown in Table 1. Table 1 shows the results of the determination regarding storage stability and appearance.

Comparative Example 1
Table 1 shows the results of determination of the storage stability and appearance of the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1.

Comparative Example 2
To the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, 0.5 ppm of α-tocopherol was added and mixed well, and the results of determination regarding storage stability and appearance are shown in Table 1.

Comparative Example 3 To the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, 1500 ppm of α-tocopherol was added and mixed well, and the results of determination regarding storage stability and appearance are shown in Table 1.

Comparative Example 4
To the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, 1500 ppm of β-tocopherol was added and mixed well, and the results of determination regarding storage stability and appearance are shown in Table 1.

Comparative Example 5 With respect to the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, 1500 ppm of γ-tocopherol was added and mixed well, and the results of determination regarding storage stability and appearance are shown in Table 1. .

Comparative Example 6 To the 2-cyanoacrylate adhesive composition obtained in Synthesis Example 1, 0.5 ppm of α-tocopherol and β-tocopherol mixed at a ratio of 1: 1 (weight ratio) was added. Table 1 shows the results of determination regarding storage stability and appearance after mixing thoroughly.

From the results shown in Table 1, both α-tocopherol, β-tocopherol, γ-tocopherol alone and α-tocopherol and β-tocopherol mixtures of Examples 1 to 16 were stable without coloration within the range of addition amount of 1 to 1000 ppm. The property was also good.
On the other hand, as in Comparative Examples 2 and 6, when the addition amount is less than 1 ppm, the storage stability deteriorates, and when it exceeds 1000 ppm as in Comparative Examples 3 to 5, the product cannot be provided as a product.

The 2-cyanoacrylate adhesive composition of the present invention uses a highly safe tocopherol, is excellent in storage stability, and has no coloration. The adhesive composition which does not receive can be provided.

Claims (2)

A 2-cyanoacrylate adhesive composition containing tocopherol. The 2-cyanoacrylate-based adhesive composition according to claim 1, comprising 1 to 1000 ppm of tocopherol, more preferably 5 to 100 ppm.