JP2569742B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Object of the Invention [Industrial Application Field] The present invention relates to a cyanoacrylate-based adhesive having an adhesive portion having an appropriate flexibility and an adhesive strength that can be used temporarily. The present invention relates to an adhesive composition and expands the use of a cyanoacrylate-based adhesive which has been widely used as an instant adhesive, and can be used in various fields.

[Conventional technology]

BACKGROUND ART Cyanoacrylate-based adhesives are used in a wide range of fields such as industrial use, general household use, and medical use as one-component quick-curing chemically reactive adhesives. However, in the adhesion of rubber or leather among various adherends, the adhesion portion may be hardened due to the rigidity of the cyanoacrylate polymer, and the flexibility inherent in the base material may be lost. In addition, in the temporary fixing bonding work, for example, in order to impart gloss to the surface of the decorative component, when the component is temporarily bonded to the desk rotating body and polished, when the cyanoacrylate adhesive is removed, the bonding strength is too strong. It is difficult to use because it can make cutting work difficult.

Conventionally, as a countermeasure, a method of blending a plasticizer or an organic solvent has been proposed. For example, a method of blending a plasticizer and a carboxylic acid (JP-A-52-115836) or a method of blending a plasticizer with a PVC-VAC copolymer is proposed. Compounding method (Japanese Patent Application Laid-Open No. 60-1663)
61), Method of blending dioxane (JP-B-49-23811)
Alternatively, a method of blending trichlorotrifluoroethane (JP-A-57-96070) has been proposed.

[Problems to be solved by the invention]

The method of blending a general-purpose plasticizer with 2-cyanoacrylate is that the plasticizer is insoluble in 2-cyanoacrylate, or the stability of the adhesive is reduced due to the strong anionic activity of 2-cyanoacrylate, or There is a problem that the most characteristic instantaneous bonding function is remarkably reduced, or the cured polymer is tacked by bleeding of the plasticizer.

In addition, the method of blending an organic solvent often similarly deteriorates the stability and instantaneous adhesive function of 2-cyanoacrylate, and the organic solvent permeates through a polyethylene container during storage and volatilizes, resulting in an unbalanced composition. Problem.

(B) Configuration of the Invention [Means for Solving the Problems] The present inventors have conducted various studies to solve the above problems, and as a result, have found that a phthalate-based compound or a polycarbonate diol having a melting point of 20 ° C. or higher is obtained. It has been found that the intended purpose can be achieved by blending with 2-cyanoacrylate, and the present invention has been completed here.

That is, the present invention has a melting point of 2-cyanoacrylate.
The present invention relates to an adhesive composition comprising a phthalate compound or a polycarbonate diol at a temperature of 20 ° C. or higher.

The 2-cyanoacrylate used in the present invention is used as a main component of a cyanoacrylate-based adhesive known as an instant adhesive, and is represented by the general formula (1).

(1) General formula of 2-cyanoacrylate wherein R is an organic group such as an alkyl group, an alkoxyalkyl group, an aralkyl group, a cycloalkyl group, an alkenyl group, and an aryl group.

Specific compounds of 2-cyanoacrylate include:
Some examples include:

2-cyanomethyl acrylate, 2-cyanoethyl acrylate, 2-cyano n-propyl acrylate, 2
-Cyanoisopropyl acrylate, 2-cyano n-pentyl acrylate, 2-cyanomethoxymethyl acrylate, 2-cyanomethoxyethyl acrylate, 2-
Cyanoethoxymethyl acrylate, 2-cyanoethoxyethyl acrylate, 2-cyanopropoxyethyl acrylate, 2-cyanobutoxyethyl acrylate,
2-cyanotetrahydrofurfuryl acrylate, 2-
Cyano (2,2,2-trifluoroethoxy) ethyl acrylate, 2-cyanoallyl acrylate, 2-cyanocyclohexyl acrylate, and the like.

In the composition of the present invention, the following stabilizers, thickeners or modifiers generally used for cyanoacrylate-based adhesives can be blended and used as necessary.

Stabilizer: SO _2, aromatic sulfonic acid, BF ₃ - ether, HQ, M
EHQ thickener: polymethacrylate, cellulosic polymer,
Acrylic rubber Thixating agent: fumed silica, dehydrated castor oil Accelerator: polyethylene glycol, crown ether Functional modifier: polyvalent carboxylic acid, elastomer, etc.

On the other hand, in the present invention, the phthalate compound having a melting point of 20 ° C. or more as a compound used in combination with 2-cyanoacrylate or polycarbonate diol is as follows.

Phthalate compounds are widely used as plasticizers for synthetic resins, such as dioctyl phthalate (DOP) and dibutyl phthalate (DBP), and are also used as plasticizers in cyanoacrylate adhesives.
Those used in the present invention generally have a melting point not used as a plasticizer and have a melting point of 20 ° C. or higher. Specifically, dimethyl isophthalate (melting point 67 ° C.), dicyclohexyl phthalate (63.5 ° C.), ethyl Phthalylethyl glycolate (20 ° C), diphenylphthalate (65 ° C), bis (2,2,2-trifluoroethyl) phthalate (41 ° C)
And so on. Among these compounds, a preferred compound for the present invention is ethylphthalylethyl glycolate.

Polycarbonate diols can be produced by the reaction of glycol with phosgene or bis-chloroformate, the condensation of glycol with dialkyl carbonate, or the transesterification of glycol with alkylene carbonate, and mainly have the following structure.

HOR-O-CO-O _n While the R-OH present invention is the melting point of 20 ° C. or more polycarbonate diol is used, the average molecular weight in no alkylene group in the above structural formula R is a branched 4-8 carbon atoms But
Those having about 200 to 1300 are preferable, and an alkylene group having 6 carbon atoms is particularly preferable.

These compounds can be used alone or as a mixture of two or more.

The compounding ratio of the specific phthalate compound to 2-cyanoacrylate is 1 to 60 of the total amount of the two.
wt%, more preferably 5 to 45 wt%
Range. If the compounding ratio of the compound is less than this range, the intended flexibility of the cured polymer cannot be obtained, and if it exceeds this range, the adhesive function is unpreferably reduced.

(Operation)

By blending the specific phthalate compound or the like according to the present invention with 2-cyanoacrylate, lubricity between cured polymer molecules is improved, and flexibility is increased. In addition, since these specific phthalate-based compounds and the like are inactive with respect to 2-cyanoacrylate, they do not impair the stability of the adhesive composition and do not develop tack on the surface of the cured polymer. .

On the other hand, the effect of diluting 2-cyanoacrylate by blending the specific phthalate-based compound of the present invention also has the effect of appropriately reducing the adhesive strength without significantly impairing the original instant adhesive function.

[Examples and Comparative Examples]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

 The various test methods are as follows.

(1) Set time (based on JIS K 6861) Test piece (hard PVC or ABS, 12.7 × 12.7 × 38m
m), apply adhesive composition to one cross section, butch both sides (adhesive area = 1.61 cm ² ), apply finger pressure lightly, and leave to stand.
Measure the time to withstand 2.5 kgf.

Measurement conditions: 23 ° C, 60% RH (2) Tensile bond strength (based on JIS K 6861) The same test piece was bonded in the same manner as the set time measurement, and after standing at 23 ° C, 60% RH x 24 hours It is measured at a tensile speed of 50 mm / min using a Strograph W-type testing machine.

(3) Shore hardness The hardness is measured by the penetration into the adhesive composition polymer (10 × 10 × 10 mm) using a Shore hardness meter (type D).

(4) Surface tack The test piece after the measurement of the tensile adhesive strength is peeled off and the interface is observed by finger touch.

(5) Stability The adhesive composition was filled in a polyethylene container (20 ml), sealed, and heated at 70 ° C. for 5 days to observe the liquid property.

Example 1, Comparative Example 1 50 gr of each of the following three phthalate compounds was
-An adhesive composition prepared by dissolving in 50 gr of cyanoethyl acrylate was tested.

In addition, as Comparative Example 1, the same general plasticizer was dissolved in 50 gr of each of the following general plasticizers in 50 gr of 2-cyanoethyl acrylate, and an adhesive composition and 2-cyanomethyl acrylate alone were similarly tested.

Table 1 shows the test results of these adhesive compositions.

Example-2, Comparative Example-2 Polycarbonate diol (Toa Gosei Chemical Industry Co., Ltd.)
(Carbodiol D-1000, melting point 37 ° C.) 30 g of each was dissolved in 70 g of 2-cyanoacrylate shown below and tested for an adhesive composition.

In addition, as Comparative Example-2, a test was similarly performed on the 2-cyanoacrylate alone.

 Table 2 shows the results.

(C) Effects of the Invention The following effects can be expected by blending the specific phthalate compound or the like according to the present invention with 2-cyanoacrylate.

(1) Since the cured polymer is flexible, it is possible to bond rubber, leather, and fibers which are conventionally considered to be difficult to bond.

(2) Since there is no tack in the cured polymer, there is little thermal change, and there is no dirt around the bonded portion.

(3) Suitable for temporary bonding.

(4) Good storage stability of the adhesive composition.

The above properties can be set to desired values by changing the type and blending amount of a specific specific phthalate compound, and thus can be adjusted according to the purpose of use.

The composition prepared in this way further expands the application range of the conventional cyanoacrylate-based adhesive as a one-component quick-setting adhesive, and greatly contributes to various fields.

Claims (1)

(57) [Claims] 1. An adhesive composition comprising 2-cyanoacrylate and a phthalate compound or a polycarbonate diol having a melting point of 20 ° C. or higher.