JPS61136567A - Bonding - Google Patents

Abstract

PURPOSE:To bond inert adherends readily at a low cost, by pretreating the adherends with a titanate coupling agent and performing bonding with an alpha- cyanoacrylate adhesive. CONSTITUTION:A cyano adhesive is prepared by adding anionic polymerization inhibitor, thickener, etc. to an alpha-cyanoacrylate of the formula (where R is 1-16C alkyl, alkenyl, cyclohexyl, phenyl, haloalkyl, alkoxyalkyl, tetrahydrofurfuryl, etc.). A 100-100,000ppm solvent soln. of at least one titanate coupling agent and amine, when necessary, is applied to materials which are difficult to bond, such as polyethylene or polypropylene, and the coated materials are joined together by use of the above adhesive, followed by clamping for aging.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an adhesion method using α-cyanoacrylate, and more specifically, to adhesive bonding of polypropylene, polyethylene, EPDM, etc. using an α-cyanoacrylate adhesive. Concerning methods of gluing materials.

(b) Conventional technology general formula (1) % formula % (where R is an alkyl group having 1 to 16 carbon atoms, an alkenyl group, a cyclohexyl group, a phenyl group, a halogenated alkyl group, an alkoxyalkyl group, a tetrahydrofurfuryl group) α-Cyanoacrylic acid ester (hereinafter abbreviated as α-cyanoacrylate), represented by It polymerizes quickly at room temperature to form a strong polymer.

Utilizing this property, adhesives based on this seven-terminal, that is, α-cyanoacrylate adhesives (hereinafter abbreviated as cyano adhesives), are used as instant adhesives for electrical equipment, transportation equipment, etc. Precision mechanical equipment.

It is widely used in various industrial industries such as machinery, and in the general household to bond rubber, plastics, ceramics, etc., and is also applied in the medical field such as dental treatment and surgery.

However, although cyano adhesives have the above-mentioned characteristics, depending on the material of the adherend, they have poor weather resistance, water resistance, and impact resistance, and some have extremely poor adhesive properties themselves. In particular, polyethylene, polypropylene, EPDM, etc. have low polarity and are difficult to bond by normal methods even with cyano adhesives, and these are called adhesive materials.

Conventionally, the method of bonding difficult-to-bond materials such as polyethylene, polypropylene, and EPDM with cyano-based adhesives is to treat the surface of the adherend in advance with an adhesive substance such as rubber or acrylic adhesive as a primer, and then apply cyano-based adhesives. The method of applying adhesives and the surface of the adherend are treated in advance chemically, thermally, electrically, or by ultraviolet rays, radiation, corona discharge, plasma, etc.

Efforts have been made to increase adhesiveness by increasing the adhesion area, adding polar groups through oxidation, etc.

(c) Problems to be solved by the invention When bonding difficult-to-bond materials using cyano-based adhesives, the various pretreatments described above do not necessarily meet sufficient requirements for bonding work. However, those using an adhesive as a primer have insufficient performance in terms of both adhesion and adhesive strength. In addition, although surface treatment method 1 improves adhesive strength, chemical treatment requires a treatment agent such as a strong acid, requires a long treatment time, and has safety and waste liquid problems. Furthermore, heat treatment, electric treatment, and ultraviolet treatment require an energy source and are therefore expensive, and large-scale equipment is required for mass production. The equipment for radiation treatment, corona treatment, and plasma treatment is expensive, and their use requires specialized technicians.

The present invention uses a cyano adhesive to bond difficult-to-bond materials such as polyethylene and polypropylene-EPDM.
This was achieved through intensive research with the aim of eliminating the drawbacks of the conventional technology as described above.

(d) Means for Solving the Problems The bonding method of the present invention is characterized in that the surface of the adherend is pretreated with a titanate coupling agent when bonding using an α-cyanoacrylate adhesive.

The α-cyanoacrylate used in the present invention has the general formula (
1), specifically, for example, methyl-α-cyanoacrylate, ethyl-α-cyanoacrylate, propyl-α-cyanoacrylate, butyl-α-cyanoacrylate, amyl-α-cyanoacrylate, allyl-α -cyanoacrylate, methoxyethyl-α-cyanoacrylate, ethoxyethyl-α-cyanoacrylate, tetrahydrofurfuryl-α-cyanoacrylate, and the like.

The cyano adhesive used in the present invention is a conventionally known cyano adhesive, but specifically, the above-mentioned α-cyanoacrylate is combined with other anionic polymerization inhibitors such as SO2, hydroquinone, hydroquinone, etc. Common radical polymerization inhibitors such as monomethyl ether, 2,6-di-t-phthyl-P-cresol, thickeners, plasticizers, colorants, surfactants.

It can contain strength improvers, solvents, etc.

The titanate coupling agent used in the present invention includes organic titanium compounds such as tetra-1-propoxytitanium, tetra-n-butoxytitanium, tetrakis(2-ethylhexoxy)titanium, tetrastearoxytitanium, di-mi- Propoxy bis(acetylacetonato) titanium, di-n-butoxy bis(triethanolaminato) titanium, dihydroxy bis(lactato)
Titanium, titanium-1-propoxyoctylene glycolate, i-propoxytitanium trimy stearate, (ethylene glycolade) titanium bis(dioctyl phosphate), tri-n-butoxytitanium monostearate, i-propoxytitanium dimethacrylate-1- Stearate, i-propoxytitanium tris(4-aminobenzoate), i-propoxytitanium tris(dioctyl phosphate), isopropyltriisostearoyl titanate, isopropyltri(N-aminoethyl aminoethyl)titanate, isopropyltris(dioctylpyrophosphate) ) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditolyldecyl phosphite) titanate, tetra(2゜2-diallyloxymethyl-1-butyl) bis(didodecyl) phosphite titanate, bis(dioctyl) (pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, etc., and others of the general formula (n) (wherein, R: lower alkyl group such as methyl, ethyl, propyl, butyl, n = 1 -20) are mentioned, and two or more of these can also be used in combination.

When using a titanate coupling agent as a pretreatment, it can be dissolved in a solvent 1 that is compatible with the titanate coupling agent, such as lower alcohols, esters and ketones of lower fatty acids, hydrocarbons, and halogenated hydrocarbons. Preferred examples include, specifically, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and methylene chloride.

1, L, 1-trichloroethane, dichloroethane, trichlortrichloroethane, perchloroethane, n-hexane, benzene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, 1-propyl acetate, n-propyl acetate, acetic acid
Examples include n-butyl, isobutyl acetate, benzyl acetate, and cyclohexyl acetate. Among these solvents, when alcohols are used, the adhesive strength is relatively low and may be unbalanced, making it difficult to use.

On the other hand, when halogenated hydrocarbons are used, the adhesive strength is greater than when other solvents are used, and moreover, the effect is more stable.

The amount of titanate coupling agent added to the solvent is 10
0 to 100,000 ppm, preferably l,
000 to 50,000 ppm. 100ppm
If it is less than 100,000 pp++, sufficient adhesive strength will not be exhibited when bonded with α-cyanoacrylate, and if it is more than 100,000 pp++, cohesive failure will occur in the titanate coupling agent layer.

The adhesion method of the present invention can be similar to the method used for conventional cyano adhesives using primers.

For example, a titanate coupling agent solution is applied to one (or both) of the two adhesive surfaces of an adherend that has been previously cleaned using a conventional method, and after the solvent has evaporated, or at an appropriate time, a cyano-coupling agent solution is applied to one of the adhesive surfaces. After applying the adhesive and volatilizing the solvent, or at an appropriate time, apply a cyano-based adhesive to one of the adhesive surfaces, bond them together, press them, and cure them.

In addition, when α-cyanoacrylate is applied and bonded to the part pretreated with these titanate coupling agents,
Curing speed may be slow. In such cases, the curing speed can be restored by adding amines to the titanate coupling agent in advance and using them together. Examples of amines used in this case include monoethanolamine, jetanolamine, triethanolamine, N,N-dimethyl-m-toluidine, and N.

N-dimethyl-p-toluidine, N,N-dimethyl-o
-Toluidine, dimethylaniline, diethylaniline,
Examples include quaternary ammonium salts.

(e) Effects According to the adhesive method of the present invention, adherends such as polyethylene, polypropylene, and EPDM, which are almost inert to α-cyanoacrylate, can be bonded using a conventional primer-treated cyano adhesive. Similarly, it has become possible to bond easily using inexpensive materials and simple work without losing the effectiveness and performance of cyano adhesives.

(f) Examples The effects of the adhesive method of the present invention will be explained below using examples and comparative examples.

Examples 1-7. Comparative Examples 1 to 3 1.1.1-Trichloroethane with the amount of di-n shown in Table 1
-Butoxy-bis(triethanolaminato) titanate was added and dissolved by shaking to prepare a primer. After applying a primer to the surface of a polypropylene board (25 x 100 x 21 m) and leaving it at a temperature of 20'C for 2 minutes,
One drop of cyano-based adhesive was added and bonded with a 172-inch overlap. After curing for 24 hours, the tensile shear strength was measured. The results are shown in Table 1.

The cyano adhesives used were Cyanobond W-300 (manufactured by Sumima Kagaku Kogyo Co., Ltd., ethyl-α-cyanoacrylate medium viscosity type) and Cyanobond RP (manufactured by Sumima Kagaku Kogyo Co., Ltd., ethyl-α-cyanoacrylate low viscosity type). type) and Cyanobond pon (manufactured by Sumima Kagaku Kogyo Co., Ltd., isopropyl-α-cyanoacrylate medium viscosity type).

The results in Table 1 show that by pre-treating with a titanate coupling agent, polypropylene, which is difficult to bond with ordinary cyano adhesives, can be bonded without losing the performance of the cyano adhesive.

Examples 8 to 15 Primers were prepared by adding and dissolving 20,000 ppm of various titanate coupling agents shown in Table 2 in various solvents. Examples 12B and 14B further added jetanolamine s, ooo PPC Example 15 to the above primer.
For B, 5,000 ppm of triethanolamine was added.Next, a primer was applied to a polypropylene plate in the same manner as in Example 1, and Cyanobond W-3 was added.
Adhesion and tensile shear strength were measured using 00 (described above).

The results are shown in Table 2.

The results in Table 2 show that polypropylene can be bonded by pretreatment with various titanate coupling agents.

Also, depending on the type of titanate coupling agent and the type of solvent, the development of adhesive strength may be delayed, but this can be overcome by adding amines to the primer in advance.

A solution consisting of di-n-butoxy-bis(triethanolaminato) titanate and 1.1.1-trichloroethane is the most effective primer.

When methyl alcohol is used instead of 1.1.1-trichloroethane, practical strength is obtained, but it is relatively weak, and the value is often unbalanced.

Examples 16 to 23 Primers were prepared by adding and dissolving 10,000 ppm of various titanate coupling agents shown in Table 3 in various solvents. In Example 21B, 5,000 ppm of N,N dimethyl-m-toluidine was added to the primer, in Example 22B, jetanolamine was added, and in Example 23B, triethanolamine was added at 5,000 ppm.

Next, in the same manner as in Example 1, primers were applied to the various adherends shown in Table 3, and then adhesion and tensile shear strength were measured using the cyano adhesives shown in Table 3. The results are shown in Table 3.

Claims (1)

[Claims] An adhesion method characterized in that, when adhering using an α-cyanoacrylate adhesive, an adherend is pretreated with a titanate coupling agent.