JP2769232B2 - Acrylic adhesive composition - Google Patents

Description

The present invention relates to a two-part acrylic adhesive composition.

[Prior Art] The demand for acrylic adhesives that cure in a short time at room temperature tends to increase year by year from the viewpoint of labor saving, resource saving and energy saving. Conventionally, there are an instant adhesive, an anaerobic adhesive, a two-part acrylic adhesive, and the like, which are well known as a room-temperature fast-curing acrylic adhesive.

Although the instant adhesive has excellent workability, it generally has low peel strength and impact strength, and is inferior in heat resistance and moisture resistance.
The range of use is significantly limited.

Since the anaerobic adhesive is an adhesive that is cured by pressing the adhesive between the materials to be bonded and blocking the air, a portion that comes into contact with the air, such as a stick-out portion, is not cured. Therefore, even if the bleeding portion can be cured by light irradiation, if the clearance inside the porous adherend or between the adherends that cannot be irradiated with light is large, it does not sufficiently cure, resulting in poor adhesion.

Two-component acrylic adhesives, commonly referred to as second-generation acrylic adhesives (SGAs), are two-component, but do not require accurate metering of each component, and require extremely rough metering and mixing (sometimes two-component). It is widely used because it has excellent workability of curing at room temperature for several minutes to several tens of minutes at liquid temperature only, and also has high peel strength and impact strength, and good curing of the exposed part. It has become. However, labor saving,
From the viewpoint of resource saving and energy saving, there is an increasing demand for further shortening the curing time of such an acrylic adhesive at room temperature for several minutes to tens of minutes.

Adhesives that cure quickly have been developed to meet such demands. For example, the adhesive disclosed in U.S. Pat. No. 4,434,503 comprises a urethane acrylate, acrylate monomer, aromatic perester, organic acid, and transition metal, and cures with a set time of 45 seconds. The adhesive disclosed in JP-A-60-199085 comprises a specific urethane acrylate, a (meth) acrylate monomer, a peroxyester, and an accelerator comprising a compound forming a redox system with the peroxyester. Also, it is cured with a fast set time of less than one minute. Further, the adhesive composition disclosed in JP-A-55-65277 is a mixture of chlorosulfonated polyethylene and a specific acrylic monomer in a specific ratio, and comprises a cumene hydroperoxide, an aldehyde-amine condensate, and a transition metal. It is disclosed that it comprises an oxidizing organic compound and cures with a curing time of 5 to 10 seconds. However, although these adhesives all have quick-curing properties, when the adherend is made of aluminum, stainless steel, chromate plating, etc., it is difficult to say that the adhesiveness is sufficient, and the usable range is limited. .

It is also known to use an acidic phosphoric acid compound to improve the adhesion of an acrylic adhesive to aluminum, stainless steel, chromate plating, etc.
No. 147477, U.S. Pat. No. 4,731,146). However, it is known that an acidic phosphoric acid compound delays the curing rate when blended with an acrylic adhesive (U.S. Pat. No. 4,731,146). A photocurable two-pack type composition to be fixed is disclosed, and although an acidic phosphoric acid ester monomer is described as an acrylic compound that can be used, the performance of a composition using the monomer is not specified.

Saccharin is known to be used as a curing accelerator in anaerobic adhesives, and JP-A-51-132234 and JP-A-61-101579 disclose acidic phosphoric acid compounds in anaerobic adhesives. In some cases, the adhesive is used to improve the adhesion at the interface, but the anaerobic adhesive has the above-mentioned disadvantages.

JP-A-61-233073 discloses an example in which saccharin is used in a two-pack type acrylic adhesive using a monomer having a specific structure, and polymerizable phosphates are described as an adhesion improver. However, the performance of a composition containing saccharin and polymerizable phosphate esters is not shown.

[Problems to be Solved by the Invention] It is an object of the present invention to provide a two-pack type acrylic adhesive composition having fast curing and good metal adhesion.

[Means for Solving the Problem] As a result of intensive studies, the present inventor has found that an acrylic compound selected from (meth) acrylic acid and its ester and a composition containing a specific compound have excellent fast-curing properties as an adhesive. Have been found to have metal adhesion, and have completed the present invention.

That is, the present invention provides: a) an acrylic compound selected from (meth) acrylic acid and its ester; b) a polymerization initiator selected from peroxyester; c) a first solution containing saccharin; and d) a reaction condensation of an amine and an aldehyde. E) a second solution containing a copper salt, wherein at least the first solution has the following general formula (I) [Where R is an alkyl group, an alkoxyalkyl group or
CH ₂ = CR ₁ -CO (OR ₂ ) _m- (where R ₁ is H- or CH
₃ -, R ₂ is _{-C 2 H 4 -, - C} 3 H 6 -, −C ₄ H ₈ −, −C ₆ H ₁₂ − or And m is an integer of 1 to 10. ), And n is 1 or 2. ] It is an acrylic adhesive composition containing the acidic phosphoric acid compound shown by these.

The acrylic compound selected from the (a) component (meth) acrylic acid and its ester used in the first liquid of the acrylic adhesive composition of the present invention may be any as long as it is capable of radical polymerization. It is as follows.

A monomer represented by the general formula AOR ₃ (II).

Here, A is a (meth) acryloyl group, CH ₂ CHCHCOOCH
₂ —CH (OH) CH ₂ — or CH ₂ ＣC (CH ₃ ) COOCH ₂ —CH (O
H) CH ₂ —, wherein R ₃ is H— or an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, a benzyl group, a phenyl group, a tetrahydrofurfuryl group, a glycidyl group, a dicyclopentanyl group, a dicyclopentenyl Represents a (meth) acryloyl group.

Such monomers are specifically (meth) acrylic acid,
Methyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycerol (Meth) acrylate, glycerol di (meth) acrylate and the like.

Monomer represented by the general formula _{A-O-R 4 O p} R 3 (III).

In the formula, each of A and R ₃ represents A and R in the general formula (II).
Is the same as R _3. R ₄ is _{-C 2 H 4 -, - C} 3 H 6 -, _{-C 4 H 8 -, - C} 6 H 12 - represents, p is an integer of 1 to 25.

Specific examples of such a monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ethoxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, and phenoxyethyl (meth) acrylate. ) Acrylate, dicyclopentenyloxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,
6-hexanediol di (meth) acrylate and the like.

General formula A monomer represented by

In the formula, A is the same as A in the general formula (II), and R ₄ is the same as R _{4 in the} general formula (III). R ₅ represents H or an alkyl group having 1 to 4 carbon atoms, and q represents an integer of 0 to 8.

Specific examples of such a monomer include 2,2-bis (4-methacryloxyphenyl) propane and 2,2-bis (4-methacryloxyphenyl) propane.
Bis (4-methacryloxyethoxyphenyl) propane, 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 2,2-bis (4-methacryloxypropoxyphenyl) propane, 2,2-bis (4- (Methacryloxytetraethoxyphenyl) propane and the like.

(Meth) acrylic acid esters of polyhydric alcohols not included in the monomers described above and in the above.

Specific examples of such a monomer include trimethylolpropane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. No.

A urethane prepolymer having a (meth) acryloyloxy group.

Specifically, such a monomer is obtained by reacting a (meth) acrylate having a hydroxyl group with an organic polyisocyanate and a polyhydric alcohol. Here, specific examples of the (meth) acrylate having a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and (meth) acrylate.
Hydroxybutyl acrylate and the like can be mentioned. Also,
Specific examples of the organic polyisocyanate include toluene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Specific examples of the polyhydric alcohol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyester polyol, and the like.

The monomers described above, and, can be used alone or in combination of two or more, but it is preferable that at least one of the monomers constituting the component a is used.
It is desirable that the species be a urethane prepolymer having (meth) acryloyloxy groups as described above.

Specific examples of the polymerization initiator selected from the peroxyesters that are the component b used in the present invention include tertiary butyl peroxybenzoate, tertiary butyl peroxyacetate, tertiary butyl peroxyisobutyrate, and tertiary butyl peroxyester. Oxyphthalate and the like can be mentioned, and among them, tertiary butyl peroxybenzoate is most preferable.

The preferable mixing ratio of the components a and b contained in the first liquid is 0.1 to 10 parts by weight, particularly preferably 1 to 7 parts by weight, based on 100 parts by weight of the component a.

The saccharin used as the component c in the present invention contains o-sulfobenzoic imide, a salt thereof or both of them, and the amount of saccharin is expressed as o-sulfobenzoic imide.

The addition amount of the saccharin of the c component is 100 parts of the a component in the first liquid.
The amount is 0.05 to 2 parts by weight, preferably 0.1 to 2 parts by weight with respect to parts by weight. If the amount of saccharin is less than 0.05 part by weight, the effect of accelerating curing is small, and if it exceeds 2 parts by weight, a decrease in adhesive strength is observed.

A photopolymerization initiator can be further added to the first liquid. There is no particular limitation on the photopolymerization initiator used, and any commonly used photopolymerization initiator can be used.Examples include benzyl, benzophenone, benzoin ethyl ether, benzyldimethyl ketal, and derivatives thereof. It is also possible to use two or more kinds in combination.

The addition amount of the photopolymerization initiator is preferably 0.05 to 7 parts by weight, particularly preferably 0.5 to 5 parts by weight based on 100 parts by weight of the component a in the first liquid.

Next, the d component and the e component contained in the second liquid will be described.

The reaction condensate of the amine and the aldehyde of the d component used in the present invention is, for example, at least 1 mole per mole of the amine in the presence of a carboxylic acid such as acetic acid or propionic acid or an inorganic acid such as phosphoric acid or sulfuric acid. Mole, preferably 1.5
And those obtained by reacting ア ル デ ヒ ド 3 mol of aldehyde at 40-70 ° C. The amine used to obtain the condensate is ethylamine, propylamine,
Primary aliphatic amines such as butylamine; primary aromatic amines such as aniline and naphthylamine; and aldehydes such as formaldehyde, acetaldehyde,
Examples thereof include aliphatic aldehydes such as propionaldehyde and butyraldehyde.

The copper salt of the component e is an organic or unreasonable salt, and examples thereof include copper acetate, copper naphthenate, copper octenoate, an acetylacetone copper complex, and cupric chloride.

In order to obtain a second liquid containing the d component and the e component, a method of dissolving or diluting these in a volatile organic solvent and using the same can uniformly mix the d component and the e component. Also excellent in nature. Examples of the volatile organic solvent include, for example, methylene chloride, trichloroethane, acetone, methyl ethyl ketone, ethyl acetate, toluene,
Methanol, ethanol and the like can be mentioned, and volatile organic solvents can be used alone or in combination of two or more.

The concentration of the component d in the second liquid is 1% by weight or more, especially 10% by weight.
It is desirable that the content be not less than% by weight.

The amount of the component e is 10% in terms of copper equivalent concentration in the second liquid.
It is desirable that the concentration be from 1 to 10,000 ppm, especially from 50 to 1000 ppm.

The acrylic adhesive composition of the present invention is a two-pack type acrylic adhesive composition comprising a first liquid and a second liquid, and at least the first liquid has the following general formula (I) [Where R is an alkyl group, an alkoxyalkyl group or
CH ₂ = CR ₁ -CO (OR ₂ ) _m- (where R ₁ is H- or CH
₃ -, R ₂ is _{-C 2 H 4 -, - C} 3 H 6 -, −C ₄ H ₈ −, −C ₆ H ₁₂ − or And m is an integer of 1 to 10. ), And n is 1 or 2. ] The acidic phosphoric acid compound shown by these is contained. Specific examples of the compound include butyl acid phosphate and 2-butyl acid phosphate.
Examples include ethylhexyl acid phosphate, butoxyethyl acid phosphate, acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, and bis (2- (meth) acryloyloxyethyl) phosphate.
These acidic phosphoric acid compounds can be used alone or in combination of two or more.

The acidic phosphoric acid compound must necessarily be contained in the first solution. However, when it is contained in the first liquid, it may be contained in the second liquid.

When the amount of the acidic phosphoric acid compound is mixed only with the first liquid, it is preferably 0.05 to 10 parts by weight, particularly preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the component a in the first liquid. When the compound is mixed in both the first liquid and the second liquid, 0.05 to 10 parts by weight, particularly 0.5 to 7 parts by weight of the first liquid is added to 100 parts by weight of the component a in the first liquid. It is preferable that the concentration of the compound in the second liquid is 0.05 to 10
It is preferred that the compounding be performed so as to be 0.5% by weight, particularly 0.5 to 7% by weight.

Various additives can be contained in the adhesive composition of the present invention as needed. For adjusting the viscosity and the flow characteristics, a thickener or a thixotropic agent can be added. Examples of the thickener include various synthetic rubbers such as nitrile butadiene rubber and chlorosulfonated polyethylene, and various thermoplastic polymers such as metal methacrylate-butadiene-styrene copolymer (MBS) and linear polyurethane.

Examples of the thixotropic agent include finely divided silica, finely divided hydrophobic silica, and the like.

Further, the acrylic adhesive composition of the present invention can be photocured by adding a photopolymerization initiator to the first liquid and applying ultraviolet light to the protruding portion as described above, Paraffin or the like can be added to cure the protruding portion.

Further, various polymerization inhibitors for the purpose of improving storage stability,
It is also possible to add known additives such as antioxidants. Further, depending on the purpose, a plasticizer, a filler, a coloring agent, and the like can be added.

The acrylic adhesive composition of the present invention cures quickly and in a short time by contacting the first liquid and the second liquid.

When using the acrylic adhesive composition of the present invention, since the curing speed is high, the first liquid is applied to one adherend, the second liquid is applied to the other adherend, and the second liquid is applied. When a volatile solvent is contained, it is preferable to volatilize the volatile solvent and then bond the applied surfaces of the adherends together. When a protruding portion or the like where the first liquid and the second liquid are not contacted by this method occurs, a photopolymerization initiator can be added to the first liquid, and the protruding portion can be cured by irradiating ultraviolet rays.

Examples Hereinafter, the acrylic adhesive composition of the present invention will be further described with reference to examples.

Examples 1-2 and Comparative Examples 1-2 a component, b component, c component and various acidic phosphoric acid compounds were mixed in the proportions shown in Table 1, and MBS was added for further thickening. did.

On the other hand, Noxeller 8 (trade name: Ouchi Shinko Chemical Co., Ltd .; n-butyl aldehyde aniline) as the d component, e
As a component, copper naphthenate (copper concentration 5%) and a solvent were mixed at the ratio shown in Table 1 to obtain a second liquid.

The fixing time of the adhesive compositions of Examples and Comparative Examples was measured by the following method, and the results are shown in Table 1.

Measurement of fixation time One of two iron test pieces for shear strength measurement (ss-41, sanding treatment, 100 × 25 × 1.6 mm) was coated with the first liquid, and the second liquid was coated with the other liquid. Apply to one side of one test piece,
After the volatile solvent of the second liquid was volatilized, the application surfaces of the adherends were adhered together and adhered, and the time required for removal even when a load of 4 kg was applied was defined as the fixing time.

Example 3 and Comparative Example 3 a component, b component, c component, acidic phosphorus compound and MBS
Was mixed in the proportions shown in Table 2 to obtain a first liquid. Also, d
The component, the e component, and the solvent were mixed at the ratio shown in Table 2 to obtain a second liquid. The properties of the adhesive compositions of Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2.

Tensile shear strength A 2 mm thick aluminum test piece (A-5052, sanding treatment) as an adherend was adhered according to ASTM D-1002, and an Instron 1123 type tensile tester (tensile speed 10 mm) was used.
/ Min).

T-type peel strength A 0.3mm thick iron test piece (SPCC, sanding treatment) is adhered as an adherend according to ASTM D-1876, and is Instron.
It was measured with a 1123 type tensile tester (tensile speed: 50 mm / min).

Impact Strength An iron adherend (sanding treatment, 44 × 25 × 19 mm and 25 × 25 × 9 mm) was adhered according to ASTM D-950, and measured using an Izod impact tester.

Example 4 and Comparative Example 4 To 100 parts by weight of the first liquid obtained in Example 1, 1 part by weight of benzyldimethyl ketal as a photopolymerization initiator was added and dissolved to prepare a first liquid. The second liquid obtained in Example 1 was applied to one surface of one of the two iron test pieces for tensile shear strength measurement so as not to protrude, and the above photopolymerization was applied to one surface of another test piece. The first liquid to which the initiator was added was applied, and the coated surfaces of the test pieces were matched with each other, and the test pieces were adhered so that the first liquid protruded.
This protruding part is covered with ultraviolet rays (TOSQUA, manufactured by Toshiba Corporation).
When irradiated with 400, lamp output of 80 W / cm, irradiation distance of 15 cm) for 10 seconds, the protruding part was cured, and the tack of the cured product was completely eliminated by touching the surface with a finger.

In the sample obtained by the same method as described above, when the protruding portion was not irradiated with ultraviolet rays, the protruding portion remained tacky on the surface after one day or was in an uncured state.

[Effect of the Invention] The adhesive composition of the present invention has an extremely fast curing reaction at room temperature and has excellent adhesiveness to a wide range of adherends including metals and chromate-treated surfaces, so that the production line can be shortened and streamlined. And the industrial benefits are extremely large.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C09J 4 / 02,4 / 06,161 / 20

Claims (2)

(57) [Claims] 1. A) an acrylic compound selected from (meth) acrylic acid and its ester; b) a polymerization initiator selected from peroxyester; c) a first solution containing saccharin; and d) a reaction between an amine and an aldehyde. E) a second liquid containing a condensate e) copper salt, wherein at least the first liquid contains the following general formula (I) [Where R is an alkyl group, an alkoxyalkyl group or
CH ₂ = CR ₁ -CO (OR ₂ ) _m- (where R ₁ is H- or CH
₃ -, R ₂ is _{-C 2 H 4 -, - C} 3 H 6 -, −C ₄ H ₈ −, −C ₆ H ₁₂ − or And m is an integer of 1 to 10. ), And n is 1 or 2. ] The acrylic adhesive composition characterized by containing the acidic phosphoric acid compound shown by these. 2. The acrylic adhesive composition according to claim 1, wherein the first liquid contains a photopolymerization initiator.