JPH02160881A - Adhesive composition - Google Patents

Abstract

PURPOSE:To make a compsn. anaerobic and curable at ordinary temp. and to improve the rate of adhesion to various materials and potlife at higher temp. and humidity by compounding a (meth)acryloylated monomer with an org. peroxide and a chlorophyll (or metal-substd. derivative thereof). CONSTITUTION:100 pts.wt. (meth)acryloylated monomer (a) {e.g. 2,2-bis(4- methacryloxydiethoxyphenyl)propane}, if necessary, emulsified in water with a water-soluble polymer and/or a water-dispersible polymer both having film forming property 0.2-10 pts.wt. org. peroxide (b) (e.g. cumene hydroperoxide), if necessary, encapsulated and 0.01-5 pts.wt. chlorophyll (c) (or metal substd. derivative thereof) (e.g. sodium copper chlorophyll) adsorbed on PVA with a degree of saponification of 70-99mol%, if necessary, dissolved or dispersed in an aq. medium or a nylon polymer water-soluble or soluble in a mixed solvent of water and an alcohol, are compounded.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention relates to an adhesive that has anaerobic curing properties, and in particular has a high adhesion speed to a wide variety of materials and can cure at room temperature. The present invention relates to an anaerobic adhesive that is moldable and has a long pot life even under conditions of high temperature and high humidity.

In this adhesive composition, for example, a one-component composition in which an organic peroxide is encapsulated in a capsule is used by precoating it on a metal material in advance to form a coating film of the adhesive composition. It is suitable for various fields, for example, as an adhesive for locking screws.

[Conventional technology]

Conventionally, one-component room-temperature curing adhesives that cure rapidly have mainly been made from monomers having an acryloyl group and/or methacryloyl group (hereinafter referred to as "(meth)acrylate monomers"). Anaerobically curable compositions have been used.

[Problem to be solved by the invention]

Conventional anaerobic curable compositions are compositions that remain oily when in contact with air or oxygen under low temperature, low humidity conditions, and rapidly harden when cut off from air or oxygen.

However, if stored under high temperature and high humidity conditions, it has the disadvantage that its adhesive ability is significantly reduced, and it has been particularly limited in applications where it is used as a so-called pre-coat, which is applied to metal surfaces in advance.

(B) Structure of the Invention [Means for Solving the Problems] The present invention provides polymerization of 0.2 to 10 parts of organic peroxide and chlorophyll or This is an adhesive composition containing metal-substituted chlorophyll (hereinafter collectively referred to as "chlorophylls").

[(meth)acrylate monomer]

The (meth)acrylate monomer of the present invention can be used as it is if it is physically homogeneously mixed with the other components constituting the present invention, but if it is emulsified in water using the method described above, it may cause chemical injuries. This is preferable because it can reduce risks and greatly improve coating properties.

That is, it has surface activity and a number average molecular weight of 3000 to 5.
The (meth)acrylate monomer can be emulsified by gradually adding it to an aqueous solution of about 0,000 polymer under vigorous stirring.

At this time, a water-soluble polymer and/or water-dispersible polymer having film-forming ability is added at the same time as the (meth)acrylate monomer is emulsified, or after the (meth)acrylate monomer has been emulsified in advance. When added, the resulting adhesive composition forms a resin film on the surface after application, making it possible to obtain a dry-touch coated surface, and chlorophylls are adsorbed to these film-forming polymers. This is preferable because the pot life of the adhesive composition, which is one of the objects of the present invention, can be improved more effectively.

Further, it is also possible to use a polymer that has a film-forming ability and can emulsify a (meth)acrylate monomer as described below.

The (meth)acrylate monomers used in the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, allyl (meth)acrylate.

Dimethylaminoethyl (meth)acrylate Glycidyl (meth)acrylate Methoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate Sulfopropyl (meth)acrylate, 2-hydroxyethyl acryloyl phosphite acetoxyethyl (meth)acrylate and methyl carpi Mono (meth)acrylates such as tall (meth)acrylate; ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate 1.3-butanediol di(meth)acrylate, polybasic acids and polyols and (meth)acrylates; A condensate consisting of polyester di(meth)acrylate obtained by dehydration condensation of acrylic acid and polyesterification reaction, epoxidized bisphenol A di(meth)acrylate, ethylene glycol, diethylene glycol or triethylene glycol, and epoxidized bisphenol (meth) Di(meth) obtained from acrylic acid
Di(meth)acrylates such as polyurethane di(meth)acrylates obtained from acrylates, diisocyanates, glycols and hydroxyalkyl(meth)acrylates; ) Compounds containing two or more acrylate structures.

Among these (meth)acrylate monomers, di(meth)acrylate of ethylene glycol, triethylene glycol or tetraethylene glycol: a condensate consisting of ethylene glycol, diethylene glycol or triethylene glycol and epoxidized bisphenol A; Di(meth)acrylate obtained from acrylic acid is preferable because it has a high adhesive strength when used as an adhesive composition.

Next, examples of polymers that have film-forming ability and can emulsify (meth)acrylate monomers in water include acrylic ester resins having a copolymer composition of 20 to 50% by weight of (meth)acrylic acid; Or methyl vinyl ether copolymer,
Polyvinylpyrrolidone, polyvinyl alcohol with a saponification degree of 70 to 99 mol%, ethylcellulose, hydroxypropylcellulose, methoxyhydroxypropylcellulose, ethylene-maleic anhydride copolymer, water-soluble or soluble in a mixed solvent of water and alcohol water-soluble polymers such as nylon polymers, urea resins, melamine fats, or block copolymers of polyethylene oxide and polypropylene oxide; acrylic acid ester resin emulsions, urethane emulsions, chloroprene polymer emulsions, or butadiene-acrylonitrile emulsions Water-dispersible polymers such as

Among these polymers, polyvinyl alcohol with a degree of saponification of 70 to 99 mol%, nylon polymer that is water-soluble or soluble in a mixed solvent of water and alcohol, or a mixture thereof has the ability to adsorb chlorophylls. It is very preferable, and is also preferable because it has the effect of suppressing the redox reaction in the adhesive composition.

Furthermore, among these polymers, it is more preferable to use a mixture of a polymer having a high emulsifying power of the (meth)acrylate monomer and a polymer having a high film-forming ability.

[Organic peroxide]

Powdered or liquid organic peroxide can be used as it is if it is physically uniformly mixed with the other components constituting the present invention, but by encapsulating it, the pot life is improved and it is possible to use a one-component type. A composition that is even more excellent as an adhesive composition can be obtained.

The encapsulation method involves dispersing a finely powdered organic peroxide in a urea-formalin prepolymer obtained by a methylenation reaction at a pH of 7.5 to 9, and then adjusting the pH to 2 to 3.
The method of encapsulating the polymer while lowering the temperature to 35 to 45°C and depositing the produced polymer in peroxide powder through methylenation reaction has excellent water resistance and oil resistance of the produced capsules. preferable.

As the organic peroxide used in the present invention, hydroperoxide, ketone peroxide, dialkyl peroxide, peroxy ester, diacyl peroxide, etc. can be used, but benzoyl peroxide or meta-toluoyl peroxide is particularly suitable. When organic peroxides with strong redox reactivity such as .

The amount of organic peroxide used is (meth)acrylate monomer 1
0.2 to 10 parts by weight are required, preferably 0.5 to 2 parts by weight.

If the amount is less than 0.2 parts by weight, the adhesive ability will not be sufficiently exhibited, while if it exceeds 10 parts by weight, more than the appropriate amount may be mixed in as foreign matter and the adhesive ability may deteriorate.

In addition, as described below, when a reducing agent that forms a redox system with an organic peroxide (hereinafter referred to as "reducing agent") is added to the adhesive composition, the amount of organic peroxide used is The amount may be small, and the preferred amount is 0.2 to 5 parts by weight.

[Chlorophylls]

In the present invention, it is necessary to coexist chlorophylls in a composition consisting of a (meth)acrylate monomer and an organic peroxide.

A known example that contrasts with the addition of chlorophylls in terms of technical philosophy is an anaerobic method in which a chelating agent that does not contain a =C=N group is added to a mixture of an acrylic acid ester monomer and a peroxide. Composition (Special Publication No. 51-20555)
can be mentioned.

For the above chelating agent, the chlorophylls of the present invention can be used, for example, as shown in the formula on the next page.
It has pyrrole nuclei, obviously =C=N
- group, and is essentially different from the above-mentioned known examples.

Furthermore, the chelating agent used in Japanese Patent Publication No. 51-20555 is intended to increase the stability of anaerobic compositions, which is the purpose of the present invention, that is, to increase the stability of compositions under high temperature and high humidity conditions before use. The mechanism is also different from that of reducing the redox reactivity of a product and preventing it from losing its desired good curing properties during use.

Chlorophylls can be used as they are in the composition of the present invention if they are physically uniformly mixed, but if the degree of saponification is 7.
It is added to an aqueous medium in which 0 to 99 mol% polyvinyl alcohol, a water-soluble or water-alcohol mixed solvent-soluble nylon polymer, or a mixture thereof is dissolved or dispersed, and adsorbed to these polymers. Particularly preferred is the method of using

Specific examples of chlorophylls include chlorophyll and metal-substituted chlorophylls in which magnesium is substituted with copper or zinc in the above formula showing chlorophyll, such as copper chlorophyll and zinc chlorophyll, and chlorophylls similarly substituted with sodium. Mixtures with the metal substitutes, such as sodium copper chlorophyll and sodium zinc chlorophyll, may be mentioned, but among these, sodium copper chlorophyll is preferred because of its high stability.

Regarding the amount of chlorophylls used, the effect can be seen if a small amount is present in the composition consisting of (meth)acrylate monomer and organic peroxide, but (meth)acrylate monomer 1
The amount is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 2 parts by weight.

If it is less than 0.01 part by weight, the effect of improving pot life will be small, and if it exceeds 5 parts by weight, the effect will not increase.

[Other substances that may be incorporated into the adhesive composition of the present invention] A reducing agent may be incorporated into the adhesive composition of the present invention for the purpose of further increasing the adhesion speed.

The compound can be used dissolved or uniformly dispersed in (meth)acrylate monomer, but (meth)
When emulsifying the acrylate monomer and using it, it is preferable to add it at the time of emulsification and uniformly disperse it.

Specific examples of such compounds include organic acid salts such as copper, cobalt, or manganese for organic hydroperoxides or peroxyesters; ethylenethiourea, tetramethylthiourea; , 2-mercaptobenzimidazole, and other hydrophobic mercapto compounds; hydrazine, 2-hydroxyhydrazine, benzoylhydrazine, and other hydrazine derivatives; sodium p-toluenesulfinate, L-ascorbic acid, triethylenediamine, and the like.

Among these, it is preferable to use ethylene thiourea or L-ascorbic acid because the reactivity increases.

For diacyl peroxides, dimethylaniline, dimethyl-p-)luidine, diethyl-p-)luidine, N,N dimethyl-p-anisidine, 0-sulfobenzoic acid imide; also mercaptoethanol, thiomalic acid, thioglycol. Water-soluble mercapto compounds such as acid, thiolactic acid, α-thiobutyric acid, mercaptoethylamine, or 0- or m-thiosalicylic acid are used, respectively.

Among these, it is preferable to use dimethyl-p-)luidine or 0-sulfobenzoic acid imide because the reactivity increases.

The amount of the compound used is (meth)acrylate monomer 10
The amount is preferably 0.1 to 5 parts by weight, more preferably 0.3 to 2 parts by weight.

When the amount is less than 0.1 parts by weight, the redox reactivity is weak, while when it exceeds 5 parts by weight, the balance of the redox reaction mechanism is lost and the pot life of the adhesive performance tends to be reduced.

Talc, which is commonly used to improve the properties of adhesive compositions, for example to impart thixotropic properties,
Silica, alumina or calcium carbonate, hydroquinone, methylhydroquinone, 2,4-dinitroanisole or 2,6- to maintain long pot life.
Ditertiary-butyl p-cresol and the like can be added.

[Function] The adhesive composition of the present invention has excellent anaerobic adhesive performance and pot life even without using a reducing agent.

The reason for this is not clear, but it is thought to be due to the unique chelating effect of chlorophylls on metal ions.

[Examples and Comparative Examples] The present invention will be explained in more detail by giving Examples and Comparative Examples below.

The performance of the adhesive composition of the present invention was evaluated using the following test method.

■ Evaluation in Examples 1 to 5 and Comparative Examples 1 to 2 (a) Application of adhesive composition to bolts and screws, adhesion test and initial adhesion test 8 Open diameter, length 401 yellow chromate and stainless steel (
Adhesive composition 0 is applied to the groove of the screw made of SUS304).
．． After applying 2g evenly, immediately tighten the nut with a torque of 230kg/cm, and test the starting return torque after leaving it at 23°C for 20 minutes (initial adhesion test) and the starting return torque after leaving it for 1 hour (adhesion test). sex test) was measured.

(b) Adhesive Performance Pot Life Test After 500 g of the adhesive composition was left uncovered in a glass beaker at 50°C and humidified at 95% relative humidity for 2 days, it weighed 230 kg/cm. The nut was tightened to a torque of 1, and the starting return torque was measured after being left at 23°C for 1 hour.

(C) Heat resistance test Tighten the nut to the coated screw in (a) with a torque of 230 kg/cm, continue heating at 150°C for 30 minutes, and return to startup while maintaining the temperature at 150°C. Torque was measured.

■Evaluation in Examples 6 to 8 and Comparative Example 3 (Application of adhesive composition to bolts and screws) Water-based adhesive was applied to the grooves of screws made of yellow chromate and stainless steel (SUS304) with a diameter of 8 mm and a length of 401 mm. 0.2 g of the agent composition was uniformly applied and then dried at 80° C. for 20 minutes to obtain an adhesive fastening type screw with a tack-free film formed on the surface.

(Adhesive performance and other evaluation tests) (a) Adhesiveness test and initial adhesion test A nut was tightened to the above-mentioned coated screw with a torque of 230 kg force/cm, and the start-up return torque was left at 23°C for 20 minutes. (Initial adhesion test) and starting return torque after standing for 1 hour (adhesion test) were measured.

(b) Adhesive performance pot life test After leaving the above-coated screw in a humidifier at 50°C and 95% relative humidity for 5 days, tighten the nut with a torque of 230 kg/cm, and leave it at 23°C. The starting return torque was measured after being left for 1 hour.

(C) Heat resistance test Tighten the nut to the coated screw of (a) with a torque of 230 kg/cm, continue heating at 150'C for 30 minutes, and return to startup while maintaining the temperature at 150°C. Torque was measured.

Example I 1000 g of NK BPE-200 (2,2 bis[4-(methacryloxyjethoxy)phenyl]propane, manufactured by Shin Nakamura Chemical Industry ■), 10 g of cumene hydroperoxide, and 10 g of sodium copper chlorophyll were mixed into 2
Pour into 2 beakers and mix at 1100 orp with a lab mixer.
The adhesive composition was obtained by stirring for 5 minutes.

Table 1 shows the results obtained for the composition according to the evaluation method described above.

Example 2, Comparative Example 1 The types and amounts of the (meth)acrylate monomer, organic peroxide, chlorophylls, or reducing agent in Example 1 were changed as shown in Table 1, and the other conditions were as in Example 1. Table 1 shows the test results for adhesive and acid compounds obtained in exactly the same manner as in Example 1.

Examples 3 to 5, Comparative Example 2 The types and amounts of the (meth)acrylate monomer, organic peroxide, chlorophylls, or reducing agent in Example 1 were changed as shown in Table 1, and the stirring speed was changed. Table 1 shows the test results of the adhesive composition obtained by using 2QOOrpm and performing the other conditions in exactly the same manner as in Example 1.

Example 6 (Preparation of (meth)acrylate monomer emulsion) In a 2i beaker, 860 g of pure water, Gohsenol GM-14 (partially saponified polyvinyl alcohol with a degree of saponification of 86 mol% and an average degree of polymerization of 1400, Nippon Gosei Kagaku Kogyo) (manufactured by 1) was added to make an aqueous solution. Afterwards, use a propeller type stirring device for 65 minutes.
Under orpm stirring, 1000 g of tetrahydrofurfuryl methacrylate and AQ-nylon A-70 (
66.7 g of a methanol solution containing 30 polymers of dimethylamino-substituted nylon (manufactured by Toshi ■) was charged, and 2
After stirring for a period of time, an aqueous emulsion was obtained.

This emulsion had emulsified particles with a particle size of 2 to 6 μm, and had a viscosity of 6000 cps at 6 rpm using a B-type viscometer.

(Encapsulation of organic peroxide) 31 Into a flask, add 1 aqueous formalin solution with a concentration of 37% by weight.
050 g, urea 393 g and triethanolamine 5
．． 1 g was charged, stirred at 70°C for 2 hours at 300 rpm using a propeller-type stirrer, and reacted to adjust the pH.
The viscosity at 5Qrpm measured by 8.1 and B-type viscometer is 7.5.
A prepolymer of cps was obtained.

Next, 1827 g of the above prepolymer aqueous solution was placed in container 51.
and 1827 g of pure water, adjusted the pH to 2.3 with IN sulfuric acid, added 38.4 g of benzoyl peroxide, heated to 40°C, and heated to 400 rpm with a homogenizer.
After reacting for 6 hours under stirring, the reaction was continued for 14 hours under stirring at 300 rpm using a propeller type stirring device.

The resulting slurry was neutralized with an IN aqueous solution of caustic soda,
After washing with pure water and methanol and drying on a tray at 40°C, 153.6 g of capsules containing 25% by weight of benzoyl peroxide and having a particle size of 20 to 50 μm with a urea resin coating were obtained. .

(Preparation of adhesive composition) The total amount of the (meth)acrylate monomer emulsion obtained above (containing 1000 g as (meth)acrylate monomer), 40 g of encapsulated organic peroxide (benzoyl peroxide) (containing 10g of chlorophyll) and 10g of chlorophyll were put into a 22 beaker and mixed with a homogenizer.
Stirring was performed at 1000 rpm for 5 minutes to obtain an aqueous adhesive composition.

Table 1 shows the results obtained for the liquid according to the evaluation method described above.

Example 7 and Comparative Example 3 In Example 6, the type and amount of the (meth)acrylate monomer, organic peroxide, chlorophylls, or reducing agent were changed as shown in Table 1, and the other conditions were the same as in Example. Table 1 shows the test results when the test was carried out in exactly the same manner as in Example 6.

Example 8 (Preparation of (meth)acrylate monomer emulsion) (meth)
) A (meth)acrylate monomer emulsion was obtained under exactly the same conditions as in Example 6, except that NKBPE-200 was used as the acrylate monomer.

(Encapsulation of organic peroxide) Benzoyl peroxide capsules 5 were prepared under the same conditions as in Example 6 except that the scale was 1/3 times that of Example 6.
1.2 g was obtained.

(Preparation of adhesive composition) The total amount of the (meth)acrylate monomer emulsion obtained above, 40 g of encapsulated organic peroxide (containing 10 g as benzoyl peroxide), 7 g of dimethyl para-toluidine, and chlorophyll. 5 g was put into a 21 beaker and stirred for 5 minutes at 200 rpm using a homogenizer to obtain an aqueous adhesive composition.

Table 2 shows the results obtained for the composition according to the evaluation method described above.

Examples 9 to 15, Comparative Example 4 The types and amounts of (meth)acrylate monomers, organic peroxides, chlorophylls, or reducing agents on the example day were changed as shown in Table 2, and other conditions were Table 2 shows the test results of the adhesive composition obtained in exactly the same manner as in Example 8.

(C) Effects of the Invention The adhesive composition of the present invention has a long pot life even under harsh conditions of high temperatures and has great adhesion ability to various materials even under harsh conditions. .

The adhesive composition of the present invention is suitable for use in fields where it is precoated on a metal material to form a coating film of the adhesive composition, for example, as an adhesive for locking screws.

Claims (1)

[Claims] 1. 0.2 to 1 part of organic peroxide per 100 parts by weight of a monomer having an acryloyl group and/or a methacryloyl group
An adhesive composition containing 0 parts by weight and chlorophyll or a metal substituted product of chlorophyll.