JPH07268310A - Cold-setting two pack type adhesive - Google Patents

Abstract

PURPOSE:To obtain the subject adhesive useful for bonding outdoor structures such as various kinds of building materials, having excellent cold-setting properties, adhesiveness and flexibility, containing no solvent, comprising a specific (meth)acrylic monomer, a polyisocyanate compound, a polyol, a polymerization initiator and a reaction promoter. CONSTITUTION:This adhesive comprises (A) a (meth)acrylic monomer containing a tertiary amino group and OH such as an addition reaction product of glycidyl (meth)acrylate and a compound containing a primary or a secondary amino group, (B) a polyisocyanate compound such as a terminal NCO urethane prepolymer obtained from a (modified) aromatic polyisocyanate and an active hydrogen-containing compound having 50-5,000 molecular weight, (C) a polyol, (D) a radical polymerization initiator and (E) a reaction promoter such as cobalt naphthenate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention does not contain an organic solvent, and the curing reaction proceeds even without heating, and a strong adhesive force (tensile shear strength) and flexibility can be obtained. Liquid adhesives. In particular, it is an adhesive suitable for bonding FRP (glass fiber today or plastic) structures to each other and FRP and other materials.

[0002]

2. Description of the Related Art Conventional adhesives are classified into solvent type and various two-component curing type adhesives.

[0003]

The solvent type has many problems in workability such as suction of vapor by human body and danger of fire, and volume contraction is observed after the solvent is vaporized. On the other hand, the two-component curing type does not have such drawbacks, but heating is necessary to ensure the curing, and there is no heating equipment,
In an environment where the heating device cannot be used, for example, in outdoor work, it takes a long time to complete the curing.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention are concerned with a two-pack type adhesive which does not contain a solvent and which undergoes a curing reaction at room temperature without heating and has both a strong adhesive force and flexibility. As a result of diligent study, by combining the urethanization reaction and the radical polymerization reaction, the urethane skeleton has excellent flexibility, and the acrylic skeleton has excellent tensile shear strength.
Moreover, it was found that radical polymerization is induced at room temperature and the urethanization reaction is completed by the heat of polymerization without heating, and the adhesive of the present invention was reached.

That is, according to the present invention, a (meth) acrylic monomer (A) having a tertiary amino group and a hydroxyl group, a polyisocyanate compound (B), a polyol (C), a radical polymerization initiator (D) and a reaction accelerator ( It is a room temperature curable two-component adhesive characterized by comprising E).

In the present invention, the (meth) acrylic monomer (A) having a tertiary amino group and a hydroxyl group is, for example, an addition reaction product of a compound having a primary or secondary amino group and glycidyl (meth) acrylate. A glycidylamine compound obtained by reacting a compound having a primary or secondary amino group with epichlorohydrin,
Further addition reaction of (meth) acrylic acid, 1
1 or more primary amino groups or 2 or more 2 in the molecule
Partial (meth) acrylate of a product obtained by adding alkylene oxide (having 2 to 4 carbon atoms) to a compound having a primary amino group (the number of added moles: usually 1 to 20), and one or more primary amino groups in one molecule. Or an amino group-containing glycidyl ether compound obtained by the reaction of an alkylene oxide (carbon number 2 to 4) adduct (the number of moles added: usually 1 to 20) of a compound having two or more secondary amino groups with epichlorohydrin. In addition, those obtained by addition reaction of (meth) acrylic acid are also included. Of these, the addition reaction product is preferred.

Specific examples of the compound having a primary or secondary amino group in the above (1) include (1) aromatic amine compounds [aniline, o-, m- or p-toluidine, o-, m- or p- Phenylenediamine, 2, 4
-Or 2,6-tolylenediamine, diaminodiphenylmethane, N-alkyl (alkyl having 1 to 8 carbon atoms) aniline, p-aminopyridine, condensates of these formalins, etc.]; (2) Aliphatic amine compound [methylamine ,
Alkylamines (C1-8) such as ethylamine, isopropylamine, n-butylamine, isobutylamine, cyclohexylamine, dialkylamines (carbons such as dimethylamine, diethylamine, diisopropylamine, di-n-butylamine, diisobutylamine, dicyclohexylamine) 2-16), ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, iminobispropylamine and other (poly) alkylenepolyamines (carbon number 1-8), monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, etc. Mono- or dialkanolamines (having 1 to 4 carbon atoms), etc.]; (3) Aralkylamines such as benzylamine, xylylenediamine; and these 2 Mixture of the above, and the like.
Among those exemplified in (1) to (3), preferable ones are aniline, o-, m- or p-toluidine and monoalkylamines having 1 to 8 carbon atoms.

The tertiary amino group present in (A) of the present invention accelerates the urethanization reaction between the active hydrogen group in each component constituting the curable composition and the isocyanate group of the polyisocyanate compound (B). .

In the present invention, in addition to (A), 3
You may use together (meth) acrylic-type monomer (A2) which has a primary amino group and does not have a hydroxyl group, and / or (meth) acrylic-type monomer (A3) which has a hydroxyl group and does not have an amino group.

As the (meth) acrylic monomer (A2), an alkylene oxide (having 2 to 4 carbon atoms) is added to a compound having a primary or secondary amino group (the number of added moles: usually 1 to 20). An example is (meth) acrylate, which is a completely esterified product. This first grade or 2
Examples of the compound having a primary amino group include (1) to (3) exemplified in (A).

Further, the (meth) acrylic monomer (A
Examples of 3) include partial (meth) acrylates of polyhydric alcohols and glycidyl ethers of polyhydric alcohols reacted with (meth) acrylic acid. Examples of the polyhydric alcohols used in the above include the following (a) to (c). (A): Alkylene glycol [ethylene glycol,
Propylene glycol, 1,4-butanediol, 1,
3-butylene glycol, neopentyl glycol,
1,6-hexanediol, etc.], and dihydric alcohols such as cyclohexanediol, cyclohexanedimethanol, bisphenol A, bisphenol S, and naphthalenediol. (B): Trivalent or higher alcohols such as glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylit, mannitol, glucose, fructose and sucrose. (C): An alkylene oxide (C2-4) adduct of (A) or (B).

As the polyisocyanate compound (B) in the present invention, aromatic polyisocyanate [diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), polyphenyl polymethylene polyisocyanate (crude MDI), naphthalene diisocyanate (NDI), etc. ]; Aliphatic polyisocyanate [1,6-hexamethylene diisocyanate (HD
I), lysine diisocyanate (LDI), etc .; alicyclic polyisocyanate [isophorone diisocyanate (IPDI), dicyclohexyl diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, etc.]; aromatic aliphatic polyisocyanate [xylylene diisocyanate (XDI), Tetramethylxylene diisocyanate (TMXDI), etc.]; modified products thereof (buret group, isocyanurate group, carbodiimide group, oxazolidine group-containing modified product, trimethylolpropane adduct, etc.); and polyisocyanate thereof and molecular weight 50 to 5 Included are urethane prepolymers having terminal isocyanate groups consisting of 1,000 active hydrogen-containing compounds. The urethane prepolymer having a terminal isocyanate group can be obtained by reacting the above-mentioned polyisocyanate with a polyol or polyamine having two or more active hydrogens such as hydroxyl groups and amino groups. As this polyol, those mentioned below as the polyol (C) can be used. Aromatic polyisocyanates, modified products thereof, and urethane prepolymers are preferable because they have excellent strength physical properties as polyurethane and high reactivity as compared with other aliphatic or alicyclic polyisocyanate-based compounds. When using an aliphatic or alicyclic polyisocyanate system with low reactivity, urethane reaction of organometallic compounds (dibutyltin laurate, tin octenoate, lead octenoate, etc.) and amines (triethylamine, triethylenediamine, etc.) It is necessary to use a catalyst together. MDI is a solid at room temperature,
Further, TDI is not used as it is because steam is harmful, and it is usually used as a modified product or a prepolymer thereof. From the viewpoint of workability, the polyisocyanate compound of the present invention preferably has a low viscosity as one component of the two-component adhesive. Further, when a modified product or prepolymer having 3 or more isocyanate groups in the molecule is used, the crosslink density becomes high.

The polyol (C) in the present invention includes low molecular weight polyhydric alcohols and high molecular weight polyols. As the low molecular weight polyhydric alcohol, the above-mentioned (A
The polyhydric alcohols (a) to (c) and the mono-, di- or tri-alkanolamines exemplified in the item 3) are included. As the polymer polyol, various polyester polyols, polyether polyols and other polymer polyols can be used. Examples of the polyester polyol include an acid component such as an aliphatic dicarboxylic acid such as adipic acid and sebacic acid, an aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid, and a carbon number of 2 to 2 such as ethylene glycol, propylene glycol and neopentyl glycol. Polyester polyols having an aliphatic diol of 6 or ether glycols such as diethylene glycol and dipropylene glycol and spiroglycols as diol components; and polycaprolactone polyols. Examples thereof include adipate-based polyols such as polyethylene adipate polyol, polyethylene propylene adipate polyol, and polybutylene adipate polyol; terephthalic acid-based polyols (for example, Toyobo Co., Ltd., trade name Byron); polycaprolactone polyols (for example, Daicel, trade name Praxel). To be Further, as the polyether polyol,
Examples thereof include polyoxyethylene polyols, polyoxypropylene polyols, polyoxytetramethylene polyols, and random and block copolymers thereof. In addition, examples of other polymer polyols include polycarbonate polyol and polybutadiene polyol. These polyols may be used in combination of two or more kinds of low molecular weight polyhydric alcohol and high molecular weight polyol. The number of hydroxyl groups in the molecule of the polyol (C) used in the present invention is 2 or more, and in particular, when a resin having 3 or more hydroxyl groups is used in combination, the coating film hardness increases. Further, although the molecular weight is not particularly limited, when a low molecular weight polyol is used, the coating film hardness is increased, and conversely, when a high molecular weight polyol is used, flexibility can be imparted.

In the present invention, a radical polymerization initiator is used in combination with a reaction accelerator at room temperature to initiate the radical polymerization reaction and complete the urethanization reaction by the heat of polymerization to cure the resin. It is necessary to use it.

As the radical polymerization initiator (D) of the present invention, a peroxide which generates radicals by heat can be used. As the peroxide, diacyl peroxide type [dibenzoyl peroxide, lauroyl peroxide, etc.]; dialkyl peroxide type [di-tert-butyl peroxide, dicumyl peroxide, etc.]; peroxy ester type [tert-butyl Peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, etc.]; Ketone peroxide type [methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.]; Peroxydicarbonate type [bis (4-tert
-Butylcyclohexyl) peroxydicarbonate,
Diisopropyl peroxydicarbonate, etc.]; Peroxyketal-based [1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, 2,2
-Bis (tert-butylperoxy) octane, etc.] and the like. These radical polymerization initiators (D) are
It is preferable that the decomposition temperature is significantly lowered by the influence of the reaction accelerator (E) described later. For example, peroxyester-based,
It is known that the ketone peroxide type has a significantly lower decomposition temperature when combined with an organic acid metal salt such as cobalt naphthenate. Further, the diacyl peroxide type is easily affected by amines such as dimethylaniline.

Another feature of the present invention is that the tertiary amino group in (A) of the present invention accelerates the decomposition of the peroxide, so that a rapid curing reaction proceeds.

As mentioned above, in the adhesive of the present invention,
A reaction accelerator (E) is contained in order to increase the reaction rate of the radical polymerization reaction. As this accelerator, metal salts of organic acids (cobalt naphthenate, magnesium naphthenate,
Cobalt acetoacetate, etc.), tertiary amines (dimethylaniline, etc.), quaternary ammonium salts, etc. Further, a promoter such as β-diketone (acetylacetone, dibenzoylmethane, etc.) which enhances the effects of the radical polymerization initiator and the reaction accelerator can be used. Further, the combined use of a reaction accelerator for the urethanization reaction of the isocyanate group and the hydroxyl group that occurs subsequent to the radical polymerization is also effective in shortening the curing time.

The viscosity of the adhesive of the present invention can be adjusted by using another vinyl monomer (F) in combination.

Other vinyl monomers (F) include (meth) acrylates obtained by completely esterifying the above-mentioned polyhydric alcohols (a) to (c); (meth) acrylates of aliphatic monohydric alcohols; styrene. Aromatic vinyl compounds such as α-methylstyrene, o-, m- or p-methylstyrene and divinylbenzene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; itaconic acid and its esters, (meth) Examples thereof include acrylonitrile.

In the cured composition of the present invention, the amount of the polyisocyanate compound (B) used is such that the hydroxyl group-containing compound (A), (A3) or (C) is the isocyanate of (B) with respect to the hydroxyl group. Molar ratio of groups (NCO group / O
H group) is usually 0.7 to 1.2, preferably 0.9 to
The range is 1.1.

The amount of the polyol (C) used varies depending on whether the low molecular weight polyhydric alcohol or the high molecular weight polyol is used (A) 1.
It is usually 10 to 200 parts by weight, preferably 20 to 100 parts by weight, relative to 00 parts by weight.

The amount of radical polymerization initiator (D) used is
It is usually 0.1 with respect to a total of 100 parts by weight of (A) to (C).
10 to 10 parts by weight, preferably 0.2 to 5 parts by weight.

The amount of the reaction accelerator (E) used varies depending on the catalyst system used, but the total amount of (A) to (C) is 100.
It is usually 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, based on parts by weight.

The amount of the other vinyl monomer (F) to be used depends on the viscosity of the blended liquid, but the total amount of (A) to (C) is 1
It is usually 0 to 300 parts by weight with respect to 00 parts by weight.

In the adhesive of the present invention, the components that normally react with each other are divided into a mixture of two liquids, and the two liquids are mixed and used prior to application to an adherend.

As a method of dividing into a mixture of two liquids, for example, the first liquid is a mixture of a (meth) acrylic monomer (A) and a polyol (C) reaction accelerator (E), and the second liquid is a polyisocyanate. A method of preparing a mixture of the compound (B) and the radical polymerization initiator (D) can be mentioned. Do not combine (A), (A3) and (C) having a hydroxyl group and (B) having an isocyanate group in the same formulation liquid in advance. The radical polymerization initiator (D) is a vinyl monomer (meth) acrylic monomer (A),
Do not combine (A2), (A3), (F) and the reaction accelerator (E) in the same formulation liquid in advance.

The method of applying the adhesive of the present invention is arbitrary, and examples thereof include various coaters, spraying, brush coating, dipping and the like.

The adherend to which the adhesive of the present invention is applied is not particularly limited, but it may be an inorganic building material such as FRP, plastic film / sheet / pipe, glass / ceramic / slate, woodworking material, various metal pipes, etc. It is suitable for outdoor work where it is difficult to bond or heat outdoor structures such as bars and plates. It is especially suitable for bonding large objects that require strength.

The pot life after mixing the two liquids of the adhesive of the present invention varies depending on the constitution and ratio of each component and can be adjusted by the user depending on the usage, but it is usually several minutes to several hours. If the initial curing starts after several hours, the clamp or the like for fixing the adherend may be removed, but it takes several days until the adhesive strength is sufficiently exhibited.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Parts and% are parts by weight and% by weight, respectively.
Represents The abbreviations for the main raw materials used are as follows. Raw materials used NP: Light ester NP (Kyoeisha fat and oil, neopentyl dimethacrylate) PA-305: Neomer PA305 (Sanyo Chemical Co., Ltd. polyoxypropylene diacrylate) PMN: Permek N (Nippon Yushi and fat: Methyl ethyl ketone peroxide)

Production Example 1 Glycidyl methacrylate 284 was placed in a glass reactor equipped with a dropping funnel, a thermometer, a reflux condenser and a stirring rod.
N-butylamine 73 at a temperature of 30 ° C. or lower with stirring.
Part was dropped from the dropping funnel over 2 hours, and after the dropping was completed, 5
It was aged at 0 ° C. for 3 hours and at 80 ° C. for 3 hours to obtain a transparent liquid reaction product. 1 part of 1,4-butanediol in 30 parts of this product
A first liquid A1 was prepared by mixing 0 part, 20 parts of NP, and 0.5 part of dimethylaniline. On the other hand, in a glass reactor equipped with a thermometer, a stir bar, and a nitrogen introduction tube, 250 parts of a polyester diol having a molecular weight of 500 obtained from adipic acid and 1,4-butanediol and 223 parts of isophorone diisocyanate were charged, 110 with stirring under nitrogen stream
The mixture was heated to 0 ° C. and reacted for 7 hours to obtain an NCO group-terminated urethane prepolymer. A second liquid B was prepared by adding 5 parts of PMN to 100 parts of this urethane prepolymer. As described above, a composition of the present invention consisting of the first liquid A1 and the second liquid B was obtained.

Production Example 2 284 parts of glycidyl methacrylate were charged in the same reactor as in Production Example 1, and the temperature was raised to 90 ° C. with stirring. To this product, 93 parts of aniline was added dropwise from a dropping funnel over 2 hours, and after completion of the dropping, the mixture was aged at 120 ° C. for 6 hours to obtain a yellow transparent liquid reaction product. To 30 parts of this product, 0.5 part of cobalt naphthenate, 10 parts of 1,4-butanediol and NP
20 parts were compounded to prepare a first liquid A2. The second liquid B is
It was created in the same manner as in Production Example 1. From the above, the first liquid A
A composition of the present invention consisting of the second liquid and the second liquid B was obtained.

Production Example 3 30 parts of the reaction product of aniline and glycidyl methacrylate produced in Production Example 2, 0.5 parts of cobalt naphthenate, 1,
A first liquid A3 was prepared by mixing 10 parts of 4-butanediol and 20 parts of PA-305. The second liquid B was prepared in the same manner as in Production Example 1. As described above, a composition of the present invention consisting of the first liquid A3 and the second liquid B was obtained.

Comparative Preparation Example 2 Preparation Example 2 except that the methacrylic acid adduct of diethylene glycol diglycidyl ether was used in place of the reaction product of aniline and glycidyl methacrylate in the second liquid of A2, and cobalt naphthenate was not added. Similarly, the first liquid A4 was prepared. The second liquid B was prepared in the same manner as in Production Example 1. According to the above, the first liquid A4 and the second liquid A4
A comparative composition consisting of two liquids, Liquid B, was prepared.

Examples 1 to 3 and Comparative Examples The first liquids A1 to 4 and the second liquid B of Production Examples 1 to 3 and Comparative Production Example were mixed at the mixing ratio shown in Table 1, and FRP was applied using an applicator. After applying a thickness of 25 μm on the plate, it is attached to another FRP plate so that the tensile shear strength can be measured, and it is applied at room temperature for 3
After standing for one day, these tensile shear strengths were measured. The results are shown in Table 1.

[0036]

[Table 1]

Physical property measuring method Tensile shear strength (kg / cm2): FRP having a thickness of 3 mm obtained by compression molding of a sheet molding compound
(100 × 25 × 3 mm), JIS K-685
Measured according to 0.

[0038]

EFFECT OF THE INVENTION The room temperature curable two-component adhesive of the present invention does not contain a solvent, and the curing reaction proceeds at room temperature without heating.
It is a two-component adhesive that has both strong adhesive strength and flexibility. This is because the urethane skeleton is excellent in flexibility by using the urethanization reaction and the radical polymerization reaction together,
It is presumed that the acrylic skeleton has excellent tensile shear strength, and radical polymerization occurs at room temperature without heating, and the heat of polymerization completes the urethanization reaction.
The adherend to which the adhesive of the present invention is applied is not particularly limited, but it is an inorganic building material such as FRP, plastic film / sheet / pipe, glass / ceramic / slate, woodworking material, pipe / rod / plate of various metals. It is suitable for outdoor work where it is difficult to adhere or heat the outdoor structure. It is especially suitable for bonding large objects that require strength.

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Claims (3)

[Claims] 1. A compound having a tertiary amino group and a hydroxyl group (meth).
Acrylic monomer (A), polyisocyanate compound (B), polyol (C), radical polymerization initiator (D)
And a room temperature curable two-component adhesive characterized by comprising: and a reaction accelerator (E). 2. The (meth) acrylic monomer (A)
Is an addition reaction product of glycidyl (meth) acrylate and a compound having a primary or secondary amino group.
The room temperature curable two-component adhesive described. 3. The polyisocyanate compound (B) is
Aromatic polyisocyanate and its modified products (carbodiimide group, biuret group, allophanate group, urea group,
Isocyanurate group, oxazoline group-containing modified product, trimethylolpropane adduct), and molecular weight 5 thereof
Terminal NC from 0-5,000 active hydrogen containing compounds
The room temperature curable two-component adhesive according to claim 1 or 2, which is one or more selected from the group consisting of urethane prepolymers having O groups.