JPS61203168A - Polyurethane composition - Google Patents

Abstract

PURPOSE:To improve bond performance to adherends, by blending a reaction product between an alkoxysilyl group-contg. amine compd. and a carbonyl compd. with an active isocyanate group-contg. urethane prepolymer product. CONSTITUTION:A reaction product of an amine compd. contg. at least one alkoxysilyl group of formula I (wherein R<1>, R<2> may be the same or different and each is a 1-4C alkyl; n is 0, 1, 2) with a carbonyl compd. of formula II (wherein R<4>, R<5> may be the same or different and each is a 1-14C alkyl, a 6-12C aryl, a 1-4C alkoxy) or a mixture thereof is blended with a reaction product of a polyol component contg. at least two active hydrogen atoms per molecule with an excess of a polyisocyanate compd. Examples of said amine compd. and said carbonyl compd. are gamma-amino-propyltriethoxysilane and acetylacetone.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to novel polyurethane compositions suitable for applications such as adhesives, sealants, etc. The present invention relates to a polyurethane composition containing a reaction product of a silyl group-containing amine compound and a carbonyl compound or a mixture thereof, which has excellent adhesion performance to adherends.

Conventional technology and problems to be solved Polyurethane resins have a high degree of freedom in molecular design and can have a wide range of physical and chemical properties, from viscous liquids to rubber elastic bodies and even tough plastics, so they are used as civil engineering materials and building materials. It is an indispensable material for plastic moldings, plastic foam moldings, rubber processed products, etc. in fields such as automobile parts and electrical materials, as well as paints, adhesives, sealants, etc., and has been actively researched and developed. Various polyurethane resin compositions have been put into practical use.

These polyurethane resins can be used as adhesives, sealants,
When used in paints, coating materials, etc., the composition is required to have excellent adhesion and adhesion to the adherend or object to be coated.

However, in the known polyurethane resin compositions, inorganic materials such as metal, glass, concrete, etc.
Generally, sufficient adhesion and adhesion cannot be obtained for organic materials such as plastics, rubber, and various paint-coated surfaces, so polyisocyanate compounds, silane coupling agents, or A method has been adopted in which a so-called adhesion promoting primer treatment is applied by applying an organic solvent solution such as a titanate coupling agent, and then a polyurethane resin composition is applied and processed. However, this method has disadvantages such as increased labor involved in adhesion work, painting work, etc. due to primer treatment, and increased production and processing costs.

On the other hand, in order to improve the adhesive strength and adhesion of polyurethane resin compositions, methods have been proposed in which the content of active isocyanate groups is increased or an adhesion promoter such as a silane coupling agent is added. However, this method has problems such as decreased storage stability and foaming.
There are also limits to adhesion to specific adherends such as stainless steel and aluminum, and the cost is also high, making it unsatisfactory in practice. In addition, aminoalkoxysilane compounds as the above-mentioned adhesion promoter exhibit excellent adhesion-improving ability, but on the other hand, the active hydrogen of the amino group instantly reacts with the active isocyanate group in polyurethane to induce a crosslinking reaction. formulation as the same composition is extremely difficult. Furthermore, although it has been proposed to use epoxyalkoxysilane or mercaptoalkoxysilane, the improvement in adhesion is often insufficient.

In view of the above-mentioned problems with conventionally known polyurethane resin compositions, the present inventors have conducted intensive research to obtain a polyurethane resin composition with improved adhesion and adhesion. The considered amino compound having an alkoxysilyl group is reacted with a carbonyl compound in advance, and the primary and/or secondary amino group is ketiminated or enaminated with the carbonyl group to form a reaction product. The inventors have discovered that a polyurethane composition having excellent adhesion performance to adherends can be obtained by this method, and have completed the present invention.

Structure and effect of the invention That is, the present invention provides a reaction product of a polyol component having two or more active hydrogens in one molecule and an excess amount of a polyisocyanate compound, and at least one of the formulas in one molecule: % formula % [wherein R1 and R2 are the same or different and each represents an alkyl group having 1 to 4 carbon atoms, and n means 0.1 or 2] and an amine compound having an alkoxysilyl group represented by the formula: % Formula % [In the formula, R4 and R5 are the same or different and each means an alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms] The present invention provides a polyurethane composition characterized by comprising a reaction product with a carbonyl compound represented by the above formula or a mixture thereof.

Polyol components having two or more active hydrogen atoms in one molecule used in the present invention include polyether polyols, polyester polyols, polybutadiene polyols containing terminal hydroxyl groups, butadiene acrylonitrile copolymer polyols containing terminal hydroxyl groups, acrylic polyols, and castor oil. derivatives, tall oil derivatives, etc.

Examples of the polyisocyanate compound to be reacted with the polyol component include aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine methyl ester diisocyanate, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, and hydrogenated tolylene diisocyanate; Aromatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, xylylene diisocyanate, and mixtures thereof are included. Particularly preferred polyisocyanate compounds are aromatic polyisocyanates, such as TDI and MDI.

The desired urethane prepolymer product is obtained by reacting the polyol component and the polyisocyanate compound such that the polyisocyanate compound has one or more active isocyanate groups relative to the hydroxyl group of the polyol component. For example, the ratio of both components is 1.3≦N COlo H≦1
The reaction is carried out at 70 to 100° C. for several hours. In this reaction, conventional catalysts, plasticizers and solvents can be used. The urethane prepolymer product obtained is adjusted so that the active isocyanate group content is in the range of 0.5 to 15%, and the most preferable content is selected within this range depending on the desired physical properties and use. For example, 3-15% for adhesives, paints, etc., and 0.5-5% for sealants.
．． 0% is desirable.

In addition, depending on the function and use of the polyurethane composition,
The polyol component to be reacted with the polyisocyanate compound is appropriately selected. For example, when used as an adhesive, polyether polyols, polyester polyols, or polybutadiene homopolymers or copolymers containing terminal hydroxyl groups are desirable because they improve adhesive performance. Further, when used as a sealing material, it is mainly composed of polyether polyol, and when used in combination with acrylic polyol etc., a material with excellent fluidity and workability can be obtained.

In addition, when used in paints, if polyester polyol is used as the main component or acrylic polyol is used in combination,
Excellent durability.

In the present invention, the amine compound having at least one alkoxysilyl group in one molecule includes known ones, preferably, for example, the formula: [wherein R1 and R'' are the same as above, R3 has 1 carbon
~4 divalent hydrocarbon groups (e.g. methylene, ethylene, propylene, butylene), Z is a hydrogen atom or an aminoalkyl group having 1 to 4 carbon atoms (e.g. aminomethyl, aminoethyl, aminopropyl, aminobutyl) , and m means 0.1 or 2]. Specifically, N-(β-aminoethyl)aminomethyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyljethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, Ethoxysilane, N-(β-aminoethyl)-γ
-aminopropylmethyldimethoxysilane and the like.

As another example of the amine compound, the excess amount of the above aminoalkylalkoxysilane compound (I) and the following formula: % formula % () [wherein R1, R1, R3 and ■ are the same as above, G is glycidoxy or refers to an epoxycyclohexyl group] Compounds obtained by subjecting an epoxyalkylalkoxysilane compound represented by the following to a heating reaction with stirring are mentioned.

This reaction is performed using an aminoalkylalkoxysilane compound (
It is desirable to use 1 mol of I) and 0.9 mol or less, preferably 0.1 to 0.6 mol, of the epoxyalkylalkoxysilane compound (n). As the epoxyalkylalkoxysilane compound (If), for example, γ-
Glycidoxypropyldimethylethoxysilane, γ-glycidoxypropylmethyljethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3゜4-
epoxycyclohexyl)ethyltrimethoxysilane,
Examples include β-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane.

Instead of the epoxyalkylalkoxysilane compound reacted with the excess amount of the aminoalkylalkoxysilane compound, a normal epoxy resin having one or more epoxy groups in one molecule, or a butadiene homopolymer or copolymer containing an epoxy group can be used. It can also be used.

Moreover, the above-mentioned urethane prepolymer having an sardine acid group can also be used.

The amine compounds mentioned above require active hydrogen bonded to the nitrogen atom, so if they are blended as is, they quickly react with the active isocyanate groups in the urethane prepolymer product to form urea bonds. In order to crosslink and cure, in the present invention, this is reacted with a carbonyl compound in advance to cause a dehydration condensation reaction between the primary and/or secondary amino group in the amine compound and the carbonyl group, and then the carbonyl group is cured in the absence of water. The so-called enamine group, in which the amino group is blocked with
It is formulated as a compound having a ketimine group.

Since the reaction product is hydrolyzed by moisture and water vapor in the air and returns to the amine compound and carbonyl compound, it is necessary to store the product under sufficient moisture protection before use and after blending.

The carbonyl compound used in the present invention is particularly preferably represented by the formula: %Formula%() [wherein R4 and R5 are the same or different and each represents an alkyl group having 1 to 16 carbon atoms (for example, methyl, ethyl, propyl, butyl, heptyl , hexyl, octyl, nonyl, decyl, undecyl, hexadecyl, etc.),
means an aryl group having 6 to 12 carbon atoms (e.g., phenyl, tolyl, hexyl, naphthyl, etc.) or an alkoxy group having 1 to 4 carbon atoms (e.g., methoxy, ethoxy, propoxy, butoxy, etc.) -dicarbonyl compounds, specifically acetylacetone, methyl acetoacetate, ethyl acetoacetate, dimethyl malonate, diethyl malonate, methylethyl malonate, dibenzoylmethane, and the like.

The reaction between the above-mentioned amine compound and β-dicarbonyl compound is carried out under the same conditions as a normal dehydration condensation reaction between an amine and an aldehyde or ketone, for example, in the presence of a water-absorbing agent or by distilling water off under heating under reflux. It is done while More specifically, a β-dicarbonyl compound (where one of the two keto groups is reacted) in a stoichiometrically equivalent or excess amount of the amine compound is added to an appropriate organic compound such as toluene, xylene, benzene, etc. A water absorbing agent such as a molecular sieve or anhydrous magnesium sulfate is added to a solvent, and the mixture is reacted at room temperature or under heating while stirring.

The reaction product of the amino group-blocked amine compound obtained by the above method and the carbonyl compound may be used alone or as a mixture of two or more.

The reaction product or mixture in which the amino group is blocked,
The desired polyurethane composition can be obtained by incorporating it into the urethane prepolymer product in a proportion of 0.05 to 5.0%. If this proportion is less than 0.05%, the desired improvement in adhesion will not be achieved sufficiently, while if it exceeds 5.0%, the alcohol produced by hydrolysis of the silyl ether group will react with the isocyanate, so polyurethane This is not preferred because the curability of the composition may be inhibited.

The polyurethane composition of the present invention may contain various other commonly added additives such as fillers, plasticizers, solvents, catalysts,
Anti-aging agents, pigments, etc. may be added.

Examples of the inert filler include carbon black, calcium carbonate, clay, and talc, which may be used alone or in combination at a ratio of 20 to 70%.

Examples of plasticizers include phthalic acid esters such as dioctyl phthalate, butylbenzyl phthalate, and dinonyl phthalate, benzoic acid esters such as diethylene glycol dibenzoate and ethylene glycol monobutyl ether benzoate, partially hydrogenated terphenyl, and carbonized alkyl polycyclic aromatics. Examples include hydrogen and chlorinated paraffins, which are blended in an amount of 20% or less. In addition, as a solvent, aromatic hydrocarbons such as toluene and xylene,
Includes esters, ketones, ethers, etc. Note that these fillers, plasticizers, solvents, and the like need to be inert to the polyurethane resin and also need to be anhydrous, so it is preferable to dry and dehydrate them.

Catalysts for accelerating curing include N-alkylbenzylamine, N-alkylmorpholine, N-alkylaliphatic polyamine, N-alkylpiperazine, triethylenediamine, naphthenic acid or heavy metals such as tin, lead, cobalt, manganese and iron. Examples include octate, dibutyltin dilaurate, and dibutyltin maleate.

Furthermore, silicic anhydride, antioxidants, ultraviolet absorbers, anti-sagging agents, etc. may be added as appropriate.

The polyurethane composition of the present invention may be prepared in a so-called two-component type, but even if it is stored for a long period of time after adding surrounding components, the composition may increase in viscosity or gel due to hydrolysis of the amine compound. Because it can be held stably without
Preferably, it is prepared in a one-component form from the viewpoint of ease of handling and economical aspects. The preparation of this composition is carried out according to a conventional method. For example, the polyol component and the polyisocyanate compound are first heated and reacted to form a urethane prepolymer using a closed stirring mixer equipped with a heat insulating jacket and which can be replaced with nitrogen gas. To this, pre-dried fillers, pigments, plasticizers, solvents, and other additives are sequentially added, and finally, a reaction product of an amine compound and a carbonyl compound or a mixture thereof is added, and the mixture is stirred and kneaded. Product.

The polyurethane composition of the present invention can be suitably used for adhesives, sealants, brimers, paints, coating materials, etc., but it can also be used satisfactorily for various other applications for which ordinary polyurethane resin compositions are used. used.

Depending on the use of the polyurethane composition, the types of ingredients,
``The dosage may vary within the scope of the present invention.

For example, when used in adhesives, paints, primers, etc., a tough and hard product is desired, and the active isocyanate group content of the urethane prepolymer product should be in the range of 7 to 15%, and it is also used in sealants, coating materials, etc. In some cases, the activation of the urethane prepolymer is used to provide rubber elasticity with high elongation in order to provide vibration isolation, and to suppress foaming due to carbon dioxide gas generated by reaction with moisture during the curing process. The isocyanate group content is preferably about 0.5 to 5.0 parts.

According to the composition of the present invention, adhesion to metals that are said to be difficult to adhere to with conventionally known compositions of this type, particularly stainless steel, aluminum plates, zinc-treated steel plates, etc., is improved, and in addition, amino groups are blocked. After application of the composition, the amine compound is dissociated by moisture and unblocked, and reacts with the isocyanate to develop a crosslinking effect.
It also has the advantage of improving the physical properties of treated products.

Next, the composition of the present invention will be explained in more detail with reference to Examples. In the examples, "parts" mean parts by weight.

Example 1 (a) Production of urethane prepolymer 100 parts of hydroxyl-terminated polybutadiene polyol (PolybdR45HT, manufactured by Idemitsu Petrochemical Co., Ltd.), diphenylmethane-4,
22 parts of 4°-diisocyanate was charged into a reaction tank equipped with a heat-insulating jacket that could be heated and replaced with dry nitrogen gas, and reacted at 80°C for 5 hours with stirring to obtain a solution containing 3.1% of active isocyanate groups. Obtain a urethane prepolymer.

(b) Production of amine compound with amino group blocked In a reaction tank purged with dry nitrogen gas, 15% of dehydrated toluene was added.
Add 0 parts, 22.2 parts of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 15 parts of molecular sieve as a water absorbing agent, and gradually add 20 parts of acetylacetone while stirring at room temperature to complete the addition. After that, 4 more
The reaction is allowed to proceed under stirring at room temperature for an hour. After the reaction is completed, the water absorbing agent is removed by suction filtration to obtain a toluene solution of the amino group-blocked amine compound. This solution has an active ingredient content of 22%,
Store in dry condition.

(C) Production of polyurethane composition To 50 parts of the urethane prepolymer obtained in (a) above, calcium carbonate 3 which had been previously dried to a water content of 0.05% or less was added.
0 parts of clay, 1.0 parts of the amine compound solution obtained in (b) above, and 9 parts of xylene are added and mixed with stirring to obtain a polyurethane composition. This composition had a viscosity of 10,000 cps and a viscosity of 12,000 cps after being left at 50° C. for one month in a sealed state, indicating good storage stability.

(d) - Use as a corrugated moisture-curing adhesive (
The polyurethane composition obtained in step C) was coated evenly on a plywood board with a diameter of 25 mm, a length of 100 mm, and a thickness of 3 mm. mm) and 20℃
It was left to stand in a constant temperature and humidity room at /65% RH for 48 hours to cure and harden.

The obtained cured product has a 180° peel strength (initial adhesive strength)
It was 3.0 kg/25 am. 40% of this cured product
The water-resistant adhesive strength was measured by immersing it in water at a temperature of 1 month and found to be 4.0 kg/25 mm.

When a similar test was conducted using a polyvinyl chloride decorative board instead of the stainless steel board, the initial adhesive strength was 5.0 kl? /25mm, water resistant adhesive strength is 4.
It was 0 to 9/25 mm.

Comparative Example 1 Example 1 above. A polyurethane composition was produced in the same manner as in (c) except that the amino group-blocking amine compound was not used, and this composition was used in Examples! , When the adhesive strength to the stainless steel plate was tested in the same manner as in (d), the initial adhesive strength was 1.0 kg/25 mm, and interfacial failure occurred between the stainless steel plate and the adhesive, and the water resistant adhesive strength was At 0.2, the adhesive strength decreased significantly by 9/25 mm.

Example 2 (a) Production of urethane prepolymer Acrylic polyol obtained by polymerizing 130 parts of ethyl acrylate, 5 parts of 2-hydroxyl methacrylate, 2.5 parts of a polymerization initiator, and 40 parts of toluene under heating at 80°C. (Molecular weight 1oooo,
Number of functional groups 2.1) 775 parts and hydrogenated diphenylmethane-4
, 34 parts of 4°-diisocyanate are further reacted for 5 hours to obtain a urethane prepolymer containing 0.7% of active isocyanate groups.

(b) Production of amine compound with amino group blocked 22.1 parts of γ-aminopropyltriethoxysilane and γ
- 7.03 parts of glycidoxypropyltrimethoxysilane (molar ratio, 1:0.3) was added to 150 parts of dehydrated toluene, and the reaction was heated at 50°C for several hours with stirring to eliminate unreacted amino groups and imino groups. A mixture containing an aminoalkoxysilane having the following properties is obtained.

15 parts of molecular sieves were added to a toluene solution of 179.13 parts of the above mixture, and 26 parts of ethyl acetoacetate was added dropwise at room temperature while stirring, and the mixture was stirred at room temperature for 6 hours to react. Obtain a toluene solution of the compound.

(C) Production of polyurethane composition 20 parts of titanium oxide, 25 parts of xylene, and 1.0 part of catalyst were mixed and dispersed in 100 parts of the urethane prepolymer obtained in (a) above using a ball mill for 24 hours to prepare a polyurethane composition. get.

(d) Use as a paint The polyurethane composition (moisture-curable paint) obtained in (C) above was applied to a degreased steel plate to a thickness of about 50μ, and heated at 20°C/65%RH. It was left in an atmosphere for 7 days to cure and harden. Regarding the obtained cured coating film, JIS
5400 (1+nm square, 10
Adhesion was evaluated using 0 frames). As a result, the normal adhesion, the adhesion after water resistance (immersion in water for 7 days), and after 1000 hours of weathering were all good.

Example 3 (a) Production of urethane prepolymer 100 parts of butyl acrylate, 0.5 parts of 2-hydroxyethyl methacrylate
diphenylmethane-4,
33 parts of 4'-diisocyanate are reacted to obtain a urethane prepolymer having 0.9% of active isoneanate groups.

(b) Production of amine compound with amino group blocked N-(β-aminoethyl)-7-
An amino group-blocked amine compound is obtained by mixing and reacting 22.2 parts of aminopropyltrimethoxysilane, 16.4 parts of γ-glycidoxypropyltrimethoxysilane, and 26 parts of ethyl acetoacetate.

(C) - Use as a corrugated moisture-curing adhesive (
Add the above (
3.0 parts of the amine group-blocked amine compound obtained in step b) and 0.5 parts of the catalyst are added and mixed to prepare a wave-type moisture-curable adhesive. Adhesion evaluation: medium 25mm, length 100
Apply it evenly to a plywood board with a thickness of 3 mm and a polyvinyl chloride decorative board of the same shape.
/65% RH for 7 days in a constant temperature and humidity chamber to cure and cure. The 180° peel strength of the obtained cured product was 4.7k.
g/25 mm, and the water resistant adhesive strength after being immersed in water for one month was 4.2 kg/mm.

Claims (1)

[Claims] 1. A reaction product of a polyol component having two or more active hydrogen atoms in one molecule and an excess amount of a polyisocyanate compound, and at least one formula in one molecule: ▲ Numerical formula, chemical formula, There are tables etc. ▼ [In the formula, R^1 and R^2 are the same or different and each is an alkyl group having 1 to 4 carbon atoms, and n is 0 or 1
or 2] An amine compound having an alkoxysilyl group represented by the formula: R^4-CO-CH_2-CO-R^5 [wherein R^4 and R^5 are the same or different, and each Alkyl group having 1 to 16 carbon atoms, 6 to 12 carbon atoms
aryl group or alkoxy group having 1 to 4 carbon atoms] A polyurethane composition comprising a reaction product with a carbonyl compound or a mixture thereof. 2. An amine compound having an alkoxysilyl group has the formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^1 and R^2 are the same or different, and each is an alkyl group having 1 to 4 carbon atoms. , R^3 has 1 carbon number
-4 divalent hydrocarbon groups, Z is a hydrogen atom or an aminoalkyl group having 1 to 4 carbon atoms, and m means 0, 1 or 2] Composition according to item 1. 3. An amine compound having an alkoxysilyl group has the formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^1 and R^2 are the same or different and each is an alkyl group having 1 to 4 carbon atoms. , R^3 has 1 carbon number
~4 divalent hydrocarbon groups, Z is a hydrogen atom or an aminoalkyl group having 1 to 4 carbon atoms, and m means 0, 1 or 2] Less than the equivalent of the aminoalkylalkoxysilane compound represented by Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^1, R^2, R^3 and m are the same as above, G means glycidoxy or epoxycyclohexyl group] Epoxy represented by The composition according to item 1 above, which is a reaction product having a free amino group or imino group with an alkyl alkoxysilane compound.