JPH0619032B2 - Curable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curable composition. More specifically, it relates to a composition which has a long pot life at room temperature and is rapidly cured at a high temperature.

[Conventional technology]

Organic polymers having a reactive silicon-containing group in the molecule are well known, and for example, the following moisture-curable polymer, which forms a siloxane bond between molecules by the moisture in the air to crosslink and cure. An example is coalescence.

(In the formula, R is an organic group, X is a hydrolyzable group such as a carboxyl group, and n is an integer of 0, 1 or 2.) Usually, a curing catalyst is used for curing such a polymer, Many curing catalysts are already known.
Examples thereof include titanate ester compounds such as tetra-n-butoxy titanate, tin carboxylate compounds such as dibutyltin dilaurate and tin dioctylate, and amines.

It is known that an organic polymer having a reactive silicon-containing group can be used as an adhesive (pressure-sensitive adhesive) such as an adhesive tape or an adhesive label. This adhesive is usually
It is produced by coating the above-mentioned organic polymer on a base material such as a tape or a sheet at room temperature, and crosslinking and curing it at a high temperature with moisture in the air. In this manufacturing process, the organic polymer hardly cures during coating on the substrate (expresses that the pot life is long), and it cures as quickly as possible during cross-linking curing at high temperature. It is important in terms of easiness and reduction of manufacturing time. When the above-mentioned polymer is used as a cured product that is cured at a high temperature, not limited to the pressure-sensitive adhesive, the pot life at room temperature is long and it is an important property that the curing proceeds promptly.

The curing catalyst exemplified above is used depending on the purpose and application, but it is a curing catalyst used when the pot life at room temperature is long and quick curing at high temperature is required. So far, no catalyst showing sufficient performance has been known. That is, with conventional curing catalysts, when an attempt is made to obtain a sufficient pot life at room temperature, the curing speed at the actual high temperature is also slowed down, while when an attempt is made to accelerate curing at a high temperature, the room temperature The pot life becomes short, and it is difficult to achieve both pot life and quick curing properties.

[Problems to be solved by the invention]

In view of the circumstances as described above, the present invention has a long pot life at room temperature, and has found a curing catalyst capable of exhibiting a fast curing property at room temperature, and an object thereof is to obtain a curable composition having this property. It is a thing.

[Means for solving problems]

The present invention has at least one reactive silicon-containing group in the molecule and has essentially as a main chain the general formula: —R ¹ —O—.
(Wherein R ¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms), or an alkylene oxide polymer having a repeating unit represented by the formula or at least one reactive silicon-containing group in the molecule. Curing catalyst for 100 parts (part by weight, the same applies below) of organic polymer (A) consisting of an acrylic polymer
The general formula as (B): (In the formula, Q is a group selected from monovalent hydrocarbon groups having 1 to 20 carbon atoms, and each Q may be the same or different) 0.1 ~ 1
Regarding a curable composition characterized by using 0 part, by using such a curable composition, it is possible to combine the contradictory properties of long pot life at room temperature and fast curing at high temperature. It was made because it was found that a remarkable effect can be obtained.

〔Example〕

It has at least one reactive silicon-containing group in the molecule used in the present invention, and has essentially the following general formula as a main chain: —R ¹ —O
-(Wherein R ¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms) having an alkylene oxide polymer having a repeating unit or at least one reactive silicon-containing group in the molecule. The organic polymer (A) made of an acrylic polymer has at least one reactive silicon-containing group per molecule at the terminal or side chain, preferably 1.
An organic polymer having 2 to 6 groups, which has essentially the following general formula as a main chain of the organic polymer: —R ¹ —O— (wherein R ¹ is a divalent hydrocarbon having 1 to 8 carbon atoms). Which is a group) or an acrylic polymer having at least one reactive silicon-containing group in the molecule.

The organic polymer having an alkylene oxide polymer as the main chain of the organic polymer, for example, JP-B-45-36319,
46-12154, 49-32673, JP-A-50-156599, 5
1-73561, 54-6096, 55-13768, 55-82123
No. 55, No. 55-123620, No. 55-125121, No. 55-131021,
It can be obtained by the method proposed in the respective publications such as 55-131022, 55-135135 and 55-137129.

Further, an organic polymer having an acrylic polymer (including an acrylic polymer) as a main chain is disclosed in, for example, JP-B-51-28301.
And Japanese Patent Application Laid-Open No. 57-179210.

The reactive silicon-containing group, for example, a hydrolyzable silicon-containing group having a hydrolyzable group bonded to a silicon atom or a silanol group, in the presence of moisture or a cross-linking agent, if necessary a catalyst or the like is used. It is a group that causes a condensation reaction, and is typically represented by the general formula (1): (In the formula, R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a general formula: (R ′) ₃ SiO— (In the formula, R ′ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. And each R'may be the same or different), a triorganosiloxy group represented by the formula (1), X is a hydrogen group or a hydrolyzable group, and when two or more are bonded, By the way, they may be the same or different, a is 0, 1, 2 or 3, b is 0, 1 or 2, m is 0 or an integer from 1 to 18) It is a group represented. When two or more R ² are included in the general formula (1), they may be the same or different.

When R ² is a hydrocarbon group having 1 to 20 carbon atoms, specific examples thereof include alkyl groups such as methyl group and ethyl group; cycloalkyl groups such as cyclohexyl group; aryl groups such as phenyl group; benzyl group and the like. And the aralkyl group. Further, R ² may be a triorganosiloxy group represented by the general formula: (R ′) ₃ SiO— as described above. Among R ² as described above, a methyl group or a phenyl group is preferable from the viewpoint of easy availability of raw materials.

X in the general formula (1) is a hydrolyzable group in addition to the hydroxyl group, such as a halogen group, a hydride group, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amido group, an aminooxy group, a mercapto group. , Alkenyloxy groups and the like can be exemplified. Of these, an alkoxy group is preferable because it is easy to handle.

In the present invention, when using the organic polymer containing alkylene oxide polymer as the organic polymer (A), the main chain is essentially the general formula of the organic polymer: -R 1 ^-0- (wherein, R ¹ is a divalent hydrocarbon group having 1 to 8 carbon atoms, most of which is most preferable when it is a hydrocarbon group having 1 to 4 carbon atoms. Specific examples of R ¹ , which is a divalent hydrocarbon group having 1 to 8 carbon atoms, include —CH ₂ —, —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ CH ₂ — and so on. The main chain of the organic polymer containing alkylene oxide polymer may consist repeating units of only one kind may be made from two or more repeating units, but especially as R ¹ Is preferred. The molecular weight of the organic polymer containing the alkylene oxide polymer is preferably 500 to 30,000,
More preferably 3000 to 15000, particularly having a hydrolyzable silicon-containing group at the end of the molecule, molecular weight 3000 to 1500
0 is preferable.

In the present invention, an acrylic polymer (including an acrylic copolymer) is used instead of the alkylene oxide polymer.
You may use the organic polymer which has a main chain. Specific examples of the organic polymer having at least one reactive silicon-containing group in the molecule include acrylic acid ester-butadiene copolymer, ethylene-acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid. Any polymer may be used as long as it is a polymer having a rubber-like property such as an acid ester and a reactive silicon-containing group introduced into the polymer. Among these, particularly an organic polymer (A) whose main component is an acrylic acid ester or a methacrylic acid ester,
That is, 50% in the organic polymer (A) (% by weight, the same below)
An organic polymer (A) containing a portion obtained by polymerizing an acrylic acid ester or a methacrylic acid ester, specifically n-butyl (meth) acrylate (n-butyl acrylate and n-butyl methacrylate) The same shall apply hereinafter), 2-ethylhexyl (meth) acrylate, ethyl acrylate, propyl acrylate, isobutyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl ( Polymers or co-polymers containing (meth) acrylate esters of alcohols having 2 to 12 carbon atoms such as (meth) acrylate and n-decyl (meth) acrylate, such as linear, branched, and alicyclic alcohols Organic polymers (A) produced from polymers are preferred.

As the molecular weight of the acrylic polymer having a reactive silicon-containing group, those having a molecular weight of 500 to 100,000 can be used.
The one having a molecular weight of 3000 to 15 is preferable, especially when it has a hydrolyzable silicon-containing group at the molecular end.
000 is preferable.

The organic polymer (A) used in the present invention may be one kind of organic polymer or a mixture of two or more kinds of organic polymers. For example, an organic polymer containing the above-mentioned alkylene oxide-based polymer and an organic polymer in which a reactive silicon-containing group is bonded to an acrylic acid alkyl ester-based polymer may be used in combination, or the above-mentioned alkylene oxide-based polymer may be used. It may be a polymer having a reactive silicon-containing group obtained by polymerizing an alkyl acrylate or the like in the presence of an organic polymer containing

The curing catalyst (B) used in the present invention accelerates curing by rapidly condensing the reactive silicon-containing group of the organic polymer (A) used in the present invention in the presence of water. As a method, it can be obtained, for example, by reacting Q ₂ Sn = 0 and Q ₃ SiOH. Note that Q is the same group as the above-mentioned group, specifically, a methyl group, an ethyl group, an i-propyl group,
n-propyl group, n-butyl group, i-butyl group, n-amyl group, i-amyl group, n-hexyl group, cyclohexyl group, n-octyl group, 2-ethylhexyl group, ularyl group, stearyl group, phenyl Examples include groups.

Specific examples of Q ₂ Sn = O include (CH ₃ ) ₂ Sn = O and (C ₂ H
₅ ) ₂ Sn = O, (C ₄ H ₉ ) ₂ Sn = O, (C ₈ H ₁₇ ) ₂ Sn = O, (C ₆ H ₅ ) ₂ Sn = O, etc., but are not limited thereto. Not a thing.

Further, specific examples of Q ₃ SiOH include, for example, (CH ₃ ) ₃ SiOH,
(C ₂ H ₅ ) ₃ SiOH, (iC ₃ H ₇ ) ₃ SiOH, (C ₄ H ₉ ) ₃ SiOH, (C ₆ H ₁₃ ) ₃ S
_{iOH, (C 8 H 17)} 3 SiOH, (C 6 H 5) (CH 3) 2 SiOH, (C 6 H 5) 2 (CH 3) S
Examples thereof include iOH and (C ₆ H ₅ ) ₃ SiOH, but are not limited thereto.

The reaction between Q ₂ Sn═O and Q ₃ SiOH is carried out, for example, by placing a tin compound in a nitrogen-substituted four-necked flask, dropping the silanol compound in the presence of an organic solvent, and then adding 1 to 50 at 180 to 180 ° C. 1
It can be performed by stirring for 0 hours.

In addition to this, the reaction between Q ₂ Sn = 0 and Q ₃ SiOQ and Q ₂ SnY ₂ and Q ₃ SiZ
It can also be obtained by reaction with. Note that Q is the same group as described above, and Y and Z are groups selected from an alkoxy group, a halogen group, an acyloxy group, a hydroxyl group, and the like.

The amount of these curing catalysts used is 0.01 to 10 parts, preferably 0.1 to 8 parts, relative to 100 parts of the organic polymer (A), and the amount is 0.0
If it is less than 1 part, the pot life is long, but the curing is slow and not preferable, and if it exceeds 10 parts, physical properties such as heat resistance are adversely affected, which is not preferable.

The curable composition of the present invention can be widely used as a pressure-sensitive adhesive, an adhesive, a paint, a coating agent, a binder, a molded product such as a molding machine, an anti-vibration agent, a foam or a sealing material. Further, it can be used as a pressure-sensitive adhesive composition for tapes, sheets, labels, foils and the like. That is, for example, a solvent-free liquid type, a solvent type, an emulsion type or a hot melt type is applied to a substrate such as a film made of a synthetic resin or a modified natural product, paper, cloth, metal foil, metallized plastic foil, asbestos or glass fiber cloth. The adhesive composition may be applied in the form of, for example, exposed to moisture or water, and cured by heating.

When the composition of the present invention is used in a pressure-sensitive adhesive, it may be added in an amount of 40 to 120 based on 100 parts of the composition of the present invention in order to adjust the adhesive property.
You may add and use a tackifying resin in the range of. There is no particular limitation on the tackifying resin, for example, a resin having a polar group such as a rosin ester resin, a phenol resin, a xylene resin, a xylene phenol resin, a terpene phenol resin, an aromatic resin having a relatively small polarity, or an aliphatic-aromatic resin. Various petroleum resins such as a copolymer system or an alicyclic system, and a usual tackifying resin such as a coumarone resin, a low molecular weight polystyrene resin, and a sterpene resin may be used. Specific examples of these resins include Petrosin 80 (manufactured by Mitsui Petrochemical Co., Ltd.) and Neopolymer S (Japan Petrochemical Co., Ltd.).
), Tack Ace A100 (manufactured by Mitsui Petrochemical Co., Ltd.), Quinton 1500 (manufactured by Nippon Zeon Co., Ltd.), FTR6100 (manufactured by Mitsui Petrochemical Co., Ltd.), Picolastec A75 (manufactured by Hercules Co., Ltd.), Kumaron G- 90 (manufactured by Nittetsu Chemical Co., Ltd.) and other resins with relatively small polarity, YS Polystar T-115, YS Polystar S-145 (all manufactured by Yasuhara Yushi Co., Ltd.), Steberite Ester 7 (manufactured by Hercules Co., Ltd.) ), Neopolymer
Examples thereof include resins having a polar group such as E-100 (manufactured by Nippon Petrochemical Co., Ltd.), but are not limited thereto.

In addition to the above, the curable composition of the present invention may optionally contain a plasticizer, a filler, a reinforcing agent, an anti-sagging agent, a colorant, an antiaging agent, an adhesion promoter, a physical property modifier, and the like. Good.

As the plasticizer, depending on the purpose of adjusting physical properties, adjusting properties, etc., dibutyl phthalate, diheptyl phthalate,
Phthalates such as di (2-ethylhexyl) phthalate and butylbenzyl phthalate; non-aromatic dibasic acid esters such as dioctyl adipate and dioctyl sebacate; polyalkylene glycols such as diethylene glycol dibenzoate and triethylene glycol dibenzoate Esters; Phosphoric acid esters such as tricresyl phosphate and tributyl phosphate;
Chlorinated paraffins; hydrocarbon-based oils such as alkyldiphenyl and partially hydrogenated terphenyl may be used alone or in combination of two or more. Incidentally, these plasticizers may be blended at the time of polymer production.

As the filler and the reinforcing material, heavy and light calcium carbonates; calcium carbonate surface-treated with fatty acids, resin acids, cationic surfactants, anionic surfactants, etc .; magnesium carbonate; talc; titanium oxide; Ordinary materials such as barium sulfate; alumina; metal powders such as aluminum, zinc and iron; bentonite; kaolin clay; fumed silica; quartz powder; carbon black can be used, and these may be used alone, You may use 2 or more types together. Especially when fumed silica is used, it is possible to obtain a composition having excellent transparency.

Examples of the anti-sagging agent include hydrogenated castor oil derivatives; metal soaps such as calcium stearate, aluminum stearate, barium stearate, etc., but if necessary depending on the purpose of use or blending of fillers, reinforcing materials, etc. It may be used as appropriate.

As the colorant, a usual inorganic pigment, organic pigment, dye or the like may be used as required.

As the physical property adjusting agent, various silane coupling agents, for example, alkyltrioxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane and n-propyltrimethoxysilane; dimethyldiisopropenoxysilane, methyltriisopropeno Alkylisopropenoxysilanes such as xysilane, γ-glycidoxypropylmethyldiisopropenoxysilane; γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxylane, vinyltrimethoxysilane, vinyl Dimethylmethoxysilane, γ-aminopropyltrimethoxysilane, N- (β
-Aminoethyl) aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Alkoxysilanes having a functional group such as mercaptopropylmethyldimethoxysilane; silicone varnishes;
Polysiloxanes and the like are added as needed. By using these physical property adjusting agents, the hardness of the composition of the present invention when cured can be increased, or the hardness can be reduced to achieve elongation.

A solvent may be added to improve workability and reduce viscosity. Examples of the solvent used for this purpose include aromatic hydrocarbon solvents such as toluene and xylene;
Examples thereof include ester solvents such as ethyl acetate, butyl acetate, amyl acetate and cellosolve acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone.

Hereinafter, the curable composition of the present invention will be described in more detail with reference to examples.

Synthesis Example 1 Polypropylene oxide having an average molecular weight of 8,000 and having an allyl ether group at a ratio of 98% among all terminals (manufactured from polypropylene glycol as a starting material) 80
0 g was placed in a pressure resistant reactor equipped with a stirrer, 20 g of methyldimethoxysilane was added, and subsequently, a solvent solution of chloroplatinic acid (H ₂ PtCl ₆
-0.34 ml of a solution prepared by dissolving 8.9 g of 6H ₂ O in 18 ml of isopropyl alcohol and 160 ml of tetrohydrofuran) was added, and the mixture was reacted at 80 ° C for 6 hours.

The amount of unreacted silane was determined by gas chromatography and infrared analysis to determine the reaction rate.
84% are responding, A polypropylene oxide having a terminal was obtained.

Synthesis Example 2 24.9 g of Bu ₂ SnO was added to a 300 ml four-neck flask with nitrogen substitution.
(0.1 mol) and toluene 24.9g were put and stirred. Me ₃ SiOH (9.0g (0.1mol)) was added dropwise to this slurry at 100 ℃.
When heated and stirred in the oil bath for 3 hours, the slurry completely disappeared and a uniform transparent solution was obtained. After removing the water generated by passing through a filter paper, the solvent was removed to give a white solid. I got it.

Synthesis Example 3 A white solid was prepared in the same manner as in Synthesis Example 2 except that 21.4 g (0.1 mol) of Ph ₂ MeSiOH was used instead of Me ₃ SiOH. I got it.

Synthetic Example 4 Me ₃ SiOH is twice as much as that of Synthetic Example 2 and is 18.0 g (0.2 mol).
l) A white solid of Bu ₂ was prepared in the same manner as in Synthesis Example 2 except that it was used.
Sn (OSiMe ₃ ) ₂ was obtained.

Synthesis Example 5 n-Butyl acrylate 128 g (1.0 mol), γ-methacryloxypropylmethyldimethoxysilane 3.48 g (0.015 mol)
l), γ-mercaptopropylmethyldimethoxysilane 2.
46 g (0.015 mol) and 0.25 g of α, α'-isobisisobutyronitrile were mixed and dissolved. 30 g of this mixed solution was placed in a 300 ml four-necked flask purged with nitrogen gas, placed in an oil bath at 70 ° C. and gradually heated with stirring. Polymerization soon started, and heat generation and thickening phenomenon were observed, but the remaining mixed solution was gradually added dropwise from a dropping funnel over 2.5 hours while continuing stirring. After completion of the dropping, the mixture was stirred for 1 hour as it was to complete the polymerization, and a colorless and transparent viscous substance having a polymerization rate of 97% and a viscosity of 350 P (23 ° C.) was obtained.

Examples 1 to 3 and Comparative Examples 1 to 3 Silyl-terminated polypropylene oxide 100 obtained in Synthesis Example 1
Terpene phenolic resin (YS Polystar T-115 manufactured by Yasuhara Yushi Co., Ltd.) with a softening point of 115 ° C as a tackifying resin.
A mixed solution of 0 parts and 53 parts of toluene was added to make a uniform solution. To this, 5 parts of the curing catalyst shown in Table 1 was added and uniformly mixed.

The obtained solution was applied onto a polyester film (thickness: 25μ) so that the paste thickness after drying was 25μ, and heat-treated in a heater to determine the temperature and time required for curing. Again 1
Heat treatment was carried out at 120 ° C. for 5 minutes, and the adhesive property was measured after standing at room temperature for 5 days.

On the other hand, the rest of the solution was left at room temperature (about 20 ° C.) to determine the pot life. The results are shown in Table 1.

(Curability) A pressure-sensitive adhesive sheet heat-treated at a predetermined temperature for a predetermined time is immediately attached to a stainless steel plate, and at the same time, 180 ° peeling is performed. When the curing is sufficiently advanced, the cohesive force is developed, and there is no adhesive residue, it is evaluated as ○, when the curing is insufficient and adhesive peels off on the entire surface, it is evaluated as ×, and the intermediate state is evaluated as Δ.

(Pot life) Measure the time until the coating cannot be applied due to thickening after leaving it at room temperature (about 20 ° C).

(Adhesive physical properties) (i) Tack: Measured by the J. Dow method inclined ball tack method.

(ii) Adhesive strength: An adhesive sheet was attached to a stainless steel plate, and after 60 minutes, 180 ° peel strength was measured at 23 ° C at a speed of 300 mm / min.

(iii) Holding power: Stick an adhesive sheet on a stainless steel plate with an area of 25 mm × 25 mm, and put a 1 kg weight on the edge of the adhesive sheet at 80 ° C.
Suspend for 60 minutes and measure the displaced distance of the adhesive sheet.

Example 4 and Comparative Examples 4 to 5 To 100 parts of the silyl group-containing acrylic polymer obtained in Synthesis Example 5, 10 parts of toluene was added to prepare a uniform solution. Synthesis example 2
3 parts of the compound obtained above was added and mixed uniformly. This solution was applied onto a polyester film (thickness: 25μ) so that the paste thickness after drying would be 25μ, and heat-treated in a heating machine, which cured at 90 ° C for 1 minute to give a rubber elastic body. . The pot life measured in the same manner as in Examples 1 to 3 was 8 hours.

As a comparative example, when 3 parts of Bu ₂ Sn (laurate) ₂ was used as a curing catalyst, it was heated at 120 ° C. for 3 minutes to finally obtain a rubber elastic body. In addition, as a comparative example, Bu was used as a curing catalyst.
_When 3 parts of ₂ Sn (OMe) ₂ was used, a rubber elastic body was obtained at 90 ° C. for 1 minute, but the pot life was 30 minutes.

[Effects of the Invention] The curable composition of the present invention cures rapidly at high temperatures, has a sufficiently long pot life, and has good workability when used as a pressure-sensitive adhesive (pressure-sensitive adhesive), and has good adhesive properties. Is also good.

Claims (4)

[Claims] 1. A polymer having at least one reactive silicon-containing group in the molecule and having essentially the following general formula as a main chain: —R ¹ —O—.
(Wherein R ¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms), or an alkylene oxide polymer having a repeating unit represented by the formula or at least one reactive silicon-containing group in the molecule. With respect to 100 parts by weight of an organic polymer (A) made of an acrylic polymer, a general formula as a curing catalyst (B): (Wherein, Q is a group selected from monovalent hydrocarbon groups having 1 to 20 carbon atoms, and each Q may be the same or different). A curable composition comprising 10 parts by weight. 2. The curable composition according to claim 1, wherein the organic polymer (A) has a reactive silicon-containing group at the end of the molecule and has a molecular weight of 3000 to 15000. 3. The curable composition according to claim 1, wherein the reactive silicon-containing group is an alkoxysilyl group. 4. The curing catalyst (B) is Bu ₂ Sn (OSiMe).
₃ ) ₂ or The curable composition according to claim 1, which is