JP3221926B2 - Curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel curable composition. More specifically, the present invention relates to a composition which is excellent in curability and gives a cured product having excellent surface appearance (presence or absence of bleed) and excellent mechanical strength.

[0002]

2. Description of the Related Art Examples of organic polymers which can be crosslinked by a silanol condensation reaction include polyalkylene oxides having reactive silicon groups. Polyalkylene oxide having a reactive silicon group (JP-B-45
No. -36319) is a polymer, such as a room-temperature-curable silicone rubber, which is cured even at room temperature by moisture in the air to give a rubber-like material. Since this cured product has excellent flexibility, elongation characteristics, transparency, and adhesion to an adherend, it is used for applications such as sealants and adhesives.

[0003] Such an organic polymer having a reactive silicon group requires a curing catalyst in order to promote crosslinking. As the curing catalyst, a generally used silanol condensation catalyst, for example, a known silanol catalyst such as an organometallic compound or an acid-base compound is used. However, since such a relatively low molecular weight catalyst is used, the curing catalyst bleeds on the surface of the cured product over a long period of time or at a high temperature to impair the appearance of the surface, or the mechanical strength may be insufficient depending on the application. there were. Such disadvantages can be improved by reducing the amount of the curing catalyst used, but the curability becomes insufficient, the gel content of the cured product does not increase, and the shape retention of the cured product is not sufficient, and with a small force. There were problems such as deformation of the cured product.
That is, it has been a problem to achieve both curability, surface appearance, and mechanical strength.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a composition which gives a cured product having excellent curability, excellent surface appearance, and excellent mechanical strength, in that the gel content in the cured product is small.

That is, the present invention provides an organic polymer which can be crosslinked by a silanol condensation reaction, and (A) an amine compound having at least one polymerizable double bond in a molecule;
And / or (B) a curable composition containing a curing catalyst comprising an acidic phosphate having at least one polymerizable double bond in the molecule. An organic polymer composition which can be crosslinked by a silanol condensation reaction using an amine compound and / or an acidic phosphoric acid ester as a curing catalyst is disclosed in JP-A-3-122175. Those having a heavy bond are not specifically disclosed.

The term "organic polymer which can be crosslinked by a silanol condensation reaction" as used in the present invention refers to an organic polymer which is condensed to form a siloxane bond and changes into a resin or rubber state, and is a rubber-based organic polymer. Is preferred. Further, the rubber organic polymer referred to in the present invention becomes a rubbery state after curing, and has flexibility. In addition, having the flexibility referred to in this specification means that
Of course, it can be bent with very little finger force at room temperature, but the longitudinal elastic modulus at room temperature is 5 × 10 ⁷ dyn / cm ² (About 50 k
g / cm ² ) Means:

As such a specific rubber-based organic polymer, for example, a rubber-based organic polymer having at least one reactive silicon group in a molecule and being liquid at room temperature (hereinafter referred to as a rubber-based organic polymer (a)) And the like).

[0008] The main chain of this specific rubber-based organic polymer is not particularly limited as long as the cured product is an organic polymer that becomes a rubber-like material. The reactive silicon group contained in the rubber-based organic polymer (a) is a well-known group, and has a feature that it can be crosslinked at room temperature.

The reactive silicon group is a silicon-containing group which has a hydroxyl group or a hydrolyzable group bonded to a silicon atom and can be cross-linked by forming a siloxane bond. Is a group represented by the following general formula. ^{_{X a (R 1 3-a}} ) Si - [- O-Si (X b) (R 1 2-b) -] m -

In the formula, X is a hydroxyl group or a hydrolyzable group, and R ¹ Is a monovalent hydrocarbon group or a triorganosiloxy group having 1 to 20 carbon atoms, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, and m is 0 or 1. ~ 19
Where 1 ≦ a + mb.

Specific examples of the hydrolyzable group include, for example, generally known groups such as a hydrogen atom, a halogen atom, an alkoxy group and an acyloxy group. Among these, the alkoxy group is mildly hydrolyzable,
It is particularly preferable because it is easy to handle.

R ¹ Specific examples include an alkyl group such as a methyl group and an ethyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, an aralkyl group such as a benzyl group, and a trimethylsiloxy group. Further, it may be a hydrocarbon group in which some hydrogen atoms are substituted. Of these, a methyl group is particularly preferred.

One molecule of the rubber organic polymer (a) contains at least one, preferably 1.2 to 6 reactive silicon groups. If the number of reactive silicon groups contained in one molecule is less than one, curing becomes insufficient, which is not preferable. On the other hand, when the number exceeds 6, the flexibility of the cured product becomes insufficient.

In the rubber-based organic polymer (a), the reactive silicon group is preferably present at a molecular terminal. When a reactive silicon group is present at the molecular end, the molecular weight between cross-linking points becomes large, so that there is an advantage that a cured product having flexibility and high elongation can be easily obtained.

The main chain of the organic polymer which can be crosslinked by the silanol condensation reaction used in the present invention includes, for example, polyethers obtained by polymerization of cyclic ethers such as propylene oxide, ethylene oxide and tetrahydrofuran; Polyester obtained by condensation of dibasic acid and glycol or ring-opening polymerization of lactones; ethylene-propylene copolymer; polyisobutylene, or copolymer of isobutylene and isoprene; polychloroprene; polyisoprene or isoprene Copolymers of butadiene, styrene, acrylonitrile, etc .; polybutadienes, or copolymers of butadiene and styrene, acrylonitrile, etc .; Olefins; polyacrylates obtained by radical polymerization of monomers such as ethyl acrylate and butyl acrylate, or copolymers of the acrylates with vinyl acetate, acrylonitrile, styrene, ethylene, etc .; Graft polymer systems obtained by polymerizing vinyl monomers in the coalescence; polysulfide-based polymers and the like.
Among them, a general formula of a polypropylene oxide-based polyether or the like: -R-0- [where R represents a carbon number of 2 to 4;
And a graft obtained by polymerizing a vinyl monomer such as acrylate, styrene, acrylonitrile, or vinyl acetate in the presence of a polyether having a repeating unit represented by the formula: A polymer or copolymer such as a polymer, a polyacrylate alkyl ester, or a copolymer of an alkyl acrylate containing 50% or more of an alkyl acrylate and a copolymer of vinyl acetate, acrylonitrile, styrene, ethylene, or the like is reacted. It is preferable in terms of easy introduction of a reactive silicon group into a molecular terminal and easy production of a liquid polymer without a solvent. Polypropylene oxide is particularly preferred because it has good water resistance, is inexpensive, and is easy to handle as a liquid.

The molecular weight of the rubber-based organic polymer is about 500 to 50,000, especially 1000 to 2,000, because the rubber-based organic polymer needs to be in a liquid state at room temperature.
About 0 is preferable.

The curing catalyst used together with the organic polymer acts on the organic polymer to crosslink and cure, thereby producing a cured product. In addition, the polymer itself polymerizes to a high molecular weight. Such a curing catalyst includes an amine compound (A) having at least one polymerizable double bond in a molecule and / or an acidic phosphate having at least one polymerizable double bond in a molecule. There is no particular limitation as long as it is a curing catalyst composed of (B).

Specific examples of the amine compound (A) which is a component of the curing catalyst of the present invention include, for example, amine compound esters of α, β-unsaturated carboxylic acids, N-vinylamine compounds, aminoalkyl vinyl ethers, Aminoalkyl vinyl ketone and the like.

Specific examples of the amine compound ester of the α, β-unsaturated carboxylic acid include, for example, 2-aminoethyl acrylate, 2-N, N-dibutylaminoethyl acrylate, 2-N, N-dimethylaminoethyl Methacrylate, 2-
N, N-diethylaminoethyl methacrylate, 3-Nt-octylaminopropyl methacrylate and the like can be mentioned. Specific examples of the N-vinylamine compound, for example, N-
Vinyldimethylamine, N-vinylethylbutylamine,
N-vinyldiphenylamine and the like can be mentioned.

Specific examples of the aminoalkyl vinyl ether include, for example, 2-aminoethyl vinyl ether,
2-N, N-dimethylaminoethyl vinyl ether and the like. Specific examples of the aminoalkyl vinyl ketone include, for example, 2-aminoethyl vinyl ketone, 2-N, N-dimethylaminoethyl vinyl ketone, and the like. Also,
Specific examples of the acidic phosphate (B) include, for example, compounds represented by the following general formula. CH ₂ ＣC (R ² ) COOR ³ OP (= O) (OH) (OR ⁴ ) CH ₂ ＣC (R ² ) OR ³ OP (= O) (OH) (OR ⁴ ) CH ₂ ＣC (R ² ) R ³ OP (= O) (OH) (OR ⁴ ) CH ₂ ＣC (R ² ) OP (= O) (OH) (OR ⁴ Wherein R ² Is hydrogen or methyl, R ³ Represents 1 to 1 carbon atoms
20 divalent hydrocarbon groups, R ⁴ Is hydrogen or 1 carbon atom
And represents a monovalent hydrocarbon group of -20. The general formula CH ₂ C (R ² ) COOR ³ OP (= O) (OH) (OR ⁴ )

Specific examples of the compound represented by the following are mono (2-acryloyloxyethyl) acid phosphate,
Mono (2-methacryloyloxyethyl) acid phosphate, methyl-2-methacryloyloxyethyl acid phosphate, lauryl-2-acryloyloxyethyl acid phosphate and the like can be mentioned. The general formula CH ₂ C (R ² ) OR ³ OP (= O) (OH) (OR ⁴ )

Specific examples of the compound represented by the formula (1) include mono (2-vinyloxyethyl) acid phosphate and methyl-2-vinyloxyethyl acid phosphate. The general formula CH ₂ C (R ² ) R ³ OP (= O) (OH) (OR ⁴ Specific examples of the compound represented by (1) include monoallyl acid phosphate and methylallyl acid phosphate. The general formula CH ₂ C (R ² ) OP (= O) (OH) (OR ⁴ Specific examples of the compound represented by (1) include monovinyl acid phosphate and methyl vinyl acid phosphate. Of these, amine compound esters of α, β-unsaturated carboxylic acids and the general formula CH ₂ ＣC (R ² ) COOR ³ OP (= O) (OH) (OR ⁴ Wherein R ² Is hydrogen or methyl, R ³ Is 1 carbon atom
~ 20 divalent hydrocarbon groups, R ⁴ Represents hydrogen or a monovalent hydrocarbon group having 1 to 20 carbon atoms.]

The neutralized reaction product with the acidic phosphoric acid ester represented by the formula (1) has excellent storage stability and handling workability of the curing catalyst,
It is preferable from the viewpoint that the curability of the curable composition, the pot life, and the heat resistance of the obtained cured product are good.

The curing catalyst is used in an amount of 0.1 to 20 parts by weight, and more preferably 100 to 100 parts by weight of the rubber organic polymer.
It is preferably 10 parts by weight. If the amount is less than 0.1 part by weight, the curability of the base material is not sufficient, and if it exceeds 20 parts by weight, the curing is too fast and the workability deteriorates.

In some cases, the curing catalyst itself can be polymerized by thermal polymerization or the like under the curing conditions of an organic polymer, but a polymerization initiator can be used. The polymerization initiator is not particularly limited, and a commonly used polymerization initiator can be used.

The composition of the present invention is useful as a sealant, an adhesive, a pressure-sensitive adhesive, a coating waterproofing agent, a packaging material, a cast rubber material, and a molding material. Depending on these uses, various additives such as a filler used for adjusting the physical properties of the cured product and a solvent for adjusting the viscosity of the composition can be added to the composition of the present invention.

Specific examples of the filler include, for example,
Examples include fine silica powder, calcium carbonate, clay, talc, titanium oxide, zinc white, diatomaceous earth, barium sulfate, carbon black, and fine hollow spheres.

Examples of the inorganic micro-spherical hollow body include a glass spherical micro-hollow body, silica balloon, fly ash balloon, shirasu balloon and the like. Examples of the organic microspherical hollow body include a phenol resin. These may be used alone or in combination of two or more. Further, those obtained by treating the surfaces of these spherical minute hollow bodies with a silane compound, polypropylene glycol or the like can also be used. These minute hollow bodies are used to reduce the weight of the cured product without impairing the flexibility, elongation and mechanical strength of the cured product. Also, antioxidants, ultraviolet absorbers,
Pigments, surfactants, tackifying resins and the like are used according to the respective purposes, but are not limited thereto.

Specific examples of the tackifier resin include, for example,
Examples include phenol resins, modified phenol resins, terpene-phenol resins, petroleum resins, rosin ester resins, low molecular weight polystyrene resins, terpene resins, and the like. These may be used alone or in combination of two or more. Among these, phenol resin-based and phenol-containing resin-based resins are particularly preferred because they easily exhibit flexibility, high elongation and high strength. The amount of the tackifier resin used is preferably 0 to 140 parts by weight, more preferably 5 to 80 parts by weight, based on 100 parts by weight of the organic polymer. The composition of the present invention to which the tackifier resin is added can be effectively used as a curable composition for a pressure-sensitive adhesive, particularly as a curable composition for a substrate of a pressure-sensitive adhesive, and the flexibility of the substrate can be improved. It is effective to adjust and increase the strength.

Further, various silane coupling agents may be added in appropriate amounts for the purpose of improving the adhesion to the adherend.
Examples of the silane coupling agent used include an amino group, an epoxy group, an acryl group, a methacryl group, a mercapto group,
A silane coupling agent having a functional group such as a vinyl group can be exemplified. The addition of an appropriate amount of silicone varnish also has the effect of improving the adhesion to the adherend.

In the present invention, the mixing of the rubber-based organic polymer with other components may be carried out using a mixer such as a Banbury mixer, a kneader, a roll, or a planetary mixer, of which a tackifying resin is used. In this case, the powder can be easily mixed by previously pulverizing the powder into a fine powder of about 1 to 100 μm. The fine powder of the tackifier resin does not necessarily have to be in a homogeneously dissolved state before coating, and may be present in the rubber-based organic polymer in a non-uniformly dispersed state as small particles.

Since the curing catalyst used in the present invention is a liquid at room temperature during mixing, it is easily dispersed or dissolved in the composition, so that the curability does not decrease. In addition, the curing catalyst itself polymerizes and polymerizes at the time of heat curing, so that the mechanical strength is not reduced, and the surface appearance is not impaired since it does not bleed.

[0033]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Examples 1 and 2 per molecule average of 1.5 amino dimethoxy silyl _{group: -Si (CH 3) (OCH} 3) 2

A polymer comprising propylene oxide having an average molecular weight of 7,500 (hereinafter referred to as a propylene oxide polymer), a hindered phenolic antioxidant (Nocrack NS-6, manufactured by Ouchi Shinko Chemical Co., Ltd.), ultraviolet light An absorbent (Tinuvin 327, manufactured by Ciba-Geigy) was weighed in a predetermined amount as shown in Table 1, and kneaded and mixed four times with three paint rolls. Then, Shirasu balloon (Windite MSB5011 manufactured by Ichi Kasei Co., Ltd.) and 2-N, N-dimethylaminoethyl methacrylate (Kyoeisha Yushi Kagaku Kogyo Co., Ltd .: Light Ester DM) as a curing catalyst and mono (2-
A predetermined amount of an equal mixture with (methacryloyloxyethyl) acid phosphate (light ester PM, manufactured by Kyoeisha Yushi Kagaku Kogyo KK) was added and mixed, followed by defoaming under reduced pressure. Using a doctor blade, the obtained curable composition was treated with a silicon peeling PET film (manufactured by Toyo Metallizing Co., Ltd.):
After coating on the therapeutic Q-1) to a thickness of 1.1 mm, a heat-curing treatment was performed at 140 ° C. for 20 minutes to obtain a cured sheet. The obtained cured product was immersed in acetone for 48 hours at room temperature immediately after curing and after treatment at 65 ° C., and the curability was evaluated by measuring the gel content.

Furthermore, tensile properties after curing at 65 ° C. for 7 days (Dumbbell JIS No. 3, tensile speed 300 mm / min, measurement temperature 2
(3 ° C., using an autograph) was measured to evaluate mechanical strength (tensile strength), flexibility (M ₁₀₀ : tensile stress at 100% elongation), and elongation characteristics. Further, the surface appearance was visually evaluated from the presence or absence of bleed on the surface of the cured product. The results are as shown in Table 1. Example 3

In Example 1, a straight novolak phenol resin (Sumitomo Durez Co., Ltd.) was used as the tackifying resin.
Production: PR-50731) was carried out in the same manner as in Example 1 except that 20 parts by weight of a fine powder (average particle size: 15 μm) was further added. Table 1 shows the measurement results of the same items as in Example 1. Example 4

The procedure was performed in the same manner as in Example 1 except that a shirasu balloon (Winlite MSB5011 manufactured by Ichi Kasei Co., Ltd.) was not used. Table 1 shows the measurement results of the same items as in Example 1. Comparative Examples 1 and 2

The curing catalyst blended in Examples 1 and 2 was replaced with lauryl dimethylamine (Pharmin DM-2 manufactured by Kao Corporation).
0) and dibutyl phosphate (DP-4, manufactured by Daihachi Chemical Industry Co., Ltd .: DP-4), except that the mixture was replaced with an equal amount. Table 1 shows the measurement results of the same items as in Example 1.

[0039]

[Table 1]

In consideration of the above results, as shown in the results of Comparative Examples 1 and 2, when a non-polymerizable curing catalyst was used, the gel content of the cured product did not increase when the amount used was small. If the amount is too large, the gel content increases but the surface appearance deteriorates. In contrast, it is clear that the composition of the present invention increases the gel content and does not deteriorate the surface appearance even when the amount of the curing catalyst used is small.

[0041]

The curable composition of the present invention not only has excellent curability, but also has excellent surface appearance (presence or absence of bleed) and mechanical strength of the obtained cured product.

Claims (1)

(57) [Claims] 1. An organic polymer which can be crosslinked by a silanol condensation reaction; (A) an amine compound having at least one polymerizable double bond in a molecule; and (B) at least one polymer in a molecule. A curable composition comprising a curing catalyst comprising an acidic phosphate ester having a possible double bond.