JP2723269B2 - Curable composition - Google Patents

Description

The present invention has a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom, and has a silicon-containing group capable of crosslinking by forming a siloxane bond. The present invention relates to a curable composition containing an oxyalkylene-based polymer and giving a cured product that is lightweight and has excellent strength.

[Problems to be Solved by the Related Art] A silicon-containing group having a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom and capable of being crosslinked by forming a siloxane bond (hereinafter referred to as reactive silicon) Oxyalkylene-based polymer having a carboxylic acid group) is disclosed in JP-A-52-739.
No. 98 and the like, and a typical example thereof is a general formula: (Wherein X 'is a hydrolyzable group such as a methoxy group).

The oxyalkylene polymer having a reactive silicon group is a siloxane bond (Si-O-Si) between the polymers due to the action of moisture in the air at room temperature, such as a room-temperature-curable silicone rubber.
To give a rubbery cured product. The cured product has excellent tensile properties such as high elongation, low modulus, and high breaking strength, excellent adhesiveness, good paintability, and is used for sealants and adhesives.

However, weight reduction is required for some applications such as automotive sealants.

In order to achieve the purpose of reducing the weight of the cured product, studies have been made on a foamed cured product. However, in this case, although the purpose of weight reduction can be achieved, a new problem arises such that only a cured product having low strength is obtained.

[Means for Solving the Problems] The present invention does not substantially reduce the strength and the like of the cured product,
(A) a hydroxyl group bonded to a silicon atom and / or
100 parts (parts by weight, hereinafter the same) of an oxyalkylene polymer having a hydrolyzable group and having at least one silicon-containing group which can be crosslinked by forming a siloxane bond; and (B) 1 to 20 parts of a glass balloon A curable composition comprising:

[Examples] Oxyalkylene polymers having at least one reactive silicon group (hereinafter referred to as oxyalkylene polymers (A)) used in the present invention are described in JP-B-45-36319 and JP-B-46-1.
No. 2154, No. 49-32673, JP-A-50-156599, No. 51-7356
No. 1, 54-6096, 55-83123, 55-123620, 5
5-125121, 55-131022, 55-135135, 55-137
It is a polymer proposed in each publication of No. 129.

The molecular chain of the oxyalkylene polymer (A) has a general formula: -R ¹ -O- (wherein R ¹ is a substituted or unsubstituted divalent hydrocarbon group having 1 to 12 carbon atoms). Having a repeating unit represented by The main chain of the oxyalkylene polymer has a general formula: -R ¹
It may consist of only the repeating unit represented by -O-, but may contain other repeating units and the like. When the compound contains other repeating units, the general formula: -R ¹ -O-
The repeating unit represented by is preferably at least 60% (% by weight, hereinafter the same), more preferably at least 80% of the polymer.

R ¹ is a substituted or unsubstituted 2 to 5 carbon atoms.
Preferred are aliphatic hydrocarbon groups of value, especially aliphatic hydrocarbon groups of 3 to 4 carbon atoms. Specific examples of R ¹ include -C
_{H (CH 3) CH 2 -} , - CH (C 2 5) CH 2 -, - C (CH 3) 2 CH
_2- , -CH ₂ CH ₂ CH ₂ CH _2-, etc.
C (CH ₃₎ CH ₂ - it is preferred. The molecular chain of the oxyalkylene polymer (A) may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units.

The reactive silicon group in the oxyalkylene polymer (A) is a well-known functional group, and has a feature that it can be crosslinked at room temperature. A typical example of the reactive silicon group is represented by the general formula (I): (Wherein R ² is a monovalent organic group having 1 to 40 carbon atoms and R ² is 2
R ² may be different when two or more are present, X is a hydroxyl group or a hydrolyzable group, X is different when two or more are present, a is 0, 1 or 2, b
Is 0, 1, 2 or 3, and b + (sum of a) ≧
1, m is an integer of 0 to 19, and when m is 2 or more, A need not be the same). Among the reactive silicon groups represented by the general formula (I), the general formula (II): (Wherein R ² is the same as above, and l is 1, 2 or 3).

Specific examples of the hydrolyzable group that is one kind of X in the general formula (I) include a halogen atom, a hydrogen atom, an alkoxy group, an acyloxy group, a ketoxime group, an amino group, an amide group, an aminooxy group, a mercapto group, An alkenyloxy group and the like can be mentioned. Among these, an alkoxy group such as a methoxy group and an ethoxy group is preferred from the viewpoint of mild hydrolysis.

R ² in the general formula (I) has 1 to 4 carbon atoms.
Zero-substituted or unsubstituted hydrocarbon groups and triorganosiloxy groups can be exemplified. Typical examples of R ² include general formulas such as 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. A triorganosiloxy group represented by (R ') ₃ SiO- (wherein R' is a monovalent organic group having 1 to 20 carbon atoms and three R's need not be the same). Can be Of these, a methyl group is particularly preferred.

The number of reactive silicon groups in the oxyalkylene polymer (A) may be one or more, but from the viewpoint of obtaining sufficient curability, the number is preferably 1.1 or more, and more preferably 1.5 to 4 on average. Further, the reactive silicon group is preferably present at the terminal of the molecular chain of the oxyalkylene polymer (A).

The number average molecular weight of the oxyalkylene polymer (A) is 3,
000 to 30,000 are preferred, and 5,000 to 15,000 are more preferred. The oxyalkylene polymer (A) may be used alone or in combination of two or more.

The oxyalkylene polymer (A) can be produced by various methods. As an example of such a method, an oxyalkylene polymer having a certain functional group (referred to as a Y group) is reacted with a functional group capable of reacting a Y group (referred to as a Y ′ group) and a compound having a reactive silicon group. And introducing a reactive silicon group into the oxyalkylene polymer.

Specific examples of such a method include an oxyalkylene polymer having an unsaturated group and HSi.
Method of reacting (hydrosilylation) a hydrosilane compound having a hydrolyzable group such as (OCH ₃ ) ₃ with a group VIII transition metal compound or the like as a catalyst (reaction example) Oxyalkylene polymers having unsaturated groups and HS
Method for performing an addition reaction between a compound having a mercapto group and a reactive silicon group such as (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , and an oxyalkylene polymer having an isocyanate group and H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) Method of reacting a compound having an active hydrogen group and a reactive silicon group such as ₃ (reaction example) Oxyalkylene polymer having hydroxyl group and OCN (C
A method of reacting a compound having an isocyanate group and a reactive silicon group, such as H ₂ ) ₃ Si (OCH ₃ ) ₃ , may be used. Among these methods, a method of reacting an oxyalkylene polymer having an unsaturated group with a hydrosilane compound is often used. An oxyalkylene polymer having an unsaturated group is, for example, a method of introducing an unsaturated group using a hydroxyl group of an oxyalkylene polymer having a hydroxyl group as disclosed in JP-A-54-6097. Can be obtained by:

The oxyalkylene-based polymer (A) used in the present invention is not limited to those obtained by the above method, and any polymer obtained by any other method can be used. Further, a polymer obtained by polymerizing a polymerizable monomer such as a vinyl monomer in the presence of the oxyalkylene polymer (A), or a polymerizable monomer in the presence of an oxyalkylene polymer having a hydroxyl group. The oxyalkylene-based polymer (A) of the present invention also includes a polymer in which a polymer chain or the like is modified, such as a polymer obtained by polymerizing a monomer and further introducing a reactive silicon group into the polymer obtained. Polymer.

The composition of the present invention contains a glass balloon as a component for reducing the weight of the cured product without reducing the strength of the cured product.

The glass balloon is a substantially hollow glass micro hollow sphere obtained by foaming fine artificial glass.

The type of artificial glass constituting the glass balloon is not particularly limited, for example, borosilicate glass,
Artificial glass such as borosilicate glass can be used.

The average particle size of the glass balloon, the average particle density and the like are not particularly limited, and may be used as long as they are in the range called a glass balloon.
About 200 μm, preferably about 30 to 100 μm, average particle density about 0.1 to 0.6 g / cc, preferably about 0.15 to 0.3 g / cc,
Bulk density 0.05 to 0.5 g / cc, preferably about about 0.07~0.3g / cc, compression strength 10~1000kg / cm ^2, preferably about 15~300k
Those having a g / cm ^{2 of} about 90% or more in bulk capacity are generally used.

There is no particular limitation on the shape of the glass balloon,
Those close to a true sphere are preferred from the viewpoint of little increase in viscosity.

As a specific example of the glass balloon, for example, a general-purpose series glass bubbles having both low density, high strength, and chemical resistance, which is commercially available from Sumitomo 3M under the trademark “Scotchlite” (for example, bubble) type
C 15/250, B 23/500, B 28/750, B 37/2000, B 38/400
0, B 46/4000, S 60/10000, E 22/400) and Floated series glass bubbles (for example, Hubble type A 16 / 500, A 20/1000, D 32/4500), an inorganic hollow sphere silica balloon having a low density characteristic and commercially available from Asahi Glass under the trademark "Q-CEL" (for example, Q-CEL). CEL 200, Q-CEL 30
0) and the like.

The amount of the glass balloon used is generally 1 to 20 parts, preferably 2 to 1 part, per 100 parts of the oxyalkylene polymer (A).
Although it is about 5 parts, in terms of volume ratio, the glass balloon is preferably about 5 to 100% with respect to the oxyalkylene polymer (A) from the viewpoint of mechanical properties, specific gravity and cost.

The composition of the present invention may be used by adding a curing accelerator, a plasticizer, a filler, and other additives as necessary.

Examples of the curing accelerator that can be used in the present invention include organic tin compounds, acidic phosphate esters, reactants of acidic phosphate esters with amines, saturated or unsaturated polycarboxylic acids or acid anhydrides thereof, and organic titanates. And the like.

Specific examples of the organotin compound include dibutyltin dilaurate, dioctyltin maleate, dibutyltin phthalate, tin octylate, dibutyltin dimethoxide, and the like.

In addition, the acidic phosphate ester, Phosphate ester containing moieties, such as (Wherein d is 1 or 2, and R ⁴ represents an organic group). And so on.

Examples of the organic titanate compound include titanates such as tetrabutyl titanate, tetraisopropyl titanate, and triethanolamine titanate.

When a curing accelerator is used, it is preferably used in an amount of 0.1 to 10 parts based on 100 parts of the oxyalkylene polymer (A).

As a plasticizer that can be used in the present invention, a low-molecular plasticizer,
Either a high-molecular plasticizer or a high-viscosity plasticizer can be used.

Specific examples of the plasticizer include phthalic acid esters such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, di (2-ethylhexyl) phthalate, butyl benzyl phthalate, and butyl phthalyl butyl glycolate; dioctyl adipate, dioctyl seba Non-aromatic dibasic acid esters such as keto;
Esters of polyalkylene glycols such as diethylene glycol dibenzoate and triethylene glycol benzoate; phosphoric esters such as tricrenylene phosphate and tributyl phosphate; paraffin chlorides; and hydrocarbon oils such as alkyl diphenyl and partially hydrogenated terphenyl. can give. These may be used alone or in combination of two or more. In addition, you may mix | blend these plasticizers at the time of polymer production.

When a plasticizer is used, it is preferably used in an amount of 1 to 150 parts, more preferably 10 to 20 parts, and particularly preferably 20 to 100 parts, per 100 parts of the oxyalkylene polymer (A).

Examples of the filler include heavy calcium carbonate,
Light calcium carbonate, colloidal calcium carbonate, kaolin,
Examples include talc, silica (non-hollow), titanium oxide, aluminum silicate, magnesium oxide, zinc oxide, and carbon black.

When the above filler is used, it is preferable to use the filler in an amount of 10 to 300 parts based on 100 parts of the oxyalkylene polymer (A).

Examples of the other additives include anti-sagging agents such as hydrogenated castor oil and organic benzonites, coloring agents, anti-aging agents, and adhesion-imparting agents.

 Next, a method for preparing the composition of the present invention will be described.

When mixing the glass balloon, it can be handled in the same manner as other inorganic fillers, except that it is necessary to take care not to break the balloon due to the shearing force at the time of mixing.

The composition of the present invention thus obtained comprises an adhesive,
It can be usefully used as an adhesive, a paint, a coating inhibitor, a sealing material composition, a molding material, a cast rubber material, and the like, and a light-weight, high-strength cured product can be obtained. Further, in some cases, the price per volume is reduced.

For example, when applied as a building sealant,
In general, 50 to 150 parts of an inorganic filler such as calcium carbonate, talc, and kaolin are added to 100 parts of the composition of the present invention, and if necessary, a pigment such as titanium oxide and carbon black, an ultraviolet absorber, a radical chain inhibitor, and the like. After adding an appropriate amount of the anti-aging agent, the mixture is kneaded sufficiently uniformly, and the mixture is cured by exposing it to moisture in the air to obtain a rubber elastic body having good properties. The rubber elastic body obtained in this way is excellent in mechanical strength although it is 96-80% lighter than the conventional rubber elastic body.

Next, the composition of the present invention will be specifically described based on examples.

Synthesis Example 1 800 g of a polyoxypropylene polymer having an average molecular weight of about 8000 in which an allyl ether group was introduced into 97% of all terminals was placed in a pressure-resistant reaction vessel equipped with a stirrer, and 19 g of methyldimethoxysilane was added. Then chloroplatinic acid catalyst solution _{(H 2 PtCl 6 · 6H 2} O in
8.9 g was dissolved in 18 ml of isopropyl alcohol and 160 ml of tetrahydrofuran).
The reaction was carried out at 6 ° C. for 6 hours.

When the amount of the remaining silicon hydride groups in the reaction solution was quantified by IR spectroscopy, almost no remaining silicon hydride groups remained. When the reactive silicon group was quantified by the NMR method, a polyoxypropylene-based polymer having about 1.7 (CH ₃ O) ₂ Si (CH ₃ ) CH ₂ CH ₂ CH ₂ O— groups per molecule at the molecular terminal was obtained. Coalescence was obtained.

Examples 1-4 and Comparative Examples 1-3 To 100 g of the polymer synthesized in Synthesis Example 1, 50 g of a thermoplastic phenol resin (PR50731, manufactured by Sumitomo Bakelite Co., Ltd.) and Nocrack NS-6 (Ouchi Shinko Chemical Co., Ltd.) 1.0 g) and aluminum trisethyl acetoacetate (5 g) were sufficiently mixed, and then Q-CEL200 manufactured by Asahi Glass Co., Ltd. or azobisisobutyronitrile, a decomposable foaming agent, was added in the amount shown in Table 1 and then slowly added After careful mixing, the mixture was coated on a silicon release paper with a coating thickness of 700 μm and cured at 120 ° C. for 10 minutes. After curing at 50 ° C for 7 days to complete the hardening, the density was changed to the tensile strength (Dumbbell JIS 3,
(Pulling speed 300mm / min, measurement temperature 23 ° C, use autograph)
Was measured. The results are shown in Table 1.

[Effect of the Invention] When the composition of the present invention is used, a light-weight and high-strength cured product can be obtained.

Claims (1)

(57) [Claims] 1. An oxyalkylene-based polymer 100 having (A) a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom and having at least one silicon-containing group capable of crosslinking by forming a siloxane bond. A curable composition comprising 1 part by weight and (B) 1 to 20 parts by weight of a glass balloon.