JPH0333564A - Material of silicone rubber composition for structural glazing sealant - Google Patents

Abstract

PURPOSE:To get high strength, high elongation and sufficient durability even in warm and humid ageing test by using colloidal calcium carbonate as sealing agent, which has a specified BET specific surface area and mean grain diameter. CONSTITUTION:A silicon rubber composition for structural glazing sealant consists of 100wt.% of polyorganosiloxane, whose molecular chain is closed at its end with silanol radical and has viscosity of 500 to 10,000cSt at 25 deg.C; 0.1 to 20wt.% of alkoxysilane and/or its partial hydrolysis condensate shown in a formula I, where R<1> and R<2> repress monovalent hydrocarbon radicals respectively, and (a) an integer among 0, 1 and 2; 10 to 200wt.% of colloidal calcium carbonate having BET specific surface area of 16.0 to 25.0m<2>/g and mean grain diameter of 0.05 to 0.20mum and treated on its surface by fatty acid; and 0.01 to 5weight% of hardening promoter. This composition has high strength, high elongation in hardened state and does not deteriorate even after long-term storage in warm water and warm moisture.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is applicable to structural glazing sealants because the physical properties of the rubber in the cured state are excellent in high strength and high elongation, as well as excellent moisture resistance and hot water resistance. The present invention relates to a silicone rubber composition useful as a silicone rubber composition.

[Technical background of the invention and its problems]

Conventionally, silicone rubber compositions that cure at room temperature and become rubber-like elastic bodies have excellent heat resistance and cold resistance, have little change in physical properties due to temperature changes, and are less likely to deteriorate due to ozone or ultraviolet rays. Since then, it has been widely used as an architectural sealant. Among these, silicone rubber is widely used in weather seals for the purpose of waterproofing.

In the field of architectural sealants, there is a structural glazing construction method in which sheet glass is attached to a frame using a sealant, but unlike weather seals, the strength of the rubber is important for the sealant used in this construction method, and high strength and Acetic acid-removed or aminoxy-removed silicone rubbers having high elongation properties are used.

However, this type of silicone rubber has problems in that it has an odor and is corrosive, has poor deep curing properties, requires a long time to cure, and is still lacking in strength.

For this reason, the application of dealcoholized silicone rubber, which has good curing properties and is odorless and corrosive, is being considered. However, this type of rubber lacks physical strength and elongation, and is subject to further deterioration tests, especially hot water and hot humidity degradation. The drawback is that the strength is significantly reduced in the test.

In order to achieve high elongation and low modulus in this dealcoholized silicone rubber, there is a method using calcium carbonate as a filler, which has an average particle diameter of 0.3 μm or less and a specific surface area of 3.0 m2/g or more by air permeation method. Showa 53
34855) has been proposed, but this method does not provide sufficient rubber strength, and furthermore, it has the disadvantage that strength and elongation are significantly reduced in hot water and hot-humidity deterioration tests. Furthermore, for architectural sealants, a method for evaluating the physical properties of sealants is described in JIS 5758 Section 5-12 for the tensile adhesion of rubber. A material with a stress of 15 kgf/cm2 or more and an elongation of 250% or more is strongly desired in structural glazing construction methods, and the development of a silicone rubber material that satisfies these requirements is awaited.

[Purpose of the invention]

The present invention solves the above-mentioned problems and provides a silicone rubber composition useful as a structural glazing sealant, which has high strength, high elongation, and has sufficient durability against temperature and humidity deterioration tests. purpose.

[Structure of the invention]

In order to improve the physical properties of dealcoholized silicone rubber sealants for structural glazing, the present inventors have achieved unprecedented high strength and high elongation by using a specific calcium carbonate as a filler. They discovered that it can last for a long time even in hot water and a warm and humid atmosphere, leading to the completion of the present invention.

That is, as a result of intensive study on improving the physical properties of dealcoholized silicone rubber sealant for structural glazing, the present inventors found that the BBT specific surface area was 6.0.
~25.0m2/g with an average particle size of 0.05~0.20μ
It has been discovered that by using colloidal calcium carbonate, whose surface is treated with fatty acids, as a filler, it is possible to obtain unprecedented physical properties and durability. This was completely unexpected based on the above-mentioned Japanese Patent Application Laid-Open No. 53-34855 and conventional knowledge.

That is, in JP-A-53-34855, the average particle diameter is 0.3 μm or less, the specific surface area is 3 as determined by the air permeation method,
By using calcium carbonate of 0 m2/g or more,
It is stated that it improves elongation and adhesion, but
In this case, as calcium carbonate, the particle surface is fatty acid,
Calcium carbonate with an untreated surface that is not covered with a surfactant is described, and there is no mention of the strength of silicone rubber, especially its tensile strength, resistance to temperature and humidity, and resistance to hot water.

On the other hand, the present inventors investigated the specific surface area and particle size of calcium carbonate, as well as the influence of surface treatment agents on dealcoholized silicone rubber, and found that strength and temperature/humidity resistance depend on the type of calcium carbonate and the surface treatment agent. We found that the hot water properties were affected, and among these, we found that the surface was coated with fatty acids with a BET specific surface area of 1 (1-25,0m2/g).
It was discovered that when colloidal calcium carbonate with a particle size of 0.05 to 0.20 μm was used as a filler, it exhibited excellent strength and resistance to temperature, moisture, and hot water. A useful silicone rubber composition has been completed.

That is, in the silicone rubber composition for structural glazing sealants of the present invention, (A) the terminal end of the molecule is blocked with a silanol group, and the viscosity at 25°C is 500 to 1.
Polyorganosiloxane with 00.000 cSt
100 parts by weight; (B) Formula R', 5i (OR2) 4-
(In the formula, R1 and R2 each represent a monovalent hydrocarbon group, and a is an integer of 0.1 or 2) and/or a partially hydrolyzed condensate thereof
0.1-20 parts by weight; (C)
10 to 200 parts by weight of colloidal calcium carbonate having a BIET specific surface area of 16.0 to 25.0 m'/g and an average particle size of 0.05 to 0.20 μm, the surface of which has been treated with a fatty acid; and (D) It is characterized by comprising 0.01 to 5 parts by weight of a curing accelerator.

The polyorganosiloxane which is the component (A) of the composition of the present invention is a silanic polymer whose both ends are blocked with silanol groups. Further, component (A) may contain a branched polymer.

The organic groups bonded to the silicon atom in the diorganosiloxane, which is the structural unit of component (A), may be the same or different, and include, for example, a methyl group, an ethyl group, a propyl group,
Alkyl groups such as butyl, hexyl and dodecyl; alkenyl such as vinyl and allyl; aryl such as phenyl and tolyl; aralkyl such as benzyl, β-phenylethyl and β-phenylpropyl and 3,3.3- ) U, monovalent substituted hydrocarbon groups such as fluoropropyl group, chloromethyl group, etc. can be mentioned. Among these, methyl, vinyl, or phenyl groups are preferred from the viewpoint of ease of synthesis.Moreover, when the organic group bonded to the silicon atom is a methyl group, the raw material The intermediate is easy to synthesize, and the viscosity is the lowest compared to the high degree of polymerization of the resulting polymer.
Moreover, it is most preferable because it has a favorable effect on the balance of physical properties of the rubber-like elastic body that is the cured product. For this reason, it is most preferable that substantially all of the organic groups are methyl groups, but if heat resistance is required for the cured product, it is preferable that some of the organic groups bonded to silicon atoms be phenyl groups. . Even when the polymer contains organic groups other than methyl groups, it is preferable that 85% or more of the total number of organic groups in the polymer be methyl groups for the reasons mentioned above.

In addition, such polyorganosiloxane has 25
The viscosity at °C is 500 to 100,000 cSt, preferably 1.000 to 50,000 cSt. If the viscosity is less than 500 cSt, it is difficult to impart excellent mechanical properties to the cured product, and if it exceeds 100,000 cSt, the viscosity becomes too high and the workability becomes poor in practical use.

The alkoxysilane and/or its partially hydrolyzed condensate, which is the component (D) of the composition of the present invention, is necessary for the composition to cure and become a good elastic body, and the alkoxysilane is the general formula R', 5i(OR2)<
-a (in the formula, R', R2 and a are as described above).

In the general formula, R1 includes alkyl groups such as methyl, ethyl, and propyl groups, phenyl groups, and vinyl groups, and R2 generally includes methyl and ethyl groups due to the hydrolyzability of OR'. Mention may be made of the propyl group.

Component (B) includes alkyl orthosilicates such as ethyl silicate and propyl silicate, and polyalkyl silicates that are partially hydrolyzed thereof, methyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, and vinyltriethoxysilane. Examples include alkoxysilanes such as silanes and partially hydrolyzed siloxanes thereof.

The blending amount of component (B) is 0.1 to 20 parts by weight per 100 parts by weight of component (A). If the amount of component (B) is less than 0.1 parts by weight, curing of the composition will be slow, and if it exceeds 20 parts by weight, the physical properties after curing will deteriorate, which is not preferred.

Component (C) of the composition of the present invention is an important component that imparts the characteristics of the present invention, and has a BBT specific surface area of 16.0 to 25.
It is colloidal calcium carbonate with a particle size of 0 m2/g, an average particle size of 0.05 to 0.20 μm, and a particle surface treated with a fatty acid.

In order to obtain high strength, high elongation, and excellent properties in temperature and humidity resistance and hot water resistance in the composition of the present invention, the average particle size should be 0.05 to
BET specific surface area of the surface with fatty acid at 0.20μm is 16
．． (A colloidal calcium carbonate treated within 1 to 25.0 m2/g is required. If the average particle size is less than 0.05 μm, the viscosity becomes too high and practical workability is poor;
If it exceeds 0 μm, excellent mechanical properties cannot be imparted to the cured product. The BBT specific surface area is also 16.0m
If it is less than 27 g, excellent mechanical properties cannot be imparted to the cured product, and if it exceeds 25.0 m2/g, the viscosity becomes too high and the workability is poor in practical use. Furthermore, the calcium carbonate must be colloid-based and the surface must be treated with fatty acids. Fatty acids include oleic acid, linoleic acid, dioxystearic acid, ricinoleic acid, etc. Among them, ricinoleic acid is the main component of castor oil that has been surface-treated with a substance made from hydrogenated castor oil. Calcium carbonate is preferable because it gives a cured rubber product with the highest strength and highest elongation, and maintains these physical properties even after a temperature/humidity resistance/hot water deterioration test.

Examples of such calcium carbonate include MSK-8, Calfine 200 (manufactured by Maruo Calcium ■, trade name), Hakuenka CCR, and Gelton 50 (manufactured by Shiraishi Kogyo ■, trade name).

The blending amount of component (C) is 10 to 200 parts by weight, preferably 50 to 150 parts by weight, per 100 parts by weight of component (8). If it is less than 10 parts by weight, excellent mechanical properties cannot be imparted to the cured product, and if it exceeds 200 parts by weight, the viscosity becomes too high and the workability is poor in practical use.

The curing accelerator which is component (D) of the composition of the present invention includes octanoic acid, zinc octoate, tin octoate, cobalt octoate, manganese octoate, lead octoate,
tin naphthenate, cobalt naphthenate, lead naphthenate,
Carboxylic acid metal salts such as tin oleate and zinc stearate; 2 Organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin diacetate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide; tetrapropyl titanate , tetrabutyl titanate, tetraoctyl titanate, and other organic titanate esters; diisopropoxy(acetylacetonato) titanium, diisopropyl bis(ethylacedoacetate) titanium, l, 3-
Examples include organometallic compounds such as titanium chelate compounds such as propylene dioxybis(acetylacetonato)titanium and 1,3-propylenedioxybis(ethylacedoacetate)titanium.

(D) The blending amount for 1132 minutes is 0.01 to 5 parts by weight per 100 parts by weight of component (8). If it is less than 0.01 part by weight, no catalytic effect can be obtained, and if it is in excess of 5 parts by weight, not only no further effect can be obtained, but also the heat resistance of the cured product is adversely affected, which is not preferable.

3 In addition to components (8) to (D), the composition of the present invention may optionally contain fillers such as diatomaceous earth, ground quartz, fumed silica, organosilane or siloxane-treated fumed silica; pigments such as , red iron, titanium dioxide,
Zinc white, ultramarine, etc. can be added. Further, depending on the purpose, an adhesion promoter or other polyorganosiloxane may be used in combination within a range that does not impair the effects of the present invention.

As adhesion promoters, for example, a group of alkoxysilanes well known as carbon functional silanes represented by the following molecular formula, and partially hydrolyzed siloxanes thereof can also be effectively used in the present invention. In addition, in the following description, Me is a methyl group, a
t each represents an ethyl group.

CH2= C(Me) co (CH2) 3Sl (
OMe) 3, /\ CH2CHCH20([:H2) 3Sl (OMe)
3,4 LN (CL) 21141 (CL) 3Sl (O
Me) 3, HooCC) IJH (Cf12) 3S+
(OBt)3.82N C684NH(CH2) 3
sI (OMe) 3 [Effects of the Invention] The composition of the present invention has excellent high strength and
It is useful as a structural glazing sealant because it exhibits high extensibility and does not deteriorate even when stored in hot water or humidity for a long period of time.

〔Example〕

Hereinafter, the present invention will be explained in further detail with reference to Examples and Comparative Examples. In addition, in Examples and Comparative Examples, all "parts" represent "parts by weight".

Example 1 Viscosity 50.0 with both molecular chain ends blocked with silanol groups
00 cSt polydimethylsiloxane, 2 parts phenyltrimethoxysilane, BBT specific surface area 18.0
m2/gs average particle size of 0.12 μm Colloidal calcium carbonate treated with fatty acid mainly composed of oleic acid 80 parts of Hakuenka CCRJ (manufactured by Shiraishi Kogyo ■, 5 products), 0.1 part of dibutyltin diacetate and T - 1 part of glycidoxypropyltrimethoxysilane was mixed and defoamed to obtain a composition of the present invention.

Next, in accordance with JIS A 57585-12, the first
This composition was applied onto the adherends shown in the table. Thereafter, this product was left to cure in an atmosphere of 20° C. and 55% RH for 14 days and then at 30° C. for 14 days to prepare a cured test specimen. A tensile adhesion test (initial stage) was conducted on this specimen at a speed of 50 mm/min, and a similar tensile test was conducted after immersing it in warm water at 50° C. for 7 days, 50 days, and 100 days. The results are shown in Table 1.

Comparative Examples 1 to 3 Comparative examples were prepared in the same manner as in Example 1, except that the fillers shown in Table 1 were added to 100 parts of polydimethylsiloxane in place of the calcium carbonate used in Example 1. A composition was obtained.

A tensile adhesion test similar to that in Example 1 was conducted using this composition. The results are shown in Table 1.

6 Example 2 Both ends of the molecule were blocked with silanol groups, viscosity 7.50
100 parts of 0 cSt polydimethylsiloxane, 3 parts of ethyl polysilicate, BUT specific surface area 23.5 m2/c
Colloidal calcium carbonate "Gelton 50" (manufactured by Shiraishi Kogyo ■, trade name) treated with hydrogenated castor oil fatty acid with an average particle size of 0.10 μm 140L 0.2 part of dibutyltin dilaurate was mixed and defoamed to produce the present invention. A composition was obtained.

Next, a cured test specimen was prepared using this composition in the same manner as in Example 1. Using this test specimen, the initial temperature and 60℃, 9
A tensile adhesion test was conducted after being left in a warm and humid environment of 5% Ill for 100 days. The results are shown in Table 2. Furthermore, using this composition, physical properties (initial and 60°C,
(After being left in a warm and humid environment at 95% RH for 100 days) was evaluated.

The results are shown in Table 2.

Comparative Example 4.5 Comparison was made in the same manner as in Example 2, except that instead of the calcium carbonate used in Example 2, a formulation was prepared in which each filler shown in Table 2 was added to 100 parts of polydimethylsiloxane. A composition was obtained.

Using this composition, the same tensile adhesion test and physical property evaluation as in Example 2 were conducted. The results are shown in Table 2.

Example 3 Viscosity 20.0 with both molecular chain ends blocked with silanol groups
00cSt polydimethylsiloxane 100 parts vinyltrimethoxysilane 2 parts BBT specific surface area 16.0m2
120 parts of colloidal calcium carbonate rMSK-A treated with fatty acids with an average particle size of 0.1 μm (manufactured by Maruo Calcium ■, trade name) and 0.2 parts of dibutyltin dioctoate were mixed and defoamed. A composition of the present invention was obtained.

Next, a cured test specimen (glass) was prepared using this composition in the same manner as in Example 1, and a tensile adhesion test was conducted.The initial and maximum tensile stress was 15. Okgf/cm2, elongation 2
Maximum tensile stress after immersion in 60%, 80°C hot water for 14 days 12.
It exhibited high physical properties of 2 Jf/cm2 and elongation of 340%.

Comparative Example 6 8 In Example 3, calcium carbonate MT-100CBET specific surface area 17.0 m2/g, average particle size 0.07 μm, surface resin acid treated product (manufactured by Maruo Calcium@, Comparative compositions were obtained in the same manner except that the following were used: (trade name)].

Next, tensile adhesion was performed using this composition in the same manner as in Example 3, and the initial maximum tensile stress was 10.6 kg.
f/cm2, elongation was 120%, maximum tensile stress was 6.4 kgf/am2, and elongation was 150% after immersion in 80°C hot water for 14 days.

9 1

Claims (1)

[Claims] 1(A) The molecular chain terminal is blocked with a silanol group, and the temperature at 25°C
100 parts by weight of a polyorganosiloxane having a viscosity of 500 to 100,000 cSt; (B) Formula R^1aSi(OR^2)_4_-_a (wherein R^1 and R^2 are each a monovalent hydrocarbon group and a is an integer of 0, 1 or 2) and/or a partially hydrolyzed condensate thereof (0.1 to 20 parts by weight); (C) BBT specific surface area of 16.0 to 25. 0m^2/g
and (D) 0.01 to 5 parts by weight of a hardening accelerator. Silicone rubber composition for structural glazing sealant. 2. The composition according to claim 1, wherein component 2 (C) is colloidal calcium carbonate surface-treated with a fatty acid made from hydrogenated castor oil.