JPS59155483A - Surface hardening silicone sealant composition - Google Patents

Abstract

PURPOSE:To provide the titled composition having excellent adhesive property, etc. prepared by adding an organoaminoxy group-containing organic silicon compd., an inorganic filler and a boric acid ester to a specified poly-diorganosiloxane. CONSTITUTION:The surface hardening silicone sealant composition is prepared by adding (B) 0.1-30pts.wt. organic silicon compd. having, on an average, two or more organoaminoxy groups in the molecule [e.g. Si(ONEt2)4, where Et is an ethyl group], (C) 5-300pts.wt. inorganic filler (e.g. calcium carbonate) and (D) 0.01-10pts.wt. boric acid ester of formula, B(OR)3 (where R is a 1-8C univalent hydrocarbon group) [e.g. B(OCH3)3] to (A) 100pts.wt. poly-diorganosiloxane which is blocked with a silanol group at the terminal and has a viscosity of 100-20,000cSt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface-curing silicone sealant composition, and more specifically, it is suitable as a sealant for joints in buildings and is mainly composed of polyorganosiloxane, which has surface-curing properties at room temperature. The present invention relates to a sealant composition as an ingredient.

Polyorganosiloxane compositions that harden at room temperature to become rubber-like elastic bodies are used in construction because they have excellent heat resistance, cold resistance, and weather resistance, and their physical properties change little with temperature and are less susceptible to deterioration due to ozone and ultraviolet rays. Widely used as a sealant. However, these curable polyorganosiloxane compositions require pretreatment of the adherend in order to achieve adhesion to the adherend, and depending on the type of adherend, adhesion may not be possible. there were.

As a result of studying methods for solving the above-mentioned problems, the present inventors discovered that a combination of a silanol group end-blocked polydiorganosiloxane and an organoaminoxy group-containing organosilicon compound, as previously disclosed in JP-A No. 57-90045, A polyorganosiloxane composition of the type that cures at room temperature by reaction to give a rubber-like elastomer has a temperature of 0. lmm
When this composition is cured by adding a secondary monohydric alcohol with a vapor pressure higher than Hg, the surface hardens to form an elastic film, but the interior remains sticky. It has been found that it is possible to obtain a sealing material that provides a cured product and can be bonded to various adherends without requiring pretreatment of the adhering surface of the adherend. This sealant composition is capable of adhering to adherends to which ordinary C room temperature curable polyorganosiloxane compositions cannot adhere. However, when this composition is applied to a joint with a shallow joint depth, the rubber-like hardened portion at the bonding surface between the adherend and the surface layer portion of the sealant (hereinafter referred to as the “surface layer portion”). Since it has poor adhesive properties, it has the problem of not having sufficient adhesive properties.

Further, JP-A-58-88!151 proposes a method of adding at least one of an alcohol compound and an alkoxy group-containing organosilicon compound. however,
This method also has the same problems as described above.

The object of the present invention is to provide a polyester that has good adhesion to adherends even in shallow joints, has surface hardening properties at room temperature, and is suitable as a sealing material for joints in buildings. An object of the present invention is to provide a silicone sealant composition containing organosiloxane as a main component.

As a result of further studies on how to solve the above problems, the present inventors discovered a room-temperature-curable polyorganosiloxane composition that is cured by the reaction of a silanol group-endblocked polydiorganosiloxane composition and an organosilicon compound containing an organoaminoxy group. By adding boric acid ester to the product,
The inventors have found that the above object can be achieved and have completed the present invention.

That is, the surface-curing silicone sealant composition of the present invention comprises: (A) 100 parts by weight of polydicasiloxane whose ends are capped with silanol groups and whose viscosity at 25°C is 100 to 200.0 QOcSt; ) 0.1 to 30 parts by weight of an organosilicon compound containing an average of more than 2 organoaminoxy groups in the molecule, (C) 5 to 300 parts by weight of an inorganic filler, and (D) general formula; OR)3 [wherein R represents a monovalent hydrocarbon group having 1 to 8 carbon atoms. ] It is characterized by consisting of 0.01 to 10 parts by weight of a boric acid ester represented by the following.

In the following, the invention will be explained in more detail.

The polydiorganosiloxane of component (A) used in the present invention is the same as the silanol-terminated polydiorganosiloxane commonly used in condensed polysiloxane compositions that cure at room temperature. ``(A)
The ingredients have a viscosity of 100 to 100°C at 25°C in order to give the sealant appropriate workability and physical properties suitable for use as a building sealant.
It must be in the range of 200,000 cSt. If the viscosity is less than 100 cst, the elongation rate after the reaction is completed will be insufficient;
If it exceeds 0.00 cSt, a homogeneous composition cannot be obtained and extrusion workability also deteriorates. A particularly preferable viscosity range is 500 to 50.0 in order to harmonize these two properties.
00 cst range.

Examples of organic groups directly bonded to the silicon atom of polyorganosiloxane include alkyl groups such as methyl, ethyl, propyl, butyl and hexyl groups; alkenyl groups such as vinyl and allyl groups; phenyl and tolyl groups; Aryl groups such as benzyl groups, phenylethyl groups; monovalent substituted hydrocarbon groups such as 3.3.3-trifluoropropyl groups, chloromethyl groups and β-cyanethyl groups, etc. is exemplified. Among these, monovalent hydrocarbon groups such as a methyl group, a vinyl group, or a phenyl group are preferred because they are easy to synthesize.In particular, when a methyl group is used, a raw material intermediate can be obtained most easily. In addition, it provides the lowest viscosity compared to the degree of polymerization of polysiloxane, and improves the balance between extrusion workability and physical properties of the sealant. It is more preferable that substantially all organic groups are methyl groups. However, if the sealant after curing is required to have cold resistance or heat resistance, it is preferable to use phenyl groups as part of the organic groups.

The organosilicon compound containing an organoaminoxy group, which is the component (B) used in the present invention, undergoes a dehydroxylamine reaction with the terminal silanol group of the polydiorganosiloxane, which is the component (A), and crosslinks the polydiorganosiloxane. It extends the chain length, and can be used with silane derivatives or linear, cyclic, or branched siloxane derivatives. (B) The number of organoaminoxy groups cr+ contained in t and minutes may be present in an average number of several degrees exceeding two in the molecule for the purpose of quickly thickening after use and exerting its function as a sealant. necessary, and
For the purpose of ensuring sufficient pot life, it is necessary that the number be less than three on average. In order to obtain a sealing material with particularly good reactivity and excellent physical properties, it is possible to use a combination of cyclic polysiloxanes containing 2 or 3 organoamic groups in one molecule. preferable. Examples of the organic group bonded to the organoaminoxy group include two monovalent hydrocarbon groups such as methyl, ethyl, propyl, butyl, and cyclohexyl groups, or two divalent hydrocarbon groups such as butylene and pentylene groups. One hydrocarbon group is mentioned. Among these, the use of ethyl group is
It is preferable because the raw materials are easily available, the synthesis is easy, the reactivity is good, and the organohydroxylamine released is easy to volatilize. Examples of organosilicon compounds containing such organoaminoxy groups include the following. Hereinafter, for the sake of brevity, the following abbreviations will be used for each organosilicon compound.

(Abbreviations) Me: methyl group, Et: ethyl group, Bu nibbutyl group, v
I: vinyl group, Ph: phenyl group.

E t 2NOM e 2S I S IM e 2
ONE t 2 , E t 2 NOMe2S IO
S + M e 2 ONE t2゜Et2NOMe2
SiOPh2SiOSiMe2ONEt2゜MeSi[
OMe2SiONEt2]3. PhSi[OMe2S
iONEt2] 3° The blending amount of such an organosilicon compound containing an orkaminoxy group is 0.1 to 30 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of component (A). If the amount of the organosilicon compound containing an organoaminoxy group is less than 0.1 part by weight, the reaction rate with the silanol end-blocked polydiorganosiloxane will be too fast and sufficient working time will not be obtained; If it exceeds this, the reaction rate will be slow and it will take a long time for the sealant to function as a sealing material, during which time problems such as rubbing off and cracking will likely occur.

The inorganic filler (C) component used in the present invention imparts appropriate viscosity to the sealant and has the physical properties required for architectural sealants, depending on the use, purpose, and processing conditions of the sealant. There is no particular restriction as long as the powder is an inorganic fine powder. Examples of the inorganic filler that can be scorched include fumed silica, precipitated silica, silica aerogel, ground silica, diatomite, iron oxide, titanium oxide, calcium carbonate, etc. One type is used. Among these inorganic fillers, it is particularly preferable to use calcium carbonate because a sealing material with high elongation and low modulus can be obtained.

The blending amount of such an inorganic filler is (A) component 10
5 to 300 parts by weight, preferably 30 to 0 parts by weight
It is 200 parts by weight. If the amount of inorganic filler is less than 5 parts by weight, the non-flowability necessary for use as a building sealant will be reduced to 1%, while if it exceeds 300 parts by weight, workability will decrease.

Such an inorganic filler may further be used as a coloring agent, for example,
Pigments such as titanium oxide, cobalt oxide, red iron oxide, carbon black, and phthalocyanine pigments may be appropriately added in amounts commonly used as colorants.

When the silicone sealant composition is cured, the boric acid ester used as component (D) in the uninvention cures the surface of the composition to form a good rubber elastic body, while leaving the inside in a sticky semi-cured state. It is an essential component that has the function of maintaining adhesive properties and also has the function of imparting excellent adhesion to various adherends without requiring pretreatment of the adherend.

Such boric acid esters are represented by the general formula; % formula %), and those in which R is a monovalent hydrocarbon group having 1 to 8 carbon atoms are used. If the number of carbon atoms in R is more than 8, not only the surface layer of the cured product will not exhibit sufficient comb elasticity, but also the internal tackiness of the cured product will be insufficient, which is not preferable.

Examples of such component (D) include the following compounds.

B(OCH3)3. B(OCH2CH3)3. B(OH
20H3]3)3゜B[0CH(OH)] B(
OCH2CJCH2CH2CH3)3゜23I B[0G)l CHC)I(II;)I)]
B[OGH0H(OH3)OH20H3]3°22
323' 2 The amount of such boric acid ester blended is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, per 100 parts by weight of component (A). The amount of borate ester is 0
．． If the amount is less than 1 part by weight, the internal tackiness of the composition and the adhesion of the surface layer of the cured product to the adherend will be insufficient, while if it exceeds 10 parts by weight, the rubber elasticity of the surface layer of the cured product will be insufficiently expressed. It becomes insufficient.

The surface-curing silicone sealant composition of the present invention is
, the main body consisting of components (A) and (C), component (B) as a curing agent, and component (D) as an additive are stored in separate containers, and the three components are mixed at the time of use. It is preferable to use it as

When the surface-curing silicone sealant composition of the present invention having the above composition is used, the surface of the cured product is cured to form an elastic film, but the inside of the cured product retains tackiness. It is. In addition, because it has good adhesion to adherends, it can be applied to various adherends without requiring pretreatment of the adherend, and it also has excellent adhesion on the surface layer. It is. Therefore, it exhibits good adhesion even in joints with shallow joint depths. The surface-curing silicone sealant composition of the present invention, which has numerous advantages, is suitable for use as a sealant for buildings. It has excellent adaptability to changes in the joint area.

The present invention will be explained in more detail below with reference to Examples.

In the examples, all parts represent parts by weight.

Example 1 100 parts of silanol group-endblocked polydimethylsiloxane having a viscosity of 5,000 cSt at 25°C were mixed with heavy lucium carbonate 56 jB having an average particle size of 1 g and stearic acid-treated light calsyl carbonate having an average particle size of 0.2. , mu50
A base compound was obtained by mixing using a kneader.

Samples 10 to 10 according to the present invention were prepared by mixing 3.0 parts of a crosslinking agent mixture consisting of
13 was prepared. At the same time, as comparative examples, Sample 14 in which monohydric alcohol was used instead of boric acid ester and Sample 15 in which boric acid ester was not added were prepared.

Test specimens shown in Figure 1 using each sample (adherent; 50 mm x 50 mm, 30 mm thick mortar, joint depth H); 5 mm, IJ+m, respectively.
and 15IIlffl, 1” pond width (W); 12m
m, joint length L); 50 mm) was created.

The prepared test specimens were cured for 4 days at room temperature, immersed in warm water at 50° C. for 48 hours, and then subjected to a tensile test. The results are simultaneously shown in the ff51 table. Figure 2 shows a cross section of the test specimen after curing was completed.

As is clear from the results in Tables 1 and 2, it was confirmed that the silicone sealant composition of the present invention has excellent physical properties.

Example 2 65 parts of rosin acid-treated precipitated calcium carbonate having an average particle size of 0.8p were added to 100 parts of silanol group-terminated polydimethylsiloxane having a viscosity of 3,000 cSt at 25°C, and mixed using a kneader. , the base compound was obtained.

Samples 20-22 according to the present invention were prepared by mixing 4.0 parts of a crosslinking agent mixture consisting of: At the same time, as comparative examples, sample 23 in which m alcohols were used instead of boric acid ester and sample 24 in which no boric acid ester was added were prepared.

Using each sample, a test was conducted in the same manner as in Example 1, except that unglazed tiles were used as the adherend instead of mortar. The results are also shown in Table 2.

As is clear from the results in Table 2 and above, it was confirmed that the silicone sealant composition of the present invention has excellent physical properties.

Example 3 To 100 parts of silanol group-endblocked polydimethylsiloxane having a viscosity of 10,000 cSt at 25°C, 5 parts of stearic acid-treated light calcium carbonate having an average particle size of 0.5-
Stearic acid-treated colloidal calcium carbonate with 0 parts and an average particle size of 0.05-! Part of lrO was added and mixed using a kneader to obtain a base compound.

Samples 30 and 31 according to the invention were prepared by mixing 2.5 parts of a crosslinking agent mixture consisting of
was prepared. At the same time, as comparative examples, Sample 32 in which monohydric alcohol was used instead of boric acid ester and Sample 33 in which boric acid ester was not added were prepared.

Using each sample, a test was conducted in the same manner as in Example 1, except that lightweight foamed concrete 1 was used instead of 1 mortar as the adherend.

The results are also shown in Table 3.

As is clear from the results in Table 3 and above, it was confirmed that the silicone sealant composition of the present invention has excellent physical properties.

Example 4 100 parts of silanol-terminated co-, I-chain polydimethylsiloxane having a viscosity of 7,500 cSt at 25°C
50 parts of light calcium carbonate with an average particle size of 0.5 and an average particle size of 0.5. 25 parts of Q51L stearic acid-treated colloidal calcium carbonate was added and mixed using a kneader to obtain a base compound.

Samples 40-46 according to the present invention were prepared by mixing 3.0 parts of a crosslinking agent mixture consisting of:

Using JZ samples 40 to 46, the test specimen shown in FIG.
Adherent: mortar, joint depth: 12 mm) was prepared. Each of the prepared test specimens was aged and cured at room temperature for 14 days. Next, each test specimen was attached to a fatigue testing machine and subjected to compression and elongation deformation repeatedly 20,000 times to achieve compression and elongation of ±20%, and then the presence or absence of abnormalities in each sample was observed. The results are shown in Table 4.

As is clear from the results in Table 4 and above, no abnormality was observed in the surface-curing silicone sealant composition of the present invention even after 20,000 repeated fatigue tests. It has been confirmed that it has excellent durability and strength.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a test specimen for tensile tests and cyclic fatigue tests, and FIG. 2 is a cross-sectional view thereof. Engineering: sample, 2: adherend, 3:
... Sample (rubber-like cured layer), 4... Sample (adhesive semi-cured layer), 5... Hard urethane foam (independent @), H...・Joint depth, W...
...Joint width, L...Joint length. 1st check

Claims (1)

[Claims] 1. (A) The terminal is blocked with a silanol group, and the 25°
100 parts by weight of a polydiorganosiloxane having a viscosity in C of 100 to 200,000 cSt. (B) 0.1 to 30 parts by weight of an organosilicon compound containing an average of more than 2 organoaminoxy groups in the molecule, (C) 5 to 300 parts by weight of an inorganic filler, and (D) general formula; 'B(OR)3 [Wherein, R represents a monovalent hydrocarbon group having 1 to 8 carbon atoms. ] A surface-curable silicone sealant composition comprising 0.01-10 parts by weight of a boric acid ester represented by the following. 2. The surface-curable silicone sealant composition according to claim 1, wherein 85% or more of the organic groups in component (A) are methyl groups. 3. The surface-curable silicone sealant composition according to claim 1, wherein the organic group bonded to the aminoxy group of component (B) is an ethyl group. 4. The surface-curable silicone sealant composition according to claim 1, wherein the inorganic filler as component (C) is calcium carbonate.