JPH03149259A - High-strength, room temperature-curable polyorganosiloxane composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a room-temperature curable polyorganosiloxane composition that exhibits high strength after curing, and more specifically relates to a titanium oxide-based polyorganosiloxane composition that has been surface-treated with a metal oxide. This invention relates to a high-strength, room-temperature-curable polyorganosiloxane composition containing a filler.

[Prior art and problems] Silicone polymers have weak intermolecular forces, so even if various crosslinking agents are added to the polymer and cured, the resulting cured silicone product is a brittle rubber-like product with low strength. Its mechanical properties are not satisfactory in actual use.

Therefore, silicone mixed with various fillers is actually used. There are various types of fillers such as finely powdered silicone, diatomaceous earth, quartz powder, and calcium carbonate, depending on the application. It is used for different purposes. Among these, diatomaceous earth, calcium carbonate, and quartz powder have low reinforcing properties and are generally used mainly as fillers. On the other hand, fine powder silicone is used in many cases because it has great reinforcing properties and is highly effective in improving the mechanical properties of cured silicone products. However, when mixed with silicone in large quantities, Since significant thickening occurs, the filling amount is restricted, and therefore, even cured silicone rubber filled with finely powdered silicone rubber has not been obtained with sufficiently high mechanical properties and good workability.

As an improvement measure when filling with this fine powder silicate, organosilane, organosilazane, etc.
Methods of surface treatment with organopolysiloxane, etc., and methods of using various dispersants at the time of filling have been adopted. There are still not enough ways to make it excellent.

Cured silicone rubber is actually used with fillers mixed in as described above, but its mechanical properties are inferior to other rubbers and plastics, making it unsuitable for structural material applications and requiring special treatment. The problem was that it was only intended for specific applications, and therefore could not be used as a general-purpose material.

In addition, it is known that titanium oxide is added to silicone rubber as a pigment or filler, but it has been found that when titanium oxide that has been subjected to a certain surface treatment is used as a filler, the mechanical properties of silicone rubber are significantly improved. This was completely unexpected.

[Object of the Invention] The object of the present invention is to solve the above-mentioned problems of room-temperature-curable polyorganosiloxane compositions, and to provide a room-temperature-curable polyorganosiloxane composition that has good workability and excellent mechanical properties. It's about providing things.

[Structure of the Invention] As a result of studies to achieve the above object, the present inventors have found that by incorporating a titanium oxide filler whose surface has been treated with a metal oxide as a filler, good workability can be achieved. The present inventors have discovered that it is possible to obtain a room-temperature-curable polyorganosiloxane composition that has the following properties and has excellent mechanical properties, and has completed the present invention.

That is, the present invention provides (A) general formula % formula % (wherein -R1 is a hydrogen atom or a monovalent hydrocarbon group, R
2 is a substituted or unsubstituted monovalent hydrocarbon group and RO
(8) 100 parts by weight of a polydiorganosiloxane (group selected from the group consisting of C) Inorganic filler 0.5-50 heavy area (D) Crosslinking agent 0
40 parts by weight and (E) 0 to 5 parts by weight of a curing catalyst.

5 Component (A) constituting the composition of the present invention is a polydiorganosiloxane having a hydroxyl group or an alkoxy group at the end of the molecular chain, and is represented by the general formula %, where R1 is a hydrogen atom, methyl group, an alkyl group such as ethyl group, propyl group, butyl group, pentyl group, and R2 is an alkyl group such as methyl group, ethyl group, propyl group, cycloalkyl group such as cyclohexyl group, alkenyl group such as vinyl group, allyl group, etc. group, an aryl group such as a phenyl group, a tolyl group, or a group in which the hydrogen atom of these groups is partially substituted with a halogen atom, etc., and n is a group selected from the group consisting of RO. The viscosity of siloxane at 25°C is 50 to 10,000
A number greater than or equal to 3 within the range of 00 cSt+
If the viscosity of the composition is less than 50 cSt, the viscosity of the composition will be too low and there will be problems in handling.
A range of 0 to 100,000 cst is preferred.

Component (8) is an important component for imparting the high strength characteristics characteristic of the composition of the present invention. This component must be a titanium oxide filler whose surface is coated with a metal oxide. Examples of the titanium oxide filler include titanium oxide for pigments, particulate titanium oxide, and potassium titanate whiskers. The titanium oxide filler used in the present invention is obtained by treating the surface of the filler such as titanium oxide with a metal oxide such as tin oxide or antimony oxide to form a metal oxide film. By using such a titanium oxide filler in the composition of the present invention, a remarkable effect on improving mechanical properties is exhibited. The amount of component (B) added is as follows: (A) component 1
A range of 5 to 450 parts by weight per 00 parts by weight is preferred.
This is because if it is less than 5 parts by weight, it is difficult to obtain a cured silicone rubber product with excellent mechanical properties, and if it exceeds 450 parts by weight, the workability of the composition of the present invention will be poor.

Furthermore, component (C) is added in order to stabilize the high strength properties imparted by component (B). This ingredient is a filler commonly used in this type of silicone rubber composition, including finely powdered silicone, quartz powder, titanium dioxide, zinc oxide, aluminum oxide, calcium carbonate, magnesium carbonate, calcium silicate. , talc, diatomaceous earth, carbon black, ferric oxide, glass fiber, etc.

The amount of component (C) added is preferably in the range of 0.5 to 50 parts by weight per 100 parts by weight of component (A);
．． If less than 5 parts by weight, the mechanical properties become unstable;
This is because if the amount exceeds 0 parts by weight, the viscosity of the composition increases and the workability decreases.

The crosslinking agent of component (D) constituting the composition of the present invention is (A
) is crosslinked to form a network structure, and is known as a crosslinking agent for room temperature curable polyorganosiloxane compositions.

This is a general formula (wherein R3 is a monovalent hydrocarbon group, X is a hydrolyzable group,
And a is 0-2 W! silane or a partially hydrolyzed condensate thereof.

Examples of R3 include the same groups as those exemplified as R2 in component (A), and iminoalkyl groups represented by and.

Hydrolyzable groups represented by groups, ketoxime groups such as diethylketoxime groups: acyloxy groups such as acetoxy groups, octanoyloxy groups, benzoyloxy groups, dimethylamino groups,
Amino groups such as diethylamino group, butylamino group, cyclohexylamino group, dimethylaminoxy group - Aminoxy group such as diethylaminoxy group: Amide group such as N-methylacetamide group, N-ethylacetamide group, N-methylbenzamide group, etc. etc. are exemplified. Specifically, methyl silicate, ethyl silicate, probyl silicate 1~, methyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, methyltris(methoxyl-oxy)silane, vinyltris(methoxy) ethoxy)silane, methyltripropenoxysilane, vinyltripropenoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, methyltris(acetoneoxime)silane, vinyltris(acetoneoxime)silane, methyltris(methylethylketoxime)silane, vinyltris (methyl ethyl ketoxime) silane, methyl tris (
dimethylamino)silane, methyltris(diethylamino)silane, methyltris(N-methylacetamide)
Examples include silane, vinyltris(N-ethylacetamido)silane, and partial hydrolysates thereof. Also, hexamethylbis(diethylaminoxy)cyfurobutrasiloxane, tetramethyldibutylbis(diethylaminoxy)cyfurotetrasiloxane, heptamethyl(diethylaminoxy)cyclotetrasiloxane, pentamethyltris(diethylaminoxy)cyclotetrasiloxane, heptamethyl Examples include cyclic siloxanes such as bis(methylethylaminoxy)cyclotetrasiloxane and tetramethylbis(diethylaminoxy)mono(methylethylaminoxy)cyclotetrasiloxane. It is not necessary to be limited to these, and two or more types can be used together.

The amount of component (D) added is suitably in the range of 0 to 40 parts by weight per 100 parts by weight of component (A).

If component (A) itself has crosslinking properties, component (D) is not essential, but if it is packaged in one package, it is preferable to add it to some extent from the viewpoint of storage stability.
If it exceeds 1 part by weight, component (D) will be liberated and the curability and physical properties of the cured product will be impaired, which is not preferable.

Furthermore, as the curing catalyst for component (E) constituting the composition of the present invention, iron octoate, cobalt octoate,
Carboxylic acid metal salts such as manganese octoate, zinc off-l-ate, tin naphthinate, tin caprylate, tin oleate; dibutyltin diacetate-1-, diethyltin dioctoate-1-, dibutyltin dilaurate, diethyltin dioleate, oxidation Examples include organic tin compounds such as dibutyltin, diethyltin dimethoxide, dibutylbis(triel-xysiloxy)tin, and dioctylsmedilaureate; niamine compounds; quaternary ammonium salts; titanium chelate compounds.

The amount of component (E) added is within the range of 0 to 5 parts by weight per 100 parts by weight of component (A).The crosslinking agent of component (D) has autocatalytic properties like an aminoxy compound. In some cases, component (E) is not an essential component. If it exceeds 5 parts by weight, workability and storage stability may decrease, and heat resistance of the cured product may deteriorate, which is not preferable.

Other fillers and additives may be used in the composition of the present invention as necessary within a range that does not impair the purpose of the present invention. Other fillers include: These include reinforcing materials, non-reinforcing filler-like materials, conductive materials, heat dissipating materials, heat resistant materials, and the like. Additives include adhesion improvers, pigments, thixotropic agents, viscosity modifiers, ultraviolet inhibitors,
It is also possible to add various additives such as a fungicide, a solvent, a heat or cold resistance improver, and a flame retardant.

The composition of the present invention is obtained by mixing all of the above components and various additives as necessary in a moisture-blocked state.The obtained composition is stored as it is in a closed container, It can be used as a so-called one-pack room-temperature curable composition that is cured only by exposure to moisture in the air during use. Alternatively, the composition of the present invention may be prepared as a composition containing, for example, a crosslinking agent and a curing catalyst separately, stored separately in two or three separate containers as appropriate, and mixed together at the time of use, so-called one package. It can also be used as a mold room temperature curable composition.

[Effects of the Invention] The room-temperature curable composition obtained by the present invention has good workability before curing, and after curing, the mechanical properties of silicone rubber are improved and high mechanical strength is exhibited. In addition to the uses of conventional room temperature curable polyorganosiloxane compositions, the compositions of the present invention can
It is an extremely useful material that can be used for adhesion and sealing of materials, as well as new applications as a semi-structural material.

[Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the following Examples.

Note that all parts here represent parts by weight, and the viscosity is the value at 25°C.

Example 1 100 parts of hydroxyl end-capped polydimethylsiloxane with a viscosity of 5000 cst, 140 parts of titanium oxide spherical powder (500 parts, manufactured by Ishihara Sangyo Co., Ltd.) whose surface was coated with tin oxide/antimony oxide, and fume dosing. Rika 10
6.34 of ethyl orthosilicate) and mixed under reduced pressure to uniformly disperse the mixture.
1 part and 0.02 part of dibutyltin oxide were added and mixed in the absence of moisture to uniformly disperse the composition of the present invention.
Next, this composition was molded into a sheet with a thickness of 211 cm, and the composition was molded into a sheet with a thickness of 1.
A cured product was obtained by curing for one day, and its physical properties were measured. The results obtained are shown in Table 1.

Comparative Example 1 As a comparative example, a composition was prepared under the same conditions as Example 1, except that the same volume of KR-310 (manufactured by Titanium Kogyo Co., Ltd.) was used as titanium oxide other than those described in the present invention. death,
A cured sheet was similarly prepared.

The measurement results of the physical properties of this cured sheet are also listed in Table 1.

Comparative Example 2 As a comparative example, a composition was prepared in the same manner as in the composition described in Example 1 except for 10 parts of fumed dosilica, and a cured sheet was prepared from the obtained composition. The measurement results of the physical properties of this cured sheet are also listed in Table 1.

Table 1 Goyo Arrival Hardness Yugo S Stretching Elongation
Fengyu 11 suru (JIS A) (kgf/CIl12
) (X) (Oca) Example 2 Acicular titanium oxide powder (FT-loooo,
(manufactured by Ishihara Sangyo M) 220 copies, plus calcium carbonate 2
0 parts were added and mixed under reduced pressure to uniformly disperse the mixture.
Furthermore, 33 parts of 2G of methyl tris(methyl ethyl getoxime) silane and 0.03 parts of dibutyltin dilaurate were added and mixed in the absence of moisture to uniformly disperse the mixture to obtain a composition of the present invention. Next, a sheet was prepared using this composition in the same manner as in Example 1, and its physical properties were measured. The results are shown in Table 2.

Table 2 Workability Hardness Tensile strength Elongation Volume resistivity (ISA) (kc+f/cm (π) (Ω
Control Example 3 Titanium oxide spherical powder (W
-1, Mitsubishi Metals (stock number 1180 parts), and 15 parts of calcium carbonate were added and mixed under reduced pressure to uniformly disperse the mixture.
Adding 0.69 parts and 0.05 parts of dibutyltin oxide,
A composition of the present invention was obtained by mixing and uniformly dispersing it in the absence of moisture.Next, a sheet was prepared using this composition in the same manner as in Example 1, and its physical properties were measured.The results are shown in Table 3.

Table 3 Goyo Arrival Hardness Zum Button Sword Extension 11ul (JIS A) (kaf/aa2)
(!) (ocs) Example 4 Titanium oxide spherical powder (W-1O, manufactured by Mitsubishi Metals Corporation) in which 100 parts of hydroxyl end-capped polydimethylsiloxane with a viscosity of 3000 cst was surface-coated with tin oxide/antimony oxide. 135 parts and 12 parts of fumed dosilica were added and mixed under reduced pressure to uniformly disperse the mixture.Additionally, 8.28 parts of methyltripropenoxysilane
1 part and 0.10 part of cobalt octoate were added and mixed in the absence of moisture to uniformly disperse the mixture to obtain a composition of the present invention. Next, a sheet was prepared using this composition in the same manner as in Example 1, and its physical properties were measured.
Shown in the table.

= 18- Example 5 60 parts of titanium oxide spherical powder (500W, manufactured by Ishihara Sangyo Co., Ltd.) whose surface was coated with tin oxide/antimony #1 was added to 100 parts of hydroxyl end-capped polydimethylsiloxane with a viscosity of 3000 csl, and 60 parts of similarly coated potassium titanate whiskers (WK-200, manufactured by Otsuka Chemical Co., Ltd.) and 25 parts of titanium oxide for pigments were added and mixed under reduced pressure to uniformly disperse the mixture. Further, 12.88 parts of vinyltris(N-ethylacetamido)silane was added to this mixture and mixed in the absence of moisture to uniformly disperse the mixture to obtain a composition of the present invention. Next, a sheet was prepared using this composition in the same manner as in Example 1, and its physical properties were measured. The results are not shown in Table 5.

-19~ Table 5 Workability Hardness Tensile strength Elongation Volume resistivity (JIS^) (kgf/rA2)
(X) (Ω) Patent applicant Toshiba Silicone Corporation -+L-+-r, -jY) ~ 20 -

Claims (1)

[Claims] 1 (A) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, R^1 is a hydrogen atom or a monovalent hydrocarbon group,
R^2 is a group selected from the group consisting of a substituted or unsubstituted monovalent hydrocarbon group and R^1O, and n is a number of 3 or more)
100 parts by weight of polydiorganosiloxane (B) 5 to 450 parts by weight of a titanium oxide filler whose surface has been coated with a metal oxide (C) 0.5 to 50 parts by weight of an inorganic filler (D) Crosslinked A high-strength, room-temperature-curable polyorganosiloxane composition comprising 0 to 40 parts by weight of a curing agent and (E) 0 to 5 parts by weight of a curing catalyst.