JPH02196860A - Curable 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] The present invention relates to curable silicone rubber compositions.

More particularly, the present invention relates to self-bonding, low modulus, one-pack room temperature vulcanization (RTV) compositions comprising a diorganosiloxane polymer, a crosslinking agent, and a crosslinking catalyst.

Nltzsche and Ni
According to U.S. Pat. No. 3,065,194 of ck),
1) a linear organosiloxane polymer having terminal hydroxyl groups; (2) a polyfunctional organosilicon crosslinking agent; and (3) an essentially anhydrous state consisting of a metal salt, chelate compound, organometallic compound, acid or base that acts as a crosslinking catalyst. A group of silicone rubber compositions is disclosed comprising a mixture of. Such compositions vulcanize or harden to a rubbery solid when exposed to moisture, and they can be sealed and stored in a container, such as a caulking tube, for extended periods of time. They have particular utility because they can then be applied by the user and cured by contact with water or steam. Such compositions can be used as sealants, electrical insulation, coatings, dental cements, caulking compounds,
It is usefully used as expansion joints, gaskets, cushioning materials, adhesives, and many other forms. According to the Nitze et al. patent, the composition comprises 100 parts of siloxane polymer, 0.1 to 50 parts of crosslinking agent, and
It is generally stated that the composition contains a crosslinking catalyst of 100%. The ratio of crosslinking agent to crosslinking catalyst is not specified;
In embodiments that include silane as the crosslinking agent and metal salts as the crosslinking catalyst, this ratio varies from less than 1 to more than 1.

Further previous teachings regarding one-package room temperature vulcanizable silicone compositions can be found in the following documents.

Brown et al., U.S. Pat. No. 3,161,614 (in which a pre-reactant of a silanol chain-terminated diorganopolysiloxane and a crosslinking agent is combined with a crosslinking catalyst); Cooper, U.S. Pat. No. 3,383. No. 355 (which deals with the preparation of alkoxy chain-terminated linear siloxane polymers using neutral finely divided solid catalysts such as Fuller's earth), Matho.
U.S. Pat. No. 3,499.859 to rly (herein:
using a hydrocarbonoxy end-capped diorganopolysiloxane and a metal-containing curing catalyst with boron nitride)
, and Cooper et al., U.S. Pat. No. 3,542,901.
(Here, a linear siloxane having a di- or trifunctional chain-end capping unit, and a linear siloxane having a chemically non-functional, inert chain-end capping unit at one end and a di- or trifunctional chain-end capping unit at the other end) A mixture of linear siloxanes with functional chain-end capping units is used, along with catalysts and crosslinking agents).

Also related are Brown et al., U.S. Pat. No. 3,170.894 (in which an organopolysiloxane intermediate containing condensable polyhydrocarbonoxy-type groups is combined with a catalyst), and Vey
anborg U.S. Pat. No. 3,175,993 (herein, alkoxylated silica
ne), which combines an organopolysiloxane intermediate end-capped with a catalyst with a catalyst).

Smith and Hamilton
U.S. Pat. No. 3,689,454 and U.S. Pat.
No. 779.986, Wcyenbe
U.S. Pat. However, in the composition by Smith et al., a titanium ester catalyst is used in place of a metal salt such as Nitsutsue, which causes gelation during mixing and undesirable viscosity. Growth can be more easily controlled and the composition can be stored for a longer period of time prior to use. Although these above cited references disclose the use of crosslinking agents and titanium ester catalysts over a wide range of compositions, the ratios between these compounds are not particularly limited and in all examples the crosslinking The ratio of agent to catalyst is always greater than 2. Additionally, in the Smith and Hamilton and Uyenberg patents, it is preferred that the silane be present in an amount greater than the silicon-bonded hydroxyl groups in order to prevent the system from gelling, and their invention The amount of catalyst in is always selected to be less than half of the amount of crosslinking agent used.

While this wide selection of ingredients may prove useful in the preparation of one-pack RTV compositions, the relevant factors to ensure specific properties of the cured silicone rubber are unknown. It is not always well known by the industry. For example, it is known that some changes in the properties of the cured composition can occur by varying the molecular weight of the polydiorganosiloxane having silanol chain end groups. For example, the elongation of rubber increases with increasing molecular weight. On the other hand, using a material with a lower viscosity results in a denser cure, which reduces elongation of the cured material and increases hardness. The adhesion of the cured composition to a variety of common substrates is also a possible factor with predictable effects, and this is generally due to the inclusion of monofunctional silane chain terminators along with crosslinking agents and, in special cases, adhesion promoters. Can be changed by adding In any case, modulus and adhesion are not easily controlled, and there is still much room for improvement at the current state of the art.

When ordinary ingredients are used in suitably selected novel proportions,
It has been discovered that a self-bonding, low modulus, one-pack room temperature vulcanizable silicone rubber composition can be obtained which has an excellent tensile strength to elongation relationship, ie, low tensile strength and very high elongation. Furthermore, compositions are provided that provide self-bonding adhesion to many substrates that are normally difficult to achieve, reducing the need for the use of adhesion promoters and even allowing their omission from the composition.

These results are unexpected since the compositions of the present invention require a ratio of catalyst to crosslinker of at least 0.5:1 (
As in the prior art, the ratio of catalyst to crosslinker is always at least 1, and in the most preferred compositions the ratio of catalyst to crosslinker is always at least 1. Because it will be. In preferred cases, the silane crosslinking agent is used in an amount less than previously thought necessary to bond all of the silanol groups in the substrate product and prevent gelation. No such gelation was observed when the metal ester catalyst was present in an amount greater than half the amount of silane.

According to the present invention, there is provided a liquid composition that is stable under substantially anhydrous conditions and cures in the presence of moisture to a self-bonding elastic solid, which composition comprises (a
) Polydiorganosiloxane having 100 parts by weight of silanol chain end groups of the following formula: (wherein R and R1 are each 8 carbon atoms individually selected from hydrocarbyl, halogenated hydrocarbyl, and lower cyanoalkyl) (b
)0.01 to 5.0, preferably 0.1 to 0.0.
95 parts by weight of a crosslinking silane of the following formula: R25L(OR3)41, where R2 and R3 have the meanings defined above for R and R1, and m has a value from 0 to 3, and the composition 0 to 1.99 relative to the total amount of silane in the substance
); and (c) 0.1 to 10
parts by weight of a silanol-reactive organometallic ester compound having groups attached to the metal atom, at least one of these groups being a hydrocarbonoxy group or a substituted hydrocarbon group. carbonoxy group, the above group is bonded to the metal atom via M-0-C bond, M is the metal and the remaining valence of the metal is bonded to the metal atom via M-0-C bond. An organic group, -OH, attached to an atom.

and a substituent selected from 10- in the M-0-M bond, and the weight ratio of component (C) to (b) is always greater than O,S:1, preferably 1
bigger.

Another preferred feature of the invention comprises preparing a composition as defined above under substantially anhydrous conditions and subsequently exposing the composition to moisture until the composition is cured into a rubbery material. A manufacturing method is provided.

RTV compositions of the invention average at least about 2601
an alkoxy group bonded to 1 silicon atom
It is prepared by simply mixing a polydiorganosiloxane having one or more of the aforementioned silanol chain end groups, a crosslinking silane compound, and a silanol-reactive organometallic ester. It is preferable to keep each component at room temperature during mixing. Since silanes are susceptible to hydrolysis when in contact with moisture, care must be taken to exclude moisture during the addition of silanes to polydiorganosiloxanes having silanol chain end groups. Similarly, if the composition is to be stored for an extended period of time prior to converting the composition to a cured solid elastomeric silicone rubber state, the silane, silanol reactivity may be Care must be taken to maintain the polydiorganosiloxane with silanol chain end groups under substantially anhydrous conditions. On the other hand, if the mixture is to be cured immediately after preparation, no special precautions are necessary beforehand and the three components can be mixed to form the desired form or shape in which the composition is cured.

The amount of silane crosslinker component mixed with the polydiorganosiloxane having silanol chain end groups can vary within wide limits. However, to obtain the best results, it is preferred to add 1 mole or less of silane per mole of silanol groups in the polydiorganosiloxane containing the silanol chain end groups of component (a).

Furthermore, it is preferable that the amount of organometallic ester used is such that the total number of moles of silanol-reactive ester bonds is equal to or larger than the total number of moles of terminal silanol groups in the polydiorganosiloxane of component (a). .

Without being bound by any theory of operation, the ratio of such components facilitates the formation of a silicone-based polymer that is wholly or partially chain-terminated with organometallic ester linkages, and these ester linkages is an unstable compound that is silanol-reactive and easily hydrolyzed together with a silicone crosslinker that has sufficient functionality.
O-M bonds are formed resulting in a novel combination of tensile strength and elongation as well as better adhesion in the cured product.

Within the above range, in the most preferred composition the weight ratio of component (C) to (b) is from 1 to 50;
Particularly preferably from 1 to 10. It is particularly preferred that the ff1l ratio of (C) to (b) is from 1 to 5.

The composition can be formed by mixing each component alone or with conventional fillers, additives, etc. Optionally, it is also possible to use inert solvents, ie solvents that do not react with the silanols or silicon-bonded alkoxy groups. Suitable solvents include hydrocarbons such as benzene, toluene, xylene or petroleum ether; halogenated solvents such as perchlorethylene or chlorobenzene; organic ethers such as diethyl ether and dibutyl ether; ketones such as methyl isobutyl ketone. There are also liquid polysiloxanes that do not contain hydroxyl groups. It is particularly effective to use a solvent when the polydiorganosiloxane having silanol chain end groups as component (a) is a high molecular weight gum. The solvent reduces the overall viscosity of the composition and speeds up curing. RTV compositions may be stored in a solvent until they are used. This is particularly useful when the gummy composition is used in coating applications.

Ingredients can be selected from a wide range to form the compositions of the present invention, as long as each component is used in the ratios specified above. These are Smith and Hamilton U.S. Patent Section 3,779.
,986.3,065,194.3,294,739.
No. 3,334.067 and No. 3,7011.467, among others.

Referring to component (a), the polydiorganosiloxanes having silanol chain end groups, these may be selected from those represented by the following formula:

where R and R1 are each an organic group of up to 20, preferably up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl and lower cyanoalkyl groups, and n is usually about 10 to 15, 000
．． Preferably the number varies between about 300 and about 5.200, and more preferably between 370 and 1,350.

Polydiorganosiloxanes having silanol chain end groups are well known in the art and include compositions having different R and R1 groups. For example, if the group R is methyl and R1
The group may be phenyl, betacyanoethyl or both. Further within the definition of polydiorganosiloxanes useful in this invention are dimethylsiloxane units,
Copolymers with silanol chain end groups consisting of diphenylsiloxane units and methylphenylsiloxane units, or copolymers of diorganosiloxane units of various types, such as copolymers consisting of dimethylsiloxane units, methylphenylsiloxane units and methyl and nylsiloxane units. is included. Preferably at least 50% of the R and R1 groups in the polydiorganosiloxane having silanol chain end groups are alkyl groups, such as methyl groups.

In the above formula, R and R1 are monocyclic aryl groups such as phenyl, benzyl, tolyl, xylyl and ethylphenyl; 2,6-dichlorophenyl, 4-bromophenyl, 2,5-difluorophenyl, 2.4. 6-
halogenated monocyclic aryl groups such as trichlorophenyl and 2,5-dibromophenyl; methyl, ethyl,
Alkyl groups such as n-propyl, isopropyl, n-butyl, 5ee-butyl, isobutyl, tert-butyl, amyl, hexyl, heptyl, octyl; vinyl,
Alkenyl groups such as allyl, n-butenyl-1, n-butenyl-2, n-pentenyl-2, n-hexenyl-2,2,3-dimethylbutenyl-2, n-hebutenyl;
Alkynyl groups such as propargyl, 2-butynyl; chloromethyl, iodomethyl, bromomethyl, fluoromethyl, chloroethyl, iodoethyl, bromoethyl, fluoroethyl, trichloromethyl, short ethyl, tribromomethyl, trifluoromethyl, dichloroethyl, chloro-〇 -propyl, bromo-n-propyl, iodoisopropyl, bromo-n-butyl, bromo-te
rt-butyl, 1.3.3-)chlorobutyl, 1.3
．． 3-tribromobutyl, chloropentyl, bromopentyl, 2,3-dichloropentyl, 3,3-dibromopentyl, chlorohexyl, bromohexyl, 1,4-dichlorohexyl, 3,3-dibromohexyl, bromooctyl, etc. halogenated alkyl group; chlorovinyl,
Bromovinyl, chloroallyl, bromoallyl, 3-20
rho-n-butenyl-1,3-chloro-n-pentenyl-
1,3-fluoro-n-hebutenyl-1,1,3,3-
) lychloro n-hebutenyl-5,1,3,5-) lychloro n-octenyl-6,2,3,3-) halogenated alkenyl groups such as dichloromethylbentenyl-4;
Halogenated alkynyl groups such as chloropropargyl, bromopropargyl; cyclopentyl, cyclohexyl, cyclohebutyl, cyclooctyl, 6-methylcyclohexyl, 3,3-dichlorocyclohexyl, 2.6-
dibromocycloheptyl, 1-cyclopentenyl, 3-
Methyl-1-cyclopentenyl, 3,4-dimethyl-1
-cyclopentenyl, 5-methyl-5-cyclopentenyl, 3゜4-dichloro-5-cyclopentenyl, 5-(
tert-butyl)-1-cyclopentenyl, 1-cyclohexenyl, 3-methyl-1-cyclohexenyl, 3
．． Cycloalkyl, cycloalkenyl and alkyl or halogenated cycloalkyl and cycloalkenyl groups such as 4-dimethyl-1-cyclohexenyl; and cyanomethyl, beta-cyanoethyl, gamma-cyanopropyl, delta-cyanobutyl and gamma-cyanoisobutyl. It is a lower cyanoalkyl group.

Mixtures of various polydiorganosiloxanes chain-terminated with silanol can also be used.

Although the silanol-chain-terminated materials useful in the RTV compositions of the present invention have been described as polydiorganosiloxanes, such materials may also contain small amounts, e.g., up to about 20%, of monoalkylsiloxane units, such as monomethylsiloxane. units and monoorganosiloxane units such as monophenylsiloxane units. See, for example, Beers US Pat. Nos. 3.382.205 and 3,438.930.

The polydiorganosiloxanes having silanol chain end groups used in the practice of the present invention can range from a thin liquid with low viscosity to a viscous gum, depending on the value of n in the above-mentioned maximum and the nature of the particular organic group represented by R and R1. It exhibits a wide variety of properties. The viscosity of component (a) has a very wide range, for example in the range from 30 to 10,000,000 cp at 25°C. Preferably the viscosity at 25°C is 2
0.000 to 1,000.000 cp and most preferably about 20,000 to 200.000 cp.

The silane crosslinking agent of component (b) with the formula: % formula %) is R2 and R3.
The contents of are the same as those defined for R and R1 above.

Examples of such silanes useful in the RTV compositions of the present invention are as follows.

CHzSL (OCHL)3, CHzSL (OCHz
CH3)3, (CHl)koS&(OCHs)2,
(CHz)! 5LOCHs, CH3CH2CH2CH2
CH2CH2CH2CH3 Milk (OCH))3, CFz
CH25= (OCR), NCCH, CHzS
L (OCRs)! , CH3S, (OCH2CH2
CH2CHz)s.

These silanes are well known in the art and are described, for example, in U.S. Pat. No. 2,843.5 to Berrldge.
It is described in No. 55.

When a silane is used as a crosslinking agent, the value of m in the above formula is 1 and the preferred silane is CIs SL (O
CHa ) 3. If it is desired to use a chain extender with the crosslinker, the value of m is 2, making the silane difunctional. A preferred difunctional silane is (OH3
) 2 SL (OCH3)2. Inclusion of chain extenders increases the elasticity of the final cured product. The same effect may be obtained using a liquid containing higher molecular weight silanol chain end groups. However, in this case, the viscosity of the curable composition also increases, making handling extremely difficult.

The modulus of elasticity is further improved by using a silane with a value of m of 3 in the above-mentioned maximum. A preferred silane for this purpose is (CHz)25LocH3. The use of such -functional silane chain termination units in combination with the above-mentioned crosslinkers and optionally added silanes as chain extenders not only increases the modulus but also often improves the base of the cured composition. Adhesion to materials is further improved.

Preferred silanes of the above formula contain an average of 1.05 to 3 silicon-bonded alkoxy groups per silane when a liquid containing two silanol-containing end groups is used. This number of alkoxy groups is simply 2
If so, this only increases the chain length. In this case, average means the quotient of the total number of alkoxy groups bonded to silicon atoms divided by the total number of silane molecules used in the RTV composition.

Regarding the silanol-reactive organometallic ester of component (c), the metal types, apart from silicon, range widely due to the need to form selectively hydrolyzable 15L-0-M bonds. be able to. Preferably the metal is lead, tin, zirconium, antimony,
Iron, cadmium, barium, calcium, titanium, bismuth, manganese, zinc, chromium, cobalt, nickel,
Selected from aluminum, gallium or germanium. The most preferred metal is titanium.

The organometallic compound is preferably an orthoester of a lower aliphatic alcohol, a partially chelated compound of a lower aliphatic alcohol and a β-dicarbonyl compound, or a partial hydrolysis product of these compounds, which contains metal atoms. It has at least one hydrocarbonoxy U or substituted hydrocarbonoxy group bonded to via an M-0-C bond.

Of particular interest are partially chelated organometallic esters, and especially titanium compounds of the formula:

Alternatively, in the above formula, R4 is a hydrogen atom or an organic group of up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, or carboxyalkyl, and R5 is selected from hydrocarbyl, halogenated hydrocarbyl, and lower cyanoalkyl. 8fl carbon atoms! In addition to the same group as R4 above, R6 is selected from halogen, cyano, nitro, carboxyester or acyl, and hydrocarbyl substituted with halogen, cyano, nitro, carboxyester or acyl;
and the total number of carbon atoms in the alkanedioxy group substituted with R6 does not exceed about 18, and R7 is a hydrogen atom or an organic group of up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, or acyl cyclic hydrocarbon substituents of up to 12 carbon atoms together with the carbon atoms to which they are attached when taken together with R5 or chlorine;
forming said substituents substituted with at least one of nitro, acyl, cyano or carboxy ester substituents; X is hydrocarbyl, halogenated hydrocarbyl, cyanoalkyl, alkoxy, halogenated alkoxy, cyanoalkoxy, amino or (CQH2
QO) v Indicates a group with up to 200 carbon atoms selected from ether or polyether groups of R, q is 2 to 4, ■
is a number from 1 to 20, R is as defined above, and a
is 0 or an integer within 8, and when a is 0, the CR' groups in the formula are cyclically bonded to each other, and R8 is selected from hydrocarbyl, halogenated hydrocarbyl, or cyano-substituted lower alkyl. A group of up to 8 carbon atoms.

These compounds are made by reacting a β-dicarbonyl compound and a titanium compound to form a dialkoxytitanium chelate compound.

This dialkoxytitanium chelate is then reacted with the corresponding alkanediol to obtain a fully cyclically substituted chelated titanium compound. For the production of such compounds, see U.S. Pat. No. 3,689,454 and U.S. Pat.
．． No. 067 and 3,70 Jll, No. 467.

Examples of such compounds are shown below.

Other examples will be readily apparent from the description of the substituents on the titanium atom. Most preferred, in view of the highest elongation, tensile and peel strength, is when component (c) has the following formula:

The RTV compositions of the present invention can also be modified by including various extenders or fillers. Examples of the many fillers that can be used in the compositions of the invention include titanium dioxide, lithopone, zinc oxide, zirconium silicate, silica aerogel, iron oxide, diatomaceous earth, calcium carbonate, fumed silica, silazane. Treated silica, precipitated silica, glass fibers, magnesium oxide, dichromium oxide, zirconium oxide, aluminum oxide, crushed quartz, baked clay, asbestos, carbon,
There are graphite, cork, cotton, synthetic fiber, etc.

The most useful fillers include calcium carbonate by itself or mixed with fumed silica. Also particularly suitable for use in the RTV compositions of the present invention is U.S. Pat. No. 2.938.009 to Lueas.
U.S. Pat. No. 3,004.859 to Nvalner, and U.S. Pat.
There are silica fillers treated with organosilicone or silazane such as those described in No. 5,743. The filler is generally present in an amount of about 5 to about 200 parts per 100 parts of the silanol chain end-containing polydiorganosiloxane component (a).
Parts by weight are used, preferably from about 10 to about 100 parts by weight.

In addition to fillers, the compositions of the invention may optionally contain adhesion promoters, for example in amounts of 0.2 to 2 parts of such promoters per 100 parts of component (a). These are generally nitrogen-containing compounds, such as acetonitrile. A preferred class of accelerators are those of the formula:

In the above formula, G is the same group as RIG defined below, (R
lIO) R111-S; -R' group is stylyl, vinyl, allyl, chloroallyl, or cyclohexenyl, and R9 is alkylene-arylene, alkylene, cycloalkenyl, and substituted such Na2
R111 is a group of up to 8 carbon atoms selected from hydrocarbyl and halogenated hydrocarbyl groups, and R11 is of the type defined for R1 above. or lower cyanoalkyl group, and b is 0 to 3.

Such accelerators are described in Berger, US Pat. No. 301,637, filed October 27, 1972, now abandoned. Most preferred among such accelerators are 1. 3. 5-tris-trimethoxysilylpropyl isocyanate and bis-1,
3-) Rimethoxysilylbrobyl isocyanurate.

In addition to fillers and adhesion promoters, the compositions of the invention contain
．． 3 to 20 ffiffi parts of a thixotropic or viscosity-lowering agent in the form of a low molecular weight linear polydiorganosiloxane may be included. Preferred types of such viscosity reducing agents are those represented by the following formula.

In the above formula, RlI and RI3 are each an organic group of up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, and lower cyanoalkyl; R14 and RIS are individually hydrogen or RlI and l'(+3
X has a value of 2 to 46.

The most preferred such thixotropic agent is a viscosity reducing agent of the above formula in which RH and RIS are methyl and R12
and R13 are methyl or methyl and phenyl in a ratio of about 70:30 and X is an integer from 3 to 50.

Additionally, other conventional ingredients such as flame retardants, stabilizers,
Pigments, reinforcing materials, etc. may be mixed.

The compositions of the invention are stable in the absence of moisture.

Therefore, they can be stored for a long period of time without being adversely affected. No significant changes occurred in the physical properties of the room temperature vulcanized composition during this storage period. This is particularly commercially advantageous since the composition can be prepared to have a certain consistency and setting time, both of which will not change appreciably on storage.

Storage stability is one of the characteristics that makes the compositions of the present invention useful as one-package liquid systems.

A composition prepared by anhydrous mixing of a metal ester catalyst and a silane with a polydiorganosiloxane having silanol chain end groups can be prepared by simply introducing the composition into the atmosphere at the desired location without the need for further modification. By exposing it to moisture and curing it,
Can be used in many sealing, filling and coating applications. When the compositions of the invention are exposed to moisture in this way, even after being stored for many months, they form a "film" on their surfaces in a relatively short period of time, e.g., within about 8 hours, at room temperature, e.g. It hardens to a rubbery state within a few days at temperatures ranging from 25°C to 25°C.

When components other than the polydiorganosiloxane having silanol chain end groups, the silane crosslinking agent, and the metal ester catalyst are included in the composition of the present invention, these additional components can be added by any method. However, to facilitate manufacturing, a "matrix" formulation is created consisting of the silane, metal ester, and all other ingredients except for the sometimes added accelerator, and from this matrix formulation, e.g. It is often very advantageous to remove the moisture by removing the moisture, and then adding the silane, metal ester and optional promoter immediately before placing in a container protected from moisture.

The compositions of the present invention are particularly suitable for filling and sealing applications where excellent adhesion to a variety of substrates is important.

For example, the compositions are useful for household and industrial caulks and seals such as buildings, factories, automobiles, and substrates such as stone, glass, plastic, metal, wood, and the like.

The compositions of the present invention are suitable for use with sensitive J! metals such as copper and brass. Little or no tendency to corrode the board. The compositions are also effective in having excellent application speeds, making them easily suitable for application by conventional caulking under normal conditions.

The following examples are intended to illustrate the invention and are not intended to limit it.

Example 1 A substrate formulation was prepared containing the following ingredients (parts by weight): Polydimethylsiloxane with silanol chain end groups (
Viscosity 25,000 cp) 100 parts stearic acid treated calcium carbonate...filler
100 parts Dimethylsiloxy-diphenylsiloxy copolymer solution having methoxy chain end groups (diphenylsiloxy content 30 mol% diviscosity 50 cp)...Thixotropic agent A catalyst mixture containing 5 parts or less of components was prepared (parts by weight) Methyltrimethoxysilane...Crosslinking agent 0.5 parts 1
．． 3-Dioxypropanethane-bis1ditylacetoacetate...catalyst 1.8 parts 1.3.5-tris-
Trimethoxysilylpropyl isocyanurate...
0.75 parts of adhesion promoter 100 parts of the substrate formulation and 3.05 parts of the catalyst mixture were mixed in the absence of air and atmospheric moisture and packed into 6 oz. polyethylene tubing.

The material was allowed to stand for 30 hours to reach chemical equilibrium. Test sheets were then made and heated to a temperature of 77 ± 2″F and 5
Cured for 7 days at 0±5% relative humidity. The following test results were obtained.

Shore A hardness: 17 Tensile strength: psi 85 Elongation 2%
1650 Coating speed 2 g/min 170 Rheological properties Self-fluidity Example 2 A substrate formulation was prepared containing the following ingredients (parts by weight):

Polydimethylsiloxane with silanol chain end groups (viscosity 25,000cp) 100 parts Hexamethylcyclotrisiloxane-treated fumed silica...Filler (specific surface area approx. 200g/g>1
0 parts stearic acid treated calcium carbonate... filler
Dimethylsiloxy-diphenylsiloxy copolymer liquid having 125 parts methoxy chain end group (diphenylsiloxy content 30 mol%: viscosity 5
0 cp 5 parts Polydimethylsiloxane fluid of 20 cp viscosity with trimethylsilyl chain end groups 20 parts A catalyst mixture was prepared as in Example 1 and 3.05 coulometric parts thereof were mixed with 100 parts by weight of the substrate formulation.

After reaching chemical equilibrium and curing as in Example 1, a rubber material was obtained having the following properties.

Shore A hardness 24 tensile strength; psi 190 elongation
990 Tear strength; lb/inch 45 knots () (n
otty) Adhesion-free time 3.5 hours (fingertip) Application speed 2 g/min 205 Flow 2 inches 0.12 Twirling time 30 minutes Specific gravity
1.42 The self-bonding adhesion of the composition was determined for Example 2 using an adhesive layer thickness of 8 inches per part.

Substrate Value Adhesive Failure % Polycarbonate: lb/inch 45-55 100 Polyacrylate / /l /
/P V Ctt // //Polystyrene l/ II I/Stainless steel The underwater adhesion after 43 days is as follows.

Substrate Values % Adhesive Failure Stainless Steel 2 Bond/inch 50 100 Polyacrylate 50 100 Example 3 A substrate formulation was prepared containing the following ingredients (parts by weight).

Polydimethylsiloxane having silanol chain end groups (viscosity 105.000 cp) 100 parts Octamethylcyclotetrasiloxane treated fumed silica...Filler (specific surface area approximately 200 I/g) 12
．． 5 parts stearic acid treated calcium carbonate... filler
Dimethylsiloxy-diphenylsiloxy copolymer liquid with 125 parts methoxy chain end group (diphenylsiloxy content 30 mol%, viscosity 50 cp) Polydimethylsiloxane liquid with viscosity 50 cp having 5 parts trimethylsilyl chain end group Contains up to 40 parts A catalyst mixture was prepared (parts by weight).

Methyltrimethoxysilane 1.5 parts 1.3
-Dioxypropanethane-bis-ethyl acetoacetate...Catalyst 1.8 parts 1.3.5-)Lis-
Trimethoxysilylpropyl isocyanurate)
0.75 parts 100 parts of the substrate formulation and 4.05 parts of the catalyst mixture were mixed in the absence of air and atmospheric moisture. The anhydrous material was chemically equilibrated, cured and tested as in Example 1. The following results were obtained.

Shore A Hardness 24 Tensile Strength: psi 230 Elongation: %
840 application speed: g/min
222 rheological properties
Non-sagging tack-free time 7 hours This composition is particularly good in its self-bonding and adhesive properties.

Example 4 A matrix formulation was prepared containing the following ingredients (parts by weight):

Polydimethylsiloxane having silanol chain end groups (viscosity 25,000 cps) 100 parts Octamethylcyclotetrasiloxane treated fumed silica Filler (specific surface area 20
0rrr/g) 10 parts Stearic acid treated calcium carbonate...filler 85 parts Silanol-containing polymethylsiloxane liquid (approximately trimethoxyloxy content 5 mol%, methylsiloxy content 20 mol%, dimethylsiloxy content 75 mol) %, a silanol content of 0.5% by weight, a viscosity of 25 cp, and a catalyst solution containing 15 parts or less (parts by weight).

Methyltrimethoxysilane 0.5 part 1.3-
Dioxypropanethane-bis-dityl acetoacetate (catalyst) 1.8 parts 1.3.5-) Lis-trimethoxysilylpropyl isocyanurate 0.75 parts The above substrates were formulated in the absence of air and atmospheric moisture. 100 parts of the product were mixed with 3.05 parts of the catalyst solution. The anhydrous material was allowed to stand for 3 days and then cured before being tested as described in Example 1.

The following test results were obtained.

Shore A Hardness 25 Tensile Strength: psl 155 Elongation, %
860 application speed, 27 minutes
115 Rheological properties
Non-sagging Non-stick time 3 hours Peel adhesion from stainless steel, bonds/inch 55 Example 5 1,3-dioxypropane instead of 1,3-dioxypropanethane-bis-dithyl acetoacetate as catalyst Example 1 using titanium-bis-acetylacetonate
The procedure was repeated. Almost identical results were obtained.

Example 6 1,3-dioxypropanethane- instead of 1,3-dioxypropanethane-bis-ethyl acetoacetate
The procedure of Example 2 was repeated using bis-acetylacetonate as the catalyst. Almost identical results were obtained.

Example 7 1,3-dioxypropanethane- instead of 1,3-dioxypropanethane-bis-ethyl acetoacetate
The procedure of Example 1 was repeated using bis-pentadecyl acetoacetate. Almost identical results were obtained.

Example 8 The procedure of Example 1 was repeated using the following catalyst in place of 1.3-dioxypropanethane-bis-ethylacetoacetate. Almost identical results were obtained.

Example 9 The procedure of Example 2 was repeated using diisopropoxytitanium-bis-ditylacetoacetate in place of 1.3-dioxypropanethane-bis-ditylacetoacetate. In this case too, properties of low modulus were obtained, but the elongation was low and the tensile strength and peel adhesion values were substantially reduced.

Shisia A hardness 17 tensile strength ps
i 43 elongation %
805 Flow In. 0.28 Peel Adhesion Bond/in. Stainless Steel 17" Polyacrylate 1588 100% cohesive failure occurred.

The following example illustrates the case where the crosslinking agent is used in a higher proportion than the titanium chelate, ie, the ratio of (c) to (b) is 0.865.

Example 10 A matrix formulation was prepared containing the following ingredients (parts by weight):

Polydimethylsiloxane with silanol chain end groups (viscosity 25,000 cp) 100 parts hexamethylcyclotrisiloxane-treated fumed silica...filler (specific surface area approximately 200 g/g) 13 parts stearic acid-treated calcium carbonate...・Filler: 85 parts Silanol-containing polymethylsiloxane liquid (roughly, trinotylsiloxy content 5 mol%, methylsiloxy content 20 mol%, dimethylsiloxy content 75 mol%, silanol content 0.5% by weight, viscosity 25 cp) 15 parts Polydimethylsiloxane liquid having trimethylsilyl chain end groups (viscosity 50 cp) A catalyst solution containing 25 parts or less of components was prepared (parts by weight).

Methyltrimethoxysilane 1.5 parts 1.3-dioxypropanethane-bis-ethylacetoacetate (catalyst) 1.3 parts 1.3.5-tris-trimethoxysilylpropyl isocyanurate 0.75 parts Air and atmosphere 100 parts of this substrate formulation was mixed with 3.55 parts of catalyst solution without any moisture present. The anhydrous material was allowed to stand for 30 hours and then cured before being tested as described in Example 1.

The above example may be modified in other cases to obtain tacky, low modulus, one-package 12RTV compositions within the scope of the present invention.

For example, instead of polydimethylsiloxane with silanol chain end groups having a viscosity of 25,000 and 105.00 Gcp, a polydimethylsiloxane with silanol chain end groups having a viscosity of 190,000 cp can be used.

When dioxypropanethane-bis-ethylacetoacetate is used as a catalyst, the repeating units in the polydimethylsiloxane chain range from 370 to 1,350. Further, in the case of dioxypropanethane-bis-acetylacetonate, it is preferable that the average number of repeating units in the polydimethylsiloxane chain having silanol chain end groups is 300 to 5,260. 1.3.5-tris-trimethoxysilylpropylisocyanurate instead of bis-1,3-
) Rimethoxysilylbropylisocyanurate or acetonitrile can be used, or such promoters can be omitted altogether. Corresponding iron, germanium, and zirconium analogs can also be used in place of titanium ester catalysts.

Example 11 The particular preference for a weight ratio of components (C) to (b) of at least 1 is illustrated below.

Methyltrimethoxysilane 0.5 0.5 1.5 3.9 2.32 1.3-dioxypropanthanitan-bisethylacetoacetate 1.8 1.3 1.3 1.3 0.75 (c) / (b) 3.8 2.8 0.87 0.83 0.82 1.15-tris-trimethoxysilylpropylisocyanurate 0.75 0.75 0.75 0.75 0.75 of substrate formulation Composition Polydimethylsiloxane having silanol chain end groups (viscosity 25,000 cps) ■OO Dimethylsiloxy-diphenylsiloxy copolymer liquid having methoxy chain end groups (diphenylsiloxy content 30
Mol%: viscosity 50 cps) Octamethylcyclotetrasiloxane treated fumed silica (specific surface area approximately 200 g/g) Stearic acid treated calcium carbonate Polydimethylsiloxane liquid with viscosity 20 cps having trimethylsilyl chain end groups Non-stick time (hours) Sag, inch application speed 27 minutes Shore A hardness (1) Tensile strength (1) (psi) Elongation (1), % Peel adhesion (2) Bond/inch (% vertical tube failure) 1G Stainless steel polyacrylate 40 (10G) 45 (100) 35 (10)
10(0) 8(Notes: (1) ASTM test sheets were cured for 72 hours at 77″F and 750% relative humidity.

(2) Peel Adhesion Test specimens were cured for 10 days at 77”F 150% relative humidity.

Looking at the (c)/(b) weight ratio of the above compositions, the (c)/(b) weight ratio of compositions 3 to 5 is 0.87, respectively.
．． 0.33 and 0.32, which are less than 1, whereas the (C)/(b) weight ratios of compositions 1 and 2 are 3.6 and 2.6, respectively, which are more than 1. I'm here.

and (c)/(b) weight ratio is 0°87 of composition 3.
By moving from Composition 2 to 2.6, that is, by at least 1, the tensile strength decreases rapidly, the elongation increases significantly, and the peel adhesion is 100% due to adhesive failure. Masu.

Therefore, from the experimental data of this Example 11, (C)/(b)
A fluid composition particularly suitable for caulking applications that can be cured into a self-bonding elastic solid with low tensile strength and very high elongation exhibiting 100% cohesive failure by having a weight ratio of at least 1. is clearly provided.

Claims (1)

[Claims] 1. Formula (a) ▲ Numerical formulas, chemical formulas, tables, etc. Polydiorganosiloxanes containing silanol chain end groups of up to 8 atoms and n averaging from about 10 to 15,000
0 parts by weight, (b) formula R^2_mSi(OR^3)_4_-_m (in the above formula, R^2 and R^3 have the meanings defined above for R and R^1, and m is It has a value of 0 to 3, with an average value of 0 to 1, based on the total amount of silane in the composition.
99) is a silane crosslinking agent represented by 0.01 to 5.
0 parts by weight, and (c) a partially chelated ester of a lower aliphatic alcohol and a β-dicarbonyl compound with a silanol-reactive organometallic ester compound consisting of a metal other than silicon, or a partial hydration of such a compound. A compound which is a decomposition product and has at least one hydrocarbonoxy group or substituted hydrocarbonoxy group bonded to a metal atom via an M-O-C bond (M is the above metal) 0.1 to 10 parts by weight, the weight ratio of components (c) to (b) always being at least 0.5 and less than 1; stable under substantially anhydrous conditions and self-associating in the presence of moisture; A fluid composition that can be cured into a resilient, elastic solid. 2. The composition according to claim 1, wherein the total number of moles of the silane crosslinking agent (b) is smaller than the total number of moles of chain-end silanol groups in the polydiorganosiloxane component (a). 3. The total number of moles of silanol-reactive ester bonds in the organometallic ester compound (c) is equal to or greater than the total number of moles of chain-end silanol groups in the polydiorganosiloxane component (a). Composition according to item 1. 4. The total number of moles of silanol-reactive ester bonds in the organometallic ester compound (c) is equal to or greater than the total number of moles of chain-end silanol groups in the polydiorganosiloxane component (a). Composition according to item 2. 5. The viscosity of component (a) is 2,000 to 1,00 at 25°C
A composition according to claim 1, wherein the composition is within the range of 0,000 cp. 6. The viscosity of component (a) is 20,000 to 200 at 25°C
,000 cp. 7. The composition according to claim 1, wherein in component (a), at least 50% of the total number of R and R^1 groups are alkyl groups, and the remaining groups are all aryl groups. . 8. The composition according to claim 7, wherein the alkyl group is a methyl group and any remaining aryl groups are phenyl groups. 9. In component (b), at least 50% of the total number of R^2 and R^3 groups are alkyl groups, any remaining groups are aryl groups, and m is 1. Composition according to item 1. 10. The composition according to claim 9, wherein the alkyl group is a methyl group and any remaining aryl groups are phenyl groups. 11. In the organometallic ester component (c), the metal M is lead, tin, zirconium, antimony, iron, cadmium, barium, calcium, titanium, bismuth, manganese, zinc, chromium, cobalt, nickel, aluminum, A composition according to claim 1, wherein the composition is selected from gallium and germanium. 12. The composition according to claim 11, wherein the metal M in the organometallic ester component (c) is titanium. 13. The composition of claim 1, further comprising from about 10 to about 100 parts by weight of filler per 100 parts of polydiorganosiloxane containing silanol chain end groups. 14. Claim 13, wherein the filler is calcium carbonate or a mixture of fumed silica and calcium carbonate.
Compositions as described in Section. 15. The composition of claim 1, further comprising 0.2 to 2 parts of adhesion promoter per 100 parts of polydiorganosiloxane having silanol chain end groups. 16. The adhesion promoter has a formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (G is the same as R^1^0 defined later, or (R^1^1
O)_3_-_b-R^1^0_b-Si-R^9 groups,
styryl, vinyl, allyl, chloroallyl or chlorohexyl, R^3 is a divalent group selected from alkylene-arylene, alkylene, cycloxyene, and halogen substituted products of such divalent groups, and R^1^0 is a group of up to 8 carbon atoms selected from hydrocarbyl and halogenated hydrocarbyl, and R^1^1 is R^1
16. A composition according to claim 15, wherein ^0 is a radical of the type defined for ^0 or cyano-lower alkyl, and b is from 0 to 3. 17. The composition according to claim 15, wherein the adhesion promoter is 1,3,5-tris-trimethoxysilylpropyl isocyanurate. 18. Claim 15, wherein the adhesion promoter is bis-1,3-trimethoxysilylpropyl isocyanurate.
Compositions as described in Section. 19. The composition of claim 1, further comprising from about 0.3 to about 20 parts by weight of a polydiorganosiloxane viscosity reducer per 100 parts of polydiorganosiloxane component (a) having silanol chain end groups. . 20. The viscosity reducing agent has the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, R^1^2 and R^1^3 are carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, and cyano lower alkyl, respectively Up to 8 organic groups, where R^1^4 and R^1^5 are each hydrogen or R^1^
2 and R^1^3, and x has a value from 2 to 46. 21, at least 5 of the total number of R^1^2 and R^1^3
21. The composition of claim 20, wherein 0% are alkyl groups and all remaining groups are aryl groups. 22. The composition according to claim 21, wherein the alkyl group is methyl and the remaining aryl groups are phenyl. 23. In the viscosity reducing agent, R^1^4 and R^1^5
is hydrogen or methyl, R^1^2 and R^1^3 are methyl or methyl and phenyl, in the latter case the ratio of methyl to phenyl is about 70:30, and x is an integer from 3 to 50 A composition according to claim 20. 24, Formula (a) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the above formula, R and R^1 are each an organic compound with up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, and cyano lower alkyl) 100 parts by weight of a polydiorganosiloxane having a silanol chain end group (n is 10 to 15,000 on average), (b) formula R^2_mSi(OR^3)_4_-_m (in the above formula, R^2 and R^3 have the meanings defined above for R and R^1, m is from 0 to 3 and has an average value from 0 to 1.99 based on the total amount of silane in the composition. )
0.01 to 5.0 parts by weight of a silane crosslinking agent, and (c) formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, R^4 is hydrogen or an organic group of up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl and carboxyalkyl; R^5 is a group of up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl and cyano lower alkyl; R^6 is the same group as R^4, and a group selected from halo, cyano, nitro, carboxyester or acyl, and hydrocarbyl substituted with such halo, cyano, nitro, carboxyester or acyl, and R^4 and The total number of carbon atoms in the alkanedioxy group substituted with R^6 does not exceed about 18, and R^7 is an organic group of up to 8 carbon atoms selected from hydrogen or hydrocarbyl, halogenated hydrocarbyl, or acyl. a cyclic hydrocarbon substituent of up to about 12 carbon atoms or one or more chloro, nitro, forming a cyclic hydrocarbon substituent substituted with acyl, cyano or carboxy ester, X is hydrocarbyl, halogenated hydrocarbyl, cyanoalkyl,
Alkoxy, halogenated alkoxy, cyanoalkoxy, amino or formula (C_qH_2_qO)_vR (however,
q is 2-4, v is 1-20 and R is hydrocarbyl,
2 carbon atoms selected from ether and polyether groups (which are organic groups of up to 8 carbon atoms selected from halogenated hydrocarbyl and cyano-lower alkyl)
up to 0 groups, a is an integer up to 0 or 8,
When a is 0, there are ▲mathematical formulas, chemical formulas, tables, etc.▼The groups form a ring and are bonded to each other, and R^8 is up to 8 carbon atoms selected from hydrocarbyl, halogenated hydrocarbyl, and cyano lower alkyl. The composition consists of 0.1 to 10 parts by weight of a titanium chelate catalyst represented by
) is always at least 0.5 and less than 1, the fluid composition being stable under substantially anhydrous conditions and capable of hardening in the presence of moisture to a self-assembling elastic solid. 25. The composition according to claim 24, wherein the component (c) has the formula ▲A mathematical formula, a chemical formula, a table, etc.▼. 26, R^2 and R^3 in component (b) are alkyl,
R^4 and R^6 in component (c) are hydrogen, and R^
25. The composition of claim 24, wherein 5 is alkyl. 27, R^2 and R^3 in component (b) are methyl, R^5 in component (c) is methyl, X is -OC_1_5
25. The composition according to claim 24, wherein H_3_1 and a is 1. 28. The composition according to claim 27, wherein R^4 and R^6 in component (c) are each hydrogen. 29, R^2 and R^3 in component (b) are methyl, R^5 and X in component (c) are methyl and R
27. The composition of claim 26, wherein ^4 and R^6 are hydrogen. 30. Component (a) is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, n is about 300 to about 5260), and component (b) is (CH_3)Si(OCH_3)_3,
and the composition according to claim 24, wherein component (c) is ▲a mathematical formula, a chemical formula, a table, etc.▼. 31. Component (a) is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, n is about 370 to about 1,350), and the component (
25. The composition according to claim 24, wherein b) is CH_3Si(OCH_3)_3, and component (c) is ▲a mathematical formula, a chemical formula, a table, etc.▼. 32. In component (c), a is 0 or 1, and R^
25. The composition of claim 24, wherein 4 and R^6 are hydrogen or methyl.