JPH04335066A - Additive for improving the low modulus of room temperature curing silicone composition - Google Patents

Abstract

PURPOSE: To provide a one-pack type room temp. curing silicone compsn. which has improved low modulus characteristics and good storage stability and contains no scavenger.

CONSTITUTION: A room temp. curing organopolysiloxane compsn. contg. a polyalkoxy-terminated organopolysiloxane, a diorganotinβ-diketoate condensation catalyst and a low modulus improved additive being a low viscosity monoalkoxy-terminated polydiorganosiloxane and having good storage stability, is provided. As a pref. embodiment for practising in use, a polyalkoxysilane crosslinking agent and an adhesion accelerator, pref. a two component adhesion accelerator system contg. a cyano-functional polyalkoxysilane and an isocyanate- functional alkoxysilane are incorporated.

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to one-part, scavenger-free, room temperature curable silicone compositions. In particular, the present invention relates to additives that improve the low modulus properties of one-part, scavenger-free, room temperature curable silicone compositions.

0002

BACKGROUND OF THE INVENTION One-part, alkoxy-type curative cured room temperature curable (RTV) silicone rubber compositions containing low modulus improving additives are known in the art. For examples of such silicone compositions, see US Pat. No. 4,323,489, which uses difunctional acetamide coupling agents as low modulus improvers.

The low modulus properties of the one-component, scavenger-free RTV silicone rubber composition of the present invention are achieved by the presence in the composition of a low molecular weight, monoalkoxy-terminated diorganopolysiloxane, which will be described in detail below. This is based on the knowledge that it can be improved.

The use of monoalkoxy-terminated diorganopolysiloxanes in one-part, RTV silicone rubber compositions cured by alkoxy-type curatives is known in the art. Examples of such techniques are described in U.S. Pat. No. 4,593,085, U.S. Pat. No. 4,670,532, and U.S. Pat.

According to the Lucas et al. patent, the monoalkoxy-terminated diorganopolysiloxane is present as an undesirable contaminant and not as a low modulus improver. Furthermore, Lu
The monoalkoxy-terminated diorganopolysiloxane used in the RTV composition of Cas et al.
It has a viscosity of between 1,000,000 and 1,000,000 centipoise.

The present invention provides that monoalkoxy-terminated diorganopolysiloxanes having a viscosity of from about 5 to about 95 centipoise at 25°C have a low modulus of one-part RTV silicone compositions prepared using monoalkoxy-terminated polydiorganosiloxanes. This is based on the knowledge that it enhances the characteristics.

[0007]

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a storage stable, scavenger-free, one-part RTV silicone composition with improved low modulus properties.

This and other objects are achieved by the present invention.

The present invention provides the following components: (A) having a viscosity of about 100 to about 1,000,000 centipoise at 25° C., each silicon atom at the end of the polymer chain being terminally substituted with at least two alkoxy groups; 100 parts of a polyalkoxy-terminated polydiorganosiloxane having as C1-15 monovalent hydrocarbon groups; (B) only one alkoxy group on each terminal silicon atom in the polymer chain; ( C) About 0 to about 40 parts of reinforcing filler: (D) General formula:

0010

[Formula 8] (wherein, R5 is a group selected from a C1-18 monovalent hydrocarbon group and a substituted hydrocarbon group, and R6, R7
and R8 is hydrogen, R5, OR5, -Si(R5
)3, -OSi(R5)3, which is a monovalent group which may be the same or different selected from the group consisting of aryl, acyl and nitrile groups); E) about 0 to about 5 parts of a β-diketone having the general formula: (wherein R6, R7 and R8 are as defined above);
F) Formula: (wherein R3 and R4 are C1-8 monovalent hydrocarbon groups, t is 0 to 3, and Z is further ether, epoxy, isocyanato, cyano, isocyanurate, acryloxy (G) General formula:

[0011]

embedded image (wherein each R3 and R4 is independently 1 to about 18
R5 is a C2-12 divalent hydrocarbon group, and t is a number ranging from about 0 to about 3). Auxiliary adhesion promoter cyanofunctional polyalkoxysilane with 0
0 to 2 parts; and (H) crosslinking agent polyalkoxysilane
from about 10 parts to about 10 parts;
A one-component room temperature curable silicone composition is provided.

0012

DETAILED DISCLOSURE Component (A) of the compositions of the present invention has at least two alkoxy groups as terminal substituents at each end of the polymer chain and has a molecular weight of from about 100 to about 1,000 at 25°C.
The diorganopolysiloxane polymer has a viscosity in the range of 0.000 centipoise, preferably in the range of about 5000 to about 200,000 centipoise. The organo groups of the polymer are C1-15 monovalent hydrocarbon groups.

Preferably, the polymer constituting component (A) has the general formula (I)

[0014]

embedded image (wherein each R and R2 are independently substituted or unsubstituted C
1-15 monovalent hydrocarbon group; R1 is an alkyl group,
C1-8 aliphatic organic group or C7-15 aralkyl group selected from alkyl ether group, alkyl ester group, alkyl ketone group, alkyl cyano group; n is about 50
and a is an integer of 0 or 1).

In formula (I), R is preferably C1-
13 monovalent hydrocarbon groups, halogenated monovalent hydrocarbon groups and cyanoalkyl groups; R1 is preferably C1-8
an alkyl group or a C7-13 aralkyl group; and R2 is preferably a methyl, phenyl or vinyl group. Most preferably R, R1 and R2 are each a methyl group.

The terminal silicon atoms in the polymer of component (A) must have at least two alkoxy substituents and may have three alkoxy groups according to the definition of formula (I) above.

The polyalkoxy-terminated organopolysiloxanes of formula (I) can be prepared in various ways. An example of such a process involves reacting a polyalkoxysilane with a silanol-terminated polydiorganosiloxane in the presence of an amino catalyst, as described in Cooper et al., US Pat. No. 3,542,9.
It is described in the specification of No. 01.

The polymer of formula (I) is preferably Chung
No. 4,515,932. According to the method of Chung, the polymer has a molecular weight of 100 to 1,000 at 25°C.
A silanol-terminated diorganopolysiloxane having a viscosity in the range of 0,000 centipoise and in which the organo group is a monovalent hydrocarbon is cross-linked with a polyalkoxysilane of the formula: where R1, R2 and a are as defined above. It is produced by reacting with an agent.

The silanol terminated polymer used in the preparation of the polymer of formula (I) by the method of Chung has the formula:

0
020]

embedded image wherein R and n are as defined above.

The end-coupling reaction for preparing the polymer of formula (I) according to the method of Chung involves combining the polyalkoxysilane crosslinker with one or more silanol-terminated diorganopolysiloxane polymers using a Bronsted acid, It is carried out by mixing in the presence of an end coupling catalyst selected from Lewis acids, stearic acid treated calcium carbonate and amines and mixtures thereof. The amine used here can be primary, secondary or tertiary.
Any grade amine may be used. The more basic the amine, the better it is as a catalyst. The most preferred catalyst is one of the acids listed above, and most preferably a combination of one of such acids and an amine. After the end coupling is completed, a silazane (eg, hexamethyldisilazane) is added to deactivate the amine salt catalyst to obtain a storage-stable polymer. More detailed information on such catalysts and end-coupling reactions can be found in Chung, cited above.
No. 4,515,932.

Component (B) has only one alkoxy group on each terminal silicon atom in the polymer chain and has a molecular weight of about 5 to about 95 centipoise, preferably about 10 to about 80 centipoise, at 25°C.
centipoise, most preferably about 40 to about 60 centipoise
It is a polydiorganosiloxane polymer having a viscosity in the centipoise range and in which the organo group is a monovalent C1-15 hydrocarbon group.

The monoalkoxy-terminated polymer preferably has the formula (II)

[0024]

embedded image where R, R1 and R2 are as defined above, and m is a number ranging from about 1 to about 40, preferably from about 5 to about 30, most preferably from about 10 to about 20. ).

The polymer of formula (II) is a silanol-terminated diorganopolysiloxane polymer having a viscosity in the range of about 100 to about 1,000,000 centipoise at 25°C and a compound of the formula: and s is an integer of 2) in the presence of an end-coupling catalyst.

The silanol-terminated polymer used to prepare the polymer of formula (II) is the same as the silanol-terminated polymer used to prepare the polymer of formula (I).

The terminal coupling reaction is carried out in the same manner as described above for the preparation of the polymer of formula (I), ie, the dialkoxysilane and the silanol-terminated diorganopolysiloxane polymer are combined with a Bronsted acid, Lewis acid,
This is carried out by mixing in the presence of an end-coupling catalyst selected from the group consisting of stearic acid treated calcium carbonate and amines and mixtures thereof.

The monoalkoxy-terminated polydiorganosiloxane of formula (II) is present in the RTV compositions of the present invention in an amount of from about 1 to about 40 parts, preferably from about 10 to about 30 parts, per 100 parts of polyalkoxy-terminated polydiorganosiloxane (A).
parts, more preferably in an amount ranging from about 15 to about 25 parts.

Preferably, the RTV composition of the present invention further contains a filler (C). For example, titanium dioxide, zirconium silicate, silica aerogel, iron oxide, diatomaceous earth,
Various fillers may be incorporated into the compositions of the present invention, such as fumed silica, carbon black, precipitated silica, glass fibers, polyvinyl chloride, quartz powder, calcium carbonate, and the like. Preferred fillers for use in the compositions of this invention are reinforcing fillers, most preferably fumed silica fillers.

The amount of filler used can vary within wide limits depending on the intended use. For example, in certain applications as sealants, the room temperature curable compositions of the present invention may be used without fillers. When using the room temperature curable compositions of the invention for other applications, for example in the production of binders, polyalkoxy-terminated polydiorganosiloxanes (
A) Higher amounts of filler can be used, such as 700 parts per 100 parts by weight or more.

The compositions of the invention may also be used as construction sealants and caulking compounds. The exact amount of filler will therefore depend on factors such as the application for which the composition is intended and the type of filler used. Preferably, organopolysiloxane (A)1
from about 5 to about 300 parts per 00 parts of filler are used;
The filler may contain up to about 40 parts, preferably from about 5 to about 40 parts, of reinforcing filler, such as fumed silica filler.

It is often advantageous to pre-treat the silica filler with an activator such as octamethylcyclotetrasiloxane.

Component (D) has the general formula (III)

003
4]

embedded image (wherein R5 is a group selected from C1-18 monovalent hydrocarbon groups and substituted hydrocarbon groups; and R6, R7
and R8 is hydrogen, R5, OR5, -Si(R5
)3, -OSi(R5)3, which may be the same or different monovalent groups selected from the group consisting of aryl, acyl and nitrile groups), is a diorganotin-bis-diketonate condensation catalyst.

Examples of groups included within the scope of R5 in formula (III) are C6-13 aryl groups and halogenated aryl groups, such as phenyl, tolyl, chlorophenyl, naphthyl groups; C1-18 aliphatic, alicyclic groups. group groups and their halogenated derivative groups, such as cyclohexyl,
Cyclobutyl; alkyl and alkenyl groups, such as methyl, ethyl, propyl, chloropropyl, butyl, pentyl, hexyl, heptyl, octyl, vinyl, allyl and trifluoropropyl groups.

Representative examples of tin condensation catalysts falling within the scope of formula (III) include the following compounds.

Di(n-butyl)tin bis(acetylacetonate); Di(n-butyl)tin bis(benzoylacetonate); Di(ethyl)tin bis(lauroylacetonate); Di(methyl)tin bis( pivaloylacetonate)
; di(n-octyl)tin bis(acetylacetonate)
; di(n-propyl)tin bis(1,1,1-trifluoroacetylacetonate); di(n-butyl)tin bis(
ethyl acetoacetate); and di(n-butyl)tin (
acetylacetonate) (ethylacetoacetate).

The preferred tin catalyst for use in the present invention is di(n-butyl)tin bis(acetylacetonate).

The effective amount of catalyst is typically about 0 per 100 parts of polyalkoxy-terminated polydiorganosiloxane (A).
．． 0.01 to about 2.0 parts, preferably about 0.1 to about 1.0 parts, most preferably about 0.2 to about 0.4 parts.
Within the scope of this section.

In a preferred embodiment, R of the present invention
The TV composition further contains a β-diketone (component (D)) capable of chelating with the tin condensation catalyst of formula (III). Beta-diketones, hereinafter referred to as "chelating ligands", have been found to impart improved storage stability to RTV compositions when used in effective amounts. Chelating ligands useful in the present invention have the general formula (IV), where R6, R7 and R8 are as defined above.

From the standpoint of cost and availability, the preferred chelating ligand is 2,4-pentanedione. However, the U.S. Environmental Protection Agency recently promulgated a Significant New Use Rule.
Rule (SNUR) includes 2,4-pentanedione among substances classified as potential neurotoxins, mutagens, and developmental toxins by inhalation. This SNUR essentially prohibits the use of 2,4-pentanedione in all new consumer products, thus severely limiting the marketability of RTV sealants containing 2,4-pentanedione. Ru. Other relatively non-toxic β-diketones can be used in place of 2,4-pentanedione. Such non-toxic β
- Examples of diketones include the following compounds.

2,2,6,6-tetramethyl-3,5-
Heptanedione; 1,1,1-trifluoro-2,4-
Pentanedione; 1-phenyl-1,3-butanedione; 2,4-hexanedione; 5,7-nonanedione.

The most preferred non-toxic β-diketone is 2
, 4-hexanedione.

When a chelating ligand is used, it typically contains about 0.1 to about 1.0 parts, preferably about 0.2 to about 0 parts per 100 parts of polyalkoxy-terminated polydiorganosiloxane (A). RT of the present invention in an amount within the range of .8 parts, most preferably from about 0.3 to about 0.5 parts.
V composition.

The RTV compositions of the present invention optionally have the general formula (
V) (wherein R3 and R4 are C1-8 monovalent hydrocarbon groups, t is 0 to 3, and Z is further selected from ether, epoxy, isocyanato, cyano, isocyanurate, acryloxy and acyloxy groups) The adhesion promoter organofunctional polyalkoxysilane (F) has a saturated, unsaturated or aromatic hydrocarbon group substituted with a functional group selected from the group consisting of:

Formula (V) above suitable for use in the present invention
Adhesion promoter compounds within the scope of and methods of making them are described, for example, in U.S. Pat. No. 4,483, incorporated herein by reference.
, 973 and specification No. 4,528,353 (Lu
cas et al.).

Preferred adhesion promoters are isocyanato-functional polyalkoxysilanes.

Isocyanato-functional polyalkoxysilanes suitable for use in the present invention have the general formula (VII)

[0049]

embedded image (wherein, G is a group selected from R9 group, a group of the formula: styryl, vinyl, allyl, chlorallyl, and cyclohexenyl group, and R11 is a group of C1
-8 is a monovalent hydrocarbon group or a cyanoalkyl group, R
12 is a C1-8 monovalent hydrocarbon group or a cyanoalkyl group, and R13 is a C2 selected from an alkylene arylene group, an alkylene group, a cycloalkylene group, a halogenated alkylene arylene group, a halogenated alkylene group, and a halogenated cycloalkylene group. -12 divalent hydrocarbon group and b is 0 to 3).

More detailed information on such compounds can be found in US Pat. No. 4,100, incorporated herein by reference.
No. 129 (Beers), No. 3,821,218 (Berger), No. 4,483,973 (Luc
as et al.) and No. 4,528,353 (Lucas et al.) and No. 4,528,353 (Lucas et al.
et al.) as disclosed in the specification.

The most preferred adhesion promoter within formula (VII) is 1,3,5-trismethoxysilylpropylisocyanurate. This compound uses the corresponding alkoxyhydrogenated silane and reacts it with an unsaturated isocyanurate or cyanurate in the presence of a platinum catalyst to form a hydrogen atom on the unsaturated group, such as the allyl group of the isocyanurate nucleus. It can be manufactured by adding (hydride). group R1
4 may be selected from any divalent hydrocarbon group which may be substituted or unsubstituted so long as it does not interfere with the adhesion promoting activity of the compound. It should be noted that compounds with highly complex structures are undesirable as they are more difficult to produce and obtain, and therefore more expensive. The above formula (V
Other specific compounds within the scope of II) are:

Bis-1,3-trimethoxysilylpropylisocyanurate; 1,3,5-tristrimethoxysilylethylisocyanurate; 1,3,5-trismethyldimethoxysilylpropylisocyanurate; 1,
3,5-trismethyldiethoxysilylpropyl isocyanurate.

The isocyanato-functional alkoxysilane adhesion promoter is present in the RTV compositions of the present invention in an amount of about 0 per 100 parts of polyalkoxy-functional polydiorganosiloxane (A).
from about 2.0 parts by weight, preferably from about 0.1 to about 1
．． 0 parts by weight, most preferably from about 0.3 to about 0.0 parts by weight.
It may be present in an amount within the range of 7 parts by weight.

Preferably, the RTV compositions of the invention may further contain cyanofunctional polyalkoxysilanes (G) as auxiliary adhesion promoters. Cyanofunctional polyalkoxysilanes suitable for use in the present invention have the general formula (VIII
)

[0055]

embedded image (wherein each R3 and R4 is independently 1 to about 18
R5 is a C2-12 divalent hydrocarbon group, and t is a number ranging from about 0 to about 3). may have.

In the compound of formula (VIII), R3
and R4 is an alkyl group, such as methyl, ethyl, propyl, etc.; an alkenyl group, such as vinyl, allyl, etc.;
It can be cycloalkyl groups, such as cyclohexyl, cycloheptyl, etc.; mononuclear aryl groups, such as methylphenyl; and fluoroalkyl groups, such as 3,3,3-trifluoropropyl. Preferably R3
and R4 are selected from methyl and ethyl groups, most preferably both are methyl groups. R5 is preferably alkylene or arylene substituted or unsubstituted 2-12
, more preferably 2-8 carbon atoms.

A preferred specific compound within formula (VIII) above is γ-cyanopropyltrimethoxysilane. Other specific compounds include:

3-(cyanoethoxy)-3-methylbutenyltrimethoxysilane; β-cyanoethylmethyldimethoxysilane; β-cyanoethyltriethoxysilane;
β-cyanoethyltrimethoxysilane; 2-cyanoethylmethyldiethoxysilane; 3-cyanopropyltriethoxysilane; cyanopropylmethyldimethoxysilane; 1-cyanoethyltris(methoxyethoxy)silane.

Methods for preparing compounds within the scope of formula (VIII) are described in Lucas et al., US Pat. No. 4,483,973 and US Pat.
It is disclosed in the specification of No. These compounds are prepared by reacting a cyanated olefin with a trichlorohydrogenated silane in the presence of a platinum catalyst to produce the desired intermediate, which is then alkoxylated to produce the preferred γ-cyanopropyltrimethoxysilane. It can be manufactured by this method. Thus, one particular type of reaction may be, for example, the reaction of allyl cyanide with trichlorosilane. Reacting trichlorosilane with allyl cyanide in this reaction reduces the yield of the desired product when using the methoxylated product as an intermediate and subjecting it to a platinum-catalyzed addition reaction. This is because there is an inconvenience.

Preferred cyano-functional polyalkoxysilanes for use in the compositions of this invention are cyanoalkyltrialkoxysilanes, most preferably cyanoethyltrimethoxysilane.

The cyano-functional polyalkoxysilane is present in the compositions of the present invention in amounts from about 0 to about 5 parts, preferably from about 0.1 to about 1.0 parts, most preferably from about 0.1 to about 1.0 parts per 100 parts of polyalkoxy-terminated polydiorganosiloxane (A). Preferably about 0
．． Amounts ranging from 3 to about 0.7 parts may be used.

The RTV compositions of the present invention optionally contain a (H) polyalkoxysilane crosslinker. The crosslinking agent preferably has the general formula (IX), where R1, R2 and b are as defined above.

Representative compounds represented by formula (IX) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, tetraethoxysilane, and vinyltrimethoxysilane. Methyltrimethoxysilane is preferred.

The polyalkoxysilane crosslinking agent is R of the present invention.
from about 0 to about 20 parts by weight per 100 parts of polyalkoxy-functional polydiorganosiloxane (A) in the TV composition;
Preferably, it may be present in an amount ranging from about 0.1 to about 2.0 parts by weight, and most preferably from about 0.5 to about 1.0 parts by weight.

The compositions of the invention further comprise triorganosilyl-terminated diorganosilyl groups having a viscosity of 10 to 5000 centipoise at 25° C. and wherein the organo group is preferably a monovalent hydrocarbon group having from 1 to 8 carbon atoms. Polysiloxane (I) may be included in an amount of about 1 to about 50 parts by weight. Such linear diorganopolysiloxane polymers are useful as plasticizers. Preferably, such plasticizers do not contain silanol groups, but usually about 500 ppm.
Contains up to m silanol groups. Further, the organo substituent is methyl and the viscosity is 10 to 1 at 25°C.
Preferably, it is in the range of 0,000 centipoise.

Instead of or in addition to the plasticizers mentioned above,
The room-temperature curable compositions of the present invention may further contain 1 to 20 parts by weight of a liquid siloxane ("MDT" silicone fluid) containing a high proportion of trifunctional, tetrafunctional, or trifunctional and tetrafunctional siloxy units. It is desirable to contain Generally, such plasticizers include (i) monoalkylsiloxy units;
25-60 mol% of siloxy units or mixtures thereof, (
ii) 1-6 mol% trialkylsiloxy units and (i
ii) containing 34-74 mol% dialkylsiloxy units and containing about 0 silicon-bonded hydroxyl groups;
．． It contains 1 to about 2% by weight.

Other compounds, such as flame retardants such as platinum, may also be included in the compositions of the invention.

[0068] The RTV compositions of the present invention may be manufactured by methods known in the art. For example, the compositions of the present invention may be prepared by simultaneously mixing all the required ingredients together. However, the compositions of the present invention first precisely formulate a mixture of polyalkoxy-terminated polymer, cyano-functional polyalkoxysilane and filler, then cross-linker, tin catalyst, stabilizer/scavenger, adhesion promoter and It is preferably prepared by adding other ingredients, such as plasticizers, separately or together and then thoroughly mixing the resulting mixture under anhydrous conditions.

The RTV compositions of the present invention can be applied to a variety of substrates, particularly masonry substrates.
s) may be coated on. Examples of suitable supports include aluminum, glass, polyacrylate, polycarbonate, polyvinyl chloride and concrete.

[0070]

[Description of Examples] Next, the present invention will be further explained by Examples, but these Examples are merely for illustrating the present invention and are not intended to limit the present invention in any way. In the examples, all parts are by weight. Example 1 A methyldimethoxysilyl-terminated polydimethylsilicone polymer was prepared as follows. The following materials were mixed together.

Hydroxy-terminated polydimethylsilicone polymer having a viscosity of 110,000 centipoise at 25°C 100 parts Methyltrimethoxysilane
2.0 parts diisobutylamine

0.06 part formic acid

0.03 part This mixture was heated to 110° C. for 3.0 hours under a nitrogen atmosphere. At this point, the silicone polymer was found to be end-substituted with CH3(CH3O)2Si- groups by Si FTNMR analysis. The polymer had a viscosity of 130,000 centipoise at 25°C after this terminal substitution. Example 2 A dimethylmethoxy-terminated dimethylsilicone low modulus additive is first reacted with a mixture of 100 parts dimethyldichlorosilane, 26 parts acetone and 10 parts water in a glass-lined reaction kettle equipped with a stirrer and an outlet for HCl release. It was manufactured using the method of

That is, while stirring dimethyldichlorosilane vigorously, the acetone/water mixture was slowly added. The reaction temperature decreased during this addition, but was adjusted so as not to drop below 5°C. HCl was continuously vented. After the addition of the acetone/water mixture is complete, the reaction mixture is
Stirred for 30 minutes at a temperature of 0-50°C. The reaction mixture was then vacuum stripped to 125°C at a pressure of 20-30 mmHg to obtain a low molecular weight dimethylchlorodimethylsilicone oil.

47 parts of methanol were slowly added to 100 parts of this dimethylchloro-terminated dimethylsilicone oil while stirring constantly and maintaining the batch temperature below 40°C. After stirring for 1 hour at or below 40°C, the liquid phase was separated. The lower phase was silicone oil. The batch was then vacuum stripped to 80° C. at 30-40 mm Hg and 1 part Na HCO and Norite FQA were added to the batch to neutralize and decolorize the batch. The batch was then cooled to below 50 DEG C. and filtered to obtain a low molecular weight dimethylmethoxy terminated dimethylsilicone oil having the following properties:

Nature Quality Transparency
Transparent, colorless Gardner hue
Maximum 1 Silanol content Maximum 0
．． 4% Chlorine%
Max 0.008% Methoxy content 5.5
-8.0% viscosity
5-11 centistokes
Refractive index, 20℃
1.3990-1.4020 Example 3 Example 3 is a 30mm Werner Preiderer
ner Pfleiderer) illustrates a method for continuously manufacturing the compositions of the present invention using a twin screw extruder.

Sixteen parts of fumed silica treated with octamethylcyclotetrasiloxane (ie, D4) was continuously added to barrel 1 of the extruder. Similarly, 100 parts of the methyldimethoxy-terminated polymer prepared in Example 1 and 1.50 parts of cyanoethyltrimethoxysilane were added to barrel 1.
parts were added continuously. Example 2 for barrel 8 of the extruder
30 parts of dimethyl methoxy-terminated dimethyl silicone oil prepared in Example 1 was added continuously as a low modulus additive. Barrel 12 contained 1.1 parts of 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate, 0.45 parts of dibutyltin-bis-acetylacetonate curing catalyst,
0.45 parts of a 2,4-pentanedione chelate ligand and 1.50 parts of methyltrimethoxysilane were added. This Werner Preiderer twin screw extruder
A temperature of 5°C was maintained. Extruder barrel 1 for degassing
Vacuum was applied to 1. The RTV sealant composition was manufactured at a rate of 30 pounds/hour.

The composition prepared in Example 3 was tested for physical properties according to ASTM, both cured and uncured, accelerated storage stability (uncured sealant stored at 100° C. for 24 hours) and low modulus (ISO 8339- 1984E and 8
340-1984E). AST
M physical properties were measured after 7 days of curing at 72° C. and 50% relative temperature (standard curing conditions). Accelerated storage aging AS
TM physical properties were measured after heating the uncured sealant at 100° C. for 24 hours and then curing for 7 days at standard cure conditions. ISO low modulus was measured after 28 days of curing under standard curing conditions, followed by 4 days of water soaking under standard conditions and drying for 24 hours.

The test results are shown in Tables 1 and 2. Example 4 The method of Example 3 was repeated, only without the dimethylmethoxy terminated silicone oil. In Example 4, 2
30 parts of trimethyl terminated dimethyl silicone oil having a viscosity of 100 centipoise at 5° C. was added continuously to barrel 8 of the extruder. The test results are shown in Tables 1 and 2. Example 5 The method of Example 3 was applied to barrel 8 of an extruder at 25°C.
was repeated by continuously adding a silicone plasticizer formulation consisting of 20 parts of trimethyl terminated dimethyl silicone oil having a viscosity of 100 centipoise and 10 parts of monomethoxy terminated silicone oil prepared in Example 2. The test results are shown in Tables 1 and 2. Example 6 The method of Example 3 was repeated using a trimethyl terminated dimethyl silicone oil 15 having a viscosity of 100 centipoise at 25°C.
by continuously adding a silicone plasticizer formulation consisting of 1.5 parts and 15 parts of monomethoxy-terminated silicone oil prepared in Example 2 to barrel 8 of the extruder. The test results are shown in Tables 1 and 2. Example 7 The method of Example 3 was repeated using a trimethyl terminated dimethyl silicone oil 10 having a viscosity of 100 centipoise at 25°C.
Example 2 was repeated by continuously adding a silicone plasticizer formulation consisting of 20 parts of monomethoxy-terminated silicone oil prepared in Example 2 to barrel 8 of the extruder. The test results are shown in Tables 1 and 2. Example 8 Example 8 shows that the monomethoxy-terminated, low modulus silicone additive prepared in Example 2 converts hexamethyldisilazane into a polyalkoxy-terminated polydiorganosiloxane (A).
It is illustrated that alkoxy curable one-part RTV compositions containing 2 parts per 100 parts do not work, giving RTV compositions with poor storage stability.

16 parts of D4-treated fumed silica, 100 parts of the methyldimethoxy-terminated polymer prepared in Example 1, and 1.50 parts of cyanoethyltrimethoxysilane were added sequentially to barrel 1 of the extruder. Extruder barrel 8 contains 10 parts trimethyl terminated dimethyl silicone oil having a viscosity of 100 centipoise at 25°C and Example 2
A silicone plasticizer formulation consisting of 20 parts of monomethoxy-terminated silicone oil prepared in Example 1 was added continuously. Barrel 12 contains 1.0 parts of 1,3,5-tris(3-trimethoxysilylpropyl)-isocyanurate, 1.5 parts of methyltrimethoxysilane, 2.0 parts of hexamethyldisilazane stabilizing scavenger, and dibutyltin. 0.20 part of diacetate condensation curing catalyst was added. The Werner Preiderer twin screw extruder was maintained at a temperature of 75°C. A degassing vacuum was applied to barrel 11 of the extruder. RTV
The sealant was produced at a rate of 30 pounds/hour.

The storage stability of the composition prepared in Example 8 was tested by storing the uncured composition at 100° C. for 24 hours. During this storage period, the composition underwent significant polymer degradation and therefore did not undergo subsequent curing. Example 9 The process of Example 8 was repeated only without using the monomethoxy terminated, low modulus silicone oil prepared in Example 2. The composition prepared in Example 9 was 24 at 100°C.
It showed no signs of disintegration after time accelerated shelf life testing.

Examples 10 and 11 below illustrate that low modulus properties are only imparted when using low molecular weight monoalkoxy-terminated polydiorganosiloxane oils in comparison with high molecular weight monoalkoxy-terminated polydiorganosiloxane oils. It is something to do. Example 10 Dimethylmonomethoxy-terminated polydimethylsiloxane as prepared in Example 1, with n = 350, was mixed with 100 parts by weight of silanol-terminated polydimethylsiloxane polymer, 2 parts by weight of dimethyldimethoxysilane, and 0.5 parts by weight of diisobutylamine. It was produced by mixing 1 part by weight and 0.05 part by weight of formic acid at 110°C for 3 hours. The reaction mixture was kept strictly dry with a constant N2 purge. At this point a vacuum of 60 mm Hg was applied to strip excess volatiles. The final product was tested by FTNMR analysis and confirmed to be a dimethylmonomethoxy terminated polydimethylsiloxane polymer (n=350). Example 11 The method of Example 3 was simply used there. It was repeated using the high molecular weight monomethoxy terminated polydimethylsiloxane oil prepared in Example 10 in place of the low molecular weight monomethoxy terminated polydimethylsiloxane oil prepared in Example 2. The test results are shown in Tables 1 and 2.

[0081]

[Table 1]

[0082]

[Table 2]

Claims (12)

[Claims] Claim 1: The following components: (A) have a viscosity of about 100 to about 1,000,000 centipoise at 25°C, each polymer chain-terminated silicon atom having at least two alkoxy groups as terminal substituents; (B) having only one alkoxy group on each terminal silicon atom in the polymer chain; , about 1 to about 40 parts of a monoalkoxy-terminated polydiorganosiloxane polymer having a viscosity in the range of about 5 to about 95 centipoise at 25°C and in which the organo groups are C1-15 monovalent hydrocarbon groups; (C) about 0 to about 40 parts of reinforcing filler; (D) general formula: [Image Omitted] (wherein R5 is a group selected from C1-18 monovalent hydrocarbon groups and substituted hydrocarbon groups; and R6, R7
and R8 is hydrogen, R5, OR5, -Si(R5
)3, -OSi(R5)3, which is a monovalent group which may be the same or different selected from the group consisting of aryl, acyl and nitrile groups); E) about 0 to about 5 parts of a β-diketone having the general formula: (wherein R6, R7 and R8 are as defined above);
F) Formula: (wherein R3 and R4 are C1-8 monovalent hydrocarbon groups, t is 0 to 3, and Z is further ether, epoxy, isocyanato, cyano, isocyanurate, acryloxy and acyloxy groups; (G) general formula: 2] (wherein each R3 and R4 is independently 1 to about 18
R5 is a C2-12 divalent hydrocarbon group, and t is a number ranging from about 0 to about 3). Auxiliary adhesion promoter cyanofunctional polyalkoxysilane with 0
0 to 2 parts; and (H) crosslinking agent polyalkoxysilane
1. A scavenger-free, storage-stable, one-part, room-temperature-curing silicone composition with improved low modulus properties comprising from about 10 parts to about 10 parts. 2. The polyalkoxy-terminated polydiorganosiloxane (A) has the general formula: [Formula 3] (wherein each R, R1 and R2 are independently an unsubstituted or substituted C1-15 monovalent hydrocarbon group, and n is about 5
2,500 and a is an integer of 0 or 1). 3. The composition of claim 1, wherein the monoalkoxy-terminated polymer (B) has the formula: ##STR4## where m ranges from about 1 to about 40. 4. The composition according to claim 1, wherein the condensation catalyst (D) is di(n-butyl)tin bis(acetylacetonate). [Claim 5] Adhesion promoter polyalkoxysilane (F
) has the general formula: [Formula 5] (wherein, G is a group selected from R11, a group of the formula:, a styryl group, a vinyl group, an allyl group, a chlorallyl group, and a cyclohexenyl group, and R13
is a C1-8 monovalent hydrocarbon group or a cyanoalkyl group, R14 is a C1-8 monovalent hydrocarbon group or a cyanoalkyl group, and R15 is an alkylenearylene group, an alkylene group, a cycloalkylene group, and Claim 1 is an isocyanato-functionalized polyalkoxysilane having a C2-12 divalent hydrocarbon group selected from halogenated alkylenearylene groups, alkylene groups and cycloalkylene groups, and b is from 0 to 3. Compositions as described. 6. The composition of claim 5, wherein the isocyanato-functionalized polyalkoxysilane is 1,3,5-tristrimethoxysilylpropylisocyanate. 7. The auxiliary adhesion promoter cyano-functional polyalkoxysilane (G) is γ-cyanopropyltrimethoxysilane, 3-(cyanoethoxy)-3-methylbutenyltrimethoxysilane, β-cyanoethylmethyldimethoxysilane, β-cyanoethyltriethoxysilane, β-
7. The compound according to claim 6, which is selected from the group consisting of cyanoethyltrimethoxysilane, 2-cyanoethylmethyldiethoxysilane, 3-cyanopropyltriethoxysilane, cyanopropylmethyldimethoxysilane and 1-cyanoethyltris(methoxyethoxy)silane. Composition. 8. The composition of claim 1, wherein the β-diketone (E) is present in an amount ranging from about 0.2 to about 0.8 parts. 9. The composition of claim 1, wherein the crosslinker polyalkoxysilane (H) is present in an amount ranging from about 0.1 to about 2.0 parts. 10. The composition of claim 1, wherein the reinforcing filler (C) is present in an amount ranging from about 5 to about 40 parts. Claim 11: Furthermore, 10 to 5,000 at 25°C.
A claim comprising from about 1 to about 50 parts by weight of a triorganosilyl-terminated diorganopolysiloxane having a viscosity of 0 centipoise and wherein the organo groups are monovalent hydrocarbon groups preferably having from 1 to 8 carbon atoms. Item 1. The composition according to item 1. 12. By weight, the following components: (A) General formula: [Image Omitted] (wherein each R, R1 and R2 are a methyl group, and n
is an integer in the range of about 50 to about 2,500, and a is an integer of 0 or 1), and at 25°C
Polyalkoxy terminated polydiorganosiloxane 100 having a viscosity of 0 to about 1,000,000 centipoise
(B) has the formula: [Image Omitted] (wherein R, R1 and R2 are each a methyl group, and m ranges from about 10 to about 20) at 25°C. from about 15 to about 25 parts of a monoalkoxy-terminated polydiorganosiloxane having a viscosity in the range of 60 centipoise; (C) from about 5 to about 40 parts of fumed silica filler;
D) Di(n-butyl)tin bis(acetylacetonate)
about 0.2 to about 0.4 parts; (E) about 0.3 to about 0.5 2,4-hexanedione
(F) about 0.3 to about 0.7 parts of 1,3,5-tristrimethoxysilylpropylisocyanate; (G) β-
Cyanoethyltrimethoxysilane from about 0.3 to about 0.
7 parts; (H) Methyltrimethoxysilane from about 0.5 to about 1.
0 parts; and (I) having a viscosity of 10 to 5000 centipoise at 25°C, preferably containing 1 to 8 organo groups;
from about 1 to about 5 triorganosilyl-terminated diorganopolysiloxanes, which are monovalent hydrocarbon radicals having from about 1 to about 5 carbon atoms.
1. A scavenger-free, storage-stable, one-component, room-temperature-curing silicone composition with improved adhesion without the use of a primer, comprising: 0 parts;