JP2003516458A - Room temperature curable silicone sealant - Google Patents

Abstract

  (57) [Summary] One-part room temperature vulcanizable silicone sealant compositions containing moisture-curable polyorganosiloxane polymers have a 50% elongation at cure of about 30 to about 100 pounds per square inch of tensile modulus at 50% elongation. Low tendency to stain the substrate upon contact with

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a one-part room temperature vulcanizable (curable) (“RTV”) silicone sealant, and more particularly to a one-part RTV silicone sealant that has a low tendency to stain porous substrates.

[0002]

[Prior art]

Silicone compositions that cure to elastomers are widely used as sealants and caulks in construction and construction. Known silicone sealant compositions are based on substrates using them, in particular marble, concrete, granite,
It can soil porous substrates such as sandstone and limestone. Also, the exposed surface of the cured sealant tends to attract dust (dirt, dust), dirt and other forms of contaminants.

Many attempts have been made to reduce the problem of attracting pollution and dirt. For example, Mikami et al., US Pat. No. 5,432,218, discloses a room temperature curable polysiloxane having improved stain resistance and paintability with components containing unsaturated fatty acids such as soybean oil fatty acid, linseed oil fatty acid and tung oil fatty acid. It is disclosed. Similarly, a combination of a drying oil and zinc oxide that extends the useful life of the drying oil is disclosed as a component that extends the dirt- and dust-free action of the two-part silicone polymer sealant (US Pat. No. 5,733,960). issue). Kinami et al. US Patent No. 5
No. 326816 discloses organopolysilethylene siloxane sealants.

[0004]

[Outline of the Invention]

The present invention, in its first embodiment, relates to a one-part room temperature vulcanizable silicone sealant composition comprising a moisture-curable polyorganosiloxane polymer and a filler, wherein the sealant composition has an elongation of 50% when cured. The% tensile modulus is from about 30 to about 100 pounds per square inch and has a low tendency to stain the substrate when contacted with the cured sealant.

In a second embodiment, the present invention relates to a silicone sealant comprising: (a) (i) an organopolysiloxane polymer containing an average of greater than 1 and less than 2 reactive sites per molecule, provided that Greater than about 90 parts by weight per 100 parts by weight of the organopolysiloxane polymer has one or more reactive sites per molecule), and (ii) one or more hydrolyzable groups per molecule, and the organopolysiloxane A moisture-curable organopolysiloxane component comprising a mixture with a polyfunctional organosilicon compound containing one or more functional groups capable of reacting with the reactive sites of a siloxane polymer, or a reaction product thereof, and (b) condensation curing It comprises a catalyst and (c) a filler.

In a third embodiment, the present invention relates to a silicone sealant comprising a moisture curable organopolysiloxane component, the silicone sealant comprising (i) one hydrolyzable silyl end group per molecule. At least one linear organopolysiloxane polymer having one non-hydrolyzable silyl end group;
A mixture with a linear organopolysiloxane polymer having two hydrolyzable silyl end groups per molecule, said mixture comprising an average of more than 1 and less than 2 hydrolyzable silyl end groups per molecule. (Ii) It contains a mixture with a polyfunctional organosilicon compound containing two or more hydrolyzable groups per molecule, or a reaction product thereof.

The compositions of the present invention have a low tendency to stain or soak into the substrate upon curing and a low tendency to attract stains onto the surface of the sealant.

[0008]

DETAILED DESCRIPTION OF THE INVENTION

In a preferred embodiment, the composition of the invention comprises 100 parts by weight of the composition ("p
bw ") on the basis of 10 pbw or less, more preferably 5 pbw or less, even more preferably 2 pbw or less non-curable plasticizer. The most preferred compositions of this invention contain no or substantially no conventional non-hardening plasticizers.
Non-curable plasticizers are useful in lowering the tensile modulus of the cured sealant composition and are a substantially chemically inert component of the sealant composition, i.e., moisture-curing conditions. It is a compound having no functional group capable of reacting with the curable organopolysiloxane polymer. Suitable non-curable plasticizers include, for example, polyorganosiloxane plasticizers such as trimethylsilyl-terminated polydimethylsiloxane polymers, and organic plasticizer compounds such as dioctyl phthalate.

In a preferred embodiment, the sealant of the present invention, upon curing, has an ASTM D
412 has a tensile modulus at 50% elongation of about 30 to about 100 pounds per square inch ("psi"), more preferably about 45 to about 65 psi, and even more preferably about 45 to about 55 psi.

In a preferred embodiment, the silicone sealant of the present invention is 20-90 pbw, more preferably 30-7, based on 100 parts by weight of the sealant composition.
5 pbw, more preferably 40-60 pbw moisture curable organopolysiloxane polymer, 0.1-10 pbw, more preferably 1-7 pbw, even more preferably 3-5 pbw catalyst, 1-80 pbw, more preferably 2 78 pb
w, and more preferably 3 to 65 pbw filler.

The organopolysiloxane polymer is any organopolysiloxane having an average of greater than 1 and less than 2 per molecule, preferably 1.1 to 1.9, more preferably 1.3 to 1.7 reactive sites. It may be a siloxane polymer. In a preferred embodiment, based on 100 pbw of the organopolysiloxane polymer, about 95 pbw or more, more preferably about 98 pbw or more, even more preferably about 9 pbw or more.
9 pbw or more, and most preferably substantially all organopolysiloxane polymers have 1 or more reactive sites per molecule. Suitable reactive sites are silicon-bonded substituents, for example, under selected reaction conditions, as described in detail below, or under the processing conditions expected during compounding of the compositions of the present invention. Or a hydrogen atom, an alkenyl group and a hydrolyzable group which react with the primary functional group of the polyfunctional organosilicon compound of the present invention under moisture curing conditions. Suitable hydrolyzable groups include, for example, hydroxy groups, alkoxy groups, oximo groups, amino groups, aminooxy groups, and acyloxy groups.

In a first preferred embodiment, the organopolysiloxane polymer comprises a mixture of an organopolysiloxane polymer having two reactive sites per molecule and an organopolysiloxane polymer having one reactive site per molecule. Including.
In a second preferred embodiment, the organopolysiloxane consists essentially of a mixture of an organopolysiloxane polymer having two reactive sites per molecule and an organopolysiloxane polymer having one reactive site per molecule. Become. In a third preferred embodiment, the organopolysiloxane polymer consists only of a mixture of an organopolysiloxane polymer having two reactive sites per molecule and an organopolysiloxane polymer having one reactive site per molecule.

In a first preferred embodiment, the organopolysiloxane mixture comprises one or more linear organopolysiloxane polymers having two reactive sites per molecule,
Linear organopolysiloxane polymer having one reactive site per molecule 1
Including species and more. In a second preferred embodiment, the organopolysiloxane mixture comprises substantially one or more linear organopolysiloxane polymers having two reactive sites per molecule and a linear organopolysiloxane polymer having one reactive site per molecule. One or more organopolysiloxane polymers. In a third preferred embodiment, the organopolysiloxane mixture comprises one or more linear organopolysiloxane polymers having two reactive sites per molecule and a linear organopolysiloxane having one reactive site per molecule. It is composed of one or more polymers.

In the case of a mixture of a linear organopolysiloxane polymer having two reactive sites per molecule and one or more linear organopolysiloxane polymers having one reactive site per molecule, Relative quantities can be expressed in different ways. That is, 5 of the terminal silicon atoms of the linear organopolysiloxane polymer
0-99%, more preferably 60-95%, even more preferably 70-90% are substituted with reactive substituents such as hydrolyzable groups, and 1-50% of the linear organopolysiloxane polymer. , More preferably 20-40%, and even more preferably 10-30% are substituted with non-reactive substituents such as alkyl groups.

Suitable organopolysiloxane polymers are prepared by conventional polymerization techniques. However, the relative amounts of the reactants are adjusted to obtain an organopolysiloxane polymer having a predetermined amount of reactive sites per molecule.

In a preferred embodiment, the functional organopolysiloxane polymer having silicon-bonded hydroxy, ie silanol, is a cyclic polysiloxane such as octamethylcyclotetrasiloxane and a trialkyl terminated polydimethylsiloxane such as trimethyl terminated polydimethylsiloxane. It is made by a base-catalyzed equilibration / chain extension polymerization reaction of a dialkylsiloxane polymer. Here, a stoichiometric amount of water is added to the reaction mixture to the selected average silanol content. Next, the product of this polymerization reaction is neutralized with phosphoric acid.

In a preferred embodiment, the organopolysiloxane polymer is 50 at 25 ° C.
00-500000 centipoise ("cp"), preferably 20000-150
It has a viscosity of 000 cp, more preferably 40,000 to 80,000 cp.

In a preferred embodiment, the organopolysiloxane polymer comprises a mixture of two or more silicone polymers or copolymers having structural units according to the structural formula (I) below. R _a SiO _{4-a / 2} where each R is independently H, hydroxy or a monovalent hydrocarbon group,
≦ a ≦ 4. However, 1 or more R per molecule of the organopolysiloxane polymer is H, hydroxy or alkenyl, and on average, more than 1 and less than 2 R groups per molecule of the organopolysiloxane polymer are H, hydroxy or alkenyl, respectively. Is.

Suitable monovalent hydrocarbon groups include monovalent acyclic hydrocarbon groups, monovalent alicyclic hydrocarbon groups and monovalent aromatic hydrocarbon groups.

As used herein, the term “monovalent acyclic hydrocarbon group” means a monovalent straight or branched chain hydrocarbon group, preferably 1-20 per group. Carbon atoms, which may be saturated or unsaturated, and optionally substituted, eg by one or more halogen atoms. Suitable monovalent acyclic hydrocarbon groups include, for example, alkyl groups such as methyl, ethyl, sec-butyl, tert-butyl, octyl, dodecyl, stearyl and eicosyl, haloalkyls such as trifluoropropyl, eg There are alkenyl groups such as ethenyl and propenyl, as well as alkynyl groups such as propynyl and butynyl.

The term “alicyclic hydrocarbon group”, as used herein, means a group containing one or more saturated hydrocarbon rings, preferably 6 per ring per group. Containing 10 to 10 carbon atoms and optionally replacing one or more rings with one or more alkyl groups, each preferably containing 2 to 6 carbon atoms per group And may be a condensed ring in the case of two or more rings. Suitable monovalent alicyclic hydrocarbon groups include, for example, cyclohexyl and cyclooctyl.

As used herein, the term “monovalent aromatic hydrocarbon group” means a hydrocarbon group containing one aromatic ring per group, and in some cases, one or more aromatic rings. Alkyl groups, each of which preferably contains from 2 to 6 carbon atoms per group. Suitable monovalent aromatic hydrocarbon radicals include, for example, phenyl, tolyl, xylyl, 2,4,6-trimethylphenyl and naphthyl.

In a highly preferred embodiment, the organopolysiloxane polymer consists of a mixture of two or more linear polymers or copolymers of the structural formula (II):

[0024]

[Chemical 2]

[0025] Where R¹, R², R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹And R^TenEach independently
And H, hydroxy or a monovalent hydrocarbon group. However, 1 or more R per molecule ¹ , R², R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹Or R^TenIs H, hydroxy or a
Lucenyl, an average of more than 1 and no more than 2 molecules per molecule for all molecules in this mixture.
Man R¹, R², R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹Or R^TenAre H and hydro respectively
It is xy or alkenyl. Further, m is 5000 to 500,000 cp at 25 ° C.
It is selected to give a polymer that exhibits a viscosity.

In a preferred embodiment, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl. And R ² and R ¹⁰ are each hydroxy, (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl.

Also, in a preferred embodiment, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently (C ₁ -C ₈ ) alkyl, fluoroalkyl or Phenyl and R ² and R ¹⁰ are each H, alkenyl, (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl.

Suitable polyfunctional organosilicon compounds are suitable under the processing conditions expected under the selected reaction conditions, such as H, alkoxy or alkenyl groups, or during the compounding of the compositions of the invention. Containing a primary functional group capable of reacting with a reactive site of the organopolysiloxane polymer under or under moisture curing conditions,
And a secondary functional group that is reactive under room temperature vulcanization conditions and thus allows curing of the sealant composition by moisture, preferably an alkoxy group, for example.
It contains one or more hydrolyzable groups such as oximo group, amino group, aminooxy group or acyloxy group per molecule. The polyfunctional organosilicon compound can be a silane or a partial hydrolysis product of a silane.

Suitable polyfunctional organosilicon compounds are, for example, vinyltrimethoxysilane, tetramethoxysilane, methyltriethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methylphenyldiethoxysilane, 3,3,3. −
Trifluoropropyltrimethoxysilane, methyl (tri (methylethylketoximo) silane, ethyl (tri (N, N-diethylamino) silane, methyltri (
N-methylacetamide) silane, n-propyl orthosilicate and ethyl polysilicate.

In a preferred embodiment, the polyfunctional organosilicon compound has the following structural formula (III)
Is to have. R ¹¹ ₄ Si (III) wherein each R ¹¹ is independently H, alkoxy, alkenyl, oximo, amino, aminoxy, acyloxy or a monovalent hydrocarbon group. However, 1 or more of R ¹¹ is H
, Alkoxy or alkenyl, and one or more of the other R ¹¹ is alkoxy, oximo, amino, aminoxy or acyloxy.

In a first preferred embodiment, at least three R ¹¹ substituents are each alkoxy, more preferably (C ₁ -C ₈ ) alkoxy, even more preferably methoxy or ethoxy and the remaining R ¹¹ substituents are In some cases, (C ₁ -C ₈ ) alkyl, (C ₂ —
C ₈₎ alkenyl, aryl, or fluoroalkyl. Preferred polyfunctional organosilicon compounds include, for example, vinyltrimethoxysilane, tetramethoxysilane, methyltriethoxysilane, tetraethoxysilane and methyltrimethoxysilane. The most preferred polyfunctional organosilicon compound comprises methyltrimethoxysilane.

In a second preferred embodiment, one R ¹¹ is H or alkenyl and at least two R ¹¹ substituents are each alkoxy, more preferably (C ₁ -C ₈ ) alkoxy, even more preferably methoxy or Ethoxy, and (C ₁ -C ₈ ) alkyl, aryl or fluoroalkyl when the remaining R ¹¹ substituents are present. Preferred polyfunctional organosilicon compounds include, for example, vinyltrimethoxysilane and vinyltriethoxysilane.

In a preferred embodiment, the moisture curable organopolysiloxane polymer is from about 1.0 to about 30 with 100 pbw of the functional organopolysiloxane polymer.
pbw, more preferably about 2.0 to about 15 pbw, most preferably about 3.0 to about 10 pbw by reaction with a polyfunctional organosilicon compound.

In a preferred embodiment, suitable moisture curable organopolysiloxane polymers have silanols, organopolysiloxane polymers having silicon-bonded hydroxy and alkoxy primary functional groups during compounding of the compositions of the present invention. It is formed by a condensation reaction in situ with a polyfunctional organosilicon compound.

Suitable moisture curable organopolysiloxane polymers are also formed by reacting the organopolysiloxane polymer with a polyfunctional organosilicon compound prior to addition to the composition of the present invention. In a first embodiment, a moisture curable organopolysiloxane polymer comprises a hydroxy-functional organopolysiloxane polymer and an alkoxy primary functional group in the presence of a condensation cure catalyst, such as a condensation cure catalyst described in more detail below. It is formed by a condensation reaction with a polyfunctional organosilicon compound having. In a second embodiment, the moisture curable organopolysiloxane polymer has a (i) alkenyl functionality under hydrosilylation conditions in the presence of a suitable hydrosilylation catalyst, such as a platinum or rhodium containing hydrosilylation catalyst. Addition reaction of an organopolysiloxane polymer with a polyfunctional organosilicon compound having a hydride primary functional group, or (ii) addition reaction of a hydrido functional organopolysiloxane polymer with a polyfunctional organosilicon compound having an alkenyl primary functional group Formed by.

The condensation cure catalyst of the composition of the present invention catalyzes the room temperature crosslinking of the crosslinkable organopolysiloxane polymer in the presence of moisture. Suitable condensation cure catalysts include, for example, dibutyltin dilaurate, dibutyltin diacetate, and dialkyltin carboxylates such as tin-2-ethylhexanoate,
For example, alkyl titanates such as tetrabutyltin titanate, tetra-n-propyl titanate and the like, as well as organosiloxy titanium compounds. Various other condensation catalysts are known in the art.

[0037]   In a preferred embodiment, the condensation cure catalyst comprises a compound of structural formula (IV):

[0038]

[Chemical 3]

Here, X is titanium, lead, tin, zirconium, antimony, iron, cadmium,
Barium, manganese, zinc, chromium, cobalt, nickel, aluminum, gallium or germanium, R ¹³ is a divalent, optionally substituted hydrocarbon group, and R ¹⁴ , R ¹⁶ and R ¹⁹ are Each is independently a monovalent hydrocarbon group, R ¹⁵ and R ¹⁸ are each independently H or a monovalent hydrocarbon group, and R ¹⁷ is a monovalent hydrocarbon group, amino, ether, or a formula ( C _q H _2q O) _v R ²⁰ is a polyether group, R ²⁰ is a monovalent hydrocarbon group, q and v are each an integer, and 2 ≦ q ≦ 4, 1 ≦
v ≦ 20, and s and t are numbers 0.7 ≦ s ≦ 1.3 and 0.8 ≦ t ≦ 1.2, respectively. In a preferred embodiment X is titanium. In the preferred embodiment, s and t are each 1.

In a highly preferred embodiment R ¹³ has 2 to 20 carbon atoms per group, more preferably 2 to 10 carbon atoms, optionally halogen, cyano, nitro, carboxy, carboxyester. A group, an acylhalohydrocarbon group or a divalent hydrocarbon group which may be substituted with a hydrocarbon substituent having 8 or less carbon atoms per group.

In a preferred embodiment, X is titanium, R ¹³ is propyl, R ¹⁵ and R ¹⁸ are each H, R ¹⁴ , R ¹⁶ and R ¹⁹ are each methyl, and R ¹⁷ is ethyl. Is.

The preparation of compounds having structural formula (III) is described in US Pat. Nos. 3,689,454 and 3,779,986.

In a preferred embodiment, the composition of the present invention comprises 0.1-10 pbw, preferably 1-7 pbw, most preferably 3-5 pbw of condensation cure catalyst.

The filler component of the composition of the present invention comprises a reinforcing filler, a semi-reinforcing filler, a non-reinforcing filler or a mixture thereof.

In a preferred embodiment, the filler of the present invention comprises a reinforcing filler. Suitable reinforcing fillers include, for example, fumed silica, surface treatments such as hydrophobized fumed silica, carbon black, titanium dioxide, ferric oxide, aluminum oxide, and other metal oxides. It is commercially available from that supplier. In a preferred embodiment, the reinforcing filler comprises fumed silica.

In a preferred embodiment, the silicone sealant of the present invention is 1-10 pbw, more preferably 2-8 pb, based on 100 parts by weight of the sealant composition.
w, more preferably 3 to 5 pbw of reinforcing filler.

The filler may optionally include semi-reinforcing or non-reinforcing fillers. Suitable semi-reinforcing or non-reinforcing fillers include, for example, quartz, precipitated silica, hydrophobized precipitated silica, calcium carbonate, which are commercially available from several sources. In a preferred embodiment, the semi-reinforcing or non-reinforcing filler comprises calcium carbonate.

In a preferred embodiment, the silicone sealant of the present invention is 0-70 pbw, more preferably 30-60, based on 100 parts by weight of the sealant composition.
It contains pbw, more preferably 40-60 pbw of semi-reinforcing or non-reinforcing filler.

Optionally, the composition of the present invention further comprises a hydrocarbon fluid to control the viscosity of the composition. Hydrocarbon fluid, for example heptane, eicosane, cyclohexane, cyclooctane, aliphatic, such as benzene and toluene, or mixtures of these fluids, including cycloaliphatic and aromatic (C ₅ -C ₂₄₎ hydrocarbon fluids it may be any (C ₅ -C ₂₄₎ hydrocarbon fluid. In a preferred embodiment, the hydrocarbon fluid, one or more linear or branched (C ₅ -C ₂₄₎ alkane, more preferably consists of one or more linear (C ₁₀ -C ₁₈₎ alkane. Suitable hydrocarbon fluids include, for example, heptane, hexane, octane, nonane, decane, undecane, dodecane, heptadecane, octadecane, eicosane. In a preferred embodiment, the composition of the present invention comprises 1 to 40 pbw, more preferably 2 to 20 pbw, and even more preferably 3 to 10 pbw hydrocarbon fluid.

The silicone sealant composition of the present invention may optionally further comprise other known ingredients, as long as it is free of stains, does not attract dirt and does not interfere with other properties of the silicone sealant composition, for example: Dyes, pigments, antioxidants, UV
Stabilizers, adhesion promoters, heat stabilizers, biocides, non-silicone polymers and the like can be used in the composition.

The composition of the present invention is prepared by combining the components of the composition together and mixing. This mixing can be done either as a batch process or as a continuous process, and any convenient mixing device can be used to mix the components, for example a planetary mixer. In a preferred embodiment, the composition of the present invention is prepared by continuously compounding the composition in an extruder, preferably a twin-screw extruder.

To use the composition of the present invention, the composition is exposed to ambient moisture to cure the composition. The composition is preferably packaged in a moisture-tight package until used. In a preferred embodiment, this composition is used to seal the gap between the first substrate and the second substrate. In this case, the second substrate is spaced from the first substrate to form a gap, and an amount of the composition effective to fill the gap is used and the composition is Cure in place to form an elastomeric seal between the substrates.

A first substrate, a second substrate located at a distance from the first substrate, and a first substrate
An assembly comprising a cured silicone sealant composition of the present invention disposed between and bonded to a second substrate and each of these substrates is also part of the present invention, the assembly comprising: Shows improved resistance to attracting dust.

In a preferred embodiment, at least one of the first and second substrates is a porous substrate, for example a marble, concrete, granite, sandstone or limestone substrate.

[0055]

【Example】

Example 1 and Comparative Examples C1-C6 Sealant compositions as a whole at 100 pbw, with the following components as Werner-Pfleidere:
The composition of Example 1 was made by combining in a r twin-screw extruder. (A) 44.4 pbw organopolysiloxane polymer (hydroxy-terminated dimethylsiloxane polymer containing 18.6 wt% trimethylsilyl end groups and 81.4 wt% dimethylsilanol end groups, based on the total weight of the end groups. Silicon. About 1.63 bound hydroxy groups per molecule, viscosity 54000 centipoise), (b) 5.0 pbw reinforcing filler (octamethylcyclotetrasiloxane treated fumed silica), (c) 43.0 pbw non-. Reinforcing filler (calcium carbonate filler treated with stearic acid, Hi-Pflex 100, Specialty Minerals Inc), (d) 5.0 pbw linear aliphatic (C ₁₂ -C ₁₅ ) hydrocarbon mixture (Conosol D -20
0, Conoco), and (e) 2.60 pbw of (i) 57 wt% of polyfunctional silicon compound (methyltrimethoxysilane), (ii) 11 wt% of adhesion promoter (Tris- [3- (tri Methoxysilyl) propyl] isocyanurate), and (iii) 32 wt% of a curing catalyst (1,3-propanedioxytitanium (ethylacetoacetate-acetylacetonate)), a liquid blend (wt% is based on the weight of the entire blend). ).

The organopolysiloxane polymer, fumed silica and calcium carbonate were continuously fed to the barrel 1 of the extruder. Further hydrocarbon fluid and liquid blend were added downstream. The barrel 12 was evacuated. The processing temperature of the extruder was maintained at 75 ° C. in barrel 1 to barrel 11. Barrels 12-14 were cooled so that the RTV sealant exiting the extruder was at 25-35 ° C.

After standing at room temperature for 4 days, the sealant composition of Example 1 was tested for various rheological properties and post-cure physical properties. The ASTM test methods used and the test results are shown in Table I below.

Table I ──────────────────────────────────── Characteristics ASTM Test Method Example 1 ─ ─────────────────────────────────── Specific gravity C97 1.36 Coating speed (g / min) C1183 279 Finger Drying time (hours) C679 6 1/8 inch Curing time (hours) --24 Boeing Flow (inch) D2202 0.10 Properties of sheet cured at room temperature for 7 days Durometer, Shore A C661 24 Tensile strength (psi) ) D412 251 Elongation (%) D412 649 Modulus at 50% elongation (psi) D412 56 14 Peel adhesion after 14 days cure (ppi /% cohesive failure) C794 Concrete 32/50 Polished granite 37/100 Marble 32 / 100 Anodized aluminum 28/100 Glass 29/10 0 Duranar ™ coated aluminum 34/100 Polyacrylate 27/100 Polycarbonate 30/100. ────────────────────────────────────

Contamination Test The compositions of Example 1 and the following Comparative Examples C1 to C6 were subjected to a contamination test according to ASTM C-1248 and a long-term contamination test in which the H specimen was placed outdoors at an angle of 75 ° upward for a long time. It was

[0060] ────────────────────────────────────                                                     At 50% elongation   Comparative example Sealant Approximate modulus (psi) ────────────────────────────────────   C1 polyorganosiloxane plasticizer (trimethyl 56           Silyl-terminated polydimethylsiloxane)           Silicone sealant   C2 polyorganosiloxane plasticizer (trimethyl 50           Silyl-terminated polydimethylsiloxane)           Silicone sealant   C3 Silicone Sealant (Dow Corning 790) 25   C4 Silicone Sealant (Dow Corning 795) 65   Contains C5 organic plasticizer (dioctyl phthalate) 35           Silicone treated polyether sealant   Contains C6 organic plasticizer (dioctyl phthalate) 25           Silicone treated polyether sealant. ────────────────────────────────────

Table II below shows the stain characteristics and dust attraction properties of the composition of Example 1 and the compositions of Comparative Examples C1-C6. The meanings of the symbols used in Table II are as follows. No contamination detected (+++), slight contamination detected (++), very little contamination (+), contamination observed (−), obvious contamination (−−), unacceptable contamination (−−−−) ).

Table II ──────────────────────────────────── ASTM C-1248 Results Long Term Contamination Test Results ──────────────────────────────────── Example 1st month 1st month 2nd month 4th month ─ ──────────────────────────────────── 1 No pollution ++＋＋＋＋＋＋＋＋＋＋ C1 Significant pollution ＋＋ －－－ −− C2 Significant pollution ++++ − − −−− C3 Significant pollution ++++++++ C4 Significant pollution ++++++++ C5 Significant pollution ++++ −−−− C6 Significant pollution +++++++++ . ────────────────────────────────────

The composition of the present invention has a low tendency to stain or soak into the substrate and a low tendency to attract dirt and dust to the surface of the sealant. Tensile elastic modulus is 100p
Sealant compositions up to si generally include a non-curable plasticizer to control the tensile modulus of such compositions. However, this non-hardening plasticizer becomes dirty,
It tends to exude and attract dust. The sealant composition of the present invention exhibits a tensile modulus of 100 psi or less and is less prone to soiling or seeping into the substrate as compared to conventional compositions containing uncurable plasticizers, and Low tendency to attract dirt and dust to the surface of the sealant.

Since the compositions of the present invention contain small to negligible amounts of organopolysiloxane polymer having no reactive sites, the cured sealant composition contains small amounts of free organopolysiloxane polymer. It is contained only in a negligible amount. That is, substantially all of the organopolysiloxane polymer is chemically bonded into the crosslinked organopolysiloxane network of the cured sealant composition. Use of organopolysiloxane polymers having one reactive site per molecule in selected amounts to control the crosslink density and tensile modulus of the cured sealant network without the use of non-curable plasticizers. You can The cured sealant composition is substantially free of non-curable plasticizers and organopolysiloxane polymer species that can seep into the substrate from the sealant and contaminate the substrate.
The substantial absence of non-curable plasticizers and free organopolysiloxane polymer species increases the surface tension of the exposed surface of the cured sealant composition, thus deteriorating dust,
It is believed that the affinity for dirt, carbon and other pollutants is reduced.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) C08K 3/26 C08K 3/26 3/36 3/36 5/01 5/01 C08L 83/04 C08L 83 / 04 (72) Inventor Lin, Chiu-Shin United States, 12309, New York, Schenectady, Foxhill Drive, No. 2187 (72) Inventor Lucas, Gary Morgan United States, 12302, New York, Glenville, Street Anthony・ Lane, 21st F term (reference) 4H017 AA03 AA24 AA25 AA27 AA29 AA31 AA39 AB15 AC01 AC05 AC16 AD05 AE03 4J002 CP031 CP051 DE237 DJ016 EA018 EX039 EX079 FB096 FB237 FD016 GJ02

Claims (25)

[Claims] 1. A moisture-curable polyorganosiloxane polymer and a filler, having a tensile modulus at cure of 50% when cured of from about 30 to about 100 pounds per square inch, when contacted with a cured body. A one-pack type room temperature vulcanizable silicone sealant composition having a low tendency to stain a substrate. 2. A composition according to claim 1, comprising 10 parts by weight or less of a non-curable plasticizer, based on 100 parts by weight of the composition. 3. An organopolysiloxane polymer comprising (a) (i) an average of more than 1 and less than 2 reactive sites per molecule, provided that more than about 90 parts by weight per 100 parts by weight of said organopolysiloxane polymer. And (ii) one or more hydrolyzable groups per molecule, and one or more functional groups capable of reacting with the reactive sites of the organopolysiloxane polymer. A silicone sealant comprising a moisture-curable organopolysiloxane component containing a mixture with a polyfunctional organosilicon compound containing ## STR1 ## or a reaction product thereof, (b) a condensation curing catalyst, and (c) a filler. 4. 20 to 90, based on 100 parts by weight of the sealant composition.
The sealant composition of claim 3, comprising parts by weight of moisture curable polyorganosiloxane polymer, 0.1 to 10 parts by weight of catalyst, and 1 to 80 parts by weight of filler. 5. The composition of claim 3 wherein the reactive sites of the organopolysiloxane polymer are silicon-bonded hydrogen, hydroxy or alkenyl substituents. 6. The organopolysiloxane polymer has a viscosity of 5000-500.
The composition of claim 3 which is 000 centipoise. 7. The organopolysiloxane polymer has the structural formula [Chemical 1] [In the formula, R¹, R², R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹And R^TenEach independently
H, hydroxy or monovalent hydrocarbon group, but more than 1 R per molecule¹, R² , R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹Or R^TenIs H, hydroxy or alkeni
And an average R greater than 1 and less than 2 per molecule for all molecules of the mixture. ¹ , R², R³, R^Four, R^Five, R⁶, R⁷, R⁸, R⁹Or R^TenIs H, hydroxy or
Is alkenyl and m has a viscosity of 5000-500000 cp at 25 ° C.
Selected so that the polymer is obtained]]
The composition according to claim 3, which comprises a mixture of two or more of 8. R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl; The composition according to claim 7, wherein ² and R ¹⁰ are each hydroxy, (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl. 9. R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl; The composition of claim 7 wherein ² and R ¹⁰ are each H, alkenyl, (C ₁ -C ₈ ) alkyl, fluoroalkyl or phenyl. 10. The organopolysiloxane polymer has an average of 1.
The composition of claim 3 comprising 1 to 1.9 reactive sites. 11. The organopolysiloxane polymer has an average of 1.
The composition of claim 3 comprising 3 to 1.7 reactive sites. 12. The polyfunctional organosilicon compound has the structural formula R ¹¹ ₄ Si [wherein each R ¹¹ is independently H, alkoxy, alkenyl, oximo, amino, aminoxy, acyloxy or a monovalent hydrocarbon group. Is one or more R ¹¹ is H, alkoxy or alkenyl, and one or more other R ¹¹ is alkoxy, oximo, amino, aminoxy or acyloxy]. 13. At least three R ¹¹ substituents are each alkoxy, preferably (C ₁ -C ₈ ) alkoxy, more preferably methoxy or ethoxy, and when there are remaining R ¹¹ substituents, (C ₁ -C ₈₎ alkyl, (C ₂ -C ₈₎ alkenyl, aryl or fluoroalkyl composition of claim 12. 14. The polyfunctional organosilicon compound is vinyltrimethoxysilane,
14. The composition according to claim 13, which comprises tetramethoxysilane, methyltriethoxysilane, tetraethoxysilane, methyltrimethoxysilane or a mixture thereof. 15. One R ¹¹ is H or alkenyl and at least two R ¹¹ substituents are each alkoxy, preferably (C ₁ -C ₈ ) alkoxy, more preferably methoxy or ethoxy, and the remaining R 11 ^When there are ¹¹ substituents, (C _1-
C ₈₎ alkyl, aryl or fluoroalkyl composition of claim 12. 16. The polyfunctional organosilicon compound is vinyltrimethoxysilane,
The composition according to claim 15, which comprises vinyltriethoxysilane or a mixture thereof. 17. The filler is fumed silica, hydrophobized fumed silica,
A composition according to claim 3 which comprises carbon black, titanium dioxide, ferric oxide, aluminum oxide, quartz, precipitated silica, hydrophobized precipitated silica, calcium carbonate or mixtures thereof. 18. The composition of claim 3, further comprising a (C ₅ -C ₂₄ ) hydrocarbon fluid. 19. The composition of claim 3, wherein the sealant composition comprises 1 to 40 parts by weight of (C ₅ -C ₂₄ ) hydrocarbon per 100 parts by weight of sealant composition. 20. A first substrate, a second substrate located at a distance from the first substrate, and each of the substrates disposed between the first and second substrates. An assembly comprising a cured mass of the silicone sealant composition of claim 3 which is joined. 21. The assembly of claim 20, wherein at least one of the first and second substrates is a porous substrate. 22. The assembly of claim 20, wherein the porous substrate is a marble, concrete, granite, sandstone or limestone substrate. 23. (i) at least one linear organopolysiloxane polymer having one hydrolyzable silyl end group and one non-hydrolyzable end group per molecule, and two hydrolysable per molecule A linear organopolysiloxane polymer having different silyl end groups, said mixture containing an average of more than 1 and less than 2 hydrolyzable silyl end groups per molecule, and (ii) 2 per molecule. A silicone sealant comprising a moisture curable organopolysiloxane component comprising a mixture or a reaction product thereof with a polyfunctional organosilicon compound containing one or more hydrolyzable groups. 24. Further, (b) a condensation curing catalyst, and (c) a filler,
The sealant composition according to claim 23. 25. The sealant composition comprises 20 to 90 parts by weight of a moisture curable polyorganosiloxane polymer, based on 100 parts by weight of the sealant composition,
25. The sealant composition of claim 24, comprising 0.1 to 10 parts by weight catalyst, and 1 to 10 parts by weight reinforcing filler.