Silicone-based products and their uses

Abstract

When cured, silicone-based materials with improved adhesiveness are provided. These can be used in curable self-adhesive silicone-based products, compositions therefor, and applications in which the self-adhesive products can be used, such as pressure-sensitive adhesives, self-adhesive materials, and / or self-sealing materials, made from the condensation-curable silicone-based compositions. In one specific application, the curable silicone-based materials can be used as a self-sealing layer in inflatable articles such as pneumatic tires.

Description

Technical Field

[0001] The present disclosure relates to improving the adhesiveness of curable self - adhesive silicone - based products such as pressure - sensitive adhesives, self - adhesive materials, and / or self - sealing materials made from condensation - curable silicone - based compositions, compositions therefor, and uses to which such self - adhesive products can be applied.

[0002] The adhesiveness of silicone adhesives, such as curable self - adhesive silicone - based products like pressure - sensitive adhesives, self - adhesive materials, and / or self - sealing materials, is the initial physical adhesiveness to the substrate to be adhered when they first come into contact, i.e., the initial "stickiness" between the two. Adhesiveness is affected by physical adhesive forces that depend very much on (i) interactions via dispersive adhesive forces due to dispersive interactions, such as van der Waals forces and London forces, (ii) capillary interactions (wetting), (iii) mechanical adhesion by interlocking, (iv) diffusion adhesion (interdiffusion), and (v) electrostatic adhesion (charge). However, in the case of silicone adhesives that physically adhere to non - silicone substrates, adhesiveness is mainly governed by dispersive interactions (i), wetting (ii), and interlocking (iii).

[0003] Generally, for example, the success of long - term adhesion between a curable silicone adhesive and the substrate to which it is applied depends on the level of chemical adhesion between them for the formation of subsequent chemical bonds joining the silicone adhesive to the substrate and the cohesiveness of the adhesiveness itself. Cohesiveness is intended to mean its internal bond strength or the ability to hold itself together. Silicone elastomer materials have excellent internal cohesive forces and are resistant to tearing, so they are used in a wide variety of applications.

[0004] Additives referred to as tackifiers are often provided in compositions designed to provide a tacky surface when cured. A tackifier is a chemical compound that is introduced into an adhesive composition and enhances its tack to the substrate to which it adheres. Examples of tackifiers include low molecular weight compounds such as resins with high glass transition temperatures, which increase the initial interaction forces of the adhesive with the substrate. They are thought to function by migrating to the surface of the adhesive and effecting an interaction with the substrate surface. However, due to the very low surface tension of the compositions used, tackifiers cannot easily migrate to the surface of silicone adhesives. Due to the flexibility of the silicone composition, the silicone slowly replaces the tackifier at the surface of the adhesive, and as a result, the adhesive ultimately exhibits the tackiness of the silicone as if no tackifier were present.

[0005] Self - adhesive materials and / or self - sealing materials are utilized in a wide variety of applications. For example, as pressure - sensitive adhesives, as adhesives on patches, and as adhesives in the provision of self - sealing pneumatic tires, even in the case of a significant or complete loss of air pressure in one or more tires, they allow a driver to keep the breaking point safe without stopping their vehicle in often dangerous situations in order to drive the vehicle and install a spare tire.

[0006] Pneumatic tires are widely used on vehicles due to their excellent shock - absorbing properties and ability to provide a comfortable ride. However, they are prone to punctures because they are essentially made from flexible and rubbery materials. When a puncture occurs due to driving over sharp foreign objects such as nails, stones, glass fragments, etc., the high - pressure air inside the tire leaks out, causing it to deflate, and the pneumatic tire cannot function properly. Conventionally, the only solution when a tire is punctured by a foreign object such as a nail has been to replace the original tire with a spare tire, which requires time and effort.

[0007] Self-sealing pneumatic tires are designed to automatically reseal themselves in the event of a puncture by a foreign object such as a nail. Problems not solved regarding the materials used to seal a punctured self-sealing tire include lack of stability over time, lack of effectiveness under extreme operating temperature conditions, and / or manufacturing difficulty.

[0008] To be useful, for example, a self-sealing layer designed to seal a puncture in a tire must be effective over a very wide range of service temperatures and must function over the entire service life of the tire. The self-sealing layer must be able to close the hole when the causative puncturing object (hereinafter referred to as “nail” in this specification) remains in the proper location. Especially in winter, the self-sealing layer must be able to fill the hole and make the tire airtight while removing the nail. The main properties, namely, tensile strength, elongation and crosslink density or storage modulus, have been identified in the industry as being particularly relevant to the function of the self-sealing layer.

[0009] Tensile strength refers to the maximum stress (force per unit area) that a sample of the sealant material can withstand before breaking. Elongation measures the relative increase in the length of a material sample at the break point. Crosslink density is a measure of the density of crosslinks present in the portion of the sealant that has cured to form a three-dimensional crosslinked network as a property of the molecules. The storage modulus of a material is related to the crosslink density of the material. High crosslink density results in a high storage modulus, and conversely, a low crosslinked material exhibits a low storage modulus.

[0010] If the tensile strength of the sealant is too low, the sealant will flow under typical tire service conditions and “blow through” the puncture hole when the puncturing object is removed from the tire, and the hole cannot be sealed.

[0011] The crosslink density of the polymer sealant determines the strength with which the sealant withstands permanent deformation. If the crosslink density or storage modulus of the sealant is too high, the sealant becomes overly resistant to permanent deformation, caps the puncture without forming a tent, and leads to the above results. If the crosslink density or storage modulus is too low, the sealant creeps or flows at high temperatures due to centrifugal force, and there is insufficient sealant under the shoulder portion of the tire. If the crosslink concentration is too low, the fatigue resistance of the sealant composition also decreases. Fatigue resistance is an important requirement, especially for an effective tire sealant, when an object such as a nail enters the tire and the tire is then used for a significant period of time with the nail not removed. Typically, of course, the driver may not even notice the presence of the nail. Due to the periodic contact between the punctured part of the tire and the road, the nail bends back and forth as the tire rotates. While the sealant forms a seal over or around the nail, the sealant itself is continuously stretched and relaxed, and this process can, over time, cause seal failure and loss of airtightness in some cases.

[0012] International Publication No. 2018 / 024857 provides a condensation-curing silicone product that overcomes the above problems when used as a self-sealing layer in a tire, and the composition described therein remains an important requirement because when an object such as a nail enters a tire coated with a self-sealing layer on the inside, the material within the layer needs to be sufficiently adhesive to immediately adhere to the nail and form a tent-like structure around it, but there is a possibility that it may not be sufficiently adhesive. This initial adhesion of the sealant to the nail helps preserve the air barrier during puncture and also causes the sealant to be drawn into the puncture hole by the nail when the nail is removed.

[0013] The following disclosure provides a condensation-curing self-adhesive silicone-based product having improved adhesion of the silicone-based product without using an adhesion promoter. In a first embodiment, a condensation-curable silicone-based composition, (i) An organopolysiloxane-based polymer having two or more silicon-bonded hydroxyl groups or hydrolyzable groups per molecule and a viscosity of 30,000 mPa·s to 200,000 mPa·s at 23°C, and (ii) A crosslinking agent containing a silyl-functional polymer having at least two silyl groups, each silyl group containing at least two hydrolyzable groups, and (iii) A condensation catalyst selected from the group of titanates and / or zirconates, and optionally (iv) A reinforcing filler or a non-reinforcing filler, and provides a self-adhesive silicone-based product having an absolute adhesiveness of (≧) 1.025 or more when cured, wherein the absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)]. The absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)].

[0014] In a second embodiment, there is provided a condensation-curable self-adhesive silicone-based product obtained by curing a condensation-curable silicone-based composition, (i) An organopolysiloxane-based polymer having two or more silicon-bonded hydroxyl groups or hydrolyzable groups per molecule and a viscosity of 30,000 mPa·s to 200,000 mPa·s at 23°C, and (ii) A crosslinking agent containing a silyl-functional polymer having at least two silyl groups, each silyl group containing at least two hydrolyzable groups, and (iii) A condensation catalyst selected from the group of titanates and / or zirconates, and optionally (iv) A reinforcing filler or a non-reinforcing filler, and provides a condensation-curable self-adhesive silicone-based product having an absolute adhesiveness of ≧ 1.025, wherein the absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)]. The absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)].

[0015] The aforementioned condensation-curable self-adhesive silicone-based product exhibits high adhesiveness maintained over a long period of time and is thus useful for many potential applications such as pressure-sensitive adhesives, patches, and / or anti-puncture materials for inflatable articles such as tires.

[0016] This specification provides an inflatable article having a self-sealing layer that includes the condensation-curing self-adhesive silicone-based product. The above-described condensation-curable silicone-based composition for providing the product has a viscosity that enables it to be incorporated into an inflatable article, such as a tire, during a tire construction process when uncured, and the resulting cured product can function as a self-sealing layer so as to flow into and seal a puncture in the inflatable article, such as a pneumatic tire.

[0017] In the case of a tire, during use, a pneumatic tire having an outer surface or tread surface and an inner surface is mounted on a wheel rim. When assembled, the inner surface of the tire and the wheel rim define an internal annular cavity intended to be inflated to support the load on the tire. Such a pneumatic tire is prone to puncture because it is essentially made of a flexible and pliable material containing rubber. When a puncture occurs due to running over sharp foreign objects such as nails, stones, or glass pieces, if it cannot be prevented, the high-pressure air in the internal annular cavity leaks, causing shrinkage and the pneumatic tire cannot function properly. The layer of the above-described condensation-curing self-adhesive silicone-based product can prevent or at least minimize this shrinkage effect by sealing the puncture.

[0018] The above condensation-curing silicone-based composition is generally stored in two or more parts before use. In the case of a two-part composition, one part may contain the polymer (i) and the filler (iv) if present, and the cross-linking agent (ii) and the catalyst (iii) are kept separated from the filler (iv) in the curing agent. This is because the filler (iv) is utilized to provide the moisture necessary to activate the condensation curing in most of the product. In the presence of such an amount of moisture during storage before use, the alkyl titanate catalyst may be inactivated as a result of being completely hydrolyzed to tetrahydroxytitanate. The two parts can be mixed in any suitable ratio, for example, base part:curing agent of 15:1 to 1:1, or 12:1 to 1:1, preferably 10:1 to 1:1. Typically, the ratio of the two parts depends on the relative amounts of the components contained in each part. The above condensation-curing silicone-based composition is generally designed to cure and / or be curable at room temperature.

[0019] The polymer (i) is at least one organopolysiloxane-based polymer having two or more silicon-bonded hydroxyl groups or hydrolyzable groups per molecule and having a viscosity of 30,000 mPa·s to 200,000 mPa·s at 23°C. Any suitable organopolysiloxane-based polymer including polydialkylsiloxane, alkylphenylsiloxane, siloxane copolymer, or siloxane / organic copolymer, such as polyether, acrylate, or polyisobutylene, may be utilized. In one alternative, the polymer (i) is a polysiloxane-based polymer containing at least two terminal silanol (Si-OH) containing groups. Examples of suitable silanol-containing groups include -Si(OH)3, -(R a )Si(OH)2, -(R a )2Si(OH), or -(R a )2Si-R c -SiR d p (OH) 3-p [wherein each R arepresents independently a monovalent hydrocarbyl group, for example, an alkyl group, especially one having 1 to 8 carbon atoms (preferably methyl), and each R d group is independently an alkyl group, where the alkyl group preferably has up to 6 carbon atoms, and R c is a divalent hydrocarbon group having up to 12 carbon atoms, which can be intervened by one or more siloxane spacers having up to 6 silicon atoms, such as ethylene or propylene, and p is a value of 0, 1, or 2].

[0020] Preferably, the polymer (i) has the general formula X 3 -A-X 1 (1) [wherein X 3 and X 1 are independently selected from siloxane groups having hydroxyl-containing groups at the terminals, and A is a siloxane-based polymer chain containing siloxane groups and optionally organic groups, or a siloxane polymer chain].

[0021] Examples of the silanol or hydroxyl terminal group X 3 or X 1 include -Si(OH)3, -(R a )Si(OH)2, -(R a )2Si(OH), or -(R a )2Si-R c -Si(R d ) p (OH) 3-p as defined above. Preferably, the X 3 and / or X 1 terminal groups are hydroxydialkyl terminals, for example, hydroxydimethyl terminals.

[0022] Examples of suitable siloxane groups in the polymer chain A of formula (I) are the siloxane groups constituting the polydiorganosiloxane chain. Therefore, the polymer chain A preferably has the formula (2) -(R 5 s SiO (4-s) / 2 )- (2) [In the formula, each R 5 is independently an organic group such as a hydrocarbyl group having 1 to 10 carbon atoms, optionally substituted with one or more halogen groups such as chlorine or fluorine, s is 0, 1, or 2, and typically the average value of s is about 2] and includes a siloxane unit. As specific examples of the group R 5 , there are a methyl group, an ethyl group, a propyl group, a butyl group, a vinyl group, a cyclohexyl group, a phenyl group, a tolyl group, a propyl group substituted with chlorine or fluorine, for example, a 3,3,3-trifluoropropyl group, a chlorophenyl group, a β-(perfluorobutyl)ethyl group or a chlorocyclohexyl group. Preferably, at least some, preferably substantially all, of the groups R 5 are methyl.

[0023] The polymer (i) of the above type has a viscosity of 30,000 to 200,000 mPa·s, or 45,000 to 175,000 mPa·s, or 50,000 to 150,000 mPa·s at 23°C, which is measured using a Brookfield cone and plate viscometer (RV DIII) with the most appropriate spindle for the relevant viscosity at 0.1 to 5 rpm, for example, a CP-51 or CP-52 spindle.

[0024] Accordingly, a preferred polysiloxane containing the unit of formula (2) is a polydiorganosiloxane having a terminal, silicon-bonded hydroxyl group, otherwise referred to as a silanol-containing terminal group (Si-OH). The polydiorganosiloxane may be a homopolymer or a copolymer. A mixture of different polydiorganosiloxanes having silanol-containing terminal groups is also suitable.

[0025] Furthermore, the composition has one Si-hydroxyl (silanol)-containing terminal group, for example, one -Si(OH)3, -(R a )Si(OH)2, -(R a ) 2 Si(OH), or -(R a )2Si-R c -SiRd p (OH) 3-p For example, it may contain a polymer having a dialkyl hydroxy end group and one non-reactive end group, for example, a trialkyl end, i.e., a trimethyl end group. Thus, the polymer (i) may further include a polydiorganosiloxane that is partially dialkyl hydroxy terminated and partially trialkyl terminated. By including such additional polymers, the modulus of elasticity of the product obtained after curing can be reduced and / or the adhesiveness to a substrate that is difficult to adhere to can be improved. Such additional polymers (i) can have a viscosity similar to that of the aforementioned ones.

[0026] According to the present invention, the polymer chain A can alternatively be a copolymer with an organic polymer such as polyether, acrylate, and polyisobutylene. In the case of polyether, the polymer chain is based on polyoxyalkylene units. Such polyoxyalkylene units preferably have an average formula (-C n H 2n -O-) y [wherein n is an integer from 2 to 4 and y is an integer of at least 4] represented by a repeating oxyalkylene unit (-C n H 2n -O-) to form a linear polymer mainly composed of oxyalkylene. The number average molecular weight of each polyoxyalkylene polymer block or polymer may be in the range of about 300 g / mol to about 10,000 g / mol, but may also be of higher molecular weight. Further, the oxyalkylene units do not have to be the same throughout the polyoxyalkylene monomer and may vary from unit to unit. The polyoxyalkylene block can be composed of, for example, oxyethylene units (-C2H4-O-), oxypropylene units (-C3H6-O-); or oxybutylene units (-C4H8-O-), or a mixed unit thereof.

[0027] As other polyoxyalkylene units, for example, a structural unit -[-R e -O-(-R f -O-)w -Pn-CR g 2-Pn-O-(-R f -O-) q -R e - [wherein, Pn is a 1,4-phenylene group, and each R e is the same or different and is a divalent hydrocarbon group having 2 to 8 carbon atoms, and each R f is the same or different and is an ethylene group or a propylene group, and each R g is the same or different and is a hydrogen atom or a methyl group, and each of the subscripts w and q is a positive integer in the range of 3 to 30] can be mentioned.

[0028] For the purposes of this application, "substituted" means that one or more hydrogen atoms in a hydrocarbon group are replaced by another substituent. Examples of such substituents include halogen atoms such as chlorine, fluorine, bromine and iodine; halogen atom-containing groups such as chloromethyl group, perfluorobutyl group, trifluoroethyl group, and nonafluorohexyl group; oxygen atom; oxygen atom-containing groups such as (meth)acrylic group and carboxyl group; nitrogen atom; nitrogen atom-containing groups such as amino functional group, amide functional group, and cyano functional group; sulfur atom; and sulfur atom-containing groups such as mercapto group, but are not limited thereto.

[0029] In one embodiment, an additional polydiorganosiloxane polymer (ia) may be utilized. The additional polydiorganosiloxane polymer (ia) may have a structure similar to that of the polymer (i), but has a viscosity outside the viscosity range of the polymer (i). One alternative additional polydiorganosiloxane polymer (ia) has a viscosity greater than (>) 200,000 mPa·s at 23°C. The additional polydiorganosiloxane polymer (ia) may be present in an amount of up to 70 weight percent (wt.%) of the total weight of the polymer (i) and the additional polymer (ia), or up to 50 weight percent of the total weight of the polymer (i) and the additional polymer (ia), or up to 30 weight percent of the total weight of the polymer (i) and the additional polymer (ia), or up to 10 weight percent of the total weight of the polymer (i) and the additional polymer (ia).

[0030] Polymer (i) + (ia) is preferably present in the composition in an amount of 60% to 90% by weight, or 70% to 90% by weight of the composition.

[0031] The crosslinking agent (ii) is a silyl-functional polymer having at least two silyl groups per molecule, each silyl group containing at least two hydrolyzable groups.

[0032] For the purposes of the disclosure herein, a silyl-functional polymer is a silyl-functional polymer containing two or more silyl groups, each silyl group containing at least two hydrolyzable groups. Thus, a disilyl-functional molecule contains two silicon atoms each having at least two hydrolyzable groups, these silicon atoms being separated by an organic or siloxane polymer backbone chain. Typically, the silyl groups on the disilyl-functional molecule are end groups.

[0033] To avoid misunderstanding, the crosslinking agent is not a disilane in which two silicon atoms are directly bonded to each other.

[0034] Examples of the hydrolyzable groups bonded to the silyl groups in the crosslinking agent (ii) include acyloxy groups (e.g., acetoxy group, octanoyloxy group, and benzoyloxy group); ketoximino groups (e.g., dimethylketoximo group and isobutylketoximino group); alkoxy groups (e.g., methoxy group, ethoxy group, and propoxy group), and alkenyloxy groups (e.g., isopropenyloxy group and 1-ethyl-2-methylvinyloxy group). There are at least two hydrolyzable groups bonded to each silyl group, or three hydrolyzable groups per silyl. One alternative hydrolyzable group for each is an alkoxy group.

[0035] Suitable polymer crosslinking agent (ii) may have a polymer backbone chain chemical structure similar to any of those described for polymer chain A represented by the above formula (1). However, for crosslinking agent (ii), the polymer backbone chain can be a silicone backbone chain, an organic backbone chain, or a silicone / organic copolymer backbone chain. In the case of such siloxane and / or organic-based crosslinking agents, the molecular structure can be linear, branched, cyclic, or macromolecular, that is, the silicone or organic polymer chain having an alkoxy functional terminal group includes polydimethylsiloxane having at least one trialkoxy terminal, and the alkoxy group thereof may be a methoxy group or an ethoxy group.

[0036] In the case of siloxane-based crosslinking agent (ii), the viscosity of the crosslinking agent is in the range of 0.5 mPa·s to 80,000 mPa·s at 23 °C as measured (in the same manner as polymer (i)) using a Brookfield cone plate viscometer (RV DIII) with a cone plate. Crosslinking agent (ii) may further contain a silyl-functional molecule having at least two silyl groups, and at least one silyl group contains one hydrolyzable group. Any of the above hydrolyzable groups is suitable, but the hydrolyzable group is an alkoxy group, and thus the terminal silyl group is -R a Si(OR b )2, -Si(OR b )3, -R a 2SiOR b , or -(R a )2Si-R c -SiR d p (OR b ) 3-p [wherein each R a independently represents a monovalent hydrocarbon group, for example, an alkyl group having particularly 1 to 8 carbon atoms (preferably a methyl group), and each R b and R d groups are independently alkyl groups having a maximum of 6 carbon atoms, and R c is a divalent hydrocarbon group that can be intervened by one or more siloxane spacers having a maximum of 6 silicon atoms, and p is a value of 0, 1, or 2] and may have formulas such as. For example, Rc can be an ethylene group or a propylene group, etc. Typically, each terminal silyl group has two or three alkoxy groups.

[0037] In one alternative, each silyl group is a trialkoxysilyl group. When the silyl group is a dialkoxy group or a monoalkoxy group, the remaining groups are alkyl groups and / or aryl groups, or alkyl groups having 1 to 6 carbons, or methyl and / or ethyl, or methyl.

[0038] In one embodiment, the terminal group has the following formula -(R a )2Si-R c -SiR d q (OR b ) 3-q [wherein, R a , R c and R d are as previously defined, R b is an alkyl group having 1 to 6 carbons, for example, methyl, q is 0 or 1, or q is 0].

[0039] In one embodiment, the crosslinking agent (ii) is a disilyl-functional polymer, that is, it contains two silyl groups, each having the formula (4): (R 4 O) m (Y 1 ) 3-m -Si(CH2) x -((NHCH2CH2) t -Q(CH2) x ) n -Si(OR 4 ) m (Y 1 ) 3-m (4) [wherein, R 4 is a C 1-10 alkyl group, Y 1 is an alkyl group containing 1 to 8 carbons, Q is a chemical group containing a heteroatom having a lone pair of electrons, for example, an amine, an N-alkylamine or a urea, each x is an integer from 1 to 6, t is 0 or 1, each m is independently 1, 2 or 3, and n is 0 or 1], and may be a polymer containing at least two hydrolyzable groups such as those described by

[0040] Examples of the disilyl polymer crosslinking agent (ii) having a silicone or organic polymer chain with an alkoxy functional end group include 1,6-bis(trimethoxysilyl)hexane (alternatively known as hexamethoxydisilylhexane HMSH), polydimethylsiloxane having at least two trialkoxy ends where the alkoxy group can be a methoxy group or an ethoxy group or a bis(trialkoxysilylalkyl)amine, bis(dialkoxysilylalkyl)amine, bis(trialkoxysilylalkyl)N-alkylamine, bis(dialkoxysilylalkyl)N-alkylamine, bis(trialkoxysilylalkyl)urea, bis(dialkoxysilylalkyl)urea, bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine, bis(4-trimethoxysilylbutyl)amine, bis(4-triethoxysilylbutyl)amine, bis(3-trimethoxysilylpropyl)N-methylamine, bis(3-triethoxysilylpropyl)N-methylamine, bis(4-trimethoxysilylbutyl)N-methylamine, bis(4-triethoxysilylbutyl)N-methylamine, bis(3-trimethoxysilylpropyl)urea, bis(3-triethoxysilylpropyl)urea, bis(4-trimethoxysilylbutyl)urea, bis(4-triethoxysilylbutyl)urea, bis(3-dimethoxymethylsilylpropyl)amine, bis(3-diethoxymethylsilylpropyl)amine, bis(4-dimethoxymethylsilylbutyl)amine, bis(4-diethoxymethylsilylbutyl)amine, bis(3-dimethoxymethylsilylpropyl)N-methylamine, bis(3-diethoxymethylsilylpropyl)N-methylamine, bis(4-dimethoxymethylsilylbutyl)N-methylamine, bis(4-diethoxymethylsilylbutyl)N-methylamine, bis(3-dimethoxymethylsilylpropyl)urea, bis(3-diethoxymethylsilylpropyl)urea, bis(4-dimethoxymethylsilylbutyl)urea, bis(4-diethoxymethylsilylbutyl)urea, bis(3-dimethoxyethylsilylpropyl)amine, bis(3-diethoxyethylsilylpropyl)amine, bis(4-dimethoxyethylsilylbutyl)amine,Bis(4-diethoxyethylsilylbutyl)amine, bis(3-dimethoxyethylsilylpropyl)N-methylamine, bis(3-diethoxyethylsilylpropyl)N-methylamine, bis(4-dimethoxyethylsilylbutyl)N-methylamine, bis(4-diethoxyethylsilylbutyl)N-methylamine, bis(3-dimethoxyethylsilylpropyl)urea, bis(3-diethoxyethylsilylpropyl)urea, bis(4-dimethoxyethylsilylbutyl)urea and / or bis(4-diethoxyethylsilylbutyl)urea; bis(triethoxysilylpropyl)amine, bis(trimethoxysilylpropyl)amine, bis(trimethoxysilylpropyl)urea, bis(triethoxysilylpropyl)urea, bis(diethoxymethylsilylpropyl)N-methylamine; di- or trialkoxysilyl-terminated polydialkylsiloxane, di- or trialkoxysilyl-terminated polyarylalkylsiloxane, di- or trialkoxysilyl-terminated polypropylene oxide, polyurethane, polyacrylate; polyisobutylene; di- or triacetoxysilyl-terminated polydialkyl; polyarylalkylsiloxane; di- or trioximinosilyl-terminated polydialkyl; polyarylalkylsiloxane; di- or triacetonoxy-terminated polydialkyl or polyarylalkyl. The crosslinking agent (ii) used may also include any combination of two or more of the above.

[0041] The crosslinking agent (ii) is preferably present in the composition in an amount of 1.0% to 10.0% by weight of the composition, or in an amount of 1% to 7.5% by weight.

[0042] In one embodiment, the molar ratio of all silanol groups (silicon-bonded hydroxyl groups) to all hydrolyzable groups in the composition is ≧0.5:1, or ≧1:1, or ≧2:1, or 2:1 to 4:1.

[0043] The total silicon-bonded hydroxyl (Si-OH) molar content is calculated for 100 g of the mixed formulation. The total silicon-bonded hydroxyl molar content for a polymer is equal to the amount of hydroxyl-containing polymer in 100 g of the mixed product (in g units), divided by the number average molecular weight (Mn) of the polymer, and multiplied by the average number of hydroxyl functional groups present in the polymer (typically 2). When several hydroxyl-functional polymers are present in the formulation, the sum of the molar contents of each polymer constitutes the total silicon-bonded hydroxyl (Si-OH) molar content in the formulation.

[0044] The total hydrolyzable group molar content is calculated for 100 g of the mixed formulation. The molar content of hydrolyzable groups for a substance is equal to the amount of molecules containing hydrolyzable groups in 100 g of the mixed product (in grams (g) units), divided by the molecular weight of the molecule or, in the case of a polymer molecule, the number average molecular weight (Mn), and multiplied by the average number of hydrolyzable functional groups present in the molecule. The sum of the molar contents of each molecule or polymer constitutes the total molar content of hydrolyzable groups in the formulation.

[0045] Next, the molar ratio of the total silicon-bonded hydroxyl groups to the total hydrolyzable groups is calculated by dividing the total molar content of the total silicon-bonded hydroxyl (Si-OH) groups by the total molar content of the hydrolyzable groups, or can be expressed as a ratio.

[0046] The number average molecular weight (Mn) and weight average molecular weight (Mw) of the silicone can also be determined by gel permeation chromatography (GPC). This technique is a standard technique and values for Mw (weight average), Mn (number average) and polydispersity index (PI) [where PI = Mw / Mn] are obtained.

[0047] The Mn values provided in this application are determined by GPC and represent typical values for the polymers used. When not provided by GPC, Mn can also be obtained from calculations based on the dynamic viscosity of the above polymers.

[0048] The composition further comprises a condensation catalyst. Thereby, the rate at which the composition cures is increased. The catalyst selected for inclusion in the composition depends on the required curing rate.

[0049] The catalyst is either a titanate catalyst or a zirconate catalyst. The titanate-based catalyst and / or zirconate-based catalyst has the general formula Ti[OR 22 4 or Zr[OR 22 4 [wherein each R 22 may be the same or different and represents a monovalent, primary, secondary, or tertiary aliphatic hydrocarbon group which may be linear or branched and have 1 to 10 carbon atoms]. Optionally, the titanate and / or zirconate may contain a partially unsaturated group. Examples of R 22 include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, and branched secondary alkyl groups such as 2,4-dimethyl-3-pentyl. Alternatively, when each R 22 is the same, R 22 is an isopropyl group, a branched secondary alkyl group, or a tertiary alkyl group, particularly tertiary butyl. In one alternative, the catalyst is a titanate. Examples of suitable titanates include tetra n-butyl titanate, tetra t-butyl titanate, titanium tetrabutoxide, and tetraisopropyl titanate. Examples of suitable zirconates include tetra n-propyl zirconate, tetra n-butyl zirconate, and zirconium diethyl citrate.

[0050] Alternatively, the titanate and / or zirconate may be chelated. Chelation may be by any suitable chelating agent, such as alkyl acetylacetonate, for example methyl or ethyl acetylacetonate. Alternatively, the titanate may be a monoalkoxytitanate that provides three chelating agents, such as 2-propanolato, tris isooctadecanoato titanate, or diisopropyl diethylacetoacetate titanate.

[0051] The catalyst (iii) is preferably present in the composition in an amount of 0.01% to 5.0% by weight, or 0.05% to 3.0% by weight of the composition.

[0052] The compositions of the present specification may incorporate reinforcing fillers and / or non-reinforcing fillers (iv) or combinations thereof. Examples of finely divided reinforcing fillers include fumed silica and precipitated silica with a large surface area such as rice husk ash, and to some extent calcium carbonate. Examples of further finely divided non-reinforcing fillers include ground quartz, diatomaceous earth, barium sulfate, iron oxide, titanium dioxide, carbon black, glass beads, hollow glass beads, talc, wollastonite. Other fillers that may be used alone or in combination with the above fillers include carbon nanotubes, such as multi-walled carbon nanotubes, carbon fibers, aluminite, calcium sulfate (anhydrite), gypsum, calcium sulfate, barium titanate, magnesium carbonate, kaolin, aluminum trihydroxide, clays such as magnesium hydroxide (hydrotalcite), graphite, diamond, copper carbonate (e.g., malachite), nickel carbonate (e.g., zarachite), barium carbonate (e.g., witherite), and / or strontium carbonate (e.g., strontianite). Examples of anhydrous inorganic fillers include onyx; metal oxides such as aluminum trihydrate, aluminum oxide, beryllium oxide, magnesium oxide, zinc oxide; nitrides such as aluminum nitride and boron nitride; carbides such as silicon carbide and tungsten carbide, and combinations thereof exemplified thereby.

[0053] Further examples of fillers include aluminum oxide, the cancrinite group; the garnet group; aluminosilicates; cyclic silicates; chain silicates; and silicates from the group consisting of layered silicates. The cancrinite group includes, but is not limited to, silicate minerals such as forsterite and Mg2SiO4. The garnet group includes red garnet; Mg3Al2Si3O 12 ; green garnet; and Ca2Al2Si3O 12including, but not limited to, crushed silicate minerals such as. Aluminosilicates include, but are not limited to, kyanite; Al2SiO5; mullite; 3Al2O3.2SiO2; sillimanite; and crushed silicate minerals such as Al2SiO5. The cyclic silicate group includes, but is not limited to, cordierite and Al3(Mg, Fe)2[Si4AlO 18 and other silicate ores. The chain silicate group includes, but is not limited to, crushed silicate minerals such as wollastonite and Ca[SiO3]. Phyllosilicates include mica; K2AI 14 [Si6Al2O 20 (OH)4; pyrophyllite; Al4[Si8O 20 (OH)4; talc, Mg6[Si8O 20 (OH)4; serpentine, such as asbestos; kaolinite; Al4[Si4O 10 (OH)8; and vermiculite and other silicate minerals, but are not limited to these. Any combination of two or more of the above fillers may be used.

[0054] When present in a preferred embodiment, the filler used is selected from fumed silica and precipitated silica, calcium carbonate, carbon black, hollow glass beads and / or carbon nanotubes, such as multi-walled carbon nanotubes, and mixtures thereof.

[0055] Any filler (iv) is preferably present in the composition in an amount of 10% to 40% by weight, or 10% to 25% by weight, or 10% to 20% by weight of the composition. When present, the filler may be a hydrous filler, i.e., it cannot be anhydrous. Optionally, the quantitative amount of water present in the filler can be determined by extraction of water from a sample of the filler used in the compositions of the present inventors using the test method of ISO787 2:1981.

[0056] In one embodiment, when present, the molar ratio of the catalyst M-OR function (where M is titanium or zirconium and R is an alkyl group or a chelate group) determined according to ISO 787-2:1981 to the total of the moisture present in the filler and all silicon-bonded hydroxyls (silanol groups) is from 0.01:1 to 0.6:1. In one embodiment, R is as defined above R 22 is.

[0057] Filler treatment agent Any reinforcing and / or non-reinforcing filler (iv), when present, can be surface-treated with a treatment agent. Treatment agents and treatment methods are known in the art. Surface treatment of the filler is typically carried out using, for example, fatty acid esters such as fatty acids or stearates, or organosilanes, organosiloxanes, or organosilazanes, such as hexaalkyldisilazanes or short-chain siloxane diols. Generally, the surface treatment makes the filler hydrophobic and thus facilitates the handling and availability of a homogeneous mixture with other components in the composition. Silanes, for example, R 7 e Si(OR 6 ) 4-e [wherein R 7 is a substituted or unsubstituted monovalent hydrocarbon group having 6 to 20 carbon atoms, for example, an alkyl group such as hexyl, octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, and an aralkyl group such as benzyl and phenylethyl, an alkyl group having 6 to 20 carbon atoms being preferred, R 6 is an alkyl group having 1 to 6 carbon atoms, and the letter e is equal to 1, 2, or 3] may also be used as a treatment agent for the filler.

[0058] The presence of the filler is determined by the end use. For example, in the case of the use of a product / composition for a self-sealing inflatable article such as a tire, the filler (iv) is most likely to be present to enhance the physical properties of the product, i.e., to provide tensile strength, tear resistance, and in addition to prevent sagging during application.

[0059] In addition to the above components, optional components may be incorporated into the composition to the extent that the object of the present invention is achieved.

[0060] Examples of optional components include heat resistance-imparting agents, cold resistance-imparting agents, flame retardants, thixotropy-imparting agents, pigments, surfactants, fluxes, acid acceptors, protective agents, UV stabilizers, antioxidants, ozone degradation inhibitors, corrosion-resistant additives, dyes, and biocides, or any suitable combination thereof.

[0061] Adhesion promoter Suitable adhesion promoters are represented by the following formula R 14 h Si(OR 15 ) (4-h) , [wherein the subscript h is 1, 2, or 3, or h is 3], and may include alkoxysilanes. Each R 14 is independently a monovalent organic functional group. R 14 is an epoxy functional group such as a glycidoxypropyl group or an (epoxycyclohexyl)ethyl group, an amino functional group such as an aminoethylaminopropyl group or an aminopropyl group, a methacryloxypropyl group, a mercapto functional group such as a mercaptopropyl group, or an unsaturated organic group. Each R 15 is independently an unsubstituted saturated hydrocarbon group having at least 1 carbon atom. R 15 may have 1 to 4 carbon atoms, or 1 to 2 carbon atoms. Examples of R 15 include methyl, ethyl, n-propyl, and isopropyl.

[0062] Examples of suitable adhesion promoters include glycidoxypropyltrimethoxysilane and combinations of glycidoxypropyltrimethoxysilane with aluminum chelates or zirconium chelates. Examples of adhesion promoters can be found in U.S. Patent Nos. 4,087,585 and 5,194,649. The curable composition, if present, may contain from 0.01 to 2% by weight, or from 0.05 to 2% by weight, or from 0.1 to 1% by weight of an adhesion promoter, based on the weight of the composition. Preferably, the hydrolysis rate of the adhesion promoter should be slower than that of the crosslinking agent so as to be more favorable for the diffusion of molecules into the substrate than for incorporation into the product network.

[0063] Surfactant Suitable surfactants include silicone polyethers, ethylene oxide polymers, propylene oxide polymers, copolymers of ethylene oxide and propylene oxide, other nonionic surfactants, and combinations thereof. The composition may contain up to 0.05% by weight of a surfactant, based on the weight of the composition.

[0064] Fluxing agent The composition may contain up to 2% by weight of a fluxing agent, based on the weight of the composition. Molecules containing chemically active functional groups such as carboxylic acids and amines can be used as fluxing agents. Such fluxing agents include aliphatic acids such as succinic acid, abietic acid, oleic acid, and adipic acid; aromatic acids such as benzoic acid; aliphatic amines and their derivatives such as triethanolamine, hydrochlorides of amines, and hydrobromides of amines. Fluxing agents are known in the art and are commercially available.

[0065] Acid acceptor Suitable acid acceptors include magnesium oxide, calcium oxide, and combinations thereof. The composition, if appropriate, may contain up to 2% by weight of an acid acceptor, based on the weight of the composition.

[0066] Corrosion-resistant additives such as nitrogen / sulfur-containing heterocyclic compounds having a triazole structure, a thiadiazole structure, a benzotriazole structure, a mercaptothiozole structure, a mercaptobenzothiazole structure, or a benzimidazole structure. In the case of a two-component composition, the A part or the base part may contain 60 to 90% by weight of polymer (i) and 10 to 40% by weight of filler (iv), or 70 to 90% by weight of polymer (i) and 10 to 30% by weight of filler (iv), or 75 to 90% by weight of polymer (i) and, if present, 10 to 25% by weight of filler (iv). This is adjusted when any other components are included in part A.

[0067] In one embodiment, the product is (i) An organopolysiloxane-based polymer having two or more silicon-bonded hydroxyl groups or hydrolyzable groups per molecule, in an amount of 60% to 90% by weight of the composition, or 70% to 90% by weight of the composition, and having a viscosity of 30,000 mPa·s to 200,000 mPa·s at 23°C, and (ii) A crosslinking agent containing a silyl-functional polymer having at least two silyl groups, each silyl group containing at least two hydrolyzable groups, in an amount of 1.0% to 10.0% by weight of the composition, or 1% to 7.5% by weight of the composition, and (iii) A condensation catalyst selected from the group of titanates and / or zirconates, in an amount of 0.01% to 5.0% by weight of the composition, or 0.05% to 3.0% by weight of the composition, and optionally A reinforcing or non-reinforcing filler (iv) in an amount of 10% to 40% by weight of the composition, or 10% to 25% by weight of the composition, or 10% to 20% by weight of the composition, and the total weight percentage of the composition is 100% by weight, and a composition having an absolute adhesiveness of ≧1.025 is obtained when cured, Absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)] or = -[F-] / [F+].

[0068] As described above in this specification, the compositions described above in this specification are typically made from condensation-curing silicone-based compositions that are stored in two parts. The two-part composition may be mixed using any suitable standard two-part mixing device by a dynamic or static mixer and, if desired, is metered and dispensed from the device for use in the intended application.

[0069] In one embodiment, the composition is stored in two parts, and the parts can be divided as follows a) Polymer (i) and crosslinking agent (ii) in one part, polymer (i) and catalyst (iii) in the other part, b) Crosslinking agent (ii) in one part, polymer (i) and catalyst (iii) in the other part, or c) When using more than one polymer (i), the first polymer (i) and crosslinking agent (ii) in one part, the second polymer (i) and catalyst (iii) in the other part, d) Polymer (i) in one part, crosslinking agent (ii) and catalyst (iii) in the other part.

[0070] As described above, when the filler (iv) is present, the filler (iv) and the catalyst (iii) are separated and held during storage. Typically, when present, the filler (iv) is mixed with the polymer (i) in the base part which may also contain other additives, and the catalyst (iii) is in the curing agent part together with the crosslinking agent (ii).

[0071] The condensation-curing self-adhesive silicone-based product obtained from the condensation-curing silicone-based composition described above in this specification needs to have an absolute adhesiveness > 1.025, Absolute adhesiveness = -[adhesive strength (F-)] / [hardness strength (F+)] or = -[F-] / [F+].

[0072] Absolute adhesiveness is a measure of the ratio between the adhesive strength (F-) and the hardness strength (F+), determined using an appropriate texture analyzer. The texture analyzer used in the examples herein was a Stable Micro Systems TA XT+ with a 1 / 2 inch (1.27 cm) hemispherical probe made of polyester, set to penetrate 5 mm of the sample at a speed of 0.1 mm / second. The hardness strength (F+) is the maximum "strength" measured during penetration of the probe, and the adhesive strength (F-) is the maximum "strength" measured during removal of the probe. The adhesiveness of a material is affected by the time and pressure of contact. Longer time or higher pressure will result in higher adhesiveness. Both time and surface area are constant during our measurements, but the force applied, and thus the pressure applied, will depend on the hardness of the sample. When tested, harder materials apply a higher pressure to the measuring probe and may "artificially" increase the measured strength (F-) when the probe is removed from the sample. To account for this hardness effect, we define absolute adhesiveness as the ratio between the adhesive strength (F-) and the hardness strength (F+). Taking this into account, we rely on the measurement of absolute adhesiveness using the formula provided above. A cured material having an absolute adhesiveness value greater than 1, or ≥1.025, is characteristic of a material showing an adhesive strength [F-] higher than the hardness strength [F+], which is best achieved by the product of the above composition comprising a polymer (i) having a viscosity in the range of 30,000 - 200,000 mPa·s at 23°C, or 45,000 - 175,000 mPa·s at 23°C, or 50,000 - 150,000 mPa·s at 23°C, measured using an appropriate spindle, such as a CP - 51 or CP - 52 spindle, at 0.1 - 5 rpm with a Brookfield cone plate viscometer (RV DIII).

[0073] The condensation-curing self-adhesive silicone-based product obtained from the condensation-curing silicone-based composition described above in this specification can be used as a pressure-sensitive adhesive, a self-adhesive material, and / or a self-sealing material, for example, in an adhesive on a patch or as such, and in the provision of an inflatable article provided with a self-sealing layer containing the condensation-curing self-adhesive silicone-based product.

[0074] In one embodiment, the condensation-curing self-adhesive silicone-based product is utilized as a puncture self-sealing layer in an inflatable article. In one embodiment, the inflatable article is a self-sealing pneumatic tire. The puncture self-sealing layer is provided on the inner surface of the tire so that, for example, when a puncture occurs due to running over a sharp foreign object such as a nail, a stone, or a piece of glass, it can seal a puncture hole or the like where the product of this specification was made, and the vehicle can continue to run despite a substantial or complete loss of pressure in one or more tires. Thereby, for example, in often dangerous situations, it is not necessary to stop to install a spare tire and it becomes possible to run to the breaking point.

[0075] For practical use of the condensation-curing self-adhesive silicone-based product as a puncture self-sealing layer for tires, it must be formulated so that it can be easily and practically applied to the tire or article to which the condensation-curing self-adhesive silicone-based product is to be used. One method of applying the condensation-curing silicone-based composition described in this specification inside a tire includes the steps of mixing the composition and spraying it inside the tire while the tire is rotating. During tire rotation, some curing of the composition occurs by mixing the two parts of the composition, and a uniform seamless coating that can withstand running and puddling is obtained.

[0076] The condensation-curing silicone-based composition described in this specification is typically suitable for application to post-vulcanized tires because it does not require heat for curing.

[0077] In the present invention, the condensation-curing silicone-based composition is provided as a two-component composition. The two-component composition is mixed in a suitable mixing / charging unit, and the mixed composition is immediately applied to the surface of the target substrate (tire). The composition after mixing is designed to have sufficient green strength to adhere to the inner surface of the tire and cures after several hours.

[0078] Typically, the two-component condensation-curing silicone-based composition is applied in an uncured state and cures immediately upon mixing and adhering onto the substrate tire surface. Depending on the end use, as discussed below, it has a cured thickness of 0.25 to 10 mm, or 0.5 mm to 10 mm, or 1 to 5 mm. After mutual mixing and before curing, the condensation-curing silicone-based composition can be applied onto the substrate using a suitable dispenser such as, for example, a curtain coater, spray device die coater, dip coater, extrusion coater, knife coater, and screen coater. As a result, when curing is formed, a coating is provided on the substrate.

[0079] The required thickness and pressure requirements for the self-sealing layer will vary depending on the end use of the tire involved. Thereby, for example, in the case of a passenger car type tire, it can have a thickness of at least 0.5 mm, preferably 1 to 5 mm. According to another example, in the case of a tire for a large vehicle or an agricultural vehicle, the preferred thickness can be 1 to 6 mm. According to another example, in the case of a tire for a vehicle in the field of earthmoving machinery or an aircraft, the preferred thickness can be 2 to 10 mm. Finally, according to another example, in the case of a bicycle tire, the preferred thickness can be 0.4 to 2 mm.

[0080] The condensation-curing self-adhesive silicone-based product derived from the above two-component moisture-curing silicone tire sealant composition is a tacky solid (at 23 °C), and is particularly characterized by its very high flexibility and deformation properties due to its specific formulation. One advantage of the use of the composition described herein is that the cured layer has the advantage that it is substantially disadvantage-free compared to a tire having no self-sealing layer in terms of rolling resistance within a very wide range of the practical temperatures of the tire. Since silicone-based materials have greater resistance to extreme temperature changes than many organic alternatives, compared to non-silicone self-sealing compositions, during use at relatively high temperatures (typically above 60 °C), which are the temperatures frequently encountered during the use of some tires, the risk of excessive creep is significantly reduced. Its self-sealing properties are also improved during use at low temperatures (typically below 0 °C).

[0081] Furthermore, the condensation-curing self-adhesive silicone-based product derived from the aforementioned condensation-curing silicone-based composition has a storage modulus of 9,000 to 26,000 Pa. It has been confirmed that a storage modulus between the above two values gives an appropriate balance of flexibility (adhesiveness to nails or itself) and hardness (creep resistance / flow resistance under pressure). A condensation-curing silicone-based composition showing such a storage modulus at 23 °C will show a storage modulus that still satisfies the balance of modulus required to act as a self-sealing coating for tires at other temperatures, i.e., 25 to 100 °C.

[0082] When foreign objects such as nails pass through the structure of the tire, the condensation-curing self-adhesive silicone-based product functioning as a self-sealing layer is subjected to multiple stresses. In response to these stresses, due to its advantageous deformability and elastic properties, the composition generates a non-permeable contact area around the foreign object. Regardless of whether the contour or cross-sectional shape of the foreign object is uniform or regular, the self-sealing composition can enter openings of very small sizes due to its flexibility. This interaction between the self-sealing composition and the foreign object seals the area affected by the foreign object.

[0083] When a foreign object is removed, regardless of whether it is accidental or intentional, a puncture hole remains, which, depending on its size, is likely to cause a relatively large leak. The condensation-curing self-adhesive silicone-based product exposed to hydrostatic pressure is flexible and deformable enough to seal the puncture hole by being deformed, preventing the leakage of the inflation gas. Particularly in the case of tires, it has been found that the flexibility of the self-sealing composition enables it to withstand the forces of the surrounding walls without problem even in situations where a loaded tire deforms during running / rotation.

[0084] The above description has mainly focused on the use of the composition in tires, but it should be understood that the condensation-curing self-adhesive silicone-based product obtained from the above composition may be used as a puncture self-sealing layer for any type of "inflatable" article, that is, any article that takes a usable form when inflated with air by definition. Examples of such inflatable articles include, for example (but not limited to), inflatable boats and balloons or balls used in games or sports. As described, the two-component composition is applied to the inner wall of the inflatable article, completely or at least partially covering the inner wall.

[0085] The condensation-curing self-adhesive silicone-based product is well-suited for use as a puncture self-sealing layer in tires of industrial vehicles selected from passenger cars, SUVs (Sports Utility Vehicles), two-wheel vehicles (especially bicycles and motorcycles), airplanes, or light vans, "large" vehicles, that is, subways, buses, road transport vehicles (truck, tractor, trailer), off-road vehicles, such as agricultural or construction machinery, and other transport or handling vehicles. Examples Comparative Examples 1 and 2 obtained from WO 2018 / 024857.

[0086] Comparative Examples All viscosity measurements were made at 23 °C using a Brookfield cone plate viscometer RV DIII with the most appropriate cone plate, unless otherwise specified.

[0087] For the examples, the following commercially available tires were purchased and used for the comparative examples: · Bridgestone (registered trademark) Turanza ER300 205 / 55 / 16 91H, · Continental (registered trademark) Conti Premium Contact 5 205 / 55 / 16 91W, · Goodyear (registered trademark) Efficient Grip 205 / 55 / 16 91H, · Michelin (registered trademark) Energy Saver 205 / 55 / 16 91V, and · Pirelli (registered trademark) Cinturato P7 205 / 55 / 16 91V.

[0088] Preparation of Comparative Base A 73.01 g of Nanocyl (registered trademark) NC7000 carbon nanotubes, 3544.2 g of OH-terminated polydimethylsiloxane (showing a viscosity of about 50,000 mPa·s and a number average molecular weight (Mn) of 63,000 g / mol), and 382.8 g of trimethoxysilyl-terminated polydimethylsiloxane (showing a viscosity of about 56,000 mPa·s and a number average molecular weight (Mn) of 62,000 g / mol) were added to a Neulinger 5-liter mixer. These were first mixed at 50 rpm for 2 minutes using a planetary mixer, then at 50 rpm with the planetary mixer and 700 rpm with the disk for an additional 15 minutes, and finally at 100 rpm with the planetary mixer and 700 rpm with the disk for an additional 30 minutes. The resulting base product was then removed into a bucket.

[0089] Preparation of Base B 1500 g of Evonik® Printex A carbon black, 8825 g of OH-terminated polydimethylsiloxane (showing a viscosity of about 50,000 mPa·s and a number average molecular weight (Mn) of 63,000 g / mol), and 973 g of trimethoxysilyl-terminated polydimethylsiloxane (showing a viscosity of about 56,000 mPa·s and a number average molecular weight (Mn) of 62,000 g / mol) were added to a 20-liter bucket and mixed for 60 minutes with a Collomix Biax paddle mixer.

[0090] Preparation of the Mixture Comparative Example 1 24.87 g of trimethoxysilyl-terminated polydimethylsiloxane (showing a viscosity of about 56,000 mPa·s and a number average molecular weight (Mn) of 62,000 g / mol) and 0.133 g of tetra-n-butyl titanate were combined and mixed for 30 seconds at 2300 rpm with a dental mixer. 250 g of Base A was introduced into a plastic container. The above-mentioned preliminary mixture of trimethoxysilyl-terminated polydimethylsiloxane (viscosity 56,000 mPa·s) and tetra-n-butyl titanate was added to the container and mixed 4 times for 30 seconds at 2300 rpm with a speed mixer.

[0091] Comparative Example 2 28.85 g of trimethoxysilyl-terminated polydimethylsiloxane (showing a viscosity of about 56,000 mPa·s and a number average molecular weight (Mn) of 62,000 g / mol) and 0.155 g of tetra-n-butyl titanate were combined and mixed for 30 seconds at 2300 rpm with a dental mixer. 290 g of Base 2 was introduced into a plastic container. The above-mentioned preliminary mixture of trimethoxysilyl-terminated polydimethylsiloxane (viscosity 56,000 mPa·s) and tetra-n-butyl titanate was added to the container and mixed 4 times for 30 seconds at 2300 rpm with a speed mixer.

[0092] A detailed table of the compositions of Comparative Examples 1 and 2 tested is shown in Table 1. The test results regarding the tires during the following running are shown in Tables 2a - c.

Table 1

[0093] Evaluation of hardness and storage elastic modulus The hardness of the cured elastomer was observed using a TA XT plus texture analyzer. The probe used was a polycarbonate cylinder terminated with a spherical end. The diameter of the probe and the sphere was 1 / 2 inch (1.27 cm). A return to start program was used. The pre-test speed was 5 mm / s and the trigger force was 0.1 g. The test speed was 1 mm / s. The probe was inserted 5 mm into the product and then moved to a distance where no significant force was measured. The maximum positive and negative forces were measured and reported herein. A higher positive force represents a higher hardness elastomer. A higher negative force represents a more adhesive elastomer.

[0094] Evaluation of sealing efficiency Using a press and a cutting cylinder, a 3 mm diameter hole was cut out on the rotating band of the tire. The products obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were each filled into a 310 mL cartridge, applied inside the tire, and smoothed to the designed thickness using a ruler.

[0095] The products of Examples 1 and 2 and Comparative Examples 1 and 2 were applied to the desired thickness to cover without filling the three holes in the tire. After curing for 7 days at 23 °C and a relative humidity of 50%, the tire was mounted on a wheel and pressurized at 1 bar (0.1 MPa). A 5 mm diameter nail was pushed into the 3 mm hole until the distance inside the tire reached 40 mm. Then the pressure was increased to 2.7 bar (0.27 MPa) and the hole was removed from the tire.

[0096] For the next few hours and days, a string repair plug without cementitious material was filled into the leaking holes, and optionally water was used to track the leak until no leak was observed. The tire was held for two weeks after repair. After 14 days, the results are reported in Table 2 if there is no loss exceeding 0.1 bar (0.01 MPa). 3 / 3 means that no leak was observed in any of the three holes. 0 / 3 means that all three holes leaked and thus needed repair. [Table 2]

[0097] Comparative Examples 1 and 2 show excellent airtightness results, indicating that an appropriate crosslink density is required to obtain a product that seals the tire. [Table 3] [Table 4]

[0098] The results of the texture analyzer for the examples show that a compromise between hardness and tack is required to obtain appropriate performance in the tire. Comparative Examples 1 and 2 show an appropriate balance of hardness and tack to close the gaps caused by nails without showing creep, but they have low absolute tack and thus can be troubled by some foreign objects and tack problems due to self-sealing punctures. However, each of the compositions used above was found to have an absolute tack of <0.5, which is significantly less than that used herein.

[0099] Example 8 and Comparative Examples 3 and 4 Preparation of the base As shown in Table 3 below, the base compositions for five evaluated compositions were prepared using 260.87 g of OH-terminated polydimethylsiloxane showing viscosity at room temperature and mixing with 39.13 g of Printex A type carbon black using a speed mixer four times for 30 seconds at a speed of 2300 rpm. During each mixing, a spatula was used to homogenize the mixture.

Table 5

[0100] Preparation of curing agent 313.04 g of trimethoxysilyl-terminated polydimethylsiloxane having a viscosity of about 56,000 mPa at 23 °C (Brookfield cone plate viscometer RV DIII using cone plate CP-52 at 3 rpm) was mixed with 1.25 g of tetra n-butoxytitanium using a speed mixer four times for 30 seconds at a speed of 2300 rpm.

[0101] Preparation of mixture 300 g of the base prepared as above was mixed with 26.09 g of the curing agent four times for 30 seconds at a speed of 2300 rpm. During each mixing, a spatula was used to homogenize the mixture. Then, the mixed compound was mixed four times for 30 seconds at a speed of 2300 rpm. During each mixing, a spatula was used to homogenize the mixture. The mixture was introduced into a 310 ml cartridge and over-distributed into an aluminum cup with a diameter of 50 mm and a height of 15 mm. The product was shaped with a metal plate to produce a flat surface and then cured at room temperature for 28 days.

[0102] Results The hardness of the cured elastomer was observed using a Stable Micro Systems TA XT plus texture analyzer. The probe used was a polycarbonate cylinder terminated with a spherical end. The Stable Micro Systems TA XT+ with a 1 / 2 inch (1.27 cm) hemispherical probe made of polycarbonate was set to penetrate 5 mm of the sample in the product at a speed of 0.1 mm / s and then removed to a distance where no significant force was measured. The maximum positive [F+] and negative [F-] forces were measured and reported herein. A higher positive force represents a harder elastomer. A higher negative force represents a more adhesive elastomer. However, since the probe needs to penetrate 5 mm into the product, harder materials also induce a stronger pressure on the probe and generally increase the measured negative force. To determine the absolute adhesiveness, the ratio of both values was calculated as follows. Absolute adhesiveness = -[F-] / [F+]

Table 6

[0103] A ratio greater than 1 is characteristic of materials that exhibit an adhesive strength [F-] higher than the hardness strength [F+]. Mixtures B, C, and D exhibit a ratio greater than 1, which means that the absolute adhesiveness is higher than that of mixtures A and B. To maximize the absolute adhesiveness, it is preferred to use a polymer showing a viscosity in the range of 13,500 to 330,000 mPa·s and more preferably in the range of 50,000 to 150,000 mPa·s.

[0104] Ratios greater than 1:1 or greater than 1.025:1 are characteristic of materials that exhibit an adhesive strength [F-] that is higher than the hardness strength [F+]. Mixtures B, C, and D exhibit an absolute adhesion value greater than 1.025, which means that their absolute adhesiveness is higher than that of mixtures A and E. Therefore, in order to maximize the absolute adhesiveness, it is preferable to use a polymer that exhibits a viscosity included in the range of 13,500 to 330,000 mPa·s, and more preferably 50,000 to 150,000 mPa·s.

Claims

1. A condensation-curing silicone-based composition comprising: (i) an organopolysiloxane polymer having two or more silicon-bonded hydroxyl groups or hydrolyzable groups per molecule and having a viscosity of 50,000 mPa·s to 150,000 mPa·s at 23°C; (ii) a crosslinking agent comprising a silyl-functional polymer having at least two silyl groups, each silyl group containing at least two hydrolyzable groups; (iii) a condensation catalyst selected from the group consisting of titanates and / or zirconates, and optionally (iv) a reinforcing filler or a non-reinforcing filler, wherein the molar ratio of all silicon-bonded hydroxyl groups to all hydrolyzable groups is > 2:1, and when the composition cures, it provides a self-adhesive silicone-based product having an absolute adhesiveness of ≧ 1.025, where absolute adhesiveness = -[adhesion strength (F-)] / [hardness strength (F+)], a condensation-curing silicone-based composition.

2. The condensation-curing silicone-based composition according to claim 1, wherein the composition comprises one or more reinforcing fillers or non-reinforcing fillers (iv) selected from fumed silica, precipitated silica, calcium carbonate, carbon black, hollow glass beads, and / or carbon nanotubes.

3. The condensation-curing silicone-based composition according to claim 1 or 2, wherein the filler is multi-walled carbon nanotubes and / or carbon black.

4. The condensation-curing silicone-based composition according to any one of claims 1 to 3, wherein the composition is in two parts and is stored as a base part containing the polymer (i) and, if present, the filler (iv), and a curing part containing the crosslinking agent (ii) and the catalyst (iii).

5. The polymer (i) further comprises a polydiorganosiloxane having one silanol-containing terminal group and one non-reactive terminal group, and / or the crosslinking agent (ii) further comprises a silyl-functional molecule having at least two silyl groups, at least one silyl group containing one hydrolyzable group, the condensation-curing silicone-based composition according to any one of claims 1 to 4.

6. A condensation-curing self-adhesive silicone-based product obtained from the condensation-curing silicone-based composition according to any one of claims 1 to 5.

7. The condensation-curing self-adhesive silicone-based product according to claim 6, wherein the product is a pressure-sensitive adhesive, a self-adhesive material, and / or a self-sealing material.

8. The condensation-curing self-adhesive silicone-based product according to claim 6 or 7, as a puncture self-sealing layer in an inflatable article.

9. The condensation-curing self-adhesive silicone-based product according to claim 8, characterized in that the inflatable article is a self-sealing pneumatic tire.

10. The self-sealing pneumatic tire is a) a tire body having an outer tread surface and an inner surface; and b) a puncture self-sealing layer of the condensation-curing self-adhesive silicone-based product adhered to the inner surface, the condensation-curing self-adhesive silicone-based product according to claim 9.

11. The condensation-curing self-adhesive silicone-based product according to claim 10, wherein the puncture self-sealing layer has a thickness of 0.5 mm to 10 mm.

12. Use of the condensation-curing self-adhesive silicone-based product according to claim 6 as a puncture self-sealing layer in a pneumatic tire of an inflatable article.

13. Use of the condensation-curing self-adhesive silicone-based product according to claim 12, wherein the inflatable article is a self-sealing pneumatic tire.

14. An inflatable article, comprising an outer surface and an inner surface, having a self-sealing silicone layer applied to the inner surface thereof, wherein the self-sealing silicone layer is cured from the condensation-curing silicone-based composition according to any one of claims 1 to 5, the inflatable article.

15. The inflatable article according to claim 14, wherein the inflatable article is a pneumatic tire containing the condensation-curing self-adhesive silicone-based product according to any one of claims 6 to 11.

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