Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/24—Acids; Salts thereof
  • C08K3/26—Carbonates; Bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2190/00—Compositions for sealing or packing joints

Definitions

• the present invention relates to filled adhesives, especially filled silane-crosslinking adhesives.
• Polyurethane polymers have long been known as especially suitable materials for adhesive applications requiring high flexibility in conjunction with good strengths.
• One-component systems in which isocyanate end groups of the polyurethane polymer react with atmospheric moisture to crosslink the polymer, have the advantage of simple applicability, since they require no metering of the second component and no mixing operation. Systems of this kind find widespread application as adhesives and sealants in industry and in construction.
• a further development of these polyurethane polymers involves replacing the isocyanate functional groups by silane groups, which likewise crosslink with atmospheric moisture to form Si—O—Si bonds.
• silane-crosslinking polyurethane polymers by reaction of the terminal isocyanate groups with mercapto-functional or amino-functional silanes is described for example in U.S. Pat. No. 3,632,557 (Union Carbide) and U.S. Pat. No. 5,364,955 (Bayer).
• U.S. Pat. No. 3,632,557 (Union Carbide) describes the preparation of silane-crosslinking organic polymers by reacting terminal isocyanate groups of polyurethane prepolymers with mercapto-functional or amino-functional silanes. These polymers may comprise, inter alia, a filler. Neither calcium carbonate nor soot are listed as examples.
• U.S. Pat. No. 5,364,955 (Bayer) describes, for the preparation of silane-crosslinking polyurethane polymers, special secondary aminosilanes (aspartic ester derivatives) which are attached to polyurethane prepolymers having isocyanate end groups.
• the silane-terminal polymers can be used for formulating sealing materials. Indications of especially suitable fillers for achieving special properties are not mentioned.
• crosslinking via silane groups is that, on the one hand, crosslinking is not accompanied by the formation of any CO 2 , which under certain circumstances can lead to disruptive bubbles in the adhesive, and that, on the other hand, the user does not come into contact with monomeric isocyanates, which are a potential health hazard.
• U.S. Pat. No. 6,001,946 (Witco) describes more or less the same silane-terminal polyurethane prepolymers, based on aspartic ester derivatives of amino-functional silanes, as U.S. Pat. No. 5,364,955.
• Reinforcing fillers listed include fumed silica, precipitated silica, and calcium carbonate, with treated calcium carbonate having a particle size of from 0.07 to 4 microns particle size being referred to as a preferred filler. These fillers can be used alone or as a filler combination. As a preferred quantity of filler mention is made of from 80 to 150 parts per 100 parts of polymer. On the basis of that patent it is possible to achieve adhesives having tensile strengths of approximately 1.5 MPa with approximately 300% elongation. Adhesives of this kind are not strong enough for use in the automobile industry.
• EP 0 676 403 (Witco) describes silane-terminal polyurethane polymers containing arylamino-functional silanes. Sealants based on these polymers are said to have higher elongation, higher flexibility, and a lower elasticity modulus than the prior art at that time. Described as preferred calcium carbonate fillers are treated types having particle sizes of from 0.05 to 10 microns in an amount of up to 100 parts per 100 parts of polymer. On the basis of that patent it is possible to achieve adhesives having tensile strengths of approximately 2.8 MPa at 300% elongation. This tensile strength is still too low for application in the automobile industry. Additionally it has been found that silane-crosslinking polyurethane polymers which comprise phenyl-amino silane have a poor aging stability in the cured state under hot storage.
• U.S. Pat. No. 5,703,146 (Kaneka) describes sealants composed of 100 parts of silane-terminal oxypropylene polymer with a narrow molecular weight distribution, from 100 to 200 parts of calcium carbonate with a particle size of not more than 0.5 micron, and surface-treated with a fatty acid, and a number of further additions.
• the polymer has a fraction of 15-35% in the overall composition.
• U.S. Pat. No. 4,222,925 (Inmont Corporation) describes an adhesive with a rapid curing rate and high strength, which is used in combination with a primer in automobile engineering to glue in windshields.
• the adhesive is composed of a silane-terminal polyurethane polymer (prepared as described in U.S. Pat. No. 3,632,557), a special amino-functional silane, and soot with a water content of not more than 0.05%.
• the addition of dried soot is said significantly to increase the mechanical strength of the adhesive.
• General indications of the amount of soot used are absent, though example 2 discloses the use of 35 parts of soot per 100 parts of polymer, which leads to very high mechanical values.
• An adhesive formulation with a total fraction of 73% polymer in the formulation is too expensive, however, for a utility in tune with practice.
• WO 99/55755 (Essex) describes a method of gluing windows into a structure.
• the adhesive used is based on a silane-terminal oxyalkylene polymer, a silane-terminal polyurethane polymer, or similar silane-terminal systems.
• the polymer preferably has a fraction in the overall composition of the adhesive of from 45 to 85%, contains a tin catalyst in a preferred amount of from 0.1 to 0.4%, a special amino-functional silane and other additives.
• Soot, calcium carbonate, and other reinforcing fillers are listed as possible additives, with preference being given to soot as the sole reinforcing filler used.
• An amount of reinforcing filler of from 20 to 33%, based on the overall adhesive composition, is preferred, and compositions having tensile strengths of up to 1028 psi ( 7.1 MPa) are disclosed.
• EP 0 819 749 (Simson) describes silane-crosslinking adhesives and sealants with high electrical resistance which are suitable for industrial applications, such as the gluing in of auto windshields, or, in particular, as an adhesive and sealant for electrical appliances.
• These adhesives and sealants must include the following components: silane-terminal polymer, crosslinking catalyst, dryer, adhesion promoter, and rheology controller, it being possible for from 25% to 55% of the composition to be in the form of a calcium carbonate filler.
• EP 0 931 800 (Witco Corp.) describes sealants having improved mechanical values, good curing rate, low surface tack and not excessively high viscosity. They are based on a silane-terminal polyurethane prepolymer which is prepared by reacting an OH-terminal polyurethane prepolymer with an isocyanate-functional silane. Possible reinforcing fillers mentioned include fumed silica, precipitated silica, and calcium carbonate, with soot being proposed as the principal filler in order to bring about even further reinforcement. Treated calcium carbonates having particle sizes of from 0.07 to 4 microns are preferred fillers. The fillers can be used alone or in combination, with the stated preferred amount of filler being from 80 to 150 parts per 100 parts of polymer. The maximum tensile strength achieved in the examples is 2.7 MPa.
• a high electrical volume resistance is also important because an excessive conductivity of the adhesive layer can cause disruptions to the receiving of radio when rear screens with built-in aerials are glued in.
• a further prerequisite for an adhesive in tune with practice is its good applicability.
• the uncured adhesive must be able to be extruded from the cartridge with reasonable force in the case of repair.
• the extrusion force from the cartridge through an opening with a diameter of 5 mm ought not to exceed a level of 2 000 N.
• silane-crosslinking polyurethane adhesives that meet the aforementioned requirements for the adhesive bonding of components in the automobile industry can be formulated by combining a special, silane-crosslinking polyurethane polymer in a defined range with fine-particle coated calcium carbonate and soot.
• the present invention accordingly provides adhesives able to meet the requirements specified above.
• Such adhesives of the invention comprise the following three constituents:
• R 1 stands for an alkyl group having 2 to 8 carbon atoms, linear or branched
• R 2 stands for an alkyl radical having 1 to 8 carbon atoms
• R 3 stands for an alkyl radical having 1 to 5 carbon atoms
• a stands for 0 or 1
• Z stands for a sulfur or an NR 4 , where R 4 stands for a hydrogen atom or an organic radical, for example, an alkyl group or an aryl group having 1 to 20 carbon atoms, or a compound having ester groups such as, for example, a moiety of the formula (II)
• R 5 stands for an alkyl group having 1 to 8 carbon atoms
• n denotes a number from 2 to 4,
• A stands for a radical of a polyurethane prepolymer with the functionality n
• fin e-particle coated calcium carbonate by which is meant fatty acid-treated calcium carbonates having a particle size of from 0.05 to 1 micron, with a density of approximately 2.6-2.7 g/ml, and
• A stands for a polyurethane radical obtainable by reacting commercially customary polyols with an excess of commercially customary polyisocyanates, the average molecular weight of A usually being in the range from 500 to 100 000 g/mol, and A containing at least n urethane groups.
• A denotes a radical of the formula (III)
• Q stands for an aromatic, aliphatic or cycloaliphatic radical which represents in particular a polyisocyanate, with special preference a commercially customary diisocyanate, following elimination of two or more isocyanate groups, and
• P stands for a radical which represents a polyoxyalkylene-polyol or polyalkyldiene-polyol, in particular a commercially customary polyol, following elimination of at least two OH groups,
• X denotes a radical of the formula (IV)
• the resultant adhesives are suitable for the sealing adhesive bonding of components which consist at least in part of metal, as in the automobile industry, for example.
• the adhesives have good mechanical properties, a high electrical volume resistance, good applicability and reasonable raw materials costs. They can be applied effectively (i.e., they have an extrusion force of not more than 2 000 N), they have a tensile strength of at least 4.5 MPa, an elongation break of at least 250%, and they have an electrical volume resistance of at least 10 8 ohm cm.
• silane-crosslinking polyurethane polymer which is constructed in accordance with the following formula (I):
• R 1 stands for an alkyl group having 2 to 8 carbon atoms, linear or branched
• R 2 stands for an alkyl radical having 1 to 8 carbon atoms
• R 3 stands for an alkyl radical having 1 to 5 carbon atoms
• a stands for 0 or 1
• Z stands for a sulfur or an NR 4 , where R 4 stands for a hydrogen atom or an organic radical, for example, an alkyl group or an aryl group having 1 to 20 carbon atoms, or a compound having ester groups such as, for example, a moiety of the formula (II)
• R 5 stands for an alkyl group having 1 to 8 carbon atoms
• n denotes a number from 2 to 4,
• A stands for a radical of a polyurethane prepolymer with the functionality n.
• A stands for a polyurethane radical obtainable by reacting commercially customary polyols with an excess of commercially customary polyisocyanates, the average molecular weight of A usually being in the range from 500 to 100 000 g/mol, and A containing at least n urethane groups.
• A denotes a radical of the formula (III)
• Q stands for an aromatic, aliphatic or cycloaliphatic radical which represents in particular a polyisocyanate, with special preference a commercially customary diisocyanate, following elimination of two or more isocyanate groups, and
• P stands for a radical which represents a polyoxyalkylene-polyol or polyalkyldiene-polyol, in particular a commercially customary polyol, following elimination of at least two OH groups,
• X denotes a radical of the formula (IV)
• P 1 P or denotes P(X) u , with the proviso that not more than one P 1 is P(X) u and where
• Q stands for a radical which represents a diisocyanate, in particular a commercially customary diisocyanate, following elimination of the two isocyanate groups
• Preferred polyisocyanates are diisocyanates. Examples that may be mentioned include the following isocyanates, which are very well known in polyurethane chemistry:
• Polyols which, following elimination of at least two OH groups, produce the radical P are preferably the following raw materials, which are very well known in polyurethane chemistry, or mixtures thereof:
• polyetherpolyols which are the polymerization product of ethylene oxide, propylene oxide or butylene oxide or mixtures thereof, or hydroxy-terminated polybutadiene polymers.
• the polyols generally have an OH functionality of from 1.8 to 3 and a molecular weight from 500 to 20 000 g/mol.
• silane-terminated prepolymers used in accordance with the invention can be prepared by reacting, in a first step, polyols with an excess of polyisocyanate, to give a prepolymer having isocyanate end groups. These isocyanate end groups are subsequently reacted with an organofunctional silane containing an isocyanate-reactive group.
• Suitable organofunctional silanes are compounds with the formula (VI)
• R 1 , R 2 , R 3 and a have the definition described above and Y stands for —SH or —NH 2 or —NHR 4 , and R 4 likewise has the definition described above.
• Particularly suitable is an amino silane containing as R 4 the following moiety (II)
• R 5 stands for an alkyl group having 1 to 8 carbon atoms.
• An example that may be mentioned of an organofunctional silane compound of this kind is the one below, prepared from diethyl maleic and ⁇ -aminopropyltrimethoxysilane:
• Suitable polyisocyanates for preparing such a prepolymer include the aliphatic, cycloaliphatic or aromatic isocyanates having at least two isocyanate groups per molecule, likewise mentioned already above as “suppliers” of the radical Q.
• the preparation can take place by reacting the polyol component and the isocyanate component by customary methods, e.g., at temperatures of from 50 to 100° C., where appropriate using suitable catalysts, and employing the isocyanate component in excess.
• the reaction product formed is the aforementioned polyurethane prepolymer having isocyanate end groups.
• This prepolymer is subsequently reacted with the isocyanate-reactive organofunctional silane described, and the aforementioned silane-terminal polyurethane prepolymer is formed.
• the organofunctional silane is used stochiometrically or in a slight excess in relation to the isocyanate groups.
• Particularly suitable as the fine-particle coated calcium carbonate described under b) are calcium carbonates which have been surface-coated with fatty acids, such as stearates, for example, and which have an average particle size of from 0.05 to 1 micron.
• the amount of organic substance ranges between 0.9 and 5% weight fractions.
• grades which are especially suitable are Winnofil SP and Winnofil SPT from ICI or Socal U1S2 from Solvay.
• the density of these materials is from about 2.6 to 2.7 g/ml.
• the soot specified under c) is preferably a grade having a large surface area and having a density of approximately 1.8 g/ml,
• soot grades are suitable, provided they have been dried before being mixed into the prepolymer. In order to reduce the electrical conductivity it is possible to use fully or partly oxidized soot grades, these grades being more expensive and therefore being usable only in restricted form—in order to give a market-compatible product which is not too expensive.
• the adhesive of the invention may comprise one or more of the following constituents:
• Plasticizers examples being organic esters, e.g., phthalates such as dioctyl phthalate or diisodecyl phthalate, adipates such as dioctyl adipate, for example, polybutenes or other compounds which are not reactive toward silanes, solvents, further organic or inorganic fillers such as, for example, other calcium carbonates, kaolines, aluminas, silicas, fibers, e.g., of polyethylene, pigments, thickeners, e.g., urea compounds or poly-amide waxes, heat stabilizers or UV stabilizers, adhesive promoters, e.g., amino silanes or epoxy silanes, especially H 2 N—(CH 2 ) 3 —Si(OCH 3 ) 3 , H 2 N—(CH 2 ) 2 —NH—(CH 2 ) 3 —Si(OCH 3 ) 3 or NH—[(CH 2 ) 3
• organic esters
• the adhesives of the present invention have the advantage that they are isocyanate-free and, by virtue of the inventive combination of a special silane-crosslinking polyurethane prepolymer, soot, and fine-particle coated calcium carbonate, are suitable for applications requiring at one and the same time tensile strengths of more than 4.5 MPa, elongations at break of more than 250%, an electrical volume resistance of more than 10 8 ohm cm, and good applicability. Examples of such applications are the sealing and adhesive bonding of metallic components, especially flexible adhesive bonding.
• the adhesives of the invention are therefore, on the one hand, suitable for the production of buses, trucks, and rail vehicles, and, on the other hand, are even able to meet the requirements imposed on assembly adhesives in the automobile industry.
• the extrusion force was determined in aluminum cartridges having a diameter of 45 mm, the adhesive being pressed through an opening of 5 mm at the tip of the cartridge. Extrusion took place by means of a tensile testing machine, with recording of the required force, at a rate of 60 mm/min.
• the ingredients of the individual examples were mixed homogeneously in the order according to table 1 in a suitable vacuum mixer, e.g., Planimax from Molteni.
• a suitable vacuum mixer e.g., Planimax from Molteni.
• the prepolymer, the plasticizer, and the fillers were homogenized, and subsequently the additional silanes and the catalyst solution were mixed in.
• the finished adhesives were filled into airtight cartridges.
• inventive adhesives of examples 3 to 7 meet the required properties, i.e., they have a tensile strength of at least 4.5 MPa, an elongation at break of at least 250%, an electrical volume resistance of at least 10 8 ohm cm, an extrusion force of not more than 2 000 N.

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• Chemical & Material Sciences (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 2001
  • 2001-05-10 EP EP01111158A patent/EP1256595A1/de not_active Withdrawn
• 2002
  • 2002-04-18 JP JP2002587485A patent/JP4546030B2/ja not_active Expired - Fee Related
  • 2002-04-18 MX MXPA03010167A patent/MXPA03010167A/es not_active Application Discontinuation
  • 2002-04-18 WO PCT/IB2002/001247 patent/WO2002090411A1/de active Application Filing
  • 2002-04-18 DE DE50214315T patent/DE50214315D1/de not_active Expired - Lifetime
  • 2002-04-18 CA CA002446677A patent/CA2446677A1/en not_active Abandoned
  • 2002-04-18 US US10/476,525 patent/US20040127622A1/en not_active Abandoned
  • 2002-04-18 BR BRPI0209486-0A patent/BR0209486B1/pt not_active IP Right Cessation
  • 2002-04-18 EP EP02720361A patent/EP1397406B1/de not_active Revoked
  • 2002-04-18 AT AT02720361T patent/ATE462742T1/de not_active IP Right Cessation
• 2003
  • 2003-09-25 ZA ZA200307430A patent/ZA200307430B/en unknown
• 2006
  • 2006-04-07 US US11/399,364 patent/US20060183846A1/en not_active Abandoned
• 2007
  • 2007-11-30 US US11/948,836 patent/US7589134B2/en not_active Expired - Fee Related
• 2009
  • 2009-11-02 JP JP2009252374A patent/JP2010024461A/ja not_active Withdrawn

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