Low temperature curing compositions for rubber-based adhesives and sealants

Abstract

The present invention relates to a rubber-based composition which can be thermally cured at reduced temperatures while maintaining properties over a wide curing temperature window, the composition comprising at least one solid rubber, at least one diene-based polymer or copolymer comprising an olefinic double bond and / or an aromatic substituted olefin, they are suitable for curing with curing systems present as quinone dioximes, peroxides and optionally polyfunctional acrylates, preferably in the absence of elemental sulfur. The cured compositions exhibit improved reversion resistance and adhesive strength on aluminum.

Description

Technical Field

[0001] The present invention relates to heat-curable rubber-based compositions useful in adhesives and / or sealants; to cured products thereof; and to methods of making and using the same. Background Art

[0002] With the advent of low-temperature cure for electrocoat (e-coat) coatings, there is a need for adhesives and sealants that co-cure with these coatings to achieve performance under the same conditions. Typical cure temperatures for automotive adhesives and sealants range from 160°C to 200°C, and newer e-coat coatings are targeting lower cure temperatures, as low as 140°C.

[0003] Attempts have been made to produce adhesives and sealants that have a reduced cure temperature for curing with coatings in various manufacturing applications, but only partial success has been achieved. It has been proposed that rubber-based compositions can be cured at temperatures as low as 120°C by extending the cure time to 150 minutes (2.5 hours). However, such extended cure times are not usable in most production line assembly processes (including electrocoating, which passes the coated parts through an oven in about 10 to 20 minutes). Therefore, there is a need for low-temperature curing rubber-based adhesive and sealant compositions that can be cured at about 140°C or below and at cure times in the range of 5 minutes to about 25 minutes.

[0004] Accelerated cure systems can achieve cure below 160°C but exhibit poor storage stability, which limits shelf life. They are also sensitive to overbake (e.g., during a production line stop), which results in significant degradation at higher temperatures, greater than 200°C. One-component systems rely on packaging methods to maintain shelf life, which introduces cost and complexity to manufacturing.

[0005] Other previous low temperature compositions are two component systems which are inconvenient and introduce the risk of premature curing of the adhesive, poor wetting or open bead surface contamination if stored.Therefore, there is a need for low temperature curing rubber-based adhesive and sealant compositions with good storage stability.

[0006] Heat-curable rubber-based compositions are typically heated in an oven or the like at a temperature in the range of about 160 to 180°C for curing. However, in some cases, the temperature in the oven is raised to a higher temperature (e.g., 190°C or higher), and the heat-curable composition is exposed to a so-called overbaked state. Therefore, an object of the present invention is to provide a heat-curable composition having excellent adhesion to metal substrates, particularly aluminum, which exhibits substantially uniform curing characteristics at an oven temperature of 130°C to 200°C and exhibits a small amount of strength loss (referred to herein as reversion resistance) even when heated at a temperature of 190°C or higher.

[0007] In vehicle construction, one application of thermosetting rubber-based adhesive and sealant compositions is the so-called underlay applied between the body in white and the corresponding structural material present, for example, in roof arches, rocker panels, safety elements or reinforcement elements. The underlay can reinforce the vehicle structure and provide bonding, acoustic and / or sealing functions.

[0008] The growth of the electric vehicle (EV) market has brought new challenges to the traditional curing windows of adhesives and sealants. In particular, large reinforcements have been added to the rocker panels of many electric vehicles to protect the battery system. This additional mass requires more thermal energy to raise the temperature of the mass, thereby forming a heat sink, which results in the body in white not being able to reach a uniform curing temperature for adhesive and sealant curing during the electrocoat curing process. This uneven body temperature can lead to under-baking of large masses and / or over-baking of thinner structures (such as the roof). Therefore, there is a need for a low-temperature curing rubber-based composition that maintains strength despite curing at temperatures of about 190 to 230°C.

[0009] It is an object of the present invention to address one or more of the above-described disadvantages. Summary of the Invention

[0010] The present invention relates to heat-curable rubber-based compositions that can be cured at reduced temperatures of about 130°C to 140°C; cured compositions that are adhered to metal surfaces; adhesives, sealants, or sound attenuation products thereof that exhibit one or more of: improved reversion resistance (e.g., reduced strength loss after high temperature heating); excellent adhesion to aluminum; and products, components, or assemblies made with or comprising the compositions; and methods of making and using the foregoing.

[0011] The present invention cures at significantly lower temperatures of about 130° C. to 140° C. within a cure time of about 10 to 20 minutes, while exhibiting significant reversion resistance at high cure temperatures of about 190° C. to 230° C. This feature enables the composition to be used in white areas of the vehicle body where high temperatures are reached during cure (e.g., the roof) and low temperatures are reached (e.g., large bulk areas such as reinforced body parts).

[0012] The heat-curable composition comprises a low-temperature curing system that is preferably free of or substantially free of sulfur and comprises two or more of the following: a quinone dioxime; a peroxide; a multifunctional coagent, such as a (meth)acrylate monomer, oligomer, or polyol. While conventional accelerators other than the peroxides and unsaturated coagents disclosed herein, such as organic accelerators and / or one or more metal oxides, may be included, their amounts are preferably minimized and, in some embodiments, are absent. For example, dithiocarbamates (in the form of their ammonium or metal salts), xanthates, thiuram compounds (monosulfides and disulfides), thiazole compounds, aldehyde / amine accelerators (e.g., hexamethylenetetramine), dibenzothiazolyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), its zinc salt (ZMBT), zinc dibenzyldithiocarbamate (ZBEC), N-cyclohexylbenzodithiazolylsulfenamide (CBS).

[0013] In one aspect of the present invention, the composition may comprise natural and synthetic rubbers containing olefinic unsaturation, said rubbers being suitable for curing with a system comprising at least two of the following: a quinone dioxime, a peroxide, a polyfunctional coagent containing multiple α,β-unsaturated carbonyl functional groups.

[0014] The composition may additionally contain processing oils / plasticizers and fillers to promote pumpability and / or sag resistance in the uncured composition, as well as antioxidants, colorants or dyes, adhesion promoters, hydrocarbon resins other than the diene-based component, and rheology modifiers.

[0015] Various aspects of the present invention can be summarized as follows:

[0016] Aspect 1: A heat-curable composition comprising:

[0017] Component (a), said component (a) comprising:

[0018] (a1) solid rubber;

[0019] (a2) a polymer containing olefinic double bonds which is liquid or pasty at 22°C;

[0020] (a3) process oils; and

[0021] (a4) liquid polydiene;

[0022] and

[0023] Component (b) comprises a curing system of two or more of the following:

[0024] (b1) quinone dioxime;

[0025] (b2) Organic peroxides and

[0026] (b3) A multifunctional co-active agent containing multiple α,β-unsaturated carbonyl functional groups.

[0027] Aspect 2: The heat-curable composition according to aspect 1, further comprising component (c), wherein component (c) comprises:

[0028] (c1) a physical blowing agent in an amount of 0 to 3 wt % based on the total weight of the composition;

[0029] (c2) a chemical blowing agent in an amount of 0 to 4.0 wt %, based on the total weight of the composition; and

[0030] (c3) a urea-based blowing agent accelerator in an amount of 0 to 1 wt %.

[0031] Aspect 3. The heat-curable composition according to any one of the preceding aspects, wherein the curing system (b) is:

[0032] (b2) an organic peroxide present in an amount of 0.2 to 2.0 weight percent based on the total weight of the composition; and

[0033] (b3) a multifunctional coagent present in an amount of 0.3 to 7 weight percent based on the total weight of the composition.

[0034] Aspect 4. The heat-curable composition according to any one of the preceding aspects, wherein the amount of (c1), (c2) and (c3) is 0 wt % based on the total weight of the composition.

[0035] Aspect 5. The heat-curable composition according to any one of the preceding aspects, wherein the polymer containing ethylenic double bonds (a2) comprises polybutadiene grafted with about maleic anhydride and has a mass average molecular weight of 10,000 to 750 Daltons.

[0036] Aspect 6. The heat-curable composition according to any one of the preceding aspects, wherein the polybutadiene grafted with maleic anhydride (a2) comprises 4 to 20 pbw of maleic anhydride moieties.

[0037] Aspect 7. The heat-curable composition according to any one of the preceding aspects, wherein the (a3) ​​processing oil comprises paraffin oil in an amount of 5 wt% to 30 wt% based on the total mass of the composition.

[0038] Aspect 8. The heat-curable composition according to any one of the preceding aspects, wherein the (a4) liquid polydiene different from (a1 to a3) is a polybutadiene polymer having a mass average molecular weight of 1,000 to 50,000 g / mol.

[0039] Aspect 9. The thermally curable composition according to any one of the preceding aspects, wherein the (b3) multifunctional coagent comprising a monomer, oligomer, or polymer having multiple α,β-unsaturated carbonyl functional groups comprises at least one trifunctional (meth)acrylate.

[0040] Aspect 10. The heat-curable composition according to any one of the preceding aspects, wherein:

[0041] The (a1) solid rubber is present in an amount of about 8 to 20 weight % based on the total weight of the composition;

[0042] The (a2) polymer containing olefinic double bonds that is liquid or pasty at 22° C. is present in an amount of about 5 to 15% by weight based on the total weight of the composition;

[0043] the (a3) ​​processing oil is present in an amount of about 5 to 30 weight percent based on the total weight of the composition;

[0044] The (a4) liquid polydiene different from (a1) to (a3) ​​is present in an amount of about 3 to 20 weight percent based on the total weight of the composition;

[0045] the (b1) quinone dioxime is present in an amount of 0.1 to 5 wt % based on the total weight of the composition;

[0046] (b2) the organic curing agent is an organic peroxide, which is present in an amount of 0.05 to 5.0 weight percent based on the total weight of the composition; and

[0047] The (b3) multifunctional coagent is present in an amount of 0.1 to 10 wt % based on the total weight of the composition; and

[0048] The heat-curable composition further comprises the following substances as additional components:

[0049] calcium oxide present in an amount of 0.1 to 6% by weight; and

[0050] fillers present in a total amount of 10 to 50% by weight;

[0051] All weight % amounts are based on the total mass of the composition; and

[0052] The components are selected such that the heat curable composition has a viscosity such that the composition can be pumped at a temperature in the range of 15 to 60°C.

[0053] Aspect 11. The heat-curable composition according to any one of the preceding aspects, further comprising a filler (d) in an amount of 10 wt% to 45 wt% based on the total weight of the composition.

[0054] Aspect 12. An article comprising a component having a metal surface, wherein the metal surface is preferably an aluminum surface, and adhered to the metal surface is a composition according to any one of the preceding aspects, the composition being cured at a temperature in the range of 120 to 140° C. for a time in the range of 10 to 20 minutes to form an adhesive bond between two parts of the article and / or seal the surface of the article, wherein the article is a component of a vehicle, equipment, tool or aircraft.

[0055] Aspect 13. A method for applying an adhesive or sealant to a metal substrate having at least one aluminum metal surface, comprising the steps of:

[0056] delivering the composition according to any one of the preceding aspects to the point of application at a temperature in the range of 15 to 60°C, preferably by means of a pump;

[0057] depositing the composition in a liquid or paste state onto selected areas of the first aluminum metal surface of the substrate;

[0058] optionally contacting a second metal substrate with the selected area bearing the composition; and

[0059] subsequently heating the composition at a temperature in the range of 130 to 220° C. for a time sufficient to form a cured composition bonded to the aluminum metal surface;

[0060] wherein the lap shear strength bond strength of the composition cured at 220°C is at least 80, 85, or 90% of the bond strength of the composition cured at 130°C.

[0061] Aspect 14. The method according to aspect 13, further comprising the steps of heat curing and optionally foaming by heating the composition to a temperature in the range of 120 to 140°C and maintaining the temperature in the range for a period of 10 to 60 minutes.

[0062] For various reasons, it is preferred that the composition according to the present invention, whether a one-component composition (1K) or a multi-part composition (e.g., separately packaged Part A and Part B as defined above), be substantially free of many ingredients used in prior art compositions for similar purposes. In particular, for each of the preferably minimized ingredients listed below, independently, in the order given, it is increasingly preferred that the adhesive composition according to the present invention contain no more than 1.0, 0.5, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001, or 0.0002 percent, more preferably in grams per liter, more preferably in ppm, of each of the following ingredients when in direct contact with metal in the method according to the present invention: epoxy resin or polymer, organic filler, thickener, chromium, nitrite ions, formaldehyde, formamide, hydroxylamine, ammonia; rare earth metals; elemental sulfur and / or compounds thereof; permanganate; chlorite and perchlorate; boron, such as borax, borates; strontium; and / or free chloride. Furthermore, independently for each of the preferably minimized ingredients listed below, it is increasingly preferred in the order given that the cured adhesive according to the present invention contains no more than 1.0, 0.5, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001 or 0.0002 percent, more preferably the stated amounts in parts per thousand (ppt), of each of the following ingredients: organic filler, thickener, chromium, nitrite ions, formaldehyde, formamide, hydroxylamine, ammonia; rare earth metals; elemental sulfur and / or compounds thereof; permanganate; chlorite and perchlorate; boron, such as borax, borates; strontium; and / or free chloride.

[0063] "Copolymer" refers to all polymers composed of two or more different monomers. Unless otherwise specified, there is no particular limitation on the configuration of the comonomers present in the copolymer. The copolymer can be a block copolymer, a random copolymer, an end-capped copolymer, or a telechelic copolymer.

[0064] As used herein, the term "coating" includes all similar materials that may be designated by more specialized terms such as paint, enamel, varnish, shellac, topcoat, and the like; and, unless the context clearly indicates otherwise or necessarily implies otherwise. The simple term "metal" or "metallic" will be understood by those skilled in the art to refer to a material, whether an article or a surface, consisting of atoms of a metal element (e.g., aluminum) present in an amount of at least, in the order of increasing preference, 55, 65, 75, 85, or 95 atomic percent; for example, the simple term "aluminum" includes pure aluminum, those of its alloys, and aluminum surfaces containing at least, in the order of increasing preference, 55, 65, 75, 85, or 95 atomic percent of aluminum atoms. A bare metal surface should be understood to mean a metal surface in the absence of a coating other than oxides of the metal derived from the metal surface by aging in air and / or water.

[0065] Except in the operating examples, or where otherwise indicated, all numbers used herein expressing amounts of ingredients, reaction conditions, or defining ingredient parameters should be understood as being modified in all instances by the term "about". Throughout the specification, unless expressly stated to the contrary: percentages, "parts," and ratio values ​​are by weight or mass; describing a group or class of materials as suitable or preferred for a given purpose associated with the present invention means that mixtures of any two or more members of the group or class are also suitable or preferred; descriptions of ingredients in chemical terms refer to the ingredients when added to any combination specified in the specification, or ingredients generated in situ within the composition when other ingredients are added by one or more chemical reactions between one or more newly added ingredients and one or more ingredients already present in the composition; unless otherwise indicated, molecular weight (MW) is the weight average molecular weight M wThe word "mole" means "gram mole" and the word itself and all its grammatical variations may be applied to any chemical species defined by all types and numbers of atoms present therein, whether the species is ionic, neutral, unstable, hypothetical, or actually a stable neutral species with a well-defined molecule; and the term "storage stable" or "storage stability" should be understood to include uncured compositions showing an increase in viscosity of no more than 10%, preferably less than 10%, over an observation period of at least, in order of increasing preference, 100, 1000, 1500, 2000, or 2500 hours (e.g., preferably 30, 60, or 90 days), during which the material is not mechanically disturbed and the temperature of the material is maintained at ambient room temperature in the range of about 15°C to 40°C (about 60°F to 104°F). Preferably, after storage under the conditions described above, the lap shear test performance described herein is equivalent to the initial test performance. Viscosity can be measured by means known to those skilled in the art, such as a Mooney tester, a Brookfield viscometer, or parallel plate rheology. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 A cross-sectional view of a shear test piece used in measuring the ratio of lap shear strength and strength reduction due to high-temperature heating in Examples is shown.

[0067] Figure 2 The figure shows a front view of a shear test piece used in the measurement of the lap shear strength and the ratio of the strength reduction amount due to high temperature heating in the examples. The arrow indicates the tensile direction of the test. DETAILED DESCRIPTION

[0068] A heat-curable composition according to one embodiment of the present invention comprises:

[0069] Component (a), said component (a) comprising:

[0070] (a1) at least one solid rubber; preferably based on styrene and butadiene monomers, present in an amount of about 8 to 20% by weight, based on the total weight of the composition;

[0071] (a2) at least one polymer containing olefinic double bonds that is liquid or pasty at 22° C., present in an amount of about 4 to 20% by weight based on the total weight of the composition; and

[0072] (a3) a process oil; for example, a petroleum base oil or a natural or synthetic equivalent, preferably a paraffin oil; present in an amount of about 5 to 30% by weight based on the total weight of the composition;

[0073] (a4) a liquid polydiene other than (a1) to (a3), present in an amount of about 1 to 20 weight percent based on the total weight of the composition;

[0074] and

[0075] Component (b), said component (b) comprising:

[0076] (b1) quinone dioxime in an amount of 0.1 to 5.0 wt %, preferably 0.3 to 2.0, more preferably 0.1 to 1.0, most preferably 0.15 to 0.5 wt %, based on the total weight of the composition;

[0077] (b2) an organic curing agent (preferably an organic peroxide) in an amount of 0.05 to 5.0 wt %, preferably 2.0 to 4.5 wt %, based on the total weight of the composition; and

[0078] (b3) a multifunctional coagent comprising a monomer, oligomer or polymer having multiple unsaturated reactive sites (e.g., multiple α,β-unsaturated carbonyl functional groups), wherein the multifunctional coagent is present in an amount of 0.1 to 10 wt %, preferably 0.3 to 7 wt %, based on the total weight of the composition.

[0079] Cured adhesives, sealants, or sound attenuation products can be obtained from the heat-curable compositions of the present invention when cured over a wide temperature range of about 130°C to about 200°C, and the amount of strength loss due to low- or high-temperature curing is reduced compared to similar compositions that require temperatures of 160°C to 200°C for curing. In this specification, the cured product is also described as a "cured material." As used herein, the phrase "cured product" means that the composition is largely cross-linked into a solid and no longer flowable, thereby providing good sealant and / or adhesive properties—for example, providing bond strength (lap shear test performance)—to bond substrates.

[0080] In this specification, the "heat-curable composition" is sometimes referred to simply as the "composition". In addition, in the description of the composition herein, unless otherwise specified, the amount described by "%" represents weight % based on the total weight of the composition. In this specification, unless otherwise specified, the "average molecular weight" represents the mass average molecular weight of the polymer, and is specifically obtained by converting the molecular weight using gel permeation chromatography (GPC) and using a calibration curve using polystyrene having a monodisperse molecular weight as a standard material.

[0081] The heat-curable composition according to the present invention, its components, its cured material, its use and its preparation method will be described in detail below.

[0082] Component (a): resin component

[0083] (a1) Solid rubber

[0084] As solid rubber (including thermoplastic polymers exhibiting elastomeric elasticity at room temperature (22° C.)) (a1), for example, polybutadiene-based solid rubber, styrene-butadiene rubber (styrene / butadiene / styrene copolymer (SBS)), butadiene / acrylonitrile rubber, styrene / isoprene rubber (styrene / isoprene / styrene copolymer (SIS)), styrene-ethylene / propylene-styrene copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene copolymer (SEEPS), optionally some styrene may contain a second unsaturated functional group; the amount of styrene (if present) in the above copolymers may be 10% by weight or more, more preferably 15% by weight or more, most preferably 20% by weight or more, and preferably have a styrene content of 50% by weight or less, more preferably 40% by weight or less, most preferably 30% by weight or less. Other examples of solid rubbers that can be used include synthetic or natural isoprene rubber, polyoctene, butyl rubber, and polyurethane rubber. The solid rubber (a1) may include: one solid rubber described herein, or a combination of two or more solid rubbers described herein. Preferably, in the case of using more than one solid rubber, polymers and copolymers based on different ones from one another can be chosen, which can be based on the same monomers or on different monomers.

[0085] The molecular weight and the like of the solid rubber are not particularly limited as long as they are within a range in which the solid rubber exhibits elastomer elasticity at room temperature (22° C.). For example, the Mooney viscosity (ML1+4 (100° C.)) of the solid rubber is not particularly limited, but is preferably within a range of 20 to 60, more preferably within a range of 30 to 50. The Mooney viscosity can be measured according to ASTM D1646.

[0086] Examples of "polybutadiene-based solid rubbers" include butadiene homopolymers and butadiene copolymers containing a small amount (e.g., 10 mol% or less) of monomer units other than butadiene monomers (1,3-butadiene). Examples of monomer units other than butadiene monomers include conjugated dienes such as isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 4-methylpentadiene, and 2,4-hexadiene; acyclic monoolefins such as ethylene, propylene, butene, and pentene; cyclic monoolefins such as cyclopentene, cyclohexene, and norbornene; and non-conjugated dienes such as dicyclopentadiene and 1,5-hexadiene. Furthermore, the polybutadiene-based solid rubber preferably has a high cis content, preferably having a cis-1,4-double bond content of 80% or greater, preferably greater than 85%, and most preferably 95% or greater.

[0087] In the present invention, based on the total amount of composition, solid rubber (a1) exists with the amount of at least about 8.0,8.5,9.0,9.5,10.0,10.25,10.5,10.75,11.0,11.25,11.50,11.75,12.0,12.25,12.50,12.75,13.0,13.25,13.50 or 14.0 weight % in the order that preference increases.When the content of solid rubber is 8.0 weight % or larger, it is possible to ensure the balance between intensity and flexibility characteristics. In addition, the content of solid rubber is preferably 20 weight % or less, and exists with the amount of no more than about 19.5,19.0,18.5,18.0,17.5,17.0,16.5,16.0,15.5 or 15.0 weight % in the order that preference increases. When the solid rubber content is 20% by weight or less, the viscosity of the uncured material allows pumping without adding increased amounts of plasticizer. High concentrations of plasticizer may reduce adhesion and / or may tend to leach from the formulation or cured adhesive. In embodiments where the composition is applied at elevated temperatures (greater than ambient temperature), a higher solid rubber / solid polymer content in the range of 17 to 25 or even 30% by weight may be desirable, while embodiments applied at ambient or lower temperatures may benefit from a lower solid rubber content in the range of 9.0 to 12.0% by weight.

[0088] (a2) a polymer containing olefinic double bonds that is liquid or pasty at 22°C

[0089] The one or more polymers containing olefinic double bonds that are liquid or pasty at 22°C are different from (a1) and can be selected to control the viscosity of the composition, as well as the tensile strength, elongation, and improved adhesion to aluminum of the cured material. In this specification, "polymer (a2) containing olefinic double bonds that is liquid or pasty at 22°C" is also referred to as "polymer (a2) containing olefinic double bonds." The polymer containing olefinic double bonds can be a single polymer or a mixture of two, three, four, or more polymers containing olefinic double bonds.

[0090] The polymer (a2) containing olefinic double bonds preferably has a glass transition temperature (Tg) lower than room temperature (about 20 to 30°C). In particular, the glass transition temperature can generally be about -110, -100, -95, -90, -80, -70, -60, -50, -40, -30, -20, -10, 0°C, and is preferably less than 20°C or 15°C. Here, "liquid" refers to a state in which the polymer can be poured from a container under the influence of gravity, and "paste" refers to a state in which the polymer can be smoothed into a flat, uniform layer. In addition, in this specification, the glass transition temperature refers to a value measured using "differential scanning calorimetry (DSC)" according to ASTM-D3418. The polymer can be a homopolymer or a copolymer. Mixtures of two or more polymers containing olefinic double bonds generally exhibit Tgs similar to those described above, while the individual polymers in the mixture may have a lower or higher Tg than the mixture, for example as low as -100°C or a Tg above ambient temperature, provided that the mixture is liquid or pasty at room temperature (22°C).

[0091] In one embodiment, the polymer (a2) containing olefinic double bonds may preferably be a polymer of a diene and / or an aromatic substituted olefin, and may be a copolymer of styrene and a diene from the perspective of improving the vibration damping properties of the cured material. The diene polymer may be a polydiene (e.g., polybutadiene, polyisoprene), or a mixture of polydienes, and optionally a diene copolymer.

[0092] In one embodiment, polydienes having functional groups in the main chain and / or side chain are also effective. Examples of functional groups include carboxyl groups, hydroxyl groups, and amine groups, and the polydienes may contain two or more functional groups in combination. From the perspective of adhesion to metal substrates, the liquid polydienes preferably contain carboxyl groups. The functional group should be present in at least one of the main chain and the side chain, and may be present in any position, for example, at the end or in the middle of the chain in the main chain or side chain, but is preferably present at least at the end of the chain.

[0093] The copolymer of styrene and diene, if present, preferably has a styrene content of 10% by weight or more, more preferably 15% by weight or more, and preferably has a styrene content of 50% by weight or less, more preferably 30% by weight or less. When the styrene content is within the above range, excellent dissipative vibration damping characteristics (i.e., characteristics of converting mechanical vibration energy into heat) can be achieved.

[0094] In one embodiment, the polymer containing olefinic double bonds may comprise a combination of two or more diene polymers. The diene polymer may be a homopolymer or copolymer of butadiene, isoprene, etc. The diene polymer may be cis, trans, or a mixture thereof, and may have reactive functional groups such as carboxyl groups. Preferably, one or more of the diene polymers have a majority of cis bonds. In a preferred embodiment, one of the polymers containing olefinic double bonds is or comprises a polybutadiene maleic anhydride adduct, preferably with an average molecular weight M w It may be less than 10,000, 5,000, 4,500, 3,000 daltons and at least 750, 775, 800, 850, 900 daltons. Independently preferred polybutadiene maleic anhydride adducts contain at least - in order of increasing preference - 4, 4.5, 5, 5.5, 6, 6.5, 7 wt. % and preferably not more than - in order of increasing preference - 20, 18, 16, 14, 12, 10 wt. % maleic anhydride units, based on the total weight of the maleic anhydride grafted polybutadiene.

[0095] In another embodiment of the present invention, the above-mentioned polymer containing olefinic double bonds (a2) can be preferably selected from: non-functionalized liquid polybutadiene, which contributes to viscosity and tensile properties; liquid polybutadiene with active carboxyl groups, which contributes to adhesion to aluminum; and liquid polyisoprene, which contributes to elongation and tensile properties; preferably a combination of two or more of the said polydienes.

[0096] The position of the olefinic double bonds formed in the polymer chain by diene polymerization is not particularly limited; in one embodiment focused on curing characteristics and acoustic attenuation performance, the olefinic double bond-containing polymer (a2) is formed so as to include an unsaturated diene moiety. The ratio of vinyl moieties in such diene moieties (i.e., the ratio of 1,2 vinyl bonds to all olefinic double bonds) is not particularly limited. In some embodiments, the vinyl moiety may comprise 1 to 50 mol%, preferably 1 to 16 mol%, but in some embodiments, may be as high as 70 to 80 mol%.

[0097] The mass average molecular weight of the polymer (a2) containing olefinic double bonds is not particularly limited, but is preferably 1,000 or greater, more preferably 2,000 or greater, and further preferably 5,000 or greater, and is preferably 75,000 or less, more preferably 65,000 or less, and further preferably 55,000 or less. The polymer (a2) containing olefinic double bonds particularly preferably has a mass average molecular weight within the range of 5,000 to 55,000. The polymer (a2) containing olefinic double bonds preferably has the above-mentioned structure and the above-mentioned mass average molecular weight. The polymer (a2) containing olefinic double bonds can be used alone or in combination with two or more polymers that differ from each other in one or more properties, the type and amount of the one or more monomers used, functional groups, viscosity, molecular weight, Tg and stereochemistry (cis / trans content).

[0098] Gross weight based on composition, the content of the polymkeric substance (a2) that contains olefinic double bonds is preferably at least 5 % by weight or larger, more preferably 7 % by weight or larger, to obtain enough elongations and tensile properties and to the adhesive properties of metal (particularly aluminium).In addition, gross weight based on composition, the content of the polymkeric substance (a2) that contains olefinic double bonds is preferably 15 % by weight or less, more preferably 12 % by weight or less, to keep intensity.Based on the total amount of composition, at least about 5.0,5.5,6.0,6.5,7.0,7.25,7.5,7.75,8.0,8.25,8.50,8.75,9.0,9.25,9.50,9.75,10.0,10.25,10.50 or 11.0 % by weight.When the content of the polymkeric substance that contains olefinic double bonds is at least 5.0 % by weight or larger, can realize enough crosslinked, thereby support high strength. In some embodiments, the content of the polymkeric substance containing olefinic double bonds is preferably 18 % by weight or less, and exists with the amount of no more than about 16.5,16.0,15.5,15.0,14.5,14.0,13.5,13.0,12.5 or 12.0 % by weight in the order that increases with preference.When the content of the polymkeric substance containing olefinic double bonds is 18 % by weight or less, uncured adhesive keeps the viscosity that is suitable for pumping at ambient temperature.In the embodiment that composition is used under the temperature (greater than ambient temperature) that rises, higher polymkeric substance / solid polymer content containing olefinic double bonds is in the scope of 19 to 25 or even 30 % by weight.

[0099] (a3) Petroleum-based oils or natural or synthetic equivalents

[0100] The composition of the present invention may further comprise (a3) ​​a petroleum-based oil or a natural or synthetic equivalent, preferably paraffin oil. (a3) ​​can serve as a processing lubricant, a diluent for other components or for the composition, and / or a plasticizer. When the composition comprises (a3), the processability of the composition can be improved, and the mechanical properties of the cured material can be improved. The content of the base oil (a3) ​​is not particularly limited, but is generally 40% by weight or less, preferably 30% by weight or less, and more preferably 25% by weight or less, based on the total amount of the composition, and is preferably 2% by weight or more, more preferably 5% by weight or more, for example, 15 to 20% by weight.

[0101] Examples of materials that can be used as (a3) ​​include hydrocarbon oils, such as white oils, and natural oils, which are liquid at 22°C (e.g., fatty acid glycerides, such as so-called triglycerides, such as rapeseed oil, soybean oil, walnut oil, linseed oil, sunflower oil, and olive oil) or phthalates. In one embodiment, a process oil with a lower viscosity is used. Naphthenic oil and / or paraffin oil can be used. Compared to other process oils, paraffin oil provides a composition with the lowest viscosity at the same weight percentage loading level, which is preferred. Lower viscosity allows a higher rubber to plasticizer ratio, which helps to obtain improved performance under low temperature curing. Depending on the viscosity of the selected (a3) ​​additive, the relative amounts of solid rubber and liquid rubber can be adjusted. For example, phthalates can be used in a composition with less solid rubber and more liquid rubber.

[0102] (a4) Liquid polydiene

[0103] Liquid polydiene (a4) having a low viscosity and different from (a1 to a3) can be used in the composition of the present invention. Examples of the diene monomer of the polydiene include ethylene propylene diene, butadiene, isoprene and chloroprene; examples of the polydiene oligomer or polymer include homopolymers or copolymers of optionally partially hydrogenated diene monomers, and hydroxylated derivatives of the oligomers and polymers. Among them, preferred liquid polydiene (a4) includes polybutadiene, polyisoprene, etc., and polybutadiene is particularly preferred.

[0104] In some embodiments, the liquid polydiene (e.g., polybutadiene) may preferably have a high content of cis bonds in the polymer. In one embodiment, the liquid polydiene comprises polybutadiene having a cis-1,4 double bond content of about 50% or greater. In another embodiment, the liquid polydiene preferably has a cis-1,4 double bond content of greater than 85%, most preferably 80% or greater. The liquid polydiene compound preferably has a mass average molecular weight M such that the polydiene is liquid at room temperature (22°C). w For example, the M of polydiene WIt may be in the range of 500 to 50,000 Daltons, more preferably in the range of 1000 to 10,000. Furthermore, the liquid polydiene preferably has a glass transition temperature of less than -50°C, preferably less than -60°C, most preferably less than -90°C.

[0105] The content of the liquid polydiene (a4) is preferably 3% by weight or more, more preferably 5% by weight or more, based on the total amount of the composition. Furthermore, the content of the liquid polydiene is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total amount of the composition. When the composition contains the liquid polydiene (a4) in an amount of about 3% to 20% by weight, the vibration damping properties and adhesiveness of the cured material obtained from the composition are likely to be improved.

[0106] In an alternative embodiment, the solid rubber (a1) is present in an amount of less than 8%, preferably in an amount ranging from 1 to 7%, and most preferably in an amount of less than 1%; and in a particularly preferred embodiment, the solid rubber (a1) is absent. This embodiment comprises a relatively high amount of (a4) at least one polymer containing olefinic double bonds, the polymer being selected so that it can be a low or relatively high viscosity liquid (suitable viscosities are generally less than 1200 Pa.sec@38°). Typically, the (a4) polymer in this embodiment can have a low molecular weight (1700 to 55,000 Daltons) and can be a liquid rubber, such as polybutadiene, natural rubber, isoprene rubber, SBR.

[0107] Optional hydrocarbon resin

[0108] The optional hydrocarbon resin may be added as a diluent, plasticizer, or tackifier. The content of the hydrocarbon resin is preferably 0 to 15% by weight based on the total weight of the composition; and if used, the lower limit is preferably 1% by weight or more, further preferably 5% by weight or more, and the upper limit is preferably 12% by weight or less, further preferably 10% by weight or less. When the composition contains the hydrocarbon resin, the cured material exhibits vibration damping properties as described above; and when the content is 15% by weight or less, the decrease in strength of the cured material when the composition is heated at high temperatures can be suppressed. In particular, by including the above-mentioned plasticizer and hydrocarbon resin in the composition, the sound attenuation characteristics can be improved at temperatures ranging from -5°C to 40°C.

[0109] Hydrocarbon resin can be completely aliphatic or completely aromatic, or they can have aliphatic and aromatic structure.In addition, they can be aromatic modified aliphatic resins.In each case, hydrocarbon resin particularly preferably has the compatibility with other polymer components.The example of hydrocarbon resin comprises: natural hydrocarbon resin such as terpene resin (such as terpene resin, hydrogenated terpene resin and aromatic modified terpene resin) and rosin resin (such as, rosin and modified rosin, such as hydrogenated rosin, disproportionated rosin and polymerized rosin), and synthetic hydrocarbon resin such as petroleum hydrocarbon resin, coumarone-indene resin, xylene resin and styrene resin, and among them, preferred petroleum hydrocarbon resin.

[0110] As the petroleum hydrocarbon resin, it is possible to preferably use a petroleum hydrocarbon resin obtained by partially polymerizing an unsaturated hydrocarbon monomer produced as a by-product by thermal cracking of naphtha or the like, and specific examples of the petroleum hydrocarbon resin include: C5 aliphatic petroleum resin, C9 aromatic petroleum resin, C5 / C9 petroleum resin, and a hydrogenated petroleum resin obtained by hydrogenating C9 or C5 / C9 petroleum resin, and an alicyclic petroleum resin such as dicyclopentadiene petroleum resin. These substances may be used alone or in combination of two or more thereof.

[0111] Component (b): Curing system components

[0112] (b1) Quinone dioxime

[0113] The composition according to the present invention comprises the following as a curing system having the following components: (b1) quinone dioxime in an amount of 0.1 to 5.0 wt % based on the total weight of the composition; (b2) an organic curing agent (preferably an organic peroxide) in an amount of 0.1 to 5.0 wt % based on the total weight of the composition; and (b3) a polyfunctional (preferably at least one trifunctional) (meth)acrylate monomer, oligomer, or polyol in an amount of 0 to 10 wt %, preferably 0.1 to 9 wt %, based on the total weight of the composition. The amount of quinone dioxime can be reduced or eliminated by increasing the amounts of (b2) and (b3).

[0114] Quinone dioxime (b1), a rubber crosslinker and adhesion promoter. Quinone dioxime produces crosslinks that are resistant to reversion at high temperatures (190 to 210°C). Car roofs often reach such temperatures during electrocoat curing, which can destroy crosslinks based on other curing agents (e.g., sulfur).

[0115] In some embodiments, quinone dioxime (b1) can be blended into the composition as a mixture of an active component (i.e., a compound having a curing effect (i.e., crosslinking)) and a compound other than the active component. The "content of quinone dioxime" in the present invention refers to the content of only the active component. When the content of the curing component in the composition is within the above ranges, the cured material has sufficient adhesive strength and exhibits a small decrease in strength when the composition is cured by high-temperature heating.

[0116] The compositions according to the present invention preferably contain no added elemental sulfur; trace amounts of sulfur may be present in small amounts, for example, in order of increasing preference, in amounts less than 1.0, 0.5, 0.25, 0.1, 0.05, 0.025, or 0.001 wt. %, preferably in these amounts in parts per thousand, most preferably in parts per million. Benefits of less or no elemental sulfur include better shelf life for one-pack adhesives ("1K adhesives"), and compatibility with some electrodeposition coatings (commonly referred to in the art as "electrocoat" coatings) that are sensitive to or react undesirably with sulfur-containing adhesives.

[0117] (b2) Organic peroxide curing agent

[0118] In various embodiments, the curing system is a peroxide-based curing system. In a corresponding embodiment, the at least one peroxide compound contained in the composition according to the invention is preferably selected from the group consisting of dibenzoyl peroxide, tert-butyl peroxybenzoate, and in particular 1,1-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane, butyl 4,4-di-(tert-butylperoxy)valerate, dicumyl peroxide, di-(2-tert-butylperoxyisopropyl)-benzene, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-dimethyl-2,5-dihydro-2-thiazolinone, 2,3 ... -(tert-Butylperoxy)hexane, di-tert-butyl peroxide, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, tert-butylperoxy-2-ethylhexyl carbonate, di(4-methylbenzoyl)peroxide, di(2,4-dichlorobenzoyl)peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and di-tert-butyl-1,1,4,4-tetramethylbut-2-yn-1,4-ylidene diperoxide.

[0119] In some embodiments, the amount of peroxide compound is from about 0.1 wt % to about 7 wt %, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or 7.0 wt %, based on the total weight of the composition, preferably from about 0.1 wt % to about 5 wt %, for example, about 0.15, 0.25, 0.35, 0.45, 0.55, 0.65, 0.75, 0.85, 0.95, 1.05, 1.1, 1.2, 1.4, 1.7, 1.9, 2.1, 2.4, 2.6, 2.8, 3.3, 3.7, 4.1, 4.6, 4.9, or 5.0 wt %.

[0120] In various embodiments, the curing system is a peroxide-based curing system, and the composition of the present invention comprises at least one peroxide compound in an amount of from about 0.1 wt % to about 7 wt %, preferably from about 0.1 wt % to about 5 wt %, based on the total weight of the composition. In other embodiments, the organic peroxide may be present in an amount of 2.0 to 4.5 wt %.

[0121] The present inventors have discovered that when sulfur and sulfur accelerators as described herein are absent from the cure system and the heat-curable composition comprises quinone dioxime in an amount greater than 0.1 wt%, for example, 0.2 to 0.6 wt%, in the presence of an organic peroxide, the components of the cure system synergistically achieve improved LSS results for adhesives cured on aluminum at 140°C and suppressed strength degradation of the cured material when heat-cured at elevated temperatures. In particular, when the compositions of the present invention do not comprise sulfur and sulfur accelerators conventionally used in heat-curable compositions, the observed strength degradation of the cured material due to elevated temperature heating (overbake) is within acceptable limits.

[0122] Examples of organic curing agents also include other curing systems other than those described above, provided that they do not unduly interfere with the purposes of the present invention. Examples of other vulcanization systems include quinones, nitrosobenzenes, and dinitrosobenzenes (particularly p-dinitrosobenzene). In some embodiments, dioximequinones are preferably used together with organic peroxides.

[0123] (b3) Multifunctional active additives

[0124] Based on the total weight of the composition, a multifunctional co-agent (b3) comprising a monomer, oligomer or polymer having multiple α,β-unsaturated carbonyl functional groups can be included in the composition in an amount of 0.1 to 10 weight %. Desirably, the multifunctional co-agent comprises multiple unsaturated reactive sites, which are not particularly limited. In some embodiments, the unsaturated sites comprise two, three or more α,β-unsaturated carbonyl functional groups, such as multiple (meth)acrylate terminal functional groups, preferably multifunctional acrylates and methacrylates. Multifunctional (meth)acrylates can be di-, tri- or more substituted, which means that the molecule has 2, 3 or more ethylenic unsaturated sites. In one embodiment, (b3) includes trimethacrylate, triacrylate, diacrylate, dimethacrylate or a combination of two or more of these co-agents. In some embodiments, the (meth)acrylate terminal functional groups are separated by linear or branched C2-C12 alkyl groups, or by one or more EO or PO groups.

[0125] The multifunctional (meth)acrylate monomers, oligomers or polymers (b3) are not particularly limited, provided that they do not adversely affect low temperature curing, storage stability, anti-reversion properties or other objects of the present invention. Examples of (b3) materials may include: monomers such as trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), ethylene dimethacrylate (EDMA), diethylene glycol dimethacrylate (EGDMA), ethylene glycol dimethacrylate (DEGDMA), pentaerythritol tri(meth)acrylate (PETRA; PETRMA) and pentaerythritol tetraacrylate (PETTA); 1,1,1-tris[4-(2'-hydroxy-3'-methacryloyloxypropoxy)phenyl]ethane (THMPE) and 1,1,1-tris[4-(2'-hydroxy-3'-methacryloyloxypropoxy)phenyl]methane (THMPM); hydroxyl-functional monomers such as 3-(acryloyloxy)-2-hydroxypropyl methacrylate. Polyfunctional (meth)acrylate oligomers and polymers may also be used, for example alkoxylated trimethylolalkane tri(meth)acrylates, such as ethoxylated (3) trimethylolpropane triacrylate (EO3), propoxylated (3) trimethylolpropane triacrylate (PO3). Preferred are di-(meth)acrylates and tri-(meth)acrylates, which are understood to mean members of the group of di-acrylates and tri-acrylates and di-methacrylates and tri-methacrylates, desirably having a molecular weight of at least about 198 and up to about 500 daltons. Trimethylolpropane triacrylate (TMPTA), ethoxylated (3) trimethylolpropane triacrylate (EO3), propoxylated (3) trimethylolpropane triacrylate (PO3), ethylene dimethacrylate (EDMA) and ethylene glycol dimethacrylate (EGDMA) are commonly used.

[0126] In certain embodiments of the composition of the present invention, the heat-curable composition and its cured product may contain one or more additives, such as a blowing agent (optionally present), one or more fillers, flame retardants, colorants (such as carbon black), hygroscopic agents, antioxidants and plasticizers, etc., which can be used in combination with the above components.

[0127] Component (c): foaming agent

[0128] In one embodiment of the present invention, the composition may contain a blowing agent to cause irreversible expansion (foaming) before or during thermal curing, and preferably contains: (c1) a physical blowing agent in an amount of 0 to 3 wt % based on the total weight of the composition, and (c2) a chemical blowing agent in an amount of 0 to 4 wt % based on the total weight of the composition. The irreversible expansion of the blowing agent results in an irreversible volume increase, which allows the cavities or intermediate spaces to be more completely filled with the cured compound. For highly expansive materials, chemical blowing agents with expansion of 100% or more are preferred.

[0129] The content of the (c1) physical foaming agent in the composition is not particularly limited, but the content is preferably 0 to 3 wt %, more preferably 0.1 to 2.5 wt %, and further preferably 0.2 to 2.0 wt %, based on the total weight of the composition.

[0130] As "physical foaming agent", preferably a resin foaming agent (heat-expandable resin foaming agent) that expands by heating, and more preferably expandable plastic hollow microspheres that expand by heating. The physical foaming agent that can be used in the present invention can be composed of heat-expandable microspheres that accommodate low-boiling point liquid hydrocarbons inside the thermoplastic polymer shell. When heated, the shell softens and the hydrocarbons accommodated inside expand at the same time, thereby forming microspheres (micro-balloons). Examples of heat-expandable resin foaming agents include those based on polyvinylidene chloride copolymers or acrylonitrile / (meth)acrylate copolymers. These substances are commercially available, for example, can be obtained from Pierce & Stevens and Casco Nobel under the name "Dualite (registered trademark)" or "Expancel (registered trademark)".

[0131] (c2) Examples of “chemical foaming agents” include those that release gas by decomposition and are generally referred to as exothermic foaming agents and endothermic foaming agents. Exothermic foaming agents include azobisisobutyronitrile, azodicarbonamide, dinitrosopentamethylenetetramine, 4,4′-oxybis(benzenesulfonic acid hydrazide), diphenylsulfone-3,3′-disulfohydrazide, benzene-1,3-disulfohydrazide, and p-toluenesulfonyl semicarbazide.

[0132] Endothermic chemical blowing agents are typically: bicarbonates, solid, optionally functionalized, polycarboxylic acids and their salts, and mixtures thereof. Suitable bicarbonates are those of the formula XHCO3, where X can be any cation, in particular an alkali metal ion, preferably Na + or K + , where Na + is highly preferred. Other suitable cations X + Can be selected from NH4 + 、1 / 2Zn 2+ 、1 / 2Mg2+ 、1 / 2Ca 2+ and mixtures thereof. Particularly preferred is the use of sodium bicarbonate and / or potassium bicarbonate, in particular sodium bicarbonate. Suitable polycarboxylic acids include, but are not limited to, solid, organic di-, tri-, or tetracarboxylic acids, in particular hydroxy-functionalized or unsaturated di-, tri-, tetra-, or polycarboxylic acids, such as citric acid, tartaric acid, malic acid, fumaric acid, and maleic acid. Citric acid is particularly preferred. One of the benefits of citric acid is that it is an environmentally sustainable propellant.

[0133] The salts of the acids and mixtures of two or more of the described compounds are also suitable. In the case of salts of polycarboxylic acids, the counterion is preferably selected from Na + , K + NH4 + 、1 / 2Zn 2+ 、1 / 2Mg 2+ 、1 / 2Ca 2+ and mixtures thereof, wherein Na + and K + , especially Na + In particular, salts of polycarboxylic acids exhibit a shift in decomposition temperature towards higher temperatures, making it possible to adjust a wide temperature range for decomposition by blending. When using polycarboxylic acids, carbonates can also be used in addition. Mixtures of bicarbonates and carbonates with polycarboxylic acids are preferred, as this allows for the development of particularly different activation stages and decomposition reactions.

[0134] Particularly preferred blowing agents are sodium bicarbonate and / or citric acid / citrate salts, and most preferably a mixture of sodium bicarbonate and citric acid. Such a mixture has a low onset temperature of only 120 to 140°C compared to conventional exothermic blowing agents such as ADCA or OBSH, wherein OBSH has an onset temperature of 140 to 160°C, and ADCA is activated with zinc salts, which has an onset temperature of 160 to 170°C.

[0135] To help lower the onset temperature of ADCA or OBSH, urea can be included in these blowing agents in an amount of about 0.1 to 0.5 wt %. It is reported that the dp temperature (°C) of ADCA can be lowered to a range of 148°C to 152°C, and the dp temperature (°C) of OBSH can be lowered to a range of 127°C to 129°C.

[0136] The endothermic blowing agent may be a mixture of a polycarboxylic acid and an inorganic carbonate, wherein the polycarboxylic acid and the inorganic carbonate have each been surface-treated with a component that prevents water from being absorbed therein.

[0137] The content of the (c2) chemical foaming agent in the composition is preferably 0 to 0.2 wt %, more preferably 0 to less than 0.2 wt %, based on the total weight of the composition; and the composition further preferably does not contain (i.e., contains 0 wt % of) the (c2) exothermic chemical foaming agent. The inventors of the present invention have found that when the content of the chemical foaming agent commonly used as a foaming agent in a heat-curable composition is preferably 0.2 wt % or less, more preferably less than 0.2 wt %, and the composition further preferably does not contain a chemical foaming agent, the reduction in strength of the composition due to high-temperature curing can be suppressed. Therefore, when the composition of the present invention contains a foaming agent, an aspect is particularly preferred in which the composition contains a physical foaming agent and does not contain a chemical foaming agent. It is also preferred that the composition contains less than 0.05 wt % of an exothermic chemical foaming agent, in particular azodicarbonamide or 4,4'-oxybis(benzenesulfonylhydrazide).

[0138] In the embodiment of the present invention, whether or not to use a foaming agent can be appropriately selected depending on the use of the composition, etc. For example, when used for manufacturing a vehicle, it is effective that the composition foams during the baking-curing step to reduce strain in the outer skin, and therefore the foaming agent is desirably added in an appropriate range.

[0139] Component (d): filler

[0140] The composition of the present invention may contain a filler (d). The filler content is not particularly limited, but the lower limit is preferably 10% by weight or more, more preferably 15% by weight or more, and further preferably 25% by weight or more, based on the total amount of the composition, and the upper limit is preferably 50% by weight or less, more preferably 45% by weight or less, further preferably 40% by weight or less, and still further preferably 36% by weight or less.

[0141] Filler can be selected from various materials, and the example of filler includes fumed silica, chalk, natural calcium carbonate, precipitated calcium carbonate or ground calcium carbonate, calcium magnesium carbonate, silicon dioxide, talc, mica and barite. In one embodiment, at least some of the filler can be surface treated. For example, in order to reduce the moisture absorbed in the cured material, and in order to reduce the moisture sensitivity of the cured material, the filler is preferably coated with stearic acid, and its example includes calcium carbonate and chalk coated with stearic acid. In one embodiment, fillers with high aspect ratio can be used, such as flaky fillers with a thickness smaller than the size of the sheet surface. As flaky fillers, from the perspective of providing good sound attenuation characteristics, preferably fillers with an aspect ratio of 10 or more (that is, a thickness in a direction perpendicular to the sheet surface is 1 / 10 of the minimum area of ​​the sheet surface or less), such as layered silicates (preferably mica and talc) and graphite. It is also possible to use ordinary inorganic lightweight aggregates (glass hollow microspheres, ceramic hollow microspheres, etc.) for adjusting specific gravity.

[0142] In addition to the above fillers, the composition of the present invention may further comprise calcium oxide in an amount of 0 to 10 wt %, preferably 1 to 6 wt %, and more preferably 1.5 to 5.5 wt % for binding moisture, based on the total amount of the composition.

[0143] In addition, the composition of the present invention may contain carbon black. Based on the total weight of the composition, the content of carbon black is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, and preferably 3 wt% or less, more preferably 2 wt% or less.

[0144] The composition of the present invention may optionally further comprise a fiber reinforcing filler, preferably short organic, glass or carbon fibers in the form of pulp fibers or short fibers. The fiber content of the composition is not particularly limited, but is preferably 0.5 to 10% by weight based on the total amount of the composition.

[0145] The composition of the present invention comprises component (a) and component (b) described above, and further preferably comprises at least one selected from the group consisting of: (c) a blowing agent, (d) a filler, and a plasticizer / processing oil. In some embodiments, no blowing agent or fibrous filler is present. In other embodiments, the composition comprises all of (c) a blowing agent, (d) a filler, and a plasticizer / processing oil.

[0146] Examples of aspects of the components constituting the heat-curable composition of the present invention are shown in Table 1, but the present invention is not limited thereto.

[0147] Table 1

[0148]

[0149] *Amounts are given in % based on the total weight of the composition and the total component amount does not exceed 100% of the composition.

[0150] The composition of the present invention is not limited to the composition described in Table 1 above, and the amounts of the components blended may be varied; and in addition to or in place of any of the components exemplified above, the composition may contain fibers, another typical curing accelerator and / or crosslinking agent, another antioxidant, a co-activator, a catalyst, oil, resin, anti-aging agent, rheological additive, adhesion promoter, pigment, thermoplastic polymer and / or the like.

[0151] The composition of the present invention can be prepared, for example, by introducing the components described above into a mixer (eg, a bead mill, attritor, jar mill, three-roll mill, rotary mixer, or twin-screw mixer) and mixing them at a temperature below that required to initiate curing.

[0152] The composition of the present invention is a mixture of multiple components that are liquid or solid at 22°C, and has the advantage that the mixing ratio of the components can be appropriately adjusted within a range that does not impair the effects of the present invention. Therefore, in one embodiment of the present invention, the ratio of the components can be adjusted so that the composition can be mechanically applied (e.g., by robot) or manually at a temperature of 60°C or lower using standard coating equipment used in the adhesive and sealant manufacturing industry. To this end, it is preferred that: the sound attenuating resin described above is liquid or pasty at 22°C; and as described in detail above, the solid rubber, sound attenuating resin, hydrocarbon resin, and liquid polydiene are blended in the preferred ratio. Therefore, the composition according to the preferred embodiment of the present invention has a viscosity at a temperature within the range of 15 to 60°C that allows it to be pumped using a pump (rotary pump, gear pump, or lift piston pump). According to this embodiment of the present invention, it is advantageous that no special extrusion technology is required, and no injection molded articles, etc., need to be prefabricated.

[0153] Another aspect of the present invention relates to a method for applying the composition of the present invention. Thus, the present invention relates to a method for applying the composition of the present invention, which method comprises injecting the composition of the present invention at a temperature in the range of 15 to 60° C. to the application point by means of a pump (e.g., the pump described above), thereby applying the composition in a liquid or pasty state to a lubricated substrate, an untreated substrate, or a clean substrate.

[0154] After application, the composition according to the invention can be cured thermally, using ovens commonly available in the vehicle and equipment construction industry for baking paint coatings. The activation temperature for thermal curing and, if applicable, foaming is preferably in the range of 130 to 220° C. This temperature is preferably maintained for a period of 10 to 30 minutes.

[0155] In addition to the present composition used in pump applications, shaped articles that are baked and cured materials of the present composition can also be used as modified parts in trim shops (assembly steps), aftermarkets (repair markets), and the like.

[0156] Another aspect of the present invention relates to a cured product (cured material) obtained by curing the composition according to the present invention. The cured material according to an embodiment of the present invention has excellent vibration damping properties (sound attenuation properties) and a small amount of strength reduction caused by heating at high temperatures.

[0157] In an embodiment of the present invention, the cured material preferably has a glass transition temperature in the range of -20 to 40°C, preferably in the range of -15 to 30°C. When the glass transition temperature is within the above range, good vibration damping characteristics (sound attenuation behavior) are obtained over a wide temperature range. The glass transition temperature of the cured material can be defined as the temperature at which the loss factor (tan δ) is maximum.

[0158] Cured products according to embodiments of the present invention can be prepared by heating the composition of the present invention, for example, at a temperature in the range of 130 to 220° C. for 10 to 30 minutes. Here, the composition can be applied directly to the site of use before curing, or it can be processed to form a baked and cured product for use as a retrofit part.

[0159] Another aspect of the present invention relates to the use of the composition according to the present invention and its cured material. The composition of the present invention can preferably be used as a gasket material and adhesive / sealant, in particular for structural attachments (e.g., doors, hoods and trunk lids, roofs, front and chassis parts), and further for use in the passenger compartment of vehicles (cars, buses, etc.), and for the production of rail cars. In addition, when acoustic vibrations (usually from vibrations generated by rotating machines) that should be attenuated from motors, gears or pumps, the composition of the present invention can also preferably be used in equipment construction. Therefore, the present invention relates to the use of the composition of the present invention as a sound attenuating material, adhesive and / or sealant in vehicle and equipment construction.

[0160] Example

[0161] The present invention will be described in more detail below by way of examples, but the present invention is not limited to these examples.

[0162] Examples 1 to 6

[0163] The components were mixed in the amounts shown in Table 2 to prepare the compositions of Examples 1 to 6. The lap shear strength of each of the prepared compositions was tested as described.

[0164] Table 2

[0165]

[0166] Lap shear strength test

[0167] The compositions of Examples 1 to 6 were each tested on X621 aluminum as follows:

[0168] X621 aluminum plates with a thickness of 0.8 mm and a size of 100 mm × 25 mm were washed, anti-rust oil was applied, and the composition was applied to one plate with a thickness of 3 mm and an area of ​​25 mm × 25 mm; a second plate was applied to the composition, as Figure 1 and 2 As shown in . Figure 1 is a cross-sectional view of the shear test piece, and Figure 2 3 is a front view of the shear test piece used. For Examples 1 to 5, a separate shear test piece was made for each example for the different curing temperatures to be applied shown in Table 3. The shear test pieces were cured at the temperatures and held for 20 minutes. For Example 6, four separate shear test pieces were made, one for each curing temperature. Each of the four test pieces of Example 6 was baked under the curing conditions shown in Table 3 and held for 20 minutes, wherein the Example 6 plate cured at 170°C, 190°C or 290°C was overbaked to test whether high-temperature heat curing (high heat cure) would reduce adhesive strength or cohesive strength. Each shear test piece was allowed to cool to ambient temperature. Thereafter, a universal tensile tester was used to evaluate the lap shear strength at the time of bond failure. Each shear test piece was subjected to a force applied at a controlled rate until the bond broke, and the maximum force applied was recorded. The movement speed of the fixture was 50 mm / min. For Examples 1 to 6, a visual qualitative comment on the failure mode was made based on the amount of adhesive remaining on the aluminum substrate after the bond failed (more adhesive showed cohesive failure, which is better performance). LSS results are given in kilopascals (kPa).

[0169] Table 3 Lap shear strength (LSS)

[0170]

[0171]

[0172] The above test results tend to indicate that some of the compositions of the present invention cured at temperatures of 130°C to 150°C (which is lower than standard oven cure at 160°C to 200°C) exhibited A or B grade performance and good LSS test results. When cured at 140°C, Example 6 outperformed Examples 1 to 4, exhibiting an LSS of 270 kPa*s. A small decrease in LSS score was observed for Example 6 panels that were overbaked in the 170°C, 190°C or 290°C range on aluminum. Throughout the overbake temperature window, the overbaked panels exhibited significantly better LSS than Examples 3 and 4. Compositions cured at low temperatures that exhibit overbake resistance are highly desirable in production line operations where line stops may result in overbake conditions.

[0173] Examples 6 to 12

[0174] In this set of examples, the effects of increasing the amounts of organic peroxide and multifunctional (meth)acrylate monomer and decreasing the amount of quinone dioxime were examined. The components were mixed in the amounts shown in Table 4 to prepare the compositions of Examples 6 to 12.

[0175] Table 4

[0176]

[0177]

[0178] Lap shear strength results in MPa

[0179] Curing conditions Ex.7 Ex.8 Ex.9 Ex.10 Ex.11 Ex.12 Ex.13 LSS-6111Al; 140℃ 0.32 0.64 0.84 0.76 0.86 0.84 0.46 LSS-6111Al; 135℃ 0.28 LSS-6111Al; 130℃ 0.28

[0180] Lap Shear Strength Test (LSS)

[0181] Each of the compositions of Examples 6 to 12 was tested on 6111 aluminum as follows: a 6111 aluminum plate having a thickness of 0.8 mm and dimensions of 100 mm x 25 mm was washed, rust preventative oil applied, and the composition was applied to one plate at a thickness of 3 mm and an area of ​​25 mm x 25 mm; a second plate was applied to the composition as previously described. Figure 1 and 2 As shown in Table 4. Each shear test piece was baked under the curing conditions shown in Table 4 and held for 20 minutes. Individual shear test pieces of the composition of Example 6 were cured at the three different temperatures shown. Each shear test piece was allowed to cool to ambient temperature. Thereafter, using a universal tensile tester, each shear test piece was subjected to a force applied at a controlled rate until the bond broke, and the maximum force was recorded. The movement speed of the fixture was 50 mm / min. The LSS results are given in MPa.

[0182] The present invention can be used in all industrial sectors requiring adhesives and sealants which achieve complete cure at oven temperatures of 130 to 150° C. with a cure time of about 10 to 30 minutes, preferably up to 20 minutes, and which exhibit a small proportion of the strength loss due to high-temperature curing, that is, curing temperatures of 190 to 210° C. The compositions according to the invention can be used particularly effectively in the vehicle and equipment construction industry.

Claims

1. A heat-curable composition comprising: Component (a), said component (a) comprising: (a1) solid rubber; (a2) a polymer containing olefinic double bonds which is liquid or pasty at 22°C; (a3) process oils; and (a4) a liquid polydiene other than (a1 to a3); and Component (b) comprises a vulcanization system of two or more of the following: (b1) quinone dioxime; (b2) Organic peroxides and (b3) A multifunctional coagent comprising a monomer, oligomer or polymer having multiple α,β-unsaturated carbonyl functional groups.

2. The heat-curable composition according to claim 1, further comprising component (c), wherein the component (c) comprises: (c1) a physical blowing agent in an amount of 0 to 3 wt % based on the total weight of the composition; (c2) a chemical blowing agent in an amount of 0 to 4.0 wt %, based on the total weight of the composition; and (c3) a urea-based blowing agent accelerator in an amount of 0 to 1 wt %.

3. The heat-curable composition according to claim 1, wherein the vulcanization system (b) is: (b2) an organic peroxide present in an amount of 0.2 to 2.0 weight percent based on the total weight of the composition; and (b3) a multifunctional coagent present in an amount of 0.3 to 7 weight percent based on the total weight of the composition.

4. The heat-curable composition according to claim 2, wherein the amount of (c1), (c2) and (c3) is 0 wt% based on the total weight of the composition.

5. The heat-curable composition according to claim 1, wherein the polymer containing ethylenic double bonds (a2) comprises polybutadiene grafted with about maleic anhydride and has a mass average molecular weight of 10,000 to 750 Daltons.

6. The heat-curable composition of claim 5, wherein the polybutadiene grafted with maleic anhydride (a2) comprises 4 to 20 pbw of maleic anhydride moieties.

7. The heat-curable composition according to claim 1, wherein the (a3) ​​processing oil comprises paraffin oil in an amount of 5 wt% to 30 wt% based on the total mass of the composition.

8. The heat-curable composition according to claim 1, wherein the (a4) liquid polydiene different from (a1 to a3) is a polybutadiene polymer having a mass average molecular weight of 1,000 to 50,000 g / mol.

9. The heat-curable composition according to claim 1, wherein the (b3) multifunctional coagent comprising a monomer, oligomer or polymer having a plurality of α,β-unsaturated carbonyl functional groups comprises at least one trifunctional (meth)acrylate.

10. The heat-curable composition according to claim 1, wherein: The (a1) solid rubber is present in an amount of about 8 to 20 weight % based on the total weight of the composition; The (a2) polymer containing olefinic double bonds that is liquid or pasty at 22° C. is present in an amount of about 5 to 15% by weight based on the total weight of the composition; the (a3) ​​processing oil is present in an amount of about 5 to 30 weight percent based on the total weight of the composition; The (a4) liquid polydiene different from (a1) to (a3) ​​is present in an amount of about 3 to 20 weight percent based on the total weight of the composition; the (b1) quinone dioxime is present in an amount of 0.1 to 5 wt % based on the total weight of the composition; The (b2) organic curing agent is an organic peroxide, which is present in an amount of 0.05 to 5.0% based on the total weight of the composition; and The (b3) multifunctional coagent is present in an amount of 0.1 to 10 wt % based on the total weight of the composition; and The heat-curable composition further comprises the following substances as additional components: calcium oxide present in an amount of 0.1 to 6% by weight; and fillers present in a total amount of 10 to 50% by weight; All weight % amounts are based on the total mass of the composition; and The components are selected such that the heat curable composition has a viscosity such that the composition can be pumped at a temperature in the range of 15 to 60°C.

11. The heat-curable composition according to claim 1, further comprising a filler (d) in an amount of 10 to 45 wt% based on the total weight of the composition.

12. An article comprising a component having a metal surface, wherein the metal surface is preferably an aluminum surface, and adhered to the metal surface is a composition according to claim 1, which is cured at a temperature in the range of 120 to 140°C for a time in the range of 10 to 20 minutes to form an adhesive bond between two parts of the article and / or seal the surface of the article, wherein the article is a component of a vehicle, equipment, tool or aircraft.

13. A method for applying an adhesive or sealant to a metal substrate having at least one aluminum metal surface, comprising the steps of: delivering the composition according to claim 1 to the point of application at a temperature in the range of 15 to 60° C., preferably by means of a pump; depositing the composition in a liquid or paste state onto selected areas of the first aluminum metal surface of the substrate; optionally contacting a second metal substrate with the selected area bearing the composition; and subsequently heating the composition at a temperature in the range of 130 to 220° C. for a time sufficient to form a cured composition bonded to the aluminum metal surface; The lap shear strength bond strength of the composition cured at 220°C is preferably at least 30, 40, 50, 60, 70, 80, 90% of the bond strength of the composition cured at 130°C.

14. The method of claim 14, further comprising the step of heat curing and optionally foaming by heating the composition to a temperature in the range of 120 to 140°C and maintaining said temperature range for a period of time of 10 to 60 minutes.

Images