Modified rubber emulsion and water-based adhesive composition

Abstract

The invention relates to the technical field of water-based adhesives, in particular to a modified rubber emulsion and a water-based adhesive composition, which are prepared from the following raw materials in percentage by mass: 10 to 70 percent of modified rubber solution, 0.01 to 5 percent of surfactant and the balance of water, a water-based adhesive composition prepared from the modified rubber emulsion effectively meets the application requirement for bonding between metal and an elastomer, and the product is environmentally friendly, has excellent stability, also has the performance of bonding a base material and the elastomer in a single coating manner, and has extremely high market application and popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of water-based adhesives, in particular to modified rubber emulsions and water-based adhesive compositions. Background Art

[0002] Many commercially available compositions for bonding metal-elastomers are dissolved in organic solvents, which may cause damage to the environment and may affect the health of workers exposed to the solvents. In view of the increasing awareness of environmental protection and environmental safety, there is an urgent need for a low-VOC or VOC-free adhesive composition to avoid the use of organic solvents. However, most of the water-based adhesive compositions currently used for metal-elastomer bonding do not comply with the volatile matter content of ≤50g / L specified in GB33372-2020, and some products even contain chlorinated solvents (the United States has revised the relevant laws and regulations on the "Toxic Substances Control Act Dichloromethane", and explicitly prohibited the use of dichloromethane in industry and commerce; the European Union's revised "Registration, Evaluation, Authorization and Restriction of Chemicals" also imposes relevant restrictions on chlorinated solvents, such as dichloromethane, chlorobenzene, chloroform, etc.), so it is very necessary to develop a water-based adhesive composition that complies with relevant laws and regulations.

[0003] At present, there are two major systems in water-based adhesives. One is a water-based adhesive with copolymer emulsions with dichloroprene as the main monomer, acid absorbers, nitroso compounds, and film-forming agents as the main components; the other is a water-based adhesive with halogenated polyolefin emulsions, acid absorbers, nitroso compounds, and maleimide compounds as the main components. The former has good performance in terms of adhesion to natural rubber, short-term environmental resistance, and storage stability, but its versatility for bonding elastomers is problematic, and most adhesives contain chlorinated solvents; for example, a Chinese patent (publication number CN1135224A) discloses an adhesive composition containing a polyvinyl alcohol-stabilized butadiene copolymer emulsion and a methylene donor; a US patent (publication number US8501853B2) discloses an adhesive composition containing a butadiene polymer latex, an acid scavenging compound, and substantially no phenolic resin or methylene donor compound (γ-PO M); U.S. Patent (Publication No. US4483962) discloses a ternary polymer latex prepared by emulsion polymerization of a mixture of 2,3-dihalo-1,3-butadiene and at least two different unsaturated monomers; Chinese Patent (Publication No. CN1135224A) discloses an adhesive composition containing a polyethanol-stabilized butadiene polymer latex and a methylene donor compound, etc., which are prone to bonding failure when bonding non-polar rubbers, and the types of bonding elastomers are relatively small, and do not have the performance of single-coating bonding substrates and elastomers. The latter has better environmental resistance and is more universal in its selectivity for elastomers, but there are differences in storage stability and high temperature resistance. In addition, the performance of single-coated bonding substrates and elastomers cannot achieve the same performance as solvent-based adhesive compositions; for example, a Chinese patent (authorization publication number CN101182404B) discloses an aqueous adhesive composition; a Chinese patent (authorization publication number CN112585229B) discloses a water-based adhesive film-forming covering composition; a Chinese patent (authorization publication number CN1908105B) discloses an aqueous composition as an adhesive; a Chinese patent (authorization publication number CN1055488C) discloses a water-based adhesive composition containing a chlorosulfonated polyethylene latex, a polymaleimide compound, a nitroso compound and a metal oxide, etc., but the resistance to harsh environments is insufficient, the storage stability is relatively poor, and the 12-month shelf life expected by customers cannot be achieved.

[0004] Therefore, the current water-based adhesive composition has obvious deficiencies in bonding performance compared to conventional solvent-based adhesive compositions, and cannot provide the same bonding performance as solvent-based adhesives to meet the bonding application requirements between metal and elastomer. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a modified rubber latex. The aqueous adhesive composition prepared by the modified rubber latex can effectively meet the bonding application requirements between metals and elastomers. The product is environmentally friendly and has excellent stability. At the same time, it also has the performance of single-coating bonding substrates and elastomers, and thus has extremely high market application and promotion value.

[0006] On one hand, the present invention provides a modified rubber latex, wherein the raw materials for its preparation at least include, by mass percentage, 10-70% of modified rubber solution, 0.01-5% of surfactant, and the balance of water, wherein the modified rubber solution is prepared by modifying a halogenated elastomer with a modifier.

[0007] As a preferred technical solution, the modified rubber latex, in terms of mass percentage, comprises at least the following raw materials: 40-60% of modified rubber solution, 0.5-5% of surfactant, and the balance of water.

[0008] Most preferably, the modified rubber latex, in terms of mass percentage, is prepared from the following raw materials: 49.00% of modified rubber solution, 1.00% of surfactant A, and the balance of water.

[0009] As a preferred technical solution, the raw materials for preparing the modified rubber solution include at least the following components by mass percentage: 10-20% of halogenated elastomer, 0.5-2% of modifier, and the balance of solvent.

[0010] As a preferred technical solution, the halogenated elastomer is selected from at least one of halogenated natural rubber and halogen-containing synthetic rubber.

[0011] Preferably, the halogen-containing synthetic rubber includes at least one of polychloroprene, halogenated polychloroprene, halogenated polybutadiene, hexachloropentadiene, butadiene-halogenated cyclic conjugated diene adducts, halogenated butadiene styrene copolymers, halogenated ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene terpolymers, halogenated polyethylene, halogenated sulfonated polyolefins, halogenated poly(2,3-dichloro-1,3-butadiene), copolymers of α-halogenated acrylonitrile and 2,3-dichloro-1,3-butadiene, and halogenated polyvinyl chloride, and is preferably halogenated sulfonated polyolefins.

[0012] Preferably, the halosulfonated polyolefin includes at least one of chlorosulfonated polyethylene, bromosulfonated polyethylene, chlorosulfonated polypropylene and bromosulfonated polypropylene, preferably chlorosulfonated polyethylene or bromosulfonated polyethylene.

[0013] Preferably, the weight average molecular weight of the chlorosulfonated polyethylene is 30,000 to 150,000, preferably 60,000 to 120,000.

[0014] Preferably, the Mooney viscosity (ML (1+4) @ 100°C) of the chlorosulfonated polyethylene is 45-100, preferably 45-60.

[0015] Preferably, the chlorine content of the chlorosulfonated polyethylene is 20 to 50 wt%, preferably 30 to 40 wt%.

[0016] Preferably, the sulfur content of the chlorosulfonated polyethylene is 0.25 to 5 wt%, preferably 0.8 to 2.0 wt%.

[0017] As a preferred technical solution, the modifier is selected from at least one of the structures shown in formula (1) to formula (4),

[0018] Formula (1): R——OH, where R represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 n-valent straight-chain or branched alkynyl, C6~C 40 An n-valent aromatic group; any -H or -CH3 in R may be replaced by an oxygen atom, a halogen atom, a cyano group or a methoxy group.

[0019] It should be noted that the "n-valent" in the term "n-valent alkyl" means that there are n substituents on the alkyl group. Similarly, "n-valent alkenyl" and "n-valent alkynyl" respectively mean that there are n substituents on the alkenyl group and n substituents on the alkynyl group. Other expressions of "n-valent groups" involved in this patent are subject to the same interpretation.

[0020] Preferably, formula (1) comprises at least one of methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, tert-butanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, 2-methoxyethanol, 2-butoxyethanol, 2-ethoxyethanol, 2-butoxypropanol, 2-butoxyethoxyethanol, 2-bromopropanol, 3-bromopropanol, propoxypropanol, propylene glycol monomethyl ether, n-dodecyl alcohol, 4-butyn-1-ol, polyethylene glycol monomethyl ether, ethanolamine, propanolamine, and isopropanolamine.

[0021] Formula (2): Where R1 represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 n-valent straight-chain or branched alkynyl, C6~C 40an n-valent aromatic group, R2 represents a methyl group or a hydrogen atom; any -H in R1 may be replaced by a halogen atom, any -CH3 in R1 may be replaced by a methoxy group or a cyano group, and any -CH2- in R1 may be replaced by an oxygen atom or a sulfur atom.

[0022] Preferably, formula (2) comprises at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate.

[0023] Formula (3):

[0024] Formula (4): Where R represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 an n-valent straight-chain or branched alkynyl group or a halogen atom; any -H or -CH3 in R may be substituted by an oxygen atom, a halogen atom, a cyano group or a methoxy group.

[0025] Preferably, formula (4) comprises at least one of phthalamide, 4-methylphthalamide, 3-ethylphthalamide, N-hydroxyethylmaleimide, and 1-hydroxy-1H-pyrrole-2,5-dione.

[0026] As a preferred technical solution, the modifier is selected from any one of anhydrous ethanol, anhydrous methanol, polyethylene glycol monomethyl ether, ethanolamine, maleimide, hydroxyethyl acrylate, 2-bromoethanol, and 3-hydroxypropionitrile.

[0027] As a preferred technical solution, the solvent at least includes xylene.

[0028] As a preferred technical solution, the raw materials for preparing the modified rubber solution also include an alkaline catalyst.

[0029] As a preferred technical solution, the alkaline catalyst is selected from at least one of amino metal compounds, alkaline metal hydroxides, alkaline metal carbonates, alkaline metal bicarbonates, and alkaline organic amine compounds.

[0030] Preferably, the alkaline catalyst is selected from at least one of lithium isopropylamide, lithium hexamethylenedisilazide, lithium trisilylamide, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, calcium bicarbonate, potassium bicarbonate, triethylamine, and diethylamine.

[0031] As a preferred technical solution, the molar ratio of the alkaline catalyst to the modifier is (1-5):1, preferably (1-1.2):1.

[0032] As a preferred technical solution, the method for preparing the modified rubber solution comprises the following steps: mixing the raw materials for preparing the modified rubber solution, and reacting at 30 to 100° C. for 3 to 10 hours to obtain the modified rubber solution.

[0033] Preferably, the reaction temperature is 50-90° C., and the reaction time is 5-8 h.

[0034] The surfactant A is selected from at least one of carboxylates, acyl derivatives of sarcosine, sulfates, sulfated natural oil esters, alkyl aryl polyether sulfates, alkali metal alkyl sulfates, ethoxylated aryl sulfonates, alkyl aryl polyacyl sulfonates, cumene sulfonates, sulfosuccinates, phosphates, ethoxylated (ethylene oxide) derivatives, alcohols, ethylene oxide / propylene oxide block copolymers, stearates, dehydration products of sorbitol, amines, lauric acid and isopropenyl halides.

[0035] Carboxylates that may be cited include: fatty acid soaps derived from lauric acid, stearic acid and oleic acid; acyl derivatives of sarcosine include: methylglycine; sulfates include: sodium lauryl sulfate; sulfated natural oil esters include: Turkey red oil; phosphates include: short-chain fatty alcohol partial esters of complex phosphates and orthophosphates of polyethoxylated fatty alcohols; stearic acid esters include: glycerol monostearate; dehydration products of sorbitol include: dehydrated sorbitan monostearate and polyethylene oxide dehydrated sorbitan monolaurate.

[0036] Preferably, the surfactant A is selected from alkyl aryl polyether sulfate; more preferably, lauryl polyethylene glycol sulfate. As a preferred technical solution, the preparation method of the modified rubber latex is to add the modified rubber solution to a solution obtained by mixing the surfactant A and water, homogenize and emulsify, and then remove the solvent to obtain a modified rubber latex with a total solid content of 10-60wt%.

[0037] Preferably, the homogenization emulsification conditions include: a rotation speed of 10000-30000 rpm, a temperature of 50-80° C., and a time of 5-25 min.

[0038] Preferably, the method of removing the solvent is vacuum distillation, and the conditions of the vacuum distillation include: a pressure of 20 to 40 kPa and a temperature of 50 to 60°C.

[0039] As a preferred technical solution, the total solid content of the modified rubber latex is 20-50wt%, preferably 30-45wt%.

[0040] The modified rubber latex provided by the invention is modified by using a modifier to modify chlorosulfonated polyethylene, especially by using any one of anhydrous ethanol, anhydrous methanol, polyethylene glycol monomethyl ether, ethanolamine, maleimide, hydroxyethyl acrylate, 2-bromoethanol and 3-hydroxypropionitrile to modify chlorosulfonated polyethylene with a chlorine content of 30-40wt%, a sulfur content of 0.8-2.0% and a Mooney viscosity (ML(1+4)@100°C) of 45-100, so that the bonding performance of an aqueous adhesive composition containing the modified rubber latex between metal and elastomer is significantly improved.

[0041] Another aspect of the present invention provides a water-based adhesive composition, which comprises at least the following components by mass percentage: 4.8-14.4% of nitroso, 2-10% of modified rubber latex, and the balance of pure water.

[0042] The aqueous adhesive composition is characterized in that it comprises at least the following components by mass percentage: 40-60% of mother liquor, 2-10% of modified rubber latex, 1-5% of halogenated natural rubber latex, and the balance of pure water; the raw materials for preparing the mother liquor, by mass percentage, include at least 12-24% of nitroso compounds, 5-15% of adhesion promoter, 8-15% of acid binding agent, 3-18% of carbon black, 1-8% of dispersing aid, and the balance of pure water.

[0043] Preferably, the raw materials for preparing the mother solution include, by mass percentage, at least 20-22% of nitroso compounds, 10-12% of adhesion promoters, 10-14% of acid binding agents, 5-14% of carbon black, 5% of dispersing aids, and the balance of pure water.

[0044] Preferably, the acid binding agent is selected from at least one of metal oxides, metal phosphates or lead salts, preferably metal oxides or metal phosphates.

[0045] Preferably, the metal oxide is selected from at least one of the oxides of zinc, cadmium, magnesium, lead and calcium, preferably zinc oxide.

[0046] Preferably, the metal phosphate is selected from at least one of zinc, magnesium, lead and calcium phosphates, preferably zinc phosphate.

[0047] Preferably, the lead salt is selected from at least one of dibasic lead phthalate, ternary lead maleate monohydrate, tetrabasic lead fumarate, dibasic lead phosphite, and basic lead carbonate.

[0048] As a preferred technical solution, the adhesion promoter at least includes a maleimide compound.

[0049] Preferably, the maleimide compound is an aromatic polymaleimide compound, preferably an aromatic polymaleimide having 2 to 200 aromatic nuclei.

[0050] Preferably, the aromatic polymaleimide has a structure shown in formula (4):

[0051] Formula (4): Here, X is 0-90, preferably X is 0-25.

[0052] Aromatic polymaleimide sold by different companies has different trade names, for example, BMI-20-M and BMI-S aromatic polymaleimide sold by Mitsu: Toatsu Fine Chemicals, Incorporated. In the present invention, a chemical additive (heat-resistant crosslinking agent-PAPI) of Otsuka Chemical Management Co., Ltd. is used.

[0053] As a preferred technical solution, the nitroso compounds are selected from nitroso compounds or nitroso compound precursors.

[0054] As a preferred technical solution, the nitroso compound is an aromatic compound containing at least two nitroso groups directly connected to non-adjacent ring carbon atoms.

[0055] Preferably, the nitroso compound is an aromatic compound having 1 to 3 aromatic nuclei (including fused aromatic nuclei), 2 to 6 nitroso groups directly connected to non-adjacent nuclear carbon atoms, and the nuclear hydrogen atoms on the aromatic nucleus can be substituted by alkyl, alkoxy, cycloalkyl, aryl, aralkyl, alkaryl, aromatic amine, aromatic nitroso, amino, or halogen.

[0056] Preferably, the nitroso compound is a dinitroso aromatic compound, preferably at least one of m-dinitrosobenzene, p-dinitrosobenzene, m-dinitrosonaphthalene, p-dinitrosonaphthalene, 2,5-dinitroso-p-cymene, 2-methyl-1,4-dinitrosobenzene, 2-methyl-5-chloro-1,4-dinitrosobenzene, 2-fluoro-1,4-dinitrosobenzene, 2-methoxy-1,3-dinitrosobenzene, 5-chloro-1,3-dinitrosobenzene, 2-benzyl-1,4-dinitrosobenzene and 2-cyclohexyl-1,4-dinitrosobenzene.

[0057] Preferably, the nitroso compound includes m-dinitrosobenzene and p-dinitrosobenzene, and the mass ratio of m-dinitrosobenzene to p-dinitrosobenzene is (0.5-2):1, preferably 1:1.

[0058] As a preferred technical solution, the nitroso compound precursor is any compound that can be converted into a nitroso compound by oxidation at 140-200°C.

[0059] Preferably, the nitroso compound precursor is a derivative of a quinone compound, preferably at least one of quinone dioxime, dibenzoquinone dioxime, 1,2,4,5-tetrachlorobenzoquinone, 2-methyl-1,4-benzoquinone dioxime, 1,4-benzoquinone dioxime, 1,2-benzoquinone dioxime and 2,6-benzoquinone dioxime.

[0060] As a preferred technical solution, the raw materials for preparing the halogenated natural rubber emulsion include, by weight, at least: 100-150 parts of chlorinated natural rubber, 200-350 parts of xylene, 5-30 parts of surfactant B, and 400-600 parts of water.

[0061] Preferably, the weight average molecular weight of the chlorinated natural rubber is 100,000 to 500,000, and the chlorine content is 50 to 70 wt%, more preferably 60 to 70 wt%.

[0062] The surfactant B is selected from at least one of carboxylates, acyl derivatives of sarcosine, sulfates, sulfated natural oil esters, alkyl aryl polyether sulfates, alkali metal alkyl sulfates, ethoxylated aryl sulfonates, alkyl aryl polyacyl sulfonates, isopropylbenzene sulfonates, sulfosuccinates, phosphates, ethoxylated (ethylene oxide) derivatives, alcohols, ethylene oxide / propylene oxide block copolymers, stearates, dehydration products of sorbitol, amines, lauric acid and isopropenyl halides.

[0063] Carboxylates that may be cited include: fatty acid soaps derived from lauric acid, stearic acid and oleic acid; acyl derivatives of sarcosine include: methylglycine; sulfates include: sodium lauryl sulfate; sulfated natural oil esters include: Turkey red oil; phosphates include: short-chain fatty alcohol partial esters of complex phosphates and orthophosphates of polyethoxylated fatty alcohols; stearic acid esters include: glycerol monostearate; dehydration products of sorbitol include: dehydrated sorbitan monostearate and polyethylene oxide dehydrated sorbitan monolaurate.

[0064] Preferably, the surfactant B is selected from alkyl aryl polyether sulfates; more preferably, dodecylphenol polyoxyethylene ether sulfonate.

[0065] Preferably, the preparation method of the halogenated natural rubber emulsion is: after stirring and mixing chlorinated natural rubber and xylene, add them to a solution of surfactant B and water, after homogenizing and emulsifying, remove the solvent to obtain a halogenated natural rubber emulsion with a total solid content of 10-60wt%.

[0066] Preferably, the preparation method of the halogenated natural rubber emulsion is: chlorinated natural rubber and xylene are stirred and mixed at 60-85°C for 4-6h, and then added to a solution obtained by mixing surfactant B and water; homogenizing and emulsifying for 5-25min with a homogenizer at a speed of 10000-30000rpm and a temperature of 50-80°C to obtain an emulsion; the emulsion is heated to 50-60°C under a reduced pressure of 20-40kPa to remove the solvent, and a halogenated natural rubber emulsion with a total solid content of 10-60wt% is obtained.

[0067] Preferably, the total solid content of the halogenated natural rubber emulsion is 20-50 wt %, preferably 30-45 wt %.

[0068] As a preferred technical solution, the dispersing aid is selected from at least one of sodium lignin sulfonate, calcium lignin sulfonate, alkaline lignin, and polycarboxylates, preferably sodium lignin sulfonate.

[0069] As a preferred technical solution, the preparation method of the water-based adhesive composition is: stirring and mixing the raw materials of the water-based adhesive composition to obtain the water-based adhesive composition.

[0070] Preferably, the preparation method of the water-based adhesive composition is: mixing and grinding nitroso compounds, acid binders, adhesion promoters, carbon black, dispersing aids, and pure water to a fineness of less than 10 μm to obtain a mother liquor; and stirring and mixing the mother liquor, modified rubber latex, halogenated natural rubber latex, and pure water to obtain the water-based adhesive composition.

[0071] Preferably, the grinding instruments include: ball mill, sand mill, ceramic bead mill, steel bead mill, high-speed medium mill.

[0072] Preferably, the stirring and mixing speed is 60-100 r / min.

[0073] Preferably, the stirring and mixing time is 10-60 min, preferably 20-40 min.

[0074] Preferably, the viscosity of the aqueous adhesive composition (25±1° C., rotational viscometer, 1# rotor 90 rpm) is 10 to 200 cps.

[0075] Preferably, the solid content of the aqueous adhesive composition is 10-50 wt %, preferably 14-28 wt %.

[0076] The present invention constructs a modified rubber latex-nitroso compound-adhesion promoter system, and in particular controls the addition amount of each raw material in the mother solution, so that the provided water-based adhesive composition still exhibits excellent bonding performance in initial bonding, baking resistance, high temperature fluid resistance and corrosive environment, and also still has good bonding performance in a high temperature environment.

[0077] The third aspect of the present invention provides an elastomer composite material, which comprises at least a substrate layer, a primer layer, a water-based adhesive layer, and an elastomer layer from bottom to top.

[0078] As a preferred technical solution, the material of the substrate layer is metal.

[0079] As a preferred technical solution, the material of the elastomer layer is NR55, NR70, NBR, SBR, EPDM (Taicang Guanlian Rubber) or three elastomers (WDK1, WDK2, WDK3) specified in the German Rubber Enterprise Association WDK (Wirtschaftsverband der DeutschenIKautschukindustrie).

[0080] As a preferred technical solution, the preparation method of the elastomer composite material includes:

[0081] The substrate layer is sandblasted or polished and then preheated to 50-100°C to obtain a pretreated substrate layer; a water-based primer is applied on the surface of the pretreated substrate layer to form a primer layer with an average thickness of 5-15 μm; a water-based adhesive composition is applied on the surface of the primer layer preheated to 50-100°C to form a 10-35 μm water-based adhesive layer, and rubber is molded, injection-pressed, and injection-molded onto the water-based adhesive layer at 140-180°C to obtain an elastomer composite material.

[0082] Preferably, the preparation method of the elastomer composite material comprises:

[0083] The substrate layer is sandblasted or polished and then preheated to 60-90°C to obtain a pretreated substrate layer; a water-based primer is applied on the surface of the pretreated substrate layer to form a primer layer with an average thickness of 7.5-12.5 μm; a water-based adhesive composition is applied on the surface of the primer layer preheated to 60-90°C to form a 15-25 μm water-based adhesive layer, and rubber is molded, injection-molded, and injection-molded onto the water-based adhesive layer at 150-170°C to obtain an elastomer composite material.

[0084] Preferably, the coating method is selected from one of spraying, dipping, brushing, smearing, dipping and roller coating, preferably spraying, brushing or dipping.

[0085] When applied by brushing or dipping, an aqueous adhesive composition with a solid content of 25±3wt% can achieve the best effect; when applied by spraying, an aqueous adhesive composition with a solid content of 17±3wt% can achieve the best effect.

[0086] The water-based adhesive composition provided by the present invention optimizes the combination of various raw materials in the system. When used for bonding metal substrates and elastomers, the bonding performance is basically the same as that of solvent-based adhesives, and at the same time meets the bonding requirements for various elastomers, and can be applied in a wider range.

[0087] The water-based adhesive composition provided by the present invention can meet the application requirements of rubber composite parts vulcanized by a semi-effective vulcanization system and rubber composite parts vulcanized by an effective vulcanization system in the automotive NVH field, and products bonded by the water-based adhesive composition can be stably stored for a long time in a high-temperature fluid and corrosive environment.

[0088] The water-based adhesive composition provided by the present invention meets the VOC requirements, does not contain chlorine-containing solvents such as dichloromethane, chloroform, chlorobenzene, etc., and the adhesive composition itself can be stably stored for more than 6 months, thus better meeting the practical application requirements.

[0089] Beneficial Effects

[0090] 1. The present invention provides a modified rubber latex. The aqueous adhesive composition prepared by using the modified rubber latex can effectively meet the bonding application requirements between metals and elastomers. The product is environmentally friendly and has excellent stability, and has extremely high market application and promotion value.

[0091] 2. The modified rubber latex provided by the present invention is modified by using a modifier to modify chlorosulfonated polyethylene, especially using any one of anhydrous ethanol, anhydrous methanol, polyethylene glycol monomethyl ether, ethanolamine, maleimide, hydroxyethyl acrylate, 2-bromoethanol, and 3-hydroxypropionitrile to modify chlorosulfonated polyethylene with a chlorine content of 30 to 40wt%, a sulfur content of 0.8 to 2.0%, and a Mooney viscosity (ML(1+4)@100°C) of 45-100, so that the bonding performance of an aqueous adhesive composition containing the modified rubber latex between metal and elastomer is significantly improved.

[0092] 3. The present invention constructs a modified rubber latex-nitroso compound-adhesion promoter system, especially controls the addition amount of each raw material in the mother liquor, so that the provided water-based adhesive composition still exhibits excellent bonding properties in initial bonding, baking resistance, high temperature fluid resistance and corrosive environment, and also has good bonding properties in high temperature environment.

[0093] 4. The water-based adhesive composition provided by the present invention optimizes the combination of various raw materials in the system. When used for bonding metal substrates and elastomers, the bonding performance is basically the same as that of solvent-based adhesives, while meeting the bonding requirements for a variety of elastomers and having a wider range of applications.

[0094] 5. The water-based adhesive composition provided by the present invention meets the VOC requirements and does not contain chlorine-containing solvents such as dichloromethane, chloroform, chlorobenzene, etc., and the adhesive composition itself can be stably stored for more than 6 months, better meeting the actual application requirements.

[0095] 6. In addition to being used in combination with a primer, the water-based adhesive composition provided by the present invention can also be used for bonding various substrates and various elastomers by single coating. Its performance is better than that of commercially available products, and its application scenarios are further broadened. DETAILED DESCRIPTION

[0096] Examples 1-17

[0097] Embodiments 1-17 of the present invention provide a modified rubber latex, and the formula is shown in Table 1 by mass percentage.

[0098] Table 1

[0099]

[0100]

[0101] In Table 1, surfactant A is ammonium dodecanol polyethylene glycol sulfate; the raw materials for preparing modified rubber solution 1-15, by mass percentage, are shown in Table 2. The preparation method of modified rubber solution 1-15 is as follows: add halogenated elastomer and solvent into a container, stir at 80°C for 5 hours, cool to 75°C, add modifier, and react at constant temperature for 5 hours to obtain modified rubber solution 1-15.

[0102] Table 2

[0103]

[0104]

[0105] In Table 2, “\” indicates that the addition amount of the corresponding raw material is 0. The grades of chlorosulfonated polyethylene and related performance parameters are shown in Table 3.

[0106] Table 3

[0107]

[0108] The preparation method of the modified rubber latex 1-17 is as follows: adding the modified rubber solution to a solution obtained by mixing surfactant A and water, homogenizing and emulsifying, and removing the solvent to obtain a modified rubber latex with a total solid content of 35 wt%.

[0109] The homogenization emulsification conditions include: a rotation speed of 20,000 rpm, a temperature of 65° C., and a time of 18 min.

[0110] The method of removing the solvent is vacuum distillation, and the conditions of the vacuum distillation include: pressure of 30 kPa and temperature of 55°C.

[0111] Application Examples 1-9

[0112] Application Examples 1-9 of the present invention provide a water-based adhesive composition, and the formula is shown in Table 4 in terms of mass percentage.

[0113] Table 4

[0114]

[0115] In Table 4, “\” indicates that the addition amount of the corresponding raw material is 0. The formulas of mother solutions A and B, in terms of mass percentage, are shown in Table 7.

[0116] Application Comparative Examples 1-12

[0117] The comparative application examples 1-12 of the present invention provide a water-based adhesive composition, and the formula is shown in Table 5 in terms of mass percentage.

[0118] Table 5

[0119]

[0120] In Table 5, “\” indicates that the addition amount of the corresponding raw material is 0. The formula of the mother solution AJ, in terms of mass percentage, is shown in Table 7.

[0121] Application Comparative Examples 13-23

[0122] The comparative application examples 13-23 of the present invention provide a water-based adhesive composition, and the formula is shown in Table 6 in terms of mass percentage.

[0123] Table 6

[0124]

[0125] In Table 6, “\” indicates that the addition amount of the corresponding raw material is 0. The formula of mother solution A, in terms of mass percentage, is shown in Table 7.

[0126] Table 7

[0127]

[0128] In Table 7, the preparation method of mother liquor AJ is as follows: in a horizontal grinder, at a grinding parameter of 3000 r / min, nitroso, acid binding agent, adhesion promoter, carbon black, dispersing aid, and pure water are added in the proportions shown in Table 7 and ground to a fineness of <10 μm to obtain mother liquor AJ.

[0129] The raw materials for preparing the halogenated natural rubber emulsion in Table 4-6, by weight, include: 120 parts of chlorinated natural rubber, 280 parts of xylene, 8 parts of surfactant B, and 500 parts of water.

[0130] The weight average molecular weight of the chlorinated natural rubber is 100,000 to 500,000, the chlorine content is 50 to 70 wt%, and the model is S170, sourced from Covestro Polymers China Ltd.

[0131] The surfactant B is ammonium dodecylphenol polyoxyethylene ether sulfonate.

[0132] The preparation method of the halogenated natural rubber emulsion is a common emulsion preparation method in the industry.

[0133] The preparation method of the water-based adhesive composition provided in Application Examples 1-9 and Comparative Examples 1-23 is as follows: the mother liquor, the modified rubber latex, the halogenated natural rubber latex and pure water are stirred and mixed to obtain the water-based adhesive composition. The stirring and mixing speed is 80 r / min. The stirring and mixing time is 30 min.

[0134] Performance Testing

[0135] 1. The water-based adhesive composition provided in Application Examples 1 and 2 is used for bonding metal iron and three elastomers (WDK1, WDK2, WDK3) specified in NR55 (Taicang Guanlian Rubber) and WDK (Wirtschaftsverband der DeutschenIKautschukindustrie) of the German Rubber Enterprise Association to obtain an elastomer composite material. The elastomer composite material is subjected to the following tests while hot or after cooling to room temperature (25°C). The test results are shown in Table 8. The preparation method of the elastomer composite material is as follows: sandblasting the iron-based substrate and preheating it to 75°C to obtain a pretreated substrate layer; spraying and coating a water-based primer (MEGUM TM W 9300) forms a primer layer with an average thickness of 10 μm on the surface of the pretreated substrate layer; applies the water-based adhesive compositions 1 and 2 on the surface of the primer layer preheated to 75° C. to form a 20 μm water-based adhesive layer; and molds, injection-presses, and injection-moldes the rubber onto the water-based adhesive layer at 165° C. to obtain an elastomer composite material.

[0136] 1. Initial Adhesion: Destroy the bonded part by peeling according to ASTM Test D429-Method B. After cooling the elastomer composite to room temperature, perform the peel test at a 45° peel angle. Test at room temperature at a speed of 0.8 cm per second. After the specimen fails, measure the percentage of rubber retained on the bond failure surface.

[0137] 2. Thermal peel test: The above-mentioned elastomer composite material is peeled off immediately after the bonding reaction is completed (peeling test is carried out at a peeling angle of 45° and at a speed of 0.8 cm per second at room temperature). Then, after the bonding fails, the rubber retention percentage on the bonding failure surface is measured.

[0138] 3. Boiling water resistance: Use a hand drill to drill a small hole on one side of the rubber, then use a piece of rope with a center to pull the elastomer away from the metal, and then use a razor blade to scratch the bonding line of the bonding interface to cause damage. Then soak the elastomer composite in 100°C boiling water. Place the elastomer composite in this environment, take it out after 1 hour, 5 hours, 12 hours, 24 hours, 48 ​​hours, and 72 hours, peel the rubber from the metal with pliers, and then test the rubber retention percentage on this part.

[0139] 4. High temperature resistance test: After the elastomer composite material is cooled to room temperature, it is placed in a 150°C blast oven for 15 minutes, and the bonded part is broken by peeling while hot according to ASTM Test D429-Method B. The peeling test is carried out at a peeling angle of 45°. The test is carried out at a speed of 0.8 cm per second at room temperature. After the specimen fails to bond, the rubber retention percentage on the bond failure surface is measured.

[0140] Table 8

[0141]

[0142]

[0143] The data in Table 8 represent the percent failure of the elastomer bulk. A high percent failure of the elastomer is desirable, indicating that the adhesive bond is stronger than the elastomer itself.

[0144] 5. Salt spray resistance: The elastomer is NR55, and the bonding part is polished on the edge with a grinding wheel. Then use stainless steel wire to pull the rubber away from the metal to expose the bonding area and expose the bonding line to the environment. Score the bonding line with a razor blade to cause rupture, then tie the part to the stainless steel wire and put it in a salt spray chamber. The environment in the room is 100% relative humidity, the temperature is 95°C, and there is 5% sodium chloride solution dissolved in the spray liquid, which is distributed throughout the room. This part is placed in this environment for 5 hours, 12 hours, 24 hours, 48 ​​hours, and 72 hours. After taking it out, use pliers to peel the elastomer from the metal, and then measure the percentage of residual elastomer on the part. See Table 9 for the test results.

[0145] Table 9

[0146]

[0147]

[0148] 6. Baking resistance: The elastomer is NR55. The elastomer composite is exposed to the pre-baking conditions shown in Table 10. It is pre-baked before the elastomer contacts the coated substrate (this can simulate whether the water-based adhesive composition retains sufficient activity to successfully bond the elastomer in the actual production process). After the elastomer composite is cooled to room temperature, its bonding performance is evaluated according to the initial bonding test method. Finally, the percentage of residual elastomer on the part is measured. The test results are shown in Table 10.

[0149] Table 10

[0150]

[0151] 2. The aqueous adhesive compositions of application examples 1-9 and comparative examples 13-18 were used to bond metal iron and NR55, NR70, NBR, SBR, EPDM (all purchased from Taicang Guanlian Rubber) to obtain an elastomeric composite material. The elastomeric composite material was tested for initial adhesion and boiling water resistance. The test results are shown in Table 11 and Table 12, respectively. The preparation method of the elastomeric composite material is: sandblasting the iron-based substrate and preheating it to 75°C to obtain a pretreated substrate layer; spraying and coating the water-based primer (MEGUM TM W 9300) forms a primer layer with an average thickness of 10 μm on the surface of the pretreated substrate layer; applies a water-based adhesive composition on the surface of the primer layer preheated to 75° C. to form a 20 μm water-based adhesive layer; and molds, injection-presses, and injection-moldes the rubber onto the water-based adhesive layer at 165° C. to obtain an elastomer composite material.

[0152] Table 11

[0153]

[0154] Table 12

[0155]

[0156]

[0157] 3. The aqueous adhesive composition provided in the application example and the comparative example is used for bonding between metal iron and NR55 (Taicang Guanlian Rubber) to obtain an elastomeric composite material. After the elastomeric composite material is cooled to room temperature (25°C), a pull-out initial adhesion test is performed (refer to ASTM D429-test method A), and the maximum peeling value from tensile peeling to rupture and the percentage of rubber rupture are used as the test results (see Table 13). The preparation method of the elastomeric composite material is as follows: a disc-shaped iron-based substrate with a diameter of 40 mm is sandblasted and preheated to 75°C to obtain a pretreated substrate layer; a water-based primer (MEGUM TM W 9300) forms a primer layer with an average thickness of 10 μm on the surface of the pretreated substrate layer; applies the water-based adhesive compositions 1 and 2 on the surface of the primer layer preheated to 75° C. to form a 20 μm water-based adhesive layer; and molds, injection-presses, and injection-moldes the rubber onto the water-based adhesive layer at 165° C. to obtain an elastomer composite material.

[0158] Table 13

[0159]

[0160]

[0161] 4. Thermal tear resistance: The test specimens bonded with the initial pull-out adhesion were placed in a 150°C blast oven for 15 minutes, then stretched and peeled while hot until they broke, and the maximum peel force value and the elastomer rupture percentage were recorded. The test results are shown in Table 14.

[0162] Table 14

[0163]

[0164]

[0165]

[0166] 5. The aqueous adhesive composition provided by Example 1, 2, 3, 6, 7, 8, 9 and Comparative Example 13, 14, 15 is used for bonding between the buffer and NR55 (Taicang Guanlian Rubber) to obtain an elastomeric composite material. After the elastomeric composite material is cooled to room temperature (25°C), the initial pull-out adhesion test of the buffer is performed (refer to ASTM D429-Test Method A), and the maximum peeling value from tensile peeling to rupture and the percentage of rubber rupture are used as the test results (see Table 15). The preparation method of the elastomeric composite material is: the buffer is sandblasted and preheated to 75°C to obtain a pretreated substrate layer; a water-based primer (MEGUM TM W 9300) forms a primer layer with an average thickness of 10 μm on the surface of the pretreated substrate layer; applies the water-based adhesive compositions 1 and 2 on the surface of the primer layer preheated to 75° C. to form a 20 μm water-based adhesive layer; and molds, injection-presses, and injection-moldes the rubber onto the water-based adhesive layer at 165° C. to obtain an elastomer composite material.

[0167] Table 15

[0168] Maximum peeling force (kN / m) Elastic body damage % Application Example 1 24.9 94 Application Example 2 24.8 95 Application Example 3 25 93 Application Example 6 25.3 87 Application Example 7 25.6 96 Application Example 8 25.1 90 Application Example 9 21.9 65 Application Comparative Example 13 20.7 60 Application Comparative Example 14 19.1 45 Application Comparative Example 15 20.5 60

[0169] 6. Thermal tear resistance of the buffer: The test specimens of the buffer with initial pull-out adhesion were placed in a 150°C blast oven for 15 minutes, then stretched and peeled while hot until they broke, and the maximum peel force value and the elastomer rupture percentage were recorded. The test results are shown in Table 16.

[0170] Table 16

[0171] Maximum peeling force (kN / m) Elastic body damage % Application Example 1 16.3 91 Application Example 2 16.4 94 Application Example 3 15.3 90 Application Example 6 15.4 88 Application Example 7 14.9 82 Application Example 8 16.8 93 Application Example 9 15.3 86 Application Comparative Example 13 8.9 10 Application Comparative Example 14 10.2 25 Application Comparative Example 15 10.5 30

[0172] VII. Buffer resistance to boiling water: The buffer is pulled and initially bonded to the test sample, which is placed in a mold and stretched by 30% and maintained at 30% elongation during the entire test process, and then placed in a boiling water solution for 250 hours. The test sample is then stretched and peeled until it breaks and the maximum peel value and rubber damage percentage are recorded. The test results are shown in Table 17.

[0173] Table 17

[0174] Maximum peeling force (kN / m) Elastic body damage % Application Example 1 25.9 95 Application Example 2 26.0 98 Application Example 3 25.5 98 Application Example 6 24.9 89 Application Example 7 25.1 92 Application Example 8 24.2 90 Application Example 9 23.2 80 Application Comparative Example 13 20.4 25 Application Comparative Example 14 22.3 56 Application Comparative Example 15 21.9 49

[0175] 8. Buffer resistance to ethylene glycol: The buffer pull-out initial adhesion bonded test sample is placed in a mold and stretched by 30% and maintained at 30% elongation during the entire test process, and then the test sample is placed in a 90°C 5wt% ethylene glycol aqueous solution for 250 hours. After the test, the test sample is taken out and cooled to room temperature, and then the test sample is stretched and peeled until it breaks and the maximum peel value and rubber damage percentage are recorded. The test results are shown in Table 18.

[0176] Table 18

[0177] Maximum peeling force (kN / m) Elastic body damage % Application Example 1 24.9 93 Application Example 2 25.1 95 Application Example 3 23.4 90 Application Example 6 25.3 85 Application Example 7 25.6 97 Application Example 8 25.1 89 Application Example 9 23.9 77 Application Comparative Example 13 20.1 29 Application Comparative Example 14 22.3 54 Application Comparative Example 15 21.9 50

[0178] IX. Single coating bonding of different substrates: The water-based adhesive compositions provided in Examples 1 and 2 and Comparative Examples 4 to 6 and commercial water-based adhesives ( 8212) is used for bonding metal iron sheets, metal zinc sheets, white nylon sheets, black nylon sheets, galvanized nickel sheets, 304 stainless steel sheets and NR55 (Taicang Guanlian Rubber) to obtain an elastomeric composite material. After the elastomeric composite material is cooled to room temperature (25°C), the following tests are carried out. The test results are shown in Table 19. The preparation method of the elastomeric composite material is as follows: the metal iron sheet, white nylon and black nylon substrates are directly used after polishing; the metal zinc sheet, galvanized nickel sheet and 304 stainless steel sheet are all cleaned by a solvent method: the bonding surface is wiped with a cotton ball dipped in ethyl acetate and MIBK solution, and then dried at room temperature. The above-treated substrate is preheated to 75°C to obtain a pretreated substrate, and then directly coated with the water-based adhesive composition Application Examples 1, 2 and Comparative Examples 4 to 6 and commercial water-based adhesives ( 8212) A 15-20 μm water-based adhesive layer is formed on the surface of a substrate preheated to 75°C, and the rubber is molded, injection-molded, or injection-molded onto the water-based adhesive layer at 165°C to obtain an elastomer composite material.

[0179] Initial Adhesion: The bonded portion was broken by peeling according to ASTM Test D429-Method B. After the elastomer composite was cooled to room temperature, the peel test was performed at a peel angle of 45°. The test was performed at a speed of 0.8 cm per second at room temperature. After the specimen failed, the exposed percentage of the substrate and the elastomer failure percentage on the bond failure surface were measured. The test results are shown in Table 19.

[0180] Table 19

[0181]

[0182]

[0183] The data in Table 19 represent the percentage of substrate exposure and the percentage of elastomer bulk failure, with low percentage of substrate exposure and high percentage of elastomer failure being ideal.

[0184] 10. Single coating bonding of different rubbers: The water-based adhesive compositions provided in Examples 1 and 2 and Comparative Examples 4 to 6 and commercial water-based adhesives ( 8212) is used for bonding white nylon sheets and NR55 (Taicang Guanlian Rubber) and three elastomers (WDK1, WDK2, WDK3) specified in the German Rubber Enterprise Association WDK (Wirtschaftsverband der Deutschen IKautschukindustrie) to obtain an elastomer composite material. After the elastomer composite material is cooled to room temperature (25°C), the following tests are carried out. The test results are shown in Table 20. The preparation method of the elastomer composite material is: the white nylon sheet is directly used after polishing. The above-mentioned treated substrate is preheated to 75°C to obtain a pretreated substrate, and then directly coated with the water-based adhesive composition Application Examples 1, 2 and Comparative Examples 4 to 6 and commercial water-based adhesives ( 8212) A 15-20 μm water-based adhesive layer is formed on the surface of a substrate preheated to 75°C, and the rubber is molded, injection-molded, or injection-molded onto the water-based adhesive layer at 165°C to obtain an elastomer composite material.

[0185] Initial Adhesion: The bonded portion was broken by peeling according to ASTM Test D429-Method B. After the elastomer composite was cooled to room temperature, the peel test was performed at a peel angle of 45°. The test was performed at a speed of 0.8 cm per second at room temperature. After the specimen failed, the exposed percentage of the substrate and the elastomer failure percentage on the bond failure surface were measured. The test results are shown in Table 20.

[0186] Table 20

[0187]

[0188] The data in Table 20 represent the percentage of substrate exposure and the percentage of elastomer bulk failure, with low percentage of substrate exposure and high percentage of elastomer failure being ideal.

Claims

1. A modified rubber latex, characterized in that: The raw materials for its preparation include at least 10-70% of modified rubber solution, 0.01-5% of surfactant and the balance of water, in terms of mass percentage, wherein the modified rubber solution is prepared by modifying the halogenated elastomer with a modifier.

2. The modified rubber emulsion according to claim 1, characterized in that The raw materials for preparing the modified rubber solution include at least the following components by mass percentage: 10-20% of halogenated elastomer, 0.5-2% of modifier, and the balance of solvent.

3. The modified rubber emulsion according to claim 2, characterized in that The halogenated elastomer is selected from at least one of halogenated natural rubber and halogen-containing synthetic rubber.

4. The modified rubber emulsion according to claim 3, characterized in that The halogen-containing synthetic rubber includes at least one of polychloroprene, halogenated polychloroprene, halogenated polybutadiene, hexachloropentadiene, butadiene-halogenated cyclic conjugated diene adducts, halogenated butadiene styrene copolymers, halogenated ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene terpolymers, halogenated polyethylene, halogenated sulfonated polyolefins, halogenated poly (2,3-dichloro-1,3-butadiene), copolymers of α-halogenated acrylonitrile and 2,3-dichloro-1,3-butadiene, and halogenated polyvinyl chloride.

5. The modified rubber emulsion according to claim 2, characterized in that: The modifier is selected from at least one of the structures represented by formula (1) to formula (4), Formula (1): R-OH, wherein R represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 n-valent straight-chain or branched alkynyl, C6~C 40 n-valent aromatic group; any one of -H and -CH3 in R can be replaced by an oxygen atom, a halogen atom, a cyano group or a methoxy group; Formula (2): Where R1 represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 n-valent straight-chain or branched alkynyl, C6~C 40 an n-valent aromatic group, R2 represents a methyl group or a hydrogen atom; any -H in R1 may be replaced by a halogen atom, any -CH3 in R1 may be replaced by a methoxy group or a cyano group, and any -CH2- in R1 may be replaced by an oxygen atom or a sulfur atom; Formula (3): Formula (4): Where R represents C1~C 40 A straight or branched n-valent alkyl group, C2~C 30 n-valent straight-chain or branched alkenyl, C3~C 30 an n-valent straight-chain or branched alkynyl group or a halogen atom; any -H or -CH3 in R may be substituted by an oxygen atom, a halogen atom, a cyano group or a methoxy group.

6. A water-based adhesive composition, characterized in that: The modified rubber latex according to any one of claims 1 to 5 comprises at least the following components by mass percentage: 4.8-14.4% of nitroso, 2-10% of modified rubber latex, and the balance of pure water.

7. The aqueous adhesive composition according to claim 6, characterized in that: The invention comprises at least the following components by mass percentage: 40-60% of mother liquor, 2-10% of modified rubber latex, 1-5% of halogenated natural rubber latex, and the balance of pure water; the raw materials for preparing the mother liquor comprise at least 12-24% of nitroso compounds by mass percentage, 5-15% of adhesion promoter, 8-15% of acid binding agent, 3-18% of carbon black, 1-8% of dispersing aid, and the balance of pure water.

8. The aqueous adhesive composition according to claim 6, characterized in that: The acid binding agent is selected from metal oxides and metal phosphates. The metal oxide is preferably zinc oxide, and the metal phosphate is preferably zinc phosphate.

9. The aqueous adhesive composition according to claim 6, characterized in that: The adhesion promoter includes at least a maleimide compound, and the maleimide compound is preferably an aromatic polymaleimide having an aromatic core.

10. The aqueous adhesive composition according to claim 6, characterized in that: The dispersing aid is selected from sodium lignin sulfonate, calcium lignin sulfonate, alkaline lignin, and polycarboxylates, preferably sodium lignin sulfonate.

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