CN113913024B - Addition type liquid silicone rubber, vulcanized rubber and preparation method thereof - Google Patents
Addition type liquid silicone rubber, vulcanized rubber and preparation method thereof Download PDFInfo
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Abstract
The invention relates to an addition type liquid silicone rubber, vulcanized rubber thereof and a preparation method thereof. Due to the addition of the halogenated aniline, the positive vulcanization time of the liquid silicone rubber is obviously shortened, and meanwhile, the hardness, tensile strength, elongation at break and other physical and mechanical properties of the obtained vulcanized rubber are basically kept unchanged, or the vulcanization temperature can be reduced or the use amount of a platinum catalyst can be reduced under the condition of keeping the positive vulcanization time unchanged. Therefore, the liquid silicone rubber prepared by the invention has the advantages of high vulcanization speed, simple and convenient preparation method, low-cost and easily-obtained raw materials, energy conservation, production efficiency improvement and production cost reduction.
Description
Technical Field
The invention belongs to the technical field of rubber, and particularly relates to an addition type liquid silicone rubber, vulcanized rubber thereof and preparation methods thereof.
Background
The addition type liquid silicone rubber is nontoxic, odorless, good in transparency and good in fluidity, can be injected, poured or molded, and is widely used in industry, medical treatment and articles for daily use at present. The addition type liquid silicone rubber not only can be singly formed into silicone rubber products in the form of vulcanized rubber, but also can be compounded with materials such as metal, glass, ceramic, plastic and the like to form a compound. When the addition type liquid silicone rubber is formed by heat vulcanization compounding with a plastic having a low heat distortion temperature such as polyethylene, polypropylene, polystyrene, polyvinyl chloride or ABS, it is necessary to control the vulcanization temperature to a temperature lower than the heat distortion temperature of the plastic. Even engineering plastics with high softening temperature such as polymethyl methacrylate, polycarbonate, polyamide and polyoxymethylene are subject to thermal deformation in the range of 100-150 ℃, so that when these plastics and liquid silicone rubber are subjected to heat vulcanization composite molding, the heat vulcanization temperature must be lowered to ensure that the plastics are not subject to thermal deformation during heat vulcanization composite molding. For the same compound to be vulcanized, the reduction of the vulcanization temperature leads to an increase of the positive vulcanization time and a reduction of the production efficiency.
In addition type liquid silicone rubber, increasing the vinyl content of vinyl silicone oil, increasing the amount of crosslinking agent (hydrogen-containing silicone oil) or catalyst (such as platinum complex) may increase the vulcanization rate of the addition type silicone rubber, but is likely to significantly affect the physical properties of the rubber compound such as hardness, tensile strength, elongation at break and tear strength, and may even make the rubber compound hard, easily broken and brittle. Therefore, it is significant to find an additive which can improve the vulcanization rate of the liquid silicone rubber, shorten the vulcanization time and maintain the physical properties of the vulcanized rubber of the liquid silicone rubber.
Liu Jingtao and the like, and the results show that: the activity of chloroplatinic acid-divinyl tetramethyl disiloxane is greater than that of chloroplatinic acid-isopropanol, and the silicone rubber vulcanization time is shortened (Liu Jingtao, mo Lipeng, dong Lijie, liu Liping, platinum catalyzed addition liquid vinyl silicone rubber properties, elastomer, 2008,18 (4), p 25-28). Lei Weihua et al studied the effect of polyvinyl cyclosiloxane and 3, 5-dimethyl-1-hexyn-3-ol on the crosslinking curing effect of liquid addition type silicone rubber at moderate temperature of 60 ℃, and as a result, showed that polyvinyl cyclosiloxane as a crosslinking inhibitor was characterized by short inhibition time and rapid curing (Lei Weihua, zhu Jingzhi, yu Fengmei, geng Cheng, the effect of polyvinyl cyclosiloxane, dimethyl hexynol on the crosslinking curing of liquid addition type silicone rubber, chemical new materials, 2020 (1), p 173-176). Yin Jin and the like research on the influence factors of the vulcanization rate of the injection molding liquid silicone rubber, and the result shows that the positive vulcanization time of the liquid silicone rubber is shortened along with the increase of the dosage of the platinum catalyst; when the inhibitor amount was reduced from 0.89 parts to 0.56 parts, the time for orthovulcanization of the liquid silicone rubber was shortened from 105s to 89s (Yin Jin, port, sun Jiang, zhou Lei, wang Yingming, zhou Ling, xiaoyouling Gao Yangong, investigation of the influence factor of vulcanization rate of injection molded liquid silicone rubber, silicone material, 2021, 35 (1), p 47-49).
U.S. Pat. No. 47741111 (1987) "Heat-curable Silicone Compositions Comprising Fumarate Cure-control Additive and Use thereof" teaches that the addition of a fumarate to a silicone composition allows an addition type silicone coating to remain liquid at a temperature below 40 ℃ for several hours, but to cure rapidly within 90 seconds when heated to 82 ℃. Us 5017654 (1989) "Thermosetting Organosiloxane Composition" proposes the addition of microencapsulated platinum-containing hydrosilation catalysts and conventional inhibitors of such catalysts to addition-type silicone materials to give a thermoset silicone material that has excellent storage stability near room temperature but cures rapidly at high temperatures. U.S. Pat. No. 5,5254656 (1992) "Curable Organosiloxane Compositions Containing Organotitanate/Microencapsulated Platinum Co-catalysts" discloses that in the simultaneous presence of an organotitanium compound and a microencapsulated platinum catalyst, not only can the thermal stability of the resulting elastomer be increased, but also the cure rate of the silicone rubber is surprisingly increased. European patent EP0654497A1 (1994) "Cure control of silicone rubber compositions" discloses the preparation of addition type silicone rubbers which are stable and resistant to premature gelation at room temperature but which can be rapidly vulcanized under heating by the addition of triazines or sulfides. U.S. Pat. No. 6,627,658 (1999) "Addition-curable Silicone Rubber Composition" provides a compound having good storage stability and rapid vulcanization characteristics by adding an acrylate compound or a methacrylate compound having a melting point of 40℃or higher to an Addition type silicone rubber. U.S. patent 6573128 (2001) "Low Temperature, fast Curing Silicone Compositions" discloses a Low Temperature fast cure silicone composition containing a rhodium-based catalyst. Japanese patent laid-open No. 2002-12768, "company コ" discloses an addition type silicone rubber composition containing a microencapsulated platinum catalyst and a hydroxy acid, which has excellent storage stability at room temperature and can be rapidly cured when heated. U.S. Pat. No. 6,777,031 (2002) "Addition-crosslinking Silicone Rubber Mixtures" discloses the use of cis-dichlorobis (styrene) platinum (II) as a catalyst in Addition-type silicone rubbers, which simultaneously give silicone rubbers with high reactivity and good adhesion properties. U.S. patent applications 20050080216 and 20060205908"Fast Curing Liquid Silicone Rubbers" provide a fast curing one or two part silicone rubber by adding appropriate amounts of both a silicon hydride and an organic peroxide. Japanese patent laid-open No. 2016-151010A, "additional curable type コ composition" discloses an addition type silicone composition having rapid vulcanization by using an organopolysiloxane having a specific structure. WO2017170474A1 and us patent 10364353 (2018) "Silicone Rubber Composition and Silicone Rubber Crosslinked Body" disclose the use of a microcapsule-type catalyst composed of resin particles and a crosslinking catalyst encapsulated in the resin particles in addition-type silicone rubber to obtain excellent storage stability and crosslinking reactivity.
Chinese patent application 201510377326, "a novel platinum vulcanizing agent and a preparation process thereof," refers to a catalyst prepared by using methyl vinyl silicone rubber as a carrier of a tetramethyl divinyl disiloxane platinum complex, and the vulcanizing speed can be 1/3-1/2 faster than that of the existing platinum vulcanizing agent. Chinese patent application 201810547459.1 "A liquid silicone rubber with rapid thermal curing and its preparation method" adds an organic titanium compound (such as tetrabutyl titanate) into the liquid silicone rubber, so that the liquid silicone rubber composition can be rapidly cured at 170 ℃ for 1-2 minutes, and the sufficient adhesion between the silicone rubber and the fiber can be obtained in a short time. The Chinese patent application 201911194922.X 'a UV curing non-modified organic silicon material for LED packaging and a preparation method thereof' discloses that the organic silicon material is subjected to catalytic hydrosilylation reaction under the irradiation of UV light through a platinum catalyst with a special structure, so that UV curing is realized on the premise of not modifying an organic group, the curing speed is high, the light transmittance is high, and the aging resistance is good.
U.S. Pat. No. 5569688, "heat-curable silicone rubber compositions" and Chinese patent No. 201811571139.6, "vulcanization method of addition type silicone rubber", provide a method for changing vulcanization characteristics of addition type silicone rubber by adding ammonia or a precursor of ammonia to addition type silicone rubber, by which vulcanization speed of addition type silicone rubber is increased, vulcanization temperature is lowered, vulcanization time is shortened, and production efficiency is improved. Although ammonia, ammonia water, carbonized ammonia water or liquid ammonia can improve the vulcanization rate of the addition type silicon rubber, the method has the problems of large smell, large volatility of ammonia and difficult control of the actual addition amount of the ammonia added into the rubber material, thereby possibly causing unstable vulcanization rate and mechanical property of the rubber material
It is known that addition type silicone rubbers including addition type liquid silicone rubbers have a great disadvantage in that, when they are brought into contact with an organic substance containing N, P, S or an ionic compound of a heavy metal such as Sn, pb, hg, bi, as and an alkynyl group-containing unsaturated organic substance, the platinum catalyst contained therein is liable to be poisoned and the silicone rubber cannot be vulcanized. See the relevant literature:
[1] tan Bien, zhang Lianzheng platinum catalyst research progress in the organosilicon industry [ J ], aerospace materials technology, 1999, 29 (3): 12-17.
[2] Lin Manhui, liu Dongcan, huang Suojuan. Investigation of anti-poisoning problem of addition type silicone rubber [ J ], silicone materials, 2001, l5 (1): 24-26.
[3] Tu Zhixiu, yang Yang, liu Anhua, wang Peng. Research progress of addition-reaction silicone rubber [ J ], rubber industry, 2006, 53 (4): 251-253.
The "catalytic mechanism" in the vulcanization of addition type silicone rubber is complicated, and there are various types of reactions "(see the above-mentioned document [3 ]), and therefore, the influence of various compounds on the vulcanization characteristics and the vulcanized rubber properties of addition type silicone rubber is difficult to be summarized.
Disclosure of Invention
The addition type liquid silicone rubber is an organosilicon material which takes polysiloxane containing hydrogen silicon bond (Si-H) as a cross-linking agent, and takes addition reaction with alkenyl through the hydrogen silicon bond under the existence of a platinum catalyst at room temperature or under heating, thereby realizing vulcanization (or cross-linking). The addition type liquid silicone rubber is the same as the condensation type liquid silicone rubber, and has single component and double component according to the packaging form of the product.
The purpose of the invention is that: the present invention provides a method for preparing an addition type liquid silicone rubber vulcanizate by adding a halogenated aniline to an addition type liquid silicone rubber to increase the vulcanization rate. Compared with the corresponding addition type liquid silicone rubber vulcanized rubber without adding the halogenated aniline, the physical and mechanical properties of the addition type liquid silicone rubber vulcanized rubber added with the halogenated aniline are basically maintained unchanged.
The technical scheme of the invention is as follows: an addition type liquid silicone rubber, its vulcanized rubber and their preparing process are disclosed. The addition type liquid silicone rubber contains 0.0025% -5.0% of halogenated aniline based on the weight of the addition type liquid silicone rubber. The addition type liquid silicone rubber is an elastomer material with a three-dimensional network structure, wherein the addition reaction of polysiloxane containing hydrogen silicon bonds and polysiloxane containing alkenyl groups is carried out by using the addition type liquid silicone rubber as a cross-linking agent under the action of a platinum catalyst. The proportions or contents of the various components in the invention are based on weight unless otherwise specified: the term "parts" refers to parts by weight; the percentages are weight percentages; ppm is weight ppm.
In the context of a specific embodiment of the present invention,
the halogenated aniline is added in the preparation process of the addition type liquid silicone rubber or before the vulcanization molding of the addition type liquid silicone rubber, thereby playing a role in improving the vulcanization rate of the addition type liquid silicone rubber.
The addition type liquid silicone rubber contains both an alkenyl group-containing polysiloxane and a hydrogen-containing silicon bond-containing polysiloxane. As an example, the additive liquid silicone rubber comprises the following raw materials in proportions: 100 parts of polysiloxane containing alkenyl, 2-30 parts of polysiloxane containing hydrogen silicon bond, 5-100 parts of white carbon black, 0.005-5 parts of platinum catalyst, 0.001-1 part of inhibitor and 0.05-5 parts of halogenated aniline, wherein the platinum catalyst is in the form of solution, paste or solid silicone rubber raw colloid or powder, and the mass concentration of platinum atoms is 100-10000ppm or the content of platinum atoms is 1% -100%.
During transportation and storage, addition type liquid silicone rubber is often divided into two parts, glue a and glue B. And (3) mixing the adhesive A and the adhesive B, and then performing vulcanization molding. The addition type liquid silicone rubber is a mixture formed by mixing an A rubber and a B rubber in a weight ratio of 10:1-1:10, wherein the A rubber contains polysiloxane containing alkenyl, white carbon black and platinum catalyst, the B rubber contains polysiloxane containing alkenyl, white carbon black and polysiloxane containing hydrogen silicon bond and inhibitor, and the A rubber and/or the B rubber contains halogenated aniline or the mixture of the A rubber and the B rubber contains halogenated aniline. That is, the halogenated aniline may be mixed only in the glue a, may be mixed only in the glue B, or may be mixed in both the glue a and the glue B, or the halogenated aniline may be added and mixed uniformly when or after the glue a and the glue B are mixed, to obtain a mixture of the glue a and the glue B containing the halogenated aniline. The mixture can be rapidly vulcanized at room temperature or at elevated temperature to give a vulcanized liquid addition type silicone rubber or an addition type liquid silicone rubber vulcanized rubber.
Preferably, the A and B gums are mixed in a 1:1 ratio.
In the addition type liquid silicone rubber, the polysiloxane containing alkenyl groups may be selected from one or more of a polysiloxane containing only alkenyl groups, and a polysiloxane containing both alkenyl groups. The viscosity of the polysiloxane containing alkenyl is 5000-100000cP, and the alkenyl content is 0.025% -2.5% respectively. The polysiloxane containing alkenyl is polysiloxane or silicone oil containing vinyl, allyl or propenyl. Vinyl silicone oils are preferred for cost reasons and the like to prepare addition type liquid silicone rubbers.
The polysiloxane containing hydrogen silicon bond or hydrogen silicone oil is a crosslinking agent of addition type liquid silicone rubber, reacts with alkenyl in the polysiloxane containing alkenyl under the action of a hydrosilylation catalyst to form Si-C bond to generate a crosslinking structure. The polysiloxane containing hydrogen-silicon bond is one or more of hydrogen-containing silicone oil, hydrogen-containing silicone resin or hydrogen-containing polysilsesquioxane, wherein the hydrogen-containing silicone oil is selected from silicone oil containing only terminal hydrogen groups, silicone oil containing only lateral hydrogen groups, silicone oil containing both terminal hydrogen groups and lateral hydrogen groups, and the hydrogen content of the hydrogen-containing silicone oil is 0.1-1.6%; the hydrogen-containing silicone resin is a polysiloxane polymer with a cross-linked structure, wherein the molecular chain of the polysiloxane polymer contains a plurality of hydrogen-silicon bonds; the hydrogen-containing silicon bond polysilsesquioxane is in a trapezoid, branch or cage structure, and each polysilsesquioxane molecule at least contains two hydrogen silicon bonds.
The inhibitor used in the present invention may be selected from one or two of methylbutynol, 1-ethynylcyclohexanol, 3, 5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-methyl-3-butyn 2-ol, 4-trimethylsilicon-3-butyn-2-ol, phenyl (trimethylbutynyloxy) silane, vinyl (trimethylbutynyloxy) silane, methyltri (cyclohexylynyloxy) silane, dimethyl butynyldioate, hexaallyl trimethamide, diallyl maleate, azobenzene-4, 4' -dicarboxylic acid dimethyl ester, N-phenyl-1, 2, 4-triazolin dione, N-methyl-1, 2, 4-triazolin dione, polydivinyl tetramethyl disiloxane, tetravinyl tetramethyl cyclosiloxane, tetramethyl divinyl disiloxane.
Platinum catalysts are the most commonly used hydrosilylation catalysts for addition type silicone rubber. The platinum catalyst of the present invention is selected from one or more of chloroplatinic acid, ammonium hexachloroplatinate, potassium chloroplatinite, potassium hexachloroplatinate, potassium trichloroammonium platinate, tetraamminoplatinate, cis-dichlorodiammineplatinum (II), tetraamminoplatinum (II), dinitroso diammineplatinum or sodium hexachloroplatinate, tetrakis (triphenylphosphine) platinum, platinum acetylacetonate, trifluoroacetylacetonate, platinum hexafluoroacetylacetonate or benzoylacetonate, alcohol-modified chelates of chloroplatinic acid, tetrahydrofuran-coordinated platinum chelates, acetylacetonate chelates of chloroplatinic acid, chloroplatinic acid-methylvinylsiloxane complexes, chloroplatinic acid-divinylbenzene tetrasiloxane complexes, chloroplatinic acid-tetramethyl tetravinylcyclosiloxane, hot melt polymer-coated platinum compounds described above, platinum powders, platinating powders, supported platinum catalysts, bimetallic catalysts containing platinum.
Alternatively, the platinum catalyst is added in the form of a solution, and the concentration of platinum atoms in the platinum catalyst solution is 500 to 10000ppm.
The hot melt polymer is cyclodextrin, acrylic resin, styrene resin or silicone resin.
The invention is characterized in that the halogenated aniline is introduced into the addition type liquid silicone rubber to improve the vulcanization speed of the addition type liquid silicone rubber. The halogenated anilines used include o-fluoroaniline, m-fluoroaniline, p-fluoroaniline, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline, m-bromoaniline and p-bromoaniline, and these halogenated anilines may be incorporated into the addition type liquid silicone rubber alone or two or more halogenated anilines may be incorporated into the addition type liquid silicone rubber at the same time.
It was found that among all the above-mentioned halogenated anilines, p-chloroaniline was more remarkable in improving the vulcanization rate of the addition type liquid silicone rubber, and at the same time, the effect of p-chloroaniline on the physical properties of the addition type liquid silicone rubber vulcanizate was small. Thus, in our practice, we have used chloroanilines to increase the vulcanization rate of addition-type liquid silicone rubbers. For every 100 parts of addition type liquid silicone rubber, 0.025-1.0 parts of p-chloroaniline can be introduced.
In addition to vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, platinum catalyst and halogenated aniline, one or more of reinforcing agent, pigment, color paste, color concentrate, heat conducting filler, electric conducting filler, antistatic agent, heat stabilizer, flame retardant, antibacterial agent, coupling agent, tackifier, structure controlling agent, mold release agent or low-cost filler can be contained in the addition type liquid silicone rubber according to requirements on performance, process and cost;
the reinforcing agent is one or more of fumed silica, precipitated silica, MQ silicon resin, cage polysilsesquioxane, organic montmorillonite and nano alumina, wherein the specific surface area of the silica is 100-500 m 2 The MQ silicone resin is methyl MQ silicone resin, hydrogen-containing MQ silicone resin, vinyl MQ silicone resin or phenyl MQ silicone resin;
the pigment is an inorganic pigment or an organic pigment;
the color paste is a mixture containing pigment and silicone oil and is in paste form;
the color paste is also a mixture containing pigment and silicone oil, and the viscosity of the color paste is lower than that of the color paste or similar to that of the color paste;
the color concentrate is metal complex dye or metal complex dye dissolved in solvent and/or silicone oil;
The heat conducting filler is one or more of aluminum oxide, aluminum nitride, magnesium oxide, zinc oxide, boron nitride, silicon carbide, silicon micropowder, fibrous carbon powder, scaly carbon powder, graphite or graphene; optionally, the thermally conductive filler is treated with a silane coupling agent, a titanate coupling agent, or a polymer compatibilizer; the polymer compatilizer is maleic anhydride grafted silicone rubber, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted ABS, or maleic anhydride grafted EVA, maleic anhydride grafted EPDM, maleic anhydride grafted SEBS, and maleic anhydride grafted POE;
the conductive filler is conductive carbon black, carbon fiber, graphite fiber, carbon nano tube, graphene, intrinsic conductive polymer, metal powder, metal fiber, metal-plated particles and metal-plated glass fiber; the intrinsic conductive polymer can be polyacetylene, polypyrrole, polythiophene, polyphenylene, polyphenylacetylene or polyaniline.
The antistatic agent is one or two of a macromolecular permanent antistatic agent, a nonionic antistatic agent, an anionic antistatic agent and a cationic antistatic agent;
the heat stabilizer is ferric hydroxide, ferric oxide, ferric octoate, organic silicon ferrocene, zinc oxide, tin dioxide, zirconium octoate, cesium octoate, lithium carbonate, cerium oxide or cerium-containing polysiloxane.
The flame retardant is one or a combination of more than one of aluminum hydroxide, magnesium hydroxide, halogen-containing flame retardant, phosphorus-containing flame retardant, nitrogen-containing flame retardant, antimony-containing flame retardant, boron-containing flame retardant, silicon-containing flame retardant and platinum-containing flame retardant;
the antibacterial agent is an inorganic antibacterial agent or an organic antibacterial agent;
the coupling agent is a silane coupling agent or a titanate coupling agent; preferably, the coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, gamma-glycidoxypropyl trimethoxysilane, N-beta-aminoethyl-gamma-aminopropyl trimethoxysilane, gamma- (methacryloyloxy) propyltrimethoxysilane and gamma-aminopropyl triethoxysilane.
The tackifier is grafted modified polysiloxane, copolymer of siloxane, polymer of siloxane grafted modification or hydrolysate of one or more of the above coupling agents under the action of acid catalyst.
The structuring control agent is at least one of silazane, dimethyl diethoxy silane, dimethyl dimethoxy silane and alpha, omega-dihydroxy polydimethylsiloxane; optionally, the silazane treating agent is hexamethyldisilazane or vinyl silazane;
The release agent is wax, ester wax, fluorine-containing release agent, higher fatty alcohol, higher fatty acid or metal salt of higher fatty acid; optionally, the release agent is one or more of stearic acid, zinc stearate, magnesium stearate or calcium stearate;
the low-cost filler is one or more of simethicone, precipitated silica, silica fume, diatomite, kaolin, talcum powder, calcium sulfate or calcium carbonate.
The invention also provides a preparation method of the liquid silicone rubber with the halogenated aniline and the vulcanized rubber thereof.
The method for introducing halogenated aniline into the single-component addition type liquid silicone rubber comprises the following steps:
1) Adding 0.0025-5.0% of halogenated aniline based on the weight of the added liquid silicone rubber, and uniformly stirring to obtain the added liquid silicone rubber containing halogenated aniline;
2) Vulcanizing and molding the obtained addition type liquid silicone rubber containing halogenated aniline at room temperature or elevated temperature to obtain addition type liquid silicone rubber vulcanized rubber; or, the obtained addition type liquid silicone rubber containing halogenated aniline and metal or nonmetal solid are placed together, and vulcanization molding is carried out at room temperature or elevated temperature, so that the composite of the addition type liquid silicone rubber vulcanized rubber and the metal or nonmetal solid is obtained.
The method for introducing halogenated aniline into the two-component addition type liquid silicone rubber comprises the following steps:
1) Adding halogenated aniline accounting for 0.0025-5.0% of the total weight of the added liquid silicone rubber A rubber and the added liquid silicone rubber B rubber to be stirred uniformly to obtain the added liquid silicone rubber containing halogenated aniline; or adding 0.0025% -5.0% of halogenated aniline based on the total weight of the addition type liquid silicone rubber A rubber and the addition type liquid silicone rubber B rubber into the addition type liquid silicone rubber A rubber or the addition type liquid silicone rubber B rubber, or adding 0.0025% -5.0% of halogenated aniline based on the total weight of the addition type liquid silicone rubber A rubber and the addition type liquid silicone rubber B rubber into the process of preparing the addition type liquid silicone rubber A rubber and/or the addition type liquid silicone rubber B rubber containing alkenyl polysiloxane, hydrogen-containing silicon bond, white carbon black, platinum catalyst and inhibitor, and then mixing the obtained A rubber and B rubber, and uniformly stirring to obtain the addition type liquid silicone rubber containing the halogenated aniline.
2) Vulcanizing and molding the obtained addition type liquid silicone rubber containing halogenated aniline at room temperature or elevated temperature to obtain addition type liquid silicone rubber vulcanized rubber; or, the obtained addition type liquid silicone rubber containing halogenated aniline and metal or nonmetal solid are placed together, and vulcanization molding is carried out at room temperature or elevated temperature, so that the composite of the addition type liquid silicone rubber vulcanized rubber and the metal or nonmetal solid is obtained.
The above metal or nonmetal solid means thermoplastic plastics, thermosetting rubber, thermoplastic rubber, metal, glass, ceramics, enamel, cement, leather, bamboo block, wood block, fiber braid or nonwoven fabric, and the metal or nonmetal solid may have a partial or complete plating, coating or undercoating. The plating or coating may be localized or the plating and coating may cover the entire surface of the metallic or nonmetallic solid. These metallic or non-metallic solid surfaces may be treated with a primer to promote adhesion to the liquid silicone rubber prior to compounding the addition-type liquid silicone rubber to ensure the bond strength between the liquid silicone rubber vulcanizate and the plastic.
The vulcanization molding is compression molding, injection molding, calendaring or extrusion vulcanization molding.
Thermoplastic and thermoplastic rubbers have softening temperatures or heat distortion temperatures below 200 ℃. The softening temperature of some thermoplastics such as polyethylene and polystyrene and some thermoplastic rubbers such as SBS and SEBS is even below 100 ℃. Although the bamboo or wood pieces do not soften at high temperatures, when the temperature exceeds 120 ℃, the bamboo or wood pieces discolor and become zoomed. Therefore, when the addition type liquid silicone rubber is heat-vulcanized with these thermoplastics, thermoplastic rubbers, bamboo or wood blocks, the vulcanization temperature must be low enough to be lower than their softening temperature or discoloration and zooming temperature.
Even if thermoplastic plastics, thermosetting plastics, thermoplastic rubbers, thermosetting rubbers and fibers with high thermal deformation temperature or thermal decomposition temperature are used, even metal or nonmetal materials with high melting point, when the thermoplastic plastics, thermosetting plastics, thermoplastic rubbers, thermosetting rubbers and fibers and addition type liquid silicone rubber are subjected to hot vulcanization molding, due to the introduction of halogenated aniline, the vulcanization speed can be increased, the vulcanization time can be shortened, or the vulcanization can be completed quickly at a lower vulcanization temperature, so that the energy consumption can be reduced, and the production efficiency can be improved.
The beneficial effects are that: the present patent application discloses a method for adding halogenated aniline into addition type liquid silicone rubber to improve the reactivity of the addition type liquid silicone rubber, which has the following advantages:
(1) Shortening the positive vulcanization time of the liquid silicone rubber, thereby having the effects of saving energy, improving production efficiency and reducing production cost. By adding the halogenated aniline, the positive vulcanization time of the liquid silicone rubber prepared by the invention is obviously shortened, and meanwhile, the physical and mechanical properties of the obtained vulcanized silicone rubber, such as hardness, tensile strength, elongation at break and the like, are basically unchanged.
(2) The vulcanization temperature of the liquid silicone rubber is reduced. The vulcanization temperature of the liquid silicone rubber can be reduced while maintaining the vulcanization time substantially unchanged. This makes the liquid silicone rubber suitable for heat vulcanization bonding with thermoplastic parts, bamboo or wood blocks, etc. having a low heat distortion temperature.
(3) The amount of noble metal platinum in the liquid silicone rubber can be suitably reduced while maintaining the vulcanization temperature and the vulcanization time substantially unchanged.
(4) The cost of the raw materials required by the invention is low, and the halogenated aniline is cheap and easy to obtain.
(5) The method disclosed by the invention is simple and convenient, and does not need a process for preparing a platinum catalyst. The halogenated aniline can be directly added into the addition type liquid silicone rubber, or the halogenated aniline is added in the process of preparing the addition type liquid silicone rubber, so that the effect of improving the reactivity of the addition type liquid silicone rubber can be generated.
Detailed Description
The invention will be further illustrated with reference to specific examples. The test methods in the following specific examples and comparative examples are described below:
positive vulcanization time: the positive vulcanization time is divided into theoretical positive vulcanization time and process positive vulcanization time. The process plus cure time is the most favorable cure time for the rubber curing process. In the invention, the positive vulcanization time refers to the positive vulcanization time of the process, which is abbreviated as positive vulcanization time, and the torque in the vulcanization curve is [ ML+ (MH-ML) ×90%]Corresponding to a time in which ML is the minimum torque and MH is the maximum torque. The positive vulcanization time is T 90 And (3) representing.
Scorch time: scorch time is the torque in the cure curve [ ML+ (MH-ML) ×10% ]]The corresponding time, which means that the compound has reached a degree of crosslinking of 10%, the plasticity is poor and it is not suitable for processing. The scorch time is from T 10 And (3) representing. In the invention, the positive vulcanization time and the scorch time are measured by a rotor-free vulcanization tester.
Density: the densities of the silicone rubber vulcanizates in each example and each comparative example were measured using method A according to the method specified in "measurement of densities of vulcanized rubbers or thermoplastic rubbers" of GB/T533-2008.
Hardness: according to "GB/T531.1-2008 vulcanized rubber or thermoplastic rubber press-in hardness test method part 1: the shore a hardness of the silicone rubber vulcanizate of each example and each comparative example was measured using a shore a durometer, as specified in shore durometer (shore hardness) ".
Tensile strength and elongation at break: the tensile strength and elongation at break of the silicone rubber in each of examples and comparative examples were measured by a tensile tester using a type I sample according to the method specified in "measurement of tensile stress strain properties of vulcanized rubber or thermoplastic rubber" in GB/T528-2009.
Tear strength: the tear strength (rectangular specimen) of the silicone rubber in each of examples and comparative examples was measured by a tensile tester according to the method specified in "measurement of tear strength of vulcanized rubber or thermoplastic rubber (trouser, rectangular specimen, and crescent specimen)" of GB/T529-2008.
Compression set: according to "GB/T1683-2018 vulcanizate: method for measuring permanent deformation compression set the compression set of the silicone rubber in each of examples and comparative examples was measured using a compression ratio of 40%.
Example 1:
the embodiment provides a single-component addition type liquid silicone rubber, which comprises the following raw materials: 20 parts of low-viscosity vinyl silicone oil, 50 parts of high-viscosity vinyl silicone oil, 20 parts of white carbon black, 5 parts of hexamethyldisilazane, 1 part of high-vinyl silicone oil, 1.5 parts of water, 2 parts of hydrogen-containing silicone oil, 0.2 part of platinum complex and 0.02 part of 3-methyl-1-dodecyn-3-ol, and 1 part of p-chloroaniline, wherein the viscosity of the low-viscosity vinyl silicone oil is 8000cSt; the high viscosity vinyl silicone oil has a viscosity of 60000cSt; the vinyl content of the high vinyl silicone oil is 7%; the platinum content of the methyl vinyl siloxane coordinated platinum complex was 2000ppm; the specific surface area of the white carbon black is 200m 2 /g; the hydrogen content of the hydrogen-containing silicone oil is 0.36%; the vinyl content of the low-viscosity vinyl silicone oil is 0.3%; the vinyl content of the high-viscosity vinyl silicone oil was 0.16%.
The preparation method of the one-component addition type liquid silicone rubber comprises the following steps: weighing 20kg of low-viscosity vinyl silicone oil, 50kg of high-viscosity vinyl silicone oil, 5kg of hexamethyldisilazane, 1.5kg of water and 1kg of high-vinyl silicone oil, putting into a kneader, and kneading for 2.5 hours at 65 ℃; adding 20kg of white carbon black in 5 batches, heating to 120 ℃, and kneading for 1h; heating to 175 ℃; vacuumizing, and continuously kneading for 4 hours to obtain the liquid silicone rubber base material.
Adding the liquid silicone rubber base material into a stirrer, and introducing ice water to the wall of a cylinder body of the stirrer; 2kg of hydrogen-containing silicone oil and 0.02kg of 3-methyl-1-dodecene-3-ol and 1kg of p-chloroaniline are added and stirred for 15min; 0.2kg of platinum complex is added, vacuumized and stirred for 0.5 hour at 30 ℃; and (3) uniformly stirring and discharging to obtain the single-component addition type liquid silicone rubber, and marking the single-component addition type liquid silicone rubber as formula 101.
The formulation and process of the one-component addition type liquid silicone rubber prepared in comparative example 1 were the same as those of example 1, except that p-chloroaniline was not added. The one-component addition type liquid silicone rubber produced in comparative example 1 was labeled "formulation 100".
The two compounds were tested for their vulcanization characteristics at 120℃in 60 minutes after their preparation by means of a vulcanizing instrument of model FR-2117 from Shanghai Breast instruments and technology, inc. The test specimen was prepared by vulcanization at 120℃for 120 s.
TABLE 1 influence of para-chloroaniline on the vulcanization Properties and Properties of one-component addition type liquid Silicone rubber
As can be seen from Table 1, the addition of p-chloroaniline in formulation 101 significantly shortens the time to cure the one-component addition-type liquid silicone rubber. The formula 100 is vulcanized for 60s at 120 ℃, the obtained vulcanized rubber is not cooked at all, the Shore A hardness of the vulcanized rubber is 6, the vulcanization speed of the formula 101 is obviously increased due to the fact that the p-chloroaniline is contained, and the Shore A hardness of the obtained vulcanized rubber is 43 when the vulcanized rubber is vulcanized for 60s at 120 ℃. When the curing time was 75s, the hardness of the cured glue of formulation 100 was 40, while the hardness of the cured glue of formulation 101 was 45. When the cure time was 120s, the Shore A hardness of the vulcanizates of both formulation 100 and formulation 101 was 45.
It is noted that although the time to cure is significantly different between formulation 100 and formulation 101, the resulting vulcanizate has substantially the same hardness, tensile strength, elongation at break, and tear strength after curing, as shown in Table 1.
Example 2:
this example provides a two-component addition type liquid silicone rubber, which was prepared as formulation 200 and formulation 201, respectively. Formulation 201 was prepared as follows:
preparation of adhesive A: 100 parts of vinyl silicone oil (viscosity 500 cSt) with a vinyl content of 0.16wt%, 0.5 part of platinum catalyst (the platinum catalyst is added in the form of a solution with a platinum concentration of 1000 ppm) and 20 parts of white carbon black are taken. After weighing each component, mixing each component at normal temperature, and uniformly stirring for 1h for later use.
And (3) preparation of the adhesive B: taking 100 parts of vinyl silicone oil (viscosity 500 cSt), wherein the vinyl content of the vinyl silicone oil is 0.16%; 30 parts by weight of hydrogen-containing silicone oil (hydrogen content of 1.60%); 0.02 part of alkyne inhibitor (3, 5-dimethyl-1-hexyn-3-ol) and 1.0 part of parachloroaniline; after weighing, the components are mixed at normal temperature and stirred for 1h for later use.
Mixing the adhesive A and the adhesive B according to the proportion of 1:1, stirring for 0.5h, introducing into a mould, and pumping air bubbles in a vacuum oven for 30min. Standing for a period of time to obtain the liquid silicone rubber.
The preparation method of the formula 200 is basically the same as that of the formula 201, but p-chloroaniline is not added in the preparation of the glue B.
The vulcanization characteristics of the formulations 200 and 201 were tested at a vulcanization temperature of 110℃using a vulcanizing machine of model FR-2117 manufactured by Shanghai Fair instruments and technology Co., ltd, and the hardness of the vulcanized rubber produced by the formulations 200 and 201 under different vulcanization conditions was tested. The test results obtained are shown in Table 2.
TABLE 2 influence of p-chloroaniline on vulcanization Properties and Properties of two-component addition type liquid Silicone rubber
As can be seen from Table 2, the addition of p-chloroaniline significantly shortened the time of the positive vulcanization of the two-component addition type liquid silicone rubber. The formula 200 is vulcanized for 60s at 110 ℃, the obtained vulcanized rubber is not cooked at all, the Shore A hardness is only 5, and the vulcanization speed of the formula 201 is obviously increased due to the fact that the p-chloroaniline is contained, and the Shore A hardness of the obtained vulcanized rubber is 41 when the vulcanized rubber is vulcanized for 60s at 110 ℃. When the curing time was 75s, the hardness of the cured gel of formulation 200 was 38, and the hardness of the cured gel of formulation 201 was 45. When the vulcanization times were 120s each. The Shore A hardness of the vulcanizates of formulations 200 and 201 were both 45.
Thus, the addition of the parachloroaniline can obviously shorten the vulcanization time of the addition type liquid silicone rubber, and has no influence on the hardness of the vulcanized rubber which can be achieved at a given vulcanization temperature.
Example 3:
the addition type liquid silicone rubber A and B are commercially available, and the addition type liquid silicone rubber KE-1950-5A and B produced by the Xinyue corporation of Japan are selected in the embodiment, wherein the A contains vinyl silicone oil, white carbon black and platinum catalyst, and the B contains vinyl silicone oil, white carbon black, hydrogen-containing siloxane and inhibitor.
Each formulation based on KE-1950-5A and B gums had vulcanization characteristics and physical properties as shown in Table 3.1. The vulcanization conditions for preparing the physical property test sample were 110 ℃ x 180s.
TABLE 3.1 vulcanization Properties and Properties of formulations based on KE-1950-5A and B gums
As can be seen from Table 3.1, when the vulcanization temperature is 110Scorch time T of the addition type liquid silicone rubber (formulation 301 to 305) to which p-chloroaniline was added, compared with the addition type liquid silicone rubber (formulation 300) to which p-chloroaniline was not added at C 10 And time of positive vulcanization T 90 Obviously shortens, and shows that the p-chloroaniline can obviously improve the vulcanization speed of the addition type liquid silicone rubber. As for the manner of adding p-chloroaniline (as shown in the description of the formulation in Table 3.1), the scorch time T was measured 10 And time of positive vulcanization T 90 Is not so much affected. As can also be seen from Table 3.1, the physical properties of the addition type liquid silicone rubber vulcanizates (formulations 301-305) added with para-chloroaniline, such as hardness, tensile strength, elongation at break, compression set, linear shrinkage, etc., remained substantially unchanged or did not change much as compared to the addition type liquid silicone rubber vulcanizates (formulation 300) without para-chloroaniline. Table 3.1 shows that the addition of p-chloroaniline only significantly increases the vulcanization rate of the addition type liquid silicone rubber, while hardly affecting the physical properties of the addition type liquid silicone rubber vulcanizate.
Mixing different amounts of parachloroaniline with addition type liquid silicone rubber (KE-1950-5A rubber and B rubber of Xinyue Co., ltd.), stirring, measuring vulcanization curve at 110deg.C, and obtaining scorch time T of each formula 10 And time of positive vulcanization T 90 . The effect of the amount of p-chloroaniline added on the vulcanization characteristics of the addition type liquid silicone rubber at a vulcanization temperature of 110℃is shown in Table 3.2.
TABLE 3.2 influence of the addition amount of p-chloroaniline on the vulcanization characteristics of addition type liquid silicone rubber
As can be seen from Table 3.2, even when a small amount of p-chloroaniline (e.g., formulation 311, the addition amount of p-chloroaniline was 0.1% of that of the addition type liquid silicone rubber), scorch time T of the addition type liquid silicone rubber 10 And time of positive vulcanization T 90 And also significantly shortened.
The formulations 310 and 312 were vulcanized at different vulcanization temperatures, respectively, and the two were measuredScorch time T of the formulation at different vulcanization temperatures 10 And time of positive vulcanization T 90 The test results are shown in table 3.3.
TABLE 3.3 influence of vulcanization temperature on vulcanization characteristics of addition type liquid Silicone rubber
As can be seen from Table 3.3, the addition type liquid silicone rubber containing p-chloroaniline (formulation 312) exhibited significantly shorter time and significantly faster cure rate than the addition type liquid silicone rubber without p-chloroaniline (formulation 310) at different cure temperatures. The plus cure time for the addition liquid silicone rubber containing p-chloroaniline (formulation 312) was 170.5s, while the plus cure time for the addition liquid silicone rubber without p-chloroaniline (formulation 310) was 267.4s at a cure temperature of 100 ℃. The addition of p-chloroaniline shortens the time for positive vulcanization by about one third. The plus cure time of the p-chloroaniline containing addition liquid silicone rubber (formulation 312) at a cure temperature of 130℃was 25.1s, while the plus cure time of the p-chloroaniline free addition liquid silicone rubber (formulation 310) at a cure temperature of 135℃was 26.4s ℃. That is, the addition of p-chloroaniline can reduce the curing temperature by 5℃when the time of the forward curing is the same or similar. The shortening of the vulcanizing time or the reduction of the vulcanizing temperature has positive significance for improving the production efficiency, saving the energy and reducing the production cost. Vulcanization at reduced vulcanization temperatures allows some thermoplastics (e.g., polypropylene, polycarbonate) to be non-softened and not thermally deformed during thermal vulcanization compounding with addition type liquid silicone rubber.
We also performed a comparative test: mixing peroxide vulcanized silicone rubber (peroxide vulcanized silicone rubber GF153 produced by Shenzhen Co., ltd.) and peroxide DCP at a ratio of 100:1 to obtain a rubber compound; GF153, DCP and parachloroaniline are mixed in a ratio of 100:1:1 to obtain another rubber compound. As measured by the vulcanization curve, we found that the scorch time and the forward vulcanization time of the two compounds were substantially identical. It can be seen that p-chloroaniline has no accelerating effect on the vulcanization of peroxide-curable silicone rubber.
Example 4:
the addition type liquid silicone rubber KE-1950-5A rubber and B rubber produced by the Japanese Xinyue corporation were mixed at a weight ratio of 1:1 at room temperature. Except for the formula 400, different additives (including various halogenated anilines and other compounds) are respectively added into the rest of the formula, 0.5 part or 1.0 part of one additive is added into each 100 parts of KE-1950-5A adhesive and B adhesive mixture, and the mixture is uniformly mixed, and one formula is obtained after each additive is added. The granulated additive was ground into powder using an agate mortar prior to addition. The scorch time and the forward cure time of each mix were measured with a vulcanizer at a vulcanization temperature of 110℃and the results obtained are shown in Table 4.
TABLE 4 influence of halogenated anilines and other mixtures on vulcanization speed
As can be seen from Table 4, the addition of aniline and halogenated anilines including p-chloroaniline, m-chloroaniline, o-chloroaniline, 4-fluoroaniline, 4-bromoaniline has an obvious effect of promoting the vulcanization of the addition type silicone rubber, and can significantly shorten the positive vulcanization time of the addition type silicone rubber, see formulas 400-406. But aniline has a larger influence on scorch time while reducing positive vulcanization time, and the shortening range of the scorch time is larger, which is not beneficial to the safe use of sizing materials. In addition, aniline is a volatile liquid, has strong odor, is harmful to the environment and human body, and acute aniline poisoning is one of the common occupational poisoning. In addition, aniline is added into the liquid silicone rubber, so that the rubber material has an pungent smell and the color of the rubber material is changed. Therefore, the practicality of aniline in liquid silicone rubber is poor.
Other compounds, including acetanilide and benzylamine, have little effect on the time to cure or significantly extend the time to cure, see formulas 307-332. In the test, it was also found that when cyclohexane and 4-methylcyclohexylamine were added as additives in a relatively small amount (about 0.5%), the positive vulcanization time of the addition type liquid silicone rubber was remarkably prolonged, and when the addition amount was about 1%, the addition type liquid silicone rubber was not cured at 110 ℃, and could not be cured, and the torque measured by a vulcanizing machine was gradually increased all the time within a set vulcanization time (10 minutes), and the scorch time and the positive vulcanization time were not measured.
It can be seen that the halogenated aniline can significantly shorten the time for the positive vulcanization of the addition type liquid silicone rubber, and has a characteristic of promoting the vulcanization of the addition type liquid silicone rubber unlike other compounds.
Incidentally, when various halogenated anilines are incorporated into peroxide-cured silicone rubber, the time for positive curing cannot be shortened and better physical properties can be obtained. The addition of p-chloroaniline to various methyl vinyl silicone rubbers containing peroxide curing agents (such as KE-951-U manufactured by Xinyue corporation, SE-951 manufactured by Dow Corning corporation, or the rubber compound prepared by methyl vinyl raw rubber and fumed silica) obviously prolongs the normal curing time of the rubber compound. T containing 1% of a "double 25 vulcanizing agent" KE-951-U silicone rubber at 175 ℃C 10 And T 90 34.1s and 112.7s, respectively; after adding 1% of p-chloroaniline, T 10 And T 90 52.2s and 251.4s, respectively. "bis 25 vulcanizing agent" is a commonly used peroxide vulcanizing agent, and has the chemical name: 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane. From this, it can be seen that the halogenated aniline has no accelerating effect on the peroxide vulcanization of the methyl vinyl silicone rubber, but rather has a retarding effect.
Example 5:
circles with consistent sizes are uniformly distributed on a polypropylene flat plate with the thickness of 0.5mm, wherein the outer diameter of the circles is 24mm, and the inner diameter of the circles is 19mm. The area between the outer and inner diameters of the circle is the area where the liquid silicone rubber adheres to the polypropylene. The adhesion promoter for promoting the adhesion of the liquid silicone rubber and the polypropylene is coated on the part which needs to be adhered with the liquid silicone rubber, and the liquid silicone rubber is dried at room temperature or baked for 10 minutes at 70 ℃ for standby. The adhesion promoter is commercially available PP plastic surface treatment agent, such as PP-605 of Yunli technology Co., hangzhou or JS-501 of Dongguan plastic technology Co., ltd.
Using the formulations 310 and 312 of example 3, glue A and glue B of each formulation were injected into the surface of a polypropylene flat sheet in a 1:1 ratio using a liquid silicone rubber injection machine to form a silicone rubber ring on the polypropylene surface that was adhered to the polypropylene surface one by one. The outer diameter, inner diameter and thickness of the silicone rubber ring were 24mm, 19mm and 0.45mm, respectively.
The processing cycle of formulation 310 was 267.4s when the mold temperature of the liquid silicone rubber injection machine was 100 ℃. With formulation 312, the processing cycle time can be reduced to 170.5 seconds. That is, in the production, since the formula 312 contains p-chloroaniline, the vulcanized rubber of the liquid silicone rubber bonded on the polypropylene flat sheet with good vulcanization and good performance can be obtained every 170.5s, and the processing period is shortened by 96.9s compared with the formula 310 without adding p-chloroaniline, which is a considerable number. The reduction of the vulcanization time means energy saving and production efficiency improvement.
And punching the polypropylene with the silicone rubber ring to obtain the small disc which can be used as the sealing gasket in the bottle cap of the glass bottle or the plastic bottle. The sealing capability of the small disc is excellent, and a piece of small disc is placed in the bottle cap, so that liquid in the bottle can not leak.
Example 6:
example 6 is a method of further improving the production efficiency based on example 5. The compound of formulation 312 was injection molded onto the surface of the adhesion promoter treated polypropylene flat sheet as in example 5, vulcanized at a mold temperature of 100 c for 120s and the silicone rubber ring attached polypropylene flat sheet was removed. Although the 100 c x 120s vulcanization conditions do not sufficiently vulcanize the compound of formulation 312, the compound of formulation 312 is substantially set on a polypropylene flat sheet without plastic flow.
And (3) putting a plurality of the prepared polypropylene flat sheets attached with the silicone rubber rings into a baking oven at 90 ℃ to bake for 0.5-2.0h, taking out, and punching to obtain the polypropylene small sheets with the silicone rubber rings. In the small disc, the adhesion between the silicone rubber and the polypropylene is firm.
In contrast, the compound of formula 310 without para-chloroaniline was injection molded onto the surface of the adhesion promoter treated polypropylene flat sheet, vulcanized at a mold temperature of 100 ℃ for 120s, and the polypropylene flat sheet with the silicone rubber ring attached thereto was removed, and it was found that the silicone rubber was not cured, the silicone rubber ring was not set, plastic flow occurred, and the product was scrapped.
Example 7:
platinum catalysts are expensive. The addition type liquid silicone rubber A and B can be prepared by adding p-haloaniline to reduce the dosage of the platinum catalyst. This example also illustrates the addition of p-chloroaniline to reduce the amount of platinum catalyst when the A and B gums are mixed after the two component silicone rubbers A and B are prepared.
The addition type liquid silicone rubber KE-1950-5A rubber and the rubber B rubber produced by Japanese Xinyue Co were taken, wherein the rubber A contains a platinum catalyst. The compounds of formulations 300, 321 and 322 were formulated as described in the formulation in table 5. Test specimens were prepared under vulcanization conditions of 110 ℃ x 125 s.
TABLE 5 influence of Chloroamine on vulcanization Properties and Properties of addition type liquid Silicone rubber
As can be seen from Table 5, the addition of p-chloroaniline to formulation 322 resulted in a very close cure profile of the compound and physical properties of the resulting cured compound as compared to formulation 300 with a small amount of the A compound and a large amount of the B compound containing the platinum catalyst. The curing characteristics and physical properties of the cured rubber of the formulation 321 without p-chloroaniline are greatly different from those of the formulation 300, and the main characteristics are that the positive curing time is prolonged, the tensile strength is reduced, and the compression set is increased.
Thus, the addition of the p-chloroaniline can play a role in reducing the dosage of the adhesive containing the platinum catalyst A or reducing the dosage of the platinum catalyst under the condition of ensuring that the vulcanization characteristic and physical properties of the adhesive are basically unchanged, thereby reducing the cost of raw materials.
Example 8:
100 parts of addition type liquid silicone rubber KE-1950-5A rubber and 100 parts of addition type liquid silicone rubber B rubber produced by Japanese Xinyue corporation, and 1.0 part of parachloroaniline are taken and uniformly mixed to obtain the addition type liquid silicone rubber containing parachloroaniline. One side of a bamboo block 2.6cm long, 1.7cm wide and 0.5cm thick was printed with a layer of adhesion promoter consisting of chloroplatinic acid-tetramethyl tetravinyl cyclotetrasiloxane and a tacanine silane coupling agent Z-6040 in a size of 2.55X1.65 cm. And placing the bamboo blocks into a die cavity of a die. The obtained liquid silicone rubber containing p-chloroaniline was placed on the side with adhesion promoter and vulcanized under vulcanization conditions of 110℃X 80s to obtain a bamboo block having a layer of silicone rubber with a thickness of 0.5 mm. And (3) punching holes on the bamboo blocks, and connecting a plurality of bamboo blocks by nylon wires to prepare the anti-skid bamboo mat.
When p-chloroaniline in the formula is removed, the vulcanized rubber obtained by vulcanization under the vulcanization condition of 110 ℃ multiplied by 80s is sticky, and the vulcanization is not cooked.
Claims (10)
1. An addition type liquid silicone rubber, which is characterized in that: containing 0.0025 to 5.0% by weight of a halogenated aniline based on the weight of the addition liquid silicone rubber; the addition type liquid silicone rubber is an elastomer material with a three-dimensional network structure formed by the addition reaction of polysiloxane containing hydrogen silicon bonds and polysiloxane containing alkenyl groups serving as cross-linking agents under the action of a platinum catalyst;
the polysiloxane containing alkenyl is selected from one or more of polysiloxane containing only alkenyl, polysiloxane containing only alkenyl and polysiloxane containing both alkenyl and alkenyl; the viscosity of the polysiloxane containing alkenyl is 5000-100000cP, and the alkenyl content is 0.025wt% to 2.5wt% respectively; the polysiloxane containing alkenyl is polysiloxane or silicone oil containing vinyl, allyl or propenyl;
the polysiloxane containing hydrogen-silicon bond is one or more of hydrogen-silicon oil, hydrogen-silicon resin or hydrogen-silicon bond polysilsesquioxane; the hydrogen-containing silicone oil is selected from one or more of silicone oil containing only terminal hydrogen groups, silicone oil containing only lateral hydrogen groups and silicone oil containing both terminal hydrogen groups and lateral hydrogen groups, and the hydrogen content of the hydrogen-containing silicone oil is 0.1-1.6 wt%; the hydrogen-containing silicone resin is a polysiloxane polymer with a cross-linked structure, wherein the molecular chain of the polysiloxane polymer contains a plurality of hydrogen-silicon bonds; the hydrogen-containing silicon bond polysilsesquioxane is in a trapezoid, branch or cage structure, and each polysilsesquioxane molecule at least contains two hydrogen silicon bonds.
2. An addition type liquid silicone rubber according to claim 1, characterized in that: the addition type liquid silicone rubber comprises the following raw materials in parts by weight: 100 parts of polysiloxane containing alkenyl, 2-30 parts of polysiloxane containing hydrogen silicon bond, 5-100 parts of white carbon black, 0.005-5 parts of platinum catalyst, 0.001-1 part of inhibitor and 0.05-5 parts of halogenated aniline, wherein the platinum catalyst is in the form of solution, paste or solid silicone rubber raw colloid or powder, and the mass concentration of platinum atoms is 100-10000ppm or the content of platinum atoms is 1-100 wt%.
3. An addition type liquid silicone rubber according to claim 1, characterized in that: the addition type liquid silicone rubber is a mixture formed by mixing an A rubber and a B rubber in a weight ratio of 10:1-1:10, wherein the A rubber contains polysiloxane containing alkenyl, white carbon black and a platinum catalyst, the B rubber contains polysiloxane containing alkenyl, white carbon black and polysiloxane containing hydrogen silicon bond and an inhibitor, and the A rubber and/or the B rubber contains halogenated aniline or the mixture of the A rubber and the B rubber contains halogenated aniline.
4. An addition type liquid silicone rubber according to claim 2, characterized in that: the inhibitor is one or two of methylbutynol, 1-ethynyl cyclohexanol, 3, 5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-methyl-3-butyn 2-ol, 4-trimethylsilicon-3-butyn-2-ol, phenyl (trimethylbutynyloxy) silane, vinyl (trimethylbutynyloxy) silane, methyltri (cyclohexylynyloxy) silane, dimethyl butynyldicarboxylate, hexaallyl m-trimellitamide, diallyl maleate, azobenzene-4, 4' -dicarboxylic acid dimethyl ester, N-phenyl-1, 2, 4-triazolin dione, N-methyl-1, 2, 4-triazolin dione, polydivinyl tetramethyl disiloxane, tetravinyl tetramethyl cyclodisiloxane and tetramethyl divinyl disiloxane;
The platinum catalyst is selected from one or more of chloroplatinic acid, ammonium hexachloroplatinate, potassium chloroplatinite, potassium trichloroplatinate, tetraamminoplatinate, cis-dichloro diammineplatinum (II), tetraamminoplatinate (II), dinitroso diammineplatinum or hexachloroplatinic acid sodium, tetrakis (triphenylphosphine) platinum, platinum acetylacetonate, platinum trifluoroacetylacetonate, platinum hexafluoroacetylacetonate or benzoylacetonate, alcohol modified chelate of chloroplatinic acid, tetrahydrofuran coordinated platinum chelate, acetylacetonate chelate of chloroplatinic acid, chloroplatinic acid-methyl vinyl siloxane complex, chloroplatinic acid-divinyl tetramethyl disiloxane complex, chloroplatinic acid-tetramethyl tetravinyl cyclosiloxane, hot melt polymer coated platinum compound, platinum powder, platinized powder, supported platinum catalyst, bimetallic catalyst containing platinum;
the hot melt polymer is cyclodextrin, acrylic resin, styrene resin or silicone resin.
5. An addition type liquid silicone rubber according to claim 1, wherein the halogenated aniline is one, two or more of o-fluoroaniline, m-fluoroaniline, p-fluoroaniline, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline, m-bromoaniline and p-bromoaniline.
6. An addition type liquid silicone rubber according to any one of claims 1 to 5, wherein said halogenated aniline is p-chloroaniline, and 0.025 to 1.0 part by weight of p-chloroaniline is blended per 100 parts by weight of said addition type liquid silicone rubber.
7. An addition type liquid silicone rubber according to claim 1, characterized in that: the addition type liquid silicone rubber also contains one or more of reinforcing agents, pigments, color pastes, color concentrates, heat conducting fillers, conductive fillers, antistatic agents, heat stabilizers, flame retardants, antibacterial agents, coupling agents, adhesion promoters, structure control agents, release agents or low-cost fillers;
the reinforcing agent is one or more of fumed silica, precipitated silica, MQ silicon resin, cage polysilsesquioxane, organic montmorillonite and nano alumina, wherein the specific surface area of the silica is 100-500 m 2 The MQ silicone resin is methyl MQ silicone resin, hydrogen-containing MQ silicone resin, vinyl MQ silicone resin or phenyl MQ silicone resin;
the pigment is an inorganic pigment or an organic pigment;
the color paste is a mixture containing pigment and silicone oil and is in paste form;
the color paste is also a mixture containing pigment and silicone oil, and the viscosity of the color paste is lower than that of the color paste;
The color concentrate is metal complex dye or metal complex dye dissolved in solvent and/or silicone oil;
the heat conducting filler is one or more of aluminum oxide, aluminum nitride, magnesium oxide, zinc oxide, boron nitride, silicon carbide, silicon micropowder, fibrous carbon powder, scaly carbon powder, graphite or graphene; optionally, the thermally conductive filler is treated with a silane coupling agent, a titanate coupling agent, or a polymer compatibilizer; the polymer compatilizer is maleic anhydride grafted silicone rubber, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted ABS, or maleic anhydride grafted EVA, maleic anhydride grafted EPDM, maleic anhydride grafted SEBS, and maleic anhydride grafted POE;
the conductive filler is conductive carbon black, carbon fiber, graphite fiber, carbon nano tube, graphene, intrinsic conductive polymer, metal powder, metal fiber, metal-plated particles and metal-plated glass fiber;
the antistatic agent is one or two of a macromolecular permanent antistatic agent, a nonionic antistatic agent, an anionic antistatic agent and a cationic antistatic agent;
the heat stabilizer is ferric hydroxide, ferric oxide, ferric octoate, organic silicon ferrocene, zinc oxide, tin dioxide, zirconium octoate, cesium octoate, lithium carbonate, cerium oxide or cerium-containing polysiloxane;
The flame retardant is one or the combination of more than two of aluminum hydroxide, magnesium hydroxide, halogen-containing flame retardant, phosphorus-containing flame retardant, nitrogen-containing flame retardant, antimony-containing flame retardant, boron-containing flame retardant, silicon-containing flame retardant and platinum-containing flame retardant;
the antibacterial agent is an inorganic antibacterial agent or an organic antibacterial agent;
the coupling agent is a silane coupling agent or a titanate coupling agent;
the tackifier is grafted modified polysiloxane, a copolymer of siloxane, a polymer modified by siloxane grafting or hydrolysate of one or more of the coupling agents under the action of an acid catalyst;
the structuring control agent is at least one of silazane, dimethyl diethoxy silane, dimethyl dimethoxy silane and alpha, omega-dihydroxy polydimethylsiloxane; the silazane is hexamethyldisilazane or vinyl silazane;
the release agent is wax, fluorine-containing release agent, higher fatty alcohol, higher fatty acid or metal salt of higher fatty acid;
the low-cost filler is simethicone, precipitated silica, silica fume, diatomite, kaolin, talcum powder, calcium sulfate or calcium carbonate.
8. A method for preparing the addition type liquid silicone rubber and vulcanized rubber thereof according to claim 1, which is characterized in that: the method comprises the following steps:
1) Adding 0.0025-5.0% of halogenated aniline based on the weight of the addition type liquid silicone rubber into the addition type liquid silicone rubber containing alkenyl polysiloxane, hydrogen-containing silicon bond polysiloxane, white carbon black, platinum catalyst and inhibitor or in the process of preparing the addition type liquid silicone rubber containing alkenyl polysiloxane, hydrogen-containing silicon bond polysiloxane, white carbon black, platinum catalyst and inhibitor, and uniformly stirring to obtain the addition type liquid silicone rubber containing halogenated aniline;
2) Vulcanizing and molding the obtained addition type liquid silicone rubber containing halogenated aniline at room temperature or elevated temperature to obtain addition type liquid silicone rubber vulcanized rubber; or, the obtained addition type liquid silicone rubber containing halogenated aniline and metal or nonmetal solid are placed together, and vulcanization molding is carried out at room temperature or elevated temperature, so that the composite of the addition type liquid silicone rubber vulcanized rubber and the metal or nonmetal solid is obtained.
9. A method for preparing the addition type liquid silicone rubber and vulcanized rubber thereof according to claim 1, which is characterized in that: the method comprises the following steps:
1) Adding halogenated aniline accounting for 0.0025-5.0% of the total weight of the added liquid silicone rubber A rubber and the added liquid silicone rubber B rubber to be stirred uniformly to obtain the added liquid silicone rubber containing halogenated aniline; or adding 0.0025% -5.0% of halogenated aniline based on the total weight of the addition type liquid silicone rubber A and the addition type liquid silicone rubber B into the addition type liquid silicone rubber A or the addition type liquid silicone rubber B, or adding 0.0025% -5.0% of halogenated aniline based on the total weight of the addition type liquid silicone rubber A and the addition type liquid silicone rubber B in the process of preparing the addition type liquid silicone rubber A and/or the addition type liquid silicone rubber B, and then mixing the obtained addition type liquid silicone rubber A and the obtained addition type liquid silicone rubber B, and uniformly stirring to obtain the addition type liquid silicone rubber containing the halogenated aniline;
2) Vulcanizing and molding the obtained addition type liquid silicone rubber containing halogenated aniline at room temperature or elevated temperature to obtain addition type liquid silicone rubber vulcanized rubber; or, the obtained addition type liquid silicone rubber containing halogenated aniline and metal or nonmetal solid are placed together, and vulcanization molding is carried out at room temperature or elevated temperature, so that the composite of the addition type liquid silicone rubber vulcanized rubber and the metal or nonmetal solid is obtained.
10. A process for the preparation of addition type liquid silicone rubber and its vulcanizate according to claim 8 or 9, wherein the metal or nonmetal solid is thermoplastic, thermosetting plastic, thermosetting rubber, thermoplastic rubber, metal, glass, ceramic, enamel, cement, leather, bamboo block, wood block, fiber braid or nonwoven; the metal or nonmetal solid is plated, coated or undercoated; the vulcanization molding is compression molding, injection molding, calendaring or extrusion vulcanization molding.
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