阅读说明：本技术 一种高温硅橡胶乳液及其制备方法和应用 (High-temperature silicone rubber emulsion and preparation method and application thereof ) 是由 蔡克平 陈俐 郭舜华 于 2019-12-03 设计创作，主要内容包括：本发明公开了一种高温硅橡胶乳液,其原料包括：硅橡胶50～100份,油性乳化剂5～10份,水性乳化剂3.5～10份,pH调节剂5～10份,机械稳定剂0.5～1.0份,软水450～990份。该高温硅橡胶乳液中硅橡胶的粘度大大降低,拓展了涂覆薄制品范围,并有效改善涂覆工艺可靠性和效率,提高涂覆织物厚度的均匀性和质量稳定性。本发明还公开了该高温硅橡胶乳液的制备方法和应用,将硅橡胶与油性乳化剂加热混合均匀后,加入到含水性乳化剂的水相中,乳化成均相的高温硅橡胶乳液。制备的海绵撕裂强度和拉伸强度高,发泡率和弹性好；制备的皮革可以任意制备涂层厚度,能有效提高皮革耐老化性能。(The invention discloses a high-temperature silicone rubber emulsion which comprises the following raw materials: 50-100 parts of silicon rubber, 5-10 parts of an oily emulsifier, 3.5-10 parts of a water-based emulsifier, 5-10 parts of a pH regulator, 0.5-1.0 part of a mechanical stabilizer and 450-990 parts of soft water. The viscosity of the silicone rubber in the high-temperature silicone rubber emulsion is greatly reduced, the range of coating thin products is expanded, the reliability and efficiency of a coating process are effectively improved, and the thickness uniformity and quality stability of coated fabrics are improved. The invention also discloses a preparation method and application of the high-temperature silicone rubber emulsion. The prepared sponge has high tearing strength and tensile strength, and good foaming rate and elasticity; the prepared leather can be randomly prepared into the coating thickness, and the ageing resistance of the leather can be effectively improved.)

1. The high-temperature silicone rubber emulsion is characterized by comprising the following raw materials in parts by mass:

2. the high-temperature silicone rubber emulsion according to claim 1, wherein the silicone rubber is any one or more of methyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber and fluorine silicone rubber, and the viscosity of the silicone rubber is 2000-5000 pcs.

3. The high-temperature silicone rubber emulsion according to claim 1, wherein the oily emulsifier is any one or more of sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, oleic acid, fatty alcohol polyoxyethylene ether, glyceryl monostearate, polyether-modified silicone oil, and polyglycerol fatty acid ester.

4. The high-temperature silicone rubber emulsion according to claim 1, wherein the aqueous emulsifier is one or more selected from the group consisting of ammonium oleate, potassium oleate, triethanol alcohol, triethanol ammonium, aromatic polyethylene glycol-ethyl ether, polyether polysulfide, sodium alkyl sulfate, dibutyl naphthalene sulfonate, isobutyl naphthalene sulfonate, dioctyl sodium sulfosuccinate, sodium dodecyl sulfate, ethylene oxide adduct with fatty alcohol, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, fatty alcohol polyoxyethylene ether, glyceryl monostearate, polyether-modified silicone oil, and polyglycerin fatty acid ester.

5. The high-temperature silicone rubber emulsion according to any one of claims 1 to 4, wherein the pH regulator is any one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate; the mechanical stabilizer is one or more of potassium hydroxide, sodium hydroxide, potassium laurate, ammonium laurate, sodium vinylsulfonate, NN-methyl-N-oleoyl taurate, a condensate of ethylene oxide and fatty alcohol, and octyl phenyl polyoxyethylene ether.

6. A method for preparing a high-temperature silicone rubber emulsion as defined in any one of claims 1 to 5, comprising the steps of:

(1) adding an oily emulsifier into the silicone rubber, heating and uniformly stirring to obtain a silicone rubber crude emulsion;

(2) mixing an aqueous emulsifier, a pH regulator, a mechanical stabilizer and soft water, heating, adding the silicone rubber crude emulsion obtained in the step (1), and emulsifying to obtain an emulsion;

(3) standing the emulsified liquid obtained after the emulsification in the step (2) for a period of time, and filtering to obtain the high-temperature silicone rubber emulsion.

7. The preparation method according to claim 6, wherein in the step (1), the rotation speed of stirring is 300-500r/min, the stirring temperature is 70-85 ℃, and the stirring time is 20-40 min; in the step (2), the heating temperature is 70-85 ℃, and the emulsifying shearing speed is 5000-9000 r/min; in the step (3), the parking time is at least 24 h.

8. Use of the high-temperature silicone rubber emulsion according to any one of claims 1 to 5 or prepared by the preparation method according to claim 6 or 7 for preparing a sponge or leather.

9. The use according to claim 8, wherein the method for preparing the sponge by using the high-temperature silicone rubber emulsion comprises the following steps:

s1, putting 5-25 parts by weight of white carbon black, 0.8-2 parts by weight of benzoyl peroxide, 1-3.5 parts by weight of potassium oleate, 0.8-2.5 parts by weight of sodium dodecyl sulfate and 70-85 parts by weight of soft water into a stainless steel container, and stirring for 30-50min at the rotation speed of 300-500r/min to uniformly disperse to obtain a white carbon black/benzoyl peroxide composite dispersion;

s2, adding the white carbon black/benzoyl peroxide composite dispersion obtained in the step S1 into 200-300 parts by weight of the high-temperature silicone rubber emulsion, firstly stirring at the speed of 400-300 r/min for 15-40min for foaming, and then uniformly foaming at the speed of 150-300r/min for 8-15min to obtain a composite emulsion;

s3, injecting the composite emulsion in the step S2 into a mold with the temperature of 70-90 ℃, putting the mold into an oven with the temperature of 125-150 ℃ for sulfurization for 30-50min, taking out the obtained sponge product, cleaning with water, dehydrating, drying in the oven with the temperature of 125-150 ℃ and continuing to sulfurize for 30-50min to obtain the sponge product.

10. The use according to claim 8, wherein the process for preparing leather using the high temperature silicone rubber emulsion comprises the steps of:

SS1, putting 15-25 parts by weight of white carbon black, 0.8-2 parts by weight of benzoyl peroxide, 1-3.5 parts by weight of sodium dodecyl sulfate and 75-90 parts by weight of soft water into a stainless steel container, stirring for 25-50min under the condition that the rotating speed is 350-500r/min, and then uniformly dispersing to obtain a white carbon black/benzoyl peroxide composite dispersion;

SS2, adding the white carbon black/benzoyl peroxide composite dispersion obtained in the step SS1 into 200-300 parts by weight of the high-temperature silicone rubber emulsion, firstly stirring at the speed of 400-500r/min for 25-50min, standing for 16-32h for defoaming, and obtaining a composite emulsion;

SS3, spraying the composite emulsion obtained in the step SS2 on nylon fabric, drying in an oven at 75-85 ℃ for 45-60min, and then vulcanizing in an oven at 110-140 ℃ for 25-50min to obtain the leather.

Technical Field

The invention belongs to the technical field of silicone rubber processing, and particularly relates to a high-temperature silicone rubber emulsion, and a preparation method and application thereof.

Background

Silicone rubber refers to rubber having a backbone composed of alternating silicon and oxygen atoms, with the silicon atoms typically having two organic groups attached to them. The common silicon rubber mainly comprises silicon-oxygen chain links containing methyl and a small amount of vinyl, the introduction of phenyl can improve the high-temperature resistance and the low-temperature resistance of the silicon rubber, and the introduction of trifluoropropyl and cyano can improve the temperature resistance and the oil resistance of the silicon rubber. The silicon rubber has good low temperature resistance, can work at the temperature of-55 ℃ generally, and can reach-73 ℃ after phenyl is introduced. The silicon rubber has outstanding heat resistance, can work for a long time at 180 ℃, can still have elasticity for a plurality of weeks or more even at the temperature slightly higher than 200 ℃, and can instantaneously resist the high temperature of more than 300 ℃. Silicone rubber has good gas permeability, and oxygen transmission rate is the highest among synthetic polymers. In addition, the silicon rubber also has the outstanding characteristics of physiological inertia and no coagulation, so the silicon rubber is widely applied in the medical field.

The silicone rubber is classified into a heat vulcanization type (high temperature vulcanized silicone HTV) and a room temperature vulcanization type (RTV), wherein the room temperature vulcanization type is also classified into a polycondensation reaction type and an addition reaction type. The high-temperature silicon rubber is mainly used for manufacturing various silicon rubber products, and the room-temperature silicon rubber is mainly used as an adhesive, a potting material or a mold. The heat vulcanization type is the most used, and the heat vulcanization type is divided into methyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl vinyl phenyl silicone rubber PVMQ (low temperature resistant and radiation resistant), and other silicone rubber, fluorosilicone rubber and the like. The dosage of the methyl vinyl silicone rubber and the product grade are the most, and the dosage is the widest.

Because the main chain of the silicon rubber is formed by silicon-oxygen bonds (-Si-O-Si-) alternately, and the side chain is the structural characteristic of various organic groups, namely a semi-inorganic high molecular compound, the silicon rubber has excellent performances which can not be simultaneously possessed by a plurality of other materials, such as excellent high temperature resistance and low temperature resistance, excellent electrical insulation and chemical stability, good aging resistance, outstanding surface activity, hydrophobicity, moisture resistance, physiological inertia and the like. The organosilicon foam material combines the characteristics of organosilicon polymer and the characteristics of foam material, so that the organosilicon polymer has the excellent characteristics of the organosilicon polymer, has good physical characteristics of absorbing mechanical shock or impact and high-frequency shock absorption, and belongs to high-performance polymer soft foam material. Compared with common soft polyurethane foam (sponge), the organic silicon foam material has the advantages of no toxicity, high and low temperature resistance, moisture resistance, ultraviolet resistance, chemical corrosion resistance, aging resistance, no deformation and the like, so that the organic silicon foam material is more and more concerned by people.

The high-temperature silicone rubber has good physical and mechanical properties and thermal-oxidative aging resistance, and when used as foaming sponge, the high-temperature silicone rubber has high tensile strength and tear strength, but poor elasticity and low foaming rate. The high-temperature silicone rubber with better tensile strength and tearing strength is used for coating fabric as leather, the leather surface is smooth, the decontamination performance is good, and the fabric is waterproof, moistureproof, uvioresistant, chemical corrosion resistant, ageing resistant and non-deformable, is durable in use and has long service life; however, the high-temperature rubber compound has high viscosity, and is coated on fabrics, and the coating thickness is too thick, thin products are difficult to adjust, the uniformity is poor, and the application is not as limited as PU leather.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects and shortcomings in the background technology and providing the high-temperature silicone rubber emulsion with more excellent performance, and the preparation method and the application thereof.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the high-temperature silicone rubber emulsion comprises the following raw materials in parts by weight:

preferably, the silicone rubber is any one or more of methyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber and fluorine silicone rubber, and the viscosity of the silicone rubber is 2000-5000 pcs.

Preferably, the oily emulsifier is any one or more of sorbitan monolaurate (trade name span 20), sorbitan monopalmitate (trade name span 40), sorbitan monostearate (trade name span 60), sorbitan monooleate (trade name span 80), oleic acid, fatty alcohol polyoxyethylene ether, glyceryl monostearate, polyether modified silicone oil and polyglycerol fatty acid ester.

Preferably, the aqueous emulsifier is any one or more of ammonium oleate, potassium oleate, triethanol amine, triethanol ammonium, aromatic polyethylene glycol-ethyl ether, polyether polysulfide, sodium alkylsulfate, dibutyl naphthalene sulfonate, isobutyl naphthalene sulfonate, dioctyl sodium sulfosuccinate, sodium dodecyl sulfate, an adduct of ethylene oxide and fatty alcohol, polyoxyethylene sorbitan monolaurate (trade name tween 20), polyoxyethylene sorbitan monopalmitate (trade name tween 40), polyoxyethylene sorbitan monostearate (trade name tween 60), polyoxyethylene sorbitan monooleate (trade name tween 80), fatty alcohol polyoxyethylene ether, glyceryl monostearate, polyether modified silicone oil and polyglycerin fatty acid ester.

Preferably, the pH regulator is any one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.

Preferably, the mechanical stabilizer is any one or more of potassium hydroxide, sodium hydroxide, potassium laurate, ammonium laurate, sodium vinylsulfonate, sodium NN-methyl-N-oleoyl taurate, a condensate of ethylene oxide and fatty alcohol (peregal O) and octyl phenyl polyoxyethylene ether (trade name 65-03, also known as emulsifier OP-10).

Based on a general inventive concept, the present invention provides a preparation method of the above high temperature silicone rubber emulsion, comprising the following steps:

(1) adding an oily emulsifier into the silicone rubber, heating and uniformly stirring to obtain a silicone rubber crude emulsion;

(2) mixing an aqueous emulsifier, a pH regulator, a mechanical stabilizer and soft water, heating, adding the silicone rubber crude emulsion obtained in the step (1), and emulsifying to obtain an emulsion;

(3) standing the emulsified liquid obtained after the emulsification in the step (2) for a period of time, and filtering to obtain the high-temperature silicone rubber emulsion.

In the preparation method, preferably, in the step (1), the stirring speed is 300-500r/min, the stirring temperature is 70-85 ℃, and the stirring time is 20-40 min; in the step (2), the heating temperature is 70-85 ℃, and the emulsifying shearing speed is 5000-9000 r/min; in the step (3), the parking time is at least 24 h.

Based on a general inventive concept, the invention also provides an application of the high-temperature silicone rubber emulsion, and the high-temperature silicone rubber emulsion is used for preparing sponge or leather.

The method for preparing the sponge by adopting the high-temperature silicone rubber emulsion comprises the following steps:

s1, putting 5-25 parts by weight of white carbon black, 0.8-2 parts by weight of benzoyl peroxide, 1-3.5 parts by weight of potassium oleate, 0.8-2.5 parts by weight of sodium dodecyl sulfate and 70-85 parts by weight of soft water into a stainless steel container, and stirring for 30-50min at the rotation speed of 300-500r/min to uniformly disperse to obtain a white carbon black/benzoyl peroxide composite dispersion;

s2, adding the white carbon black/benzoyl peroxide composite dispersion obtained in the step S1 into 200-300 parts by weight of the high-temperature silicone rubber emulsion, firstly stirring at the speed of 400-300 r/min for 15-40min for foaming, and then uniformly foaming at the speed of 150-300r/min for 8-15min to obtain a composite emulsion;

s3, injecting the composite emulsion in the step S2 into a mold with the temperature of 70-90 ℃, putting the mold into an oven with the temperature of 125-150 ℃ for sulfurization for 30-50min, taking out the obtained sponge product, cleaning with water, dehydrating, drying in the oven with the temperature of 125-150 ℃ and continuing to sulfurize for 30-50min to obtain the sponge product.

The method for preparing leather by adopting the high-temperature silicone rubber emulsion comprises the following steps:

SS1, putting 15-25 parts by weight of white carbon black, 0.8-2 parts by weight of benzoyl peroxide, 1-3.5 parts by weight of sodium dodecyl sulfate and 75-90 parts by weight of soft water into a stainless steel container, stirring for 25-50min under the condition that the rotating speed is 350-500r/min, and then uniformly dispersing to obtain a white carbon black/benzoyl peroxide composite dispersion;

SS2, adding the white carbon black/benzoyl peroxide composite dispersion obtained in the step SS1 into 200-300 parts by weight of the high-temperature silicone rubber emulsion, firstly stirring at the speed of 400-500r/min for 25-50min, standing for 16-32h for defoaming, and obtaining a composite emulsion;

SS3, spraying the composite emulsion obtained in the step SS2 on nylon fabric, drying in an oven at 75-85 ℃ for 45-60min, and then vulcanizing in an oven at 110-140 ℃ for 25-50min to obtain the leather.

The emulsion preparation method has four emulsion modes:

(1) agent in water method: the emulsifier is added directly to water and oil is added under vigorous stirring to obtain oil-in-water (O/W) emulsion, which has coarse particles, uneven size and poor stability.

(2) Agent in oil method: the emulsifier is added directly to the oil, then the water and aqueous emulsifier are added together and then emulsified by mechanical high speed shearing. The emulsion obtained by the method is uniform, the particle size is consistent, and the particle diameter is about 0.5 mu m, which is the most stable method. However, the required amount of the emulsifier is large, and after the emulsifier is added into the latex, the forming process of the latex and the physical and mechanical properties of the latex are influenced.

(3) The alternate flow liquid adding method comprises the following steps: the two liquids are added in small amounts by turns. The method is complex to operate, low in efficiency and poor in stability.

(4) The primary soap method comprises the following steps: dissolving fatty acid in oil, dissolving alkali solution in water, and contacting at interface of two phases to obtain soap, or obtain stable emulsion. When emulsifying by the nascent soap method, the fatty acid and the alkali are heated to 70-85 ℃ before emulsification, and when the fatty acid and the alkali are mixed at high speed, the soap emulsifier can be quickly reacted and generated in situ, the coarse emulsion of the silane coupling agent is emulsified into fine emulsion, the stability and the emulsification effect of the emulsion are improved, and the using amount of the emulsifier is reduced. Such as oleic acid/triethanolamine to form triethanolamine oleate; oleic acid/potassium hydroxide produced potassium oleate.

According to the characteristics of large molecular weight and difficult emulsification of the high-temperature silicone rubber, the invention adopts a nascent soap method to emulsify the high-temperature silicone rubber.

The stability of the emulsion is related to the strength of the interfacial film, the interfacial film generated by a single surfactant is not compact, the mechanical strength is not high, the emulsion is easy to crack and unstable, and after the emulsifier with a large HLB value difference is compounded, hydrophilic groups of the water-soluble surfactant, such as polyoxyethylene groups, have strong interaction with a water phase, and the groups are deeper into the water phase, so that hydrophobic groups of two surface active compounds are more closely arranged in the interfacial film, thereby generating a synergistic effect, improving the mechanical strength of the interfacial film and stabilizing the emulsion. For example, the high-temperature silicone rubber can be well emulsified by the combination of oleic acid with the HLB value of 1.0, span 80 with the HLB value of 4.3 and potassium oleate with the HLB value of 20.0 (generated by the reaction of the oleic acid and the potassium hydroxide), and the combination of span 80 with the HLB value of 4.3, sodium dodecyl sulfate with the HLB value of 10.638 and Tween 40 with the HLB value of 15.6.

In addition, because emulsification requires continuous stirring, mechanical power can destroy the stability of the emulsion, and a proper mechanical stabilizer needs to be added into the emulsification formula; the emulsion has high viscosity, which is not beneficial to emulsification and storage, and the pH value regulator such as potassium hydroxide can improve the pH value of the emulsion, reduce the viscosity and further improve the stability of the emulsion.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention heats and mixes silicon rubber and oil emulsifier evenly, then adds into water phase containing water emulsifier, emulsifies into homogeneous high temperature silicon rubber latex under certain speed, temperature and time, uses the high temperature silicon rubber latex to make sponge, the tearing strength and tensile strength are high, the foaming rate and elasticity are good, also can be used to make big and thick latex products such as pillow, mattress, cushion, etc. that can't be produced by dry glue, the automaticity and production efficiency are high.

2. After the silicone rubber is prepared into the high-temperature silicone rubber emulsion, the viscosity of the silicone rubber is greatly reduced, the range of coating thin products is expanded, the reliability and efficiency of the coating process are effectively improved, and the thickness uniformity and quality stability of the coated fabric are improved; the high-temperature silicone rubber emulsion coated fabric is used as leather instead of PU (polyurethane), the coating thickness can be prepared at will, the anti-aging performance of the leather can be effectively improved, the phenomena of peeling and chipping of the PU leather caused by long service life are greatly improved, and meanwhile, the leather surface is smooth, has good decontamination performance, is waterproof, moistureproof, uvioresistant, anti-chemical corrosion, anti-aging and non-deforming, is durable and has long service life; therefore, the development of the high-temperature silicone rubber emulsion can expand the application field of the high-temperature silicone rubber and promote the progress of the silicone rubber technology.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail with reference to the preferred embodiments, but the scope of the invention is not limited to the specific embodiments described below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.