阅读说明：本技术 一种中端羧基改性sbr橡胶及其制备方法和在环氧树脂胶粘剂或硫化橡胶制品中的应用 (Middle-end carboxyl modified SBR (styrene butadiene rubber) rubber, preparation method thereof and application thereof in epoxy resin adhesive or vulcanized rubber product ) 是由 张建国 任诚 蒋文英 姚琼 于 2018-06-13 设计创作，主要内容包括：本发明公开了一种中端羧基改性SBR橡胶及其制备方法和在环氧树脂胶粘剂或硫化橡胶制品中的应用,中端羧基改性SBR橡胶的制备方法是将阴离子聚合溶聚丁苯无规共聚物胶液与顺丁烯二酸酐通过过氧化物引发进行Diels-Alder反应,所得反应产物经过水解凝聚,即得；所得中端羧基改性SBR橡胶应用于改性环氧树脂胶粘剂,其与环氧树脂具有良好的相容性,能改善环氧树脂与活性极性填充料之间的亲和力,可以作为高弹和高韧性的结构型粘合剂使用,也可用硫硫化制成与极性材料相粘的橡胶制品。(The invention discloses a middle-end carboxyl modified SBR rubber and a preparation method thereof and application thereof in epoxy resin adhesives or vulcanized rubber products, wherein the preparation method of the middle-end carboxyl modified SBR rubber is that anion polymerization solution polymerized styrene-butadiene random copolymer glue solution and maleic anhydride are initiated by peroxide to carry out Diels-Alder reaction, and the obtained reaction product is obtained by hydrolytic condensation; the obtained middle-end carboxyl modified SBR rubber is applied to a modified epoxy resin adhesive, has good compatibility with epoxy resin, can improve the affinity between the epoxy resin and active polar filler, can be used as a high-elasticity and high-toughness structural adhesive, and can also be vulcanized by sulfur to prepare a rubber product adhered with a polar material.)

1. A preparation method of middle-end carboxyl modified SBR rubber is characterized by comprising the following steps: and (3) carrying out Diels-Alder reaction on the anion polymerization solution polymerized styrene-butadiene random copolymer glue solution and maleic anhydride through peroxide initiation, and carrying out hydrolytic condensation on the obtained reaction product to obtain the medium-end carboxyl modified SBR rubber.

2. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 1, wherein: the mass of the maleic anhydride is 3-8% of the total mass of butadiene blocks in the anion polymerization solution-polymerized butadiene-styrene random copolymer.

3. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 1, wherein: the peroxide comprises at least one of benzoyl peroxide, azodiisobutyronitrile and cumyl peroxide.

4. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 1, wherein: the mass of the peroxide is 0.1-0.5% of that of the anion polymerization solution polymerized butylbenzene random copolymer.

5. The method for preparing a middle-end carboxyl modified SBR rubber according to any one of claims 1 to 4, wherein: the Diels-Alder reaction is carried out at the temperature of 50-90 ℃ for 2-3 h.

6. The method for preparing a middle-end carboxyl modified SBR rubber according to any one of claims 1 to 4, wherein: the anionic polymerization solution polymerized butadiene-styrene random copolymer glue solution is prepared by anionic polymerization of styrene and butadiene polymerization monomers and a divinylbenzene chain extender.

7. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 6, wherein: the mass ratio of styrene to butadiene is (20-30) to (80-70).

8. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 6, wherein: the mass ratio of the divinyl benzene chain extender to the total mass of the styrene and butadiene polymerized monomers is 1: 1400-3000.

9. The method for preparing the middle-end carboxyl modified SBR rubber according to claim 6, wherein: the number average molecular weight of the butylbenzene random copolymer in the anion polymerization solution polymerized butylbenzene random copolymer glue solution is 8 multiplied by 10⁴～10×10⁴。

10. The middle-end carboxyl modified SBR rubber is characterized in that: prepared by the method of any one of claims 1 to 9.

11. The use of a medium carboxyl end modified SBR rubber as claimed in claim 10, wherein: the modified epoxy resin adhesive is applied to modified epoxy resin adhesives.

12. The use of a medium end carboxyl modified SBR rubber as claimed in claim 11, wherein: the middle-end carboxyl modified SSBR rubber is combined with epoxy resin to be used as a bonding material of a bonding type vibration damping material, a bonding type drying material or a bonding type damping material.

13. The use of a medium carboxyl end modified SBR rubber as claimed in claim 10, wherein: the method is applied to vulcanized rubber products.

Technical Field

The invention relates to a modified SBR rubber, in particular to a middle-end carboxyl modified SBR rubber, and also relates to an application of the middle-end carboxyl modified SBR rubber as a cross-linking agent in an epoxy resin adhesive or a vulcanized rubber product, belonging to the technical field of adhesives.

Background

Conventional emulsion polymerized styrene-butadiene rubbers such as SBR1500 or SBR1502 and anionically polymerized conventional SSBR have no reactive functional groups in their molecular structure and thus cannot be cross-linked with epoxy resins or other reactive group-containing resins to produce adhesives. The existing SBR 1006 molecular structure is combined with organic acid, but the polymer is obtained by adopting an emulsion high-temperature thermal polymerization method, the content of the combined styrene in the polymer molecule is not more than 24 wt% at most, and the polymer also contains free organic acid and soap, so that the crosslinking density and strength of the epoxy resin are reduced, and the monomer conversion rate is not higher than 85% during polymerization. In addition, the conventional styrene butadiene rubber SBR1500, SBR1502 and the like and general SSBR have no active functional group in the molecular structure, and cannot be subjected to a crosslinking reaction with active resin such as epoxy resin to prepare an adhesive for bonding polar materials such as aluminum materials, steel materials, ceramics and the like.

Thermal polymerization SBR 1006Elastomer from LION ELASTOMERS, USA, with a bound styrene content of 22.5-24.5% and an organic acid content of 4-6% by weight. The polymer is prepared by heating emulsifier, fatty acid soap, initiator, regulating assistant and styrene-butadiene-conjugated organic acid in water solution at high temperature, emulsifying, forming, acidifying with acid to obtain sodium fatty acid solution, emulsifying and polymerizing to obtain gel solution with acid as chelating agent, and final obtaining raw gel with density of 0.94 and soap content not higher than 0.5%. The molecular weight distribution of the raw rubber is wide, and the raw rubber is easy to melt and fill with inorganic filler with high proportion. Household goods, gaskets, adhesives, mechanical rubber products, floor rubber pads, coatings and adhesives for machines such as automobile friction brakes, brakes for braking systems can be used. However, the raw polymer rubber contains soap and free fatty acid, and particularly, the free fatty acid can carry out end capping reaction with epoxy groups in application such as epoxy resin, so that the cross-linking density of the epoxy resin is influenced. In addition, the preparation method of SBR 1006Elastomer is not reported in the literature.

Chinese patent (CN1544522) discloses a preparation method of high benzene rubber, which takes RCOOMe and the like as an emulsifier, peroxide as an initiator, mercaptan as a regulator and the like to copolymerize 5-25% of butadiene and 75-95% of styrene emulsion at the temperature of 40-80 ℃, and prepares high benzene resin under the condition that the conversion rate is more than 98.5% within 5-12 h; then the synthesized high benzene resin emulsion is mixed and co-coagulated with SBR-1502 latex or SBR-1500 latex. However, the emulsion polymerized styrene-butadiene rubber with high styrene content is mainly used as a tire material, and the molecular structure does not contain functional groups, so that the emulsion polymerized styrene-butadiene rubber cannot be subjected to crosslinking reaction with other materials such as epoxy resin and the like to prepare an adhesive. Chinese patent (CN105449142A) discloses a carboxyl-containing polyimide/nano-silica composite porous film and a preparation method thereof. The preparation method comprises the steps of firstly preparing soluble polyimide containing a carboxyl structure, and utilizing the strong hydrogen bonding action of a large number of hydroxyl functional groups on the surface of nano silicon dioxide and carboxyl functional groups in the polyimide structure to realize the uniform dispersion of nano silicon dioxide particles in polyimide high polymer solution, but the material does not belong to an elastic material and can not be used as an adhesive. Chinese patent (CN104877409A) discloses a heat-resistant anticorrosive maleic anhydride grafted SBS modified asphalt waterproof coiled material and a preparation method thereof, the composite asphalt material is obtained by maleic anhydride grafted SBS modified matrix asphalt, and raw materials such as blast furnace slag micro powder, nano metal chromium powder and the like are mixed in the composite asphalt material, but the modified SBS belongs to thermoplastic elastomer, has extremely narrow molecular weight distribution, is reflected in poor processability, cannot be uniformly mixed by an internal mixer, and is difficult to be mixed with epoxy resin. In addition, Chinese patent (CN105111995A) discloses a maleic anhydride grafted styrene block copolymer blended modified polyurethane hot melt adhesive and a preparation method thereof. ("Synthesis of styrene-maleic anhydride alternating copolymer by solution polymerization", Tang-xu-chemical, 2010-03) discloses that a styrene-maleic anhydride copolymer is synthesized by a solution polymerization method by using butanone as a solvent under the initiation of Benzoyl Peroxide (BPO), but the polymer belongs to thermoplastic resin and is a rigid material. (preparation and structure and performance of maleic anhydride styrene-butadiene-styrene block copolymer ionomer, Liuda Steel, Seichong spring, etc., synthetic rubber industry, 2009, 04) discloses that the preparation conditions of maleic anhydride styrene-butadiene-styrene block copolymer (SBS) are examined in a toluene/cyclohexane mixed solvent system to obtain ideal reaction conditions of 30/100/1 mass ratio of maleic anhydride/SBS/benzoyl peroxide, 0.10g/mL mass concentration of SBS, 10min dropping time of benzoyl peroxide/toluene priming solution and 4h reaction at 75 ℃. Under the condition, higher grafting rate (6.87%) can be obtained. The obtained maleic anhydride SBS is neutralized by sodium hydroxide solution to generate sodium ionomer, and the tensile strength, lap shear strength and emulsifying property of the ionomer are all improved along with the increase of the maleic anhydride degree. The purpose of the SBS ionomer is to improve the strength of the original SBS, but the ionomer contains no active sites which are blocked by sodium, and the ionomer can not be used as an adhesive in the same way.

Disclosure of Invention

In view of the drawbacks of the prior art, a first object of the present invention is to provide a novel monomodal styrene-butadiene random copolymer having a broad molecular weight distribution and a randomly distributed organic acid at the middle end of the molecule.

The second purpose of the invention is to provide a simple and low-cost method for synthesizing the medium-terminal carboxyl modified SBR rubber.

The third objective of the present invention is to provide an application of the middle carboxyl-terminated modified solution polymerized styrene-butadiene rubber in an epoxy resin adhesive, wherein the middle carboxyl-terminated modified solution polymerized styrene-butadiene rubber and the epoxy resin are used as a styrene-butadiene rubber-epoxy resin adhesive, and the middle carboxyl-terminated modified solution polymerized styrene-butadiene rubber strengthens the affinity between the rubber and active polar fillers (such as white carbon black, calcium carbonate, barium sulfate, etc.), has good compatibility with the strong polar epoxy resin, and can be used as a high-elasticity and high-toughness structural adhesive.

The fourth purpose of the invention is to provide an application of the middle carboxyl-terminated modified solution-polymerized styrene-butadiene rubber in vulcanized rubber products, wherein the affinity of the rubber obtained by vulcanizing the middle carboxyl-terminated modified solution-polymerized styrene-butadiene rubber to polar materials is enhanced, and the middle carboxyl-terminated modified solution-polymerized styrene-butadiene rubber is particularly suitable for preparing rubber products bonded with the polar materials.

In order to realize the technical purpose, the invention provides a preparation method of middle-end carboxyl modified SBR rubber, which comprises the steps of carrying out Diels-Alder reaction on anion polymerization solution polymerized styrene-butadiene random copolymer glue solution and maleic anhydride through peroxide initiation, and condensing the obtained reaction product through water vapor to obtain the middle-end carboxyl modified SBR rubber.

In a preferred scheme, the mass of the maleic anhydride is 3-8% of the total mass of butadiene blocks in the anion polymerization solution-polymerized butadiene-styrene random copolymer.

In a preferred embodiment, the peroxide includes benzoyl peroxide and/or azobisisobutyronitrile and/or cumene peroxide.

In a preferred embodiment, the mass of the peroxide is 0.1-0.5% of the mass of the anionic polymerized solution-polymerized styrene-butadiene random copolymer.

In the preferable scheme, the Diels-Alder reaction is carried out at the temperature of 50-90 ℃ for 2-3 h. The preferable reaction temperature is 60 to 80 ℃. Under the optimized condition, the Diels-Alder reaction conversion rate of the anion polymerization solution polymerized butadiene-styrene random copolymer glue solution and maleic anhydride reaches 100 percent, and the butadiene anhydride is completely converted.

In a preferred embodiment, the solution of the anion-polymerized solution-polymerized butylbenzene random copolymer is obtained by anion polymerization of styrene and butadiene polymerized monomers and a divinylbenzene chain extender.

Preferably, the mass ratio of the styrene to the butadiene is (20-30) to (80-70).

Preferably, the mass ratio of the divinyl benzene chain extender to the total mass of the styrene and butadiene polymerized monomers is 1: 1400-3000. And Divinylbenzene (DVB) is directly added to the polymerization reactor in one portion for copolymerization after being mixed with styrene and butadiene.

Preferably, the number average molecular weight Mn of the butylbenzene random copolymer in the anion polymerization solution polymerized butylbenzene random copolymer glue solution is 8 multiplied by 10⁴～10×10⁴Weight average molecular weight Mw of 12X 10⁴～20×10⁴. The Mw/Mn is preferably 1.5 to 1.7.

The Mooney viscosity of the solution of the anionic polymerization solution polymerized styrene-butadiene random copolymer rubber is 50-70.

The invention also provides the medium-end carboxyl modified SBR rubber prepared by the method.

The invention also provides application of the middle-end carboxyl modified SBR rubber, which is applied to the modified epoxy resin adhesive.

Preferably, the medium-end carboxyl modified SBR rubber is combined with epoxy resin to be used as a bonding material of a bonding type vibration damping material, a bonding type drying material or a bonding type damping material.

The invention also provides application of the middle-end carboxyl modified SBR rubber, and the middle-end carboxyl modified SBR rubber is applied to vulcanized rubber products.

The anion polymerization solution polymerized butylbenzene random copolymer glue solution is obtained by adopting the conventional anion polymerization method in the prior art. In the anionic polymerization process, common tetrahydrofuran is adopted as an activating agent, wherein the concentration of proper THF in a polymerization solvent is 20-80 mg/Kg, and the vinyl content of a polybutadiene block in the synthesized solution-polymerized styrene-butadiene rubber raw rubber is less than 20% (without using an efficient adjusting activating agent such as ETE and the like and having high vinyl content to reduce the cost). The terminating agent used in the anionic polymerization reaction can be common monochlorotrimethylsilane with the dosage of butyllithium/monochlorotrimethylsilane being 1/1-1.2 (mol ratio), which aims to convert the polymerization glue solution into neutrality and avoid the reaction of alkaline lithium and acid anhydride to generate soap. The anionic polymerization is carried out under the well-known conditions, such as the reaction temperature is 40-90 ℃, the reaction pressure is 0.3-0.5 MPa, and the polymerization time is 30-50 min; the reaction termination temperature is 50-70 ℃, the termination time is 15min, and the glue solution concentration is 10-15 wt%. The SSBR crude rubber obtained in the anionic polymerization reaction process has the styrene content of 20-30 percent and the diene monomer conversion rate of 100 percent.

In the addition reaction of the anion polymerization solution polymerized styrene-butadiene random copolymer glue solution (namely SBR virgin glue) and maleic anhydride: when the dosage of the maleic anhydride in the total monomers is too low, namely the equivalent of the combined carboxyl is too low, the curing crosslinking point is too low; when the amount of maleic anhydride used in the total monomers is too high, the equivalent of the carboxyl groups bound is too high, and the SBR glue solution is gelled. Therefore, the mass consumption of the appropriate maleic anhydride is 4-8 wt% of the total butadiene consumption. The initiator can be selected from substances which can generate free radicals, such as benzoyl peroxide, azodiisobutyronitrile, cumene peroxide and the like, and the dosage of the initiator is 0.1-0.5 wt% of the total monomer dosage.

The invention adopts SSBR virgin rubber synthesized by anionic polymerization to carry out maleic anhydride middle-end addition for the first time to obtain the middle-end carboxyl modified SBR. The medium-end carboxyl modified SBR and the epoxy resin are used together for a structural adhesive with high elasticity and high toughness and are used as damping, dryness-reducing and damping materials: the SBR without carboxyl has no adhesive property with metal materials after being vulcanized by sulfur, and the (-COOH) carboxyl in the SBR with carboxyl is easy to be subjected to ring-opening crosslinking with epoxy groups in epoxy resin to show good adhesive property with the metal materials. Meanwhile, the rubber containing carboxyl at the middle terminal of the SBR molecular chain can also be used for preparing corresponding rubber products by adopting the traditional sulfur vulcanization, and the bonding capability between the vulcanized rubber and polar materials can be obviously changed.

The bonding type vibration damping, dryness reducing or damping material is a common material in the prior art, epoxy resin is generally used as an adhesive, the technical scheme of the invention adopts middle carboxyl modified SBR as a modifier to be matched with epoxy resin to be used as a modified epoxy resin adhesive, and the modified epoxy resin adhesive is suitable for the common bonding type vibration damping, dryness reducing or damping material. The bonding type vibration-damping, drying-reducing and damping rubber material comprises middle-end carboxyl modified SBR, epoxy resin and other well-known conventional raw materials, such as rubber filling oil, a plasticizer, material, filling material, a well-known universal accelerator, sulfur and other auxiliaries. The epoxy resin used in the present invention may be commercially available liquid epoxy resins, such as CYD-128, E-44 and E-51. The filling materials used are silica, carbon black, alumina powder, iron powder and the like which are well known in the industry.

The middle-end carboxyl modified SBR is mixed with fillers such as epoxy resin, white carbon black and the like, softeners, auxiliaries well known in the industry and the like, after vulcanization and crosslinking, the elongation at break is as high as 200%, the permanent deformation is less than 50%, the hardness (Share A) is 80-90, and the shear strength after lapping and bonding of 45# steel and 45# steel is greater than 12 MPa. The rubber has excellent rubber elasticity and adhesive property to metal materials, and aims to maximally show the original properties of the respective materials. It is especially suitable for cement floor, metal surface and lining to reach the aims of anticorrosion, vibration damping, dryness reducing and damping.

The adhesive type vibration damping, dryness reducing or damping rubber material disclosed by the invention has the following preferable formula (in parts by mass): the modified SSBR 160 with middle terminal carboxyl, the epoxy resin is quantified by epoxy value, 100 inorganic filler, 8 pigment, 30 environment-friendly rubber oil, 8 plasticizer, 4.5 zinc oxide, 40202.5 anti-aging agent, 3.2 accelerator TBBS and 2.3 sulfur. Among them, the epoxy resin is preferably an epoxy resin species having an equivalent number of epoxy groups in the middle-end carboxyl group-modified SBR, or a carboxyl group/epoxy group ratio of 1/1 (molar ratio); a preferred epoxy resin is CYD-128 or a corresponding epoxy resin such as E-44 or E-51. If the inorganic filler is used for preparing light-colored products, white carbon black, aluminum oxide and the like can be selected, and simultaneously, materials or colors of dyes which are correspondingly designed are selected; if a black product is prepared, the inorganic filler is necessary to be filled, and carbon black is added for dyeing. The environment-friendly rubber oil is preferably at least one of TDAE or rubber oil obtained by hydrogenating and decoloring heavy aromatic oil such as NAP-10, naphthenic oil, white oil and the like. The plasticizer is preferably at least one of dibutyl phthalate, dioctyl phthalate or dibutyl adipate, and is mainly used for plasticizing hard segments of the cured epoxy resin. The pigment is preferably at least one of carbon black, ultramarine, iron red, or the like, as required.

The mixing method of the middle-end carboxyl modified SBR rubber compound can be completed by utilizing the existing mature mixing process. The mixing operation method comprises the following steps: the preparation method comprises the steps of firstly putting the middle-end carboxyl modified SBR, epoxy resin, rubber oil, a plasticizer, a filler, materials, zinc oxide, an anti-aging agent, an accelerator and the like into an internal mixer or an open mill, mixing for 6min at room temperature to 120 ℃, finishing master batch, putting the master batch on a water-cooled open mill, adding sulfur after the master batch is coated on a roller with the roller spacing of 1.5mm and the roller temperature of 50-60 ℃, cutting the roller after the sulfur is dispersed, making 3/4 cutting knives for three times at intervals of 15s, adjusting the roller spacing to 0.8mm, rolling the mixed batch, alternately passing through each end longitudinally for six times, and pressing the rubber material into a rubber sheet with the thickness of about 2.2 mm. The invention discloses a preparation and a test of a basic performance sample of a middle-end carboxyl modified SBR compound: and vulcanizing the sample on a flat vulcanizing machine, wherein the vulcanizing temperature is 145-160 ℃, and the vulcanizing time is 15-20 min. Shear strength test of the rubber compound bonded steel sheet: the mixed rubber sheet is added between two pieces of 45# steel with the thickness of 25 multiplied by 100 multiplied by 2mm, and is vulcanized and crosslinked to prepare a sample under the pressure of 2MPa, the temperature of 145-160 ℃ and the time of 15-20 min, and the test is carried out according to the test method of the strength performance of the shear adhesive under the tension load of CSN 668510-1960 (metal to metal). And (4) analyzing the physical properties of the molded vulcanized rubber.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

the molecular chain middle-end carboxyl modified SSBR has a relatively suitable branched molecular long chain, a molecular weight distribution index and wide grades, polar carboxyl is uniformly distributed in the molecular chain, and the SSBR has excellent affinity with polar fillers such as silicon dioxide powder, calcium carbonate powder and barium sulfate powder, and is particularly important for the unit operation process of mixing and subsequent processing of a composite sizing material.

The SBR glue solution synthesized by the anionic solution polymerization method is subjected to addition reaction in solution by using maleic anhydride, the grafting efficiency can be 100 percent converted, the content of combined carboxyl is proper, compared with maleic anhydride dry grafting SBS, the maleic anhydride solution grafting technology does not contain free maleic anhydride, and simultaneously compared with emulsion method, the maleic anhydride grafting reaction time is short, the conversion rate is high, the reaction can be carried out quantitatively, and the method belongs to homogeneous grafting reaction.

The modified SBR with terminal carboxyl in molecular chain is easy to mix with epoxy resin, the double bond in the mixed rubber can be vulcanized under the action of sulfur, the carboxyl in the molecule can also be ring-opened and cross-linked with the epoxy group in the epoxy resin, the vulcanized and cross-linked elastomer has good elasticity and adhesive force to polar materials such as cement, metal and the like, can be widely used for vibration damping, drying reduction and damping of automobiles, stations and airport ground decoration, military equipment, and can also be used for home decoration, industrial backing plate gaskets and the like. The product can also show excellent anti-aging performance, which is not possessed by general SBR, BR and other rubber seeds.

The preparation process of the molecular chain middle-terminal carboxyl modified SBR belongs to homogeneous reaction, is simple to prepare, can be synthesized by utilizing the existing mature process, is easy to control the reaction and is easy to industrialize.

Detailed Description

The present invention is illustrated by the following examples, which are not intended to limit the scope or practice of the invention.

And (3) measuring the carboxyl content in the middle-end maleic anhydride modified SBR molecule by adopting an acid-base titration method.

The physical properties of the vulcanised-cross-linked rubber and the shear strength of the adhesive sample were determined using an INSTRON tensile machine.