阅读说明：本技术 一种基于部分氢化聚苯乙烯-b-共轭二烯/二乙烯苯无规共聚物的密封条材料及其制备 (Sealing strip material based on partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer and preparation thereof ) 是由 张颖 蒋文英 张建国 朱建军 于 2019-03-20 设计创作，主要内容包括：本发明公开了一种基于部分氢化聚苯乙烯-b-共轭二烯/二乙烯苯无规共聚物的密封条材料及其制备方法,密封条材料包括部分氢化聚苯乙烯-b-共轭二烯/二乙烯苯无规共聚物、硫黄及补强剂、填充剂、填充油、偶联剂、促进剂、后效性硫化剂和氧化锌、硬脂酸和防老剂等辅料。该配方通过混炼、挤压、硫化可以获得物理机械性能好、抗老化性强、耐热性能好、压缩变形低、持续抗张和抗疲劳时间长的密封条,特别适合户外窗使用。(The invention discloses a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer and a preparation method thereof. The sealing strip with good physical and mechanical properties, strong aging resistance, good heat resistance, low compression deformation, long lasting tensile and fatigue resistance time can be obtained by mixing, extruding and vulcanizing the formula, and is particularly suitable for outdoor windows.)

1. A sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer, characterized in that: comprises partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer, sulfur and auxiliary materials;

the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer is obtained by partially hydrogenating a copolymer with a structure shown in a formula 1:

S-b-(I/B-D)

formula 1

Wherein the content of the first and second substances,

s is a styrene homopolymerization block, and I/B-D is a conjugated diene and divinyl benzene random copolymerization block; the conjugated diene comprises butadiene and/or isoprene;

the ratio of the mass of styrene units to the mass of conjugated diene units in the copolymer having the structure of formula 1 is (20 to 40)/(80 to 60), and the mass of divinylbenzene units is 0.08 to 0.16% of the total mass of conjugated diene units.

2. The sealant strip material according to claim 1, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the number average molecular weight of the copolymer with the structure of the formula 1 is in the range of 100000-150000, the molecular weight distribution index is 2.0-5.0, and the branching distribution index is 1-8.

3. The sealant strip material according to claim 1, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the number average molecular weight of the styrene homopolymerization block is in the range of 15000-35000.

4. The sealant strip material according to claim 1, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the proportion of 1, 4-addition quantity in the isoprene unit in the conjugated diene and divinylbenzene random copolymerization block is more than 85 percent; the proportion of 1, 2-addition amount in the butadiene unit is more than 20%.

5. The sealant strip material according to claim 1, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the total iodine value of the butadiene unit and the isoprene unit of the conjugated diene and divinylbenzene binary random copolymer block after partial hydrogenation is 8-30 g/100g of rubber.

6. The sealant strip material according to claim 1, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the auxiliary materials comprise a reinforcing agent, a filling agent, filling oil, a coupling agent, an accelerator, a post-effective vulcanizing agent, zinc oxide, stearic acid and an anti-aging agent.

7. The sealant strip material according to claim 6, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer:

the reinforcing agent comprises carbon black and/or white carbon black;

the filler comprises at least one of heavy calcium carbonate, barium carbonate, light calcium carbonate, precipitated barium sulfate and talcum powder;

the extender oil comprises a mineral white oil;

the coupling agent comprises a siloxane coupling agent;

the accelerator comprises at least one of a vulcanization accelerator DTDC, a vulcanization accelerator TBzTD, a vulcanization accelerator TBSI, a vulcanization accelerator TMTD and a vulcanization accelerator D;

the anti-aging agent comprises phenol and/or organic amine antioxidant;

the post-cure vulcanizing agent comprises ZXK-HTS.

8. A sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer according to any one of claims 1 to 6, wherein: the adhesive comprises the following components in parts by mass:

100 parts of partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer;

120-140 parts of carbon black;

80-100 parts of calcium carbonate;

70-90 parts of filling oil;

7-10 parts of a coupling agent;

3-5 parts of an anti-aging agent;

3-6 parts of an accelerator;

1.5-2.5 parts of an after-effect vulcanizing agent;

4-5 parts of zinc oxide;

1-2 parts of stearic acid;

0.5-2 parts of sulfur.

9. The sealant strip material according to claim 8, wherein the sealant strip material comprises a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer: the accelerant consists of the following components in parts by mass:

1.0-1.5 parts of a vulcanization accelerator DTDC;

0.5-1.0 part of vulcanization accelerator TBzTD;

0.5-1.0 part of vulcanization accelerator TBSI;

1.0-1.5 parts of a vulcanization accelerator TMTD;

0.5-1.0 part of vulcanization accelerator D.

10. The method for preparing a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer as claimed in any one of claims 1 to 9, wherein: mixing the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer and auxiliary materials for the first time to obtain mixed rubber, and mixing the mixed rubber and sulfur for the second time to obtain master batch; and (3) tabletting, layering, extruding, molding and vulcanizing the master batch to obtain the rubber.

11. The method for preparing a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer according to claim 10, wherein the method comprises the following steps: the first-stage mixing temperature is 145-150 ℃, and the mixing time is 200-280 s.

12. The process for producing a seal bar material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer according to claim 10, wherein: the two-stage mixing temperature is 145-150 ℃, and the mixing time is 80-100 s.

13. The method for preparing a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer according to claim 10, wherein the method comprises the following steps: the molding conditions in the extrusion molding process are as follows: the length-diameter ratio L/D of the screw is 15-16, the temperature of the inlet area of the screw is set to be room temperature, the temperature of the preheating area is 90-110 ℃, and the temperature of the forming die head is set to be 130-140 ℃; the linear extrusion speed is 0.8-5 m/min, and the vacuum degree (0.01-0.1) is 101.325 KPa.

14. The method for preparing a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer according to claim 10, wherein the method comprises the following steps: the vulcanization conditions are as follows: the vulcanization temperature is 90-180 ℃, and the vulcanization time is 8-15 min.

Technical Field

The invention relates to a sealing material and a preparation method thereof, in particular to a sealing strip material obtained by taking a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer containing partial double bonds, long chain branching and wide molecular weight distribution as an elastomer, belonging to the technical field of sealing materials.

Background

The traditional hydrogenated polystyrene-conjugated diene copolymer is a polymer initiated by butyl lithium in the presence of a solvent and directionally polymerized by styrene and conjugated diene, and the molecular structure of the copolymer can be linear or star-shaped, and the copolymer is mainly used for thermoplastic elastomers and other plastic materials. For example, patent ZL97108078.4, USP4980421(1990), EP0471415 (1991), USP5132372(1992), USP5206307(1993) and the like describe elastomers prepared by hydrogenating block type polystyrene-conjugated diene polymers, the preparation of such hydrogenated elastomers or copolymers is carried out by complete hydrogenation, the double bonds in the conjugated diene units in the hydrogenated polymers are completely hydrogenated, no double bonds are present in the polymer molecules, and thus the hydrogenated polymers cannot be processed and vulcanized by using a sulfur-accelerator system or under the action of peroxide, and the products obtained by blending and extruding the completely hydrogenated polystyrene-conjugated diene block polymers with polyolefins (PP) exhibit the behavior of thermoplastic elastomers, and are unsuitable for use as sealing strip materials due to large compression set and permanent set. The reason for this is that the interface between PP and SEBS molecules is phase-separated, and the PP and SEBS phase planes are peeled off and broken under the action of a long stress. For example, SEBS-602 and SEBS-604 which are produced by China petrochemical company, Balng petrochemical company, synthetic rubber industry and have the hydrogenation degree of more than 98 percent and are mixed with rib agents such as polypropylene PP, white oil, calcium carbonate and the like for granulation to prepare the special material for the sealing strip, the composite material has the hardness of 70-88A, the 300 percent stress at definite elongation of 6-8MPa, the elongation at break of 450 percent, the permanent deformation of 50 percent and the continuous tensile time of less than 72 hours. In addition, research shows that although the existing commercial products of YH series and series of SEBS and SEPS of Kraton company have good processing and extrusion molding properties, the products have large material deformation, poor compatibility with softening oil, no double bonds in polymer molecules, narrow molecular weight distribution and large polymer cohesion, cannot be molded by the mixing and vulcanization modes commonly used by synthetic rubber, cannot be vulcanized by sulfur, and the injection molded products are physically crosslinked, have low strength, large deformation, poor continuous tensile fatigue resistance and poor aging resistance, and are not suitable for sealing strip materials used under high temperature and strong sunlight.

However, although the molecules of the traditional polymers such as BR, ESBR, NR, SSBR and SIBR contain a large amount of unsaturated double bond units, the crude rubber strength, melt elasticity or melt strength of the polymers are relatively low, and the crude rubber behavior of the elastomer is not achieved; the appearance of the product is blocky, the stiffness of the polymer is low, and the granular behavior of ethylene propylene rubber (crude rubber) does not exist, although the polymer can be processed and vulcanized by a sulfur-accelerator system, the vulcanized product still contains a large amount of double bonds, so that the product has poor heat resistance, aging resistance and solvent resistance, and does not have the processing behavior of the ethylene propylene diene rubber and the embodied comprehensive physical and chemical properties. For example (Wangni et al, Synthesis of tin-coupled oil-extended styrene-isoprene-butadiene terpolymer [ J ], synthetic rubber industry, 2010, 33(6)) describes a process using tin tetrachloride to couple a styrene-isoprene-butadiene copolymer, the solution polymerized SIBR having not been hydrogenated and having randomly distributed polymer monomer units. The crude rubber is blocky, has low crude rubber strength and large cold flow, and injection molded products which are not completely vulcanized show poor dimensional stability and cannot meet the requirement of continuous production, namely are not suitable for the processing technology of outdoor products such as window sealing strips and the like. In Liuda et Al, ethylene-propylene rubber [ M ], a synthetic rubber industry Manual, second edition, 2006, 8), a traditional ethylene-propylene-diene monomer is introduced, which is an elastic material prepared by catalytically polymerizing ethylene, propylene and a small amount of a third monomer such as DCPD or END under the action of a Ziegler-Natta catalyst (such as V-Al), wherein the polymer molecular weight distribution index of the elastic material reaches 2-5, and a branched ethylene-propylene-diene monomer is a thermoplastic elastomer interposed between a soft resin and a hard rubber at normal temperature, and has noncrystalline, low to medium iodine values. The thermoplastic elastomer is the largest application field of the sealing parts of the carriages, the representative product is a door and window sealing strip, and the thermoplastic elastomer is a linear and profiled product which is typically suitable for continuous microwave and hot air vulcanization. For example, the existing formula of the solid door and window sealing strip is prepared from ethylene propylene diene monomer, calcium carbonate, paraffin oil, a processing rib agent, zinc oxide, stearic acid, an accelerator, sulfur and the like, the Mooney viscosity is 40-80, the sealing strip is heated by microwave, and vulcanized by hot air, and the vulcanizing time is 160 ℃/10-30 min. The vulcanized rubber has the tensile strength of 9.8Mpa, the elongation at break of 380 percent, the Shore (A)69, the burst strength of 29KN/m and the compression deformation (the pressure is about 22 hours at 70 ℃) less than 30 percent; after hot air aging (70 ℃ for 70 h): the tensile strength retention rate is 99 percent, the elongation retention rate is 72 percent, and the hardness is improved by 2.

As a sealing material, the sealing material has good surface smoothness, processing and shaping stability, higher strength, lower deformation, heat resistance, weather resistance and other properties, and requires a wider molecular weight distribution and better melt fluidity for producing a basic high polymer material for sealing, and also requires that the melt strength of the material is high enough to ensure that a formed product is not broken and deformed in the process of extruding a sealing product (strip). In addition, the product is required to have better elasticity and stretching strength. The current SEBS and SEPS have the comprehensive performance far inferior to that of ethylene propylene diene monomer rubber, and cannot meet the requirements of sealing profiles of buildings, automobiles, containers, various appliances and the like.

In chinese patent CN107663342A (gao propylo et al, "sealing strip coating compound and its preparation method and vehicle door sealing strip and its preparation method"), a sealing strip coating compound is introduced, which is prepared from the following components in parts by weight: ethylene propylene diene monomer: 70-130 parts of zinc oxide: 6.0-8.0 parts of stearic acid: 0.5-1.5 parts, paraffin oil R2291: 50-70 parts of carbon black N550: 120-140 parts, sulfur: 1.0-2.0 parts of accelerator: 3.5 to 7.5 parts of assistant and the like. Namely, the sealing strip for the vehicle door is mainly made of ethylene propylene diene monomer rubber, and is vulcanized by adopting a sulfur-accelerator system, but a specific molding processing method is not described. For example, Chinese patent CN101323693 (Wushu et al, "a dynamically vulcanized thermoplastic elastomer and its preparation method") describes a dynamically vulcanized thermoplastic elastomer and its preparation method, wherein the formulation comprises 50-80 parts of high polymerization degree polyvinyl chloride, 20-50 parts of ethylene propylene diene monomer, 10-35 parts of plasticizer, 10-30 parts of filler, 0.1-0.5 part of cross-linking agent, 0.05-1 part of cross-linking assistant, 1-5 parts of stabilizer, 0.1-1 part of lubricant, 5-20 parts of compatilizer, 1-5 parts of assistant, etc. The preparation method comprises the steps of fully mixing the components in a high-speed mixer, then carrying out melt blending, carrying out dynamic vulcanization reaction, and finally extruding and granulating. The thermoplastic elastomer is applied to the fields of wires and cables, oil-resistant rubber tubes, gas rubber tubes, sealing strips, sports goods, sole materials, conveyer belt covering rubber and the like. In Chinese patent ZL200710074252, an environment-friendly SEBS thermoplastic elastomer sealing strip material is disclosed, which comprises the following components in parts by weight: 100 parts of SEBS resin and modified substances thereof; 150-250 parts of rubber; 0.4-0.8 part of a lubricant; 0.45-0.60 part of anti-aging agent. The invention also provides a preparation method of the environment-friendly SEBS thermoplastic elastomer sealing strip material, which comprises the following steps: weighing raw materials; a mixing step; and (4) granulating. However, the molecular structure of the sealing strip material prepared by the method belongs to a non-crosslinking type, and the product has poor heat resistance, fatigue resistance, oil resistance, weather resistance and other properties. In "preparation and Performance Studies of dynamically vulcanized SEBS/EPDM blend-type thermoplastic elastomer" J "(2011 in the world rubber industry), Chenwei et al describe blending EPDM with sulfur and the like to prepare an EPDM master batch, and blending and vulcanizing the master batch with the plasticized SEBS. The first step is that EPDM and compounding agent are made into master batch on an open mill at normal temperature; secondly, dynamically vulcanizing the master batch and the SEBS on an open mill at 170 ℃, specifically, raising the temperature of the open mill to 170 ℃, fully mixing and plasticizing the SEBS and the master batch, alternately cutting the rubber for 10min, uniformly mixing the rubber mixture, and then discharging the rubber mixture; and thirdly, the lower piece rubber is molded on a flat vulcanizing machine of 25 tons/10 Mpa (190 ℃/5min), and then is cold-pressed on the flat vulcanizing machine for 5min to form the lower piece rubber. Wherein the master batch comprises EPDM 100, carbon black 40, accelerator EC-42.5, sulfur 1.8, anti-aging agent 1 and silicon-692. The hardness (A) of the product is 69-77, the 300% elongation strength is 7-9MPa, the permanent deformation is 15-20%, and the elongation is 360-. However, in the technology, the SEBS and the EPDM are mixed at high temperature, so the operation efficiency is low; the SEBS and the EPDM vulcanized rubber without the double-bond crosslinking points still have poor compatibility due to phase separation, and the product has poor continuous tensile fatigue resistance.

Similarly, a written academic paper of Chengchang university Chengjinxing, "research on special materials for environment-friendly SEBS thermoplastic elastomer sealing strips", researches on SEBS/filling oil KP6030 which is 3: and 2, SEBS/PP is 9:1, the filler is calcium carbonate, and titanate is used as a coupling agent, so that the composite extruded product has the defects of hardness of 54A, tensile strength of 11.67 MPa, elongation at break of 800 percent, permanent deformation of 45 percent, poor continuous fatigue resistance and the like.

The current SEBS and SEPS have the comprehensive performance far inferior to that of ethylene propylene diene monomer rubber, and cannot meet the requirements of sealing profiles of buildings, automobiles, containers, various appliances and the like. When the polystyrene-isoprene copolymer is hydrogenated, the soft segment chain formed by the conjugated diene in the hydrogenated polymer has the same molecular structure as that of ethylene-propylene rubber, so that the performance similar to that of the ethylene-propylene rubber can be obtained. However, no corresponding literature or commercial report exists at present for obtaining a material which can be used for sealing materials by using partially hydrogenated crude rubber and leaving partially unsaturated double bonds available for vulcanization.

In addition, for the rubber weather strip industry, the vulcanization time becomes a bottleneck to improve the industrial productivity, and the rapid development of the industrial application field of the rubber weather strip is restricted. However, from the current market, the continuous maturation of the rubber rapid vulcanization technology is making up for the defect of long vulcanization time in the past, and the temperature, the pressure and the time are three co-acting factors in the rubber vulcanization process. How to realize continuous vulcanization and improve a vulcanization system to accelerate a vulcanization process is valued and concerned by people.

Up to now, partially hydrogenated polystyrene-conjugated diene elastomers with high melt elasticity, high stiffness and broad molecular weight distribution have not been reported in the literature for use as sealing materials.

Disclosure of Invention

Aiming at the defects of SEBS and SEPS used as sealing strips in the prior art, the invention aims to provide a sealing strip (or product) which is prepared from a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer elastomer which contains partial double bonds and has long-chain branching and wide molecular weight distribution, and has good physical and mechanical properties, strong aging resistance, good heat resistance, low compression deformation, long lasting tensile and fatigue resistance time.

Another object of the present invention is to provide a method for preparing a sealing tape using a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer as a base polymer material, wherein the method has the characteristics of good processability of the mixed composite material, heat resistance and no deformation of an extruded blank or a semi-finished product, and convenience for continuous vulcanization molding, and also has the advantages of simple operation and low manufacturing cost.

In order to achieve the technical purpose, the invention provides a sealing strip material based on a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer, which comprises the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer, sulfur and auxiliary materials;

the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer is obtained by partially hydrogenating a copolymer with a structure shown in a formula 1:

S_x-b-(I_y/B_z-D_g)

formula 1

Wherein the content of the first and second substances,

S_xis a styrene homo-block, I_y/B_z-D_gIs a conjugated diene and divinyl benzene random copolymerization block; the conjugated diene comprises butadiene and/or isoprene;

the ratio of the mass of styrene units to the mass of conjugated diene units in the copolymer having the structure of formula 1 is (20 to 40)/(80 to 60), and the mass of divinylbenzene units is 0.08 to 0.16% of the total mass of conjugated diene units.

S_xIs a polystyrene block, S is a styrene unit, x is the degree of polymerization of styrene, B_zIs a butadiene block, B is a butadiene unit, z is the degree of polymerization of butadiene, I_yIs an isoprene block, I is an isoprene unit, y is the degree of polymerization of isoprene, D_gB represents a divinylbenzene block and consists of a styrene homopolymer block and a conjugated diene and divinylbenzene random copolymer block.

Preferably, the number average molecular weight of the copolymer with the structure of formula 1 is in the range of 100000-150000, the molecular weight distribution index is 2.0-5.0, and the branching distribution index is 1-8. The widely distributed polymer is beneficial to improving the subsequent processing performance of the rubber.

Preferably, the number average molecular weight of the styrene homopolymer block is in the range of 15000 to 35000. The styrene homopolymerized block is preferably in a proper molecular weight range, and the prepared polymer has proper green rubber strength and stiffness and also has enough melt strength so as to ensure that a semi-finished product (or an embryo) prepared by the polymer in units of mixing, extruding and the like has good dimensional stability; the cold flow or heat flow deformation phenomenon can not be generated at medium and low temperature such as 60-120 ℃, so that the subsequent continuous vulcanization is facilitated.

Preferably, the proportion of the amount of 1, 4-addition in the isoprene unit in the random copolymer block of a conjugated diene and divinylbenzene is 85% or more; the proportion of 1, 2-addition amount in the butadiene unit is more than 20%.

Preferably, the total iodine value of the butadiene unit and the isoprene unit of the binary random copolymer block of the conjugated diene and the divinyl benzene after partial hydrogenation is 8-30 g/100g of rubber. The polymer has a suitable number of double bonds in order to provide a suitable amount of vulcanization crosslinking points (density) during vulcanization of the compound.

The preferred partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer has a Mooney viscosity of 40 to 80, and is preferably a viscosity that maintains sufficient stiffness and moldability of the polymer.

The partially hydrogenated styrene-b-conjugated diene/divinylbenzene random copolymer is designed into a two-block structure, and aims to ensure that the polymer raw rubber has enough strength, stiffness and melt strength, and simultaneously ensure that the rubber compound has good fluidity of non-Newtonian fluid during low-temperature extrusion-shearing, so that the raw rubber is conveniently and fully mixed with the filler and the auxiliary agent in the mixing process.

The invention selects the partially hydrogenated-b-conjugated diene/divinylbenzene random copolymer as the basic elastic material because the polymer has wide molecular weight distribution index and good rubber material fluidity, is beneficial to the molding process requirements of extrusion, calendaring molding and the like, and increases the extrusion, calendaring, mould pressing and injection rates of the rubber material along with the increase of the dosage of the inorganic filler of a matching system in a certain range; the moderate long-chain branching of the raw rubber is beneficial to the reduction of the die swell rate of the rubber and the shape and stability of the rubber.

The partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer of the present invention is prepared by well-known anionic polymerization and hydrogenation methods. The method comprises the following steps:

1) polymerization reaction:

in a cyclohexane-hexane solvent system containing a structure regulator, firstly, styrene monomers are subjected to anionic polymerization reaction initiated by butyl lithium, after the styrene monomers react for 20-25 min at 50-85 ℃, mixed monomers consisting of divinylbenzene and conjugated dienes are slowly and continuously added for random copolymerization and long-chain branching, the continuous feeding time is 60-90 min, after the diene monomers are added, the reaction is continued for 20-25 min, and then the molecular weight, the molecular weight distribution index and the content of isoprene segment 1, 4-addition product and/or butadiene polymerization segment 1, 2-addition product units of the polymer in the polymerization glue solution are measured, so that the structure regulator is obtained.

2) Partial hydrogenation reaction:

adding a certain amount of nickel-based or titanium-based catalyst into the polymerized glue solution, carrying out hydrogenation reaction for 2-2.5 h under the conditions that the temperature is 70-85 ℃ and the hydrogen pressure is 1.0-1.5 MPa, stopping the hydrogenation reaction when the iodine value of the hydrogenated polymer meets the design requirement, and then carrying out water vapor condensation, extrusion, drying and grain cutting on the glue solution to obtain granular raw rubber, thus obtaining the partially hydrogenated polystyrene-b-isoprene-divinylbenzene/butadiene random copolymer raw rubber.

A nickel-based catalyst such as nickel isooctanoate/triisobutylaluminum (Ni/Al molecular ratio) 1/3.0 to 3.5; the amount of the catalyst is 3-5 mmol/100g dry polymer in terms of Ni. The titanium catalyst is, for example, 1/0.5 to 1 in terms of a molecular ratio of dicyclopentadiene titanium dichloride/dimethyl phthalate. The dosage of the dicyclopentadiene titanium dichloride catalyst is 0.12-0.15 mmol/100g of dry polymer.

The structure regulator comprises at least one of tetrahydrofurfuryl alcohol ethyl ether, ditetrahydrofurfuryl propane, tetrahydrofurfuryl alcohol hexyl ether and tertiary amine compounds; the dosage of the 1, 2-structure regulator is 10-50 mg/kg solvent. Preferred is tetrahydrofuran, which is known in the industry and is inexpensive. The dosage of the solvent is 10-50 mg/kg, the content of 1, 2-addition units in butadiene polymerization in a controlled poly-conjugated diene section is more than 20%, the content of 1.4-addition products in isoprene polymerization is more than 85%, and the content of 3, 4-addition products is not more than 15%.

In a preferred scheme, the auxiliary materials comprise a reinforcing agent, a filling agent, filling oil, a coupling agent, an accelerator, a post-effective vulcanizing agent, zinc oxide, stearic acid and an anti-aging agent.

More preferably, the reinforcing agent includes carbon black and/or white carbon black. Carbon blacks N220, N330, N550, and N234 are most suitable.

More preferably, the filler comprises at least one of ground calcium carbonate, barium carbonate, light calcium carbonate, precipitated barium sulfate and talc. The mesh number of the filler is not less than 500 meshes, the light calcium carbonate is preferred, and the inorganic filler with higher dosage is beneficial to maintaining the stability of the product after the rubber compound is extruded.

More preferably, the extender oil comprises mineral white oil. Such as naphthenic oil, paraffin oil, environmentally friendly rubber oil with low aromatic content, and the like, wherein one of the commercially available white oils No. 3, 5, 10, 25, 26, 46, NAP-10 and the like, and the mixture thereof are preferred, and the higher amount of the extender oil is also beneficial to maintaining the stability of the product after the extrusion of the rubber compound.

More preferably, the coupling agent comprises a siloxane coupling agent. The silicone-containing compound is preferably commercially available KH-550, silicon-69, silicon-75, or the like, and more preferably silicon-69 or silicon-75.

In a more preferred embodiment, the accelerator includes at least one of a vulcanization accelerator DTDC, a vulcanization accelerator TBzTD, a vulcanization accelerator TBSI, a vulcanization accelerator TMTD, and a vulcanization accelerator D.

In a more preferred embodiment, the antioxidant comprises a phenolic antioxidant and/or an organic amine antioxidant. Preferred are antioxidant A, antioxidant D, antioxidant 4010, antioxidant CPPD and antioxidant RD.

More preferably, the post-cure agent comprises ZXK-HTS. The purpose of selecting the post-effect vulcanizing agent is to enable long and flexible hexamethylene in the molecule to be embedded into sulfur atom bonds between rubber molecules through the direct participation of the molecule in a vulcanization reaction, so that the vulcanized rubber has excellent dynamic performance or anti-flexibility under the action of heat. The post-effect refers to that the rubber compound in the formula components can be continuously vulcanized at a slightly low temperature or under a milder condition after extrusion molding, and the post-effect vulcanization is a continuation of the front-stage operation process. The technical scheme of the invention uses various accelerators and super vulcanization accelerators with higher dosage in the formula, and the accelerators and the post-effect vulcanizing agent are used together, so that the vulcanized product has the advantages of good uniformity, improved heat resistance, low compression deformation and the like. This is extremely important for a weather strip product for a window of a motorcycle.

In a more preferable scheme, the sealing strip material comprises the following components in parts by mass: 100 parts of partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer; 120-140 parts of carbon black; 80-100 parts of calcium carbonate; 70-90 parts of filling oil; 7-10 parts of a coupling agent; 3-5 parts of an anti-aging agent; 3-6 parts of an accelerator; 1.5-2.5 parts of an after-effect vulcanizing agent; 4-5 parts of zinc oxide; 1-2 parts of stearic acid; 0.5-2 parts of sulfur.

In a more preferable scheme, the accelerant consists of the following components in parts by mass: 1.0-1.5 parts of a vulcanization accelerator DTDC; 0.5-1.0 part of vulcanization accelerator TBzTD; 0.5-1.0 part of vulcanization accelerator TBSI; 1.0-1.5 parts of a vulcanization accelerator TMTD; 0.5-1.0 part of vulcanization accelerator D. The sealing material is compounded by adopting a plurality of accelerators preferentially, and aims to improve the synergistic effect during the vulcanization of rubber compound so as to improve the crosslinking density of products, accelerate the vulcanization rate, shorten the vulcanization time and improve the efficiency. The vulcanization accelerator DTDC (N, N' -dithio-dihexanolactam) has the advantages of no blooming, safe scorching and high vulcanization speed, can partially replace sulfur, and can give excellent heat resistance, compression resistance and high stress at definite elongation to vulcanized rubber because the DTDC can release active sulfur under common vulcanization conditions and form a monothio bond and a disulfide bond with added sulfur between rubber molecules. The vulcanization accelerator TBzTD (tetramethylthiuram disulfide) has a longer scorch time than TMTD and is used as the rapid vulcanization auxiliary accelerator of the present invention. The vulcanization accelerator TBSI (N-tert-butyl bis-2-benzoxazolinsulfenamide) is safe at operating temperatures and does not produce carcinogenic nitrosamines. Compared with TBBS, the high-temperature-resistant rubber has the advantages of good thermal stability, long scorching time, high vulcanization speed and the like. The vulcanization accelerator TMTD has the characteristics of very strong vulcanization accelerating power and extremely fast or overspeed vulcanization. The vulcanization accelerator D has the characteristic of medium-speed vulcanization, and can be continuously vulcanized when being used together with accelerators TMTD, TBSI, TBzTD and DTDC.

The invention also provides a preparation method of the sealing strip material based on the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer, the method comprises the steps of carrying out first-stage mixing on the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer and auxiliary materials to obtain mixed rubber, and carrying out second-stage mixing on the mixed rubber and sulfur to obtain master batch; and (3) tabletting, layering, extruding, molding and vulcanizing the master batch to obtain the rubber.

In a preferred scheme, the first-stage mixing temperature is 145-150 ℃, and the mixing time is 200-280 s.

In a preferred scheme, the two-stage mixing temperature is 145-150 ℃, and the mixing time is 80-100 s.

Preferably, the molding conditions in the extrusion molding process are as follows: the length-diameter ratio L/D of the screw is 15-16, the temperature of the inlet area of the screw is set to be room temperature, the temperature of the preheating area is 90-110 ℃, and the temperature of the forming die head is set to be 130-140 ℃; the linear extrusion speed is 0.8-5 m/min, and the vacuum degree (0.01-0.1) is 101.325 KPa.

In a preferred embodiment, the vulcanization conditions are: the vulcanization temperature is 90-180 ℃, and the vulcanization time is 8-15 min.

In the preparation process of the sealing material, the mouth-shaped expansion rate of the mixed rubber material is reduced along with the increase of the use amount of the inorganic filler and the filling oil, which is beneficial to maintaining the stability of the product after the mixed rubber is extruded.

The preparation method of the sealing strip comprises the following steps:

the molding method of the sealing strip is preferably mixing-tabletting or layering-injection molding-subsequent vulcanization, the preferred equipment is an internal mixer, a tablet press, an extrusion injection molding machine and a chain transmission vulcanization box, and the molded section is vulcanized in continuous vulcanization equipment to form a molding-vulcanization continuous production (operation) line.

Namely, the specific operation process is as follows:

1) mixing the raw materials

Firstly, feeding partially hydrogenated polystyrene-b-conjugated diene/divinyl benzene random copolymer crude rubber, carbon black, calcium carbonate, filling oil, a coupling agent, an anti-aging agent, an accelerator, a vulcanizing agent, zinc oxide, stearic acid and the like into an internal mixer at one time, starting a motor, generating heat by friction of a composite material under the shearing action of a rotor in the internal mixer, mixing the mixed rubber for 240 seconds (second) at 145-150 ℃ to form a first-stage mixed rubber, sampling to measure the Mooney viscosity of the first-stage mixed rubber, adding sulfur to mix for 90 seconds to form a master batch, discharging and discharging the rubber, and sampling to measure the increase of the Mooney viscosity of the master batch.

2) Tabletting and layering of master batch

And (3) putting the master batch on a roller of an open mill, cutting the master batch three times at 3/4 left and right positions at the roller temperature of 50-60 ℃, and pressing the mixed batch into a rectangular mixed batch sample strip with the thickness of 5-10 mm (the width is set according to the requirement).

3) Extrusion injection molding

An injection molding machine was extruded using a shear head cold feed screw. And adding the prepared rubber compound strip with the thickness of 5-10 mm into an inlet of a screw extrusion injection molding machine in a cold feeding mode, and pressing the composite material into a die head in a die of the injection molding machine for extrusion molding under the action of rotation driving of the screw. Wherein, the preferable forming process conditions are as follows: the length-diameter ratio L/D of the screw is 15-16, the temperature of the inlet area of the screw is set to be room temperature, the temperature of the preheating area is 90-110 ℃, and the temperature of the forming die head is set to be 130-; the linear velocity of the sealing strip extrusion is 0.8-5 m/min, and the vacuum degree (0.01-0.1) is 101.325 Kpa. And (3) cooling, shaping and winding the sealing strip extruded from the forming die head in a cold water bath, and then storing the wound semi-finished sealing strip or product at 25-30 ℃ for 24h to perform normal vulcanization (or vulcanization). During which the Mooney viscosity increase of the extruded specimen was measured.

4) Vulcanization

The iodine value of the partially hydrogenated polystyrene-b-conjugated diene/divinyl benzene and benzene random copolymer is 8-30 g/100g of rubber, and the vulcanization speed of the rubber is accelerated along with the increase of temperature, the consumption of a vulcanizing agent and the vulcanization time.

The vulcanization conditions of the sealing strip or the product extruded by the composite rubber compound are as follows: the vulcanization temperature is 90-180 ℃, the vulcanization time is 8-15 min, the vulcanization temperature is further preferably 90-140 ℃, and the vulcanization time is 10-15 min.

The method for vulcanizing the weatherstrip for vehicle windows of the present invention is preferably a pressureless continuous vulcanizing system (e.g., preferably an MCV-15 door weatherstrip production line, which is 18m long) of a combination of a microwave heater-hot air duct type vulcanizing machine well known in the modern rubber industry.

The preferable vulcanization technological parameters are that the pressure of the vulcanization chamber is 0.25 mpa; the temperature of a first area (sealing rubber strip inlet) of the vulcanizing chamber is 80-90 ℃, and the temperature of a final area (final area) is 140 ℃, namely the temperature of the first area to the final area is increased by a proportional rate of 2.5-2.8 ℃/m; the linear speed of the transmission belt is 1.0-1.5 m/min.

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

compared with the prior elastomers such as SEBS, SEPS and the like, the elastomer has the defects of narrow molecular weight distribution, no rheological property at medium and low temperatures, incapability of filling and mixing at medium and low temperatures and crosslinking formation, and the sealing strip and the product prepared by the elastomer have the defects of low strength, large compression and tensile deformation, poor continuous tensile fatigue resistance, poor aging resistance and the like.

The invention selects a partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer elastomer as a basic high polymer material of a sealing strip or a product, the copolymer has a polystyrene block with higher molecular weight and mass part at the head end of a molecular chain, proper unsaturation degree (vulcanized cross-sulfur point), wide molecular weight distribution, ethyl, ethylene or isobutyl or isopropylidene contained in the molecular chain and the like, and the polymer is endowed with low temperature resistance, non-crystallization and high chain segment flexibility and has similar commonality with ethylene propylene rubber.

The invention selects the sealing strip formula formed by matching the partially hydrogenated polystyrene-b-conjugated diene/divinylbenzene random copolymer elastomer with inorganic fillers, softening oil, reinforcing carbon black, a composite high-efficiency overspeed vulcanizing agent and the like, has good processing performance, can be mixed and tabletted at low temperature by an internal mixer and an open multi-roll mixing mill, is extruded and injected for molding at medium temperature and is vulcanized at slightly low temperature. The continuous production line of mixing, layering, injection molding and subsequent vulcanization molding of the mixture can be carried out. The prepared sealing strip (product) has the characteristics of good rebound resilience, high stretching strength, low deformation, good fatigue and heat resistance during continuous stretching resistance, good ageing resistance and the like. The comprehensive physical properties of the ethylene propylene diene monomer are observed, and the ethylene propylene diene monomer is found to be comparable to sealing strips (or products) prepared from ethylene propylene diene monomer. The invention can be manufactured by traditional equipment and process, and has the characteristics of simple preparation method and low cost.

Detailed Description

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

The number average molecular weight and molecular weight distribution index of the polymer were measured by Gel Permeation Chromatography (GPC) in the following examples; the microstructure of the polymer is quantitatively determined by adopting H-NMR spectrum; measuring the viscosity ML (ML100 ℃ 1+4) of the raw rubber and the processing material by adopting the Mooney viscosity; measuring the physical properties of the vulcanized and semi-vulcanized tabletting glue by adopting an INSTRON tensile machine; determining the continuous anti-fatigue time of vulcanized rubber by adopting a tensile fatigue tester; adopting a Moxiya flex fatigue tester to measure the continuous fatigue cracking resistance times of the vulcanized rubber; determining the resilience of the vulcanized rubber by adopting a Rebound 3000 rubber resiliometer; the compression set of the vulcanizate was determined using a CS3000 compression set test tool.

Examples of partially hydrogenated polystyrene-conjugated diene copolymer sources: