A kind of synthetic method of high shock resistance type modifying agent for polyvinyl-chloride
The present invention relates to the synthetic method of a kind of high shock resistance type modifying agent for polyvinyl-chloride divinyl, vinylbenzene, methyl methacrylate ternary graft copolymer (being called for short the MBS resin).
As everyone knows, the MBS resin is a kind of terpolymer that is base stock by the emulsion grafting polymerization preparation by divinyl, vinylbenzene, methyl methacrylate, be synthetic novel high polymer material under the particle design notion, on submicroscopic(al) structure, have typical nucleocapsid structure.Its core is the spherical core of the rubber phase of a diameter 50-300nm, when being subjected to external impacts, can change form, and absorbing and disperseing impact energy, outside is the shell that vinylbenzene and methyl methacrylate-grafted form.Because solubility parameters is close, the shell part plays the effect of bonding interface agent between polyvinyl chloride and rubber phase particle, can form homogeneous phase in the processing mixing process, and rubber phase then is dispersed in the PVC continuum with particle state.Thereby, when adding the MBS resin of 5-10 part among the PVC, can make the resistance to impact shock of its goods improve 4-15 doubly, also can obviously improve the winter hardiness and the processing fluidity of goods simultaneously.Therefore, as one of topmost impact modifier of PVC, the MBS resin has obtained to use very widely.
Yet, in PVC modified goods, being accompanied by the PVC section bar, growing with each passing day of demands such as milky white sheet material has excellent shock resistance, the development of the MBS resin of high request becomes this area hot of research and development gradually and do not have too to the transparency.Several different Technologies have been proposed for many years in succession.The European patent EP 0 of MITSUBISHI RAYON company application for example, 144,081 and EP 77038 in a kind of method is disclosed, be with carboxylic n-butyl acrylate-Sipacril 2739OF latex, with the hole enlargement of common synthetic small particle size styrene-butadiene latex, make the large grain size latex of particle diameter more than 200nm, carry out grafting then, thereby make the MBS resin that has than high impact resistance.But it is stable that above-mentioned patent all adopts the electrolytical mode of adding inorganic salt to make hole enlargement react this, and then the adding emulsifying agent guarantees the stability of graft polymerization reaction, owing to add too much emulsifying agent in the whole polymerization process, can make that first the particle diameter of graft polymer latex diminishes, and size distribution also can by bimodal become unimodal, thereby influence its shock resistance, second can make final MBS resin smell big, particle is meticulous, and dust is bigger, and influence is used.And the patent EP 0517539 of ROHM AND HAAS company application also mentions the MBS resin for preparing the erosion-resisting characteristics excellence with the mode of polymer hole enlargement, but it has added more carboxylic-acid monomer in the building-up process of polymer hole enlargement agent, and in the grafting process, also added a large amount of (methyl) alkyl-acrylates components, this makes that on the one hand the cost of final rosin products is too high, on the other hand, the latter's adding makes prepared resin when Vicat softening point and ageing-resistant performance are improved, has reduced the requirement to erosion-resisting characteristics.And the European patent EP 62901 of the clear 60-112811 of Japanese Patent of MITSUBISHI RAYON company and BASF AG application is all mentioned method with the polymer hole enlargement and is carried out grafting after with the styrene-butadiene latex agglomeration, prepares high shock resistance type MBS resin.Yet in the styrene-butadiene latex polymerization process, all added more acrylic ester monomer in above two pieces of patents, cause the product comprehensive cost higher, and adopt a very important step of the synthetic high shock resistance type MBS resin of polymer diameter expansion method, the problem that promptly how to solve polymerization system stability is also not mentioned, utilize its impact-resistant modified DeGrain of this technology synthetic MBS resin, can not satisfy service requirements in the occasion that needs the high-impact performance.In addition, what EP-62901 adopted when synthetic macromolecule hole enlargement agent latex is acrylic ester monomer and polyvinyl ether copolymerization, and its preparation process flow process is longer, and the cost of material component is higher, and yield is on the low side, is unfavorable for the industry amplification.
Purpose of the present invention is exactly in order to solve the weak point of prior art, a kind of novel method of synthetic high shock resistance type MBS resin is provided, make the synthetic MBS of institute resin guaranteeing polymerization system stability, obviously reduce under the prerequisite of gel quantity, improve shock resistance to greatest extent.
For achieving the above object, technical scheme of the present invention is styrene-butadiene latex and the polymer hole enlargement latex that at first synthesizes small particle size, adopt the precrosslink method then, promptly elder generation adds linking agent and makes it to mix with styrene-butadiene latex before the hole enlargement reaction is carried out, add the hole enlargement agent again and carry out hole enlargement, carry out graft polymerization at last in two steps, the first step polymerization finishes back conditioned reaction system pH value for alkaline, carries out the method for secondary grafting then; Prepare particle diameter more than 250nm, and be distributed as bimodal MBS latex, thereby improved shock resistance greatly, details are as follows for its preparation process:
The first step, earlier synthetic small particle size styrene-butadiene latex (following per-cent and percentage composition all are weight percentage and weight percentage except that no specified otherwise).
The common emulsion polymerisation process of synthetic employing of styrene-butadiene latex.In order to satisfy the requirement of shock resistance, the content of divinyl is generally 70-90% in the fourth dress latex, vinylbenzene is 30-10%, initiator can be with Potassium Persulphate or ammonium persulphate, consumption is the 0.3-0.6% of monomer weight, emulsifying agent can be selected from potassium oleate, potassium stearate, nilox resin acid potassium or their compound system, but this must possess two conditions: the one, and can make polymerization system stable; The 2nd, have good thermotolerance, be unlikely to variable color in the course of processing, and influence the color and luster of product, the emulsifying agent consumption is very few, can influence the stability of system, produces a large amount of blob of viscoses; Consumption is too much, can cause product whiteness to descend again, so the consumption of emulsifying agent is the best with the 3-5% of monomer weight.In addition, for molecular weight and the gel content of controlling styrene-butadiene latex better, also need add molecular weight regulator and linking agent in the polymerization process, the former generally uses DDM dodecyl mercaptan, and its add-on is the 0.3-0.5% of monomer consumption, and the latter generally uses divinylbenzene, Ethylene glycol dimethacrylate (EGDM), triallyl cyanurates etc. are preferably used divinylbenzene, and its consumption is the 2-10% of monomer consumption.The middle control index of institute's synthetic styrene-butadiene latex is: particle diameter 60-100nm, gel content 85-95%, transformation efficiency 95-100%, solid content 31-386 (all adopting conventional method of analysis to measure).
Second step, synthetic macromolecule hole enlargement agent latex.
Polymer hole enlargement agent latex can adopt esters of acrylic acid and carboxylic-acid monomer copolymerization to make.Spendable esters of acrylic acid has (methyl) methyl acrylate, ethyl ester, and butyl ester etc., spendable carboxylic acid has vinylformic acid, methacrylic acid, methylene-succinic acid, Ba Dousuan etc.As the hole enlargement agent, require the carbochain of formed high molecular polymer core layer and contain the carbochain of carboxylic monomer that the longer the better, based on this principle, generally select butyl acrylate and methacrylic acid as comonomer.Polymerization process is carried out in two steps.The core layer of the first step synthesising macromolecule copolymer mainly is the polymerization of small part butyl acrylate.The shell of synthetic carboxylic monomer of second step participates in polymerization by whole methacrylic acids, is the consistency of increase with the core layer part, also adds the butyl acrylate of part.The initiator of this polymerization process can use Potassium Persulphate or oxidation-reduction trigger system, and its dosage is generally the 0.1-1.0% of monomer consumption.Spendable emulsifying agent generally is the vitriol of C8-C12, and sulfonate and benzene sulfonate etc. preferably use the sodium salt or the sylvite of Witco 1298 Soft Acid, and its consumption is the 1-5% of monomer consumption.Spendable linking agent and molecular weight regulator are respectively divinylbenzene and tert-dodecyl mercaptan.Its consumption is respectively the 0.5-2.0% and the 0.1-1.0% of monomer consumption,
In the 3rd step, carry out the hole enlargement of styrene-butadiene latex.
In the styrene-butadiene latex of the above-mentioned preparation of 40-65 part, at first add the linking agent of 0.5-5 part, the polymer hole enlargement agent latex that adds 0.1-3.0 part then under agitation condition in the time of 50-70 ℃ carries out hole enlargement, can make the latex of particle diameter more than 250nm.Linking agent wherein can be a divinylbenzene, Ethylene glycol dimethacrylate (EGDM), triallyl cyanurate etc., preferably divinylbenzene.Wherein the add-on of linking agent and polymer hole enlargement agent latex is two important factors, the linking agent add-on very little, cause graft latex system instability easily, produce a large amount of blob of viscoses even livering, add-on is too many, produces too much gel, can make final MBS resin treatment soffening variation, and brilliant point is too many, influences the outward appearance of product after the modification; And the add-on of polymer hole enlargement agent very little, and particle diameter does not reach desired index, can have influence on the improvement of shock resistance, and add-on is too many, can cause the reaction system breakdown of emulsion again.
In the 4th step, carry out graft polymerization reaction.
Adopt emulsion polymerization to carry out graft polymerization.The methyl methacrylate that at first adds whole formula ratios in the system after above-mentioned hole enlargement, divinylbenzene, DDM dodecyl mercaptan carries out a grafting, initiator can select for use Potassium Persulphate or di-isopropylbenzene hydroperoxide to make oxygenant, rongalite, ferrous sulfate, EDTA (b diammonium disodium edta salt) makes the initiator system of reductive agent, and the initiator add-on is the 0.4-0.8% of a grafted monomer.After a grafting finished, the pH value of regulation system was an alkalescence, and preferably pH value is 8-9, when regulating alkalescence when too weak, do not have the effect of stopping reaction system, and alkalescence is when too strong, can influence the add-on of flocculation agent in the follow-up agglomeration process, cause unnecessary waste.Then, add whole oil phase monomers such as vinylbenzene again, reach corresponding initiator system and carry out secondary grafting, wherein the consumption of initiator is the 0.4-0.8% of residual monomer consumption.
The oxidation inhibitor that adds 0.5-1.0% in the MBS of above-mentioned preparation resin latex is as commercially available oxidation inhibitor β-positive 18 carbon esters (antioxidant 1076) of (4-hydroxyl-3,5-di-tert-butyl-phenyl) propionic acid, Tyox B (oxidation inhibitor DLTDP) etc.With dilute sulphuric acid or dilute hydrochloric acid cohesion,, obtain the MBS rosin products after the drying then through washing.
Behind the MBS resin and PVC blend that the inventive method synthesizes, make the thick print of 3mm, according to the described method test of ASTM D-256 shock strength, measure thermostability according to the described method of GB1035-70, the measuring method of gel quantity is that the latex after graft reaction is finished filters with 100 eye mesh screens, and the per-cent that the weight that leaches thing accounts for the grafts gross weight then is the percentage gel quantity.
In order better to describe technical characterstic of the present invention, the spy lists following each embodiment and comparative example, but the present invention is not limited to each embodiment, if do not run counter to design of the present invention, the various changes of being done still belong to category of the present invention.Embodiment 1
(1) preparation of small particle size styrene-butadiene latex (SBR) A
In the autoclave of agitator is housed, add each material by following proportioning:
75 parts of divinyl
25 parts of vinylbenzene
3.5 parts of potassium oleates
0.5 part of potassium stearate
0.65 part in Repone K
0.5 part of Potassium Persulphate
0.5 part of DDM dodecyl mercaptan
2.5 parts of divinylbenzenes
180 parts in water
Open stirring and be warmed up to 65 ℃, stirring reaction is 9 hours under this temperature, obtains a kind of transformation efficiency 〉=95% that has, and median size is the styrene-butadiene latex (being referred to as latex A) of 85-95nm.
(2) preparation of polymer hole enlargement agent latex B
Following each component adding is had N
2In the polymerization under atmospheric pressure still of displacement pipe and stirring:
25 parts of butyl acrylates
0.5 part of divinylbenzene
0.13 part of DDM dodecyl mercaptan
0.1 part of sodium laurylsulfonate salt
0.13 part of di-isopropylbenzene hydroperoxide
Water is opened then for 100 parts and is stirred, logical N
2Replace, be warmed up to 60 ℃ simultaneously, add 40 parts in the following reduction system again:
0.6 part of rongalite
0.02 part of EDTA
0.01 part of ferrous sulfate
100 parts of sustained reactions of water were surveyed transformation efficiency 〉=75% after 3 hours, added following component and carried out secondary grafting:
55 parts of butyl acrylates
20 parts of methacrylic acids
1.5 parts of divinylbenzenes
0.375 part of DDM dodecyl mercaptan
0.75 part of sodium laurylsulfonate salt
0.375 part of peroxidation oxygen diisopropylbenzene(DIPB)
90 parts in water adds above-mentioned remaining 60 parts of reduction systems after 5 minutes, sustained reaction 4 hours, measure transformation efficiency 〉=90% after, termination reaction (gained latex is referred to as latex B).
(3) hole enlargement reaction and graft polymerization latex is synthetic
Following each component adding is had in the normal-pressure reaction kettle of stirring:
60 parts of latex A (weight by dry rubber)
1.2 parts of divinylbenzenes
200 parts in water is opened to stir also and is warmed up to 62 ℃, slowly adds dried glue weight and is the diluent (being made into the concentration of 5-10%) of 1.5% polymer hole enlargement agent latex B, and stirred 30 minutes, obtains hole enlargement latex (being referred to as latex C).
Add following component then and carry out a grafting:
19 parts of methyl methacrylates
0.38 part of divinylbenzene
0.095 part of DDM dodecyl mercaptan
0.095 part of di-isopropylbenzene hydroperoxide adds the reduction system of following composition after 5 minutes again:
0.095 part of rongalite
0.0048 part of EDTA
After 0.0024 part of polymerization of ferrous sulfate 4 reaction hour, measure transformation efficiency and reach 85%, add alkali regulation system PH=8.5.In reactor, add following each component then and carry out secondary grafting:
21 parts of vinylbenzene
0.105 part of di-isopropylbenzene hydroperoxide
0.105 part of DDM dodecyl mercaptan
0.42 part of divinylbenzene
0.105 part of rongalite
0.0050 part of EDTA
0.0025 part of ferrous sulfate reacted 5 hours under the situation of continuously stirring, obtained MBS resin latex (being referred to as latex D).Transformation efficiency is 95%, and particle diameter is 250nm.
(4) aftertreatment of MBS latex and processing test
In the above-mentioned 100 parts of latex D (weight by dry rubber) that obtain, add with 0.7 part of potassium stearate emulsive antioxidant 1076, DLTP0.4 part, dry under 60 ℃ after the centrifuge dehydration then with the dilute sulphuric acid cohesion, obtain the MBS rosin products.
Following each group is anti-according to a conventional method under 185 ℃, in opening mixing 3min on the refining formula mixing roll, under 180 ℃, on the compression molding instrument, suppress 5min then, make the thick print of 3mm:
100 parts of PVC (TK-800)
7 parts of MBS
0.5 part of lubricant G-74 (commercially available)
3 parts of stablizers 890 (commercially available)
Press ASTM D-256 method and measure the shock strength of print, press the thermostability of the method test MBS resin of GB 1035-70, its The performance test results sees Table 1.Embodiment 2
In the building-up process of above-mentioned polymerization formula latex D, grafting order of addition(of ingredients) changes into and once adds whole vinylbenzene and 1/3 methyl methacrylate, and secondary adds remaining methyl methacrylate, and all the other are identical with embodiment 1.The performance test results sees Table 1. embodiment 3
In the building-up process of above-mentioned polymerization formula latex D, the add-on of polymer hole enlargement agent (latex B) changes 1.1% of dried glue (A) weight into, and all the other are identical with embodiment 1.The performance test results sees Table 1. embodiment 4
In the building-up process of above-mentioned polymerization formula latex A, divinyl changes 90: 10 into the ratio of vinylbenzene, and all the other are identical with embodiment 1.The performance test results sees Table 1. comparative examples 1
In the building-up process of above-mentioned polymerization formula latex C, do not add divinylbenzene before the hole enlargement, all the other are identical with embodiment 1.The performance test results sees Table 1. comparative examples 2
In above-mentioned polymerization formula, do not add polymer hole enlargement agent B, all the other are identical with embodiment 1.The performance test results sees Table 1. comparative examples 3
In above-mentioned polymerization formula, replace polymer hole enlargement agent B to do the hole enlargement agent except that using inorganic salt NaCl instead, all the other are identical with embodiment 1.The performance test results sees Table 1. comparative examples 4
In the building-up process of above-mentioned polymerization formula latex D, after a grafting finishes, do not regulate the pH value of reaction system, directly carry out secondary grafting, all the other are identical with embodiment 1.The performance test results sees Table 1.
Table 1
Test number | Shock strength (J/m) | Gel quantity (%) | Ageing resistance (min) |
Embodiment 1 | ????147.5 | ????0.08 | ????75 |
Embodiment 2 | ????143.6 | ????0.02 | ????80 |
Embodiment 3 | ????139.7 | ????0.05 | ????80 |
Embodiment 4 | ????155.0 | ????0.10 | ????70 |
Comparative example 1 | ????---- | Livering | ????---- |
Comparative example 2 | ????87 | ????0.12 | ????75 |
Comparative example 3 | ????118 | ????1.06 | ????75 |
Comparative example 4 | ????136 | ????12.6 | ????60 |