CN106947072A - A kind of preparation technology of makrolon - Google Patents

Abstract

A kind of preparation technology of makrolon, comprises the following steps：S1, generalWithMelted, be added in transesterification reactor respectively, and add catalyst and carry out ester exchange reaction, obtain oligomer；S2, the resulting oligomer in S1 is added in polycondensation reactor carries out polycondensation reaction, obtain polycondensation product；S3, the polycondensation product in S2 is added in extruder be extruded, cool down and dry by water-bath after extrusion, be transported in comminutor and carry out shear granulation, the polycarbonate pellets of finished product；Wherein R is cycloalkyl, and R ' and R " are alkyl or phenyl.By using above-mentioned technical proposal, the makrolon of bisphenol Z series is prepared using the mode of melting, the use of a large amount of solvents is so saved, so as to not only improve saving resource, is not easy to cause environment excessive pollution again.

Description

A kind of preparation technology of polycarbonate

technical field

The invention relates to the field of chemical production, in particular to a preparation process of polycarbonate.

Background technique

Polycarbonate (referred to as PC) is a high molecular polymer containing carbonate groups in its molecular chain. Due to its special structure, it has become the fastest-growing general-purpose engineering plastic among the five major engineering plastics. At the same time, according to the structure of the ester group, it can be divided into various types such as aliphatic, aromatic, and aliphatic-aromatic. Among them, the low mechanical properties of aliphatic and aliphatic-aromatic polycarbonates limit their application in engineering plastics. At present, only aromatic polycarbonate has been produced industrially. In particular, bisphenol A polycarbonate has the advantages of good mechanical strength, excellent heat resistance and high impact strength, and its preparation process is relatively mature, so it is used in many fields.

For example, it is used in organic photoconductors, but because it is only soluble in haloalkane, a small amount of haloalkane will remain in the film when it is coated in use, and when the photoconductor is used, chlorine free radicals will be generated due to the photochemical action of haloalkane to make the transmission material Dissociation accelerates the aging of the photoconductor and shortens the service life of the photoconductor. The bisphenol Z polycarbonate has the advantages of general bisphenol A polycarbonate, and it can be dissolved in aromatic hydrocarbons, which can effectively avoid the above-mentioned shortcomings of bisphenol A polycarbonate, thereby effectively reducing the residual potential and dark Attenuation rate, improve the application performance of photoconductor.

And prior art bisphenol Z type polycarbonate as long as it is produced with triphosgene and bisphenol Z as raw material, for example the Chinese patent " a kind of synthetic method of bisphenol Z type polycarbonate " that application number is 200610130498 discloses A method for synthesizing bisphenol Z type polycarbonate is proposed, in which bisphenol Z is dissolved in an aqueous sodium hydroxide solution with a mass concentration of 3%, and the molar ratio of bisphenol Z to bisphenol Z is 0.33～ 0.67 triphosgene haloalkane solution, after adding tetrabutylammonium bromide and triethylamine with a molar ratio of 5% to 15% to bisphenol Z, carry out liquid-liquid two-phase polycondensation at 20-40°C for 2-3 hours . After the reaction, directly wash with deionized water repeatedly until the water phase does not contain chloride ions, add methanol and stir, and separate the precipitate to obtain bisphenol Z-type polycarbonate. Although, the raw material of this synthetic method is easy to get, and reaction temperature is low, and product quality is good, and thermal stability is good, is convenient to realize suitability for industrialized production. The viscosity-average molecular weight of the prepared product ranges from 3×10 ⁴ to 14×10 ⁴ , and the product yield can reach 90% based on bisphenol Z. However, in the whole preparation process, a large amount of alkali and halogenated alkanes are needed as solvents, which will easily cause a lot of waste of resources and environmental pollution in the production process.

Contents of the invention

The purpose of the present invention is to provide a polycarbonate preparation process, which can not only reduce the waste of resources and environmental pollution, but also simplify the operation steps.

The above-mentioned purpose of the present invention is achieved by the following technical scheme: a kind of preparation technology of polycarbonate comprises the following steps:

S1, will Carry out melting separately, join in the transesterification reactor, and add catalyst to carry out transesterification reaction, obtain oligomer;

S2, adding the oligomer obtained in S1 into a polycondensation reactor to carry out a polycondensation reaction to obtain a polycondensation product;

S3. The polycondensation product in S2 is added to an extruder to be extruded, after extrusion, it is cooled and dried in a water bath, and then transported to a granulator for shear granulation to obtain finished polycarbonate granules;

Wherein R is cycloalkyl, and R' and R" are alkyl or phenyl.

As a preference, is bisphenol Z, For diphenyl carbonate.

Preferably, the molar ratio of diphenyl carbonate to bisphenol Z is 1.03-1.05.

By adopting the above technical scheme, the polycarbonate of bisphenol Z series is prepared by melting, which saves the use of a large amount of solvents, which is beneficial to saving resources and is not easy to cause excessive pollution to the environment.

Moreover, the amount of diphenyl carbonate added is excessive compared with bisphenol Z, so that both ends of the prepolymer molecule obtained in the process of transesterification are ester groups with strong activity, which is beneficial to ensure that the prepolymer Molecular activity, so that after the prepolymer is sent into the polycondensation reactor, the polycondensation reaction can be carried out rapidly, thereby greatly improving the production efficiency of polycarbonate.

Preferably, the catalyst is a mixture of lithium halide and lithium triethylborohydride.

Preferably, the lithium aluminum halide is lithium chloride.

By adopting the above technical scheme, lithium triethyl borochloride has stronger selective reduction than its parent lithium tetrahydroborate, and it can efficiently reduce the ester group in diphenyl carbonate to hydroxyl. Lithium chloride as part of the catalyst can enhance the progress of the new esterification reaction. Therefore, under the joint action of lithium chloride and lithium triethyl borochloride, the transesterification reaction between bisphenol Z and diphenyl carbonate can be greatly improved.

Preferably, when the polycondensation reaction in S2 is in progress, the vacuum pump evacuates the polycondensation reactor, the pressure of the polycondensation reactor is 0.1-0.01kPa, and the temperature is 290-310°C.

By adopting the above technical scheme, since a large amount of phenol will be produced in the process of polycarbonate production, which will affect the yield of polycarbonate, the vacuum pump will evacuate the polycondensation reactor into a vacuum state, so that phenol can be removed quickly.

Preferably, during the polycondensation reaction in S2, a defoamer is added to the polycondensation reactor.

By adopting the above technical scheme, since the volatilization of phenol from the raw material is mainly carried out in the form of bubbling, and in the process of polycondensation reaction, the viscosity of the raw material is relatively large, and the bubbles are difficult to burst, which will affect Polycarbonate final product quality. Therefore, the addition of defoaming agent can quickly eliminate the bubbles in the polycondensation reaction process, which is beneficial to easily improve the removal rate of phenol.

Preferably, the defoamer is polydimethylsiloxane.

By adopting the above technology, polydimethylsiloxane not only has the effect of ordinary defoaming agent, but also can rapidly break the air bubbles. At the same time, a small amount of copolymer can be formed with polycarbonate during the polycondensation reaction, so that silicon oxygen groups are introduced into the polycarbonate molecular chain, thereby greatly improving the hardness and scratch resistance of polycarbonate .

Preferably, during the transesterification reaction in S1, the temperature of the transesterification reactor is 210-280° C., and the pressure is 10-0.1 kPa.

In order to obtain high-molecular-weight polycarbonate, the low-molecular-weight product phenol or diphenyl carbonate produced by the reaction must be removed from the reaction system as much as possible without interruption. The transesterification reactor is in a relatively large vacuum state under working conditions, so that it is easier to volatilize the low-molecular product phenol or diphenyl carbonate from the raw material system, and then can be easily extracted.

Preferably, in the middle stage of the transesterification reaction in S1, a halogen-free hyperbranched polymer is added to the transesterification reactor.

By adopting the above technical scheme, the molecules of polycarbonate will be introduced into the halogen-free hyperbranched polymer. By using the halogen-free hyperbranched polymer as the flow modifier of polypropylene, the molecular weight and molecular weight distribution of the polypropylene resin will not be changed. Under certain circumstances, it can improve the fluidity of polypropylene, improve the appearance of products, reduce energy consumption, and reduce production costs.

In summary, the present invention has the following beneficial effects:

1. Polycarbonate is produced by transesterification and polycondensation of bisphenol Z and diphenyl carbonate in a molten state, which saves the input of solvents, saves resources and reduces environmental pollution;

2. By adding hyperbranched polymers in the polycondensation process of polycarbonate, the flow properties of polycarbonate can be improved under the premise of ensuring the mechanical properties of polycarbonate;

3. During the polycondensation process, add a defoamer to the polycondensation reactor, which can speed up the bursting of the bubbles, which is beneficial to the vacuum pump to remove the small molecule phenol or diphenyl carbonate produced during the reaction, thereby facilitating the acquisition of high molecular weight of polycarbonate.

Description of drawings

Fig. 1 is the preparation process flowchart of polycarbonate;

Fig. 2 is the preparation flowchart of hyperbranched polymer.

detailed description

The present invention will be described in further detail below in conjunction with accompanying drawing 1 .

The present invention is based on As a raw material, a transesterification reaction occurs in a molten state, and then a polycondensation reaction is carried out to make polycarbonate. Where R is cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclopentyl, etc., and R' and R" are alkyl or phenyl, such as methyl, ethyl, propyl and phenyl .here, Bisphenol Z and diphenyl carbonate, respectively.

Embodiment one,

Step 1: Put diphenyl carbonate and bisphenol Z in a molar ratio of 1.03, and put them into two melting tanks to heat up and completely melt;

Step 2: transport the melt of diphenyl carbonate and bisphenol Z to the same mixing tank for stirring and mixing, the stirring speed is 800rpm, and the stirring time is 10min;

Step 3: transport the mixture in the mixing tank to a transesterification reactor with a separation tower and a vacuum pump at one time, and add a catalyst to carry out transesterification reaction, and add hyperbranched polymer when the reaction is in the middle, and the total reaction time is 1 hour. The prepolymerized reactant, wherein the temperature during the transesterification reaction is 210°C, and the pressure is 10kPa;

Step 4: Transport the prepolymerized reactant to a polycondensation reactor with a condenser and a vacuum pump, and put in a defoamer to carry out a polycondensation reaction. The total reaction time is 2 hours to obtain a semi-finished polycarbonate. The temperature of the polycondensation reactor is At 290°C and under a pressure of 0.1kPa, the yield of polycarbonate was 95.2%, and the weight-average molecular weight Mw was 21,000.

Step 5: Pass the semi-finished polycarbonate into the extrusion process for further melt extrusion. After the extruded polycarbonate strips are cooled in a water bath, they are transported to the drier for cold air drying, and then transported to granulation Shear granulation is carried out in the machine to obtain finished polycarbonate granules.

Here, the catalyzer is a mixture of lithium halide and lithium triethylborohydride, and the lithium halide can be lithium chloride, lithium bromide and lithium iodide, preferably lithium chloride, which can pass through lithium triethylborohydride The strong selective reductivity reduces the ester group to a hydroxyl group, and then under the action of lithium chloride, a new esterification reaction is carried out rapidly, thereby greatly improving the efficiency of the entire transesterification reaction. Here lithium chloride and lithium triethylborohydride are mixed in a mass ratio of 1:1, and meanwhile, the mass of the overall catalyst is 3% of the mass of diphenyl carbonate.

Moreover, the defoamer is a silicone defoamer, preferably a polydimethylsiloxane defoamer, which not only has the characteristics of a general defoamer, but also can quickly cause the bubbles in the reactant to burst, thereby facilitating The vacuum pump removes the small molecule phenol and diphenyl carbonate, and can also co-polymerize with polycarbonate to introduce siloxane groups into polycarbonate, thus improving the hardness and resistance of polycarbonate. Abrasion. The quality of the polydimethylsiloxane here is 2% of the weight of the prepolymerization reactant.

In addition, as shown in Figure 2, the halogen-free hyperbranched polymer is prepared by the following preparation method: first exhaust the air in the reaction system, pass in an inert gas, and first add 1,4-butanediol according to the amount - Di-(2-bromoisobutyric acid) and butyl acetate were added to the reaction device, then ferric chloride, α-methylstyrene, ascorbic acid and PCDI were put into the reaction device in sequence, stirred and reacted at 70°C for 17h, and then used ¹ H-NMR nuclear magnetic resonance detection double bond conversion rate, the conversion rate reaches 80% or more is the reaction end point, then add tert-dodecyl mercaptan, react at 35 °C for 15 hours, add benzoyl peroxide to remove excess Tertiary dodecyl mercaptan, obtain this halogen-free hyperbranched polymer after precipitation.

The halogen-free hyperbranched polymer obtained here has been modified by tert-dodecyl mercaptan, which has excellent compatibility with prepolymerization reactants in the polycondensation reactor. Wherein by molar ratio, 1,4-butanediol-two-(2-bromoisobutyric acid): ferric chloride=100:0.03, ascorbic acid: ferric chloride=15:1, ascorbic acid: PCDI=1: 1,1,4-Butanediol-di-(2-bromoisobutyric acid): tert-dodecyl mercaptan=1:2, tert-dodecyl mercaptan:benzoyl peroxide=1: 0.7.

Embodiment two to embodiment four in the following table and comparative example one and comparative example two are all based on the operating steps of embodiment one, wherein comparative example one does not add hyperbranched polymer, and comparative example two does not add:

And, according to the step of embodiment three and raw material, be used to carry out the preparation of the polycarbonate of comparative example one and comparative example two, wherein the difference of comparative example one and embodiment three is that no halogen-free hyperbranched polymer is added, and for The difference between the second example and the third example is that no defoamer is added.

Test Methods:

Determination of plastic fluidity: GB/T 21060-2007;

Plastic tensile performance test: GB1040-92;

Plastic bending performance test method: GB/T 9341-2000;

Rockwell hardness: GB/T3398.2-2008;

Plastic abrasion resistance test method: JBT 6072-1992.

Detect the various performances of the prepared polycarbonate of embodiment one to embodiment five and comparative example one and comparative example two according to above-mentioned detection method, obtain the following table result:

Through the comparison of Example 3 and Comparative Example 1, it can be concluded that the fluidity of polycarbonate has been greatly improved without changing the mechanical properties, which is beneficial to reduce production costs. Compared with Example 3 and Comparative Example 2, it can be concluded that the hardness and scratch resistance of the polycarbonate of the present invention have been greatly improved. Moreover, the preparation steps of the whole polycarbonate are simple, and the energy consumption is reduced, thereby greatly reducing the production cost, and the efficiency is higher than that of similar polycarbonate production methods, and the produced polycarbonate is more suitable for preparing photoconductors.

This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contribution as required after reading this specification, but as long as they are within the rights of the present invention All claims are protected by patent law.

Claims (10)

1. A preparation technique for polycarbonate, comprising the following steps: S1, will Carry out melting separately, join in the transesterification reactor, and add catalyst to carry out transesterification reaction, obtain oligomer; S2, adding the oligomer obtained in S1 into a polycondensation reactor to carry out a polycondensation reaction to obtain a polycondensation product; S3. The polycondensation product in S2 is added to an extruder to be extruded, after extrusion, it is cooled and dried in a water bath, and then transported to a granulator for shear granulation to obtain finished polycarbonate granules; Wherein R is cycloalkyl, and R' and R" are alkyl or phenyl. 2. according to the preparation technology of a kind of polycarbonate shown in claim 1, it is characterized in that: is bisphenol Z, For diphenyl carbonate. 3. The preparation process of a kind of polycarbonate according to claim 2, characterized in that: the molar ratio of diphenyl carbonate and bisphenol Z is 1.03～1.05. 4. according to the preparation technology of a kind of polycarbonate shown in claim 1, it is characterized in that: described catalyst is the mixture in lithium halide and lithium triethyl borohydride. 5. the preparation technology of a kind of polycarbonate according to claim 4 is characterized in that: described halogenated lithium is lithium chloride. 6. the preparation technology of a kind of polycarbonate according to claim 1 is characterized in that: when polycondensation reaction is carried out in S2, vacuum pump carries out vacuumizing process to polycondensation reactor, and the pressure of polycondensation reactor is at 0.1～0.01kPa, The temperature is 290-310°C. 7. A kind of preparation technology of polycarbonate according to claim 6 is characterized in that: polycondensation reaction process in S2, adds defoamer in polycondensation reactor. 8. The preparation process of a kind of polycarbonate according to claim 7, characterized in that: the defoamer is polydimethylsiloxane. 9. A polycarbonate preparation process according to claim 1, characterized in that: during the transesterification reaction in S1, the temperature of the transesterification reactor is 210-280° C., and the pressure is 10-0.1 kPa. 10. The preparation process of a kind of polycarbonate according to claim 1, characterized in that: in the middle stage of the transesterification reaction in S1, a halogen-free hyperbranched polymer is added to the transesterification reactor.