CN102775615A - Method for preparing polystyrene plastic small balls and product prepared from polystyrene plastic small balls as well as application of polystyrene plastic small balls - Google Patents

Abstract

The invention provides a method for preparing polystyrene plastic pellets, products prepared therefrom and applications thereof. Including: (1) dissolving the oil phase solute in an organic solvent to obtain an oil phase, the oil phase solute is 4 to 40% by weight of the organic solvent, and the oil phase solute is polystyrene or polystyrene and styrene monomer For the mixture, the weight of polystyrene is 15% to 100% of the total weight of the oil phase solute; when the oil phase solute contains styrene monomer, an initiator for styrene polymerization is dissolved in the organic solvent at the same time; (3) add the oil phase to the water phase at normal temperature, the weight ratio of the oil phase to the water phase is not more than 1:2, and the temperature rises to dynamically disperse; (4) separate the liquid and solid of the emulsion into small balls , and then dried to obtain polystyrene plastic pellets. The method of the invention has a simple process, can solve the problem of white pollution on the one hand, and makes it possible to apply a large amount of low-cost solid lubricants on the other hand.

Description

A method for preparing polystyrene plastic pellets and the product and application thereof

technical field

The present invention relates to the field of petroleum exploration, and more specifically, relates to a method for preparing polystyrene plastic pellets, a polystyrene plastic pellet product and an application thereof.

Background technique

With the development of oil exploration, the drilling depth continues to increase, and the number of cluster wells, high-inclination directional wells and horizontal wells is also increasing rapidly. Avoiding pipe sticking, reducing drill torque, and reducing drill string wear have become urgent solutions Problem, adding lubricant to the drilling fluid can effectively avoid accidents such as pipe sticking. Compared with liquid lubricants, solid lubricants are added to the drilling fluid in the form of solids to lubricate the well wall and prevent sticking and sticking. It has the advantages of convenient transportation, no fluorescence, and good lubrication performance. The currently used solid lubricants for drilling fluids mainly include the following two types according to the lubrication mechanism.

(1) Graphite, the lubrication mechanism mainly depends on the sliding between layers. Graphite is a crystalline form of carbon, with a hexagonal lattice, and the atoms are arranged in layers. The distance between carbon atoms on the same layer of crystal plane is 0.142nm, and they are covalently bonded to each other; the distance between layers The thickness is 0.34nm, the atoms are bonded by molecular bonds, and the force between layers is very small, so it is easy for relative sliding to occur between layers, thus playing a very good role in reducing friction. As a lubricant, graphite powder has the characteristics of high temperature resistance, no fluorescence, obvious effect of reducing friction, small dosage, and no adverse effect on drilling fluid performance. After being added to the drilling fluid, it can be firmly adsorbed (including physical and chemical adsorption) on the surface of the drilling tool and the well wall rock, thereby improving the friction state between the friction contact surfaces and reducing friction.

(2) The spherical ball is similar to a small ball. The lubrication mechanism is between the drill string and the well wall, which converts sliding friction into rolling friction, thereby greatly reducing torque and resistance, and preventing sticking and sticking, mainly including Glass spheres and plastic spheres. Glass balls are vitreous, brittle and easily broken during drilling. They are generally used in casing running, but not in conventional drilling. Plastic pellets are mainly copolymers of styrene and divinylbenzene, which are tough, non-toxic, non-fluorescent, and recyclable. It is acid-resistant, alkali-resistant, insoluble in water and oil, inert in drilling fluids, and can be matched with various types of water-based and oil-based drilling fluids. It is a high-efficiency lubricant and has developed rapidly in recent years.

Since graphite is a natural mineral material, glass pellets cannot be used in the drilling process due to their high brittleness. The research on solid lubricants for drilling fluids mainly focuses on plastic pellets. At present, there are two main methods for preparing plastic pellets:

(1) It is mainly composed of styrene or acrylate, and it is copolymerized with diolefins. Using the method of suspension polymerization, styrene is used as monomer, divinylbenzene is used as crosslinking agent, dibenzoyl peroxide is used as initiator, polyvinyl alcohol and gelatin are used as dispersant to synthesize plastic pellets, the currently used plastics Pellets are mostly prepared by this method. The disadvantage is that monomers need to be used during synthesis, and the cost of divinylbenzene is high; in addition, the particle size of microspheres prepared by this method is small, generally below 2 μm.

(2) Organic-inorganic composite, using styrene and inorganic layered materials as raw materials, using the method of in-situ intercalation suspension polymerization of monomers to prepare polystyrene composite particles, polystyrene/inorganic composite plastic pellets, which can be adjusted by adjusting the stirring Strength, dispersant dosage, polymerization time and temperature, etc. to control the particle size of the product, the problem with this method is that the current in-situ intercalation technology is immature, the reaction process is not easy to control, and the product yield is low.

Contents of the invention

In order to solve the problems in the prior art, the invention provides a method for preparing polystyrene plastic pellets and a polystyrene plastic pellet product prepared therefrom. The process is simple, and large-diameter plastic pellets can be prepared. On the one hand, it can solve the problem of "white pollution", and on the other hand, it makes it possible to apply low-cost solid lubricants in large quantities.

One of purposes of the present invention is to provide a kind of preparation method of polystyrene plastic pellet. The method comprises dissolving the oil phase solute in an organic solvent and mixing uniformly as the oil phase; the oil phase solute is polystyrene or a mixture of polystyrene and styrene monomer; dissolving the dispersant or the dispersant and the emulsifier Make a water phase in water; fully mix the above oil phase and water phase, so that the oil phase is uniformly dispersed in the water phase to prepare an emulsion; raise the temperature of the emulsion to volatilize the organic solvent and solidify the oil phase droplets; then liquid-solidify the emulsion Separation, the solid phase is separated, and the polystyrene plastic pellets are obtained after drying.

Specifically, the method of the present invention comprises the following steps:

(1) The oil phase solute is dissolved in an organic solvent to obtain an oil phase, the oil phase solute is 4 to 40% of the weight of the organic solvent, and the oil phase solute is polystyrene, or polystyrene and styrene monomer mixture, the weight of polystyrene is 15-100% of the total weight of the oil phase solute, preferably 30-70%; when the oil phase solute contains styrene monomer, the organic solvent is simultaneously added with styrene polymerization Initiator, the amount of the initiator for styrene polymerization is 0.02-3% of the weight of styrene monomer, preferably 0.1-0.5%;

The solubility parameter of the organic solvent is 8.0-10.2; the solubility in water is less than or equal to 30g/l, and the boiling point is less than 100°C.

(2) add dispersant and emulsifier in water and make aqueous phase, the weight of dispersant accounts for 0.12～8% of water weight, preferably 1～3%, the weight of emulsifier accounts for 0～1.0% of water weight, preferably 0.1-0.3%; the water is common water in the prior art, including tap water, distilled water and the like.

(3) At room temperature, add the oil phase to the water phase, the weight ratio of the oil phase to the water phase is not more than 1:2, preferably 1:3 to 1:7, and perform dynamic dispersion at the same time to obtain a uniformly emulsified emulsion ;Heat the emulsion to 40-60°C, maintain the dynamic dispersion for at least 1 hour, then raise the temperature to 60-95°C, maintain the dynamic dispersion for at least 0.5 hours, and then end, keep the oil-water emulsion in dynamic throughout the dispersion process.

Preferably, the oil phase is added to the water phase, and dynamic dispersion is carried out at the same time, after obtaining a uniformly emulsified emulsion, the emulsion is heated to 43-45°C, and the dynamic dispersion is maintained for 1.2-2.5 hours, and the temperature is continued to rise to 65-75°C, and the dynamic dispersion is maintained It ends after 1-2 hours.

For the above, the emulsion can be heated by conventional heating methods in the prior art, such as electric heating and water bath heating.

(4) The emulsion is subjected to liquid-solid separation to separate the pellets, and then the pellets are dried to obtain the polystyrene plastic pellets. The liquid-solid separation described therein can adopt common liquid-solid separation methods in the prior art, including centrifugal separation, filtration separation, etc., and suction filtration separation is preferred in filtration separation. The separation equipment adopted is also various filtering devices, centrifuges or vacuum suction devices etc. existing in the prior art. The separated liquid can be reused.

The drying can adopt common drying methods, such as air drying at room temperature and oven drying. Of these, drying is preferred. The drying time is not limited, generally it can be 10-36 hours until the pellets are dried. The drying temperature is generally 70-120°C.

In the method of the present invention, when the mixture of polystyrene and styrene monomer is used as the oil phase solute, under the conditions of temperature and initiator of the method of the present invention, styrene can be polymerized into polystyrene, and simultaneously due to styrene The monomer is liquid, so the viscosity of the prepared oil phase is lower than that of the oil phase prepared entirely using polystyrene plastics as raw materials. When the viscosity of the oil phase is low and other conditions remain unchanged, the oil phase particles in the formed emulsion are finer and more uniformly distributed, and the formed pellets have smaller particle size and narrower distribution. Therefore, the ratio of polystyrene and styrene mixture can also be used as one of the factors to adjust the particle size and distribution of pellet products.

In the above method step (1) of the present invention, the polystyrene in the oil phase solute is not limited to polystyrene industrial products, but also includes polystyrene waste and old resin reclaimed materials, such as waste polystyrene foam packaging materials, etc. . These recycled materials can be obtained from the market. If it is recycled polystyrene waste plastic, it can be cleaned and dried for later use.

In step (1) of the method of the present invention described above, the organic solvent is preferably at least one of the following substances: benzene (solubility parameter 9.2, boiling point 80.1 ° C, solubility 1.8g/l), dichloromethane (solubility parameter 9.7, boiling point 39.75°C, solubility 20g/l), chloroform (solubility parameter 9.3, boiling point 61.15°C, solubility 7.5g/l), 1,1-dichloroethane (solubility parameter 9.8, boiling point 57.3°C, solubility: hardly soluble in water), 1,2-dichloroethane (solubility parameter 9.8, boiling point 83.48°C, solubility 10.47g/l), carbon disulfide (solubility parameter 10.0, boiling point 46.23°C, solubility 2.94g/l), 1,1,1- Trichloroethane (solubility parameter 9.6, boiling point 74°C, solubility: less than 30g/l, slightly soluble in water), carbon tetrachloride (solubility parameter 8.6, boiling point 77°C, solubility 0.8g/l), cyclohexane (Solubility parameter 8.2, boiling point 80.7°C, solubility: insoluble in water), etc.

In step (1) of the method of the present invention described above, the initiator for styrene polymerization is an initiator used in the prior art for styrene polymerization to generate polystyrene. The initiator is preferably at least one selected from azo initiators, organic peroxygen initiators, inorganic peroxygen initiators, and oxidation-reduction initiators;

The azo initiator is preferably at least one of azobisisobutyronitrile and azobisisoheptanonitrile;

Described organic peroxygen initiator is preferably cumene hydroperoxide, tert-butyl hydroperoxide, dibenzoyl peroxide, lauryl peroxide, di-t-butyl peroxide, dicumyl peroxide, At least one of diisopropyl peroxydicarbonate;

Described inorganic peroxygen initiator is preferably at least one in potassium persulfate and ammonium persulfate;

Described oxidation-reduction initiator comprises water-soluble oxidation-reduction initiator and oil-soluble oxidation-reduction initiator:

Wherein the oxidant in the water-soluble oxidation-reduction initiator is preferably at least one of inorganic peroxygen initiator and hydroperoxy initiator, and the reducing agent is preferably ferrous salt, sodium bisulfite, sodium thiosulfate, alcohol and multiple at least one of amines; more preferably ammonium persulfate-sodium bisulfite initiator. Wherein the oxidant in the oil-soluble oxidation-reduction initiator is selected from at least one of organic peroxygen initiators, and the reducing agent is selected from at least one of tertiary amine, ferrous naphthenate and mercaptan.

The styrene polymerization initiator is more preferably a water-soluble oxidation-reduction initiator composed of dibenzoyl peroxide, lauryl peroxide, potassium persulfate, ammonium persulfate, ammonium persulfate-sodium bisulfite, At least one of the oil-soluble oxidation-reduction initiators composed of dibenzoyl peroxide-tertiary amines.

In the method step (2) of the present invention described above, the dispersant can be selected from various dispersants that play an emulsifying and dispersing role in the prior art, preferably xanthan gum, gelatin, carboxymethyl cellulose, polyvinylpyrrolidone, At least one of hydroxyethyl cellulose and polyvinyl alcohol.

In the step (2) of the method of the present invention described above, the emulsifier can be selected from various emulsifiers that play an emulsifying role in the prior art. Preferred are sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sorbitan oleate (Span 80), sorbitan monostearate (Span 60), at least one of alkylphenol polyoxyethylene ether (OP～10).

In the method step (3) of the present invention described above, the dynamic dispersion includes various dispersion methods in the prior art, such as stirring, high-speed stirring, dispersion by SPG membrane emulsification, dispersion by ultrasonic dispersion, etc. etc., as long as the water phase and the oil phase can be fully dispersed and mixed evenly, they can be used.

Wherein SPG membrane emulsification is a kind of emulsion dispersion method in the prior art. SPG membrane is a kind of porous inorganic membrane. The characteristic of the SPG membrane emulsification method is that the dispersed phase enters the continuous phase through the membrane to obtain a very well-dispersed emulsion, thereby producing monodisperse microspheres. In the method of the present invention, the dynamic dispersion mode is preferably the SPG film emulsification mode. When the SPG membrane emulsification method is used to carry out the dispersion and emulsification of the oil phase and the water phase, the dynamic dispersion maintained in the subsequent heating process in step (3) can be the dynamic dispersion of the stirring method.

When the SPG membrane emulsification device is used as a dynamic dispersion method to prepare small balls, the size of the oil phase droplet in the emulsion is mainly affected by the membrane pore size, but it is also related to the viscosity of the oil phase as the dispersed phase and the amount of dispersant in the water phase as the continuous phase. Generally, the greater the viscosity of the oil phase, the larger the particle size; the more the water phase dispersant content, the smaller the particle size. The particle size of the finally obtained pellets is generally 2 to 5 times the pore size of the SPG membrane, and the distribution coefficient is small. Therefore, the average particle size of the pellets can be specifically regulated by selecting SPG membranes with different pore sizes, adjusting the viscosity of the oil phase, and adding dispersants and emulsifiers in the water phase. When other conditions are the same, the average particle size of the pellets can be specifically controlled by selecting SPG membranes with different pore sizes.

The second object of the present invention is to provide a polystyrene plastic pellet product prepared by the above method. The polystyrene plastic pellets obtained by the above method can be adjusted by adjusting the stirring speed, the amount of dispersant and emulsifier, the weight ratio of polystyrene and styrene monomer in the oil phase solute, or according to a more advanced emulsification and dispersion method, such as SPG membrane emulsification is used to adjust and control the size of the pellets, and various grades of pellets with a relatively narrow distribution can be obtained to suit specific applications.

The average particle size of the pellets obtained by the above method has many specific control factors. For example: increasing the amount of dispersant, the particle size becomes smaller; increasing the stirring speed, the particle size becomes smaller, and the ratio of styrene monomer to polystyrene increases, the particle size becomes smaller. Ultrasonic dispersion depends on the frequency of the ultrasonic cleaner. The particle size of SPD membrane emulsification is controlled by the membrane pore size. Therefore, the particle size of the polystyrene plastic pellets obtained by the method of the present invention is preferably controllable and adjustable from several microns to hundreds of microns, and the average particle size is preferably 3-300 μm, more preferably 20-100 μm. Compared with the prior art, it is difficult to form microspheres exceeding 3 μm by simply polymerizing monomers in the prior art.

The third object of the present invention is to provide an application of polystyrene plastic pellets in petroleum drilling fluid.

The polystyrene plastic pellets prepared by the present invention are particularly suitable for use as solid lubricants in petroleum drilling fluids, but are not limited thereto, and can also be applied to other technical fields that require plastic pellets as additives, such as cosmetics and coatings etc.

Invention effect of the present invention:

(1) The particle size of the plastic pellets prepared by this method is uniform, and the circularity of the product is good. The particle size of the product can be controlled by adjusting the amount of dispersant, stirring speed, styrene content in the oil phase solute, and selecting an advanced emulsification dispersion method. It is especially suitable for use as a solid lubricant in the field of oil drilling;

(2) The waste polystyrene foam plastics can be used as raw materials by adopting the method, and the "white pollution" can be transformed into high value-added products, which can be used as a treatment method for waste plastics;

(3) Both solvent and water phase can be recycled and reused in the preparation process, with good environmental protection and low cost;

(4) The plastic pellets produced by this method can also be applied to other technical fields that require plastic pellets as additives, such as cosmetics, coatings and the like.

Description of drawings

The scanning electron micrograph of the polystyrene plastic beads prepared in Fig. 1 Example 2, the magnification is 1000 times.

Detailed ways

Below in conjunction with embodiment, further illustrate the present invention.

Raw material in the embodiment:

Styrene monomer manufacturer: Beijing Huawei Ruike Chemical Co., Ltd.

All other raw materials are commercially available.

Example 1:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 2.4g of the above-mentioned clean polystyrene foam, add it to 59.6g of cyclohexane, dissolve the polystyrene completely, and stir to obtain the oil phase; the oil phase solute is 100%wt Polystyrene, which accounts for 4% by weight of organic solvents;

(2) configure the dispersed water phase: 2g gelatin is added to 200ml distilled water, stir to obtain the water phase; the oil-water ratio is 1: 3.3, the dispersant weight is 1% of the water weight, and the emulsifier weight is 0% of the water weight ;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 200r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 57°C and keep stirring for 4h; raise the temperature to 83°C and keep stirring for 3h to end;

(4) Suction filtration and separation of the emulsion with a vacuum filtration device to separate the pellets, and dry them at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle size of 67 μm.

Example 2:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 8.2g of the above-mentioned clean polystyrene foam, add it to 92.75g of methylene chloride, dissolve the polystyrene completely, and stir to obtain the oil phase; the oil phase solute is 100%wt Polystyrene, which accounts for 8.84% by weight of the organic solvent;

(2) configure the dispersed water phase: 8g polyvinyl alcohol, 0.35g sodium dodecylbenzene sulfonate and 0.05g sorbitan oleate are added to 400ml distilled water, and the water phase is obtained by stirring; the oil-water ratio is 1:4, the weight of the dispersant is 2% of the weight of the water, and the weight of the emulsifier is 0.1% of the weight of the water;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 500r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 40°C and keep stirring for 2h; raise the temperature to 60°C and keep stirring for 3h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 80° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 78 μm. As shown in FIG. 2 , it can be seen through a scanning electron microscope that the polystyrene plastic beads obtained in this embodiment have a uniform particle size and a good circularity.

Example 3:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 9g of the above-mentioned foamed plastic, add it to a mixed solvent composed of 61.82g of benzene and 30.93g of 1,2-dichloroethane, dissolve the polystyrene completely, and stir evenly to obtain the oil phase ; The oil phase solute is 100%wt polystyrene, which accounts for 9.7% of the weight of the organic solvent;

(2) Configure the dispersed water phase: add 32g gelatin and 0.4g sodium dodecylbenzenesulfonate to 400ml distilled water, stir well to obtain the water phase; the oil-water ratio is 1: 4.2, and the weight of the dispersant is 8% of the water weight %, emulsifier weight is 0.1% of water weight;

(3) The water phase and the oil phase obtained above are used for emulsifying the SPG membrane with a pore size of 10 μm to prepare an oil-in-water emulsion to obtain a uniformly emulsified emulsion; the emulsion is transferred to a flask, stirred at a rotating speed of 400r/min, and heated to 60°C, keep stirring for 3h; raise the temperature to 80°C, keep stirring for 4h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 22 μm.

Example 4:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 8.2g of the above-mentioned foamed plastics, add it to 92g of chloroform, dissolve the polystyrene completely, and stir it evenly to obtain the oil phase; the oil phase solute is 100%wt polystyrene, which occupies 8.9% by weight of organic solvent;

(2) Configure the dispersed water phase: add 1.2g gelatin and 1.0g sodium dodecylbenzenesulfonate to 1000ml distilled water, stir well to obtain the water phase; 0.12%, emulsifier weight is 0.1% of water weight;

(3) The above obtained water phase and oil phase are emulsified by an SPG membrane with a pore size of 20 μm to prepare an oil-in-water emulsion to obtain a uniformly emulsified emulsion; the emulsion is transferred to a flask, and stirred at a speed of 400 r/min and heated to 60 °C, keep stirring for 3h; raise the temperature to 95°C, keep stirring for 2h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 56 μm.

Example 5:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 9g of the above-mentioned foamed plastic, add it to a mixed solvent consisting of 47g of benzene and 43g of 1,1,1-trichloroethane, dissolve the polystyrene completely, and stir evenly to obtain an oily phase. phase; the oil phase solute is 100%wt polystyrene, which accounts for 10% of the weight of the organic solvent;

(2) Configure the dispersed water phase: add 10g of gelatin and 1.0g of sodium dodecylbenzenesulfonate to 400ml of distilled water, and stir evenly to obtain the water phase; the oil-water ratio is 1:4.2, and the weight of the dispersant is 2.5% of the water %, emulsifier weight is 0.25% of water weight;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 380r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 42°C and keep stirring for 2h; raise the temperature to 75°C and keep stirring for 1h to end;

(4) Separate the emulsion with a centrifuge, collect the lower part of the precipitate, wash with water and then centrifuge, and dry the final centrifuged precipitate at 70°C for 24 hours to obtain a polystyrene plastic pellet with an average particle size of 137 μm. ball.

Embodiment 6:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) configuration oil phase: take by weighing 15g above-mentioned polystyrene foamed plastics, join in by 90g carbon tetrachloride solvent, polystyrene is dissolved completely, stir and make oil phase; Oil phase solute is 100%wt polystyrene Styrene, which accounts for 16.7% by weight of organic solvent;

(2) Configure the dispersed water phase: add 10g of gelatin and 1.0g of sodium dodecylbenzenesulfonate to 400ml of distilled water, stir evenly to obtain the water phase; the oil-water ratio is 1:3.9, and the weight of the dispersant is 2.5% of the water weight %, emulsifier weight is 0.25% of water weight;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 400r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 42°C and keep stirring for 2h; raise the temperature to 75°C and keep stirring for 1h to end;

(4) Separate the emulsion with a centrifuge, collect the lower part of the precipitate, wash with water and then centrifuge, and dry the final centrifuged precipitate at 70°C for 24 hours to obtain a polystyrene plastic pellet with an average particle size of 178 μm. ball.

Embodiment 7:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: Weigh 24g of the above-mentioned foamed plastic, add it to a mixed solvent consisting of 47g of benzene and 43g of 1,1,1-trichloroethane, dissolve the polystyrene completely, and stir evenly to obtain an oily phase. phase; the oil phase solute is 100%wt polystyrene, which accounts for 26.7% of the organic solvent weight;

(2) Configure the dispersed water phase: add 10g of gelatin and 1.0g of sodium dodecylbenzenesulfonate to 350ml of distilled water, stir evenly to obtain the water phase; the oil-water ratio is 1:3.2, and the weight of the dispersant is 2.86% of the water %, emulsifier weight is 0.286% of water weight;

(3) Pour the water phase into a three-necked flask with a condensation recovery tube, and put it into a water bath; adjust the rotating speed to 350r/min, and add the oil phase to the water phase under stirring conditions to obtain evenly emulsified Emulsion; raise the temperature of the water bath to 42°C, keep stirring for 2 hours, raise the temperature to 75°C, and keep stirring for 1 hour to end;

(4) Separate the emulsion with a centrifuge, collect the lower part of the precipitate, wash with water and then centrifuge, and dry the final centrifuged precipitate at 70 ° C for 24 hours to obtain a polystyrene plastic pellet with an average particle size of 288 μm. ball.

Embodiment 8:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 20g of the above-mentioned foamed plastics and add them to 92.75g of carbon disulfide to dissolve the polystyrene completely and stir evenly to obtain the oil phase; the oil phase solute is 100%wt polystyrene, which occupies an organic solvent 21.6% by weight;

(2) configure the dispersed water phase: add 20g polyvinyl alcohol and 4g sodium lauryl sulfate to 400ml distilled water, stir to obtain the water phase; the oil-water ratio is 1: 3.8, and the weight of the dispersant is 5% of the water weight , emulsifier weight is 1% of water weight;

(3) the water phase and the oil phase obtained above are emulsified by an SPG membrane with a pore size of 30 μm to prepare an oil-in-water emulsion to obtain a uniformly emulsified solution; the emulsion is transferred to a flask, stirred at a rotating speed of 400 r/min, and heated to 60°C, keep stirring for 3h; raise the temperature to 95°C, keep stirring for 2h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 73 μm.

Embodiment 9:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 10g of the above-mentioned foamed plastics and add it to a mixed solvent consisting of 62g of benzene and 31g of 1,2-dichloroethane, so that the polystyrene is completely dissolved, and stir evenly to obtain the oil phase; The oil phase solute is 100%wt polystyrene, which accounts for 10.75% of the weight of the organic solvent;

(2) Configure the dispersed water phase: add 7g of polyvinyl alcohol and 0.1g of sodium dodecylsulfonate to 200ml of distilled water, and stir evenly to obtain the water phase; 3.5%, emulsifier weight is 0.05% of water weight;

(3) the water phase and the oil phase obtained above are emulsified by an SPG membrane with a pore size of 30 μm to prepare an oil-in-water emulsion to obtain a uniformly emulsified emulsion; the emulsion is transferred to a flask, stirred at a rotating speed of 400 r/min, and heated to 60°C, keep stirring for 3h; raise the temperature to 95°C, keep stirring for 2h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 86 μm.

Example 10:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: take 10g of the above-mentioned foamed plastic, add it to a mixed solvent composed of 62g of benzene and 31g of 1,2-dichloroethane, dissolve the polystyrene completely, and stir evenly to obtain the oil phase; The oil phase solute is 100%wt polystyrene, which accounts for 10.75% of the weight of the organic solvent;

(2) Configure the dispersed water phase: add 7g of polyvinyl alcohol and 0.1g of sodium dodecylsulfonate to 200ml of distilled water, and stir evenly to obtain the water phase; 3.5%, emulsifier weight is 0.05% of water weight;

(3) the water phase and the oil phase obtained above are emulsified by an SPG membrane with a pore size of 1 μm to prepare an oil-in-water emulsion to obtain a uniformly emulsified emulsion; the emulsion is transferred to a flask, stirred at a rotating speed of 400r/min, and heated to 60°C, keep stirring for 3h; raise the temperature to 95°C, keep stirring for 2h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 3.2 μm.

Example 11:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: weigh 5.6g of the above-mentioned clean polystyrene foam, add it to 92.75g of dichloromethane, stir evenly, add 31.5g of styrene monomer and 0.0063g of benzoyl peroxide, and mix evenly to prepare Obtain an oil phase; wherein the oil phase solute accounts for 40% of the organic solvent weight, the polystyrene weight is 15% of the oil phase solute weight, and the styrene polymerization initiator is 0.02% of the styrene monomer weight;

(2) configure the dispersed water phase: 8g polyvinyl alcohol, 0.35g sodium dodecylbenzene sulfonate and 0.05g sorbitan oleate are added to 400ml distilled water, and the water phase is obtained by stirring; the oil-water ratio is 1: 3.1, dispersant weight is 2% of water weight, emulsifier weight is 0.1% of water weight;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 500r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 40°C and keep stirring for 2h; raise the temperature to 85°C and keep stirring for 5h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 56 μm.

Example 12:

Wash the computer packaging with polystyrene foam and dry it for later use;

(1) Configure the oil phase: Weigh 7.38g of the above-mentioned clean polystyrene foam, add it to 92.75g of dichloromethane, stir evenly, add 0.82g of styrene monomer and 0.0246g of benzoyl peroxide, and mix evenly to prepare Obtain an oil phase; wherein the oil phase solute accounts for 8.84% of the weight of the organic solvent, the weight of polystyrene is 90% of the weight of the oil phase solute, and the initiator for styrene polymerization is 3.0% of the weight of the styrene monomer;

(2) Configure the dispersed water phase: add 8g of polyvinyl alcohol, 0.35g of sodium dodecylbenzenesulfonate and 0.05g of sorbitan oleate into 400ml of distilled water, and stir evenly; the oil-water ratio is 1:4, Dispersant weight is 2% of water weight, and emulsifier weight is 0.1% of water weight;

(3) Pour the water phase into a three-necked flask with a condensation recovery pipe, and put it into a water bath; adjust the rotating speed to 500r/min, and add the oil phase to the water phase under stirring conditions to obtain a uniformly emulsified Emulsion; raise the temperature of the water bath to 40°C and keep stirring for 2h; raise the temperature to 85°C and keep stirring for 5h to end;

(4) The emulsion was separated by suction filtration with a vacuum filtration device, and the pellets were separated, and dried at 70° C. for 24 hours to obtain polystyrene plastic pellets with an average particle diameter of 71 μm.

By contrasting Example 2, Example 11 and Example 12, the formula of the water phase is all the same in these three examples, but the concentration of the oil phase in Example 11 is high, and the oil-water ratio is greater than that of Example 2 and Example 12, from Theoretical analysis if the oil phase raw material adopts polystyrene raw material, then the particle diameter of embodiment 11 will be the largest, but the result shows that the particle diameter of the product obtained in embodiment 11 is small instead, and the main reason is because wherein 85% polystyrene Polymerizable styrene monomers are used.

Comparing Example 2 and Example 12, the oil phase concentration, water phase formulation and oil-water ratio of these two examples are all the same, but what 10% polystyrene in Example 12 adopts is the styrene monomer that can polymerize. Therefore the average particle diameter in embodiment 12 will be smaller than embodiment 2.

Example 13:

Take 400ml of water, add 12g of bentonite (manufacturer: Xuanhua County Dongsheng Chemical Co., Ltd.), stir evenly and place it for at least 24 hours, add 2g of medium-cohesive polyanionic cellulose (PAC, Shandong Yiteng) at a stirring speed of not less than 10000r/min Group), and then add 4g of modified starch (CMS, Bazhou Guangfeng Fine Industrial Auxiliary Co., Ltd.), completely dissolved to obtain drilling fluid. Then add 12g of polystyrene plastic pellets prepared in Example 4. Use a mud cake adhesion coefficient tester (NF~2 mud cake adhesion coefficient tester, Qingdao Haitongda Special Instrument Co., Ltd.) to measure the change of the adhesion coefficient of the drilling fluid before and after the addition of plastic pellets. For the determination method of the adhesion coefficient, see standard Q/ SHCG 4~2011 "Technical Requirements for Lubricants for Water-based Drilling Fluids" 4.2.7 "Reduction rate of mud cake adhesion coefficient". The result shows that the adhesion coefficient of the drilling fluid 5min before adding the polystyrene plastic pellets of the present invention is 0.10, and the adhesion coefficient of the drilling fluid after adding the plastic pellets is 0.03, indicating that the polystyrene plastic pellets of the present invention have good lubrication Effect.

Claims (12)

1. A method for preparing polystyrene plastic pellets, characterized in that said method comprises: (1) The oil phase solute is dissolved in an organic solvent to obtain an oil phase, the oil phase solute is 4 to 40% of the weight of the organic solvent, and the oil phase solute is polystyrene or a mixture of polystyrene and styrene monomer , the weight of polystyrene is 15-100% of the total weight of the oil phase solute, preferably 30-70%; when the oil phase solute contains styrene monomer, an initiator for styrene polymerization is added to the organic solvent , the amount of the initiator for styrene polymerization is 0.02-3% of the weight of styrene monomer, preferably 0.1-0.5%; The solubility parameter of the organic solvent is 8.0-10.2; the solubility in water is less than or equal to 30g/l, and the boiling point is less than 100°C; (2) add dispersant and emulsifier in water and make aqueous phase, dispersant weight accounts for 0.12～8% of water weight, preferably accounts for 1～3% of water weight; Emulsifier weight accounts for 0～1.0% of water weight, Preferably account for 0.1 to 0.3% of water weight; (3) At room temperature, add the oil phase to the water phase, the weight ratio of the oil phase to the water phase is not more than 1:2, preferably 1:3 to 1:7, and perform dynamic dispersion at the same time to obtain a uniformly emulsified emulsion ;Heat the emulsion to 40-60°C, maintain dynamic dispersion for at least 1 hour, then raise the temperature to 60-95°C, maintain dynamic dispersion for at least 0.5 hours, and end; (4) The emulsion is subjected to liquid-solid separation to separate the pellets, and then the pellets are dried to obtain the polystyrene plastic pellets. 2. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: Described organic solvent is benzene, methylene dichloride, trichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, carbon disulfide, 1,1,1-trichloroethane, carbon tetrachloride , one or a combination of cyclohexane. 3. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: The initiator for styrene polymerization is at least one selected from azo initiators, organic peroxy initiators, inorganic peroxy initiators, and oxidation-reduction initiators. 4. the method for preparing polystyrene plastic bead as claimed in claim 3, is characterized in that: The azo initiator includes at least one of azobisisobutyronitrile and azobisisoheptanonitrile; The organic peroxy initiator includes cumene hydroperoxide, tert-butyl hydroperoxide, dibenzoyl peroxide, lauryl peroxide, di-t-butyl peroxide, dicumyl peroxide, At least one of diisopropyl peroxydicarbonate; The inorganic peroxygen initiator includes at least one of potassium persulfate and ammonium persulfate; Described oxidation-reduction initiator comprises water-soluble oxidation-reduction initiator and oil-soluble oxidation-reduction initiator: Wherein the oxidant in the water-soluble oxidation-reduction initiator is selected from at least one of inorganic peroxygen initiators and hydroperoxygen initiators, and the reducing agent is selected from ferrous salts, sodium bisulfite, sodium thiosulfate, at least one of alcohol and polyamine; Wherein the oxidant in the oil-soluble oxidation-reduction initiator is selected from at least one of organic peroxygen initiators, and the reducing agent is selected from at least one of tertiary amine, ferrous naphthenate and mercaptan. 5. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: The dispersant is one or a combination of xanthan gum, gelatin, carboxymethyl cellulose, polyvinylpyrrolidone, hydroxyethyl cellulose, and polyvinyl alcohol. 6. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: Described emulsifier is sodium dodecylsulfonate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sorbitan oleate, sorbitan monostearate, alkylphenol poly One or a combination of oxyethylene ethers. 7. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: In the step (3), the oil phase is added to the water phase and dynamically dispersed to obtain a uniformly dispersed emulsion, and then the emulsion is heated to 43-45°C, and after dynamic dispersion for 1.2-2.5 hours, the temperature is then raised to 65-75°C. Dynamic dispersion ends after 1-2 hours. 8. the method for preparing polystyrene plastic bead as claimed in claim 1, is characterized in that: The polystyrene includes recycled polystyrene waste resin. 9. the method for preparing polystyrene plastic bead as described in any one of claim 1～8, it is characterized in that: The dynamic dispersion in the step (3) is carried out by means of ultrasonic dispersion, SPG film emulsification or stirring. 10. The polystyrene plastic bead product that is made by the method described in one of claims 1-9. 11. polystyrene plastic bead as claimed in claim 10, is characterized in that: The average particle diameter of the pellets is 3-300 μm, preferably 20-100 μm. 12. The application of the polystyrene plastic beads as claimed in claim 10 or 11 in petroleum drilling fluid.

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