JP2007326888A - Emulsified material of plastic and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an emulsified material having fine resin particle diameter of nano order and almost without containing air in the emulsion, and a method for producing the same. <P>SOLUTION: This method for producing the emulsified material is provided by emulsifying an acrylic acid ester polymer or styrene-acrylic acid ester copolymer, making fine particles by a cutting device 3 while swelling the emulsion under a vacuum atmosphere in a vacuum pot 1, at the same time making ≤0.001% air content in the emulsion, then compressing the swollen emulsion made as fine particles while decomposing by a supercritical device S to make hard fine particles and forming the emulsion having 5 to 100 nm particle diameter of the resin particles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plastic emulsion material used as a base material for paints and inks and an additive for plastics, and a method for producing the same.

Recently, water-based emulsions have been attracting attention as pollution-free paints and inks. For example, vinyl emulsion, vinylidene chloride, acrylate esters, and the like can be used as emulsifiers (surfactants), polymerization initiators, and the like. It is adjusted so that particles having a particle size of 0.1 to 0.2 μm are suspended in water by emulsion polymerization using an emulsifier.
JP-A-5-194911

  The resin particle size of such an emulsion is fine enough, but in practice it is condensed, and the particle size becomes 1 μm or more. In order to increase the adhesive force or quick drying property when used in paints and inks, the emulsion It is necessary to further refine the resin particles and the water component.

  Therefore, the emulsion material of the present invention comprises resin particles that form an aqueous emulsion and a water component, and the particle size of the emulsion material is 5 to 100 nm (nanometer), and the air (oxygen) in the emulsion is reduced to 0. 001% or less.

  Also, the method for producing an emulsion material of the present invention comprises swelling resin particles and water components that form an aqueous emulsion while mixing and stirring them in a vacuum atmosphere, cutting and decomposing the resin particles and water components, and then pulverizing them. The resin particles swollen and refined with the critical fluid and the water component were further refined by decomposition and the resin particles were solidified at high pressure.

  When the emulsion material of the present invention is used as a base material for paints and inks, since the particle diameter is 5 to 100 nm, the adhesive force is remarkably increased, and it can be used as a plastic nucleating agent. Since the amount is remarkably small, the flame retardancy is improved and the coating film is not swollen.

  Furthermore, according to the method for producing an emulsion material of the present invention, water and resin particles are swollen and stirred in a vacuum state, and at the same time, they are cut and decomposed, so that emulsion polymerization is reliably performed while reducing these particles. In addition, the air dissolved in the water component can be made 0.001% or less.

  The emulsion according to the present invention comprises 60 to 90% by weight of synthetic resin particles such as aqueous vinyl acetate, vinylidene chloride, and acrylate, and 10 to 40% by weight of water, and the resin particles have a particle size of 5 to 100 nm (nanometers). And the air (oxygen) content in the emulsion is 0.001% or less. In particular, as the resin particles, an acrylate polymer or a styrene-acrylic acid copolymer is preferable, and those which are crosslinked by adding a basic substance such as sodium metasilicate to this component are elastic. Is loaded (synthetic rubber-modified acrylic copolymer). Alternatively, it is possible to use a styrene / butadiene synthetic resin emulsion.

In addition, the acrylic ester polymer or styrene-acrylic ester copolymer having a crosslinked structure sufficiently withstands a supercritical acidic (pH ₂ to 3) atmosphere using CO ₂ and also functions as an adhesive. Therefore, it is most suitable as a base material for paints and inks. Moreover, even if it is used as a base for water-based paints, it is also strong in water resistance after drying.

  In the present invention, even if the water component is as small as 10 to 40% by weight, the particle diameter is as small as 5 to 100 nm, so that the viscosity is low and there is no problem in coating. In addition, when the water component is small as described above, drying is quickened, and there are few harmful effects caused by evaporation of water after application.

  The emulsion according to the present invention is produced as follows.

Monomer composition of water-based synthetic resin particles such as vinyl acetate, vinylidene chloride, synthetic rubber-modified acrylic copolymer, surfactant, polymerization initiator and the like are emulsion-polymerized with a high-speed emulsifier, and the average particle size is 0.3 to Prepare an emulsion consisting of 0.5 μm, solid content of 40-50% and moisture of 50-60% by the usual method (first step), then inject the emulsion into a vacuum kettle and stir and mix under vacuum atmosphere While cutting and decomposing the swollen synthetic resin component and water component while releasing air from the emulsion under vacuum from a cutting and decomposing device such as a mechanical cutting or ultrasonic transmission device that rotates at high speed (0.001% or less) The water clusters and the synthetic resin particles are finely divided (particle diameter 0.1 to 0.2 μm) (second step). At this time, moisture will fly off and the amount of moisture will be adjusted to 10-40%. Next, the emulsion is transferred to a supercritical pressure vessel, and supercritical processing is performed, for example, with CO ₂ at about 200 atm and 40 ° C. At this time, the finely divided but swollen resin particles are further subdivided by the supercritical fluid, and are shrunk and refined by the pressure, and the particle diameter becomes 5 to 50 nanometers (first number) 3 steps).

  In the above method, the three steps are performed in separate devices (high-speed emulsification, vacuum kettle, supercritical device). However, these three steps can be performed in one device. It is also possible to perform the two steps with one device and the second step and the third step with one device.

  The emulsion material thus prepared can be used as it is as a base material for paints and inks, and can also be used as an additive for plastics. The emulsion is nano-order fine particles, and the resin component has a function as an adhesive. Therefore, if the water component of the emulsion is blown away during plastic molding and dispersed in the plastic, the resin component functions as a crystal nucleating agent. In addition, since it acts as a plastic reinforcing agent and is transparent, the amount added can be freely adjusted according to the strength level.

  In addition, aggregation of the emulsion after production becomes a problem. To prevent this aggregation, if an electric field is applied to the emulsion and the resin particles are charged, the particles repel each other and prevent aggregation of the particles. it can. Furthermore, aggregation can be effectively prevented by adding 20 to 30% by weight of pure water after production and allowing the nanoparticles to float.

  Examples will be described below.

  Styrene-acrylic acid ester copolymer (FIGS. 1 and 2) and acrylic acid ester polymer (manufactured by Showa Kogyo) having the molecular structure shown in FIGS. A milky white emulsion was obtained (first step). These emulsions had a resin content of 40-50% by weight and a water content of 50-60% by weight. The pH was 6 to 8, and the viscosity was 1,500 to 4,500 (mPa · S: BH type rotational viscometer).

  The styrene-acrylic acid ester copolymer shown in FIG. 1 has crossed carbon main chains 50, 50, and ester groups COOR 53, 53... 53 and styrene components (benzene rings 52, 52. 52, and bridges 51 and 51 are formed between both main chains 50. This bridge 51 is made of a basic material such as sodium metasilicate, whereby the resin component has elasticity. This resin has good adhesiveness and water resistance, and hardly yellowed even when irradiated with ultraviolet rays.The styrene-acrylic acid ester copolymer shown in FIG. The acrylic acid ester polymer shown in Fig. 3 completely eliminates the benzene ring, which is a styrene component. Only the ester group 53 was integrated into the chain 50, which did not turn yellow at all against ultraviolet rays.The one with such a molecular structure is flame retardant and is exposed to a gas burner. No wrinkles occurred.

  The above-mentioned polymer is cross-linked, and an acrylate ester having this molecular structure can be called a synthetic rubber-modified acrylate ester.

  The emulsion thus prepared is poured into a vacuum kettle 1 as shown in FIG. The vacuum pot 1 has a rotating blade 2 that rotates along the peripheral wall of the vacuum pot for stirring and mixing the emulsion, and the rotating blade 2 slowly stirs the emulsion. Inside the rotary blade 2, there is provided a cutting / disassembling device 3 that rotates at a high speed (1500 rpm) and cleaves and decomposes the water component and the resin component of the emulsion. The device 3 has a rotating shaft 4 that is rotated by a motor M. The rotating shaft 4 has a disk 5 fixed thereto, and cutting blades 6, 6... 6 are erected on the disk 5 at regular intervals. Further, the vacuum pot 1 is provided with a vacuum pump 7. When the inside of the vacuum kettle is evacuated and stirred for about 3 hours, the water component and resin component lubricate, the water component also flies and the water component decreases, and the air (oxygen) mixed in the water also flies and the content is It was 0.001% or less. As a result, the paint using the emulsion increased in nonflammability and no “blowing” when heated. The swelled emulsion was cut with a cutting blade 6 to make the particles fine (0.1 to 0.4 μm) (second step). The swollen particles are easily cut, and the swollen resin particles are easily decomposed even by ultrasonic waves from an ultrasonic transmitter (not shown) instead of the physical cutting blade 6.

Next, the emulsion was further refined (5 to 100 nm) by treatment with a supercritical apparatus S as shown in FIG. When the resin particles are made into nano-order particles in this way, the surface area of the particles is remarkably increased, and a large amount of water is required to be suspended. Therefore, aggregation of 20 to 30% by weight of water can be effectively prevented. The supercritical unit S has a pressure vessel 10, this is the pressure vessel 10 is connected to CO ₂ gas cylinder 11, CO ₂ from the cylinder 11 is raised above 200 atm by pressure pump 12. A stirring device 16 is provided in the pressure vessel 10, and the emulsion is stirred by the device 16. A heater 15 is wound around the pressure vessel 10, and the inside of the vessel is maintained at about 40 ° C. by the heater 15. The When the emulsion was supercritically treated for about 1 hour, the emulsion was completely refined and its viscosity decreased (500 to 2000 mPa · s) (third step). When this was used as a paint, a thin film (1 to 10 μm) was formed, and the film dried quickly and did not adhere to the finger within a few seconds. When this was used for ink, drying was too early and the nozzle was clogged in the case of inkjet spraying, so when 2-3% of antifreeze (ethylene glycol) was added, the nozzle did not clog. This is because the antifreeze liquid coats the periphery of the fine resin particles and delays the evaporation of water. In some cases, ethylene glycol immediately evaporates and promotes the evaporation of water in the particles, so that drying after printing is not delayed.

  Next, a case where the second step and the third step for subjecting the milky white emulsion emulsion-polymerized by the high-speed emulsification device to air removal, atomization, and atomization are performed by a common device will be described.

In FIG. 8, the multifunctional emulsion treatment apparatus 40 has a pressure vessel 41, which can be opened and closed by an opening / closing lid 42, and a stirring and cutting device 43 is provided in the pressure vessel 41. The stirring and cutting device 43 has blades 44, 44... 44 attached to a shaft 70 that rotates at high speed by a motor 71, and the blades 44 include a cutting blade 45. The pressure vessel 41 and the open / close lid 42 are hermetically sealed by engaging with the biting surface 51 of the clamp 47 provided with a plurality of flange inclined surfaces 49 and 50, and the clamp 47 is moved in the horizontal direction by the hydraulic cylinder 48. To do. Connected to the open / close lid 42 are a vacuum pump 52, a CO ₂ cylinder 53, and a pressurizing pump 54 for pressurizing CO ₂ therein to 200 atm or more. A coil 55 is wound around the peripheral wall of the pressure vessel 41, and a plasma wave transmitter 56 is connected to the coil 55, and a current having a frequency of 135000 Hz is applied to the coil 55 from the transmitter 56. As a result, a magnetic field along the peripheral wall of the pressure vessel 41 is generated, and an electric field having a circumferential electric force line is applied to the pressure vessel. This electric field is applied to the emulsion liquid in the pressure vessel 41 in the circumferential direction. give.

  Further, a temperature adjusting device 57 is provided outside the coil 55, and this device may be a jacket through which the temperature-controlled liquid medium passes or a heater. An ultrasonic transducer 60 faces the bottom wall of the pressure vessel 41, and an ultrasonic transmitter 61 is connected to the transducer 60.

  The emulsion prepared in the first step is injected into the pressure vessel 41 by opening the opening / closing lid 42, and after closing the opening / closing lid 42, the inside of the pressure vessel is evacuated by the action of the vacuum pump 52, and water and the resin component are removed. It swells and air evaporates from the emulsion, and part of the water evaporates. At this time, the stirring and cutting device 43 is driven, and the blades 44 and the cutting blade 45 rotate together with the shaft 70 (1500 rpm) to cut and swell the swollen resin component. At this time, the swollen resin component may be decomposed by operating the ultrasonic transmitter 60. Further, the coil 55 is operated, and the stirring effect is increased by the plasma wave.

  A supercritical process is performed after opening the valve which is not shown in figure and exhausting the water vapor | steam and air which came out of emulsion from the pressure vessel. That is, the pressure of CO 2 from the cylinder 53 is increased to 200 atm or higher by the pressure pump 54 and sent into the pressure vessel 41. At this time, a plasma wave (operation of the coil 55) is applied in order to produce a stirring effect, and the cutting and stirring device 43 and the ultrasonic device are driven to produce a cutting and decomposing effect of the swelled and refined resin component. . Note that either a plasma wave device or an ultrasonic device may be selectively used (may be selective in any of the steps of air removal, atomization, and atomization).

  Furthermore, since the emulsion nano-sized through the third step aggregates with time, it is immediately stored in the electric field device 20 as shown in FIG. The electric field device 20 has a power source 21, and an electrode 22 insulated by an insulating box 24 is connected to the power source 21. An emulsion container 23 is placed on the electrode 22, and emulsion particles in the container are placed. Are charged and the charged particles repel each other to prevent their aggregation. From the power source 21, a voltage of 10V to 1KV is applied to the electrode plate 22, and a pulse current having a frequency of 11Hz to 50KHz as shown in FIG.

  The emulsion material of the present invention can be used not only as a base for paints and inks, but also can be reinforced as an additive for plastics and has high adhesiveness. It can be used as a material or for forming containers and trays for food.

It is a molecular structure figure of the styrene-acrylic acid ester copolymer of this invention. It is the molecular structure figure of the other styrene-acrylic acid ester copolymer of this invention. 1 is a molecular structure diagram of an acrylate polymer of the present invention. It is a schematic block diagram of the vacuum pot in the case of vacuum-processing the emulsion material of this invention. It is a schematic block diagram of the supercritical apparatus in the case of carrying out the supercritical process of the emulsion material of this invention. It is the schematic of the electric field apparatus for preventing the aggregation of the processed emulsion material. It is a wave form diagram of the electric field apparatus of FIG. It is a schematic block diagram of a multifunction processing apparatus.

Explanation of symbols

1 ... vacuum pan 2 ... rotary blade 3 ... cutting device 6 ... cutting blade 10 ... pressure vessel 11 ... CO ₂ cylinder 16 ... stirrer 20 ... field device 21: Power supply 22 ... electrode plate 30 ... pulse current 40 ... multifunction processor

Claims (2)

  An emulsion material comprising resin particles forming an aqueous emulsion and a water component, wherein the resin particle diameter is 5 to 100 nm, and the air content in the emulsion is 0.001% by weight or less.   Resin particles that form an aqueous emulsion and a water component are swollen while being mixed and stirred in a vacuum atmosphere, and then cut or decomposed into fine particles, and then the resin particles and water components that have been swollen and fined with a supercritical fluid are combined. A method for producing an emulsion material, in which fine particles are formed by pressing and solidifying under high pressure while further decomposing.

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