KR100694460B1 - Method for Manufacturing Rubber Grafted Copolymer Powder - Google Patents

Abstract

The present invention is a rubber-containing graft copolymer powder, characterized in that the rubber-based graft copolymer latex by blending and dispersing 1 to 10 parts by weight of the colloid-type modifier on a solids basis, and then spray-drying, based on solids It provides a method of manufacturing.

The production method of the rubber-containing graft copolymer powder of the present invention improves the caking resistance of the prepared powder without reducing the impact resistance and reduces the deposits generated in the device during operation, thereby reducing the risk of fire and dust. It reduces the risk of explosion and increases the yield.

Rubber-containing graft copolymer, spray drying method, colloidal modifier, caking resistance, impact resistance

Description

Method for manufacturing rubber-containing graft copolymer powder {Method for Manufacturing Rubber Grafted Copolymer Powder}

1 is a schematic view showing an apparatus for producing rubber-containing graft copolymer powder.

Brief description of the main symbols in the drawings

10: Colloid mixed latex supply line

20: spray dryer body (drying chamber)

30: atomizer

40 cyclone

50: bag filter

60: exhaust air line

70: drying powder line

The present invention relates to a method for preparing rubber-containing graft copolymer powder.                         

Rubber-containing graft copolymers are generally used as modifiers to reinforce the impact of hard plastics such as polyvinyl chloride (PVC). As a manufacturing method of such a rubber-containing graft copolymer, it can be roughly divided into a coagulation method and a spray drying method.

In the coagulation-coagulation method, first, when an aqueous solution of a coagulant such as an inorganic salt or an acid is added to the polymer latex to break the electrostatic stabilization formed by the emulsifier, the polymer particles in the latex are agglomerated by charge neutralization, which is called floc. Call. However, since these flocs do not form a physical bond and form a kind of multi-particle assemblage, in such a state, break-up may easily occur due to a disturbing flow by an external impeller. Therefore, as a next step of flocculation, the aging process is performed to increase the strength of the flocs. This stage of aging is carried out at high temperatures, in which flocs form a single particle of some strength due to interchain interpenetration.

Another method, the spray drying process, utilizes a pressure nozzle or rotary wheel to inject a polymer latex into a droplet of 40-200 μm in a dryer operated at high temperature by hot air. It is a method of dispersing water into droplets and immediately removing the water present in the droplets using hot air and recovering it in powder form. Such a spray drying method is a method used in a variety of food, ceramics, as well as polymer. In the case of such a spray drying method, unlike the coagulation agglomeration method, the facility has a simple and convenient operation.

On the other hand, as part of efforts to improve the impact strength in recent years, a study to gradually increase the rubber content in the rubber-containing graft copolymer has been conducted. However, as the rubber content in the rubber-containing graft copolymer increases, in the case of spray drying under high temperature operating conditions, high rubber content tends to cause deposits in the device, thereby increasing the risk of fire and dust explosion. There is a problem such as a decrease in yield and a decrease in productivity due to inoperability for a long time.

In order to solve the above problems of the prior art, the present invention provides a rubber-containing graft copolymer powder that can improve caking resistance and reduce deposits occurring in the device during operation by using a colloidal modifier. An object of the present invention is to provide a manufacturing method.

In order to achieve the above object, the present invention is a rubber-containing graft, characterized in that the rubber-based graft copolymer latex by blending and dispersing 1 to 10 parts by weight of a colloidal modifier on a solids basis and then spray-drying It provides a method for producing a copolymer copolymer powder.

In the production method of the present invention, the rubber content of the rubber-containing graft copolymer latex is characterized in that 80% or more.

Moreover, in the manufacturing method of this invention, the average particle diameter of a colloidal modifier is 10 nm or more and 100 nm or less, It is characterized by the above-mentioned.

In addition, in the production method of the present invention, the colloidal modifier is characterized in that at least one member selected from the group consisting of silica, calcium carbonate and a hard inelastic copolymer having a glass transition temperature of 50 ℃ or more.

Hereinafter, the present invention will be described in detail.

The present invention can use a polymer latex prepared by conventional emulsion polymerization. However, it is preferable to use a polymer latex having a rubber content of 80% or more.

The rubber-containing graft copolymer is composed of a seed, a core, and a shell.

First, the seed and the core are rubber constituents of alkyl acrylates having 1 to 8 carbon atoms, that is, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate and hexyl. An acrylate, octyl acrylate, 2-ethylhexyl acrylate, etc. are used, and can also be used individually or in combination of 2 or more types.

Alkyl methacrylate having 1 to 4 carbon atoms of an alkyl group is used as the cell-forming monomer, and specifically, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, and the like. Use In addition, ethyl acrylate, methyl acrylate, butyl acrylate or the like may be added to control the glass transition temperature of the cell component.                     

Emulsifiers include ionic emulsifiers, such as saturated or unsaturated fatty acid potassium salts, potassium oleate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and 0.1 to 4.0 based on 100 parts by weight of the total monomer used in the polymerization reaction. The use of parts by weight is preferred.

Examples of the polymerization initiator include ammonium persulfate, potassium persulfate, benzoyl peroxide, azobisbutylonitrile, butyl hydroperoxide, and the like, and 0.1 to 3.0 parts by weight based on 100 parts by weight of the total monomer used in the polymerization reaction. Can be used as a wealth.

Crosslinking agents include 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, allyl acrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene Examples thereof include glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, and the like, and may be used in an amount of 0.5 to 5.0 parts by weight based on 100 parts by weight of the total monomer used in the polymerization reaction.

The rubber component constituting the sheath and the core of the polymer latex resin comprises 80 to 99.5% by weight of the total polymer, the shell is 0.5 to 20% by weight of the total component.

The polymerization process for preparing the rubber-containing graft copolymer of the present invention will be described in more detail as follows.

1) One Step Reaction-Seed Preparation

The seed is 95.0 to 99.5 parts by weight of alkyl acrylate having 1 to 8 carbon atoms, 0.5 to 5.0 parts by weight of crosslinking agent, 0.1 to 3.0 parts by weight of polymerization initiator, and emulsifier 0.1 to 100 parts by weight of the total of monomers used for the polymerization reaction. A mixture comprising from 4.0 parts by weight to 1,000 parts by weight of ion-exchanged water is prepared by crosslinking at a temperature of 60 to 80 ° C.

2) Two Stage Reaction—Core Preparation

The core has 95.0 to 99.5 parts by weight of alkyl acrylate having 2 to 8 carbon atoms, 0.5 to 5.0 parts by weight of crosslinking agent, 0.1 to 4.0 parts by weight of emulsifier and ion exchanged water with respect to 100 parts by weight of the total monomer used in the polymerization reaction. After the mixture containing 80 parts by weight is prepared in a pre-emulsion state, the emulsion is continuously added to the seed prepared in step 1), while 0.1 to 3.0 parts by weight of the polymerization initiator is added and polymerized.

3) Three Step Reaction—Preparation of Shell

The shell is 90 to 100 parts by weight of alkyl methacrylate selected from the group consisting of alkyl methacrylates having 1 to 4 carbon atoms of the alkyl group, based on 100 parts by weight of the monomers used in the polymerization reaction, ethyl acrylate, methyl acryl After preparing a composition mixture containing 0 to 10 parts by weight of alkyl acrylate selected from the group consisting of late and butyl acrylate, 0.1 to 4.0 parts by weight of emulsifier and 150 parts by weight of ion-exchanged water, the emulsion was prepared. While continuously input to the secondary polymer prepared in step 2) is prepared by adding 0.1 to 3.0 parts by weight of polymerization initiator and polymerization.

In the case of the latex resin to which the present invention is to be applied, due to the property that the rubber phase of the constituents contains more than 80%, a large number of adhesions in the device are generated as well as agglomeration between particles during the drying process. This can be thought to be due to the adhesion of the components of the rubbery phase with low glass transition temperature to each other during the high temperature drying process.

Therefore, in order to improve such a phenomenon, a certain amount of powder such as calcium carbonate (CaCO ₃ ) or silica (SiO ₂ ) is added as a fine powder modifier to surround particles of latex resin to prevent aggregation between components having low glass transition temperature. Can be. In the case of such a fine powder modifier, the particle size is about 10 to 100 nm. Such fine powder modifiers may be introduced by negative pressure into the ceiling or side portions of the dryer using a powder feeder, or may be introduced by using a pipe at the rear of the heater. However, when a large amount is added, the fine powder particles passing through the cyclone easily block the bag filter, thereby providing a cause that makes long operation impossible and also a large amount of the powder. The degree of improvement in caking and adhesion in the device is minimal.

Therefore, separately from 1 to 10 parts by weight of the colloid (colloid) modifier on the basis of solids and dispersed in 100 parts by weight of polymer latex resin on a solid basis separately. As the colloidal modifier used therein, silica (SiO ₂ ), calcium carbonate (CaCO ₃ ), and hard inelastic copolymers having a high glass transition temperature (Tg) of 50 ° C. or more may be used. The particle size of the colloidal modifier is preferably between 10 and 100 nm. If the particle size is 10 nm or less, it is difficult to effectively separate the surface between the powders of the rubber-containing graft copolymer during storage, and if the particle size is larger than 100 nm, the rubber-containing graft It is difficult to expect improvement of powder properties because the surface area that can surround the powder of the (graft) copolymer as a whole is reduced. In addition, the solid content ratio (TSC) of the colloidal modifier is preferably 30 to 60%. If the solid content of the colloidal modifier is too low, less than 30%, the operating cost of the spray drying method increases. If the content is too high, the colloidal particles are not completely dispersed. It is difficult to expect the improvement of powder characteristics because they may be aggregated together.

The latex resin in which such a colloidal modifier is dispersed is converted into powder phase through a spray drying process. Spray methods that can be used in the spray drying process include a pressure nozzle method and a rotary wheel method. The polymer latex, which has undergone such a spraying method, is produced as a spherical particle having a size of 40 ~ 200㎛. Such spherical particles are removed from the moisture and converted into a powder while passing through the high temperature dry air. The inlet temperature of the dry air is preferably 150 to 250 ° C, and in the case of the outlet temperature, 40 to 90 ° C. The shape of the spherical particles is a major requirement to improve the flowability of the resin, and the particles having the characteristics of improving the apparent specific gravity are produced by the characteristics that little voids occur in the interior of the drying process.

Hereinafter, the present invention will be described in more detail through the following Preparation Examples and Experimental Examples, but the scope of the present invention is not limited to the Preparation Examples and Experimental Examples.

Hereinafter, the physical properties of the rubber-containing graft copolymer dry powder were evaluated as follows.

[Caking resistance]

In order to measure the caking resistance of the manufactured dry powder, 20 g of the dried powder was put in a cylindrical container manufactured by itself, and left for 2 hours under a load of 40 kg. The cake obtained was then subjected to an electronic vibrator. The degree of cake collapse was measured while shaking for 150 seconds.

Attachment in the device

The yield was measured to evaluate the attachment state inside the apparatus. When the yield was high, it was judged that the degree of adhesion in the apparatus was small.

[Impact strength]

Impact strength was investigated using a dry powder. To evaluate the physical properties of the impact modifier 100 parts by weight of polyvinyl chloride resin (PVC), 4.0 parts by weight of heat stabilizer (DLP), 0.9 parts by weight of calcium stearate (Ca-St), 1.36 parts by weight of polyethylene wax (PE Wax), 1.0 part by weight of processing aid (PA-821 manufactured by LG Chemical), 5.0 parts by weight of CaCO ₃ , and 4.0 parts by weight of TiO ₂ were added to a mixer at room temperature, followed by mixing while raising the temperature to 115 ° C. at 1,000 rpm. After reaching 115 ° C., the temperature was lowered to 400 rpm and cooled to 40 ° C. to complete the master batch butyl acrylate. 7 parts by weight of each dry powder produced through the spray drying process was added to the master batch, and then milled at 190 ° C. for 7 minutes using a roll mill to form a 0.6 mm sheet. The sheet was cut to a size of 150 mm x 200 mm and then the milling rectangle was laminated to a mold of 3 mm x 170 mm x 220 mm. A specimen of 3 mm thickness was prepared by preheating (0.5Kg) for 8 minutes, compressing (10Kg) for 4 minutes, and cooling (10Kg) for 3 minutes using a 190 ° C. heating press. The specimens made as described above were exquisitely cut according to ASTM D-256 standard to make impact specimens and then measured the Izod impact strength. The impact strength was measured at 23 ° C. and 0 ° C. at room temperature.

Production Example

(Preparation of rubber-containing graft copolymer)

(1) One Step Reaction-Seed Preparation

In a step of polymerizing a seed, 339.8 g of ion-exchanged water was introduced into the reactor, and the temperature was raised to 70 ° C. 49.85 g of butyl acrylate and allyl methacrylate when the temperature of ion-exchanged water reaches 70 ° C 0.05 g, 1,3-butanediol dimethacrylate, and 0.1.g g of sodium lauryl sulfate (SLS) were added at once. The seed was polymerized by adding 26.77 g (1% by weight) of potassium persulfate while maintaining the temperature in the reactor at 70 ° C.

(2) Two Step Reaction—Core Preparation

Polymerizing the core rubber layer, 208.4 g of ion-exchanged water, 448.66 g of butyl acrylate, allyl methacrylate 0.450 g, 1,3-butanediol dimethacrylate 0.90 g, 74.68 g (3% by weight solution) of sodium lauryl sulfate were mixed to form a pre-emulsion. After the stabilized pre-emulsion was made, the seed latex produced in the first step reaction was continuously added for 1 hour and 30 minutes at a constant flow rate. At the same time, 149.34 g (1% by weight) of potassium persulfate was continuously added for 1 hour and 30 minutes to proceed with the polymerization. And it aged for 1 hour at 70 ℃ reaction temperature to complete the core portion.

(3) Three Step Reaction-Shell Preparation

Polymerizing the shell portion to the core portion made up to step 2, firstly, a preemulsion of 197.5 g of ion-exchanged water, 117.75 g of methyl methacrylate, 9.25 g of ethyl acrylate, and 13.8 g of sodium lauryl sulfate (3% by weight solution) made. Pre-emulsion and potassium persulfate 69.2g (1% by weight solution) were added to the latex up to two stages at the same time for 1 hour to proceed with the reaction of the shell portion. Likewise, the polymerization was completed by aging for 1 hour while maintaining a constant temperature in the reactor at 70 ℃.

Experimental Example 1

(1) Blending polymer latex with colloidal silica

100 parts by weight of the polymer latex (based on the solids) and the colloidal silica prepared in the preparation example were blended by varying the mixing ratio (based on the solids) as shown in Table 1, and the colloidal silica had the particle size of 20 nm. It was made constant.

(2) Preparation of rubber-containing graft copolymer dry powder

The spraying method of the rotary wheel was used, and the rotational speed of the rotary wheel was 20,000 RPM. The amount of latex blended above was 24 L / hr. As the fine powder modifier, 2 parts by weight of calcium carbonate having a particle size of 40 nm was used, and a powder feeder was used to feed a negative pressure into the ceiling of the dryer. The dryer inlet temperature was maintained at 190 ° C, and the outlet temperature at that time was maintained at 67 ° C.

The caking ratio, yield, and impact strength of the rubber-containing graft copolymer dry powder obtained above were measured and listed in Table 1.

Caking Yield Impact Strength [㎏ · f-m / m] Room temperature Low temperature Colloidal silica input amount: 2.5 parts by weight 20% 82% 30.7 22.6 Colloidal silica input amount: 5 parts by weight 5% 90% 31.7 22.1 Colloidal silica input amount: 10 parts by weight One% 95% 30.1 21.7 Colloidal Silica Input: 0 parts by weight 70% 70% 31.2 22.5 Colloidal silica dose: 0.5 parts by weight 43% 78% 31.3 22.3 Colloidal silica dosage: 15 parts by weight 0% 98% 28.5 20.1

As shown in Table 1 above, when the colloidal modifier was added, the caking resistance was improved and the adhesion in the device was reduced. In particular, when the input amount is less than 1 part by weight, the effect of improving the caking resistance is reduced, and when the input amount is used in excess of 10 parts by weight, it can be seen that a problem occurs that the impact strength is lowered.

Experimental Example 2

The colloidal silica was sprayed through the pressure nozzle separately without blending with the polymer latex prepared in the preparation example and dried simultaneously with the polymer latex prepared in the preparation example. The pressure of the pressure nozzle was 3KG. The colloidal particle size used was 20 nm.

The caking ratio, yield, and impact strength of the resulting rubber-containing graft copolymer dry powder were measured. As shown in Experiment 1, the colloidal loading was 5 parts by weight (particle size was 20 nm) and blended was obtained. It is shown in Table 2 compared with the measurement results for the graft copolymer dry powder.

Caking Yield Impact Strength [㎏ · f-m / m] Room temperature Low temperature When spraying through pressure nozzle individually 60% 68% 29.9 21.7 When blending after adding colloidal silica at the ratio of 5 parts by weight 5% 90% 31.7 22.1

In the case of the rubber-containing graft copolymer dry powder obtained by adding and blending a colloidal modifier as shown in Table 2, the powder is dried at the same time as the polymer latex prepared in the preparation by spraying through a pressure nozzle separately. Caking resistance was remarkably superior to that in the case, and the adhesion in the apparatus was reduced.

Experimental Example 3

100 parts by weight (based on solids) of the polymer latex prepared in the preparation example and 5.0 parts by weight (based on solids) of colloidal silica were blended, and the particle sizes of the colloidal silica were blended as shown in Table 3, respectively. .

In addition, a rubber-containing graft copolymer dry powder was prepared in the same manner as in Experimental Example 1, and the caking ratio, yield, and impact strength of the rubber-containing graft copolymer dry powder were measured. It is shown in Table 3.

Caking Yield Impact Strength [㎏ · f-m / m] Room temperature Low temperature Colloidal Silica Particle Size: 5nm 25% 82% 30.9 22.0 Colloidal Silica Particle Size: 10nm 14% 85% 31.3 21.9 Colloidal Silica Particle Size: 20nm 5% 90% 31.7 22.1 Colloidal Silica Particle Size: 50nm 11% 88% 31.0 22.3 Colloidal Silica Particle Size: 120nm 27% 82% 30.9 22.1 Colloidal Silica Particle Size: 200nm 40% 80% 30.7 21.9

As shown in Table 3 above, when the colloid-type modifier was added, the particle size of the colloid-type modifier was improved between 10 and 100 nm.

As described above, the rubber-containing graft copolymer powder production method of the present invention improves the caking resistance of the prepared powder without deteriorating impact resistance and reduces the risk of fire by reducing deposits generated in the device during operation. And reducing the risk of dust explosion and increasing the yield.

Claims (4)

A method for producing a rubber-containing graft copolymer powder, characterized in that it is spray-dried after dispersing by blending 1 to 10 parts by weight of a colloidal modifier based on solids to 100 parts by weight of rubber-containing graft copolymer latex on a solids basis. 2. The method for producing a rubber-containing graft copolymer powder according to claim 1, wherein the rubber-containing graft copolymer latex has a rubber content of 80% or more. The method for producing a rubber-containing graft copolymer powder according to claim 1, wherein the average particle diameter of the colloidal modifier is 10 nm or more and 100 nm or less. The method for producing a rubber-containing graft copolymer powder according to claim 1, wherein the colloidal modifier is at least one member selected from the group consisting of silica, calcium carbonate and a hard inelastic copolymer having a glass transition temperature of 50 ° C or higher. .

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