KR101515674B1 - ABS Graft Resin Having Superior Heat Resistance And Method For Preparing The Same - Google Patents

Abstract

More particularly, the present invention relates to an ABS grafted resin containing an inorganic acid and a metal stearate salt, and a process for producing the ABS grafted resin.
According to the present invention, it is possible to provide an ABS graft resin excellent in stability at the time of injection and excellent in color and thermal stability even after processing and a method for producing the ABS graft resin.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ABS graft resin having excellent thermal stability,

More particularly, the present invention relates to an ABS graft resin excellent in stability at the time of injection and excellent in color and thermal stability even after processing, and a method for producing the ABS graft resin.

ABS grafted resin is generally produced by emulsion graft polymerization of styrene and acrylonitrile in butadiene rubber, and is excellent in impact resistance, processability, and chemical resistance, and thus is widely used in housings, home appliances, office equipment, and automobile parts .

However, the use of ABS grafted resins is limited to electronic parts and automobile interiors that require heat resistance due to thermal deformation at prolonged exposure at high temperatures.

In order to improve the poor heat resistance of the ABS graft resin as described above, styrene is generally replaced by? -Methylstyrene having a glass transition temperature of 165 占 폚. However, There is a problem that the resin is discolored by the residual? -Methylstyrene monomer or silver streaks are generated in the flow direction of the resin in the flow direction, and the manufacturing cost is increased and the economical efficiency is lowered.

In order to solve the problems of the prior art as described above, it is an object of the present invention to provide an ABS graft resin excellent in stability at the time of injection and excellent in color and thermal stability even after processing and a method for producing the ABS graft resin.

These and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides an ABS grafted resin containing an inorganic acid and a metal stearate salt, and a process for producing the ABS grafted resin.

As described above, according to the present invention, there is provided an ABS graft resin excellent in stability at the time of injection and excellent in color and thermal stability even after processing and a method for producing the ABS graft resin.

Hereinafter, the present invention will be described in detail.

The ABS graft resin of the present invention is characterized by containing inorganic acid and metal stearate salts.

The ABS (acrylonitrile-butadiene-styrene) graft resin can be prepared by introducing an aromatic vinyl monomer and a vinyl cyan monomer into a rubber latex and graft-polymerizing the same.

The rubber latex may be selected from the group consisting of butadiene rubber (BR), ethylene-propylene-diene monomer rubber (EPDM), ethylene-propylene rubber (EPR), halobutyl rubber, butyl rubber, styrene-isoprene- Rubber (SBR) may be selected and used.

The rubber latex may be a rubber latex having an average particle size of 0.1 to 0.4 탆, specifically a rubber latex having an average particle size of 0.08 to 0.16 탆 and a gel content of 65 to 95% by weight, an average particle size of 0.26 to 0.34 탆, A rubber latex having a content of 55 to 85% by weight or a rubber latex having an average particle size of 0.26 to 0.34 탆 and a gel content of 25 to 35% by weight, or the like, or a mixture of two or more thereof.

The rubber latex is preferably contained in an amount of 40 to 70% by weight based on the total amount of the rubber latex and the monomer. When the content is less than 40% by weight, the rubber latex is not preferable from the viewpoint of cost and grafting efficiency. , There is a problem that the grafting is not effectively performed and the physical properties are deteriorated.

The aromatic vinyl monomer may be styrene, alpha methyl styrene, alpha ethyl styrene, para methyl styrene, vinyl toluene, derivatives thereof, or the like.

The vinyl cyan monomer may be acrylonitrile, methacrylonitrile, ethacrylonitrile, derivatives thereof, or the like.

It is preferable that the aromatic vinyl monomer and the vinyl cyan monomer are contained in a weight ratio of 16: 84 to 24:76. Within this range, the effect of preventing the physical properties such as glossiness from being mixed with the SAN (styrene-acrylonitrile) have.

In addition to the above aromatic vinyl monomers and vinyl cyan monomers, there may be mentioned maleimide, N-methyl maleimide, N-ethyl maleimide, N-propyl maleimide, N-phenyl maleimide, methyl methacrylate, methyl acrylate, butyl acrylate, , Maleic anhydride, or a mixture thereof, may be further included. At this time, the vinyl monomer is used in a small amount, preferably 1 to 10% by weight based on the total amount of the monomers.

The inorganic acid is preferably sulfuric acid or hydrochloric acid, more preferably sulfuric acid.

The inorganic acid is preferably contained in an amount of 0.5 to 3.0% by weight, more preferably 1.0 to 2.0% by weight based on the ABS graft resin. Within this range, stability of the ABS polymer powder and ABS graft resin, Excellent color and thermal stability.

The metal stearate salt is preferably magnesium stearate, calcium stearate or a mixture thereof, more preferably magnesium stearate. In this case, the ABS styrene salt has excellent color and thermal stability.

The metal stearate salt is preferably contained in an amount of 0.8 to 3.0% by weight, more preferably 1.2 to 2.0% by weight based on the ABS graft resin. Within this range, the color of the ABS graft resin and / There is an excellent effect of thermal stability.

It is preferable that the ABS graft resin further contains 0.5 to 5.0% by weight, preferably 1.0 to 2.0% by weight, of carboxylic acid. Within this range, it is possible to assist kneading in the screw during injection molding, To minimize the color change by reducing the amount of resin that receives locally high heat.

The carboxylic acid is preferably a fatty acid, a rosin acid, or a mixture thereof.

The carboxylic acid may be formed by a neutralization reaction between a carboxylate emulsifier and an acid flocculant, and the fatty acid and rosin acid may be produced by neutralizing a fatty acid soap and a rosin acid alkali salt with an acid flocculant.

The ABS graft resin is preferably prepared by emulsion polymerization.

The process for preparing the ABS grafted resin of the present invention comprises an emulsion graft polymerization step, an aggregation step of a polymer latex, and a processing step, wherein an inorganic acid is used as a flocculating agent, and the processing step is a step of adding a metal stearate salt .

The emulsion graft polymerization may be carried out by adding an emulsifier, a molecular weight modifier, a polymerization initiator, and ion exchange water, which are generally used in the production of ABS graft resins.

The emulsifier is preferably a carboxylate emulsifier, more preferably a fatty acid soap or an alkali salt of a rosin acid, and the amount thereof is preferably 0.2 to 2 parts by weight based on 100 parts by weight of the total amount of the rubber latex and the monomer .

The molecular weight regulator is preferably tertiary dodecyl mercaptan, and the content thereof is preferably 0.2 to 0.6 parts by weight based on 100 parts by weight of the rubber latex and the monomers.

The polymerization initiator may be a peroxide such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, or persulfate; A redox catalyst such as sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, sodium pyrophosphate, sodium sulfite, and the like.

The polymerization initiator is preferably added in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total of the rubber latex and the monomer.

The ion-exchanged water is preferably added in an amount of 100 to 400 parts by weight based on 100 parts by weight of the rubber latex and the monomers.

The monomers may be administered to the polymerization reactor in a batch, multistage, or continuously. Particularly, it is preferable that the monomers are divided into multiple steps or continuously administered in order to improve the grafting rate and minimize the formation of the coagulated product.

The above-mentioned emulsion graft polymerization is not particularly limited if it is a reaction condition that can be applied in the production of ABS graft resin, but it is preferably carried out at a temperature of 45 to 80 ° C for 3 to 5 hours.

The polymer latex prepared in the emulsion graft polymerization step preferably has a graft rate of 25 to 65%.

The coagulation step of the polymer latex includes an aging process after agglomeration of the polymer latex, followed by a centrifugal dehydration with clean water, and a pre-process of recovering the powder through a drying process by a fluidized bed.

The polymer latex is agglomerated with an inorganic acid flocculant, aged at a predetermined temperature, and then subjected to centrifugal dehydrator or the like to remove low molecular weight substances remaining in water and water, And can be recovered as a powder through a drying process.

The inorganic acid flocculant is preferably sulfuric acid or hydrochloric acid, more preferably sulfuric acid.

The inorganic acid flocculant is preferably used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the polymer latex. When the content of the inorganic acid flocculant is less than 1 part by weight, agglomeration is not effectively performed. There is a problem that the manufacturing cost is increased due to excessive use of the flocculant.

The agglomeration is preferably carried out at a temperature of 70 to 90 ° C, and the aging is preferably carried out at a temperature of 90 to 95 ° C.

The processing step preferably comprises an extrusion step and an injection step.

The metal stearate salt to be added to the processing step is preferably magnesium stearate, calcium stearate or a mixture thereof, more preferably magnesium stearate. In this case, the metal stearate salt is excellent in both color and thermal stability .

The metal stearate salt may be added in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the dried ABS resin powder.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example  One

< Graft  Copolymer production>

20 parts by weight of a rubber latex having an average particle size of 0.095 占 퐉 and a gel content of 83% by weight, 35 parts by weight of a rubber latex having an average particle diameter of 0.31 占 퐉 and a gel content of 75% by weight, 120 parts by weight of ion- 3.0 parts by weight of acrylonitrile, 12 parts by weight of styrene, 0.5 part by weight of potassium rosinate, and 0.1 part by weight of tertiary dodecyl mercaptan were charged, and the reaction temperature was raised to 45 캜. When the temperature inside the reactor reached 45 ° C, 0.1 part by weight of tertiary butyl hydroperoxide, 0.25 parts by weight of an activator composed of dextrose, sodium pyrophosphate and ferrous sulfate was added to the reactor to initiate the polymerization reaction , And the reaction temperature was raised to 70 DEG C for 60 minutes. The polymerization conversion rate at this time was 73%.

In a separate mixing apparatus, 6 parts by weight of acrylonitrile, 24 parts by weight of styrene, 25 parts by weight of ion-exchanged water and 1.2 parts by weight of potassium rosinate were mixed to prepare a monomer emulsion, which was then continuously introduced into the reactor for about 2 hours Respectively. At the same time, 0.15 part by weight of tertiary butyl hydroperoxide was added continuously into the reactor for about 2 hours. At this time, the reaction temperature was maintained at 70 占 폚.

After the addition of the monomer emulsion, 0.12 parts by weight of an activator composed of dextrose, sodium pyrophosphate, and ferrous sulfate and 0.05 part by weight of tertiary butyl hydroperoxide were fed into the reactor, After the temperature was raised to 80 ° C over 1 hour, the reaction was terminated to prepare an ABS polymer latex. At this time, the polymerization conversion was 99%.

<Agglomeration and Aging>

To the prepared ABS polymer latex, 1.8 parts by weight of sulfuric acid was added as an aggregating agent, agglomerated at 70 DEG C, aged at 90 DEG C, dehydrated and dried to obtain an ABS polymer powder.

<Melting Kneading >

The resulting ABS polymer powder and SAN resin were mixed at a ratio of 25:75 and then mixed with 2.0 parts by weight of solid magnesium stearate to prepare a pellet at 200 ° C using a twin screw extruder. The pellet was again injected to prepare a physical specimen Respectively.

Comparative Example  One

The procedure of Example 1 was repeated except that 2.3 parts by weight of magnesium sulfate was used instead of the aqueous solution of sulfuric acid as the coagulant in Example 1 and magnesium stearate according to the present invention was not added during processing.

Comparative Example  2

The same procedure as in Example 1 was carried out except that magnesium stearate according to the present invention was not added during processing in Example 1 above.

[Test Example]

Properties of the ABS polymer powder (before processing) and the ABS (after processing) resin specimen prepared in Example 1 and Comparative Examples 1 and 2 were measured by the following methods, and the results are shown in Table 1 below .

Color (whiteness): L, a, and b values were measured using a color difference meter (Color Quest II, Hunter Lab Co.). Each of L, a, and b represents a coordinate value indicating a unique color, and L may have a value ranging from 0 to 100. The closer to 0, the blacker, and the closer to 100, the whiteer. a can have positive and negative numbers based on 0, a larger value of 0 means a red color, and a value smaller than 0 means a green color. b can have positive and negative numbers based on 0. When it is larger than 0, it means that it has a yellow color. When it is smaller than 0, it means that it has a blue color.

* Evaluation of staying (staying stability): In injection molding, ABS graft resin was retained in a high-temperature extruder at 250 ° C. for 15 minutes, and the b value was measured

* Thermal stability:

1) O.I.T: Oxidative Induction Time (OIT) was measured using Differential Scanning Calorimetry (DSC). OIT refers to the time it takes for oxidation to occur while oxygen is added under isothermal conditions. The larger the OIT, the better the thermal stability. In the present invention, measurement was carried out while introducing 50 ml / min of oxygen under the condition of 190 占 폚.

2) Scorch test: The sample was placed in an oven at 190 ° C, and the time until vaporized gas was generated when the sample ran to detect the carbide vaporized in the sensor was analyzed by a measurement method.

division color Thermal stability L a b O.I.T Scorch TEST
(190 DEG C) 210 ℃
(Processing temperature) 250 ℃
(Processing temperature) 250 ℃
(Processing temperature + stay evaluation) Comparative Example 1 powder - - - - - 4.46 60 minutes Psalter 86.98 -2.66 10.68 12.29 13.9 - 120 minutes Comparative Example 2 powder - - - - 5.74 10 minutes Psalter 86.49 -2.29 11.18 13.67 15.46 60 minutes Example 1 powder - - - - - 13.46 90 minutes Psalter 87.87 -2.28 9.09 10.66 13.09 - 160 minutes

As shown in Table 1, it was confirmed that the ABS graft resin of the present invention (Example 1) containing sulfuric acid and magnesium stearate was excellent in retention stability, color and thermal stability, but magnesium sulfate was used as a coagulant (Comparative Example 1) and ABS grafted resin (Comparative Example 2) in which sulfuric acid was used as a flocculant but magnesium stearate was not added during processing were compared with the ABS graft resins of the present invention, Is small and b value is large, color stability and stability are poor, OIT value is small and Scorch characteristic is poor.

Since the magnesium sulfate used in the agglomeration remains in the powder, it is coupled with oxygen in the air of the metal ion and rapidly oxidized to provide a cause of discoloring the color of the powder and the color of the resin. However, when an acid flocculant is used, there is almost no residual metal ion due to neutralization of the end of the emulsifier as described above, and the emulsifier present in acid form acts as a lubricant. In the injection process, Thereby reducing the amount of resin that receives locally high heat, thereby minimizing the color change. In order to assist in the kneading of the resin during the pressure and injection, a small amount of solid magnesium stearate was injected before the injection molding to improve the processing characteristics of the resin, thereby improving the thermal stability. As a result, it was confirmed that the color change was the smallest even after the injection stay and the scorch test result of the pellet was the best after extrusion. In addition, it was possible to produce a product having excellent thermal stability of the powder.

Claims (14)

Inorganic acid and metal stearate salts,
Wherein an aromatic vinyl monomer and a vinyl cyan monomer are graft polymerized in a rubber latex having an average particle diameter of 0.08 to 0.16 占 퐉 and a rubber latex having an average particle diameter of 0.26 to 0.34 占 퐉. The method according to claim 1,
Wherein the inorganic acid is sulfuric acid or hydrochloric acid. The method according to claim 1,
Wherein the inorganic acid is contained in an amount of 0.5 to 3.0 wt%. The method according to claim 1,
Wherein the metal stearate salt is magnesium stearate, calcium stearate or a mixture thereof. The method according to claim 1,
Wherein the metal stearate salt is contained in an amount of 0.8 to 3.0 wt%. The method according to claim 1,
Wherein the ABS graft resin further comprises 0.5 to 5% by weight of a carboxylic acid. The method according to claim 1,
Wherein the ABS grafted resin is produced by emulsion polymerization. A process for preparing an ABS grafted resin comprising an emulsion graft polymerization step, an aggregation step of a polymer latex, and a processing step,
Wherein the emulsion graft polymerization is carried out by graft-polymerizing an aromatic vinyl monomer and a vinyl cyan monomer onto a rubber latex having an average particle diameter of 0.08 to 0.16 탆 and a rubber latex having an average particle diameter of 0.26 to 0.34 탆, And the processing step is carried out by introducing a metal stearate salt into the ABS graft resin. 9. The method of claim 8,
Wherein the inorganic acid flocculant is sulfuric acid or hydrochloric acid. 9. The method of claim 8,
Wherein the inorganic acid flocculant is added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the total polymer latex. 9. The method of claim 8,
Wherein the metal stearate salt is magnesium stearate, calcium stearate or a mixture thereof. 9. The method of claim 8,
Wherein the metal stearate salt is added in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the total amount of the ABS resin powder. 9. The method of claim 8,
Wherein the emulsion graft polymerization is carried out by using a carboxylate emulsifier as an emulsifier. 9. The method of claim 8,
Wherein the processing step comprises an extrusion step and an injection step.