Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-07-22
2004-06-22
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S258000, C525S261000, C525S262000, C525S942000, C526S911000
Reexamination Certificate
active
06753382
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on application No. 2000-66791 filed in the Korean Industrial Property Office on Nov. 10, 2000, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a method for preparing acrylonitrile-butadiene-styrene (ABS) latex, and more particularly, to a method for preparing acrylonitrile-butadiene-styrene having high total solid content through emulsion polymerization of the styrene monomer in order to graft-copolymerize the styrene monomer.
(b) Description of the Related Art
Since an acrylonitrile-butadiene-styrene (ABS) resin has excellent characteristics such as impact resistance, chemical resistance, workability, and surface gloss, it is generally used in monitor housing, computer game-player housing, home appliances, and office machines, and as the use of the ABS resin is increasing, its production also needs to be increased. However, in order to increase the production volume of the ABS resin, it does not help that new equipment for its production is added to the existing facilities. In order to solve the said problem, it has been studied that the production volume of the ABS resin increases by shortening the processing time with a shorter reaction time, an increase in the rubber content of latex, a decrease in the rubber content of the final ABS injection molding products and extrusion products, or an increase in the total solid content of latex.
In particular, though the production volume of the ABS resin is capable of increasing by increasing the total solid content of latex in a lab test, the productivity decreases on real processes, because coagulated materials generates due to the shear stress of the stirrer, and time is needed to remove the film which is formed on the latex surface during its transportation or storage.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for preparing acrylonitrile-butadiene-styrene latex having a high total solid content.
It is another object to provide a method for preparing acrylonitrile-butadiene-styrene latex having a high total solid content, which is capable of increasing in the production volume by decreasing the amount of coagulated materials which are generated during graft-copolymerization, or the film which is formed on the latex surface.
These objects may be achieved by a preparation method of the acrylonitrile-butadiene-styrene having a high total solid content, which comprises a step of emulsion polymerization of:
i) polybutadiene rubber latex;
ii) an aromatic vinyl compound; and
iii) vinyl cyanide with the addition of a reactive emulsifier thereto.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, only the preferred embodiment of the invention has been shown and described, simply by way of illustration of the best mode contemplated by the inventors of carrying out the invention. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the description is to be regarded as illustrative in nature, and not restrictive.
The acrylonitrile-butadiene-styrene latex of the present invention is prepared by the addition of an aromatic vinyl compound and a vinyl cyan compound to polybutadiene rubber latex, and emulsion copolymerization of the mixture with the addition of a reactive emulsifier, in order to decrease in the amount of coagulated materials which are generated during the emulsion copolymerization, and to prevent the film from being formed on the latex surface. Thus, the acrylonitrile-butadiene-styrene rubber latex has high productivity and total solid content of the latex.
In order to obtain the latex of the present invention, the acrylonitrile-butadiene-styrene latex is prepared by the emulsion compolymerization of:
i) 40 to 70 parts by weight of polybutadiene rubber latex;
ii) 15 to 30 parts by weight of aromatic vinyl compound; and
iii) 10 to 25 parts by weight of vinyl cyanide with the addition of 0.01 to 4.0 weight parts of reactive emulsifier thereto.
The polybutadiene rubber latex of i) is a rubber latex mixture comprising:
a) a large-diameter-polybutadiene rubber latex having a high gel content, which has a particle diameter ranging from 2600 to 5000 Å in an average diameter, the gel content ranging from 70 to 95%, and swelling index ranging from 12 to 30; and
b) a large-diameter-polybutadiene rubber latex having low gel content, which has a particle diameter ranging from 2600 to 5000 Å in an average diameter, the gel content ranging from 60 to 85%, and swelling index ranging from 18 to 40, and
more preferably, the large-diameter-polybutadiene rubber latex having high gel content of a) and large-diameter-polybutadiene rubber latex having low gel content of b) are mixed in a weight ratio of 10~50 to 50~10.
In order to perform the emulsion copolymerization efficiently, the aromatic vinyl compound and vinyl cyan compound are twice added to the mixture of rubber latex as monomers. In the first addition, 25 to 80 parts by weight of the monomers based on 100 parts by weight of the total monomers are added, and 75 to 20 parts by weight of the monomers, the remaining monomers, are added in the second addition.
That is, the acrylonitrile-butadiene-styrene latex is prepared by the steps comprising:
a) placing 40 to 70 parts by weight of the rubber latex mixture of i); 3.75 to 24 parts by weight of the aromatic vinyl compound monomer of ii); 2.5 to 20 parts by weight of the vinyl cyan compound monomer; and equal to or less than 4 parts by weight of the reactive emulsifier together in a reactor in order to react the materials first;
b) adding 6 to 26.25 parts by weight of the aromatic vinyl compound monomer of ii); 5 to 22.5 parts by weight of the vinyl cyan compound monomer of iii); and 0.01 to 4 parts by weight of the reactive emulsifier agent together or continuously to the materials of a) in order to react the mixture secondly, 30 to 90 minutes after the first reaction in the step a), and when the conversion ratio of monomers of ii) and iii) to polymers ranges from 40 to 90 wt %.
The reactive emulsifier of the present invention includes anionic emulsifiers comprising allyl, methacryloyl, and propenyl groups, or neutral emulsifier.
An exemplary anionic emulsifier agent comprising an allyl group includes sulfate of polyoxyethylene allylglycidyl nonylphenyl ether, and ADEKARIA SOAP SE based agents (a product by Asahi Denka Co.) which is suitable for a commercial market. The neutral emulsifier agent comprising an allyl group includes polyoxyethylene allylglycidyl nonylphenyl ether based emulsifiers, and ADEKARIA SOAP NE based emulsifier (a product by Asahi Denka Co.) which is suitable for a commercial market. The anionic emulsifier comprising (metha)acryloile group includes ELEMINOL RS based emulsifiers (a product by Sanyo kasei Co.), and the neutral emulsifier comprising the (metha)acryloile group includes RMA-560 based emulsifiers (a product by Nippon Surfactant Co.). An exemplary anionic emulsifier comprising the propenyl group includes polyoxyethylene nonyl propenyl ether ammonium sulfate, and AQUARON BC based emulsifiers (a product by Daiichi kogyo Seiyaku Co.) which is suitable for a commercial market. The reactive emulsifier of the present invention may be selected from the group consisting of the aforementioned agents, or may include a mixture of the aforementioned emulsifier and the non-reactive emulsifier.
Preferably, 0.01 to 4.0 parts by weight of the reactive emulsifier based on 100 parts by weights of the ABS is added to the reactive materials during emulsion copolymerization, and more preferably, equal to or less than 2 parts by weight of the reactive emulsifier is added. When equal to or more than 4.0 parts by weight of the reactive emulsifier is added, agglutination of the small-diameter-latex polymer may be bad, and when equal to or less than 2.0 parts by weight of the reactive emulsifier is added,
Chai Joo-Byung
Kim Geon-Soo
Lee Chan-Hong
Yang Byung-Tae
LG Chemical Co. Ltd.
Teskin Fred
LandOfFree
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