Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1981-07-01
1983-03-29
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525 53, C08F27902
Patent
active
043784526
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention concerns a method of manufacturing rubber modified styrene resins having an excellent impact resistance. More particularly, the present invention concerns a method of continuously manufacturing rubber modified styrene resins with a remarkably improved impact resistance at the portions where polystyrene molecule orientation tends to occur in the molded product.
Background of Art
In the conventional art, rubber modified styrene resins are manufactured by the continuous bulk polymerization or solution polymerization or by the batch type bulk-suspension polymerization method. There have been proposed various methods for continuously manufacturing rubber modified styrene resin in the art. One of the methods which uses organic peroxide is disclosed in Japanese Patent Publication No. 37233/1976. As the uses for rubber modified styrene resins are becoming more and more diversified and multiplied today, and the said resins are used as a material for complicatedly shaped molded products, an extremely important problem facing the industry concerned is to secure the impact strength at the portions where polystyrene molecule orientation tends to occur within the molded product.
In other words, the rubber modified styrene resins obtained by the conventional manufacturing method have the problem in that when molded into a complex shape certain portions tend to become destroyed by the impact caused by the crash of an object during actual use. When such a phenomenon of the destruction was studied, it was found that the portion in question coincided with the portion where orientation of the polystyrene molecules tended to occur, and judging from the results by the evaluation of falling weight impact test, the impact strength where polystyrene molecule orientation tended to occur in the molded product decreased inordinately.
Generally such a degree of orientation in the styrene resin molded product depends on the molding conditions, but it may also be improved by the manufacturing method of the resin itself.
The object of the present invention is to provide a method for manufacturing rubber modified styrene resin with an improved impact strength at the portions where polystyrene molecule orientation tends to occur in the molded product.
DISCLOSURE OF THE INVENTION
"The portions where polystyrene molecule orientation tends to occur in the molded product" as mentioned in the following discussion of the present invention coincide with the portions where excessive thermal contraction occurs at the time of heating (80.degree.-120.degree. C.) when the product is molded with polystyrene resins. The absolute amount of thermal contraction depends on the molding conditions, but it was found that the impact strength at the portions with a relatively larger degree of thermal contraction was uniquely lower in the molded product with a complex shape.
Surprisingly, if the resin was manufactured by the continuous polymerization method where organic peroxide, initiator for radical polymerization, was supplied under specifically restricted conditions, the impact strength was observed to improve greatly at the portions where polystyrene molecule orientation tended to occur in the molded product. The present invention was completed based on this finding.
According to the present invention, there is provided a method of manufacturing rubber modified polystyrene resins:
In a method of manufacturing rubber modified styrene resins from a styrene monomer and a butadiene polymer by bulk polymerization or solution polymerization method using an organic peroxide as an initiator, the improvement which comprises
(A) the 1st step of polymerizing the styrene monomer in the presence of butadiene polymer and the organic peroxide at the ratio of 100 parts by weight, 3-15 parts by weight and 0-0.01 parts by weight respectively until the polymerization yield of the styrene monomer becomes 2 to 5 times more than the weight of the butadiene polymer; and
(B) the 2nd step of polymerizing the full amount of polymerization
REFERENCES:
patent: 3903202 (1975-09-01), Carter
patent: 3945976 (1976-03-01), McCurdy
patent: 4012462 (1977-03-01), Chaudhary
patent: 4187261 (1980-02-01), Slama
patent: 4254236 (1981-03-01), Burk
patent: 4255315 (1981-03-01), Anspon
patent: 4282334 (1981-08-01), Walter
Ishida Yuzuru
Ito Norifumi
Iwamoto Mune
Matsubara Tetsuyuki
Michl Paul R.
Mitsui Toatsu Chemicals Inc.
LandOfFree
Method of manufacturing rubber modified styrene resins does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing rubber modified styrene resins, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing rubber modified styrene resins will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1204585