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
1998-07-21
2001-03-06
Lipman, Bernard (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...
C525S331600, C525S358000
Reexamination Certificate
active
06197895
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a production method of chlorinated polyvinyl chloride resin. More precisely, it relates to a production method of a chlorinated polyvinyl chloride resin which makes it possible to shorten the time for chlorination reaction without sacrificing the initial coloring and heat stability of the chlorinated polyvinyl chloride resin, thereby improving productivity thereof.
2. Prior Art
A chlorinated polyvinyl chloride resin (hereinafter, referred to as “CPVC”) can be obtained by chlorination of a polyvinyl chloride resin (hereinafter, referred to as “PVC”). CPVC is characterized by having a heat resistance superior to that of PVC while keeping excellent properties of PVC, and therefore it is used for pipes, joints, industrial plates, sheet or the like wherein heat resistance is required.
However, CPVC is not good in heat stability compared with PVC, that is, it is easily decomposed by heat during a molding process, which makes a long duration molding process problematical or discoloration may occur particularly in a transparent molded product, or some other problems may occur.
Production methods of CPVC, wherein chlorine gas is blown into a aqueous suspension of PVC under beaming of a mercury lamp, have been disclosed in Japanese Laid-Open Patent Publications Sho 58-103507 (1983) and Sho 64-6002 (1989), for example. In these publications, it has been proposed to shorten the time for chlorination and thereby to improve the productivity. That is, it is described that the time for chlorination is shortened and consequently the productivity is improved mainly by increasing the intensity of the mercury lamp together with raising the temperature of reaction in a process of chlorination reaction.
However, in obtaining CPVC by these methods, because of the above-mentioned problems inherent in CPVC, that are the initial coloring problem in the molding process and the deterioration of heat stability, shortening the time for reaction significantly has not yet been achieved.
In other words, as a production method of CPVC, a method to shorten the chlorination reaction time and thereby to improve the productivity without sacrificing the initial coloring and the heat stability has not been proposed yet, as a matter of fact.
PURPOSE OF THE INVENTION
The purpose of the present invention is to provide a production method of chlorinated polyvinyl chloride resin which is characterized by that the time for chlorination reaction can be shortened without sacrificing the initial coloring and the heat stability during molding process, whereby the productivity is significantly improved.
SUMMARY OF THE INVENTION
As a result of intensive study by the inventors of the present invention to solve the above-mentioned problems, it was found that in the chlorination process of PVC in the state of aqueous suspension under beaming, it is possible to shorten the time for chlorination reaction without sacrificing the initial coloring and the heat stability and thereby to improve the productivity significantly, by adding a certain amount of a specific kind of organic peroxide into the reaction vessel, and the present invention has been achieved.
That is, the method for production of CPVC of the present invention is characterized by that an organic peroxide compound having a 10 hour half-life in the range from 40 to 90° C. is added into the reaction vessel in a ratio of 0.01-1 part to 100 parts of the PVC by weight before the chlorination reaction is started, when a method for production of CPVC is performed, which method comprises a step of suspending PVC in an aqueous medium, and a step of blowing chlorine gas into said suspension under the beam of a mercury lamp within the temperature range of 40-90° C., thereby producing CPVC having a chlorination degree ranging from 60 to 73% by weight.
According to the present invention, a method for production of CPVC is provided wherein the time for chlorination reaction is shortened without sacrificing the initial coloring and the heat stability, whereby the productivity is significantly improved.
DETAILED DESCRIPTION OF THE INVENTION
PVC employed in the present invention is a polymer of vinyl chloride type monomer. In the vinyl chloride type monomer, vinyl chloride monomer and other monomers to be copolymerizable with the vinyl chloride monomer are involved. As examples of the monomers copolymerizable with a vinyl chloride monomer, mentioned are ethylene, propylene, vinylacetate, aryl chloride, aryl glycidyl ether, acrylic acid ester, methacrylic acid ester, vinyl ether and so on, and these monomers are used alone or as a combination of two or more kinds of monomers. And the amount of these monomers to be employed is approximately 0-20 parts to 100 parts of vinyl chloride monomer by weight.
The production method of PVC employed as a raw material is not particularly limited. That means, PVC to be employed can be prepared by any method such as suspension polymerization, emulsion polymerization, solution polymerization of bulk polymerization. The suspending agent employed in the suspension polymerization is not limited.
Average polymerization degree of PVC is not particularly limited either, but from the point of view that the application of the obtained CPVC is pipe, joint, industrial plate, sheet or the like, it is preferably in the range of 400-2,000. When the average polymerization degree is lower than 400, the impact strength of the molded products tend to be deteriorated, and when it is over 2,000, the melt viscosity of CPVC tends to be high which makes processing hard.
The organic peroxide compound having a 10 hour half-life in the range of 40-90° C. (an organic peroxide compound which requires 10 hours to decompose until becoming a half at some temperature in the range from 40° C. to 90° C.) employable in the present invention is a known chemical compound, which is a diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal or the like. As concrete examples, mentioned are di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, di-2-ethoxyethylperoxydicarbonate, di(2-ethylhexylperoxy) dicarbonate, t-hexylperoxyneodecanoate, dimethoxybutylperoxydicarbonate, di(3-methyl-3-methoxybutylperoxy)dicarbonate, t-butylperoxyneodecanoate, 2,4-dichlorobenzoyl peroxide, t-hexylperoxypivalate, t-butylperoxypivalate, 3,5,5-trimethylhexanoyl peroxide octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic acid peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxide)hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, m-toluoyl-and-benzoyl peroxide, t-butylperoxyisobutylate, 1,1-bis(t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane or the like. In the present invention, such organic peroxide compound is used alone or as a combination of two or more kind of the compounds.
When an organic peroxide compound having the half-life period of 10 hours at a temperature out of the range of 40-90° C. is employed, the effect of shortening the time for chlorination reaction is not obtained. An organic peroxide compound which is soluble in an organic solvent is preferred to a water-soluble one in effectiveness of shortening the time for chlorination reaction.
The temperature at which the half-life period is 10 hours is more preferably in the range of 45-80° C., and by using the organic peroxide compound having the half-life period of 10 hours at any temperature in this range, the effect of shortening the time for chlorination reaction can be seen more significantly.
The above-mentioned organic peroxide compound is to be added into the reaction vessel in the ratio of 0.01-1 part to 100 parts of PVC by weight before the chlorination reaction is started. In case that the ratio of the co
Isshiki Minoru
Shiota Hiroaki
Suzuki Takeyuki
Jordan and Hamburg LLP
Kaneka Corporation
Lipman Bernard
LandOfFree
Process for production of chlorinated polyvinyl chloride resin does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for production of chlorinated polyvinyl chloride resin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for production of chlorinated polyvinyl chloride resin will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2500663