Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1993-08-06
1994-10-18
Langel, Wayne
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
423306, C01B 2545, C08K 332
Patent
active
053569822
DESCRIPTION:
BRIEF SUMMARY
The invention relates to basic calcium aluminum hydroxy phosphites, a process for their production and their use as stabilizers for halogen-containing polymers, in particular polyvinyl chloride.
Halogen-containing thermoplastic resin compositions or shaped articles produced therefrom are decomposed by the influence of heat or light. For this reason, stabilizers must be added to these resins. For especially demanding articles such as profiles, plates or pipes inorganic and/or organic compounds of toxic heavy metals such as lead, barium or cadmium are used. 2-basic lead phosphite achieved a special importance in the stabilization of e.g. rigid PVC articles where good thermal and good light and weather resistance are required. The use of basic lead phosphite as a stabilizer against the decomposition of PVC by heat, daylight and UV radiation is e.g. described in DD-PS 61 095. CH-PS 8 510 622 describes the stabilization of highly filled rigid and plasticized PVC products with a mixture of basic lead sulphate and lead phosphite. Another use of basic lead phosphite for PVC high-resistance foam mixtures is described in U.S. Pat. No. 4,797,426.
Since basic lead phosphite, like other heavy-metal-containing stabilizers, is classified as toxic, it has been attempted to find stabilizing alternatives. A great number of combinations of inorganic and organic compounds are known as stabilizers for halogen-containing thermoplastic resins. In JP-PS 1 213 865 and JP-OS 80 445/80 a hydrotalcite is suggested as a stabilizer. This substance is superior to mixtures of Ca/Zn metal soaps as regards heat stability and transparency. However, the problem of the discolouring of the resin during processing cannot be solved by the use of hydrotalcite. It is suggested according to JP-OS 80 444/82 to use combinations of hydrotalcite and 1,3-diketone compounds to overcome this problem. Moreover, hydrotalcites have the disadvantage that they split off water and carbon dioxide at the processing temperatures customary for PVC. It is suggested in EP-A- 0 256 872 to eliminate this disadvantage by adding very finely divided magnesium oxide.
DE-A- 39 41 902 (prior art within the purview of Section 3 II of the German Patent Act) describes basic calcium aluminum hydroxy phosphites of the formula halogen-containing polymers.
The invention is based on the object of providing new compounds and a process for their production, which are in particular suited as stabilizers for halogen-containing polymers without having the aforementioned disadvantages of the known stabilizers, and are in particular classified as non-toxic.
This object is attained according to the invention by the making available of basic calcium aluminum hydroxy phosphites of the general formula ##EQU2## and m=0-12, with the proviso that y.noteq.1, if x=2-8.
x means preferably 2 to 8, especially preferred 3-6, and m means preferably 2-4 in the aforementioned formula.
Examinations by means of x-ray diffraction have shown that the compounds according to the invention do not belong to the hydrotalcite type as regards their crystal structure.
It became surprisingly apparent that the calcium aluminum hydroxy phosphites according to the invention impart halogen-containing thermoplastic resins and the shaped articles produced from them heat stabilities comparable to those imparted by basic lead phosphites. The compounds according to the invention prevent discolourings in the production of e.g. rigid shaped PVC articles, colour retention, and weather stability of the shaped articles stabilized with the compounds according to the invention are also equivalent to those of products stabilized with toxic heavy metal compounds.
The subject matter of the invention is also a process for the production of the calcium aluminum hydroxy phosphites according to the invention, which is characterized in that mixtures of calcium hydroxide and/or oxide, aluminum hydroxide and sodium hydroxide or of calcium hydroxide and/or oxide and sodium aluminate is reacted with phosphorous acid in amounts corresponding to t
REFERENCES:
patent: 4883533 (1989-11-01), Kosin et al.
patent: 5298545 (1994-03-01), Razvan et al.
Beck Reinhard
Kurzinger Alfred
Purzer Albert W.
Razvan Coriolan
Rosenthal Michael
Barlocher GmbH
Langel Wayne
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