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
1996-11-08
1998-11-24
Hoke, Veronica P.
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...
423274, 4234202, 423463, 423600, 524424, 524434, 524436, C01F 716, C08K 310
Patent
active
058407928
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel complex metal hydroxide salt wherein metal consists of lithium, magnesium and/or zinc, and aluminum, a stabilizer for halogen-containing resin which comprises said complex metal hydroxide salt, a process for preparing the stabilizer and a halogen-containing resin composition which comprises said resin stabilizer.
BACKGROUND ART
It is well known that when halogen-containing resins such as a polyvinyl chloride resin and the like are subjected to a heat molding process, there occur troubles such as coloration and deterioration of the resins as well as corrosion formation in a molding machine by hydrochloric acid deriving from a heat decomposition reaction of dehydrochlorination. The heat decomposition of polyvinyl chloride resin is generally considered to be promoted by catalytic action of hydrogen chloride which generates in an early stage of decomposition. Therefore, it has been widely conducted to incorporate stabilizers for neutralizing and capturing hydrogen chloride in the early stage of decomposition.
As such a stabilizer, hydrotalcite represented by the formula Mg.sub.(1-x) Al.sub.x (OH).sub.2 A.sup.-n.sub.x
.mH.sub.2 O is known, and the use of the hydrotalcite is disclosed in Japanese Patent Unexamined Publication Nos. 80445/1980, 36012/1983 and 30737/1984.
Hydrotalcite where Al(OH).sub.3 forms a solid solution in Mg(OH).sub.2 consists of positively charged basic layers and interlayer consisting of an anion for neutralizing the positive charge and water of crystallization, and therefore it has some extent of thermal stability. The stabilizing action by the hydrotalcite is based on the neutralization and exchange of halogen with an anion, especially carbonate ion. However, the hydrotalcite has some defects. The anion content in the hydrotalcite is not sufficient to ensure high stability and it impairs transparency when incorporated into resin in large amount. For these reasons, compounds having more excellent stabilizing action have been required.
Japanese Patent Unexamined Publication No. 179052/1993 proposes a resin stabilizer comprising lithium aluminum complex hydroxide salt for solving the problem of the above-mentioned hydrotalcite.
Though the above-mentioned lithium aluminum complex hydroxide salt exhibits some extent of thermally stabilizing action for a halogen-containing polymer like the hydrotalcite, there is a problem that it makes the resin colored strongly owing to high content of an alkali metal (lithium) of an electron donor nature. Therefore, it can not be put into practical use.
DISCLOSURE OF THE INVENTION
As a result of having ardently studied for solving the above problem, the present inventors have succeeded in development of a stabilizer for a halogen-containing resin in which the alkali metal content is low and which causes almost no coloration by substituting a part of lithium ion to enter a vacant site of an aluminum hydroxide octahedron layer of the gibbsite structure for the divalent metals of Mg and/or Zn. Also, this resin stabilizer wherein a part of lithium ion is substituted for the divalent metal induces increase in the quantity of an anion to supply electron charge so that an ion exchange capacity with halogen become large thereby the thermally stabilizing action is markedly improved in comparison with the hydrotalcite and lithium aluminum complex hydroxide salt. In this case, the complex hydroxide salt where Zn ion is intercalated between the layers exhibits improved thermal stability effect in initial coloration.
According to the present invention, there is provided a stabilizer for a halogen-containing resin which is characterized by containing a complex (Li.sub.(1-x).M.sub.x)(OH).sub.6 !.sub.n (A.sup.-n).sub.1+x.mH.sub.2 O . . . Formula I wherein A is an inorganic or organic anion, M is Mg and/or Zn, n is a valence number of anion A, m is 0 or positive number, and x satisfies the expression 0.01.ltoreq.x<1.
Thus, the complex hydroxide salt for use in the present invention is one wherein anion was i
REFERENCES:
patent: 5232627 (1993-08-01), Burba et al.
Machimura Hitoshi
Murakami Tatsuo
Taniguchi Akiko
Fuji Chemical Industry Co., Ltd.
Hoke Veronica P.
Novick Harold L.
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