Candle wax stabilized with imidazolidines

Details Candle wax stabilized with imidazolidines Candle wax stabilized with imidazolidines

2001-04-02

2003-04-15

Medley, Margaret (Department: 1714)

Fuel and related compositions

Candle composition

C431S288000

Reexamination Certificate

active

06547840

ABSTRACT:

The instant invention pertains to white, dyed, dipped, unscented and/or scented candle wax which is effectively stabilized against discoloration and fading by the incorporation therein of an imidazolidine in combination with a UV absorber and/or an antioxidant.
BACKGROUND OF THE INVENTION
Candles have been known for many centuries going back to the eighth century B.C. The nature of candles is described in Ullmann's Encyclopedia of Industrial Chemistry, Volume A5 at pages 29-30 where it is seen that candles are made from paraffin, beeswax and stearin as basic materials, and where a host of additives may also be present.
It is not surprising that with candles and wax becoming increasingly more important attention was paid as to how to stabilize the said materials. At the National Candle Association Meeting in Houston, 1994, R. van der Vennet presented a paper on “Antioxidants in Wax—Replacement of BHT” touting the use of Vitamin E (tocopherol) as an antioxidant to prevent the yellowing of wax when oxidized. WO 94/13736 describes the same invention.
EP 359,488 A3 and EP 133,964 B1 describe stabilized waxes used in cosmetics where the waxes are the same or similar to those used in candles.
EP 5,922 A1 describes lip cosmetics where the waxes are useful in lipsticks and are related to those useful in candles.
U.S. Pat. No. 5,879,694 describes in detail transparent gel candles both in composition and structure. The use of BHT as an antioxidant is mentioned.
At the National Candle Association Technical Meeting on Apr. 16, 1998, F. A. Ballentine et al., presented a paper entitled “Inhibiting Color Fading of Dyed Candles with CYASORB® Light Absorbers” in which the general theories of thermal oxidation and photodegradation are discussed along with data on the effect of light absorbers on color stability of dyed candle waxes. The light absorbers compared are 4-octyloxy-2-hydroxy-benzophenone UV-531; 4-methoxy-2-hydroxybenzophenone UV-9; 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole UV-5365; 2-(2-hydroxy-5-tert-octylphenyl-2H-benzotriazole UV-5411 and 2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole UV-2337).
U.S. Pat. No. 5,964,905 teaches dyed and scented candle gels containing triblock copolymers and a hydrocarbon oil of high flash point. This reference teaches that a light (UV) absorber may be used to improve the shelf stability of the candle color when exposed to visible or ultraviolet light. Two preferred absorbers are ethylhexyl p-methoxycinnamate (PARSOL® MCX, Roche) and 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole (CYASORB® 5411, Cytec).
Imidazolidines have been known as stabilizers for various substrates. British Patent No. 1,145,470 teaches the stabilization of polyolefins using alkylated 4-oxoimidazolidine-1-oxides such as 2,2,5,5-tetramethyl-4-oxoimidazolidine-1-oxide.
U.S. Pat. No. 4,448,969 discloses the use of cyclic ether or carbonate alkylation products of 2,2,5,5-tetramethylimidazolidin-4-one for the stabilization of synthetic polymers, particularly polyolefins.
U.S. Pat. Nos. 4,804,717 and 4,895,901 teach that polymeric hindered amine light stabilizers are useful for the stabilization of olefin, styrene and acrylate polymers which contain a minor amount of a pendant moiety derived from 3-hydroxy-2,2,5,5-tetramethylimidazolidine-4-one.
European Patent Specification 313,941 B1 describes the stabilization of photochromic dye compositions using 1-oxyl-2,2,5,5-tetramethylimidazolidin-4-one.
WO 00/22037 teaches the stabilization of solid, shaped and colored wax articles, including candles, using a malonate UV absorber which may optionally contain a hindered amine moiety as part of the malonate compound structure. The wax articles are dyed with a variety of oil soluble dyes and pigments. The samples protected by dimethyl p-methoxy-benzylidinemalonate exhibited better resistance to discoloration that did samples stabilized with selected benzotriazole or benzophenone UV absorbers.
Japanese Hei 3-278554 teaches that wax crayons (drawing materials) colored by organic pigments can be stabilized by a hindered amine and/or benzotriazole.
U.S. Pat. No. 6,020,491 teaches the use of monomeric and polymeric cyclic amine and N-halamine compounds as biocides and disinfectants for a host of substrates. Some of the structures include a substituted 2,2,5,5-tetramethylimidazolidine moiety in a pendant group.
WO 98/30601 describes a method of controlling polymer molecular weight and polymer structure by living free radical polymerization where nitroxide and alkoxyamine containing a 2,2,5,5-tetramethylimidazolidine moiety are employed.
WO 99/61396 teaches the method of stabilizing unsaturated organic polymers using a host of polymerization inhibitors based on the alkylated 2,2,5,5-tetramethyl-imidazolidine compounds.
In respect to wax stabilization, the use of selected hindered amines and/or benzotriazole UV absorbers is also known in the prior art as seen in U.S. Pat. Nos. 3,530,084; 4,379,721; 4,616,051 and 5,964,905 and in copending applications Ser. Nos. 09/495,495, 09/495,496 and 09/741,583.
None of these references teach the superior performance provided when the imidazolidine compounds are used in conjunction with a UV absorber and/or antioxidant to stabilize candle wax.
OBJECTS OF THE INVENTION
The object of the invention is to provide for a white and unscented; white and scented; dyed and unscented; dyed and scented; dipped and unscented; or dipped and scented candle wax stabilized by a combination of an imidazolidine compound with a UV absorber and/or antioxidant.
DETAILED DISCLOSURE
The instant invention pertains to a composition which comprises
(a) candle wax which is white and unscented; white and scented; dyed and unscented; dyed and scented; dipped and unscented; or dipped and scented, and
(b) an effective stabilizing amount of a combination of
(i) an imidazolidine compound containing a moiety of generic formula I
(ii) a UV absorber or an antioxidant, or a UV absorber and an antioxidant
wherein the ratio by weight of (i) to (ii) is from 10:1 to 1:10.
In another embodiment of the instant invention, the imidiazolidine compound of component (b)(i) is a compound of formula Ia
where
R
1
and R
2
are independently alkyl of 1 to 8 carbon atoms, or R
1
and R
2
together are tetramethylene, pentamethylene or pentamethylene substituted by methyl; and
R
3
and R
4
are independently hydrogen, oxyl, hydroxyl, aralkyl of 7 to 15 carbon atoms, alkoxy of 1 to 24 carbon atoms, alkyl of 1 to 42 carbon atoms, said alkyl substituted by one or two hydroxyl groups, said alkyl substituted by alkylcarbonyloxy of 2 to 18 carbon atoms, or said alkyl interrupted by one to twenty oxygen atoms and substituted by one hydroxyl, by alkylcarbonyloxy of 2 to 18 carbon atoms or by 4-hydroxy-3,5-di-tert-butylbenzoyloxy.
In another embodiment of the invention R
1
and R
2
are each methyl, or R
1
and R
2
together are pentamethylene.
Specific imidazolidine compounds of formula I or Ia which are useful in the instant invention include
(a) 2,2-pentamethylene-5,5-pentamethylene-imidazolidin-4-one;
(b) 2,2-pentamethylene-5,5-pentamethylene-imidazolidin-4-one-1-oxyl;
(c) 2,2,5,5-tetramethyl-4-oxoimidazoline-1-oxyl;
(d) 2,5-dimethyl-2,5-diisobutyl-4-oxoimidazoline-1-oxyl;
(e) (2,2,6,6-tetramethylpiperidine-1-oxyl)-4-spiro-2′-(4-oxoimidiazoline-1-oxyl)-5′-spiro-4-(2,2,6,6-tetramethylpiperidine-1-oxyl);
(f) 2,5-dimethyl-2,5-diethyl-4-oxoimidazoline-1-oxyl;
(g) 2,2-[(1-methyl)-1,5-pentanediyl]-5,5-[(1-methyl)-1,5-pentanediyl]-imidazo-lidin-4-one-1-oxyl;
(h) 2,2,5,5-tetramethyl-1-(2-hydroxyethyl)-imidazolin-4-one;
(i) bis-[2-(2,2,5,5-tetramethyl-4-oxo-imidazolin-1-yl)ethyl] sebacate;
(j) 2,2,5,5-tetramethyl-1-methyl-3-(2-hydroxyethyl)-imidazolin-4-one;
(k) 2,2,5,5-tetramethyl-1-methyl-3-[H(OCH
2
CH
2
)
x
]-imidazolin-4-one where x is 2 to 21;
(l) 2,2,5,5-tetramethyl-1-methyl-3-[heptadecylcarbonyl(OCH
2
CH
2
)
x
]-imidazolin-4-one where x is 2 to 21;
(m) 2,2,5,5-tetramethyl-1-methyl-3-[4-hydroxy-3,5-di-tert-butylbenzoyl-(OCH
2
CH
2
)
x
&rsq

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