Note: Descriptions are shown in the official language in which they were submitted.
~59~7~
FLOWER PRESERVATION
This application relates generally to the preservation
of flowers and more particularly to a process and novel compos-
ition of matter for the preservation of the natural colours of
flowers, and to the preserved flower product.
The preservation of flowers for museum specimens, for
educational purposes in the natural sciences and elsewhere, for
decorative and ornamental use, for displays and the like has
been practised for many years and many processes for such pre-
servation have been described in the literature. ~ttention is
particularly directed to U.S. Patents 2l65~,929; 2,658,836 and
3,698,809 to Fessenden and U.S. Patent 2,971,292 to Malecki
and to "Handbook of Plastic Embedding" E. L. Lutz (1969) P. 60-
73 for descriptions of the processes employed heretofore for
the preservation of flowers and other plant and animal tissues.
Such prior art processes are not, however, entirely satisfactory
because the delicate natural colours of the flowers tend -to fade
relatively quickly and the flowers are also extremely brittle,
fragile and highly susceptible to damage in extremes of temper-
ature or humidity so that special handling and storage
techniques are necessary. Without such special techniques the
natural beauty oE the flowers is ~uickly lost and the flowers
lose their usefulness for display or educational purposes.
Indeed, storage in sealed bells or embedding in plastic have
heretofore been the onLy practical methods oi storage and handl~
~591~1
ing. Further, in order to trea-t d:ifferently coloured flowers
according to the prior art it has been found necessary to use
a variety of treatment solu-tions as no single treatment solu-
tion which is suitable for all colours of flowers, has evolved.
It is, therefore, an object of the present invention to
provide a process and a single composition of matter for the
preservation of flowers which is suitable for use with substant-
ially all colours and varieties of flowers and which will result
in naturally coloured flowers which retain the freshness, flex-
ibility and beauty for relatively long periods of time wi-thout
the necessity of special handling and storage techniques.
-In our earlier Canadi`an Patent 1,091,950 issued
Decen~er 23, 1980 and assigned to the assignee of the
present application, we have disclosed essentially
water free composi.~ions, for the single step preserva-tion of
fresh, naturally coloured blooms, comprising at least one de-
hydrating alcohol, a urea-containing compound, a carboxylic
acid, an alkaline citrate, an affective amount of at least one
of: aluminum or magnesium sulphate, a transitional metal
sulphate and an alkaline formaldehyde sulfoxylate, and zero to
an effective amount of at least one of a silicone fluid and a
silicone resin and which also contains a sufficient quantity of
at least one compound of the group consisting of an alkaline
phosphate, a lower carboxyli.c acid and phenol so as to ensure
that the composition has a pH in the range 5 to 7.
A preferred composition within the a~ove general
formula comprises, in amounts per litre:
175-575 ml.. tertiary butyl alcohol
100-300 m:l.. l-propanol
200-400 nll.. 2-propan Q 1
~ ~;927~L
6-8 g. sodium phosphate
0-3 g. sodium formaldehyde sulfoxylate
2.5-7.5 g. ci-tric acid
10-20 g. thiourea
0-10 g. aluminum sulpha-te
3-12 g. sodium citrate
0-2 g. cupric sulphate
10-200 ml. silicone fluid
0-50 ml. silicone resin, and
0-62 ml. phenol (88%).
Such formulations are effective for substantially all coloured
blooms but have the disadvantage that they are relatively cost-
ly to prepare. We have now found that surprising good results
may be obtained using generally similar solutions which are
very much cheaper to prepare.
By one aspect of the present invention there is provided
a composition for the single step preservation of fresh, natural-
ly coloured blooms comprising (in amounts per litre of solution):
600-700 ml. tertiary butyl alcohol
200-250 ml. 2-propanol
.~ ~
3-30 g. thiourea
3-30 g. citric acid
3-30 g. sodium citrate
50-15Q ml. proprionic acid
0-250 ml. phenol.
By a preferred aspect of the present inventlon there is
provided a composition for the single step preservation Gf fresh
naturally coloured blooms, comprising (in amounts per litre):
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~59127~L
675 ml. tert-butyl alcohol
225 ml. 2-propanol
g. thiourea
g. citric acid
g. sodium citrate
100 ml. propionic acid.
Tertiary butyl alcohol is an extremely efficient de-
hydrating agent and if used alone tends to produce brittle blooms.
The effects of the tertiary butyl alcohol are modified to some
extent by inclusion of 2-propanol which also lowers the freezing
point of the tert-butyl alcohol.
A urea-containing compound, preferably thiourea~ is an
essential constituent to prevent loss of pigments from the blooms
and, when used together with citric acid and sodium citrate which
are also colour preservatives, it increases the efficiency of
these chemicals and prolongs the act.ive life of the composition.
Although effective at relativel~ low concentrations the life of the
composition is severely restricted for reasons described in more
detail in our copending application referred to above. A higher
concentration of thiourea is generally used in the present formul-
ations than in the formulations of the copending application to
compensate for the omission of many of the other, more expensive,
constituents used therein.
Propionic acid and phenol are employed as pH buffers, de-
hydrating agents and colour stabilizers. A relatively large pro-
portion of propionic acid is particularly effective to control
the darker reds and pinks and phenol is particularly effective
to control the lighter reds. A mixture of phenol and propionic
acid tends to make the reds more vivid~
The process to treat the iJlooms according to the pre-
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~ ~ S~ 27~
sen-t invention is quite simple and straightforward. ~ fresh
bloom is chosen and a floral wire is inserted into the stem or
bloom and a weight is added to keep the bloom submerged in the
composition. The composition, formulated as described herein-
above is contained in a suitable bath or container at a tempera-
ture in the range of about 45-75F. The bloom is left suspended
in the bath for from 6 to 24 hours without any agitation, depend-
ing upon size and water content of the bloom and the freshness of
the solution. Upon immersion in the composition, substantially
all colour appears to disappear from the petals as dehydration
occurs under the action of the clehydrating alcohols. rrhe colour
slowly returns to the normal pretreatment level as the solid
colour fixers and the like take up the extracted water and active-
ly enter solution, thus ~iving a useful indication of the treat-
ment time required. Large, fleshy blooms require longer periods
of immersion and care must be taken to ensure the bloom is
immersed sufficiently long to treat the relatively heavy and
impervious torus. Fpllowing the immersion treatment the bloom is
removed from the composition and air dried at room temperature
~0 and relatively low humidity for 8 to 10 hours. Blooms thus treated
can generally be stored and displayed without further treatment
for relatively long periods of time (of the order of 4-6 months
at least) provided the temperature and humidity conditions are
suitable (i.e. up tv about 80F and 60-70~ relative humidity.
More stressful environmental conditions require that the bloo~ms be
stored in sealed ylass domes, where they will likely las-t fci~ x~e;, ;^s
or be further cocltea. I-t has been found that dipping or sprayin~
with a conformal (oating resin, such as Dow Corning R~3117 ~iilicc>ne
Resin alone or diluted with Dow Corning Fluid 200 (Registered
,.~
.
Trademark) (at 0.65 centistokes) or any o-ther diluent, is
satisfactory for this purpose. Preferably the coating is
applied by dipping the bloom into the resin thinned wi-th a
diluent such as xylene at a temperature in the range 50-80F
for a few minutes. ~he coated bloom is then dried at room
temperature for several hours to cure the resin coating. The
resin cures to a clear shiny coating and leaves the bloom
relatively pliable. The shiny surface is often desirable but
if a matte surface is desired this can be sprayed on with any
one of a number of known finishes. The thickness of the coat-
ing has a bearing on the appearance of the bloom --thin
coatings lend a natural and delicate appearance to the bloom,
while thick coatings make for sturdy blooms often of special
beauty. After a coating treatment as described herein, roses
and geraniums for example, have been exposed to light equal to
several million foot-candle-hours, 95% humidity and tempera-
tures up to 85F with only slight colour fading. Under more
normal conditions the colours remain unaltered.
Example 1
Samples of roses and orchids as detailed
below were preserved in a solution comprising:
675 ml. tert-butyl alcohol
225 ml. 2-propanol
25 g, thiourea
25 g. citric acid
25 g. sodium citrate
100 ml. propionic acid.
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The stems of individual blooms were wired and the blooms
suspended in the preserving compositions a-t room temperature
(45-70F~ for periods ranging from 6-24 hours depending on the
size and water con-tent oi the bloom and the freshness of the
preserving composition. In some cases i-t was necessary to
attach a weight to the wire to ensure total imrnersion o~ the
bloom in the composition. After the immersion treatment the
blooms were removed from the composition and air dried at
relatively low humidity (preferably less than 50%) for 8 to
10 hours. If higher humidities are encountered it may be
necessary to take special steps to avoid reabsorption of water,
such as be immersion in a resin such as Dow Corning R43117
with a solvent such as xylene. In some instances the dried
blooms were subsequently coated with a coating or spray of a
silicone resin at 50-80F. The quality of the preserved blooms
was then evaluated.
_oses Orchids_ __
Li~ht Red - yood Blue - good
Dark Red - good Yellow - good
White - good White ~ good
Example 2
Sam~les o~ roses and orchids as in Example 1 were
preserved in a solution comprising: ~
600 ml. -tert-butyl alcohol
200 ml. 2-propa~ol
100 ml. vhenol
100 ml. propionic acid
g. citric acid
g. sodium citrate
g. thiourea
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~L~L59Z71
according to the method of Example 1. The results were as
follows:
Roses Orchids
Light Red - goodBlue - good
Dark Red - goodYellow - good
White - good White - good.
, - 8 -
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