Note: Descriptions are shown in the official language in which they were submitted.
This appllcation relates generally to the preservation of
flowers and more particularly to a process and novel co~position 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 educa-
tional 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 preservation have been described
~,~r~ in the literature. Attention is particularly directed to U.S. Patents
J~
2,65~,929; 2,658,836 and 2,698,809 to Fessenden and U.S. Patent iL~q-r4-~
to Malecki and to "Handbook of Plastic Embedding" E.L. Lutz (1969) p.
60~73 for descriptions of the processes employed heretofore for the
preservatlon of flowers and other plant and anlmal tissues. S1~ch prior
art processes are not, however, entirely satisfactory because the
delicate natural colours of the flowers tend to fade relatively qulckly
and the flowers are also extremely brittle, fragile and highly suscepti-
ble to damage in extremes of temperature or humidity so that special
handling and storage techniques are necessary. Without such special
techniques the natural beauty of the flowers is quickly 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 of storage and handling. Further, in
order to treat differently coloured flowers according to the prior art
it has been found necessary to use a variety of treatment solutions as
no single treatment solut:Lon, 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 Eor use with substantially all colours and
varieties of flowers and which will result in naturally coloured flowers
which retain the freshness, flexibility and beauty for relatively long
periods of time without the necessity o special handling ancl storage
~l~9~9t5~
techniques.
By one aspect of this invention there is provided an essentially
~ater-free composition, for the single step preservation of fresh,
naturally coloured blooms comprising an effective amount of at least one
dehydrating alcohol, a urea-containing compound, a carboxylic acid, and an
alkaline citrate, and 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 sili-
cone resin and which also contains a sufficient quantity of at least one
compound of the group consisting of an alkaline phosphate and phenol so as
to ensure said composition has a pH in the range 5 to 7.
Thus by a preferred aspect of this invention there is provided an
essentially water-free composition for the preservation of fresh, naturally
coloured blooms, comprising in amounts per litre:
700 - 900 ml. of at least one dehydrating alcohol
6 - 8 g. alkaline phosphate
2 - 3 g. alkaline formaldehyde sulfoxylate
2.5 - 7.5 g. citric acid
10 - 20 g. thiourea
2.5 - 10 g. aluminum sulphate
3 - 12 g. alkaline citrate
.5 - 2 g. cupric sulphate
10 - 200 ml. silicone fluid
0 - 50 ml. silicone resin, and
37 - 62 ml. phenol.
By another aspect there is provided a process for preserving fresh,
naturally coloured blooms comprising immersing said blooms in an essentially
water-free composition consisting essentially of an effective amount of at
least one dehydrating alcohol, a urea-containing compound, a carboxylic acid,
and an alkaline citrate, and 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,said composition also containing a sufficient quantity of at least one
-- 2 --
.~`~ I
'~ !
~05~
compound of the group consisting of an alkaline phosphate, and phenol
so as to ensure said composition has a pH in the range 5 to 7.
By another preferred aspect of this invention there is
provided a process for preserving naturally coloured plant tissues comprising
immersing said tissues in a composition comprising
450-900 ml. of of at least one dehydrating alcohol
6-8 g. alkaline phosphate
2-3 g. alkali metal formaldehyde sulfoxylate
2~5-7.5 g. citric acid
10-20 g. thiourea
2.5-10 g. aluminum sulphate
3-12 g. alkali metal citrate
.5-2 g. cupric sulphate
10-200 ml. silicone fluld
0-50 ~1. silicone resin, and
37-62 ml. phenol,
removing said tissues from said composition and drying at substantially
room temperature.
We have found that all blooms, substantially regardless of
colour, can be successfully treated according to the invention by soaking,
as described in more detail hereinafter, in a composition comprising
(to make 1 litre):
175-575 ml. tertiary butyl alcohol
100-300 ml. l-propanol
200-400 ml. 2-propanol
6-8 g. sodium phosphate
2-3 g. sodium formaldehyde sulfoxylate
2.5-7.5 g. citric acid
10-20 g. thiorurea
2.5-10 g. aluminum sulphate
3-12 g. sodium citrate
.5-2 g. cupric sulphate
10-200 ml. silicone fluid
0-50 ml. silicone resin, and
~r,l _ 3 _
g~
37 - 62 ml. phenol (88%)
As used herein, the term "bloom" excludes the green parts thereof. Vari-
ations of constituents within the above ranges are possible and even
desirable for treatment of partlcularly coloured blooms as will be dis-
cussed in more detail hereinafter. A "universal"composition, however,
which has been found effective for virtually all colours and blooms and
which is clearly advantageous as it simplifiesinventory and stock control
and is particularly suitable for sale as a consumer-product, comprises
(per litre):
375 ml. tertiary butyl alcohol
200 ml. l-propanol
300 ml. 2-propanol
12 g. sodium phosphate
2 g. sodium formaldehyde sulfoxylate
5 g. citric acid
10 g. thiourea
S g. aluminum sulphate
6 g. sodium citrate
1 g. cupric sulphate
63 ml. silicone fluid
25 ml. silicone resin, and
37 ml. phenol (88%).
The invention will be described in more detail hereinafter
with reference to the specific examples. It will be appreciated that
there are three objectives of the treatment according to the present
invention (a) dehydration of the blooms, (b) preservation of colour,
and (c) protection of treated blooms.
It is known that in order to preserve a bloom all water must
be eliminated from the bloom. It is also known that many monohydric
alcohols, and in particular tertiary butyl alcohol, are extremely
efficient dehydrating agents. Although any one or more such dehydrat-
ing alcohols may be used we have found that a mixture of tertiary butyl
alcohol, l-propyl alcohol and 2-propyl alcohol is particularly effective
for the treatment of flowers. The tertiary butyl alcohol (all
- 4 -
L9So
~ ol~ffo~7
proportions hereinaEter are per litre of treating~ n, unless
~~~ otherwise stated) can vary from 175 ml. to 575 ml. with a preferred
concentration of about 375 ml. Generally, the more tertiary butyl
alcohol relative to the other two alcohols, the shorter the period of
time of immersion and vice versa. The dehydrating properties of terti-
ary butyl alcohol are so considerable that the final product bloom tends
to be brittle if not compensated by the inclusion of a silicone fluid,
such as Microfil ~ MV-diluent, in the formulation. The upper limit of
tertiary butyl alcohol, relative to the l-propanol and 2-propanol is
controlled at least in part by the fact that tertiary butyl alcohol
free~es at 24C.
The l-propanol and 2-propanol components are in themselves
effective dehydrants and tend to modlfy the harsh effects of tertiary
butyl alcohol used above, without interfering wlth its effectiveness.
The amount of these components i~ not critical to the formulation pro-
vlded modifications to the other components are al~o made.
Sodium phosphate dibasic or other alkalina phosphate, such as
potassium or ammonium phosphate is added to the formulation to control
or buffer the pH. It has been found that pH control of the formulation
i8 necessary for conslstent results and preferably the pH should be in
the range 6.0-6.5. If no green i9 present in the bloom to be treated
the pH may be as low as 5 and pH 7 is preferred for the treatment of
green. It will, of course, be appreciated that most blooms to be treated
will include a green stem and for this reason alone the preferred pH
will be in the range 6.0-6.5.
Sodium or other alkaline formaldehyde sulfo~ylate is optional-
ly added to the formulation for its bridging properties and is particul-
arly useful in the treatment of white blooms. It tends to speed up the
setting of the colour and although omission thereof does not cause any
essential change in results, the overall quality of the preserved blooms,
especially white blooms is reduced.
A carboxylic acid is employed primarily as a colour preservative
~Q~Lg~
for red, pink, yellow and white. Suitable acids include tartarlc acid,
butyric acid, salicylic and carbolic acid, and citric acid is preferred.
Although the amount can be varied widely between the limits descrLbed
hereinabove, a carboxylic acid such as citric acid cannot be eliminated.
Too low a concentration causes the colours to appear faded, especially
in red flowers. Too high a concentration can cause burning or coLour
changes, particularly in the green portions of the flower.
A urea-containing compound is an essential COnStitUellt to prè-
vent loss of pigments from the blooms and, when used together with citric
acld a1,ld sodium citrate, it increases the efflclency of those chemicals
o~Os~f~
and prolongs the active life of thei_~L.$i3R. Thiourea is a preferred
urea-compound. Insufficient thiourea or other urea-containing compound
causes the colours to appear dead and lacking in their original fresh
beauty, and some colours may even change completely, as for instance a
blue orchid ma~ turn a slckly red or pink. Exce~lve thiourea is not
believed to have any deleterious effect except to increase the cost of
the formulation.
Aluminum sulphate is an optional constituent in the formulation
which appears to affect the overall quality of the colours of the blooms.
Too much aluminum sulphate (more than 100% excess) may cause spots resembl-
ing burns on red and blue petals. Magnesium sulphate may also be employed
but tends to be hygroscopic.
Sodlum or other alkaline cltrate i8 added as a colour preserva-
tive for blue, purple and orange blooms and is used in conjunction with
thiourea. Omission of sodium citrate causes the colours to appear faded.
Excess sodium citrate does not appear to affect blue, purple or orange
- blooms but red and pink blooms are adversely affected.
Cupric or other transitional metal (Fe, Ni) sulphate is an
optional constituent added not only to fix the colour of the blooms but
also to draw away moisture which gathers at the bottom of the treatment
tank through repeated treatment of the blooms, thereby extencling the life
C~p~s~hon
of the ~ ~P~e~. Excess of cupric sulphate tends to fall to the bottom
~l~9~1~51D
of the tank undissolved but there is some risk of burns to the blooms.
A silicone fluid, such as a silicone rubber injection com-
pound sold under the trademark Microfil~ (MV-diluent~ by Canton Biomedical
Products Inc. of Boulder, Colorado or dimethyl siloxane polymer sold
under the trademark Dow Corning 200 by Dow Chemical Corp., is added
to the formulation to fulfil the thlrd objective of the treatment, namely
to protect the final product from humidity and temperature. The silicone
fluid als~ has the effect of reducing the brittleness of the bloom caused
by the use of the alcohol dehydrating agents. The silicone fluid
impregnates the tlssue of the blooms as it is being preserved and also
tends to strengthen the petal-torus ~unction. Reduction of the silicone
fluid below about 30ml./1. results in visibly inferior products but an
excess of the silicone fluid has no visible eEEect and merely increases
the cost of the formulation.
In order to further protect the preserved bloom against
humidity and improve the water repellancy thereof a silicone resin such
as Microfil ~ MV~132 Clear which is a silicone polymer sold by Canton
Biomedical Products Inc. or SYL-OF ~ Dow Corning Fluid 1107, may be incor-
porated. It is stressed that neither the siliconefluid or polymer play
any part in the colour preservation of the blooms but they do affect the
physical properties involved in the resistance of the blooms to withstand
mechanical and environmental stresses, essentially rough handling, humidity
and temperature.
Phenol is preferably added to the formulation to enhance
the efficiency of the other constituents. It appears to act as a pH
buffer, as a dehydrating agent and to aid in locking in the colours.
It is stressed that many of the solid compounds in the
formulation are insoluble or only sparingly soluble in the organic liquids
in the composition and tend to settle out. It is improper, therefore,
to refer to a solutio~'which would imply complete dissolution. Although
not wishing to be bound by this explanation it is believed that the solid
components enter solution by way of the water extracted from the blooms
as dehydration thereof proceeds, as explained in more detail hereinafter.
~1 - 7 -
, ~
,i,,~
~o~
The process to treat the blooms according to the present
invention is quite simple and straightforward. A 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 hereinabove is contained in a suitable bath or container at
a temperature in the range of about 45-70F. The bloom is left suspended
in the composition for from 6 to 24 hours without any agitation, depending
upon size and water content of the bloom and the freshness of the composition.
Upon immersion in the composition substantially all colour appears to
disappear from the petals as dehydration occurs under the action of the
dehydrating alcohols. The colour slowly returns to the normal pre-treatment
level as the solid colour fixers and the like take up the extracted water
and actively enter so}ution thus giv:Lng a useful indication oE the treatment
time required. Large, fleshy blooms ~equire longer period of immersion
and care must be taken to ensure thebloom is immersed sufficiently long
to treat the relatively heavy and impervious torus. Following the immersion
treatment thebloom is removed from the composition and air dried at room
temperature 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 ~-6 months at least)
provided the temperature and humidity conditions are suitable (i.e. up to
about 80F and 60-70% relative humidity). More stressful environmental
conditions require that the blooms be stored in sealed glass domes,
where they will likely last for years, or be further coated. It has been
found that dipping or spraying with a conformal coating resin, such as
Dow Cornin ~ R~3117 Silicone Resin alone or diluted with Dow Cornin ~
Fluid 200 (at 0.65 centistokes) or any other diluent, is satisfactory for
this purpose. Preferably the coating is applied by dipping the bloom
into the resin thinned with a diluent such as xylene at a temperature
in the range 50-80F for a few minutes, The coated bloom is then dried
at room temperature for several hours to cure the resin coating. The
resin cures to a clear, transParent, shiny coating and leaves the bl~oom
-- 8 --
,,
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 coating has a bearing on the
appearance of the bloom --thin coatings lend a natural and delicate
appearance to the bloom9 while thick coatings make for sturdy blooms
often of special beautyO 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 temperatures up to 85F
with only slight colour fading. Under more norrnal conditions the
colours remain unaltered.
Example 1
A series of preserving compositions ~ere prepared using
mLxtures of tertiary butyl alcohol, l-propanol and 2-propanol to which
the following components were added and at least partially dissolved,
in sequence so as to maintain the pH of the composition throughout mixing
in the range 6-6.5; dibasic sodium phosphate, sodium formaldehyde sulfoxylate,
citric acid, thiourea, aluminum sulphate, sodium citrate, cupric sulphate,
Microfi ~ MV-diluent, Microfil~ MV 132 Clear, and phenol, in amounts per
litre as set forth in Table I:
T
o _ __ __ _ . __. _ ~,
C ~ ~n ) I_ O~ ~n 1- ~n ~ ~_ O O ~
.._ __ _ ___ _ . _ __ . . _
Il ~ ~n ~ I_ ~ 0~ ~n ~..
o ~ ~ ~ o o ~ 3
. o~ o~ ~ ~ ~o o ~ ~3
_ _ __ _ ~ o o ~ =.~
I IH I 1 ~ 0~ 1-- ~¦ ~ ~ ~ ~ I O O ~1 O
I _ ~ ~n ~> I_ a~ o o ~n ~ I_ O O ~ O
__ _
~ ~n ~ I_ o~ ~ O ~n ~ I_ O oo ~ O
_ _ __
~ ~ ~ 1~ ~ ~1 ~1--I ~ 1~ O~ 0 ~n ~
1- ~ ~ ~ - ~ ~1 ~1 ~ ~ ~ o o~ ~n ~0
l ~ ~ ~ o ~ ~ o ~ ~ o o~ ~ ~3
1- ~ ~ ~ ~ ~1 ~ ~ ~ ~ ~ o ~ ~ ~o
I I- ~n ~ _ ~n O ~n r~ ~- 0 O ~ ~ ~0
_ o~ _ a~ I_ ~ ~1 _ _ _ _ o -- h~
W ~ O ~ ~ ~n O ~n ~ ~_ O 0 ~ O
_ _ ._ _ _ _ .. _ _._ _
i _ ~ O ~ I_ ~ ~n I ~ ~ ~ ~_ ~ ~ ~ W,~~
-- 10 --
5~
E~ample 2
Red roses, white and yellow chrysanthemums, blue and red
fuchsia, yellow and pink hibiscus, red flowering maple, blue african
violet and white and red geraniums were each preserved in each of
compositions A-R as set forth in Table I hereinaboveO The stems of
individual blooms were wired and the blooms suspended in the preserving
compositions at room temperature (~5-70F) for periods ranging from
6-24 hours depending on the size and water content of the bloom and the
freshness of the preserving solution. In some cases it was necessary to
attach a weight to the wire to ensure total immersion of the bloom in the
composltion. After the immersion treatment the blooms were removed from
the solution and air dried at relatively low humidity (preferably less
than 50~) for 8 to 10 hours. If higher humiditles are encountered it may
be necessary to take speclal steps to avoid reabsorption of water, such
as by immersion in a resin such as Dow Cornin ~ R~13117 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
results are set forth in Table II.
-- 11 --
~ ~)
L9S~
_ ---v _ _ _ _ _ _ _ _ _
~ .o ~ ~ ~3: ~ 7~ ,, w c~ ~ ~ _ n w __ ~ q
= _ = _ _ _ _ _ = = = -= _=-- _
O ~ O ~ ~ O O O O O O ~D O ~ O ~ P.
~3 n r~ s _ _ _ _ _ _ _ It o
OoO ~ O Oo~ 04 O O ~Oq ~D~ 04 n ~ ~
. . _ _ _ _ ~ _ , , li _
O n ~ ~ 8 o o o ~o oO tDp~ ~ ~ ~ ~ n o~ ~ ~D
~s _ _ _ _ _ _ o~ ==~ c ~:
O O O O P~ P, rr O ID 1~ ~ P~ O O C C
O O .. _ O _ _ _ ~r _ . C- _ O C ~'
¦ ¦~ c c c ~ ~ n O O C O O O n O ~D O ~D C C C ~D
H tD ~ ._ _ M _ _ _ _ _ _ rr _
1' O S rr O C ~ O O O O pr ,~ ~ r r ~D ~ C ~ ~D
rr rr ~:~' 1~ P CS
pO P~ n ~ ~) Oq ~ g O O O O P~ ~0 rn Pn~ n ~ C '=
rr r C _ CL 00 __ _ n _ _ _ = _ ~ C
C C Itl t P. O M O Pl O 1:~. n e ~ tt
~D C =' _ _ _ _ `~: _ _ ~t
o~O~ oOq ~loq ~o ~ /J~o~ ~o tlo4 ~ C 1~} ~ ~oOq OC ~;e'
~ ~ C~ ~ tD ~ r D. ID `d ~ ID ~Ct ~ rr p
_ _ _ _ _ _ _ _ . I
O O ooq O oo O O ooq P~ O O n U~ ~D
1:~. ~ ~ ~ ~ (D ~ ~ ~ ~ p rt
- - - - - - - . - - -
Olo~ Ooq ooq ooq O olo~ O o~o~ P~ Oq t n ~ o~
~ ~ ~ P. ~ ~ ~r ~~D C~ ~ ~t P
12 ~`
5~
From Table II it can be seen that composition A is a preferred solution
for universal use. Modifications thereto can, of course, be made for
treatment of specifically coloured blooms. Thus, elimination of sodium
phosphate (composition B) results in relatively anemic flowers oE all
colours, additional sodium formaldehyde sulphoxalate (composition C)
is deleterious to yellow, red and blue flowers but appears beneficial
to white flowers. Increasing citric acid (composition D) damages blue
violets and fades yellows but enhances red flowers. Decreasing thiourea
(composition E) fades all colours to some extent but in particular dark
blue violets, while increasing thiourea (composition F) serves no useful
purpose. Increasing aluminum sulphate (composition G) causes spotty red
and blue flowers as it appears to cause a burning Ln the cellular structure
of the petals, reductlon of aluminum sulphate (composition 1l) has little
noticeable effect. Reduction of sodium citrate (compositLon J) causes
fading of the blues and increasing sodium citrate (composition K) has
no noticeable effect as most of the increase appears not to dissolve.
Reduction of cupric sulphate (composition L) had little effect on the
blooms but turned the stems light in colour, while increasing cupric
sulphate (composition M) merely resulted in undissolved chemical
without effect on the blooms. It is believed however that excess cupric
sulphate improves the aging properties of the composition as it appears to
draw water from the alcohols. Reducing phenol (composition N) faded both
red and yellow flowers and excess phenol (composition P) enhanced all
blooms, especially red up to about 62 ml./l. but amounts in excess of
this caused darkening indicating a burning effect. Additional silicone
oil or resin (compositions Q and R) had little effect on the colour or
texture of any of the blooms but lengthened the dehydrating times, due,
it is believed, to the isolating properties of these compounds.
It will be appreciated that many modifications to composition
and process of the present invention may be effected by those skilled
in the art without departing from the scope and ambit thereof. For
example, it has been found possible to add the dehydrating alcohol or
- 13 -
~c~9~gs~
alcohols to a mixture of the other components of the composition, with
excellent results. This is advantageous from the point of view of market-
ing and transportation as the bulk of the composition comprises the
alcohol component and it may be preferable to obtain a suitable alcohol
locally and mix it with a suitably packaged mixlture of the remaining
constituents.
- ]~4 -
