Toy vehicle with thermochromic material

A toy vehicle spray painted with paint containing thermochromic material which changes color as the temperature of the vehicle varies. Selected portions of the toy vehicle may be painted with the thermochromic material to provide a variety of patterns, designs, numbers, letters or other indicia which change color in response to temperature variations. In addition, different portions of the toy vehicle may be painted with different paints containing different color thermochromic materials.

BACKGROUND OF THE INVENTION 
The present invention relates generally to toy vehicles and, more 
particularly, to a toy vehicle painted with a paint containing 
thermochromic material which changes color as the temperature of the 
vehicle varies. 
In the past, a variety of toys have been developed with color-changing 
features using thermochromic or light-sensitive materials embedded or 
mixed in plastic, printed on paper or plastic, or impregnated in fibers 
used for clothing, doll hair, plush figures, or the like. For example, 
U.S. Pat. Nos. 4,560,604 issued to Shimizu, et al on Dec. 24, 1985 
(coating fibers used for stuffed toys with thermochromic material); 
4,134,853 issued to Ehrlich, et al on Jan. 16, 1979 (photochromic 
composition combined with moldable materials for forming toys); and 
3,980,300 issued to Hornsby, Jr. on Sept. 14, 1976 (layer of liquid 
crystalline material used for ball) which disclose the use of such 
materials in toys. British Patent No. GB 2,066,089A issued to Rickson on 
July 8, 1981 describes the use of temperature-sensitive cholesteric liquid 
crystal material for changing the color of the eyes of a doll. U.S. Pat. 
No. 3,382,607 issued to Ryan, et al on May 14, 1968 discloses a figure toy 
having synthetic hair fibers impregnated with an indicator dye which 
changes color in response to contact with liquids of different pH 
concentrations. 
Thermochromic materials are disclosed in U.S. Pat. Nos. 4,567,019 issued to 
Lawton on Jan. 28, 1986 and 4,421,560 issued to Kito, et al on Dec. 20, 
1983. Heat-sensitive recording materials are described in U.S. Pat. Nos. 
4,611,072 issued to Nachbur, et al; 4,462,616 issued to Shanton on July 
31, 1984; and 4,444,819 issued to Maruta, et al. 
None of the above patents discloses a toy vehicle painted with a paint 
containing thermochromic material which is capable of changing color as 
the temperature of the vehicle varies. Since the toy vehicle is painted, 
such a toy vehicle, especially a miniature die-cast vehicle, provides 
numerous play options. For example, a child could pretend that such a toy 
vehicle is being painted by immersing it in heated or cold water causing 
the color of the vehicle to change. A child could also vary the color of 
such a vehicle using heated or cold air, ice, heated pens, heated brushes, 
light bulbs, heat blankets, or the heat of his or her hands The toy 
vehicle could be made out of any material such as metal or plastic. 
Accordingly, there is a need in the toy manufacturing arts for such a toy 
vehicle. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a toy vehicle painted with 
paint containing thermochromic material which changes color as the 
temperature of the vehicle varies. 
It is another object of this invention to provide a toy vehicle which is 
spray painted with paint containing thermochromic material. 
It is still another object of this invention to provide a toy vehicle 
having only portions thereof spray painted with paint containing 
thermochromic material to produce a variety of patterns, designs, numbers, 
letters or other indicia which change color as the temperature of the 
vehicle varies. 
It is still another object of this invention to provide a toy vehicle 
having different portions thereof spray painted with different paints 
containing different colored thermochromic materials which change color as 
the temperature of the vehicle varies. 
These and other objects and advantages are attained by a toy vehicle spray 
painted with paint containing thermochromic material which changes color 
as the temperature of the vehicle varies. Selected portions of the toy 
vehicle may be painted with the paint containing thermochromic material to 
provide a variety of patterns, designs, numbers, letters, or other indicia 
which change color in response to temperature variations. In addition, 
different portions of the toy vehicle may be painted with different paints 
containing different colored thermochromic materials. 
The various features of the present invention will be best understood 
together with further objects and advantages by reference to the following 
description of the preferred embodiments taken in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The following specification taken in conjunction with the drawings sets 
forth the preferred embodiments of the present invention in such a manner 
that any person skilled in the toy manufacturing arts can use the 
invention. The embodiments disclosed herein are the best modes 
contemplated by the inventors for carrying out their invention in a 
commmercial environment although it should be understood that various 
modifications can be accomplished within the parameters of the present 
invention. 
Referring now to the drawings and particularly to FIG. 1, a toy vehicle 10 
of the present invention having a body 12 is disclosed. The body 12 is 
painted with paint containing thermochromic material at portions thereof 
to provide a pattern or stripes 14 as illustrated. Alternatively, the body 
12 may be painted with thermochromic material at different portions 
thereof to provide a variety of designs 16, letters 18, numbers 20 or 
other indicia (not shown) as illustrated in FIGS. 2 though 4. In addition, 
the entire body 12 may be painted with paint containing thermochromic 
material if desired (not shown). It is important to point out that any 
portion or all of the body 12 may be painted with paint containing 
thermochromic material to provide any desirable design, pattern, number, 
letter or indicia. 
FIG. 5 shows another embodiment of the toy vehicle 10. The body 12 of the 
vehicle 10 has different portions 22 through 28 thereof painted with 
different paints containing different colored thermochromic materials so 
that each portion has a different colored thermochromic material. 
Alternatively, some of the portions 22 through 28 may have the same 
colored thermochromic material. As another alternative, the thermochromic 
materials of one or some of the portions 22 through 28 may change color at 
different temperatures. 
Since the thermochromic material will change color as the temperature of 
the body 12 changes, a child may vary the appearance or color of the toy 
vehicle 10 by raising or lowering the temperature of the body 12. This may 
be accomplished by immersing the toy vehicle 10 in heated or cold water, 
or using heated or cold air, ice, heated pens, heated brushes, light 
bulbs, heat blankets, etc., to change the temperature of the body 12. The 
heat of a child's hands may also be used to change the temperature of the 
body 12 and, thus, change the color of the thermochromic material. 
Generally, thermochromic material changes color from a darker color to a 
lighter color as the temperature of the material is increased. 
Dramatic results may be obtained by changing the temperature of the body 12 
or thermochromic material. For example, as the temperature changes the toy 
vehicle 10 shown in FIG. 3 changes from a private vehicle to a cab, or 
vice versa. Numerous other changes are possible such as changing a private 
vehicle into a police car, ambulance, etc. A particularly dramatic result 
is obtained if the color of the toy vehicle 10 changes from a color such 
as brown which may be used to simulate a "dirty look" to a lighter, 
brighter, or clear color to simulate a "clean look", thus simulating 
washing the toy vehicle 10. This may be accomplished by using a 
brown-colored thermochromic material which becomes clear or transparent as 
the temperature of the material or body 12 is heated to a certain 
temperature level revealing an underlying coat of paint (or color) which 
does not contain thermochromic material. The same result can be obtained 
by using a thermochromic material which changes from a brown color to a 
lighter color as the temperature increases. 
The body 12 may be made out of any material such as metal or plastic. 
However, a miniature metal die-cast body 12 is preferable because a metal 
vehicle will stay warm or cold longer and, thus, retain its color longer 
than a plastic vehicle. 
The body 12 of the toy vehicle 10 is preferably spray painted with a paint 
containing thermochromic material. Alternatively, the toy vehicle 10 may 
be painted with a paint containing thermochromic material by dipping the 
vehicle in the paint, using a brush to paint the vehicle, or using any 
other technique. The word "painted" as used herein is intended to include 
any means of coating the body 12 of the toy vehicle 10 with a paint 
containing thermochromic material. Likewise, the word "paint" as used 
herein is intended to include any material containing thermochromic 
material that is coated to the body 12 of the toy vehicle 10. Because the 
paint containing thermochromic material is painted onto the body 12, the 
color of the toy vehicle 10 is brighter than that of a vehicle made out of 
molded plastic material containing thermochromic material. In addition, a 
toy metal vehicle spray painted with thermochromic material will retain 
its color longer, or stay warm or cold longer, than a vehicle made out of 
molded thermochromic plastic material. 
The thermochromic material sprayed onto the body 12 is preferably 
thermochromic paint sold by Matsui Shikiso Chemical Co., Ltd., Kyoto, 
Japan, under the trademark Chromic Epoxy Spray Paint. The composition of 
the thermochromic paint sold under the above trademark is a trade secret 
of Matsui Shikiso Chemical Co., Ltd. However, this thermochromic paint 
contains microencapsulated thermochromic material mixed or blended with an 
epoxy resin material, a hardening agent such as that sold by the 
above-mentioned company under the trademark Chromic Epoxy Fixer and a 
diluting solvent such as Xylol (Xylene). The Chromic Epoxy Spray Paint has 
nine base colors: yellow, gold orange, vermilion, pink, fast blue, 
turquoise blue, green, brown and black. Matsui Shikiso Chemical Co., Ltd., 
has developed a method of spray painting the Chromic Epoxy Spray Paint 
onto a toy vehicle by spraying a first coat of the thermochromic paint 
onto the vehicle followed by heat treatment at 140.degree. C. for 5 
minutes, and then spraying a second coat of the thermochromic paint 
followed by heat treatment at 140.degree. C. for 20 minutes. However, any 
number of coats (including only one coat) of thermochromic paint may be 
used and the heat treatment can be varied or eliminated if desired. It is 
important to note that any other type of thermochromic paint may be used 
instead of the above-mentioned Chromic Epoxy Spray Paint and any color 
paint or thermochromic material may be used. Also, the temperature ranges 
during which the thermochromic materials change color can be selected as 
desired. 
The above description discloses the preferred embodiments of the present 
invention. However, persons of ordinary skill in the toy field are capable 
of numerous modifications once taught these principles. Accordingly, it 
will be understood by those skilled in the art that changes in form and 
details may be made to the above-described embodiments without departing 
from the spirit and scope of the invention.