Flocked foam with embossed pattern

A flocked foam having an embossed pattern provided by a high-frequency welder is disclosed. The foam comprises a partially cross-linked foam substrate (10 to 75% gel fraction in boiling toluene for 15 hours) formed from a 1,2-polybutadiene resin or a polymer blend including a 1,2-polybutadiene resin as one component thereof, and modacrylic pile fibers or a mixture thereof with other pile fibers flocked on the surface of the foam substrate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a highly elastic and soft flocked foam which 
presents a pattern apparently having great depth and which has very good 
handle. More particularly, this invention relates to flocked foam having a 
sharp embossed pattern provided by a high-frequency welder and which 
consists of ridges and recesses of different colors (different hue) or of 
the same color but with different color depth (different tone of the same 
hue). 
2. Description of the Prior Art 
Artificial suede leather imitating natural buck skin and flocked goods 
having a handle and appearance made to resemble such artificial leather 
has been gaining acceptance in various applications such as garments, 
furniture and wall coverings. Various products have been developed, such 
as a soft flocked foam which comprises a soft substrate foam composed of 
plastic or rubber which is flocked with short synthetic fibers, typically 
made of rayon or nylon, to combine the softness of the substrate with the 
touch of the flock (also referred to as pile fibers) to provide good 
handle. Virtually none of the currently available rubber foams are ideal 
as a substrate for flocking. For example, soft polyvinyl chloride (PVC) 
and soft polyurethane foams commonly available in the market do permit 
flocking, but they have a number of defects when they are used as 
substrates for flocking. 
The soft foam of PVC is produced by foaming a plasticizer-containing paste 
which can withstand a temperature of only about 70.degree. C., and when 
such an adhesive for flocking is heat-cured or baked, the foam softens and 
fuses. To prevent this, an adhesive that can be heat-cured at a relatively 
low temperature, and which hence permits the use of low baking temperature 
is used (e.g., at 125.degree. C. for 10 minutes; the soft PVC foam is 
generally lined with a layer of cloth that is sufficiently heat-resistant 
to withstand the baking temperature). But this method does not 
successfully provide a flocked product having satisfactory resistance to 
rubbing. While such a soft PVC foam substrate can be flocked in such a 
manner that a pattern comprising high ridges and deep recesses is 
provided, the platicizer oozes out of the substrate to cause various 
undesirable results, such as reduced bond strength between the flock and 
the substrate, toxicity of the plasticizer and the flocked product 
becoming hard at low temperature. The reduced strength of the bond between 
the flocks and the substrate causes many flocks to come off entirely or 
from the edges of ridges during an embossing operation. In addition, the 
smallness of the degree to which the soft PVC foam can expand often 
results in cracking occurring at the edges of ridges. For these reasons, 
such soft PVC foam can only provide an embossed flocked product of low 
quality which has no commercial value. 
The soft polyurethane foam is generally an open-cellular foam which is 
composed of a resin having a three-dimensional structure, which therefore 
precludes embossing with heat. Furthermore, due to the absence of a skin, 
the binder enters the open cells and it is substantially at the cell walls 
that the foam is flocked, providing a flocked product that is low in 
fastness to rubbing. For these reasons, soft polyurethane foam is 
generally not capable of providing a flocked product suitable for 
embossing. 
Other soft foams include a sponge of vulcanized rubber. But vulcanized 
rubber is intrinsically a heat-set product and is not amenable to 
embossing with heat. Besides, it is not used in a continuous sheet. 
Therefore, vulcanized rubber is not suitable for use as a substrate for a 
flocked foam product of this invention. 
A foam is generally provided with an embossed pattern by passing it through 
hot rolls, pressing it with a hot press, or by treating it with a 
high-frequency welder. Hot rolls cannot provide a sharp, intricate and 
fine pattern. Using a hot press requires heating to a high temperature and 
cooling before demolding; hence, the cycle, consisting of setting the foam 
in a mold, heating it under pressure, and then cooling and demolding, 
takes an extended period of time, making quick embossing impossible. The 
use of a high-frequency welder is advantageous over these methods, in that 
it can quickly provide a sharp fine pattern in relief at a low 
temperature. 
Embossing with a high-frequency welder makes use of the following 
principles: When an insulating material having polar groups in the 
molecule thereof is placed in an electric field of high-frequency, a 
periodic current flows to force the polar molecules into motion, such as 
rotation or vibration, thereby generating heat of friction between 
molecules. This means a work piece generates heat within itself, which 
enables even a thick-walled article to be heated quickly and uniformly 
throughout the depth of the article. The amount of heat generated varies 
with the type of work piece, the shape of the electrodes, the spacing 
between electrodes, the high-frequency voltage used, and the frequency 
used. 
In using a high-frequency welder, a mold engraved with a desired pattern is 
fixed between electrodes contained in two parallel press plates, a work 
piece, such as a flocked foam, is placed so as to contact the engraved 
side of the mold, the press plates are closed and oscillated at high 
frequency for a short period of time (generally a few seconds), and the 
mold is removed to leave a foam having an embossed pattern on the flocked 
surface. Loss of the embossed pattern (i.e., return to original shape) can 
be prevented by cooling the mold to a temperature slightly lower than the 
softening point of the substrate resin of the foam before it is demolded. 
The usual method to shorten the overall welding cycle is to maintain the 
parallel press plates at a temperature slightly lower than the softening 
point of the foam substrate resin. In other words, the temperature 
elevated by high-frequency heating is reduced by cooling. Thus, embossing 
with a high-frequency welder uses the heat generated by the motion of the 
molecules of the resin, and that heat plasticizes the resin by elevating 
its temperature to higher than the softening point, at which the resin can 
be processed into a desired shape. It is therefore necessary that the 
resin be thermoplastic. A prerequisite for embossing is that the resin 
softens to a degree sufficient to work it into a desired shape 
(insufficient softening causes the loss of the pattern obtained in 
relief). The term "welding" as used herein means that adjacent portions of 
two or more thermoplastic resins are melted and bonded together by 
applying pressure. Thus, "welding with a high-frequency welder" as used 
herein means that the thermoplastic resins are melted by heating with a 
high-frequency welder, and then pressure is applied thereto to bond the 
thermoplastic resins. In this regard, the joined portion of the 
termoplastic resins are melt-bonded and unified completely. In welding 
thermoplastic resins, the resin must have a melting point such that it can 
be welded to another object because this phenomenon is necessary for the 
melting of the resin with heat and bonding to another object in the fused 
portion. The term "embossing" as used herein means that a pattern of 
ridges and recesses is provided to a foam substrate (or foam sheet); that 
is, the foam substrate is softened by heating and the softened foam cells 
are compressed and broken by applying a pressure and thereby a desired 
pattern of ridges and recesses is set on the foam substrate. 
Most of the soft rubber foams and soft plastic foams that are 
conventionally used as substrates for flocked foam are not amenable to 
welding or embossing with a high-frequency welder. Of the two soft 
aforementioned foams, only the soft PVC foam can be welded or embossed 
using a high-frequency welder (but as also mentioned before, a 
commercially acceptable flocked PVC foam has not been produced thereby). 
The foam of 1,2-polybutadiene resin or a polymer blend containing such a 
resin as one component thereof generally precludes welding with a 
high-frequency welder, but it can be embossed with the machine. The reason 
is the 1,2-polybutadiene resin or the polymer blend containing such a 
resin as one component thereof is partially cross-linked before foaming, 
and the resulting foam retains some degree of thermoplasticity. Therefore, 
when heated, it softens but does not melt completely. Thus, it can be 
embossed but cannot be easily welded with a high-frequency welder. This 
property can advantageously be used for providing a flocked foam with an 
intricate pattern having more than one different level. If the resin is of 
such a nature that it can be welded, all stamped portion of the resin 
(i.e., a recess) melt to lose shape and the very small difference in the 
levels between a ridge and a recess is lost. In addition, the foam loses 
elasticity and becomes rigid. 
As mentioned already, general purpose soft polyurethane foam with a dense 
three-dimensional structure does not soften and hence, it cannot be 
embossed. 
Even if the foam substrate for flocking is amenable to embossing, the 
formation of an embossed pattern having well defined ridges and recesses 
is impossible if the flock materials to be impregnated in the substrate 
are not amenable to embossing. For example, rayon fibers, which do not 
soften to fuse under heating, or nylon fibers having high softening point 
(e.g., nylon stable softening at 180.degree. C. or higher, and the 
filament of nylon 66, which softens at 230.degree. to 235.degree. C.) or a 
high melting point (e.g., the staple of nylon 6 melts at 215.degree. to 
220.degree. C., and the filament of nylon 66 at 250.degree. to 260.degree. 
C.). The term "soften to fuse" as used herein means softening but not 
melting (i.e., heating to a temperature range of between higher than a 
softening point and lower than a melting point), and does not include the 
heating of the resin and/or the flock material to a temperature higher 
than its melting point that would cause welding of the resin and/or the 
flock material. If they are embossed at higher than their melting points, 
the resin and/or flock material solidify and become rigid upon cooling 
after the melting. This results in a product which is hard only in the 
recesses and has its flocked (i.e., sueded) surface impaired. 
SUMMARY OF THE INVENTION 
According to this invention, a flocked foam prepared by flocking a foam 
substrate comprising 1,2-polybutadiene resin or a polymer blend including 
a 1,2-polybutadiene resin as one component thereof with specific flocks of 
modacrylic fibers is provided with an embossed pattern consisting of 
ridges and recesses of different colors (i.e., different hue) or of the 
same color but with different color depths (i.e., different tone of the 
same hue). This treatment can be accomplished with a high-frequency welder 
within only a few seconds. The foam comprises a partially cross-linked 
foam substrate (10 to 75% gel fraction in boiling toluene for 15 hours) 
formed from a 1,2-polybutadiene resin or a polymer blend including a 
1,2-polybutadiene resin as one component thereof. The difference in color 
(hue) or in depth of color (tone) between the ridge and recess provides 
the embossed pattern with a great degree of apparent depth. In addition, 
the resulting flocked foam has satisfactory handle. The foam of this 
invention is from 0.8 to 10 mm thick, has a foaming ratio (i.e., the 
volume after forming:volume before foaming) of from about 3:1 to 20:1, and 
preferably from 5:1 to 10:1 (compare this value with the foaming ratio of 
soft PVC foam which is as low as 2:1 to 3:1), and thus the depth of 
recess, the number of different levels, and the handle are easily 
controlled.

DETAILED DESCRIPTION OF THE INVENTION 
In contrast to the prior art, a foam of a 1,2-polybutadiene resin or a 
polymer blend containing such a resin as one component thereof according 
to this invention is free from the defects described above. Instead, it 
has a high degree of softeness and elasticity and presents good draping 
and insulating characteristics. A flocked product of this foam has very 
good handle and gives comfortably when touched or trod. A substrate foam 
which can be directly flocked with flocking material is a prerequisite for 
providing a long flocked foam which is suitable for use as carpet, wall 
covering, ceiling covering and other interior decorative materials used in 
long lengths. Needless to say, such long flocked foam presents an economic 
advantage in that it can be employed, without producing many waste pieces, 
as a material for small articles which require cutting to form a suitable 
shape. 
The invention is more particularly described hereinafter by reference to 
the drawings. 
FIG. 1 is a perspective view of an embossed flocked foam comprising a soft 
polyvinyl chloride resin. FIG. 2 is a schematic enlarged sectional view of 
the part of the foam cut between the line I--I of FIG. 1. In the figures, 
101 is a foam substrate made of a soft polyvinyl chloride resin, and 102 
is rayon flocks (i.e., flocking material) or nylon flocks. As shown, the 
flocked foam provided with an embossed pattern by roll embossing comprises 
a recess 103 and a ridge 104 where all flocks 102 stand erect, and the 
embossed pattern lacks apparent depth and sharpness. The foam substrate 
melts to such a degree that it loses its inherent flexibility and 
softeness, and the resulting product is not commercially acceptable. 
FIG. 3 is a perspective view of one embodiment of the flocked foam provided 
with an embossed pattern according to this invention. FIG. 4 is an 
enlarged schematic sectional view of the part of the foam cut between the 
lines I--I of FIG. 3. In these figures, 1 is a substrate composed of the 
foam of 1,2-polybutadiene resin or a polymer blend containing such resin 
as one component thereof, and 2 is flocks made of modacrylic fibers. 
As illustrated in FIGS. 3 and 4, this invention is a flocked foam which has 
on its surface an embossed pattern (e.g., of floral and lattice design, or 
any other suitable design) which is imparted by a high-frequency welder. 
The embossed pattern comprises recesses 3 and ridges 4 that have great 
difference in level and, as will be described hereunder, have different 
colors (different hue) or have the same color of different depth 
(different tone of the same hue), and help present the pattern with a very 
clear-cut contour. Such flocked foam with an embossed pattern can be 
produced by intermittently supplying an unpatterned flocked foam material 
[as schematically illustrated in FIG. 5(a), 6(a), 7(a), 8(a) or 9(a)] into 
a high-frequency welder which carries a mold having a surface engraved 
with a desired pattern, and by pressing the mold against the flocked 
surface of the material to achieve embossing simultaneously with the 
formation of two different colors (different hue) or the formation of 
different depths of the same color (different tone of the same hue). 
The flocked foam illustrated in FIG. 3 is provided with an embossed pattern 
of floral and lattice design by treatment with a high-frequency welder in 
the manner described above. As schematically shown in FIG. 4, the flocks 
21 in the recess 3 that has been pressed with the mold soften to fuse with 
each other and come flat, but the flocks 22 on the ridge 4 remain 
uncrushed by the mold and stand erect. In addition, since the flocks 21 in 
the recess 3 are softened and fused to the substance, they have high 
resistance to scratching and will not soon return to upright position. 
Therefore, the flocked foam provides a beautiful sueded surface having 
apparent depth, with the recesses 3 where flocks lie flat being deep in 
color (deep tone) and the ridges 4 where flocks stand erect being light in 
color (light tone). In the recessed portion of the substrate 11, adjacent 
cell membranes are fused to each other, leaving cells crushed to some 
degree, but on the other hand, because of the partial cross-linking of the 
substrate, a considerable number of cells remain uncrushed, and they are 
simply deformed under compression. Therefore, although the recessed 
portion 3 of the foam substrate 11 is less cellular than the ridged 
portion 12 of the substrate, it still remains highly soft and elastic and 
exhibits good cushioning properties, producing good handle. The good 
handle is partly due to the use of flocks comprising modacrylic fibers 
from about 0.5 to 1.5 mm long and from 0.7 to 3.0 deniers thick, which 
match the foam substrate best. 
The flocked foam of this invention is also characterized by an embossed 
pattern having recesses that penetrate deep into the foam substrate 11, as 
shown in the drawings, and which greatly differ in level from the ridges. 
It can be easily understood that the great difference in level between 
ridges and recesses combines with their difference in color (different 
hue) or difference in the depth of color (different tone) to provide an 
embossed pattern which has a great degree of apparent depth under visual 
observation. In contrast, if flocked paper or cloth is subjected to 
high-frequency embossing, the pressed part of the paper (or cloth) loses 
the original handle, become rigid, and the difference in level between 
ridges and recesses is so much smaller than that in the embossed foam of 
this invention that the resulting pattern lacks apparent depth. 
EXAMPLE 
A coating of two-pack cross-linkable polyurethane adhesive of solvent type 
was applied with a reverse coater to a foam made of a 1,2-polybutadiene 
resin available from Japan Synthetic Rubber Co., Ltd. under the trade name 
"RB 820". The foam had a foaming ratio of 5:1, a thickness of 1.0 mm and a 
width of 1 m. The foam was then laminated with a piece of cloth (rayon 
jean). A doctor knife was used to apply the coating of a reactive acrylic 
ester adhesive of emulsion type (available from Teikoku Kagaku Sangyo Co., 
Ltd. under the tradename of "Teisan Resin A-250") to the foam in a dry 
weight of about 100 g/m.sup.2. The foam was flocked with short dyed 
modacrylic fibers (1.0 mm long, 2.0 deniers in thickness, available from 
Kanegafuchi Chemical Industry Co., Ltd. under the trade name "Kanekaron") 
by the down-method (voltage: 45,000 volts, flocking rate: 5 m/min). In the 
"down-method", pile fibers (flocks) fall from a position above the foam 
substrate to be flocked; while falling, the fibers pass through an 
electric field and are thereby charged electrostatically and then the 
charged fibers are flocked on the upper surface of the foam substrate. The 
foam was fed into a drying oven where it was preliminarily heated at 
90.degree. C. for 5 minutes and baked at 135.degree. to 140.degree. C. for 
10 minutes to have the flocks firmly set in the foam. The foam was cooled 
and brushed to remove excess flocks. It was then subjected to embossing 
with a high-frequency welder (made by Yamato Rinita Co., Ltd.) to provide 
a desired raised pattern: a zinc mold having one surface engraved with the 
desired pattern was fixed to the upper plate of a high-frequency press 
having electrodes incorporated therein. The press plates were pre-heated 
to 80.degree. C. and the mold to the same temperature. The temperature was 
equal to the softening point of the foam and it was high enough to prevent 
the loss of the shape (i.e., return to original shape) once imparted to 
the foam. The flocked foam was supplied to the position right under the 
mold, the press plates were closed and pressurized (ram pressure: 100 
kg/cm.sup.2), and immediately thereafter, they were oscillated at 27.1 MHz 
for a certain period (generally in the range of from 2 to 5 seconds) and 
cooled to the mold temperature which was maintained for 2 to 3 seconds. 
The press was opened and the foam now provided with an embossed pattern 
was fed forward by a mold pitch (the period of the embossing cycle was 
generally about 10 seconds). Such intermittent embossing operations using 
known techniques to avoid the formation of a visible boundary between 
repeated unit patterns, provided a flocked foam having an embossed pattern 
comprising endlessly repeating unit patterns. 
The substrate 1 is made of the foam of a 1,2-polybutadiene resin or a 
polymer blend including such a resin as one component thereof. Such a 
butadiene resin includes various types, that ranges from liquid types 
having low molecular weight to those of high crystallinity having no 
processability. For the purposes of this invention, a 1,2-polybutadiene 
resin that contains more than about 70% of 1,2-bonds, has a molecular 
weight of more than 100,000, a crystallinity of from 10 to 50%, and more 
than 20% of syndiotactic stereo-specificity is preferred in view of its 
high heat stability, processability and light-sensitivity properties. 
Details of this type of foam are described in U.S. Pat. Nos. 4,144,153 and 
4,142,956. The 1,2-polybutadiene resin may be blended with a polymer which 
is preferably miscible with the resin and has a softening point relatively 
close to that of the resin. Examples of such polymers include vinyl 
acetate/olefinic, vinyl alcohol/olefinic, and acrylic ester/olefinic vinyl 
copolymers containing more than about 10 mol% of a polar component such as 
vinyl acetate. A polymer blend containing such polar polymer provides a 
foam which is suitable for embossing with a high-frequency welder and 
which can be embossed in a reduced embossing cycle. Particularly preferred 
polar polymers are vinyl acetate/olefinic polymers, and vinyl 
acetate/ethylene copolymer is most preferred. A polymer blend containing 
the last mentioned copolymer provides a foam having very good handle which 
is best suited to embossing with a high-frequency welder. Such polymer is 
preferably blended with the 1,2-polybutadiene resin at a weight ratio of 
from 3:7 to 7:3 (based on the weight of the resin). If the content of the 
polar polymer is too low, the improvement in the suitability of the 
resulting foam to embossing with a high-frequency welder is not as great 
as desired, and if the content is too high, the resulting foam loses the 
original handle and becomes sticky. If desired, another polymer may be 
incorporated additionally in the blend to provide a foam having controlled 
handle. Suitable examples of such additional polymer are those which are 
miscible with both the 1,2-polybutadiene resin and the polar polymer and 
which have a softening point relatively closer to those of these polymers; 
they include polyolefins such as polyethylene, polypropylene and 
polybutene. Such additional polymer is used in an amount of from 0 to 30 
parts by weight per 100 parts by weight of the 1,2-polybutadiene resin or 
a polymer blend thereof with the polar polymer. 
The above-described 1,2-butadiene resin or a polymer blend having such 
resin as one component is foamed by a known method to provide the foam 
substrate for use in this invention. Since the 1,2-polybutadiene resin is 
sensitive to ultraviolet radiation, a foam is preferably prepared from 
such resin by first partially cross-linking it in the form of a mixture 
with other additives such as blowing agent (to such a degree that the gel 
fraction is 10 to 75% in boiling toluene for 15 hours as described in U.S. 
Pat. Nos. 4,144,153 and 4,142,956) and then decomposing the blowing agent. 
This foaming is specifically described hereunder: A mixture of the above 
defined 1,2-polybutadiene resin or polymer blend thereof with a 
photosensitizer and a blowing agent, and optionally an anti-aging agent or 
colorant is continuously extruded from an extruder to provide a thin 
continuous sheet. The sheet is irradiated with ultraviolet rays (240 to 
400 .mu.m) in a short period of time at a controlled dose rate to provide 
a partially cross-linked 1,2-polybutadiene resin. The sheet is then heated 
to higher than the decomposition point of the blowing agent to provide an 
expanded foam. The foaming ratio and handle of the foam can be controlled 
by varying the amounts of the blowing agent and the photosensitizer used, 
the dose of ultraviolet radiation, and other foaming conditions. A 
preferred foam for use in this invention has a thickness of 0.8 to 10 mm, 
more preferably from 0.8 to 5 mm, and most preferably from 0.8 to 1.5 mm. 
The foaming ratio is in the range of from 3:1 to 20:1, preferably from 5:1 
to 10:1. 
The pile fibers to be used in this invention that comprise modacrylic 
fibers generally have a softening point of about 150.degree. C., but they 
soften at about 120.degree. C. to the degree necessary for embossing or 
providing the desired shape. They do not have a sharp melting point. The 
relatively low softening point, the absence of a sharp melting point, and 
susceptibility to high frequency because of the presence of a high 
proportion of polar groups in the molecule are very advantageous 
properties for providing a flocked foam with good handle and well-defined 
and complex embossed patterns. Therefore, with all the above 
characteristics being taken into account, the foam of 1,2-polybutadiene or 
a polymer blend including such a 1,2-polybutadiene resin as one component 
thereof can be flocked with modacrylic fibers and subjected to embossing 
to provide a flocked foam with an embossed pattern that has been 
unobtainable with the prior art. 
The flocks to be used in this invention can comprise modacrylic fibers that 
are made from a long-chain polymer containing 35 to 85% of acrylonitrile. 
From the viewpoint of the ease of embossing, modacrylic fibers having a 
great degree of polarity and which soften at low temperature are 
preferred. Typically, such modacrylic fiber consists of 35 to 85% of 
acrylonitrile and 65 to 15% of vinyl chloride. Both monomers are polar 
components that can make a fire-retardant fiber of long-chain polymer. A 
particularly preferred fiber comprises 50% of acrylonitrile and 50% of 
vinyl chloride. Such fiber generates a large amount of internal heat in an 
electromagnetic field at high frequency and it softens at a temperature as 
low as about 150.degree. C. When it is subjected to embossing with a 
high-frequency welder, the flocks in the area pressed by the welder 
adapter or the projecting portion of the mold (i.e., the recess in an 
embossed pattern) soften to fuse together in only few seconds, and all of 
the flocks become flat. To provide a flocked foam with good handle the 
flocks to be used should comprise the longest and finest possible 
modacrylic fibers, but the fact is such ideal fibers are hard to obtain. 
Therefore, this invention preferably uses modacrylic fibers having a 
length of about 0.5 to 1.5 mm and a thickness of about 0.7 to 3.0 denier. 
Flocks comprising fibers of such dimensions match the softness and 
cushioning properties of the sheet substrate, and provide a product with 
hand feeling as it if were composed of much longer flocks. Such effect can 
be obtained neither from longer and thicker flocks or from shorter and 
finer ones. 
There is no particular limitation on the method of flocking modacrylic, 
nylon or rayon fibers, and a conventional method can be used in this 
invention. According to one example, a coating of a flocking adhesive, 
such as a reactive polyacrylic ester emulsion, that forms strong bond with 
the foam substrate is applied to the surface of the substrate with a 
suitable tool, e.g., doctor knife, in a dry weight of from about 50 to 200 
g/m.sup.2. The substrate is flocked with modacrylic, nylon or rayon fibers 
electrostatically by either the previously mentioned down-method or the 
up-method at a voltage higher than about 30,000 volts. In the up-method, 
pile fibers are electrostatically charged and then flocked on the lower 
surface of the foam substrate, being attracted to the substrate due to 
electrostatic force. The foam is dried preliminarily at from about 
80.degree. to 110.degree. C. for from about 5 to 6 minutes before it is 
baked at from about 110.degree. to 145.degree. C. for a period of from 
about 2 to 10 minutes. The substrate need not be flocked throughout and it 
is to be understood that only a desired part of its surface may be coated 
with a flocking adhesive and flocked with piles. 
The endless flocked foam wherein the foam substrate made of the above 
defined 1,2-polybutadiene resin or polymer blend having such resin as one 
component is impregnated with the flocks described above is supplied 
intermittently into a high-frequency welder that carries a mold having a 
surface engraved with a desired pattern, and the mold is pressed against 
the flocked surface to thereby provide the desired pattern in relief. In 
particular, modacrylic flocks that contain a polar component generate 
internal heat and obtain the temperature necessary for embossing in a very 
short period of time. Therefore, an embossing operation generally requires 
from several seconds up to several tens of seconds. All frequencies for 
the high frequency welder can be used (e.g., 27.12 MHz, 40.46 MHz and 
41.14 MHz permitted in Japan under the Radio Wave Control Low of Transport 
Ministry can be used), and the power output may be selected from the range 
of from 1 to 100 kilowatts depending upon the area of the recess in the 
desired pattern in relief. 
This invention is hereunder described in greater detail by reference to the 
first to fifth embodiments thereof. For the purpose of clarity, the figure 
numbers keyed to the respective embodiments, the substrates and the flocks 
used in the embodiments are set forth in the following table. 
TABLE 
______________________________________ 
Embodiment 
FIG. 
No. No. Substrate Flocks 
______________________________________ 
1 5 the foam of 1,2- 
modacrylic fiber 
polybutadiene 
resin or a 
polymer blend 
containing the 
same as one 
component 
2 6 the foam of 1,2- 
modacrylic fiber; and 
polybutadiene 
flocks that do 
resin or a not soften to 
polymer blend 
fuse with high- 
containing the 
frequency welder 
same as one 
component 
3 7 the foam of 1,2- 
modacrylic long 
polybutadiene 
fiber; and 
resin or a short flocks 
polymer blend 
that do not 
containing the 
soften to fuse 
same as one with high- 
component frequency welder 
4 8 the foam of 1,2- 
long modacrylic 
polybutadiene 
fiber; and 
resin or a short modacrylic 
polymer blend 
fiber having 
containing the 
different color(hue) 
same as one that long one 
component 
5 9 the foam of 1,2- 
long modacrylic 
polybutadiene 
fiber; and short 
resin or a modacrylic fiber 
polymer blend 
of the same 
containing the 
color(hue) 
same as one 
component 
______________________________________ 
FIG. 5 shows the first embodiment of this invention. FIG. 5(a) shows an 
unpatterned flocked foam which comprises a substrate 1 made of the foam of 
a 1,2-polybutadiene resin or a polymer blend containing such resin as one 
component, said substrate being covered uniformly with flocks 2 of 
modacrylic fiber by a flocking adhesive 5. FIG. 5(b) is an enlarged 
schematic sectional view of a flocked foam embossed with a high-frequency 
welder to provide a raised pattern of floral and lattice design. As shown 
schematically in FIG. 5(b), the substrate 1 gives in a portion 3 which is 
pressed by the embossing mold in the high-frequency welder, and forms a 
deep recess in the substrate. As a result, the flocks 21 in the recess 3 
soften to fuse with each other and become flat, but the flocks 22 on the 
ridge 4 remain uncrushed with the mold and stand erect. Therefore, the 
resulting flocked foam provides a beautiful suede surface having different 
tones of color, with the recesses 3 where the flocks 21 lie flat being 
deep in color (generally, the erect flocks cast a shadow depending upon 
their height and make the recesses look deep in color (tone), but in the 
recesses one sees only the lateral side of flat flocks, and depending on 
the direction from which light come, they may appear lighter in color 
(tone) than the erect flocks; this is often observed in a suede surface 
and it produces an interesting variation in tone which is often considered 
attractive by consumers) and the ridges 4 where the flocks 22 stand erect 
being light in color (tone). This contrast in tone, coupled with the great 
difference in level between the ridge 4 and the deep recess 3 in the 
substrate, provides a flocked foam sheet of high commercial value that is 
provided with a clear-cut pattern having apparent depth under visual 
observation. 
FIG. 6 shows the second embodiment of this invention. FIG. 6(a) shows an 
unpatterned flocked foam which comprises a substrate 1 made of the foam of 
a 1,2-polybutadiene resin or a polymer blend containing such resin as one 
component, said substrate is flocked with a uniform pile mixture 25 by a 
flocking adhesive 5. The pile mixture 25 comprises flocks 23 of modacrylic 
fiber and flocks 24 that are of different color (hue) than the flocks 23 
and which do not soften to fuse with a high-frequency welder. The flocks 
23 and flocks 24 are of substantially the same length, and the overall 
pile layer produces a color just between the color of the flocks 23 and 
that of the flocks 24. 
When such flocked foam material is subjected to embossing with a 
high-frequency welder, both the substrate 1 and flocks 23 produce internal 
heat, and as shown in FIG. 6(b), adjacent cell membranes in the part of 
the foam substrate 1 that has been pressed with the projecting portion of 
the mold fuse with each other to crush some cells to thereby form a recess 
11 in which flocks 23 soften to fuse and lie flat. As a result, only 
flocks 24 that do not soften to fuse with the high-frequency welder remain 
erect in the recess 11, and the flat flocks 23 that are substantially 
concealed by the erect flocks 24 are hardly visible. This results in the 
color of the erect flocks 24 which is substantially intensified over the 
color of the flocks 23 in the recess 11 (but depending on the mixing ratio 
of flocks, the color of flat flocks may be intensified). In contrast, the 
flocks 23 on the ridge 12 which have not been pressed by the mold do 
soften to some degree as a result of internal heat generation, but they 
remain erect because they are not affected by the mold. This means that 
both flocks 23 and 24 stand erect on the ridge 12 and present a color 
which varies little from the color produced by mixing their colors before 
the embossing treatment. 
In the way described above, this invention uses a high-frequency welder to 
achieve embossing simultaneously with the changing of the color (hue) of 
the flocks in the recess 11, and provides a flocked foam with a raised 
pattern which comprises the ridge 12 having the color obtained by mixing 
the flocks 23 and 24 and the recess 11 having the color of the flocks 24 
substantially intensified over the color the flocks 23. As a result, the 
recess 11 is sharply distinguished from the ridge 12 on the boundary, thus 
providing a two-colored pattern in relief with a clear-cut contour. 
It is to be understood that neither flocks 23 nor 24 are limited to those 
of a single color (hue); each of them may comprise more than one set of 
flocks having dissimilar colors to enable fine adjustment of the color. 
The flocks 24 that do not soften to fuse with a high-frequency welder are 
made of synthetic fibers, such as rayon or nylon fibers, having 0.5 to 1.5 
mm long and 0.7 to 3.0 denier. For details of the application of the 
coating of an adhesive, flocking of pile fibers and the embossing with a 
high-frequency welder, see Example described hereinabove. 
FIG. 7 shows a third embodiment of this invention. 
FIG. 7(a) shows another flocked foam material for use in this invention, 
and it is so constructed that when it is embossed with a welder, the 
resulting recess and ridge portions present far greater contrast by color 
difference (hue difference) than obtained using the foam material shown in 
FIG. 6(a). The foam material of FIG. 7(a) is identical to the material of 
FIG. 6(a) except that the flocks 23 of modacrylic fiber are longer than 
the flocks 24 that do not soften to fuse by a high-frequency welder. With 
such material, the long flocks 23 substantially conceal the short flocks 
24, providing a flock layer wherein the color (hue) of the long flocks 23 
is substantially intensified over the color (hue) of the short flocks 24. 
FIG. 7(b) shows the flocked foam of this invention that is produced by 
embossing such flocked foam material with a high-frequency welder. Like 
the product shown in FIG. 6(b), both the piles 23 and 24 stand erect on 
the ridge 12, whereas only the flocks 24 that do not soften to fuse by the 
welder stand erect in the recess 11. As a result, in the ridge 12, the 
color (hue) of the long flocks 23 is substantially intensified over the 
color (hue) of the flocks 24, and in the recess 11, only the color (hue) 
of the erect piles 24 is visible, thus providing an ever sharper pattern 
with a higher contrast between the colors (hues) of the recess 11 and 
ridge 12. If the flocks 24 that do not soften to fuse by high-frequency 
are longer than the flocks 23, a pattern with low contrast between the 
colors (hues) of the recess and ridge is produced. 
The above-described third embodiment of this invention uses a substrate, 
pile fibers and flocking adhesive each identical with what is used in the 
first and second embodiments. For details of the application of the 
coating of an adhesive, flocking of the pile fibers and the embossing with 
a high-frequency welder, see the Example described hereinabove. 
FIG. 8 shows a fourth embodiment of this invention. FIG. 8(a) shows a 
flocked foam material which comprises a substrate 1 made of the foam of 
1,2-polybutadiene resin or a polymer blend having such a resin as one 
component; said substrate if flocked with a pile mixture 28 by a flocking 
adhesive 5. The pile mixture consists of long flocks 26 of modacrylic 
fiber, and short flocks 27 of another modacrylic fiber having a different 
color (hue) than that of the flocks 26. The short flocks 27 are 
substantially concealed by the long flocks 26 and are hardly visible. As a 
result, the overall flock layer is such that the color (hue) of the long 
flocks 26 is intensified over the color (hue) of the short flocks 27. 
When such flocked foam material is subjected to embossing with a 
high-frequency welder, both the substrate 1 and the pile mixture 28 
produce internal heat, and as shown in FIG. 8(b), adjacent cell membranes 
in the part of the foam substrate 1 that has been pressed with mold 
partially fuse with each other to crush some cells to thereby form a 
recess 11 in which the pile mixture 28 softens to fuse and become flat. If 
the pile mixture 28 in the recess 11 becomes flat, the short flocks 27 
that have been hardly visible to the eye come to be exposed between long 
flocks 26. Hence, the flock layer in the recess 11 assumes the color (hue) 
produced by mixing the colors (hues) of the long flocks 26 and short 
flocks 27. On the other hand, the pile mixture 28 on the ridge 12 which 
has not been pressed by the mold do soften and fuse to some extent as a 
result of internal heat generation, but it still remains erect and retains 
the original color (hue) of the flock layer (i.e., the color (hue) before 
the embossing). 
In the way described above, this invention uses a high-frequency welder to 
achieve embossing simultaneously with the changing of the color (hue) of 
the flocks in the recess 11, and provides a flocked foam with a raised 
pattern which comprises the ridge 12 having the color (hue) of the long 
flocks 26 and the recess 11 having the color (hue) obtained by mixing the 
long flocks 26 with the short flocks 27. As a result, the recess 11 is 
sharply distinguished from the ridge 12 on the boundary, thus providing a 
two-colored pattern (two hues) in relief with a clear-cut contour. 
It is to be understood that neither flocks 26 nor 27 are limited to those 
of a single color (hue); each of them may comprise more than one set of 
flocks having dissimilar colors (hues) to enable fine adjustment of color 
(hue). 
The above-described fourth embodiment of this invention uses a substrate, 
pile fibers and flocking adhesive each identical with what is used in the 
first embodiment. For details of the application of the coating of an 
adhesive, flocking of the pile fibers and the embossing with a 
high-frequency welder, see the Example described hereinabove. 
FIG. 9 shows a fifth embodiment of this invention. FIG. 9(a) shows a 
flocked foam material which is identical with the material shown in FIG. 
8(a) except that short flocks 27 have the same color (hue) as that of the 
long flocks 26 to provide a surface flock layer having the single color 
(hue) of the long and short flocks 26 and 27. When such flocked foam 
material is subjected to embossing with a high-frequency welder, both the 
flocks 26 and 27 in the recess 11 become flat as they soften to fuse with 
each other, but those on the ridge 12 remain erect. As a result, the ridge 
12 having erect flocks 26 and 27 is velvety and presents a relatively 
light color (light tone) as they were before the embossing treatment, 
whereas the recess 11 where the flocks 26 and 27 lie flat presents a deep 
color (deep tone) due to the high flock density. This way, the recess 11 
is sharply distinguished from the ridge 12 on the boundary, providing an 
embossed pattern with a difference in color depth (different tone) and a 
clear-cut contour. 
The above-described fifth embodiment of this invention uses a substrate, 
pile fibers and flocking adhesive each identical with what is used in the 
Example described hereinabove. For details of the application of the 
coating of an adhesive, flocking of the pile fibers and the embossing with 
a high-frequency welder, also see that Example. 
As described in the foregoing, this invention provides for the first time 
in the industry an endless flocked foam having good handle and a sharp 
suede pattern in relief comprising ridges and recesses of different colors 
(different hues) or of the same color but with different color depth 
(different tones of the same hue), thus having a great degree of apparent 
depth. Such foam is produced by embossing a substrate foam of a specified 
material flocked with fibers of a specified material with a high-frequency 
welder. Said foam product can be produced on an industrial scale with high 
efficiency. Modacrylic fibers comprising a vinyl chloride-acrylonitrile 
copolymer used as the flocking fiber are fire-retardant, and the foam 
produced using them is suitable for use in construction materials such as 
wall covering, floor coverings and ceiling coverings, coverings for 
furniture such as chairs, as well as garments, bags, footwear and other 
miscellaneous household goods. 
It is to be understood that the terminology "embossed pattern, raised 
pattern or pattern in relief" as used herein is not limited to geometric 
and non-geometric figures; it includes all types of figures, designs, 
letters and symbols. It is also to be understood that the flocked foam of 
this invention is not limited to those specifically illustrated in the 
accompanying drawings and that various modifications and variations (such 
as those lined with substrate fabric) can be made without departing from 
the scope and spirit of the invention. 
While the invention has been described in detail and with reference to 
specific embodiments thereof, it will be apparent to one skilled in the 
art that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.