Reinforced foamed resin structural material and process for manufacturing the same

A structural material formed of a fiber and honeycomb reinforced foamed resin is disclosed, which is constructed by arranging a honeycomb material, the voids of which contain a foamable thermosetting resinous liquid, between two fibrous layers and heating the assembly to foam the resinous liquid and simultaneously cover and impregnate the fibrous layers whereby the fibrous layers and the honeycomb material are completely impregnated with and encased in the foamed resin.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a lightweight structural material of a 
reinforced, foamed resin, and to a process for preparing the same. More 
particularly, the present invention relates to a structural material 
constructed of two surface layers each of which comprises fiber reinforced 
foamed resin, and a core layer provided therebetween which combines or 
merges with the surface layers to form a single body, and to a process for 
preparing such an article. 
2. Description of the Prior Art 
Hitherto, various shaped articles of foamed resins have been proposed. For 
instance, there have been known foamed resins reinforced by covering the 
surface thereof with asbestos slates or metal plates, or by dispersing 
fibers thereinto. However, when asbestos slates are employed, the articles 
are weak in impact strength and exhibit poor workability, for example, 
when they are cut with a saw. On the other hand, in the case of metal 
plates the articles also have poor workability. In addition, a 
sufficiently lightweight cannot be attained in either case. When the 
surface of a foamed resin is covered with a synthetic resin plate 
reinforced with fibers, the impact resistance of the article is not 
sufficiently high because of the rigid surface. Further, satisfactorily 
high compression strength and good workability also cannot be attained. 
In addition to the above-described foamed resin materials, plate-like 
shaped articles having a sandwich construction are known in which for 
example fiber reinforced resin plates (abbreviated as FRP) are used as a 
surface material and honeycomb materials are used as a core material. 
These articles show poor workability on sawing, planing and nail-driving 
because of the rigidness of the FRP employed as a surface material. It is 
difficult to render these articles lightweight because, while the core 
materials contained therein are lightweight, the combined use of the FRP 
increases their respective specific gravities. These articles are also 
weak in impact strength. Articles utilizing foamed resins as core 
materials suffer from the defect that they are easily deformed by 
compressive stress, and the articles suffer from the defect that they are 
weak to certain stresses, especially bending stress because the junction 
between the surface material and the core material is small. 
On the other hand, foamed resins reinforced by dispersing fibers therein 
are excellent in impact resistance, workability and bending and 
compression strength. One example of a foamed resin fiber reinforced 
material is described in U.S. Pat. No. 4,025,257 and Japanese patent 
application (OPI) No. 107360/76 (The term "OPI" as used herein refers to a 
"published unexamined Japanese patent application"). However, as the 
foaming magnification increases, the foams communicate with one another at 
the interfaces of the resin foams with fibers contained therein and water 
absorption tends to occur. Consequently, an increase in weight and a 
decrease in heat insulating ability due to water absorption tend to take 
place and a problem arises. Though it is necessary to limit the foaming 
magnification to a low level under these circumstances, low magnification 
is undesirable from the standpoint of providing lightweight and economical 
articles. 
U.S. Pat. No. 3,917,774 discloses a continuous process and apparatus for 
preparing an elongated foamed resin article reinforced by continuous 
fibers in which continuous fibers are advanced in parallel relationship in 
a sheet-like form and are impregnated with a liquid composition capable of 
forming a foamed thermoset resin. The impregnated fibers are then passed 
through a gathering means which gathers the fibers into a bundle having a 
cross-section approximating that of the desired article thereby uniformly 
dispersing the liquid composition in the fibers. The bundle of fibers is 
then advanced through a movable molding passage of three or more endless 
belts arranged parallel to each other so as to form a passageway which has 
a cross-section perpendicular to the direction of advancement of the 
bundle of fibers corresponding to the desired cross-section of the 
article. The belts contact and move with the impregnated bundle of fibers. 
SUMMARY OF THE INVENTION 
In view of the foregoing one object of the present invention is to provide 
a structural material which is not only lightweight but also excellent in 
various properties required for a construction material, such as impact 
resistance, compression strength, bending strength, heat insulating 
ability, waterproof, reagent proof, workability, etc. 
It is another object of the present invention to provide a process for 
preparing such a material with ease and with high efficiency. 
Another object of the present invention is to provide a reinforced foamed 
resin structural material which is excellent in bending strength 
notwithstanding its relatively small fiber content, and to provide a 
process for preparing the same. 
It has now been found that the above-described objects are attained by a 
lightweight reinforced foamed resin structural material comprising two 
surface layers constructed of foamed resin reinforced by fibers and a core 
layer provided therebetween wherein the layers are combined into a single 
body and the core layer is constructed of a material having a honeycomb 
structure the voids of which are charged with a foamed resin. 
Further, the objects of the present invention are more effectively attained 
by a lightweight reinforced foamed resin structural material as described 
above in which the respective surface layers are constructed of a foamed 
layer reinforced by a highly impregnatable fiber mat and a foamed layer, 
which is laminated thereto on the surface facing the core layer, 
reinforced by a multiplicity of long fibers spread and arranged in a 
specific direction.

DETAILED DESCRIPTION OF THE INVENTION 
The foamed resin materials of the present invention have a variety of 
applications and can be used in particular for heat insulation, for walls 
of houses, for floors, benches and verandas, for loading stands of 
autotrucks, for land and marine containers, core materials for FRP ships, 
etc. 
Reinforced foamed resin structural materials of the present invention are 
described below and illustrated in detail in the drawings. 
FIG. 1 is a cross-section of one embodiment of the material of the present 
invention, in which core layer 2 is provided between surface layers 1 so 
as to form a single body together with the two surface layers. The surface 
layer 1 is constructed of a foamed resin reinforced by fibers, and the 
core layer 2 is made of a honeycomb material 21 in which a foamed resin 22 
charges the voids of the honeycomb material 21. 
FIG. 2 is a cross-section of another embodiment of the material of the 
present invention, in which the surface layer 1 has a dual layer structure 
constructed by the foamed layer 11 which is reinforced by a fiber mat, and 
the foamed layer 12 which is reinforced by a multiplicity of long fibers. 
In addition, the fiber mat reinforced foamed layers 11 are arranged so as 
to become the outermost layers of the material respectively. 
FIG. 3 is a cross-section of a further embodiment of the structural 
material of the present invention, wherein an aggregate 23 is present in 
the resin charging the voids of the honeycomb. 
Specific examples of fibers which constitute the surface layers of the 
present invention and function as reinforcing materials include highly 
impregnatable materials made of glass fibers, natural fibers, synthetic 
fibers, metallic fibers, carbon fibers and so on. These fibers may be 
employed in the form of short fibers 5 mm to 10 cm in length, long fibers 
more than 10 cm in length, a woven fabric such as a glass cloth or a woven 
net of fibers, a layer in which the fibers are arranged in planar parallel 
relationship, a nonwoven mat of fibers such as a chop-strand mat, a 
continuous strand mat, glass-paper, surface mat, etc. A nonwoven 
glass-paper, and surface mat are reinforcing materials which are made of 2 
to 10 cm single fibers. The former is produced by a so-called wet process 
using an emulsion binder such as a polyvinyl acetate emulsion and a 
polyacrylate emulsion. The latter is produced by a so-called dry process 
without the use of an emulsion binder, using a hot-melt process. Of these 
fibers, glass fibers are the most preferred from the standpoint of the 
strength and the price of the article obtained. Preferably the fibers are 
employed in the mat form. 
Preferable fibers have such a high capacity to be impregnated with various 
liquids that the fibers can be spread in a layer and impregnated with 
foamable thermosetting resinous liquids with high permeabilities, and such 
that a liquid resinous material can penetrate into the inner fiber layer 
by merely sprinkling it over the surface of the fiber layer and further 
can pervade the fiber layer upon expansion resulting from foaming of the 
resinous liquid. Thus, foamed resins reinforced by fibers wherein the 
fibers are completely and uniformly dispersed in the foamed resin can be 
easily obtained when highly impregnatable fibers as described above are 
employed and foamable thermosetting resinous liquids are supplied to the 
fibers by a simple sprinkling treatment or the like followed by foaming 
and setting of the resinous liquids. In this manner special apparatuses 
for impregnation of resinous liquids are not necessary. 
The porosity of such highly impregnatable fibrous materials range from 
about 50 to 97 volume % voids, preferably from about 80 to 95 volume % 
voids. A glass cloth typically has about 90 volume % voids. As a specific 
example of the most preferable highly impregnatable fibrous material, 
mention may be made of a continuous strand mat as described in U.S. Pat. 
No. 3,394,046. This mat is prepared by laminating a multiplicity of 
continuous long glass fibers in one or more layers as the fibers are 
revolved in a vortex and then combining fibers in superposed areas 
utilizing adhesives previously adhered to the fibers to shape a mat. The 
continuous strand mat has a far higher capacity (compared with the cases 
of chop strand mat and glass cloth) to be penetrated and impregnated with 
a resinous liquid, and exhibits better fiber dispersibility into a foamed 
resin at the time of foaming and setting of the resinous liquid. Typically 
a mat of this type will contain about 85 volume % voids depending on how 
densely the fibers are laminated. 
The foamed resins constituting the surface layers 1 and the foamed resin 22 
employed for the core layer 2 may be the same or different. Two or more 
fiber layers can also be placed one on top of the other and laminated on 
each side of a honeycomb material as a surface layer. Generally the amount 
of fibrous material in the surface layers range from 10 to 70 volume % and 
preferably from 15 to 60 volume %. 
The foamed synthetic resins employed in the surface layers and core layer 
are not particularly limited. However, from the standpoints of the heat 
resistance required of a construction material and facility in preparation 
of a plate-like shaped article thermosetting resins such as polyurethanes, 
phenolic resins, unsaturated polyester resins, urea resins, melamine 
resins, epoxy resins, etc., are preferred. Of these thermosetting resins, 
foamable thermosetting resinous liquids which can be foamed and set in a 
short period of time are particularly suitable for use in the present 
invention. 
Representative examples of polyester resins are esters obtained from the 
reaction between a dibasic acid such as a maleic acid, fumaric acid, etc., 
and a dihydric alcohol, such as ethylene glycol, diethylene glycol, etc. 
As urea resins, condensation products of ureas and aldehydes may be used 
and as epoxy resins, reaction products of epichlorohydrins and 
bis(4-hydroxyphenol)dimethylmethane may be used. 
A particularly effective process for preparing the structural materials of 
the present invention is performed using a resinous liquid of foamable 
polyurethane, which provides a rigid polyurethane foam. Such a foamable 
liquid contains a foaming agent, a catalyst and a foam controlling agent 
mixed together with a polyol and a polyisocyanate. As a polyol, both 
polyester polyols and polyether polyols may be used. Polyester polyols 
such as obtained from a condensation reaction between a dicarboxylic acid, 
such as adipic acid, suberic acid, sebacic acid, phthalic acid, 
isophthalic acid, terephthalic acid, etc., and a polyhydric alcohol such 
as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 
2,3-butylene glycol, dimethylene glycol, pentamethylene glycol, 
hexamethylene glycol, decamethylene glycol, trimethylolpropane, 
trimethylolethane, glycerin, etc., may be used. Polyether polyols such as 
obtained from an addition polymerization between a polyhydric alcohol such 
as glycerin, trimethylolpropane, pentaerythritol, .alpha.-methyl glucose, 
sorbitol, sucrose, etc., and an alkylene oxide such as an ethylene oxide, 
a 1,2-propylene oxide, a 1,2-butylene oxide, a 2,3-butylene oxide can also 
form the resin. Examples of the isocyanate are a tetramethylene 
diisocyanate, a hexamethylene diisocyanate, an ethylene diisocyanate, a 
xylene diisocyanate, a 1,3,6-hexanetriisocyanate, a phenylene 
diisocyanate, a tolylene diisocyanate, a chlorophenylene diisocyanate, a 
diphenylmethane diisocyanate, a triphenylmethane-4,4',4"-triisocyanate, a 
xylene-.alpha.,.alpha.'-diisocyanate, an 
isopropylbenzene-1,4-diisocyanate, etc. 
As a foaming agent, water or a volatile liquid having a low boiling point 
such as a monofluoro-trichloromethane, dichloro-difluoromethane, 
dichloro-tetrafluoroethane, monochloro-difluoromethane, etc., may be used 
and to control foaming water-soluble silicone compounds or 
polysiloxaneoxyalkylene copolymers are used. A basic salt of a metal of 
Group VIII of the Periodic Table, a tertiary amine and tin compound, etc., 
are generally used as catalysts. 
Of these resinous liquids those providing a rigid polyurethane are 
especially preferred. 
Any honeycomb material is suitable as the core material of the present 
invention as long as it has a planar shape. The honeycomb material is not 
limited in terms of the shape of the honeycomb structure. A cell of the 
honeycomb material is, for example, about 5 mm to 50 mm, preferably about 
8 to 20 mm across but will depend on the size and shape of the structural 
material formed. The materials may have a variety of design constructions 
such as hexagonal, wave-like, and cylinder-like constructions. Specific 
examples of honeycomb materials suitably employed in the present invention 
include conventional honeycomb core materials conventionally used for 
preparing articles having sandwich structures such as paper honeycombs, 
paper honeycombs impregnated with resins such as thermosetting resins, for 
example, polyurethanes, phenol resins, unsaturated polyester resins, epoxy 
resins, melamine resins, urea resins, etc., and thermoplastic resin 
emulsions or solutions, for example, polystyrene, polyvinylacetate, 
polyacrylate, etc.; plastic honeycombs, metal honeycombs and so on. The 
thickness of the honeycomb structure ranges from 5 mm to 99 mm. The 
thickness of the material sheet constructing the honeycomb core ranges 
from about 0.1 to 2 mm, preferably 0.2 to 1 mm. 
In addition, in the present invention aggregates may be incorporated in the 
foamed resin 22 charging the voids of the honeycomb material 21 as 
illustrated in FIG. 3. Specific examples of such aggregates include 
inorganic fillers such as calcium carbonate, talc, aluminum hydroxide, 
etc., lightweight aggregates such as silica balloon, perlite, glass 
balloon, etc., quartz sand, etc. These aggregates are employed to improve 
various physical properties, for example, the compression strength of a 
foamed resin constituting the core layer and to reduce the price of the 
article. The aggregate may be used in an amount corresponding to 5 to 60% 
by volume calculated based on the volume occupied by the core layer in the 
lightweight foamed resin material of the present invention. 
Foamed resin materials having particularly good bending strength can be 
obtained by providing as the surface layer a dual layer of a foamed resin 
reinforced by a highly impregnatable fiber mat, preferably a continuous 
strand mat, and a foamed layer reinforced by a multiplicity of long 
fibers, preferably glass fibers, spread and oriented in one or more 
directions as desired. In the case of the continuous processes illustrated 
in FIGS. 4 and 5 it is convenient and good mechanical properties can be 
obtained by orienting the fiber in the running direction of the work. 
Therein, the extent of the improvement in the bending strength is greater 
than what should be expected from the amount of fibers used. 
The long fibers employed for reinforcement of the foamed layer 12 in the 
surface layer 1 are spread and arranged in a certain direction and include 
glass fibers, synthetic fibers, metallic fibers, carbon fibers, etc. When 
single fibers are used as long fibers, fibers having a thickness of 6.mu. 
to 30.mu., preferably 9.mu. to 20.mu. are spread on the honeycomb material 
at a rate of 50,000 to 450,000 single fibers per meter. In particular, a 
glass roving obtained by assembling a multiplicity of glass fibers and 
then roving them is preferred. Glass rovings are spread on the honeycomb 
material at a rate of 50 to 300 glass rovings per meter. One glass roving 
contains from about 1,000 to 15,000 single fibers. The direction in which 
the long fibers are spread and arranged is generally the lengthwise 
direction of the shaped article which in a continuous manufacture 
corresponds to the running direction. 
Other embodiments of the surface layer of the present invention are 
illustrated in FIGS. 6 and 7. In the surface material of FIG. 6, a foamed 
resin is reinforced by a large number of long fibers 14 dispersed in the 
foamed resin and further by a fiber mat 13 provided in the vicinity of one 
of the surfaces of the foamed resin. In the surface layer of FIG. 7 a 
foamed resin 15 is reinforced by a fiber mat 13 provided in the vicinity 
of both surfaces of the foamed resin. In the present invention, the 
surface layer is about 0.5 to 20 mm thick and preferably about 0.6 to 10 
mm thick. The thickness for the fiber mat reinforcing the surface layer is 
about 0.1 to 10 mm and preferably about 0.2 to 7 mm, and the thickness of 
the long fiber reinforced layer is about 0.1 to 10 mm and preferably about 
0.2 to 8 mm. It will be apparent to the skilled artisan, however, that 
these dimensions may be adjusted depending upon the size and shape of the 
structural material formed. 
Such surface layers can be prepared with ease by, for example, placing 
first a fiber mat impregnated with a foamable thermosetting resinous 
liquid in a mold and then arranging thereon fibers impregnated similarly 
with the resinous liquid with a prescribed thickness, followed by foaming 
and setting of the resinous liquid in the mold. Another method involves 
applying a foamable thermosetting resinous liquid between two layers of a 
fiber mat impregnated with the same resinous liquid, placing them in a 
mold, and then allowing the resinous liquid to undergo foaming and setting 
in the mold. 
In order to obtain the structural material of the present invention, the 
surface layers and the core layer may be prepared separately (i.e., 
impregnated, foamed and set), and they may be stuck to one other with aid 
of adhesives to form a single body. In this case the adhesives preferably 
have a composition similar to that of the foam resin. A polyisocyanate 
adhesive is preferably used. However, it is more desirable to prepare the 
plate-like shaped article of the present invention in the following manner 
for simplicity and the core layer can be combined more firmly with the 
surface layers to form a single body. A honeycomb material is placed 
between two surface layers to prepare a laminate, a foamable thermosetting 
resinous liquid is supplied to the laminate, and the resulting resinous 
liquid is allowed to foam and simultaneously to set to fill the voids of 
the honeycomb material with the foamed resin and at the same time, to 
impregnate and cover the fibers constituting the surface layers in the 
foamed resin produced. Thus, the surface layers and the core layers are 
combined firmly into a unitary construction. 
FIG. 4 is an illustration of an embodiment of a process of the present 
invention wherein two layers of highly impregnatable continuous fibers 
(e.g., continuous strand mats) 4 and 4' are pulled from their respective 
reels and are advanced in the direction shown by the arrow in layers by 
means of guide rolls 42 and 42', respectively. A honeycomb material 21 is 
also advanced in the direction shown by the arrow and arranged so as to be 
situated between the above-described two layers of fibers 4 and 4'. In 
addition, a conveyor 8 supports and transports the honeycomb material. 
These materials are conveyed and transported to a passage for molding 6 
which has a cross section corresponding to the plate-like shape. The 
passage 6 is constructed of an endless belt 61 corresponding to the upper 
surface, an endless belt 62 corresponding to the lower surface or floor 
and, further, one endless belt which covers both sides of the passage not 
shown in the figure. 62 and 62' are guide rolls for endless belts 61 and 
61', respectively. The passage may be constructed of the endless belts 
alone, but side walls, a ceiling and a floor are preferably further 
provided to obtain a more uniform foam and a smoother article surface. 
The endless belt 61' which forms the floor of the passage 6 is arranged so 
as to extend beyond the inlet opening of the passage 6 in the direction 
opposite to the advancing direction of the honeycomb material and provides 
a location where the honeycomb material is superposed upon the layer of 
highly impregnatable fibers 4', which forms the lower layer of the 
article, and they are supported by belt 61' and transported towards the 
inlet of the passage. A foamable thermosetting resinous liquid is supplied 
to the honeycomb material 21 by means of a resinous liquid supplying 
apparatus 52 from an upper position before application of the fibers 4 
forming the upper surface layer, and it is retained by the voids of the 
honeycomb material 21. With the advancement of these materials a layer of 
the fibers 4 is applied to the upper surface of the honeycomb material 21 
and superposed thereon to produce a laminate, followed by the introduction 
of the laminate into the passage for molding 6. In passage 6 the belts 61, 
61' and the side belts contact and move the resin containing laminate. 
Thereafter the foamable thermosetting resinous liquid is foamed in the 
passage for molding 6. Due to expansion occurring as the result of 
foaming, the voids of the honeycomb structure are filled with the resinous 
liquid and, at the same time, some portions of the resinous liquid 
uniformly permeate the fibers 4 and 4'. Further, due to subsequent setting 
of the resinous liquid the resinous liquid together with the honeycomb 
material 21 and fibers 4 and 4' are formed into a plate-like shaped 
article of a foamed resin reinforced by fibers and a honeycomb material. 
The thus-obtained shaped article is pulled from the passage by a means 
such as a roller conveyor or endless belt (not shown in the figure) and 
cut to a definite size. 
Passage for molding 6 may be equipped with a heating apparatus to 
accelerate the foaming and the setting of the resinous liquid, and a 
cooling apparatus for lowering the temperature after the conclusion of 
foaming and setting phenomenon, etc. 
Passage 6 is usually 2 to 20 meters long and assembled material is in the 
passage for 1 to 25 minutes. Suitable foaming temperatures are about 
0.degree. to 50.degree. C. and preferably 10.degree. to 35.degree. C. 
Generally foaming is completed in 10 seconds to 5 minutes and preferably 
30 seconds to 2 minutes. The setting temperature is usually about 
40.degree. to about 150.degree. C. and preferably 60.degree. to 
120.degree. C. and can be accomplished in 1 to 20 minutes and preferably 2 
to 10 minutes. 
FIG. 5 is an illustration of another embodiment of a process of the present 
invention wherein an endless belt 61 forms the upper surface of the 
passage for molding 6, an endless belt 63 forms the lower surface of the 
passage for molding 6, 62 and 64 are guide rolls for the endless belts 61 
and 63, respectively, and a side frame may be arranged along the sides of 
the lower endless belt 63. Endless belts 61 and 63 travel in the 
directions indicated by the arrows. In addition, the endless belt 63 which 
forms the lower surface of the passage 6 is arranged so as to extend 
beyond the inlet of passage 6 and thereby provide a convenient location 
for placement of the materials to be molded. Glass rovings 3 and 3' which 
are a multiplicity of glass fibers are pulled in the advancing direction 
shown by the arrow from rolls 31 and 31' and via guide rolls 32, 32', 33 
and 34 and arranged horizontally in a parallel relationship at regular 
intervals. In addition, continuous strand mats 4 and 4' are fed from rolls 
41 and 41' to passage 6 via guide rolls 42 and 42'. 
As described above, the combination of a continuous strand mat and a glass 
roving is employed as a fiber material layer in the present invention. 
Therein, the continuous strand mat 4, which is employed for constructing 
the upper surface layer, and the continuous strand mat 4', which is 
employed for constructing the lower surface layer, are arranged so as to 
be situated in the positions corresponding to their respective outermost 
surfaces. On the other hand, the honeycomb material 21 is continuously 
supplied from a location elevated from the passage for molding 6, via 
guide roll 24 and it descends to the surface of the extension of the lower 
endless belt 63 and with the advancement thereof the angle of descent 
decreases and the honeycomb material is not fixed in the vicinity of the 
inlet of the passage for molding 6. It comes into contact with the endless 
belt 63 in the vicinity of the inlet of the passage and is supported by 
the endless belt 63. The above-described honeycomb material 21, glass 
rovings 3 and 3', and continuous strand mats 4 and 4', respectively, are 
advanced in the directions indicated by arrows, and applied so as to form 
a single body at the time of introduction into the passage for molding 6. 
On the way to the passage for molding, namely, where the honeycomb 
material is elevated from the endless belt 63 and does not come entirely 
into contact with the belt, a foamable thermosetting resinous liquid is 
supplied from a foamable liquid-injecting apparatus 51 situated above. 
The resinous liquid supplied in the above-described manner passes through 
the voids of the honeycomb material 21 to fall onto the fiber layer on the 
endless belt 63 and subsequently permeates into such fiber materials. At 
the same time, the resinous liquid flows laterally passing into the space 
between the endless belt 63 and the fiber layer and the honeycomb material 
21 to result in the uniform distribution. Furthermore, the resinous liquid 
gradually flows down the elevated honeycomb material and toward the 
honeycomb material supported by the endless belt 63 to result in the 
uniform distribution to individual interstices making up the honeycomb 
structure of the honeycomb material 21. In the passage for molding, 
foaming of the foamable thermosetting resinous liquid occurs which is 
accompanied by expansion. Due to expansion the voids of the honeycomb 
structure and gaps between the fiber material constituting the lower 
surface layer are completely filled with the foamed resin and, at the same 
time, the foamable resinous liquid penetrates into the fiber materials 
constituting the upper surface layer to encase them in foam. Thereafter, 
setting of the foamable thermosetting resinous liquid occurs to result in 
the production of a plate-like shaped article 7' of the foamed resin 
reinforced by honeycomb material 21, glass rovings 3 and 3', and 
continuous strand mats 4 and 4'. The thus-obtained material 7' is pulled 
from the outlet of the passage for molding 6 by a means not shown in the 
figure and cut into a definite size. 
As can be seen from FIG. 4 and FIG. 5, the supply of the resinous liquid 
may be carried out before or after the application of the fiber material 4 
to construct the upper surface layer on the honeycomb material. Such being 
the case, FIG. 5 shows an embodiment where after the fiber material is 
applied to the honeycomb material, the resinous liquid is supplied to the 
honeycomb material through the fiber material 3 from a place situated 
above the fiber material 3. 
A convenient thickness for the structural material of the present invention 
is from 10 to 100 mm and a specific gravity is 0.2 to 0.8, however, other 
sizes and specific gravities may be obtained depending upon the end use of 
the material. Since the lightweight foamed resin material of the present 
invention has the construction as described above, wherein the surface 
layer is constructed of a foamed resin reinforced by fiber material(s) 
while the core layer is a honeycomb material the voids of which are filled 
with a foamed resin, and these layers are combined into a single body, it 
is lightweight and excellent in the mechanical properties required of a 
construction material, for example, compression strength, bending strength 
and the like, as well as impact resisting peroperty. In particular, due to 
the surface layer constituted by a foamed resin reinforced by fibers, the 
shaped article of the present invention can exhibit such effects that not 
only impacts applied thereto can be absorbed by the foamed resin, but also 
cracks generated are not propagated. In addition, owing to the presence of 
the foamed layer reinforced by long fibers pulled and arranged in one or 
more directions the shaped article of the present invention can 
demonstrate effectively its strength such as bending strength or the like, 
notwithstanding the relatively small amount of fibers used. Further, the 
presence of such a foamed layer serves the purpose of lightening the 
material. Furthermore, the plate-like shaped foamed resin article of the 
present invention is not only excellent in heat insulating ability, 
waterproof and reagent proof but also has good workability. The structural 
materials of the present invention usually have a planar shape. 
Accordingly, the materials of the present invention can be employed 
suitably for construction materials which are required to be light in 
weight, to possess heat insulating property and further, to possess high 
compression strength. Specifically, they can exhibit their abilities when 
they serve as heat insulating materials for walls of houses, floor 
materials, materials for making benches and verandas, materials for 
loading stands of autotrucks, materials for land and marine containers, 
core materials for FRP ships and so on. To facilitate their use in these 
areas the structural materials may be formed on opposite parallel sides 
with an interlocking tongue and groove construction. 
Moreover, on the occasion that highly impregnatable fiber materials are 
used in the present invention, the fiber materials need not be impregnated 
with foamable thermosetting resinous liquid in advance, and it becomes 
possible to impregnate uniformly the fiber material with the resinous 
liquid through the expansion resulting from the foaming of the resinous 
liquid supplied to the honeycomb materials. Therefore, the impregnating 
process and apparatus for impregnating previously the fiber materials with 
resinous liquids are rendered unnecessary in the present invention. Thus, 
in accordance with embodiments of the present invention, foamed resin 
materials possessing excellent properties as described above can be 
prepared simply and effectively. 
In addition, by adopting a special method of supplying the honeycomb 
material and the foamable thermosetting resinous liquid in the present 
invention a structural material can be prepared in which the foamed resin 
is uniformly contained in individual voids of the honeycomb structure of 
the honeycomb material. 
The present invention will now be illustrated in greater detail by 
reference to the following examples. 
EXAMPLE 1 
In a box shaped steel mold having an inside volume 2 cm deep, 10 cm broad 
and 50 cm long and having two holes having a diameter of 0.5 mm in the 
upper mold for the purpose of letting generated gas out of the mold, a 
continuous strand mat (the product of Asahi Fiber Glass Co., Ltd.) 1 mm 
thick having weight of 450 g/m.sup.2 and cut in size of 10 cm by 50 cm was 
spread and then 200 g of foamable polyurethane was poured onto the mat so 
as to become evenly dispersed state. 
The above-described foamable polyurethane was obtained by mixing 150 parts 
by weight of crude diphenylmethane dilsocyanate with a liquid composition 
consisting of 100 parts by weight of polyether polyol having 4 hydroxy 
groups obtained by an addition reaction of propylene oxide, 1.5 parts by 
weight of distilled water, 5 parts by weight of 
monofluoro-trichloromethane, 0.5 part by weight of silicone oil and 0.3 
part by weight of dibutyl tin dilaurate. 
Next, a paper honeycomb (Hatocore, manufactured by Honshu Paper Co., Ltd. 
having an apparent specific gravity 0.04, a thickness of sheet 
constructing the honeycomb 0.6 mm) having the thicknes of 18 mm and cut in 
size of 10 cm by 50 cm was placed on the foamable polyurethane layer and 
thereon a continuous strand mat of the same kind as described above was 
additionally placed. Thereafter, the mold was closed. 
After the foaming of the resinous liquid in the mold was almost completed, 
the mold was placed in a heating oven and the foamed resin therein was 
heated at a temperature of 120.degree. C. for 10 minutes. Thereafter, the 
mold was removed from the oven, chilled with water and then the resulting 
molding was removed from the mold. 
The thus-obtained article had a planar construction and a specific gravity 
of 0.28. The surface layer was constructed of the foamed polyurethane 
reinforced by the continuous strand mat (17.7% by volume) and had a 
thickness of 1 mm. The core layer was constructed of the paper honeycomb 
and the foamed polyurethane. In addition, the bending strength and other 
properties are set forth in Table 1. 
EXAMPLE 2 
A foamed resin structural material was prepared in the same manner as in 
Example 1 except that two continuous strand mats 1 mm thick were employed 
to form both surface layers (4 mats in total), and the quantity of the 
foamable polyurethane used was 225 g instead of 200 g. The specific 
gravity of the article obtained was 0.35. Its physical properties are set 
forth in Table 1. 
COMISON EXAMPLE 1 
Onto a glass roving (weight: 110 g) which was obtained by cutting long 
glass fibers in length of 50 cm and then, by bundling them, was sprinkled 
240 g of the same foamable polyurethane used in Example 1 to result in 
uniform impregnation of the fiber with the polyurethane. The resulting 
glass roving was inserted into a tube-form mold having the inside cross 
section of 10 cm.times.2 cm and length of 50 cm, and the both ends of 
which were open. After the conclusion of foaming, the mold was placed in a 
heating oven, and heated at a temperature of 120.degree. C. for 10 minutes 
to result in the setting of the foamed resin. After cooling the mold, the 
resulting molding was removed from the mold. 
The thus obtained article corresponded to the platelike shaped foamed 
polyurethane reinforced by long glass fibers arranged in the lengthwise 
direction, and had a specific gravity of 0.35. Its physical properties are 
also set forth in Table 1. 
TABLE 1 
______________________________________ 
Physical Properties 
Example 1 Example 2 Comparison 1 
______________________________________ 
Specific Gravity 
0.28 0.35 0.35 
Bending Strength in 
Longitudinal Direc- 
300 kg/cm.sup.2 
400 kg/cm.sup.2 
350 kg/cm.sup.2 
tion (JISZ-2113) 
Bending Elastic 
Modulus (JISZ-2113) 
2.0 .times. 10.sup.4 
3.5 .times. 10.sup.4 
3 .times. 10.sup.4 
kg/cm.sup.2 
kg/cm.sup.2 
kg/cm.sup.2 
Bending Strength in 
Transverse Direc- 
250 kg/cm.sup.2 
350 kg/cm.sup.2 
20 kg/cm.sup.2 
tion (JISZ-2113) 
Compression 
Strength 40 kg/cm.sup.2 
60 kg/cm.sup.2 
15 kg/cm.sup.2 
(JISZ-2111) 
______________________________________ 
EXAMPLE 3 
In a box-form steel mold having the inside volume 2 cm deep, 10 cm broad 
and 50 cm long and having two holes measuring in diameter of 0.5 mm in the 
upper mold part for the purpose of letting generated gas out of the mold, 
a continuous strand mat (a product of Asahi Fiber Glass Co., Ltd.) 0.4 mm 
thick having weight of 450 g/m.sup.2 and cut in size of 10 cm by 50 cm was 
spread, and thereon ten glass rovings (in a combined thickness of 0.6 mm) 
cut in length of 50 cm, each of which consisted of 60 strands, each strand 
corresponding to a bundle of 200 single fibers 9.mu. thick, were arranged 
at regular intervals and further 200 g of foamable polyurethane was poured 
onto the glass rovings so as to form an evenly dispersed state. 
The above-described foamable polyurethane was obtained by mixing 150 parts 
by weight of crude diphenylmethane diisocyanate with a liquid composition 
consisting of 100 parts by weight of polyether polyol having 4 hydroxy 
groups obtained by an addition reaction of propylene oxide, 1.5 parts by 
weight of distilled water, 5 parts by weight of 
monofluoro-trichloromethane, 0.5 part by weight of silicone oil and 0.3 
part by weight of dibutyl tin dilaurate. 
Next, a paper honeycomb (Hatocore, manufactured by Honshu Paper Co., Ltd.) 
having the thickness of 18 mm and cut in size of 10 cm by 50 cm was placed 
on the foamable polyurethane and thereon the same number of glass rovings 
as described above were arranged and further the same continuous strand 
mat as described above was put on the glass rovings. Thereafter, the mold 
was closed. 
After the foaming of the resinous liquid in the mold was almost completed, 
the mold was placed in a heating oven, and the foamed resin therein was 
heated at a temperature of 120.degree. C. for 10 minutes. Then, the mold 
was removed from the oven and chilled with water. Thereafter, the 
resulting molding was removed from the mold. 
Thus, a foamed resin article the surfaces of which were constructed of 
foamed polyurethanes reinforced by fibers (53.8% by volume), as shown in 
FIG. 2, was obtained. The article obtained had the following physical 
properties: 
______________________________________ 
Specific Gravity (measured by the 
0.36 
method described in JISZ-2102) 
Bending Strength (in the longitudi- 
450 kg/cm.sup.2 
nal direction measured by the 
method described in JISZ-2113) 
Bending Elastic Modulus (in the 
3.8 .times. 10.sup.4 kg/cm.sup.2 
longitudinal direction measured 
by the method described in 
JISZ-2113) 
Compression Strength (measured by 
40 kg/cm.sup.2 
the method described in JISZ- 
2111) 
______________________________________ 
EXAMPLE 4 
A plate-like shaped foamed resin article was prepared in the same manner as 
in Example 3 except that instead of 200 g of the foamable polyurethane 
poured into the mold was employed a liquid composition obtained by mixing 
a 200 g portion of a mixture consisting of 100 parts by weight of polyol 
(the same one as used in Example 1), 1.5 parts by weight of distilled 
water, 10 parts by weight of monofluoro-trichloromethane, 0.5 part by 
weight of silicone oil, 0.3 part by weight of dibutyl tin laurate and 150 
parts by weight of purified diphenylmethane diisocyanate with 75 g of 
aggregate (foamed article of glass-clay system which contains as main 
component glass grains having granularity of 2.5 to 5 mm and apparent 
specific gravity of 0.59, trade name OK Raito, manufactured by Chichibu 
Concrete Industry Co., Ltd.). 
The article obtained had the following physical properties, each of which 
was measured by the same method as described in Example 3: 
______________________________________ 
Specific Gravity 0.375 
Bending Strength in the Longitudi- 
450 kg/cm.sup.2 
nal Direction 
Bending Elastic Modulus 
4.1 .times. 10.sup.4 kg/cm.sup.2 
Compression Strength 60 kg/cm.sup.2 
______________________________________ 
EXAMPLE 5 
According to the procedures in FIG. 4, foamed resin structural materials 
were produced. A continuous strand mat (manufactured by Asahi Fiber Glass 
Co., Ltd.) having a weight of 540 g/m.sup.2 and 85 volume % voids was used 
as a fiber mat, and a honeycomb paper (Diacell, manufactured by 
Shin-Nippon Core Co., Ltd.) having a thickness of 18 mm, a width of 170 
mm, a thickness of the kraft paper constructing the honeycomb paper of 0.3 
mm, 95 volume % voids and an apparent specific gravity of 0.022, and 
constructed of hexagonal cores having a side of 12 mm was used as a 
honeycomb material. 
The same foamable polyurethane used in Example 1 was poured into the voids 
of the honeycomb material in an amount of 800 g/min. and then the three 
layers were passed through a molding passage 6 of 9 m length constructed 
by four endless belts made of stainless steel to form a space of a 170 mm 
width and a 20 mm height. After being heated at 120.degree. C. by a heater 
covering about 3 m of the middle part of the molding passage 6, the 
article was removed from the passage by an endless belt at a speed of 1 
m/min. and cut by a circular saw. The article thus-obtained was 20 mm 
thick, 170 mm wide and 4,000 mm long and had the following physical 
properties measured as in Example 1. 
______________________________________ 
Specific Gravity 0.30 
Bending Strength in the Longitudi- 
320 kg/cm.sup.2 
nal Direction 
Bending Elastic Modulus 
2.0 .times. 10.sup.4 kg/cm.sup.2 
Bending Strength in the Traverse 
220 kg/cm.sup.2 
Direction 
Compression Strength 30 kg/cm.sup.2 
______________________________________ 
The article had a 1.0 mm thick surface layer. 
EXAMPLE 6 
According to the procedures of FIG. 5, foamed resin structural materials 
were produced. The same continuous strand mat, honeycomb material, and 
equipment, i.e., endless belts, and molding passage as used in Example 5, 
and the same foamable polyurethane as used in Example 3 were used. 
The glass-roving used was a combination of 60 strands, each strand being a 
multiplicity of 2,000 single glass fibers having a thickness of 9.mu.. 18 
glass rovings were spread on the honeycomb material and the resinous 
liquid was poured thereon in an amount of 480 g/min. 
The article thus-obtained was 20 mm thick, a 170 mm wide and a 4,000 mm 
long, and the layer of foamed resin reinforced by the mat was 0.4 mm thick 
and the layer of foamed resin reinforced by the glass rovings was 0.6 mm 
thick. 
The physical properties of the article are as follows. 
______________________________________ 
Specific Gravity 0.30 
Bending Strength in the 
450 kg/cm.sup.2 
Longitudinal Direction 
Bending Elastic Modulus 
4.0 .times. 10.sup.4 kg/cm.sup.2 
Compression Strength 30 kg/cm.sup.2 
______________________________________ 
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.