Note: Descriptions are shown in the official language in which they were submitted.
~03839~
Process for ~he manufacture oP laminates
~.
The present invention relates to a process ~or the
manuPac~ure o laminates from a syn~hetic resin-impregna~ed
base ply and one or two absorben~ outer plies~
In.our copending application Ser.No. 263.3~6,
~iled october 14, 1976~ a process or ~he manufacture o~
laminates ~or ski componen-~s, especially those or Porming
~he upper or lower outer ply, which consi~ o~ a ~iber~rein-
Porced base ply ~ a thermose~tin~ synthetic resin, which ~-
has been obtained by polymeriæat~on or polyaddi~ion, and
at least one outer ply based on absorbent material, the
plies being joined to one another unde~ pressure, and whilst
curing the the~mosetting ~ynthetic resin is described and
claimed in which process at least one ply o the absorbent
mater~al is pressed onto the base ply, which is in a precured
form, ~nd which contains 40 - 70% oP a thermo~etting synthetic
resing the low o~ the said resin ~ the said base ply being
between 10 % and 60 %~ measured under a pressure of 5 kp/cm2
at ~50~C~ over a period o~ 10 minutes, and the ply or plies oP
th~ absorbent materia} are completely impregnated by the resin
available rom the base ply, and ~ll plies are joined to one
another and Pully cured.
In the case oP thicker ~nd mul~i-ply b~se plies this
leads to increasin~ losses oP resin~ since the resin i5
squeeæed out "
It has now been Pound that~ when multi-ply base
p1ies are used for the manufacture oP la~inates, the losses
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o~ resin can be greatly redueed iP only those plies of the
multi ply base material, on Y~hich the absorben~ materials rests
directly, are provided with the high resin con~ent and the large
resin ~low, but the plies o~ ~he base ply which ~ie underneath
are not provided therewith.
The subject o~ ~he present invention is, thus, in a
process ~or the manuacture o~ l~minates ~or ski components,
which laminates con~ist essentially of a iber-rein~orced base
ply o~ a thermosetting synthetic resin, obtained by polymeri-
satlon or polyadd~tion and at least one ou~er ply based on anabsorbent material~ ~he plies being joined to one another under
pressuxe while curing the resin in a combined pre~sing and
curing step, the impro~ement ~hich comprises, in said combined
pressing and curing step, pressing at least one ply o$ the
absorbent material onto the base ply~ which base.ply c0~5ists
o~ at least two ~iber reinorced plies in precured ~or~n~ o~ which
plies the upper one, which lies directly under the ab~orbent ma-
terial contains 40 - 70~ o~ the resin, the ~low o said resin
in ~aid ply ~eing be~ween 10/~ and 60% and the lower one or ones ~ :
contai~ 20 - 40% o~ the resin, the flow o$ said resin in ~aid
lower ply or plie~ being between 1% and 9%, said ~low being
measured under a pressure o~ 5 kp/cm~ at 150C over a per:iod
o~ 1~ minutes, ~hereby the ply or plies o the absorben~ ma-
terial become completely impre~na~d by ~he res~n available
~rom the upper ply o ~he base ply, and all the plies are
joined to one another and Eully cured to orm a lamina~e havin~
smooth ou~er sur~ace.
Woven fabrics, leeces or other fibrous products~ which
form the outer plies o the base ply, are impregnated with the
requisite amount o~ synthetic resin so that, on pressing in com-
bination with the outer ply, su~ficient a~ailable resin is
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~083939
present to impregnate the outer ply completely and to form
a surface film thereon. In general, 40 - 50/0 of resin
suffice for this purpose. The amount used depends on the
"flow" of the particular resin. This flow must be at least
10% under pressing conditions of 5 kp/cm2 at 150C, with 10
minutes duration, in order to achieve the effect according to
the invention.
Pressing is c'arried out under conventional conditions
for the manufacture of laminates of this type. For example,
it is possible to apply a pressure of about 5 - 15 kp/cm2 at
120 - 160C. `~
The choice of the ratio of resln component to fibrous '
material in the external ply of the base ply is intended to
ensure that on pressing sufficient resin is available to impreg-
nate the outer ply completely and to form a perfect layer of
resin on the surface. The thickness and absorbency of the
outer ply as well as the fluidity of the resin are important
in achieving the object of the invention. By using decorative
webs of paper, fleeces or similar materials, or using colored
20 resins, any desired surface effects can be achieved. '
The individual plies of the base ply consist predomi-
nantly of glass fibers but these can also be replaced entirely or
p~lally by carbon fibres and can be constructed similar to woven
fabrics, knitted fabrics, fleeces or the like, The outer
ply consists, above all, of paper, absorbent fleeces made from
cellulose, cotton or glass, and also a mixed fleece.
Thermosetting synthetic resins, obtained by polymeri-
zation or polyaddition, which should be mentioned are, above
all,'epoxide resins and unsaturated polyester resins, especially
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lL083939
those which are modified with diallyl phthalate.
The thermosetting resins used can have a differen-t
chemical structure which can also result in differen-t flow prop-
erties of the individual plies, for example by braking -the flow
of the base ply and/or assisting that of the outer ply. For
example, this effect is already achieved if, with the same type
of resin, different curing systems are employed, but it is, of ~ ;
course, also possible to vary the nature of the resin itself,
for example by using an unsaturated polyester resin for the
base ply and an epoxide resin for the outer ply, or vice versa~
The advantage of the present invention is that only
one ïmpregnating process is required, even for the manufacture
of thicker laminates, without an uncontrolled effusion of resin
occurring during pressing. The surface of the laminate here
becomes so smooth and perfect -that grinding it, in order to glue
a covering film onto it, is superfluous.
Example 1:
The base ply, a unidirectional glass fiber fabric
weighing 500 g/m2 as ply l, is impr~g~ated with about 35% of
an epoxide resin (prepreg), the resin being formulated to give
a flow of l - 3%. As ply 2, a glass fabric is impregnated
with about 50% of an epoxide resin, the resin being formul~ted
to give a flow of lO - 15%. The two prepregs are pressed
together with an absorbent, colored a-cellulose paper, weigh-
ing 80 g/m2, at about 140C and 5 kp/cm2 in such a way that
the ~-cellulose paper is bonded to the ply 2 and the latter is
bonded to the ply lo The laminate taken out of the press
after it has cooled down again consists of an about 0.85 mm
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33~
, thick GRP ply and an about 0.15 mm thick outer ply.
Example 2:
A unidirectional glass fiber fabric weighing 520 g/m2
is impregnated with an epoxide resin based on the diglycidyl
ether of bisphenol A and diaminodiphenylme-thane as a curing
agent in such a way that a prepreg with a resin conten-t of
35% and a flow of 3% results. A second unidirectional glass
fiber fabric weighing 520 g/m2 is impregnated with an epoxide ~-
resin which is based on the diglycidyl ether of bisphenol A
and which is reacted with dicyandiamide as a curing agent and
dimethylbenzylamine as an accelerator. The resin is formu-
lated to give a content of 45/0 in the prepreg and a flow of
15%.
The two plies are now pressed together with a colored
a-cellulose paper, weighing 160 g, at about 150~ and 5 kp/cm2
coritact pressure in such a way that the a-cellulose paper is
pressed together with the second prepreg which is richer in
resin and more fluid, and the latter is pressed together with `
the prepreg which is lower in resin and less fluid. The
laminate taken out of the press consists of an about 0.8 mm
thick GRP ply and a 0.2 mm thick outer ply.
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