Title of Invention

TEXTILE SEMIFINISHED PRODUCT WITH AT LEAST ONE SURFACE PROVIDED WITH AN ADHESIVE

Abstract The present invention relates to a textile semifinished product with at least one surface provided with an adhesive, wherein the adhesive is immobilized on the surface of the semifinished product in order to maintain the tack in a lasting manner. To this end, at least one constituent of the adhesive is partly crosslinked and the partly crosslinked constituent is the product of partial crosslinking of at least one monomer containing double bonds, the monomer containing double bonds being a partial ester prepared by the reaction of an epoxy resin with an unsaturated carboxylic acid.
Full Text Semifinished Textile Product With at Least One Surface Provided With an
Adhesive
Description
The present invention relates to a semifinished textile product with at least one
surface provided with an adhesive according to the preamble of claim 1. It is known
to give self-adhesive properties to textiles used as reinforcing materials for the
production of fiber-reinforced components - so-called composites. In particular in the
automotive industry, boat construction or in the field of rotors for wind turbine
generators, where relatively large and complex preforms of dry reinforcing materials
are to be produced, there is an interest in fixing the individual textile layers. For this
purpose, usually, a so-called textile binder, for example a hot melt adhesive on the
basis of epoxy resins or polyamides or similar meltable strong resins, are applied on
the surface of the textiles. These self-adhesive textiles can then be placed in a mold
and held on the mold or on a layer already fixed thereon, by the adhesive.
Also, in the construction of sandwich components, there is often the need to ensure
the adhesion of textile layers on the core material used. This is usually balsa wood or
foams of polyvinylchloride (PVC), polyethylene (PE), polypropylene (PP),
polyurethane (PUR), polyethylene terephthalate (PET), polymethacrylimide
(Rohacell®).
A drawback of the hot melt adhesives hitherto used is that they are not tacky in
ambient temperature and therefore have to be heated for activation, or that with
adhesives that are sufficiently tacky at room temperature, the tackiness of the textiles
is reduced after just a short period of time, so that the textile cannot be stored over a
longer period of time without losing tackiness. This is due to the affinity of such melt
adhesives with respect to the coating of the fibers used, in particular if they are
formulated on the basis of epoxy resin, and to the capillary effect of the filaments.
These effects cause that the adhesive applied to the surface of the reinforcing
material migrates into the interior of the textile after a short period of time. Other
textile binders applied in powder form are not tacky at room temperature, but must be
superficially melted in order to achieve fixing of the layers.
Furthermore, it is known to apply styrene-dissolvable rubber or rubber emulsions on
the textiles to make their surfaces tacky.
Since rubber can only be dissolved with difficulty in the matrix resins used for
composite production, rubber remains a foreign material within the fiber-reinforced
component.
The consequences are bad surface quality of the fiber composite components, and a
non-tolerable reduction of the mechanical strength values of the components by
more than 25%.
The present invention is therefore based on the object to suggest a semifinished
textile product with a tacky surface, which can be stored over longer periods of time
and that has, if possible, no deleterious influence on the strength of the fiber
composite components made thereof, in spite of its tackiness.
According to the present invention, the object is achieved by the characterizing
features of claim 1. Advantageous embodiments are defined in the dependent
claims.
By partially crosslinking at least one constituent of the adhesive subsequent to the
application of the adhesive on the semifinished textile product, the adhesive is
immobilized. By immobilizing the adhesive on the surface of the semifinished textile
product, further entering and/or soaking of the adhesive into the semifinished textile
product can be avoided so that the adhesive is almost completely present on the
surface even after long periods of storage time.
The partially crosslinked constituent of the adhesive is the product of a partial
crosslinking of at least one monomer containing double bonds, wherein the partial
crosslinking is initiated by a well dosed application of energy on the surface of the
semifinished product, so that the partial crosslinking can take place after application
of the adhesive on the semifinished product.
A partial ester produced by converting an epoxy resin with an unsaturated carboxylic
acid is used as the monomer containing double bonds. This has the advantage that
an intermolecular link of the network resulting from the polymerization of the double
bonds with the network resulting from a later crosslinking of existing epoxy groups
(so-called interpenetrating networks) is enabled.
To produce the partial esters, preferably bisphenol A , bisphenol F epoxy resins
and/or particularly preferably epoxidized novolaks are used. The unsaturated
carboxylic acid can be selected from C1 to C12 carboxylic acids, wherein the use of
acrylic and methacrylic acids is particularly preferred, because they are available in
sufficient quantities as cheap standard chemicals and have a suitable reactivity with
respect to the epoxy group.
The partial ester is advantageously made by means of an incomplete conversion of
an epoxy resin with acrylic acid or methacrylic acid, wherein the incomplete reaction
is controllable by the stoichiometry of the starting materials. This reaction is
described in Publication of German Patent Application DE 10223313 A1,
incorporated in its entirety herein by reference.
The adhesive preferably further includes at least the following further constituents: an
epoxy resin, a rubber component and an initiator.
A preferred composition of the adhesive contains, with reference to the weight of the
entire mixture, about 25 - 40% rubber, 5 - 10% epoxy resin and 40 - 60% partial
ester. Moreover, the adhesive formulation includes a suitable initiator in the usual
concentration from 0.2 - 3% (particularly preferably 1 - 2%). Furthermore, the
adhesive can include the usual additives, such as pigments, processing aids or
additives to improve wetting of surfaces.
Particularly preferably the initiator is a photoinitiator able to be activated by UV light,
or a peroxide, because this enables the extent of the chemical partial crosslinking of
the adhesive to be controllable.
An epoxy resin according to the prior art can be used for the semifinished textile
product according to the present invention, wherein it is advantageous if the epoxy
resin is a bisphenol A resin, a bisphenol F resin, tetraglycidyl methylene dianiline
(TGMDA), triglycidyl paraaminophenol (TGPAP) and/or an epoxidized novolak. The
advantages of these epoxy resins are that they are compatible with the other
components of the adhesive, have excellent mechanical properties and ensure good
tackiness.
Furthermore, at least one rubber component, which can be a synthetic or natural
rubber, is necessary for the semifinished textile product according to the present
invention. Particularly suitable is amine and/or carboxy-terminated butadiene-nitrile
rubber (Hycar CTBN or ATBN) with a mean molecular weight of 2000 to 6000
g/mole, preferably mixed with NBR having a molecular weight of 20000 g/mole to
2000000 g/mole, particularly preferably 50000 g/mole to 1000000 g/mole, because it
has optimum tackiness and good compatibility with epoxy resins. By the prior
conversion of the rubber component with epoxy resins, also referred to as adducting,
the product properties can be additionally optimized. Carboxy-functionalized
butadiene rubbers with a molecular weight of 2000 to 10000 g/mole, which can be
produced, for example, by converting the homopolymerisates with maleic anhydride,
are also suitable.
Particularly advantageously the adhesive used for the production of the semifinished
product according to the present invention is capable of swelling and/or capable of
partial solution in reaction resin mixtures containing epoxy resins, because this
results in particularly close mixing of the adhesive with the resin matrix. This is
essential for the resulting mechanical strength of the component made thereof.
As the textile base for the manufacture of the semifinished textile product according
to the present invention, advantageously layers of fibers, woven, knitted and/or non-
woven fabrics are used alone or in combination. These reinforcing materials can be
of glass, carbon, aramid, natural fibers, such as flax, hemp, sisal or basalt fibers.
Other textile materials and constructions known from the prior art are also possible.
The application of the adhesive on the textile base is preferably by means of sprayin
a solution or melt of the adhesive, wherein an amount of 2 to 50 g/m2, particularly
preferably 4 to 15 g/m2, are applied to achieve optimum adhesive tackiness.
The semifinished textile products according to the present invention can be
preferably used for the production of fiber-reinforced plastic materials, wherein the
reaction resin used herein preferably includes an epoxy resin, or is an epoxy resin.
The particular advantage of the adhesive according to the present invention is the
chemical reaction of the epoxy groups contained in the adhesive with the epoxy
group of the reaction resin used and the resulting advantageous strength properties
of the fiber composite component.
The semifinished textile products according to the present invention have stable
surface tackiness over a period of more than 4 months up to several years. Even at
temperatures of about 60°C, good tackiness is maintained for a period of several
weeks to months.
Moreover, the semifinished textile products according to the present invention have
the advantage that textile reinforcement layers can be excellently positioned in a
component mold and repositioned multiple times as needed, and thus enable the
manufacture of complex three-dimensional preform geometries. The semifinished
textile products according to the present invention are particularly suitable for the
production of fiber-reinforced components in vacuum infusion and resin injection
processes (such as in resin infusion, resin transfer molding etc).
Furthermore, the semifinished textile products according to the present invention
have the advantage that the adhesive used does not significantly affect the
mechanical strength values of the fiber-reinforced component.
The properties achieved enable the semifinished textile products according to the
present invention to be used for the manufacture of lightweight structures in the field
of automotive engineering, aerospace, boat and ship building, sports articles and
rotor blades for wind turbine generators.
The invention will be explained in more detail in the following with reference to two
exemplary embodiments and three comparative examples:
Example 1
Composition of the adhesive:
- 270g of a conversion product of Hycar CTBN 1300 x 13 (Noveon) with EPR
0164(Bakelite AG)
- 80g EPR 0164 (Bakelite AG)
- 200g EPR 05322 (Bakelite AG)
- 439g EPA 03582 (Bakelite AG)
- 15g Genocoure MBF (Rahn AG)
- 15Cab-O-SilTS720
To produce the semifinished textile product according to the present invention, the
adhesive is preheated to a suitable temperature and sprayed on to the textile. It is
also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply
it to the textile in question without previous heating. By coating a unidirectional layer
of glass fibers (E-Glas; 2400 tex) with a weft percentage of 3% in the 90° direction
(E-Glas; 68 tex) with 10+/-2 g/m2 of the above-mentioned adhesive and partial
crosslinking by means of UV irradiation, the textile is given sufficient and durable
tackiness for more than four weeks without having to suffer any noticeable reduction
in the mechanical properties. Moreover, temperature resistance at 60°C is achieved.
Comparison of mechanical characteristics with and without the provision of adhesive:
GFK sample body: 8 layers of UD with about 1190 g/m2 weight per unit area
Sample thickness 6.1 mm; FHG 61 vol%
Resin system Hexion RIM135/RIMH137
Samples with adhesive according to example 1 unilaterally coated with about 10 g/m2

To produce the semifinished textile product according to the present invention, the
adhesive is preheated to a suitable temperature and sprayed on to the textile. It is
also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply
it to the textile in question without previous heating. By coating a unidirectional layer
of glass fibers (E-Glas; 2400 tex) with a weft percentage of 3% in the 90° direction
(E-Glas; 68 tex) with 10+/-2 g/m2 of the above-mentioned adhesive and partial
crosslinking by means of thermal activation for about 30 minutes at about 90°C, the
textile is given sufficient and durable tackiness for more than four weeks without
having to suffer any noticeable reduction in the mechanical properties. Moreover,
temperature resistance at 60°C is achieved.
Comparative example A
Composition of the adhesive:
- 2 weight% EPR 5311 (Bakelite AG)
- 86 weight% EPR 5322 (Bakelite AG)
- 12 weight% Hycar CTBN 1300 x 13 (Noveon)
To produce the semifinished textile product according to the present invention, the
adhesive is preheated to a suitable temperature and sprayed on to the textile. It is
also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply
it to the textile in question without previous heating. A unidirectional layer of glass
fibers (E-Glas; 2400 tex) with a weft percentage of 3% in the 90° direction (E-Glas;
68 tex) is coated with 10+/-2 g/m2 of the above-mentioned adhesive. The resulting
semifinished textile product shows high initial tackiness. However, the adhesive sinks
into the layer of fibers within less than five days. Moreover, temperature resistance at
60°C is not achieved.
Comparative example B:
Composition of the adhesive:
- 2 weight%BYK410(BYK)
- 65 weight% EPR 5322 (Bakelite AG)
- 33 weight% Hycar CTBN 1300 x 13 (Noveon)
To produce the semifinished textile product according to the present invention, the
adhesive is preheated to a suitable temperature and sprayed on to the textile. It is
also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply
it to the textile in question without previous heating. A unidirectional layer of glass
fibers (E-Glas; 2400 tex) with a weft percentage of 3% in the 90° direction (E-Glas;
68 tex) is coated with 10+/-2 g/m2 of the above-mentioned adhesive. The resulting
semifinished textile product shows high initial tackiness. However, the adhesive sinks
into the layer of fibers within less than five days. Sinking-in was already observed
after one day. Moreover, a temperature resistance at 60°C is not achieved.
Comparative example C:
Composition of the adhesive:
- 0.5 weight% EPR 5311 (Bakelite AG)
- 79.25 weight% EPR 5322 (Bakelite AG)
- 16.25 weight% Hycar CTBN 1300 x 13 (Noveon)
- 2 weight%BYK410(BYK)
- 2 weight% Aerosil A380 (Degussa)
To produce the semifinished textile product according to the present invention, the
adhesive is preheated to a suitable temperature and sprayed on to the textile. It is
also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply
it to the textile in question without previous heating. A unidirectional layer of glass
fibers (E-Glas; 2400 tex) with a weft percentage of 3% in the 90° direction (E-Glas;
68 tex) is coated with 10+/-2 g/m2 of the above-mentioned adhesive. The resulting
semifinished textile product shows high initial tackiness. However, the adhesive sinks
into the layer of fibers within less than fourteen days. Moreover, temperature
resistance at 60°C is not achieved.
Claims
1. A semifinished textile product with at least one surface provided with an
adhesive, wherein at least one constituent of the adhesive is partially crosslinked
and the partially crosslinked constituent is the product of partial crosslinking of at
least one monomer containing double bonds, characterized in that the
monomer containing double bonds is a partial ester prepared by the reaction of
an epoxy resin with an unsaturated carboxylic acid.
2. The semifinished textile product according to claim 1, characterized in that the
partial ester is the product of conversion of an epoxy resin with acrylic acid or
methacrylic acid in the stoichiometric ground weft.
3. The semifinished textile product according to claim 1 or 2, characterized in that
the partial ester is an epoxidized novolak.
4. The semifinished textile product according to at least one of the preceding
claims, characterized in that the adhesive further contains at least the following
further constituents: at least one epoxy resin, at least one rubber component and
at least one initiator.
5. The semifinished textile product according to at least one of the preceding
claims, characterized in that the initiator is a photoinitiator or a peroxide.
6. The semifinished textile product according to at least one of the preceding
claims, characterized in that the partial crosslinking of the partially crosslinked
constituents of the adhesive occurs on the surface of the semifinished textile
product by irradiating the semifinished textile product with UV radiation.
7. The semifinished textile product according to at least one of the preceding
claims, characterized in that the epoxy resin is a bisphenol A resin, a bisphenol
F resin, tetraglycidyl methylene dianiline (TGMDA), triglycidyl paraaminophenol
(TGPAP) and/or an epoxidized novolak.
8. The semifinished textile product according to at least one of the preceding
claims, characterized in that the rubber component is a synthetic or a natural
rubber.
9. The semifinished textile product according to at least one of the preceding
claims, characterized in that the adhesive is capable of being swelled and/or
partially dissolved in reaction resin mixtures containing epoxy resins.
10. The semifinished textile product according to at least one of the preceding
claims, characterized in that the semifinished product is a layer or layers of
fibers, a woven, knitted or non-woven fabric.
11. The semifinished textile product according to at least one of the preceding
claims, characterized in that the textile consists of glass, carbon, basalt, natural
fibers, such as flax, hemp, sisal and/or aramid fibers.
12. Use of a semifinished textile product according to any one of claims 1 to 11 for
the production of fiber-reinforced plastic materials.
13. Use of a semifinished textile product according to claim 12, characterized in
that a fiber-reinforced plastic is produced that includes at least an epoxy resin.
14. Use of a semifinished textile product according to any one of claims 1 to 11 for
the production of light-weight structures in the automotive or aerospace
industries, in boat and ship building, in sports articles, and in rotor blades for
wind turbine generators.

The present invention relates to a textile semifinished product with at least one surface provided with an adhesive,
wherein the adhesive is immobilized on the surface of the semifinished product in order to maintain the tack in a lasting manner. To
this end, at least one constituent of the adhesive is partly crosslinked and the partly crosslinked constituent is the product of partial
crosslinking of at least one monomer containing double bonds, the monomer containing double bonds being a partial ester prepared
by the reaction of an epoxy resin with an unsaturated carboxylic acid.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=X3PpIiMtDInON/dH/rHn9A==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 278076
Indian Patent Application Number 2277/KOLNP/2010
PG Journal Number 52/2016
Publication Date 16-Dec-2016
Grant Date 13-Dec-2016
Date of Filing 22-Jun-2010
Name of Patentee SAERTEX GMBH & CO. KG
Applicant Address BROCHTERBECKER DAMM 52, 48369 SAERBECK GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 PALINSKY, ANDREAS WIELANDSTRASSE 17, 47445 MOERS GERMANY
2 ISCHTSCHUK, LARS FRIEDENSHÖHE 34, 49205 HASBERGEN GERMANY
3 ROTH, EKKEHARD ROSTOCKER WEG 17, 21423 WINSEN GERMANY
PCT International Classification Number C09J 4/00
PCT International Application Number PCT/EP2009/050173
PCT International Filing date 2009-01-08
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2008 004 112.2 2008-01-11 Germany