HK1149579A - Textile semifinished product with at least one surface provided with an adhesive - Google Patents

Description

Textile semi-finished product having at least one surface provided with an adhesive

The invention relates to a textile semifinished product (textile halbzeug) having at least one surface provided with an adhesive, according to the preamble of claim 1.

It is known for textiles used as reinforcements in the production of fibre-reinforced components (so-called composites) to be provided with self-adhesive properties. There is an interest in the fixing of single-layer textiles, in particular in the field of rotors (rotors) of the automotive industry, of shipbuilding or of wind power stations, for the production of large and complex preforms (preforms) from dry reinforcing materials. For this purpose, so-called textile adhesives, for example hot-melt adhesives based on epoxy resins or polyamides or similar meltable solid resins, are usually applied to the surface of the textile. The self-adhesive textile can then be placed in a mould and held on the mould or on a layer already fixed to the mould by means of an adhesive.

The production of sandwich elements (sandwichbauteie) generally requires that the textile layer is adhered to the core material used. The core material is typically balsa wood (Basalwood) or polyvinyl chloride (PVC) foam, Polyethylene (PE) foam, polypropylene (PP) foam, Polyurethane (PUR) foam, polyethylene terephthalate (PET) foam, polymethacrylimide (Rohacell)) And (3) foaming.

The disadvantages of the hot-melt adhesives used up to now are as follows: the hot melt adhesive is either non-tacky at ambient temperature and must therefore be heated to activate; or for adhesives that are sufficiently tacky at room temperature, the tackiness of the textile decreases only after a short time, so that the textile cannot be stored for a longer period of time without losing tackiness. This is due to the affinity of the hot melt adhesive for the coating (binder) of the fibers used, in particular when the hot melt adhesive is formulated on the basis of epoxy resins, and also due to the capillary effect of the filaments. This effect allows the adhesive applied to the surface of the reinforcement to migrate into the interior of the textile after a short period of time. Other textile adhesives applied in powder form are not tacky at room temperature and must be melted under the influence of temperature to achieve layer fixing.

It is also known to apply styrene-soluble rubber or rubber emulsions to textiles to impart tackiness to the surface of the textile.

Since the rubber is difficult to dissolve in the resin matrix used for the production of the composite material, the rubber is present in the form of inclusions in the fibre-reinforced component. The result is a fiber composite component with a poor surface quality and an insignificant reduction in the mechanical strength values of the component of more than 25%.

It is therefore an object of the present invention to provide textile semiproducts having an adhesive surface, which can be stored for a long time and which, despite their adhesive properties, have as little negative effect as possible on the strength of the fibre composite component produced therefrom.

According to the invention, this object is achieved by the features of claim 1. Advantageous embodiments are given in the dependent claims.

After the adhesive has been applied to the textile semifinished product, the adhesive is fixed by partially crosslinking at least one component of the adhesive. By fixing the adhesive to the surface of the textile semifinished product, further penetration and/or penetration of the adhesive into the textile semifinished product can be avoided, so that the adhesive remains almost completely on the surface even after prolonged storage.

The partially crosslinking constituent of the adhesive is the product of partial crosslinking of at least one monomer containing double bonds, the partial crosslinking being initiated by applying a specific energy to the surface of the semifinished product, so that the partial crosslinking can take place after the adhesive has been applied to the semifinished product.

As monomers containing double bonds, use is made of partial esters (Partialester) prepared by reaction of epoxy resins and unsaturated carboxylic acids. This has the advantage that intramolecular links can be formed between the network formed by the polymerization of the double bonds and the network formed by subsequent crosslinking of the epoxy groups present (so-called interpenetrating networks).

For the preparation of the partial esters, preference is given to using bisphenol A epoxy resins, bisphenol F epoxy resins and/or particular preference to using epoxidized phenolic novolac resins (Novolak). The unsaturated carboxylic acid may be selected from C1-C12 carboxylic acids, of which acrylic acid and methacrylic acid are particularly preferred because they can be supplied in sufficient amounts and inexpensively as standard chemicals and they exhibit suitable reactivity towards epoxy groups.

The partial esters are advantageously prepared by incomplete reaction of the epoxy resin and acrylic acid or methacrylic acid, the incomplete reaction being controllable by the stoichiometry of the starting materials. This reaction is described in the publication DE 10223313A 1, the content of which is hereby fully incorporated into the disclosure of the present patent application by reference.

The adhesive preferably further comprises at least the following additional components: epoxy resin, rubber component and initiator.

Preferred components of the adhesive comprise: 25-40% of rubber, 5-10% of epoxy resin and 40-60% of partial ester based on the weight of the whole mixture. In addition, the adhesive formulation contains a suitable initiator, the concentration of which is generally 0.2 to 3% (particularly preferably 1 to 2%). In addition, the adhesive may contain customary additives, for example pigments, processing aids or additives for improving the wetting of surfaces.

It is particularly preferred that the initiator is a photoinitiator or peroxide which can be activated by UV light, since it is thereby possible to achieve a controlled crosslinking of the chemical moieties of the adhesive within certain limits.

Epoxy resins according to the prior art can be used for the textile intermediate according to the invention, wherein advantageous epoxy resins are bisphenol a resins, bisphenol F resins, tetraglycidyl diphenylaminomethane (TGMDA), triglycidyl para-aminophenol (TGPAP) and/or epoxidized novolac resins. The advantage of these epoxy resins is that they are compatible with the other components of the adhesive, have very good mechanical properties and ensure good adhesion.

Furthermore, the textile semi-finished product according to the invention requires at least one rubber component, which may be synthetic rubber or natural rubber. Particularly suitable are amino-and/or carboxyl-terminated nitrile rubbers (Hycar CTBN or ATBN) having an average molecular weight of 2000 to 6000g/mol, preferably mixed with NBR having a molecular weight of 20000 to 2000000g/mol, particularly preferably 50000 to 1000000g/mol, since NBR has the best viscosity and good compatibility with epoxy resins. By the aforementioned reaction (also referred to as addition) of the rubber component and the epoxy resin, the properties of the product can additionally be optimized. Furthermore, suitable are carboxyl-functionalized butadiene rubbers having a molecular weight of 2000 to 10000g/mol, which can be prepared, for example, by homopolymerization of maleic anhydride.

It is particularly advantageous if the adhesive used for producing the textile semifinished products according to the invention is expandable (quellbar) and/or partially soluble in the reaction resin mixture containing the epoxy resinSince in particular a thorough mixing of the adhesive and the resin matrix is thereby achieved. This is of great importance for the final mechanical strength of the component produced therefrom.

As textile substrates for the production of the textile semi-finished products according to the invention, use is advantageously made of layered fibers (Gelege), woven fabrics (Gewebe), knitted fabrics (Gewirke), knitted fabrics (Gestick) and/or nonwoven fabrics (Vlies), alone or in combination. These reinforcements may be prepared from glass fibers, carbon fibers, aramid fibers, natural fibers (such as flax, hemp, sisal) or basalt fibers. Other textile materials and structures known in the art may be used.

The adhesive is preferably applied to the textile substrate by spraying a solution or melt of the adhesive, wherein the coating amount is 2 to 50g/m²Particularly preferably 4 to 15g/m²To achieve optimum adhesion.

The textile semifinished products according to the invention can preferably be used for producing fiber-reinforced plastics (Kunststoff), wherein the reaction resins used here preferably contain epoxy resins or are epoxy resins. The particular advantage of the adhesive according to the invention lies in the chemical reaction of the epoxide groups contained in the adhesive and of the epoxide groups of the reaction resin used, and in the advantageous strength properties of the fiber composite component obtained from this reaction.

The textile intermediate according to the invention has a stable surface tack at room temperature over a period of more than 4 months to several years. Good tack is maintained for weeks to months even at temperatures of about 60 ℃.

Furthermore, the textile intermediate product according to the invention has the following advantages: the textile reinforcement layer can be excellently positioned in the component mould and can be repositioned as many times as necessary, so that a preform of three-dimensional geometrically complex shape can be produced. The textile semifinished product according to the invention is particularly suitable for producing fibre-reinforced components in vacuum infusion processes and resin injection processes (for example resin infusion, resin transfer moulding, etc.).

Furthermore, the textile intermediate product according to the invention has the following advantages: the adhesive used does not significantly affect the mechanical strength values of the fiber-reinforced component.

The properties achieved make it possible to use the textile semifinished products according to the invention in the automotive sector, in the aeronautical industry, in ship building (Boots-und Schiffbau), in sports goods and in rotor blades for wind power plantsLightweight structures are produced in the field.

The present invention will be described in detail below using two exemplary examples and three comparative examples.

Example 1

The adhesive comprises the following components:

270g of the reaction product of Hycar CTBN 1300X 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-Sil TS 720

To produce the textile semifinished product according to the invention, the adhesive is preheated to a suitable temperature and sprayed onto the textile. It is also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply the adhesive to the textile concerned without preheating. By using 10+/-2g/m²The above-mentioned adhesive of (1) was coated with unidirectional layered fibers (Gelege) consisting of glass fibers (alkali-free glass (E-Glas); 2400 tex) and containing 3% of weft threads (alkali-free glass; 68 tex) in the 90 deg. direction and partially cross-linked by UV radiation, thus giving the textile a sufficient and durable tack for more than 4 weeks without any appreciable reduction in the mechanical properties of the textile. In addition, heat resistance at 60 ℃ was achieved.

Comparison of mechanical parameters with and without adhesive:

GFK sample: 8 layers of UD, having a density of about 1190g/m²Weight per unit area of

Thickness of the sample: 6.1 mm; FHG 61% by volume

Resin system: hexion RIM135/RIMH137

The sample with adhesive according to example 1 was coated on one side with about 10g/m²

Three-point bending test to DIN EN ISO 14125

The test direction is as follows: 0 degree

Punch radius R1: 5mm

Seat radius R2: 5mm

Testing speed: 2 mm/min

And (3) testing results: elastic modulus [ GPa ] Rm [ MPa ]

Sample body

48940 without adhesive

With adhesive 46920

Example 2

The adhesive comprises the following components:

-100g Hycar CTBN 1300×13(Noveon)

-20g Araldite GY 250(Huntsman)

-40g EPR 03161(Bakelite AG)

-220g EPA 04704(Bakelite AG)

-2% by weight MEKP

0.15% by weight of cocatalyst

To produce the textile semifinished product according to the invention, the adhesive is preheated to a suitable temperature and sprayed onto the textile. It is also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply the adhesive to the textile concerned without preheating. By using 10+/-2g/m²The above-described adhesive coats the unidirectional layered fibers and partially crosslinks by thermal activation at about 90 ℃ for about 30 minutes, thereby imparting sufficient and durable tack to the textile for greater than 4 weeks without being perceived asThe mechanical properties of the textile are reduced, the unidirectional layered fibers being composed of glass fibers (alkali-free glass; 2400 tex) and containing 3% of the weft threads (alkali-free glass; 68 tex) in the 90 ° direction. In addition, heat resistance at 60 ℃ was achieved.

Comparative example A

The adhesive comprises the following components:

2% by weight EPR 5311(Bakelite AG)

86% by weight EPR 5322(Bakelite AG)

12% by weight of Hycar CTBN 1300X 13(Noveon)

To produce the textile semifinished product according to the invention, the adhesive is preheated to a suitable temperature and sprayed onto the textile. It is also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply the adhesive to the textile concerned without preheating. With 10+/-2g/m²The above-mentioned adhesive of (1) coats unidirectional layered fibers composed of glass fibers (alkali-free glass; 2400 tex) and having 3% of weft in the 90 deg. direction (alkali-free glass; 68 tex). The textile half-products obtained exhibit a high initial tack. However, the adhesive penetrates into the layered fibers in less than 5 days. In addition, heat resistance at 60 ℃ was not achieved.

Comparative example B

The adhesive comprises the following components:

2% by weight BYK410(BYK)

65% by weight EPR 5322(Bakelite AG)

33% by weight of Hycar CTBN 1300X 13(Noveon)

To produce the textile semifinished product according to the invention, the adhesive is preheated to a suitable temperature and sprayed onto the textile. It is also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to coat the adhesive on the phase without preheatingAnd (3) a textile product. With 10+/-2g/m²The above-mentioned adhesive of (1) coats unidirectional layered fibers composed of glass fibers (alkali-free glass; 2400 tex) and having 3% of weft in the 90 deg. direction (alkali-free glass; 68 tex). The textile half-products obtained exhibit a high initial tack. However, the adhesive penetrated into the layered fibers (Gelege) in less than 5 days. After one day, infiltration was observed. In addition, heat resistance at 60 ℃ was not achieved.

Comparative example C

The adhesive comprises the following components:

0.5% by weight EPR 5311(Bakelite AG)

79.25% by weight EPR 5322(Bakelite AG)

16.25% by weight of Hycar CTBN 1300X 13(Noveon)

2% by weight BYK410(BYK)

2% by weight Aerosil A380(Degussa)

To produce the textile semifinished product according to the invention, the adhesive is preheated to a suitable temperature and sprayed onto the textile. It is also possible to dissolve the adhesive in acetone or methyl ethyl ketone and to apply the adhesive to the textile concerned without preheating. With 10+/-2g/m²The above-mentioned adhesive of (1) coats unidirectional layered fibers composed of glass fibers (alkali-free glass; 2400 tex) and having 3% of weft in the 90 deg. direction (alkali-free glass; 68 tex). The textile half-products obtained exhibit a high initial tack. However, the adhesive penetrated into the layered fibers in less than 14 days. In addition, heat resistance at 60 ℃ was not achieved.

Claims (14)

1. Textile semifinished product having at least one surface provided with an adhesive, wherein at least one component of the adhesive is partially crosslinked and the partially crosslinked component is the product of partial crosslinking of at least one monomer containing a double bond, wherein the monomer containing a double bond is a partial ester prepared by reaction of an epoxy resin and an unsaturated carboxylic acid.

2. The textile intermediate product of claim 1, wherein the partial ester is a product of the reaction of an epoxy resin with acrylic acid or methacrylic acid in substoichiometric amounts.

3. The textile half-product of claim 1 or 2, wherein the partial ester is an epoxidized novolac resin.

4. The textile intermediate product of at least one of the preceding claims, wherein the adhesive further comprises at least the following further components: at least one epoxy resin, at least one rubber component, and at least one initiator.

5. The textile half-product of at least one of the preceding claims, wherein the initiator is a photoinitiator or a peroxide.

6. The textile half-product of at least one of the preceding claims, wherein the partial crosslinking of the partially crosslinked component of the adhesive on the surface of the textile half-product is carried out by irradiating the textile half-product with UV light.

7. The textile half-product according to at least one of the preceding claims, wherein the epoxy resin is a bisphenol a resin, a bisphenol F resin, tetraglycidyl diphenylaminomethane (TGMDA), triglycidyl para-aminophenol (TGPAP) and/or an epoxidized novolac resin.

8. The textile half-product of at least one of the preceding claims, wherein the rubber component is a synthetic rubber or a natural rubber.

9. Textile intermediate product according to at least one of the preceding claims, wherein the adhesive is swellable and/or partially soluble in a reaction resin mixture comprising an epoxy resin.

10. The textile half-product of at least one of the preceding claims, wherein the half-product is a layered fiber, a woven fabric, a knitted fabric and/or a nonwoven fabric.

11. The textile half-product of at least one of the preceding claims, wherein the textile is composed of glass fibers, carbon fibers, basalt fibers, natural fibers, such as flax, hemp, sisal, and/or aramid fibers.

12. Use of a textile half-product according to at least one of claims 1 to 11 for producing a fiber-reinforced plastic.

13. Use of a textile intermediate product according to claim 12 for the production of a fibre-reinforced plastic containing at least one epoxy resin.

14. Use of a textile half-product according to any of claims 1 to 11 for producing lightweight structures in the automotive sector, in the aeronautical industry, in shipbuilding, in sports goods and in rotor blades of wind power stations.