DE2552688C2 - Process for the production of laminates - Google Patents

Description

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The invention relates to a method for producing laminates from a synthetic resin impregnated Base layer and one or two synthetic resin-impregnated top layer (s) in the generic term of the claim 1 described Art.

In the manufacture of ski components, which the ski both as an upper chord and / or lower chord as well as Various methods are used to provide abrasion-resistant, decorative cover surfaces. One hand receives such components by gluing fiber-reinforced laminates with various thermoplastic films or decorative laminate panels, on the other hand, the fiber-reinforced laminate layer can be pre-impregnated State (B-state, prepreg) with also pre-impregnated non-reinforced base layers Resin-impregnated papers or fleeces are pressed and one obtains a composite material higher mechanical strength with a resin-rich, possibly decorative and abrasion-resistant surface. Similar Products are obtained by processing the laminates and resins mentioned in the wet pressing process.

All of these processes are labor intensive, require two or more impregnation processes, and Larger production series for reasons of rationality.

From DE-OS 20 24 778 a method for the production of decorated, shaped objects is known, in which an aminoplast resin compound with a decorative paper and an impregnated sheet at very high pressures is pressed, whereby about dinner plates are produced. Such aminoplast resins are however, mainly due to their high brittleness, not for the production of ski components and laminates of the type in which they are to be produced according to the preamble of claim 1, suitable. ,

In DE-OS 25 08 518 a method of the type described above for the production of ski components is described, in which a resin-impregnated base layer and a resin-impregnated top layer are pressed together will. This process has the disadvantage that the base and top layers are carried out in separate operations need to be impregnated with resin.

The invention is based on the object of creating a method of the type described at the outset which can be carried out in a simplified manner compared to the known method and in which it is nevertheless ensured that the cover layers are uniformly free of bubbles and homogeneously with respect to the plastic. To achieve the object, the method according to the invention is designed in such a way that the resin of the base layer is selected within the limits of 40 to 70% by weight, based on the total weight of the base layer, so that the synthetic resin flows is achieved, which measured at a pressure of 5 kg / cm ² , 150 ° C and 10 minutes duration is at least 10%, and that the impregnation of the absorbent material of the top layer is made completely from the resin supply of the base layer after being placed on the base layer.

After that, a ski component with a decorative surface can be produced without the need for a base and Top layer must be impregnated separately. This is done by putting on a pre-hardened, resin impregnated Base layer a top layer is pressed, which is not itself impregnated with synthetic resin, but during the pressing process from the base layer absorbs so much of the re-liquefied resin that it not only sticks to the bottom layer, but is completely soaked with resin, so that a smooth Resin surface is created that does not have to be reworked.

Fabrics, fleece or other fiber products are impregnated with enough synthetic resin, namely 40 to 70% by weight, based on the total weight of the base layer, that there is enough resin for the cover layers to be applied when the combination is pressed to completely soak and cover these cover layers . Typically, 30 to 40 percent by weight resin, based on the total weight of the base layer, is sufficient to produce the laminate. The amount of resin applied depends on the "flow" of the respective resin. This "flow" must be at least 10% under compression conditions of 5 kg / cm ² at 150 ° C. and 10 minutes in order to achieve the effect according to the invention.

The choice of the ratio of resin to reinforcing fiber material in the prepreg serving as the base layer within the limits according to the invention is intended to ensure that enough liquid resin is available under the conditions of the compression to completely penetrate the cover layers and thus a perfect resin layer on the surface guarantee. Of course, it must be taken into account how thick the top layer to be impregnated should be. As a rule, a thinner top layer will require a lower resin concentration in the base layer than must be used if the top layer is stronger. Of course, the flowability of the resin of the base layer also plays a role here, so that, even if there is sufficient resin in the base layer, it must be ensured that the flow reaches a value which ensures perfect impregnation of the top layer. Here, too, the flow will have to be chosen higher with increasing thickness of the top layer, so that, for. B. a flow of the minimum limit of 10% with an edition of 70-80 g / cm ^{2 is} completely sufficient,

while with a larger edition ζ. B. over 100 or even 150 g / cm ^{2 is} appropriate to work with a higher flow.

By using decorative strips made of paper, fleece or similar materials or from Colored resins and non-colored sheets for the top layer can have any surface effects be achieved. The use of absorbent materials, readily flowable resins and / or suitable Pressing conditions are a prerequisite for a perfect success of the process.

The base layer consists mainly of glass fibers, but these can also be wholly or partially through Carbon fibers are replaced with the construction the base layer can be a woven, knitted fabric, fleece or the like. As a top layer are above all Paper, absorbent nonwovens made of cellulose, cotton or glass as well as mixed nonwovens should be mentioned.

The advantage of the method according to the invention is that only one impregnation process is required and that the end product is homogeneous with respect to the plastic.

The following examples are intended to explain the process in more detail.

example 1

As a base or base layer, a unidirectional glass ^{silk fabric of 500 g / m 2 is} impregnated with about 50% by weight of an epoxy resin of the diglycidyl ether of bisphenol A type with an amine hardener which is adjusted to a flow of 10% (prepreg) and 5 kg / cm ² compressed together with an absorbent, colored alpha-cellulose paper of 80 g / m ² at about 150 ⁰ C and. The laminate removed from the press after recooling consists of an approx. 0.4 mm thick GRP layer and an approx. 0.1 mm thick cover layer.

Example 2
As a base or base layer, 2 layers of glass silk fabric are impregnated with approx. 45% by weight resin, which is adjusted to 20% flow, and with a layer of absorbent 160 g / m ² paper at 130 ° C, as in Example 1, 12 kg / cm ² and pressed for 30 minutes. - The result is a laminate with an approx. 0.8 mm thick GRP layer and a 0.15 mm thick top layer

Example 3

A layer is used as a base or base layer

κ, glass silk fabric as in Example 1 with 55% by weight resin, which is adjusted to a flow of 15%, impregnated and ^{placed on both sides with a layer of 80 g / m 2} decorative paper, pressed. 4 mm thick

ι j GRP layer and two approx. 0.1 mm thick on both sides Top layers.

Example 4

The procedure is as in Example 1, but the epoxy resin is colored and the GRP prepreg is ^{pressed with a 100 g / m 2} cellulose fleece, cotton fleece, cellulose-cotton mixed fleece or glass fleece.

The result is a laminate with an approx. 0.4 mm thick GRP base layer and an approx. 0.2 mm thick, in the Color of the epoxy resin colored top layer.

Example 5

The procedure is as in Example 1, but with the warp threads through completely or partially in the glass fabric Carbon fiber threads are replaced.

Example 6

The procedure is as in Example 1, but an unsaturated polyester with diallyl phthalate as the synthetic resin used as a crosslinker and di-t-butyl peroxide as a hardener. The flow of the prepreg is at the Impregnation set to 15%, which ensures complete impregnation of the top layer is.

Claims (1)

Claim: Process for the production of laminates, consisting of fiber reinforcements, such as fabrics made of glass fibers, carbon fibers or mixed fabrics of these fibers with other fibers, having a base layer and at least one cover layer based on absorbent material, both an epoxy resin or unsaturated polyester resin, which can be modified by diallyl phthalate , in which it is assumed that the resin-containing base layer material is present in precured form, the absorbent material of the cover layer is impregnated with resin and both layers are bonded together under pressure and curing of the synthetic resin, characterized in that the resin of the base layer within the limits of 4ΰ to 70% by weight, based on the total weight of the base layer, is chosen so that a flow of the synthetic resin is achieved which is measured at a pressure of 5 kg / cm ² , 150 ° C and 10 minutes duration at least 10%, and that the impregnation of the suction Capable material of the top layer is made completely from the resin supply of the base layer after it has been placed on the base layer. ₁₀