MXPA98002301A - Configured elements united with thermo-dependable resins - Google Patents

Abstract

Fibrous shaped elements bonded with thermosetting resins comprising a plurality of fiber layers with at least two cohesion agents bonded with thermosetting resins, preferably with inner fiber layers comprising phenolic resins such as the cohesion agent and the upper and lower outer layers which comprise epoxy resins as cohesive agents

Description

* ELEMENTS CONFIED UNITED WITH TERMOENDO ECIBLE RESINS STATE OF THE ART Parts configured produced from fibers, such as those used in the manufacture of automobiles 5 as parts to regulate the climate and to absorb the sounds and parts configured with a high Surface resistance and fractures are conventionally produced by compression molding and simultaneous curing of fiber layers bound with phenolic resin (shaped fabrics). These products have the disadvantage that eventually, especially when exposed to the effects of high temperatures and humidity, they produce an unpleasant smell due largely to the curing agent (hexameth and lens) and their decomposition products. of amine. Ds according to EP-A 0 254,807. This problem is solved by the use of a mixture in powder form as a cohesion agent comprising a phenolic resin which is not thermoreactive and one or more products of condensation of the group of phenolic resins, amine resins or epoxy resins. Even when the odor formation caused by the hemetramine and the lens can be reduced in this way, a residual odor remains due to the phenolic resin. OBJECTS OF THE INVENTION • It is an object of the invention to provide fibrous elements configured with a thermosetting resin as a cohesion agent that maintains good metallic properties, sound absorption and resistance to combustion of the fibrous shaped elements bonded with resin It is another object of the present invention to provide a method for producing shaped fibrous elements which can be used for the production of phenol resins without the odor development of phenol resins. have an increased resistance with a reduction in weight of the automotive vehicle components without any loss of quality. These and other objects and advantages of the present invention will be apparent from the following description detailed of the invention. THE INVENTION The fibrous shaped elements of the present invention are formed of at least two layers of fibers using resin cohesion agents of termaendur-ec ient different. Preferably, the shaped elements are formed of at least one inner fiber layer with a phenolic resin cohesion agent and at least one topcoat fiber layer and a lower reverse fiber layer bonded with a resin agent. epó ica.

The thermosetting resin cohesion agents may be self-healing resins or they may be provided with a curing or curing-curing agent which are cured to form a polymer product higher than a high specific temperature. Examples of suitable thermosetting resins are diallyl phthalate resins, epoxy resins, urea resins, melamine resins, non-melamine resins, non-phenolic melam resins, phenolic resins, and metalliferous resins. 10 same. Preferred resins are based on phenolic resins and epoxy resins. It is surprising that the fibrous shaped elements produced by the invention do not develop odor of the degradation products of phenol resin or amine In addition, all fibrous shaped elements are permeable to air and gases, even if the fiber layers joined by thermosetting resin are indistinct, and consequently also all fibrous shaped elements are permeable to air and gases. It is an additional unexpected benefit of these configured elements Fibers having an increased strength ds such that it is possible to achieve the same strength with thinner fibrous shaped elements of the present invention as compared to what can be achieved with heavy, conventional, fibrous shaped elements. bound only with a phenol resin. In particular, a further increase in strength and a decrease in odor emissions is achieved and the fiber layers provided with the thermosetting resin cohesion agents are produced in accordance with a carding process. Examples of the phenolic cohesion agents are all condensation products of phenols and aldehydes, especially phenol, cresol or xylene with an ideal form, most preferably resoles and novolac conventions, with highest preference mixtures of novolac and hexamethyl etramine. Usually, phenolic resins are used in the form of polyes. Cohesion agents based on epoxy resins are usually a mixture of epoxy compound dust with at least two epoxy groups per molecule and one agent of _? healing. Latent curing agents are preferred to obtain a sufficient processing time between the mixing time and the cure time. Examples of latent curing agents are acid anhydrides or imidazole derivatives but novslac or complex metal compounds are preferred as described in EP-B 0,518,908. Examples of fibers are inorganic fibers such as for example glass fibers and inorganic fiber type materials or well mixed fiber. Preferably, they are organic fibers, for example wool, cotton, raw fibers, jute, linen, hemp, palisades or acrylic fibers. A large part of the material 1 of fiber can be extracted from waste materials by means of a recovery process in which the fibers are mixed by methods known per se with the cohesive cohesion agents and are placed in layers. discrete fibers (configured fabrics, paricularly shaped carded fabrics). According to the invention, several layers of fibers (fabrics of shaped fabrics) with at least two different thermosetting resin cohesion agents are placed one on top of the other. Preferably one or more fiber layers are used together with phenolic resin or linking agent as the inner layer and its upper side and its lower side are both equipped with a coating layer comprising one or more layers of fibers comprising resin Epoxy co or cohesion agent. The individual layers of fibers or the stacked structure (intermediates) are cut to size in a manner known per se and can either be pre-cured or subsequently cured while they are being configured, or the stacked structures are cured in an intermediate manner co-or sheets at temperatures higher than the curing temperatures of the thermosetting resin cohesion agents. In the simplest case, fibrous shaped fabrics are combined, in each case, with different cohesion agents as semi-finished products and are molded and cured at a temperature above the curing temperature of the cohesion agents of the thermosetting resin. Potentially while they are being configured. For example, a hat rack with a weight per unit area of 2500 g / m2 can be manufactured from two semi-finished products each weighing 500 g m2 with a mixture of epoxy resin curing agent as the cohesion agent and a semi-finished product interspersed with a weight of 15O0 g / m2 with no o'lac hexameth and lens or cohesive agent. The preferred method of the invention for the production of the bonded fiber layers of thermosetting resin is the carding process where the fibers are combed until very thin rows are obtained which are then provided with cohesion agents and are stacked in longitudinal and transverse position until reaching the desired weight per unit area with the upper cover layer, the layer average and layer below comprising different cohesive agents, if desired. The middle layers also preferably comprise phenolic resins and the upper and lower outer layers comprise epoxy resins as the cohesive agent. In a particularly preferred method, fabrics configured Fibers (fiber layers) are produced by means of the carding process in such a way that in the continuously produced fiber felt it is sprayed in the longitudinal direction in three broad equal zones or different cohesive agents so that the internal zone is expanded. it contains the cohesion agent for the inner layer of the fibrous shaped element and the two outer zones contain the cohesion agent (s) for the upper and lower outer layers of the fibrous shaped element. The configured fabric fabric produced from this The shape is arranged in a cross-crease technique. Thus, the newly configured fiber felt comprises layers of fiber with different cohesion agents. This shaped fiber felt is briefly heated in such a way that the resin cohesive agents of thermosetting melt and stick to the fiber, but do not heal. The configured fiber felt is then cooled and adjusted. Finally, the intermediate products produced in this way, while they are being configured, are molded and cured in a manner known per se. for this purpose and several of these semi-nominated products can also be placed one above the other and molded together and cured. In the following example, a preferred embodiment for illustrating the invention is described. However, it must be understood that the invention is not intended to be limited to the specific embodiment. EXAMPLE The phenol resin cohesion agent employed was a phenol novolac with a softening point of 98 * C 5 mixed with h by weight of hexameth and lens and the epoxy resin cohesion agent employed was a mixture of a resin. epoxy based on bisphenol A (equivalent of epoxides 183 ^ softening point-: 75 ° C) and 5% by weight of an agent * of latent healing comprising a "solid solution" in powder of 30 of 2 ~ met i 1-imidazole in 70 /. of a phenol novolac that has a high melting point. Using the carding process, a fibrous shaped fabric consisting of a mixture of textile fibers and powder resin cohesive agents was produced with inuamente.

Once the fiber felt was formed, the different cohesion agents were sprayed in the longitudinal direction in three zones of equal widths. The two outer zones received the epoxy resin binding agent and the inner zone received the phenol resin cohesion agent. He The shaped fiber felt produced in this way was arranged in a cross-bent technique known per se such that a new shaped fiber felt was formed wherein the inner layer comprised the phenolic resin and the upper and lower outer layer comprised the resin ep? ica as a liaison agent.

Said shaped fiber felt was carried in a speculative air oven maintained at a temperature of 15 * 0 at such a rate that the cohesion agents were fused and fixed in the fibers, but were not cured. The fabric was then cooled, which was adjusted and then, while configured, was molded for 60 seconds at a temperature comprised between 180 ~~90 ° C and under a pressure of 170 bar, and was cured. The fibrous shaped element bonded with thermosetting resin was self-resistant to flames and when exposed to external flames, exhibited a low smoke density. The fibrous configured element does not pressnt? odors, even under the effect of high temperatures (40-70 C) and high humidity (90 * relative humidity). In comparison with a fibrous shaped element joined only with fanic resins of the same weight per unit area, it showed a resistance that was increased by 27% and no separation phenomena of individual layers were observed, which is known as divi ions. Various modifications of the elements and methods of the invention can be carried out without departing from the spirit or scope of said invention and it will be understood that the invention is limited only in accordance with that defined in the appended claims.

Claims (9)

1. CLAIMS í. A fibrous shaped element comprising at least two fiber layers employing different thermosetting resin cohesion agents.
2. 2. A fibrous shaped element where one cohesion agent is a phenol resin and the other cohesion agent is an epoxy resin.
3. 3. A fibrous shaped element in accordance with the * rei i dication i which comprises the imanos a layer of fiber 10 internal with a phenol resin cohesion agent and at least one outer top and bottom layers with a cohesion agent.
4. 4. A fibrous shaped element according to claim 1 wherein the fiber layers are produced 15 by the carding procedure.
5. 5. A fibrous shaped element according to the indication 3 where the fiber layers are produced by the carding process.
6. 6. A process for the preparation of a fibrous shaped element of claim 1 comprising the combination of at least two layers of fiber impregnated with different cohesive agents of thermosetting resin and curing of the combined layers at a higher temperature. at the curing temperature of the thermosetting resins.
7. 7. A process for the preparation of a shaped fibrous element of claim 3 providing at least one "inner layer of fibers with a phenolic resin cationing agent with at least one top fiber layer 5 external and a layer of external lower fiber with an agent of cohesion of resin ep? ica and curing of the element at a temperature above the curing temperature of the cohesion agents- #
8. 8. The process according to claim 1, wherein the layers of the ss fibers produce by means of the carding method.
9. 9. A process for the preparation of fibrous shaped element of claim 1 comprising the formation of fiber layers by means of the carding process, the 15 spraying the fiber fabric into three longitudinal zones with the inner zone receiving a phenolic powder resin and the two outer zones receiving an epoxy resin m powder, using the fiber mat coated with cross-bent for the purpose of form a fiber fabric with a 20 inner fiber layer with a phenolic resin cohesion agent and an external upper and lower fiber layer with an epoxy binder, briefly warming the fiber felt configured to melt the cohesive agents without cure, cooling already using the fiber felt Y 25 by shaping, molding and curing the fiber felt.