DE1284083B - Process for the production of molded articles reinforced with glass fibers, synthetic or natural fibers - Google Patents

Description

Molded bodies, such as plates and the like, made of glass fiber reinforced synthetic resins have been known for a long time. In place of the fiberglass it has synthetic fibers are already being used for the same purposes. For the production Such moldings are based on fabrics or mats, which are initially mixed with unsaturated Polyesters, optionally together with other polymerizable organic compounds, such as styrene, methyl methacrylate, or impregnated or coated with polyepoxides. The curing of these shaped bodies can be carried out with the aid of catalysts of accelerators, by the action of temperature, by irradiation with ultraviolet Light. It is also possible to cure at room temperature, which is associated with certain advantages, such as efficient production. This kind of On the other hand, however, curing also entails considerable difficulties. this is the case in particular in the continuous production of the moldings and is due to the limited "pot life" of the catalyst and accelerator mixed mixture of the monomeric, polymerizable and the polymeric compound. Another difficulty here is the poor adhesion of the synthetic resin on the fibers. In order to avoid this as far as possible, it is known to use the glass fibers pre-treat in some way. For this purpose, copper oxide is applied on the fibers and the subsequent reduction to metallic copper as well as the Treatment with silanes or cationic adhesives in question.

- It has also become known that the glass fibers are better bonded to achieve with the synthetic resin that the polymerization of the glass surface lets go out. For this purpose, the peroxides are used as polymerization catalysts applied to the glass fibers while adding the accelerator to the resin. This made it possible to reduce the water absorption of the molded body produced and the water resistance can be increased. This method was disadvantageous an extension of the curing times, and the risk of undercuring also increased as a result of localization of the hardening in the vicinity of the glass fibers.

It has now been found that by glass fibers, synthetic or natural fibers reinforced moldings based on polyacrylic or poly- methacrylic acid esters by curing monomeric methacrylic acid esters by curing of monomeric acrylic or methaerylic acid esters, optionally in the presence of these esters sat in these dissolved polymers and, if appropriate, in their presence another monomeric polymerizable compound with the help of peroxidic Can produce catalysts and possibly other customary accelerators, if the reinforcing material is pretreated with a hydrochloride of an organic base, then applies the polymerizable mixture and cures at room temperature.

The application of the hydrochloride of organic bases can be carried out according to known methods Processes such as soaking or spraying and, advantageously, subsequent drying, take place. The substances are preferably used in the form of a solution. As a solvent all substances that are volatile and which can dissolve accelerators can be used will. Examples are methyl methacrylate, methyl acetate, acetone, methanol and water.

It goes without saying that this is the case when applying the accelerator ensure that the mat is equipped with sizing, finishing and finishing agents and is not removed with binders if possible. This can be done primarily through a professional selection of the solvent used is done. Feel like that for example mats that are impregnated using methanol or water have been soft and loose to the touch, while -man on the other hand when using for example methyl methacrylate or methyl acetate as a solvent a slight Can determine induration.

After this treatment, the substances are very finely distributed on the surface of the fibers, fabrics or mats. The fibers so treated are very durable and can be stored for almost any length of time.

The hydrochlorides of organic bases are in particular those of the tertiary Amines in question.

In the process according to the invention, the polymerizable mixture must essentially consist of a monomeric ester of acrylic or methacrylic acid; methyl methacrylate is preferably used. These mixtures are expediently used in syrupy form. They can preferably also contain up to 50 ″ of a polymeric substance. This group of substances preferably includes the polymers of the esters of acrylic or methacrylic acid. Mixtures with unsaturated polyester resins can also be used with advantage. It is also often used expedient -a part of the mixture -. concomitantly partially polymerized state Preferably, a monomer-polymer mixture is used of methyl methacrylate containing up to about 300/0 by polymethyl methacrylate, and a known process (known from the Belgian patent 572 made Rootstocks 359 and French patent specification 1 221 537) in a so-called "one-pot reaction", preferably using a sulfur-containing regulator, for example a mercaptan or its derivatives.

In many cases it is also advantageous to add further monomeric, polymerizable, organic compounds such as styrene, vinyl acetate, acrylonitrile, vinyl toluene, diallyl phthalate, allyl methacrylate, and generally crosslinkers such as ethylene glycol dimethacrylate, triallyl cyanurate, divinylbenzene and the like .

The polymerizable mixtures must be an indispensable component a peroxidic compound, preferably an organic PeroKyd, -optionally together with a hydroperoxide. You can also use other components an accelerator system known per se in the mass. For this belong e.g. B. copper and organic sulfur compounds, such as a-Anünosulfone, x-Oxysulfone, Mercaptans, sulfinic acid salts of organic bases.

As already stated, according to the process according to the invention, the hydrochloride of the organic base is applied in fine distribution to the surface of the fibers, mats, fabrics, strands and the like. In contrast to the previously known method in which the peroxide compound was applied to the mat, the present case is a storable structure. On the other hand, the polymerizable mixture, which contains only the peroxide catalyst and optionally one or more parts of the accelerator system, can also be stored, namely this mixture can be stored for several weeks at room temperature and for several months at lower temperatures. For example, 1.00 g of a syrupy methyl methacrylate mass containing 1.6 ml of tert-butyl perbenzoate (500% in dimethyl phthalate) and 0.2 g of bis (toloylsulfonmethyl) amine (500%) in dibutyl phthalate were found after 58 Days still unchanged.

When these mixtures are applied to the fibers, the accelerator components and the peroxide catalysts come into contact with one another, so that very rapid curing is made possible. This curing can be carried out with good success at room temperature and also at a very little elevated temperature. Another advantage of the process according to the invention is the fact that the polymerisation starts from the fiber, so that the synthetic resin shrinks onto the fiber. In addition, because the peroxide is evenly distributed in the synthetic resin compound . post-curing is made much easier and there is no risk of under-curing. The moldings produced by this process show a very good bond between fiber and resin, which greatly improves weather resistance and wet strength.

The production of fiber-reinforced moldings using the Heat curing is generally associated with the advantage of a long pot life, because the synthetic resin-forming mass contains only a peroxide as a catalyst. Disadvantageous What matters in this process is that with regard to the temperature supply and large expenditures are necessary for their precise regulation. This applies in intensified Dimensions in the manufacture of large components. In contrast, a Process which is carried out using cold hardening, by the Simplicity of its feasibility. In the method according to the invention falls also beneficial in weight that the quality of the moldings produced corresponds to shown after a hot curing process. With this one In addition, although it is a cold curing process, the short one falls Pot life gone. This is particularly advantageous when processing large quantities. Even if in the method according to the invention the initial hardness at any Position should be a little lower, this is irrelevant because it is mixed well distributed peroxide is able to bring about a considerable post-curing.

The constituents of the catalysts or accelerator systems used in the process according to the invention are known per se. The amounts in which these are advantageously used have also already been described several times. In the present case, however, it is recommended that the peroxide, based on 100 g of the polymerizable mixture in an amount of 0.5 to 2.0 "/" the hydroperoxides up to 1.00 / "the organic sulfur compounds up to 0, 5 0/0, the copper compounds in amounts of 10 to 3000 y and the hydrochlorides of organic bases in amounts of 0.01 to 0.5 0 / () to be used.

The process according to the invention is also particularly good for continuous Production of fiber-reinforced moldings suitable, and both the Impregnation with the hydrochloride of the organic base as well as application of the polymerizable mixture can be carried out continuously. For example the fiber web with the help of pairs of rollers over or through a trough-like or tub-like container are carried out and at the same time from above with the Solution of the accelerator or with the polymerizable mixture from a tank a spray device, which may have a mixing pot, if necessary, be sprayed or sprinkled. Applying the mixture is also done in the same way possible in the form of a film. At the same time, the molded body to be produced can be continuous be supplied with a foil.

B ice p y 1 A glass fiber mat is 15 g per their weight with 20 ml monomeric methyl methacrylate and 0.5 ml of a solution containing 1 g Phenyläthyldibutylaminhydrochlorid and 9 ml of styrene monomer containing, impregnated. All of the solution is soaked up by the mat. The mat is then air-dried for 6 hours. After this time, it is treated with monomeric methyl methacrylate, which contains about 300 liters, polymethyl methacrylate and small amounts of a mercaptan from the production. 50 g of this syrupy methyl methacrylate contained 0.05 ml of a solution of copper naphthenate in monomeric methyl methacrylate (1000, y Cu-I - + / ml) and 1.4 g of lauroyl peroxide paste (500% in dibutyl phthalate) and 0.07 ml of cumene hydroperoxide Solution (70% in alcohol, ketones and cumene mixture).

The curing time was 140 minutes at room temperature.

For comparison with the prior art, further tests were carried out in which all components of the catalyst or the accelerator system had been added to the polymerizable mixture, namely 0.5 ml of phenylethyldibutylamine hydrochloride solution were added to 50 g of the methyl methacrylate-polymethyl methacrylate mixture of the example (1 g of the hydrochloride dissolved in 9 ml of monostyrene) and 0.05 ml of Cu ++ solution (1000 y Cu-I - + / ml as naphthenate in methyl methacrylate) were added and mixed thoroughly. Finally, 0.8 ml of tert-butyl perbenzoate (50% in dimethyl phthalate) and 0.1 g of bis (tolysulfonmethyl) amine paste (500% in dibutyl phthalate) were mixed in. After a waiting time of about 5 minutes, which was used to remove the air bubbles present, the syrup formed was placed on a glass mat. The mat was soaked well with the syrup and then placed between two cellulose sheets and cured at room temperature. After a period of 30 minutes from the addition of the catalyst, the syrupy mass could no longer be processed. After a further 30 minutes, the hardening of the mass had progressed so far that it could be demolded and processed.

The processing time which is available when the process of the present invention is not used is 55 minutes for a mixture according to the example for a 20 g batch and 45 to 50 minutes for a 2 kg batch.

Claims (2)

Claims: 1. A process for the production of molded articles reinforced by glass fibers, synthetic or natural fibers based on polyacrylic or polymethacrylic acid esters by curing monomeric acrylic or methacrylic acid esters, optionally in the presence of polymers of these esters dissolved in these and optionally in the presence of a further monomeric, polymerizable compound with the aid of peroxide catalysts and optionally other customary accelerators, characterized in that the reinforcing material is pretreated with a hydrochloride of an organic base, then the polymerizable mixture is applied and cured at room temperature. 2. Process according to claim 1, characterized in that methyl methacrylate is used. 3. Process according to Claims 1 and 2, characterized in that the polymers used are polyacrylic or polymethacrylic acid esters, optionally in a mixture with unsaturated polyester resins. 4. The method according to claims 1 to 3, characterized in that one uses mixtures containing up to 5001, the polymer andlor up to 800 /, of further monomers polymerizable containing organic compound.