DE3937249A1 - Decorative mouldings from plastic scrap - by mixing crushed SMC and-or BMC scrap with curable thermosetting resin, hardener, opt. fillers, etc. and moulding and curing the mixt. - Google Patents

Abstract

Moulded plastic sheet with decorative surfaces (I) consists of (A) 20-60 wt.% crosslinked thermoset, (B) 10-70 wt.% inert filler, (C) 0-5 wt.% glass fibre, (D) 0.1-5 wt.% dyes and/or pigments and (E) 0-20 wt.% other normal synthetic resin additives; the novelty is that (I) contains 10-80 wt.% pulverised waste plastic with particle size (wt. average) 1-40 mm (II). (I) is produced by mixing (II) with a curable thermosetting resin, hardener, fillers, etc., forming and curing the mixt., and opt. polishing the surface of the prod. and/or applying an outer layer. More specifically (II) consists of crushed SMC and/or BMC parts. USE/ADVANTAGE - (I) is useful for the prodn. of wall panels (claimed). The invention provides a means of re-using fibre-reinforced thermoset scrap material. (II) is pref. coarsely crushed (e.g. in an impact crusher), mixed with unsatd. polyester resin, peroxide hardener etc. (e.g. on a twin-screw kneader), and compression moulded at 80-150 deg.C.

Description

The invention relates to plate-shaped plastic moldings with decorative Surface.

Reinforced thermosetting plastics are increasingly being used as replacements for metal and wood for the production of components in the automotive, Electrical and household appliance industry used. Particularly suitable Materials for this are unsaturated polyester resins, either with Glass fibers reinforced in flat form (SMC masses) or with fillers provided in dough form (BMC masses). examples for Components made from it are body parts, headlights reflectors, air intake manifolds, water pumps, leaf springs and steering columns of automobiles; Refrigerator housing, vacuum cleaner, electrical appliances, Mailboxes, telephone booths, also printed circuit boards and electronic Components. Due to the limited lifespan of the devices, the Elimination or recycling of plastic components problems. Components Thermoplastic materials can basically be melted be unlocked and reused; this is not the case with thermosets possible. Even in the manufacture of the components arise in more or less large amounts of waste. Such waste has so far been found on Landfills stored or burned, recycling methods were not previously known. The two methods mentioned for the disposal of Plastic waste is not satisfactory.

The invention was therefore based on the object of a way for recycling Show waste from fiber-reinforced thermosetting plastics.

This object is achieved in that the plastic waste in crushed form adds hardenable synthetic resins and from it plate-shaped Manufactures molded plastic parts.

The invention accordingly relates to plate-shaped Plastic molded parts with a decorative surface, consisting of

• A) 20-60% by weight of a cross-linked thermosetting plastic,
• B) 10-70% by weight of an inert filler,
• C) 0-50% by weight of glass fibers,  
• D) 0.1-5% by weight of dyes and / or pigments,
• E) 0-20% by weight of further conventional synthetic resin additives,

the molded parts having 10 to 80% by weight of shredded plastic waste an average particle size (weight average) between 1 and 40 mm contain.

Another object of the invention is a method for manufacturing the plate-shaped plastic molded parts, where you shredded Plastic waste with a hardenable thermosetting plastic and a Hardener and optionally fillers and other synthetic resin additives mixes, the mass forms and hardens and if necessary the surface of the molding obtained is polished and / or provided with a cover layer.

The following should be said about the individual components:

• A) As curable synthetic resins from which the cross-linked thermosetting Plastic is formed, unsaturated Polyester resins, vinyl ester resins, epoxy resins, polyurethanes, Phenolic, urea and melamine resins.
• Unsaturated polyester resins, which are generally preferred as Solutions of 80 to 40% by weight unsaturated polyester in 20 to 60% by weight of a copolymerizable monomer are present. The polyester are condensation products from polyvalent, especially divalent Carboxylic acids and their esterifiable derivatives, especially their Anhydrides with polyhydric, especially dihydric alcohols are linked ester-like, and optionally additional residues contain monohydric carboxylic acids or monohydric alcohols, wherein at least some of the starting materials are ethylenically unsaturated, must have copolymerizable groups. As a copolymerizable, ethylenically unsaturated monomeric compounds come the usual Allyl and vinyl compounds in question, preferably styrene.
• B) The molded parts contain 10 to 70, preferably 20 to 60% by weight. Fillers. Chalk is preferred. Besides that come too Glass balls, quartz sand, kaolin, aluminum oxide hydrate, silica gel, as well Metal powder in question. It is preferred to add some of the fillers add separately to the manufacture of the molded parts.
• C) The moldings contain 0 to 50, preferably 10 to 40 wt.% Fiberglass. These glass fibers, which are generally of medium length  from 0.5 to 10 mm, are preferred with the plastic waste the manufacture of the molded parts.
• D) The molded parts contain 0.1 to 5, preferably 0.2 to 4% by weight. Dyes and / or pigments. On the one hand, resin-soluble ones are preferred Dyes that are generally used for decorative purposes only when Production of the molded parts can be added separately, on the other hand insoluble pigments such as B. titanium dioxide or carbon black, which in general already contained in the plastic waste. Through the targeted addition of Titanium dioxide or mica can also be decorative or iridescent Streak effects are generated.
• E) Furthermore, the molding composition can be from 0 to 20% by weight of thermoplastics Anti-shrink additive, rubbers for elasticization, lubricants, Release agents and stabilizers included.

According to the invention, the molded parts contain 10 to 80, preferably 20 to 60% by weight of shredded plastic waste with an average particle size (Weight average) between 1 and 40, preferably 2 to 20 mm.

The shredded plastic waste essentially consists of cross-linked, thermosetting plastic, reinforcing fibers and optionally fillers and other additives. In addition - depending on the origin of the waste - minor amounts of thermoplastics, rests of elastic materials, e.g. As rubber, wood, cardboard, paper and metal particles may also be included. In general, the waste has the following composition:
20-80% by weight of thermosetting plastic,
10-40% by weight fibers, e.g. B. glass fibers,
0-70% by weight fillers, e.g. B. chalk.

Most of the plastic waste consists of used finished parts or from production waste based on glass fiber reinforced polyester resins, especially SMC and BMC components.

These parts are roughly crushed using granulators or impact mills. In In some cases, further crushing with beating machines, such as hammer mills or rotor mills. The crushed Plastic waste is then treated with a hardenable thermosetting synthetic resin, preferably again an unsaturated polyester resin as a binder mixed. A hardener, preferably a suitable peroxide, is used  added. If necessary, further fillers, Dyes, pigments and other synthetic resin additives can be added.

These raw materials are made on kneading tools, for example mixed on twin-shaft kneaders or pairs of rollers. It creates a dry sauerkraut-like mass.

Further processing into molded parts can be carried out on conventional presses. Depending on the type of hardener system added, it can be pressed cold or hot (preferably at 80 to 150 ° C.), the mass being deformed and hardened. If the bulk density of the plastic waste is very low, e.g. B. is less than 0.2 g / cm ³ , a cold pre-pressing before curing is recommended to displace air.

If necessary, the surface of the molded part can then be decorative be refined, e.g. B. by grinding, polishing, by applying Layers of lacquer or gelcoat.

The plate-shaped moldings are suitable as a replacement for Terrazzo artificial marble; they can be used as a floor, but preferably as Wall covering material can be used.

The parts and percentages given in the example refer to the Weight.

example

70 parts of an unsaturated polyester resin from a 67% styrenic solution of a maleic acid / polypropylene glycol polyester, 30 parts of polyvinyl acetate as an anti-shrink component and 150 parts of chalk as filler, 5 parts carbon black as pigment and 4 parts zinc stearate as Release agent and 1.7 parts tert. Butyl perbenzoate as a hardener becomes one Paste mixed.

In this paste, with continuous kneading on a Two-tongs mixer 250 parts of an SMC / BMC waste entered. The trash consists of 40% chalk, 30% glass fibers and 30% hardened Polyester resin, its average particle size is about 5 mm.

The molding compound becomes a 10 mm in a press frame at 150 ° C., 60 bar thick plate pressed. After 10 minutes the hardening is finished, the plate can be removed from the mold.  

After cooling, the plate is sanded with a belt sander and with a 0.5 mm gelcoat layer of light-curing Provide polyester resin based on isophthalic acid / neopentyl glycol.

Claims (5)

1. Plate-shaped plastic molded parts with a decorative surface, consisting of

• A) 20-60% by weight of a cross-linked thermosetting plastic,
• B) 10-70% by weight of an inert filler,
• C) 0-50% by weight of glass fibers,
• D) 0.1-5% by weight of dyes and / or pigments
• E) 0-20% by weight of further conventional synthetic resin additives,

characterized in that the moldings contain 10 to 80% by weight of crushed plastic waste with an average particle size (weight average) between 1 and 40 mm. 2. Plastic molded parts according to claim 1, characterized in that the Plastic waste from shredded SMC and / or BMC components consists. 3. A method for producing the molded plastic parts according to claim 1, characterized in that plastic waste with a curable thermosetting plastic and a hardener, and optionally Mixes fillers and other synthetic resin additives, the mass forms and hardens and optionally the surface of the obtained Molded parts polished and / or provided with a cover layer. 4. Use of the molded plastic parts according to claim 1 as wall tiles.