Method and injection molding system for producing intumescent reaction plastic molded parts and reaction plastic molded part

Abstract

A method for producing an intumescent plastic molded part that consists of a reaction plastic which contains intumescent additives and glass fibers is disclosed. The method includes providing an additive mixture which is composed of the intumescent additives and the glass fibers and mixing the additive mixture and components of the reaction plastic, where a homogeneous mass is obtained. The homogeneous mass is introduced into an injection mold and the homogeneous mass is hardened in the injection mold. A injection molding system for producing the intumescent plastic molded part and an intumescent plastic molded part are also disclosed.

Claims

1. A method for producing an intumescent plastic molded part that consists of a reaction plastic which contains intumescent additives and glass fibers, comprising the steps of: introducing the glass fibers into the intumescent additives in a mixing device and mixing the glass fibers evenly through the intumescent additives in the mixing device to form an additive mixture; introducing components of the reaction plastic by a pump into a mixing chamber through a first inlet of the mixing chamber; introducing the additive mixture from the mixing device into the mixing chamber through a second inlet of the mixing chamber; flowing a mass of the components of the reaction plastic and the additive mixture out of the mixing chamber through an outlet of the mixing chamber and into an injection mold; and hardening the mass in the injection mold.

2. The method according to claim 1, wherein the glass fibers have a diameter of 4 m to 10 m and a length of 3 mm to 10 mm.

3. The method according to claim 1, wherein a mass or a volume share of the additive mixture amounts to between 0.5% and 5% relative to the intumescent plastic molded part.

4. The method according to claim 1, wherein the produced intumescent plastic molded part is a foamed plastic molded part.

5. The method according to claim 1, further comprising the step of foaming the mass in the injection mold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts a molded part according to the invention, and

(2) FIG. 2 depicts an injection molding system according to the invention for producing the molded part from FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

(3) FIG. 1 depicts a plastic molded part 10 that consists of a polyurethane foam 12, which has evenly distributed intumescent additives 14 and glass fibers 16. Plastic molded part 10 has an essentially rectangular cross-section. Depending on the installation conditions and the intended use, any other shapes of the plastic molded part are possible.

(4) Such a plastic molded part 10 is used as a fire protection element, for example for wall or ceiling breaches. In the event of fire, intumescent additives 14 react with one another due to the increasing temperature and form a voluminous foam out of flame-retarding material so that the volume of plastic molded part 10 is increased. In the expanded state, plastic molded part 10 can seal the wall or ceiling breach and thereby prevent smoke or fire from spreading.

(5) The purpose of glass fibers 16 is to stabilize plastic molded part 10, both in the assembled state shown in FIG. 1 as well as in the foamed stated, and to increase its strength. To simplify the production of such a plastic molded part 10, one uses, instead of glass fiber mats or directional glass fibers, non-directional glass fibers having a length of 3 to 10 mm and a diameter of 4 to 10 m.

(6) The dimensions of 3 to 10 mm and a diameter of 4 to 10 m have proven to be ideal to ensure penetration of glass fibers 16 into small regions of an injection mold, even for more elaborate plastic molded parts. In addition, such glass fibers 16 offer sufficient stability of plastic molded part 10, without restricting its expansion properties in the event of fire. Since glass fibers 16 are present in a non-directional manner, uniform high stability is also created in all space directions. In addition, the complex orientation of the glass fiber mats is no longer necessary.

(7) FIG. 2 depicts an injection molding system 18 for producing such an intumescent plastic molded part 10.

(8) Injection molding system 18 has two storage tanks 20, 22 in which the components of the polyurethane foam (isocyanate, polyol) are stored separate from each other. Alternatively, there may be multiple storage tanks, wherein the components of the polyurethane foam are divided among multiple tanks, particularly when multiple polyols are used, and/or the additional components (catalyst, blowing agent, stabilizer, intumescent additives) are divided among multiple other tanks. In addition, lines 24, 26 are provided that lead from one of the storage tanks 20, 22 to a multicomponent and dosing system 27. Every line 24, 26 has a pump 28, 30 to deliver the respective base material from storage tank 20, 22 to multicomponent and dosing system 27.

(9) Multicomponent and dosing system 27 has a mixing head 32 with a mixing chamber 34. For each of the components, mixing chamber 34 has an inlet 36, 38, each of which can be connected to one of the lines 24, 26 to feed the components into mixing chamber 34.

(10) From the mixing chamber, an outlet 40 leads to an injection mold 42 that reproduces plastic molded part 10.

(11) To produce a conventional plastic molded part out of a polyurethane foam, the components of the polyurethane foam (isocyanate and polyol) are fed from storage tanks 20, 22 via lines 24, 26 to mixing head 32, blended in mixing chamber 34, and sprayed into injection mold 42, in which the mass foams and hardens. Injection mold 42 can thereby be designed as closed or open, wherein in the open design, the mold is sealed with a cover.

(12) In addition, mixing chamber 34 of injection molding system 18 according to the invention has an additional inlet 44 for an additive mixture of intumescent additives 14 and glass fibers 16. Alternatively, there may also be two inlets for additive mixtures, such as for separate dosing of the additives. The glass fibers can hereby be contained in only one additive inflow or in both additive inflows. As explained below, the additive mixture is produced out of glass fibers 16 and additives 14 in a mixing device 46.

(13) Mixing device 46 has a first reservoir 48 for intumescent additive 14 as well as a second reservoir 50 for glass fibers 16. Intumescent additives 14 as well as glass fibers 16 may be supplied from reservoirs 48, 50 via lines 53, 54 to mixing device 46, such as by being conveyed pneumatically. A pump or a dosing device may also be integrated in the mixing device for the additives. The glass fibers are thereby not conveyed via the pumps.

(14) In mixing device 46, glass fibers 16 are blended with intumescent additives 14 or macerated in it, and then fed via inlet 44 into mixing chamber 34.

(15) To achieve good blending of these substances, intumescent additives 14 are fluidized before introducing glass fibers 16, i.e., these are prepared in such a manner that they have fluid or pasty properties, in other words, they behave like a liquid. With the intumescent fillers in this state, an ideal blending with glass fibers 16 is possible. To fluidize intumescent additives 14, mixing device 46 has a dissolver for example.

(16) After fluidizing intumescent additives 14, glass fibers 16 are introduced into mixing device 46, wherein these combine with intumescent additives 14 into an additive mixture, whereby glass fibers 16 are evenly distributed.

(17) Subsequently, this additive mixture in multicomponent blending and dosing system 27 is fed via inlet 44 into mixing chamber 34 and blended in it with the components of the polyurethane foam (isocyanate, polyol), which are supplied via inlets 36, 38 into mixing chamber 34. After the additive mixture has blended with the components, this mass is introduced via outlet 40 into injection mold 42, foams up in it, and hardens.

(18) This manufacturing process has the advantage that it results in very little wear to injection molding system 18. Blending glass fibers 16 with the components of the polyurethane foam prior to introducing it into multicomponent and dosing system 27 would result in a rapid wear of pumps 28, 30 due to the hard glass fibers.

(19) For this reason, glass fibers 16 are introduced via a separate inlet 44 together with intumescent additives 14 into mixing chamber 34 so that pumps 28, 30 of lines 24, 26 do not come into contact with glass fibers 16 and are therefore not subject to increased wear.

(20) To achieve ideal fire protection, in other words to achieve the desired foaming properties in the event of fire, the mass or volume share of the additive mixture amounts to between 0.5 and 5% relative to the plastic molded part.

(21) In the embodiment depicted here, mixing head 32 has two inlets 36, 38 for the components of polyurethane foam 12. However, it is also conceivable that only one inlet is provided and the components of the polyurethane foam are mixed directly before being introduced into mixing head 32. Alternatively, more than two inlets are also possible, so that the individual components can be separated once again.