Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1994-02-22
1994-11-29
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
526301, 526319, 526328, 5263285, 526329, 526312, 528 75, 2643281, 2643286, 2643288, C08L 7504
Patent
active
053691768
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a composition to be used in the Resin Injection Moulding technique, which composition substantially contains low molecular weight compounds capable of forming a hybrid network, which composition at least contains a first component consisting of a compound with at least an ethylenic unsaturation and an isocyanate-reactive group, and a second component containing an ethylenically unsaturated monomer capable of copolymerizing with the first component, and a third component, which is a polyisocyanate.
Such a composition is described in U.S. Pat. No. 4,822,849. In it the first component is an unsaturated polyester with terminal hydroxyl groups. Such a composition has been found to have the disadvantage that it shrinks during the curing. U.S. Pat. No. 4,822,849 provides a solution for it by reducing the number of unsaturations in the prepolymer, so that the shrinkage resulting from the radical polymerization is reduced. However, the disadvantage of this measure is that the mechanical properties of the material deteriorate in consequence of the reduction of the crosslink density. At the same time, the viscosity of the composition is rather high. In certain applications this is a disadvantage.
The object of the invention is to provide a low viscosity composition with which products with good mechanical properties may be obtained.
An other object of the invention is to provide a low viscosity composition with which products may be obtained with little or no polymerisation shrinkage.
This is achieved according to the invention in that the composition is a composition of monomers with a molecular weight lower than 1000, the first component of which substantially consists of a monomer with substantially 1 terminal vinyl group per molecule and further substantially 1 isocyanate-reactive group per molecule and has a molecular weight lower than 500.
From DE-A-2,209,149 a composition is known containing, inter alia, an ethylenically unsaturated monomer and an adduct of a polyisocyanate and a monomer with an isocyanate-reactive group and a terminal vinyl group, but in it, before mixing the adduct with the ethylenically unsaturated monomer, the polyisocyanate is first prepolymerized, at least in part, with a polyol and with the monomer with the isocyanate-reactive group and the terminal vinyl group. This composition does not exhibit a low viscosity. With the known composition a reduction of the polymerisation shrinkage according the invention is not possible. DE-A-2,209,149 does not mention that this composition can be used for the Resin Injection Moulding (RIM) technique.
From U.S. Pat. No. 3,856,830 a composition is known containing a polyisocyanate and also a monomer with an isocyanate-reactive group and a terminal vinyl group. The polyisocyanate reacts with this monomer to form a urethane oligomer with terminal unsaturations which is capable of polymerizing, optionally in the presence of an ethylenically unsaturated monomer. So, in U.S. Pat. No. 3,856,830, there will first be a reaction of the polyisocyanate with the monomer with the unsaturation and with the isocyanate-reactive group and only after that a composition is obtained of the reaction product with an ethylenically unsaturated monomer.
This composition does not exhibit a low viscosity. With the known composition a reduction of the polymerisation shrinkage according the invention is not possible.
U.S. Pat. No. 3,856,830 does not mentioned that the composition can be used for the RIM technique.
From EP-A-197682 a polymerisable composition is known comprising an ethylenically unsaturated monomer, a low profile additive and an adduct of a polyisocyanate and a monomer with an isocyanate reactive group and a terminal vinyl group. The polyisocyanate is always completely converted into an unsaturated urethane monomer. The low profile additive is an organic polymer. The know polymerisable composition has the disadvantages that first an unsaturated urethane monomer has to be synthesized and that the low profile additive has to be solved into the
REFERENCES:
patent: 4041104 (1977-08-01), Selley
patent: 4287116 (1981-09-01), Burns
DSM N.V.
Welsh Maurice J.
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