GB2221930A - Plastics toilet seat/lid - Google Patents

Description

2221930 l BOARDS AND COVERS FOR HYDROSANITARY CUPS The present invention

relates to boards and covers for hydrosanitary cups.

More particularly the present invention relates to boards and covers for hydrosanitary cups obtained by co-injection of thermoplastic resins and semi-foamed polymers.

As is known, boards and covers for hydrosanitary cups manufactured in plastics material are obtained by different processes and materials. Thus, boards and covers are known from urea-formaldehyde, phenol-formaldehyde thermosetting resins or from unsaturated polyesters; these latter, because of their brittleness when used without reinforcing glass fibers, are generally obtained by covering a wood chips core by casting, whereas the former ones are obtained by compression or injection molding.

ABS resins, polypropylene, anti-shock polystyrene, etc. are frequently used in the field or thermoplastic resins.

Thermosetting resins are brittle. and their aesthetic appearance is poor except polyester resins which show a good balance of aesthetic and functional 2 characteristics, but are of high cost because of the complex manufacturing process involving the formation of wood predies, cast covering, polymerization as well as long finishing operations (abrasion, trimming. etc).

Thermoplastic resins such as ABS resins and polypropylene give insuffiently stiff articles in that they are molded in relatively thin molds, because of both technical and economical reasons. with a high incidence of breakages near seams of fluxes and near optional hookings for hinges. Furthermore, since these articles are generally reinforced by means of ribs, residues can be formed which tend to make worse the aesthetic appearance of the finished article.

The Applicants have now found that above mentioned drawbacks can be overcome by using suitable thermoplastic materials either in semi-foamed or in stiff form.

The present invention provides boards and covers for hydrosanitary cups having a sandwich structure and comprising an inside core consisting of a semi-foamed (semi-expanded) thermoplastic polymer and an outside covering layer consisting of a compact thermoplastic resin.

3 ly the term semi-foamed thermoplastic polymer as used herein there is meant thermoplastic polymers having an average density from 0.4 to 0.9 kg/dm 3.

Any thermoplastic polymer able to provide semi-foamed articles can be used for manufacturing boards and covers of the present invention; examples of these materials are polymethylmethacrylate, polystyrene. polyvinylchloride, ABS, and polypropylene.

These polymers are added with pore forming agents of physical type such as nitrogen, Freon (registered trade mark), methylene chloride, and pentane, or of chemical type such as azoderivatives being for example azodicarbamide, hydrazine, and triazols.

The outside layer preferably consists of polymethylmethacrylate (PMMA) or high-impact polymethylmethacrylate (HI-PMMA); these resins are known products commercially available under different trade names such as Vedril (of Vedril 5.p.A.) of the types Vedril 90. Vedril 18V. Vedril 26V. etc.

Other materials which can be used for preparing the outside layer of the article of the present invention are ABS, polycarbonate, and polystyrene.

4 More particularly, boards and covers for hydrosanitary cups having an inside core consisting of a semi-foamed thermoplastic polymer having a thickness from 8 to 30 mm and an outside layer. adhering to the mentioned core, of a thickness from 0.5 to 3 mm are preferred.

Boards and covers for hydrosanitary cups according to the present invention can be obtained by techniques known in the literature. such as by co-injection; by this method, described in Modern Plastic International. July 1976, page 4 11Co-injection New Molding Technology", the compact thermoplastic resin is injected into a mould just before carrying out the subsequent co-injection of the polymer able to be foamed and in this way it is possible to carry out a continuous process which avoids the problem of pre-dies, their subsequent finishing processing as well as their arrangement into moulds.

By this method. manufactured articles are obtained having equivalent properties and in particular high stiffness. low weight. very good resistance to the screwing of self-tapping screws for applying hinges. very good impact resistance and complete absence of brittle breakages; furthermore. when an outside layer of PMMA or HI-PMKA is present. boards and covers of the present invention exhibit a very good aesthetic appearance because of the gloss of the used material.

1 the wide range of useable colours, the high surface hardness, the abrasion resistance of the cleaning agents and finally because of the possibility of re-polishing which cannot be performed when using other thermoplastic materials.

The invention will be further described. by way of example only, with reference to the accompanying drawings. wherein: figure 1 is a schematic front view and a top view of a board and cover comprising an article of the present invention; figure 2 is a schematic view of three sections of figure 1 obtained by planes passing through AA, BB and CC respectively.

With reference to the drawings. the article of the present invention comprises a cover 1. a board 2. and hinges 3 for connection with a hydrosanitary cup, fastened to the board and cover by means of selftapping screws 4 and bearing small blocks 5 and 6 for the board and the cover respectively, also fastened by means of self-tapping screws 41 and 411.

As shown by figure 2. both the board and the cover comprise an inside core 7 of semi-foamed material and a covering layer 8. constructed in compact material perfectly adhering to the mentioned core.

6

Claims (5)

1. An article comprising a board and/or a cover for a hydrosanitary cup having a sandwich structure and comprising an inside core of a semifoamed thermoplastic polymer and an outside covering layer of a compact thermoplastic resin.

2. An article as claimed in claim 1, wherein the semi-foamed thermoplastic polymer is selected from polymethylmethacrylate, polystyrene. polyvinylchloride, ABS, and polypropylene.

3. An article as claimed in claim 1 or 2. wherein the outside layer consists of polymethylmethacrylate or anti-shock polymethylmethacrylate.

4. An article as claimed in any of claims 1 to 3, wherein the inside core has a thickness from 8 to 30 and the outside layer adhering to the core has a thickness from 0.5 to 3 mm.

5. An article according to claim 1. substantially as herein described with reference to. and as shown in. the accompanying drawings.

Published 1990atThe Patent Office.State House. 66171 High Holborn, London WC1R4TP. Further copies maybe obtainedfrom The Patent Orace. Sales Branch, St Mary Cray. Orpingtor. Kei.t BR5 -'PD. Pr,rned by Multiplex techniques Ita, St Mary Cray. Kent. Con. 1187 4