GB2301793A

GB2301793A - Moulding a seamless aseptic door

Info

Publication number: GB2301793A
Application number: GB9611711A
Authority: GB
Inventors: Alphonsus O'mara
Original assignee: WEN PLAST
Current assignee: WEN PLAST
Priority date: 1995-06-07
Filing date: 1996-06-05
Publication date: 1996-12-18
Anticipated expiration: 2016-06-05
Also published as: GB2301793B; IES950420A2; GB9611711D0; IES66090B2

Abstract

A method for the manufacture of a seamless insulated aseptic door comprises providing two identically shaped moulds 10,20 of U-shaped cross-section; coating each mould with an isophthalic gel coat then with a polyester and then applying layers of glass tissue 13,14,23,24 glass fibre 15,16,25,26 and polyester in a defined pattern; providing a core element 17 in the first mould to be enclosed by the glass tissue and glass fibre: closing the mould by placing the inverted second mould over the first mould; pressing at 69.9-172.3kPa; removing the formed door from the mould and finishing it.

Description

This invention relates to a method for the manufacture of a door.

In particular, it relates to a method for the manufacture of seamless insulated aseptic door.

Seamless doors are required in environments where a very high standard of hygiene is required to the extent that the door should not have any cavity or crevices of any kind.

The invention, therefore, provides a method for the manufacture of a seamless insulated aseptic door which comprises the steps of: (a) providing two identically shaped first and second moulds each having a u-shaped cross-section; (b) laying on a respective isophthalic gel coat on each mould; (c) allowing the gel coat to tack cure so as to provide good adhesion characteristics; (d) laying on a respective first layer of a polyester on each mould; (e) at opposite ends of each mould, placing a respective layer of glass tissue allowing excess of tissue to fall over the respective ends of the mould; (f) providing a respective first layer of glass fibre throughout the extent of each mould; (g) laying on a respective second layer of a polyester on each first layer of glass fibre;; (h) providing a respective second layer of glass fibre throughout the extent of each mould and over the second layer of polyester; (i) providing a core on the first mould which core extends substantially the extent of the mould; (j) folding over the glass tissue over the core so as to embrace the glass fibre layers against the core; (k) inverting the second mould and offering it to the first mould to provide a combination mould and so that the respective layers of glass tissue are located externally of combination the mould; (1) placing the combination mould in a press at between 69.9kPa-172.3kPa (10-25 psi); (m) removing the combination mould from the press and removing the thus formed door therefrom; and (n) finishing the door.

Preferably, the combination mould is subject to pressure in step (i) for a period of between 70 and 80 minutes, preferably 75 minutes. Preferably, the combination mould is subject to pressure in step (i) at a temperature of between 170c and 220C, preferably 200C.

Preferably, the polyester layer comprises a pre-accelerated non-saturated amino polyester resin with a built-in inhibitor together with an organic peroxide which serves to provide a gel and subsequently cure the polyester resin.

The invention will be understood in greater detail from the following description of a preferred embodiment given by way of example only and with reference to the accompanying drawing which is a cross-sectional diagrammatic view of moulds and a door showing the stages of manufacture.

Referring now to the drawings, there is shown a first mould 10 and a second mould 20. In the course of manufacture of the door, both moulds 10, 20 are initially in the orientation of the first mould 10.

Each mould 10, 20 rests on a support (not shown) in theform of a trolley or table. However, the support for the first mould 10 has, at opposite ends thereof, respective uprights 30, 40 capable of having a first or lowered condition of use and a second or elevated condition of use.

The next described steps are common for both moulds 10, 20 and will be described with respect to the mould 10 with corresponding element numerals in respect of the mould 20 placed in parenthesis.

The mould 10 is substantially u-shaped in cross-section having opposite ends 11, 12 (21, 22). The mould 10 is coated with a layer of isophthalic gel coat which is allowed to cure until tacky. At each end 11, 12 is placed a respective layer of glass tissue 13, 14 (23, 24). In the case of the respective layers 23, 24 the ends 23a, 24a are somewhat longer than that of the layer 13, 14.

Next, there is provided a first layer 15(25) of glass fibre in the form of a blanket over the entire mould. The thickness of the layer 15(25) is approximately 0.45mm. Subsequently, the layer 15(25) is saturated with a first layer of a polyester. The polyester layer is preferably a pre-accelerated non-saturated amino polyester resin with a built-in inhibitor which, just prior to use, has been combined with an organic peroxide which, by chemical reaction, form a gel and subsequently cures the polyester resin.

Next, a second layer 16(26) is placed over the first layer 15(25) in the form of a blanket. The thickness of the second layer 16(26) is approximately 0.45mm. Now, with respect to the mould 11 only, there is now placed on the second layer 16 a core filler 17.

The core filler 17 has the same shape and configuration as that of the mould 11 but having slightly smaller dimensions. In addition the filler 17 may comprise any suitable material such as timber, PVC, cork, lead lined marine ply, urethane or a fire break material. A further polyester layer (not shown) is now given to, in the case of the mould 11, the core filler 17 and the surrounding second layer 16, and in the case of the mould 21, to the second layer 26. In the case of the mould 11, the ends of the glass tissue 13, 14 are placed over the core filler 17 so as to embrace it.

The mould 20 is now inverted and placed above the first mould 11. The uprights 30, 40 are placed in the elevated condition of use and the second mould 20 is lowered into position on top of the first mould 11 so that the edges thereof meet and can overlap. Because of the elevated condition of the uprights 30, 40 the ends 23a, 24a are positioned externally of the uprights 30, 40.

The combination now is then placed in a press (not shown) operating at a pressure of between 68.9kPa and l72.3kPa (10 and 25 psi) for a period of between 70 and 80 minutes, preferably 75 minutes at a temperature of between 170C and 22"C, preferably 200C.

At the end of the desired period, the combination mould is removed from the press, the thus formed door (not shown) is removed from the moulds 11, 21 and subject to a finishing stage.

The dimensions of such a door are approximately 825mm in width; 2040mm in length and 40mm in thickness.

There is thus provided a seamless insulated aseptic door particularly suitable for use in locations where hygiene is of significant importance.

The invention is not limited by or to the specific embodiment described which can undergo considerable variation without departing from the scope of the invention.

Claims

CLAIMS:

1. A method for the manufacture of a seamless insulated aseptic door which comprises the steps of: (a) providing two identically shaped first and second moulds each having a u-shaped cross-section; (b) laying on a respective isophthalic gel coat on each mould; (c) allowing the gel coat to tack cure so as to provide good adhesion characteristics; (d) laying on a respective first layer of a polyester on each mould; (e) at opposite ends of each mould, placing a respective layer of glass tissue allowing excess of tissue to fall over the respective ends of the mould; (f) providing a respective first layer of glass fibre throughout the extent of each mould; (g) laying on a respective second layer of a polyester on each first layer of glass fibre; (h) providing a respective second layer of glass fibre throughout the extent of each mould and over the second layer of polyester;; (i) providing a core on the first mould which core extends substantially the extent of the mould; (j) folding over the glass tissue over the core so as to embrace the glass fibre layers against the core; (k) inverting the second mould and offering it to the first mould to provide a combination mould and so that the respective layers of glass tissue are located externally of combination the mould; (1) placing the combination mould in a press at between 69.9kPa-172.3kPa (10-25 psi); (m) removing the combination mould from the press and removing the thus formed door therefrom; and (n) finishing the door.

2. A method as claimed in claim 1 wherein the combination mould is subject to pressure in step (i) for a period of between 70 and 80 minutes preferably, 75 minutes.

3. A method as claimed in claim 1 or claim 2 wherein the combination mould is subject to pressure in step (i) at a temperature of between 170e and 220C, preferably 200C.

4. A method as claimed in any of claims 1-3 wherein the polyester layer comprises a pre-accelerated non-saturated amino polyester resin with a built-in inhibitor together with an organic peroxide which serves to provide a gel and subsequently cure the polyester resin.

5. A method for the manufacture of a seamless insulated aseptic door substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.