GB2034627A - Process for moulding reinforced articles from a hydraulic binder - Google Patents

Abstract

A process for producing reinforced articles made from a hydraulic material, e.g. cement, and a fibrillated film network, e.g. polypropylene, includes the steps of placing a mattress formed by a multiplicity of layers of fibrillated film in a mould, applying the hydraulic material to the mattress dewatering the hydraulic material and removing the green article from the mould. The mould may have a foraminous base and may be subjected to vibratory or tamping action.

Description

SPECIFICATION Process for laying-up reinforcement in a waterhardening mass This invention relates to a process for laying up a reinforcement in a water-hardening mass.

It has already been proposed in co-pending application 27371/76 in the names of the University of Surrey and D.J. Hannant, to reinforce a cementitious or other water-hardening mass with a plurality of networks arranged as layers, and this arrangement has been found to provide a product with many good properties.

The product cannot, however, be manufactured on conventional machines, such as are used for the manufacture of asbestos cement products, because the networks cannot be mixed in the waterhardening mass in a rotary mixer.

It follows that it is necessary to incorporate the networks by a laying-up process, which is inherently time-consuming and not suited to a high production rate.

According to the present invention the process for the production of reinforced sheets or other articles made from a water-hardening mass and an organic fibrillated film network includes the steps of providing a clean mould, placing a mattress formed by a multiplicity of layers of fibrillated organic film network having a number of layers as required in the final product, applying the water-hardening mass to the mattress in the mould, de-watering the waterhardening mass in the mould and withdrawing the green article from the mould.

The process will now be illustrated, by way of example, with reference to the accompanying diagrammatic drawing which illustrates in Figures la to 1 e the steps necessary for carrying out the process.

A clean mould with a foraminous base as illustrated in Figure la is supplied with a mattress made up of a plurality of layers of networks made for example of fibrillated, opened out polypropylene film. In the next stage in the process (Figure 1 c) a water-hardening mass, for example cement and fine sand or PFA is applied to the mattress while the mould is subjected to vibratory ortamping action to ensure good penetration of the mattress of polypropylene by the water-hardening mass.

In a subsequent step (Figure 1 d) de-watering action takes place through the foraminous base and a finishing roller or slide is applied and the green sheet is then removed from the mould.

In an unillustrated modification, the mould may be mounted on a continuous belt moving at a relatively slow speed, and the various steps of adding the mattress and applying the water-hardening mass may take place at successive stations along the path of the belt. At the turning point of the belt the green articles will be discharged. The belt may beforami- nous to assist the de-watering by application of a vacuum, and in this event it will be desirable that the belt should be subjected to a cleaning action at the return run to avoid blocking oftheforaminous surface by remaining cement and sane particles.

The mattress may be in accordance with copending application No. in the names of the University of Surrey, R.l.T. Williams, D. Hughes and S. Kekwick. This application discloses a mattress or composite built up of a woven layer and a multiplicity of layers of non-woven fibrillated organic film.

1. A process for producing reinforced articles made from a water-hardening mass and a fibrillated film network which includes the steps of providing a clean mould, placing a mattress formed by a multiplicity of layers of fibrillated film network in the mould, applying the water-hardening mass to the mattress in the mould, de-watering the waterhardening mass, and removing the green article from the mould.

2. A process as claimed in claim 1, which further includes subjecting the mould to a vibratory or tamping action to ensure good penetration of the mattress of fibrillated film network by the waterhardening mass.

3. A process as claimed in claim 1 or claim 2, in which the mould has a foraminous base through which de-watering of the water-hardening mass takes place.

4. A process as claimed in any one of claims 1 to 3, which further includes mounting the clean mould on a continuous belt conveyor.

5. A process of producing reinforced sheets made from a cementitions material and a fibrillated polypropylene film network, which includes the steps of providing a clean mould with a foraminous base, placing a mattress formed by a multiplicity of layers of fibrillated polypropylene film network in the mould, applying the cementitions material, subjecting the mould to vibratory or tamping action to ensure good penetration of the mattress of polypropylene by the cementitions material, de-watering the cementitions material through the foraminous base, and removing the green article from the mould.

6. A process of producing re-inforced articles, substantially as hereinbefore described, with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Process for laying-up reinforcement in a waterhardening mass This invention relates to a process for laying up a reinforcement in a water-hardening mass. It has already been proposed in co-pending application 27371/76 in the names of the University of Surrey and D.J. Hannant, to reinforce a cementitious or other water-hardening mass with a plurality of networks arranged as layers, and this arrangement has been found to provide a product with many good properties. The product cannot, however, be manufactured on conventional machines, such as are used for the manufacture of asbestos cement products, because the networks cannot be mixed in the waterhardening mass in a rotary mixer. It follows that it is necessary to incorporate the networks by a laying-up process, which is inherently time-consuming and not suited to a high production rate. According to the present invention the process for the production of reinforced sheets or other articles made from a water-hardening mass and an organic fibrillated film network includes the steps of providing a clean mould, placing a mattress formed by a multiplicity of layers of fibrillated organic film network having a number of layers as required in the final product, applying the water-hardening mass to the mattress in the mould, de-watering the waterhardening mass in the mould and withdrawing the green article from the mould. The process will now be illustrated, by way of example, with reference to the accompanying diagrammatic drawing which illustrates in Figures la to 1 e the steps necessary for carrying out the process. A clean mould with a foraminous base as illustrated in Figure la is supplied with a mattress made up of a plurality of layers of networks made for example of fibrillated, opened out polypropylene film. In the next stage in the process (Figure 1 c) a water-hardening mass, for example cement and fine sand or PFA is applied to the mattress while the mould is subjected to vibratory ortamping action to ensure good penetration of the mattress of polypropylene by the water-hardening mass. In a subsequent step (Figure 1 d) de-watering action takes place through the foraminous base and a finishing roller or slide is applied and the green sheet is then removed from the mould. In an unillustrated modification, the mould may be mounted on a continuous belt moving at a relatively slow speed, and the various steps of adding the mattress and applying the water-hardening mass may take place at successive stations along the path of the belt. At the turning point of the belt the green articles will be discharged. The belt may beforami- nous to assist the de-watering by application of a vacuum, and in this event it will be desirable that the belt should be subjected to a cleaning action at the return run to avoid blocking oftheforaminous surface by remaining cement and sane particles. The mattress may be in accordance with copending application No. in the names of the University of Surrey, R.l.T. Williams, D. Hughes and S. Kekwick. This application discloses a mattress or composite built up of a woven layer and a multiplicity of layers of non-woven fibrillated organic film. CLAIMS

1. A process for producing reinforced articles made from a water-hardening mass and a fibrillated film network which includes the steps of providing a clean mould, placing a mattress formed by a multiplicity of layers of fibrillated film network in the mould, applying the water-hardening mass to the mattress in the mould, de-watering the waterhardening mass, and removing the green article from the mould.

2. A process as claimed in claim 1, which further includes subjecting the mould to a vibratory or tamping action to ensure good penetration of the mattress of fibrillated film network by the waterhardening mass.

3. A process as claimed in claim 1 or claim 2, in which the mould has a foraminous base through which de-watering of the water-hardening mass takes place.

4. A process as claimed in any one of claims 1 to 3, which further includes mounting the clean mould on a continuous belt conveyor.

5. A process of producing reinforced sheets made from a cementitions material and a fibrillated polypropylene film network, which includes the steps of providing a clean mould with a foraminous base, placing a mattress formed by a multiplicity of layers of fibrillated polypropylene film network in the mould, applying the cementitions material, subjecting the mould to vibratory or tamping action to ensure good penetration of the mattress of polypropylene by the cementitions material, de-watering the cementitions material through the foraminous base, and removing the green article from the mould.

6. A process of producing re-inforced articles, substantially as hereinbefore described, with reference to the accompanying drawing.