GB2422593A

GB2422593A - Web-winding core

Info

Publication number: GB2422593A
Application number: GB0502078A
Authority: GB
Inventors: Steven John Morgan
Original assignee: DEVA COMPOSITES Ltd
Current assignee: DEVA COMPOSITES Ltd
Priority date: 2005-02-01
Filing date: 2005-02-01
Publication date: 2006-08-02
Also published as: GB0714588D0; GB0502078D0; WO2006082374A1; GB2439658A; GB2439658B

Abstract

A web-winding core comprises a rigid cylinder 1 having an elastomeric 2 covering disposed on at least a longitudinally central external part of the cylinder. A covering 4 may also be applied to the interior of the cylinder. The elastomer may be self-healing and may be a urethane. The elastomeric covering may have a Shore A hardness in excess of 60. The cylinder may be fabricated from Glass Reinforced Plastics (GRP), aluminium, steel, cardboard, polyvinyl chloride or fabric impregnated with a phenolic resin. The cylinder may be adapted so as to engage with a rotational driving member. In use, the web winding core is particularly suited to use with a web of a paper product.

Description

WEB-WINDING CORE

Background to the Invention

1] This invention relates to a web-winding core.

[00021 In the conventional manufacture of a product such as paper in the form of a web, the web is mechanically wound onto a rotating core member. Covers are commonly applied to web-winding cores to improve the performance of the winding process. The use of a cover diminishes the occurrence of damage to the web during winding, thereby reducing the necessity to discard deformed webs.

Deformable covers can accommodate irregularities in the web.

3] A number of different polymeric covers for core members have been described.

4] US-A-5,857,643 shows a core for winding a web of knurl-edged base material for photographic film. The core comprises a rigid cylinder having a soft deformable cover and harder end members for the knurled margins of the material.

5] EP-A-1,211,214 describes a core comprising a hollow cylinder covered by a water-resistant rigid sleeve of polypropylene, polystyrene, nylon, acrylonitrile butadiene styrene or a combination thereof. The sleeve has a hard polished outer surface that may be grinded down and repolished for reuse if necessary.

6] Web-winding cores are typically installed as a final component of a machine on which a paper product such as toilet tissue is manufactured. When a suitable length of material has been wound on a core, the core is detached from the machine and transferred to a separate location at which the web is unwound and processed further, e.g. divided longitudinally. Transfer of the heavy core requires a forklift, for example, and it is easy to damage the core.

Summary of the Invention

[00071 With the aim of providing a particularly robust core, the invention provides a web-winding core comprising a rigid cylinder and an elastomeric covering, the covering disposed at least on a longitudinally central and external part of said cylinder.

[00081 The outer surface of an existing core is hard and smooth. When unwinding a web from a core, it is usual to leave a number of turns of the material on the core to ensure consistent quality of the unwound web. These turns form a remnant, which is then cut off the core, e.g. manually; with a hard outer core surface the blade tends to deviate from the axial direction and there is a risk of injury. An elastomeric covering alleviates the risk and aids the cutting of the remnant.

[00091 If the covering is of a "self-healing" elastomer such as urethane, cuts therein will self heal. In prior art cores, such cuts mar the surface and create jags that may tear a web on a subsequent winding operation.

0] The rigid cylinder may be of a material typically but not exclusively selected from glass-reinforced plastics, fabric impregnated with a phenolic resin, aluminum, steel and cardboard.

1] In an embodiment of the invention, the interior of the core also comprises a layer of elastomeric material.

2] The core may comprise engaging means at at least one end of the core for engaging a rotational driving member of a winding apparatus.

3] The invention is suitable for winding webs of various materials, but is particularly apt for winding paper products, including tissue, such as toilet tissue, and label stock.

4] The invention additionally provides a web-winding core as defined above, bearing a wound length of a paper product.

Brief Description of the Drawing

5] Particular embodiments of the invention will now be described by way of example only, with reference to the single figure of the drawing, which shows a transverse cross section through a core according to the invention.

Detailed Description of Particular Embodiments

6] The core shown in the drawing comprises a rigid hollow cylinder I of glass-reinforced plastics material having a thickness of about 6mm.

[00171 A layer of urethane 2, e.g. 2-3 mm thick, is applied to the external surface of the cylinder 1. Suitable methods of applying the urethane layer include pouring, calendaring and application of the layer as a self-adhesive strip.

8] The urethane layer 2 is self-healing. It is selected to have a Shore A hardness of at least approximately 60 and thus to resist abrasion due to rough handling. The Shore A hardness may, for example, be between 60 and 100, and more particularly between 70 and 90.

[00191 As shown in the drawing, the outer surface of the urethane layer 2 has a knurled configuration. For example, there may be grooves 3 in the surface which intersect, e.g. at right angles, when the length of the core is viewed. This configuration may assist in picking up the end of a web of paper-based product.

For thermoplastic urethane the pattern is embossed by means of a hot tool, whereas for thermosetting urethane, the pattern can be formed by cold grinding.

However the knurled configuration is optional and we have found that a smooth outer surface is effective for certain paper-based webs.

[00201 An inner urethane layer 4 is formed on the inner surface of the cylinder 1.

Methods of application of the inner layer 4 include spraying, screeding, application via an adhesive carrier film that is adhered to the interior of the cylinder, casting in situ, mechanical fastening and combinations of these methods. The inner layer avoids damage to the core when the core is handled, for example by a forklift.

[00211 The core of the invention is optionally provided with engaging means at its ends for engaging driving machinery, which rotates the core about its axis at high speed.

[00221 Alternative materials for the cylinder 1 include strong fabric such as Keviar reinforced with a phenolic resin, polyvinyl chloride, aluminum, steel and cardboard. It will be appreciated that the thickness of the cylinder will vary if a material other than glass-reinforced plastics is used.

3] Elastomers other than urethane can be used for the outer layer and the optional inner layer.

[00241 Cores according to the invention can be reused thousands of times even when rotating at high speed. The cores have enhanced acoustic and vibrational properties. This is particularly important before winding commences and the bare core is pressed against a rotating drum of a papermaking machine.

[00251 All forms of the verb "to comprise" in this specification and the appended claims should be understood as forms of the verbs "to consist of" and/or "to include".

Claims

1. A core for winding a web of flexible material, comprising a rigid cylinder and an elastomeric covering, the covering disposed at least on a lotigitudinally central and external part of said cylinder.

2. A core according to claim 1, wherein the covering is of a self-healing elastomer.

3. A core according to claim 2, wherein the covering is of urethane.

4. A core according to claim 1, 2 or 3, wherein the rigid cylinder is of glass- reinforced plastics.

5. A core according to claim 1, 2 or 3, wherein the rigid cylinder is of a material selected from fabric impregnated with a phenolic resin, polyvinyl chloride, aluminum, steel and cardboard.

6. A core according to any preceding claim, wherein the covering is knurled.

7. A core according to any preceding claim, wherein the interior of the cylinder also bears a layer of elastomeric material.

8. A core according to any preceding claim, comprising engaging means at at least one end thereof, for engaging a rotational driving member of a winding apparatus.

9. A core according to any preceding claim, bearing a wound length of a paper product.