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GB2110585A - Catering trays having rough cork surface - Google Patents

Catering trays having rough cork surface Download PDF

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Publication number
GB2110585A
GB2110585A GB08134768A GB8134768A GB2110585A GB 2110585 A GB2110585 A GB 2110585A GB 08134768 A GB08134768 A GB 08134768A GB 8134768 A GB8134768 A GB 8134768A GB 2110585 A GB2110585 A GB 2110585A
Authority
GB
United Kingdom
Prior art keywords
cork
tray
sheet
resin
press
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08134768A
Other versions
GB2110585B (en
Inventor
Alan James
Bernard Frank Grayson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MALLINSON AND SONS WILLIAM
Original Assignee
MALLINSON AND SONS WILLIAM
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MALLINSON AND SONS WILLIAM filed Critical MALLINSON AND SONS WILLIAM
Priority to GB08134768A priority Critical patent/GB2110585B/en
Publication of GB2110585A publication Critical patent/GB2110585A/en
Application granted granted Critical
Publication of GB2110585B publication Critical patent/GB2110585B/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/02Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising animal or vegetable substances, e.g. cork, bamboo, starch
    • AHUMAN NECESSITIES
    • A47FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47GHOUSEHOLD OR TABLE EQUIPMENT
    • A47G23/00Other table equipment
    • A47G23/06Serving trays
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06Fibrous reinforcements only
    • B29C70/08Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
    • B29C70/088Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers and with one or more layers of non-plastics material or non-specified material, e.g. supports
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B38/08Impregnating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/16Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer formed of particles, e.g. chips, powder or granules
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00Containers; Receptacles
    • B32B2439/02Open containers

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)
  • Laminated Bodies (AREA)

Abstract

In the manufacture of catering trays by subjecting fibrous plies (1-7) impregnated with thermosetting resin to laminating heat and pressure, a sheet of granulated cork (8) is included in the assembly of plies so that it forms the top or part of the top surface of the tray. Under the laminating conditions, resin penetrates into the cork sheet, and the laminating pressure is released while the laminate is at an elevated temperature such that moisture is rapidly released from the cork and its surface spontaneously expands and acquires a rougher texture. <IMAGE>

Description

SPECIFICATION Catering trays This invention relates to a method of manufacturing moulded catering trays.
It is known to make trays by subjecting fibrous plies with a thermosetting bonding medium, e.g. a melamine-formaldehyde resin, to heat and pressure which result in a laminated moulded product. Such trays are used on a large scale in the catering industry, and domestically. They have non-porous surfaces and can easily be kept clean.
However they have the disadvantage that articles placed on them slide very easily.
It is an object of the present invention to provide a convenient rnethod whereby moulded laminated trays can be produced with an anti-slip surface.
According to the present invention there is provided a method of manufacturing a catering tray by subjecting fibrous plies with thermosetting bonding medium to laminating heat and pressure conditions in a moulding press, characterised in that the assembly of plies is introduced into the press together with a sheet of granulated cork for forming the top or part of the top surface of the tray; the assembly includes thermosetting resin located so that it penetrates into the cork sheet under the conditions in the press; and the laminating pressure is released while the laminate is at an elevated temperature such that moisture is rapidly released from the cork and its surface spontaneously expands and acquires a rougher texture.
The method according to the invention has the important advantage that the laminating step by which the fibrous plies are bonded together to form the moulded tray structure also serves to unite the cork ply to the laminate and at the same time reduces the water-absorbency of this cork ply in consequence of densification and resinimpregnation of the cork. This densification and resin-impregnation improves the resistance of the cork layer to mechanical damage and makes it easier for the cork layer to be kept hygienically clean. Of course the resin-impregnation must not be so extensive as to prevent the described modification of the surface of the cork which is responsible for the anti-slip properties.
The attainment of the anti-slip surface texture of the cork is compatible with such a degree of densification and resin-impregnation of belowsurface strata of the cork layer that the cork-faced tray can be safely repeatedly washed in hot water, even under the conditions obtaining in dishwashing machines. Appropriate laminate assemblies and appropriate laminating conditions for achieving this result are given by way of example later in this specification.
Preferably the densification and the degree of resin-impregnation of the cork effected in the press are such that the cork layer of the tray absorbs at least 10% but not more than 40% by weight of water based on the dry weight of the initial granulated cork sheet when the tray is immersed in water at 200C for 20 hours. Most preferably, the water-absorption of the cork under those conditions is at least 20% but not more than 28%.
The laminate forming the basic structure of the tray may be of a kind which is conventional in the manufacture of moulded trays from fibrous plies impregnated with thermo-setting resin. For example the laminate may comprise paper sheets, one or more of which may be printed (e.g. to simulate woodgrain), bonded with rnelamine- formaldehyde and/or phenol-formaldehyde resin.
Preferably the cork sheet is of smaller area than the tray and is centralised with respect to the other plies. The cork sheet can be held centralised by a jig preparatory to the laminating operation.
Pre-coating of the rear side of the cork ply with resin may precede the lamination step if desired but this has not been found to be necessary. The resin which impregnates the cork preferably derives entirely from a resin-impregnated sheet component of the initial assembly. Such component may for example contain at least 50% by weight of partially cured thermosetting resin.
Such a relatively heavily impregnated fibrous sheet can for example be a sheet of transparent alpha-cellulose tissue impregnated with melamine-formaldehyde resin.
The density of the cork sheet is preferably increased by a factor of at least 3 e.g. by a factor between 3 and 4 during the lamination. In certain very satisfactory embodiments of the invention the cork sheet has a thickness of from .8 mm to 1.7 mm prior to the laminating step and the pressure exerted during lamination is such that the thickness of the cork layer immediately prior to opening of the laminating press is between one fifth and two fifths of such initial value. For example, cork sheets originally of about 1 mm and 1.5 mm were reduced in the press to a thickness of about .3 mm and .45 mm respectively.
It is generally suitable to use a laminating pressure less than 1000 and preferably from 400 to 600 Ibs per square inch. The heating temperatures and the duration of the laminating pressure will depend on the composition of the thermosetting resin and of the laminate. Generally speaking temperatures of between 1 200 and 1 500C will be suitable. The time between full closure of the press and release of the laminating pressure will generally not need to exceed a few minutes but this period can be extended if required without loss of the required properties of the tray.
Following the extraction from the laminating press, an edge finishing operation may be carried out as known per se in moulded tray manufacture to smooth the edge of the tray.
The invention is illustrated by the following example in which reference is made to the accompanying diagrammatic drawings in which Fig. 1 represents an assembly of components prior to their subjection to heat and pressure in a laminating press and Fig. 2 shows in cross-section part of a tray made from that assembly.
EXAMPLE The assembly shown in the drawing, comprises an alpha-cellulose transparent overlay tissue 1, impregnated with melamine-formaldehyde resin, as marketed by Catalin Limited, Waltham Abbey, Hertfordshire under the trade mark "P304/43", a wood grain-printed paper 2 which may be impregnated with melamine-formaldehyde resin, as available from various trade printers, a second resin-impregnated tissue 3 identical with tissue 1, and a pack of thirteen phenolic core papers 4 (of which only a few are shown) such papers being marketed by Catalin Limited under the trade mark ''Corestock 2/531". On the opposite side of these core papers there are tissues 5, 6 and 7 identical with tissues 3, 2 and 1 respectively.The said sheets 1 to 7 will together orm the basic laminate structure of the tray. On the tissue 1 there is located a piece 8 of cork, this piece having been cut to size from 3 commercially available granulated cork sheet having a thickness of 1.5 mm and an equilibrium moisture content of from 6 to 12% by weight. The piece of cork is of smaller area than the said laminate plies 1 to 7 and is centralised with respect to those plies.
The assembly was placed between the dies of a tray moulding press, which dies had been preheated to and were maintained at a temperature of from 1320 to 2 4506. The press was closed to subject the assembly to a laminating pressure of 500 Ibs per square inch for 521 minutes. At the end of that period the press was opened and the tray while still hot was removed from the press and allowed to cool while weighted to prevent distortion. As shown by Fig. 2, by the treatment in the moulding press the assembly of plies 1 to 7 were integrated by the thermosetting resin into a laminated structure 9 having the form of a tray and at the same time the piece of cork 8 was bonded to such laminate. The piece of cork covered the major part of the area surrounded by the raised rim 10 of the tray.
The overall thickness of the cork layer in the finished tray was approximately 0.50 mm.
The tray was immersed in water at 200C for a period of 20 hours. Over that period of time the tray absorbed 22% by weight of water based on the dry weight of the original piece 8 of granulated cork. The tray was exposed to washing conditions in a dish-washing machine (washing liquid temperature 80 C) for a period of several days.
The tray was unimpaired by that treatment.
A plurality of trays can be simultaneously manufactured according to the above example in one and the same moulding press equipped with the requisite number of side by side pairs of moulding dies.
By way of modification of the above example, a plurality of wood veneers coated with thermosetting resin can be used, instead of the phenolic papers 4, such wood veneers combining to form in situ a ply-wood core.

Claims (6)

1. A method of manufacturing a catering tray by subjecting fibrous plies with thermosetting bonding medium to laminating heat and pressure conditions in a moulding press, characterised in that the assembly of plies is introduced into the press together with a sheet of granulated cork for forming the top or part of the top surface of the tray; the assembly includes thermosetting resin located so that it penetrates into the cork sheet under the conditions in the press; and the laminating pressure is released while the laminate is at an elevated temperature such that moisture is rapidly released from the cork and its surface spontaneously expands and acquires a rougher texture.
2. A method according to claim 1, wherein the densification and the degree of resin-impregnation of the cork effected in the press are such that the cork layer of the tray absorbs at least 10% but not more than 40% by weight of water based on the dry weight of the initial granulated cork sheet when the tray is immersed in water at 200C for 20 hours.
3. A method according to claim 2, wherein under the said immersion conditions the said cork layer absorbs at least 20% but not more than 28% by weight of water based on the dry weight of the initial granulated cork sheet.
4. A method according to any preceding claim, wherein the cork sheet is of smaller area than the tray and is centralised with respect to the other plies.
5. A method according to any preceding claim.
wherein the resin which impregnates the cork derives entirely from a resin-impregnated sheet component of the initial assembly.
6. A method according to claim 1 and substantially according to the Example herein.
GB08134768A 1981-11-18 1981-11-18 Catering trays having rough cork surface Expired GB2110585B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08134768A GB2110585B (en) 1981-11-18 1981-11-18 Catering trays having rough cork surface

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08134768A GB2110585B (en) 1981-11-18 1981-11-18 Catering trays having rough cork surface

Publications (2)

Publication Number Publication Date
GB2110585A true GB2110585A (en) 1983-06-22
GB2110585B GB2110585B (en) 1985-03-20

Family

ID=10525976

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08134768A Expired GB2110585B (en) 1981-11-18 1981-11-18 Catering trays having rough cork surface

Country Status (1)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170325610A1 (en) * 2016-05-12 2017-11-16 Cambro Manufacturing Company Serving Tray Incorporating Thermoplastic Polyurethane and Methods for Manufacturing the Same
US11083317B2 (en) 2016-05-12 2021-08-10 Cambro Manufacturing Company Methods for manufacturing serving tray with inner raised surface incorporating thermoplastic polyurethane

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170325610A1 (en) * 2016-05-12 2017-11-16 Cambro Manufacturing Company Serving Tray Incorporating Thermoplastic Polyurethane and Methods for Manufacturing the Same
US11083317B2 (en) 2016-05-12 2021-08-10 Cambro Manufacturing Company Methods for manufacturing serving tray with inner raised surface incorporating thermoplastic polyurethane
US11980307B2 (en) 2016-05-12 2024-05-14 Cambro Manufacturing Company Methods for manufacturing serving tray with inner raised surface incorporating thermoplastic polyurethane

Also Published As

Publication number Publication date
GB2110585B (en) 1985-03-20

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19921118