WO2000007825A1 - Business forms with adhesive closure - Google Patents

Abstract

A business form has one or more adhesive regions (3) provided with a non-tacky layer of a dry self-sealing contact adhesive (50) which is preferably an ammonia-stabilised rubber latex adhesive. The adhesive is selected to be self-sealable irreversibly to an opposed adhesive region also carrying the adhesive under a pressure of one MPa or less to hold the form in a folded condition suitable for mailing. The adhesive is also selected so as not to stick to opposed form surfaces when the forms are stacked. In the preferred forms, the adhesive region is in the form of a strip and the form is provided with lines of weakness, for example in the form of perforations (52), along and adjacent the adhesive strip for separating the region having the adhesive strip from the region on the other side of the line of weakness to allow easy opening of the folded form.

Description

BUSINESS FORMS WITH ADHESIVE CLOSURE This invention relates to business forms with adhesive closures and to the manufacture thereof. Use is particularly envisaged in relation to sealable mailers, i.e. forms or letters which have at least one printable region and which are to be folded after printing or the other appropriate mode of completion and sealed in the folded condition by means of one or more adhesive regions provided on the form, so as to be suitable for sending by post, or in some other manner in which it should remain sealed in the folded condition. The form may have e.g. a standard letter text with one or more printable fields for printing of selected data (e.g. address, name, file reference data) or a printed form layout or grid for completion with specific data by printer, typing or by hand.

Known mailers of this kind typically have one or more adhesive borders or strips for sealing them in the folded condition. Thus, forms sent out to the public or selected consumers for completion, sealing and return by way of response generally use a water-activated ("remoist") adhesive since this is easy and familiar for the ordinary recipient to use and requires no equipment . Conversely, mailer forms of the "direct mail" type designed for printing, completion, folding, sealing and sending as a large batch from business premises typically use a silicone-based contact adhesive on the form, sealed by high-pressure elements in a fast-throughput sealing machine. It is also known but less preferred to use a pressure-sensitive (high-tack) adhesive strip covered with a release layer.

What we now propose is a new and useful business form or mailer of the type described above which uses, as the or each adhesive region, a non-tacky layer of a dry self-sealing contact adhesive which self-seals irreversibly to an opposed adhesive layer of the same kind, when the form has been folded to its folded condition, under a sealing pressure applied on that region which is a finger pressure, or alternatively stated, a pressure of 1 MPa or less, preferably 500 kPa or less or 300 kPa or less, but preferably at least 10 kPa.

A form or mailer as proposed is in practice a dry seal form or mailer that can be sealed by hand without requiring the use of a sealing machine. Sealing machines are expensive, typically being engineered to exert pressures in the range 20 to 60 MPa (3000 to 8000 lb/in²) as required by the conventional dry-seal contact adhesives. Thus, the present proposals open the way for example to small-scale use of direct mail by organisations who for one reason or another cannot run a sealing machine. The proposal also opens the way to fold, seal and return response forms which can easily be used by the ordinary recipient without the need to wet an adhesive strip - a common source of discontent.

The reference above to an irreversible self-seal is to be interpreted as meaning that subsequent re- separation of the layers results in disruption at least of the adhesive structure, if not also in the base material.

The basis material of the form is a paper sheet. Generally, at least that zone of the sheet adapted for printing or other recordal of indicia is a single- thickness continuous sheet, in contrast for example with an envelope. Desirably the entire sheet is a single- thickness continuous sheet. For obvious reasons the sheet is usually rectangular.

In preferred embodiments a non-adhesive region of the sheet - which may be essentially the entire area of the sheet - is surrounded by a continuous border of adhesive region carrying the non-tacky layer of selected contact adhesive. Opposed regions of this border can be superimposed by folding the sheet appropriately, e.g. once in half (V-form) , once but not in equal halves (offset V) or twice in thirds (C-form or Z-form) . In particularly preferred embodiments adhesive strips extending right across the paper sheet have a corresponding adjacent line of weakness for separating the region having the adhesive strip from the region on the other side of the line of weakness by tearing. For example, an adhesive border may be provided as described above for all or part of the sheet which forms a sealed enclosure when folded over. A tearing line, such as a line of perforations, can be provided along an inside edge of the adhesive border so that the sealed form can be re-opened by tearing away the stuck-together border regions and unfolding the remainder. This is in itself well-known and other combinations and arrangements will be apparent to a skilled person. It is highly desirable that business forms according to the present invention are easily printable, and especially using a printer such as a laser printer, or bubble jet or other printer. Preferably therefore the paper sheet is printable, especially laser-printable and the dry self-sealing contact adhesive can withstand printer conditions, in particular high temperature, without detaching or becoming tacky so as to contaminate the printing machine.

The form may be provided with printer drive engagement locations, such as one or more longitudinal series of perforations to be engaged by a form feed drive sprocket or belt. Such a series of drive perforations may conveniently be provided along side edges of the form, preferably alongside a line of weakness such as a perforated line enabling the drive-perforated strip to be easily torn away after printing. An adhesive border as previously discussed, optionally with its respective preformed line of weakness running along its inner edge, may be positioned alongside the drive perforation strip. Because the adhesive is a low-pressure contact adhesive it is preferred that the adhesive regions are disposed on the sheet such that, when two of the business forms are placed one on top of the other in the same orientation, there is no contacting overlap between said adhesive regions of the forms. By means of this feature the forms can be stacked without fear of unwanted sticking.

The adhesive is selected and applied so as to provide low tack. Again, this is important for preventing premature sticking. Selection and application to achieve no effective tack are usually routine matters for a skilled person. In particular it should be noted that preventing tack with a low-pressure sealing adhesive generally requires a sufficiently thin layer to be applied. Thicker layers may be prone to tackiness. For a given adhesive the appropriate thickness can generally be determined by trial and error. Preferably the tack is adjusted so that in a continuous free vertical stack of 2000 of the forms, with the adhesive regions opposed to paper surfaces, there is no adhesion between forms causing bodily displacement of one form when the form above it is lifted away.

We have found that elastomer latex adhesives are suitable for the present purposes, for example those made using natural rubber or synthetic approximations thereto. The techniques and equipment used for applying the adhesive may be in themselves conventional . The adhesive is preferably applied as a strip or band to the basis paper sheet. The width of such band is preferably from 3 to 8 mm.

An example of the invention is now described with reference to the accompanying drawing, in which Figs 1 and 2 are front and back views of a one-piece mailer.

With reference to Figs 1 and 2, a printable invoice form in one-piece mailer format consists essentially of a single, flat rectangular sheet of paper. The obverse 1 of the form (Fig 1) is pre-printed with an appropriate invoice layout, including the name and address 11 of the organisation sending the invoice, a printed address field 12, a printed date field 13 and a printed invoice data field 14. The fields 12,13,14 represent areas where data will be filled in by a printer, typewriter or by hand, according to the specific case. The illustrated form is designed to be form-feedable into a feeder with a form drive, by virtue of side strips 6 with respective series of perforations 61 for engagement by the teeth of a printer drive sprocket. A line 62 of fine perforations joins each drive strip 6 to the remainder of the form, which remainder is of standard size e.g. A4. Thus, a series of these forms can if wished be fed through a printer and the fields 12,13,14 etc. completed in accordance with electronically-stored data if wished.

The obverse 1 of the form has a peripheral rectangular region 3 thinly coated with a continuous layer of dry-seal contact adhesive 50. The adhesive region or strip 3, for example 5 mm wide, extends right around the periphery of the standard size sheet. Perforated lines 52 also extend right around the sheet edge along the inner edge of the adhesive border 3. These perforations 52 provide a means - in itself known to the skilled person in this field - by which the adhesive region 3 can be torn away from the non-adhesive main area of the sheet as two side strips 5 and two end strips 4. Fig 2 shows the reverse 2 of the sheet which may be pre-printed e.g. with a return address 16 and a location 17 for pre-paid or stamped postage, but in this embodiment is not to be printed in use of the business form itself. Characteristic of the present one-piece mailer is the nature of the adhesive layer 50 on the adhesive border zone 3. The adhesive 50 is selected and applied as an essentially tack-free layer - which will therefore not stick to opposed paper surfaces e.g. if the forms are stacked - which will self-adhere on contact with another part of the adhesive region 3 under finger pressure only. The present example uses a natural rubber latex adhesive stabilised with ammonia. In our work we used L516/4 adhesive supplied by Sealock. When applied as a sufficiently thin layer this adhesive is essentially tack-free .

After printing or writing of the relevant fields, the one-piece mailer invoice is used by folding the sheet in half about the centre line 18 to superimpose the opposed C-lines of the adhesive region 3. These are then pressed together using finger pressure, which creates an irreversible adhesive bond on contact. The printer-drive strips 6 are then torn away by means of the outer perforation lines 62 and discarded so that the mailer can be sent out. It acts as its own envelope concealing the data on the invoice, in the known manner. The recipient of the completed document can open it by tearing away the adhesive side strips 5 and end strips 4 by means of the inner perforation lines 52. The skilled person will appreciate that the present invention is applicable with variants of the one-piece mailer format. It may be desired to apply the selected contact adhesive on both obverse and reverse e.g. in order to adopt fully-sealed C-fold or Z-fold configurations. In this case it will normally be necessary to provide adhesive regions on the obverse which should not overlap adhesive regions on the reverse when two of the forms are superimposed in the same orientation. The proposal may also be implemented over less than the whole of an original sheet. For example, an initial document may be a larger sheet (e.g. A3) of which the form with the selected adhesive as described herein forms a detachable part (e.g. A4) . This is a useful format when a form is required for response to a message.

Claims

1. A business form with an adhesive closure having one or more adhesive regions for holding the form in a folded condition, characterised by the use on the adhesive region of a non-tacky layer of a dry self-sealing contact adhesive, which in the folded condition is self-sealable irreversibly to an opposed adhesive region also carrying a said contact adhesive, the adhesive being selected to self-seal irreversibly under a pressure of one MPa or less.

2. A business form according to claim 1 in which said contact adhesive is selected to self-seal irreversibly under a pressure between 10 kPa and 300 kPa .

3. A business form according to claim 1 or 2 in which said contact adhesive is an elastomer latex adhesive.

4. A business form according to claim 3 in which the adhesive is a natural rubber latex adhesive stabilised with ammonia .

5. A business form according to any one of the preceding claims which is a single-thickness continuous sheet.

6. A business form according to any one of the preceding claims in which the adhesive region is provided as a border around a paper sheet constituting the form.

7. A business form according to any one of the preceding claims in which the adhesive region is provided as one or more adhesive strips extending right across the paper sheet constituting the form, and a line of weakness is provided along and adjacent a said adhesive strip for separating the region having the adhesive strip from the region on the other side of the line of weakness by tearing.

8. A business form according to any one of the preceding claims made from laser-printable paper sheet.