WO2016012984A1

WO2016012984A1 - Vinyl adhesive composition and associated binding method

Info

Publication number: WO2016012984A1
Application number: PCT/IB2015/055618
Authority: WO
Inventors: Gabriele PERSONA
Original assignee: Legatoria Gps Srl Uninominale
Priority date: 2014-07-25
Filing date: 2015-07-24
Publication date: 2016-01-28

Abstract

A vinyl glue consisting of a water emulsion of polyvinyl acetate comprising conventional additives and characterized in that it comprises vegetable elastin. In a binding method a vinyl glue containing vegetable elastin is preheated, the vinyl glue is spread on the spine to be bound gripped along the edge by a press; a stabilizing gauze is applied on the spine; and the spine is spread with vinyl glue containing vegetable elastin.

Description

"Vinyl adhesive composition and associated binding method"

DESCRIPTION

The present invention relates to a vinyl adhesive composition and to an associated binding method.

Numerous types of polyurethane or animal-based synthetic and vinyl adhesive compositions are known in the present state of the art. Also known are methods for binding together a set of sheets with or without stitching in order to form a volume. In this description the term "volume" is understood as meaning an article formed by a plurality of paper sheets which are joined along the spine by a binding which is able to allow repeated opening operations for consultation of the single sheets or pages.

A first example of binding is the classic binding which is applied to books, referred to as "softback binding". In this type of binding the folded sheets are grouped and fastened together by means of a thread stitch and then a cover is applied by spreading a layer of polyurethane or animal-based glue.

A second example of binding which is often used consists of a very simple binding which envisages only the use of animal or polyurethane glue, without any stitching of the spine, but with milling of the spine before application of the glue, so that the latter may penetrate more easily between the sheets, albeit to a small depth.

The glues which are normally used in both methods are not vinyl-type glues, but are animal-based or of the polyurethane type.

As an alternative to animal-based or polyurethane glues, heat-meltable adhesives, which are essentially polyurethane-based, may also be used. These types of glues result in the bound spine being somewhat rigid and therefore application thereof is limited to a number of specific formats.

The present invention relates in particular to a stitchless binding which uses a vinyl type glue.

As is well-known to the person skilled in the art, bindings made using only vinyl glue, although they are extremely low-cost and simple to realize, have a number of structural limitations associated with the duration over time of the binding.

It is known in fact that, once the book has been opened and the pages turned over a given and often limited number of times, groups of sheets or single sheets tend to become detached from the rest of the book.

Moreover, one drawback of the bindings of the prior art, including those with stitching of the spine, is that the binding does not allow the volume to be opened so that two consecutive pages are substantially coplanar, namely with 180° opening. It is known in fact that, for example in a binding with stitching of the pages, opening of two adjacent pages is limited to values of less than 180°.

In a similar manner, the possibility of opening to 180° two adjacent pages is further impeded by the fact that, if the binding is to be efficient, using for example only vinyl glue, said glue must be absorbed by the paper at least minimally, but nevertheless sufficient for it to penetrate between the pages by a small amount.

The object of the present invention is therefore to solve at least partially the drawbacks of the prior art.

A first task of the present invention is that of providing a binding which is simple to realize and which at the same time is able to ensure a satisfactory result as regards the strength of the binding over time.

A further task of the present invention is to provide a binding which allows to obtain an opening to 180° of two consecutive pages.

The object and tasks are achieved with a vinyl adhesive composition according to claim 1 and an associated binding method according to claim 5.

Further advantageous characteristic features of the present invention are contained in the dependent claims.

The advantages and characteristic features of the present invention will emerge more clearly from the detailed description below of a number of examples of embodiment provided by way of a non-limiting example.

As is known, the vinyl adhesive composition is generally composed of a water emulsion of polyvinyl acetate, comprising conventional additives.

Polyvinyl acetate emulsions have a milky appearance and generally contain 50% of polyvinyl acetate, while the remaining 50% consists essentially of water and a small amount of protective colloid and dispersing agents.

The vinyl adhesive composition according to the present invention is characterized in that it comprises, in addition to the water emulsion of polyvinyl acetate with any additives, also a percentage by weight of vegetable elastin equal to at least 3%. Advantageously, the percentage by weight of vegetable elastin may be comprised between 3 and 7% and preferably between 3 and 5%.

Vegetable elastin is a protein which forms connective tissue. This protein is elastic and allows many tissues of the organism to return to their original form after being subjected to stretching or contractive forces. Elastin is principally composed of amino acids such as glycin, valine, alanine and proline.

It has now been found that the addition of this additive to vinyl adhesives generally increases their elasticity and their strength once dried, said characteristics making them optimum for use during the production of a binding. It has therefore been possible, both by using the new vinyl adhesive composition and by means of a particular method for applying the glue, to obtain a more elastic and stronger binding.

A binding method which is employed using the vinyl adhesive composition described above is now illustrated.

Before applying the vinyl adhesive composition, it is treated so as to reduce the water content present in the initial water emulsion of polyvinyl acetate for preparation of the vinyl adhesive composition.

The degree of reduction of the water content depends on the characteristics of the paper forming the sheets to be bound in the form of a volume.

In particular, it has been found that the quantity of water in the emulsion must be reduced to a percentage amount of between 30 and 40% by weight of the total.

Preferably, depending on the preferred mode of implementation of the method according to the invention, the said reduction in water content is obtained by preheating the vinyl adhesive composition to a temperature of between 20 and 55°C.

Heating may be advantageously performed by means of a water bath.

In particular, in the case where sheets of open-pore natural paper are to be glued together, the vinyl adhesive composition may be heated to a temperature of between 20 and 25°C. In the case where sheets of closed-pore coated paper are to be glued together, the temperature to which the glue may be heated may be between 50 and 55°C.

The resultant adhesive composition is then spread still hot on the spine to be bound while fixing the sheets along the spine by means of a press.

Then a stabilizing gauze is applied onto the spine and the entire assembly is dried inside an oven.

Finally, a further layer of vinyl adhesive composition is spread on the spine, on top of the stabilizing gauze, and drying in an oven performed.

Advantageously, during this step, the glue is heated to a temperature of between 20 and 55°C.

Once the spine is dry, it may be released from the press.

It is also possible to produce other variants of bound spine using sheets of ornamental elements such as cloth, lace, flock, imitlin, fabrics, silk or paper gauze with a hologram effect.

Another variant of spine may be obtained by means of the application of glitter using a compressor and a special glitter gun.

In accordance with an alternative embodiment of the present invention, the glue may also be coloured with non-toxic tempers commonly used for scholastic purposes. In this case, the glue is preferably at room temperature. With the vinyl adhesive composition and the binding method described above it is possible to obtain a binding with numerous advantages.

The binding which is obtained is particularly strong and elastic and is able to withstand repeated opening of the book without sheets or entire parts of the book becoming detached.

Moreover, the binding allows a 180° opening of adjacent pages, obtaining an aesthetic effect which could not be achieved with the bindings of the known type.

For example, it is possible to print images which extend over two adjacent pages so that, when the pages are opened 180°, there is continuity between the image on one page and the image on the other page.

Moreover, it also possible to bind effectively sheets of paper having different basis weights, ranging from 80 g to 1000 g, in any point of the book, or folded sheets which may then be opened (insets).

The binding is particularly strong also at temperatures below 10°C.

It is also possible to bind covers of various types: full bleed or with casing in or semi- cased, etc.

Advantageously it is also possible to detach several sheets from any point of the book without weakening the binding.

The person skilled in the art, in order to satisfy specific requirements, may make modifications to the embodiments described above and/ or replace the parts described with equivalent parts, without thereby departing from the scope of the accompanying claims.

Claims

1. Vinyl adhesive composition composed of a water emulsion of polyvinyl acetate comprising conventional additives,

characterized in that it comprises a percentage by weight of vegetable elastin of at least 3%.

2. Vinyl adhesive composition according to claim 1, characterized in that the percentage by weight of vegetable elastin is comprised between 3 and 7%.

3. Vinyl adhesive composition according to claim 2, characterized in that the percentage by weight of vegetable elastin is comprised between 3 and 5%.

4. Vinyl adhesive composition according to any one of the preceding claims, characterized in that it comprises 50% by weight of polyvinyl acetate, and the remaining 50% consisting of water, protective colloid, dispersing agents and vegetable elastin.

5. Binding method comprising the steps of:

pre-heating a vinyl adhesive composition according to any one of the preceding claims to a temperature of between 20 and 55°C;

spreading the vinyl adhesive composition on the spine to be bound gripped along the edge by a press, applying a stabilizing gauze on the spine; spreading on the spine a vinyl adhesive composition according to any one of the preceding claims.

6. Method according to claim 5, characterized in that in the finishing step spreading of the vinyl adhesive composition is performed at room temperature.

7. Method according to either one of claims 5 and 6, characterized in that it comprises a final step in which an ornamental element is applied onto the bound spine.