EP0107576A2 - Polyvinyl alcohol film with retarded water-solubility, process for its preparation and its use in burying dead bodies - Google Patents

Abstract

1. Method for the production of a device for burying dead bodies, comprising a polyvinyl alcohol film with retarded aqueous dissolution, obtained from a saponified polyvinyl alcohol resin, characterized in that a film is utilized such as : - its thickness is comprised between 30 and 100 mu m ; - the basic polyvinyl alcohol resin contains a proportion by weight of residual unsaponified vinyl acetate which is comprised between 0,2 and 0,7% ; - said film comprises in its body a plasticizer and an anti-blocking agent ; and - before removal of water useful for aqueous dissolution, the composition by weight of said film is approximately as follows : - polyvinyl alcohol resin : from 45 to 60% - plasticizer : from 5 to 20% - anti-blocking agent : from 0,05 to 0,2% - water : amount sufficient for aqueous dissolution of the resin.

Description

Polyvinyl alcohol film with delayed aqueous dissolution, its manufacturing process and its application to the burial of corpses.

The present invention relates to a polyvinyl alcohol film with delayed aqueous dissolution, its manufacturing process and its application to the burial of corpses.

It is known that polyvinyl alcohol films are obtained from polyvinyl alcohol resin granules, themselves obtained by polymerization, aqueous dissolution, and then saponification of the vinyl acetate produced by the action of acetic acid on acetylene. These granules are then dissolved in water, heated and added with various components and the aqueous mixture obtained is shaped into a film, for example by calendering or extrusion blow molding.

In general, polyvinyl alcohol films are soluble in water and it is known, by means of thermal or chemical treatments for example, to adjust the solubility of a polyvinyl alcohol film as a function of the temperature. water in which said film is immersed.

The object of the present invention is to produce a polyvinyl alcohol film whose aqueous dissolution, instead of being practically instantaneous as for known films, is delayed in time by a few months; the film according to the invention can then be used, among other applications, for the production of shrouds, body covers, coffin bowls, etc.

We know that, today, the dead are only buried several days after their death and that they are not put into beer until the day of the burial. As a result, the bodies are exposed, generally on a bed, several days before being buried, and that, especially in hot weather, the decomposition of said bodies is sufficiently advanced before putting in beer to cause the emission of odors foul-smelling and to raise hygiene issues.

• - masquer les imperfections du bois du cercueil,
• - et surtout réaliser une cuvette étanche pour pallier les effets de la désagrégation des corps dans le temps.

Furthermore, it is known that the coffins have an inner padding constituted by a plastic film of white polyvinyl chloride. This 100 micron plastic sheet has a dual role:

• - hide imperfections in the coffin wood,
• - and above all to make a watertight bowl to mitigate the effects of the disintegration of the bodies over time.

• - le chlorure de polyvinyle n'est absolument pas biodégradable et se retrouve toujours, même après une période de mise en terre très longue.
• - quand l'on veut procéder à des réductions de corps ou des exhumations ce qui est assez courant, les personnels qui effectuent cette opération se trouvent toujours en présence de ces cuvettes qui sont restées étanches et qui par là même contiennent tous les éléments de décomposition avec le grand nombre d'inconvénients majeurs que cela entraîne.

The realization of this waterproof polyvinyl chloride bowl poses the following problems:

• - polyvinyl chloride is absolutely not biodegradable and is always found, even after a very long planting period.
• - when we want to carry out body reductions or exhumations which is quite common, the personnel who carry out this operation are always in the presence of these basins which have remained watertight and which thereby contain all the elements of decomposition with the large number of major drawbacks that this entails.

It is therefore interesting to make a bowl which, after a few months (5 to 6 approximately), under the effect of the decomposition of the corpse, disintegrates gradually and so that the results of decomposition are eliminated in the soil.

Thus during exhumation operations or reduction of bodies, the personnel is only in contact with dried residues, therefore without liquid or strong odor.

For these purposes, according to the invention, the polyvinyl alcohol film with delayed aqueous dissolution, obtained from saponified polyvinyl alcohol resin, is remarkable in that its thickness is chosen between 30 and 100 u and in that the basic polyvinyl alcohol resin contains a proportion by weight of residual vinyl acetate, not saponified, of between 0.2 and 0.7%.

Indeed, it has been found that one could act on the duration of the dissolution of a film of polyvinyl alcohol by varying the proportion of non-saponified residual vinyl acetate. Consequently, by adjusting this proportion of residual vinyl acetate as a function of the thickness of the film, it is possible to delay the apparent onset of aqueous dissolution.

Of course, the polyvinyl alcohol film according to the invention can be used for all the applications for which a delayed dissolution film is required. However, as mentioned above, the film according to the invention is particularly suitable for being used to make shrouds, body covers, coffin bowls, etc., which must have great mechanical resistance for a few tens of days. following their bringing into contact with the body of a dead being and corresponding to the manipulations and the presentation of said body before its burial, but entirely biodegradable after several months of contact, that is to say after burial.

The polyvinyl alcohol film according to the invention can be obtained, in a known manner, by extrusion blow molding or by calendering. However, it seems preferable to use the calendering method (continuous casting).

To allow a good casting or extrusion of the base mixture of polyvinyl alcohol resin, it is advantageous to incorporate into this base mixture a plasticizer of the glycerin type.

When the film obtained either by calendering or by extrusion blow molding is continuously wound in a reel, it is advantageous to incorporate into the mass of the basic mixture, an anti-blocking agent, such as metal stearates and / or ethoxylated polyols, in order to prevent the different turns of the coil from sticking to each other.

One could also carry out, at the level of the winding, a projection of starch or a similar body to obtain an analogous result.

• - Résine d'alcool polyvinylique (présentant une proportion d'acétate de vinyl résiduel de 0,2 à 0,7 %) : de 45 à 60 % ;
• - Plastifiant : de 5 à 20 % ;
• - Agents anti-blocking : de 0,05 à 0,2 %
• - Eau : quantité suffisante pour la dissolution aqueuse de la résine.

Preferably, before removing the water used for aqueous dissolution, the composition by weight of the polyvinyl alcohol film according to the invention is approximately as follows:

• - Polyvinyl alcohol resin (having a proportion of residual vinyl acetate from 0.2 to 0.7%): from 45 to 60%;
• - Plasticizer: from 5 to 20%;
• - Anti-blocking agents: from 0.05 to 0.2%
• - Water: sufficient quantity for the aqueous dissolution of the resin.

In order to make the film obtained opaque, opacifiers can be added thereto, such as titanium dioxide and calcium carbonate, in a proportion by weight of between 10 and 25%. It will be noted that such an opacifier indirectly plays the role of retarder of aqueous dissolution, since it influences the initial quantity of water necessary for the aqueous dissolution of the resin.

Thus, to obtain a film according to the invention, a process is used in which a polyvinyl alcohol resin is used, the saponification of vinyl acetate of which is such that the proportion by weight of non-residual vinyl acetate saponified, is between 0.2% and 0.7% and a film is produced whose thickness is between 30 and 100 μ.

• - Résine d'alcool polyvinylique : de 45 à 60 %
• - Plastifiant de 5 à 25 %
• - Agents anti-blocking de 0,05 à 0,2 %
• - Eau : quantité suffisante pour la dissolution aqueuse de la résine.

In addition, it is advantageous that the initial base mixture, from which this film will be made, contains approximately:

• - Polyvinyl alcohol resin: 45 to 60%
• - Plasticizer from 5 to 25%
• - Anti-blocking agents from 0.05 to 0.2%
• - Water: sufficient quantity for the aqueous dissolution of the resin.

Preferably, the process for manufacturing the polyvinyl alcohol film in accordance with the present invention is of the so-called "calendering" type, in which all of the components, including water, are mixed continuously and the aqueous mixture is heated, then said mixture is spread on a calender where it is heated for spreading and evaporation of water.

According to the invention, before spreading on the grille, the aqueous mixture is heated to a temperature between 80 and 95 ° C. Indeed, it has been noted that the temperature at which the mixture was spread on the calender also had an influence on the aqueous solubility of the film obtained. The range between 80 and 95 ° C is particularly favorable for the result to be obtained.

Preferably, the aqueous mixture is subjected to deaeration before spreading.

A particular embodiment is described below.

• - 57 kg de granulés de résine d'alcool polyvinylique (ayant un taux résiduel d'acétate de vinyl égal à 0,3 %) ;
• - 14 kg de glycérine à titre de plastifiant;
• - 17 kg de dioxyde de titane et de carbonate de calcium à titre d'opacifiants ;
• - 0,5 kg d'acide borique à titre de stabilisant ;
• - 0,2 kg d'alkyl aryl ^polyether à titre d'agent mouillant ;
• - 0,15 kg de stéarates métalliques et de polyols ethoxylés à titre d'agents anti-blocking ;
• - 11,15 litres d'eau.

To make an 80 µm thick film, the following products are poured into the tank of a mixer:

• - 57 kg of polyvinyl alcohol resin granules (having a residual vinyl acetate content of 0.3%);
• - 14 kg of glycerin as plasticizer;
• - 17 kg of titanium dioxide and calcium carbonate as opacifiers;
• - 0.5 kg of boric acid as stabilizer;
• - 0.2 kg of alkyl aryl ^p olyether as wetting agent;
• - 0.15 kg of metal stearates and ethoxylated polyols as anti-blocking agents;
• - 11.15 liters of water.

The aqueous mixture is heated to 85 ° C. and after complete dissolution of the components, the mixture is transmitted to a deaeration tank, then to a spreading calender adjusted to the thickness of 80 μ. The calender is heated to evaporate the water from the film and the film is dried, then wound in a reel.

To determine the mechanical and physical properties of this film, it is subjected to tests at different rates relative humidity (RH) and at temperatures between 22 and 23 ° C.

Tensile breaking strength (NF T 54 102)

Elongation at break in tension (NF T 54 102)

Water vapor permeability g / dm2 / 24h / 25 microns

x humidités relatives sur les faces du film.

x relative humidity on the faces of the film.

Very weak odor acetic odor Gas permeability cc / dm2 / 24h

Test conditions: 96 hours at 32 ° C in a saturated atmosphere.

In addition, with this film, bags are formed in which animal corpses are enclosed.

The bags and their contents are buried in the ground and periodic checks have shown that the mechanical resistance of the material of the said bags remains satisfactory for 30 to 60 days and that these disappear gradually from 180 days onwards and are completely eliminated after 260 days. .

With the film according to the invention, it is possible to manufacture envelopes intended to serve as a shroud.

Thus, as soon as death has been confirmed by a doctor, the corpse can be introduced into the envelope made in advance and comprising an opening, after which this opening is closed by welding, for example by means of a portable heat sealer available to the doctor, or any other authorized person. The envelope thus tightly encloses the corpse and prevents odors of decomposition from spreading. The body can remain like this for several days without resulting in odor emissions or hygienic difficulties. Indeed, on the one hand, the welding and the material of the envelope are waterproof and on the other hand, the action of the liquid emissions coming from the corpse on the material of the envelope can for example lead to a beginning of destruction of it in a few dozen days.

In particular in the case where the corpse as a result of an illness tends to letter large amounts of gas liable to burst the sealed envelope, it is advantageous to equip it with a valve allowing said gases to escape bubble to bubble. In this case, it is advantageous that said valve is of the type through which a vacuum can be created. Thus, after the opening of the envelope has been welded, a vacuum is created inside it, for example using a simple vacuum cleaner. Such an aspiration makes it possible to delay the decomposition of the corpse since the atmosphere inside the envelope is rarefied. As a result, the exposure time of the corpse in its envelope can then be extended if necessary.

The envelope may be at least partially transparent to allow exposure of the body to family and friends before burial. However, it is advantageous that the envelope is only transparent at the level of the face and is opaque elsewhere, so that the corpse can be enclosed without clothing inside the cover.

In known manner, shortly before the burial, the corpse enclosed in its envelope can be introduced into a coffin. However, thanks to the envelope according to the invention, it is possibly possible to remove said coffin, which is then replaced by said envelope.

The opaque part of this envelope can be decorated and / or colored and / or simulate, for example, clothes. In addition, the envelope can be scented and / or sanitized.

As mentioned above, the film according to the invention can also be used to produce biodegradable coffin basins.

Claims (10)

1 - Polyvinyl alcohol film with delayed aqueous dissolution, obtained from polyvinyl alcohol resin, saponified,
characterized in that its thickness is chosen between 30 and 100 μ and in that the basic polyvinyl alcohol resin contains a proportion by weight of residual vinyl acetate, not saponified, of between 0.2 and 0.7 _% . 2 - Polyvinyl alcohol film according to claim 1, characterized in that it comprises glycerin or a similar body as a plasticizer. 3 - Polyvinyl alcohol film according to claim 1, characterized in that it comprises in its mass at least one anti _- blocking agent. 4 - Polyvinyl alcohol film according to claims 2 and 3,
characterized in that, before removing the water used for the aqueous dissolution, its composition by weight is approximately as follows:

- Water: sufficient quantity for the aqueous dissolution of the resin. 5 - Polyvinyl alcohol film according to claim 4, characterized in that it comprises at least one opacifier in a weight proportion of between 10 and 25%. 6 - A method of manufacturing a film according to any one of claims 1 to 5, wherein continuously mixing all the components, including water, and the aqueous mixture is heated, then spreading said mixture on a grille where it is heated.
characterized in that a polyvinyl alcohol resin is used, the saponification of vinyl acetate of which is such that the proportion by weight of non-saponified residual vinyl acetate is between 0.2% and 0.7%, in that said aqueous mixture, before spreading on the calender, is heated to a temperature between 80 and 95 ° C, and in that a film is produced whose thickness is between 30 and 100 p. 7 - The manufacturing method according to claim 6, characterized in that said aqueous mixture is subjected to deaeration before spreading. 8 - Application of the film according to any one of claims 1 to 5,
characterized in that the said film is used to make shrouds, mortuary covers, coffin bowls, etc., which must have great mechanical resistance for a few tens of days following their contact with the body of a dead being, but be fully biodegraded after a few months of this contact. 9 - Application according to claim 8, in the manufacture of a sealed burial envelope, characterized in that said envelope is provided with a valve allowing gas communications from the inside of the envelope to the outside. 10 - Envelope according to claim 9, characterized in that the valve makes it possible to create a vacuum in said envelope.