FR2676332A1 - Transparent protective coating - Google Patents

Abstract

Device for the preservation, protection and rigorous observation on all the faces of an object. The invention relates to a process which makes it possible to include an object (8) in a volume (27), under vacuum or under gas, the coating (26) of which is a transparent resin of constant thickness e and of excellent optical quality, making possible the use of stereoscopic microscopes. The device according to the invention is particularly intended for scientific bodies concerned with entomological, botanical or mineralogical studies or for universities, the latter demanding an exact reproduction.

Description

 The present invention relates to a device for the conservation and rigorous observation of plants, insects, arachnids, minerals or objects of small sizes, with an exact restitution of shapes and nuances, ensuring complete protection against the aggression of external agents or of possible ohocs. Observation under a stereoscopic microscope is possible.

 A process makes it possible to implant the object in a volume, delimited at its base by an implantation area of very good optical quality, laterally and above by a transparent casing, also chosen or manufactured for optical quality. optimum.

 A perfectly homogeneous resin coating, the thickness of which is constant and the shapes correspond to those of the volume, protects the assembly.

 The possibility of creating a vacuum is provided using a vacuum device, this in the coated volume. It should be noted that vacuuming is only to be carried out if the nature of the object requires it.

 This type of device currently exists, but the objects are immersed in a block of resin during polymerization.

These full inclusions cause defects, on the one hand physical
and chemical, on the other hand optical.

Chemical faults: The catalyst produces a chemical reaction
results in the polymerization of the resin. This reaction is very bad for organic colors, especially in entomology
and in botany. Surface structures can, depending on their com
-position, to be attacked, always by this chemical reaction. Of
cracks or crackles often mark certain chitins, in
insects or arachnids. A dissolution of the materials forming the surface
plants and even insects is not uncommon. This has the consequence
tarnish the transparency of the resin.

The heat produced by the catalyst can
- also blacken the wings of certain butterflies, especially in
Morphids. This phenomenon prohibits its inclusion.

Physical defects: The retraction of the resin during poly
-merisation causes a deformation of the soft parts of the object in
causing bubbles to appear around it. These bubbles remain
trapped in the resin once polymerized. This phenomenon is very
frequent in entomology.

Optical defects: The resin blocks being geometrical shapes
very often completely different from that of the object, the thickness of the resin is irregular, implying significant defects in refraction and magnifying glass effect. These optical deformations prohibit rigorous observation.

 The resin being in contact with the surface.

of the object, it is impossible to distinguish its matt or shiny parts - this, because of the varnishing effect.

 These defects due to the very principle of full inclusion, imply poor restitution of shapes, colors, nuances of brilliance and appearance. In some cases, objects cannot be included, particularly in entomology, because of their sensitivity to heat.

 This type of inclusions cannot be used for scientific purposes, these requiring perfect restitution, either for study or for educational purposes.

 The creation of a volume, in which is installed 11 element to be observed -ver, avoids any chemical and physical contact with the resin during polymerization. There is therefore no degradation, and the inc -lus element does not require any particular precaution.

 The shapes, colors, nuances of gloss and appearance of the surfaces are fully and exactly restored.

 The base of this volume, which is the useful surface for the implantation of the element, is catalyzed in an oven. I1 follows a perfectly flat implantation area, similar to glass, without orientation, that is to say isotropic.

 The excellent surface quality and isotropy imply optical qualities superior to ordinary glass.

 The side and upper walls of the volume are delimited by a transparent casing, chosen or manufactured to have optimal optical qualities.

 The surface which surrounds the implantation area is first not steamed, then secondly, after the second pouring, is steamed. Installation of the transparent casing takes place at the edge of the dtimp- -lantation area, on this framing surface which is then in the gelatinous state.

 During the last pouring, the framing surface must be gelatinous.

 This last casting completes the coating of resin around the volume.

Under the effect of the catalyst of the freshly poured resin, the polymerization is transmitted chemically to the gelatinous volume of the encircling surface.

 The coating is then catalyzed in an oven, implying a homogeneous flatness and isotropy.

 The thickness of the volume coating is identical at all points.

 A storage period is compulsory for at least twelve hours in order to perfect the flatness of the base of the coating. In fact, during> polymerization, a slight shrinkage phenomenon, between the assembly-the coating and the volume located under the implantation area, causes a curvature of the base of the coating. This curvature is con-convex and makes up very well if the storage is done well flat and level, when the assembly finishes catalyzing.

 This retraction is due to the different polymerization states of the entire coating.

 The effects of refraction and magnifying glass are completely eliminated thanks to transparency and flatness.

 A vacuum device is provided if necessary. This device is composed of a tube in which is placed a bilge valve. This same device makes it possible to put a gas in the volume. To do this, simply reverse the valve.

 The conservation problem is thus resolved.

 The finished product is therefore in the form of a volume under vacuum (or with a gas) coated with resin, the contours of which follow the shape of said volume, therefore of constant thickness.

 It is an inclusion in volume.

The accompanying drawings illustrate the invention:
Figure I shows the preparation of the mold (2) and the marking of the mark (I) defining the level of the first casting.

 Figure 2 shows the terphane sheet (3) with its reinforcement (4), the folded ends of which form the tongues (5).

 FIG. 3 represents the ratios of the dimensions to be observed.

 Figure 4 shows the ready-to-pour resin (6), poured into the mold (2) up to the mark (I).

 Figure 5 shows the sole (7) in the mold (2).

 Figure 6 shows how to place the terphane (3) with its reinforcements (4) and tabs (5).

 Figure 7 shows the terphane (3), steaming the surface (I0) and its volume (13), fixed by the tabs (5) to the edges of the mold (2).

This figure shows the surface (9) not steamed and the corresponding volume (I2).

 Figure 8 explains how to take off the terphane (3), using the tabs (5). The installation area (IO) and the framing surface (9) are also shown.

 FIG. 9 shows the sole (7) in the mold (2) with its framing surface (9) and its implantation area (in).

 Figure 10 shows the placement of the element to be included (8) on the installation area (in).

 Figure II shows the element (8) fixed on the implantation area (Io).

 Figure I2 represents the transparent casing (II).

 Figure I3 shows a section of the vacuum device (I4) and its components, the pellets (I6) and their orifices (I7), the spring (I8), the ball (I9) and the tube (I5).

 Figure I4 shows the dimensions of the device (I4).

 FIG. 15 represents the positioning of the device (I4) in the hole (20) of the transparent casing (II).

 Figure I6 shows the device (I4) attached to the transparent casing li (il) to use it in vacuum. The pad (î6), located outside, receives the spring (I8). The useful dimensions are given.

 Figure I7 shows the same elements as in Figure I6, but in the case where the device (I4) is used to put gas.

The tablet (I6) located outside, receives the ball (19).

 Figure I8 shows the device (I4) fixed to the transparent casing (II), sealed by a resin gasket (21) and by the installation of a terphane plug (22) on the orifice (I7) of the tablet (16).

 Figure 19 shows the edge (23) of the transparent casing (II), provided with the device (I4), on which a net of resin is placed.

Figure 20 shows the transparent casing (II) ready to be put in place. Also shown are the device (I4) with the plug (22)
FIG. 21 shows the positioning of the transparent casing (II) at the edge of the implantation area (in), on the gelatinous part of the framing surface (9). The device (I4) is shown.

 FIG. 22 represents the transparent casing (îî) welded to the framing surface (9) by the processing of the edges (23).

 Figure 23 shows the ready-to-pour resin (6) poured into the center.

- be from the mold (2) on the transparent casing (II).

 Figure 24 shows the different volumes and surfaces formed by rif the different stages of polymerization. The liquid resin (6), the gelatinous resin (I2), the semi-solid resin (13).

 Figure 25 shows how to place the terphane (24) on the surface of the liquid resin (6), for steaming.

 Figure 26 shows the terphane (24) correctly placed and the glass-glass (25) which must be placed on the terphane (24) to obtain a perfect flatness of the surfaces. The marks fl and fa indicate the boundaries between the different catalysis states, which will be homogenized during the final catalysis in an oven.

 Figure 27 shows the coating (26) perfectly homogeneous, at the end of catalysis in an oven with terphane (24) and glass (25).

 Figure 28 shows the takeoff of the terphane (24).

 FIG. 29 represents the demolding of the coating (26) by peeling off the walls of the mold (2).

 Figure 30 shows the inclusion in volume with the element inc -lus (8); the volume included (27); the coating (26); the device (14).

The planar and level surface (29) is shown.

 Figure 31 shows the concave base (28). The design is intentionally overdone. The flat and level surface (29) makes it possible to remedy this defect.

 Figure 32 shows the release of the plug (22).

 Figure 33 shows the evacuation of the volume (27) by a vacuum pump (30) whose tip (3I) is introduced into the orifice (I7) of the pellet (I6). The ball (I9) and the spring (18) are shown in the suction position.

 Figure 34 shows the finished product. It should be noted that, depending on the case, chamfering can be carried out.

 The embodiment which follows requires working on a flat and level surface. This is due to the fact that the resin is liquid like water.

 The careful preparation of the various elements used to carry out the process is very important. The cleaning of the molds and terphane sheets used for drying is essential as well as a rational organization, in order to allow a chronology in the der; - flow of the realization.

The main operations to stenchainer are as follows
First roll: Manufacture of the sole (7) with its implantation area (IO) and its framing surface (9).

Installation of the element to be included (8)
Preparation of the transparent casing (II) and of the vacuum or gas evacuation device (14). Installation and bonding.

 Last pouring s Manufacture of the coating.

 Unmolding and compulsory storage: Flatness of the ltenro -bage base.

 Machining s Vacuum or gas, chamfering, polishing.

 The first casting is used to manufacture the sole (7) on which there is the framing surface (9) and the implantation area (IO).

Plates I to 3, Figures I to 9-
Preparation of the mold (2) and tracing of the mark (I) defining the level of the first casting: Figure I.

 The mold (2) must be clean and without scratches.

 This is made of terphane of 350 / u r reinforced as needed. The terphane used is preferably transparent to allow rigorous control of the polymerization steps. If the reinforcements must be glued, the glue must in no case have contact with the resin, because it is based on cyanolite.

 The mark (I) is placed outside the mold (2) using a tracing point. This mark must be seen inside.

 The height of the mark (I) corresponds to the height of the first run. The height is measured from the base of the mold (2). The value of the measurement is defined according to two criteria for using the product. The observation is made without a stereoscopic microscope, the height is chosen in a slot between 5 mm. and 8mm.

 The observation is made with a stereoscopic microscope, the height is chosen in a slot between 4mm. and 5mm.

 The dimensions of the mold depend on the one hand on the characteristics of the element to be included and on the other hand, on the customer's requirements, particularly in entomology, where storage problems tend to standardize the sizes.

 Preparation of the terphane sheet (3), its reinforcement (4) and its tabs (5): Figure 2.

 The terphane sheet (3) must be clean and without scratches.

 This is made of I75 terphane and is reinforced by a strip, also of I75 terphane> 4, (4) glued to the outer surface of the terphane sheet (3).

 The ends of the reinforcement (4) are folded so as to make lan -guettes of fixing (5). Always to properly monitor the polymerization, the assembly must be transparent.

 The height resulting from folding is defined in the following paragraph.

 Rules concerning the dimensions to be observed s Figure 3.

The dimensions of the mold (2) are characterized by rectan -gular or square shapes. defined by length L: width 1: height is height h; the height of the mark (I) h2. These dimensions defined in advance, as previously explained
The dimensions of the terphane sheet (3) are characterized by rectangular or square shapes, defined by the length LI; the width 1I. These dimensions are deducted according to the value of h2 (which is equal to the thickness e.) And correspond to the equalities
LI = L - 2 (e). lI = l - 2 (e).

 The dimensions of the reinforcement (4) and of its ends (5) are characterized by the shape of a rectangular strip, defined by a length equal to L + 60mm., A width of 10 mm. The glued length is equal to LI - IOmm. (To avoid contact with the resin.).

The bending of the ends (5) must define a height hI. This height hi responds to equality
hI = h - h2.

 Note: Very rarely, the terphane sheet (3) is circular. The diameter d corresponds to equality: = = L - 2 (e).

 The mold is generally square in this case.

Resin preparation t
The transparent resin is of the unsaturated, orthophyll-polyester type, the crosslinking agent of which is methyl methacrylite. If possible, order the resin with the minimum accelerator.

 The accelerator, Cobalt Octoate, is measured in accordance with the manufacturer's instructions and the climatic conditions. The wetter the weather, the faster it should be accelerated to facilitate the action of the catalyst. Do not exceed the maximum dose prescribed by the manufacturer in order not to alter the transparency.

 The dosage of the styrene monomer is carried out in a proportion of 5 to 7%, according to the manufacturer's instructions. The purpose of this monomer is to make the resin more fluid, therefore easier to work with, especially to combat the formation of bubbles.

 The metering of the catalyst, the methyl peroxide peroxide is also carried out according to the manufacturer's prescriptions, but taking into account three criteria: The relative humidity rate, the atmospheric pressure, the polymerization time, ie indirectly the retraction. This dosage is the same for the second pour. The material of the transparent casing is therefore very important, because the physical characteristics depend on it. For glass, the dosage must be made to a minimum, to avoid breakage. For plastic, the dosage depends on the thickness of the plastic. In fact, plastic fears more deformation than breakage. For resin, the dosage can be high, because the walls are thick and flexible. Cases of deformation are very rare. Note that curves may be provided by some manufacturers.

 The mixing carried out after each dosage must be careful and regular. Always turn in the same direction, without hitting the edges and edges of the tank, to avoid the formation of bubbles or 1 'dust. After dosing the styrene monomer, leave to stand for approximately 10 minutes. before dosing the catalyst.

 Pouring the liquid resin (6) into the mold (2) up to the mark (I): Figure 4.

 The pouring of the ready-to-pour resin takes place regularly in the middle of the mold (2) up to the mark (I). This is to prevent the formation of bubbles.

 A check allows cleaning if necessary. The cleaning is carried out using a needle.

 Checking the thickness of the sole (7): Figure 5.

 Check the value of h2 carefully with the mark (I) before continuing.

 How to install the terphane (3), its reinforcement (4) and its tabs (5): Figure 6.

 In order to expel the air, the terphane sheet (3) is curved, placed in the center, then brought into contact with the resin which is liquid (6).

 The edges are gradually released so as to reduce the curve to flatness.

 Positioning of the tongues (5) on the edges of the mold (2): Fig -re 7.

 The ends of the tongues (5) are hooked to the edges of the mold (2) to hold the sheet of terphane (3) correctly on the surface to be steamed (IO). The reinforcement (4) ensures rigidity.

 The polymerizations of volumes (I2) and (I3): Figure 7.

 The polymerization of the surface (IO) and its volume (I3) is carried out by catalysis in an oven. The parboiled surface under the terphane sheet (3) is called: Area of implantation (IO). The corresponding volume is called Steamed volume (13).

 The oven causes a rise in temperature involving three effects: An intense retraction causing a push from the center of the parboiled volume (I3) going down and up. The base of the mold (2) and the terphane sheet (3) retain this thrust.

 This thrust causes a flatness offering an excellent surface quality, equivalent to ordinary glass.

 There is no orientation, so the physical properties are the same in all directions. We have an isotropy giving a very good refractive index. This index is of the order of Ils49 for = 587.6 nm. helium.

 Transparency is therefore improved and is of the order of 92%.

 It should be noted that the steamed volume (I3) and the implantation area (IO) are of optical quality superior to glass.

The polymerization of the surface (9) and its volume (I2) is carried out in the open air. The surface catalyzed in the open air is called
Framing surface (9). The corresponding volume is called t Framing volume (I2).

 Polymerization in the open air is slow. The resin remains in the gelatinous state for a long time.

 Peeling off the terphane sheet (3) t Figure 8.

 the hardness of the implantation area (IO) is tested using a needle passed under the edges of the terphane sheet (3). When the implantation area is hard, pull the tabs (5) and peel off the sheet of terphane (3). The implantation area (IO) must be perfectly flat.

 Insole control (7): Figure 9.

 The condition of the surfaces is checked: The framing surface (9) must be gelatinous.

 The installation area (IO) must be flat and perfectly clean.

 The placement of the object to be included (8) on the implantation area (in).

 Plate 4, figures IOII and I2.

 The element to be included must be anhydrous. It is placed on the implantation area (IO): Figure IO.

 The element to be included (8) can be glued by point of resin or wedged by the transparent casing (II): Figures II and 12.

 your installation and bonding of the transparent casing (II) with its vacuum or gas evacuation device (14).

 Plates 5 to 7, Figures 13 to 22.

Preparation of the transparent casing (II): The transparent casing can be made of plastic of the polycarbonate type, glass or resin, in the latter case, the catalysis must be carried out in an oven. In all cases the optical quality must be optimal. If a vacuum or
u under gas is planned, drill the casing to be able to put the device (14).

 Checking the vacuum or gas device: Figure 13.

 The device (I4) comprises a tube (I5) into which is inserted a spring (I8) and a ball (in), compressed between two pellets (I6) each pierced by an identical hole (I7). The control consists in veri -fier that the ball (I9) makes good sealing when it is in abutment on the orifice (I7) of the disc (I6) Dissension6 of the device (14):: Figuré 14.

The dimensions of the device (I4) are characterized by the length
L2 = IO mm. and the diameter d = 5 mm. This device (I4) is made of resin, except for the ball (I9) and the spring (I8). This set is transparent.

 Installation of the device (I4) for a vacuum: Figures 15 and I6.

 The device (I4) is introduced into the hole (20) of the transparent housing (II): Figure I5.

 The pad (I6) which is outside of the volume of the transparent housing (II) must retain the spring (I8).

We then adjust the length eI which must exceed
r walls of the transparent cater (II). This length eI is equal to the difference of the thickness of the sole (7), FIG. 9, by the thickness of the walls e2 of the transparent casing (II) and FIG. 16.

eI = e - e2
Installation of the device (I4) for gas firing: Figures I5 and 17.

 Same procedure as above: Figure I5.

 The pad (I6) which is outside the volume of the transparent housing (II) must retain the ball (19).

The adjustment is made in the same way as in the previous case:
Figure I7.

 Installation of a seal between the device (I4) and the walls of the transparent casing (II): Figure I8.

 When the length eI is properly adjusted, a tight seal is placed between the walls of the transparent casing and the device (I4).

 This joint is made with highly catalyzed resin.

 There is a resin bead (21) around the entry of the device (I4) in the transparent casing (II).

 Installation of a terphane plug (22) in front of the orifice (I7) of the patch (I6): Figure I8.

To plug the orifice (I7), we use terphane from I2. This piece of terphane is bonded to the gelatinous resin on the pellet (I6)
The resin and terphane assembly form the plug (22), intended to prevent the liquid resin from the second pour from entering the device (I4).

 Preparation of the slices (23) of the transparent casing (II): Figure 19.

 A light layer of resin is placed on the edges (23), using a brush. This resin is also highly catalyzed.

 Checking the housing before installation: Figure 20.

 The resin gasket (21) and the plug (22) of the device (I4) are checked.

 Installation of the transparent casing (II), fitted with its device (I4): Figure 21.

 The transparent casing (iî) is placed in the mold (2), while monitoring that the device (I4) is properly adjusted. If necessary adjust it.

 Installation of the transparent casing (II) on the edges between the gelatinous surface (9) and the implantation area (IO) t Figure 22.

 Once the transparent casing (II) is well placed, a slight pressure is exerted on it to ensure a chemical reaction between the gelatinous resin on the framing surface (9) and the fresh resin -ment deposited on the edge (23). This reaction ensures sealing.

 Always check the installation of the device (I4). Readjust it if necessary.

 Leave to catalyze for approximately 40 min., Then carry out a leak-tightness test by delicately handling from left to right the transparent housing (II). If it does not move, sealing is ensured.

 The set is ready for the last pour.

 The last pour serves to complete the coating (26).

 Plate 8 and 9, figures 23 to 28.

 Preparation of the resin: It is carried out in the same way as for the first casting.

Pouring the ready-to-pour resin (6) into the mold (2): Figure 23
This operation takes place in the same way cue for the first casting. We pour to the edge of the mold (2).

 Resin layer states t Figure 24.

There are three distinct states of resin: The resin (6), just poured, which is liquid and slightly greenish. t-
The resin (I2), of the framing volume, which is gelatinous and cloudy.

 The resin (I3), of the parboiled volume, which is transparent and practically solid.

 Laying the terphane sheet (24) to steam the whole: Figu -re 25.

 The terphane sheet (24) must be clean and without scratches.

 It is cut from a 175 terphane sheet. There is no reinforcement. The dimensions of the terphane sheet are characterized by its length, which is equal to that of the mold plus 20 mm. , and its width, which is also equal to that of the mold plus 20 mm.

 The installation is carried out in the same way as for the first casting.

 The terphane sheet (24) rests on the resin and on the edges of the mold (2).

 Place glass (25) on the terphane sheet (24): Figure 26.

 The installation of the glass makes it possible to obtain a perfect flatness of the upper surface of the coating.

 The marks f and f represent the boundaries between the resin states. f is the limit between the liquid resin and the gelatinous resin and f is the limit between the gelatinous resin and the semi-solid resin.

 Control of coating polymerization (26) s Figure 27.

 The chemical exchanges take place at points f and f. Homogeneity takes place gradually.

 When the coating is homogeneous, the glass is removed to see if the terphane sheet (24) comes off on its own. When the sheet (24) peels off in this way, it can be peeled off.

 Takeoff of the terphane sheet (24): Figure 28.

 We proceed in the same way as for the first casting.

 Demoulding and compulsory storage serve to perfect the surfaces of the coating (26).

 Plate IO figures 29 to 31.

 Unmolding the coating: Figure 29.

 We take off the edges of the mold (2). The coating (26) is released.

 Storage of the inclusion on a flat and level surface: Figure 30.

 The inclusion then consists of the coating (26), its volume (27) and the element to be observed (8). The device (I4) is visible and the hole (I7) is still plugged. The surfaces are hard, but the interior volumes continue to catalyze.

 Catching up the base (28) of the coating (26): Figure 31.

 The inclusion is placed on a flat and level surface (29) to make up for the slight convex curvature of the base (28). This curvature is due to the effects of retraction during the homogeneity of the states of the resin during catalysis in an oven.

 The defect disappears after a dozen hours.

 Machining. Plate II, figures 32 to 34.

 Vacuuming: Figures 32 and 33.

 The plug of terphane (22) is removed. To do this, scrape the pastil (I6) using a curved histological needle, and release the orifice (17). Check that nothing is blocking the mechanism. Figure 32.

 Vacuuming is carried out by inserting the end piece (31) into the hole (17). After adjusting the vacuum pump (32), suction can take place. Air flows from the volume (27). Figure 33.

 Machining: It consists of cleaning the orifice after placing it under vacuum. The end piece (31) can damage the edges of the orifice (I7), impolite -quant a small chamfering, followed by a polishing.

 If necessary, chamfering of the edges is carried out with polishing.

 The finished product is called a volume inclusion, and is composed of a coating (26), perfectly homogeneous, of optical quality superior to ordinary glass, of a volume under vacuum or under gas (27). The device (I4) seems to be embedded in the coating (26). The included element (8) is in excellent storage conditions. It can be observed with rigor, with the naked eye or using optical instruments such as the stereoscopic microscope, the restitution being perfect. Protection is ensured against external agents and possible shocks, thanks to the coating (26). Figure 34.

 Its application is particularly suitable for scientific organizations (O.R.S.T.O.M. ect ...) or universities, in biology.

 Entomological, botanical and mineralogical services do not currently have such a comprehensive system. It should be noted that gas firing is possible. This device is comparable to the lamel - the ones prepared for microscopes, any proportion kept, but the quality of observation is identical on all sides.

Claims (4)

I) Device for preserving, protecting and restoring the shapes, colors and nuances of brightness of an element to be observed or studied, of entomological, botanical, mineral or metallic origin, characterized by a coating of transparent parallelipipedic resin (26), whose volume (27) is of the same shape and contains the object to be observed or studied. 2) Device according to claim I, characterized by the volume (27) delimited above and laterally by a transparent casing (îi), of excellent optical quality, and at its base by the implantation area (IO), also of quality excellent optics. 3) Device according to claims I and 2, characterized by a thickness "e". of the coating (26) constant at all points. 4) Device according to the preceding claims, characterized by a vacuum or gas volume (27), provided by the device (I4>