CS249130B2 - Method of laminated plate's one-stage production by means of forming and device for application of this method - Google Patents

Abstract

1. Method of manufacturing by moulding in a single pass, a moulded composite panel comprising a base formed from discontinuous glass or rock fibres, impregnated with a polymerized binder and a visible covering sheet, characterised in that an initial component is prepared by impregnation by soaking with a non-polymerized binder so as to obtain an initial component with a binder ratio of approximately 10 to 30% by weight of the total dry extract, at least one layer of fibres bonded with a polymerized binder, obtained by spraying on the fibres, a solution of the non-polymerized binder during the formation of the layer of fibres, followed by the polymerization of the binder, whereby the ratio of the polymerized binder is approximately 2.5% by weight of the layer of bonded fibres, that the initial component is placed on the visible covering sheet and that all the components are pressed accompanied by heating so as to obtain the composite panel by polymerization of the binder and bonding of the components between themselves.

Description

The invention relates to a process for the single-step production of a laminated board by molding, the board comprising a carrier of discontinuous fibers, in particular glass fibers, impregnated with a polymeric binder and a decorative coating, in particular of a temperature sensitive and / or unpolymerized binder. A starting felt blank is prepared from at least one layer of pre-blended discontinuous fibers in which the discontinuous fibers are bonded by a polymerized binder by impregnation by dipping in the binder, then the obtained felt blank is deposited on a decorative coating sheet and the formed assembly is pressed. minimum polymerization duration while heating to 150 to 250 ° C.

BACKGROUND OF THE INVENTION The present invention relates to a process for the single-step production of laminated boards comprising a carrier of discontinuous fibers, in particular glass fibers, impregnated with a polymerized binder and a decorative coating, in particular of a fabric relatively sensitive to elevated temperature and /

Laminated molded panels of this type serve, for example, as interior linings for motor vehicle cabins, where the carrier performs the function of acoustic or thermal insulation, while the decorative coating facing the interior of the vehicle compartment gives the cab an aesthetic appearance.

These panels can also form a decorative lining of a room, while providing it with thermal insulation or adjusting its acoustic properties. The boards can be applied to the walls of the room, or they can form movable elements arranged in the room. In this way, cushions, partitions, screens, blinds or partitions can be formed from laminated boards of this type or from the elements lined with them.

It is known to produce these laminated sheets in a manner in which the individual operations are successive. Thus, a starting felt blank is first formed, which is a non-continuous fiber felt impregnated with a non-polymerizable binder, which is usually a thermosetting resin. To this end, an aqueous composition of the binder is sprayed onto said fibers as they are formed into the shape of a starting felt blank. Thereafter, the laminate carrier is formed by pressing one or more of such starting felt blanks deposited on the. and the felt blank is simultaneously subjected to heat and pressure. During this forming operation, the heat serves to polymerize the binder and to achieve crosslinking or complete polycondensation in the case of a thermosetting resin. A decorative coating sheet is then applied to the semi-solid support; previously, however, the corresponding adhesive composition was sprayed onto the carrier or the decorative coating, or both.

This production has several disadvantages in several consecutive work operations. It requires a number of workstations, resulting in the need for a relatively large workforce. The production line occupies a large space with a large storage area. This type of production is time-consuming and, moreover, the overall line performance is low.

FR 1,289,745 proposes to produce molded laminates in a single manufacturing operation, during which both the binder impregnating layer of discontinuous fibers of the felt blank is cured and, on the other hand, the thermoplastic sheet of the decorative coating is formed. .

The decorative coating sheet softens and molds during heating to the temperature required for polycondensation or crosslinking of said binder, i.e., a binder. to about 200 ° C.

Such a method of manufacturing laminated boards in a single manufacturing operation cannot be used where the decorative coating is a fabric of a temperature-sensitive material required for crosslinking a binder or sensitive to the chemical-physical aggressive effects of the binder. In addition to the effects of temperatures of about 200 ° C for the time required for said polycondensation, i.e., for about 3 minutes, the decorative coating sheet is in diotaque formation with the initial felt blank containing the unpolymerized binder and is thus exposed to said physicochemical effects of the binder. In addition, the method described in said French patent requires the use of a sheet which is impermeable to the binder used and which then creates a barrier to leakage of the binder through the decorative coating sheet. Indeed, when spraying the binder with traditional methods of forming a felt blank, local buildup of the binder can occur as a result of turbulence of the carrier fluid and create local excesses of the binder. This local excess binder could have a permeable decorative coating made, for example, of a fabric, which would result in stains on the free side of the decorative coating.

The above-mentioned drawbacks have no method of single-step production of a laminated board by molding according to the invention, wherein the board comprises a carrier of discontinuous fibers, in particular glass fibers, impregnated with polymerized binder, and decorative coating, in particular fabric sensitive to elevated temperature and / or non-polymeric binder. The method consists in preparing a starting felt blank from at least one layer of pre-compounded discontinuous fibers, whereby the discontinuous fibers are joined by a polymerized binder, preferably present in a small amount, by impregnation by dipping in the binder, whereupon the obtained felt blank is deposited. the decorative coating sheet and the formed assembly are pressed for a minimum polymerization duration while being heated to 150 ° C to 250 ° C.

Preferably, the dipping is carried out by pouring a binder onto a layer of pre-blended discontinuous fibers.

Preferably, a thermosetting resin is used as binder.

Phenoplast resins are preferably used as the thermosetting resin.

The urea-modified jelly is preferably used as the phenoplast resin, the molecular ratio of formaldehyde to phenol being · 2 to 5.

Phenoplast resins with pH are preferably used

1.5 to 3 and 8.5 to 12.

Preferably, a phenoplast resin with a pH of 9.2 is used.

Preferably, a thermoplastic adhesive is inserted between the starting felt and the decorative sheet.

Said thermoplastic adhesive preferably has a grid shape.

Preferably, polyethylene is used as the thermoplastic adhesive.

Preferably, the coating of the impregnated fibers is dried up to a water content of not more than 5% by weight.

Preferably, a sheet of a handling coating is placed on the free side of the precursor.

Preferably, both sides of the laminate plate are heated to different temperatures during the molding.

Preferably, warm air is blown across the starting felt blank.

The invention also relates to an apparatus for carrying out the aforementioned method, comprising a line for impregnating a discontinuous fiber layer by dipping a binder to form an initial felt blanket, wherein the impregnating line of a Obaahuis felt belt to be impregnated is discharged a binder device located above the conveyor and having - at least a width such as the width of the felt belt, a collection tank with a re-assembly system - connects the circulation and an exhaust bell and a suction bell, downstream of the discharge device; The apparatus according to the invention further comprises a single-leg press for forming a starting felt blank and a scorch sheet.

An advantage of the process according to the invention is that the soaking of the discrete fibers in order to obtain the initial felt blank allows for uniform distribution of the binder in the felt blank and avoids its accumulation at certain locations, as is the case with spray binders. This uniform distribution allows the pressing time to be reduced to a minimum duration of polymerization. Not only damage to the scorching coating by heat is eliminated, but also the occurrence of spots resulting from non-polymerization of the binder. Furthermore, the soaking technique known per se and described, for example, in U.S. Pat. No. 2,698,260, allows very precisely the proportional amount of binder contained in the starting felt blank and thus in the finished product, since it allows to control individual soaking parameters such as constrictions. the discharge solution and the impregnation time.

The invention is illustrated in more detail in the following by way of specific examples. The device according to the invention is described with reference to the accompanying drawings, in which:

Fig. 1 shows a device for soaking a layer of discontinuous fibers;

Fig. 2 shows a detail view of the dispensing device; and Fig. 3 shows a forming apparatus for making a laminated plate according to the method of the invention.

The process according to the invention can be carried out continuously. It is possible to carry out - soaking the pre-bonded felt directly after making it and - then use - the obtained preform directly for the forming operation, so that the set of these operations is carried out without intermediate loading. This method also requires several forming stations in order to be able to process all previously formed starting felt blanks.

In order to better adapt the method according to the invention to industrial use, it is possible to realize the invention by using intermediate storage of a preformed felt blank. Since the binder contained in the - felt - blank is completely polymerized, there is no aging of the felt. In addition, the felt blank can be easily compressed during storage.

It is of course also possible to assume intermediate loading of the impregnated starting felt blank.

Soaking is facilitated when a continuous web of pre-bonded felt is applied. In addition, it is also possible to store in the form of coils either a pre-bonded felt or / and an impregnated felt blank.

Heat resins such as phenoplast or amino plastic can be used as a binder for wetting the discontinuous fiber felt. Phenoplast resins, which exhibit good resistance to elevated temperature and humidity, and are moreover inexpensive, are preferably used.

Preferably, the binder for impregnation comprises a phenoplastic resin selected from the group of phenoplastic resins having a pH of 1.5 to -3 and resins with a pH of 8.5-12, the latter being more preferred because the aforementioned resins are acidic. Such resins have a relatively low crosslinking temperature (150-180 ° C) and a relatively short crosslinking time (about 1.5 to 2 minutes) for the thickness and weight of the discontinuous fiber batt used in the present invention. These properties further reduce the risk of damaging the delicate decorative coating during molding. In addition, the use of these resins will reduce energy consumption.

The phenoplast resin is, for example, a urea-modified phenol-formaldehyde resin having, for example, a molecular ratio of formaldshyde to phenol of 2 to 5, and catalysed in an alkaline alkali and alkaline earth metal hydroxide, whereupon the resin is finally neutralized to pH 7 by dilute acid. sulfuric. For resins pH-about 1.5 to 3, this pH is adjusted by adding water and acid to the base 2,491,130

8, but for the resin. pH resin

8.5 to 12 the pH is adjusted by adding water and a base to the resin.

Soaking of discontinuous fibers with binder. This can be accomplished by passing the felt through the bath of the binder. Preferably, the soaking is performed by discharging the binder onto the shifting felt.

By soaking, a starting felt blank containing 10 to 30% by weight of binder based on the total dry matter is obtained. For this purpose, it is possible to use binder compositions with a viscosity close to that of water.

The felt from which the starting felt blank is prepared may be glass fiber felt, basalt fiber, slag fiber, or any other discontinuous fiber that resists forming temperatures. The amount of binder that the felt contains before soaking corresponds, for example, to 2.5% by weight of the felt.

Preferably, a thermoplastic adhesive is deposited between the starting felt blank and the decorative sheet in the form of a film or preferably in the form of a grid. The thermoplastic adhesive improves the adhesion between the initial felt blank and the decorative sheet.

The thermoplastic adhesive may be deposited at the time of assembly of the individual layers forming the laminate plate. It is also possible to pre-assemble the initial felt blank with adhesive to facilitate handling of the assembly.

For this purpose, a thermoplastic adhesive is chosen whose melting point is compatible with the operating conditions of the laminated board production, i.e. the melting point. that is below the forming temperature of the laminate. For example, polyethylene is used.

For example, the decoating coating may be a velvet fabric based material made, for example, of polyamide or polyester.

According to a preferred embodiment of the invention, the soaking of the pre-bonded felt is followed by removing the water by pressure and / or suction and then drying with warm air having for example a temperature of 80 to 100 degrees Celsius and moving at about 10 m / s across the felt. in order to obtain a workpiece containing not more than 5% by weight of residual water, based on the total weight of the felt. Accordingly, the heat supplied during molding is essentially used for the polymerization of the binder contained in the initial felt blank and for bonding the decorative sheet with the felt blank. It goes without saying that the drying described above must not cause premature binding of the binder contained in the starting felt blank.

Advantageously, the laminated board can be formed in a single manufacturing operation, the latter comprising in addition a handling coating facing the wall to be applied, which generally has the function of facilitating the handling of the finished laminated board, stiffening it and avoiding direct contact with the discontinuous felt fibers. The handling coating may be based on a synthetic film, a nonwoven fabric, a metal film, or a laminate film.

The temperature used to form the laminate sheet of the invention is typically less than 180 degrees Celsius on the side of the decorative coating. On the opposite side, the temperature is higher (about 250 [deg.] C.) without the risk of damage to the decorative coating while simultaneously faster polycondensation of the binder resin.

The dipping device shown in FIGS. 1 and 2 comprises a roller conveyor mesh 1 serving as a conveying means for the felt web 3 during its impregnation, on the inlet side of which the felt web 2 drum for impregnation is placed. This felt web 3 already contains about 2.5% by weight of the already polymerized binder. Above the inlet side of the conveyor 1 there is also a dispensing device 4 inepolymerized with a binder, which is continuously fed by the inlet pipe 5 through the inlet pipe 5. The longitudinal axis of the dispensing device 4 is perpendicular to the direction of movement of the felt web 3 and the width of the dispensing device 4 is greater. than the width of the felt web 3 so as to obtain a homogeneous impregnation of the entire thickness of the felt web 3.

The discharge device 4 comprises a horizontal container 6, the front face 7 of which has a lower height than the rear face 8, is extended by an inclined sheet 9 through which the binder 10 carpet flows. The lower end of the inclined metal sheet 9 is located at a distance h equal to approximately 50 mm from the surface of the felt strip 3. Under the front of the conveyor 1 there is a collecting tank 11 for retaining excess drip binder to which the first suction means 12 a fan to remove water from the impregnated felt web 3 and a binder recirculation assembly 13. Downstream of the discharge device 4, an exhaust bell 14 is placed above the conveyor 1 through which the warm air supplied by the duct 15 flows to the impregnated felt belt 3. This warm air passing through the felt belt 3 is sucked in by a suction means, e.g. connected to the suction bell 17 located below the exhaust bell 14 and is then recirculated. On the output side of the conveyor 1 there is a winding device 18 for winding the obtained, felt blank 19 into a coil. At the exit of the impregnation device, the starting felt blank has a water content of not more than 5% by weight. The portion where the water strip 3 is dehumidified has a length of, for example, 0.80 m, while the section where the blown air drying is performed is approximately twice as long. It goes without saying that these lengths depend in particular on the speed of movement of the felt web 3, which is, for example, equal to 2 m / min.

Forming device shown on cib. 3 includes a press 20 comprising a frame 21, a heating upper die plate 22 and a heating lower die plate 23. The upper die plate 22 is mounted on the hydraulic lift 24 and may thus approach in the direction of the arrow F toward the fixed lower die plate 23. delay.

At the entrance to the forming apparatus, a first unrolling device 25 is disposed of a starting felt blank 19 and a second unrolling device 26 for a handling coating 27. A pair of rollers 28, 29 are disposed behind these unrolling apparatuses 28, 29 to assemble the starting felt blank 19 and the handling belt. The third unwinding device 30, feeding the polyethylene grid 31 to said assembly, is located below the assembly and upstream of the assembly table 32 where the assembly is placed in the frame 33, the assembly so arranged being deposited on the decorative coating 34 supplied from the fourth unwinding assembly. a device 35 located below the assembly table 32.

In front of the assembly table 32 there is a cutting device C of the assembly of the initial felt blank 19, the handling coating 27, the polyethylene grid 31 and the decorative coating 34.

It goes without saying that, depending on whether or not the desired article should contain a manipulation strand 27, or whether gluing of the decorative coating 34 to the initial felt blank 19 requires or does not require a polyethylene grid 31, it is possible to crawl all or part of the described device.

In a not shown embodiment of the forming apparatus, the apparatus is provided with additional blowing means and at least one of the plates of the press 20 is provided with openings allowing blowing across all or part of the sheet of the sheet.

Other advantages and features of the invention will be apparent from the following specific examples of embodiments of the method of the invention. The first example is a comparative example. Comparing this example with other exemplary embodiments will show the advantages of the method and apparatus of the invention.

Example 1

A discontinuous fiberglass felt of 1350 g / m @ ² is impregnated during its formation with a binder containing a phenoplastic resin of pH 6-7 by spraying a solution of the binder. Dry the solution to 25% by dilution with water. The phenoplast resin is modified with urea and is prepared in a formaldehyde / phenol molecular ratio of 3 in the presence of barium hydroxide as the catalyst. Upon completion of the impregnation, the resin is neutralized to pH 6-7 by addition of dilute sulfuric acid. The phenoplast resin is modified with urea, which contains about 50%. The starting stock obtained is placed on a sheet of a decorative coating of a daffodil fabric. The assembly is inserted into the press. The compression is carried out so as to obtain a final product having an average thickness of about 6 mm. The pressing time is about 3 minutes, wherein the pressing plate on the side of the initial felt blank is heated to 240 ° C, while the pressing plate on the decorative coating side is heated to 150 ° C. The product obtained has the correct mechanical properties, in particular good stiffness, but shows stains on the side of the decorative coating of the python fabric. These stains are the result of local binder excesses that occur during spray impregnation, as mentioned above.

Example 2

Felt discontinuous pre-connected glass fibers with binders polykoindenzátoivého containing 2.5% by weight and the basis weight of 1350 g / m ² was impregnated with a binder based on fenopliastové resin oi pH 6-7, while using the above-described device ¹ of FIG. 1 and 2. Impregnation is effected by discharging to the felt the binder solution described in Example 1, but diluted by adding water to Obsiah 20% by weight of dry matter. The felt travel speed is 2 m / min. The impregnated starting felt blank is dewatered, then dried by sucking and passing air at a temperature of about 20 ° C at a speed of about 10 m / s until the water content is reduced to 5%. The starting felt blank is then conveyed to the forming apparatus described above, where it is deposited on a sheet of a decorative coating of a team fabric veneer. The assembly is placed in a press. L ^; The sieving is carried out under the same conditions as in Example 1. The product obtained has an average thickness of 6 mm and exhibits the desired mechanical properties. No stain is visible on the side of the fabric decorative coating.

Example 3

The process was carried out under the same conditions as in Example 2, but the pressing time was reduced to 2 minutes. An article of good appearance is obtained but relatively soft due to incomplete polymerization of the resin binder.

Example 4

The procedure was carried out under the same conditions as in Example 3, but using a pH-based phenoplast resin binder. This binder is obtained by -dilution and addition of '•'

12 of sodium hydroxide to the resin of the preceding examples for adjusting the pH to pH

9.2. The product of the desired appearance and stiffness is obtained. Polycondensation is faster than in Example 3 and the 2 minute compression is sufficient to achieve complete or near complete polymerization.

Example 5

The process is carried out under the same conditions as in Example 3, but using a binder based on a phenolic resin of pH 2. This resin is obtained by diluting the phenol-formaldehyde resin of Example 2 and adding sulfuric acid to pH 2. The product is obtained of the desired appearance and stiffness. The binder polymerization is even faster than in Example 3.

Example 6

The process was carried out under the same conditions as in Example 4, except that a polyethylene film was inserted between the fabric decorative coating and the initial felt. The product of the desired appearance and stiffness is obtained. In addition, it is characterized by an extremely strong adhesion between the decorative coating and the felt blank.

Example 7

Working for. under the same conditions as in Example 6, but instead of polyethylene, a polyethylene grid is inserted between the felt blank and the decorative coating. The product has good mechanical and visual properties and high adhesion between decorative pdvlake and felt blank.

Example 8

The process was carried out under the same conditions as in Example 7, except that a nonwoven fabric coating was also deposited on the free side of the felt blank. The product obtained is characterized by good mechanical properties and good appearance, and is also easy to handle.

Claims (15)

OBJECT OF THE INVENTION Method for the single-step production of a laminated board by molding, the board comprising a non-continuous strand, in particular glass fiber, impregnated with a polymerized binder and a decorative coating, in particular of a temperature sensitive and / or unpolymerized binder, characterized in that a starting felt blank of at least one layer of pre-blended discontinuous fibers in which the discontinuous fibers are joined by already polymerized binder but present in a small amount by impregnation with dipping in the binder, then the obtained felt blank is deposited on the decoating sheet and formed assembly is compressed to the minimum duration of the polymerization while heating to a temperature of 150 to 250 ^Q C 2. A method according to claim 1, wherein the dipping is carried out by pouring a binder onto a layer of pre-blended discontinuous fibers. Method according to Claim 1 or 2, characterized in that a thermosetting resin is used as binder. 4. The method of item 3,. characterized in that a phenolic resin is used as the thermosetting resin. 5. A process according to any one of claims 1 to 4, wherein the urea-modified resol type resin is used as the phenoplast resin, wherein the molecular ratio of formaldehyde to phenol is 2 to 5. 6. A method according to claim 4 or claim 5, wherein the phenoplast resin is a phenoplast resin having a pH of 1.5 to 3 and 8.5 to 12. 7. A process according to claim 6, wherein a phenolic resin having a pH of 9.2 is used. 8. A method according to any one of claims 1 to 7, characterized in that a thermoplastic adhesive is inserted between the starting felt blank and the decorative sheet. 9. The method of claim 8, wherein the adhesive is in the form of a grid. 10. A method according to claim 8, wherein the thermoplastic adhesive is polyethylene. 11. Method according to claims 1 to 10, characterized in that after dipping the layer of discontinuous fibers with the binder, the impregnated fiber layer is dried to a water content of not more than 5% by weight. 12. A method according to any one of claims 1 to 11, characterized in that a sheet of handling coating material is placed on the free side of the starting felt blank. Method according to one of Claims 1 to 12, characterized in that both sides of the laminate are heated to different temperatures during the pressing. Method according to one of Claims 1 to 13, characterized in that warm air is blown across the starting material or part thereof during the pressing process. Apparatus for carrying out the method according to Claims 1 to 14, characterized in that it comprises a line for impregnating the felt web (3) by dipping binder to form a blank (19) and a press (20) for single-step forming the obtained blank (19). and a decorative coating sheet (32), wherein the impregnation line comprises a conveyor (1) of a felt web (3) to be impregnated, a binder discharge device (4) positioned above the conveyor (1) and having at least a width such as width a felt belt (3), a collecting tank (11) with a system (13) for re-circulating the binder and the exhaust bell (14) and the suction bell (17), arranged behind the discharge device (4).