ES2284454T3 - PLASTERBOARD. - Google Patents

Abstract

A lining paper to be used in the manufacture of plasterboard is given a surface finish by printing the liner before it is used in plasterboard manufacture. The resulting plasterboard has the printed-on surface material on the whole of one face of the board, with a density of print sufficient that under optical examination at least 80% of the surface of the lining paper is covered by the applied print. The printed surface may be coloured to match the colour of a jointing material used to fill joints between adjoining boards after they have been secured in place.

Description

Plasterboard.

This invention relates to the manufacture of gypsum boards (also known in the United States as boards cast). Gypsum boards are well known for use in the formation of ceilings and interior wall surfaces in buildings In general, the front face and the edge surface side of the plasterboard are provided with a coating of multi-band paper called plasterboard siding,  while the reverse side is coated with a second paper Coating. Both of these coatings are papers of multiple bands

A procedure for using plasterboard has been hold the plasterboard in position and then cover your face exposed and the joints between sheets of plasterboard with a thin "rubber layer" of wet plaster. After it has been Hardened, requires decoration with paint or wallpaper.

Another procedure for using plasterboard has It has been widely used and dispenses with the "rubber layer". Gypsum board is manufactured using a lining paper plasterboard that has a light color. This is used to form the front surface and the side edge surfaces. The lateral edges of the plates are shaped to form a cavity at its edges in contact. After holding the plates in position, their edges in contact are joined with tape and a bonding compound that is applied in the cavity above the tape joining to create a continuous flat wall surface, with visible joints at regular intervals.

Then the wall is decorated with wallpaper or well with multiple layers of paint, which serves, among others things, to hide the boards. If paint is used, what normally required is a first "thin layer" or primer, followed by two additional full layers. This It requires painters to go to the wall three times.

There have been several proposals for manufacturing of plasterboard with a decorative finish applied during the manufacturing, before fixing the plates in position. Examples of such proposals include US patents 3507684, 3694298 and 3984596.

US Patent 4579610 proposed a process in which the surface of a plate coating paper of Plaster is taxed with a base layer of clear or tinted latex. He Engraving process applies this material as a dot pattern, so that the applied material does not seal the paper. The paper of Base is then overprinted with a decorative design. The dimensions for the engraved pattern are not exemplified, but it is it is possible that the points of an engraving pattern can cover 50% or less of the total area to which the pattern applies.

The subsequent application of a decorative design it is not described in detail although it is said that a spots pattern.

The indications that can be understood from of this document is that the surface of the paper remains exposed between engraving points, to maintain the porosity of the paper. He subsequently applied pattern should be such that it retains the porosity.

Something more recently, EP-A-521804 has described a plate of plaster made using a coating paper with a layer applied to the lining paper before the plates are manufactured. The document recognizes that this can prevent contrast between plate color and material color used to form joints between the plates. The owners of this document are manufacturing pre-decorated plates and a compound Matching color union. In this document, as in proposals above for a predecorated plate, there is recognition that the application of a decorative layer to the plating of plaster could produce an unwanted reduction in permeability of the lining paper and thus prevent the exit of steam during drying of the plaster.

It has been found that the lining paper Preset and plasterboard can be manufactured by printing the lining paper before being used in the manufacture of the plate also does not need to use a printing process apply a pattern of separate points with spaces between they.

According to a first aspect of this invention, a precoated plasterboard is provided that has paper of coating on its surfaces with a material printed on the same on a whole face of the plate, with a print density on the lining paper enough so that under an exam optical at least 80% of the paper surface of Coating is covered by applied printing. The impression  applied can extend over the contiguous edges of the license plate.

The material that is applied by printing will include usually a color to match the color of the plate with the color of a binding compound that will be used to bond the plate edges. The applied material may also include lacquer colorless or colored, for example to increase the durability of the printed surface

It would be within the scope of the invention apply only a colorless lacquer to improve durability, but it is preferred to include a color application.

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The printed material can be a continuous layer of applied printing. Alternatively it could be provided as engraving points superimposed on each other and between them covering 80% or more of the total surface area.

The determination of the degree of coverage Superficial is done by a visual exam using a magnifying glass or a microscope with an increase not greater than 100. We have discovered that printing areas that appear to be continuous in This extension is not completely continuous if observed under a electron microscope powered to provide something that approximate the largest increase that can be achieved with said instrument. It is believed that these discontinuities that may observed only in said high detail resolution are pores through ink (instead of unprinted areas) and ignored when it is determined whether the printed material covers 80% or more of the Superficial area.

In a second aspect of this invention, provides a procedure to manufacture a pre-plasterboard which comprises the stages of:

print on a surface of a band of lining paper

introduce wet plaster between the surface opposite of said web of liner paper and a second Coating paper band, conform the edge areas of said first band around the plaster to form the edges of the plate, cut into sections and heat to dry the plaster, thus forming a plasterboard with printing on an exposed face,

characterized by the fact that printing in the first band of the lining paper is spread over such a width that the entire face of the plasterboard has an impression on it, with a sufficient print density so that under an optical examination at least 80% of the paper surface Coating is covered by applied printing.

The stages of introducing wet plaster between two Coating paper bands, forming edge areas, cut into sections and dry the plates will all be done generally conventionally in automated machinery.

The coating paper strip that receives the print will generally have a width slightly larger than the width of the plasterboard to be manufactured, so you can cover one side and two edges of the plates and also wrap around on the margins of the reverse face where it will be superimposed by the second band.

Printing is preferably applied throughout the width of a surface of a strip of the coating paper  and consequently the resulting plasterboard has the color printed completely covering the face of the plate, two edges opposite of the plate and the margins of the reverse face.

Alternatively, the edge areas of the band that form the edges of the plate and wrap around on the reverse side can be left unprinted. For a good aspect is preferable that the printed color extends from the face exposed on at least part of each edge.

It is intended that predecorated plates can be used to form ceilings, interior separations or faces interiors of the wall by attaching them to a support structure, by example by nailing or screwing them to the structure so conventional, or using hidden fasteners.

The plates can be of conventional size. Plates for use in the manufacture of walls and ceilings can have a length that exceeds 2 meters and a width that exceeds 70 centimeters, being often greater than 1 meter. They can smaller plates, such as ceiling plates, be used, supported by a grid structure that is suspended by herself from above.

When the plates are fixed in position, by example by screwing or nailing the structure, the joints between the plates can then be filled with a binding compound and this will also be used to cover the screw heads, nails or other exposed fasteners.

Conveniently, the material printed on the plates should provide them with a color that matches the color of the binding compound. Consequently, the joints in the wall or the Roof are much less visible.

Accordingly, the invention includes a combination of

i)

predecorated plates as has defined above; Y

ii)

a binding compound to fill the joints between the plates after fixing,

where the surface material printed on the lining paper matches the color of the compound Union.

The material that is printed is expected to be a uniform color that matches the color of the binding compound. However, it would be within the scope of this invention to print a design on the plates or a random pattern, especially if this could be done for example to camouflage the joints between the plates.

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The invention can be used to provide plates that match the color of the bonding compound, so that the finished wall has a single color (or possibly a pattern) in which the joints are combined with the wall and not necessary a subsequent decoration.

Another possibility is to arrange a wall that paint after the plasterboard has been fastened in position and mounted, but that requires a few layers of painting.

Therefore, the invention includes a procedure to make the surface of a space setting gypsum board as specified above, filling joints between them with a mobile composition that is allowed to harden later, and applying no more than two coats of paint as single decorative treatment before the occupation of the place. The invention also includes the use of said plasterboard and a hardenable and mobile joint composition for the manufacture of said surface of the place.

The printing of the material can be done directly on the paper liner before the Coating is used in the manufacture of the plasterboard. Be preferably applied by a printing process that applies a continuous layer of ink to the substrate being printed. A particularly anticipated process is by printing flexographic The flexographic process is widely used to print on a fiber plate for boxes, paper for bags of paper, and other packaging materials. In that application the printing is applied to the paper or plate from, for example, a stereo or a molded print roller that is formed using a polymeric material and that is symmetrical of the design or denomination It is printing.

Continuous printing throughout a band (unlike printing a repeat image) is a technique that is already available in the printing industry. For print substantially across the entire width of a band, you can use a normal flexographic printing machine, but the roller that would normally carry a stereo is provided however of a continuous surface of polymer material or can use a printing roller with a smooth surface.

If the continuous surface is provided with a flexible sheet of polymeric material wrapped around a roller, the edges of the sheet that extend along a Roller circumference are joined together.

Suppliers of casings, stereos and molded rollers for printing include Regal Rubber , Miller Graphics , Design and Stereo Services and Strachan & Henshaw machinery.

Printing could be done by other means printing process, as long as the result is to apply the 80% printing of the surface to which the Print. To control the color of the coating paper It is desirable that the coverage be even greater, such as by at least 90% or at least 95% of the area.

Printing through an engraving process in more than one printing station it would be a way to cover a high proportion of the total area: the engraving points applied in a printing station could largely fill the spaces existing between the points applied in another, but also It would produce an overlap of points.

Whatever technique is used, it is Probably the weight of the solids applied, including resin binder, range between 7 and 30 g / m2.

Flexography or other printing can be done using inks with an aqueous base or using inks with a organic solvent base in which pigment is dispersed. Be generally prefers to use an aqueous base and thus avoid using of flammable organic solvent. We have found that for the present invention aqueous based inks can be used. Is probably a water-based ink appropriate for use in the present invention contains pigment, water and materials binders It is likely that the binder materials are synthetic polymers such as acrylic resins.

Even with flexographic printing we prefer print on more than one print station to get a combination of properties

The first impression is desirably made using a colored ink. This may contain well more than one 40% by weight pigment, as well as a binder, water and minor ingredients It is likely that the pigment constitutes more than 50% of the total solids in the ink.

A top print layer can contain a much smaller or even zero pigment ratio, for example, 0 to 25% solids content, with a higher proportion of binder resin. This layer can serve as lacquer, providing better resistance to marking during handling and abrasion after humidification. The latter is valuable for provide a "clean and clean" or washable surface.

It is normal practice for ink manufacturing have it done by a specialist ink manufacturer that can work better in close cooperation with a company that has facilities for manufacturing and printing paper. The formulation of the ink to provide a required color is part of the normal skill of the ink manufacturer.

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A series of numerical scales has been proposed For color definition. One that is commonly used is the CIE Lab color space in which a "L" parameter indicates clarity, a "a" parameter indicates color on a numerical scale which ranges from green to red and a third parameter "b" Indicates color on a scale that ranges from blue to yellow. A positive value for "a" is red, a positive value for "b" is yellow.

The lining paper on which it Apply the printed color can be done in a conventional manner using the normal machinery used to make paper and multi-layer plates through a wet process. Fibers used in the manufacture of the layers of the coating paper They can be new or recycled or a mixture of both.

For the top layer it may be desirable use fibers that have been discolored or discolored so incomplete (called semi-discolored fibers) of so that the top layer has a light color before Apply printing. Alternatively, it may be preferable. use a printed color density that can mask a darker color of the lining paper. May be preferable that the fibers of the upper layer are predominantly fibers chemical and therefore without lignin to prevent yellowing. Without However, we have found that if a colored print is applied, the invention can be carried out using a top layer formed by a predominance of semi-chemical and / or mechanical fibers that retain some or all of the natural lignin content of wood original. The use of such fibers is based on the color printed for stabilize the color of the paper, both because of its own color as for the protection of the upper layer of sunlight from such so that yellowing of the fibers that are avoided or delayed is avoided They contain lignin in the top layer.

The top layer could be made from pulp - that is, new fibers. However, for reasons of Economy will usually be done from recycled fibers, complemented if necessary by new fibers.

Waste paper to provide the fibers Recycled will generally be selected to give a nuance light whitish An appropriate origin includes newspaper Unprinted, lightly printed and so-called cuts - en that is, pieces of paper that are made using pulp mechanics.

If desired, under the top layer there may be also a second layer that has a higher proportion of fibers discolored and possibly of layer-like composition higher. The rest of the layers form the inner and reverse face of the lining paper It is normal that these contain a large proportion of non-discolored fibers which can be fibers chemical, because its resistance is greater than that of the fibers mechanical A suitable source of recycled fiber for these layers Interiors is corrugated cardboard recycled from boxes and cartons.

Scrap paper mixed unclassified - which is the residue after removing the light colored material from higher value - it will generally contain a substantial proportion of Uncoloured chemical fibers of boxes and cartons. Can be used Well as a source of recycled fiber for these inner layers.

A plasterboard lining paper has conventionally a weight that oscillates between 150 and 300 grams per square meter (gmc) and is generally in a more range narrow between 180 and 250 gmc. The role within this range is suitable for use in this invention.

The porosity of the plasterboard lining paper can be determined by the Gurley porosity test established in British standard BS 6538: Part 3: 1987 entitled " Air Permeance of Paper and Board ". This corresponds to ISO 5635/5 - 1986.

This test measures porosity as the time that it takes a known volume of air (100 ml) to pass through a sample of a predetermined area. The result is therefore expressed in seconds.

We have found that the application of a color Continuous printing can result in a large reduction of the porosity. Surprisingly, however, the manufacture of the Gypsum board using printed paper can be made using totally conventional stages. In a production process Typical continuous these stages will be:

unwound from lining paper on a production line with the eventual outer face (in the case of the present invention, the printed surface) on the underside;

supply of wet plaster on the coating paper strip;

conformed of the edges of the band to form edges of the eventual plate of cast;

application of a second band of coating paper to form the face inverse of the plates;

court of resulting continuous material in individual sheets; Y

step of these slices cut through an oven to dry the plaster.

In a cross section through two plasterboard fixed in position with contact edges, each plate has a front face and a back face. In this example, at each edge the plate narrows so that the edge consists in a chamfer as well as a narrow side edge.

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Coating paper on each face front covers each chamfer and side edge, before turning  on the margin of the rear face where it is superimposed by the paper on the back side.

Printing in accordance with this invention is extends over the entire front face and at least part of the chamfer. If convenient, cover the paper around the edge lateral to the end of this paper.

After fixing the plates the way shown, these are attached with tape which adheres to the chamfers  contiguous, without spreading over faces. Then a viscous and mobile joint composition with a paddle to fill the cavity and stay flush with the faces. This binding compound is let harden. This joining technique is conventional, but of according to this invention, the color printed on the paper of coating is selected to match the color of the binding compound.

The invention will now be further described by means of specific examples.

Example 1

Samples of a coating of conventional plasterboard according to this invention before be used to make the plasterboard. The properties of several Coating paper samples, before printing, were measures and was found to be:

one

The paper was printed on the top layer which became the outer surface of the plasterboard, in three Stations of a multicolored flexographic printing machine.

Flexo inks and lacquers used They were all water based. In the first season, the ink It provided a "magnolia" color. It contained 53% pigment, 15% aqueous acrylic resin, 27% water and a small residue formed by minor ingredients. This high pigment content It was intended to provide high color coverage.

The pigment was approximately 99% of titanium dioxide and approximately 1% color pigment. The aqueous acrylic resin contained approximately one third of solids of resin. These were styrene / acrylic copolymers with a weight molecular from 11,000 to 13,000. Thus, the solids content of the Ink was 53% pigment and 6.6% binder resin. This ink is hereinafter referred to as "ink 1".

The next printing station applied a less pigmented ink ("ink 2") containing 20% titanium dioxide pigment dispersed in an aqueous phase that also contained approximately 30% solids of styrene / acrylic binder resin, partially in solution and partially as a liquid phase dispersed
sada

The third printing station applied a lacquer clear ("lacquer 1") without pigment, which consisted almost entirely in a continuous aqueous phase containing approximately 46% of styrene / acrylic binder resin dispersed with a weight molecular of approximately 200,000.

In each of the three print stations, the application was 9.5 ml / m2; the total volume applied was, thus, 28.5 ml / m2. The total solids applied were 15 g / m2.

Porosity and resistance were measured ultraviolet of several samples of coating paper. Be found that the air resistance (Gurley) was of approximately 240 seconds It was found that resistance Ultraviolet paper was very good.

The printing color in several samples is determined on the CIE Lab scale, and compared with the color of the Samples before printing.

It was found that before printing there was a 4.12 difference between the highest and lowest "L" value, but  This was reduced to 1.10 after printing. There was a difference 2.38 between the highest and lowest "b" value before the Print. This was reduced to a difference of 1.32 between the value b higher and lower after printing.

The differences between the highest "a" value and lower were less than 1.0, both before and after the Print. Thus, the effect of printing was to provide Greater color uniformity.

The values L, a, b for the coating Printed were approximately 89, 0.1 and 5.2. In this way, it was from a somewhat lighter color than the unprinted lining with a value L of about 80.

The printed surface of the paper was examined under an scanning electron microscope. At an increase of 250x it was observed that the layer provided a continuous color but It presented a series of cracks. At large increase, the particles individual of the printed pigment could be appreciated and could appreciate a pore structure.

The print coating paper is used to make a plasterboard on a manufacturing line of conventional plates. The speed of the line, the time in the drying oven and the temperatures in that oven were conventional and were in fact the same as they are used for manufacturing using unprinted coating.

Examples 2 a 7

The procedure of Example 1 was repeated. using the same inks and lacquers and additional in several compositions

"Ink 3" was an opaque white ink, similar in composition to ink 1 except for the absence of colored pigment "Lacquer 2" was a matt lacquer that contained 5.8% titanium dioxide pigment and 36% solids of binder styrene / acrylic resin.

The combinations of inks and lacquers are indicated in the following table, along with the Gurley air resistance of papers after printing (example 1 is also included previous). It can be seen that all Gurley values are they are between 200 and 400 seconds, while most are found between 240 and 400 seconds.

2

All these preprinted coatings were successfully converted to plasterboard in a line of normal production without departing from the parameters of normal operation of the production line.

Claims (14)

1. Precoated plasterboard that has a coating paper on its surfaces with a surface material printed on them on all of one side of the plate, characterized by a sufficient print density so that under an optical examination at least one 80% of the surface of the coating paper is covered by the applied printing. 2. Plasterboard according to claim 1, characterized in that the printed material extends over contiguous edges of the plate. 3. Gypsum board according to claim 1 or claim 2, characterized in that the printed material has a weight per unit area in a range between 7 and 30 g / m2 dry weight. 4. Gypsum board according to any of the preceding claims, characterized in that the printing density is sufficient so that under an optical examination at least 90% of the surface of the coating paper on said plate surface of plaster is covered by the applied printing. 5. Plasterboard according to any of the preceding claims, characterized in that the printed material includes printed color. 6. Plasterboard according to claim 4, characterized in that the printing applied is a uniform color in all of one of said face of the plasterboard. 7. Plasterboard according to any of the preceding claims, characterized in that the printed material comprises an overprinted pigmented layer with an additional layer that contains less pigment or does not contain. 8. Plasterboard according to claim 7, characterized in that the additional layer is a colorless or tinted lacquer. 9. Combination of

i)

predecorated plasterboard as per defined in any of the preceding claims and

ii)

a hardenable mobile joint compound for filling joints between plates after fixing,

where the material printed on the plates match the color of the binding compound hard. 10. Method for manufacturing a pre-prepared plasterboard according to any one of claims 1 to 8, characterized in that it comprises the steps of:

print one surface of a band of coating paper,

introduce plaster wet between the opposite surface of said paper web of lining and a second band of lining paper, forming the edge areas of said first band around the plaster to form the edges of the plate, cut into sections and heat to dry the plaster, thus forming a plasterboard with the printing on an exposed face,

characterized in that the printing on the first strip of the coating paper extends in a width such that the entire face of the plasterboard has printing thereon, with a sufficient print density so that under an optical examination by At least 80% of the surface of the coating paper is covered by the applied printing. 11. Method according to claim 10, characterized in that the printing stage is performed by flexographic printing. 12. The method according to claim 10 or claim 11, characterized in that the step of printing a surface of a web of coating paper comprises printing with a pigmented layer and the applied printing provides a uniform color over all of said exposed face of the plate of
cast. 13. Method according to claim 10 or claim 11, or claim 12, characterized in that the step of printing a surface of a strip of coating paper comprises printing the coating paper with a pigmented layer followed by the overprinted with a layer that contains less pigment or does not contain pigment.

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14. A combination of

i)

pre-cooked plasterboard manufactured according to the method of claim 12; Y

ii)

a hardenable mobile joint compound to fill the joints between the plates after fixing,

where the uniform color of printed material on said exposed faces of the plates matches with the color of the binding compound hard.