WO2007133925A1 - Surface application of decorative materials to paper for use in laminates - Google Patents

Abstract

A laminate structure and method of production is described whereby a decorative layer includes visual characteristics that are formed by surface application of materials to the decorative layer.

Description

SURFACE APPLICATION OF DECORATIVE MATERIALS TO PAPER FOR USE IN

LAMINATES

Inventors: Stephen T. Foley, Reed H. Walsh

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119(e) of

U.S. provisional application serial number 60/746,707, filed on May 8, 2006, which

is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] Decorative laminate materials are used in such applications as

countertops, floors, paneling, furniture surfaces, and the like. A common method

of manufacturing such laminate materials uses one or more substrate layers of

material such as saturating Kraft paper (for example, as manufactured by

MeadWeslvaco Corporation). Several "base" layers may provide thickness,

stability, and strength to the laminate.

[0003] A second tvpe of laver is typically added on top of the substrate layers,

as a decorative or "decor" layer, for example containing a printed pattern such as

a wood grain, or a color.

[0004] A third "overlay" layer ma}' be added to provide durability such as

abrasion resistance or waterproofing, or give other desired characteristics. The

third layer may be transparent so that the decor layer is visible yet protected from wear.

[0005] All three types of layers may typically be produced by methods known

In the art. While the different layers may have special properties, they typically

share a characteristic ability to become saturated with resin materials, then

heated and pressed to result in a product including a sandwich of layers

collectively known as decorative laminate. The transparent layer may be based

upon a special "overlay" paper or paperboard made up of materials such as

wood fiber selected to become essentially invisible after the saturating and

pressing operation. A transparent overlay paper is useful for permitting the

decor layer to be readily visible.

SUMMARY

[0006] A laminate structure, and a method of producing the same, is

described whereby at least a part of the materials contributing to the appearance

of a decorative paper are applied to the surface of the paper, a process that

provides flexibility in adjusting the visual appearance of the decorative paper

and the laminate product.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 illustrates a typical laminate structure;

[0008] FFG. 2 illustrates a variation of the laminate appearance by materials added to the overlay layer;

[0009] FIG, 3 illustrates preferred embodiments of the invention directed to

surface application of materials to the decorative layer; and

[0010] FϊG. 4 illustrates a method for forming a decorative layer containing

surface-applied materials.

DETAILED DESCRIPTION

[001 IJ FIG. 1 illustrates a typical laminate structure 100, shown as an

exploded view of the several layers. One or more base layers 110 are typically

provided, which may be made of a substrate such as saturating Kraft paper. Base

layers may provide thickness, stability, and strength to the laminate structure.

[0012] A decorative or "decor" layer 120 is typically added on top of the

substrate layers 110, for example containing on either or both sides a printed

pattern such as a stone appearance (e.g., granite or marble), a wood grain, or a

color. More than one decorative layer 120 may be used, although typically one is

sufficient, particularly if the decorative layer 120 is opaque.

[0013] An overlay layer 130 is typically added on top of the decorative layer

120, to provide durability such as abrasion resistance or waterproofing, or give

other desired characteristics. As is known in the art, the third layer is typically

designed to become transparent so that the decor layer is visible yet protected

1 from wear,

[0014] Although the laminate structure 100 is shown having a decorative

pattern on only one side (e.g., the "top" side), it should be understood that either

or both sides could be produced with a decorative pattern if desired. Although

the layers 110, 120, and 130 (and other layers as described in the additional FIGs.)

are shown having no thickness, it is understood that the layers have a finite

thickness (for example, a starting thickness determined by the thickness of the

material used for the layer, such as saturating Kraft paper) to provide strength

and other desired properties. The final thickness may differ from the starting

thickness due to compression during the lamination process. The thicknesses of

each layer may be different.

[0015] FIG. 2 shows a decorative laminate 200 where decorative or inclusion

materials 231 have been added to overlay layer 230 during production on a paper

machine. (Similarly inclusion materials (not shown) could have been added to

decorative layer 220 during its production on a paper machine.) With such a

method, the high speed of a paper machine, and the large amounts of furnish

(paper pulp, additives, etc., possibly including inclusion materials) and the time

needed to reach a steady state production of a uniform product may result in

significant waste when it is desired to produce only limited amounts of a

particular decorative paper. Often thousands of pounds of product must be produced, when much less is actually required, and some of this product may be

o f f-specif ication .

[001b] In accordance with preferred embodiments of the invention, an

exemplary laminate structure 302 is shown in FIG. 3. In the example shown, one

or more base layers 110 are provided. A decorative layer 322 is provided having

a particular appearance. At least a portion of the appearance, for example

features 323, is provided by a surface operation such as spraying, curtain coating,

roll coating, blade coating, conventional saturating processes, dry sprinkling of

materials, or like operations either on the paper machine or in an off-machine

process that may be rapidly changed, resulting in much less product waste than

of such features were applied into the paper furnish itself. Even within the same

production run on a paper machine, or in an oft-machine process, a second

decorative paper 324 may be produced, with at least a portion of the appearance,

for example features 325, provided by a surface operation such as spraying,

curtain coating, roll coating, blade coating, conventional saturating processes, dry

sprinkling of materials, etc., either on the paper machine or in an off-machine

process. This decorative paper 324 may be used for producing a second laminate

structure 304. In FIG. 3, the flexibility of such a method is illustrated by the

example of decorative paper 324 differing in visual appearance from decorative

paper 322, in several aspects including color, shape, size, and size distribution of the visual features. Saturation components,, such as melamine formaldehyde

resin, may be included in the coating, such that part or all of the saturation

process is combined with the coating process. Materials to provide wear

resistance may also be included in the coating. Thus the coating may provide one

or more of visual characteristics, abrasion resistance, and saturating properties.

[0017] The decorative paper thus produced may also be used in non-laminate

products and applications.

[0018] An overlay layer 330 may a!so be provided. Although only one overlay

layer 330 is shown for the examples in FIG. 3, more than one overlay layer can be

incorporated in the laminate 302 or 304, for example to provide greater perceived

depth, better durability, etc. Possible applications for the laminate (or for the

layers or papers in a non-laminate usage) include floors, wall paneling, ceilings,

countertops, and fixtures. In some applications an overlay layer may not be

needed. For example if the end product is wall paneling, ceilings, wallpaper, or

lampshade material, a wear resistant overlay layer may not be needed. On the

other hand, floors and some countertops may use a wear resistant overlay layer.

[0019] Other possible applications include the use of decorative papers for

translucent panels and shapes, decorative sheet molding, lamp shades, home

storage containers, other decorative products, and for scrapbooking applications.

Some of these applications are laminated products, and some use the decorative paper or sheets without lamination.

[0020] As an exemplary embodiment a melamine laminate may be created

comprising several phenolic saturated Kraft bottom layers 110, followed by a

melamine saturated decorative layer 322 or 324 with a particular pattern, then by

an overlay layer 330 being the top most layer.

[0021] The thickness of the final laminate product may range from 0.030

inches to 3/4", The thickness of an exemplary overlay layer may be approximately

0.005 inches.

[0022] In one embodiment, decorative features added by a surface application

may include fiber, filler, pigment, pearlescent particles, glitter, and other

decorative materials that may be fed to a surface application device such as a

curtain or spray coater, dry sprinkling, etc., along with chemicals such as

polymers to make the application be evenly distributed or splotchy. Other

decorative features may include natural fibers such as banana fiber, moss, sisal,

and others, metal chop and other unique materials such as holographies.

Splotchiness (that is, size and distribution of the decorative effects) may also be

adjusted by means of parameters such as Mow rate of the coating, and solids level

in the coating. The visual effects can range in size from "larger scale" (more than

0.25 inch in at least one dimension), down to smaller scale (such as 20-6000

microns). Useful solid particles that may be applied include mica, glitter particles such as metallized PET (polyethylene terephthalate) or metal foil cut into

different sizes and shapes. The material vendor may provide the material in

"shredded" form. Some of this product may be "off the shelf" and some may be

custom-made as needed. Thus the customized visual features resulting from the

use of surface-applied materials into decorative layers 322 or 324 may include

one or more of color, size, shape, reflectiveness, and other visually perceived

characteristics, or the materials may provide wear resistance. It should be noted

that the inventive method allows visual effects to be used which include particles

or features that are larger than what can be applied by conventional printing

means, for example, solids flecks or particles greater than Vi" in at least one

dimension. The inventive method may allow the user to dispense with a printing

step that would otherwise be needed to provide a desired character or

appearance, or a printing step could be applied to the paper before or after

treating the paper with the inventive method.

[0023] Other useful inclusion materials include materials with iridescent or

opalescent appearance. In some cases the inclusion materials may be chosen to

provide a realistic appearance such as a stone appearance, but in other cases they

may be ut>ed to provide an eye-catching appearance that may not represent a

particular natural material.

[0024] Other useful decorative materials may include coloration materials that may be applied uniformly or non-uniformly, on the paper machine or off-

machine. A coating may be used such as a mixture of melamine or other resin,

adhesives such as PVOH, starch, binder, polymers such as acrylic or polyester,, or

other coatings or combinations thereof that can be laid down on the paper. The

binder may not all be the normal resins used in laminates. Particles or inclusions

may then be sprinkled onto the coated paper, or particles and inclusions can be

pre-irtixed into the coating then applied through various methods. Some useful

functional materials include wear resistant or abrasion resistant materials such as

grit added or p remixed into the coating, or dry-sprinkled onto the coating after

the coating is applied. The wear or abrasion resistance thus provided in a

decorative layer may eliminate the need for an overlay layer. In some cases a top

coating may be applied over the first coating.

[0025] FlG. 4 illustrates an exemplary method for making the decorative layer

322 or 324 using a paper machine, A forming wire 410 in the form of an endless

belt passes over a breast roll 415 that rotates proximate to a headbox 420. The

headbox provides a fiber slurry in water with a fairly low consistency (for

example, about 0.5% solids) that passes onto the moving forming wire 410.

During ά first distance 430 water drains from the slurry and through the forming

wire 410, forming a web of wet fibers. The slurry during distance 430 may yet

have a wet appearance as there is free water on its surface. At some point as drainage continues the free water may disappear from the surface, and over

distance 431, water may continue to drain although the surface appears free from

water. Eventually the web is carried by a transfer felt or press felt through one or

more pressing devices such as press rolls 421 that help to further dewatering the

web, usually with the application of pressure, vacuum, and sometimes heat.

After pressing, the web is dried, These steps as described so far are well known

in the art of papermaking.

[0026] The paper web created by this process may comprise fibers that are

chosen and prepared such that they eventually become invisible when

incorporated with resin into the laminate structures previously described, Other

components may be added which remain visible in the laminate structures,

[0027] As an example, decorative or inclusion material, liquid or solid, may be

added to the slurry shortly after leaving the headhox. Addition at these locations

provides good mixing throughout the slurry. Standard papermaking practice is

to try to achieve uniform distribution of solids in the slurry, leading to good

"formation" of the paper product. However, if the inclusions have different

physical or chemical properties from the usual paper fibers, it is possible that

additives may be used that would cause the inclusions to form small localized

groupings, for example to form a variegated distribution in the inclusion layer

being produced by the process. The point at which inclusion materials are added may influence their orientation in the web.

[0028] Decorative or inclusion materials may be added when the web being

formed has just left the headbox, and is fairly fluid, for example in the first

distance 430. Material added at this point, whether liquid or solid, may be less

likely to distribute evenly because the slurry of fibers is becoming set. Therefore

migration of the decorative materials or inclusions across the web or into the web

may be somewhat limited. This could for example cooperate with a means such a

sprayer which may apply decorative material or inclusions less uniformly than

possible when such additions are made at the headbox. Less uniform

distribution may provide more realism for some types of simulated natural

materials.

[0029] Decorative or inclusion materials may be added when the web being

formed is further away from the headbox, and less fluid, for example in the

second distance 431. Materials added at this point may be expected to remain

closer to the surface of the web. Adding materials here might reduce the

appearance of depth in a final laminated product. However, it could facilitate

forming "clumped" or variegated decorative materials or inclusions for example

by spraying onto the web a suspension of such materials in a coarse spray-

pattern.

[0030] Decorative or inclusion materials, besides being added to the web at the "wet end" of the paper machine, for example in locations 430, 431, may also

be added at other locations toward the dry end of the paper machine. For

example a decorative paper 320 or 324 being formed on the paper machine may

be treated by application of materials using a curtain coater 44O₇ or a spray coaler

450, or dry sprinkler or other means (not shown). As noted above, these devices

may be located at other positions, including wet end locations 430, 431. Typically

one or more drying sections such as 461, 462, and 463 may be used to dry the

papei .

[0031] Besides applying decorative or otherwise functional materials on the

paper machine as shown in FIG. 4, such materials may be applied in off-paper-

machine processes as well, using similar coating or application methods.

Materials may be applied by dry-sprinkling.

[0032] Besides the materials added to the web for enhancing visual

appearance, other materials may also be added for providing durability and wear

resistance. In some cases materials that enhance visual appearance may also

provide durability and wear resistance.

[0033] Methods of making and using the laminate structure in accordance

with the invention should be readily apparent from the mere description of the

laminate structure and its varied appearances as provided herein. No further

discussion or illustration of such methods, therefore, is deemed necessary. [0034] While preferred embodiments of the invention have been described

and illustrated,, it should be apparent that many modifications to the

embodiments and implementations of the invention can be made without

departing from the spirit or scope of the invention. Although the preferred

embodiments illustrated herein have been described in connection with a

laminate structure and with a stone or wood appearance, these embodiments

may easily be implemented in accordance with the invention in other structures

or to simulate other appearances. The decorative sheets described herein may be

used for both laminate and non-laminate applications.

[0035] It is to be understood therefore that the invention is not limited to the

particular embodiments disclosed (or apparent from the disclosure) herein, but

only limited by the claims appended hereto.

Claims

CLAIMS[0036] What is claimed as new and desired to be protected by Letters Patent ofthe United States is:

1. A laminate structure comprising

At least one base layer, and

a decorative layer comprising a pattern; said pattern comprising at

least in part a visually perceived or wear-resistant characteristic achieved by a

surface application to said decorative layer.

2. The laminate structure of claim I₇ further comprising at least one

overlay layer.

3. The laminate structure of claim 1 or 2, wherein at least one of said

layers comprises saturating paper.

4. The laminate structure of claim 1, wherein said surface application is

by a curtain coater, spray coater, roll coater, blade coater, saturating process, or dry

sprinkling.

5. The laminate structure of claim 1, wherein said surface application is

carried out in an on-paper machine operation.

6. The laminate structure of claim 1, wherein said surface application is

carried out in an off-paper machine operation.

7. The laminate structure of claim ϊ, wherein said visually perceived or

wear-resistant characteristic is chosen from the group consisting of shape, color,

reflectivity, refractive index, opacity, size, size distribution, and wear resistance.

8. A decorative sheet comprising

A fibrous layer; and

a visually perceived or wear-resistant characteristic added to said

fibrous layer by a surface application to said fibrous layer.

9. The decorative sheet of claim 8, further comprising at least one overlay

layer.

10. The decorative sheet of claim 8, wherein said fibrous layer comprises

saturating paper,

11. The decorative sheet of claim 8, wherein said surface application is by a

curtain coater, spray coater, roll coater, blade coater, saturating process, or dry

sprinkling.

12. The decorative sheet of claim 8, wherein said siirface application is

carried out in an on-paper machine operation.

13. The decorative sheet of claim 8, wherein said surface application is

carried out in an off-paper machine operation.

14. The decorative sheet of claim 8, wherein said visually perceived or

wear-resistant characteristic is chosen from the group consisting of shape, color,

reflectivity, refractive index, opacity, size, size distribution, and wear resistance.

15. A method of creating a laminate structure, the method comprising;

providing one or more base layers;

providing a decorative layer comprising a pattern; said pattern

comprising at least in part a visually perceived or wear-resistant characteristic

achieved by a surface application to said decorative layer.

16. The method of claim 15, wherein said stirface application is by a curtain

coater, spray coater, roll coater, blade coater, saturating process, or dry sprinkling.

17. The method of claim 15, wherein said surface application is carried out

in an on-paper machine operation.

18. The method of claim 15, wherein said stirface application is carried out

in an off-paper machine operation.

19. The method of claim 15, wherein said visually perceived or wear-

resistant characteristic is chosen from the group consisting of shape, color,

reflectivity, refractive index, opacity, size, size distribution, and wear resistance.

20. The method of claim 15, further comprising the step of providing an

overlay layer.

21. The method of any one of claims 15 ~ 20, further comprising saturating

said layers with a saturating resin.

22. The method of claim 21, further comprising applying heat.

23. The method of claim 21, further comprising applying pressure.

1?

24. A method of creating a decorative sheet, the method comprising:

providing a fibrous layer;

applying to said fibrous layer a visually perceived or wear-resistant

characteristic achieved by a surface application to said fibrous layer,

25. The method of claim 24, wherein said surface application is by a curtain

coaler, spray coater, roll coater, blade coater, saturating process, or dry sprinkling.

26. The method of claim 24, wherein said surface application is carried out

in an on-paper machine operation.

27. The method of claim 24, wherein said surface application is carried out

in an off -paper machine operation.

28. The method of claim 24, wherein said visually perceived or wear-

resistant characteristic is chosen from the group consisting of shape, color,

reflectivity, refractive index, opacity, size, size distribution, and wear resistance.