DE1270388B - Process for the production of hardboard - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

D 21 j

German class: 54 e -1

Number: 1 270 388

File number: P 12 70 388.7-27

Filing date: September 22, 1959

Opening day: June 12, 1968

The invention relates to a method for the production of hardboard, in which a coarse fiber Wood pulp formed into a wet fibrous web, the fibrous web dewatered, a paper web on the dewatered moist fibrous web applied and fibrous web and paper with simultaneous use solidified by heat and pressure to form a hardboard, in which the paper with the Plate surface is connected.

A hardboard with a paper facing can be made according to that in the Canadian patent 537 683 described method. This process results in a hardboard, in which a sheet of paper is so firmly bonded to the surface of the hardboard that it with this consists of one piece. The product of this process is indeed much lighter than his Fiber felt which forms the basis, however, has the disadvantage for some purposes of being yellowish or beige in color to have, especially when a drying oil, such as z. B. linseed oil, has been used to treat the on the lignins, hemicelluloses and other natural binding components of the pulp Support bonding. The linseed oil makes the paper translucent, which means that Bark spots and tufts of fibers tend to show through. The yellow color and the shimmering through result in fiberboard with a simple, unprinted cover sheet an attractive appearance. For darker patterns, such as B. brown walnut or red-brown mahogany, strong positive grain, like oak, don't bother them. However, if there are fine contrasts or light colors, such as light gray, sand colors or mauve, the yellow color and sheen are undesirable.

One way to improve color and sheen is to use a very thick, Apply heavily bleached top layer, for example alpha resin impregnation material. This owns a light color, prevents show through and bonds well with the core. It has, however has shown that such papers are weak on the inside, easy to split and very poor in abrasion resistance own. This can be increased with linseed oil; However, linseed oil causes the undesirable yellow color. In addition, such thick, finished papers are expensive.

Another option is to use paper made with light colored, opaque paper mineral fillers added during the manufacture of the paper. However, it has been found that such papers are a process for the production of hardboard

Applicant:

Abitibi Power & Paper Company Limited,

Iroquois Falls, Ontario (Canada)

Representative:

Dr. W. Müller-Bore and Dipl.-Ing. H. Gralfs,

Patent attorneys,

3300 Braunschweig, Am Bürgerpark 8

Named as inventor:

Rodger M. Dorland,

Maxwell M. Yan,

Stanley H. Baldwin, Ontario (Canada)

Claimed priority:

Canada and the

V. St. v. America September 22, 1958

(759 049),

dated August 13, 1959 (833 384)

badly bond with the core of the hardboard, apparently because the fillers interfere with the natural bond, the hallmark of the invention. The method of the German Auslegeschrift 966 describes the production of hardboard with paper pad. Here, a coarse-fiber wood pulp is applied to a finished paper web with a Applied solids content of about 25 to 40% and this then in a known manner solidified with simultaneous application of pressure and heat. It is preferable to use a stronger connection a thin layer of binder is placed between the two webs of paper and fiber webs, which is conveniently a drying oil. Also the surface covered with such a paper web however, such hardboard is transparent. The paper surface of the plate must therefore always be provided with a nontransparent top layer before further processing.

809 559/34

3 4

The aim of the invention is to create a hard loose, lignin and other natural binding

fiber board, the cover paper surface of which is to reinforce the bond produced by the same components,

moderate, opaque and as desired. Drying oils, such as linseed oil or tung oil, are available as

is colored, preferably white, so that the use of additional binders is particularly suitable. Regarding white

a multitude of grains and colors of possible details of the type of hardboard

is lich. reference is made to Canadian patent 537 683

The method according to the invention is thereby referred to.

indicates that one side is covered with a coating. The paper to which the coating is applied from a pigment and polyvinyl alcohol as a binding agent can vary widely. It can contain wood pulp, sulphite, Medium-sized paper web with its non-coated, neutral sulphite, semi-chemical strength and soda dates Side on the dewatered moist fibrous web containing cellulose alone or in mixtures. Brought up will. preferably papers with a high degree of wood pulp

The coating only on the outer side has content and a weight per square meter of 24 to the advantage that it gives a good opacity and uses 124 g, for example newspaper and address at the same time the good natural binding properties - book, catalog, rotogravure and tissue papers. in the In the case of newsprint, it has been shown that an uncoated, unfilled surface with open fibers and a strong adsorptive capacity - the coating is best on the wire side of the paper the inner surface is preserved to web, while the top or felt one Firm bond between the paper and the fiber side as the inside with the felt sheet of the plate-to-plate base to be able to achieve. ao is brought together. This generally gives

The application of the coating on the outside - both a better coating and a better one side of the cover paper is, however, only with the duly used polyvinyl alcohol possible. The paper to be applied to the plate is on Since the one side consisting of pigment and binder is treated with masses, in general The coating is on the outside of the cover paper and is similar to that used for paper coating when the plate is hot-pressed, the surface of the are. These mainly consist of an un-polishing sheet with the fresh coating in calming-translucent pigment that usually tion. If you now use binders other than white, and a binder that contains the pigment polyvinyl alcohol, this is how the coating under the particle bonds with each other and with the paper. Influence of strong heat, high pressure and small amounts of other substances, for example Dides water present during the hot pressing agent and substances to prevent the sens sticky, and the coating sticks to the polishing foaming, may be present, hang sheet metal. This worsens the surface. The untreated surface of the paper becomes on surface not only of the hardboard, which is just turned into a fiber web with a solids content of 25 to the press was, but also all the following, 35 40% applied before this fiber web into the if the polishing sheet is not cleaned. The at press is introduced in the same way as it is the Adhesion of the coating occurs irregularly, according to Canadian patent 537 683 for uncoated Part of the remnants of the coating from the polishing paper are described. When using light Transfer the sheet to the next hardboard. Tissue paper is a lower solids content too-on the edges even the paper remains on the polishing 40 nonchalant. When heat and pressure are swirled in the press hang and will be torn off so that the plate ken, call the natural binding components of the must be discarded. After forty or more pulps along with additional binders that fifty Pressing processes must therefore, if necessary, the production on the untreated surface of the interrupted to clean the polishing plates were applied to clean paper, an intimate, firm Binbern - a very costly measure. If the paper and the fiber felt are thickened, The use of polyvinyl alcohol as a binder can be used to achieve maximum opacity However, four hundred preferred pigment is titanium dioxide of the rutile crystalline process be performed. type that has a high refractive index of 2.76 be-The coating of paper with a coating sits. However, other pigments can also be used Pigment and binder are known per se, such as titanium dioxide but not their use in the anatase form of the invention, zinc oxide and zinc sulfide. Pigments that Appropriate way for the production of laminated not as high a refractive index as the aforementioned hardboard. th can also be used niken made the defibering and finishing 55 less satisfactory. Examples of such other pigvons Fiber material, such as wood chips, and the ments are barium sulfate, calcium sulfate, lithopone, subsequent shaping and dehydration of the wet calcium carbonate, talc, clay and diatomaceous earth. Web on a Fourdrinier machine and the mixture of pigments can be used consolidation with simultaneous application of heat in order to reduce costs, to affect the gloss and pressure to make a hard, compact fiber flow to improve printability, the so-called mass to produce caused by the hemicelluloses, called "metalmarking", etc., like it Lignins and other natural binding components that require special circumstances. Colored Pigdes Wood is cemented. If desired, ments can be used if a durable special additives are added, for example colored top layer or the desired one Wax or other sizing agents as well as an additional base for a printed top layer are created binding substances, e.g. B. Synthetic resins such as phenol should be.

formaldehyde resin. It is preferred that the pigment particles have an additional

Binder used to have the small particle size due to the hemicellu-

Claims (1)

5 6 Zugmixture are dispersed. Sodium silicate, Na- The invention is in the following embodiment- trium hexametaphosphate, sodium pyrophosphate, Na- example explained: trium tetraphosphate, ammonium and sodium casein example nate and various cationic wetting agents and “,. ..., " many other similar substances can be used as a disper- 5 ^Es ^ ^{Γαε eme} coating compound made from: Lubricants can be used. Titanium dioxide (rutile crystal type) .. 200 parts by weight The polyvinyl alcohol is preferably used as sodium hexametaphosphate wise in an amount of 5 to 10% of the pigment _{(as dispersant) Vl part by} weight weight. One can, however, as shown below will also use much higher amounts. io polyvinyl alcohol (5% solution) 240 parts by weight The ratio of solid to liquid substances in water is 325 parts by weight Coating mixture can be used to adapt to the desired weight of the coating and the weight required for the coating. The pigment has been thoroughly moistened and The device used to apply the coating varies dispersed by homoing the sludge. Preferably, the coating mix 15 cleverly contains a generator or a high capacity mixer 25 to 30, for example 28% solids. became. A small amount of an anti-foam agent The preferred diluent for the over- (consisting of a mixture of sulfonated! Zug is water, however other suitable castor and pine oil) has been used to make the Carriers are used. Control foam and ensure even build-up To achieve the weight of the load applied to the paper. Coating can be between 1 and 34 g / m ² (dry). This coating was made on a slot nozzle and is preferably in the range of the load-bearing machine in an amount of 11 g of solids 5 to 24 g / m ² . If the weight of the coating is increased per square meter on the screen side of a newspaper, the opacity and thus also the printing paper with a square meter weight of opacity increases. 25 65 g and a content of 80% wood pulp and Applying the coating to a surface applied 20% sulfite pulp. After numerous treatments, the sheet of wood pulp paper can then be dried to harden the coating. A drive can be carried out, for example on a wet hardboard fiber web, from a single-slot nozzle, roller, knife, rotogravure or a mixture of hard and soft wood in brush application machines. The water can be prepared from the manner described in Canadian Patent 537,683 coated web on a conventional dryer,
evaporated, for example an air duct tung oil was applied in an amount of 15 g / m ² to the dryer, a conventional paper dryer or uncoated side of the newsprint using radiant heat or hot. The newsprint was then absorbed into a partially dehydrated hardboard sheet on combustion gases of liquid or gaseous fuel. If the cover sheet is to be printed, bring it, namely the side with the coating compound, the dried, coated web wound up on the outside, so the side treated with tung oil can be wound on the inside so that it can be put on a suitable press. For example, a printing press with an endless web to The felt base with the coated paper guide, can be printed. Instead of this, the 4 ° top layer was then cut into individual sheets for 13 minutes at a pressure of up to 45.5 kg / cm ² and a temperature of 166 ° C and then pressed on a press with single sheet feed. The resulting 6 mm thick plate was to be printed. The coated surface of the sheet, which is then heated at approximately 143 ° C. for 372 hours, can be printed on without overcalendering; delt and brought to 5% moisture,
However, it can also be over-calibrated or smoothed before printing, which has proven to be advantageous from the type of cover layers, the desired pattern and the correct re-use of polyvinyl alcohol in an amount of 10 to 40 would depend on required smoothness. Various, and preferably about 25 percent by weight of the pig adhesive, e.g. B. thermosetting resins, thermo- mentes, such as titanium dioxide, are provided. Such plastic resins, including vinyl compounds, have sufficient toughness without the use of a dry polyvinyl alcohol, latices and polymerizable oils as adhesives, drying oils can be applied to the uncoated strength and strength and is characterized by high surface area of the paper, to the degree of whiteness. It is recommended that such a cover achieve an additional bond. Examples of layers in an amount of 15 to 30, preferably suitable drying oils are linseed oil, soybean 55 22 g / m ² , solids to be applied,
bean oil, tall oil and tung oil. These drying hardboard with a top layer according to the oils can be mixed with other binders. Urea-formaldehyde resins, Vi-60 covered. The top layer, however, is intimate with the nylharzen, Aikydharzen and butadiene-styrene latices. Hardboard base connected.
About 5 to 24 g / m ^{2 of} drying oil are preferred Various decorative and / or protective ^ Substances, e.g. B. Drying Oils, Alkyd Resins, and Waxes 65 1. Process for making hard fiber can on the upper or coated surface, with which a coarse-grained wood pulp becomes of the cover sheet before solidification in the hot, a wet fibrous web, the fiber press be applied. Dewatered fabric web, a paper web on the watered moist fibrous web applied and fibrous web and paper under simultaneous Application of heat and pressure to solidify a hardboard in which the paper is connected to the plate surface, characterized in that one side paper web provided with a coating of a pigment and polyvinyl alcohol as a binder with its uncoated side applied to the dewatered moist fibrous web will. 2. The method according to claim 1, characterized in that the weight of the coating applied to the paper is about 5 to 24 g / m ³ . 3. The method according to claims 1 and 2, characterized in that a strong wood pulp-containing Paper weighing approximately 24 to 120 grams per square meter is used. 4. Process according to Claims 1 to 3, characterized in that titanium dioxide is used as the pigment and polyvinyl alcohol can be used in an amount of 5 to 10% by weight of the pigment. Considered publications:
German Patent No. 839 756;
German Auslegeschrift No. 1034 966;
British Patent No. 700743;
U.S. Patent No. 2,832,267. 809 559/34 5.68 © Bundesdruckerei Berlin