CS71292A3 - Hydrophobized fibreboard and process for producing thereof - Google Patents

Abstract

To produce waterproofed insulating wood fibre board by the wet process, the wood fibres are mixed with a bitumen-free waterproofing agent in a quantity of at most 5 % by weight, preferably 2 % by weight, relative to the wood fibres, in the form of an aqueous dispersion of reinforced natural resins of 45 % solids content. In order to fix the waterproofing agent on the individual wood fibres, a fixing agent in the form of an aqueous solution is then admixed and mixed with the wood fibres and the waterproofing agent. If appropriate after temporary storage, a fibre mat is formed from the waterproofed wood fibres and this is further processed in the manner conventional per se to give the insulating wood fibre board. <IMAGE>

Description

JUDr. MIloS VŠETEČKAadvokát

further relates to a process for the production of a hydrophobized fiberboard, as defined above, by a wet process.

Background Art

Known wood-fiber boards are hydrophobized with resin emulsion additives, see DIN 68752 or ΟΝΌΕΜ 3006, and are referred to as vitreous plates. In this case, the fiberboard contains an additive of 12% by weight of resin, based on the weight of the wood fibers (atro). In the known plates, not only the addition of the resin, the harmful environmental protection, but also the dark brown black color of the plate and finally the limited resistance to dampness are disadvantageous. DE-A-2Q 34 208 discloses a hydrophobic base protective agent for particle boards, not for wood fiber boards. This hydrophobic and basic protective agent consists primarily of longer carbon chain paraffin hydrocarbons with n- and isoalkanes of at least 30% by weight and optionally with artificial hydrocarbon resins.

U.S. Pat. No. 4,256,491 discloses a composition for hydrophobising articles wherein it is surface-coated or processed into sheet films. It is not possible to deduce from the aforementioned document the processing of the fiber composition into a known "

EP-A-107 155 relates to a method for improving water resistance in molded parts which are produced by extruding a foamed fiber material containing pulp using an isocyanate-containing resin and an unstressed isocyanate-containing resin portion and molded parts to be time separated from each other.

It is an object of the present invention to provide a hydrophobized wood chip board which does not have the above-mentioned disadvantages and is free of resin.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The object of the present invention is to provide a hydrophobised fiberboard which comprises a resin-free hydrophobizing agent, wherein the hydrophobizing agent is present in the sheet at a maximum of 5% by weight, preferably 2% by weight, based on on wood fibers, and that the hydrophobising agent is fixed to the individual wood fiber fixing means.

According to a preferred embodiment of the present invention, the fixing means is an organometallic compound.

According to another preferred embodiment of the present invention, the fixing agent is an oligomeric condensate of aluminum dicyandiamide.

According to another preferred embodiment of the present invention, the fixing agent is a dispersion of crosslinked natural resins.

According to another preferred embodiment of the present invention, the wood fiber fixing agent is applied in the form of an aqueous solution. The wood fiber board of the invention exceeds the known, additive resin emulsions of hydrophobized fiberboard in several properties. For example, the fiberboard according to the invention has a higher bending fracture strength, and this higher bending fracture strength remains in water even after 24 hours of laying the fiberboard according to the invention. In addition, the water intake of the wood fiber board according to the invention is considerably reduced compared to the known wood fiber boards which are hydrophobic by the addition of a resin emulsion.

Another advantage of the fiberboard according to the invention is that it no longer has a dark brown or black color as the resin plate, but resembles normal wood fiber boards which are not hydrophobic by the addition of resin.

The invention further provides a process for the production of a hydrophobized wood-fiber board as defined above by wet process comprising a resin-free hydrophobizing composition comprising a resin-free hydrophobizing agent in an amount of at most 5%. weight, preferably 2% by weight, based on the wooden liner, and then adding the fixative and blending with the wood fibers and the hydrophobizing agent to fix the hydrophobizing agent on the individual fibers, and optionally, after the temporary storage, to form a fiber mat from the hydrophobized wood fibers. which is further processed by the superfibrous plate. The following table compares the essential properties of the inventive plate labeled as BVft-plate with the corresponding -3-properties of hydrofobised resin additive plate (s) *

Table

Property Resin Plate 15% BVR Plate Water intake after 24 h - water storage 53,16% 26,13% Dry bending strength 10,43 kp * cm 2 2 11,40 kp * cm Bending strength at wet 2.25 kp * cm 2 8.44 kp * cm 6

In a single figure, there is shown a schematic of a production line for producing hydrophobized fiber boards according to the invention. EXAMPLES OF THE INVENTION

The method of producing a wood fiber board according to the invention does not differ from fiber production to mixing from the method of making known wood-fiber boards (resin boards) of hydrophobic additive emulsion emulsion.

In the mixing calender, a hydrophobic agent, for example, a crosslinked natural resin in the form of an aqueous dispersion with 45% by weight solids (trade name Furtin BVR 50, manufacturer: Franz v. Furtenbach, GmbH, Neustadt), is first processed. After a stirring time of 10 minutes, a fixative is added, for example an oligomeric condensate of aluminum dicyandiamide in the form of an aqueous solution (trade name FURTOFIX B3, the same manufacturer), to fix the hydrophobizing agent on wood fibers *

In total, up to 1.5%, preferably 0.5 to 0.8%, by weight of the hydrophobising agent and up to 1%, preferably 0.8%, of fixative * have been added based on the proportion of wood fibers.

After the appropriate stirring time, for example 15 min, the pulp slurry is pumped out and stored in a storage vat until processed. Another way of working, such as pressing and drying the manufactured fiber boards, is again the method of working in the production of resin boards.

A significant advantage with the use of resin-free hydrophobizing agents, such as the hydrophobising agent exemplified, as opposed to the use of resin emulsions, is the pH at which the work is carried out. When the resin emulsion is added, the pH of the pile is adjusted to 4.5 to 4.7 by addition of aluminum sulphate, i.e. to the acid range. By using the hydrophobising agent according to the invention, the improved physical properties achieved according to the invention reach a pH range of from 5.5 to 7.0, i.e. approximately in the neutral range. As a result, it is possible to reuse the return water from the sieve machine and the press without dilution as dilution or production water, as indicated in the flow diagram in the drawing.

Several examples will now be given for fiberboard according to the invention made of water-resistant resin-free waterproofing agents. Individual physical values obtained are also mentioned. Example 1

Solid fiber grinding degree 68 "+ 9 '% BVR-50 (45-percent) + 1.9% aluminum sulfate

Density: 260 kg.m “^ Thickness:

Flexural strength: 17.7 kp.cm Water intake: 19.9% Example 2

Solid fiber grinding degree 68 "+ 9% BVR-50 + 0.8% aluminum sulfate +0.5% Furtofix P3 (50-percent) pH 6.0

Density: 242 kg.m “^ Thickness:

Flexural Strength: 13.2 kp.cm Water Intake: 26.5% Example 3

Solid fiber grinding degree 68 "+ 6% BVR-50 + 1.9 $ aluminum sulfate * 1% Furtofix P3 = binderPH 5.3

Density: 259 kg.m ~ ^ Thickness —2

Flexural strength: 18.6 kp.cm Water intake: 25.1% 180 g atro (450 g) 36 g3.4 g 13.5 mm pH 5.3 180 g atro36 g1.5 g1.8 δ 11.5 mm 180 g atro24 g3,4 g3,6 g 13,6 mm -5- Example 4

Solid fiber fiber grinding 68 "+ 3.3% BVR-50 4 0.8% Furtofix P3 + 0.5% aluminum sulfate pH 6.0

Density: 258 kg »m" 3 Thickness: 17.0 mm

Flexural strength: 10.9 kp.cm Water intake: 10.8% Example 5

Solid pulp grade grind 68 "+ 3.3% BVR-50 4 0.8% Furtofix P3 pH 6.0

Density: 236 kg.m “3 Thickness: 16.0 mm -2

Flexural strength: 13.5 kg®cm Water intake: 18% Example 6

Solid fiber grinding grade 68 "4 1.6% BVR-50 4 0.5% Furtofix P3 4 0.35% aluminum sulfate pH 6j5

Density 226 kg.m-3 Thickness: 16.1 mm _2

Flexural strength: 14.2 kp.cm Water intake: 18.6% Example 7

Solid fiber grinding degree 38 "260 4 1.6% BVR-504 0.5% Furtofix P3pH 6.5

Density: 266 kg.m ”3 Thickness: 20.3 mm -2

Flexural strength: 16.0 kg.cm Water intake: 14.1% Example 8

Solid fiber grinding grade 38 "4 1.6% BVR-50 4 0.5% Furtofix P3 + 0.35% aluminum sulfate 220 g atro 16 g3.6 g1.5 g 220 g atro 16 g3.6 g 220 g atro8 g 2.7 g 0.75 gg atro (620 g), 25 g, 6 g 260 g atro9.25 g 2.6 g 0.91 g -6- pH 6.3

Density: 249 kg.mBending Strength: 12.1 kp.cmWater Intake: 11.7% Example 9

Solid fiber grinding degree 38 "+1.2% BVR-50 + 0.6% Furtofix P3pH 60

Density: 236 kg.mBending strength: 10.6 kp.cmWater intake: 11.6% Example 10

Solid fiber grinding grade 29 "1.6% BVR-50 + 0.5% Furtofix P3pH return value: 5.6PH 5.3

Density: 245 kg.mBending Strength: 10.6 kp.cmWater Intake: 46.5% Example 11

Solid fiber grinding degree 29 "+ 1.6% BVR-50 + 0.5% Furtofix P3pH return water value: 5.6PH 5> 4

Density: 224 kg.m ”^

Flexural strength: 14.1 kp.cm 'Water intake: 21.9% -3 -3 -3 -2.-2 -2 -2

Thickness: 20.9 mm

Thickness: 23.5 mm 260 g atro6.93 g 3.12 g 260 g atro (620 g) 8.26 g2.6 g

Thickness: 26.8 mm 173 g atro (413 g) 5.5 g 1.73 g

Thickness: 17.3 mm Example 12

Solid substance fiber grinding degree 32 "+ 1.6% BVR-50 + 0.5% Furtofix P3pH value for return water: 5.1pH 4.7

Density: 250 kg.m '

Flexural strength: 12 kp.cmWater intake: 268.1% 190 g Atro (452 g) 6.76 g1.9 g

Thickness: 20.5 mm -3 -2 -Ί- Example 13

Solid fiber grinding degree + 2.0% BVR-50 + 0.5% Furtofix P3 at return water value: 5.1 pH 4.7 -3

Density: 280 kg.m

Flexural strength: 6.7 kp.cm "Water intake: 239.9% Example 14

Solid fiber grinding degree + 1.6% BVR-50 + 0.5% Furtofix P3pK value for return water: 6.5pH 6.5

Density 237 kg.m “· 5

Flexural Strength: 8.5 kp.cmWater Intake: 19.8% Example 15

Solid Fiber Grinding + 2.0% BVR-50 + 0.5% Furtofix P3pH Backwater Value: 5.7pH 5.1

Density: 250 kg.m -2

Flexural strength: 18.5 kpoemWater intake: 27.7% Example 16

Solid fiber grinding degree + 2.0% BVR-50 + 0.5% Furtofix P3pH return value: 5.2pH 4.9

Density: 247 kg.m “^ ~

Flexural strength: 19.5 kp.cm “Water intake: 184.5% Example 17

Solid pulp grinding degree + 2.0% BVR-50 32 "190 g atro 8.45 g1.9 g

Thickness: 22.9 mm 32 ”190 g atro 6.76 g1.9 g

Thickness: 22.3 mm 42 "190 g atro 8.45 g1.9 g Thickness: 15.4 mm 42" I90 g atro 8.45 g1.9 g

Thickness: 17.6 mm 42 ”190 g atro 8.45 g -8 '+ 0.5% Furtofix P3 pH value for return water 6.5ρΗ 6.4

Density: 245 kg.m ”^ o

Flexural strength: 16.4 kp.cm ** Water intake: 21.6% Example 18

Solid fiber grinding degree + 1.6% BVR-5O + 0.5% Furtofix P3pH value for return water 6.5pH 6, 5

Density: 249 kg.m ”^

Flexural Strength: 16.9 kp.cmWater Intake: 27.7% Example 19

Solid fiber Fill grade + 1.6% BVF-50 + 0.5% Furtofix P3 pH value for return water 5.7

pH

Density: 250 kg.m ** ^ -2

Flexural Strength: 18.4 kp.cmWater Intake: 15.3%

Thickness 17.1 mm 1.9 g 42 "190 g. Atro 6.7b g 1.9 g

Thickness: 17.3 mm 42 "190 g and 6.76 g1.9 g

Thickness: 17.1 mm In addition to the above examples, it should be noted that in Examples 10 to 19, as is also indicated in the accompanying flow diagram, "backwater" was used.

The hydrophobized fiber boards listed in Examples 12 to 19 have different and partially high water intake values, non-bot fiber composition consists of 50% Fi.Hg.i.R (foreign), 40% Fi.Sp.i.R. and 10% larch, and it is not possible to avoid partial high accumulation of larch and thus increased water intake.

Claims (7)

ŇHtoS VŠETEČKAadvokát 5íjg ^ 4 PRAHA 1, Ž? 'Rrá 25 ~ 9 ~, PATENTOVÝ NÁROJE A hydrophobised fiberboard comprising a resin-free hydrophobic agent, characterized in that the hydrophobizing agent is present in the plate at a maximum of 5% by weight, preferably 2% by weight, based on the wood fiber, and that the hydrophobizing agent is fixed to the individual wood fibers. fixative. 2. A hydrophobised fiberboard according to claim 1, wherein the fixing agent is an organometallic compound. 3. A hydrophobised fiberboard according to claim 2, wherein the fixing agent is an oligomeric condensate of aluminum dicyandiamide. 4. Hydrophobised fiberboard according to claim 1, characterized in that the fixing agent is a dispersion of reinforced natural resins. 5. Hydrophobised fiberboard according to any one of claims 1 to 4, characterized in that the fixing agent is applied to the wood fiber in the form of an aqueous solution. 6. A hydrophobized fiberboard according to any one of claims 1 to 5, wherein the hydrophobizing agent is supported in the form of an aqueous dispersion of crosslinked natural resins with 45% by weight solids. 7. A process for the production of a hydrophobised fiberboard comprising a resin-free hydrophobizing agent by a wet process, characterized in that a resin-free hydrophobic agent is added to the wood fibers in an amount of at most 5% by weight, preferably 2% by weight, based on the wood. the fiber, and then the fixative is added and mixed with the wood fibers and with the hydrophobizing agent to fix the hydrophobic agent on the individual fibers and that, optionally, after the temporary storage, 1 fiber mat is formed from the hydrophobised wood fibers and further processed on a fiberboard. Represents: