RU2486053C2 - Composition for making bioresistant particle board - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition for making bioresistant particle board contains wood particles, chromium-copper antiseptic, paraffin, resin-containing binder and a composite hardener. The resin used is formaldehyde resin. The composite hardener used is a mixture of ammonium dichromate, ammonium chloride and polyoxyethylene alkylphenyl ether.

EFFECT: high efficiency of the composition for making bioresistant particle board.

4 tbl, 1 ex

Description

The invention relates to the woodworking industry, relates to the manufacturing technology of wood composite materials and can be used in the manufacture of biostable chipboards (chipboard-b).

A known composition for the manufacture of chipboard-b, in which the urea-formaldehyde resin (CFS) contains a 40% solution of copper sulfate in an amount of 17.5 wt.% Salt from abs. dry pitches. A mixture of carbamide and copper sulfate mixed at a molar ratio of 1: (0.125-1) is applied to both sides of the formed carpet and pressed at a temperature of 115-130 ° C and a specific pressure of 2 MPa for 0.40-0.65 min / mm thickness of the finished plate. The amount of copper sulfate introduced into the plate with a binder and coating meets the biostability criteria for wood products [patent (RU) No. 2209819, publ. 08/10/2003].

A disadvantage of the known technical solution is the need to create a high concentration of the binder, the presence of urea in the chip-adhesive composition will lead to the need to increase the duration of pressing plates.

In another composition for the manufacture of chipboard-b, a KFS hardener is used, containing ammonium chloride and copper sulfate in a mass ratio (15-25) :( 75-85). The hardener is used in an amount of 0.6-1.0 wt.% By weight of the plate [and.with. USSR No. 421531, publ. 03/30/1974].

A disadvantage of the known technical solution is that the presence in the composition of the combined hardener of copper sulfate, the aqueous solution of which has an acidic reaction, leads to hydrolytic destruction of the urea-formaldehyde polymer during prolonged exposure to conditions with variable temperature and humidity.

A composition is also known, which includes a hardener for KFS, which is a mixture of iron (III) salt and ammonium chloride in a mass ratio (0.2-2.0): 1, which allows to reduce the curing time of the binder in 2.0-2, 5 times. Using this hardener, the chipboard pressing process is carried out at a reduced temperature of 120-180 ° C for 0.15-0.55 min / mm of the thickness of the finished plate [a.s. USSR No. 823167, publ. 04/23/1981].

A disadvantage of the known technical solution is that since iron salts have pronounced redox properties, the presence of this compound can cause oxidative degradation of the cured binder. In addition, the viability of this composition is reduced compared with the binder on a standard hardener, which creates technological difficulties in the manufacture of plates.

Another composition for modifying chipboard includes synthetic fatty alcohols, sodium tetraborate, boric acid and water in a weight ratio of (30-50) :( 1-10) :( 2-42) :( 1-66). The composition is introduced into CFS in an amount of 15-20 wt.% From abs. dry resins with a concentration of 60% [and.with. USSR No. 485887, publ. 09/30/1975].

A disadvantage of the known technical solution is that the presence in the system of sodium tetraborate and boric acid, which together form a buffer system, creates conditions for slowing down the process of polycondensation of the binder.

Closest to the proposed invention is a composition for the manufacture of chipboard-b [and.with. USSR No. 1071450, publ. 02/07/1984 - prototype]. According to the author’s certificate, ammonium silicofluoride in the amount of 1.65-2.90 wt.% From abs. dry pitches. The hardener is introduced into the resin in the form of a 20% solution. CFS consumption is 8.1-11.7 wt.% Of abs. dry wood. Wood chips, dried to a relative humidity of 5-6%, are mixed with a binder. The moisture content of the chip-adhesive mixture is 8-12%. Pressing is carried out at a temperature of 170 ° C, a specific pressure of 2.5 MPa and a duration of 0.35 min / mm of the thickness of the finished plate. The resulting chipboard-b meets the requirements of GOST 10362-2007. With a decrease in the content of ammonium silicofluoride less than 1.65 wt.%, There is a deterioration in the physicomechanical parameters of DSP-b, and with an increase in its consumption of more than 2.90 wt.%, The properties of the plates are maintained at the same level.

Known technical solution has the following disadvantages. In the process of pressing and operating DSP-b, hydrogen fluoride is emitted, which creates environmental problems. In addition, ammonium silicofluoride is inaccessible and has a high cost.

The technical task of the invention is to increase the efficiency of the composition for the manufacture of biostable chipboards by providing the possibility of obtaining chipboard-b, corresponding in its physical and mechanical parameters to the requirements of GOST 10632-2007, classified as bio-resistant according to the method described in the source [Gorshin S.N. Wood preservation. - M .: Forest. industry, 1977. - S.95-97] as related to biostable materials, subject to hot pressing at a temperature of 180-200 ° C and increasing the bonding strength of wood particles.

This goal is achieved by the fact that in the composition for the manufacture of biostable chipboards containing wood particles, a chromomedy antiseptic, paraffin, formaldehyde resin (FS) and a combined hardener (KO), including ammonium dichromate, ammonium chloride and polyoxyethylene alkyl phenyl ether (POEAFE, wood) additionally contain a chromo-copper antiseptic, and the binder as a resin contains FS and additionally - KO. The composition can be made, for example, in the following ratio of components, parts by weight (by abs. dry substances):

Wood particles (abs. Dry.) one hundred Chromomed antiseptic by mass abs. dry wood 3.5-4.5 Paraffin by mass abs. dry wood 0.8-1.2

Formaldehyde resin by weight of abs. dry wood:

for outer layers 12-16 for the inner layer 9-12

Ammonium dichromate by weight of abs. dry resin:

for outer layers 0.37-1.86 for the inner layer 3.34-4.76

Ammonium chloride by weight of abs. dry resin:

for outer layers 0.13-0.60 for the inner layer 1.09-1.67

POEAFE by mass abs. dry resin:

for outer layers 0.006-0.042 for the inner layer 0,071-0,089

The invention has the following differences from the prototype:

- wood particles additionally contain a chromomed antiseptic;

- the binder as a resin contains formaldehyde resin and optionally a combined hardener;

- the combined hardener contains ammonium dichromate, ammonium chloride and polyoxyethylene alkyl phenyl ether.

The composition can be made in the following ratio of components, parts by weight (by abs. dry substances):

Wood particles (abs. Dry.) one hundred Chromomed antiseptic by mass abs. dry wood 3.5-4.5 Paraffin by mass abs. dry wood 0.8-1.2

Formaldehyde resin by weight of abs. dry wood:

for outer layers 12-16 for the inner layer 9-12

Ammonium dichromate by weight of abs. resin:

for outer layers 0.37-1.86 for the inner layer 3.34-4.76

Ammonium chloride by weight of abs. dry resin:

for outer layers 0.13-0.60 for the inner layer 1.09-1.67

POEAFE by mass abs. dry resin:

for outer layers 0.006-0.042 for the inner layer 0,071-0,089

The effect lies in the combined action of the three components of CO. Ammonium chloride creates the acidity necessary for the curing of PS and at 105 ° C, corresponding to the temperature of the inner layer of the plate, it is supplemented by the acidity of ammonium dichromate. At temperatures above 168 ° C, ammonium dichromate decomposes exothermically, which causes a deepening of the curing of the PS and leads to a decrease in the acidity of the medium, which, in turn, helps to reduce the thermal degradation of the cured polymer. POEAFE helps to improve the spreading of PS on the surface of wood antiseptic particles and thereby compensates for the decrease in their wetting ability.

This will increase the efficiency of the composition for the manufacture of biostable chipboards by providing the possibility of obtaining chipboard-b, corresponding in their physical and mechanical parameters to the requirements of GOST 10632-2007, biostability classified as related to biostable materials, subject to hot pressing at a temperature of 180- 200 ° C and increase the bonding strength of wood particles.

The advantages of the proposed composition in comparison with the prototype are due to the lack of emission of hydrogen fluoride from the plates both during production and in operating conditions due to the fact that this composition does not contain fluorine-containing components. The resulting plates have increased strength and water resistance due to the use of ammonium dichromate, which inhibits the hydrolytic destruction of the cured polymer. In addition, due to the oxidative activity of ammonium dichromate, which converts formaldehyde in hot pressing into water and carbon dioxide, the emission of formaldehyde from the plates is reduced.

In the patent information fund we reviewed, no similar technical solutions, as well as technical solutions containing the indicated features, were found.

The invention is applicable and will be used in the industry in 2011.

The applicants note that their claimed composition for the manufacture of biostable chipboards is under investigation and testing, i.e. the quantitative composition is still approximate, confirms the reality of obtaining the composition with the specified quantitative composition, therefore, it is indicated in the second claim.

For the manufacture of the composition used the following materials:

Wood particles with a moisture content of 60%;

Potassium dichromate (GOST 4220-75);

Copper sulfate (GOST 4165-78);

Solid petroleum paraffin (GOST 23683-89);

Formaldehyde resin, for example, industrial grade urea-formaldehyde resin KF-MT-15, 68% solution (TU 6-06-12-88);

Ammonium dichromate (GOST 3763-76);

Ammonium chloride (GOST 3773-82);

Polyoxyethylene alkylphenyl ether (GOST 8433-81).

The composition for the manufacture of biostable chipboard was prepared as follows.

EXAMPLE 1

The composition was prepared by converting all components to abs. dry substances. On wood particles with a moisture content of 60% in an amount of 100 parts by weight abs. dry wood by pneumatic spraying applied a 10% solution of chromomered antiseptic in an amount of 4.5 wt.%. from abs. dry wood. The chromomedic antiseptic contained potassium dichromate and copper sulfate in a mass ratio of 1: 1. Wood particles were fed for drying, where they were dried to a moisture content of 3%, after which paraffin was applied to the chips in an amount of 0.8 wt.%. from abs. dry wood, and then filed for sorting in layers. The mass ratio of the outer and inner layer was 2: 3. The binder for the outer layer included formaldehyde resin (FS) in an amount of 16 wt.% From abs. dry wood of the outer layer, as well as ammonium dichromate in an amount of 1.47 wt.% from abs. dry FS of the outer layer and POEAFE in the amount of 0.028 wt.% From abs. dry FS of the outer layer. The binder for the inner layer included PS in the amount of 12 wt.% From abs. dry wood of the inner layer, as well as ammonium dichromate in an amount of 6.38 wt.% from abs. dry FS of the inner layer and POEAFE in an amount of 0.120 wt.% From abs. dry FS of the inner layer.

Wood particles were mixed with a binder in layers and sent to form a packet. The finished chip package was pressed and then pressed in a hot press at a temperature of 200 ° C, a specific pressure of 2.4 MPa and a specific pressing time of 0.35 min / mm of the finished plate. After pressing, the plates were conditioned at a temperature of 20 ± 2 ° C and a relative humidity of 65 ± 5% for 5 days. Finished boards were tested according to GOST 10634-88, GOST 10635-88, GOST 10636-90, GOST 27678-88 and the method described in the source [Gorshin S.N. Wood preservation. - M .: Forest. industry, 1977. - S.95-97].

Table 1 presents the composition in wt.h. by examples in abs. dry substances).

Table 1 The composition of the composition according to the examples (abs. Dry. Substances) Components Component Content by examples, parts by weight one 2 3 four 5 6 7 Wood particles one hundred one hundred one hundred one hundred one hundred one hundred one hundred Chromomed antiseptic by mass abs. dry wood 4,5 4,5 4.0 4.0 4.0 3,5 3,5 Paraffin by mass abs. dry wood 0.8 0.8 1,0 1,0 1,0 1,2 1,2 FS by mass abs. dry wood: - outer layer 16 16 fourteen fourteen fourteen 12 16 - the inner layer 12 12 10 10 10 9 12 (NH ₄ ) ₂ Cr ₂ O ₇ by weight abs. dry resin: - outer layer 1.47 0.37 0.74 1,11 1.48 1.86 0.24 - the inner layer 6.38 4.76 3.69 4.06 4.43 3.34 2.20 NH ₄ Cl by weight of abs. dry resin: - outer layer 0.00 0.13 0.25 0.37 0.49 0.60 0.24 - the inner layer 0.00 1,67 1.23 1.35 1.48 1.09 2.20 POEAFE by mass abs. dry resin: - outer layer 0,028 0.006 0.015 0,022 0,030 0,042 0.011 - the inner layer 0,120 0,071 0,074 0,081 0,089 0,075 0,099

Table 2 presents the recipes for the manufacture of chipboard-b according to the examples, based on the receipt of one sample of a plate 400 × 400 mm in size, 16 mm thick and a density of 700 ± 12 kg / m ³ .

Table 3 presents the consumption of components for the preparation of 1000 kg of a 20% solution of KO.

table 2 The formulation of chipboard-b Components Component Consumption by Examples one 2 3 four 5 6 7 Wood particles with a moisture content of 60%, g 2270 2270 2320 2320 2320 2360 2290 Chromium antiseptic, 10% solution, g 640 640 580 580 580 510 500 Paraffin, g 11,4 11,4 14.5 14.5 14.5 17.7 17,2 FS, 68% solution, g: - outer layer 131 131 117 117 117 102 132. - the inner layer 153 153 130 130 130 118 153 KO, 20% solution, g: - outer layer 6.7 2.2 4.0 6.0 8.0 8.7 2.2 - the inner layer 33.7 33.7 22.1 24.3 26.5 18.1 23.5

Table 3 Consumption of components for the preparation of 1000 kg of a 20% solution of KO, kg Components Examples one 2 3 four 5 6 7 (NH ₄ ) ₂ Cr ₂ O ₇ 196 147 148 148 148 148 98 NH ₄ Cl 0 51 49 49 49 48 98 POEAFE 3,7 2.2 3.0 3.0 3.0 3.3 4.4 Water 800 800 800 800 800 800 800

Table 4 presents the physical and mechanical properties of chipboard-b.

Table 4 Physico-mechanical properties of chipboard-b Indicators Examples one 2 3 four 5 6 7 Destructive stress during static bending, MPa 8.1 13.5 13.0 14.0 12.7 13.1 9.6 Tensile stress tensile perpendicular to the plate face, MPa 0.18 0.32 0.34 0.43 0.36 0.35 0.30 Thickness swelling in 24 hours,% 42.3 24.2 21,2 18.2 23,2 22.5 34.5 Thickness swelling in 14 days,% 82.0 45.4 38,4 32,4 37.8 42.3 76,4 Formaldehyde emission, mg / 100 g plate 14.6 8.2 7.4 7.2 7.6 8.0 13.6 The weight loss of the sample when tested for biostability,% 2.7 2,8 3.2 3,1 3.3 3.6 3,5

Tests of finished boards showed that the invention allows to obtain particle boards with physico-mechanical properties that meet the requirements for chipboard according to GOST 10632-2007, which are biostable (weight loss during testing less than 5%) and having an emission class of formaldehyde E1 (formaldehyde content less than 8 mg / 100 g of plate). In the manufacture of chipboard-b according to example 4, the plates are characterized by optimal performance in relation to the basic physical and mechanical properties and meet the requirements for chipboard grade P-A according to GOST 10632-2007. In the manufacture of chipboard-b according to examples 3 and 5, the boards comply with the requirements for chipboard grade П-Б according to GOST 10632-2007.

Thus, the use of the invention will improve the efficiency of the composition for the manufacture of biostable chipboards by providing the possibility of obtaining chipboard-b, corresponding in its physical and mechanical parameters to the requirements of GOST 10632-2007, biostability classified as related to biostable materials, subject to hot pressing at a temperature of 180-200 ° C and increase the bonding strength of wood particles.

Claims (1)

Composition for the manufacture of biostable chipboards, characterized in that it includes wood particles, a chromomedy antiseptic, paraffin, a binder containing a resin and a combined hardener, while a formaldehyde resin is used as a resin, and a mixture of ammonium dichromate, ammonium chloride is used as a combined hardener and polyoxyethylene alkyl phenyl ether, the composition is manufactured in the following ratio of components, parts by weight (by abs. dry substances):
Wood particles (abs. Dry.) one hundred Chromomed antiseptic by mass abs. dry wood 3.5-4.5 Paraffin by mass abs. dry wood 0.8-1.2 Formaldehyde resin by weight of abs. dry wood: for outer layers 12-16 for the inner layer 9-12 Ammonium dichromate by weight of abs. dry resin: for outer layers 0.37-1.86 for the inner layer 3.34-4.76 Ammonium chloride by weight of abs. dry resin: for outer layers 0.13-0.60 for the inner layer 1.09-1.67 Polyoxyethylene alkyl phenyl ether by weight of abs. dry resin: for outer layers 0.006-0.042 for the inner layer 0,071-0,089