CN1058166A

CN1058166A - The processing method of cross section hard wooden floor block

Info

Publication number: CN1058166A
Application number: CN 90104783
Authority: CN
Inventors: 单晓革
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-07-17
Filing date: 1990-07-17
Publication date: 1992-01-29

Abstract

The processing method of cross section hard wooden floor block is that a kind of the employing infiltrated liquid carries out impregnation process to timber technology.It is that the cross section hard wood is placed the pH value is 2～5 or 9～13 urea: the aqueous solution of formaldehyde=1: 1.53～4.17 (weight ratio) was handled after 20～120 minutes ageing 48～72 hours, when containing moisture in 20% left and right sides, timber uses paraffin again under 60～120 ℃ temperature dry 2～3 hours, the wood chip annual ring clear patterns of gained, color are lucid and lively, water content is below 3%, and do not ftracture.Adopt the present invention can make shorten to 2～3 days the arid cycle of timber by 10～15 days.

Description

The processing method of cross section hard wooden floor block

The present invention relates to the impregnation of timber treatment process, particularly to the processing of cross section lignum vitae plate.

When the hard wooden unit of dry cross section, because heating causes a large amount of dehydrations, therefore wooden molecular structure can change, and produces very big local stress, thereby causes the cracking along the wood fibre direction.Need just can adopt the further drying of paraffin to make timber not ftracture with the drying of wood to moisture below 13% for this reason.This method production cycle is long, and occupied ground is big.University teaching material (chemistry of forest product) introduction that also has data such as forestry institute, Nanjing to write is adopted and is handled as timber cross linking agents such as melamine, polyvinyl alcohol, epoxy resin, phthalic anhydride, acetic anhydride, phenol formaldehyde (PF) solution, its weak point is that the timber cost after handling is too high, costs an arm and a leg.

In view of above-mentioned weak point of the prior art the object of the present invention is to provide a kind of processing method with cheap cross linking agent processing cross section lignum vitae plate, make it to shorten arid cycle, show a year wheel pattern.

Purpose of the present invention can realize by following measure: the processing method of cross section hard wooden floor block is that a kind of the employing infiltrated liquid carries out impregnation process to timber technology, it is to place maceration extract to handle after the paraffin drying is used in ageing again the cross section hard wood, it is characterized in that:

The a dipping

ⅰ maceration extract: to urea: the pH value that adds the water of 0.2～0.4 times of amount in the mixed solution 36% formalin=1: 1.53～4.17(weight ratio) and make solution at 9～13 required NaOH or the pH value that makes solution at 2～5 required sulfuric acid,

The ⅱ time: 20～120 minutes

B ageing 48～72 hours

C paraffin drying: will give heat through the wood chip of ageing and be placed in 60～100 ℃ of paraffin dry 1～2 hour to 60 ℃, heating up then keeps half an hour at 100～110 ℃, is warmed up to 110～120 ℃ again and keeps half an hour.

The optimum condition of its dipping is:

ⅰ maceration extract: to urea: the pH value that adds the water of 0.2～0.3 times of amount in the mixed liquor 36% formalin=1: 2.21～2.77(weight ratio) and make solution at 9～13 required NaOH or the pH value that makes solution at 2～5 required sulfuric acid,

The ⅱ time: 30～60 minutes

Method brief description of the process of the present invention is as follows:

Wood chip → dipping → ageing → wax is done → processing → finished product

Dipping is that the blank with cross section hardwood flooring piece is the process of taking out after wood chip places the mixed aqueous solution of formaldehyde and urea to keep the regular hour in above-mentioned flow process.Wooden molecule is a polyol, generally represents with R-OH.It can with formolite reaction, reaction equation is as follows:

Making cross linking agent because of the formaldehyde molecule chain is short with its etherificate can only react on the adjacent hydroxyl with molecule, therefore adds urea, and the aqueous solution of urea and formaldehyde reaction with same mole under acidity or alkali condition can be undertaken by following reaction equation:

The molecule of the Oxymethurea that above-mentioned reaction generates only has a hydroxyl and wooden molecular action, its other end-though but N-H etherificate reaction speed is extremely slow, if in above-mentioned reaction the excessive then Oxymethurea of formaldehyde can further to react its reaction equation again with excessive formaldehyde as follows:

The dimethylolpropionic urea that generates is very easily diffusion in wooden molecule, its strand has a hydroxyl than an Oxymethurea molecular chain length and every end, therefore can after dehydration, link up with the hydroxyl in the wooden molecule, become good cross linking agent, but the mol ratio of formaldehyde and urea was above 2: 1 o'clock, dimethylolpropionic urea can further generate three Oxymethureas again, and same three Oxymethureas also have etherification.Because interlinkage only needs two hydroxyls, and interlinkage in two very approaching i.e. generations of hydroxyl is arranged in three Oxymethureas, act on also little.Thereby the mol ratio of urea and formaldehyde is 1: 1.1～3.0 comparatively suitable.But preferably 1: 1.6～2.0 is comparatively desirable.For making things convenient for practical operation that mol ratio is converted into weight ratio, and the concentration of formaldehyde is in 36%, and then above-mentioned two ratios are respectively 1: 1.53～4.17 and 1: 2.21～2.77.

Because wooden molecule is a polyol, a plurality of hydroxyls are all participated in reaction simultaneously, and it is vital controlling its adsorbance to maceration extract active ingredient.The concentration of this adsorbance and urea, formaldehyde and the time of dipping are closely related.For the mixed liquor that makes urea and formaldehyde is homogeneous phase, needs in it, to add an amount of water and make the urea dissolving.When the low water yield that promptly adds of impregnation concentration more for a long time, the maceration extract active ingredient in the unit volume does not seldom have the cross linking agent of sufficient amount and wooden molecule to carry out etherification reaction after timber absorption.And the concentration of maceration extract can consume the active ingredient of maceration extract more for a long time in a large number and causes and excess reaction not only cause waste, also can cause wooden color and luster too dark.The general water yield that adds is 0.2～0.4 times (weight) of urea and formaldehyde mixed solution weight.And preferably 0.2～0.3 times (weight).

The time of dipping is also relevant with the adsorbance of wooden molecule.Maceration extract is diffused in the wooden molecule needs the regular hour, and the time cross linking agent of too short wooden Molecular Adsorption is not enough, maybe can not be diffused at all levels in.But the cross linking agent in the wooden molecule of overlong time is too much, and the maceration extract consumption is big, and the wood chip color and luster after the processing is too dark.Generally 20～60 minutes best results.

The pH value of maceration extract is related to the content of an Oxymethurea and dimethylolpropionic urea.Because the addition reaction of urea and formaldehyde need be carried out this catalyst under the condition that catalyst exists can be inorganic acid such as sulfuric acid, also can be inorganic base such as NaOH.Its catalyst is that acidity or alkalescence all need certain quantity could play catalytic action, thereby pH value can not equal 7.But the quantity of catalyst can not be too many, promptly make pH value super, so not only cause waste but also corrosion timber, generally select PH=2～6 of acid condition to two ends, the PH=8 of alkali condition～13, preferably PH=9～13 during PH=2 during acid medium～5 alkaline mediums.

Ageing in the technological process is with the processing of drying in the shade of impregnated wood chip, the cross linking agent molecule generation etherification reaction that moisture content in it wooden molecule and infiltration in natural evaporation are entered, and its equation is as follows:

Can reach about 20% through moisture content contained in 48～72 hours these wood chips, it can next step paraffin is dry to be handled in order to carry out.

Wood chip after the ageing is placed 60～100 ℃ dry 1～2 hour of paraffin, improves temperature then and handle half an hour, handle half an hour at 110～120 ℃ at last at 100～110 ℃, make moisture content contained in the wooden molecule all vaporization remove.Dehydration is strengthened under the heat effect of melting heat paraffin simultaneously, and the etherificate degree improves, and wooden molecule interlinkage well gets up, and intermolecular active force has increased.And etherification molecule has substituted the part position of dehydration molecule.The result of comprehensive above-mentioned effect has eliminated the big stress that produces in the drying of wood, thereby has improved the breaking resistance of timber under hot conditions.

Content with cellulose, hemicellulose, lignin in the variation timber of annual ring line has nothing in common with each other, and wooden molecular density difference causes degree of absorption all different with the extent of reaction, produces the pattern that changes with the annual ring line thus, and it is clear, lucid and lively.

Embodiment 1

100 parts of urea and 260 part of 36% formaldehyde are mixed with mixed solution, in this mixed solution, add 100 parts of water and an amount of solid sodium hydroxide again, the pH value that makes solution places the toothed oak wood chip then in this solution and flooded 30 minutes 12, takes out the back ageing and makes moisture reduce to 20% in 60 hours.To place 60 ℃ 60# alloy wax dry through giving the toothed oak wood chip that is heat-treated to 60 ℃, and in 1 hour, be warmed up to 100 ℃ and keep being warming up to 110 ℃ after half an hour and keep half an hour again, and be warmed up to 120 ℃ again and keep half an hour and take out.Be processed as the finished product floorboard through shaping.Any surface finish, cylindrical are golden yellow, interior circle is brown, and moisture is below 3%.

Embodiment 2

The water of 100 parts of urea and 220 parts of formaldehyde (36%) and 100 parts is mixed, add an amount of 98% sulfuric acid again, the pH value that makes solution is 2.5.Then the pear wood sheet is placed and do with example 1 the same ageing and wax after dipping took out in 60 minutes in this solution.Be processed as the pink that the finished product floorboard is an any surface finish through shaping, its water content is below 3%.

Embodiment 3

The water of 100 parts of urea and 160 parts of formaldehyde (36%) and 100 parts is mixed, add an amount of 98% sulfuric acid again, the pH value that makes solution is 3.0.Then the elm sheet is placed in this solution and flooded 120 minutes, take out the back and do with example 1 the same ageing and wax.Being processed as the finished product floorboard through shaping is any surface finish sepia, and its water content is below 3%.

Embodiment 4

The water of 100 parts of urea and 410 parts of formaldehyde (36%) and 100 parts is mixed, add an amount of solid sodium hydroxide again, the pH value that makes solution is 11.Then the look wood chip is placed in this solution and flooded 20 minutes, take out the back and do with example 1 the same ageing and wax.Through shaping be processed as finished product floorboard any surface finish, color is brown.Water content is below 3%.

The present invention has following advantage compared to existing technology:

1. when the dried initial moisture of wax being brought up to 20% left and right sides, dry cross section hardwood flooring piece can not produce cracking yet. Make shorten to 2～3 days by 10～15 arid cycle. Bring thus a series of economic benefit, large batch of industrial production is oversimplified, saved heavy manual labor.

Outstanding through the floorboard year wheel pattern that the inventive method is processed, color is lucid and lively, attractive in appearance, has very high decorative value.

Claims

1, the processing method of cross section hard wooden floor block is that a kind of the employing infiltrated liquid timber is carried out the technology of impregnation process, and it is to place maceration extract to handle after the paraffin drying is used in ageing again the cross section hard wood, it is characterized in that:

The a dipping

I maceration extract: to urea: add the water of 0.2～0.4 times of amount in the mixed solution of 36% formalin=1: 1.53～4.17 (weight ratio), and the pH value that makes solution is at 9～13 required NaOH or make the pH value of solution required 2～5

Sulfuric acid,

The ii time: 20～120 minutes

B ageing 48～72 hours

C paraffin drying will be given heat through the wood chip of ageing and will be placed in 60～100 ℃ of paraffin dry 1～2 hour to 60 ℃, and heating up then keeps half an hour at 100～110 ℃, is warmed up to 110～120 ℃ again and keeps half an hour.

2, the processing method of cross section according to claim 1 hard wooden floor block is characterized in that:

ⅰ maceration extract: to urea: add the water of 0.2～0.3 times of amount in the mixed solution 36% formalin=1: 2.21～2.77(weight ratio), and the pH value that makes solution at 9～11 required NaOH or the pH value that makes solution at 3～5 required sulfuric acid,

The ⅱ time: 30～60 minutes.