JPH03281202A - Preparation of particle board - Google Patents

Abstract

PURPOSE:To get rid of decrease in various physical properties such as adhesive strength, to shorten heat-pressing time and to improve productivity by using a delayed curing type amino resin to wooden chips for surface and rear face layer parts and a fast curing type amino resin to wooden chips for a core layer part. CONSTITUTION:Each of wooden chips for surface and rear face layer parts and a core layer parts is stirred and mixed while each part is sprayed with a amino resin to coat uniformly and evenly therewith and the rear layer part, the core layer part and the surface layer part are successively laminated in this order to obtain a laminated body, which is then heated and compressed to prepare a particle board. A delayed curing type amino resin is used for the wooden chips for the surface and rear layer parts and a fast curing type amino resin is used for the wooden chips for the core layer part. As the delayed curing type amino resin adhesive, a urea resin content of 45-60 wt.% and a molar ratio (F/U) of urea (U) and formaldehyde (F) which are main ingredients of 1.0-1.5 is used. In addition, as the fast curing type amino resin adhesive, a urea resin with a resin content of 60-70 wt.% and a molar ratio (F/U) of urea (U) and formaldehyde (F) which are main ingredients of 1.2-2.0 is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a particle boat manufactured using an amino resin.

More specifically, the present invention relates to a method for producing Particle Bo F using a 71-liquid amino resin that improves productivity and shortens heat-pressing time.

[Conventional technology]

Conventionally, the curing time of the compounded resins in the multilayer particle board is adjusted by changing the proportion of the compounded components of the same resin, the amount of curing agent added, etc. ing.

For example, when blending the amino resin in the wood chips on the front and back layers of a three-layer particle board, no curing agent is added in order to prevent thermal deterioration since the wood chips are in direct contact with the heating plate.
Alkali catalysts and organic amino catalysts have been added to delay curing time and prevent thermal deterioration.

In addition, the heat transfer rate of the core layer is slower than that of the front and back layers, so in order to compensate for the delay in heat transfer time, the curing speed with the front and back layers is adjusted by adding the maximum amount of curing agent that will accelerate curing. was doing.

In this way, the method of using the same resin for the amino resin of the wood chips in the front and back layers and the core layer and adjusting the curing time depending on the blended components can improve the productivity of particle holes, which are becoming increasingly requested by users year by year. I couldn't cope anymore.

That is, when the temperature of the hot plate is raised for the purpose of shortening the hot pressing time, it is difficult to achieve the objective because it cannot cope with thermal deterioration of the front and back layer parts and rapid hardening of the core layer part.

[Problem to be solved by the invention]

The present inventor has solved these problems, shortened the hot pressing time, and significantly improved productivity.

In other words, by using two-component amino resin adhesives, each with unique properties, for the front and back layers and the core layer, thermal deterioration of the front and back layers can be prevented, and the core layer can harden quickly. The above-mentioned problem was solved.

[Means to Solve the Problem] In view of the above situation, the present inventors sprayed the wood chips on the front and back layers and the core layer using a conventional one-component resin. It was found that this method could no longer be expected to shorten the heat-pressing time.

In view of this situation, the present inventors developed a two-component amine resin for the front and back layer parts and the core layer part, giving each of them unique characteristics, preventing thermal deterioration of the front and back layers, and still maintaining the core layer. It is a two-component amino resin that has quick curing properties in the layered parts and can shorten the heat-pressing time.

That is, when using wood chips for the production of particle board, the present invention sprays amine resin on each of the wood chips for the front and back layers and the core layer while stirring and mixing, and applies the resin evenly and evenly. A method for producing particle board by sequentially laminating a back layer, a core layer, and a surface layer to obtain a laminate, and heating and compressing the laminate, wherein the wood chips for the front and back layers are delayed hardened. mold amino resin,
A method for producing a particle board using a fast-curing amino resin as a wood chip for the core layer, wherein the resin content of the slow-curing amino resin is 45 to 5 Qwt%, and the main component is urea (U). ) and formaldehyde i'(F) urea resin with a nomolar ratio (r'/U) of 1.0 to 1.5,
The resin content of the fast-curing amino resin is 60 to 70 wt%, and the main components are urea (U) and formaldehyde (F).
) is characterized by being a urea resin having a molar ratio (F/11) of 1.2 to 2.0. Furthermore, melamine (M
) and formaldehyde (1') molar ratio (F/M)
5.0 to 20.0 of the urea-melamine cocondensation resin.

The present invention will be described in detail.

The delayed curing amino resin adhesive of the present invention has a resin content of 45 to
The molar ratio (F/
A urea resin having U) of 1.0 to 1.5 is used.

In addition, melamine (Vl') and formaldehyde
+') molar ratio (F/M) of 5.0 to 20.0 -
Melamine cocondensation resins may also be used.

In addition, fast-curing amino resin adhesives have a resin content of 60 to 70.
The main components are urea (b) and formaldehyde (wt%).
A urea resin having a molar ratio (F/U) of F) of 1.2 to 2.0 is used. Furthermore, a urea-melamine cocondensation resin having a molar ratio (P/M) of melamine (M) and formaldehyde (F) of 5.0 to 20.0 may be used.

The laminate is made by spraying amino resin on each of the wood chips for the front and back layers and for the core layer, stirring and mixing them, applying them evenly and evenly, and then applying the amino resin to the wood chips for the front and back layers and the core layer in the order of the back layer, core layer, and surface layer. Laminate them progressively to form 3 layers (1. When to heat and compress the 1st step).

Usually, the adhesive used to manufacture Percycle Ball 1 is molded, and the resin content of the adhesive is usually 60%.
~70% is used. This is done by spraying the wood chips on the front and back layers and the core layer using the same glue.
It is commonly used as an amino resin for

, v, The resin compound composition sprayed on the surface part is used during heat molding of particle board! tJI curing is required, and in order to prevent the adhesive layer from being destroyed (commonly called a "bank") due to the vapor pressure generated due to the internal temperature rise after the adhesive strength is developed, It is necessary to maintain the moisture content as much as possible, and also to maintain a viscosity that is suitable for spraying, and usually has a resin content of 60 to 70%.
It is set up to suit your needs.

Therefore, the adhesive for the front and back layer parts is the same resin content as the heat molding part 11.1 and the core layer part.
・No〃) Apply conduction promotion to To1 Otokogi + A quality chip?
In order to make the total water content after ladle (called mantle water content) higher than that of the core layer, it is generally necessary to increase the amount of water added to the blended composition.

In order to meet the demand for shortening heat pressing time with the aim of increasing productivity every year, it has become difficult for resin adhesives to respond to the rise in hot plate temperature and the rapid curing of resin adhesives. What is happening is as mentioned above.

In the present invention, for the front and back layers, the resin content is 45 to 60%.
Using a urea resin with a molar ratio (F/U) of urea (U) and formaldehyde l'(1') of 1.0 to 1.5, and a molar ratio of melamine 01) and formaldehyde (F) It has been found that using a urea-melamine cocondensation resin having an F/M ratio of 50 to 20.0 is effective in delaying the hot pressure time.

If the resin content is less than 45%, various physical properties such as the bending strength, bending Young's modulus, and surface IJ separation strength after thermosetting of the GJ front and back layers will decrease, and if it is more than 60%, the curing retardation effect will be poor. Undesirable. Particularly in the current situation where the heat pressure temperature during production of Particle Ho 1 is increasing year by year, it has been found that it is difficult to satisfy the above physical properties with an adhesive with a resin content of 60% or more in order to prevent thermal deterioration. 7.6 The present invention can be used to bond #Al1Fi manufactured with a resin content of 60% or more. ii ζ 2 and water) j I + E, and the resin content is 45 to 45 for the front and back 16 parts (i 0% It turned out that it could not be done.Is the reason for the stiffness certain?-Is there no C?The same condensation rate (45-
I don't think this is because the structure in heat curing is different for 60% resin adhesive.

In addition, a two-hour delay was carried out to increase the temperature of the molar ratio (
1/IJ) and the addition of urea, melamine, other alkali-11 metal salts, and amines at the time of formulation can also provide this function as curing retardation.
In either case, the above-mentioned per-cycle properties (1) deteriorate and there are (2) problems.

Therefore, we seek the optimum physical properties of particle holes, and par)
- For Ikurupo / Released from Pol J -, Azuki -) What 21
・The molar ratio (F/Ll) is 1.0 under the optimal conditions.
~ 1.5 If the molar ratio is too high, more than 1.0 will result in a significantly low bending strength, bending A・〉'g ratio, and surface 711 separation strength of -9, and if it is more than 1.5, particles will be generated. Formaldehyde released from Ho 1 meets the Japanese Agricultural Standards F-2 standard (5
This is not desirable because it is impossible to create a model that satisfies the requirements (p4 or less).

Further, although the addition of melamine powder has a considerable effect on curing delay, it is not preferable because it has poor solubility in water and may not precipitate in the blended composition. Furthermore, alkali metal salts tend to cause undercuring, making it difficult to adjust pot life.

Particle Ho IS is often required to be water resistant. In order to maintain the water resistance, the molar ratio (F/M) of melamine and formaldehyde is 15.0 to 20.0.
A molar ratio of less than 5.0 moles results in poor performance of the above-mentioned physical properties, and a molar ratio of more than 20.0 moles is not preferred because it is economically disadvantageous.

The resin adhesive for the core layer portion preferably has a molar ratio (F/11) of 1.2 to 2.0, more preferably 1.3 to 1.0, in order to provide fast curing properties. It is 6. 1.2
In the following F, it is not possible to make the thermal pressure 11.5 seconds or less for the IV diameter 1 m/I11 of the Bakkeikurubo-1. In addition, if the particle board is over 2.0, the formaldehyde released by the particle board is F-2.
It is difficult to meet standards.

The resin content of the peripheral portion of the core layer is preferably 60 to 70%,
If it is less than 60%, the water content in the composition becomes high, and layer destruction from the core layer portion called a bank tends to occur, which is not preferable. Moreover, if it is 70% or more, it is not preferable because the resin viscosity cannot be controlled to a level that is higher than the condensation rate of the amino resin that can maintain various physical properties.

Co-condensation of the adhesive with melamine in the present invention is advantageous in terms of physical properties such as water resistance and core peel strength.

Molar ratio of formaldehyde (F) and melamine (M) (F
/gate) is preferably 5.0 to 20.0, more preferably 10.0 to 15.0. If it is less than 5.0, the water resistance performance will deteriorate, and if it is more than 20.0, it will slow down the curing speed, which may lead to a decrease in strength due to undercuring, which is not preferable.

〔Example〕

The present invention will be explained in detail below with reference to Examples.

1 Example 1 Formaldehyde (L), urea (U) and melamine (
After adding and mixing 1 part of wax emulsion (solid content 40%) to 100 parts of a urea-melamine cocondensation resin adhesive with a molar ratio of I:0.8:0.05 and a resin content of 55%, water 3 parts were added to obtain an adhesive composition.

This adhesive composition was applied to wood chips (moisture content 3.0%) 1
A chip for the front and back layers was obtained by spraying and coating 13 parts to 00 parts.

Similarly, the molar ratio of formaldehyde (F), urea (11) and melamine (M) is I:0.75:0. Old resin content 6
Adhesive composition for the core layer part prepared by adding 2 parts of wax emulsion (solid content 40%), 1 part of ammonium chloride, and 0.5 part of 25% aqueous ammonia to 100 parts of a 5% urea-melamine cocondensation resin adhesive. Wood underlay (moisture content 7.0%)
A core layer chip was obtained by spraying 8 parts to 100 parts.

The chips for the front and back layers and the chips for the core layer obtained as described above were laminated alternately to form a three-layer structure of pine 1, and then a hot press was used at a temperature of 170°C, a pressure of 2, and a force of 30 kg. / cnl for 3 minutes to produce particle board with a thickness of 15 mm. Table 1 shows the results of various physical property tests of this particle board.

Example 2 Formaldehyde (F), urea (U) and melamine (
After adding and mixing 1 part of wax emulsion (solid content 40%) to 100 parts of a urea-melamine cocondensation resin adhesive with a resin content of 52% and a molar ratio of M) of ]:0.7:0.01, water was added. 1 part was added to obtain an adhesive composition.

This adhesive composition was applied to this material chip (moisture content 2.5%) 1
A chip for the front and back layers was obtained by applying 13 parts to 00 parts.

Similarly, the molar ratio of formaldehyde (F), urea (U), and melamine (M) is 1:0.7:0.03, and the resin content is 65%.
A core layer adhesive composition prepared by adding 2 parts of wax emulsion (solid content 40%) and 2 parts of ammonium chloride to 100 parts of the urea-melamine cocondensation resin adhesive was mixed with wood chips (
A core layer chip was obtained by spraying 8 parts to 100 parts (water content: 5.0%).

Using this chip, a thickness of 3 A particle board with a diameter of 1.5 mm was obtained.

Table 1 shows the results of various physical property tests of this particle board.

Example 3 Formaldehyde (+'), urea (U) and melamine (M
) has a molar ratio of 1. :0.85:0.05, resin content 58%
After adding and mixing 1 part of wax emulsion (solid content 40%) to 100 parts of the urea-melamine cocondensation resin adhesive, 5 parts of water was added to obtain an adhesive composition.

This adhesive composition was applied to wood chips (water content 3.5%) 1
A surface layer underlayer was obtained by spraying 13 parts to 00 parts.

Similarly, a core layer chip was obtained according to Example 1.

Using this chip, chips for the front and back layers and chips for the core layer were alternately laminated to form a three-layered mat, and then hot pressed at a temperature of 170°C and a pressure of 30kg/c+.
A particle board having a thickness of 15 mm was produced by compressing it for 3 minutes using fl. Table 1 shows the results of various physical property tests of this particle board.

Comparative Example 1 4) 1 part fat content 6501'l, 'Q 3 < tAf fat adhesive 10Q part, 1 part Rin Las-1, 'J1...-3 N (hard resin 1 min, 10%) added and mixed After 7 hours, ε (parts) was added to 7 to obtain an adhesive composition.

Apply 133 parts of N mouth composition to Kizuki nap (moisture content 3.50 <) + 0 part, spray 1J, and apply 1J of 133 parts, and then apply 1J of 133 parts to the front and back layers of chip 4 + i knee 1. is.

In the same I/L, chloride -? Spray 8 parts of adhesive for the core layer mixed with 1 part of 1,000 ml of wood and 0.5 parts of 25% ammonia water to 100 parts of 100 parts of wood (water content: 7.0%). t
jt Nurikin (-1 hiki, I got 10 bu for the face part.

The chips for the front and back layers and the chips for the core layer obtained in step 7 as described in 1.
・Layer the layers in a 7T cross layer to form a layered structure of 751.
0 kg/+ (at d, i min [1 previous shrinkage and temperature 1
70°C 1 pressure crab (OkIN7' (2 types of crabs compressed for 3 minutes and 7 times + 719 x 15mm + 2)
< 1jMury produced - U-Ikurubo-1.

This Verdykle Jζ-1's physical property test results are the first in all.
Table 01 = j kushita.

Comparative Example 2 Bormaldehy 1 (F), urea ([+) and melamine (
The molar ratio of M) is 1:0.75:0. After adding and mixing 1 part of Wanx Emulsion (solid content 40%) to 100 parts of a urea-melamine cocondensation resin adhesive with a resin content of 65%, 8 parts of water was added to obtain an adhesive composition.

4. Apply this adhesive composition to wood. (Quality chips (moisture content 3.5%)
) 13 parts per 100 parts] coated (=t) to obtain 1,000 knobs for the front and back layers.

Similarly, a core layer adhesive prepared by adding 1 part of ammonium chloride and 0.5 parts of 25% ammonia water to 100 parts of a urea resin adhesive with a resin content of 65% was applied to a wood bamboo knob (water content 7.0%).
) Sprayed 8 parts to 100 parts LJ coating A.1 to obtain a core layer depth.

A trowel particle board was manufactured under the same conditions as in Comparative Example 1 using the chips made of this material.

7 Condolence Table 17 - [Effects of the Invention] As described above, the present invention, when producing a multilayer particle board, uses a slow-curing amino resin adhesive for the front and back layers and a fast-curing amino resin adhesive for the core layer. Contains amine resin adhesive of
Using a simple method that does not change in any way from the traditional installation method of spraying and using, each amino resin adhesive has unique characteristics, and the characteristic of using a two-component resin adhesive is that It is something that you have.

The properties of the adhesive can prevent deterioration of the wood-based chimney on the front and back layers of Particleboard, which has been a problem in the past due to the deterioration caused by the hot plate.

Therefore, there is no decrease in adhesive strength or other physical properties, and the hot pressing time can be shortened, resulting in a significant increase in productivity, so the effects on the particle bow F industry are immense.

Claims (1)

[Claims] 1) When wood chips are used to manufacture particle board, amino resin is sprayed on each of the wood chips for the front and back layers and the core layer while stirring and mixing, so that the wood chips are uniformly and evenly distributed. A method of manufacturing particle board by coating the particle board, sequentially laminating the back layer, core layer and surface layer to obtain a laminate, and heating and compressing the laminate, the wood chips for the front and back layers. A method for manufacturing particle board using a slow-curing amino resin for the core layer and a fast-curing amino resin for the wood chips for the core layer. 2) Resin content of delayed curing amino resin is 45 to 60 wt%
The main components are urea (U) and formaldehyde (
The method for producing particle board according to claim 1, wherein the urea resin has a molar ratio (F/U) of F) of 1.0 to 1.5. 3) The resin content of the fast-curing amino resin is 60 to 70 wt%, and the main components are urea (U) and formaldehyde (F).
2. The method for producing particle board according to claim 1, wherein the urea resin has a molar ratio (F/U) of 1.2 to 2.0. 4) Molar ratio of melamine (M) and formaldehyde (F) in slow-curing amino resin and fast-curing amino resin (
The method for producing particle board according to claims 1 to 3, wherein the urea-melamine cocondensation resin has a F/M) of 5.0 to 20.0.