JPS6063108A - Preparation of particle board - Google Patents

Abstract

PURPOSE:To obtain the titled board easy to release from a hot plate and a metallic mold by a method wherein a hot press and a patch plate are coated with polyisocyanate compound, wax and water and chips coated with polyisocyanate compound are molded in a press. CONSTITUTION:A hot press and a patch plate are coated previously with polyisocyanate compound such as trilene diisocyanate etc., wax having a melting point 60 deg.C are more such as carnauba wax etc. and water. Then, chips coated with polyisocyanate compound are molded by the above-mentioned hot press and a patch plate to obtain the desired particle board. Additionally above chips are preferably covered with wax having the melting point 60 deg.C and more.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for manufacturing particle board that uses a polyincyanate compound as a binder and facilitates release from a hot platen and a mold.

Particleboard made from wood chips has been widely industrialized, and its binders include urea-formaldehyde resin, melamine formaldehyde resin, urea-melamine formaldehyde resin, phenol formaldehyde resin, and melamine phenol formaldehyde resin. Many problems have been recognized, such as its adhesion, water resistance, formaldehyde emission, etc.

On the other hand, isocyanate compounds are also known to be suitable as binders for particle boards due to their excellent adhesive strength, water resistance, and no formaldehyde release.

Particle board using a polyisocyanate compound as a binder is usually made by adding a polyisocyanate compound alone or together with other substances such as water, formalin resin, etc. to wood chips with a moisture content of 0 to 20% by weight. (1) It is manufactured by mixing in a range of 20% by weight using a blender, applying it, and molding it under the same heat and pressure conditions as when using amino resin.
It can be made into a board in about half the heat-pressing time compared to phenolic resin, and exhibits excellent water resistance. (2) It uses less binder than conventional resins, making it possible to lower the specific gravity of the board. (3) Usage (4) It is possible to eliminate formaldehyde emitted from the board.

However, this method has a serious drawback in that the product board strongly adheres to the hot press plate, patch plate, mold, etc. during hot pressing in the particle board manufacturing process, making it difficult to remove the product. Ta. This problem can be avoided by applying an appropriate mold release agent to the heating plate, patch plate, mold, etc. in advance, or by inserting a release sheet between the heating plate and the board. There is a limit to the durability of the mold release agent and the sheet, and in actual industrial production, these methods complicate the manufacturing process and are not suitable for practical use. It is also possible to use a polyincyanate compound as a binder for only the core layer of a three-layer or multilayer particle board, and use a conventional formaldehyde-based resin as a binder for the surface layer in contact with the heating plate; It can no longer be said that the board does not emit formaldehyde. Despite the characteristics of polyisocyanate compounds as excellent binders, the problem of adhesion to hot discs and the like has hindered their application as binders for particle boards.

It was reported by Thomas M. Maloney that the incorporation of formalin-based resin and paraffin wax into particle board to improve water repellency was useful in preventing the board from sticking to caul plates and hot presses. (
'Modern partic-Ieboard a
nd Dry-process Fiberboard
Man-ufacturing” page 401.
(Miller-Freeman Pub, )) However, when a polyisocyanate compound is used as a binder, paraffin wax does not exhibit this effect; It is stated that adhesion to press parts is a serious problem.

As a result of intensive studies by the present inventors to solve the problems when using the above-mentioned polyisocyanate compounds, 2.
Surprisingly, the present invention was achieved by discovering that excellent mold releasability can be obtained by pre-applying (a) a polyisocyanate compound, (b) a wax with a melting point of 60°C or higher, and (C) water. .

That is, in the present invention, when press-molding chips coated with a polyisocyanate compound to produce particle board, a) a polyisocyanate compound, (b) a wax having a melting point of 60° C. or higher, and ( C) A method for producing particle board characterized by applying water.

The polyincyanate compounds used in the present invention include virtually any polyincyanate.

For example 1. Examples include tolylene diisocyanate, methylene diphenyl diisocyanate, polymethylene polyphenyl polyisocyanate (hereinafter referred to as polymeric MDI), naphthylene diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, methylene dicyclohexyl diisocyanate, triphenylmethane triisocyanate, and the like. Also, iso7 produced by the reaction of excess polyisocyanate with hydroxyl-terminated polyester or hydroxyl-terminated polyether
Included are anate-terminated prepolymers, as well as incyanate-terminated prepolymers obtained by reaction of excess polyincyanate with monomers, polyols, or mixtures thereof, such as ethylene glycol, trimethylolpropane or butanediol.

Water obtained with or without adding a silicone-containing surfactant to the product obtained by reacting a compound obtained by adding ethylene oxide or ethylene oxide and propylene oxide to a monofunctional alcohol on the above-mentioned organic polyisocyanate. Includes emulsifiable incyanate compositions.

The wax used in the present invention has a melting point of 6
There are no particular restrictions as long as it is above 0°C, but particularly preferred examples include carnauba wax, hydrogenated human oil, and cellosol 52.
4 (Middle East Yushi Co., Ltd. - Luna Power Sox Emulsion solid content 30 qb), animal-based beeswax, Cellosol 531 (Chukyo Yushi Co., Ltd., beeswax emulsion solid content 50%), petroleum-based product Microwax , Cellosol 967 (manufactured by Chukyo Yushi Co., Ltd., micro wax emulsion solid content: 5 op.%), low molecular weight polyethylene, Polylon 395 (manufactured by Chukyo Yushi Co., Ltd., low molecular weight polyethylene wax emulsion solid content: 3 o%) Slackwanox, and the like.

Although the molecular weight of the low molecular weight polyethylene is not clearly indicated, it is generally preferred to have a molecular weight in the range of 500 to 5,000. Those with a melting point of less than 60° C. cannot be used because there is a risk that the mold release effect will be weakened, although the detailed reason is unknown.

In the present invention, it is necessary to use water together with the polyisocyanate compound and wax in advance for the hot press and the caulking plate. If water is not used, the reaction of the polyisocyanate compound will not proceed sufficiently and the effect of adhering the wax to the metal surface will be weak.

In the present invention, there are no particular limitations on the blending ratio of (a) polyisocyanate compound, (b) wax with a melting point of 60°C or higher, and (C) water, which are applied to the hot press and patch plate in advance. No, but the weight ratio of (a)
:Cb) is preferably in the range of 995:05 to 10:90, more preferably 99:1 to 50:50. The ratio of (a) and (C) is preferably in the range of (a):(c) to 99:1 to 1:99,
More preferably, the ratio is 80:20 to 20:80.

These numerical ranges indicate ranges in which a particularly excellent mold release effect can be expected; however, deviations from these numerical values do not mean that there is no effect at all.

In the present invention, the amount of mold release agent to be applied to the metal surface cannot be absolutely defined as it varies depending on the usage conditions, but usually the total amount of polyisocyanate compound and wax is 0.1 to 1002 per square meter. It is suitable, and more preferably in the range of 0.5 to 201.

In the method of the present invention, (a) a polyisocyanate compound, (b) a wax having a melting point of 60°C or higher, and (C) water,
Although they can be blended at the time of use, (a) and (b) can also be combined in advance. In this case, a method is used in which wax is dispersed in a polyincyanate compound using a liquid ester, as described in, for example, JP-A-57147567.

In the present invention (a) polyisocyanate compound (b)
After applying wax with a melting point of 60°C or higher and (C) water to the hot press and patch plate, heat-treat the bot press and patch plate at 180°C for 1 hour before use.
Approximately 0 m1n is sufficient.

In the present invention, particle board is formed when (a), (b) and (C) are applied to a hot press and a patch plate and the hot press and patch plate are heat-treated before use, or when they are not heat-treated. By spraying a wax having a melting point of 60° C. or more on the chips together with a polyisocyanate compound, the mold releasability of the molded particle board can be further improved. (a) Polyisocyanate compound and Φ applied to the chip in this case
) The ratio of wax having a melting point of 60°C or higher is not particularly limited, but considering the physical properties of the board, it is preferable that the weight ratio is
a): (b) = 99.5: 0.5-50:
It is preferably in the range of 99:1 to zo:sa.

Moisture is required for the reaction of polyisocyanate compounds, and chips usually contain an appropriate amount of moisture, which can fulfill this role. Of course, water may be used in combination with a polyisocyanate compound and a wax having a melting point of 60° C. or higher.

It is of course possible to use a formaldehyde condensation resin or the like in addition to the polyisocyanate compound as a binder for the chip, and in this case as well, the method of the present invention shows extremely excellent mold releasability.

If particle board using a polyisocyanate compound is manufactured by simply applying wax to the hot press or caul plate in advance, the particle board will adhere to the hot press or caul plate, making it impossible to obtain a normal product. According to the method of the present invention, the existing equipment used in the conventional particle board manufacturing process using formaldehyde condensation resin can be put to practical use without any modification.

The method of the present invention is extremely significant in that it allows factory production of particle boards using polyincyanate compounds, which was previously considered impossible, to be possible.

Next, the present invention will be explained with reference to examples, where all parts and numbers in the examples are parts by weight and percent by weight.

Reference example 1 TDI ''''/2o (Mitsui Nisso Urethane Co., Ltd.'s 2,
A mixture of 4-tolylene diisocyanate and 2.6-tolylene diisocyanate in a weight ratio of 80/2o (NOO
% = 47.7%) and 100 parts of DIOL-1000 (Mitsui Nisso Urethane hydroxyl-terminated polyether polyol, average molecular weight = 1000, OH value = 112)
The SO portion was charged into a reactor and reacted at 90°C for 2 hours with stirring. The reaction product obtained was NC10%=342
This is hereinafter abbreviated as U-1.

Reference Example 2 100 parts of MDI-oR-100 (Mitsui Nisso Retan's Polymeric MDI, NCo%=60B) and 6 parts of trimethylolpropane were charged into a reactor and heated at 90°C for 2 hours.
The reaction was allowed to take place while stirring for hours. The reaction product obtained is N
CO%=245%, hereinafter abbreviated as U-2.

Reference Example 6 M:oney aR-soo (Mitsui Nisso Urethane ■ Polymeric MDI, N00%-3DJ3%) 100 parts and compound A represented by the following molecular formula H3 Compound A c2H5o-+ca2aH2o-)-□6(
an, -ca-o) and 3 parts of a were charged into a reactor and heated to 70°C.
The mixture was reacted with stirring for 6 hours. The obtained reaction product was N00% = 285%, hereinafter abbreviated as U-3.

Examples 1 to 12 As polyisocyanate compounds, reaction products U-1, U-2, U-3 and MDI-C described in Reference Examples 1 to 3 were used.
R-200 (Mitsui Nisso Urethane's polymeric ready-to-work, N
4 types of wax: Cellosol 524 (Chukyo Yushi Co., Ltd., Carnauba wax emulsion solid content = 60%), Cellosol 967 (CO% = 31.1%),
Microwax emulsion manufactured by Chukyo Yushi Co., Ltd. Solid content =
50qb), Cellosol 531 (Chukyo Yushi Co., Ltd., beeswax emulsion solid content = 30%), Polylon 69
6 (Polyethylene wax emulsion manufactured by Chukyo Yushi Co., Ltd.)
A combination of 4 types (solid content = 60 g) and water in various proportions was applied to a real press and a patch plate.

The above polyisocyanate compound, the above wax, water and urea formaldehyde resin U-7 for wood chips
55 (manufactured by Mitsui Toatsu Chemical Co., Ltd. 1.Resin content = 65%) was applied in various proportions, target board thickness: 15 Dragon, chip moisture content: 4%, target density: 0.79'/cdl, matte moisture content: 12 Resin spraying rate: 8 Heat and pressure conditions: 160℃, 4m1n, soKg/cr
Particle board was manufactured under the following conditions. The results are shown in Table-1.

(Note: The X mark in this column indicates that the CA) (b) and (C) were applied to a hot press and a patch plate, and then heat-treated at 160°C for 15 minutes.

(Note 2) In the mold releasability judgment, an O mark indicates that no adhesion occurs at all when the pressure is released, and a Δ mark indicates that there is a slight adhesion to the hot press or backing plate when the pressure is released, but it does not interfere with work. shows. The 10th press indicates the evaluation result when the press operation was repeated 10 times after 1.1 application.

(Note 3) Evaluation of board physical properties was in accordance with J Engineering SA A390B.

Comparative Example 1 MDI-〇! was used as a wood chip binder using an untreated hot press and a patch plate. Particle board was manufactured using R-200 under the same conditions as in the example, but when decompressing,
It was not possible to measure the physical properties of the board because the board surface was severely damaged due to severe adhesion to the hot press and backing plate.

Comparative Example 2 Cellosol 524, which is an emulsion of carnauba wax, was applied to a hot press and a patch plate at a ratio of 1:10, and a particle board was produced under the same conditions as Comparative Example 1, but when the pressure was released, the hot press and It was not possible to measure the physical properties of the board because the adhesion to the backing plate was so severe that the board surface was severely damaged.

Comparative Example 6 Particle board was produced under the same conditions as in Example using an untreated hot press and a caul plate and the adhesive formulation of Example 10 as a binder, but the hot press and caul plate were not affected during decompression. The adhesion was so strong that part of the board surface was destroyed.

Reference Example 4 100 parts of the product U-5 of Reference Example 6 was charged into a reactor,
A mixture of 10 parts of carnauba wax and 16 parts of n-octyl oleate was charged and stirred for 2 hours at 90-95 DEG C. and then cooled. The obtained product will be abbreviated as U-4 below.

Example 12 100 parts of the product U-4 of Reference Example 4 was dispersed in 100 parts of water using a stirrer. This U-4 aqueous dispersion was applied to a hot press and a patch plate at a ratio of 15 parts, and heated to 160°C for 20 parts.
Heat treated for 1 minute.

The above U-4 aqueous dispersion was sprayed onto wood chips with a chip moisture content of 4% so that the resin spraying rate was 8 cm.Target thickness: 15 r1/m Target density: 0.7 rd Matte water content: 12% Heat Pressure conditions: 160℃, 4 min, 50Kq/cr
Particleboard was manufactured under the following conditions, but adhesion to the hot press and caulking plate did not become a problem at all even after 200 times of board making.

Comparative Example 4 Particle board was produced under the same conditions as in Example 12, without hot pressing and treatment on the caul plate, but the particles adhered to the hot press and the caul plate, which caused a major hindrance to the work. Ta.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (2)

[Claims] (1) When producing particle board by press-molding chips coated with a polyisocyanate compound, hot press and press the board with a) a polyisocyanate compound, Φ) a wax having a melting point of 60'C or higher. and (C) a method for producing particle board, characterized by applying water. (2) The method according to claim 1, wherein a wax having a melting point of 60° C. or higher is applied to the chip.