JPS587463B2 - Continuous manufacturing method for decorative laminates - Google Patents

Description

Detailed Description of the Invention The present invention relates to the production of decorative laminates that continuously obtain decorative laminates with good appearance and physical performance using a condensation resin of formaldehyde and a compound having an amino group on the triazine ring, which is a thermosetting resin. The method relates to a condensation resin liquid in which 10 to 80% by weight of formaldehyde is etherified in a condensate of 1 mole of a compound having an amino group on a triazine ring and 1.2 to 4.0 moles of formaldehyde. Dry a long impregnated sheet impregnated or coated with by a conventional method, and then leave it as a single layer or continuously laminate it with an impregnated or unimpregnated sheet material and use a continuous press machine to produce a material with good appearance and physical performance. There is also something about how to get a decorative board.

Conventionally, a condensation resin decorative board made of a compound having an amine group on the triazine ring and formaldehyde requires a large-scale flat press apparatus using a hot-coult method, which is a batch method.

Therefore, the products obtained by this method have low productivity and high cost, and since a large amount of condensed water is discharged during the curing process of the melamine-formaldehyde resin, long decorative boards with no length limit are continuously produced. It was nearly impossible to obtain.

On the other hand, there is a method of continuously obtaining a long decorative board by using unsaturated polyester resin, diallyl phthalate resin, etc., which do not discharge condensed water during the curing process.

However, if we compare the physical properties of decorative laminates made from unsaturated polyester resins, diallyl phthalate resins, etc. and decorative laminates made from a condensation resin of formaltehyde and a compound having an amine group in triazide 4, we find that the flexibility of the decorative laminate is The former is superior, but the latter is clearly superior in terms of physical performance such as hardness, heat resistance, and boiling resistance.

Therefore, the present invention provides a highly efficient, inexpensive decorative board with no length limit, manufactured using a continuous press machine using a condensation resin of formaldehyde and a compound having an amine group on the triazine ring, which has good physical performance. This is what I am trying to do.

The condensation resin liquid used in the present invention contains 1 mole of a compound having an amine group on the triazine ring, such as melamine, acetoguanamine, or penzoguanamine, and 1 mole of formaldehyde.
2 to 4.0 mol of formaldehyde and 10
~80% by weight of one or more of monohydric alcohols such as methanol, butanol, and propanol, or polyhydric alcohols such as dihydric alcohols such as polyethylene glycol and polypropylene glycol, and trihydric alcohols such as glycerin. It is etherified with alcohol.

As for the polyhydric alcohol, polyhydric alcohols in which at least one of the hydroxyl groups has been etherified with methanol, ethanol, etc. can also be used.

However, if the etherification is less than 10% by weight, a large amount of condensed water will come out during the heat curing process, and the crosslinking density of triazine rings will increase, resulting in poor bending workability of the decorative board obtained. There is a drawback.

On the other hand, if the etherification exceeds 80% by weight, the number of bonded side chains decreases, which is undesirable because the physical properties such as heat resistance and bending strength of the resulting decorative board deteriorate.

Here, the reason for etherification using various alcohols as described above will be explained.

First, condensation resins of formaldehyde and compounds that have an amino group on the triazine ring generally have methylol groups, and during thermal condensation, a large amount of condensation occurs due to the condensation reaction between methylol groups or between methylol groups and amine groups. Water is produced.

However, in the conventional method of manufacturing decorative laminates using a large-scale flat plate press using the hot gold method,
Even though a large amount of condensed water was generated as described above, defects such as gas unevenness did not occur on the surface of the decorative board because of the cooling process under pressure.

On the other hand, a so-called continuous press device, which is used to manufacture a decorative laminate by continuously heating and pressing it as in the present invention, only heats and presses the decorative laminate and does not have a cooling step unlike the conventional method.

Therefore, when there is a large amount of condensed water produced during the condensation reaction, gas unevenness occurs on the surface of the decorative laminate, making it impossible to continuously obtain a long decorative laminate.

However, since the methylol group is etherified using various alcohols as in the present invention, no condensation water is produced in the condensation reaction, so a long decorative board is concatenated using a new continuous press equipment on an industrial scale. and can be obtained quickly.

Next, the reason for using various alcohols for etherification will be explained.

(1) Among various alcohols, decorative boards using condensed resins in which methylol groups are etherified with polyhydric alcohols have the advantages of excellent flexibility, surface hardness, and heat resistance.

(2) In the case of a condensation resin in which the methylol group is etherified using a part of the hydroxyl group of the polyhydric alcohol previously etherified with a monohydric alcohol,
Since the amount of hydroxyl groups contained in the condensed resin is significantly reduced, the water resistance of the decorative board is significantly improved, and a decorative board with excellent flexibility, surface hardness, and heat resistance can be obtained.

As for the etherification method, for example, when melamine is used as a compound having an amine group on the triazine ring, 1 mole of melamine is mixed with 1 aqueous formaldehyde solution.
．． Add 2 to 4.0 mol of melamine, adjust the pH to 8.0 to 10, stir at 85 to 95°C, and stop heating and stirring when the melamine is completely dissolved in the formaldehyde aqueous solution.

Conventional reaction times are approximately 15 to 60 minutes.

Then, the dissolved resin liquid is cooled, methylolmelamine is isolated, water contained in it is removed, and alcohol such as methanol or butanol is added to pH 5.5-6.3.
After making the mixture acidic, the mixture is heated and stirred at 75 to 80°C.

Then, the total amount of methylated methylol groups, methylol groups, and free formaldehyde was determined by the acid-treated iodine method, and the amount of methylated methylol groups was determined by subtracting the total amount by the iodine method from the total amount of the acid-treated iodine method. Confirm that 80% by weight is etherified.

Another etherification method is to add 8 to 1 mol of formaldehyde to 1 mol of melamine and 1.2 to 4.0 mol of formaldehyde aqueous solution.
Add 3 moles of butanol or other higher alcohol, and then add 0.25 to 1 mole of hydrochloric acid to adjust the pH.
Adjusted to 4.5 to 6.0 and heated to 30 to 6 at 40 to 70°C.
Allow the reaction to run for 0 minutes.

The Miyauchi colorimetric method can be used to confirm that etherification is 10 to 80% by weight.

After the reaction is complete, sodium carbonate is added to neutralize the acid, then the aqueous layer is removed, and the butyl alcohol or other higher alcohol layer is distilled to completely remove water.

Another etherification method is to add 1.2 to 4.0 moles of a methanol solution (46% solids) containing about 46% formaldehyde to 1 mole of melamine.
．． The reaction temperature is adjusted to 5 to 6.0 and the reaction is carried out at 75 to 85°C for 1 to 2 hours.

Furthermore, as another etherification method, 1.2 to 4.0 moles of formaldehyde are added to 1 mole of melamine, the pH is adjusted to 8.0 to 10.0, and the mixture is heated at 85 to 95°C for 30 to 60 minutes. Perform the reaction.

After that, after adjusting the pH to 10-12, ethylene glycol or other polyhydric alcohol is added,
There is also a method in which the reaction is carried out at 70 to 90°C for 60 to 120 minutes.

Note that the above-mentioned acid treatment iodine method and iodine method can be used to confirm that 10% by weight or more is etherified.

In principle, there are four types of etherification methods as described above, including compounds with an amino group on the triazine ring, molar modification of compounds with an amino group on the triazine ring and formaldehyde, and alcohols used for etherification. It goes without saying that the reaction temperature and time will vary depending on the pH, etc.

As described above, a curing agent, a mold release agent, etc. are added to the etherified triazine ring containing an amine group and a formaldehyde condensation resin liquid to impregnate objects such as overlay paper, patterned paper, kraft paper, asbestos paper, cloth, etc. A compound having an amine group on the triazine ring is impregnated or coated by a conventional method, and the impregnated or coated product is applied in a single layer or laminated, or the impregnated object such as kraft paper or cloth for decorative laminates is impregnated with a compound having an amine group on the triazine ring. and formaldehyde condensation resin and a resin liquid having good compatibility, such as melamine resin, alkyd resin, etc., or by laminating impregnated materials impregnated with one or more liquids such as melamine resin, alkyd resin, or aluminum plate, aluminum foil, iron plate, fiber. It is laminated with materials that cannot be impregnated, such as boards, plywood, particle boards, and resin boards, and then heated and pressed using a continuous press machine to form the product.

In this case, the impregnation rate of the resin and the impregnation drying conditions vary, but preferably the impregnation rate is 70 to 180% (with respect to the object to be impregnated) at a drying temperature of 70 to 140°C and a drying time of 2 to 15%.

The continuous press device in this case is one that can continuously manufacture the product without any breaks, such as a rotary press device consisting of a rotating cylinder (drum) and an endless steel belt, such as a double belt press or an endless steel belt press. A continuous press device that presses a steel belt from above with a caterpillar or rolls, or a continuous press device such as a large number of roll presses connected in series, is used to continuously heat and pressurize the steel belt.

In addition, in order to obtain a decorative board with a desired gloss and flat surface using the above-mentioned continuous press device, the surfaces of the steel belt and roll must have the desired gloss and flat surface. .

Furthermore, various types of gloss can be imparted to the surface of the decorative board by interposing a flat, thin sheet-like material such as aluminum foil with various types of gloss between the steel belt and the decorative board.

On the other hand, in obtaining a decorative board with an embossed pattern,
(a) A desired embossed pattern is given to the surface of the steel belt or roll in advance, or (b) The surface of the steel belt or roll is flat, and a long sheet with an embossed pattern between them. It is also possible to provide an arbitrary embossed pattern on the surface of the decorative board by interposing a material.

As described above, the method for continuously manufacturing a decorative laminate of the present invention involves continuously heating and pressurizing a long laminated sheet material constituting a decorative laminate using various continuous molding press devices, The molding conditions vary depending on the degree of etherification of formaldehyde, the type of alcohol used, the type and amount of the curing agent, etc.

As described above, the molding conditions vary, but most preferably the temperature is 100 to 170°C, the pressure is 2 to 20 kg/cm2, and the molding time is 30 to 60 seconds.

As a reference, an impregnated sheet-like material made of one of the triazine derivative resins, with an upper layer of almelamine resin and a lower layer of phenol resin, was prepared using a typical melamine resin decorative board made by conventional hot/cold press molding. , a continuously molded decorative board (B) using diallyl phthalate resin, and 1
The table below shows a comparison of physical properties with a continuously molded decorative board (C) using a condensate of formaldehyde and a compound having an amino group on the triazine ring that has been etherified in an amount of 0 to 80% by weight.

The base materials are all laminates of patterned paper and kraft paper.

(1) The physical performance test in the above table was based on JIS-K6902.

Comparing the physical performance of (A), a conventional high-pressure press molded decorative board using melamine resin, with (B), a continuously molded decorative board using diallyl phthalate resin, it has poor bending workability, but has other properties such as heat resistance and hardness. It's much better in that respect.

Continuously molded decorative laminate with 10 to 80% by weight etherification of (C) is compared to decorative laminate of diallyl phthalate resin of (B).
It can be seen that although the bending workability is slightly inferior, in other respects it has physical properties similar to the high-pressure molded decorative board of (A).

(2) The numbers in the production column indicate the productivity of the continuous molded product relative to the productivity of the high-pressure molded decorative laminate in (A), which is set at 100.

The productivity index in the above table is based on the fact that the curing mechanism of the resin varies depending on the resin composition or the type of curing agent, etc., as described above.
Therefore, there will be various changes, but by combining these conditions, even if it is bad, an improvement of 25% is possible.

Next, embodiments of the present invention will be described.

Example 1 A slurry prepared by mixing 1 mole (126 g) of melamine with 3.5 moles (228 g) of formaldehyde methanol solution and adjusting the pH to 6.0 with 1.0% sodium carbonate was heated to 75% in a reaction vessel equipped with a reflux condenser. The reaction mixture was heated and stirred at ~80°C, and after about 1 hour, when it became cloudy in water, it was cooled to obtain a resin liquid used in the present invention.

Add 0.5% of acidic catalyst and 0.5% of mold release agent to this resin.
% and impregnated it into patterned paper for decorative laminates with a basis weight of 120 g/m2, and dried at about 100°C for 5 minutes, so that the impregnation rate was 140% (1.4 times the weight of the paper). A continuous impregnated paper was obtained.

In addition, kraft paper with a basis weight of 190 g/m2 was similarly impregnated.
An impregnated paper with an impregnation rate of 100% was obtained by drying at 00°C for 5 minutes.

These patterned papers and kraft paper impregnated paper were continuously laminated and passed between a rotating drum with a diameter of 1.5 m and an endless metal belt that revolved around its outer periphery, at a temperature of 150°C and a pressure of 4 kg.
/cm2 at a speed of 4 m/min, a decorative board with a beautiful glossy surface was obtained.

The physical performance fully satisfied the value (C) in the table above.

Example 2 1 mole (126 g) of melamine and 2 formaldehyde solutions
mol (162g) and P with 10% caustic soda.
The slurry adjusted to H9 was reacted by heating and stirring at 85 to 95°C in a reaction vessel equipped with a reflux condenser, and after about 30 minutes, 1
After adjusting the pH to 12 by adding 0% caustic soda, 0.5 mol (g) of polyethylene glycol was added and stirred at 70 to 90°C for 100 minutes.

Thereafter, it was cooled to obtain a resin liquid used in the present invention.

To this resin liquid, 0.5% of a latent curing agent and 0.5% of a mold release agent were added, and an overlay paper with a basis weight of 25 g/m2,
Patterned paper with a basis weight of 80g/m2 and a basis weight of 150g/m2
The impregnation rates for each base paper of the kraft paper in No. 2 are 250% for overlay paper, 100% for patterned paper, and 8% for kraft paper.
A long continuous paper impregnated with 0% was obtained.

These impregnated papers were laminated continuously and inserted between the endless metal belts running along the outer periphery between the upper and lower rotating drums with a diameter of 2 m, at a temperature of 160°C and a pressure of 15 kg/c.
When heated and pressurized at a speed of 8 m/min, a decorative board with a beautiful glossy surface was obtained.

The physical performance fully satisfied the value (C) in the table above.

Claims (1)

[Claims] 1 A reaction product of 1 mole of a compound having an amino group on the triazine ring and 1.2 to 4.0 moles of formaldehyde, in which 10 to 80% by weight of the formaldehyde is etherified, is usually used. 1. A method for continuously manufacturing decorative laminates, which comprises continuously laminating long impregnated sheets impregnated and dried by the method described above, and bonding the laminate under heat using a continuous press device.