JP2008056866A - Modified melamine resin composition and melamine decorative sheet for post foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a melamine decorative sheet which can be bent-processed in a small R, especially ≤4R. <P>SOLUTION: This modified melamine resin composition is characterized by reacting a mixture comprising 1.0 mole of an amino compound containing melamine as an essential component, 1.0 to 1.5 moles of a formaldehyde compound, and 0.02 to 0.1 mole of a glycidyl ether compound in a basic atmosphere. The melamine decorative sheet for post foam is characterized by laminating resin-impregnated decorative paper obtained by impregnating decorative paper for a decorative sheet with an impregnation resin liquid containing the modified melamine resin composition as a main component to resin-impregnated core paper obtained by impregnating a core material for the decorative sheet with a thermosetting resin and then heating and pressing the laminate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition used for a decorative board, and more particularly to a modified melamine resin composition and a post-form melamine decorative board.

  Conventionally, post-form melamine decorative plates used for various purposes such as sinks and countertops and doors are characterized in that they can be bent compared to ordinary melamine decorative plates. In general, however, the melamine decorative board for post foam uses a melamine-formaldehyde resin for the decorative layer that forms the surface layer, and a thermosetting resin such as a phenol resin for the core layer. However, small R, especially 6R or less is difficult, and 4R or less is extremely difficult.

As a method for solving such a problem, there are methods of lowering the molar ratio when synthesizing the melamine-formaldehyde resin or adding a plasticizer, but in these methods, the bending radius of the post-form processing can be reduced to some extent. However, it still does not have sufficient performance, and there has been a problem that general performances such as surface hardness, water resistance, heat resistance, and contamination resistance inherent to melamine-formaldehyde resin are lowered.
JP-A-61-76364 JP 59-37108 A

  The object of the present invention is to obtain a post-form melamine decorative board that can be bent almost at a right angle, such as a small R of 6R or less, particularly 2.5 to 4R, as described above. It is.

  As a result of diligent investigations, the present inventors have found that 1.0 to 1.5 moles of formaldehyde and 1.02 to 0.02 moles of glycidyl ethers per 1.0 mole of amino compound containing melamine as an essential component. By applying a modified melamine resin composition, which is prepared by reacting each of those blended at a molar ratio in a basic atmosphere, to the decorative paper which is the surface layer of the post-form melamine decorative board, I found that the problem could be solved.

  The modified melamine resin composition of the present invention is suitable as a raw material for a decorative melamine board for post-form, and exhibits excellent bending workability.

  Hereinafter, the present invention will be described in detail.

  In order to obtain the modified melamine resin composition of the present invention, a mixture of melamine and, if necessary, an amino compound such as urea, thiourea, ethylene urea, benzoguanamine, acetoguanamine, formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, furfural, etc. Initial condensation of amino-aldehyde resin by reacting an aldehyde compound and glycidyl ether with water as a solvent under heating at 70 to 100 ° C. in a basic atmosphere, for example, pH 8 to 11, preferably pH 9.2 to 9.4 Produce things.

  When the pH during the reaction is less than the lower limit, the condensation of methylolated melamine increases and gelation is likely to occur, and when the upper limit is exceeded, the stability of the resin deteriorates. Examples of the basic catalyst for adjusting the pH to the above range include sodium hydroxide, potassium hydroxide, aqueous ammonia and sodium carbonate.

The molar ratio of the amino compound containing melamine as an essential component to the formaldehyde compound is preferably 1.0 to 1.5 mol of the formaldehyde compound with respect to 1.0 mol of the amino compound. In addition, the resin becomes incomplete when cured, and surface properties tend to be inferior, and if the upper limit is exceeded, the network bonding of the resin at the final stage becomes excessive and bending workability tends to be inferior. As the aldehyde compound, it is particularly preferable to use formaldehyde or paraformaldehyde which is inexpensive and has good reactivity with the amino compound.

  The molar ratio of the amino compound to the glycidyl ether is preferably 0.02 to 0.1 mol of glycidyl ether with respect to 1.0 mol of the amino compound. On the other hand, when the upper limit is exceeded, as shown in Comparative Example 2, the hot water resistance tends to be poor.

  Examples of glycidyl ethers include polyglycidyl ethers such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylpropane polyglycidyl ether, resorcinol diglycidyl ether, Diglycidyl ether such as neopentyl diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, p-tert -Butyl phenyl glycidyl ether Glycidyl ether, and the like. By adding these glycidyl ethers, the distance between crosslinks is increased, so that post-form processability is improved.

  Among the glycidyl ethers, polypropylene glycol diglycidyl ether represented by Chemical Formula 1 that exhibits excellent post-form processability and hot water resistance is desirable, and those having n of 2 to 11 are particularly preferable.

  Further, polyethylene glycol diglycidyl ether represented by Chemical Formula 2 is desirable for the same reason, and those having n of 2 to 13 are particularly preferable.

The number of glycidyl ether groups present in one molecule is preferably 2 to 3.

  Next, the initial condensate is adjusted to neutral to slightly basic, for example, pH 6.8 to 7.5, and then heated at 60 to 80 ° C. When the pH is less than the lower limit, the reaction proceeds too much and the bending workability tends to be inferior. When the pH exceeds the upper limit, the reaction becomes slow and the crosslinking reaction hardly proceeds. Examples of the acidic catalyst for adjusting the pH include hydrochloric acid, sulfuric acid, oxalic acid, acetic acid, toluenesulfonic acid, formic acid and the like.

  Next, a decorative paper for decorative board is impregnated with a resin solution and dried to obtain a resin-impregnated decorative paper. On the other hand, as a core layer, kraft paper is impregnated with a thermosetting resin, for example, a resin solution made of melamine or phenol resin, and dried to obtain a resin-impregnated core paper, and the resin-impregnated decorative paper and the resin-impregnated core paper are laminated and heated. By applying the pressure, the melamine decorative board for post foam of the present invention is obtained.

Modified Melamine Resin Composition 1.0 mol of formaldehyde with respect to 1.0 mol of melamine, polypropylene glycol diglycidyl ether represented by Chemical Formula 1 with n = 3 (Denacol (registered trademark) EX-920, Nagase ChemteX Corporation) 0.02 mol and a suitable amount of water were added, the pH was adjusted to 9.3 with sodium hydroxide and reacted at 95 ° C. for 1 hour, then the pH was adjusted to 7.0 with formic acid and 80 ° C. The mixture was heated for 1 hour, and water was added so that the solid content was 40% to obtain a modified melamine resin composition.
Veneer resin composition post form a melamine decorative board resin impregnated decorative paper 130 g / m ² of decorative paper impregnated rate of the resin composition shown by the number 1 for the veneer is impregnated so that 120%, dried Thus, a resin-impregnated decorative paper was obtained.

Resin-impregnated core paper 180 g / m ² of kraft paper is impregnated with a resin solution for a melamine decorative board core containing phenol resin as a main component so that the impregnation ratio shown in Formula 1 is 60%, and dried to give a resin-impregnated core I got paper.
Post-form melamine decorative board 1 resin impregnated decorative paper and 3 resin impregnated core papers are laminated, heated and pressed at a temperature of 125 ° C. for 70 minutes and a pressure of 60 kgf / cm ² , and the thickness of Example 1 is 0.8 mm. A melamine decorative board for post foam was obtained.

  The same procedure as in Example 1 was carried out except that 0.1 mol of polypropylene glycol diglycidyl ether having n of 3 represented by Chemical Formula 1 was added to 1.0 mol of melamine to obtain a melamine decorative board for post foam. It was.

  In Example 1, it implemented similarly except having made formaldehyde 1.5 mol with respect to melamine.

  The same procedure as in Example 1 was carried out except that 1.5 mol of formaldehyde was added to melamine, and 0.1 mol of polypropylene glycol diglycidyl ether represented by Chemical Formula 1 and n was 3.

  In Example 4, instead of polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether (Denacol (registered trademark) EX-821, manufactured by Nagase ChemteX Corporation) represented by Chemical Formula 2 and having n of 4 was used. It carried out similarly.

  In Example 4, it replaced with polypropylene glycol diglycidyl ether, and it implemented similarly except having used the glycerol polyglycidyl ether (Denacol (trademark) EX-313, Nagase ChemteX Corporation) with 3 functional groups.

Comparative Example 1
The same procedure as in Example 1 was carried out except that 1.3 mol of formaldehyde was added to 1.0 mol of melamine, and 0.01 mol of polypropylene glycol diglycidyl ether represented by Chemical Formula 1 and n was 3.

Comparative Example 2
The same procedure as in Example 1 was carried out except that 1.3 mol of formaldehyde was added to 1.0 mol of melamine, and 0.13 mol of polypropylene glycol diglycidyl ether represented by Chemical Formula 1 and n was 3.

Comparative Example 3
The same procedure as in Example 1 was performed except that 1.7 mol of formaldehyde was added to 1.0 mol of melamine, and 0.04 mol of polypropylene glycol diglycidyl ether represented by Chemical Formula 1 and n was 3.

Comparative Example 4
In Example 1, 0.9 mol of formaldehyde with respect to 1.0 mol of melamine, and 0.1 g of polypropylene glycol diglycidyl ether represented by the formula 1 and n = 3.
It carried out similarly except having set it as 04 mol.

  The evaluation method was as follows.

  Bending workability: A test method for bending workability is to cut a sample with a width of 150 mm parallel to the paper flow direction and heat the decorative board to 160 ° C. with a bending tool having a predetermined radius. It was confirmed by visual inspection whether cracks were generated or not, R [mm] without cracks was measured, and 2.5R was evaluated as ◎, 4R as ○, and 6R as ×.

  Hot water resistance: JIS K 6902; 1998 (Thermosetting resin high pressure decorative board test method) is carried out based on the surface of the decorative board swells, cracks, discoloration, etc. ×, no change is seen Yes.

  Boiling resistance: JIS K 6902; 1998 (Thermosetting resin high-pressure decorative board test method).

  Heat resistance: JIS K 6902; 1998 (Thermosetting resin high-pressure decorative board test method) is carried out according to JIS K 6902; It was.

  Resin stability: The melamine resin composition was stored in a thermostatic bath at 5 ° C. and 40 ° C. for 96 hours, and those having a great change in properties such as separation, cloudiness, solidification, etc. were marked with “X”, and those without were marked with “Good”.

Claims (2)

Base compound containing 1.0 to 1.5 mol of formaldehyde compound and 0.02 to 0.1 mol of glycidyl ether with respect to 1.0 mol of amino compound containing melamine as an essential component A modified melamine resin composition characterized by reacting in a neutral atmosphere. A resin-impregnated decorative paper obtained by impregnating a decorative paper for decorative board with a resin liquid for impregnation mainly comprising the modified melamine resin composition according to claim 1; and a thermosetting resin impregnated in a core material for the decorative board. A melamine decorative board for post-form, wherein the resin-impregnated core paper is laminated and heated and pressed.