JPH0952972A - Reclamation of amino resin waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reclaim amino resin waste product as a raw material for molded products whose strength and fragility are improved without disposition in vain such as by calcination or land reclamation. SOLUTION: This reclamation can be carried out by adding granules of amino resin thermally cured products to formalin at 30-100 deg.C before the reaction of an amino compound with formaldehyde followed by agitating (process D), by adding granules of the amino resin thermally cured products on the reaction of an amino compound with formaldehyde (process A), or by adding a curing agent and granules of the amino resin thermally cured products after the reaction of an amino compound with formaldehyde (process B), in other words, by adding granules of the amino resin thermally cured products to the reaction system where the initial condensate of the amino resin is obtained. Thus, the molded product obtained from the initial-stage condensate containing the amino resin thermally cured product has a practically enough strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a method of reusing amino resin waste such as defective products and burrs produced when a kitchen appliance, daily sundries, lacquer ware, tableware, and decorative articles are heat-molded with amino resin.

[0002]

2. Description of the Related Art The inventors of the present invention observed defective products such as urea resin and melamine resin produced in a heat molding process and amino resin wastes such as burrs by Raman spectroscopy and found that they were once thermoset. It has been confirmed that the methylol group remains in these amino resin wastes. Since the presence of the methylol group suggests the possibility of a three-dimensional cross-linking reaction,
An attempt has been made to reuse by mixing with a raw amino resin molding material which has not been subjected to thermosetting treatment such as molding and heat molding.

However, the molded product obtained by mixing wastes is not practical because it is inferior in strength and brittleness to the molded product obtained only by using the raw amino resin molding material. For this reason, the amino resin wastes have been collected by local governments and private processing companies and disposed of by incineration or landfill.

[0004]

However, in the case of incineration, NO generated from amino resin waste during combustion.
There are still some problems such as measures against harmful gases such as x, severe damage to the incinerator, securing a large storage site, etc. Is expected to become a serious social problem.

The present invention has been made in view of the above problems, and an object of the present invention is to incinerate or reclaim even amino resin waste thermoset by molding or the like. An object of the present invention is to provide a method for reusing an amino resin waste that can be used as a raw material for a molded product with improved strength and brittleness without wasteful disposal by treatment.

[0006]

In order to achieve the above object, the method for recycling amino resin waste according to the present invention is a method of reacting an amino compound with formaldehyde and then adding a curing agent to carry out the initial condensation of the amino resin. The reaction system for obtaining a product is constituted by adding powders of amino resin thermosetting product, which is to be a waste, to an amino resin recycled molded product having practical strength by the method of the present invention. I was able to get it.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The reaction system for obtaining the precondensate of the amino resin of the present invention may be a conventional method. That is, the amino compound and formaldehyde are added in an alkaline range of pH 7 to 12, 30 to
The liquid is subjected to an addition reaction at 100 ° C. to obtain a liquid initial adduct, and then a curing agent is added to the initial adduct to obtain a solid initial condensate in which the condensation reaction is slightly advanced. When this initial condensate powder is heat-molded, a stronger three-dimensional network structure is formed between the molecules, resulting in a hard molded product.

As the amino compound of the present invention, urea, melamine, guanamines and the like can be used. Examples of amino resins obtained from these, formaldehyde and a curing agent include urea resin, melamine resin and guanamine resin. To be The addition ratio of the amino compound and formaldehyde is preferably 1 to 3 mol of formaldehyde relative to 1 mol of the amino compound. As the curing agent of the present invention, ammonium chloride, acid anhydrides such as phthalic anhydride and salts thereof, oxalic acid dimethyl ester, salicylic acid urea adduct and the like are used.
0.01 with respect to 0 part by weight (hereinafter simply referred to as "part")
˜3 parts are preferably added. Furthermore, if necessary, a compounding agent such as a release agent, a colorant, a filler, a reinforcing agent is added.

Examples of the amino resin thermosetting product as the waste of the present invention include electric appliances, kitchen appliances, daily necessities,
It is possible to use a heat-molded product of an amino resin used in lacquer ware, tableware, decorative articles, and the like, defective products and burrs produced in the process of heat-molding these amino resins. This amino resin thermoset is 1 per 100 parts of amino compound.
It is desirable to add ~ 300 parts. In addition, it is preferable that the thermosetting resin of amino resin is a powder or granular material in consideration of reactivity with formaldehyde and handleability. The particle size of the powder or granular material may be such that the methylolation reaction can be sufficiently carried out by contact with formaldehyde, and the size can be easily handled, for example, 45 μm or more and 1000 or more.
It is preferably about μm or less.

The timing at which the thermosetting resin for amino resin is added to the reaction system for obtaining the precondensation product for amino resin may be such that the thermosetting resin for amino resin can react with formaldehyde or a condensation reaction that causes three-dimensional crosslinking. If it is a condition, it will not be specifically limited.

For example, as shown in FIG. 1B, prior to the reaction of the amino compound with formaldehyde, the powder of the thermosetting amino resin is added to formalin at 30 to 100 ° C. and stirred. (Hereinafter, referred to as D method), or as shown in FIG. 1 (a), when the amino compound is reacted with formaldehyde in the alkaline region, a powder or granular material of the amino resin thermosetting product is added (hereinafter, referred to as A). Method), or after the reaction of the amino compound with formaldehyde, a hardener and powder of the amino resin thermosetting product can be added (hereinafter referred to as method B). By the way, the conventional method is a method in which the powder of the amino resin initial condensation product is directly mixed with the powder of the amino resin thermosetting product to form a molding material (hereinafter, referred to as method C).

Thus, the initial condensate containing the thermosetting amino resin is obtained. Therefore, the initial condensate is crushed into a powder or granular material, and a compounding agent is further added to prepare a molding material. When this is heated and pressed by compression molding, extrusion molding, transfer molding, injection molding, etc., a molded product containing the thermosetting amino resin product is obtained. The conditions of heat and pressure molding vary depending on the molding method and are not particularly limited, but a mold temperature at which the initial condensate of the amino resin can be thermoset is preferably 130 to 180 ° C., and the molding pressure is 100. It is good to be 400 kgf / cm ² .

[0013]

EXAMPLES Comparative Example U, Examples 1 to 12, and Comparative Examples 1 to 4 are related to "urea resin". Then, in Examples 1 to 3 and Comparative Example 1, molded products obtained by heat compression molding (thermosetting) the initial condensate of the urea resin obtained by the addition condensation reaction system of urea and formaldehyde in Comparative Example U, Further, the powder was pulverized into a granular material, which was regarded as a thermosetting cured product of urea resin as a waste (hereinafter, the thermosetting cured product as a waste is referred to as a waste resin) and used.

Comparative Example U. 1.5 mol of formaldehyde (tested with 37% formalin; the same applies below) was added to 1 mol of urea, and the pH was 7.5 to 8.5 at 50 ° C. for 1 hour.
Ammonium chloride as a curing agent was added to the initial addition product of the urea resin obtained by the reaction in step (1) and further dried under reduced pressure to obtain a solid initial condensation product of the urea resin. This has a particle size of about 300 μm
It was pulverized into a urea resin molding material. This material is a raw molding material with no history of thermosetting. Next, the urea resin molding material is molded with a compression molding machine at a molding pressure of 150 kg / c.
A molded product (hereinafter, a resin which is heat-molded from a raw molding material is referred to as a virgin resin) was obtained by heat-molding at m ² at 160 ° C. for 2 minutes. The size and shape of the molded product is JIS-K-69
It complies with 11.

Example 1 (method A). A granular material having a particle size of about 300 μm obtained by crushing the urea resin molded product of Comparative Example U was used as a waste resin. Waste resin 30 for 100 parts of urea
After adding 1.5 parts of formaldehyde to 1 mol of urea, a reaction system similar to Comparative Example U was used.
A molded product containing the waste resin was obtained.

Example 2 (method B). Formaldehyde (1.5 mol) is added to urea (1 mol), and the pH is adjusted to 50 ° C for 1 hour.
Ammonium chloride as a curing agent was added to the initial addition product of the urea resin obtained by reacting at 7.5 to 8.5, and urea 1 was further added.
After adding 30 parts of the waste resin to 00 parts, in the same reaction system as in Comparative Example U, a molded product containing the waste resin was obtained.

Example 3 (method D). 37 to 30 parts of waste resin
% Formalin (75 parts) was added, and the mixture was reacted at 50 ° C. for 1 hour. Next, after adding 100 parts of urea, a molded product containing a waste resin was obtained in the same reaction system as in Comparative Example U.

Comparative Example 1 (method C). To the urea resin molding material obtained in Comparative Example U, 30 parts of waste resin was added as it was and mixed sufficiently, and this was molded under a molding pressure of 15 using a compression molding machine.
A molded product was obtained by pressurizing at 0 kg / cm ² and 160 ° C. for 2 minutes. That is, in the method C, the powder particles of the waste resin are simply blended with the powder particles of the initial condensate obtained in the reaction system of the amino resin, and this is used as the molding material.

In Examples 4 to 6 and Comparative Example 2 below, burrs produced when industrially producing buttons by heat compression molding a mixed material prepared by mixing a urea resin with a pigment, a filler, etc. The defective product was crushed and then used as a waste resin.

Example 4. A molded product containing waste resin was obtained in the same reaction system as in Example 1 (method A), except that defective products, burrs, and the like generated in the button molding process were crushed and used as waste resin.

Embodiment 5 FIG. A molded product containing the waste resin was obtained in the same reaction system as in Example 2 (method B), except that defective products, burrs, and the like generated in the button molding process were crushed and used as the waste resin.

Embodiment 6 FIG. A molded product containing waste resin was obtained in the same reaction system as in Example 3 (method D), except that defective products, burrs, and the like generated in the button molding process were crushed and used as waste resin.

Comparative Example 2 A molded product containing the waste resin was obtained in the same manner as in Comparative Example 1 (method C), except that defective products, burrs, and the like generated in the molding process of the button were crushed and used as the waste resin.

In Examples 7 to 9 and Comparative Example 3 below, burrs and defects that were produced during the industrial production of imitation pearls by compression molding a mixed material prepared by mixing white pulp with urea resin The good product was crushed and then used as a waste resin.

Example 7. A molded product containing the waste resin was obtained in the same reaction system as in Example 1 (method A), except that defective products, burrs, and the like generated in the process of molding the pearl were crushed and used as the waste resin.

Example 8. A molded product containing the waste resin was obtained in the same reaction system as in Example 2 (method B), except that defective products, burrs and the like generated in the process of molding the pearl were crushed and used as the waste resin.

Example 9. A molded product containing the waste resin was obtained in the same reaction system as in Example 3 (method D), except that defective products, burrs and the like generated in the process of molding the pearl were crushed and used as the waste resin.

Comparative Example 3 A molded product containing a waste resin was obtained in the same manner as in Comparative Example 1 (method C), except that defective products, burrs, and the like generated in the process of molding a pearl were crushed and used as the waste resin.

In Examples 10 to 12 and Comparative Example 4 below, a mixed material prepared by mixing a urea resin with a black pigment, newspaper, etc. was heated and compression molded to obtain a lacquerware base (here,
Burrs and defective products produced during the industrial production of trays were crushed and then used as waste resin.

Example 10. A molded product containing the waste resin was obtained in the same reaction system as in Example 1 (method A), except that defective products, burrs, and the like produced in the tray molding process were crushed and used as the waste resin.

Embodiment 11 FIG. A molded product containing waste resin was obtained in the same reaction system as in Example 2 (method B), except that defective products, burrs, and the like generated in the tray molding process were crushed and used as waste resin.

Example 12 A molded product containing the waste resin was obtained in the same reaction system as in Example 3 (method D), except that defective products, burrs and the like generated in the tray molding process were crushed and used as the waste resin.

Comparative Example 4 A molded product containing a waste resin was obtained in the same manner as in Comparative Example 1 (method C), except that defective products, burrs and the like generated in the tray molding process were crushed and used as the waste resin.

On the other hand, the following Comparative Example M, Example 13, Example 14, and Comparative Example 5 relate to "melamine resin". Then, in Examples 13, 14 and Comparative Example 5, molding obtained by heat compression molding (thermosetting treatment) of the initial condensate of the melamine resin obtained by the addition condensation reaction system of melamine and formaldehyde in Comparative Example M. The product was crushed and used as a waste resin.

Comparative Example M. 2.2 mol of formaldehyde was added to 1 mol of melamine, and the pH was adjusted to 7. at 80 ° C. for 1 hour.
Ammonium chloride as a curing agent was added to the initial addition product of the melamine resin obtained by the reaction at 5-8.5, and further dried under reduced pressure to obtain an initial condensation product of the solid melamine resin. This was crushed to a particle size of about 300 μm to obtain a melamine resin molding material. Next, the melamine resin molding material was heat-molded using a compression molding machine at a molding pressure of 150 kg / cm ² and 160 ° C. for 2 minutes to obtain a molded product (virgin resin (size and shape: J
IS-K-6911))) was obtained.

Example 13 (method A). The granular material having a particle size of about 300 μm obtained by pulverizing the melamine resin molded product of Comparative Example M was used as a waste resin. After adding 30 parts of the waste resin to 100 parts of melamine and further adding 2.2 mol of formaldehyde to 1 mol of melamine, a molded product containing the waste resin was obtained in the same reaction system as in Comparative Example M.

Example 14 (method D). About 52 parts of formaldehyde was added to 30 parts of the waste resin and reacted at 50 ° C. for 1 hour. Then, after adding 100 parts of melamine, Comparative Example M
A molded product containing a waste resin was obtained in the same reaction system as described above.

Comparative Example 5 (method C). 30 parts of waste resin was added to the melamine resin molding material obtained in Comparative Example M, and this was molded using a compression molding machine at a molding pressure of 150 kg / cm ² , 1
A molded product was obtained by pressing at 60 ° C. for 2 minutes.

The performance of the molded products obtained in each of the examples and comparative examples described above was evaluated by the JIS-K-6911 compliant method, and the results shown in Table 1 below were obtained.

[0040]

[Table 1]

For reference, each data of Comparative Example U, Example 1 to Example 3, and Comparative Example 1 using a virgin resin of urea resin is shown in graphs in FIGS. 2 to 5.

As is clear from Table 1 and the figures, the molded products obtained by the respective examples (method A, method B, method D) are compared with the corresponding comparative examples (method C (conventional method)). Despite the low flexural modulus, the flexure is large and the flexural strength is high. That is, it can be seen that the molded product has improved strength and brittleness. Therefore, it was possible to obtain an amino resin molded product that was sufficiently practical.

The addition ratio of the waste resin to 100 parts of the amino compound was 3 in each of the above Examples and Comparative Examples.
Although the case of 0 part was shown, when the addition ratio was increased to 40 parts, for example, the flexural modulus tended to be high while the amount of deflection was low throughout the entire methods A to D. Therefore, the bending strength was almost the same as in the case of 30 parts.

The appearance of the molded articles obtained in each of the examples and the comparative examples was visually observed. According to it, in the molded product according to the conventional method, the peripheral portion became whitish and looked as a whole non-uniform. Such a phenomenon was not observed in the molded product of the virgin resin alone or the molded product of the method of the present invention, and all exhibited a uniform texture.

Further, the structure of the amino resin molded product was observed with an electron microscope (measurement magnification = 2000 times). According to this, in the cross section of the molded product molded only with the virgin resin, there were many ordered layered structures, and almost no granular structure was found. On the other hand, in the cross section of the conventional waste mixture molded product by the C method, many granular structures were scattered. In the waste-mixed molded product according to the present invention, a layered structure was observed more, though not as much as the virgin resin alone, and the granular structure was smaller than that in the conventional method. That is, it can be seen that the amino resin waste is successfully incorporated into the three-dimensional structure of the layered structure.

[0046]

INDUSTRIAL APPLICABILITY According to the present invention, it is produced by adding a thermosetting resin of an amino resin, which has been previously reacted with formaldehyde to enhance the methylol activity, during the addition reaction between the amino compound and formaldehyde, or by adding a curing agent. Since the amino resin thermosetting product was added during the condensation reaction,
It is possible to obtain an initial condensate in which the thermosetting amino resin is incorporated into the three-dimensional crosslinked structure with good affinity. Therefore, the molded product obtained by using this initial condensate as a raw material could improve the strength and brittleness to a practical level, despite containing the thermosetting amino resin. That is, the present invention can effectively reuse the amino resin thermosetting product that is a waste, and at the same time, can contribute as a measure for industrial waste measures.

[Brief description of drawings]

FIG. 1 shows a schematic step of the method of the present invention,
(A) is a block diagram showing A method and B method together with a conventional method (C method), and (b) is a block diagram showing D method.

FIG. 2 shows a virgin resin molding and A for urea resin.
6 is a graph showing the relationship between the stress and the amount of deflection of each molded product obtained by the D method.

FIG. 3 shows a virgin resin molding and A for urea resin.
6 is a graph showing the bending strength of each molded product obtained by Method D. FIG.

FIG. 4 shows a virgin resin molding and A for urea resin.
6 is a graph showing the flexural modulus of each molded product obtained by Method D. FIG.

FIG. 5: Virgin resin molding and A for urea resin
6 is a graph showing the amount of deflection of each molded product obtained by Method D. FIG.

Claims (1)

[Claims] 1. A powdery material of a thermosetting amino resin, which is a waste, is added to a reaction system in which an amino compound is reacted with formaldehyde and then a curing agent is added to obtain an initial condensation product of an amino resin. Recycling of waste amino resin waste.