JPH11106464A - Amino resin, its production and molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject resin hardly forming reactional by-products when carrying out the hot molding and processing by reacting an melamine with an aldehyde and specifying the ratio of methylene bonds and the total amount of methylol groups and alkyl ether groups. SOLUTION: (A) A melamine (e.g. benzoguanamine) is reacted with (B) an aldehyde (e.g. paraformaldehyde) in an amount of preferably 0.1-1.0 mol, preferably 0.4-0.9 mol based on 1 mol component A in a ketonic solvent (e.g. moethyl isobutyl ketone) under acidic conditions (preferably at pH4-5), preferably at 50-200 deg.C to afford the objective resin which is a precondensate containing 0.1-1.0 mol, preferably 0.2-0.8 mol methylene bonds and <=1.0 mol, preferably <=0.9 mol total amount of methylol groups and alkyl ether groups based on 1 mol structural unit containing the triazine nucleus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amino resin suitable for use as a flame retardant improver for a molded article, a production method thereof, and a molding material.

[0002]

2. Description of the Related Art In order to improve the flame retardancy of molded products,
BACKGROUND ART An amino resin containing a triazine nucleus such as a melamine resin is blended in a molding material. The melamine resin used for such purpose is an initial condensate obtained by reacting melamine and formaldehyde under alkaline conditions. Mainly etherified alkyl etherified melamine.

[0003]

However, since such a melamine resin contains a methylol group or an alkyl ether group, it can undergo self-condensation of these functional groups or a functional group of another resin during heat molding. A reaction by-product such as water, alcohol, formaldehyde, etc. is produced by the co-condensation of Therefore, the molded article is inferior in water absorption and dimensional stability.

[0004] The present invention has been made in view of such circumstances, and an amino resin having a small amount of reaction by-products during heat molding, a method for producing the same, and the formation of reaction by-products during heat molding are small. Accordingly, it is an object to provide a molding material having few voids.

[0005]

The invention according to claim 1 is an initial condensate obtained by reacting a melamine and an aldehyde, wherein the methylene derivative is used per mole of a structural unit containing a triazine nucleus. An amino resin having a bond of 0.1 to 1.0 mol and a total amount of a methylol group and an alkyl ether group of 1.0 mol or less.

When the total amount of the methylol group and the alkyl ether group exceeds 1.0 mol per 1 mol of the structural unit containing a triazine nucleus, it is not preferable because the amount of reaction by-products at the time of heat molding increases. It is more preferable that the total amount of the methylol group and the alkyl ether group is 0.9 mol or less from the viewpoint of reducing the amount of the reaction by-product during the thermoforming. If the number of methylene bonds is less than 0.1 mol per 1 mol of the structural unit containing a triazine nucleus, mononuclear melamines, that is, unreacted melamines increase, and the moldability decreases. On the other hand, if the number of methylene bonds exceeds 1.0 mol, gelation occurs during the synthesis. From this fact, the amount of the methylene bond is 0.1 to 1 mol of the structural unit containing the triazine nucleus.
More preferably, it is 2 to 0.8 mol.

As the melamines, melamine, benzoguanamine and the like can be used. Use of benzoguanamine is preferred because it hardly gels during the synthesis, and has excellent solvent solubility and compatibility with other resins. That is, the invention according to claim 2 is the amino resin according to claim 1, wherein the melamine is benzoguanamine.

The amino resin of the present invention can be produced by reacting melamines and aldehydes under acidic conditions. It is not preferable to react melamines and aldehydes under alkaline conditions, because the reaction of converting the amino group of melamine to methylol mainly proceeds. By reacting melamines and aldehydes under acidic conditions, dehydration condensation also proceeds to form a methylene bond. And aldehydes 0.1 to 1 mol of melamines
By setting the amount to 1.0 mol, the number of moles of the methylene bond can be set to an expected number. That is, the invention according to claim 3 is characterized in that aldehydes are added in an amount of 0.1 mol per mol of melamines.
3. The reaction according to claim 1, wherein the reaction is carried out under acidic conditions.
The method for producing an amino resin described in (1). At this time, the aldehyde is added in an amount of 0.4 to 1 mol per melamine.
More preferably, the ratio is 0.9 mol.

As a solvent used in the reaction, a ketone solvent is preferable because it has excellent solubility and does not generate an alkyl ether group unlike an alcohol solvent. That is, the invention according to claim 4 is the method for producing an amino resin according to claim 3, wherein melamines and aldehydes are reacted in a ketone-based solvent.

The amino resin of the present invention is blended in a molding material, and is suitably used for making a molded article flame-retardant. That is, the invention according to claim 5 is a molding material containing the amino resin according to claim 1 or 2.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The melamine used in the production of the amino resin of the present invention may be any compound having a triazine nucleus in the molecule. In addition to the above-mentioned melamine and benzoguanamine, diguanamine such as spiroguanamine is used. be able to. In addition, as the aldehyde used in the production of the amino resin of the present invention, formalin, paraformaldehyde, and the like, which are widely used in the production of a melamine resin, can be used, but are not limited thereto.

Ketones used as a solvent in the reaction include acetone, methyl ethyl ketone, methyl isobutyl ketone and the like.

In the reaction for producing the amino resin, melamines, aldehydes and ketones are mixed, heated under acidic conditions (preferably pH 4 to 5) to form methylol and condense, and then the solvent is removed. Done in a way. The heating temperature can be appropriately selected in the range of 50 to 200 ° C. Here, when the heating temperature is lower than 50 ° C., the reaction time is prolonged. On the other hand, when the heating temperature is higher than 200 ° C., the thermal decomposition of the resin is increased, and the desired amino resin tends to be hardly obtained. If the pH is less than 4, the resin is likely to gel,
If it exceeds 5, a large number of methylol groups will remain, and the desired amino resin tends to be difficult to obtain.

The amino resin of the present invention is blended into a molding material mainly for imparting flame retardancy. The molding material of the present invention contains, as essential components, a base resin such as a phenol novolak resin, an aniline-modified phenol novolak resin, a cresol novolak resin, a mixture of an epoxy resin and various phenol resins, and the amino resin. As the main agent,
Phenol novolak resins and aniline-modified phenol novolak resins are preferred because good molded articles with few voids can be easily obtained. The amount of the amino resin is from 1 to 1 based on 100 parts by weight (solid content) of the base resin.
It is preferably added in an amount of 00 parts by weight, more preferably 5 to 50 parts by weight. If the amount is less than 1 part by weight, the effect of imparting flame retardancy is not sufficient, and if it exceeds 100 parts by weight, the strength of the molded article tends to decrease.

The molding material of the present invention may contain other appropriate additives depending on the desired purpose, as long as the performance is not impaired. Examples of such additives include organic or inorganic fillers such as rock wool, glass fibers, synthetic fibers, calcium carbonate, talc, clay, silica, etc .; curing catalysts such as phthalic anhydride, p-toluene Sulfonic acid, dimethyl oxalate,
Dibenzyl oxalate, dimethyl phthalate, benzoyl peroxide, epichlorohydrin, p-toluenesulfonic acid triethanolamine salt, 2-aminoethylsulfonic acid, dimethylanilinesulfonic acid hydrochloride, melamine oxalate, ammonium chloride, ammonium phosphate, phosphoric acid Trimethyl, acetamide, oxamide and the like; inorganic or organic pigments such as titanium oxide, zinc oxide, zinc sulfide,
Bengala, navy blue, barium sulfate, iron black, ultramarine blue, carbon black, lithopone, titanium yellow, cobalt blue, Hanzai yellow, benzidine yellow, lake red, aniline black, dioxazine violet, quinacridone red, quinacridone violet,
Naphthol yellow, phthalocyanine blue, phthalocyanine green and the like; lubricants or plasticizers such as zinc stearate, zinc myristate, aluminum stearate, calcium stearate, butyl stearate, stearyl stearate, dioctyl phthalate, dibutyl phthalate, stearamide, ε-caprolactam, oleic acid amide, linoleic acid amide, stearyl alcohol, polyoxyethylene stearate, glycerin, polyethylene glycol monooleate and the like.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Hereinafter, “parts” means “parts by weight” and “%” means “% by weight”.

Synthesis of phenol resin 1.9 kg of phenol, formalin (37% aqueous solution)
1.15 kg and 4 g of oxalic acid were charged into a 5-liter flask and reacted at a reflux temperature for 6 hours. Subsequently, the internal pressure was reduced to 66.661 hPa or less to remove unreacted phenol and water, thereby obtaining a phenol resin. The obtained phenol resin had a softening point of 89 ° C. (ring and ball method).

Synthesis of aniline-modified phenolic resin 1.7 kg of the phenolic resin obtained above (corresponding to 16 mol of hydroxyl groups) was mixed with 0.93 kg (corresponding to 10 mol) of aniline, and the mixture was stirred at 80 ° C. for 5 hours. A mixed solution was prepared. 1.62 kg of formalin (37% aqueous solution) was charged into a 5-liter flask, heated to 90 ° C., and the resulting mixed solution was added little by little over 30 minutes. After the addition was completed, the temperature was maintained at the reflux temperature for 30 minutes, and then the pressure was reduced to 66.661 hPa or less at 100 ° C. to remove water to obtain an aniline-modified phenol resin. The obtained aniline-modified phenol resin had a softening point of 89 ° C. and (ring and ball method).

Example 1 In a flask equipped with a stirrer, a reflux condenser and a thermometer, 9
After adding 16.3 parts of 2% paraformaldehyde and 85.0 parts of water and dissolving paraformaldehyde, 187.0 parts of benzoguanamine, 1.0 part of oxalic acid and 140 parts of methyl isobutyl ketone were added, and the mixture was added at 60 ° C. The reaction was carried out for 2 hours and further at 100 ° C. for 2 hours, and then the solvent was removed by heating. The end point of the desolvation was determined when the temperature in the flask reached 120 ° C., and upon reaching the end point, 80 parts of methyl ethyl ketone was added to obtain an amino resin varnish having a heating residue of 186.9 parts. The obtained amino resin has a triazine nucleus 1
The mole is 0.4 mole of the methylene bond and the mole of both the methylol group and the alkyl ether group is 0 mole ( ¹³ C—N
According to MR analysis, the same applies hereinafter).

A molding material was prepared by blending 50 parts of the obtained amino resin varnish, 85 parts of the aniline-modified phenol resin obtained above and 15 parts of the phenol resin obtained above. This molding material is filled into a mold having an inner size of 120 × 80 × 15 mm, and the pressure is reduced to 1 at a pressure of 66.7 hPa or less.
A molded article was produced by heating and pressing at 80 ° C. and a pressure of 1.96 MPa for 1 hour.

Example 2 An amino resin varnish was obtained in the same manner as in Example 1 except that 92% paraformaldehyde was changed to 21.2 parts. The obtained amino resin had a methylene bond of 0.6 mol, and the methylol group and the alkyl ether group were all 0 mol with respect to 1 mol of the triazine nucleus.

A molded article was produced in the same manner as in Example 1 except that 50 parts of the obtained amino resin varnish was blended.

Comparative Example 1 In a flask equipped with a stirrer, reflux condenser and thermometer, 8
0% paraformaldehyde 75.0 parts, methanol 96
After 0.0 parts and 2.0 parts of a 50% aqueous sodium hydroxide solution were added to dissolve paraformaldehyde, 187.0 parts of benzoguanamine were added, and the mixture was reacted at 60 ° C. for 3 hours. Thereafter, 4.0 parts of 62% nitric acid was added, and
Allowed to react for hours. After the reaction, 2.0 parts of a 50% aqueous sodium hydroxide solution was added again to make the reaction solution alkaline,
Heated under reduced pressure of 66.7 hPa,
Concentrated until reaching 10 ° C. The temperature in the flask is 110
At the same time as the temperature reached ° C, 125 parts of methyl ethyl ketone were added to obtain 266 parts of an amino resin varnish having a heating residue. The obtained amino resin contained 0.1 mol of a methylene bond, 0.3 mol of a methylol group, and 1.7 mol of an alkyl ether group per 1 mol of the triazine nucleus.

A molded article was prepared in the same manner as in Example 1 except that 50 parts of the obtained amino resin varnish was blended.

Comparative Example 2 A molded article was produced in the same manner as in Example 1 except that no amino resin was used.

The molded product obtained as described above was examined for flame retardancy and for the presence or absence of voids as follows. Table 1 shows the results. Flame retardancy: Evaluated at a thickness of 3.6 mm according to UL-94. Voids: The number of voids in the obtained cured product was observed with an optical microscope at a magnification of 100, and the presence or absence of voids having a pore diameter of 10 μm or more was observed.

[0027]

[Table 1]

[0028]

The amino resin of the present invention is free from voids during heat molding, has excellent flame retardancy, and is suitable as a flame-retardant molding material.

Claims (5)

[Claims] 1. An initial condensate obtained by reacting a melamine with an aldehyde, wherein a methylene bond is 0.1 to 1.0 with respect to 1 mol of a structural unit containing a triazine nucleus.
Amino resin in which the total amount of methylol groups and alkyl ether groups is 1.0 mol or less. 2. The amino resin according to claim 1, wherein the melamine is benzoguanamine. 3. The method according to claim 1, wherein 0.1 to 1.0 mol of the aldehyde is reacted with 1 mol of the melamine under acidic conditions.
Or the method for producing an amino resin according to item 2. 4. The method for producing an amino resin according to claim 3, wherein the melamine and the aldehyde are reacted in a ketone-based solvent. 5. A molding material containing the amino resin according to claim 1 or 2.