JPH06248040A - Production of biodegradable phenol resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin, excellent in heat resistance and environmental pollution resistance and useful as moldings, etc., by reacting phenols with a mixture of sugars, etc., in a specific proportion in the presence of an acidic catalyst. CONSTITUTION:This phenol resin is obtained by reacting (A) 100 pts.wt. phenols with (B) 20-200 pts.wt. mixture of (i) sugars such as white sugar with (ii) starches such as corn starch [at preferably (10/90) to (90/10) mixing weight ratio of the components (i)/(ii)] in the presence of an acidic catalyst such as p-toluenesulfonic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermosetting resin having biodegradability. More specifically, the present invention relates to a method for producing a thermosetting resin which is rapidly decomposed after use by imparting biodegradability and does not adversely affect the environment.

[0002]

2. Description of the Related Art In recent years, environmental pollution due to industrial waste has become a serious problem. Such conventional wastes are mainly composed of synthetic resins, but these are hardly decomposed by microorganisms and remain semipermanently in soil, seawater, or water. This has increased environmental pollution and made the problem more serious. To solve these problems,
Biodegradable plastics are attracting attention today. However, the biodegradable plastics that have been developed so far are thermoplastic, and thus their use has been limited in fields requiring heat resistance.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been completed by studying to enable the use of a biodegradable polymer material even in the field where heat resistance is required.

[0004]

That is, according to the present invention, a mixture of phenols and sugars and starches is added to 2 parts of the mixture of sugars and starches per 100 parts by weight of phenols.
The present invention relates to a method for producing a phenol resin having biodegradability, which comprises reacting in the presence of an acidic catalyst at a ratio of 0 to 200 parts by weight.

[0005]

The phenols used in the present invention include phenol, cresol, xylenol, catechol, resorcin, alkylphenols, bisphenols and mixtures thereof. Furthermore, hydroquinone, aniline, urea, melamine, cashew nut shell oil and the like can be used within a range that does not affect the physical properties. Sugars, whose main component is generally sucrose, can be classified into cane sugar and sugar beet sugar. In addition, depending on the manufacturing process, sucrose containing sugar and sucrose, and depending on the degree of purification, raw sugar
It is classified into refined sugar, white sugar, brown sugar and brown sugar depending on the hue, or powdered sugar, lump sugar and rock sugar depending on the processing form. Any of these can be used in the present invention.

[0006] Starch is a polysaccharide having an α1-4 linked D-glucan as a main chain, which is present in granular form in cells as the most important storage nutrient of plants. Starch photosynthesized from carbon dioxide and water during the daytime is hydrolyzed into soluble sugars at night and is transported to each storage location where it can be converted into granular storage starch. Exists. Starch granules can be obtained by crushing a raw material plant (potato, corn, wheat, etc.) with cold water and allowing it to settle from a solution from which solids have been removed. Starch exists as particles, which are regarded as a kind of crystals in which molecules are regularly arranged and grown. When observed under a microscope, the shape and size differ depending on the raw material, and there are those that have a depression, and those that have a layered structure centered on it. Among the large starches,
There is potato starch, the diameter of which is around 0.1 mm, and the smaller one is rice starch granules, which are several μm. Starch is highly hygroscopic and contains 20% moisture in the air-dried state, and absorbs 35% moisture in moist air. Also,
It is insoluble in cold water, but in hot water the micelles collapse and the molecular spacing expands until it finally dissolves to form a bluish sol. At high concentrations, it solidifies on cooling and becomes a whitish gel. When starch is heated as it is, it loses water first, and at about 200 ° C, part of it is converted to dextrin. When heated with a dilute inorganic acid for a long period of time, it is hydrolyzed into D-glucose almost quantitatively through an intermediate product such as soluble starch, dextrin and maltose.

The main constituents of the starch granules are amylose, which is α1-4 linked D-glucan, and amylopectin, to which an α1-6 linked side chain is added. The ratio of the two differs depending on the raw material, and generally the amylopectin content is 70 to 80%. However, some cereals can reach up to 98% and, conversely, less than 30%. When the starch granules are swollen with hot water at 70 ° C., only amylose is dissolved and extracted. Amylose is 250 to 3
00 D-glucopyranose units consisted of α1-4 glucoside-bonded linear molecules, which tend to spiral. When α-amylase is allowed to act on amylopectin for a long time, it produces isomaltose together with maltotriose and maltotetraose.

As described above, various starches exist, but they can all be used in the present invention. In combination with a mixture of sugars and starches, it is possible to use aldehydes such as formaldehyde and ketones, which are used when synthesizing ordinary novolaks, within a range that does not affect the physical properties. However, when formaldehyde or the like is used, the mechanical properties and heat resistance are improved, but the biodegradability tends to decrease. When phenols and sugars and starches are heated under an acidic catalyst, they react with each other to form a resin. However, it hardly reacts under a neutral or alkaline catalyst. This is because sugars and starches are hydrolyzed by the acid. Sugars are hydrolyzed to produce glucose and fructose. Also, starch is decomposed into glucose, which is its structural unit, by hydrolysis,
Depending on the decomposition conditions, a mixture with various intermediate decomposition products is formed. The decomposition products from these sugars and starches react with phenols because they have aldehyde and carbonyl groups in the molecule.

The acidic catalyst used in the reaction of phenols with sugars and starches includes inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, or paratoluenesulfonic acid, benzenesulfonic acid, oxalic acid, maleic acid, formic acid, Organic acids such as acetic acid and succinic acid can be used. A mixture of phenols, sugars and starches is reacted under an acidic catalyst and then dehydrated under vacuum to obtain a reddish brown to blackish brown novolac type phenolic resin. This resin, like a normal novolac type phenol resin obtained by reacting phenols and aldehydes under an acidic catalyst, is added with a formaldehyde donor such as hexamethylenetetramine and paraformaldehyde, and chemically three-dimensionally heated. A crosslinked structure is formed and cured. It has already been reported in JP-A-58-55146 that the phenols and sugars react with each other under an acidic catalyst. The reaction between phenols and starches has also been reported in US Pat. No. 1,753,030 and US Pat. No. 1,923,321. However, there is no report on biodegradability in these patents.

If the charge ratio of the mixture of phenols and sugars and starches is 20 to 200 parts by weight of the mixture of sugars and starches to 100 parts by weight of phenols,
Good resins for practicing the invention are obtained. This ratio is less than 20 parts by weight of a mixture of sugars and starch with respect to 100 parts by weight of phenols, or vice versa.
When it is 0 part by weight or more, biodegradability is not affected, but a resin having good mechanical properties and heat resistance tends to be difficult to obtain. The weight ratio of sugars and starches to be reacted with phenols is preferably 10:90 to 90:10, and particularly preferably 40:60 to 60:40. If the weight ratio of starch exceeds 90%, the biodegradability of the obtained resin tends to be slightly lowered. On the contrary, the proportion of sugar is 90%
If it exceeds, mechanical properties of the obtained resin tend to be slightly deteriorated.

[0011]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples. Moreover, all "parts" and "%" described in the following examples show "parts by weight" and "% by weight". Example 1 A reaction vessel equipped with a condenser and a stirrer was prepared, and 100 parts of phenol, 30 parts of sugar, 30 parts of starch, and 5 parts of paratoluenesulfonic acid were charged therein, and the temperature was gradually raised. The reaction was carried out at an internal temperature of 130 ° C. while distilling off the produced water for 180 minutes. Then, the internal temperature was raised to 180 ° C. to complete the reaction. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This was dehydrated to 130 ° C. under normal pressure and then to 180 ° C. under vacuum to obtain 117 parts of biodegradable phenol resin.

Example 2 A reaction vessel equipped with a condenser and a stirrer was prepared, charged with 100 parts of phenol, 30 parts of sugar, 20 parts of starch and 5 parts of paratoluenesulfonic acid, and then gradually heated. . The reaction was carried out at an internal temperature of 130 ° C. for 180 minutes while distilling off the produced water. Then, the internal temperature was raised to 180 ° C. to complete the reaction. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This was dehydrated to 130 ° C. under normal pressure, and then dehydrated to 180 ° C. under vacuum to obtain 88 parts of biodegradable phenol resin. Example 3 A reaction vessel equipped with a condenser and a stirrer was prepared, charged with 100 parts of phenol, 50 parts of sugar, 50 parts of starch, and 5 parts of paratoluenesulfonic acid, and then gradually heated. The reaction was carried out at an internal temperature of 130 ° C. for 180 minutes while distilling off the produced water. Then, the internal temperature was raised to 180 ° C. to complete the reaction. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This was dehydrated to 130 ° C. under normal pressure and then to 180 ° C. under vacuum to obtain 135 parts of biodegradable phenol resin.

Comparative Example 1 A reaction vessel equipped with a condenser and a stirrer was prepared, 100 parts of phenol and 10 g of oxalic acid were charged therein, and the temperature was gradually raised. After the internal temperature reached 96 ° C., 69 parts of 37% formalin was sequentially added and reacted for 120 minutes, followed by dehydration reaction under vacuum to obtain 99 parts of novolac type phenol resin. Comparative Example 2 A reaction kettle equipped with a condenser and a stirrer was prepared, 100 parts of phenol, 80 parts of starch, and 5 parts of paratoluenesulfonic acid were charged therein, and then the temperature was gradually raised. Inner temperature 130
The reaction was carried out at 180 ° C for 180 minutes while distilling off the produced water. Then, the internal temperature was raised to 180 ° C. to complete the reaction. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This was dehydrated to 130 ° C. under normal pressure and then to 180 ° C. under vacuum to obtain 138 parts of a phenol resin.

Comparative Example 3 A reaction kettle equipped with a condenser and a stirrer was prepared, and 100 parts of phenol, 5 parts of sugar and 5 parts of starch were added thereto.
And 5 parts of paratoluenesulfonic acid were charged, and the temperature was gradually raised. The reaction was carried out at an internal temperature of 130 ° C. for 180 minutes while distilling off the produced water. The yield at this point was 96 parts and the unreacted phenol was 75%.
37.1 parts of 37% formalin was sequentially added thereto, and further reacted at 96 ° C. for 120 minutes. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This was dehydrated to 130 ° C. under normal pressure and then to 180 ° C. under vacuum to obtain 98 parts of a phenol resin. << Comparative Example 4 >> A reaction vessel equipped with a condenser and a stirrer was prepared, and 100 parts of phenol, 110 parts of sugar, 110 parts of starch,
After charging 5 parts of paratoluenesulfonic acid, the temperature was gradually raised. The reaction was carried out at an internal temperature of 130 ° C. for 180 minutes while distilling off the produced water. Then, the internal temperature is 180 ℃
The temperature was raised to and the reaction was completed. To this, 200 parts of methyl isobutyl ketone was added and diluted, followed by washing with water to remove the catalyst. This is dehydrated to 130 ℃ under normal pressure,
Then, dehydration reaction was performed under vacuum to 180 ° C. to obtain 198 parts of biodegradable phenol resin.

As described above, Examples 1, 2, 3 and Comparative Example 1,
The resin obtained in 2, 3, and 4 was pulverized into a fine powder, and 10 parts of hexamethylenetetramine was added to 100 parts of the resin, and 80 ° C / 1 hour + 110 ° C / 1 hour + 150 ° C /
Curing was carried out in 1 hour. The obtained cured product was buried in soil and the state after 6 months was observed to determine the weight reduction rate. Moreover, the thermal decomposition start temperature of the obtained cured product was measured. The results are shown in Table 1. Comparative Example 1 does not use biodegradability because sugars and starches are not used. Comparative Example 2 has a reduced biodegradability because it does not use sugar. In Comparative Example 3, since the ratio of the mixture of sugar and starch to phenol is low and formaldehyde is added to unreacted phenol, biodegradability cannot be obtained. Further, in Comparative Example 4, there was a tendency that the heat resistance was lowered because the ratio of the mixture of sugar and starch to phenol was too high. In addition, even if the resin of Examples 1, 2, and 3 was left in the air for 6 months, no change was observed. In addition, the resins of Examples 1, 2, and 3 have a thermal decomposition starting temperature of 300 ° C. or higher and have sufficient heat resistance.

[0016]

[Table 1]

[0017]

According to the present invention, a thermosetting biodegradable resin having biodegradability and excellent heat resistance can be obtained. The biodegradable phenolic resin obtained in the present invention can be used in a field requiring heat resistance, which cannot be used in conventional thermoplastic biodegradable plastics, and can be used in a wide range of applications of biodegradable resins. Is.

Claims (2)

[Claims] 1. A reaction between a phenol and a mixture of sugars and starch at a ratio of 20 to 200 parts by weight of a mixture of sugar and starch to 100 parts by weight of phenol in the presence of an acidic catalyst. A method for producing a phenol resin having biodegradability, which comprises: 2. The method for producing a phenol resin having biodegradability according to claim 1, wherein the mixing ratio (weight) of sugars and starch is 10:90 to 90:10.