JPH06228255A - Production of biodegradable phenolic resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin excellent in heat resistance and biodegradability and useful as a heat-resistant material free from environmental pollution by reacting a phenolic compound with a sugar compound and further reacting the unreacted phenolic compound with formalin. CONSTITUTION:A phenolic compound such as phenol or cresol is reacted with a sugar compound in a molar ratio of 1:0.1-0.5 in the presence of an acidic catalyst such as sulfuric acid or hydrochloric acid, and the unreacted phenolic compound is subsequently reacted with formaldehyde in an amount of <=50mol.% based on the amount of the unreacted phenolic compound to obtain the objective resin.

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 make it possible to use a biodegradable polymer material even in a field where heat resistance is required.

[0004]

[Means for Solving the Problems] That is, according to the present invention, phenols and sugars are reacted in the presence of an acidic catalyst at a ratio of 0.1 to 0.5 mol of sugar to 1 mol of phenol. And a method for producing a phenol resin having biodegradability, characterized in that the amount of formaldehyde added is 50 mol% or less with respect to unreacted phenols when reacted with formaldehyde under an acidic catalyst. Is.

[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.

When phenols and sugars 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 glucose and fructose are produced by hydrolysis of sugars with an acid, and these react with phenols because they have an aldehyde and a carbonyl group in the molecule. 1 mol of sugar acts as 2 mol by hydrolysis. Acidic catalysts used for the reaction of phenols and sugars include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, or paratoluenesulfonic acid, benzenesulfonic acid, oxalic acid, maleic acid, formic acid, acetic acid, succinic acid. Organic acids such as can be used.
When sugars and phenols are reacted under an acidic catalyst and dehydrated under vacuum, a reddish brown to blackish brown novolac type phenol resin is obtained. This resin, like a normal novolac type phenol resin obtained by reacting phenols and aldehydes under an acidic catalyst, is chemically three-dimensionally heated by adding a formaldehyde donor such as hexamethylenetetramine and paraformaldehyde. 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. However, this patent does not disclose any findings regarding biodegradability. Further, in the case of reacting with formaldehyde after the reaction between phenols and sugars, when the formaldehyde to be added is 0.5 mol or more relative to 1 mol of phenols, it is generated. The bonds involved in biodegradability in the product are reduced, and the biodegradability of the resin becomes poor. Based on such knowledge, the amount of formaldehyde added after the reaction of phenol and sugars is preferably 50 mol% or less with respect to the unreacted phenols. Particularly preferably,
It is 20 to 30 mol%. When it is 30 mol% or more, as described above, the biodegradability tends to decrease. 20
If it is less than mol%, the biodegradability will not be affected, but the properties of the cured product, especially the heat resistance, will decrease, and depending on the application, the properties may not be satisfied. With respect to the charging ratio of phenols and sugars, if the sugars are 0.1 to 0.5 mol per mol of the phenols, a good resin for carrying out the present invention can be obtained. When this ratio is less than 0.1 mol of sugar relative to 1 mol of phenol, the chemical three-dimensional structure after curing of the obtained resin becomes dense and biodegradability is deteriorated. On the other hand, when the amount of sugar is 0.5 mol or more per mol of phenol, unreacted sugar is increased and it is difficult to obtain a resin having good mechanical properties and heat resistance.

[0008]

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 kettle equipped with a condenser and a stirrer was prepared, and 94 g of phenol (1 mol) and 102.6 g of sugar (0.
(3 mol), pure water (47 g) and concentrated sulfuric acid (0.2 g) were charged, and then the temperature was gradually raised. Phenol and sugar were reacted for 180 minutes at an internal temperature of 100 ° C., and then dehydration was carried out at atmospheric pressure to remove water. The yield at this point was 175 g,
Unreacted phenol was 23%. 37% formalin 10.5g (30% to unreacted phenol)
(Mol%) was sequentially added, and the reaction was further performed at 96 ° C. for 120 minutes. Next, this was neutralized with slaked lime. This is dehydrated under vacuum and biodegradable phenol resin 1
55 g was obtained. Example 2 A reaction kettle equipped with a condenser and a stirrer was prepared, and 94 g (1 mol) of phenol and 68.4 g (0.2
Mol) and 18.8 g of paratoluenesulfonic acid, and then gradually heated. Phenol and sugar were reacted for 240 minutes at an internal temperature of 100 ° C., and then dehydration was carried out at atmospheric pressure to remove water. The yield at this point was 123 g, and the unreacted phenol was 31%. 37 to this
% Formalin 6.6 g (2 for unreacted phenol)
0 mol%) was added successively, and the reaction was further carried out at 96 ° C. for 120 minutes. Next, this was neutralized with slaked lime. This was dehydrated under vacuum to obtain 126 g of biodegradable phenol resin.

Comparative Example 1 A reaction vessel equipped with a condenser and a stirrer was prepared, and 94 g (1 mol) of phenol and 9.4 g of oxalic acid were charged therein, and then the temperature was gradually raised. Inner temperature is 9
After reaching 6 ° C., 64.8 g (0.8 mol) of 37% formalin was sequentially added, reacted for 120 minutes, and then dehydrated under vacuum to obtain 97 g of novolac type phenol resin.
Got << Comparative Example 2 >> A reaction vessel equipped with a condenser and a stirrer was prepared, and 94 g (1 mol) of phenol and 17.1 g (0.0
(5 mol), 47 g of pure water and 0.2 g of concentrated sulfuric acid were charged, and then the temperature was gradually raised. Phenol and sugar were reacted for 180 minutes at an internal temperature of 100 ° C., and then dehydration was carried out at atmospheric pressure to remove water. The yield at this point was 98 g and the unreacted phenol was 74%. To this, 18.7 g of 37% formalin (30 mol% relative to unreacted phenol) was sequentially added, and further reacted at 96 ° C. for 120 minutes. Next, this was neutralized with slaked lime. This was dehydrated under vacuum to obtain 78 g of phenol resin.

Comparative Example 3 A reaction vessel equipped with a condenser and a stirrer was prepared, and 94 g (1 mol) of phenol and 20 g of sugar were added thereto.
After charging 5.2 g (0.6 mol), 47 g of pure water and 0.2 g of concentrated sulfuric acid, the temperature was gradually raised. Phenol and sugar were reacted for 180 minutes at an internal temperature of 100 ° C., and then dehydration was carried out at atmospheric pressure to remove water. The yield at this point is 26
It was 3 g, and the unreacted phenol was 10%. To this, 6.7 g of 37% formalin (30 mol% relative to unreacted phenol) was sequentially added, and further 1
The reaction was carried out for 20 minutes. Next, this was neutralized with slaked lime. This was dehydrated under vacuum to obtain 155 g of phenol resin. << Comparative Example 4 >> A reaction vessel equipped with a condenser and a stirrer was prepared, and 94 g (1 mol) of phenol and 102.6 g (0.1
(3 mol), pure water (47 g) and concentrated sulfuric acid (0.2 g) were charged, and then the temperature was gradually raised. Phenol and sugar were reacted for 180 minutes at an internal temperature of 100 ° C., and then dehydration was carried out at atmospheric pressure to remove water. The yield at this point was 175 g,
Unreacted phenol was 23%. 37% formalin 20.9g (60% to unreacted phenol)
(Mol%) was added successively, and further reaction was carried out at 96 ° C. for 120 minutes. Next, this was neutralized with slaked lime. This was dehydrated under vacuum to obtain 161 g of phenol resin.

As described above, Examples 1, 2 and Comparative Examples 1, 2,
Each of the phenol resins obtained in 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 / 1 hour. It was cured at. The obtained cured product was embedded in soil, and after 6 months, the condition was observed and the weight reduction was measured. Moreover, the thermal decomposition start temperature of the obtained cured product was measured. The results are shown in Table 1.
Since Comparative Example 1 does not use sugar, biodegradability cannot be obtained. In Comparative Example 2, since the ratio of sugar to phenol was low, the chemical three-dimensional structure after curing of the obtained resin became dense and the biodegradability was lowered. Comparative Example 3
The heat resistance decreased because the ratio of sugar to phenol was too high. In Comparative Example 4, since the amount of formaldehyde added was large, the number of bonds contributing to the biodegradability in the product was reduced and the biodegradability was lowered. The phenolic resins obtained in Examples 1 and 2 showed no change even after being left in the air for 6 months. Further, it is understood that these resins have a thermal decomposition initiation temperature of 300 ° C. or higher and have sufficient heat resistance.

[0012]

[Table 1]

[0013]

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 (1)

[Claims] 1. Phenols and sugars in the presence of an acidic catalyst, 0.1 to 0.5 sugars per mol of phenols.
Phenol having biodegradability, characterized in that the amount of formaldehyde to be added is 50 mol% or less based on the unreacted phenols when reacted at a molar ratio and then reacted with formaldehyde under an acidic catalyst. Resin manufacturing method.