JP3016465B2 - Water-soluble phenolic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble water-soluble phenolic resin composition used as a binder for molding sand for producing castings. More specifically, the present invention relates to a water-soluble phenol resin composition that can reduce a peculiar odor (mainly, formaldehyde odor) generated when the water-soluble phenol resin is cured by an organic ester curing agent.

[0002]

2. Description of the Related Art In order to produce a casting, a mold is required, but the mainstream of the method for producing the mold is an organic self-hardening mold molding method, which comprises molding sand, an organic binder, and the binder. Is kneaded with a curing agent composition for curing the resin, and the mold is removed. In this method, the organic binder cures at the same time as the kneading with the curing agent composition is started.

A water-soluble phenol resin is widely used as a main component of an organic binder used in such an organic self-hardening molding method, and γ-butyrolactone is used as a curing agent composition at this time. Organic esters such as are widely used (JP-A-50-130627,
JP-A-58-154433, JP-A-58-154
434, etc.).

However, when a water-soluble phenol resin is cured with an organic ester, formaldehyde is inevitably formed as a by-product, so that when forming a mold, formaldehyde odor is generated in the molding process (from the kneading process to the removal process). Furthermore, even during the pouring step in which molten metal such as pig iron is poured into the mold, formaldehyde odor is generated, and there is a problem that the working environment is deteriorated and pollution is caused.

[0005] Therefore, it has been proposed to add an organic nitrogen-containing compound such as urea or amine as a formaldehyde scavenger to an organic binder containing a water-soluble phenol resin as a main component (Japanese Patent Application Laid-Open No. 5-105). 192737). According to this, the organic nitrogen-containing compound reacts with the generated formaldehyde to form a Schiff base, whereby the amount of formaldehyde scattered outside the mold can be significantly suppressed.

[0006]

By the way, in order to prevent formaldehyde odor from being perceived by workers,
It is necessary to keep the formaldehyde concentration in the working environment below the odor threshold.

However, since the odor threshold of formaldehyde is very low, even if a formaldehyde scavenger is added to an organic binder as disclosed in Japanese Patent Application Laid-Open No. 5-192737, the formaldehyde concentration in the working environment is reduced. There was a problem that formaldehyde could not be sufficiently captured so as to be below the odor threshold.

For this reason, it is conceivable to add a fragrance to the organic binder to mask the formaldehyde odor.

However, formaldehyde (boiling point-21)
° C) has a very high volatility and, as mentioned above, a very low odor threshold, and because of its characteristic off-flavor, it has a more volatile and lower odor threshold than formaldehyde However, there is a problem that there is no fragrance substance capable of masking a peculiar off-odor. Further, the pH of the water-soluble phenol resin composition as a binder is about 12 which is alkaline, and there is a problem that the amount of fragrance stable under such alkaline conditions is very small.

[0010] Therefore, what kind of fragrance is added to the water-soluble phenol resin composition as a binder used in the organic self-hardening mold making method to effectively mask formaldehyde odor is as follows. Until now, no consideration has been given, and no fragrance has been formulated to mask the formaldehyde odor.

The present invention is intended to solve the problems of the prior art as described above. In a self-hardening mold molding method using a water-soluble phenol resin as an organic binder, a kneading step, a removing step, Another object of the present invention is to provide a water-soluble phenol resin composition containing a fragrance component capable of effectively masking a peculiar off-odor (mainly formaldehyde odor) generated in a mold burning step.

[0012]

Means for Solving the Problems The present inventors have found that the above object can be achieved by adding a specific perfume component and a surfactant to a water-soluble phenol resin composition, and completed the present invention. It led to.

That is, the present invention relates to a water-soluble phenol resin containing a water-soluble phenol resin, a component (A), a specific fragrance component and a component (B) a polyoxyethylene-added anionic or nonionic surfactant. A composition is provided.

Hereinafter, the present invention will be described in detail.

The water-soluble phenolic resin composition of the present invention comprises:
It contains a water-soluble phenol resin which is cured with an organic ester curing agent such as γ-butyrolactone in a state of being dissolved in water, and has an alkaline pH of about 12.

The water-soluble phenol resin used in the present invention is not particularly limited, and those conventionally used in a self-hardening molding method can be used. For example, phenol, cresol, resorcinol, 3,5
Phenols, including xylenol, bisphenol A, and other substituted phenols, in an aqueous alkali metal hydroxide solution, particularly preferably in an aqueous potassium hydroxide solution, with aldehydes such as formaldehyde, acetaldehyde, and furfural aldehyde; Can be used a resin obtained by reacting with formaldehyde alone.

The content of the water-soluble phenol resin in the composition is not particularly limited, but from the viewpoint of handleability, it is generally preferable that the viscosity be 1000 cps or less, and particularly preferably, the viscosity is 500 cps or less. Amount.

In the present invention, as the specific fragrance component of the component (A), at least one selected from the following alcohols, ketones, esters and ethers is used. These fragrance components are relatively stable under alkaline conditions of about pH 12, and can effectively mask formaldehyde odor.

Alcohols Tetrahydrolinalool / 3,7-Dimethyloctan-3-ol Dimethylbenzylcarbinol Phenylethyldimethylcarbinol (1,1-Dimethyl-3-phenylpropane-1-ol) Ketones α- And β-Damasenone (α-, β-Damascenone / 2,6,6-Trimethyl-trans-1-croton
yl-1,3-cyclo-hexadiene) camphor (Camphor / 1,7,7-Trimethyl-bicyclo (2,2,1) -2-heptanon
e) Celestlide / 4-Acetyl-6-tert-buthyl-1,1-dimethylind
an) Tentalome (Tentarome / 6-Acethyl-1,1,2,4,4,7-hexamethyltetrahy
dro-naphtalene) Musk ketone (Musk ketone / 2,6-Dinitro-3,5-dimethyl-4-acethyl-te
rt-buthylbenzene) esters Furuteito ^{(Fruitate / Tricyclo [5,2,1,0 2,6]} -decane-2-carboxyli
c acidalkyl (C1-4) ester) tert-butylcyclohexyl acetate pt-butylcyclohexyl acetate cedryl acetate dimethylbenzylcarbyl acetate ethers ambroxane (Ambroxan / 8-α-12-Oxide- 13,14,15,16-tetranorlabdan
e) Cedryl methyl ether Eucalyptol / 1,8-Epoxy-p-menthane Diphenyl oxide Galaxolide / 1,3,4,6,7,8-Hexahydro-4,6 , 6,7,8-hexame
thyl-cyclopenta-2-benzopyran) Neroline bromeria / β-Naphthol ethyl ether Nerolin yara yara / β-Naphthol methyl ether Herboxane (Herboxane / 2-Buthyl-4,4,6-trimethyl-1) , 3-dioxane) Lime oxide / 2-Isopropenyl-5-methyl-5-vinyltetrahyd
ro-furan) Limetol (Limetol / 2,5,5-Trimethyl-2-vinyltetrahydro-pyran) Linalool oxide / 2-Hydroxyisopropyl-5-methyl-vinylt
etrahydro-furan) Rose oxide / 2- (2-Methyl-1-propenyl) -4-methyl-tetra
hydro-pyran) Acetal E./Mixed acetal (2-phenylethyl) -1-ethoxyeth
ane) Phenylacetaldehyde dimethyl acetal.

Among these fragrance components, a boiling point of 21 at normal pressure
Tetrahydrolinalool, camphor, eucalyptol, harboxane, lime oxide, limetol, linalool oxide and rose oxide having a temperature of 0 ° or less have a strong and highly diffusible odor, and therefore have a good formaldehyde odor masking ability. Demonstrate. In particular, it is effective in masking formaldehyde odor in a relatively low temperature mold (particularly at the time of kneading) before pouring into the mold.

The α, β-unsaturated ketones α-β
Alternatively, β-damasenone and tentalom exhibit a high formaldehyde odor masking ability because they have a characteristic odor and high reactivity. These have a boiling point of 210
Since many of them have a boiling point higher than that of the aliphatic ester having a temperature of not more than ℃, there is an effect of continuously masking the formaldehyde odor during the mold kneading step, the mold removing step, and the pouring step. The reason for this has not been clarified at present, but is presumed to be due to the interaction with the water-soluble phenol resin.

If the content of the fragrance component of the component (A) in the water-soluble phenol resin composition is too small, the smell of formaldehyde tends to be insufficiently masked,
If the amount is too large, the fragrance of the fragrance may become too strong and the working environment may be deteriorated. Therefore, the amount is preferably 0.0001 to 5 to 100 parts by weight of the water-soluble phenol resin in the water-soluble phenol resin composition. 0 parts by weight, more preferably 0.001 to 2.0 parts by weight.

In the present invention, in order to solubilize the fragrance component of the component (A) in the water-soluble phenol resin composition,
As the component (B), a polyoxyethylene addition type anionic or nonionic surfactant is used. By using such a surfactant in combination, the perfume component of the component (A) can be efficiently solubilized in an alkaline water-containing composition having a pH of about 12.

Preferred examples of the polyoxyethylene addition type anionic surfactant include polyoxyethylene alkyl ether sulfates and polyoxyethylene alkylphenyl sulfates. Examples of the oxyethylene addition type nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl naphthyl ether, polyoxyethylene hydrogenated castor oil, polyoxyethylene abiethinyl alcohol, polyoxyethylene Preferred examples include ethylene alkyl thioether and polyoxyethylene-polyoxypropylene glycol.

It should be noted that even anionic or nonionic surfactants which are not of the polyoxyethylene addition type should not be used alone, because their perfume components are insufficiently solubilized. Moreover, it is difficult to use a cation or amphoteric surfactant alone because it does not effectively exhibit surface activity under highly alkaline conditions.

If the content of the surfactant of the component (B) in the water-soluble phenol resin composition is too small, the solubilization of the fragrance component of the component (A) becomes insufficient. It is expected that the properties and the filling property of the mold will be reduced, and that the surfactant itself will give off odor. Therefore, based on 100 parts by weight of the water-soluble phenolic resin in the water-soluble phenolic resin composition, the surfactant of the component (B) is used in an amount of preferably 0.01 to 10.0 parts by weight, more preferably 0.1 to 10.0 parts by weight. 5.0 parts by weight.

The water-soluble phenolic resin composition of the present invention comprises:
In addition to the water-soluble phenolic resin, the fragrance component of the component (A) and the surfactant of the component (B), various additives which can be generally added to water, a water-soluble organic solvent, and an organic binder are added as necessary. can do.

The water-soluble phenol resin composition of the present invention comprises:
It can be produced by adding a fragrance component of the component (A) and a surfactant of the component (B) to an aqueous solution of a water-soluble phenol resin, and uniformly mixing them by a known method.

As a method for producing a mold using the water-soluble phenol resin composition of the present invention, it is preferable to employ a so-called self-hardening mold molding method. Specifically, a casting mold, a water-soluble phenol resin composition of the present invention, and an organic ester-type curing agent are uniformly kneaded, and a mold can be prepared by removing the mold. In this case, Japanese Unexamined Patent Application Publication No.
As disclosed in Japanese Patent Publication No. 37, it is preferable that an organic nitrogen-containing compound is present during kneading.

Here, as the organic ester curing agent, those conventionally used as curing agents for water-soluble phenolic resins can be used. For example, lactones or monovalent or polyhydric compounds having 1 to 10 carbon atoms can be used. One or more organic esters derived from a dihydric alcohol and an organic carboxylic acid having 1 to 10 carbon atoms can be used. Among them, in the self-hardening molding method, γ-butyrolactone, propiolactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin and the like can be particularly preferably used.

The present invention can also be applied to a water-soluble phenol resin used in a gas-curable mold molding method using methyl formate or carbon dioxide gas as a curing agent.

[0032]

The water-soluble phenolic resin composition of the present invention contains a specific fragrance component as component (A) and a polyoxyethylene type anionic or nonionic surfactant as component (B). For this reason, when this composition is applied to a self-hardening mold molding method as an organic binder, a unique off-odor (mainly a formaldehyde smell) generated in the kneading step, the removal step, and the mold burning step is effectively and effectively obtained. It becomes possible to mask continuously.

[0033]

The present invention will be described below in detail with reference to examples. In the following examples, "parts" indicates parts by weight.

Examples 1 to 3 and Comparative Examples 1 to 3 Under the conditions of a temperature of 25 ° C. and a humidity of 60%, the components shown in Table 1 were uniformly kneaded, and the molds were removed to form molds. However, Comparative Example 3 is an example in which no fragrance was used.

[0035]

[Table 1] Component Amount (parts) Sand for mold (Fremantle) 100 Water-soluble phenolic resin 2 (solid content 49%, weight average molecular weight 2300, viscosity 100 cps) Fragrance formulations A to E 0.1 in Tables 2 to 6 ^* Polyoxy Ethylene-added nonionic surfactant 0.2 ^* (Emulgen 906, manufactured by Kao Corporation) Organic ester-based curing agent 20 ^* (Ethylene glycol diacetate) Note: The amount of "*" refers to water-soluble phenolic resin This is the amount used for 100 parts.

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5]

[0040]

[Table 6] Next, pig iron was poured into the obtained mold to produce a casting.
In this series of operations, the degree of masking of formaldehyde odor at the time of kneading, at the time of removing the mold, and at the time of pouring was organoleptically evaluated according to the following evaluation methods and evaluation criteria. Table 7 shows the results.

Evaluation Method of Formaldehyde Odor Masking A total of five odor specialist panelists evaluated at 25 ° C. and 60% RH according to the following evaluation criteria.

Evaluation criteria rank for masking Condition ◎: When the formaldehyde odor is well masked ○: When the formaldehyde odor is slightly felt but masked to such an extent that there is no practical problem Δ: When the formaldehyde odor is felt slightly strong or deteriorated When the scent of the fragrance is given ×: When the odor of formaldehyde is felt very strongly

[0043]

[Table 7] As is clear from Table 7, when the water-soluble phenolic resin compositions of Examples 1 to 3 were used, the off-flavor (mainly the formaldehyde odor) generated at the time of kneading and removing the mold and pouring into the mold was greatly reduced. It was possible to control and significantly improve the working environment.

On the other hand, the water-soluble phenolic resin composition of Comparative Example 1 using the perfume formulation D containing no perfume as the component (A) has insufficient masking during kneading and unmolding of the mold. The masking at the time of pouring was very inadequate. Also, with respect to the water-soluble phenolic resin composition of Comparative Example 2 using the perfume formulation E, the masking at the time of kneading the mold was insufficient. In particular, the masking at the time of removing the mold and pouring it into the mold was not sufficient. It was very inadequate. Furthermore, the masking of the water-soluble phenol resin composition of Comparative Example 3, which did not use any fragrance at all, was very insufficient in any case.

[0045]

According to the present invention, when the water-soluble phenolic resin composition of the present invention is used as an organic binder for a mold, an unpleasant odor (mainly a formaldehyde odor) generated at the time of molding the mold and pouring into the mold is greatly reduced by masking. Control, and the working environment can be significantly improved.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-192737 (JP, A) JP-A-5-212488 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 61/06 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A water-soluble phenol resin; (A) at least one fragrance component selected from the following group: tetrahydrolinalool, dimethylbenzylcarbinol, phenylethyldimethylcarbinol, α
-And β-damasenone, camphor, celestride,
Tentalome, musk ketone, fruity, ot-
Butylcyclohexyl acetate, pt-butylcyclohexyl acetate, ceryl acetate, dimethylbenzylcarbinyl acetate, ambroxane, ceryl methyl ether, eucalyptol, diphenyl oxide, galaxolide, nerolin promeria, nerolin yalala, herboxane, lime oxide, Water-soluble phenolic resin composition comprising: limetol, linalool oxide, rose oxide, acetal E and phenylacetaldehyde dimethyl acetal; and (B) a polyoxyethylene addition type anionic or nonionic surfactant. . 2. Component (A) is at least one selected from the group consisting of tetrahydrolinalool, α- and β-damasenone, camphor, tentarome, eucalyptol, harboxane, lime oxide, limetol, linalool oxide and rose oxide. The water-soluble phenol resin composition according to claim 1, which is one kind. 3. The polyoxyethylene addition type anionic or nonionic surfactant of the component (B) is a polyoxyethylene alkyl ether sulfate, a polyoxyethylene alkylphenyl sulfate, a polyoxyethylene alkyl ether, Polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl naphthyl ether, polyoxyethylene hydrogenated castor oil, polyoxyethylene abietinyl alcohol, at least selected from the group consisting of polyoxyethylene alkyl thioether and polyoxyethylene-polyoxypropylene glycol The water-soluble phenol resin composition according to claim 1, which is a kind. 4. The content of the component (A) is 0.0001 to 5.0 parts by weight and the content of the component (B) is 0.01 to 10.0 parts by weight based on 100 parts by weight of the water-soluble phenol resin. The water-soluble phenol resin composition according to any one of claims 1 to 3.