JPS58163543A - Production of casting mold for casting - Google Patents

Abstract

PURPOSE:To obtain a casting mold which can be easily dissolved in various solvents and has improved resistance to moisture by using a specific cumarone deriv. for the component to be combined with polyisocyanate in an urethane resin method and making combination use of a silane coupling agent. CONSTITUTION:a) The cumarone dervi. of the formula (n is 1-10 rational number), b) a polyisocyanate compd., and C) a silane coupling agent are used as essential components; the components (a) and (b) are contained at 25/75-75/25 weight ratio and are added at 1.0-3.0wt% to molding sand for a casting mold, and the component (c) is contained at about 0.1- about 1wt% based on the weight of the components (a) and (b) or about 0.2- about 2wt% based on the component (a). These components are cured. Here the component (a) forms a graphite structure like a phenolic resin at an extremely high temp. like a casting temp.; therefore, said component is resistant to heat and since the component has no hydrophilic groups, it has good resistance to moisture and is soluble in most of general purpose solvents except paraffinic solvents.

Description

[Detailed Description of the Invention] This book relates to a new 'tXg manufacturing method for foundry molds. Casting is carried out by adding a special device to the casting #II type fine sand as an essential ingredient! ! This relates to the so-called urethane resin no-bake method and urethane resin cold box method (hereinafter referred to as the urethane resin method).

The urethane resin method, which uses polyisocyanate as one of its main components, is basically a method of making a mold by curing this polyisocyanate through a reaction with active hydrogen in the other main component. As the isocyanate component, crude methylene bisphenyl diisocyanate is usually used.

On the other hand, as substances having active hydrogen, resol type phenol formaldehyde resins having dimethylene ether bonds and various polyol compounds are used.

Among these, phenol-formaldehyde resins are mainly used as binders for cast iron molds, and polyol compounds are mainly aliphatic polyols such as propylene glycol and their derivatives. It is used as a one-ring mixture for making one core of molds.

By the way, phenol-formaldehyde resin has some disadvantages, such as a rather low strength in normal state, poor heat resistance, limited solvents, and a significant decrease in strength in the presence of multiple sources. On the other hand, polyol compounds have drawbacks such as low scratch resistance and high moisture resistance.

In other words, the phenol/formaldehyde resin used in combination with a polyisocyanate compound mainly has the following formula. and m are each an integer of 0 or 1 or more, and are numbers that simultaneously satisfy 1+m≧1 and 17m≧1.

There is something called the dimethylene ether type or diphenylene ether type, which is shown in
The drawbacks mentioned above are noticeable.

In addition, alcohols can be cited as good solvents for this type of phenolic tree 1t (F), but alcohols originally contain active hydrogen, so if they react with isocyanate groups, they will inhibit performance, so they are not preferred. Tetrahydrofuran is another good solvent, but it is expensive and undesirable, so ketones such as Ikioi methyl ethyl ketone and isophorone are used mainly, and in order to make them even cheaper, Kijirol and "Turupetz" (Etsuo Standard Oil am The current situation is that aromatic hot-mixing solvents are used as diluting solvents.

Furthermore, since the phenol resin and the polyisocyanate compound are mixed in sand, it is impossible to mix them uniformly.
-0-CH2) is likely to absorb moisture where it remains, which is presumed to cause deterioration in various performances.

On the other hand, when combining a polyisocyanate compound and the polyol compound, it is necessary to dissolve it in a general-purpose solvent that does not have active hydrogen.
Since a polypropylene glycol-based compound is used, it has poor heat resistance (in fact, it is considerably worse than the phenol/formaldehyde resin mentioned above), and there are also many hydroxyl groups, ether bonds, or ester bonds that can cause ascites. It has high hygroscopicity to
The result is a decrease in strength, which renders the molds useless unless they are stored and stored at low temperatures.

However, in view of the various drawbacks of the conventional urethane resin method as described above, the present inventors developed a method using phenol.
As a result of intensive research to obtain a casting mold that can be easily dissolved in various solvents without reducing the inherent heat resistance of formaldehyde resin and has improved moisture resistance, we have discovered a material that meets these objectives. The present invention was completed by demonstrating that the chroman derivative represented by the formula (where n is a rational number from 1 to 10) is preferable.

That is, in the present invention, the chroman derivative represented by the formula (1) and the polyisocyanate compound are used as essential components in a weight ratio of 25/75 to 75/25, and these two components are mixed in a ratio of 1% to the foundry river sand. .0-3.0 overlay%
Another object of the present invention is to provide a method for manufacturing a foundry mold, which comprises adding a compound in a proportion of 100% and then curing it.

Here, the chroman derivative is obtained by the reaction of 2.2.4-trimethyl-4-(hydroxyphenyl)chroman and isopropenylphenol, is manufactured by Mitsui Toatsu Chemical Co., Ltd., and is a derivative of l'BP^-ZKJ. Although this chroman derivative is commercially available under the same name, it is heat resistant because it forms a graphite structure like phenolic resin at extremely high temperatures such as pouring temperature, and it has no parent wood group. Therefore, it has good moisture resistance and is soluble in most general-purpose solvents other than paraffin-based solvents.

In carrying out the method of the present invention, the chroman derivative itself must be diluted to have a melting point of 100±10°C (pole and ring method), but the viscosity in this case is usually 200 cps. Preferably 100
cps or less, and the more the active ingredient is, the more preferable it is, and it is usually within the range of 40 to 70%.

The diluent used for this purpose is one of the most important components, and care must be taken when selecting it, but in general, polar solvents containing viscous hydrogen react with isocyanate groups and reduce strength. Not only that, but it also causes slow curing, and in the case of non-polar solvents that do not have active hydrogen, on the contrary, it causes fast curing. As such a diluting solvent, Yoshin,
Typical examples include Kijiroll and the ``Tsurupets'' type.

The chroman derivatives can also be used in combination with phenolic compounds such as phenolic resins and bisphenol-A, making it even more suitable for cast iron mold blinds and odors that have a heat resistance of 1!1 N'. Heat susceptibility is provided. In this case, 5 to 15
When used at a concentration of about 1.5%, there is an advantage that even phenolic resins that cannot be dissolved in non-polar solvents can be dissolved through the chroman derivative.

On the other hand, when heat disintegration properties are required for use in light metals such as aluminum alloys, if the heat resistance of the chroman derivative itself is intentionally deteriorated, an aliphatic polyol may be mixed with the chroman derivative. In this case, the propylene glycol compound is usually soluble in general-purpose solvents of the same type as the chroman derivative, such as ketone-based and "Tsurupez"-based solvents. Recommended.

By the way, the method of the present invention using the chroman derivative as one of the essential components has the following advantages when compared to the conventional urethane resin method, which is mainly based on the curing method through the reaction of a polyisocyanate compound and the active hydrogen of a primary alcohol. However, since the curing speed inevitably becomes low, it is necessary to use a larger amount of curing accelerator.

As such curing accelerators, tin-based compounds such as tin, cobalt, manganese or manganese are preferred because they have a large specific effect, but more preferred are triethylenediamine,
Examples include tertiary amines such as triethanolamine, morpholine or triethylamine.

The amount of the accelerator to be used is 0.00% relative to the total weight of the chroman derivative solution and the polyincyanate solution, which are used as an essential part in carrying out the method of the present invention.
A proportion of 1 to 3% or a proportion of 0.2 to 6% based on the weight of the chroman derivative solution is sufficient to meet the working conditions at room temperature, but if the sand temperature or air temperature exceeds 30 ° C. , it may even be necessary to add a retarder.

Typical examples of such retarders include sulfuric acid, salicylic acid,
Examples include acids such as heptal acupuncture chloride or benzoyl chloride.

Additionally, the effect of adding a silane/camping agent is large, approximately 0.1-IN based on the total weight of the chroman derivative solution and polyisocyanate solution, or 0.12 to 2% based on the weight of the chroman derivative solution. It is already observed that the strength performance improves by 10 to 30% even with the addition of
Commercially available aminosilanes or glycidosilanes are preferred as the silane coupling agent serving as the strength-imparting aid.

The above-mentioned curing accelerator, retarder, and strength-imparting aid (silane coupling agent) may all be mixed in sand, or may be added to the Kliman derivative solution in advance.

On the other hand, crude methylene bisphenyl diisocyanate is a typical example of the polyisocyanate compound, and is usually used in the form of a 65-95% solution.

The present Tsurume method uses the various components listed above, particularly the chroman derivative and the polyisocyanate compound as essential components, in a weight ratio of 25/75 to 75, respectively.
/25, and these essential components are added in a range of 1.0 to 3.0% by weight to foundry mold river sand, and then hardened to obtain a mold.

Thus, the foundry mold obtained by the method of the present invention has excellent heat resistance and layer strength.

Next, the present invention will be explained in more detail with reference examples, examples, and comparative examples, but in the following, all % means overlapping %.

Reference Example 1 (Example of preparation of main ingredient) A chroman derivative having a melting point (the same applies hereinafter) of 100°C as measured by the Pall and Ring method was added to a mixed solvent of kijirol/ethylene glycol monoethyl ether-80/20 (weight ratio). Dissolved to make a 50% solution.

Next, to this chroman derivative solution, 2% triethylenediamine, 0.4% 6% tin octylate, and 0.5% T-glycidoxypropyltrimethoxysilane were added, based on the weight of the solution. A main ingredient was obtained by adding the ingredients in different proportions and thoroughly mixing them. Hereinafter, this will be abbreviated as the main agent-^.

Reference #12 (same as above) The chroman derivative used in Reference Example 1 was replaced with chroman derivative/
A solution containing dipropylene glycol in a ratio of 60/40 (weight ratio) was heated to 120°C and dissolved in [Tsurupez #1001 to make a 50% concentrated solution, and then added to this solution. Based on the weight, 3% hexamethylenetetramine and 10% [Varka, 5P-285J (xylene resin modified phenol resin manufactured by Dai2 Nippon Ink Chemical Industry Co., Ltd.; 10ON concentration, viscosity [75000 cps)] were added for 1 dark test. After the reaction, it was cooled to room temperature, and further 1.5% of the weight of the chroman derivative-containing fs-sister was added.
of triethylenediamine and 0.5% of T-aminopropyltrimethoxysilane were added and thoroughly mixed to obtain a base material having a viscosity (Pluck Field viscosity at 25°C - S) of 80 cpa. Below, this is the main ingredient.
It is abbreviated as B.

Reference Example 3 (Same as above) A main ingredient was obtained by processing in the same manner as in Reference Example 1, except that triethylenediamine and tin octylate were completely omitted.

Hereinafter, this will be referred to as main ingredient-C.

Reference Example 4 (Preparation example of main ingredient for comparison) Consisting of adipic acid, phthalic acid, trimethylol and propylene glycol, hydroxyl group m = 2407, and viscosity 15000
CPS, a saturated polyester polyol manufactured by Ichikawa, was added to pheasant to prepare a solution with a concentration of 5094.

The polyol solution is then added with 2
% triethylenediamine, 5% T-aminopropyltrimethoxysilane and 6% cobalt naphthenate.
．． 8% was added and thoroughly mixed to obtain a base material with a viscosity of 5 Qcps (hereinafter, this will be abbreviated as base material-D).

Reference Example 5 (same as above) rresl described in US Pat. No. 3,409,579
According to the manufacturing method of nAJ, first 1014g of phenol
, 720 g of 91% paraformaldehyde, 15 g of 8% zinc naphthenate, and 120 liters of benzene were charged.
After 3 dark reactions at 103°C and then removing water and benzene, 1O-1 of benzene was added again to
50 mJ of diethylene glycol dimethyl ester was added and reacted at 103°C for 6 hours.

After the water and benzene are removed again,
Isophorone/[Tsurupets #100 J-1/1
(weight ratio) to obtain a benzyl ether type phenol tree solution with a concentration of 50%. Next, this solution was cooled to a solid state, and then 1% N- β-(aminoethyl)-T-aminopropyltrimethoxysilane', 2% triethylenediamine and 0.6% of 6% tin octylate were added and thoroughly mixed to obtain a base material having a viscosity of 50 cpa. Hereinafter, this will be abbreviated as main agent-E.

Reference Example 6 (Target) A main ingredient was obtained in the same manner as in Reference Example 5, except that triethylenediamine and tin octylate were completely omitted.

Hereinafter, this will be abbreviated as main agent-F.

Examples 1 to 3 and Comparative Examples 1 to 3 First, 3000 g of Fremantle sand with a sand temperature of 9°C has a revolution of about 1001 PII and a rotation of about 200 PII! I.P.I.
ll mixer, and while stirring, add each main ingredient obtained in Reference Examples 1 to 6 separately in the proportions listed in Table 1, mix for 30 seconds, and then mix as listed in Table 1. 11 in advance like 11
1 millionate obtained by dissolving in 00J? IR-1
00J (crude methylene bisphenyl diisocyanate manufactured by Nippon Polyurethane Industry ■; hereinafter abbreviated as C-1101) was added and kneaded again for 30 seconds.

Immediately after the kneading was completed, the compressive strength of each of the molds thus obtained was measured at 50 diameters and 50 lengths over time, and the results were as follows. They are summarized in Table 2.

゛ - In the case of Example 3 and Comparative Example 3, although triethylamine gas was passed through for 10 seconds for curing, all operations above 0 were carried out under the conditions of 10°C x 55% RH, and the storage conditions were The temperature was also 10° C. x 50 to 60% RH.

On the other hand, the moisture resistance strength and heat collapse resistance (heat resistance) were also measured for each of the obtained molds, and the moisture resistance strength was
The strength was compared in an atmosphere of 30°C x 90% RH, and the strength was compared at 450°C for 10 minutes.8. ．． 3 at 00℃
After being left for a minute, the specimen is immediately placed on a 10 mesh sieve and placed on a rotary tube vibrator to abrade the test piece until it is completely abraded.The longer the time, the higher the heat resistance. The results of both these tests are summarized in the same table.

As is clear from the results in Table 1 and Table 2, when the method of the present invention is followed, the moisture resistance strength, which is the first objective of the present invention, is not limited to the absolute value, but also the strength after 24 hours of standing (in the table). Even the rate of decrease when comparing the "compressive strength" section in Section III) is very superior, and the heat resistance is also almost the same or better. .

Patent applicant: Dainippon Ink and Chemicals Co., Ltd. Amendment (spontaneous) 1. Indication of the case 1982 Patent - No. 47601 2. Name of the invention Method for manufacturing foundry molds 3. Case of the person making the amendment Relationship with Patent applicant 3-35-58 Sakashita, Itabashi-ku, Tokyo 114 (2
881 Dainippon Ink & Chemicals Co., Ltd. Representative: Shigeru Mura Kuni 4 Agent: 3-7-20 Nihonyoko, Chuo-ku, Tokyo 103 Dainippon Ink & Chemicals Co., Ltd. Telephone: Tokyo (03) 272-4511 (Main representative) ) and "Detailed Description of the Invention" Column 6, Contents of Amendment (2) The description in the fourth to second lines from the bottom of the first line of the specification is corrected as follows.

``, and more specifically, a specific chroman derivative is used in combination with a polyisocyanate compound in a specific ratio, and a silane coupling agent is used in a specific range,
A specific amount of these kings is added to foundry sand as an essential component.

"Conductor, polyisocyanate compound, and silane coupling agent are essential components, and the weight ratio of chroman derivative and polyisocyanate compound is 25/75 to 75/25, and the weight ratio is 1.0 to 1.0 to foundry sand. The silane coupling agent is added in an amount of about 0.1 to 3.0% by weight, and the silane coupling agent is added in an amount of about 0.1 to
It is used in an amount of about 11% by weight, or about 0.2 to about 2% by weight based on this chroman derivative.
4) The statement in lines 13-14 on page 8 is corrected as follows.

Furthermore, when carrying out the method of the present invention, the addition of the silane coupling agent has a remarkable effect, and the silane coupling agent is combined with the chroman derivative, which is another essential component of the present invention. (5) The statement on the second line of page 9 is corrected as follows.

rOn the other hand, in carrying out the method of the present invention, the essential components -
- The polyisocyanate compound used as one is Crude 1. (6) The description in lines 16 to 8 is corrected as follows.

First, the chroman derivative and the polyisocyanate compound were mixed in a weight ratio of 25/75, respectively.
The silane coupling agent was used in a ratio of ~75/25, and the silane coupling agent was added in an amount of about 0 to the total weight of each solution of these chroman derivatives and polyiso, ・I-1・compound.
．． These three essential components are used in foundry molding sand in a proportion of either 1 to about 1% or about 0.2 to about 2% based on the weight of the chroman derivative solution! ,0~j
, , - (7) Insert the following sentence (Reference Example 7) between lines 10 and 11 of Part 12 of the specification.

"Reference Example 7 (same as above) - T A base agent was obtained in the same manner as in Reference Example 1 except that no glycidoxypropyltrimethoxysilane was used.

Hereinafter, this will be abbreviated as main agent-G.

Reference Example 8 (same as above) A base material was obtained in the same manner as in Reference Example 2 except that triethylenediamine and T-aminopropyltrimethoxysilane were not used at all. Hereinafter, this will be abbreviated as main agent-H. j (81 The statement on the 15th line of the same page is corrected as follows.

(9) The statement on page 13, line 4 of the specification is corrected as follows.

"In addition, in the case of Example 3, Comparative Example 3, and Comparative Example 5,
Triethyla' / Amended Claim 1 The chroman derivative represented by formula C, the polyisocyanate compound, and a silane coupling agent are essential components, and the chroman derivative and the polyisocyanate compound are 25/75 to 75. '1114 method for foundry molds, characterized by using a yoke 1 of 1.0 to 3.0% overlapping with river sand for foundry castings at a standing ratio of /25, and then hardening.

Claims (1)

[Scope of Claims] (However, n in the formula shall be a rational number of 1 to 10.) 25/75 to 75/25, containing a chroman derivative represented by the formula and a polyisocyanate compound as essential components. 1. A method for manufacturing foundry castings, which comprises adding 1.0 to 3.0% by weight of river sand for foundry castings at a weight ratio of 1.0 to 3.0% by weight, and then hardening the sand. to\,