JPS6024244A - Phenolic resin binder for shell mold - Google Patents

Abstract

PURPOSE:To provide a titled binder which is easily manufacturable, has no consolidating property and powders less by incorporating a silane coupling agent and amide having a low mol. wt. into resol type and novolak type phenolic resins so as to coexist therein and molding the mixture thereof. CONSTITUTION:A lubricant such as fatty acid amide or the like is compounded at about 0.5-10pts.wt. with 100pts.wt. mixture composed of a solid resol type phenolic resin and a solid novolak type phenolic resin using a combined catalyst of an amine catalyst and inorg. alkali catalyst. A silane coupling agent such as aminosilane and amide such as acrylamide having <500mol.wt. are mixed as a essential component therewith. The mixture is melted and is solidified and molded to a bead or bar shape having 0.5-7mm. diameter and 0.5-30mm. length. Such phenolic resin binder for dry hot coating permits easy automatic weighing and supplying and has good strength and the characteristic to cure quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a phenolic resin binder for dry hot cord molding, the main component of which is a solid resol type phenolic resin.

Resin-coated sand using the dry hot coating method using solid novolac type phenolic resin is made by mixing solid novolac type phenolic resin (hereinafter referred to as novolac) with heated sand.
Hexamethylenetetramine (
(hereinafter referred to as hexamine) to the resin at 10 to 15 times
t% as an aqueous solution, and further calcium stearate.

Resin-coated sand using such novolac-hexamine has excellent properties such as fast curing speed and fluidity, but the hexamine used in this method does not generate heat during mold making or pouring. When it decomposes, it generates nitrogen compounds such as ammonia or formaldehyde, causing environmental pollution, and when applied to cast iron or cast steel, the nitrogen compounds generated by the thermal decomposition of hexamine can cause gas defects such as pinholes or blowholes in cast products. There are disadvantages such as causing

In order to improve these drawbacks, attempts have been made to apply shell molding resins that do not contain any nitrogen or have a low nitrogen content to the dry hot foot method.

As a typical example, a method using a solid resol phenol resin has been proposed. The disadvantage of this method is that the resin curing speed is slower than that of Novo2Tsukuhexamine.
When cross-conducting, a hardening phenomenon occurs partially before sand can be sufficiently covered, resulting in poor water flow (poor hot water flow). As a result, the strength of the molded product was extremely low compared to novolac-hexamine, and it was not put to practical use.

Furthermore, by shaping a molten mixture of a solid resol-type phenolic resin (hereinafter referred to as solid resol) using a combined catalyst of an amine catalyst and an inorganic alkali catalyst, novolac, and a lubricant into a special shape, the resin can be made into a special shape. The curing speed, caking resistance and strength of the shell mold could be improved. This has already been disclosed in Japanese Patent Application No. 53-61634.

As a result of further studies by the present inventors, it was found that by incorporating a silane coupling agent and an amide with a molecular weight of less than 500, the properties of the material can be further improved. In particular, it has been found that by coexisting an amide with a molecular weight of less than 500 with a silane coupling agent, the strength of the shell mold can be significantly improved.

The purpose of the present invention is to make the binder used in the dry hot coating method easy to manufacture, have no caking property, be easily fed with an automatic needle, and have high reactivity with little powdering phenomenon. The purpose of this invention is to be able to stably supply a shaped binder at a low cost.

Another object of the present invention is to provide resin-coated sand that has good strength and quick hardening properties due to hot water flowability, and that contributes to preventing gas defects and improving the environment.

The main components of this application are a solid resol type phenolic resin using a combined catalyst of an amine catalyst and an inorganic alkali catalyst, a solid novolac type phenol resin, a lubricant, a silane coupling agent, an amide with a molecular weight of less than 500, etc., and these are mixed. Melted, diameter 0.5~7%, length 05~30~
This is a phenolic resin binder for dry hot coating, which is characterized by being solidified into a bead-like or rod-like shape.

The solid resol, which is one component of the present invention, is produced by reacting 1 mole or more of formaldehyde with 1 mole of phenol in the presence of an amine catalyst and an inorganic alkali catalyst. As the phenol, phenol, ortho-cresol, metacresol, vala-cresol, xylenol, etc. are used. As the formaldehyde, in addition to formalin, there are used formaldehyde, trioxane, etc., which are substantial sources of formaldehyde generation.

Amine-based catalysts are ammonia and amine compounds. As the amine compound, monomethylamine, triethylamine, ethanolamine, aniline, etc. are used.

As the inorganic alkali catalyst, hydroxides or oxides of alkali metals such as sodium, potassium, and lithium, and hydroxides or oxides of alkaline earth metals such as barium, calcium, and magnesium are used.

Novolak, one of the components of the present invention, uses the aforementioned phenol and formaldehyde, and uses oxalic acid and formaldehyde as catalysts.
The reaction is carried out using an organic or inorganic acid such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, or zinc acetate.

In addition to the commonly referred to novolacs, hyoron novolacs also fall within the scope of the novolacs of the present invention.

The amount of novolak used is preferably 50 parts by weight or less per 100 parts by weight of the solid resol, and can be increased to about 80 parts by weight when hexamethylenetetramine (hereinafter referred to as hexamine) is used as a curing accelerator.

The solid resols and novolaks described above can also be appropriately modified with raw materials that react with formaldehyde, such as resosilquine, aniline, urea, melamine, cashew nut shell oil, bisphenol A1 xylene resin, and epoxy resin.

The lubricant which is another component of the present invention includes carnauba wax, montan wax, paraffin wax, polyethylene wax, fatty acid amide (ethylene bisstearamide, methylene bisstearamide, oxystearamide, stearamide, Linoleic acid amide, etc.), fatty acid salts (calcium stearate, etc.), rosin, pinzole resin, polyethylene glycol, polystyrene, talc, etc. are used. Preferably, melting point 1 (
) Fatty acid amide and polyethylene wax at temperatures above 0°C. The amount of these lubricants added is preferably 0.5 to 1 part by weight per 100 parts by weight of the mixture of solid resol and novolac.
It is 0 parts by weight.

The silane coupling agent, which is one of the components of the present invention, is an organosilicon compound that has two or more different reactive groups in one molecule, and one of the reactive groups is a methoxy group or an ethoxy group that chemically bonds with inorganic substances. or a reactive group such as a silanol group.
One reactive group is a reactive group such as a vinyl group, an epoxy group, an amine group, a methacrylic group, a mercapto group, etc., which chemically bonds with an organic substance. By having these reactive groups, the chemical bond between the phenol resin, which is an organic substance, and the silica sand, which is an inorganic substance, is enhanced, and the strength of the shell mold is improved.

Examples of the silane coupling agent of the present invention include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-aminoethylaminopropyltrimethoxysilane, N-β(aminoethyl)γ-72nopropylene Aminosilanes such as viltrimethoxysilane, r-
These include epoxysilanes such as glycidoxypropyltrimethoxysilane and vinylsilanes such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane. One or more of these silane coupling agents can be used.

Examples of amides of the present invention having a molecular weight of less than 500 include acrylamide, dimethylacrylamide, acetoacetanilide, formamide, dimethylformamide, N-methylbenzamide, N-phenylpropionamide, methylolstearamide, N-phenylacetamide,
These include dimethylacetamide, acetamide, stearyl anetho, and propionamide. One of these amides
More than one species can be used.

The amount of silane coupling agent and amide with a molecular weight of less than 500 is 100% of the mixture of solid resol and novolak.
Each part by weight is preferably 0.01 to 10 parts by weight.

The novolak, lubricant, silane coupling agent, and amide having a molecular weight of less than 500 of the present invention are used before reacting the solid resol.
It may be added either during the reaction or after the completion of the reaction.
The lubricant can also be added as a dispersion.

In the present invention, curing accelerators may be used, and these curing accelerators include polyfunctional phenols such as hexane, resorcinol, O-cresol, and bisphenol A, organic acids such as benzoic acid and salicylic acid, calcium hydroxide, and water. These include alkaline earth metals or their salts such as barium oxide and calcium chloride, aniline, phenylene diamine, aminocarboxylic acids, aminocarboxylic acids, and aromatic amines such as aminephenols, among which hexamine is preferred. The blending amount is a mixture of solid resol and novolak 10
0.1 to 15 parts by weight is preferable.

The shaped phenolic resin binder of the present invention has a diameter of 0.5 to
7% and a bead-like or rod-like shape with a length of 0.5 to 30'X. is 1
~5%, rod-like diameter 1-5'X, length 1-15
(The diameter here refers to the smaller side of the cross section and the diameter.)

Note that the bead shape as used in the present invention refers to a hemispherical shape, a rice grain shape, a tablet shape, and the like. The rod shape does not necessarily mean that the cross section is a perfect circle, and may be, for example, square, semicircular, or oval.

Next, the outline of the method for manufacturing the shaped phenolic resin binder of the present invention will be explained.

1 mole of phenol and 1 to 3 moles of formaldehyde are charged into a reaction vessel, and then an amine catalyst and an inorganic alkali catalyst are added. And temperature 50~100°CK
Heat to perform a linear combination reaction for about 30 minutes to 2 hours (5) During this condensation reaction wave or dehydration reaction, novolak, lubricant, silane coupling agent, amide with a molecular weight of less than 500, and if necessary a curing accelerator are added. (It is preferable to add
.

Next, a reaction mixture is obtained by performing a dehydration operation under reduced pressure at a temperature of 100° C. or lower.

This reaction product is extruded and solidified by cooling to obtain a shaped phenolic resin binder.

Another method is to take out the resol containing a lubricant,
After being rapidly cooled and solidified, it is coarsely crushed or pulverized, and on the other hand, the Novo 2, which contains or does not contain a lubricant, is coarsely sanded or pulverized, and the resol and 7 Bor are mixed with a silane coupling agent, an amide with a molecular weight of less than 500, Then, if necessary, a curing accelerator is added and extrusion molding or compression molding is performed to obtain a shaped binder.

Still another method is to take out the reactant from the pot and solidify it without adding a lubricant during the reaction of resol or novolak, and then coarsely crush or grind it, and add a lubricant, a silane coupling agent, and a substance with a molecular weight of less than 500 to the reactant. A shaped binder is obtained by adding an amide and, if necessary, a curing accelerator and extrusion molding or compression molding.

A more detailed explanation of shaping will be added.

There are various types of extrusion granulators used for extrusion molding, and for example, the extrusion pressure of a multi-screw is used to extrude and shape the binder mixture from a die at the tip. This multi-screw extrusion type granulator can be preferably used for shaping in the present invention. The diameter and length of the binder can be freely determined by setting the die hole diameter and shearing speed.

For example, hot cutting produces a more rounded product than cold cutting, and if vibration is applied after hot cutting, the corners can be removed and shaped into beads. The molding temperature during extrusion molding is 90℃ due to the thermosetting resin.
It is important to extrude at temperatures below ℃.

Hereinafter, the present invention will be explained in detail with reference to Examples.

However, the present invention is not limited to this example. In addition, all "parts" and "%" described here indicate "parts by weight" and "% by weight" unless otherwise specified.

Production Example 1゜Phenol 200071. After adding 1380 parts of 37% formalin and then 15 parts of 10% hydrochloric acid, the temperature was raised and the mixture was refluxed for 3 hours at a temperature of 100°C.
The dehydration reaction was carried out under a vacuum of 65c, m145, and the internal temperature was 16
The mixture was taken out of the pot at 0°C and allowed to cool, and then crushed to obtain irregularly shaped granular novolak.

Production example 2゜Phenol 2oooL 37% H/L/2500 parts of marine was charged into a reaction vessel, and then 28% ammonia water 15
After adding 0 parts and 50 parts of 50% sodium hydroxide aqueous solution, the temperature was gradually raised, and after reflux reaction at a temperature of 100'C for 30 minutes, a dehydration reaction was performed under vacuum, and when the internal temperature reached 85°C, it was taken out of the pot and rapidly cooled. did. Then, the solid resol was crushed to obtain irregularly shaped granular solid resol.

Production Example 3 Same method as Production Example 2 except that 50 parts of ethylene bisstearamide, 25 parts of γ-glycidoxyglobyltrimethoxysilane and 38 parts of dimethylformamide (molecular weight 73) were added and mixed and dispersed after the reflux reaction. A solid resol in irregularly shaped granules was obtained.

Example 1゜Reaction MK' 2000 parts of phenol, 37% formalin 2
Then, after adding 150 parts of 28% aqueous ammonia and 50 parts of 50% aqueous sodium hydroxide solution, the temperature was gradually raised, and after the temperature reached 100'IC, after a reflux reaction for 30 minutes, ethylene bisstearic acid was added. Amide 50 parts, r
- 25 parts of glycidoxypropyltrimethoxysilane and 38 parts of dimethylformamide (molecular weight 73) are added, mixed and dispersed, and then subjected to a dehydration reaction under vacuum;
When the internal temperature was 75°C, 330 parts of the novolak from Production Example 1 was gradually added, and the ratio of solid resol to novolak was 100:
It is 15. The proportions of lubricant, silane cutting agent, and amide were 2%, 1%, and 1%, respectively, based on these resins.
When the temperature reaches mso℃, which corresponds to 1.5%, the produced resin is alternately distributed from the reaction vessel into two twin-screw extruders, and extruded from the die at the tip of the extruder 1-1.
The resin was taken out while cooling in air and cut into pieces every 8% of the length.

In this way, a caking agent uniformly shaped into a rod having a diameter of 4% and a length of 8 to 80% was obtained.

Example 2゜Diameter 31X was carried out in the same manner as in Example 1 except that the die was extruded and hot-cut using an extruder with a pore diameter of 3%.

A bead shaped binder with a length of 4% was obtained.

Example 3 350 parts of novolak from Production Example 1, 2150 parts of solid resol from Production Example 2, and 63 parts of ethylene bisstearamide
part, r-glycidoxypropyltrimethoxysilane 13
and stearylamide (molecule t 284 ) 2
This mixture was extruded using a twin-screw extruder with a die hole diameter of 4%, and the resin was taken out while cooling in the air. A rod-shaped caking agent having a diameter of 8 to 10 mm was obtained.

Example 4゜Production Example 10 1000 parts of novolac, 1500 parts of the solid resol of Production Example 2, and ethylene bisstearamide 5
0 parts, 25 parts of vinyltrimethoxysilane, 50 parts of N-methylbenzamide (molecular weight 135), and 100 parts of hexamine, and this mixture was processed using the same extruder method as in Example 3 to form a product with a diameter of 4% and a length of 8%. A rod-shaped caking agent was obtained.

Example 5 Beads with a diameter of 3tX and a length of 4% were made in the same manner as in Example 4, except that they were extruded using a twin-screw extruder with a die hole diameter of 3, and hot-cut and air-cooled while taking off the resin. A shaped binder (rice grain-like) was obtained.

Comparative example 1゜ The amorphous granular binder obtained in Production Example 2 was used.

Comparative example 2゜ The amorphous granular binder obtained in Production Example 3 was used.

Comparative Example 3 350 parts of Production Example 10 Novolak, 2150 parts of the solid resol of Production Example 2, and 63 parts of ethylene bisstearamide were mixed, and this mixture was extruded using a twin-screw extruder with a die hole diameter of 4%, and air-cooled. While doing so, the resin was taken out and cut into pieces every 8% of the length. In this way, diameter 4~, length 8%
A rod-shaped caking agent was obtained.

Comparative Example 4゜350 parts of the lacquer from Production Example 10 and 2150 parts of the solid resol from Production Example 3 were mixed, and this mixture was extruded using a twin-screw extruder with a die hole diameter of 7~ and cut into 40% length pieces. A rod-shaped caking agent having a diameter of 8×1 and a length of 40 mm or more was obtained.

Comparative Example 5 350 parts of the novolak from Production Example 1 and 2150 parts of the solid resol from Production Example 3 were mixed to obtain an amorphous granular binder.

The properties of the binder obtained from the above Examples and Comparative Examples were
Shown in the table.

Table 1 Method for measuring properties of binder Resin caking property: Put binder into a paper bag lined with polyethylene at 15K
A load of 200 Kf was placed at a temperature of 30°C, and the relative solidification properties were compared.

×: Consolidated within 5 days.

○: Condensed into powder after 30 days or more of daily labor: 50% of the inner diameter when the KU-shaped pipe is set in the middle of the piping
Caking agents of different shapes were pumped from the tip of the pipe at a pressure of 2 kg/d, the binding agents were collected at the end, and the pulverization rate was measured.

○: Powdering rate 15% or less ×: Powdering rate 50% or more In order to demonstrate the usefulness of each of the binders obtained in the above Examples or Comparative Examples, resin-coated sand grains were obtained by the following method. Charge the Sanei Shell blended sand heated to 130-140'CK into a Whirl mixer, and add 3% to the sand.
of binder was added, and after mixing for 40 seconds, 1.
After adding 5% cooling water and mixing until the coated sand grains disintegrate, 0.05% calcium stearate was added to the sand, mixed for 20 seconds, and aeration was performed by draining the sand. Resin-coated sand grains were obtained. The properties of the obtained sand grains are shown in Table 2.

The test method for the legibility of sand grains in Table 2 is as follows.

Bending strength (Kmd): According to JACT test method SM-1.

Sticking point (°C): Based on JACT test method C-IK.

Hot tensile strength (Kg/cd): JACT test method 5
According to M-10.

Claims (7)

[Claims] (1) Solid resol-type phenolic resin and solid novolac-type phenolic resin using a combined inhibitor of an Apone catalyst and an inorganic alkali catalyst, a lubricant, a silane coupling agent,
The main components are amides with a molecular weight of less than 500, and these are mixed and melted, and the diameter is 0.5 to 7! %. A phenolic resin binder for dry hot coating, characterized in that it is solidified and shaped into beads or rods having a length of 0.5 to 30 mm. (2) Claim (1) characterized in that the content of the lubricant is 0.5 to 10 parts by weight based on 100 parts by weight of the mixture of solid resol type phenolic resin and solid novolac type phenolic resin. Binding agent as described. (3) The binder according to claim (1) or (2), wherein the lubricant is a fatty acid amide. (4) The binder according to claim (1), wherein the silane coupling agent is one or more of aminosilane, epoxysilane, and vinylsilane. (5) the amide with a molecular weight of less than 500 is acrylamide;
One or more of dimethylacrylamide, acetoacetanilide, formamide, dimethylformamide, N-methylbenzamide, N-phenylpropionamide, methylolstearamide, N-phenylacetamide, dimethylacetamide, acetamide, stearylamide, and glopionamide. The binder according to claim (1), characterized in that: (6) The diameter of the shaped binder is 1 to 5%, and the length is 1 to 15%.
%,
The binder according to item (2), item (3), item (4), or item (5). (7) a curing accelerator in the mixture; Claims (1), (2), (3), and (4), characterized in that they contain hexamethylenetetramine.
The binder according to item (5) or item (6).