JP2556985B2 - Method of manufacturing resin film mold for casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a mold in which foundry sand is filled in a model, and the foundry model is inserted into a microwave heating furnace and irradiated with microwaves to cure the foundry sand. The present invention relates to a method for manufacturing a casting resin model having excellent microwave resistance used in the manufacturing method.

[Conventional technology]

A non-polar resin is applied to the surface of the master model as a material that transmits microwaves and does not generate internal heat to form a resin layer, and this resin layer is released from the master model and cured by heating. There is known a method of manufacturing a model.

As the non-polar resin described above, thermoplastic resins such as polyethylene and fluorine resin, and thermosetting resins such as silicone are known, but polyethylene and fluorine resin have low heat resistance and are easily deformed by heat. However, silicon has the drawback that it is weak in strength and inferior in wear resistance and durability.

Therefore, a reinforcing material mixed with a non-polar epoxy resin with good microwave transparency and an inorganic aggregate such as silica and alumina particles is applied to the surface of the master model, and silicone rubber is applied on top of it and heat cured after release. Then, there is a model manufacturing method in which a surface is reinforced with silicone rubber and a back surface is reinforced with a reinforcing material.

[Problems to be Solved by the Invention]

When casting was modeled by repeatedly using the model manufactured by such a model manufacturing method, the silicone rubber used as the surface layer of the model was damaged during the modeling work due to its weak tear strength, and the binder of the reinforcing material was also used. The non-polar epoxy resin used as a material also becomes brittle under the influence of the heat of the mold during microwave heating, and the model will be damaged.Therefore, when mass-producing the mold by microwave heating, repeat casting with stable quality. I can't model.

That is, the model manufactured by the conventional model manufacturing method has poor durability and is damaged when it is repeatedly used.

Therefore, an object of the present invention is to provide a method for producing a casting resin model which has excellent microwave resistance, abrasion resistance, heat resistance, tear strength, and durability and can be easily manufactured.

[Means for Solving the Problems] On the surface of the master model, a two-component polyurethane resin-forming composition comprising a polyol component and a polyisocyanate component is applied to a predetermined thickness to form a surface layer, and a mold is set. In the method for producing a casting resin model, the backing material is filled in a state where the surface layer is still tacky, and the mold is released from the master model after curing. As a result, the model will have excellent microwave resistance, heat resistance, wear resistance, and tear strength will be increased, and durability will be improved, so that durability during modeling and quality of the mold can be stabilized. be able to.

In the present invention, as the polyol used in the two-component polyurethane resin-forming composition for the surface layer and the binder, those usually used for polyurethane are used. For example, polyether polyol, polyester polyol,
Examples thereof include active hydrogen group-containing polybutadiene, castor oil, and polycarbonate diol. Examples of the polyether polyol include compounds having a structure in which an alkylene oxide is added to an active hydrogen atom-containing polyfunctional compound such as polyhydric alcohol, polyhydric phenol and polycarboxylic acid. As the polyhydric alcohol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6
-Dihydric alcohols such as hexanediol, diethylene glycol, neopentyl glycol and glycerin, trimethylolpropane, pentaerythritol,
Trihydric or higher polyhydric alcohols such as sorbitol and sucrose; polyphenols such as pyrogallol and hydroquinone, as well as bisphenol A
Bisphenols such as; or polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, maleic acid, dimeric acid and other aliphatic polycarboxylic acids, phthalic acid, terephthalic acid, trimetic acid and other aromatic polycarboxylic acids. . Two or more kinds of the above-mentioned active hydrogen atom-containing compounds can be used. Examples of the alkylene oxide added to the active hydrogen atom-containing polyfunctional compound include ethylene oxide, propylene oxide, butylene oxide (tetrahydrofuran), and the like. Alkylene oxide may be used alone or in combination of two or more,
In the latter case, block addition or random addition may be used.
Preferred among these alkylene oxides are tetrahydrofuran, propylene oxide and ethylene oxide.

As the polyester polyol, for example, a condensed polyester polyol or lactone (ε-caprolactone etc.) obtained by reacting a low molecular weight polyol (the above dihydric alcohol, trimethylolpropane, glycerin, etc. with a dicarboxylic acid (the above polycarboxylic acid etc.)) Examples thereof include polyester polyols obtained by ring-opening polymerization.

An active hydrogen group-containing polybutadiene is one that polymerizes butadiene and has an active hydrogen group such as a hydroxyl group, a carboxyl group, and an amine group at the terminal and has about 80% of 1,4 bonds, 1,2
It is possible to use one that can bond by about 90%. Among these, preferred are polyester polyols, polybutadiene containing active hydrogen groups, and castor oil. Of these, hydroxyl groups,
Particularly preferred are polybutadienes having an active hydrogen group having two or more carboxyl groups and castor oil. These may be used as a mixture if necessary.

The OH value is not particularly limited, but is usually 30 to 500, preferably 40 to 4
Fifty.

In the present invention, as the polyisocyanate used for the two-component polyurethane resin-forming composition for the surface layer and the binder, those which can be usually used for polyurethane are used. For example, aromatic polyisocyanates having 6 to 20 carbons (excluding carbons in NCO group) [2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- and / or 4 , 4'-Diphenylmethane diisocyanate (MDI), crude MDI [crude diaminodiphenylmethane {condensation product of formaldehyde and aromatic amine (aniline) or a mixture thereof: diaminodiphenylmethane and a small amount (for example, 5 to 20% by weight) of trifunctional or more Mixture with polyamine} phosgene compound: polyaryl polyisocyanate (PAPI)], etc.]: Aliphatic polyisocyanate having 2 to 18 carbon atoms [hexamethylene diisocyanate, lysine diisocyanate, etc.]: alicyclic polyisocyanate having 4 to 15 oxygen atoms Isocyanates (isophorone diisocyanate, dicyclohexylmethylene diisocyanate, etc.) The number of carbon atoms 8
15 araliphatic polyisocyanates [such as xylylene diisocyanate]: and modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, burette group, uretdione group,
Uretonimine group, isocyanurate group, oxazolidone group-containing modified product) and polyisocyanates other than the above described in Japanese Patent Application No. 59-199160: and mixtures of two or more thereof. Of these, preferred are 2,4- and 2,6-TDI, and mixtures of these isomers, 2,4'- and 4,4'-MDI, and mixtures of these isomers, and these NCO is a modified polyisocyanate containing urethane group, carbodiimide group, allophanate group, urea group, buret group, uretdione group, uretonimine group, isocyanurate group, oxazolidone group derived from polyisocyanate of NCO
% Is usually 15 to 45%, preferably 20 to 35%.

As the thixotropy agent used in the present invention, a surface-treated inorganic filler or synthetic wax which is usually used for urethane is used. Examples of these include colloidal hydrophobic silica, surface-treated calside-type precipitated calcium carbonate, hydrogenated castor oil, and the like. Preferred are surface treated calcite-type precipitated calcium carbonate and hydrogenated castor oil.

As the foam stabilizer used in the present invention, those for soft urethane foam are usually used. For example L-540
(Manufactured by Nippon Unicar Co., Ltd.), SH-190, SRX-294A (manufactured by Tray Silicone Co., Ltd.) and the like.

Known catalysts can be used for the present invention.
Specifically, metal catalysts such as tin-based catalysts [trimethyltin laurate, dimethyltin dilaurate, stannas octoate, etc.], lead-based catalysts [lead oleate, lead 2-ethylhexanoate, lead naphthenate, etc.], other Metal catalysts [metal naphthenates such as cobalt naphthenate];
Amine-based catalysts such as triethylenediamine, tetramethylhexylenediamine, diazabicycloalkenes [DBU (produced by San-Apro Ltd. 1,8-diaza-bicyclo [5,
4,0] undecene-7), etc.]; As examples of trimerization catalysts, metal salts of carboxylic acids, for example, sodium acetate, lead octylate, zinc octylate, cobalt naphthenate, etc .: alkoxides of alkali and alkaline earth metals And phenoxides such as sodium methoxide, sodium phenoxide: tertiary amines such as triethylamine, triethylenediamine, N-methylmorpholine, dimethylaminomethylphenol, pyridine and the like:
Quaternary ammonium bases such as tetraethylammonium hydroxy and the like: imidazoles such as imidazole and 2-ethyl-4-methylimidazole. Of these, preferred is a trimerization catalyst. These may be used in combination of two or more if necessary.

As an additive used if necessary, a filler (wood powder, asbestos, mica, pulp powder, etc.) or a colorant may be added to improve heat resistance and shrinkage.

The NCO index of the two-component polyurethane resin-forming composition of the surface layer used in the present invention is usually 100 or more, preferably 130.
~ 500. Outside of this range, proper wear resistance cannot be obtained.

NCO index of the two-component polyurethane resin-forming composition of the binder used in the present invention is usually 100 or more, preferably
It is more than 300. Outside this range, sufficient heat resistance cannot be obtained.

The curing of the present invention is performed by heating at 100 ° C to 200 ° C. It is preferably 110 ° C to 180 ° C. Heat resistance is low outside this range.

The number of parts of the thixotropic agent used is usually 5 to 200 parts, preferably 10 to 150 parts per 100 parts of polyol.
Outside this range, there is no thixotropy or the workability is poor. The number of used foam stabilizers is 10 polyols
It is 0 to 5 parts, preferably 0 to 3 parts, relative to 0 parts.

The amount of catalyst used is 0.1 to 5 parts, preferably 0.3 to 3 parts, per 100 parts of polyol. Outside this range, an appropriate curing time cannot be obtained.

The amount of additives used as needed is 10
It is usually 0 to 10 parts, preferably 0 to 5 parts, relative to 0 parts.

The coating of the present invention is preferably brushed or sprayed.

〔Example〕

 The first embodiment will be described below.

Specific Example 1 As shown in FIG. 1 (a), a wooden mold, a resin mold, a gypsum mold,
After applying a mold release agent 2, for example, Die-free MS-743 on the surface of the master model 1 such as a mold, a polybutadiene polyurethane resin (mainly Polycure GC-100 100% as a model surface material is used as shown in FIG. 1B). Part, a mixture of 30 parts of curing agent Polycure IS-703. NCO index is about 105) about 2
The surface layer 3 is gel-coated to a thickness of mm.

As shown in FIG. 1 (c), the backup material 5 is set in the mold 4 while the gel-coated surface layer 3 of the polyurethane resin is tacky. As the back-up material 5, 50 parts of sand, 50 parts of foamed alumina, 15 parts of polyurethane resin (3 parts of the main agent Polycure RF-100, 12 parts of the curing agent Polycure IS-703, NCO index 868) were uniformly mixed. .

This was first cured at room temperature, released from the mold as shown in FIG. 1 (d), and then heated at 120 ° C. for 1 hour to be secondly cured to obtain a model.

Example 2 The model surface material in Example 1 was a silicone-based polyurethane resin (100 parts of the main component Polycure GC200 and 29 parts of the curing agent Polycure IS703 were mixed), and the other steps were the same as in Example 1 to produce a model. did.

Example 3 A spray device (APW-5000 Asahi Okuma Sangyo Co., Ltd.) was used as the model surface material in Example 1 with a polybutadiene-based polyurethane resin (100 parts of the main agent Polycure SP and 41 parts of the curing agent Polycure IS703 were mixed). ) About 2mm
Sprayed to a thickness of. A model was manufactured in the same manner as in Example 1 except for the above.

Comparative example Silicon rubber (RTV) is used as the model surface material,
It was manufactured by casting in advance between the master model and the backup material of 2 mm.

As a backup material, 50 parts of sand and 50 of expanded alumina
Part and 15 parts of non-polar epoxy were uniformly mixed and filled in the mold, and cured at 150 ° C. for 4 hours.

When the properties of the model manufactured by each manufacturing method were measured, the results are as shown in the table below.

From the above, it can be seen that the model manufactured by the example according to the present invention is superior in microwave resistance, wear resistance, heat resistance, and tear strength to the model manufactured by the comparative example.

 The second embodiment will be described below.

Specific Example 1 As shown in FIG. 2 (a), a wooden mold, a resin mold, a gypsum mold,
After applying a mold release agent 2, for example, Die-free-MS-743 on the surface of the master model 1 such as a mold, a polybutadiene-based polyurethane resin (main agent Polycure GC-100 is 100% as a surface layer) as shown in FIG. Parts, and 30 parts of curing agent IS-703. NCO index of 105) is gelled and coated with a brush 6 to a thickness of about 2 mm to form a surface layer 3.

As shown in FIG. 2 (c), the backup material 5 is filled with the surface layer 3 of the polyurethane resin, which is set in the mold 4 and surface-coated, also has tack. As the backup material 5, 50 parts silica sand, 50 parts expanded alumina, 6.8 parts polyether polyol (OH number 405), dibutyltin dilaurate
A uniform mixture of 0.034 parts and modified MDI (NCO% 26) 8.2 parts (NCO index 103).

This was primarily cured at room temperature, released from the mold as shown in FIG. 2 (d), and then heated at 120 ° C. for 1 hour to be secondarily cured to obtain a model.

Example 2 The model surface material in Example 1 is a mixture of silicone-based polyurethane resin (100 parts of the main component Polycure GC120 and 72 parts of the curing agent Polycure IS703. NCO index is 10).
5) and a model was manufactured in the same manner as in Example 1 except for the above.

Comparative Example A model was produced in the same manner as in Example 1 except that the model surface material of Example 1 was an epoxy gel coating agent (100 parts of the main component NIDEK 420 was mixed with 11 parts of the curing agent-modified polyamine).

The performance of the thus manufactured model and the sag property when the model surface material was vertically brushed were measured and the results are shown in the following table.

Wear resistance is 1 kg load, 1000 rotations, wear wheel H
-22 taper wear measurement.

From the above, the model 1 and 2 wear amount is as small as 1/3 to 1/6 of the model according to the comparative example, and it has excellent wear resistance, and it is applied to the vertical surface when brushing. Even if it does not lean, the work is easy and the film thickness can be made uniform.

That is, when the thixotropic polyurethane resin is applied by brushing, it can be easily applied by brushing even when applied on a vertical surface, and the thickness of the surface layer 3 can be made uniform.

 The third embodiment will be described below.

In this embodiment, the surface of the master model is coated with a one-component polyurethane resin and then the polyurethane resin is coated by a spray method or a gel coating method to form a surface layer. Thereafter, the model is carried out in the same manner as in the first embodiment. In this way, a model with a bubble-free surface can be obtained.

In other words, the polyurethane resin coated by the spray method or gel coat method is likely to cause foam bite or foam on the surface of the master model due to moisture in the air, etc., and thus the model surface state tends to be bad with bubbles, but If the surface of the model is coated with a one-component polyurethane resin to form a film without bubbles, the surface layer of the polyurethane resin coated by the spray method or gel coat method will adhere to the coated film, and it will be released from the master model. If so, the film without bubbles becomes the film-type surface, so that the film-type surface state becomes good without bubbles.

Specific Example 1 As shown in FIG. 3 (a), die-free MS-743 was applied to the surface of the mass master model 1 as a mold release agent 2 with a brush 7, and a 1-liquid type as a surface coating agent was applied to the surface. A polyurethane resin (Polycure C-100) is applied and dried to form a film 8. See FIG. 3 (ab).

As shown in FIG. 3 (c), 28 parts of polyether polyol (OH value 33) as polyurethane resin, 15 parts of ethylene glycol, 0.5 part of SAG47 (antifoaming agent), and Dabco33LV
1.0 part and 0.05 part of DTD (dibutyltin dilaurate) are uniformly mixed. 100 parts of stock solution Modified MDI (NCO% = 26) 75 parts (NCO index is 108) Airless 2 liquid type spray device 9 (APW-50
00 Asahi Okuma Industry Co., Ltd.), the surface layer 3 of the polyurethane resin is obtained by spray-coating the coating 8 of the master model 1 to a thickness of about 2 mm and curing it.

The two-liquid type spraying device 9 is a device for sending the undiluted solution and the modified MDI in the first and second containers 10 and 11 to a static mixer 13 by a constant amount pump 12, mixing them and jetting them from a nozzle 14, and 15 is added. It is a warming device.

As shown in FIG. 3 (d), the mold 4 is set, and in the state where the surface layer 3 has tack, the back-up material 5 is filled and cured. As backup material 5, 50 parts silica sand, 50 parts expanded alumina, and polyether polyol (OH number 405) 6.8
Parts, DTD 0.0034 parts and modified MDI (NCO% = 26) 8.2 parts (NCO index 103) were added and mixed.

As shown in FIG. 3 (e), the master model 1 is released to form a model.

Example 2 Instead of the polyurethane resin of Example 1, 100 parts of polyether polyol (OH number 405), SAG-47 (antifoaming agent) 0.5
Parts, Dabco33LV 1.0 parts uniformly mixed polyurethane resin (stock solution 106 parts and modified MDI (NCO% 26) 120 parts (NCO index is 10
3)) was coated by a spray method, and otherwise the same as in Example 1 to produce a model.

Comparative Example 1 The surface coating agent in Specific Example 1 was an epoxy gel coating agent (100 parts of NIDEK420, curing agent-modified polyamine 1
A model was manufactured in the same manner as in Example 1 except that 1 part was mixed with the product manufactured by Nippon Devcon Co., Ltd.

Comparative Example 2 A model was produced in the same manner as in Example 1 except that the surface coating agent was not used and SAG-47 (antifoaming agent) in the polyurethane resin was not used.

When the surface condition of each model was measured for wear resistance and hardness, the results are shown in the table below.

Wear resistance is 1 kg load, 1000 rotations, wear wheel H
-22 taper wear test was performed.

 The fourth embodiment will be described below.

In this example, the surface of a master model is gel-coated with a polyurethane resin comprising a polyol, a polyisocyanate, a thixotropy agent, a foam stabilizer and a catalyst to form a surface layer, and a model is manufactured in the same manner as in the second example. It is a thing.

Specific Example 1 As shown in FIG. 2 (a), a wooden mold, a resin mold, a gypsum mold,
100 parts of refined castor oil (OH value 160) as a polyol of the surface layer polyurethane resin as shown in FIG. 2 (b) after applying a mold release agent 2, for example, Die-free MS-743 on the surface of the master model 1 such as a mold. , Modified as polyisocyanate MD
I (NCO% 26) 100 parts (NCO index 217), Calcite-type precipitated calcium carbonate surface-treated as a thixotropic agent (Gelton 50 (manufactured by Shiraishi Calcium Co., Ltd.) 70 parts, as a foam stabilizer (SH-190 (Made by Toray Silicone Co., Ltd.) 1
Parts, 0.05 parts of Polycat 42 (manufactured by San-Apro Co., Ltd.) as a trimerization catalyst, and 2 mm with a brush in a mold with a mold temperature of 60 ° C
Gel-coated to a thickness. 1 hour and 30 minutes later, "Polycure
RF-100 ”3 parts, modified MDI“ Polycure IS-70 ”
A mixture of 12 parts of 3 "(NCO index 868) is applied to the surface layer 3, the mold 4 is set and the backup agent 5 is filled as shown in FIG. 2 (c).

As backup agent 5, 75 parts of sand, 25 of expanded alumina
Section, "Polycure RF-100" 3 sections, "Polycure IS
A mixture of 12 parts of "-703" (NCO index 868) was used. This was secondarily cured at 150 ° C. for 2 hours to form a model.

Example 2 A model was produced in the same manner as in Example 1 except that the number of polyisocyanates used in the polyurethane resin used for the surface layer was 150 parts (NCO index 326).

Specific Example 3 In Specific Example 1 except that 50 parts of surface-treated hydrogenated castor oil (Kusumoto Kasei Co., Ltd.) was used in place of the surface-treated calcite-type precipitated calcium carbonate used for the surface layer in Specific Example 1. I made a model in the same way. However, Disparon 41
10 was dissolved in red bean refined castor oil.

The surface materials and backup materials of the above examples were measured and the results are shown in the table below. The measuring method is based on the method already described.

A liquid coating mold was attached to the model manufactured by the above specific example, the molding sand was filled, and the model was inserted into a microwave heating furnace and irradiated with microwaves to cure the molding sand. The results are shown in the table below.

[Effects of the Invention] Since the two-component polyurethane resin-forming composition comprising the polyol component and the polyisocyanate component was applied to the surface of the master model to a predetermined thickness to form the surface layer 3, the resistance of the surface layer 3 was improved. Excellent microwave resistance, heat resistance,
Since abrasion resistance and tear strength become strong, even if the mold manufactured by repeatedly using the model manufactured by the manufacturing method of the present invention is used, the model is not damaged, and the durability at the time of molding becomes excellent. At the same time, a model that can stabilize the quality of the mold can be easily manufactured.

In addition, since the two-component polyurethane resin forming composition has a low viscosity, it can be easily applied to the surface of the master model.

[Brief description of drawings]

1 (a), (b), (c), (d), 2 (a), (b), (c), (d), 3 (a),
(B), (c), (d), (e) is explanatory drawing which shows the 1st, 2nd, 3rd Example of this invention in order of a process. 1 is a master model, 3 is a surface layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Setoyama 52-1203 Kusuhahanaen-cho, Hirakata-shi, Osaka (72) Inventor Shoji Kiguchi 1-402 Fujisakanishi-cho, Hirakata-shi, Osaka (56) References JP-A-64-40137 (JP, A) Actually-developed Sho-56-60554 (JP, U) JP-B-36-10056 (JP, B2)

Claims (9)

(57) [Claims] 1. A two-component polyurethane resin-forming composition comprising a polyol component and a polyisocyanate component is applied to the surface of a master model to a predetermined thickness to form a surface layer, and a mold is set on the surface layer. The method for producing a casting resin model is characterized in that the backing material is filled in a state where there is still tack, and the mold is released from the master model after curing. 2. A one-component polyurethane resin is applied to the surface of a master model to form a film, and a two-component polyurethane resin-forming composition comprising a polyol component and a polyisocyanate component is formed on the surface of the master model to a predetermined thickness. To form a surface layer, set the formwork and fill the backing material,
A method for producing a casting resin model, characterized in that it is released from the master model after curing. 3. The method for producing a casting resin model according to claim 1 or 2, wherein the polyol component comprises at least one selected from polyester polyol, active hydrogen group-containing polybutadiene and castor oil. 4. The two-component polyurethane resin-forming composition further contains a thixotropic agent, a foam stabilizer, a catalyst and, if necessary, other additives, according to any one of claims 1 to 3. The method for producing a casting resin model according to the item 1. 5. The method for producing a casting resin model according to claim 4, wherein the catalyst is a trimerization catalyst. 6. The method for producing a casting resin model according to claim 4, wherein the thixotropic agent is a surface-treated inorganic filler or synthetic wax. 7. A polyurethane resin-forming composition comprising a polyol component and a polyisocyanate component is used as a binder for a backing material.
Item 7. A method for producing a casting resin model according to any one of Items 6 to 6. 8. The binder contains a trimerization catalyst,
The method for producing a casting resin model according to claim 7, wherein the polyol and the polyisocyanate are contained in a ratio giving an NCO index of 300 or more. 9. The method for producing a casting resin model according to any one of claims 1 to 8, wherein curing is performed by heating at 100 ° C to 200 ° C.