JPH09123293A - Melamine resin molding and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a melamine resin molding having gloss and hardness similar to ceramic whiteware and being used for a water tank for a water closet in which light weight is satisfied by forming a preliminarily molded form of an open cell body and the melamine resin solution, heating and pressurizing the preliminarily molded form. SOLUTION: A preliminarily molded form 6 is formed by three-dimensionally cutting open cell bodies into simple shapes in which a product is developed and performing deaeration while sandwiching the cut open cell bodies 1 between rolls 2 and drawing them and impregnating the open cell bodies with the melamine solution while moving them on a guide plate 5 in an impregnation tank 3 filled with the melamine solution 4. Further, the solution which passes through an overflow pipe 7 from the impregnation tank 3 and flows down into a spare tank 8 is circulated to the impregnation tank 3 through a pump P. The obtained preliminarily molded form 6 is passed through a drying oven of 70-80 deg.C. The dried preliminarily molded form 6 is set in a mold 9 and heated at 150-170 deg.C at 14.7-19.6MPa (150-200kg/cm<2> ) and pressurized in a cavity mold 10. A large- sized complex melamine resin molding is molded without badly influencing productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melamine resin molded product having a complicated and large shape such as a water tank for a toilet, a counter with a washbasin, and a bath tub, and having gloss and hardness similar to that of ceramics, and The manufacturing method is related.

[0002]

2. Description of the Related Art Water tanks for toilet bowls, washbasins, etc. are often made of inorganic materials such as ceramics and enamel, which have excellent water resistance, weather resistance, chemical resistance, etc. so that they can withstand long-term use. Are also made of resin such as fiber reinforced resin (FRP) and artificial marble. Further, in the case of a bath water tank, it is made of stainless steel such as SUS, enamel, FRP, artificial marble, natural wood and the like.

In the case of making a complicated and large shaped product, ceramics are cracked or cracked due to the occurrence of cracks due to the delay of the drying speed due to the difference in the thickness and shape of each part during drying or the difference in the shrinkage amount during firing. Not only the yield is deteriorated due to deformation and the like, but also the dimensional accuracy is poor, so there is a problem in terms of compatibility with buildings. Furthermore, the specific gravity is 2.
Since it is a relatively large material of 2 to 2.4 and is extremely brittle, the thickness must be increased in order to prevent damage due to dropping of objects during use, which makes it even heavier. Is a bottleneck during production, transportation, and construction.

[0004] Next, there are a steel plate enamel and a casting enamel in the enamel.
The specific gravity is as large as about 7.9, and in the case of steel plate enamel, the thickness is 1
It is relatively light because it is as thin as ~ 2mm, but chipping is likely to occur when a sharp-edged object falls, and corrosion occurs from the pinhole on the entire surface of the holo, causing problems such as reduced durability. In case of, thickness 10
Since it is as thick as 15 mm, chipping is unlikely to occur and the effect of corrosion due to pinholes etc. on the entire surface of the holo is small, but it is very heavy because it is a casting, 250 ~
It can reach 400 kg. In addition, it is not only expensive because it is necessary to make sand molds and styrofoam scraps every time, but also the steel plate enamel and the casting enamel have rough surfaces, which not only reduces the appearance but also reduces the commercial value. There is also a problem of environmental deterioration due to heat and dust during production.

Further, in the case of SUS, since SUS is less stretchable than a steel sheet, it is difficult to perform drawing work when it is complicated or has a small cross-sectional area. It takes time and effort to manufacture because it is processed by welding etc., and these products not only wrinkle at the time of drawing work, corrosion from the welded part but also cool due to the metallic color. It has drawbacks such as feeling.

Therefore, as an alternative to the ceramics, enamel or SUS products, resin products have been developed, some of which are made of FRP.

FRP products are molded by press molding, hand lay-up molding, etc.
A so-called polyester resin or the like, which is called a so-called polyester resin, is kneaded with an inorganic filler such as glass fiber, calcium carbonate, aluminum hydroxide or magnesium hydroxide, and a sheet-shaped or bulk-shaped material is heated and pressure-molded.

In the hand lay-up molding, a wooden mold having a shape reverse to that of the product is prepared, a mold release agent is applied, a gel coat is applied and cured, and then glass fibers are laminated with a polyester resin and cured to remove the mold. The master mold with the same shape as the product is manufactured by molding. In the same process as making a master mold from a wooden mold, a use mold having a shape opposite to the product shape is made, and a product is manufactured from the use mold by the same method. The life of this usage type is 150
It is about 200 times, and it corresponds by increasing the number of molds used during mass production. Needless to say, each time the service life of the service mold expires, the service mold must be manufactured from the master one. The manufactured FRP product has a specific gravity of 1.2.
Approximately 1.7, it is relatively light and has high specific strength (strength / specific gravity). However, the surface hardness is as low as about 3H in terms of pencil hardness and is easily scratched, and the gel coat layer provided for improving the surface appearance or chemical resistance has defects such as cracks.

By the way, as a resin product, it is similar to the texture of ceramics, has a light specific gravity of 1.4 to 1.5, is excellent in chemical resistance, weather resistance, cigarette resistance, etc., is hard to break, and particularly exhibits a pencil hardness of 9H or more. There is one using a melamine resin, and there are two types of molding methods of this melamine resin, injection molding and compression molding.

In the injection molding, the melamine resin powder, granules, or a mixture thereof is put into the hopper 1 of the injection molding machine, and is heated by a heater attached to the outside during kneading with a part of the screw and at the time of kneading. It is fluidized by frictional heat, press-fitted through the gate opening of the mold, and melamine and formalin are reactively cured in the mold to be molded.

In the case of the compression molding, a melamine resin and a reinforcing fiber such as cellulose, a catalyst, a cross-linking agent, a filler, a pigment and the like are kneaded in advance, and dried and pulverized to form a fine powder raw material into a tablet by a tablet machine. Then
For the purpose of removing residual water and improving productivity, a tablet preheated by electromagnetic waves etc. is supplied into the mold and heated or pressed to mold it, or the kneaded, dried and crushed fine powder raw material is the final product. It is placed in a container having a shape close to the shape, preheated by electromagnetic waves or the like to be shaped like a rice cake, put into a mold, and heated and pressure-molded in the same manner as the tablet method.

[0012]

However, in the conventional method for molding a melamine resin, heat is applied in the process of mixing cellulose with the initial condensate of melamine, drying and crushing, polymerization proceeds, and it is set in a press mold. When heated and pressurized,
Since the flow time has already become short, the initial flowability is poor, and the condensation reaction between melamine and formalin causes a high molecular weight in a short time, so that the melamine resin is hardened before it reaches the mold. Since it is completed, it is very difficult to form a complicated and large shaped product with a large rise.

Therefore, in the injection molding, the melamine resin is not suitable for large-sized molding because the curing speed of the melamine resin is high and the fluidity of the resin is not good, and the melamine resin is not suitable for molding of gates, spools,
It is necessary to increase the runner and the like, and in the case of a thermoplastic resin, there is no problem if the spool and a part of the runner are kept warm, but in the case of a melamine thermosetting resin, all of them are lost, resulting in a significant cost increase.

Further, although compression molding allows molding of a relatively large product, it is difficult to mold a product having a large rise, and this tendency is remarkable when glazing for coating the surface with a single layer of melamine resin is applied. Becomes

Therefore, the present invention uses a melamine resin and has a luster, hardness, etc. similar to those of ceramics, and satisfies the weight reduction requirements. A manufacturing method is provided.

[0016]

Means for Solving the Problems The present invention forms a preform from a continuous pore body and a melamine resin solution, and heats and pressurizes the preform to mold and cure the preform to obtain melamine. A resin molded product is manufactured.

As the method for producing the melamine resin molded product of the present invention, a main body of a preformed product obtained by three-dimensionally cutting continuous pores according to a product shape is set in a porous mold, and a negative pressure is applied from the inside of the porous mold. And form a preformed body by impregnating the body of the preformed body with a melamine resin solution from the outside of the porous mold, put the preformed body in a mold, and mold the preformed body by heating and pressing, It can also be cured to produce a molded article.

Further, the preform is prepared by spraying the reinforcing fiber and the melamine resin solution on the porous mold, or by spraying the reinforcing fiber and the melamine resin powder on the porous mold and heating them to partially fix them. A molded product may be produced by forming the molded product, putting the preformed product in a mold, and heating and pressurizing the preformed product to cure it. In manufacturing, the porosity of continuous pores is 20 to 95%
And the thickness of the continuous pore body is t ₀ , and the desired thickness of the product is tp
Then, it is preferable that t ₀ ≧ tp / 0.2 to 0.4.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the melamine resin, for example, a melamine-based resin such as methylated melamine or butylated melamine is used, and an alkaline component such as ammonia is added to melamine and formalin, and a solvent such as water or alcohol is used. Alternatively, a solution of the precondensate dissolved in the mixture is prepared.

On the other hand, as the open-pore body, a foam of resin having open cells such as urethane and vinyl chloride, or glass fiber, non-woven fabric, felt or paper dissolved in caustic soda solution is preformed by pressing or the like. A porous material made of fibrous material such as a substance is used.

FIG. 1 is an explanatory view of one embodiment of a manufacturing method according to the present invention, in which a continuous pore body is three-dimensionally cut into a substantially developed product, and the cut continuous pore body 1 is sandwiched between rolls 2 and air is drawn. And the continuous pore body is impregnated with the melamine solution while moving on the guide plate 5 in the impregnation tank 3 filled with the melamine solution 4 to form the preform 6. In addition, the auxiliary tank 8 is passed from the impregnation tank 3 through the overflow pipe 7.
The solution that has flowed down to is circulated to the impregnation tank 3 by the pump P. In addition, as another method for forming a preformed body, a solution prepared by dissolving paper in a caustic soda solution in advance is poured into a mold through which a porous material such as a wire net is placed on the surface, and the preformed product is dried by a press or the like. The porous material thus obtained is impregnated with the solution by means of vacuum, a pressure impregnation device, or the like.

The preform 6 thus obtained is passed through a drying oven at 70 to 80 ° C., and the dried product is set in a mold 9 and
50 to 170 ° C, 14.7 to 19.6 MPa (15
Heating at 0-200 Kg / cm ² ), cavity type 10
It is possible to mold a complicated and large melamine resin molded product by pressurizing the product without impeding productivity.

The melamine solution used is a solvent such as water 10
The weight ratio is about 80-90 with respect to 0, and it is halved when dried. Therefore, the quality and properties of the product are the porosity and thickness of the foam such as urethane and the fibrous porous material such as felt that become the impregnation base material. Will be greatly related. That is, when the porosity is low or the thickness is thin, the amount of melamine impregnated decreases, the surface properties are poor when heated and pressure-molded, and only the properties similar to those of the impregnated base material are obtained from the viewpoint of physical properties. Therefore, the porosity of the impregnated substrate is 20 to 95%, preferably 50 to 90%, and the impregnated amount of melamine at that time is 0.44.
× 0.5 to 0.47 × 0.9 = 0.2 to 0.4, where t ₀ ≧ t _p /0..0, where t _{p is} the desired thickness of the product and t ₀ is the thickness of the impregnated base material. It is necessary to set the thickness of the impregnated base material to be 2 to 0.4. However, in actual production, since there is an amount of protrusion as burrs, it is desirable to use about twice the value, and t ₀ ≧ 2 × t _p /0.2-
It is sufficient to apply the formula of 0.4.

In molding a complicated and large melamine resin molded product, it is important that the impregnated base material is well matched to the product shape at the time of heating and pressure molding, and a soft and extensible material is suitable. 100% elongation
As described above, it is preferably 150 to 300%, and since the product is often colored, it is desirable to use a product that is as white as possible. Furthermore, since a heat of 150 to 170 ° C. is applied during molding for a short time of about 20 to 70 seconds, an impregnated base material having a heat resistance of 150 ° C. or higher is selected as the impregnated base material. There is a need.

In the present invention, since the melamine is preliminarily spread on the impregnated substrate satisfying the above conditions and set in the mold, the fluidity at the time of initial heating is sufficient only in the thickness direction. That is, the initial condensate impregnated base material of melamine is 1 /
When it is compressed to 5 to 1/10, the initial condensate of melamine contained inside it oozes out, and the surface properties are excellent and the physical properties are similar to those of ordinary melamine products. It is possible to manufacture a complicated and large molded article such as.

FIG. 2 is an explanatory view of another embodiment of the production method of the present invention, which is an open-celled plate-like material of resin such as urethane or vinyl chloride or fibrous material such as cellulose, polyester, nylon, wool, glass or the like. The non-woven fabric, the open-cell body 1 in which the felt is three-dimensionally cut according to the shape of the product is punched into a mold such as an aluminum casting, or a porous mold 11 made by processing a perforated plate such as punching metal or directly Water, alcohol or their initial condensate obtained by reacting melamine and formalin in the presence of alkali while being set through a mesh 12 such as a plastic mesh or a wire mesh and sucking in vacuum from the inside of the porous type. A melamine solution dissolved in a mixed solvent is applied and impregnated by a spraying means such as a sprayer to preform.

The melamine resin to be sprayed is not limited to a solution, and a powdery or granular melamine molding material obtained by mixing a pigment, a filler and the like with an initial condensate of melamine, drying and pulverizing the melamine resin is porous or fibrous. It may be contained in the space.

However, in the case of spraying a powdery or granular molding material, when the suction of the vacuum pump is stopped, the substances adhering to the surface will spill out. Therefore, the condensate solution of melamine or the melamine and the impregnating group concerned. Apply the silane coupling agent solution used as a binder to improve the adhesion with materials, fillers, etc. by a means such as spraying, or partially melt by electromagnetic waves while pulling with a vacuum pump from the inside of the porous type. It is necessary to solidify and immobilize.

The preformed body thus obtained was removed from the porous mold and dried, and then set in a pressing mold for 15 minutes.
Heat to 0 to 170 ° C, 14.7 to 19.6 MPa
(150 to 200 Kg / cm ² ) is pressed for production.

In order to satisfy performances such as appearance and strength, there is a problem of balance between the amounts of melamine resin and impregnating material.
When using the initial condensate of melamine, a solvent such as water 100
On the other hand, since it is a solution having a weight ratio of 80 to 90 and is halved when dried, the porosity of the impregnated base material is 20 to 95%, preferably 50 to 90%. 44 x 0.5 to 0.47 x 0.9 = 0.2 to 0.4
Becomes

Therefore, when the desired thickness of the product is tp and the thickness of the impregnated base material is t ₀ , t ₀ ≧ t _p /0.2 to
The porosity and thickness of the impregnated base material are selected so as to be 0.4. However, in actual production, it is desirable to use about twice as much as there is a protruding portion such as burr.
It may be applied so that ₀ ≧ 2t _p /0.2 to 0.4.

FIG. 3 is an explanatory view of another embodiment of the manufacturing method of the present invention, which is directly or while pulling with a vacuum pump from the inside of the porous type or through a plastic mesh such as polypropylene, polyethylene, nylon or a metal mesh. The melamine condensate solution or the melamine molding powder material and polyester, nylon, the reinforcing fiber obtained while cutting the roving of the glass fiber through a rubber roller provided with a blade for cutting to a required length at the same time. To make a preform in a substantially product shape.

When using a melamine molding powder material,
As in the previous method, it is necessary to apply melamine initial condensate or the like from the surface side of the porous mold, or to heat and immobilize it partially by heating with electromagnetic waves while sucking with a vacuum pump from the inside of the porous mold. There is.

When the melamine condensate solution is used, the porosity and thickness of the impregnated base material are t ₀ ≧ 2tp / 0.2.
Although the formula of ~ 0.4 can be applied, when a melamine molding powder material is used, t ₀ ≧ because it is determined by the porosity of the impregnated base material.
2t _p /0.50 to 0.90 (however, 0.50 to 0.9
0 is a formula of porosity of impregnated substrate).

Also in this embodiment, the melamine precondensate or the powdery melamine molding material is preliminarily molded in a state of being spread flat on the impregnated base material, which is set in a press mold and heated and pressed. The flow range during initial heating is mainly in the thickness direction. That is, 1/5 to 1/10 of the impregnated base material containing the melamine initial condensate or the powdery melamine molding material is used.
When compressed to, the melamine contained in the cells of the porous body oozes out, and then the condensation reaction with formalin causes the melamine to have a high molecular weight and hardens.

Thus, it is possible to easily form a complicated and large product such as a water tank for a toilet bowl, a counter with a washbasin, etc., which has a good surface condition and is not much different from ordinary melamine in physical properties.

[0037]

【Example】

Example 1 Formalin and aqueous ammonia were added to melamine and the mixture was mixed at 90 ° C. for 4 minutes.
The reaction was carried out for 0 minutes to prepare a water / alcohol mixed solution (solid content: 45%) of the melamine initial condensation product.

Next, in the impregnation tank shown in FIG. 1, a continuous foam body obtained by three-dimensionally cutting 1400 mm × 700 mm of ester urethane having a porosity of 80%, an elongation of 200% and a thickness of 20 mm was fed with a gap of 5 mm. After being inserted into a roll portion and being degassed by passing between rolls, the melamine initial condensate solution was impregnated. This was placed on a punching tray made of aluminum that had been processed into a substantially product shape, and the product that had been acclimated to the shape was dried in a convection drying chamber at 80 ° C. for 2 hours.

Subsequently, this preform was set in a press-molding die, and 19.6 MPa (200 Kg / c).
m ² ), heat at 165 ° C for about 35 seconds, pressurize,
1300 mm x 600 with a 0 mm height facing part, a 125 mm apron part, and a washbasin part depth of 190 mm
A counter with a washbasin integrated type of mm × 190 mm was produced. The product thickness at this time was about 3 mm.

Example 2 Appearance of a product A silk screen was applied to the inner surface of an aluminum punching plate processed into a U shape, and this was dipped in a caustic soda solution of Japanese paper, and the thickness of the Japanese paper was about Imm. Was produced. 2 in a convection drying chamber at 80 ° C
After drying for an hour, impregnate the melamine initial condensate solution,
Five sheets are piled up and set in a press die, and 19.6 MPa
(200 Kg / cm ² ), heating at 16.5 ° C. for 25 seconds,
Pressurized to a thickness of approximately 2 mm, 525 mm x 235 mm x 2
A pedestal which is a 50 mm approximately U-shaped washbasin piping cover was produced.

Example 3 An aluminum punching plate having a thickness of 3 mm and a pitch of 10 mm and a thickness of 3 mm was sheet-metal-welded, and had a water repelling part with a wall mounting surface height of 50 mm, with a major radius of 580 mm and a minor radius of 380 mm at approximately the center. 13 with a 195 mm deep washbasin
After making a preforming mold of a counter with a washbasin of 00 mm x 600 mm x 3 mm and applying a wax-based mold release agent,
FRP having an airless tank, a pair of rolls with a cutting blade on one roll, and a nozzle for spraying a liquid
Using a spray-up molding machine, while sucking with a vacuum pump from the back side of the preforming mold, water and alcohol solution of melamine condensate and nylon roving were cut to a length of 12.5 mm on the surface of the mold. Were simultaneously sprayed to a thickness of 7 mm.

This was dried together with the mold at 60 ° C. for 2 hours to prepare a preform. Next, this preform was set in a pressing die and set at 165 ° C. and 19.6 MPa (200
Kgf / cm ² ) was heated for 40 seconds, pressed and molded to obtain a product having a thickness of 3 mm.

EXAMPLE 4 A 20 mm-thick plate of ester soft urethane having a porosity of 80% and an elongation of 200% was three-dimensionally cut according to the shape of the counter with a washbasin of Example 3. -Cover the surface of the preforming mold of No. 3 and apply a powdered melamine molding material with cellulose fibers and pigments to the surface of the mold while sucking from the back of the mold with a vacuum pump using a gun for powder spraying After being contained in the pores of the material, water and alcohol solution of the melamine initial condensation product are applied from the surface to immobilize the powdery melamine molding material adhered to the surface.

This was dried together with the mold at 60 ° C. for 2 hours to prepare a preform. Next, this preform was heated and pressed for 40 seconds under the same conditions as in Example 3 to obtain a product. Comparative Example Pulp was added to the initial condensate of melamine, the mixture was dried at 80 ° C. for 2 hours and crushed, and a tablet of a general molding material in which a pigment was added thereto was set in a press mold,
The basin-integrated counter of Example 1 was manufactured by heating and pressurizing at 165 ° C. for 25 seconds at 19.6 MPa (200 Kg / cm ² ).

Table 1 shows the results of the test. Although the examples of the present invention are slightly inferior to the comparative examples in bending strength, they are excellent in impact resistance and light in weight.

[0046]

[Table 1]

[0047]

The effects of the present invention are as follows.

(1) It is possible to produce a complicated and large melamine resin molded product which is excellent in impact resistance and is lightweight, without impairing productivity.

(2) Water tank for toilet bowl, which is made of a light and hard-to-crack melamine resin molding similar to the appearance of ceramics.
A counter with a washbasin can be easily produced.

(3) The apparatus is simple and inexpensive because it is flat and impregnated with the melamine solution.

(4) If the inside of the continuous porous body is clogged, the degree of vacuum increases, and this can be detected to control the impregnation amount.

(5) The strength of the melamine resin product can be easily changed by controlling the amount of reinforcing fibers, and the increase in the amount of melamine and reinforcing fibers attached changes the degree of internal vacuum, making it easy to control the thickness. it can.

(6) Since the resin solid content is higher than that of the solution, the thickness of the preform may be small, so that the preforming time is shortened and the heating method is used to maintain the shape of the preform. For example, drying is not necessary, and when using a liquid binder, the time can be shortened.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of a manufacturing method according to the present invention.

FIG. 2 is an explanatory view of another embodiment of the manufacturing method according to the present invention.

FIG. 3 is an explanatory view of still another embodiment of the manufacturing method according to the present invention.

[Explanation of symbols]

1 cut continuous pore body, 2 rolls, 3 impregnation tank, 4 melamine solution, 5 guide plate, 6 preformed body, 7 overflow tube, 8 preliminary tank, 9 mold, 10 cavity type, 11 porous type, 12
Mesh

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 31:44

Claims (7)

[Claims] 1. A melamine resin molded product, characterized in that a preformed product is formed from continuous pores and a melamine resin solution, and the preformed product is molded and cured by heating and pressing the preformed product. 2. A melamine resin molded product, characterized by forming a preformed product from continuous pores and a melamine resin solution, and heating and pressing the preformed product to mold and cure the preformed product. Method. 3. A preformed body is formed by preforming a continuous pore body and impregnating the continuous pore body with a melamine resin solution. The preform body is placed in a mold and heated and pressed to form the preform body. Molding and hardening are carried out, The manufacturing method of the melamine resin molding of Claim 2 characterized by the above-mentioned. 4. A continuous pore body, which is cut into three dimensions according to the shape of a product, is set in a porous type, a negative pressure is applied from the inside of the porous type, and the continuous pore body is impregnated with a melamine resin solution from the outside of the porous type. The method for producing a melamine resin molded product according to claim 2, wherein the preformed product is formed by allowing the preformed product to be placed in a mold, and the preformed product is molded and cured by heating and pressing. 5. A preform is formed by spraying reinforcing fibers and a melamine resin solution onto a porous mold, and the preform is placed in a mold and heated and pressed to mold and cure the preform. The method for producing a melamine resin molded article according to claim 2, 6. A preform is formed by spraying reinforcing fibers and melamine resin powder onto a porous mold and heating it to partially fix the preform, and putting the preform into the mold.
The method for producing a melamine resin molded product according to claim 2, wherein the preformed product is molded and cured by heating and pressing. 7. The porosity of the continuous pore body is set to 20 to 95%, and t ₀ ≧ tp / 0.2 to 0.4 (where t ₀ is the thickness of the continuous pore body, and tp is the desired thickness of the product). The method for producing a melamine resin molded article according to claim 2, wherein