JP2003191257A - Colored melamine foam and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colored melamine foam made to have a desired density and colored homogeneously and a method of manufacturing the same, by mixing a required coloring material in the material of a melamine foam, by injecting this material into a required molding tool with the quantity thereof controlled intentionally and by foaming it under volumetric restriction. <P>SOLUTION: The colored melamine foam having an external contour shape conforming with the internal contour shape of the required molding tool 12 and also constituted of a three-dimensional netlike skeleton being homogeneous and free of nonuniformity of color is obtained by the method wherein the material M of the melamine foam to which the required coloring material 16 is added and which is in the quantity controlled intentionally is injected into the molding tool 12 and by foaming it under the volumetric restriction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored melamine foam and a method for producing the same, and more specifically, it is preferably used as a cleaning material for washing automobiles and the like, and can be commercialized by coloring it in any color. It relates to an enhanced pigmented melamine foam and a method for producing the pigmented melamine foam.

[0002]

2. Description of the Related Art Generally, in the production of a foam made of a melamine resin, formaldehyde and an additive such as a foaming agent, a catalyst and an emulsifier are blended and sufficiently mixed with melamine which is a main raw material to foam into a desired shape. It is carried out by curing after molding.

The color of the melamine foam obtained by the above-mentioned production method is limited to white, and it has never been colored. Generally, as a means for coloring a foam, a method of kneading a required pigment into a raw material resin of the foam and foaming is known, but a thermosetting resin such as a melamine / formaldehyde resin is not heated and melted. However, the pigment could not be kneaded and contained.

Further, Japanese Patent Application Laid-Open No. Hei 1 (1999), filed earlier by the applicant of the present application.
Even in the "wiping cleaner" according to JP-A 1-128137, only a white cleaner can be produced, and a surfactant having a detergent action oozes out from the inside during use to show good detergency, while It was not possible to create various shades by incorporating fashion trends, etc., and it was not possible to increase the product strength of that point.

In order to solve such a problem relating to coloring, in the "dyeing method of a melamine resin foam" described in JP-A No. 2001-2790, the melamine foam is used as a disperse dye or an acid dye under the necessary conditions. There is proposed a method of coloring by dyeing with the dye by immersing and heating in.

In the case of the "method for dyeing a melamine resin foam" described in JP-A 2001-2790, the pH is
The melamine foam is immersed in an acidic aqueous solution of 3.0 to 6.5 and heated or boiled to dye, that is, fix the pigment. However, melamine foam is generally prone to hydrolysis under acidic conditions, and the hydrolysis is also promoted by heating, and as a result, the foam cannot maintain its shape, that is, it collapses. There are inherent problems.

In the manufacturing process, at least two steps are required: a step of soaking the melamine foam in a predetermined dye or the like for heating and dyeing, and a post-processing step of washing and drying the used dye or the like with water. It is also pointed out that it becomes necessary to carry out continuous work and the manufacturing cost increases.

In contrast to the method for dyeing a melamine foam as described above, a coloring material expressing a predetermined color is directly mixed in the raw material of the melamine foam, and the mixture is subjected to microwave irradiation or the like to form a slab foam. Then, the foamed body may be obtained by cutting it into a desired shape and the like. In the case of this method, since the color is mixed by mixing the coloring material into the foam raw material, the foam is not given an unnecessary atmospheric load or the manufacturing cost is not increased as described above.

[0009]

However, in the case of the above-mentioned slab foaming, the extruded raw material is heated by microwave irradiation, that is, the foaming aid and the water content (boiling point) contained in the raw material of the melamine foam. Since a gas such as a foaming agent generated by vaporization at 100 ° C.) is produced by foaming the melamine foam raw material M to the foaming limit point, the foaming limit point is determined by the generation degree of the gas. .

By the way, the foaming mechanism of the melamine foam raw material is considered as follows. That is, the foaming aid such as hydrofluoroether (boiling point 60 ° C.) in the melamine foam raw material and water (boiling point 100 ° C.) which acts as a foaming agent and a solvent start vaporization by microwave irradiation. The gas generated by the vaporization expands (foams) the melamine foam raw material from the inside. As the expansion proceeds, the temperature inside the melamine foam raw material also sequentially rises, whereby the condensation reaction of the methylolmelamine resin is started. From the stage where the blowing agent such as the hydrofluoroether having a low boiling point is completely gasified, the curing reaction of the skeleton formed by the conventional foaming starts to proceed with the expansion of the vaporized water. The curing reaction of the skeleton progresses with the foaming due to the gasification of water, and finally the gasification of the water ends, and the curing reaction reaches the end point, and the cell film formed between the skeletons vaporizes. It is destroyed by a foaming agent. The disappearance of the evaporant initiates a further increase in temperature and cure of the resulting framework.

As can be seen from the above-mentioned foaming mechanism of the melamine foam raw material, the size and the like of the obtained skeleton are mainly determined by the amount of gas generated and the like. That is, if the gas generation is uneven, only a part of the foaming proceeds, and the other part has an inhomogeneous skeleton structure in which the foaming is not sufficiently performed. That is, the coloring material mixed with the melamine foam raw material is also non-uniformly distributed, and as a result, color unevenness occurs.

Further, the colored melamine foam obtained by the above-mentioned slab foaming is merely a lump, and it is necessary to cut the melamine foam into a desired shape in order to obtain a final product. However, this results in discarding the excess end after cutting, that is, a material unavoidable loss occurs,
There is concern about the deterioration of manufacturing costs. In addition, there is also a problem that some cutting mistakes affect the shape of other final products and the yield is deteriorated.

Furthermore, since the melamine foam raw material is allowed to foam indefinitely depending on the generation of the gas, even if the density of the melamine foam obtained is large, it is about 30 kg / m ³ , which is practical considering the homogeneity of the structure. The upper limit is about 20 kg / m ³ . In order to avoid the upper limit of the density, it is conceivable to reduce the amount of gas that causes foaming. Specifically, a method of reducing the amount of water, a foaming agent, or the like, which is the generation source of the gas, or a method of reducing the intensity of microwaves for irradiation can be mentioned.

However, when the water content, which is a gas generation source, is reduced, the raw material melamine foam material does not become a good paste-like material, and as a result, it becomes heterogeneous at the raw material stage and If the amount of the foaming agent is reduced, good foaming cannot be achieved, resulting in a melamine foam having coarse cells, that is, a heterogeneous skeletal structure. Further, when the intensity of microwave irradiation is lowered, the foaming itself and the condensation / curing reaction become incomplete, and the melamine foam itself cannot be obtained.

[0015]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned drawbacks inherent in the coloring of the melamine foam according to the prior art, which is preferably solved.
The desired colorant is mixed with the raw material of the melamine foam, the amount of this raw material is intentionally controlled, and the raw material is injected into the required molding die and foamed under the volume limitation to obtain the desired density and homogeneity. It is an object of the present invention to provide a colored melamine foam that has been colored to a color and a method for producing the same.

[0016]

In order to overcome the above-mentioned problems and achieve the intended purpose, the colored melamine foam according to the invention of the present application contains a required coloring material and a purposely controlled amount. By pouring the melamine foam raw material of No. 3 into a required molding die and foaming it under a volume restriction, a melamine resin having an outer contour shape matching the inner contour shape of the molding die and having a uniform and uniform color is obtained. It is characterized by being composed of a three-dimensional net-like skeleton.

In order to overcome the above problems and achieve the intended purpose, a method for producing a colored melamine foam according to another invention of the present application is to prepare a melamine foam raw material to which a required coloring material is added, By pouring the raw material into a required molding die and foaming it under volume limitation, a foam molding having an outer contour shape that matches the inner contour shape of the molding die is obtained. By intentionally controlling the amount of the melamine foam raw material injected into the foam, the density of the foamed molded product obtained is set to a desired value, and a homogeneous three-dimensional reticulated skeleton without color unevenness is foamed. It is characterized in that it is formed inside.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a colored melamine foam and a method for producing the same according to the present invention will be described below with reference to the accompanying drawings with reference to preferred embodiments. The inventor of the present application, when foaming a melamine resin foam (hereinafter, referred to as melamine foam), by mixing a required amount of a coloring material to a raw material forming the melamine foam, the resulting melamine foam raw material By intentionally controlling the amount and injecting it into the required molding die and causing foaming within the molding die while limiting the volume, it has an outer contour shape that matches the inner contour shape of the molding die and is uniform. It was discovered that a colored melamine foam that has achieved coloring can be easily produced.

As shown in FIG. 1, a colored melamine foam 10 according to a preferred embodiment of the present invention is composed of a colored melamine foam obtained by foaming a melamine resin in which a required coloring material 16 is homogeneously added, and is molded as described later. It is obtained by injecting a melamine foam raw material M as a raw material in a controlled amount into the mold 12, and foaming the raw material M under the volume restriction in the molding die 12.

The colored melamine foam 10 is specifically manufactured by a manufacturing apparatus 30 as shown in FIG. The manufacturing apparatus 30 is for foaming a necessary coloring material 16 and a required foaming agent, foaming auxiliary agent, emulsifier, surfactant, pH adjusting agent, pentane, etc. for the main raw material melamine resin raw material. Preparation of raw material to obtain melamine foam raw material M by mixing and kneading required amount of solvent and curing catalyst such as formic acid
A kneading section 32 and the kneaded melamine foam raw material M
Is injected into a molding die 12 having a desired inner contour shape while being weighed, and foamed and cured by microwave irradiation or the like to obtain a colored melamine foam 10 that is uniformly colored. Composed.

As the coloring material 16, any substance such as water-soluble and oil-based materials (dye, pigment, etc.) can be used, and basically, it is homogeneous with the melamine resin raw material. It can be used without any problem as long as it can be mixed with, and its aqueous or oily properties are not a problem. Further, pigment powder such as mica typified by an inorganic system can be used, and high designability and high-class coloring can be achieved. Especially when considering the coloring of the melamine foam, a water-soluble substance is preferable in view of the fact that the melamine foam raw material is water-soluble. Even if it is an oily substance other than this, since the melamine foam raw material can be in an emulsion state,
Its use is possible.

The degree of coloring is determined by the amount of the coloring material 16 added to the melamine resin, which is the main raw material, and this amount of addition is set to a level that does not adversely affect the foaming of the colored melamine foam 10. . It should be noted that when used as a cleaning tool for automobiles, etc., pigments that are powders are not used so as not to scratch the items to be cleaned such as automobiles. It is selected as appropriate.

The raw material adjusting / kneading section 32 is a portion for mixing all the raw materials required for producing the colored melamine foam 10 and further kneading them uniformly to obtain the melamine foam raw material M. Specifically, a single-screw or twin-screw extruder, a kneader, a pressure kneader, a co-kneader, a Banbury mixer, a Henschel mixer, a rotor mixer, a pin mixer, a homogenizer, and other kneaders 34 are preferably used. No special device is required for this kneading, and the kneading speed is not limited. The temperature and time at the time of kneading depend on the physical properties of the above-mentioned objects to be mixed, but it is sufficient that the objects are sufficiently mixed and kneaded. Further, in consideration of handling a liquid substance such as a melamine aqueous solution, a liquid mixing tank 36 may be provided in addition to the kneading machine 34 and the like. The pH adjusting agent has an action of delaying the reaction / curing of the mixture after mixing / kneading. Therefore, the addition amount is appropriately changed depending on the mixing / kneading time here and the time of injection into the molding die 12 described later. To be used.

The pouring / foaming section 40 is used for adjusting the raw material.
The melamine foam raw material M obtained in the kneading section 32 is a portion for obtaining a colored melamine foam 10 as a foamed molded product having an outer contour shape that matches the inner contour shape of the molding die 12, and a plurality of the molding dies 12 are provided. A transfer means 42, such as a belt conveyor, which is arranged in line and transfers the mold 12 by a drive source (not shown), and the transfer means 42.
And a foaming / drying means 44 having a heating mechanism 44a which is disposed in the middle of the transfer path and is capable of foaming / curing / drying the entire mold 12 during transfer by microwave irradiation or the like. Further, when the obtained colored melamine foam 10 is dried, as will be described later, since by-products such as water and toxic formaldehyde are generated during foaming, a discharge device (not shown) for removing them by suction, for example. Is provided. The heating mechanism 44
The type, the number, the arrangement position, and the like of a are appropriately determined according to the size and the like of the material to be foamed.

The mold 12 is basically openable and closable,
In addition, it is composed of two upper and lower halves 12a, 12a that define an inner contour shape that matches the outer contour shape of the colored melamine foam 10 that should be obtained inside when closed, and the required position is foamed at the time of drying described later. A plurality of through holes 12b for discharging moisture and formaldehyde vapor generated as by-products to the outside are provided. This molding die 12
Is smaller than the free rise of the melamine foam raw material M to be injected, that is, the foam volume when the slab is foamed. This is the density (A) of the foam obtained by so-called molding using the required molding die 12.
Is to expand the same amount of foaming material in the open state, that is, to make it larger than the density (B) of the foam that is slab-foamed, and the pack rate = (A) / (B) is 1 or more. Refers to something.

The material of the molding die 12 is appropriately selected according to the heating mechanism 44a of the foaming / drying means 44 described above. For example, when microwave irradiation is adopted as the foaming / drying means 44,
In order to efficiently reach the melamine foam raw material M into which the microwave irradiation is injected, the molding die 1
As the material of 2, a material having a small dielectric loss coefficient such as engineering plastic, ceramics or FRP is preferably adopted.

Further, the shape of the colored melamine foam 10 having a complicated three-dimensional shape is not limited to the simple shape such as the rectangular parallelepiped shape, but if a conventionally known method such as a plurality of split molds is used as the molding die 12. Can be easily manufactured.

The discharge holes 12b do not hinder the foaming of the colored melamine foam 10 due to volume expansion, and the melamine foam raw material M is foamed inside the molding die 12.
Is set to have a sufficiently small size and a predetermined air permeability so as not to leak to the outside of the molding die 12 through the discharge hole 12b. Specifically, it is φ10 mm or less, preferably φ5 mm. It is considered as follows. Further, if necessary, a porous release paper, a ceramic filter, or the like that physically covers the discharge hole 12b while ensuring air permeability and that is easily peeled from the obtained colored melamine foam 10 is also used. By adopting these, the discharge hole 12b can be set large.

Further, as described above, the discharge hole 12b is for discharging the vaporized foaming aid, the foaming agent, the water generated as a by-product at the time of foaming and the vapor of formaldehyde to the outside. This is because, if the generated steam is not properly discharged from the mold 12, the pressure of the steam, that is, the existence of the steam itself greatly hinders the formation of a homogeneous three-dimensional network structure due to foaming. Therefore, the generated steam can be sufficiently discharged, in other words, the pressure inside the molding die 12 is maintained regardless of the amount of the generated steam.
The expansion pressure at the time of foaming should be below.

As a result of examining the above-mentioned reasons, the molding die 1
It was confirmed that the discharge hole 12b having an opening of at least about 0.2% or more with respect to the total surface area of No. 2 was required. Further, if the opening area of the discharge hole 12b is too large, various gases serving as a driving force for foaming the melamine foam raw material M will also be discharged, and therefore it is necessary to set it so as not to hinder the foaming. The discharge hole 12b
The position where is provided is not so limited because the generated gas to be discharged has a high degree of freedom of movement, and the generated gas escapes from the mold 12 as uniformly as possible, for example, only on the upper surface of the mold 12. There is no problem if they exist homogeneously.

[0031]

[Manufacturing Method] A manufacturing method for obtaining the colored melamine foam 10 from the melamine foam raw material M using the manufacturing apparatus 30 will be described with reference to FIGS. 3 and 4. Basically, the manufacturing method of the colored melamine foam 10 is a raw material preparation step in which all the raw materials including the coloring material 16 which is the base of the colored melamine foam 10 to be produced in the raw material adjusting / kneading section 32 are mixed and kneaded to prepare. S1 and the injection / foaming part 4
A colored melamine foam 10 having an outer contour shape that matches the inner contour shape of the molding die 12 is obtained by injecting a melamine foam raw material M in an amount that is intentionally controlled to 0 into the molding die 12 and foaming / curing. Obtaining injection / foaming step S2
And a final step S3 in which post-processing such as polishing into a predetermined shape and a predetermined inspection are performed on the obtained colored melamine foam 10 (see FIG. 3).

The raw material preparing step S1 is a step of producing a raw material of the colored melamine foam 10 to be obtained. Specifically, with respect to melamine as a main raw material, formaldehyde, a required color material 16, a foaming agent, a foaming auxiliary agent, an emulsifier,
In this step, a melamine foam raw material M is obtained by mixing a surfactant, a pH adjuster, etc. and an additive such as a curing catalyst.

In place of the melamine and formaldehyde, a melamine-formaldehyde precondensate prepared in a separate step in advance may be used. The number average molecular weight of those preferably used as the precondensate is 200
It is about 1200, especially about 200 to 400. In this case, the time required for condensation can be shortened and the production efficiency can be improved. When preparing the melamine-formaldehyde precondensate, the molar ratio of melamine and formaldehyde is melamine: formaldehyde = 1: 1.5: 1:
A range of 4, especially 1: 2 to 1: 3.5 is preferred.

Further, as a monomer for suitably producing the melamine-formaldehyde precondensate, a part of the melamine and formaldehyde may be replaced with another monomer. Examples of the monomer corresponding to the melamine include alkyl-substituted melamine, urea, urethane, carboxylic acid amide, dicyandiamide, guanidine, sulfurylamide, sulfonic acid amide, aliphatic amine or phenol or a derivative thereof, etc. As the monomer, acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde,
Furfurol, glyoxal, phthalaldehyde, terephthalaldehyde and the like can be mentioned. Colored melamine foam 1 to be obtained by substituting these other monomers.
An effect of arbitrarily controlling the hardness of 0 can be expected.

Examples of the foaming solvent added as the additive include pentane, trichlorofluoromethane, trichlorotrifluoroethane and the like. The catalyst as a curing catalyst is usually formic acid, and the emulsifier is sodium alkylsulfonate. Anionic surfactants such as those mentioned above are used. Further, as described above, a pH adjusting agent is appropriately used which secures fluidity to such an extent that the reaction proceeds more than necessary until the injection into the mold 12 in the next step and the injection is not hindered.

The foaming / drying step S2 is performed as described above.
After the melamine foam raw material M obtained in the raw material preparation step S1 is intentionally injected into a required molding die 12 in a controlled amount, the molding die 12 is closed, and foam molding is performed under a volume restriction. This is a process of drying, and a mold injection step S2
1, a mold closing step S22, a foaming step S23, and a drying step S24 (see FIG. 3). The foaming / drying step S2
Each step S21 to S24 of FIG. 4 will be described step by step with reference to FIG. 4. First, the melamine foam raw material M is injected into the mold 12 in an open state (mold injection step S21: see FIG. 4 (a)). ). Then, the mold 12 in which the intentionally controlled amount of the melamine foam raw material M has been injected is closed (mold closing step S22: see FIG. 4B).

Then, the molding die 12 is closed.
Is transferred to a predetermined position by the transfer means 42 and the foaming step S23 and the drying step S24 are performed. In the case of this embodiment, the microwave irradiation device
Used as the drying means 44, the melamine foam raw material M is foamed by being heated by microwaves.
After the completion of the foaming and curing, the energy of the microwave irradiation is used for evaporation of formaldehyde and water which are by-products generated during foaming, that is, for drying the obtained colored melamine foam 10 (FIG. 4 (c). )
(See the related art [0010] for details).

The mechanism of obtaining the homogeneous colored melamine foam 10 from the melamine foam raw material M being foamed in the foaming step S23 will be explained with reference to FIG. 5 as follows. Microwave irradiation heats a part of the melamine foam raw material M to start foaming (see FIG. 5 (a)). Foaming due to the generation of gas starts at the heated portion, and similar foaming also starts at other portions with a slight time difference. At this time, there is a difference in the degree of foaming described above due to a slight time shift in the start (see FIG. 5 (b)).
Such foaming occurs in each part of the melamine foam raw material M, and the foaming progresses over time, so that the melamine foam raw material M being foamed spreads throughout the molding die 12 (Fig. 5 (c)). At this time, the color material 1 homogeneously mixed with the melamine foam raw material M
No. 6 tends to shift to an inhomogeneous dispersed state due to the inhomogeneous foaming of the melamine foam raw material M.

When the foamed state reaches this state, expansion due to further foaming is restricted by the molding die 12, that is, by volume (see FIG. 5 (d)). Under such a volume limitation, the expanding skeletons press each other, thereby reaching a shape equilibrium and stabilizing. Specifically, those of small size have not yet completed condensation / curing,
That is, it is taken in by a large one due to the movement of the movable constituent material of the skeleton (see FIG. 5 (e)). As a result,
Eventually, the skeleton reaches a geometrical equilibrium due to unity of cells and the like and is stabilized at a certain size to have a uniform skeleton structure, that is, the coloring material 16 is uniformly dispersed in the skeleton structure to cause color unevenness. In this state, condensation and curing of the skeleton are completed, and the skeleton shape is fixed.

In the present embodiment, for continuous production, the foaming / drying means 44 is constructed so as to be capable of heating the mold 12 in the middle of the transfer path of the transfer means 42. The transfer means 42 may be stopped at the position where it reaches the foaming / drying means 44 for a time required for foaming / curing and drying.

Also regarding the foaming / drying means 44,
You may make it comprised for each function, ie, two for foaming and hardening, and for drying. In this case, it becomes possible to optimally set the energy required for foaming / curing or drying, respectively, and as a result, it is possible to reduce the manufacturing cost and to perform microwave irradiation capable of achieving uniform heating for the foaming. Regarding the drying, it is expected that the obtained colored melamine foam 10 will be optimized by a suitable method using a hot air oven at a softening point or lower.

The microwave irradiation is preferably used because it can uniformly heat the entire melamine foam raw material M, that is, it can form a uniform foam structure. At that time, the microwave irradiation is preferable. The electric power consumption at that time is set within a range of 500 to 1200 kW, preferably 600 to 800 kW, for 1 kg of the raw material. This is because if the power consumption is too low, it will not foam sufficiently, and if it is too high, the pressure of the raw material during foaming will be very high, and the raw material may scatter and the shape cannot be retained or an explosion may occur. Is considered. Further, the foaming / drying means 4
As for 4, in addition to microwave irradiation, conventionally known appropriate means such as normal heating or irradiation with electron beam or high frequency can be adopted.

The final step S3 that is finally performed is a step of releasing the obtained colored melamine foam 10 from the mold 12 and performing post-processing such as polishing into a predetermined shape and predetermined inspection. Thus, the colored melamine foam 10 as the final product is completed by passing through this step S3.

In the present embodiment, the production apparatus 30 capable of continuously producing the colored melamine foam 10 by using a plurality of molding dies 12 is given as an example, but the present invention is not limited to this, and for example, A so-called batch-type manufacturing apparatus in which each of the steps of pouring, mixing / kneading, foaming / drying and post-processing of the melamine foam raw material M is individually performed may be employed.

In the case of the conventional slab foaming method, since the foaming range is not limited in volume by using a molding die or the like in particular, the melamine foam raw material M subjected to microwave irradiation foams up to its foaming limit.・ Since it has expanded, there is a large difference in density between the central part and the end part, and the density is 1 even at the part close to the central part.
It will be reduced to about 0 to 20 kg / m ³ . When the foaming proceeds to such a low density, the three-dimensional network structure skeleton of the colored melamine foam 10 obtained by the microwave irradiation that can achieve the uniform foaming described above is between the central portion and the end portion. However, of course, it is empirically known that even the central portion becomes non-uniform. Therefore, in order to produce a colored melamine foam having a three-dimensional network structure in which the coloring material 16 is uniformly dispersed and has no color unevenness, the density thereof is at least 10 kg / m ³ or more, preferably 30 kg / m ³ or more. There is a need.

This is a molding die 12 having a limited space below the volume in which the injected melamine foam raw material M can foam, and the foaming is geometrically suppressed before the foaming limit is reached, that is, The three-dimensional network structure in the colored melamine foam 10 obtained by foaming under limited volume is made uniform to avoid occurrence of color unevenness.

On the other hand, the amount of the melamine foam raw material M injected into the mold 12 in the mold injection step S21 is determined by the density and the volume of the colored melamine foam 10 to be obtained, that is, the volume of the mold 12. To be done. Since the density needs to be at least 10 kg / m ³ or more, it can be said that the amount of the melamine foam raw material M to be injected is substantially determined only by the volume of the molding die 12. When calculating the injection amount, water and formaldehyde, which are by-products, and other volatile components from the melamine foam raw material M are discharged to the outside of the colored melamine foam 10. Therefore, it is necessary to determine them in consideration of their values. There is.

[0048]

[Experimental Example] The following shows an experimental example of the melamine foam to be obtained and the discharge holes formed in the molding die when the colored melamine foam is obtained by so-called molding using the molding die according to the embodiment. . The melamine foam and the manufacturing method thereof according to the present invention are not limited to this experimental example.

(Experiment 1) Relationship between the discharge hole of the molding die and the melamine foam to be obtained Methylol melamine obtained by precondensing formaldehyde with respect to melamine as a main raw material, a required coloring material, a foaming agent, and a foaming agent. 18 g of melamine foam raw material was prepared by mixing additives such as an auxiliary agent, a surfactant and a curing catalyst.
(True density 1260 kg / m ³ ) Weigh and stir with a stirrer at 3000 rpm for 45 seconds to homogenize the raw material, and then measure 160 mm × 110 mm ×
It is injected into a mold having a predetermined discharge hole of 20 mm (volume 352000 mm ³ ) and microwave irradiation is performed under the conditions of an output of 1 kW and 140 sec. Then, the obtained melamine foam is demolded, and then at 150 ° C. for 4 hours. Each of the test bodies according to Examples 1 to 3 and Comparative Examples 1 to 5 having a density of 30 kg / m ³ was obtained by drying under the above conditions. Then, for each of the obtained test specimens, the appearance state, skeleton state, color unevenness, and cell diameter are visually observed, and the appearance state is ○ / ×, the skeleton state is uniform to heterogeneous, and the color unevenness is I evaluated it with or without. The perforation pattern of the ejection holes perforated in the used mold and the total area thereof are shown in Table 1 below. The discharge holes are made of porous release paper so that the melamine foam raw material during foaming does not leak out.

The additives used and the amounts thereof mixed are as follows.・ Coloring material: Product name DISPERSE BLUE SD-6018; manufactured by Dainippon Ink and Chemicals (0.2 parts by weight based on 100 parts by weight of methylol melamine) ・ Foaming agent: tap water (15 parts by weight based on 100 parts by weight of methylol melamine) Part) ・ Foaming auxiliary: trade name HFE-7100; manufactured by Sumitomo 3M (5.1 parts by weight based on 100 parts by weight of methylol melamine) ・ Surfactant: trade name: Ripon LS-250; manufactured by Lion (100 parts by weight of methylol melamine) Curing catalyst: trade name formic acid (87%); manufactured by Mitsubishi Gas Chemicals (5.4 parts by weight per 100 parts by weight of methylol melamine)

[0051]

[Table 1]

(Results of Experiment 1) The results obtained are also shown in Table 1 above. For reference, data on a commercially available melamine foam produced by slab foaming is also shown.
Based on the obtained results, the discharge surface was used as a discharge hole of 0.
It has been confirmed that if an opening of about 2% or more is secured, a good colored melamine foam having a uniform skeletal state and no color unevenness can be obtained regardless of the opening portion. Also, the cell diameter was smaller (about 1/4) than that of the conventional slab foamed product. It is considered that this is because uniform foaming is performed.

The slab foaming test body described as a reference had a low density of 8 kg / m ³ and had a very severe color unevenness. In addition, there was a difference in the skeleton structure and color unevenness between the center and the end of the obtained test body, and it was confirmed that there was a good skeleton structure and no color unevenness near the center. When this part was cut out as a product, the ratio to the initial volume (corresponding to the product yield in this case) was only 25%.

(Experiment 2) Molding, that is, homogeneity of density and coloring of colored melamine foam obtained by molding Using the molding die of Example 1 which gave good results in Experiment 1 described above, Experiment 1 Using the same melamine foam raw material and conditions as described in 1., the injection amount (obtained colored melamine foam density) is 3 g as shown in Table 2 below.
(5 kg / m ³ ), 6 g (10 kg / m ³ ), 12 g (20 kg / m ³ ).
m ³ ), 24 g (40 kg / m ³ ) and 30 g (50 kg / m
³ ) Comparative Example 6 and Examples 4 to 7
A colored melamine foam test body according to (also described in Example 1 having an expansion ratio of 30) was obtained. Then, for each of the obtained test bodies, the appearance state, skeletal state and color unevenness are visually observed, and the appearance state is ◯ to ×,
The skeletal state was evaluated as being uniform to heterogeneous, and unevenness in color was present or not.

[0055]

[Table 2]

(Results of Experiment 2) The results obtained are also shown in Table 2 above. From this result, when the density is 10 kg / m ³ or more, a colored melamine foam having a better skeleton structure and less color unevenness was obtained as compared with the reference (test body by slab foaming) described in Experiment 1 above. Especially 30kg density
It was confirmed that a good colored melamine foam could be obtained in the case of / m ³ or more.

[0057]

As described above, according to the colored melamine foam and the method for producing the same according to the present invention, the melamine foam raw material added with the coloring material is applied to the required molding die.
By intentionally injecting a controlled amount and foaming under limited volume in a limited space, the desired density was achieved and a uniform three-dimensional network skeleton was used to eliminate color unevenness. It has become possible to manufacture melamine foam. Further, a colored melamine foam having a complicated three-dimensional shape can be easily manufactured. Further, with the slab foaming, it is possible to avoid the deterioration of the yield due to the end cut or the like, which cannot be avoided in manufacturing.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the inside of a skeleton of a colored melamine foam according to a preferred embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a manufacturing apparatus for manufacturing a colored melamine foam according to an example by molding.

FIG. 3 is a flowchart showing a method for producing a colored melamine foam according to an example.

FIG. 4 is a process drawing showing a foaming / drying process S2 related to a method for producing a colored melamine foam according to an example.

FIG. 5 is a step diagram for explaining homogenization of a skeletal structure during foaming of a colored melamine foam.

[Explanation of symbols]

10 Colored melamine foam 12 Mold 12b discharge hole 16 color materials M Melamine foam raw material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 105: 04 B29K 105: 04 (72) Inventor Hideo Suzuki 380-5 Horiyamashita, Hadano-shi, Kanagawa Stock company Inoac Technical Research Institute (72) Inventor Souko Nakajo 380-5, Horiyamashita, Hadano-shi, Kanagawa Innoac Technical Research Institute, F-term (reference) 3D026 AA02 AA15 4F204 AA38 AB12 AG20 AH81 EA01 EB01 EF01 EF02 EF27 EF01 EF47 EF47 EK47EK20EK EA02 EA03 EA04 EA05 EA45 EA51 EB21 EB22 EC05 EC08 HA01

Claims (7)

[Claims] 1. A desired coloring material (16) is added, and a melamine foam raw material (M) in an intentionally controlled amount is injected into a required molding die (12) to foam under a volume limitation. By doing so, a colored melamine foam characterized in that it has an outer contour shape that matches the inner contour shape of the molding die (12) and is composed of a three-dimensional network skeleton of a melamine resin that is homogeneous and has no color unevenness. . 2. The colored melamine foam according to claim 1, wherein a water-soluble substance is used as the coloring material (16). 3. The obtained colored melamine foam (10) has a density of at least 10 kg / m ³ or more, preferably 30 k.
The colored melamine foam according to claim 1, which is set to g / m ³ or more. 4. A melamine foam raw material (M) to which a required coloring material (16) is added is prepared, and the melamine foam raw material (M) is injected into a required molding die (12), and the volume is limited. By foaming below, a foamed molded product having an outer contour shape that matches the inner contour shape of the molding die (12) is obtained, and at this time, the melamine foam raw material (M By intentionally controlling the amount of), the density of the obtained foamed molded article is set to a desired value, and a uniform three-dimensional network skeleton without color unevenness is formed during the foaming. A method for producing a colored melamine foam characterized by the above. 5. The method for producing a colored melamine foam according to claim 4, wherein the molding die (12) is provided with a discharge hole (12b) for discharging various gases generated during foam molding. 6. The method for producing a colored melamine foam according to claim 4, wherein the opening area of the discharge hole (12b) is set to at least 0.2% or more of the total surface area of the molding die (12). 7. The obtained colored melamine foam (10) has a density of at least 10 kg / m ³ or more, preferably 30 k.
The method for producing a colored melamine foam according to claim 4, wherein the method is set to g / m ³ or more.