JP5559572B2 - Clay-like modeling material and its crosslinking method - Google Patents

Description

The present invention relates to a clay-shaped modeling material, in particular, a thermosetting clay-shaped modeling material whose shape can be fixed by a heat-curing treatment, and a crosslinking method thereof.

Known clay-like modeling materials that can be molded by hand work include clay, oil clay, paper clay, lightweight clay mixed with hollow balloons, and resin clay. Also, some of these clays can be cured by drying or heating, thereby losing the plasticity of the clay and fixing the shape of the modeled work, and making it possible to perform operations such as cutting and polishing after curing. There is also. For example, among plastic clays, plastic clay is known which can be heat-treated in an oven or the like after the work is formed to turn the formed work into a non-plastic hard product.

Patent Document 1 discloses a clay-like modeling solid containing an uncrosslinked thermally cross-linked silicone rubber that is kneaded with a crosslinking agent that can be cross-linked in the atmosphere. Solid material is safe even if it is accidentally put in the mouth, is not easily brittle even if left in the air for a long time, and is suitable for sheet-shaped molding. It is disclosed that a shaped article can be obtained.

JP 2009-103935 A

The solid material for clay-like modeling disclosed in Patent Document 1 is crosslinked by heating, and the document discloses that it is crosslinked by heating using an oven toaster, a hot plate or the like. It turned out that there was a problem that when the work was heated and cross-linked, there was a problem of "heat dripping" in the shaped work.

That is, when a modeling work that is usually modeled at room temperature is heated with an oven toaster or the like, it is gradually heated from the surface of the modeling work, and thus it takes a long time to sufficiently raise the temperature to the inside of the modeling product. On the other hand, resin materials such as silicone rubber increase in plasticity and easily deform when the temperature rises. For this reason, if the temperature of the modeled work is slowly increased to a temperature at which the crosslinking reaction of the silicone rubber sufficiently proceeds, there is a problem that the modeled product is heated by its own weight in the process of increasing the temperature.

When the problem of heat dripping occurs, it becomes necessary to put a core material into the work, or restrictions on the work shape that can be heat-crosslinked, resulting in restrictions on the creation of a shaped work.

In addition, when the modeled work is large, heating is insufficient, the center of the modeled work cannot be heated sufficiently and remains in an uncrosslinked state, May cause durability problems.

An object of the present invention is to provide a clay-like modeling material capable of solving the problem of heat dripping in a heating and crosslinking step in a clay-like modeling material that can be crosslinked by heating. Another object of the present invention is to provide a clay-like modeling material that can be uniformly cross-linked to the center of the modeled work.

As a result of intensive studies, the inventor has configured the clay-shaped modeling material to include an uncrosslinked resin material that can be heat-crosslinked , generates heat by microwave irradiation, and converts the microwave absorber including a specific metal compound into a clay-like shape. When knead | mixed with modeling material, after shape | molding a modeling work with modeling material, it came to be able to carry out heat bridge | crosslinking process by microwave irradiation, and discovered that at least 1 of the said subject could be solved, and completed this invention.

The present invention is used for modeling work by handwork of modeling works for handicraft use, educational use and art work use, and fixes the shape of the modeling work with clay-like modeling material containing uncrosslinked resin material that can be crosslinked by heating In order to achieve this, it is a method of crosslinking in the air without using a mold, which generates heat by microwave irradiation and contains magnetite, nickel zinc (NiZn) ferrite, or manganese zinc (MnZn) ferrite. This is a method in which a microwave absorber is kneaded into a clay-shaped modeling material, and the clay-shaped modeling material is formed into a shape of a modeled work by modeling work by hand, and then crosslinked by microwave irradiation (Claim 1 ).

According to the present invention, when a modeling work is subjected to heat crosslinking treatment, it can be heated using microwaves, and the entire modeling material is quickly heated to prevent or suppress heat dripping during the heating crosslinking treatment. be able to. In addition, according to the present invention, since the entire clay-shaped modeling material in which the microwave absorber is kneaded generates heat, it is possible to obtain an effect that it is possible to uniformly crosslink to the center of the modeled work.

In the present invention , magnetite, nickel zinc (NiZn) ferrite or manganese zinc (MnZn) ferrite is used as the microwave absorber in the present invention, and the above effect is more effectively exhibited by the high heat generation performance of these substances. The

It is a schematic diagram in case the degree of heat dripping by heat crosslinking treatment is small. It is a schematic diagram when the degree of heat dripping by heat crosslinking treatment is large.

Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to the individual embodiments shown below, and can be implemented by changing the modes as described later.

The clay-like modeling material of the present invention includes an uncrosslinked resin material that can be crosslinked (cured) by heating as its main material, and a microwave absorber that generates heat by microwave irradiation is kneaded. In addition, the clay-like modeling material of the present invention may contain a reinforcing material, a colorant, and various additives. The clay-like modeling material of the present invention has a clay-like plasticity so that the modeling operation can be easily performed by hand-bending operation or the like.

The uncrosslinked resin material contained as a main material in the clay-shaped modeling material of the present invention has plasticity during modeling, and is cured by a crosslinking reaction of the resin material by heating after the modeling operation to fix the shape of the modeled work. Such uncrosslinked resin materials, such as non-crosslinked materials such as silicone rubber and butyl rubber, and thermosetting such as millable acrylic resin, urethane resin, epoxy resin, etc. Examples of the resin material in an uncrosslinked state can be given.

These uncrosslinked resin materials may be blended with a crosslinking agent and a curing agent that are activated by heating. As the crosslinking agent and the curing agent, known publicly effective crosslinking of each resin material is possible. A crosslinking agent or the like can be used. For example, if a millable type silicone rubber material is used as the resin material, an acyl-based or alkyl-based peroxide can be used as the cross-linking agent, or a peroxy ester or a perketal can be used.

As the microwave absorber which is a component kneaded in the clay-like modeling material of the present invention, a material containing a substance that generates heat by absorbing a microwave of 900 to 5000 MHz can be preferably used. In particular, it is preferable to select and use a substance containing a substance having high heat generation performance by microwaves in the vicinity of 2450 MHz used for home microwave ovens.
The microwave absorber is not particularly limited as long as it can be kneaded with the clay-like modeling material and can raise the temperature to such an extent that the modeling material can be heated and crosslinked. In order to knead and disperse in the clay-shaped modeling material, the microwave absorber is preferably in the form of powder or particles. If necessary, the microwave absorber may be subjected to surface treatment such as coating or coupling agent treatment for the purpose of facilitating kneading with the uncrosslinked resin material.

Examples of the exothermic substance contained in the microwave absorber include metal compounds such as magnetite, ferrite, and conductive metal oxide, conductive carbon, and carbon fiber. The powders of these substances can be used directly as a microwave absorber, or can be used in the form of particles hardened with a binder or the like. In the case where the exothermic substance is in a liquid state, a liquid exothermic substance encapsulated in a microcapsule can be used as the microwave absorber.

Among exothermic substances, metal compounds are preferably used in terms of good temperature rise characteristics, and in particular, magnetite, nickel zinc (NiZn) ferrite, and manganese zinc (MnZn) ferrite can be preferably used. Among these three, the temperature rise characteristic of magnetite is the best, and then the temperature rise characteristic is excellent in the order of nickel zinc (NiZn) ferrite and manganese zinc (MnZn) ferrite.

The blending amount of the microwave absorber provides a plasticity that does not hinder the modeling work of the clay-like modeling material, and sufficiently obtains the temperature rise characteristics when the clay-like modeling material is heated and crosslinked by microwaves. It can be determined so that If the amount of the microwave absorber is too large, the plasticity of the clay-like modeling material is lost, and the workability of the modeling work tends to deteriorate, and the temperature rise rate becomes excessive and the temperature at the time of crosslinking of the modeling material can be adjusted. It may be difficult. Moreover, when there are too few compounding quantities of a microwave absorber, the heating by a microwave may become inadequate or a temperature increase rate may become slow, and the solution of the problem of a heat sink may become inadequate.

When silicone rubber is used as the main material and magnetite is used as the microwave absorber, about 10 to 300 parts by weight of magnetite is preferably blended with 100 parts by weight of silicone rubber, and about 20 to 200 parts by weight is blended. More preferably, about 30 to 100 parts by weight is particularly preferable.

When silicone rubber is used as the main material and NiZn ferrite or MnZn ferrite is used as the microwave absorber, it is preferable that the blending is approximately the same as or slightly larger than when magnetite is blended.

Magnetite, NiZn ferrite, and MnZn ferrite have high heat generation performance by microwaves, and sufficient temperature rise characteristics can be obtained with a relatively small amount of blending, so the plasticity of clay-like modeling materials can be reduced by adding a large amount of microwave absorber. It can be prevented in advance and is particularly suitable for the clay-like modeling material of the present invention.

The microwave absorber is preferably colored. By coloring the microwave absorber, the clay-like modeling material can be colored. If the clay-like modeling material can be made white or gray, it is preferable to make the clay-like modeling material white or gray because coloring is good when pigments of other colors are added. For this purpose, a transparent or translucent to white resin material such as silicone rubber is used as the main resin material, and the microwave absorber may be colored white or gray.

The means for coloring the microwave absorber is not particularly limited, and the surface of the powdered or granular microwave absorber may be coated with a colorant such as a pigment, or a heat-generating material and a colorant are kneaded. The colored microwave absorber may be obtained by powdering or granulating the powder. If it is colored white or gray, it is particularly preferable to use titanium oxide as a coloring pigment.

The manufacturing method of the clay-like modeling material of this invention is demonstrated. The clay-like modeling material of the present invention includes an uncrosslinked thermosetting resin material, a microwave absorber, a heat crosslinking agent such as a crosslinking agent and a crosslinking accelerator as necessary, and a reinforcing material (filler material) as necessary. In addition, it can be produced by blending and kneading colorants, additives and the like. Kneading can be performed by a known method such as a roll.

The usage method of the clay-like modeling material of this invention is demonstrated. The clay-like modeling material of the present invention has clay-like plasticity, and can be used for molding a modeling work by hand-shaped modeling work such as sheet-like or string-like, cutting or sticking. It is also suitable for clay work modeling work such as embossing, die cutting and spatula processing. In particular, when an uncrosslinked silicone rubber material is used as a main material, the workability of such modeling work is good.

After molding a modeling work with the clay-like modeling material of the present invention, the crosslinking work is activated by heating the modeling work with microwaves, the uncrosslinked resin material in the modeling material is crosslinked, and the modeling material becomes It hardens and the shape of the model is fixed. Here, if the uncrosslinked resin material is a rubber material, the shaped work has rubber-like elasticity. In addition, if the uncrosslinked resin material is a relatively hard resin, additional processing such as cutting and polishing can be performed after the molded article is cured.

In addition, even after molding a shaped work with the clay-like modeling material of the present invention, if it is still not in the state of heat crosslinking, it is still in a state of having plasticity, so modeling can be re-executed or reused. Is possible.

The function and effect of the present invention will be described. Since the clay-like modeling material of the present invention is kneaded with a powdered or particulate microwave absorber that generates heat by microwave irradiation, when the microwave is irradiated, the entire modeling material is exposed from the inside of the modeling material. Fever. In the case where the modeling material is heated in an oven or the like as in the conventional technique disclosed in Patent Document 1, since it is gradually heated from the surface of the modeling material, to be heated up to the inside of the modeling material Although it took time and the heating state was difficult to be uniform, if the modeling material of the present invention is heated by microwave irradiation, the entire modeling material generates heat from the inside of the modeling material. Can be quickly and uniformly heated.

According to the inventor's study, the problem of heat dripping is due to the fact that the plasticity of the material increases and the material fluidizes when the temperature of the uncrosslinked modeling material rises. It is a phenomenon that progresses slowly. Therefore, if it becomes possible to quickly raise the modeling material to a temperature at which the crosslinking reaction can be rapidly performed by microwaves according to the present invention, the modeling material can be crosslinked without giving a heat sink. Can be prevented or suppressed.

In addition, when the clay-like modeling material of the present invention is irradiated with microwaves, the entire modeling material generates heat from the inside of the modeling material, and heat generation occurs uniformly. The entire modeled work can be uniformly crosslinked and cured without being left in a crosslinked state.

Hereinafter, examples of the present invention will be described in more detail.
(Examples 1 to 16)
The raw materials shown in Table 2 were kneaded by a roll with the formulation shown in Table 1 to obtain a clay-like modeling material as an example of the present invention. In addition, all the compounding quantities in the mixing | blending of Table 1 are shown by the weight part. Here, silicone rubber A (X93-1159) and silicone rubber B (KE530B-2U) are millable uncrosslinked silicone rubbers mainly composed of polyorganosiloxane. Silicone rubber A is compared with silicone rubber B. Low viscosity makes it easy to knead and shape. On the other hand, the silicone rubber B has a relatively high viscosity, and the shape maintaining property of the shaped work becomes good.

Examples 1 to 4 and 9 to 11 are examples in which the blending amount of magnetite was gradually increased. Examples 4 to 6 were examples in which the crosslinking agent was changed. Examples 7 and 8 were the types of silicone rubber. It is an example that changed. And Examples 12-14 are the examples which mix | blended Mn-Zn ferrite as a microwave absorber, and Examples 15 and 16 are the examples which mix | blended Ni-Zn ferrite as a microwave absorber.

The plasticity in the uncrosslinked state after kneading of Examples 1 to 16 is the plasticity measured by a Williams plastometer according to JIS K6249 “Testing method for uncured and cured silicone rubber” (after 10 minutes of standing time). ) In the range of 10 to 250, and has a preferable plasticity as a clay-like modeling material. Table 1 shows the test results of the crosslinking characteristics when the modeling materials of these examples were heated and crosslinked by microwaves.

(Comparative Examples 1-4)
As a comparative example, roll kneading was performed with a formulation (Comparative Examples 1 to 4) that does not include a microwave absorber as shown in Table 3 to obtain a clay-shaped modeling material of a comparative example. The blending amount of the filler material is adjusted so that the plasticity of these comparative examples has the same hardness as in Example 4. Table 3 also shows the test results of the crosslinking characteristics when Comparative Examples 1 to 4 were subjected to HAV crosslinking (hot air heating crosslinking). In addition, although it tried to heat-crosslink the modeling material of the mixing | blending of Comparative Examples 1-4 with the microwave, the modeling material of these comparative examples was not able to be heated with a microwave, Therefore, it was not able to bridge | crosslink.

(Comparative Examples HA1 to HA11)
In addition, the composition (clay-like modeling material) shown as Examples 1 to 11 was tested for crosslinking characteristics when HAV heating was performed instead of microwave heating, and when the clay-like modeling material of the present invention was microwave heated. The superiority of the heat dripping prevention effect was confirmed. The test results of the crosslinking characteristics of HAV crosslinking for the compositions of Examples 1 to 11 are shown in Table 4 as Comparative Examples HA1 to HA11.

Characteristic evaluation of the obtained clay-like modeling material was performed as follows.

In the cross-linking property test, 15 cc of the obtained modeling material was weighed and formed into a spherical shape having a diameter of 30 mm, and this was left on a flat plate for cross-linking treatment.
In Examples 1 to 16 of the present invention in which a microwave absorber was kneaded, microwaves with a frequency of 2450 MHz were irradiated to the spherical cross-linking test sample by a household microwave oven, and the test sample was heated and cross-linked. Table 1 shows the irradiation time required to crosslink the samples when each test sample was irradiated with microwaves at an output of 700 W.

As is clear from Table 1, it was confirmed that the greater the amount of microwave absorber blended, the greater the amount of heat generated by microwave heating, which reached the crosslinking temperature by short-time microwave irradiation and could be crosslinked. Even when the blending amount is 20 or less, if the microwave irradiation time is increased or the output of the microwave is increased, crosslinking is performed in the same manner as in the examples described in Table 1.

On the other hand, the same molding was performed on the clay-like modeling material of the comparative example, and a heat crosslinking treatment was performed. However, since the clay-like modeling materials of Comparative Examples 1 to 4 are not heated and cross-linked even when irradiated with microwaves, in Comparative Examples 1 to 4, the test sample was placed in an oven heated to 150 degrees or 200 degrees for a predetermined time. By placing, heating and crosslinking treatment was performed. Also in Comparative Examples HA1 to HA11, the test samples were similarly left for a predetermined time in an oven heated to 150 degrees or 200 degrees to perform heating and crosslinking treatment.

After the crosslinking treatment, the degree of crosslinking was evaluated visually and by touch. Tables 1, 3 and 4 show the evaluation results. In the table, × indicates a state in which the rubber is in an uncrosslinked state and still has plasticity and the surface is solid, and Δ indicates that the rubber is Cross-linked is no longer plastic, but slightly sticky, so-called under-crossed state, ○ indicates that the rubber is well cross-linked and has no stickiness on the surface, ◎ indicates that the heat treatment for cross-linking is somewhat It is excessive and the rubber is slightly over-cross-linked.

In the clay-like modeling material of the present invention (Examples 1 to 16), in all examples, the modeling material was crosslinked and cured to the inside by microwave irradiation for 20 seconds to 120 seconds. In Examples 1, 2, 6, 7, 8, 15, and 16, the surface stickiness remained somewhat, but the rubber had been cross-linked, and was no longer plasticized.

On the other hand, in the test samples of Comparative Examples 1 to 4 and Comparative Examples HA1 to HA11, most of the samples were crosslinked to the inside of the sample when subjected to HAV heating at 150 ° C. for 10 minutes or 200 ° C. for 5 minutes. However, in any sample, heating at 200 ° C. for about 2 minutes remained in an uncrosslinked state, and HAV heating could not be crosslinked in a short time of about 2 minutes. This is presumably because the HAV heating only heats the surface of the sample, so that heat escapes to the inside due to heat conduction inside the modeling material, and the temperature of the sample does not rise easily. If HAV heating is performed at a higher temperature, the sample surface may be cross-linked even by heating for about 2 minutes, but it is considered that cross-linking to the inside of the sample is difficult.

In addition, in the modeling material of the comparative example 3, it was not able to bridge | crosslink by HAV heat bridge | crosslinking, and it remained in the uncrosslinked state. This is because the acyl peroxide used as a crosslinking agent does not crosslink in the presence of carbon. Moreover, about the comparative example 4, some stickiness was seen on the surface of the sample which carried out HAV heat bridge | crosslinking, and it was a little undercrossing.

In addition, since the samples of Comparative Examples HA5, HA6, and HA8 are crosslinking agents whose crosslinking agents are not very suitable for crosslinking in air, in Comparative Example HA5, the sample surface is considerably sticky although it is crosslinked. In Comparative Examples HA6 and HA8, it remained almost uncrosslinked.

Therefore, according to the clay-like modeling material of the embodiment of the present invention, it is possible to quickly heat the modeling work in a short time using microwave heating, and it is possible to uniformly cure the entire modeling work to the inside. It was. In addition, it was thought that if microwave heating was used to rapidly crosslink a shaped work as in the present invention, it was not suitable for crosslinking in the air, such as alkyl peroxides. It was confirmed that cross-linking in the air was possible even when a cross-linking agent was used.

Moreover, the degree of heat dripping at the time of performing the crosslinking treatment was evaluated by the following method.
In the visual evaluation, the degree to which the shaped work 1 that was spherical before heating was deformed by the crosslinking treatment was evaluated. ◎ indicates that there is almost no change in the shape of the sphere, and ◯ indicates that the overall shape of the sphere does not change much, but the part where the lower part of the sphere contacts the flat plate is slightly collapsed (Figure 1). Tables 1 and 3 show △ when the entire sphere is slightly flattened, and △ (Fig. 2) when the entire sample is flattened and spreads in a dome shape so that the lower part of the sample melts. Table 4 shows the evaluation results.

As a method for quantitatively evaluating the degree of heat dripping, as shown in the figure, a spherical test sample with a diameter of 30 mm is left on a flat plate, and the test sample height H after the heating and crosslinking step is measured. Then, the thermal evaluation was quantitatively evaluated based on the height. In terms of the relationship with the qualitative evaluation of hot dripping, almost no change in shape is observed. If the level is qualitative, the sample height after the test is often 25 mm or more. If it is evaluation, the sample height after the test is often 20 to 25 mm. When the sample height after the test is less than 20 mm, the thermal dripping is conspicuous even in visual evaluation, and often becomes a qualitative evaluation of the Δ level. In many cases, the shape becomes wide, and the qualitative evaluation of the x level is often obtained.

In each of the clay-like modeling materials of Examples 1 to 16 of the present invention, each example has a qualitative evaluation of ◯ or ◎, and the sample height after the crosslinking treatment is 20 mm to 26 mm. The impact of is limited and well controlled. In Examples 7 and 8, the sample height measurement after the crosslinking treatment was not performed. However, since these samples tend to foam during the crosslinking treatment and the sample expands, it is an effective measurement. This is because no value was obtained. In Examples 7 and 8, as far as qualitative evaluation by visual observation is performed, very good heat-sink prevention properties are obtained.

In Comparative Examples 1 to 4, when heated at 150 ° C., severe heat dripping occurs that is x in the qualitative evaluation, and even in the case of heating at 200 ° C., it is Δ in the qualitative evaluation. It was confirmed that a level of dripping occurred. In Comparative Example 3, the sample height after crosslinking could not be measured because it was in an uncrosslinked state even after the crosslinking treatment.

In the comparative examples HA1 to HA11 in which the heating conditions were changed from those of the examples, when heated at 150 ° C., considerable heat dripping occurred as x or Δ in the qualitative evaluation, and heating was performed at 200 ° C. Even in this case, it was confirmed that a level of heat dripping that would be Δ in the qualitative evaluation occurred. In Comparative Examples HA6 and HA8, the sample height after crosslinking could not be measured because it was in an uncrosslinked state even after the crosslinking treatment.

As described above, according to the embodiment of the present invention, it was confirmed that the crosslinking treatment can be completed while preventing the heat sink of the shaped work by using the microwave heating.

The clay-like modeling material of the present invention can be used for a wide range of uses such as handicraft use, education use, art work use, or industrial product prototype production use, and has high industrial utility value.

1 Uncrosslinked test sample 2 Crosslinked test sample

Claims (1)

In order to fix the shape of the modeling work, the clay-like modeling material containing uncrosslinked resin material that can be crosslinked by heating, used for modeling work by handwork of modeling work in handicraft use, educational use and art work use, A method of crosslinking in air without using a mold,
Heat is generated by microwave irradiation, and a powdery or particulate microwave absorber containing magnetite, nickel zinc (NiZn) ferrite or manganese zinc (MnZn) ferrite is kneaded into a clay-like modeling material, A method of cross-linking by microwave irradiation after forming into the shape of a modeled work by modeling work by hand .

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