JPS62275721A - Manufacture of ivory-like keyboard substance - Google Patents

Abstract

PURPOSE:To obtain ivory-like keyboard substance excellent in realism by a method wherein stripes of more then one kind of filler-blended casein composition having different color tone are arranged in sheets and hot-presses and finally cured. CONSTITUTION:More than one kind of molding composition having different color tone is obtained by adding 25-85 parts of filler to realize ivory-like keyboard substance, 1-5 parts of colorant and 20-50 parts of water to 100 parts of casein. A sheet-shaped arrangement body 31, in which striped compositions A2 and B2 are arranged alternately, is obtained by charging A raw material composition from the upstream side of a first extruder 11 or from the direction indicated with the arrows A and B raw material composition from the upstream side of a second extruder 12 or from the direction indicated with the arrows B in order to perform two-color extrusion at a mixed extruding part 13. A sheet-shaped molded body, in which turbulent flow pattern 51 is produced in the distinct interface between the striped compositions A2 and B2, is obtained by heating said sheet-shaped arrangement body 31 under pressure. Next, the sheet-shaped molded body obtained as mentioned above is treated with formalin for curing.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention provides a keyboard material that has a pattern and characteristics very similar to ivory, which has excellent characteristics as a keyboard material for keyboard instruments. Regarding the manufacturing method.

(Prior Art) Ivory is highly valued by experts as a material constituting at least the surface of the keys of keyboard instruments such as pianos, organs, and accordions. This is thought to be because ivory ideally satisfies the following characteristics required as a keyboard material, rather than because ivory is originally a high-quality art material.

(a) Must have appropriate water absorption. This is required to absorb sweat from the player's fingers and prevent slippage due to sweat.

(b) It must have appropriate surface smoothness and friction coefficient. This affects the tactile sensation when pressing a key.

(c) It has an excellent appearance (despite the high level of landslides, it has excellent stain resistance).

(d) Must have appropriate hardness. This is required to provide a tactile feel when pressing keys and to prevent wear due to long-term use.

(e) Possess appropriate workability.

However, natural ivory, which has such excellent properties, has the disadvantage that demand cannot be met due to insufficient supply capacity.

In view of these circumstances, synthetic resins are widely used as keyboard materials because they generally have no problems in terms of supply. However, although synthetic resin keyboards are somewhat satisfactory in terms of appearance and workability, their surfaces are too smooth, making it easy for fingers to slip on them, and their lack of water absorption makes them especially slippery when sweating, which can lead to mis-touching. This caused some inconvenience. Furthermore, since the hardness is generally insufficient, wear during long-term use also becomes a problem.

In order to eliminate the above-mentioned disadvantages of synthetic resin keyboard materials, the present inventor has already proposed an ivory-like keyboard material made by blending casein plastic with a water-containing or non-water-containing inorganic filler (Unexamined Japanese Patent Publication No. No. 57-45592 and No. 57
-96046). Such filler-containing casein plastics are produced by kneading casein with a filler and water, molding, and then impregnating with formalin and hardening. The above technology takes advantage of the properties of casein plastic, which is a molded body of natural protein molding material, such as its great water absorption and compatibility with the human body (finger etc.), while also maintaining the hardness, thermal conductivity, heavy texture, etc. of ivory. It is believed that the disadvantage of being inferior to the conventional synthetic resin keyboard material can be eliminated by incorporating an inorganic filler, and an ivory-like keyboard material having superior properties compared to conventional synthetic resin keyboard materials can be obtained.

(Problems to be Solved by the Invention) However, when the filler-containing casein plastic described above is compared with natural ivory material, it still lacks in aesthetic appearance and realism. This is because the filler-containing casein plastic described above has a single appearance and cannot reproduce the annual ring pattern of natural ivory, that is, the flowing striped pattern that extends to the interior and is similar to the grain of wood.

On the other hand, multi-colored casein molding compositions have been co-extruded using a multi-cylinder extruder to form multi-colored patterns, but simple multi-colored extrusion molding is difficult due to the subtle differences between the interfaces of natural ivory. No flow pattern is formed.

In view of the above-mentioned points, it is an object of the present invention to provide an ivory-like keyboard material that has a flowing striped pattern that extends to the inside and has a more realistic feel.

(Means for Solving the Problem) As a result of research for the above-mentioned purpose, the present inventor has determined that at least one of two or more types of filler-containing casein base organisms having different color tones can be used in the form of strings, filaments, or strips. After arranging the entire sheet-like structure together with other compositions, the resulting sheet-like arrangement is heated and pressed to form stripes with a flow that extends to the interior, which is seen in natural ivory. We have found that this method is extremely effective for reproducing geometric patterns.

The method for producing an ivory-like keyboard material of the present invention is based on the above-mentioned knowledge, and more specifically, the method involves kneading two or more compositions of different color tones, each of which is made by kneading casein with a filler and water. For example, by two-color extrusion molding, these compositions are formed into strips to form a sheet-like array in which striped compositions of different colors are alternately arranged, and this sheet-like array is placed on its surface. The composition is characterized by being fluidized and formed into an integral sheet-like molded body by hot pressing in orthogonal directions, and the resulting sheet-like molded body is impregnated with formalin and hardened.

This invention will be explained in more detail below. In the following description, "%" and "part" are based on weight unless otherwise specified.

In the method of the present invention, two or more types of molding compositions having mutually different tones are obtained by kneading casein with a filler, water, and a coloring agent added as necessary.

As the casein, fine powder of rennet casein pulverized to 100 mesh or less is preferably used.

The type of filler is basically not limited, but in order to provide an ivory-like keyboard material, aluminum hydroxide or alumina hydrate, calcium sulfate hydrate,
Hydrous inorganic fillers such as hydrated calcium silicate, calcium hydroxide, magnesium hydroxide, basic magnesium carbonate, hydrated aluminum silicate, magnesium silicate, and hydrated silicic acid, or silicon oxide, calcium phosphate,
Inorganic fillers such as non-hydrous inorganic fillers such as alumina, calcium carbonate, barium carbonate, calcium sulfate, magnesium oxide, and titanium oxide are used. These fillers are used in a proportion of 10 to 200 parts, preferably 25 to 85 parts, per 100 parts of casein.

In addition to the above-mentioned components, the molding composition further contains pigments such as titanium oxide and zinc white in a proportion of 0 to 10 parts, particularly 1 to 5 parts, per 100 parts of casein, in order to adjust the color tone. Alternatively, a coloring agent such as an acid dye is added.

Each of the above-mentioned components is kneaded with 20 to 80 parts, especially 20 to 50 parts of water per 100 parts of casein using a crusher or the like. After kneading, it is preferable to leave the mixture at room temperature for about 5 to 24 hours to swell the casein to improve subsequent moldability.

Individual molding compositions are obtained by the above operations, and two or more types of molding compositions can be obtained by repeating this process, but the difference in color tone between the compositions is due to the amount of filler or colorant blended. given by change. However, if the amount of filler blended differs greatly between compositions, the properties such as dimensional change rate will differ partially in the cured product, which may cause cracking or peeling at the interface. It is preferable that the difference in the blending amount of fillers including fillers is kept to 10 parts or less based on 100 parts of casein.

Differences in color tone are preferably provided by varying the amount of colorant by 0.1 to 2 parts.

Next, an embodiment of producing an ivory-like keyboard material according to the present invention from two or more types of molding-like compositions will be described.

In this specification, the term "striatum" refers to a thread-like body, a string-like body,
The term is used to include band-shaped bodies and rod-shaped bodies.

A molding composition of these 2FiI is formed and arranged alternately to obtain a sheet-like array. For this purpose, two types of compositions formed into strips formed by extrusion from an appropriate nozzle can be arranged alternately. The sheet-like array can be produced by sequential multi-color extrusion, for example two-color extrusion. This is because the plasticizer for casein molding is water, and since the molding is carried out at a high temperature close to the boiling point of water, extrusion molding is preferable since it can avoid evaporation of water.

In this case, as shown in FIG. 1, which is a plane axial cross-sectional view of the two extruders (also showing the typical temperature distribution of each part), the A raw material composition is A raw material composition B is introduced from the upstream direction B of the second extruder 12, and two-color extrusion is performed from the mixing extrusion section 13. A partial cross-sectional view of the mixing section 13 seen from the oblique front direction of the mold is as shown in FIG. As shown in FIG. 4, which is a cross-sectional view, a sheet-like array 31 having a thickness of, for example, 1 to 2 mm and in which striped compositions A2 and B2 are alternately arranged is obtained.

Next, the sheet-like array 31 thus obtained is sandwiched between a pair of hot plates and heated and pressurized, thereby forming the striped composition A2 in the sheet-like array 31.
, 82 is disturbed, resulting in a sheet-like molded product having a flow pattern 51 as shown in FIG. 5. This heat-pressure process is carried out at a temperature of 80 to 95°C and a pressure of 1
This is done by holding at 00-150 kg/cd for 15-30 minutes.

FIG. 6 and FIG. 7 are for explaining one preferable embodiment of hot pressing, and the sheet-like array 31 obtained as described above is arranged in several sheets (in this example, four sheets) in the horizontal direction as necessary. Sheet)
The whole is surrounded by a rigid wall that is slightly thinner than the sheet-like array body 31 to prevent leakage, and the upper and lower surfaces are sandwiched between releasable sheets such as polyester sheets, and then the above-mentioned Heat and pressure treatment is performed. As a result, the sheet-like array 31 is crushed as a whole, and a turbulent or flowing pattern is generated at the interface between the striped compositions A2 and 82. At this time, a composition flow occurs on the surface of the sheet-like array 31,
Particularly on the surface near the edges, the flow is so strong that some of the pattern disappears. However, even with such an end, there is no problem because the pattern emerges from the inside through the polishing process when the obtained material is finished into a keyboard.

Furthermore, when forming a sheet-like array by two-color extrusion, as shown in FIG. 9 corresponding to FIG. 4, by changing the shape of the mold, the striped compositions A2 and 82 are on the other hand(
In this example, it is also preferable to make B2) 10 to 20% thicker than the other to form the protrusion. Such protrusions of the sheet-like array 32 are crushed in the heat-pressing process and smoothed by increasing the width of the composition B2. Otherwise, a disordered pattern is effectively generated. At this time, in order to suppress the fluidity in the heat-pressing process of the strip composition to be protruded, the following (a)
It is also possible to adopt the means of ~(c).

(a) The water content of composition A is made higher than that of composition B2. The difference in water content is 20 parts per 100 parts of casein.
Parts or more, particularly preferably 30 parts or more. Also,
In this way, making the water content in one of the compositions higher than that of the usual casein plastic molding composition,
It is also preferred for increasing the adhesion between the two compositions.

(b) The temperature of the hot plate in contact with composition B2 is 80-85.
°C1 The temperature of the hot plate in contact with composition A2 is set at 90 to 95 °C, with a temperature difference of about 5 to 10 °C between the two to facilitate plasticization of composition A2.

The hot plate is brought into contact with the composition A2 about 3 to 5 minutes earlier than the contact between the composition B2 and the hot plate.

The difference in fluidity between compositions as described above can also be achieved by varying the amount of filler blended.

Next, the sheet-like molded product obtained as described above is subjected to a formalin hardening treatment, but before that, if necessary, the molded product is dried with hot air at 50 to 80°C to reduce moisture to 0 to 5.
%. This is because if the water content of the molded product before formalin treatment is high, the dimensional stability of the cured product will decrease, especially in a high humidity atmosphere.

Next, the thus dried molded body is immersed in about 3 to 10% formalin at around room temperature to harden the casein. The soaking time varies depending on the dimensions of the molded body, but in the case of a plate-shaped body, for example, 6 days at a thickness of 3 mm. 5 ■ for 16 days,
10mm is about 50 days.

The molded cured product is first air-dried to reduce the moisture content to about 10%, and then dried at a temperature of 20 to 45°C for 2 to 5 days to bring the moisture content to 4 to 6%. If deformation occurs here, put it in boiling water for a few minutes, heat it, pressurize it at low pressure, and then reapply for 30 to 30 minutes.
Humidity control drying is performed at 40°C, and the final moisture content is 3 to 4%. Further, if necessary, the keyboard material according to the present invention can be obtained by performing post-processing such as cutting, cutting, polishing, etc.

In the above description, an example using two types of molding compositions has been described, but it will be easily understood that the above method can be carried out using three or more types of molding compositions.

The keyboard material according to the present invention obtained as described above is
It can be the key itself or a key surface material composited with other materials, and in the latter case, it is attached to the key-pressing part on the surface of the key base material, which is mainly made of wood or the like.

〔Effect of the invention〕

As described above, according to the present invention, at least one of two or more filler-containing casein molding compositions having different color tones is formed into a strip, and together with the other compositions, the whole has a striped pattern in plan view. By arranging the resulting sheet-like array into a sheet-like structure that contains ivory, heat-pressing the resulting sheet-like array, and then curing it, it has a flowing striped pattern that extends to the inside, creating a texture that is extremely similar to natural ivory. A keyboard substance is obtained that does this.

[Brief explanation of the drawing]

1 to 9 are explanatory diagrams of the manufacturing process of a keyboard material according to the method of the present invention. FIG. 1 is a plan axial cross-sectional view, and FIG. 3 and 4 are respectively a plan view and a sectional view of the sheet-like array, FIG. 5 is a sectional view of the sheet-like molded product after hot pressing, and FIGS. 6 to 8 are FIG. 9, which is an explanatory diagram of another embodiment of the pressing process, is a sectional view of another example of the sheet-like array. 31 32... Sheet-like array body, 41.42... Sheet-like molded body, 6... Rigid body frame, 7... Mold release sheet, A, B... Molding composition (subscript 1.2 means sheeted and striated, respectively). Applicant's agent Mr. Sato Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1.Made by kneading casein with filler and water2.
A sheet-like array body is formed in which compositions having different tones of different colors are prepared, and each of these compositions is formed into strips by extrusion molding. The composition is fluidized by hot-pressing the arrayed body in a direction perpendicular to its surface to form an integral sheet-like molded body, and the resulting sheet-like molded body is impregnated with formalin and hardened. A method for producing an ivory-like keyboard material having a flowing striped pattern.