JPH0565331B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a flexible elastic plate.

[Prior Art] Conventionally, flexible elastic plates used as stamps, rubber stamps, printing plates, etc. have been manufactured by press molding using metal molds made of vulcanizable rubber compositions such as aluminum.

However, this method required a great deal of labor and expense to manufacture the metal molds, and was not suitable for manufacturing many types of plates in small quantities. In addition, rubber compositions have poor flow during molding, so they are cut to fit the size of the mold, or cut into strips and placed in the mold before being molded. It takes time and effort to insert the material, and since vulcanization is also performed during press molding, the molding time is lengthened.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned points, and provides an inexpensive flexible elastic plate that can be easily made into patterns of multiple types or multiple pieces. The object of the present invention is to provide a method for manufacturing a flexible elastic plate that is suitable for high-variety, low-volume production using production molds and can significantly shorten molding time.

[Means and effects for solving the problems] According to the present invention, an intermediate plate for producing a nest is created by a photolithography method using a photosensitive resin, and a thermosetting resin is produced from the intermediate plate for producing a nest. The thermoplastic elastomer is injected into an injection mold made by attaching the mold insert made by copying it to the molded flexible elastic plate with the uneven surface side facing the cavity side in order to give the predetermined unevenness to the flexible elastic plate to be molded. A method of manufacturing a plastic elastic plate is provided.

FIG. 1 shows a schematic sectional view of a mold A for producing a flexible elastic plate according to the present invention. In Fig. 1, 1 is a mold insert made of thermosetting resin, 2 is a mold for fixing the insert, 3 is a gate, 4 is a gate side mold, 5 is a cavity, and 6 is a mold insert.
is a groove provided in the mold insert. Note that, in FIG. 1, illustration of a temperature regulating means through which a cooling medium or a heating medium flows for controlling the temperature of the mold is omitted. In addition, the mold, especially the gate mold 4,
Although not shown, it is preferable that a vent hole is provided for venting air or gas pushed out by the resin flowing from the gate. Furthermore, this vent hole can be connected to a pressure reducing means (not shown) for reducing the pressure at an appropriate timing, so that the pressure can be reduced.

The mold A for producing a flexible elastic plate includes a mold insert 1 having an uneven surface for imparting predetermined unevenness to the plate to be molded.
is fixed to the insert fixing mold 2 with an insert fixing device 7 such as a screw, with the uneven surface side of the insert 1 facing the cavity 5 side.

The present invention is characterized in that a flexible elastic plate is obtained by injecting a thermoplastic elastomer into the injection mold.

The thermoplastic elastomer used in the present invention exhibits rubber elasticity at room temperature, as described in the "Research Report on the Development of Plastic Elastomers" (edited in March 1982), but becomes plasticized at high temperatures. It is a polymeric material that can be molded and molded. This thermoplastic elastomer can be rapidly processed on molding machines used for thermoplastics, does not require a vulcanization step, and has strength properties similar to or better than reinforced vulcanized rubber without the addition of reinforcing agents. It has the following.

Specifically, thermoplastic elastomers include:
Examples include vinyl aromatic, polyolefin, ester, and urethane thermoplastic elastomers, and other thermoplastic elastomers that do not fall into these categories.

It has been found that vinyl aromatic thermoplastic elastomers are particularly suitable for stamps and rubber stamps due to their ink transferability and appropriate elasticity.

The vinyl aromatic thermoplastic elastomer is a copolymer consisting of a monovinyl-substituted aromatic hydrocarbon polymer block and a conjugated diolefin polymer block, and has the general formula (B-S) _o , (B-S) _o -B, (S-
B) _n -S (In the above formula, B is substantially a conjugated diolefin polymer block, and S represents a monovinyl-substituted aromatic hydrocarbon polymer block.
is an integer from 2 to 10, and m is an integer from 1 to 10. ) or the general formula [(BS) _o −] _n+2 X, [(SB) _o −] _n+2 X, [(BS] − _o B] − _n+2 X, [(S−B) _o −S] − _n+2 X (In the above formula, S and B are the same as above,
X represents, for example, a residue of a coupling agent such as silicon tetrachloride or tin tetrachloride, or a residue of an initiator such as a polyfunctional organolithium compound. m and n are integers of 1 or more. ) A radial block copolymer represented by:

Examples of monovinyl-substituted aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, and α-methylstyrene, with styrene being the most common.

Examples of the conjugated diene include 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene, but 1,3-butadiene and isoprene are common.

The molecular weight of the vinyl aromatic thermoplastic elastomer is preferably 10,000 to 500,000.

Next, thermoplastic elastomers other than the above vinyl aromatic thermoplastic elastomer will be briefly explained.

A polyolefin thermoplastic elastomer is composed of a soft segment, a polyolefin rubber part mainly made of ethylene propylene rubber, and a hard segment made of a polyolefin polymer part mainly made of polypropylene.

The ester thermoplastic elastomer is composed of a polyester portion as a hard segment and a polyether portion as a soft segment.

The urethane thermoplastic elastomer is composed of a polyurethane portion as a hard segment and a polyester or polyether portion as a soft segment.

Examples of thermoplastic elastomers other than those mentioned above include low crystallinity 1,2-polybutadiene, ethylene-vinyl acetate copolymer, and polyamide thermoplastic elastomer. Further, in some cases, two or more of the above thermoplastic elastomers may be used as a blend.

When a thermoplastic elastomer is used as an injection molding material, a suitable filler such as silicic anhydride, calcium carbonate, magnesium carbonate, titanium oxide, clay, etc. may be mixed with the elastomer. Such fillers can increase the hardness of the molded elastic plate and improve the adhesion and transferability of ink, but they reduce thermoplasticity, so they are used in appropriate amounts. Usually, these are used in an amount of 5 to 100 parts by weight per 100 parts by weight of the elastic body.

Furthermore, various organic or inorganic pigments may be added for the purpose of coloring the plate. Further, in order to improve the thermal stability, light resistance, oxidation resistance, etc. of the plate, a suitable stabilizer may be mixed.

Further, an appropriate amount of a suitable plasticizer may be mixed with the elastomer for the purpose of improving processability during plate production. The type of plasticizer is appropriately selected depending on the elastomer, and the amount of plasticizer added varies depending on the type of elastomer and plasticizer, but is usually used in the range of 1 to 50 parts by weight per 100 parts by weight of thermoplastic elastomer. . Plasticizers are also used to adjust the hardness of the plate and are usually used as softeners.

It may also be mixed with a suitable thermoplastic resin for the purpose of modifying the hardness, oil resistance, heat resistance, processability, affinity for ink, etc. of the plate.
In such cases, the amount used is usually 150 parts by weight or less per 100 parts by weight of the thermoplastic elastomer. For example, in the case of a vinyl aromatic thermoplastic elastomer, the hardness and processability can be adjusted by mixing polystyrene with the elastomer, or the hardness of the plate can be adjusted by mixing polyvinyl chloride, and organic solvents can be added to the ink. It is possible to improve solvent resistance when using .

In addition, the physical properties and processability of the plate are adjusted, and
Appropriate amounts of various resins may be added for the purpose of modifying the affinity for the ink.

In the manufacturing method of the present invention, a flexible elastic plate is obtained by injecting a thermoplastic elastomer into a cavity 5 through a gate 3 of a mold A shown in FIG.

The injection pressure (gauge pressure) is preferably 60 to 100 Kg/cm ² , more preferably 70 to 90 Kg/cm ² . By keeping the injection pressure low, it is possible to prevent wear and deterioration of the thermosetting resin mold insert. In order to set the injection pressure to a low predetermined pressure, it is preferable that a pressure sensor is provided in the mold, a signal from the pressure sensor is received by a control means, and the operation of the screw is controlled by the control means.

The thermosetting resin mold insert according to the present invention is manufactured by a photolithography method using a photosensitive resin.

In other words, the characters, symbols, etc. that should be attached to the flexible elastic plate.
A pattern, design, painting, photograph, etc. is photographed, and the photosensitive resin 9 is exposed through the photographic film 8 [FIG. 2a]. Here, as the photosensitive resin 9,
An example using a negative type material that becomes hydrophobic or solvent insoluble when irradiated with light is shown. A photosensitive resin 9 with a transparent film 13 such as a polyester resin film on the back side and a photographic film 8 on the front side is exposed to light from both the front and back sides, the exposed areas are made insolubilized by the solvent, and the unexposed solvent-soluble areas are washed away. For example, an intermediate plate 10 for manufacturing a nest is obtained [FIG. 2b].

Next, after putting the intermediate plate 10 for insert manufacturing into the mold 11, phenol resin, epoxy resin,
A thermosetting resin molding material 12 such as diallyl phthalate resin is poured in (FIG. 2c), heated if necessary, and hardened to produce the mold insert 1.

If the insert is manufactured by photolithography using photosensitive resin in this way, when creating a manuscript for photographing, the same pattern may be repeated or many different shapes may be included in the same manuscript. Therefore, mold inserts for multiple molds can be made extremely easily.

Note that positive-type photosensitive resins that become hydrophilic or solvent-solubilized when exposed to light can also be used; in this case, negative or positive resins may be used so that the exposed areas become hydrophilic or solvent-soluble after exposure Used in combination with film.

[Example] Next, the present invention will be explained with reference to Examples.

Example 1 A manuscript containing 20 types of patterns (figures, characters) was prepared and photographed to obtain a photographic film. Using this photographic film and a photosensitive resin APR (registered trademark of Asahi Kasei Kogyo Co., Ltd.) model ASA200, an intermediate plate for manufacturing inserts was prepared by photolithography.

This intermediate plate for manufacturing nests is placed in the center of the mold, the phenol resin molding material is placed inside the mold, stainless steel plates are placed on the top and bottom, and after hardening by heating and pressure, the stainless steel plates are removed and cooled. Then, the mold is removed, and the intermediate plate for manufacturing the insert is peeled off from the cured phenolic resin (mold insert).

The mold insert made of phenolic resin thus obtained was installed in a mold for injection molding as shown in FIG.

As a thermoplastic elastomer, styrene and 1,
Tufprene 740C (manufactured by Asahi Kasei Corporation, Tufprene is a registered trademark), which is commercially available as a block copolymer of 3-butadiene, was used. The temperature of the cylinder of the injection molding machine using Toughprene 740C supplied by Hotspee was set to 150℃ at the base, 140℃ at the middle, and 130℃ at the tip.
The sample was then injected into the above-mentioned mold maintained at 30°C to 40°C at an injection pressure of 80 kg/cm ² and for 5 seconds. Cooling is for 14 seconds and by repeating this injection molding cycle, Toughprene 740C with 20 different patterns is produced.
100 flexible elastic plates were manufactured. The uneven pattern of the flexible elastic plate was very clear, and all 100 pieces were good.

Next, 20 different patterns were cut out from the flexible elastic board and each was glued to a wooden support member to create 20 different stamps.
I was able to create 100 pieces. This stamp had good ink adhesion and transfer, and could be imprinted beautifully.

Example 2 In the same manner as in Example 1, stamps for New Year's cards containing 30 identical figures of cows for New Year's cards were created.

[Effects of the Invention] In the present invention, since an injection mold with a mold insert made of thermosetting resin is used, a very large amount of labor is required since conventional molds were made of aluminum or the like. It is extremely easy and inexpensive to make molds, which previously required a large amount of investment, and mold inserts made of thermosetting resin can be easily made into many different types. Plates that would otherwise not be cost-effective to produce can now be manufactured in an economically viable manner. In addition, since thermoplastic elastomers are used, they are plasticized at high temperatures and can be injection molded, making it possible to significantly improve the molding cycle compared to when molding conventional rubber compositions. Since the flexible elastic plate obtained by the present invention exhibits rubber elasticity, it has a feeling of use similar to that of conventional rubber stamps and rubber stamps.

In addition, by creating an intermediate plate for insert manufacturing using a photolithography method using photosensitive resin, and copying this with thermosetting resin to create a mold insert, we can create a plate with many identical patterns on the plate surface. or different characters,
A plate having many types of figures on the same plate can be produced extremely easily and inexpensively by photolithography.

Further, since the molding die according to the present invention has a mold insert made of thermosetting resin with the uneven surface side of the mold insert attached to the cavity side, different plates can be created by replacing the mold insert. It is very easy to switch to, and is suitable for high-mix, low-volume production.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a mold used for manufacturing the flexible elastic plate of the present invention, and Fig. 2 is a schematic sectional view of a mold used for manufacturing a mold insert made of thermosetting resin by photolithography using photosensitive resin. It is an explanatory diagram showing a process. 1... Mold insert, 2... Insert fixed mold, 3... Gate, 4... Gate side mold, 5... Cavity,
6... Concave groove, 7... Insert fixing tool, 8... Photographic film, 9... Photosensitive resin, 10... Intermediate plate for insert manufacturing, 11... Formwork, 12... Thermosetting resin Molding material, 13...transparent film.

Claims (1)

[Claims] 1. An intermediate plate for manufacturing inserts is created by a photolithography method using a photosensitive resin, and a mold insert created by copying from the intermediate plate for manufacturing inserts with a thermosetting resin is used as a flexible material to be molded. A method for producing a flexible elastic plate, which comprises injecting a thermoplastic elastomer into an injection mold that is attached with the uneven surface side facing the cavity side for imparting predetermined unevenness to the elastic plate.