JPH04197718A - Ultraviolet ray impermeable injection-molded resin substrate - Google Patents

Abstract

PURPOSE:To obtain a UV ray impermeable injection-molded resin base sheet and to improve the productivity by incorporating a substance having a UV ray shielding effect, dispersing uniformly it in a resin and performing injection molding. CONSTITUTION:Those substances which have a UV ray shielding effect are generally treating agents for fibers etc., known as a fluorescent brightener and a UV ray absorber. In addition, any resins that can be injection-molded are usable and e.g. as a thermoplastic resin, acrylonitrile-butadiene-styrene resins etc., are cited and as a thermosetting resin, epoxy resins, polyimides, silicone resins, unsatd. polyester resins, acrylic resins etc., are cited. The content of the substance having a UV ray shielding effect in the resin is in the range of 0.1-3.0% when both substances are mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed wiring board obtained by injection molding.

[Prior Art] Conventionally, for printed wiring boards, a reinforcing material such as paper or glass cloth is impregnated with a resin such as phenol, unsaturated polyester, epoxy, or polyimide to form a prepreg, and this is laminated with copper foil. Copper-clad laminates were obtained by hot-pressure molding, and then processed with wiring, or ceramics were well known and often used.

On the other hand, in recent years, the emergence of resins with excellent heat resistance and electrical properties has led to the emergence of resins with excellent heat resistance and electrical properties.
Attempts have also been made to manufacture substrates by injection molding, as shown in Japanese Patent Application Laid-open No. 799 and Japanese Unexamined Patent Publication No. 2-175220.

According to this injection molding method, it is not only easy to manufacture boards, but also 3D printed wiring boards can be manufactured because it is also possible to perform three-dimensional molding, whereas the shape of a laminate is limited to a flat plate. It is possible.

And the development is actually underway. This 3D printed wiring board is attracting attention as a next-generation electronic material because it is expected to have the effect of making electronic devices more compact by effectively utilizing the space inside the device, and to reduce costs in the process by simultaneous wiring processing on all sides of the board. ing.

One method of applying circuits to injection molded boards, such as three-dimensional printed wiring boards, is the so-called transfer method, in which a pattern is printed on a film with conductive paste, etc., to create a transfer sheet, and this is used to transfer the circuit to the board. As you can imagine, this attempt has the following problems.

First, there are issues with circuit reliability, such as resistance uniformity and circuit breakage when subjected to heating cycles, and printing in three-dimensional shapes is also difficult. Above all, it is extremely difficult to simultaneously print both sides of a normal flat board, which actually increases the number of steps for applying circuits during manufacturing. This means that if the shape of the board becomes complex, simultaneous wiring processing over the entire surface is almost impossible.

In contrast to the above-mentioned transfer method using conductive paste, etc., the photographic method using an ultraviolet curable resist allows for the formation of arbitrary patterns using a photomask that corresponds to the shape of the molded product, and has complex three-dimensional shapes. This is a very effective method for applying circuits to injection molded substrates. In addition, it is extremely simple to process circuits on both sides of a flat board by irradiating both sides of the board with ultraviolet rays at the same time. This means that circuits can be applied to the entire surface of the board at the same time.

[Problems to be Solved by the Invention] However, when forming a plating resist or solder resist by a photographic method on an injection molded substrate having a normal flat plate shape or three-dimensional shape, ultraviolet ray exposure is applied to both the front and back sides of the substrate. When performing exposure on both sides or the entire surface of the substrate using three or more light sources, a problem arises called actual exposure in which the ultraviolet rays pass through the resin and the back side is also exposed to light.

[Means for Solving the Problems] As a result of extensive research in order to solve the problems in the previous term, the present inventors added a substance that has an ultraviolet shielding effect, uniformly dispersed it in resin, and performed injection molding. It has been found that by carrying out this method, a molded article that does not transmit ultraviolet light can be obtained, and based on this, the present invention has been completed.

That is, the gist of the present invention is an ultraviolet opaque injection molded resin substrate characterized by containing a substance having an ultraviolet shielding effect.

The substance having an ultraviolet shielding effect used in the present invention is a treatment agent for fibers and the like, which is generally known as an optical brightener and an ultraviolet absorber.

As the optical brightener, bis(triazinylamino)stilbene disulfonic acid derivatives, coumarin derivatives, pyrazoline derivatives, naphthalimide derivatives, bisbenzoxasilyl derivatives, bisstyrylbiphenyl derivatives, stilbene oxazole derivatives, etc. are used.

More specifically, for example, 2,5-bis(5-t-butylbenzoxasilyl(2))thiophene, 4-methyl-7-dinithylaminocoumarin, etc., or are limited to these. isn't it.

As the ultraviolet absorber, triazole derivatives, hensifenone derivatives, diphenyl acrylate derivatives, etc. are used.

More specifically, for example, 2-(2-hydroxy-5-
methylphenyl)hencytriazole, 2-(2-hydroxy-5-octylphenyl)hencytriazole, 2-(2-hydroxy-3,5-di-t-acylphenyl)benzotriazole, 2-(2-hydroxy -3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxyphenyl-
3-1-butyl-5-methyl)-5-chlorobenzotriazole, 2-hydroxy-4-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, ethyl-2-cyano-3 , 3-phenyl acrylate, etc.
It is not limited to this.

Any resin that can be injection molded can be used as the resin used in the present invention. For example, thermoplastic resins include acrylonitrile-butadiene-styrene resin, polyetheretherketone, polyetherimide, polyethersulfone, polytetrafluoroethylene, polycarbonate, etc., and thermosetting resins include epoxy resin, polyimide, etc. Examples include, but are not limited to, silicone resins, unsaturated polyesters, acrylic resins, and the like. Particularly preferred resins among them are acrylonitrile-butadiene-styrene resin, polyetherimide, polyether sulfone, and polycarbonate.

An insulating filler such as chopped strands of glass fiber, aramid fiber, or ceramic fiber can be mixed with the above resin.

Surface treatment of the insulator filler with a silane coupling agent or the like does not prevent this.

When a resin contains a substance that has an ultraviolet shielding effect,
If it is a resin or thermoplastic resin, it is mixed uniformly using an extorter to obtain pellets, and if it is a thermosetting resin, it is dissolved in a solvent and a substance that has an ultraviolet shielding effect is added, stirred, The usual method is to remove the solvent until the viscosity is suitable for injection molding, or it can be mixed directly in the injection molding machine immediately before molding.

The content of the substance having an ultraviolet shielding effect in the resin is 0.1 to 3.0%, preferably 0.1 to 3.0%, when the two are mixed.
It is in the range of 2 to 2.0%.

The heating and pressurizing conditions for manufacturing substrates by injection molding are selected depending on the shape of the substrate and the properties of the resin used, and are generally 200 to 390°C and 70 to 120 kg.
/car, in the range of 4 to 10 seconds.

After injection molding, the substrate is subjected to electroless plating or electrolytic plating, or bonded with copper foil by heating and pressure.

It is preferable to use a photographic method to apply wiring pressure to the injection molded substrate of the present invention. In the photographic method, as is generally done, an etching photosensitive material is laminated, a pattern film is attached, and the film is exposed.

It is preferable that two or more light sources are used for exposure, and exposure may be performed multiple times using one light source. There is no problem even if the number of light sources or the number of exposures increases as the shape of the injection molded substrate becomes more complex.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited thereby.

The following examples were carried out according to the following procedure.

As the resin, Denka ABS CL-301 grade (Denki Kagaku Kogyo Gen) was used.

The substance having an ultraviolet shielding effect was mixed with resin pellets in a container, and then uniformly contained in the resin using an extruder. The operating conditions for the extruder at this time were heating at 210° C. and screw kneading time for 20 seconds. A resin containing a substance having an ultraviolet shielding effect was obtained as pellets.

The pellet was injection molded to obtain a substrate. The molding conditions are
Heating at 210°C, pressurizing at 100kg/aff at the same time for 10
Seconds went. The shape of the board is 4QmmX90mmX2mm
It is a flat plate.

Using a substrate without copper plating, we measured its ultraviolet transmittance and backyard light.

In the measurement of ultraviolet transmittance, OHD-50 was used as the ultraviolet light source.
A 0M high-pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd.) was used. Its output is 500 watts and its dominant wavelength is 360 nm. The distance between the light source and the substrate is 30 cm. A UVMO2 illuminance meter (manufactured by Oak Seisakusho) was used as the ultraviolet transmittance measurement device.

In addition, in actual exposure measurements, the integrated irradiation energy amount was measured using the substrate coated with resist ink on one side under the above conditions, with the side coated with resist ink facing the light source.
The sample was exposed to light until it reached 0.00 millijoules, and the condition after exposure was confirmed visually and by touch. Actual exposure was determined when the resist ink clearly hardened.

Example 1 Optical brightener UVT as a substance with ultraviolet shielding effect
Using TEX OB (manufactured by Chiha Geigy), apply 1 to the resin.
．． The ultraviolet transmittance and actual exposure were measured using 0% by weight. The results are shown in Table 1.

Example 2 The ultraviolet absorber Sumisorb 300 (manufactured by Sumitomo Chemical Industries) was used as a substance having an ultraviolet shielding effect, and the resin was coated with 3.0
% by weight, and the ultraviolet transmittance and actual exposure were measured. The results are shown in Table 1.

Comparative Example 1 Injection molding was performed using resin pellets that did not contain a substance having an ultraviolet shielding effect, and the ultraviolet transmittance and actual exposure of the substrate were measured. The results are shown in Table 1.

Table 1 [Effects of the Invention] As shown in the above Examples and Comparative Examples, the injection molded substrate of the present invention has a low ultraviolet transmittance and no actual exposure occurs. This makes it possible to simultaneously process both sides of a flat printed wiring board using a photographic method, and also to process circuit wiring on an injection molded board having a complicated shape. In other words, since simultaneous processing of the entire surface using multiple light sources becomes possible, productivity can be improved in the production of injection molded substrates, and a significant cost reduction effect can be expected, especially when manufacturing injection molded substrates with complex shapes. .

In addition, the ability to prevent actual exposure also has the effect of making wiring processing of precise patterns possible using photographic methods.

Claims (1)

[Claims] (1) An ultraviolet opaque injection molded resin substrate characterized by containing a substance having an ultraviolet shielding effect.