JPH01155243A - Measuring method of optical density of molded article - Google Patents

Abstract

PURPOSE:To conduct a quality control efficiently, by a method wherein a molded article of a resin material to which a substance for adjusting an optical density is added is expanded to a prescribed thickness, and a measuring sample thus obtained is determined visually and further subjected to quantitative density measurement by a densitometer. CONSTITUTION:A flange 10 is taken out of a core shaft so as to check up the light-intercepting property of a spool of a cartridge. Next, the flange 10 is put on a base sheet 21 together with a window-frame-shaped spacer sheet 20, a cover sheet 22 is put thereon, and the flange 10 is calendered in a heat to be expanded to a prescribed thickness by a press. A measuring sample thus obtained is measured visually, so as to determine whether carbon black is dispersed and distributed averagely in a resin base. The sample wherefrom no abnormality can be discerned as the result of the visual checking is set on a stage 36, spot illumination is applied thereto, an impression voltage on a photomultiplier 46 is controlled so that a photoelectric output be fixed, and a voltage signal proportional to a transmission density is taken out in a linearizer 49 and displayed 55 digitally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the optical density of a molded article, particularly a molded article that requires light-shielding properties.

[Conventional technology]

The main body of a film cartridge for storing photographic film or the spool incorporated in a film cartridge is required to have a light-shielding function.

For this reason, these parts are generally molded from thermoplastic resin to which carbon black is added to prevent the film housed inside from being covered.

Carbon black powder used for this purpose is
pH 5 to 9, because it does not cause any chemical adverse effects on photographic film, such as fogging, fluctuations in film sensitivity, or adhesion to film, and because it is inexpensive, etc.
Furnace carbon black with an average particle size of 10 to 120 mμ, especially one with a pH of 6 to 8 and an average particle size of 15 to 50 mμ, is often used, and depending on the wall thickness of the molded product, resin base is added in a range of about 0.05 to 3% by weight. Added to materials.

The carbon black addition method involves adding a predetermined amount of carbon black to the resin base material, as well as other necessary additives.
A compounding method involves melting and kneading using a single or twin-screw kneader, or a master patch method in which master patch pellets are prepared by kneading carbon black into resin at a high concentration, and an appropriate amount of these master patch pellets are added to the resin base material. There are methods, and even liquid methods.

The resin material to which carbon black is added using this method is molded into the desired part using a molding die, but the amount of carbon black added must be sufficient to give the molded product sufficient light-shielding function. In addition, it is necessary that the carbon black is evenly and sufficiently distributed inside the molded product.

However, in reality, there are problems such as incorrect measurement of carbon black mixed into the resin base material, variations in the bonding strength of carbon black powder, insufficient kneading of the resin base material and carbon black, and even problems such as the resin material being mixed in the mold during molding. Due to non-uniform flow of the molded product, the produced molded product does not have a sufficient light-shielding function, and if it is made into a product as it is, there is a concern that light-shielding defects may occur.

For this reason, conventionally, the light-shielding properties of molded products have been confirmed through practical tests. For example, if the subject is a cartridge containing a spool obtained as a molded product, this practical test should be carried out from the surrounding area with the film stored.
After irradiating the film with 00,000 lux light for 10 minutes, the film is taken out from the cartridge in a dark room, developed and fixed, and the film density is examined.

[Problem that the invention seeks to solve]

However, the conventional measuring method as described above is disadvantageous in terms of cost because it takes time and manpower to develop and fix the film. Furthermore, since it is not possible to sample and check during molding, and the cause of defects is unknown, there is a risk that a large number of defective products will be manufactured.

In particular, in the masterbatch method, the resin base material and master patch pellets are mixed immediately before the molding operation, so it is necessary to check the quality of the molded product at an early stage to determine whether the mixing is appropriate.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method for measuring the optical density of a molded article, which allows the optical density of a molded article to be easily checked in a short time. do.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a molded article made of a resin material to which a substance for adjusting optical density is added, or a part of this molded article. , a measurement sample is obtained by spreading it to a predetermined thickness, and the optical density of this measurement sample is measured.

When producing a measurement sample, a molded product or a portion thereof is rolled out into a sheet using, for example, a heating press. The concentration of the measurement sample thus obtained is measured using an optical densitometer, but before this measurement, it is also possible to visually determine the state of dispersion and two distributions of the substance for adjusting the optical density.

[Effect]

According to the above method, by simply spreading the measurement sample to a predetermined thickness, visual judgment can be performed on the spot.Furthermore, the concentration can be quantitatively measured using a densitometer, and the test results can be obtained immediately. Therefore, efficient quality control is possible even during the manufacturing process.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

The second column shows a cartridge in which a spool to be measured for optical density is incorporated. The cartridge 1 houses a spool 3 in a cylindrical body plate 2, and caps 4.4 are fitted to both ends of the spool 3.

On the inside of the body plate 2, there is a beak shape with a light-shielding ribbon 5 attached.
A boat (film outlet) 6 is formed. The spool 3 consists of a film winding shaft 8 with bosses 7.7 formed at both ends, and the bosses 7.7 are rotatably fitted into shaft holes 9, 9 provided in the center of the cap 4.4. Further, a flange 10° 10 is integrally formed on the film winding shaft 8 so as to be located inside the camps 4, 4. film 12
The leading end of the film is pulled out from a port (not shown) in the body plate 2, and most of the remaining part is wound around the outer periphery of the film winding shaft 7.

The spool 3 is manufactured by integrally molding a thermoplastic resin material, but as shown in the figure, a portion of the spool 3 is exposed to external light, so it is necessary to have a light-shielding property. For this reason, the resin material used to make the spool 3 is, for example, polystyrene resin to which carbon black is added. Note that carbon black has a pH of 6 to 8. Furnace carbon with an average particle size of 15 to 50 mμ is suitable, and the amount added is 0.1 to 1% by weight depending on the wall thickness of the spool 3.
That's about it.

In order to check the light shielding properties of the spool 3, the flange 10
It is convenient to test the optical density using a sample of carbon black, but the thickness of the flange 10 is usually about 1 mm, and it is impossible to optically evaluate the state of dispersion and distribution of carbon black in that state. . Therefore, before carrying out the method of the present invention, the flange 10 is first attached to the spool 3.
Work is done to separate it from the

Although the flange 10 can be easily separated by hand, it is convenient to use a jig as shown in FIG. The spool 3 is connected to the base 15 and the extrusion block 16
When the knob 17 is rotated, the extrusion block 16 is held between the knob 17 and the guide screw 18 integrated with the knob 17.
The screw is fed and descends. As a result, the upper flange 10 is separated from the film winding shaft 8. By such a method, the flange portion 10 can be easily separated from the film winding shaft 8;
This is thought to be because the polystyrene resin that serves as the resin base material also contains impact-resistant polystyrene resin.

The flange 10 thus separated from the film winding shaft 8 is then rolled out to a constant thickness. When expanding the flange 10, as shown in FIG. 4, the flange 10 is placed on a base sheet 21 together with a window frame-shaped spacer sheet 20, and a cover sheet 22 is placed on top of the base sheet 21. Note that each of these sheets 20 to 22 is a 180 μm thick polyethylene terephthalate sheet with good flatness. This prevents the flange 10 from being stamped when the flange 10 is expanded while being heated by a press machine as will be described later.

The flange 10 sandwiched between the base sheet 21° and the cover sheet 22 together with the spacer sheet 20 is
It is inserted between an upper heater block 25 and a lower heater block 26 of a heating type tabletop press machine as shown in FIG. After rotating the handle 27 and lowering the upper heater block 26, the flange 10 is moved to the seat 2 by applying hydraulic pressure to the lower heater block side.
1゜22, upper and lower heater block 25゜2
6 and spread to the thickness of the spacer sheet 20, that is, 180 μm. In addition, during this spreading process, the upper and lower heater blocks 25, 26
As a result, the flange IO is heated to the extent that it becomes soft.

This heating temperature can be adjusted with a temperature setting knob 28, and the temperature can be checked with a thermometer 29. Further, the hydraulic pressure applied to the flange 10 is measured by a pressure gauge 30.
will be displayed.

In addition, in an example of this spreading process, the heating temperature is 140°C2
Pressure force 250kg, /cn! (Total press force: 8 tons).

Spacer sheet with a continuous heat resistance temperature of 160°C with a pressurization time of 15 seconds 20. Base sheet 21. No degeneration was observed in each of the cover sheets 22.

FIG. 6 shows the appearance of measurement samples 32 and 33 obtained by rolling out the flange 10 to a thickness of 180 μm. In measurement sample 32 of the same figure (A), carbon black was distributed in spots in the resin base material and kneading was insufficient, and in measurement sample 33 of the same figure (B), one distribution of carbon black was dispersed. It can be seen that the condition is satisfactory. This determination can be made by visual observation through the measurement samples 32 and 33. Of course, a more detailed inspection can be made by using a magnifying glass or a microscope during this visual observation.

As a result of this visual judgment, the measurement samples 33 for which no abnormality could be identified are set on the stage 36 of the densitometer, as shown in FIG. 1, and quantitative optical density measurements are performed.

Set the measurement sample 33 on the stage 36 and turn the lamp 3
7 is turned on, the illumination light from the lamp 37 enters the lens 38.
．． Measurement sample 3 on stage 36 via mirror 39
Spotlight 3. The light transmitted through the measurement sample 33 passes through the collimator lens 41. Lens 42. mirror 43,
The light enters the photomultiplier 46 via the filter 44.

The photoelectric output from the photomultiplier 46 is input to a high voltage circuit 47 via an amplifier 48. The high voltage circuit 47 connects the photomultiply 46 so that the photoelectric output from the photomultiplier 46 is constant.
In order to control the voltage applied to the photomultiplier 46, the voltage generated due to this control is proportional to the amount of light incident on the photomultiple 46, that is, the transmission density of the measurement sample 33, and this voltage signal is output to the linearizer 49. .

The linearizer 49 converts a voltage signal that logarithmically changes according to changes in the transmission density of the measurement sample 33 into a linear signal, and then outputs this signal to the analog calculation circuit 51. The analog arithmetic circuit 51 determines the difference between the zero point signal from the zero point storage circuit 52 and the signal from the linearizer 49 and sends it to the amplifier 53. This zero point storage circuit 52 stores, as a zero point, a value obtained when, for example, a plate-shaped object that does not transmit light is placed on the stage 36. The signal amplified by the amplifier 53 is digitally converted by the A/D conversion circuit 54, and then sent to the digital display circuit 55, where the density value is displayed.

By measuring the density value of the measurement sample 33 in this manner, it becomes possible to quantitatively determine the optical density of the flange 10 and the spool 3, that is, whether or not it has a sufficient light shielding function. Furthermore, if the flange 10 is separated from the spool 3 that has been confirmed to have a sufficient light-shielding function, a measurement sample is prepared from it, and it is set in the densitometer and the reference concentration is temporarily stored in the zero point memory circuit 52. From the specific density value displayed on the digital display circuit 55, it can be immediately determined whether the optical density of the measurement sample is sufficient. In addition, measurement sample 3
When measuring the optical density of No. 3, it is of course possible to measure the reflection density by applying illumination light from the top surface of the measurement sample 33.

Although the above has been explained according to the illustrated embodiments, this density measurement method is applicable to molded products that require light-shielding properties such as film cartridges and optical equipment in addition to the spool 3.
It can be applied to various things. In addition, the spacer sheet 20 for obtaining a measurement sample spread to a constant thickness can be made of resin other than polyethylene terephthalate, iron or non-ferrous metal, etc., as long as the thickness accuracy can be maintained well and it is heat resistant. You may also use the 4
゜Furthermore, the method of the present invention can be used not only to improve the color density of molded products molded with resin to which carbon black is added for light shielding, but also to improve the color density of molded products mixed with colorants and the dispersion of colorants.

The method can be similarly applied to the case of inspecting distributability.

〔Effect of the invention〕

As explained above, in the optical density measurement method of the present invention, a molded product made of a resin material to which a substance for adjusting optical density has been added, or a part thereof, is taken out and rolled out to a predetermined thickness. In order to prepare a measurement sample and measure the optical density of the molded product based on this measurement sample,
The optical density of molded products can be inspected quickly and easily, and the quality control of mass-produced molded products can be made more efficient. In addition, it is possible to further improve inspection efficiency by setting the thickness of the measurement sample to a value suitable for visual observation and making it possible to determine the dispersibility of the substance before quantitative inspection using a densitometer.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a densitometer used for concentration measurement according to the present invention. FIG. 2 is a sectional view of the cartridge. FIG. 3 is a schematic diagram of a jig used to separate the flange from the spool. FIG. 4 is an explanatory diagram showing a state before producing a measurement sample. FIG. 5 is an external view of a press machine used when producing measurement samples. FIGS. 6(A) and 6(B) are explanatory diagrams showing examples of measurement samples. 3...Spool 10...Flange 16...Extrusion block 20...Spacer sheet 21...Base sheet 22...Cover sheet 25...
Upper heater block 26...lower heater block 36...stage 37...lamp 41...collimator lens 46...photomultiple. Figure 2 Figure 3 Figure 4 Figure 6 (A) (B)

Claims (3)

[Claims] (1) Prepare a measurement sample by rolling out a molded product made of a resin material to which a substance for adjusting optical density has been added, or a part of this molded product, to a predetermined thickness. A method for measuring optical density of a molded article, characterized by measuring optical density. (2) The method for measuring optical density of a molded article according to claim 1, wherein the substance for adjusting the optical density is carbon black. (3) Optical density measurement of a molded product according to claim 1, wherein the molded product is a spool for a photographic film cartridge, and a part of the molded product is a flange formed integrally with the spool. Method.