JP3329647B2 - Distortion detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for non-destructively detecting a strain generated or remaining in a solid portion using a spectroscopic technique. The stress remaining in the resin molded product can be measured non-destructively, and can be effectively used for improving the quality of the resin molded product.

[0002]

2. Description of the Related Art Resin parts made of thermoplastic resins such as polypropylene, polystyrene, and nylon, and thermosetting resins such as epoxy resins and melamine resins can be found in everyday products, automobiles, trains, and other vehicles. became. In general, these resin parts are produced using injection molding, transfer molding, and pressure pressing, but the stress and distortion associated with the heat during molding remain and significantly affect the reliability of the resin parts. It is known to give.

That is, the yield of molding is reduced, and defects such as cracks and wrinkles are generated in parts after the molded product is taken out of the mold. It has also been pointed out that when a resin component is used for a long time, the durability of the component gradually decreases due to the influence of an external load, chemicals, ultraviolet rays, and the like. As an optical method for non-destructively measuring strain or stress generated or remaining in a solid portion, a photoelasticity method, a laser-Raman spectroscopy method, an X-ray stress measurement method and the like are known. The photoelasticity method utilizes birefringence. For example, Japanese Patent Application Laid-Open Nos. 62-124416 and 6-24191
As disclosed in Japanese Patent Publication No. 9 (1999), a polarizer and a detector are placed before and after a material or a molded product for measuring strain, and the observed interference fringes are counted. Since it is necessary, its application is limited to only transparent resin parts. Laser-Raman spectroscopy utilizes Raman shift when a material is strained (for example, Japanese Patent Application Laid-Open No. 3-220433), but has been applied only to specific materials such as silicon crystals and carbon fibers. It is said that application to resin parts is difficult. The X-ray stress measurement method (for example, “Non-destructive inspection technology series-Strain measurement B”, 1980, edited by Japan Non-Destructive Inspection Association) shifts the X-ray diffraction peak of the crystal due to the elastic deformation of the crystal,
That is, although the change of the crystal plane spacing is utilized, usually, most of the resin parts are amorphous materials, and in order to evaluate the strain, a large amount of metal powder or the like must be mixed. As a result, there is a concern that the mechanical properties of the resin itself may be impaired, or the magnitude and distribution of the remaining strain may be changed.

[0004]

SUMMARY OF THE INVENTION In view of the problems of the prior art, the present invention provides a non-destructive strain detecting method which is not affected by the shape and type of a sample and does not impair the mechanical properties of a resin part. The purpose is to do.

[0005]

The present inventors have conducted intensive studies on the optical properties of a resin containing a dichroic substance, and as a result, introduced a phthalocyanine, a phthalocyanine derivative, and a central metal as disclosed in JP-A-6-287461. Phthalocyanine or phthalocyanine with a central metal introduced
At least one species and iodine, wherein the iodine is I ₃ ^- or I _3
5 ^- dichromatic substance such as phthalocyanine iodine complex contained in the ion state of, and completed the present invention by finding that it is effective in the detection of the strain.

According to the distortion detecting method of the present invention, a step of embedding a dichroic substance in a solid part for detecting distortion, a step of measuring an ultraviolet-visible light absorption spectrum of the dichroic substance embedded in the solid part and the measurement And a detection step of detecting distortion based on the intensity ratio of the ultraviolet-visible light absorption spectrum obtained. The embedding step is preferably a mixing step of mixing a dichroic substance into a resin and a molding step of molding the resulting mixture to form a solid portion.

As the dichroic substance, it is preferable to use one selected from a phthalocyanine-iodine complex, an azo compound, an indigoid compound and a triphenylmethane compound.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A strain detecting method according to the present invention uses a two-color method in which a small amount of strain or stress externally applied to a solid part or the magnitude of shrinkage stress generated during part molding is previously embedded in a solid part. The intensity of the ultraviolet-visible light absorption spectrum of the active substance is detected based on a change in the intensity ratio as compared with the case where there is no distortion.

A dichroic substance is a substance that exhibits dichroism when the degree of light absorption differs between the direction of the molecular axis of the substance and the direction perpendicular to the molecular axis. For example,
Explaining using phthalocyanine represented by the chemical formula 1, when light is incident on a phthalocyanine having a planar structure from the lateral direction of the planar structure, the light component in the direction of the molecular plane is absorbed, and the light component in the direction perpendicular to the molecular plane is absorbed. Does not absorb and has dichroism. For example, a dichroic substance dispersed in a resin, when a distortion occurs in the resin, the dichroic substance tries to orient in the direction of the distortion, and the degree of orientation is proportional to the magnitude of the given distortion. . Therefore, the intensity of the ultraviolet-visible light absorption spectrum changes due to the given strain or stress.

[0010]

Embedded image

As the dichroic substance in the present invention, it is preferable to use one selected from a phthalocyanine-iodine complex, an azo compound, an indigoid compound and a triphenylmethane compound. The phthalocyanine referred to herein is a phthalocyanine having a substituent containing at least an atom such as carbon, nitrogen, oxygen, sulfur, halogen, silicon, and phosphorus at the X-position on the benzene ring of the phthalocyanine skeleton represented by Formula 1. . The central metal corresponds to M in the chemical formula 1, an alkali metal such as Na or K, an alkaline earth metal such as Mg or Be, AL, Si,
Pb, Sn, Zn, Os, Co, Cu, Ni, Mn, and the like. In addition, these central metals include CN, oxygen, sulfur,
A ligand containing a counter ion such as a halide, pyridine or pyrazine may be coordinated.

As shown in the schematic diagram of FIG. 2, the phthalocyanine-iodine complex is a crystal having a shape in which a column in which a large number of phthalocyanine molecules are stacked in parallel is bound by iodine in the I ₃ ⁻ and I ₅ ⁻ ion states. It has a structure. The phthalocyanine molecule exhibits different dichroism because the degree of light absorption is different between the plane of the phthalocyanine skeleton and the direction perpendicular thereto. Therefore, also in the phthalocyanine-iodine complex of FIG. 2, the phthalocyanine column in the axial direction (a direction)
The degree of light absorption is greatly different between the phthalocyanine / iodine complex and the direction perpendicular thereto (b direction), and the phthalocyanine / iodine complex has dichroism.

As the dichroic substance used in the present invention, azo compounds, triphenylmethane compounds and indigoid compounds exhibiting the same optical properties as those of the above-mentioned phthalocyanine-iodine complex can be used. Azo compounds include Oil Orange, Oil Orange SS, Oil Violet, Oil Red, Oil Red AS, Oil Red XO, Oil Yellow A
B, oil yellow OB, α-naphthol orange, β
Naphthol violet, naphthol yellow S, chrome violet, chrome yellow, acid red 8
8, Tartrazine, Acid Red 1, Acid Red 27, Chromotrobe 2B, Chromotrobe 8B, G2
39, C.I. I. Acid Blue 92, C.I. I. Acid blue 22 and the like containing one or two azo groups in the molecular structure.

Examples of the triphenylmethane compound include those having a triphenylmethane skeleton in the molecular structure of crystal violet, malachite green, acid green 3, acid green 5, acid blue 9, and the like. The dichroic substance used in the present invention, in addition to the above compounds, indigo compounds such as potassium indigosulfonic acid and indigo carmine, acylaminoanthraquinone, anthraquinonylamine, anthraquinonylcarbazole, indanthrone, flavantron, and biolanthrone Such as anthraquinone compounds, stilbene compounds such as chrysophenin G and Blancophor R, acridine compounds such as acridine orange NS and tripaflavin,
Alizarin compounds such as alizarin S and azine compounds such as nigrosine and safranin T can be used.

The above compounds are dichroic compounds similar to the phthalocyanine-iodine complex. The dichroic substance used in the present invention is ultraviolet light of 250 nm to 400 nm,
It absorbs visible light from 400 nm to 800 nm. The wavelength of light that can be absorbed depends on the chemical structure of the dichroic substance.

According to the distortion detecting method of the present invention, a dichroic substance of which the degree of distortion is detectable is dispersed and embedded in a solid portion to be subjected to distortion. Examples of the substance constituting the solid portion from which distortion is to be detected include a thermoplastic resin, a thermosetting resin molded product, and a rubber molded product. The dichroic substance used in the present invention is an organic substance and is easily mixed with a resin. Specifically, in the embedding step, a conventional mixing step such as kneading with a resin material, suspending or dissolving a dichroic substance in a solvent, and kneading the resin in that state can be employed. The resin raw material mixed with the dichroic substance can form a solid portion in a molding step employing a conventional molding method.

The dichroic substance may be dispersed not only in the resin matrix of the solid portion on the molecular order but also in the form of particles having a size of 1 μm. However, since the size of the dispersed particles may affect the mechanical properties of the resin molded product, the size is preferably several hundred nm or less. The mixing concentration of the dichroic substance may be 0.001% by weight to 0.5% by weight with respect to the resin, and does not affect the mechanical properties of the resin molded product itself.

The step of measuring the ultraviolet-visible light spectrum absorption of the dichroic substance buried in the solid portion is performed by 30 minutes from the excitation source.
Light from 0 nm to 800 nm is irradiated to detect light reflected by the substance, and its absorption spectrum is measured. The step of detecting the distortion based on the intensity ratio of the measured ultraviolet-visible light absorption spectrum includes an absorption spectrum of the dichroic substance in a state in which no distortion is applied in advance and a dichroic substance in which the distortion of an unknown solid part is measured. The change in the ratio of the intensity of the spectrum at a specific wavelength in the absorption spectrum is determined.

The dichroic substance in the strain detection method of the present invention is embedded in the matrix of the resin portion, is integrated with the resin portion, and receives the distortion and stress similarly to the resin portion. The dichroic material changes its molecular axis direction rapidly due to the strain and stress applied from the outside and the stress generated from the inside, so the degree of absorbing light from outside is more sensitive than before applying the strain or stress. Will change. As a result, it is considered that the intensity of the ultraviolet-visible light absorption spectrum of the dichroic substance changes due to strain and stress.

[0020]

The present invention will be specifically described below with reference to examples. FIG. 1 shows an outline of an ultraviolet-visible light absorption spectrum measuring apparatus used in the present invention. The ultraviolet-visible light absorption spectrum measuring apparatus includes an excitation source (flash lamp) 1, a detection unit (spectroscope + data processor) 2, and polarizing plates 3 and 4. In the test sample, strain and stress generated by stretching of the resin film were detected. Light of 300 nm to 800 nm was sequentially incident from the excitation source 1, and light reflected from the sample 5 attached to the tension jig 6 was sensed and processed by the detection unit. Note that the detection unit 2 and the polarizing plate 4 may be set on the side opposite to the incident light with respect to the sample to detect light transmitted through the sample.

(Example 1) Phthalocyanine of the formula 1
The complex with iodine (FIG. 2) was synthesized as follows. Tetra-t-butyl phthalocyanine copper (manufactured by Wako Pure Chemical Industries, Ltd.) 1
A solution was prepared by dissolving 00 mg and 40 mg of iodine (manufactured by Wako Pure Chemical Industries, Ltd.) in 10 mL of a chloroform solution. The two chloroform solutions were mixed and allowed to stand for one day to obtain a solution in which a phthalocyanine / iodine complex having a schematic structure shown in FIG. 2 was suspended. Then 2 mL of this suspension and poly (1,
1 g of 2-butadiene) (RB2, manufactured by Nippon Synthetic Rubber Co., Ltd.) was mixed and dissolved in 10 mL of chloroform. This solution was spread on a Teflon dish to obtain a sample having a thickness of 300 μm. This sample was attached to a tensile jig 6 shown in FIG. 1 at both ends with an instant adhesive (Alon Alpha, manufactured by Toagosei Co., Ltd.), and the visible light absorption spectrum at 400 to 800 nm was measured while stretching. FIG. 3 shows the visible light absorption spectrum. FIG. 4 is a plot of the ratio (vertical axis) of the spectral intensity between 680 nm and 500 nm in the spectrum of FIG. 3 with respect to the stretching ratio (horizontal axis). As shown in FIG. 4, it can be seen that the ratio of the spectral intensities decreases according to the stretching ratio.
That is, the ratio of the spectral intensity when the stretching ratio is 100% is
It is about half that of the case where the stretching ratio is 0%.

Example 2 1 mL of the phthalocyanine-iodine complex suspension prepared in Example 1 and 1 g of polymethyl methacrylate (manufactured by Aldrich) in chloroform 10 m
After mixing and dissolving L, the mixture was spread on a Teflon dish to obtain a sample having a thickness of 250 μm. When the sample was attached to a tensile jig in the same manner as in Example 1 and the change in the visible absorption spectrum due to stretching was examined, the ratio of the spectral intensity at 680 nm to 500 nm was 2.44 when the stretching ratio was 0%, and the stretching ratio was 1 It was 2.41 when it was 0.33%. That is, the ratio of the spectral intensities was reduced according to the magnitude of the distortion.

Example 3 The sample of Example 2 was treated at 80 ° C. for 4 hours.
When the ratio between the spectral intensities at 680 nm and 500 nm was measured after stretching by 0%, the intensity ratio was changed from 2.44 to 2.23 by stretching by 40%. That is, the ratio of the spectrum intensities became smaller depending on the magnitude of the distortion.

(Example 4) A film having a thickness of 300 was prepared in the same manner as in Example 1 except that magnesium tetra-t-butylphthalocyanine was used instead of the copper tetra-t-butylphthalocyanine.
A μm sample was prepared. For this sample, 400-8
When the visible light absorption spectrum at 00 nm was measured,
The ratio of the spectral intensity between 70 nm and 500 nm is 0
%, And 4.21 at a stretch ratio of 50%. The ratio of the spectral intensities decreased with the magnitude of the distortion.

(Example 5) 1 mg of azo compound G239 (manufactured by Nippon Kosaku Dye Laboratories) and poly (1,2-butadiene)
(RB2, manufactured by Nippon Synthetic Rubber Co., Ltd.) 1 g of chloroform 10
The mixture was mixed and dissolved in mL. This solution was spread on a Teflon dish to obtain a sample having a thickness of 150 μm. This sample was attached to a tensile jig, and an ultraviolet-visible light absorption spectrum of 300 to 700 nm was measured under stretching. 500 nm and 350
When the ratio of the spectral intensity in nm was determined, the ratio of the spectral intensity increased with the stretching ratio as shown in FIG.

Example 6 Dichroic substance G23 of Example 5
A sample having a thickness of 250 μm was prepared by using indigo carmine (manufactured by Nippon Kosaku Dye Laboratories) instead of 9 indigo. This sample was attached to a tensile jig 6 and the ultraviolet-visible light absorption spectrum of 300 to 800 nm was measured under stretching to determine the ratio of the spectral intensity between 600 nm and 360 nm. It was 0.745 at 40%, 0.756 at 40%, and 0.771 at 80%. That is, the intensity ratio increased according to the magnitude of the strain.

(Example 7) Dichroic substance G23 of Example 5
9 instead of triphenylmethane compound Acid Blue 9
A sample having a thickness of 250 μm was prepared using (manufactured by Tokyo Chemical Industry Co., Ltd.). This sample was attached to a tensile jig and stretched to 300
By measuring the UV-visible absorption spectrum of ~ 800 nm,
When the ratio between the spectral intensities of 600 nm and 360 nm was determined, the ratio of the spectral intensities was 3.1 when the stretching ratio was 0%.
It was 2.85 at 1,39% and 2.70 at 73%. That is, the intensity ratio increased according to the magnitude of the strain.

As described above, distortion can be detected using the characteristic that the intensity of the ultraviolet-visible light absorption spectrum changes depending on the magnitude of the distortion or stress. Depending on the type of dichroic material, the spectral intensity in the presence of distortion increases or decreases.

[0029]

According to the present invention, it is possible to simplify and accurately evaluate the durability of a resin component such as distortion, and as a result, a highly reliable resin component can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ultraviolet-visible light absorption spectrum measuring device.

FIG. 2 is a schematic diagram of the structure of a phthalocyanine-iodine complex.

FIG. 3 is a graph showing the wavelength dependence of the absorption spectrum of a sample in which the phthalocyanine / iodine complex used in Example 1 is dispersed.

FIG. 4 shows 680 nm and 500 n of the sample used in Example 1.
6 is a graph showing the draw ratio dependency of the ratio of the absorption spectrum intensity of m to the draw ratio.

FIG. 5 shows 500 nm and 350 n of a sample in Example 5.
6 is a graph showing the draw ratio dependency of the ratio of the absorption spectrum intensity of m to the draw ratio.

[Explanation of symbols]

1: excitation source, 2: detection unit, 3, 4: polarizing plate, 5:
Sample 6, tensile jig

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-185407 (JP, A) JP-A-6-287461 (JP, A) NODA I, DOWREY AE, MARCOTT C, Appl Spectrosc, Vol. 42, No. 2, P203-216 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/16 G01L 1/00 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A step of embedding a dichroic substance in a solid part for detecting distortion, a step of measuring an ultraviolet-visible light absorption spectrum of the dichroic substance embedded in the solid part, and a step of measuring the measured ultraviolet-visible light A distortion detecting method, comprising: detecting a distortion based on a spectrum intensity ratio. 2. The distortion detecting method according to claim 1, wherein the embedding step includes a mixing step of mixing a dichroic substance with the resin and a molding step of molding the obtained mixture to form a solid portion. 3. The strain detecting method according to claim 1, wherein the dichroic substance is one selected from a phthalocyanine-iodine complex, an azo compound, an indigoid compound, and a triphenylmethane compound.