JP2012233751A - X-ray contrast medium for use with resin, structural change detecting method and internal structure determining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray contrast medium for use with resin, a method of detecting change in an internal structure of a molded resin object by using the X-ray contrast medium for use with resin, and a method of determining an internal structure of a molded resin object by using the X-ray contrast medium for use with resin.SOLUTION: A specific hydrocarbon compound is used as an X-ray contrast medium for use with resin. The X-ray contrast medium for use with resin is intended to be permeated into a molded resin object to be used in analyzing the internal structure of the molded resin object, and is composed of a hydrocarbon compound having a higher mass absorption coefficient than that of the resin making up the molded resin object. It is preferable to use a halogenated hydrocarbon compound as the X-ray contrast medium for use with resin.

Description

  The present invention relates to an X-ray contrast agent for resin, a structure change detection method, and an internal structure determination method.

  It is known that physical properties such as mechanical strength of a resin molded body vary under the influence of the internal structure of the resin molded body. For example, it is known that in a resin molded body formed by molding the same raw material, physical properties are different when the crystallinity is different. In addition, when the resin molded body contains a filler, the physical properties of the resin molded body may fluctuate due to the influence of the dispersion state of the filler.

  Therefore, Patent Document 1 discloses a method for predicting the mechanical strength of a resin molded body using the crystallinity and orientation degree of the resin molded body. In the method described in Patent Document 1, first, multiple correlation data between the crystallinity and orientation degree of a resin molded body and the mechanical strength of the resin molded body is created by actual measurement. Next, the crystallinity and orientation degree of the resin molded body are determined by analysis based on molding conditions including molding conditions, shape, and resin characteristics of the resin molded body. Finally, the mechanical strength of the injection-molded product is predicted from the crystallinity and orientation, and the multiple correlation data.

Japanese Patent Laid-Open No. 10-156885

  The present invention relates to an X-ray contrast agent for resin, a method for detecting a change in the internal structure of a resin molded body using the X-ray contrast agent for resin, and an interior of the resin molded body using the X-ray contrast agent for resin. It is to provide a method for determining the structure.

  The present inventors have found that if a specific hydrocarbon compound is used as an X-ray contrast agent for a resin, it is possible to detect a change in the internal structure of the resin molded body and to determine the internal structure of the resin molded body. The present invention has been completed. More specifically, the present invention provides the following.

  (1) An X-ray contrast agent for resin for infiltrating into a resin molded body and analyzing the internal structure of the resin molded body, wherein the mass absorption coefficient is higher than the mass absorption coefficient of the resin constituting the resin molded body An X-ray contrast agent for resin composed of a hydrocarbon-based compound having a coefficient.

  (2) The X-ray contrast agent for a resin according to (1), wherein the hydrocarbon compound is a halogenated hydrocarbon compound.

  (3) The X-ray contrast agent for a resin according to (2), wherein the hydrocarbon compound is a halogenated aromatic hydrocarbon compound.

  (4) The X-ray contrast agent for resins according to (3), wherein the hydrocarbon compound is a compound containing either iodine or bromine.

  (5) The X-ray contrast agent for resin according to (4), wherein the hydrocarbon compound is either iodobenzene or bromotoluene.

  (6) The X-ray contrast agent for resin according to any one of (1) to (5) is permeated into a resin molded body, and the cross section of the resin molded body is photographed under conditions of two or more penetration times. A penetration rate for each depth in the direction in which the resin X-ray contrast agent penetrates is derived from the corresponding X-ray transmission image, and a change in the internal structure of the resin molded body is detected based on the change in the penetration rate. Structural change detection method.

  (7) The structural change detection method according to (6), wherein the X-ray transmission image is an X-ray CT image.

  (8) The structural change detection method according to (6) or (7), wherein the resin molded body is made of a crystalline thermoplastic resin.

  (9) The X-ray contrast agent for resin according to any one of (1) to (5) is permeated into the resin molded body, and the cross section of the resin molded body is photographed under conditions of two or more penetration times. By deriving the penetration rate for each depth in the direction in which the X-ray contrast agent for resin penetrates from the corresponding X-ray transmission image, and analyzing the information on the internal structure of the resin molded body for each penetration rate The X-ray contrast agent for resin used for deriving the relationship between the permeation rate and the internal structure and analyzing the X-ray contrast agent used for deriving the relationship is composed of the same resin as that constituting the resin molded body. Permeation speed per depth in the direction in which the X-ray contrast agent for resin penetrates from the X-ray transmission image of the resin molding for analysis, which was infiltrated into the resin molding and photographed under conditions of two or more penetration times And the analytical resin composition based on the permeation rate and the relationship. Internal structure determination method of determining the internal structure of the body.

  (10) The internal structure determination method according to (9), wherein the X-ray transmission image is an X-ray CT image.

  (11) The resin molded body is composed of a crystalline thermoplastic resin, and the information on the internal structure is the degree of crystallization of the analytical resin molded body or the orientation degree of the analytical resin molded body for each depth. The internal structure determination method according to (10).

  If the X-ray contrast agent for resin of this invention is used, the change of the internal structure of a resin molding can be easily detected from the change of the penetration speed to the resin molding of the X-ray contrast agent for resin. Moreover, the internal structure of the resin molded body can be easily confirmed by clarifying the relationship between the penetration rate and the structure inside the resin molded body in advance.

FIG. 1 is a schematic diagram showing an example of an X-ray CT apparatus. FIG. 2 is a schematic diagram showing an example of an X-ray CT image showing the relationship between the penetration time and the penetration distance. FIG. 3 is a diagram showing the relationship between the penetration speed and the penetration distance. FIG. 4 is a diagram showing the relationship between the information on the internal structure and the penetration rate. FIG. 5 is a diagram showing the shapes of samples used in Examples and Comparative Examples. FIG. 6 is a diagram showing the relationship between the increased weight (%) when the initial weight is 100% and the time after the sample is put into the metal pressure vessel. FIG. 7 shows an increase in weight (%) when the initial weight is 100% and the sample is put into a metal pressure vessel when the evaluation is performed under conditions different from the evaluation conditions adopted to obtain the result of FIG. It is a figure which shows the relationship with time since then. FIG. 8 (a) shows an increase in weight (%) when the initial weight is 100% when the evaluation is performed under conditions different from the evaluation conditions employed to obtain the results of FIGS. It is a figure which shows the relationship with the time after throwing into a pressure-resistant container. FIG. 8B is a diagram showing the relationship between the penetration distance obtained from the X-ray transmission image and the above time. FIG. 9 (a) is a diagram showing the relationship between the peak intensity ratio of the FT-IR spectrum and the depth of the measurement location when a resin molded body molded at a mold temperature of 60 ° C. is used. (B) is a figure which shows the relationship between the peak intensity ratio of a FT-IR spectrum, and the depth of a measurement location at the time of using the resin molded object shape | molded on the conditions whose mold temperature is 140 degreeC.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

<X-ray contrast agent for resin>
The X-ray contrast agent for resin is a hydrocarbon compound having a mass absorption coefficient higher than that of the thermoplastic resin. Since the X-ray contrast agent for resin needs to penetrate into the resin molding, it is liquid or gas.

  The thermoplastic resin contains carbon and oxygen, and depending on the type of resin, it contains heteroatoms such as oxygen and sulfur. “A mass absorption coefficient higher than the mass absorption coefficient of a thermoplastic resin” means an atom having a mass absorption coefficient higher than the mass absorption coefficient of the atom having the highest mass absorption coefficient among the atoms contained in the thermoplastic resin. It refers to a hydrocarbon-based compound.

  As the X-ray contrast agent for resin, for example, a hydrocarbon compound or an organometallic compound into which a halogen atom is introduced can be used. In the present invention, the use of a hydrocarbon-based compound into which a halogen atom has been introduced is preferable because it easily penetrates into the resin and has a high mass absorption coefficient.

  The halogen atom introduced into the hydrocarbon compound is not particularly limited, and may be any of fluorine, chlorine, bromine and iodine. In the present invention, it is preferable to use a hydrocarbon-based compound into which bromine or iodine has been introduced because it is in a liquid state in a wide temperature range up to a relatively high temperature and therefore is easily tested. In particular, iodine is particularly preferable because it has a very large mass absorption coefficient. A plurality of types of halogen atoms may be introduced into the hydrocarbon compound.

  In the hydrocarbon compound, a functional group other than a halogen atom may be introduced as long as the effects of the present invention are not impaired.

  The hydrocarbon compound into which a halogen atom is introduced is not particularly limited, and for example, either an aromatic hydrocarbon compound into which a halogen atom is introduced or an aliphatic hydrocarbon compound into which a halogen atom is introduced can be used. is there.

  The aromatic hydrocarbon compound may be either an aromatic hydrocarbon compound or an aromatic heterocyclic compound. In addition, the aromatic hydrocarbon compound may be monocyclic or polycyclic.

  In the present invention, as an aromatic hydrocarbon compound into which a halogen atom is introduced, iodobenzene, bromotoluene, and the like are preferable because they are easily available and it is easy to observe changes in the penetration rate into the resin.

  The aliphatic hydrocarbon compound may be either a chain hydrocarbon compound or an alicyclic hydrocarbon compound. The chain hydrocarbon-based compound may be linear or branched.

  Since the X-ray contrast agent for resin needs to permeate the resin molded body, it is usually liquid or gaseous. This permeation occurs when the resin X-ray contrast medium enters the gap between the entangled polymer molecular chains. Accordingly, if the gap is small, it is preferable to use an X-ray contrast agent for resin composed of a small hydrocarbon compound, and if the gap is large, an X-ray contrast agent for resin composed of a slightly large hydrocarbon compound. Can also be used. Thus, the ease of penetration is considered to depend on the type of thermoplastic resin constituting the resin molding and the molecular weight of the X-ray contrast agent for resin.

  Therefore, for example, a resin X-ray contrast agent having a molecular weight in the range of 100 to 400 can be selected as appropriate so that it can easily penetrate into the resin molding.

<Structural change detection method>
The structural change detection method of the present invention includes the following steps (a) to (c).
(A) a step of infiltrating the resin molded body with the X-ray contrast agent for resin,
(B) From the X-ray transmission image corresponding to the cross section of the resin molded body, taken under the condition of two or more penetration times, the penetration speed for each depth in the direction in which the resin X-ray contrast agent penetrates is derived. The process of
(C) The process of detecting the change of the internal structure of the said resin molding based on the change of the said penetration rate.

  The resin molded body to which the method of the present invention is applied is particularly preferably composed of a resin composition containing a thermoplastic resin. The thermoplastic resin is not particularly limited, and examples thereof include polyolefin resins, polyester resins, polyacetal resins, liquid crystalline resins, polyarylene sulfide resins, and the like.

  The resin composition may contain a plurality of thermoplastic resins, and may contain general additives such as a filler, an antioxidant, a stabilizer, and a pigment. However, in the case where a glass fiber, carbon fiber, glass flake or the like that impedes permeation is included, it is preferable to select an X-ray contrast agent for resin that easily permeates.

  The resin molding can be manufactured by molding the above resin composition by a conventionally known method. For example, an injection molding method, an extrusion molding method, etc. can be mentioned. Moreover, the shape of the resin molding is not particularly limited.

  Hereinafter, the structure change detection method of the present invention will be described by taking a case of using a rectangular parallelepiped resin molded body as an example.

[Step (a)]
An X-ray contrast agent for resin is infiltrated into the resin molding. The method for infiltration is not particularly limited. For example, the resin molded body can be penetrated by immersing the resin molded body in the X-ray contrast medium. The permeation rate is not particularly limited, but it is preferable to adjust the permeation rate so that the change in the permeation rate is easily observed. The penetration rate can be adjusted by selecting pressure, temperature, contrast agent, and the like.

  It can be confirmed by a change in weight or the like that the X-ray contrast medium for resin sufficiently penetrates into the resin molded body.

[Step (b)]
First, when the penetration time of the resin X-ray contrast agent into the resin molded body reaches t1, an X-ray transmission image of the resin molded body is acquired.

  The measurement of an X-ray transmission image can be performed using a conventionally known X-ray diffractometer. Specifically, first, the resin molded body is irradiated with X-rays. Next, the X-ray transmission amount of the resin molded body accompanying X-ray irradiation is detected by an X-ray detector. Finally, image processing is performed based on the detected X-ray transmission amount to obtain an X-ray transmission image.

  As described above, a method for capturing an X-ray transmission image is not particularly limited, but in the present invention, a method for obtaining an X-ray CT image by an X-ray CT apparatus is preferable. Therefore, an X-ray transmission image acquisition method will be further described by taking an example of using an X-ray CT apparatus.

  FIG. 1 shows an example of an X-ray CT apparatus. The X-ray CT apparatus 1 includes an X-ray irradiation unit 11 for irradiating the resin molded body 2 with X-rays, an X-ray detection unit 12 that detects X-rays transmitted through the resin molded body 2 as projection data, and resin molding. A sample stage 13 for holding the body 2, a rotation drive unit 14 for moving the sample stage 13 up and down (moving in the direction of the arrow in FIG. 1) and rotating (moving in the direction of the white arrow in FIG. 1); An image processing unit 15 that reconstructs projection data in a plurality of angular directions as an X-ray CT image.

  The X-ray irradiation unit 11 is a part for irradiating the resin molded body 2 with X-rays. It will not specifically limit if it can irradiate X-ray | X_line, A conventionally well-known X-ray irradiation apparatus can be used. For example, an X-ray tube etc. are mentioned. In the X-ray irradiation part 11, the irradiation conditions of the X-ray irradiated to the resin molding 2 can be adjusted. Examples of X-ray irradiation conditions include tube voltage, tube current, and X-ray irradiation time. In the present invention, the X-ray irradiation conditions are not particularly limited, and can be appropriately changed according to the shape of the resin molding to be predicted, the type of resin contained, and the like.

  The X-ray detection unit 12 is a part that detects X-rays transmitted through the resin molded body 2 as projection data after being converted into electric signals. The X-ray detection unit 12 is disposed so as to face the X-ray irradiation unit 11 with the resin molded body 2 interposed therebetween.

  The sample stage 13 is a part for holding the resin molded body 2 so that the resin molded body 2 is irradiated with X-rays. The sample stage is disposed between the X-ray irradiation unit 11 and the X-ray detection unit 12.

  The rotation drive unit 14 is a part for moving the sample stage 13 up and down and rotating it so that the resin molded body 2 is irradiated with X-rays from a plurality of angular directions. The rotation drive unit 14 is connected to the sample stage 13. The rotational drive unit 14 can irradiate various positions in the resin molded body 2 with X-rays from a plurality of directions. As a result, projection data can be obtained for X-rays transmitted through the resin molded body 2 from various angles.

  The image processing unit 15 is a part that reconstructs projection data in a plurality of angular directions as an X-ray CT image. The image processing unit 15 is connected to the X-ray detection unit 12. The projection data detected by the X-ray detection unit 12 is sent to the image processing unit 15, and an X-ray CT image is obtained by performing conventionally known image processing. The conventionally known image processing method is, for example, a method in which projection data in each direction is subjected to one-dimensional Fourier transform, these are combined to create a two-dimensional Fourier transform image, and this is subjected to inverse Fourier transform to obtain a reconstructed image. Is mentioned.

Next, based on the X-ray CT image, the penetration speed for each penetration depth is derived, for example, by the following procedure. FIG. 2A shows an example of an X-ray CT image. The rectangle drawn with the solid line is the outline of the cross section of the resin molding. The dotted line represents the position where the X-ray contrast agent for resin that has permeated from the left side surface of the resin molded body has permeated for the time of permeation time t1. Here, the direction in which the X-ray contrast agent for resin penetrates is a direction (x direction) perpendicular to the left side surface (surface through which the X-ray contrast agent penetrates). Therefore, the permeation distance L1 at the permeation time t1 is a distance between a solid line and a dotted line representing the left surface of the resin molded body, as shown in FIG. By dividing L1 by t1, the average penetration speed v1 up to the depth of the penetration distance L1 can be derived. This penetration speed v1 is defined as a penetration speed at a depth of the penetration distance L1. Other definitions such as the penetration speed v1 being the penetration speed at the position of L1 / 2 which is the middle of the penetration distance L1 may be used. Alternatively, the permeation speed v1 may be obtained by dividing L1 by (t1) ^1/2 according to Fick's diffusion law.

  Similarly, in the case of the penetration time t2 (t2> t1), an X-ray CT image is acquired, the penetration distance L2 is derived, and the penetration speed v2 ((L2-L1) / t2) is derived. Further, X-ray CT images are obtained in the same manner for the infiltration time t3 (t3> t2) and the infiltration time t4 (t4> t3), and the infiltration distance L3, the infiltration speed v3, the infiltration distance L4, and the infiltration speed v4 are obtained. To derive. L1, L2, L3, and L4 are shown together in FIG.

[(C) Step]
Assume that the relationship between the penetration speed and the penetration distance is as shown in FIG. 3, for example. From FIG. 3, it can be confirmed that the difference between V1 and V2 is small, the difference between V2 and V3 is large, and the difference between V3 and V4 is small. From this difference in permeation rate, it can be confirmed that there is a small structural change between L1 and L2, between L3 and L4, and a large structural change between L2 and L3.

  According to the structural change detection method of the present invention, the structural change inside the resin molded body can be confirmed without destroying the resin molded body. In the above description, the case where X-ray CT images at four penetration times are acquired has been described. However, since structural changes can be detected from two points of data (for example, X-ray CT images at penetration times t2 and t3), A structural change can be detected by checking X-ray CT images for at least two penetration times.

<Internal structure determination method>
The internal structure determination method of the present invention includes the following steps (A) to (F).
(A) The above-mentioned resin X-ray contrast agent is infiltrated into the resin molded body,
(B) From the X-ray transmission image corresponding to the cross section of the resin molded body, which is taken under the conditions of two or more penetration times, the penetration speed for each depth in the direction in which the resin X-ray contrast agent penetrates is derived. The process of
(C) Deriving the relationship between the penetration rate and the internal structure by analyzing information on the internal structure of the resin molded body for each penetration rate;
(D) a step of infiltrating the X-ray contrast agent for resin used for deriving the relationship into an analytical resin molded body composed of a resin similar to the resin constituting the resin molded body,
(E) A step of deriving a permeation rate for each depth in the direction in which the X-ray contrast agent for resin penetrates, from an X-ray transmission image of the analysis resin molded article taken under conditions of two or more penetration times. ,
(F) A step of determining the internal structure of the analytical resin molding based on the permeation rate and the relationship.

  Since the resin molded body used for the internal structure determination method is the same as the resin molded body described in the structure change detection method, description thereof is omitted.

[Step (A)]
The step of allowing the resin X-ray contrast agent to penetrate into the resin molded body can be performed by the same method as the step (a) of the structural change detection method, and thus the description thereof is omitted.

[Step (B)]
Deriving the penetration rate for each depth in the direction in which the X-ray contrast agent for resin penetrates from an X-ray transmission image corresponding to a cross section of the resin molded body, taken under conditions of two or more penetration times Since it can be performed by the same method as the step (b) of the structural change detection method, the description is omitted.

[Step (C)]
As shown in FIG. 3, the penetration distance at the penetration time t1 is L1, the penetration speed at the penetration distance L1 is v1, the penetration distance at the penetration time t2 is L2, and the penetration speed at the penetration distance L2 is v2. The penetration distance at the penetration time t3 is L3, the penetration speed at the penetration distance L3 is v3, the penetration distance at the penetration time t4 is L4, and the penetration speed at the penetration distance L4 is v4. Step (C) will be described as being obtained in steps (B) to (B).

  Information on the internal structure of the resin molded body is analyzed for each penetration rate. Specifically, information on the internal structure of the resin molded body at each of the penetration distances L1 to L4 is analyzed.

  The information on the internal structure of the resin molded body is information on density, crystallinity, orientation, and the like, for example. If the internal structure is different, the permeation rate is different. Therefore, if the correlation between the information and the permeation rate is derived in advance, the internal structure of the resin molded body can be determined based on the permeation rate. Therefore, it is preferable that the information regarding the internal structure of the resin molded body and the penetration rate have a one-to-one unique correspondence. In addition, when there is no one-to-one unambiguous correspondence, it is not possible to determine one piece of information from the penetration rate, but it is possible to make a decision by considering other physical property information. Note that information such as density, crystallinity, and orientation has a one-to-one unique correspondence with permeation rate.

  Information on the internal structure of the resin molded body can be measured by a conventionally known method according to the type of each information. Here, it is assumed that the information at L1 is I1, the information at L2 is I2, the information at L3 is I3, and the information at L4 is I4.

  For example, the higher the density and crystallinity, and the higher the orientation, the denser the polymer is packed, so the penetration rate of the resin X-ray contrast agent into the resin molding tends to be slower. is there. For example, a relationship as shown in FIG. 4 can be derived. It is preferable to derive an approximate expression of I = f (v) based on the four data in FIG. In addition, I represents the information regarding the internal structure of the resin molding, and v represents the penetration rate.

[Step (D)]
In step (D), an X-ray contrast agent for resin is infiltrated into the analysis resin molding to be analyzed. The resin molding for analysis is comprised from the resin composition similar to the resin composition which comprises the resin molding used at the (A) process. In addition, the same X-ray contrast agent for resin as that used in the step (A) is used. The specific penetration method is the same as (A).

[Step (E)]
In the step (E), as in the step (B), the penetration rate for each depth is derived from the X-ray transmission image under a plurality of penetration time conditions.

[Step (F)]
In step (F), the internal structure of the resin molding for analysis is determined based on the penetration rate derived in step (E) and I = f (v), which is the relationship derived in step (C). Specifically, I may be obtained by substituting the permeation rate derived in step (E) into I = f (v).

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Material>
X-ray contrast agent for resin 1: X-ray contrast agent for iodobenzene resin 2: Bromotoluene resin composition 1: Polyacetal resin composition (manufactured by Polyplastics, “Duracon (registered trademark) M90-44”)
Resin composition 2: Polyacetal resin composition containing 25% by mass of glass fiber (manufactured by Polyplastics, “Duracon (registered trademark) GH-25”)
Resin composition 3: Polybutylene terephthalate resin composition (Wintech Polymer Co., Ltd., “Duranex (registered trademark) 2002”)
Resin composition 4: Polybutylene terephthalate resin composition containing 30% by mass of glass fiber (manufactured by Wintech Polymer, "Duranex (registered trademark) 3300")
Resin composition 5: Polyphenylene sulfide resin composition (manufactured by Polyplastics, “Fortron (registered trademark) 0220A9”)
Resin composition 6: Polyphenylene sulfide resin composition containing 30% by mass of glass fiber (manufactured by Polyplastics, “Fortron (registered trademark) 1130A1”)
Resin composition 7: Polyphenylene sulfide resin composition containing 65% by mass of glass fiber and inorganic filler (manufactured by Polyplastics, “Fortron (registered trademark) 6165A61”)

<Resin molding>
Using each of the resin compositions 1 to 7 as a raw material, a resin molded body was produced by an injection molding method under general condition settings. Samples 1 to 7 as shown in FIG. 5 were cut out from the above resin molded bodies. The sample dimensions are 13 mm × 4.5 mm × 3.2 mm as shown in FIG. The “mold contact surface” in FIG. 5 refers to a portion that has been in contact with the mold at the time of injection molding. In addition, the “cut-out surface” refers to a portion formed by cutting out a sample.

<Evaluation of X-ray contrast agent for resin>
The initial weight of samples 1-7 was measured. After measuring the initial weight, Samples 1 to 7 were placed in a metal pressure vessel together with iodobenzene. Samples 1 to 7 were placed in a metal pressure vessel at 80 ° C., and then temporarily removed to measure the weight of the sample. FIG. 6 shows the relationship between the increased weight (%) when the initial weight is 100% and the time after the sample is put into the metal pressure vessel.

  Samples 2, 4, and 6 composed of resin compositions 2, 4, and 6 were placed in a 70 ° C. metal pressure vessel together with bromotoluene after initial weight measurement. Thereafter, the sample was temporarily removed from the metal pressure vessel and the weight was measured. FIG. 7A shows the relationship between the increased weight (%) when the initial weight is 100% and the time after the sample is put into the metal pressure vessel. Further, the same measurement was performed by changing bromotoluene to iodobenzene. The measurement results are shown in FIG.

  6 and 7, it was confirmed that at a temperature of 70 ° C. to 80 ° C., when the above-mentioned type of resin composition is a raw material, both iodobenzene and bromobenzene penetrate into the resin molded body.

  Moreover, it was confirmed from FIG. 6 that the X-ray contrast agent for resin hardly penetrates into the resin molded body by including glass fiber.

  Moreover, from FIG. 6, FIG.7 (b), it was confirmed that the ease of osmosis | permeation to the resin molding of the X-ray contrast agent for resin differs by different temperature conditions.

  Further, from the comparison between FIGS. 7A and 7B, it was confirmed that, under the above-mentioned conditions, iodobenzene penetrates the resin molded body more easily than bromotoluene.

<Detection of structural changes>
The initial weight of sample 6 (mold temperature 140 ° C.) and sample 6 ′ molded at a mold temperature of 60 ° C. were measured. Next, the sample was placed in an 80 ° C. metal pressure vessel together with iodobenzene. Subsequently, the sample was temporarily taken out from the metal pressure vessel at 3 hours, 6 hours, 9 hours, and 12 hours, and weight measurement and X-ray transmission image acquisition were performed. Acquisition of an X-ray transmission image was performed by the following method. In addition, the X-ray transmission image of the cross section orthogonal to a metal mold | die contact surface was acquired.
(Acquisition of X-ray transmission image)
A commercially available X-ray CT apparatus (ELE SCAN mini manufactured by Nippon Steel Elex Co., Ltd.) was used as the imaging apparatus. The resin test piece was placed on a sample stage of an X-ray CT apparatus and photographed by a regular method.

  FIG. 8A shows the relationship between the increased weight (%) when the initial weight is 100% and the time after the sample is put into the metal pressure vessel. FIG. 8B shows the relationship between the penetration distance obtained from the X-ray transmission image and the above time.

  From FIG. 8B, a decrease in the permeation rate was confirmed. Therefore, it was confirmed that there is a structural change of the resin molded body within a depth of about 180 μm from the mold contact surface.

<Determination of internal structure>
The change in crystallinity at each penetration distance shown in FIG. 8B was measured by the following method.
(Measuring method)
Using each sample, a thin film having a thickness of 20 μm was cut out from the surface layer of each sample with a microtome, and an IR spectrum was measured using a transmission type FT-IR apparatus. Crystallinity peaks around 1074cm ^-1 in the IR spectrum (peak derived from the amorphous component) was calculated from the intensity ratio of 1093Cm ^-1 near the peak (peak derived from the crystalline component) (1093/1074) . FIG. 9 (a) shows the result when using a resin molded body molded under the condition that the mold temperature is 60 ° C., and the result when using the resin molded body molded under the condition where the mold temperature is 140 ° C. This is shown in FIG.

  From the relationship between the peak intensity ratio of the FT-IR spectrum of FIG. 9A and the depth of the measurement site, it was confirmed that the crystallinity greatly changed between 140 μm and 220 μm. From the relationship between the peak intensity ratio of the FT-IR spectrum of FIG. 9B and the depth of the measurement location, it was confirmed that no change in crystallinity was observed. Based on the results of FIGS. 8 and 9, based on the penetration behavior of the resin X-ray contrast agent into the resin molding, it is possible to confirm the change in the internal structure or determine the internal structure using the crystallinity as an index. Was confirmed.

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 11 X-ray irradiation part 12 X-ray detection part 13 Sample stand 14 Rotation drive part 15 Image processing part 2 Resin molding

Claims (11)

An X-ray contrast agent for resin for infiltrating into a resin molded body and analyzing the internal structure of the resin molded body,
The X-ray contrast agent for resin comprised from the hydrocarbon type compound which has a mass absorption coefficient higher than the mass absorption coefficient of resin which comprises the said resin molding.   The X-ray contrast agent for resin according to claim 1, wherein the hydrocarbon compound is a halogenated hydrocarbon compound.   The X-ray contrast agent for resin according to claim 2, wherein the hydrocarbon compound is a halogenated aromatic hydrocarbon compound.   The X-ray contrast medium for resin according to claim 3, wherein the hydrocarbon compound is a compound containing either iodine or bromine.   The X-ray contrast agent for resin according to claim 4, wherein the hydrocarbon compound is either iodobenzene or bromotoluene. The resin X-ray contrast agent according to any one of claims 1 to 5 is permeated into a resin molded body,
From the X-ray transmission image corresponding to the cross section of the resin molded body, taken under conditions of two or more penetration times, the penetration speed for each depth in the direction in which the X-ray contrast agent for resin penetrates is derived,
A structure change detection method for detecting a change in an internal structure of the resin molded body based on a change in the penetration rate.   The structural change detection method according to claim 6, wherein the X-ray transmission image is an X-ray CT image.   The structure change detection method according to claim 6 or 7, wherein the resin molded body is made of a crystalline thermoplastic resin. The resin X-ray contrast agent according to any one of claims 1 to 5 is permeated into a resin molded body,
From the X-ray transmission image corresponding to the cross section of the resin molded body, taken under conditions of two or more penetration times, the penetration speed for each depth in the direction in which the X-ray contrast agent for resin penetrates is derived,
By analyzing the information on the internal structure of the resin molded body for each penetration rate, the relationship between the penetration rate and the internal structure is derived,
The resin X-ray contrast agent used for deriving the relationship is infiltrated into an analytical resin molded body composed of the same resin as the resin constituting the resin molded body,
From the X-ray transmission image of the analytical resin molded article taken under the condition of two or more penetration times, the penetration speed for each depth in the direction in which the resin X-ray contrast agent penetrates is derived,
An internal structure determination method for determining an internal structure of the analytical resin molding based on the permeation rate and the relationship.   The internal structure determination method according to claim 9, wherein the X-ray transmission image is an X-ray CT image. The resin molded body is composed of a crystalline thermoplastic resin,
The internal structure determination method according to claim 10, wherein the information related to the internal structure is a degree of crystallization of the analytical resin molded body or an orientation degree of the analytical resin molded body for each depth.

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