WO2023191051A1

WO2023191051A1 - Resin product with information code

Info

Publication number: WO2023191051A1
Application number: PCT/JP2023/013561
Authority: WO
Inventors: 真悟花岡; 宏樹村田; 英秋佐藤
Original assignee: 大塚テクノ株式会社
Priority date: 2022-04-01
Filing date: 2023-03-31
Publication date: 2023-10-05

Abstract

The present invention provides a resin product comprising a wall. The wall has a code area including a plurality of machined areas where protrusions and recesses are formed, and a transparent unmachined area, adjacent to the machined areas, where the protrusions and recesses are not formed. The reflectance of light in the machined areas is higher than the reflectance of light in the unmachined area, and the code area shows an optically readable information code.

Description

Resin products with information code

The present disclosure relates to a resin product on which an information code is displayed.

Patent Document 1 discloses a technique for printing a design on the main body of a PET bottle container by laser printing. The design is an identification mark for recycling, such as "PET" or "Plastic", which is required to be displayed under the Law for Promotion of Effective Utilization of Resources. According to Patent Document 1, in a PET bottle container on which such an identification mark is laser printed, there is no need to use an ink component for printing, so that recyclability is improved.

Further, Patent Document 2 discloses a PET bottle in which necessary information such as a name is directly engraved and printed on the bottle. Stamp printing can be performed, for example, by thermal processing or molding. This eliminates the need to separately attach a label to the PET bottle, providing a PET bottle with high recyclability.

JP2021-017248A Japanese Patent Application Publication No. 2011-011819

According to the techniques disclosed in Patent Documents 1 and 2, it is possible to display designs, characters, etc. on the PET bottle body without using external labels or ink components. However, the patterns, characters, etc. illustrated in Patent Documents 1 and 2 are for human viewing. In addition to this information, PET bottles distributed in the general market are provided with an information code that is optically read by a machine, but Patent Documents 1 and 2 do not take this into account. In this way, a PET bottle that does not require an external label or ink component and has an optically readable information code displayed on it has not been provided to date. This applies not only to PET bottles but also to highly transparent resin products.

The present disclosure aims to provide a transparent resin product on which an optically readable information code is displayed.

The resin product according to the first aspect of the present disclosure includes a wall portion. The wall portion has a code region including a plurality of processed regions in which unevenness is formed and a transparent unprocessed region adjacent to the processed region and in which the unevenness is not formed. The light reflectance of the processed area is higher than the light reflectance of the non-processed area, and the code area displays an optically readable information code.

According to the resin product according to the first aspect, the wall portion of the resin product itself displays an optically readable information code due to the processed areas having mutually different light reflectances and the transparent non-processed areas. That is, in order to display the information code, it is not necessary to attach ink components to the wall or to include additives that cause discoloration due to heat processing in the resin raw material. The resin product according to the first aspect can also be applied to cases where the use of the above-mentioned ink components and additives is restricted, such as containers for foods, beverages, and medicines.

Furthermore, according to the resin product according to the first aspect, there is no need to separately attach a label or sticker with an information code written thereon, and the process and resources for manufacturing these can be saved. Furthermore, the resin constituting the resin product can be easily recycled.

A resin product according to a second aspect of the present disclosure is a resin product according to the first aspect, wherein the information code is a barcode, the processing area corresponds to a space, and the non-processing area is a barcode. corresponds to

The resin product according to the third aspect of the present disclosure is the resin product according to the first aspect or the second aspect, and the maximum reflectance R _max of the processed area and the non-resin product measured using a code verification machine. The difference from the minimum reflectance R _min of the processing area is 20% or more.

A resin product according to a fourth aspect of the present disclosure is a resin product according to any one of the first to third aspects, and the unevenness includes regularly arranged concave portions and convex portions. In a length range of 200 μm along the arrangement direction of the concave portions and the convex portions, a height difference between at least one pair of adjacent concave portions and the convex portions is 5 μm or more and 50 μm or less.

A resin product according to a fifth aspect of the present disclosure is a resin product according to the fourth aspect, wherein the unevenness has a height difference within a length range of 200 μm along the arrangement direction of the concave portion and the convex portion. It includes four or more pairs of adjacent concave portions and convex portions each having a diameter of 5 μm or more and 50 μm or less.

A resin product according to a sixth aspect of the present disclosure is a resin product according to any one of the first to fifth aspects, and the unevenness includes irregularly arranged concave portions and convex portions.

A resin product according to a seventh aspect of the present disclosure is a resin product according to the sixth aspect, and the surface roughness of the processed area is 1.5 μm or more.

A resin product according to an eighth aspect of the present disclosure is a resin product according to any one of the first to seventh aspects, and is a container made of polyethylene terephthalate.

A method for manufacturing a resin product with an information code according to a ninth aspect of the present disclosure includes the following (1) and (2).
(1) Prepare a resin product with a transparent wall.
(2) Forming a code region on the wall portion including a plurality of processing regions in which unevenness is formed and a transparent non-processing region adjacent to the processing region and in which the unevenness is not formed.
Note that forming the code area means forming the unevenness so that the light reflectance of the processed area is higher than the light reflectance of the non-processed area, thereby making it optically readable. The purpose is to form a code area for displaying an information code.

A method of manufacturing a resin product with an information cord according to a tenth aspect of the present disclosure is a method of manufacturing a resin product with an information cord according to the ninth aspect, wherein (2) forming the code region includes The method includes forming the plurality of processing areas by irradiating the laser beam with a laser beam and forming the unevenness by laser marks.

A method of manufacturing a resin product with an information code according to an eleventh aspect of the present disclosure is a method of manufacturing a resin product with an information code according to the tenth aspect, in which forming the plurality of processing areas includes using the laser beam. , including pulse-by-pulse irradiation along a predetermined scan line.

A method for manufacturing a resin product with an information code according to a twelfth aspect of the present disclosure is a method for manufacturing a resin product with an information code according to the tenth aspect, in which the laser light has a wavelength in the ultraviolet region.

A method for manufacturing a resin product with an information code according to a thirteenth aspect of the present disclosure is a method for manufacturing a resin product with an information code according to the twelfth aspect, wherein forming the plurality of processing areas includes The method includes irradiating the wall portion with a laser beam that has passed through a photomask on which a pattern is formed, and the pattern has a shielding area that blocks the laser beam and a transmitting area that transmits the laser beam.

A method of manufacturing a resin product with an information code according to a fourteenth aspect of the present disclosure is a method of manufacturing a resin product with an information code according to the ninth aspect, in which (2) forming the code region includes the following ( 3) Contains (4).
(3) Covering the surface of the wall portion except for portions that are to become the plurality of processing areas with a mask.
(4) Colliding particles against the wall portion covered with the mask to form the unevenness due to impact marks of the particles in areas not covered with the mask.

A method for manufacturing a resin product with an information code according to a fifteenth aspect of the present disclosure includes the following.
・Prepare transparent resin material.
- A mold for molding the resin material to produce a resin product having a wall portion, the mold having a plurality of first regions in which unevenness is formed, and adjacent to the first region and in which the unevenness is formed. preparing a mold including a cavity surface formed with a second region where the cavity surface is not stained;
- Molding the transparent resin material using the mold.
- A code area is formed from the mold, including a plurality of processed areas to which the unevenness of the plurality of first areas is transferred, and a non-processed area adjacent to the processed area and in which the unevenness is not formed. Take out a resin product with a wall section.
Note that the light reflectance of the processed area is higher than the light reflectance of the non-processed area, and the code area displays an optically readable information code.

According to the present disclosure, an optically readable information code is displayed by the processed area and the transparent non-processed area formed on the wall of the resin product. Thereby, it is possible to provide a resin product on which an information code is displayed without causing ink components to adhere to the wall.

FIG. 1 is an overall view of a resin product according to an embodiment. An image representing an example of a code region according to an embodiment. FIG. 3 is a diagram illustrating a code region evaluation method. A micrograph of a processed area formed by laser light irradiation. A microscopic photograph of the processed area formed by shot blasting. Micrograph of another processed area formed by laser light irradiation. 2 is a flowchart showing steps of a method for forming a processing area using laser light. FIG. 2 is a schematic diagram showing the configuration of a laser beam irradiation device. 5 is a flowchart showing steps of a method for forming a processing area by shot blasting. FIG. 3 is a diagram illustrating a method of forming a processing area by shot blasting. 7 is a flowchart showing the steps of another method for forming a processing area using a laser beam. FIG. 3 is a schematic diagram showing the configuration of another laser beam irradiation device. 5 is a flowchart showing steps of a method for forming a processing area by molding. FIG. 3 is a diagram illustrating a method of forming a processing area by molding. Photo of existing barcode for comparison. Waveform obtained by reading an existing barcode using a code verification machine. 1 is a micrograph of a processing area according to Example 1. A waveform obtained by reading a code region according to Example 1 using a code verifier. A micrograph of a processed area according to Reference Example 1. A waveform obtained by reading the code area according to Reference Example 1 using a code verification machine. The height profile of the processing area according to Example 1. The height profile of the processing area according to Example 2. A waveform obtained by reading a code region according to Example 5 using a code verifier. A micrograph of a processed area according to Reference Example 2. A waveform obtained by reading a code region according to Reference Example 2 using a code verification machine. FIG. 7 is a diagram showing a pattern of a photomask according to Example 9. FIG. 7 is a diagram showing a pattern of a photomask according to Example 10. FIG. 7 is a diagram showing a pattern of a photomask according to Example 11. A micrograph of a processing area according to Example 9. A micrograph of a processing area according to Example 10. A micrograph of a processing area according to Example 11. A waveform obtained by reading a code region according to Example 9 using a code verifier. A waveform obtained by reading a code region according to Example 10 using a code verifier. A waveform obtained by reading a code region according to Example 11 using a code verifier.

Hereinafter, a resin product according to an embodiment of the present disclosure will be described with reference to the drawings.

<1. Overall composition of resin products>
FIG. 1 is an overall view of a resin product 1 according to an embodiment of the present disclosure. Although not limited thereto, in this embodiment, the resin product 1 is a container made of polyethylene terephthalate (PET), and is colorless and transparent except for processing areas 40 and 40a, which will be described later. The resin product 1 is typically configured as a plastic bottle for accommodating contents such as beverages and seasonings. Although the following description will be made with reference to the vertical direction in FIG. 1, the direction in which the resin product 1 is used is not limited to this.

The resin product 1 includes a wall portion 2. The wall part 2 constitutes an integrally formed bottom part 20, side wall part 21 and mouth part 22, thereby defining a space for accommodating the contents. The bottom part 20 is configured so that the PET bottle can stand on its own by being placed facing downward on a flat surface. The side wall portion 21 is a cylindrical portion that rises from the bottom surface portion 20, and is continuous with the substantially cylindrical mouth portion 22 at the top. Mouth 22 defines an opening for removal of contents. Furthermore, a thread is integrally formed on the outer surface of the mouth portion 22, so that a cap formed separately from the resin product 1 can be attached thereto.

<2. Code area>
FIG. 2 is an image illustrating the code area 4. As shown in FIG. The code region 4 is a virtual region that circumscribes a plurality of processed regions 40 formed on the outer surface 3 of the wall portion 2 and a plurality of non-processed regions 41 adjacent thereto. The processing areas 40 are white rectangular areas each having a longitudinal direction and a lateral direction, and in this embodiment, the processing areas 40 are arranged so that the longitudinal direction runs along the vertical direction of the resin product 1. As will be described later, the processed area 40 is made up of finely formed unevenness, and the unevenness reflects light diffusely, so that the processed area 40 has a higher light reflectance than the non-processed area 41. In addition, in the drawing, only the representative ones among the plurality of processed areas 40 and non-processed areas 41 are labeled with reference numerals.

The plurality of unprocessed regions 41 are unprocessed regions (in which no unevenness is formed) left between the plurality of processing regions 40, and are formed by the code region 4 into a plurality of regions having a longitudinal direction and a transverse direction. As a rectangular area, it is virtually distinguished from the surrounding parts of the code area 4. Although the unprocessed area 41 appears blacker than the processed area 40 in FIG. 2, it is actually colorless and transparent, hardly reflects light, and has a lower light reflectance than the processed area 40. Due to the contrast in reflectance between the processed area 40 and the non-processed area 41, an information code C that can be optically read by a device such as a code reader can be displayed. Hereinafter, the direction in which the plurality of processed regions 40 and the plurality of non-processed regions 41 are arranged will be referred to as the horizontal direction of the code region 4, and the direction perpendicular to the horizontal direction will be referred to as the vertical direction of the code region 4.

The information code C is a one-dimensional code in this embodiment, although it is not limited thereto. More specifically, the information code C is a barcode ( (see FIG. 13A). The plurality of processed areas 40 have a reflectance corresponding to the white part of the information code C, and the plurality of non-processed areas 41 have a reflectance corresponding to the black part of the information code C. That is, among the plurality of processing areas 40, those located at both ends of the code area 4 in the lateral direction correspond to the quiet zones, and the other areas correspond to the spaces of the information code C, respectively. Further, the plurality of non-processing areas 41 correspond to the bars of information code C, respectively.

The widths of the plurality of processed areas 40 and the plurality of non-processed areas 41 in the lateral direction may be different depending on the space included in the information code C and the specified width of the bar. The specified widths of the spaces and bars may have two or more levels, three or more levels, or four or more levels, depending on the standard that the information code C follows.

The wall portion 2 may further include a processing area 40a apart from the code area 4. The processing area 40a is an area where elements other than the quiet zone, bar, and space of the information code C, such as characters and figures, are displayed using unevenness similar to the processing area 40. In the example of FIG. 2, a plurality of processing areas 40a representing numbers corresponding to the information code C are formed below the code area 4. This number can be read by the human eye.

<3. Reflectance of code area＞
The quality provided for the code area 4 to be optically read as the information code C will be described below. As a type of code reader for reading the information code C, for example, a laser beam (including light reflected by a galvanometer mirror, etc.) is irradiated along the horizontal direction of the code area 4, and a plurality of processed areas 40 and non-processed areas are used. One example is one in which reflected light sequentially reflected from 41 is detected by a light receiving element. The reflected light is detected as an analog waveform by the light receiving element, but by A/D converting this into a digital waveform, it can be converted into mechanically readable data. As a result, the information of the information code C is decoded in the code reader.

The quality for reading by a code reader is determined by using a code verifier 5 having an aperture size according to the type of information code C and the size of the code area 4, for example, according to ANSI X3.182 (hereinafter simply "ANSI (sometimes referred to as ")". The code verifier 5 irradiates the code with a laser beam of a predetermined wavelength and outputs the reflectance from the code in the reading direction of the code in an analog waveform (Scan Reflectance Profile: SRP). In this embodiment, the STRATIX Laser Xaminer Elite Series (manufactured by STRATIX, irradiation wavelength 650 nm) is used as the code verification device 5, and the quality of the information code displayed by the code area 4 is evaluated based on the SRP that will be output from now on. .

FIG. 3 is a diagram illustrating a method for evaluating the code region 4 according to the present embodiment. As shown in FIG. 3, the cord area 4 cut out from the wall 2 is fixed to the installation stand 6. More specifically, the code area 4 is fixed to the edge of the installation base 6 so that the vertical center of the code area 4, which is the reading point by the code verification device 5, protrudes outside the installation base 6, and the code area 4 is read. Make sure the entire area is well away from the floor or other objects. This eliminates the influence of the background on reading. Further, the code verifier 5 is arranged on the installation stand 6 so that it can read the vicinity of the longitudinal center of the code area 4 at a scanning angle of 45 degrees. In the above state, the code area 4 is read by the code verifier 5 and the SRP is output. Note that reading by the code verifier 5 may be performed multiple times while shifting the reading location in the vertical direction.

Evaluation indicators according to ANSI include minimum reflectance, symbol contrast SC, minimum edge contrast EC _min , modulation MOD, defect, and decodability V. Each indicator will be explained below.

[Minimum reflectance]
The minimum reflectance is an index for evaluating whether a sufficient margin is secured between the reflectance of the processed area 40 and the reflectance of the non-processed area 41. The maximum reflectance of the processed area 40 corresponding to the space specified from the above SRP is assumed to be R _max , and the minimum reflectance of the non-processed area 41 is assumed to be R _min . When R _max and R _min satisfy the following formula (1), a sufficient margin is secured between the reflectance of the processed area 40 and the reflectance of the non-processed area 41, and the quality as an information code is sufficient. (Grade A).
_Rmin ≦ _0.5Rmax (1)

[Symbol contrast]
The symbol contrast SC is an index for evaluating whether the contrast between the processed area 40 and the non-processed area 41 is sufficient, and in order to be evaluated as having sufficient quality as an information code, it must be 20% or more. It must be. Note that the larger the SC value, the better, and ANSI defines graded grades according to the SC value. SC can be calculated based on the above R _max and R _min according to the following equation (2).
SC= _Rmax - _Rmin (2)

[Minimum Edge Contrast]
The minimum edge contrast EC _min is an index for evaluating whether the contrast between the processed area 40 corresponding to the space and the non-processed area 41 adjacent thereto is sufficient, and the quality as an information code is sufficient. In order to be evaluated as (grade A), it needs to be 15% or more. The edge contrast EC can be calculated according to the following equation (3), where R _S is the reflectance of the processed area 40 corresponding to the space, and R _b is the reflectance of the non-processed area 41. EC _min is the minimum value of EC calculated according to equation (3).
EC=R _S -R _b (3)

[Modulation]
Modulation MOD can be calculated according to equation (4) below. In order to be evaluated as having sufficient quality as an information code, the MOD needs to be 40% or more. Note that the higher the MOD value, the better, and ANSI defines graded grades according to the MOD value.
MOD= _ECmin /SC (4)

[Defect]
The defect is an index for evaluating defects such as voids in bars and spots in spaces, and in the code region 4, corresponds to missing irregularities in the processing region 40. In order to be evaluated as having sufficient quality as an information code, the defect must be 0.30 or less. Note that the smaller the defect value, the better, and ANSI defines graded grades according to the defect value. The defect can be calculated according to the following equation (5), where ERN _max is the maximum variation in reflectance within one processed region 40 or non-processed region 41.
ERN _max /SC (5)

[Decodability]
The decodability V is an index for evaluating whether the width in the width direction of the processed area 40 or the width in the width direction of the non-processed area 41 corresponding to the space can be distinguished according to prescribed steps. In order to be evaluated as having sufficient quality as an information code, the decodability V needs to be 0.25 or more. Note that the larger the value of V, the better, and ANSI defines graded grades according to the value of V.

Up to now, no PET bottle has been provided with an information code that indicates that it is of sufficient quality based on the above-mentioned indicators. As a result of intensive studies, the inventor has determined that by forming fine irregularities on the wall portion 2, the transparency of the PET as a whole of the processing area 40 is lost, and an information code that is evaluated as having sufficient quality according to the above index is created. We have developed resin product 1 that displays the following. The processing area 40 according to this embodiment will be explained below.

<4. Processing area＞
4A, FIG. 4B, and FIG. 4C are examples of micrographs (magnifications of 1000, 100, and 3000, respectively) of the processing area 40 according to this embodiment. FIG. 4A shows an example of a processed region 40 in which unevenness is formed by laser marks for each pulse, and the unevenness is formed by regularly arranged concave portions 400 and convex portions 401. FIG. 4B is an example of a processed region 40 in which unevenness is formed by shot blasting, and unlike FIG. 4A, irregular unevenness is formed due to collision marks of particles. FIG. 4C is an example of a processing area 40 in which unevenness is formed by one shot of laser marks. Similar to FIG. 4A, the unevenness is formed by regularly arranged concave portions 400c and convex portions 401c. is more minute. Note that in the drawings, only typical ones among the plurality of recesses 400, 400c and the plurality of projections 401, 401c are labeled with reference numerals. Each will be explained below.

The recesses 400 shown in the micrograph of FIG. 4A are marks where the PET is depressed inward due to thermal deformation, and one recess 400 corresponds to one laser mark of one pulse. The convex portion 401 is a portion that is relatively outwardly convex so as to surround the concave portion 400, and is formed as the concave portion 400 is formed. By having such unevenness continuous vertically and horizontally, the processing area 40 as a whole can reflect light diffusely. The vertical and horizontal dimensions of the recesses 400 measured from a photomicrograph are approximately 20 μm to 30 μm, and the interval (pitch) between adjacent recesses 400 is approximately 20 μm to 30 μm.

The processing area 40 consists of at least one pair of adjacent recesses 400 and projections 401 with a height difference of 5 μm or more and 50 μm or less in a length range of 200 μm along the arrangement direction of the recesses 400 and projections 401. It is preferable to include four or more pairs of such recessed portions 400 and convex portions 401. The arrangement direction is a direction in which a portion of the convex portions 402 surrounding mutually adjacent concave portions 400 continues, and is the direction of the arrow shown in FIG. 4A. The height difference between the adjacent concave part 400 and convex part 401 is specified based on the height profile of a height measurement tool using a laser scan of a 3D measurement laser microscope (manufactured by OLYMPUS, LEXT OLS5000, objective lens 50 times). This is the difference between the average height of one concave portion 400 and the average height of adjacent convex portions 401. When the height difference is greater than or equal to the above lower limit, the light reflectance can be increased. In addition, since the height difference is less than or equal to the above upper limit, the strength required for the wall portion 2 can be maintained.

Furthermore, from the viewpoint of reducing variations in reflectance within the same processing region 40, it is preferable that the processing region 40 includes many pairs of concave portions 400 and convex portions 401 with height differences within the above range. Note that pairs including overlapping concave portions 400 or convex portions 401 are counted as different items. The laser beam conditions for forming such a processing area 40 will be described later.

On the other hand, when forming the unevenness of the processing area 40 as shown in FIG. From the viewpoint of ensuring this, the thickness is preferably 1.5 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more. Note that the surface roughness Ra refers to the surface roughness measured by an Ra measurement tool of a 3D measurement laser microscope (manufactured by OLYMPUS, LEXT OLS5000, objective lens 50 times). The shot blasting conditions for forming the processed region 40 having such surface roughness will be described later.

The recesses 400c and protrusions 401c shown in the micrograph of FIG. 4C are similar to the recesses 400 and protrusions 401 shown in the micrograph of FIG. 4A in that they are formed by laser marks. However, the concave portion 400c and the convex portion 401c are different from the concave portion 400 and the convex portion 401 in FIG. 4A in the wavelength of the laser beam used for formation and in the formation method. A method for forming the concave portion 400c and the convex portion 401c will be described later.

Similar to the example in FIG. 4A, the recess 400c is a mark where the PET is depressed inward due to thermal deformation. On the other hand, the convex portion 401c is a relatively outwardly convex portion so as to surround the concave portion 400c. By having such unevenness continuous vertically and horizontally, the processing area 40 as a whole can reflect light diffusely. The vertical and horizontal dimensions of the recess 400c measured from the photomicrograph are approximately 4.5 μm to 7 μm, depending on the shape of the recess 400c. Further, the minimum width of the convex portion 401c measured from a photomicrograph is approximately 0.3 μm to 1 μm, although it depends on the shape of the convex portion 401c.

The average height difference between a pair of adjacent concave portions 400c and convex portions 401c measured based on the height profile of the height measurement tool using the laser scan is approximately 3.5 μm to 5.5 μm. The average value is the average value of the height differences between three different pairs of adjacent concave portions 400c and convex portions 401c randomly extracted from the processing area 40.

<5. Method of forming processing area>
Hereinafter, a method for manufacturing the resin product 1, including a method for forming the processing area 40 described above, will be described.

[Formation method using continuous laser light irradiation]
FIG. 5 is a flowchart showing the steps of a method for manufacturing a resin product 1 in which a processing area 40 is formed by continuous irradiation with laser light. Moreover, FIG. 6 is a schematic diagram showing an example of the laser light irradiation device 7 used in this method. As the laser beam irradiation device 7 shown in FIG. 6, a known device such as a gas laser, solid laser, liquid laser, or semiconductor laser can be used. As shown in FIG. 6, the laser beam irradiation device 7 includes a table 70 on which a target product to be laser irradiated is placed and an xy stage 71, and the table 70 can be moved in a plane direction by the xy stage 71. . The laser beam irradiation device 7 further includes a galvano scanner 74 to which a laser oscillator 72, a beam expander 73, and an Fθ lens 75 are connected. The laser beam irradiation device 7 adjusts the spread angle of the laser beam generated by the laser oscillator 72 with a beam expander 73, and further controls the irradiation position of the laser beam with a galvano scanner 74, so as to leave a laser mark on the surface of the target product. Form.

Referring again to FIG. 5, in step S1, the resin product 10 on which the code region 4 is to be formed is prepared. The resin product 10 only needs to have a wall portion 2a for forming the code region 4, and in this embodiment, it is a colorless and transparent PET bottle.

In step S2, the resin product 10 is set in the laser light irradiation device 7. More specifically, the resin product 10 is fixed on the table 70, and positioned using the xy stage 71 so that the laser beam is irradiated onto the portion of the wall portion 2a where the code region 4 is to be formed.

In step S3, the resin product 10 is irradiated with laser light by the laser light irradiation device 7, and unevenness by laser marks is continuously formed one by one on the wall portion 2a of the resin product 10. The laser light irradiation device is set in advance to continuously irradiate laser light for each pulse along a predetermined scanning line. Normally, to form one processing area 40, continuous irradiation of laser light along a plurality of scanning lines is performed. Therefore, when continuous irradiation is performed along a predetermined number of scanning lines corresponding to the quiet zone and space of information code C, a processing area 40 corresponding to the quiet zone and space is formed. Although the conditions of the laser beam are not limited to these, for example, the spot diameter is 30 μm, the frequency is 100 kHz, and the average output is 4 W. Further, the scanning speed of the laser beam is 2000 mm/s to 3000 mm/s, and when the scanning speed is 2000 mm/s, the line pitch is preferably 25 μm to 30 μm, and when the scan speed is 3000 mm/s, the line pitch is preferably 25 μm to 30 μm. The line pitch is preferably 20 μm to 25 μm.

In step S3, when all the processing areas 40 corresponding to the quiet zones and spaces of the information code C are formed, the resin product 1 in which the code area 4 is formed on the wall portion 2 is obtained.

[Formation method by shot blasting]
FIG. 7 is a flowchart showing steps of a method for manufacturing a resin product 1 in which a processing area 40 is formed by shot blasting. Further, FIG. 8 is a diagram illustrating a method of shot blasting. As shown in FIG. 8, in shot blasting, a metal mask 11 with openings formed in positions corresponding to the quiet zone and space of the information code C is prepared in advance.

Referring again to FIG. 7, in step S11, the resin product 10 on which the code region 4 is to be formed is prepared. The resin product 10 only needs to have a wall portion 2a for forming the code region 4, and in this embodiment, it is a colorless and transparent PET bottle.

In step S12, the surface of the wall portion 2a of the resin product 10 is covered with the metal mask 11 described above. That is, in step S12, the surface of the wall portion 2a of the resin product 10 excluding the portions that are to become the plurality of processing areas 40 is covered with the metal mask 11.

In step S13, shot blasting is performed on the wall portion 2a of the resin product 10 covered with the metal mask 11. As a result, the surface of the wall portion 2a of the resin product 10 exposed through the opening of the metal mask 11, that is, the area not covered by the metal mask 11, is formed with unevenness due to collision traces of particles, and the information code C quiet Processing areas 40 corresponding to zones and spaces are formed. No particle collision marks are formed in the portion covered by the metal mask 11, which becomes an unprocessed region 41.

In step S14, when the metal mask 11 is removed from the resin product 10, the resin product 1 in which the code region 4 is formed on the wall portion 2 is obtained.

Particles used in shot blasting are not limited to these, but particles with a size of 30 μm to 50 μm made of natural ore with a Vickers hardness of 3000 Hv can be used. Further, the blasting time can be set to 2 seconds, for example. The pistol pressure, which is the air pressure at which the particles are blown, is preferably 0.8 Bar or more, more preferably 1 Bar or more, and even more preferably 3 Bar or more.

[Formation method using wide area irradiation of laser light]
FIG. 9 is a flowchart showing the steps of a method for manufacturing a resin product 1 in which a processing area 40 is formed by wide-area irradiation with laser light. Moreover, FIG. 10 is a schematic diagram showing an example of the laser light irradiation device 8 used in this method. In this method, a laser beam irradiation device 8 irradiates a UV laser having a wavelength in the ultraviolet region. The wavelength of the UV laser is not particularly limited, and is, for example, 355 nm, 308 nm, or 266 nm.

The laser light irradiation device 8 may be either a gas UV laser device or a solid UV laser device. As shown in FIG. 10, the laser beam irradiation device 8 includes a table 80 on which a target product to be laser irradiated is placed. The laser beam irradiation device 8 further includes a laser oscillator 82, a projection lens 83, a mirror 84, and a condenser lens 85. A photomask 81 is placed between the projection lens 83 and the mirror 84.

The photomask 81 is a photomask on which a fine pattern representing the information code C is formed. The photomask 81 according to this embodiment includes a synthetic quartz substrate and a chromium film laminated on one side of the substrate. As shown in FIG. 10, the chromium film forms a grid-like shielding region 810. On the other hand, a plurality of rectangular regions of the synthetic quartz on which the chromium film is not formed form transmission regions 811 through which laser light is transmitted. In the drawing, only representative ones among the plurality of transparent regions 811 are labeled. The laser beam transmitted through the transmission region 811 forms the recess 400c, and along with this, the recess 401c is also formed.

The laser beam irradiation device 8 adjusts the spread angle of the laser beam generated by the laser oscillator 82 using the projection lens 83. The adjusted laser light becomes a predetermined beam shape by passing through the photomask 81. The laser beam is further changed in its traveling direction by a mirror 84 and enters a condenser lens 85 . The laser beam that has passed through the condensing lens 85 is focused on the surface of the target product of the photomask 81. This creates laser marks on the surface of the target product.

Referring again to FIG. 9, in step S21, the resin product 10 on which the code region 4 is to be formed is prepared. The resin product 10 only needs to have a wall portion 2a for forming the code region 4, and in this embodiment, it is a colorless and transparent PET bottle.

In step S22, the photomask 81 is placed between the projection lens 83 and mirror 84 of the laser beam irradiation device 8.

In step S23, the resin product 10 is set in the laser light irradiation device 8. More specifically, the resin product 10 is fixed on the table 80, and the resin product 10 is positioned so that the laser beam is irradiated onto the portion of the wall portion 2a where the code region 4 is to be formed.

In step S24, the resin product 10 is irradiated with laser light by the laser light irradiation device 8 to form unevenness by laser marks on the wall portion 2a of the resin product 10. In this method, since the beam shape of the laser light is shaped by the photomask 81, the plurality of recesses 400c are formed by one pulse of laser light. The energy density of the laser beam is, for example, 500 mJ/cm ² , although it is not limited thereto.

In step S24, when all the processing areas 40 corresponding to the quiet zones and spaces of the information code C are formed, the resin product 1 in which the code area 4 is formed on the wall portion 2 is obtained.

<6. Features＞
(1) According to the resin product 1 according to the above embodiment, the information code C is displayed by physically processing the wall portion 2 of the resin product 1 without requiring labels, stickers, or other accessories that are configured separately. can do. Thereby, the consumption of resources for displaying the information code C can be suppressed, and distribution management of the resin products 1 (including those containing contents) is also facilitated.

(2) According to the resin product 1 according to the above embodiment, there is no need to mix additives for laser marking into the raw material, and there is no need to attach ink to improve code readability. This facilitates recycling and prevents unintended coloring from occurring in the recycled pellets.

(3) According to the method of irradiating a wide area with laser light using UV laser light and the photomask 81, the code area 4 is formed in a shorter time than the method of continuously irradiating laser light along the scanning line. can do. For example, the duration of UV laser light irradiation is 20 nanoseconds per shot. On the other hand, it takes about 5 seconds to continuously irradiate the laser beam to form the recesses 400 one by one to form the code area 4 showing the barcode as shown in FIG. 13A. Depending on the output of the laser beam irradiation device 8, it is possible to form code regions 4 of the same size indicating the same barcode in one shot.

<7. Modified example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit thereof. For example, the following changes are possible: Furthermore, the gist of the following modifications can be combined as appropriate.

(1) In the above embodiment, the processed region 40 was formed by laser irradiation or shot blasting. However, the method for forming the processing area 40 is not limited to this, and for example, when molding the resin product 1 using a mold, a wall portion with unevenness formed therein can be integrally formed as the processing area 40. FIG. 11 is a flowchart showing the steps of a method for molding the resin product 1 using a mold, and FIG. 12 is an example of the mold 12 used in this method. Although not limited thereto, the mold 12 has two molds that can be opened and closed, and when these molds are closed, a cavity having a shape corresponding to the wall portion 2 of the resin product 1 is formed. On the cavity surface of the mold 12, there are formed a plurality of first regions 120 in which fine irregularities are formed, and a second region 121 adjacent to the first regions 120 and in which no irregularities are formed. The plurality of first regions 120 have a shape in which the quiet zone and space of the information code C are inverted as a whole. Note that in the drawings, only representative ones among the plurality of first regions 120 are labeled with reference numerals.

Referring again to FIG. 11, in step S31, the resin material 13 (see FIG. 12) of the resin product 1 is prepared. In this embodiment, the resin material 13 is transparent and colorless PET.

In step S32, the resin material 13 is molded using the mold 12. The method for molding the resin material 13 is not particularly limited, and any known method can be used. At the same time as the resin material 13 is molded, the unevenness of the first region 120 is transferred to the outer surface of the wall portion, and a plurality of processed regions 40 are formed. Therefore, it is preferable that the irregularities in the first region 120 have a density, size, and surface roughness close to those caused by laser marks caused by the laser beam irradiation or particle marks caused by the shot blasting process.

In step S33, the mold 12 is opened and the molded resin product 1 is taken out. As a result, a wall is formed with a code region 4 including a plurality of processing regions 40 to which the unevenness of the plurality of first regions 120 has been transferred, and a non-processing region 41 adjacent to the processing region and in which no unevenness is formed. A resin product 1 comprising a portion 2 is obtained.

(2) In the above embodiment, the resin product 1 was colorless and transparent. However, the resin product 1 may be translucent or opaque, or may be colored.

(3) In the above embodiment, the resin product 1 was made of PET. However, the material of the resin product 1 is not particularly limited, and may be made of other resins. The resin constituting the resin product 1 is not particularly limited as long as it can be processed by laser irradiation, blasting, or molding as described above.

(4) In the above embodiment, the information code C was a one-dimensional barcode. However, the information code C may be a one-dimensional code other than a barcode, or may be a two-dimensional code. Further, in the resin product 1, the part where the code region 4 is formed and the direction of the code region 4 with respect to the resin product 1 are not particularly limited, and can be selected as appropriate.

(5) Step S22 of the method shown in FIG. 9 may be performed before step S21 or after step S23. Further, the pattern of the photomask is not limited to that of the above embodiment. For example, as shown in the following embodiments, a pattern may be formed in which predetermined figures are two-dimensionally arranged along a first direction and a direction orthogonal to the first direction.

Examples will be described below. The following examples are merely illustrative, and the present disclosure is not limited to the following examples.

<Experiment 1>
The outer surface of a colorless and transparent PET bottle is irradiated with laser light (semiconductor laser light) using a device as shown in Figure 6 to form a processing area containing fine irregularities, thereby creating an area similar to the existing one shown in Figure 13A. A resin product was produced in which a code area representing a barcode was formed. Existing barcodes were displayed on known resin films (labels) of PET bottles using known printing methods. Moreover, FIG. 13B shows the SRP when the barcode shown in FIG. 13A is read by the above code verification machine (STRATIX Laser Xaminer Elite Series). The laser light irradiation conditions were set to five as shown in Table 1 below, and the resin products corresponding to each condition were used as the resin products of Examples 1 to 4 and Reference Example 1, respectively.

A code area is cut out from the wall of the resin product according to Examples 1 to 4 and Reference Example 1, and read by the above code verification machine according to the method shown in FIG. 3. Based on the output SRP, the above ANSI evaluation index is determined. were calculated respectively. As a result, for all code regions, the indicators other than symbol contrast SC were grade A or B as defined by ANSI. Therefore, Table 2 below shows the results of symbol contrast SC. As shown in Table 2, in Examples 1 to 4 except Reference Example 1, the SC was 20% or more.

For reference, a micrograph (magnification: 1000) of the processing area according to Example 1 is shown in FIG. 14A, SRP is shown in FIG. 14B, and a micrograph (magnification: 1000) of the processing area according to Reference Example 1 is shown in FIG. is shown in FIG. 15B. As can be seen from these figures, in Example 1, the unevenness caused by laser marks was formed continuously and densely, whereas in Reference Example 1, the unevenness caused by laser marks was sparse compared to Example 1. Ta. In addition, the SRP of Example 1 is close to the SRP shown in FIG. 13B and has a higher reflectance in the processed area, whereas the SRP of Reference Example 1 is more reflective than the SRP of Example 1. rate has become lower.

For reference, the height profile of the processing area according to Example 1 and the height profile of the processing area according to Example 2 obtained by the 3D measurement laser microscope are shown in FIGS. 16A and 16B, respectively. These height profiles are height profiles at a length of 200 μm along the direction in which the laser marks are arranged in the processing area. As shown in FIG. 16A, the processing area according to Example 1 included five pairs of adjacent concave portions and convex portions with height differences of approximately 10 μm to 14 μm. Further, as shown in FIG. 16B, the processing area according to Example 2 included five pairs of adjacent concave portions and convex portions with a height difference of about 18 μm to 22 μm.

Through Experiment 1, it was confirmed that a resin product on which an optically readable information code was displayed could be provided by forming unevenness with laser marks.

<Experiment 2>
Shot blasting is applied to the outer surface of a colorless and transparent PET bottle using a metal mask as shown in FIG. 8 to form a processed area including fine irregularities, and a code area representing the barcode shown in FIG. 13A is formed. A resin product was produced using the following methods. The shot blasting conditions were set to five conditions as shown in Table 3 below, and the resin products corresponding to each condition were used as the resin products of Examples 5 to 8 and Reference Example 2, respectively. Particles with a size of 30 μm to 50 μm made of natural ore with a Vickers hardness of 3000 Hv were used as particles for shot blasting.

A code area is cut out from the wall of the resin product according to Examples 5 to 8 and Reference Example 2, and read by the code verification machine according to the method shown in FIG. 3. Based on the output SRP, the evaluation index according to the ANSI is determined. were calculated respectively. As a result, for the code regions according to Examples 5 to 8, the indicators other than symbol contrast SC were grade A or B as defined by ANSI. Therefore, Table 4 below shows the results of symbol contrast SC. Table 4 also shows the surface roughness Ra (μm) measured by the 3D measurement laser microscope. As shown in Table 4, in Examples 5 to 8, the SC was 20% or more. Although Reference Example 2 met the SC criteria, it did not meet the ANSI criteria for other evaluation indicators.

For reference, the SRP of the code region according to Example 5 is shown in FIG. 17, the micrograph (magnification 100) of the processed region according to Reference Example 2 is shown in FIG. 18A, and the SRP is shown in FIG. 18B. Note that the micrograph (magnification: 100) of the processed area according to Example 5 is the micrograph shown in FIG. 4B. As can be seen from these figures, in Example 5, relatively coarse unevenness was formed due to particle collision marks, whereas in Reference Example 2, compared to Example 5, unevenness due to particle collision was finer. It had become. In addition, the SRP of Example 5 is close to the SRP shown in FIG. 13B and has a higher reflectance in the processed area, whereas the SRP of Reference Example 2 is more reflective than the SRP of Example 5. rate has become lower. This is because the pistol pressure of the shot blasting conditions according to Reference Example 2 is low, and the surface roughness Ra is smaller in the processing area according to Reference Example 2 than in the processing areas according to other Examples 5 to 8. it is conceivable that.

<Experiment 3>
The outer surface of a colorless and transparent PET bottle is irradiated with UV laser light using a device such as that shown in Figure 10 to form a processing area that includes minute irregularities, and an existing barcode as shown in Figure 13A is created. A resin product in which a code region representing the expression was formed was fabricated. The wavelength of the UV laser was 308 nm, and the energy density was 500 mJ/cm ² . The apparatus is capable of processing a range of 2.5 mm x 1.0 mm per shot, and the code area was formed by irradiating the UV laser multiple times. Furthermore, quartz chrome photomasks with three patterns shown in FIGS. 19A to 19C were used, and the resin products corresponding to each photomask were the resin products of Examples 9 to 11, respectively. FIG. 19A shows a pattern in which two types of squares having different sizes are arranged along a first direction and a second direction perpendicular to the first direction. FIG. 19B shows a pattern in which regular hexagons are arranged along a first direction and a second direction perpendicular to the first direction. FIG. 19C shows a pattern in which squares are arranged along a first direction and a second direction perpendicular to the first direction. In the patterns shown in FIGS. 19A to 19C, the white areas are transparent areas and the black areas are shielded areas.

A code area was cut out from the wall of the resin product according to Examples 9 to 11, and read by the above code verification machine according to the method shown in FIG. 3. Based on the output SRP, the above ANSI evaluation index was calculated. . As a result, for the code regions according to Examples 9 to 11, the indicators other than symbol contrast SC were grade A or B as defined by ANSI. Therefore, Table 5 below shows the results of symbol contrast SC. As shown in Table 5, the SC of the resin products according to Examples 9 to 11 was all 20% or more. Further, the ANSI overall grade of the resin products according to Examples 9 to 11 was all D, demonstrating that they could be read by a scanner.

For reference, micrographs (magnification: 3000) of processed areas according to Examples 9 to 11 are shown in FIGS. 20A to 20C, respectively. As can be seen from these micrographs, the shapes of the recesses and projections formed on the wall of the resin product differ depending on the pattern of the photomask. In addition, in each micrograph, select a part where the machined surface is confirmed to be stable, and calculate the average value of lengths A to F measured from the boundaries of the bright and dark regions of the photograph as the recess dimension and length G. When the average value of ~L is taken as the minimum width of the convex portion, each value is as shown in Table 6 below. In addition, the average value of the difference in height between the concave portion and the convex portion measured at three different locations was selected as shown in Table 6 below. The height difference was measured based on the profile (length: 258.303 μm) of the 3D measurement laser microscope.

Furthermore, for reference, the SRPs of the code regions according to Examples 9 to 11 are shown in FIGS. 21A to 21C, respectively.

From the above experiments 1, 2, and 3, it is possible to display an optically readable information code by physically processing the wall of a resin product, either by laser light irradiation or shot blasting. was confirmed to be possible.

1 Resin product 2 Wall part 3 Outer surface 4 Code area 40 Processing area 41 Non-processing area C Information code

Claims

It is a resin product,
Equipped with a wall section,
The wall portion has a code area including a plurality of processed areas in which unevenness is formed, and a transparent non-processed area adjacent to the processed area and in which the unevenness is not formed,
The processed area has a higher light reflectance than the non-processed area, and the code area displays an optically readable information code.
resin products.
The information code is a barcode,
The processed area corresponds to a space, and the non-processed area corresponds to a bar.
The resin product according to claim 1.
The difference between the maximum reflectance R max of the processed area and the minimum reflectance R min of the non-processed area, measured using a code verification machine, is 20% or more.
The resin product according to claim 1 or 2.
The unevenness includes regularly arranged concave portions and convex portions,
In a length range of 200 μm along the arrangement direction of the concave portions and the convex portions, a height difference between at least one pair of adjacent concave portions and the convex portions is 5 μm or more and 50 μm or less,
The resin product according to claim 1 or 2.
The unevenness includes four or more pairs of adjacent recesses and protrusions with a height difference of 5 μm or more and 50 μm or less in a length range of 200 μm along the arrangement direction of the recesses and the protrusions.
The resin product according to claim 4.
The unevenness includes irregularly arranged depressions and protrusions.
The resin product according to claim 1 or 2.
The surface roughness of the processing area is 1.5 μm or more,
The resin product according to claim 6.
A container made of polyethylene terephthalate,
The resin product according to claim 1 or 2.
preparing a resin product with a transparent wall;
forming a code area on the wall portion including a plurality of processed areas in which unevenness is formed, and a transparent non-processed area adjacent to the processed area and in which the unevenness is not formed;
Forming the code area means forming the unevenness so that the light reflectance of the processed area is higher than the light reflectance of the non-processed area, thereby creating an optically readable information code. is to form a code region that displays
A method for manufacturing resin products with information codes.
Forming the code area includes forming the plurality of processing areas by irradiating the wall with a laser beam and forming the unevenness by laser marks.
A method for manufacturing a resin product with an information code according to claim 9.
Forming the plurality of processing areas includes irradiating the laser light pulse by pulse along a predetermined scanning line.
The method for manufacturing a resin product with an information code according to claim 10.
The laser light has a wavelength in the ultraviolet region,
The method for manufacturing a resin product with an information code according to claim 10.
Forming the plurality of processing areas includes irradiating the wall portion with laser light that has passed through a photomask on which a pattern representing the information code is formed,
The pattern has a shielding area that blocks the laser beam and a transmitting area that transmits the laser beam.
The method for manufacturing a resin product with an information code according to claim 12.
Forming the code region includes:
Covering the surface of the wall portion except for locations that should become the plurality of processing areas with a mask;
colliding particles with the wall portion covered with the mask, and forming the unevenness due to collision marks of the particles in areas not covered with the mask;
A method for manufacturing a resin product with an information code according to claim 9.
preparing a transparent resin material;
A mold for molding the resin material to produce a resin product having a wall portion, the mold having a plurality of first regions in which unevenness is formed, and adjacent to the first region and in which the unevenness is formed. providing a mold including a cavity surface formed with a second region that is not
molding the transparent resin material using the mold;
A code area is formed from the mold, including a plurality of processed areas to which the unevenness of the plurality of first areas is transferred, and a non-processed area adjacent to the processed area and in which the unevenness is not formed. and removing a resin product having a wall portion;
The processed area has a higher light reflectance than the non-processed area, and the code area displays an optically readable information code.
A method for manufacturing resin products with information codes.