Method for applying an image to pet

Abstract

The invention relates to contact transfer or sublimation processes. The technical result of the invention is an increase in the resistance of an applied image to environmental factors during long-term exposure, said result being achieved by the use of a method for applying an image to PET which is characterized in that prior to transfer, an image is printed on a sublimation paper using sublimation inks, thus forming a sheet with an image, then the sheet with an image is placed onto the surface on which thermal transfer is to take place, whereupon the image is transferred to PET by thermal pressing.

Description

[0001] METHOD OF APPLYING IMAGES TO PET

[0002] DESCRIPTION

[0003] The invention relates to methods of contact or sublimation transfer [B41M 5 / 382, B41M 5 / 00, B41M 5 / 035].

[0004] The closest in technical essence is the METHOD OF DECORATION [WO9815416A1], which implies the use of a method for decorating an article, especially an article made of plastic material (for example, an acrylic panel for a bathtub). The method may include applying a decal containing sublimation ink to the article. After applying the decorative material to the article, it can be molded using conventional vacuum forming technologies or using injection molding methods. In all cases, the decorative material is brought to perfection so that it (at least partially) diffuses into the surface of the article being decorated. Before applying the decorative material, a protective film can be applied to the article; in such cases, the decorative material sublimes through the protective film onto the surface of the article.Alternatively, the decorative material can be applied to the element during injection moulding so that heating is provided during the moulding process.

[0005] The main technical disadvantage of the prototype is the low resistance of the transferred image to environmental factors during their long-term impact, due to the fact that the prototype solution does not use optimal time and temperature conditions that ensure high stability of the resulting image. Also, the prototype solution does not use sublimation inks that ensure the preservation of high image quality over a long period of time.

[0006] The objective of the invention is to eliminate the disadvantages of the prototype. The technical result of the invention is to increase the resistance of the transferred image to environmental factors during their long-term exposure.

[0007] The specified technical result is achieved by using a method of applying an image to PET, characterized by the fact that before transferring using sublimation ink, an image is printed on sublimation paper, thereby forming a sheet with an image, then a sheet with an image is placed on the surface where the thermal transfer will be carried out, after which the image is transferred to PET by thermal pressing.

[0008] In particular, thermal pressing is carried out using a thermal press.

[0009] In particular, the thickness of a PET sheet ranges from 0.3 to 10 millimeters.

[0010] In particular, thermal pressing is carried out at temperatures from 150 to 200 degrees Celsius.

[0011] In particular, thermal pressing is carried out in the range of 100 to 150 seconds.

[0012] In particular, a sheet of paper is placed between the surface where thermal pressing will be carried out and the PET sheet.

[0013] In particular, a sheet of paper is placed on top of the sheet with the image.

[0014] Implementation of the invention.

[0015] In this application, the term "PET" refers to the material polyethylene terephthalate.

[0016] In this application, the term "sublimation" means the process of transition of a substance (sublimation ink) from a solid state directly to a vapor state, bypassing the melting stage. With the help of this transition, the sublimation ink evaporates from the surface of the sublimation paper and passes into the surface of the PET sheet, thereby forming an image.

[0017] In this application, the term "diffuse" means the process of penetration of a substance (sublimation ink) into the surface of a PET sheet by diffusion. The method of transferring an image to PET involves the use of a previously prepared mirror-image printed design on sublimation paper and a PET sheet. Before application, the design is mirrored using a photo editor and printed using an inkjet printer using sublimation ink on a sheet of regular or quick-drying sublimation paper, such as Al, A2, A3, A4, A5 or A6 format. Then, a PET sheet is prepared, with a thickness of 0.3 to 10 millimeters. Before applying the image, if there is a protective film on the PET sheet (on one or both sides), it must be removed.After preparing the PET sheet, the following composition is laid out - a blank sheet of paper corresponding to the size of the sublimation sheet on which the image was printed is laid as the first layer on the surface where the thermal transfer will be performed; the sublimation sheet with the printed image is laid out on top of the blank sheet, with the printed image facing up; a PET sheet without protective films is laid out on top of the sublimation sheet with the image; a blank sheet of paper, the size of which corresponds to the first blank sheet and the sublimation sheet with the printed image, is laid out on top of the PET sheet. After laying out the composition, it is pressed with thermal pressing devices, for example, a heat press at a temperature of 150 to 200 degrees Celsius and held in a closed position for 100 to 150 seconds. After the specified time has elapsed, the product is taken out and cleaned of blank sheets of paper.If a white film remains on top of the image transferred to the PET sheet (this may happen due to the types of sublimation paper, such as plain or quick-drying), wash it under running water for 5-30 seconds until the film completely disappears.

[0018] The declared technical result - increased resistance of the transferred image to environmental factors during their long-term impact - is achieved by pre-printing a drawing on sublimation paper and a PET sheet. Before application, the drawing is printed using an inkjet printer using sublimation ink. When transferring the image to the PET sheet, the sublimation ink diffuses from the sublimation paper into the surface of the PET sheet at a temperature of 150 to 200 degrees Celsius, which allows the image to be transferred directly to the surface of the PET sheet with deep penetration inside. This ensures increased resistance. After printing the image, the following composition is laid out - a blank sheet of paper is placed as the first layer on the surface where the thermal transfer will be carried out. This will prevent the PET sheet from sticking to the surface underneath it during the thermal transfer process, thereby deforming the image.A sublimation sheet with a printed image is placed on top of the blank sheet, with the printed image facing up. This allows the process of sublimation ink diffusion into the surface of the PET sheet to begin. A PET sheet is placed on top of the sublimation sheet with the image, and a blank sheet of paper is placed on top of it, which is necessary so that during the process of transferring the image, the PET sheet does not stick to the surface of the thermal pressing device due to the high temperature.

[0019] After the composition is prepared, it is placed in a thermal pressing device, after which it is pressed at a temperature of 150 to 200 degrees Celsius and held in a closed position for 100 to 150 seconds. The thermal pressing device is necessary to begin the process of sublimation of the sublimation dye from the sublimation paper onto the surface of the PET sheet. If the composition is heated at a temperature of less than 150 or more than 200 degrees Celsius, the final transferred image will be quite fragile and will begin to crack, which will reduce the quality of the final image. If the composition is heated to less than 100, the final image is not completely transferred, which will negatively affect the quality of the final image. If the image is heated for more than 150 seconds, the final image will become too fragile and will begin to crack, which will also negatively affect the quality of the final image.

[0020] After the specified time, the product is taken out and cleaned from empty sheets of paper. If a white coating remains on top of the image transferred to the PET sheet (this may happen due to the types of sublimation paper, such as plain or quick-drying), it is washed under running water for 5-30 seconds until the coating completely disappears. This is necessary to remove the coating from the final image on the PET sheet. If this is not done, the coating will cover part of the final image, which will also negatively affect its quality. As confirmation of the achievement of the technical result, the results of the experiment are presented below (Table 1), within the framework of which 12 prototypes were tested:

[0021] 1) A PET sheet onto which the image was transferred using the patented method (hereinafter referred to as Sample 1);

[0022] 2) A PET sheet onto which an image printed using regular ink was transferred from regular paper (not sublimation) using the heat pressing method (hereinafter referred to as Sample 2);

[0023] 3) A PET sheet onto which the image was transferred using the patented method, but no sheets of paper were used during the transfer (hereinafter referred to as Sample 3);

[0024] 4) An acrylic sheet onto which the image was transferred using the patented method, but without using a PET sheet (hereinafter referred to as Sample 4);

[0025] 5) A PET sheet onto which the image was transferred by UV curing of UV ink (hereinafter referred to as Sample 5).

[0026] 6) A PET sheet onto which the image was transferred using a patented method, but at a temperature of less than 150 degrees Celsius;

[0027] 7) A PET sheet onto which the image was transferred using a patented method, but at a temperature of over 200 degrees Celsius;

[0028] 8) A PET sheet onto which the image was transferred using a patented method, but the thermal transfer was carried out for less than 100 seconds;

[0029] 9) A PET sheet onto which the image was transferred using a patented method, but the thermal transfer took more than 150 seconds;

[0030] 10) A PET sheet onto which the image was transferred using the patented method, but the thickness of the PET sheet was less than 0.3 millimeters;

[0031] 11) A PET sheet onto which the image was transferred using the patented method, but the thickness of the PET sheet was more than 10 millimeters;

[0032] 12) A PET sheet onto which an image was transferred using the patented method, but the image was turned away from the PET;

[0033] After the tests, the final image transferred to the declared sheet material was compared with the reference transferred image (transfer quality percentage 99.7%). The difference between the obtained and reference images was recorded and later converted into a percentage ratio, which is indicated in Table 1.

[0034] Table 1

[0035] Based on the results of the study, the following conclusions can be drawn:

[0036] 1) To transfer the image, maintain the proper level of quality and resistance to external influences, it is necessary to use only sublimation paper as a template for transfer and sublimation ink;

[0037] 2) The percentage of quality of the final image transferred to PET by the sublimation method is higher than that transferred using the UV curing method known from the prior art;

[0038] 3) If there are no sheets in the composition, the PET sheet sticks to the surface during thermal heating, which subsequently worsens the quality of the final image; 4) If the thickness of the PET sheet is less than 0.3 mm, the sheet is deformed during thermal heating, which negatively affects the final image;

[0039] 5) If the thickness of PET is more than 10 millimeters, during the thermal heating process, the image applied to sublimation paper using sublimation ink is not transferred to PET by sublimation, which, as a result, does not allow the image to be applied at all;

[0040] 6) If the sheet with the printed image is not placed with the printed side facing the PET sheet, the image is not transferred at all;

[0041] 7) If thermal pressing is carried out at a temperature of less than 150 degrees Celsius, the final image does not completely diffuse into PET, which leads to rapid abrasion of the pattern from external irritants;

[0042] 8) If thermal pressing is carried out at a temperature of more than 200 degrees Celsius, the final image dries out too much, which leads to cracks and a decrease in the final quality of the transferred image;

[0043] 9) If thermal pressing is performed for less than 100 seconds, the final image does not completely diffuse into the PET, which leads to rapid abrasion of the image from external irritants;

[0044] 10) If thermal pressing is performed for less than 150 seconds, the final image dries out too much, which leads to cracks and a decrease in the final quality of the transferred image.

Claims

FORMULA 1. A method for applying an image to PET, characterized by the fact that before transferring using sublimation ink, an image is printed on sublimation paper, thereby forming a sheet with the image, then a sheet with the image is placed on the surface where the thermal transfer will be carried out, after which the image is transferred to PET by thermal pressing.

2. The method according to paragraph 1, characterized in that thermal pressing is carried out using a thermal press.

3. The method according to item 1, characterized in that the thickness of the PET sheet is from 0.3 to 10 millimeters.

4. The method according to item 1, characterized in that thermal pressing is carried out at a temperature of 150 to 200 degrees Celsius.

5. The method according to item 1, characterized in that thermal pressing is performed in the range from 100 to 150 seconds.

6. The method according to paragraph 1, characterized in that a sheet of paper is placed between the surface where thermal pressing will be carried out and the PET sheet.

7. The method according to paragraph 1, characterized in that a sheet of paper is placed on top of the sheet with the image.