Direct food contact ink

Abstract

To provide a pigment and an ink composition containing the pigment, which have a wide color gamut for enabling to print more clear color and propose physical properties to be satisfied such as wear resistance, while being safe to direct and indirect food contact.SOLUTION: An ink contains colorants and other substances that comply with regulations governing the amount of substances deemed safe when one or more of the ink's components migrate into food or beverages. The ink demonstrates resistance to removal. An ink set is also described. The ink provides a wide color gamut.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 872,879, filed Jul. 11, 2019, which is hereby incorporated by reference in its entirety for all purposes.

Background Art

[0002] Food packaging uses paper and other materials such as cardboard and plastic. Often, these materials directly contact the packaged food through the flow of commerce and ultimate end use by the consumer, such as wrapping and containing them. Another direct food contact (DFC) application is paper drinking straws. Paper straws have been around for a long time and have generally been replaced by plastic drinking straws, but are making a comeback due to many problems caused by plastic waste such as environmental issues. For example, a common problem is that paper degrades while many plastics do not.

[0003] Since paper straws were first supported, the health and safety regulations governing direct food contact applications have changed. Currently, many straws are printed with inks containing non-direct food contact pigments to obtain bright colors. This may be because food contact approved pigments based on iron oxide give duller colors that are not as bright and thus not aesthetically pleasing. Bright and vivid colors cannot be produced from such pigments.

[0004] In the United States, 21 CFR§178.3297 regulates polymer colorants. This section describes the limits on the amounts of listed colorants and other substances. However, the list in this section seems old and does not necessarily consider other substances present in the colorants (these substances are called substances not intentionally added (NIAS)). Furthermore, it lists mainly inorganic pigments, which has the drawback of providing only a limited color gamut.

[0005] European regulations list approved food colorants, and there are inks for direct food contact that utilize these colorants. However, a September 2016 survey by the European Food Safety Authority (EFSA) showed that the approved food colorants themselves are insufficient to guarantee their safety when in direct contact with food. Also, these food colorants provide only a limited color gamut and, in many cases, do not possess sufficient resistance such as moisture and dryness resistance, nor do they provide sufficient light and chemical resistance.

[0006] The three major food contact material (FCM) regulatory systems, namely the United States, the European Union, and China, have the same goal of preventing substances from migrating into food at levels that could pose a risk to human health. For example, there are some variations in this wording, such as the FDA rules that refer to unintended food additives, but the goal is the same.

[0007] In Europe, the safety of food contact materials is regulated by the Framework Regulation (EC) No. 1935 / 2004. Article 5 of this regulation contains provisions regulating specific food contact materials. One such regulation regarding specific food contact materials is the Plastic Regulation (EU) No. 10 / 2011. The Plastic Regulation includes a positive list of substances with specific migration limits. Link to the regulation: https: / / eur-lex.europa.eu / legal-content / EN / TXT / ?qid=1592209990405&uri=CELEX:32011R0010

[0008] In Switzerland, the Federal Department of Home Affairs (FDHA) adopted an amendment to the ordinance of November 23, 2005 (SR 817.023.21) regarding the regulation of materials and articles related to packaging inks. The requirement is that only permitted substances should be used in the manufacture of packaging inks. Permitted substances are defined as those listed in Annex 2, Lists I and II, and Annex 10. Substances listed in Annex 2 refer to those listed in the Plastic Regulation (EU) No. 10 / 20011. Substances listed in Annex 10 are divided into List A and List B. Substances listed with List A status have either the specified migration limit (SML) cited or a default international migration limit of 60 mg / Kg (60 ppm). Substances listed with List B status have a default migration limit of 0.01 mg / Kg (10 ppb). Link to Annex 10 of the Swiss ordinance: https: / / www.blv.admin.ch / dam / blv / en / dokumente / lebensmittel-und-ernaehrung / rechts-und-vollzugsgrundlagen / lebensmittelrecht2017 / anhang10-verordnung-materialien-kontakt-lm-gg.pdf.download.pdf / Annex-10-ordinance-fdha-materials-and-articles-intended-to-come-into-contact-with-food-stuffs.pdf

[0009] In the United States, Title 21 of the Code of Federal Regulations regulates food and drugs within the United States. Title 21 is administered by the Food and Drug Administration, the Drug Enforcement Administration, and the National Drug Intelligence Center. For food contact materials, there is a regulation on unintended food additives. In FDA 21 CFR§175.300(b)(1)-(3), coatings can be formulated from: · substances generally recognized as safe in food, · Substances that are permitted for use by rule or prior approval and are employed under specific conditions of prior approval or authorization, · Substances that are the subject of other regulations and comply with any specifications of such other regulations, and · Substances specifically listed in 21 CFR§175.300(b)(3). Link to FDA 21 CFR§175.300: https: / / www.govinfo.gov / app / details / CFR-2011-title21-vol3 / CFR-2011-title21-vol3-sec175-300

[0010] China adopted a new overall Food Safety Law on June 1, 2009. This replaced the 1995 Food Hygiene Law and requires approval of all "food-related products", including food packaging materials and equipment used in food production. This Food Safety Law includes the horizontal standard GB9685-2016, which contains a positive list of additives for food contact materials. The Food Safety Law also includes material standard specifications titled GB 4806.x, where x indicates the number associated with a specific food contact material. Link to Chinese standards: https: / / www.chinesestandard.net / PDF.aspx / GB9685-2016

[0011] Inks used for non-direct food contact applications such as inks can be printed on the outside of food packaging and may typically contain pigments that are inappropriate for direct food contact applications. This is because there are toxicological concerns either with the pigment itself or, more commonly, with the residual substances contained in the pigment. For example, most of the red, orange, and yellow pigments used in food packaging are based on mono- or di-arylide azo chemistry and thus contain residual amounts of unreacted primary aromatic amines (PAAs). The residual levels of unreacted PAAs are typically regulated to the levels indicated by the Council of Europe's Resolution AP(89)1. In the case of non-DFC applications, this is acceptable as PAAs have been shown to be relatively non-migratory, but in the case of DFC applications, migration can occur at levels that are unsafe for human consumption. The problem of migration can be exacerbated by certain types of foods such as acidic foods. In any case, the amount of migration can result in unsafe food, thereby violating Regulation (EC) No 1935 / 2004, which provides that the migration of substances from food contact materials should not pose a risk to human health.

[0012] The problem of migration is not limited to red, orange, and yellow pigments. For example, the most common green pigment is Pigment Green 7, which has a chlorinated copper phthalocyanine structure. This pigment contains residual levels of hexachlorobenzene, which renders the pigment inappropriate for DFC applications.

[0013] Some colorants have been approved for use in cosmetic applications and may at first glance appear to be a good starting point for DFC ink colorants. However, upon closer examination, in many cases, the regulatory constraints on cosmetic colorants are not more stringent than those on inks for food packaging. An example of this is the Council of Europe's AP(89)1 standard specification, which is adopted by most ink manufacturers and some regulatory authorities and has restrictions on the PAA content (primary aromatic amines) in colorants, while the European Cosmetics Regulation does not have such restrictions.

[0014] Some of the most common natural food colorants are carotenoids, chlorophyll, anthocyanins, and turmeric. These dyes, which have been used for centuries, exhibit low lightfastness and thus will fade over time. Carotenoids have a deep red, yellow, or orange color. For example, beta-carotene, which is responsible for the bright orange color of sweet potatoes and pumpkins.

[0015] Chlorophyll is found in all green plants. This molecule absorbs sunlight and uses its energy to synthesize carbohydrates from carbon dioxide and water.

[0016] A good natural source of deep purple and blue colors is anthocyanins. Grapes, blueberries, and cranberries are richly colored thanks to this organic compound. Unlike beta-carotene, anthocyanins, which form a group of similar compounds rather than a single compound, are water-soluble.

[0017] Other natural food colorants include Annatto (E160b) (CAS No. 1393-63-1), a reddish-orange dye made from the seeds of achiote, Caramel color (E150a-d) made from caramelized sugar, Carmine (E120), a red dye derived from the cochineal scale insect, Dactylopius coccus, Elderberry juice (E163), Lycopene (E160d), Paprika (E160c), Turmeric (E100), Curcumin, a bright yellow chemical produced by the Curcuma longa plant. It is the main curcuminoid of the turmeric (Curcuma longa) plant of the ginger family, Zingiberaceae. It is sold as a herbal supplement, a cosmetic ingredient, a food flavoring, and a food colorant. Chemical formula: C 21 H20 O6, Appearance: bright yellow to orange powder, CAS No.: 458-37-7.

[0018] DFC ink was prepared with a curcumin dye-based liquid at 25% by weight in DFC-TVST1 and compared with the standard yellow DFC ink GAQS-20598. The food coloring ink was very weak and had a lightfastness of less than Blue Wool 1. It completely disappeared within 11 minutes in the Xenotester.

[0019] Therefore, there is a need for pigments and ink compositions containing pigments that are safe for direct and indirect food contact, have a wider color gamut to enable brighter color printing, and have satisfactory physical properties such as rub resistance.

[0020] Possible reference materials include the following: JP6152130 - Printing paper, US20110163179 - Drinking straw with opaque, imprinted side, GB787981 - Improved method and apparatus for forming drinking straws or tubes having printed matter thereon, US5671667 - Multi-line straw printer, and US6155478 - Paper cup with sipping straw formed thereon.

Summary of the Invention

[0021] The present invention relates to inks having a wide color gamut, bright colors, an extended color gamut, improved dot printing suitability, increased flexibility, and sufficient physical and chemical resistance properties, particularly for use in direct food contact (DFC) applications.

[0022] Printing inks that are safe for direct food contact are described herein, the inks each comprising an organically colored agent of a preselected color, and the organically colored agent and other chemicals comprising the ink being determined to be safe for contact with food by either worst-case calculations or migration tests to evaluate human exposure to the substance, referring to regulatory positive lists, or following an EFSA-based substance risk assessment process, and having migration values such that the ink exhibits resistance to removal.

[0023] In another aspect, the described printing ink exhibits a chroma value (C) that is 10% or more of the chroma value (C) of an ink colored with an inorganic colored agent of the same color.

[0024] In another aspect, the described printing ink exhibits a chroma value (C) that is 20% or more of the chroma value (C) of an ink colored with an inorganic colored agent of the same color.

[0025] In another aspect, the organically colored agent of the described printing ink is selected from Parion Yellow D1818, Irgazin Orange D2905, Irgazin Rubine L4025, Helio Gen Blue D6840, Chromophthal Violet D5700, Sunchroma C47-2222, and mixtures thereof.

[0026] In another aspect, the organically colored agent of the described printing ink is selected from pigments corresponding to one of Color Index Yellow 139, Orange 71, Red 264, Red 122 (pink in appearance), Blue 15:0, Violet 37, Black 7, White 6, and mixtures thereof.

[0027] In another aspect, the organic colorants of the described printing ink are selected from isoindoline yellow, diketopyrrolopyrrole orange, diketopyrrolopyrrole red, quinacridone red, phthalocyanine blue, dioxazine violet, carbon black, titanium dioxide, and mixtures thereof.

[0028] In another aspect, the migration values of the organic colorants and other chemicals in the described printing ink are below the threshold for a 60 kg human according to the EU cube model for food packaging, which is a 10 cm × 10 cm × 10 cm cube containing 1 kg of food.

[0029] In another aspect, the migration values of the organic colorants and other chemicals in the described printing ink are below the threshold for a 70.3 kg human according to the paper straw scenario described later in this disclosure.

[0030] In another aspect, the migration values of the organic colorants and other chemicals in the described printing ink are below the threshold for a 40.7 kg human according to the paper straw scenario.

[0031] In another aspect, the migration values of the organic colorants and other chemicals in the described printing ink are below the threshold for a 20.9 kg human according to the paper straw scenario.

[0032] In another aspect, the migration values of the organic colorants and other chemicals in the described printing ink are below the threshold for a 12.7 kg human according to the paper straw scenario.

[0033] In another aspect, the described printing ink further comprises an industrial varnish composed of at least some of the other chemicals.

[0034] In another aspect, an aqueous acrylic emulsion safe for food contact is present in the industrial varnish as at least one of the other chemicals.

[0035] In another aspect, the wax is present in the ink as at least some of the other chemicals.

[0036] In another aspect, the printing ink described includes additives selected from adhesion promoters, silicones, light stabilizers, deaerating additives, ammonia, flow promoters, defoamers, antioxidants, stabilizers, surfactants, dispersants, plasticizers, rheology additives, waxes, silicones, etc., and combinations thereof, as at least some of the other chemicals.

[0037] In another aspect, a process for formulating an ink that is safe for direct contact with food is described herein, the process comprising a) establishing safe migration limits for each substance used in the ink system, and b) using only substances that meet the safe migration limits.

[0038] In another aspect, a process for identifying organic colorants for an ink that is safe for direct contact with food is described herein, the process comprising a) establishing safe migration limits for each colorant, and b) selecting colorants having a chroma value of ≧ 10% compared to an inorganic colorant of a comparative example.

[0039] In another aspect, a printing ink set that is safe for direct food contact is described herein, the inks in the set being of different colors and providing a wide color gamut, the inks in the set including organic colorants, and the organic colorants and other chemicals including the inks having migration values determined to be safe for contact with food by evaluating human exposure to the substances by either worst-case calculation or migration testing, referring to a regulatory positive list, or following an EFSA-based substance risk assessment process, and the inks exhibiting resistance to removal.

[0040] In another aspect, the printing ink set includes red, yellow, orange, blue, purple, black, pink, and transparent colored inks.

[0041] In another aspect, the chroma value (C) of each of the inks in the set is 10% or more of the chroma value (C) of the ink colored with the same color inorganic colorant.

[0042] In another aspect, the chroma value (C) of each of the inks in the set is 20% or more of the chroma value (C) of the ink colored with the same color inorganic colorant.

[0043] In another aspect, the migration values of the organic colorants and other chemical substances contained in the inks in the set are below the threshold values for a 60 kg human according to the EU Cube model.

[0044] In another aspect, the migration values of the organic colorants and other chemical substances contained in the inks in the set are below the threshold values for a 70.3 kg human according to the paper straw scenario.

[0045] In another aspect, the migration values of the organic colorants and other chemical substances contained in the inks in the set are below the threshold values for a 40.7 kg human according to the paper straw scenario.

[0046] In another aspect, the migration values of the organic colorants and other chemical substances contained in the inks in the set are below the threshold values for a 20.9 kg human according to the paper straw scenario.

[0047] In another aspect, the migration values of the organic colorants and other chemical substances contained in the inks in the set are below the threshold values for a 12.7 kg human according to the paper straw scenario.

[0048] In another aspect, a printed article includes a substrate and one or more of the printing inks of the present disclosure.

[0049] In another aspect, the printed article and its printed side are suitable for direct contact with food.

[0050] In another aspect, the substrate includes paper, paperboard, metallized paper, polyethylene, foil, metallized film, and polymer film.

[0051] In another aspect, the article is a paper drinking straw.

[0052] In another aspect, a method for preparing a printing substrate that is safe for direct contact with food is described herein. The method includes

[0053] printing the substrate with one or more inks described herein, and

[0054] drying the substrate.

[0055] In another aspect, printing inks that are safe for direct food contact are disclosed herein. Each individual ink includes an organic colorant of a preselected color, and the organic colorant and other chemicals including the ink have migration values determined to be safe for contact with food by one or both of (a) a migration test of the organic colorant and other chemicals, and (b) compliance with regulations indicating the amount of organic colorant considered safe for contact with food.

[0056] In one aspect, the resistance to removal exhibited by the ink means that the ink exhibits resistance to removal when printed on a surface exposed to a liquid reagent. In another aspect, the resistance to removal exhibited by the ink is such that the ink has resistance to removal when printed on a surface that is rubbed, such as when the ink-containing surface is wet and / or when they are dry, and during normal use of the printed article, which can be, for example, in food packaging or a drinking straw. The ink can exhibit all of these aspects.

[0057] The selection of pigments that are safe for direct food contact is one aspect of the present disclosure. There is no list of organic pigments suitable for direct food contact (DFC) ink applications within the regulatory frameworks of the United States, the European Union, and China. The applicant has found pigments that are safe for direct food contact, provide a wide color gamut, and provide chemical and physical resistance.

[0058] The issues associated with residual substances found in pigments that raise toxicological concerns were discussed in the first half of the present disclosure. In some cases regarding the pigments used to make the DFC inks described herein, higher purity versions of commonly used pigments of certain Color Index numbers may be used. This example is Pigment Black 7, carbon black, which is one of the pigments described herein that has been found to be safe for direct food contact. This pigment is typically manufactured by the thermal decomposition and partial combustion of a fuel source, followed by the collection of soot or ash. The differences that affect the quality of the resulting Pigment Black 7 include, but are not limited to, the starting fuel, the geometry of the thermal decomposition and partial combustion, the oxygen level, the temperature, and the collection method. In all cases, some level of polycyclic aromatic hydrocarbons is formed, which can be substances of toxicological concern. In the present invention, the grade of Pigment Black 7 contains a concentration of polycyclic aromatic hydrocarbons that is less than one-tenth of the concentration normally found in grades of Pigment Black 7 recommended for food contact material applications. In other cases, pigments not normally used in food contact material applications were selected for the present invention either because they have very low levels of residual substances or because they have residual substances with low toxicological concerns.

[0059] The present disclosure relates to inks having a wide color gamut, bright colors, an extended color gamut, improved dot printing suitability, increased flexibility, and sufficient physical and chemical resistance properties, which can be used particularly in printed materials having direct food contact (DFC) applications. The advantages of the inks of the present invention can be evaluated by considering the following four scenarios: 1. Direct food contact inks made with food colorants are safe for direct food contact use and have a wide color gamut, but these inks do not provide resistance to removal characteristics. 2. Direct food contact inks made with inorganic pigments such as iron oxide are safe for direct food contact use and have effective resistance, but do not have a wide color gamut. 3. Inks made for non-direct food contact applications have effective resistance and a wide color gamut, but are not safe for use in direct food contact applications. 4. The inks described herein are safe for direct food contact use, have a wide color gamut, and have resistance.

[0060] These four scenarios are shown in the Venn diagram shown in FIG. 5, and the fourth scenario corresponds to the inks described herein, which are safe for direct food contact applications, provide a wide color gamut, and have resistance.

Brief Description of the Drawings

[0061]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0062] The specific terms used in this disclosure have the following meanings: "Migration value" - the amount of substance that can migrate from the ink into the surrounding environment, expressed in mg / kg food or μg / kg food. The amount is either the maximum amount possible under worst-case calculations or the amount determined by the migration test.

[0063] "Worst-case calculation" is the amount of substance migration based on the assumption that all substances in the ink composition migrate from the ink into the food (i.e., 100% migration).

[0064] "Migration test" refers to a test conducted by analysis using GC-MS (gas chromatography-mass spectrometry) and / or analysis using liquid chromatography-mass spectrometry (LC-MS). Test methodology: A printed material, 100 cm 2 was extracted in 20 ml of 50% ethanol at room temperature for 6 hours. After 6 hours, the printed material was removed and a 1 ml aliquot was analyzed by HPLC-MS (using IM373 instrument parameters). The remaining sample was liquid-liquid extracted in 40 ml of dichloromethane (DCM). Then, the DCM was evaporated to 1 ml and GC-MS (IM304 instrument parameters) was operated. The printed sample was compared with the provided unused substrate and only ink-related peaks were identified.

[0065] "Regulatory positive list" - a list shown in one or more of the EU plastic rules, the EFSA opinion, the provisional list of additives used in plastics, and the Swiss ordinance in Table 11. The main sections include: · Plastic Regulation (EU) No. 10 / 2011. The plastic regulation includes a positive list of substances with specific migration limits. Link to the regulation: https: / / eur-lex.europa.eu / legal-content / EN / TXT / ?qid=1592209990405&uri=CELEX:32011R0010 (previously mentioned on page 2), · Link to the EFSA website: http: / / www.efsa.europa.eu / · Link to the provisional list of additives used in plastics: https: / / ec.europa.eu / food / sites / food / files / safety / docs / cs_fcm_legis_additives-prov-list.pdf · Link to Annex 10 of the Swiss Ordinance: https: / / www.blv.admin.ch / dam / blv / en / dokumente / lebensmittel-und-ernaehrung / rechts-und-vollzugsgrundlagen / lebensmittelrecht2017 / anhang10-verordnung-materialien-kontakt-lm-gg.pdf.download.pdf / Annex-10-ordinance-fdha-materials-and-articles-intended-to-come-into-contact-with-food-stuffs.pdf (already mentioned on page 3).

[0066] The "EFSA-based substance risk assessment process" is based on a threshold approach to toxicological concerns for risk assessment by the European Food Safety Authority (EFSA), as clarified in the following documents: 1. EFSA Document: Outcome of the public consultation on the draft guidance on the use of the Threshold of Toxicological Concern approach in food safety assessment. APPROVED: 17 May 2019, doi:10.2903 / sp.efsa.2019.EN-1661 2. EFSA Document: Guidance on the use of the Threshold of Toxicological Concern approach in food safety assessment, ADOPTED: 24 April 2019, doi:10.2903 / j.efsa.2019.5708 3. EFSA Document: Priority topics for the development of risk assessment guidance by EFSA’s Scientific Committee in 2016 - 2018, ADOPTED: 19 May 2016, doi:10.2903 / j.efsa.2016.4502 4. EFSA and WHO document: Review of the Threshold of Toxicological Concern (TTC) approach and development of new TTC decision tree. PUBLISHED: 10 March 2016 5. EFSA Document: Scientific Opinion on Exploring options for providing advice about possible human health risks based on the concept of Threshold of Toxicological Concern (TTC). EFSA Journal 2012;10(7):2750, and 6. European Printing Ink Trade Association (EuPIA) document: EuPIA Guidance for Risk Assessment of Non-Intentionally Added Substances (NIAS) and Non-Evaluated or Non-Listed Substances (NLS) in printing inks for food contact materials”, available at: https: / / www.eupia.org / fileadmin / Documents / Risk_Assessment / 2020-03-12-EuPIA_NIAS_Guidance.pdf. In particular, see the 15-page overview diagram.

[0067] "Resistance to removal" means obtaining a score of 4 or higher in one or more of the following tests when the ink is printed on a paper substrate: The immersion test, The bleed test, and The SATRA dry rub resistance test. The results of these tests are evaluated on a scale of 1 - 5. The methodologies of these tests are shown elsewhere in this specification.

[0068] "Wide color gamut" refers to the six major color indices covered by the organic colorants described herein (i.e., the six color indices listed in Table 2), which, together with black, achieve 98% of the color shades of the Pantone Matching System (PMS).

[0069] In clarifying the present disclosure regarding direct food contact inks and other chemicals present in the ink, the inventors utilized the chemical properties, analytical capabilities, and regulatory risk assessment skills of the ink and pigments to determine colorants and other chemicals that can be safely used in DFC inks. These determinations included an evaluation of substances that may migrate into food at levels that can endanger human health and / or substances that may be considered unintended food additives present at levels that can endanger human health.

[0070] The following approach was adopted to find colorants (preferably organic colorants) and other materials suitable for inks for direct food contact: 1. Considering the color index numbers of pigments representing colors across the visible light spectrum, color index numbers were determined that are likely not to contain substances of concern from the perspective of food safety. Also, consideration was given to where these pigments are in color space so that a wide color gamut ink set can be provided (seven major color indices for achieving 98% of the color shades of the Pantone Matching System (PMS)). 2. For the purpose of identifying the grade of pigments corresponding to the color index numbers determined to be potentially safe in Step 1, information was requested from pigment manufacturers on the premise that such pigment grades may not contain substances that migrate to toxic (i.e., unsafe) levels. 3. Other substances (resins, solvents, additives, etc.) used to formulate inks and coatings that are safe for food and / or have low migration levels were identified. 4. Analytical tests, i.e., migration tests, were performed on both the supplied pigments and other materials. Furthermore, after ink formulation and after printing the ink on a substrate, migration tests were performed to determine the amount of ink components, i.e., pigments and other substances, that migrated. 5. Based on known information about impurities in pigments and other substances, information obtained from suppliers, manufacturers, etc., and information provided by analytical data collected in extraction and migration tests, substances that may raise concerns in terms of not conforming to the rules for managing amounts safe for direct food contact were determined. 6. Safe migration limits (SMLs), i.e., amounts that are safe for humans if they migrate from the ink into the surrounding food, were established for each of these substances. Many of these substances are NIAS, and since NIAS is outside the scope of many specific regulations, they do not have published migration limits. However, it is still possible to create self-derived migration limits using a risk assessment-based methodology considering the toxicology of the substances and appropriate exposure models. Applying this methodology, it was determined that the materials used do not contain substances that would migrate into food at levels that would pose a significant risk to human health with a significant margin of safety.

[0071] This process is illustrated in the following steps: A. The step of identifying colorants and other materials determined to have low migration amounts, low extraction amounts, and low toxicity according to 1 - 6 above. B. The step of selecting colorants that meet the conditions of the color gamut according to 1 - 6 above. C. Performing an analytical test to confirm that the colorant and other materials meet the criteria set in Steps A and B, and D. Adopting only colorants and other materials that meet the criteria of A and B.

[0072] In addition to being safe for direct food contact and providing a wide color gamut, the ink should also exhibit good adhesion to the substrate and resistance to removal characteristics.

[0073] In one aspect, the inks described herein include ink sets that meet safety, adhesion, and resistance criteria. The ink set can include direct food contact inks in black, orange, red, yellow, purple, blue, pink, white, and transparent colors. White is derived from inorganic titanium dioxide, and thus, in another alternative aspect, white coloring will not be included in the ink set.

[0074] The transparent ink is a pigment-free version of a colored ink, such as a mixture of the industrial varnish of Example 1 with wax and / or additives as described below, as needed.

[0075] Mixtures of the above colorants may be produced to generate inks of other colors (e.g., green ink). Also, additional colors based on pigments (preferably organic pigments) and other materials that are considered safe for DFC in amounts below the SML (Specific Migration Limit) may be used and / or produced, as exemplified in Tables 11 - 16 below.

[0076] In one aspect, the direct food contact ink can be made from the formulation of two intermediates, namely, a pigment concentrate and an industrial varnish, where the pigment concentrate provides the desired hue and color strength, while the industrial varnish provides chemical and physical resistance.

[0077] In one aspect, when forming a print on a substrate, a primer coat can be applied before applying the ink. In another aspect, an overprint varnish (OPV) can be applied over the ink. In another aspect, all three of the primer, ink, and overprint varnish are applied to the substrate. These aspects enhance the resistance of the final printed layer. The ink can also be used with or without OPV and still retain their overall resistance.

[0078] The inks described can also include wax. Such waxes include, but are not limited to, amide waxes, erucamide waxes, polypropylene waxes, paraffin waxes, polyethylene waxes, Teflon®, carnauba waxes, etc. The wax can be a combination of two or more waxes. In one aspect, a mixture of amide and erucamide waxes is included in the ink composition. The wax, when present, is present in an amount of about 0.1 wt% to about 4.0 wt% based on the total weight of the composition. The wax is preferably present in an amount of about 0.1 wt% to about 2.0 wt%.

[0079] As with most ink and coating compositions, additives can be incorporated to enhance various properties. A partial list of such additives includes, but is not limited to, adhesion promoters, silicones, light stabilizers, degassing additives, ammonia, flow promoters, defoamers, antioxidants, stabilizers, surfactants, dispersants, plasticizers, rheology additives, waxes, silicones, etc., and combinations thereof.

[0080] The inks described herein are preferably suitable for printing on, among other materials, paper, cardboard, foil, metallized paper or film, and polymer films. The materials to be printed can be formed into, among other items, various food contact products, such as drinking straws, cups, food trays, food containers, food packaging, food wrapping, cooking utensils.

[0081] The inks described can be formulated for printing by almost any printing method, such as, inter alia, inks for lithography, screen, flexo, gravure, inkjet printing, etc.

Examples

[0082] The following examples illustrate specific aspects of the invention and are not intended to limit its scope in any way and should not be so construed.

[0083] As shown, the inks described can include industrial varnishes that are safe for direct contact with food. Exemplary varnish compositions are shown below: Example 1: DFC industrial varnish (DFC-TV)

Table 1

[0084] Suitable acrylic emulsions are available from BASF, DSM, Lubrizol, Exograph, etc. Another suitable acrylic emulsion is Joncryl® ECO2124 from BASF, and the formulator will select the acrylic emulsion that is optimal for their end-use requirements. The amounts can vary ±2.0% from the amounts above.

[0085] Organic colorants safe for direct food contact Table 2 lists the pigments that the applicant has found to be safe for direct food contact and that provide a wide color gamut and excellent resistance.

Table 2

[0086] Carbon black and titanium dioxide can be mixed with these colors to provide a wider range of colors. Carbon black available from Sensient Technologies, New Jersey, USA or Sun Chemical, New Jersey, USA is preferred. Suitable titanium dioxide is available from Venator Materials PLC, Houston TX, USA.

[0087] Examples 2 - 7: Color Concentrate Base The color concentrate base was prepared by blending the direct food contact industrial varnish described in Example 1 with the DFC - based concentrate described in Table 2. The ink is prepared by mixing the industrial varnish with the DFC - based concentrate. The amounts can vary by ±2.0% of the stated values.

Table 3

[0088] Examples 8 - 13: Inks Safe for Direct Food Contact Inks safe for direct food contact are shown in Table 4.

Table 4

[0089] Example 14: DFC Overlacquer The DFC overlacquer was prepared by mixing 98 wt% of the DFC - TV of Example 1 with 2.0 wt% of carnauba wax.

[0090] Printing Preparation The ink viscosity was measured with a Zahn 2 - cup at 20°C and printed at 9.5 cc / m on a Windmoeller & Hoelscher Soloflex printing press with an anilox of 12 cc / m 2 of 2When printing on MGBK paper at 50 m / min using anilox (excluding black), it is reduced to 25 s using water. The drying oven was maintained at 60 °C. MGBK paper is a typical paperboard used in the manufacture of paper straws. Maximum airflow is preferred during drying.

[0091] The resulting printed matter was tested for brightness, soakability, bleed, and rub resistance. The results are shown in Tables 5 - 9 below. The inks described herein were compared to commercially available drinking straw inks and commercially available DFC inks based on iron oxide pigments available from Sun Chemical. It should be noted that the inks described herein provide either similar or better properties when compared to other inks having an overprint varnish on top of the layer.

[0092] Also, it is possible to produce the ink without first preparing the pigment concentrate and varnish simply by grinding the pigment into the base and mixing the resulting material with the remaining ink formulation components.

[0093] Table 5 - Color The brightness / clarity of the inks described herein was measured using an X - Rite Exact spectrophotometer (light source D50, observer angle 2°, filter MO) and they were compared to direct food contact approved inks using iron oxide - based pigments.

Table 5

[0094] The color range of iron oxide pigments is limited to dull, muddy hues of reddish - brown, yellow, and black. The ability to provide bright and clean hues to end - users does not actually exist. This demonstrates the importance of the pigments and inks described herein that comply with direct food contact, which have a wide color gamut that provides most of the PMS color shades and thus allows for more options for the end - user of the ink.

[0095] The table above shows the color data measurement values of the Xrite spectrophotometer under D50, which is a CIE "warm-colored" daylight source with a 2° field of view. The table enables a comparison of the DFC inks described herein with commercially available DFC inks based on iron oxide pigments (i.e., comparative examples). As shown, the DFC inks described herein exhibit brightness and cleanliness far exceeding those of the iron oxide DFC inks. For example, the yellow and red inks of the DFC described herein are brighter and exhibit higher color purity and intensity (chroma) when compared to the iron oxide inks.

[0096] The yellow and red inks of the DFC described herein are brighter with a higher intensity (chroma, C value) when compared to the iron oxide inks.

[0097] Color gamut: A wide color gamut will include primary colors located further out in the CIELAB color space. These colors have a cleaner hue (higher chroma value C), and thus will enable a wider range of hues to be matched by mixing different primary colors. Chroma (C) is the square root of the sum of the squares of a* and b*.

[0098] The ink of Comparative Example 16 containing an inorganic red oxide pigment has a chroma value (C) of 47.24, while the red ink of Example 10 of the present invention containing an organic pigment (Irgalazin Rubine L4025) has a chroma value of 60.44, which is 28% higher than that of Comparative Example 16. The Comparative Example 15 ink contains an inorganic yellow oxide pigment and has a chroma value of 52.16, whereas Example 8 of the present invention containing an organic yellow pigment (Paliotol Yellow D1818) has a C of 64.84, which is 24% higher. The ink of Comparative Example 17 contains an inorganic blue pigment and has a chroma value of 35, while Example 11 of the present invention containing an organic blue pigment (Helio Gen Blue D6840) has a C = 52.9, which is 51% higher.

[0099] In the field of color physics, it is known that red and yellow represent the colors that are most difficult to obtain a wide color gamut with the use of organic pigments as compared to inorganic ones (e.g., iron oxide pigments). Therefore, the rate of increase in chroma is equal to or higher for the remaining colors of the ink sets of the present invention as compared to the comparative inks based on inorganic pigments (e.g., iron oxide pigments).

[0100] In one aspect, the chroma values of the inks being described currently are at least 10% higher than their inorganic equivalents (e.g., iron oxide equivalents). In another aspect, the chroma values of the inks being described currently are at least 20% higher.

[0101] Figures 1 and 2 demonstrate this point. Figure 1 shows that when calibrated printed under the same conditions where the calibration printing condition was flexo using a 200# anilox manual roller, the DFC yellow ink of Example 8 has a chroma 24% higher than that of Comparative Example 15.

[0102] Figure 2 shows that when calibrated printed under the same conditions, the DFC red ink of Example 10 of the present invention has a chroma 28% higher than that of Comparative Example 16.

[0103] As shown in Figures 3 and 4, the CIELAB color space (also known as CIE L*a*b* or sometimes simply abbreviated as the "Lab" color space) is a color space defined by the International Commission on Illumination (CIE) in 1976. It represents color as three values: L* for lightness from black (0) to white (100), a* for green (-) to red (+), and b* for blue (-) to yellow (+).

[0104] Since the L*a*b* model is a three-dimensional model, it can be properly represented only in three-dimensional space. The two-dimensional depiction includes a chromaticity diagram, which is a section of a color solid having a fixed lightness.

[0105] Figure 4 illustrates the CIELCh color space as a CIELab cube color space, where instead of Cartesian coordinates a* and b*, cylindrical coordinates C* (chroma, relative saturation) and h° (hue angle, the angle of the hue on the CIELab color wheel) are specified. The CIELab lightness L* remains unchanged. At low saturation values, colors are weaker, appear pastel, and often have a muddy and / or cloudy color. At high saturation values, colors are intense, vibrant, and clean. Saturation values are used in this description to demonstrate the difference between colors produced by inorganic iron oxide-based inks and the colors produced by the direct food contact inks described herein, which offer a wide color gamut.

[0106] The inks described herein were subjected to dip, bleed, and rub tests and compared to a comparative iron oxide ink.

[0107] In the immersion test, the print was immersed in a liquid reagent and then removed after 1 hour, patted dry, and evaluated to determine if there was any removal of the print. [Table 6]

[0108] Table 2 shows that the inks described herein have comparable soaking properties to the commercially available iron oxide ink used in the comparative example, where the ink is used to print drinking straws, among other applications.

[0109] For the bleed test, the print was placed on a piece of filter paper on top of a glass square and immersed in the liquid reagents listed in Table 3. Another piece of filter paper was placed on top, and pressure was provided using the glass square and a 1 kg weight to seal the sandwich. After 18 hours, the weight was removed, the layers were separated, and the print was tapped dry. Any ink removal was recorded. [Table 7]

[0110] Table 3 shows that the inks described herein have bleed resistance comparable to that of the iron oxide inks of the comparative examples and commercially available straw inks.

[0111] Table 8 - SATRA Friction Test SATRA Dry Rub Resistance Test: 100 rubs at a pressure of 2 psi.

[0112] SATRA Wet Rub Resistance Check, 10 rubs, no weight. After the printed material has been immersed in water for 1 hour, rub 10 times with a wet finger at medium pressure.

Table 8

[0113] Paper damage occurs when the printed paper is mechanically or manually rubbed, the fibers of the substrate are broken and worn, and the ink layer comes along with it. Since the ink is absorbed to some extent by the paper, the paper / ink roll can be clearly seen under a magnifying glass. Since the adhesion between the paper fibers cannot withstand wear, this layer is damaged and is indicated by a number less than 5 in the table.

[0114] As can be seen in Table 8, the inks described herein functioned similarly to the comparative inks.

[0115] Other Substrates The inks of Examples 8 - 12 were printed on a white polyethylene film treated up to 44 dynes. The inks were subjected to immersion tests and friction tests.

[0116] Immersion Test: 1 - hour immersion in various reagents After the printed materials were aged overnight, they were immersed in the liquid reagents listed in Table 9 below. Then they were removed after 1 hour, tapped gently and dried, and evaluated to determine if any removal of the printed material was present.

Table 9

Table 10

[0117] In addition, the ink was printed on paper, metallized paper, and polyethylene film. The ink presented a clean color on all of these substrate materials.

[0118] Safety for direct food contact Tables 12 and 13 show the results of the "safety criteria". Along with the concentration of each substance in the printed ink, assumptions were made regarding the weight of the dry ink coating, the degree of substrate surface coverage by the ink on a % basis, the surface area of the print in contact with food, and the weight of the food. The assumed values are documented. Then, a worst-case calculation was performed assuming that 100% of the substances in the ink migrate into the food. The resulting worst-case calculation was then compared with the specific migration limit (SML) to arrive at the results of the safety criteria, which can be as follows:

Table 11

[0119] In addition to the substances causing the color, many commercial products contain other chemical substances (commonly called additives) that are present to improve the application properties of the product, such as the dispersibility, flow, and aggregation resistance of the pigment (dyes often contain significant amounts of diluents). In all cases, the essential colorants are part of the material causing the color and do not contain any additives.

[0120] The following EFSA publications are incorporated herein by reference and relied on the threshold approach to toxicological concerns in the risk assessments elucidated by the European Food Safety Authority (EFSA), and in one case, the World Health Organization (WHO). 1. EFSA Document: Outcome of the public consultation on the draft guidance on the use of the Threshold of Toxicological Concern approach in food safety assessment. APPROVED: 17 May 2019, doi: 10.2903 / sp.efsa.2019.EN-1661 2. EFSA Document: Guidance on the use of the Threshold of Toxicological Concern approach in food safety assessment, ADOPTED: 24 April 2019, doi: 10.2903 / j.efsa.2019.5708 3. EFSA Document: Priority topics for the development of risk assessment guidance by EFSA’s Scientific Committee in 2016 - 2018, ADOPTED: 19 May 2016, doi: 10.2903 / j.efsa.2016.4502 4. EFSA and WHO document: Review of the Threshold of Toxicological Concern (TTC) approach and development of new TTC decision tree. PUBLISHED: 10 March 2016, and 5. EFSA Document: Scientific Opinion on Exploring options for providing advice about possible human health risks based on the concept of Threshold of Toxicological Concern (TTC). EFSA Journal 2012;10(7):2750

[0121] In Europe, the Specific Migration Limit (SML) is derived by assuming that a 60 kg adult consumes 1 kg of food per day. Therefore, by performing the calculation, the unit of the SML can be obtained from mg of the substance per kg of body weight v per day. Also, the paper straw scenario described below is used in this disclosure to evaluate safety.

[0122] Since not all consumers are 60 kg adults, conversion calculations were performed taking into account the body weights of humans of different ages and weights. An example of this calculation is when the risk assessment of a substance indicates that the substance has a Tolerable Daily Intake of 0.05 mg / Kg body weight per day. From that information, the maximum safety limit to which a 60 kg adult consuming 1 kg of food per day can be exposed is 3.0 mg of the substance / kg of food. However, if the consumer is instead a 12.63 kg infant, the maximum safety limit is 0.63 mg of the substance / kg of food.

[0123] Organic pigments are not identified in Tables 11 - 133 because it is not the organic pigment itself that migrates, but other substances (residual starting materials, impurities, additives) present in the pigment. The pigments identified in this specification contain substances with low consumption risks.

[0124] The following Tables 11 - 13 show how all of the materials selected for the ink of the present invention are within the range of the migration guidelines even under severe conditions and worst - case scenarios that exceed various regulatory requirements.

[0125] Table 11 shows information on the substances present in the pigment and the ink. The information includes the substance name, CAS number, source of regulation, and the amount of the substance permitted in food. Regulation (EU) No. 10 / 2011, as referred to in the column with the heading "Restriction as per Regulation (EU) No. 10 / 2011 (as amended)", indicates the specific migration limit of the substance. This regulation can be accessed at: https: / / eur-lex.europa.eu / legal-content / EN / TXT / HTML / ?uri=CELEX:32011R0010&from=EN (last accessed on June 23, 2020). Annex I indicates the specific migration limits of the substances. Article 11 of this regulation states that "For substances for which specific migration limits or other restrictions are not provided in Annex I, a general specific migration limit of 60 mg / kg should be applied."

[0126] Tables 12 and 13 show the migration data for adults (12) and children (13). Although the substances are not named in these tables, the arrangement and order of the substances in these tables are the same as those found in Table 11. Therefore, Table 11 indicates the substance names for Tables 12 and 13.

[0127] The paper straw scenario referred to in Tables 12 and 13 is a version of the EU cube model adjusted to the reduced food contact area of the beverage straw. In this scenario, the printed item in contact with the food (in this case, the beverage) is the paper straw, which has a smaller food contact area than the EU cube model, and it is assumed to cover 0.06 m 2 of packaging for 1 kg of food.

[0128] Figure 6 illustrates the paper straw scenario as the worst - case scenario of a printed paper straw in contact with a beverage. A relatively tall and narrow glass (height 160 mm, diameter 70 mm) is selected for the model. The glass is filled with beverage up to a height of 150 mm. The straw is placed diagonally in the glass to maximize the surface area in contact with the beverage. The length of the straw submerged in the liquid is 160 mm.

[0129] The volume of the liquid in the glass is 35 mm 2 × π × 150 mm = 577267 mm 3 = 577.27 cm 3 Assuming a liquid specific gravity of 1.0, the weight of the liquid is 0.57727 Kg.

[0130] The straw used in the scenario has a diameter of 5 mm. The area of the straw in the liquid is π × 5 mm × 160 mm = 2513 mm 2 = 0.002513 m 2 is.

[0131] Compared with the EU cube exposure scenario of a 0.06 m 2 package covering 1 Kg of food, this exposure scenario differs by a factor of (0.06 / 0.002513) × 0.57727 = 13.8.

[0132] In other words, since the covered area of the paper straw scenario is 13.8 times smaller than that of the EU cube model, the values shown for the paper straw scenario are obtained by dividing the values for the EU cube model by 13.8.

Table 12 - 1

Table 12 - 2

Table 12 - 3

Table 12 - 4

Table 12-5

Table 12-6

Table 12-7

Table 12-8

Table 12-9

Table 13-1

Table 13-2

Table 13-3

Table 13-4

Table 13-5

Table 13-6

Table 13-7

Table 14-1

Table 14-2

Table 14-3

Table 14-4

Table 14-5

Table 14-6

Table 14-7

Table 14-8

Table 14-9

[0133] The following standard assumptions were used in the preparation of Tables 11, 12, and 13: 1) A standard EU exposure model of a 60 kg person consuming 1 kg of food in contact with a printed substrate of 0.06 m 2 was used where the paper straw exposure scenario referenced in this application was not described. 2) 100% coating of ink or varnish 3) A coating weight of 2.0 g / m 2 of ink and overprint varnish was assumed unless otherwise specified. 4) 100% migration of potential substances to food was assumed to ensure that the results were equal to worst-case calculations.

[0134] For those substances with no specific restrictions, a default migration limit of 60 mg / kg food was used. For "unevaluated" substances, a risk assessment was performed according to EFSA principles, i.e., indicated by the abbreviation HA in the column of restricted sources in Table 12.

[0135] The Applicant has decided not to disclose substances present at less than 1.0% of those specific migration limits (SMLs) based on the above worst-case calculation criteria as part of its own internal risk assessment process. This avoids unnecessary disclosure of trace substances that have no reasonable potential to affect compliance with the laws of finished food packaging, materials, or articles, and of course, the status of Sun Chemical products themselves.

[0136] Tables 11 - 13 above represent a worst - case scenario migration analysis to show that the inks and methods of the present invention provide DFC - safe inks under and even beyond regulatory constraints. Tables 14 - 16 below provide the results of analytical tests of the detectable materials in the inks described herein, further indicating that the inks and methods described herein meet or exceed the DFC regulations for all detectable materials in the inks.

[0137] All results in Tables 14 - 16 were obtained using the EU Cube model (ppb, μg / kg).

[0138] Methodology for the analytical data in Tables 14 - 16: Analysis by GC - MS (Gas Chromatography - Mass Spectrometry) showed the migration of some ink - related components. Table 14 includes analytes for which reference materials could be obtained. The levels of these components were calculated against a calibration curve and presented in the table along with their specific migration limits (SML) according to Swiss regulations. All results are given in ppb μg / kg, EU Cube model.

[0139] Analytes for which no reference materials could be obtained are given in Table 15 along with their library match percentage and SML. The library match percentage refers to the % probability that the detected material is the material described in the table when compared to known materials stored in the analytical library. A library match percentage greater than 70 indicates that the material is very likely to be the one described in the chart or a very close equivalent. As seen in Table 15, the library match percentage for each material is > 80. Each analyte is estimated relative to the response of the internal standard.

[0140] All samples contained some peaks that could not be identified by the library used, and the number of unidentified peaks in each sample is also included in Table 15. These unidentified peaks were also seen in the acrylic emulsion material.

Table 15

[0141] The peak first identified as 3,3-dimethyl-1-indanone was found not to be this exact material. The ion pattern of the detected peak was very similar to that seen in 3,3-dimethyl-1-indanone, suggesting that the actual material has a very similar chemical structure. The peak was quantified against a calibration curve for 3,3-dimethyl-1-indanone and is labeled as "unidentified indanone" in Table 14.

Table 16

[0142] References were also obtained for as many components as possible that were highlighted as potentially exceeding the SML of the components in the Specification of the Composition Supplied (SoCS). Only three of these components, diethanolamine, diethanol oleamide, and 4-chlorobenzaldehyde, were found to be soluble in 50% ethanol or 3% acetic acid. The other components obtained were not soluble in these food simulants and are therefore not considered to be migration risks.

[0143] The components that were soluble in 50% ethanol were analyzed by liquid chromatography-mass spectrometry (LC-MS), and the samples were reanalyzed to specifically look for these components.

[0144] Targeted LC-MS analysis of the straw showed the migration of diethanolamine and diethanol oleamide from the DFC yellow sample of Example 8, both of which were at levels significantly below the SML given on the SoCS. These components were either not detected or detected at less than 1 ppb, μg / kg, in all other samples or detected by the EU cube model. 4-Chlorobenzaldehyde was not detected in any of the samples provided (the detection limit for this component was equivalent to 6 ppb μg / kg, EU cube model).

[0145] The results of the LC-MS analysis are given in Table 16. All results are given in ppb, μg / kg, EU cube model.

Table 17

[0146] Methodology: The print, 100 cm 2 was extracted in 20 ml of 50% ethanol at room temperature for 6 hours. After 6 hours, the print was removed and 1 ml aliquots were analyzed by LC-MS (using IM373 instrument parameters). The remaining sample was liquid-liquid extracted in 40 ml of DCM. The DCM was then evaporated to 1 ml and GC-MS (IM304 instrument parameters) was run. The print sample was compared to the unused substrate provided and only ink-related peaks were identified.

[0147] The identified peaks were compared to ethyl acetate-2-cyclohexanone (CAS# 24731-17-7), an internal standard spiked at 3.75 ppm.

[0148] Tables 14 - 16 show the substances in the direct food contact ink together with the safety limits for these substances and the worst-case migration values if all such substances migrated.

[0149] Taking the paper straw scenario related to direct food contact exposure as an example, regarding the range of body weights provided in Tables 12 and 13 of the listed 91 substances and ink combinations, that is, the range from an adult with a body weight of 70.26 kg to an infant with a body weight of 12.63 kg, 76 of these have been shown to be safe for direct food contact by the worst-case calculation method, and 14 substance / ink combinations have safety criteria based on converter control because they have concentrations directly affected by the drying process, which, as shown, are easily manageable, and only one substance-ink combination has a worst-case migration limit exceeding the specific migration limit. For this one substance, migration tests were conducted to demonstrate compliance.

[0150] Regarding the 14 substance / ink combinations for which converter control is the safety criterion, two substances are water (CAS: 7732-18-5) and 2-propanol (CAS: 67-63-0).

[0151] One substance / ink combination that could not be shown to comply by worst-case calculation was 2,4,6(1H,3H,5H)-pyrimidinetrione, 5-(2,3-dihydro-3-oxo-1H-isoindol-1-ylidene)- (CAS: 13481-50-0), which is present in the yellow base.

[0152] Using the EU cube exposure scenario (in contrast to the paper straw scenario), among the 91 substance / ink combinations, the same 14 substance / ink combinations for which converter control is the safety criterion exist, and water and 2-propanol are the substances in question. 67 substance / ink combinations have been shown to be safe by worst-case calculation, and for 10 substance-ink combinations, migration tests are required.

Table 18

[0153] These combinations of substances / inks were shown to be compliant as the substances were not detected above the specific migration limit in the migration test.

[0154] The present invention has been described in detail, including its preferred embodiments. However, those skilled in the art should understand that, in view of the present disclosure, modifications and / or improvements can be made to the present invention within the scope and spirit of the present invention.

Claims

1. A printing ink that is safe for direct food contact and contains an organic colorant of a preselected color, wherein the organic colorant and other chemical substances contained in the ink are evaluated for human exposure to the substances by either worst-case calculation or migration testing, and the risk of the substances is evaluated by either referring to a regulatory positive list or following an EFSA-based substance risk assessment process, and has a migration value determined to be safe for contact with food, and the ink exhibits resistance to removal.

2. The printing ink according to claim 1, wherein the chroma value (C) of the ink is 10% or more of the chroma value (C) of an ink colored with an inorganic colorant of the same color.

3. The printing ink according to claim 1, wherein the chroma value (C) of the ink is 20% or more of an equivalent ink based on an inorganic colorant.

4. The printing ink according to any one of claims 1 to 3, wherein the organic colorant is selected from Paratol Yellow D1818, Irgazine Orange D2905, Irgazine Rubine L4025, Helio Gen Blue D6840, Chromophthal Violet D5700, Sankroma C47-2222, and mixtures thereof.

5. The printing ink according to any one of claims 1 to 4, wherein the organic colorant is selected from pigments corresponding to one of Color Index Yellow 139, Orange 71, Red 264, Red 122, Blue 15:0, Violet 37, Black 7, White 6, and mixtures thereof.

6. The printing ink according to any one of claims 1 to 5, wherein the organic colorant is selected from Isoindoline Yellow, Diketopyrrolopyrrole Orange, Diketopyrrolopyrrole Red, Quinacridone Red, Phthalocyanine Blue, Dioxazine Violet, Carbon Black, Titanium Dioxide, and mixtures thereof.

7. The printing ink according to any one of claims 1 to 6, wherein the migration value of the organic colorant and the other chemical substances is below the threshold for a 60 kg human according to the EU Cube model.

8. The printing ink according to any one of claims 1 to 7, wherein the migration value of the organic colorant and other chemical substances is below the threshold for a 70.3 kg human according to the paper straw scenario.

9. The printing ink according to any one of claims 1 to 8, wherein the migration value of the organic colorant and other chemical substances is below the threshold value for a 40.7 kg human according to the paper straw scenario.

10. The printing ink according to any one of claims 1 to 9, wherein the migration value of the organic colorant and other chemical substances is below the threshold value for a 20.9 kg human according to the paper straw scenario.

11. The printing ink according to any one of claims 1 to 10, wherein the migration value of the organic colorant and other chemical substances is below the threshold value for a 12.7 kg human according to the paper straw scenario.

12. The printing ink according to any one of claims 1 to 11, further comprising an industrial varnish composed of at least some of the other chemical substances.

13. The printing ink according to any one of claims 1 to 12, wherein an aqueous acrylic emulsion safe for food contact is present in the industrial varnish as at least one of the other chemical substances.

14. The printing ink according to any one of claims 1 to 13, wherein wax is present in the ink as at least some of the other chemical substances.

15. The printing ink according to any one of claims 1 to 14, wherein at least some of the other chemical substances include additives selected from adhesion promoters, silicones, light stabilizers, degassing additives, ammonia, flow promoters, defoamers, antioxidants, stabilizers, surfactants, dispersants, plasticizers, rheology additives, waxes, silicones, etc., and combinations thereof.

16. A process for formulating an ink that is safe for direct contact with food, comprising: a) establishing safe migration limits for each material used in the ink system; and b) using only materials that meet the safe migration limits.

17. A process for identifying an organic colorant for an ink that is safe for direct contact with food, comprising: a) establishing safe migration limits for each colorant; and b) selecting a colorant having a chroma value of ≧ 10% compared to an inorganic colorant of a comparative example.

18. A printing ink set that is safe for direct food contact, wherein the inks of the set are of different colors and provide a wide color gamut, the inks of the set contain organic colorants, and the organic colorants and other chemicals containing the inks are evaluated for human exposure to the substances by either worst-case calculation or migration testing, and by referring to a regulatory positive list or by following an EFSA-based substance risk assessment process, and have migration values determined to be safe for contact with food, and the inks exhibit resistance to removal.

19. The printing ink set according to claim 18, wherein the ink set contains red, yellow, orange, blue, purple, black, pink, and transparent colored inks.

20. The printing ink set according to claim 18 or 19, wherein the chroma value (C) of each of the inks of the set is 10% or more of the chroma value (C) of an ink colored with an inorganic colorant of the same color.

21. The printing ink set according to any one of claims 18 to 20, wherein the chroma value (C) of each of the inks of the set is 20% or more of the chroma value (C) of an ink colored with an inorganic colorant of the same color.

22. The printing ink set according to any one of claims 18 to 21, wherein the migration values of the organic colorants and the other chemicals are below the threshold for a 60 kg human according to the EU cube model.

23. The printing ink set according to any one of claims 18 to 22, wherein the migration values of the organic colorants and the other chemicals are below the threshold for a 70.3 kg human according to the paper straw scenario.

24. The printing ink set according to any one of claims 18 to 23, wherein the migration values of the organic colorants and the other chemicals are below the threshold for a 40.7 kg human according to the paper straw scenario.

25. The printing ink set according to any one of claims 18 to 24, wherein the migration values of the organic colorants and the other chemicals are below the threshold for a 20.9 kg human according to the paper straw scenario.

26. The printing ink set according to any one of claims 18 to 25, wherein the migration values of the organic colorant and the other chemical substances are below the threshold value for a 12.7 kg human according to the paper straw scenario.

27. A printed article comprising a substrate and one or more of the printing inks of the set according to any one of claims 18 to 26.

28. The printed article according to claim 27, wherein the article is suitable for direct contact with food.

29. The printed article according to claim 27 or 28, wherein the substrate comprises paper, paperboard, metallized paper, polyethylene, foil, metallized film, and polymer film.

30. The printed article according to any one of claims 27 to 29, wherein the substrate comprises paper.

31. The printed article according to any one of claims 27 to 30, wherein the article is a paper drinking straw.

32. A method of preparing a printed substrate that is safe for direct contact with food, comprising: printing a substrate using one or more of the inks of claims 1 to 15; and drying the substrate.

Images